BACKGROUND OF THE INVENTION

Establishment of a blood-free environment is a prerequisite in reconstructive and orthopedic surgery, which is commonly achieved by tourniquet application. The deprivation of blood and oxygen, termed as ischemia, leads to time-dependent molecular and structural changes of the affected tissue. Complex inflammatory cascades, like the complement, coagulation, as well as the plasma kail ikrein-kinin system, are then activated when blood flow is restored, leading to ischemia/reperfusion injury (IRI). Tourniquet-induced IRI is manifested in edema formation, loss of muscle viability and apoptosis, which significantly affects the outcome of surgical interventions. Furthermore, IRI is known to induce a local as well as a systemic inflammatory response leading to remote tissue and organ damage, a phenomenon which is well known in the clinics. Until now, there are no agents available in the clinics to treat local as well as systemic inflammatory responses after IRI (1 ).

The natural complement inhibitor C1 esterase inhibitor (C1 INH) has been demonstrated to inhibit all three complement pathways (classical, lectin as well as the alternative pathway), the coagulation system as well as the kallikrein-kinin system (2-4). Plasma-derived C1 INH is successfully used in the clinics to treat C1 INH deficient patients suffering from hereditary angioedema (HAE) (2). Several animal studies have demonstrated a therapeutic potential of plasma-derived C1 INH on local IRI, namely solid organ transplantation, myocardial infarction, stroke, hepatic and intestinal IRI (4). Two different studies demonstrated a potential therapeutic effect of plasma-derived C1 INH on local skeletal muscle IRI, attributing the effect to the complement system (5,6). A study using transgenic mice overexpressing human C1 INH with "supraphysiologically" high plasma levels showed a reduction of remote organ damage in lung and skeletal muscle in a model of lower torso IRI (7). However, in this model C1 INH was constitutively expressed, including during embryonic development, which may lead to changes in the physiology and pathophysiological reactivities. So far, no effect of plasma-derived C1 INH on IRI-induced remote tissue or organ damage has been demonstrated.

Surprisingly, using a rat animal model of tourniquet-applied hind limb IRI, the inventors could demonstrate a therapeutic effect of plasma-derived C1 INH not only on local but also on remote tissue and organ damage. For example, a significant reduction of lung edema was observed. C1 INH plays a major role in inhibiting the contact activation system, and its effect on remote tissue and organ damage indicates a major pathophysiological role of the components of this system not only on local tissue and organ damage but also on the remote damage observed during IRI. The results indicate that substances targeting the contact activation system, such as C1 INH, kallikrein inhibitors or Factor XII (FXII) inhibitors, ameliorate or even prevent remote tissue and organ damage.

SUMMARY OF THE INVENTION

The present invention inter alia relates to the subject matter defined in the following items [1 ] to [32].

[1 ]. A contact activation system inhibitor selected from the group consisting of a C1 esterase inhibitor (C1 INH), a kallikrein inhibitor and a Factor XII (FXII) inhibitor for use in the treatment and/or prevention of remote ischemia- reperfusion injury (IRI), comprising administering the contact activation system inhibitor to an individual. [2] The contact activation system inhibitor for use according to item [1 ], wherein the contact activation system inhibitor is a C1 INH, preferably human C1 INH, more preferably human plasma-derived C1 INH or human recombinant C1 INH.

[3] The contact activation system inhibitor for use according to item [1 ], wherein the contact activation system inhibitor is a FXII inhibitor.

[4] The contact activation system inhibitor for use according to any one of the preceding items, wherein the contact activation system inhibitor is administered parenterally to the individual.

[5] The contact activation system inhibitor for use according to any one of the preceding items, wherein the contact activation system inhibitor is administered intravenously, intraarterially or subcutaneously to the individual. [6] The contact activation system inhibitor for use according to any one of the preceding items, wherein the contact activation system is C1 INH and wherein the dose of the C1 INH, administered to the individual is from 1 to 5000 lU/kg body weight, preferably from 1 to 1000 lU/kg body weight, more preferably from 10 to 500 lU/kg body weight.

[7] The contact activation system inhibitor for use according to item [6], wherein the dose of the C1 INH, administered to the individual is from 10 to 250 lU/kg body weight, preferably from 20 to 100 lU/kg body weight. [8] The contact activation system inhibitor for use according to item [3] or [4], wherein the contact activation system inhibitor is a FXII inhibitor, and wherein the dose of the FXII inhibitor administered to the individual is suitable for a complete inhibition of the amidolytic activity of FXIIa. Preferably, when the FXII inhibitor is an antibody, the dose administered to the individual is from 0.01 to 50 mg/kg body weight, preferably from 0.1 to 10 mg/kg body weight. [9] The contact activation system inhibitor for use according to any one of the preceding items, wherein the individual is a patient that is to undergo or has undergone a surgical intervention.

[10] The contact activation system inhibitor for use according to item [9], wherein the contact activation system inhibitor, preferably the C1 INH, is administered to the patient within 7 days, preferably within 6 days, more preferably within 5 days, even more preferably within 4 days before the start of the surgical intervention or start of reperfusion. More preferred is an administration within 72 hours, preferably within 48 hours, more preferably within 24 hours, more preferably within 12 hours, even more preferably within 6 hours before start of the surgical intervention or start of reperfusion.

[1 1 ] The contact activation system inhibitor for use according to item [9] or item

[10], wherein the contact activation system inhibitor, preferably the C1 INH, is administered to the patient during the surgical intervention.

[12] The contact activation system inhibitor for use according to any one of items

[9] to [1 1 ], wherein the contact activation system inhibitor, preferably the C1 INH, is administered to the patient after termination of the surgical intervention or after the start of reperfusion.

[13] The contact activation system inhibitor for use according to item [12], wherein the contact activation system inhibitor, preferably the C1 INH, is administered to the patient within 72 hours, preferably within 48 hours, more preferably within 24 hours, more preferably within 12 hours, even more preferably within 6 hours or most preferably directly after termination of the surgical intervention or start of reperfusion. [14] The contact activation system inhibitor for use according to any one of items [9] to [13], wherein the surgical intervention is reconstructive surgery or trauma surgery. [15] The contact activation system inhibitor for use according to any one of items

[9] to [13], wherein the surgical intervention is orthopedic surgery.

[16] The contact activation system inhibitor for use according to item [15], wherein the orthopedic surgery is selected from the group consisting of knee surgery, shoulder surgery and hand surgery.

[17] The contact activation system inhibitor for use according to any one of items

[9] to [13], wherein the surgical intervention is transplantation. [18] The contact activation system inhibitor for use according to item [17], wherein the transplantation is organ, tissue or cell transplantation, preferably of kidney, liver, lung, intestine, pancreas, heart, extremities (e.g. hand), skin or pancreas islet-cells. [19] The contact activation system inhibitor for use according to any one of items

[9] to [13], wherein the surgical intervention is vascular surgery or surgery to treat crash/crush injuries.

[20] The contact activation system inhibitor for use according to any one of items

[9] to [13], wherein the surgical intervention is insertion of a device, preferably a catheter, to deliver a pharmacologically active substance, such as a thrombolytic substance or a vasodilator, to the individual, or injection of a pharmacologically active substance such as thrombolytic substance or vasodilator, or insertion of a device for the mechanical removal of a complete or partial vascular obstruction. [21 ] The contact activation system inhibitor for use according to item [20], wherein the individual has suffered a myocardial infarction, a stroke, thrombosis, preferably deep vein thrombosis or thrombotic events at foreign surfaces such as stents, thromboembolism, lung embolism, chronic ischemia due to atherosclerosis, preferably chronic limb ischemia due to peripheral atherosclerosis, or other vascular complete or partial obstruction.

[22] The contact activation system inhibitor for use according to item [1 ] to [8], wherein the remote IRI is due to improvement in the impaired blood flow in the individual that is spontaneous or induced by means other than surgical intervention.

[23] The contact activation system inhibitor for use according to item [22], wherein the administration is prior to reperfusion, e.g. prophylactically, or the administration is as soon as possible after reperfusion occurs.

[24] The contact activation system inhibitor for use according to any one of the preceding items, wherein the contact activation system inhibitor is human C1 INH isolated from human plasma.

[25] A method of treating and/or preventing remote ischemia-reperfusion injury (IRI), comprising administering to an individual an effective dose of a contact activation system inhibitor.

[26] A method of preventing ischemia-reperfusion injury (IRI) in a patient that is to undergo or has undergone a surgical intervention, comprising administering to the patient an effective dose of a contact activation system inhibitor prior to and/or during and/or after the surgical intervention, or prior to and/or after start of reperfusion, wherein the ischemia-reperfusion injury (IRI) affects an organ, limb or tissue remote from the site of surgery and/or initial ischemia. [27] The method of item [25] or [26], wherein the contact activation system inhibitor is selected from the group consisting of a C1 INH, a FXII inhibitor, and a kallikrein inhibitor. [28] The method of item [27], wherein the contact activation system inhibitor is a C1 INH, preferably human C1 INH, more preferably plasma-derived human C1 INH.

[29] The method of item [27], wherein the contact activation system inhibitor is a FXII inhibitor.

[30] The method of any one of items [25] to [29], wherein the remote ischemia- reperfusion injury (IRI) affects the lung, the kidney, the brain, the liver, the heart, the intestine, the pancreas or other organs and extremities.

[31 ] The method of any one of items [25] to [30], wherein the ischemia- reperfusion injury (IRI) includes multiple organ dysfunction syndrome or systemic inflammatory response syndrome. [32] The contact activation system inhibitor for use according to item [2], wherein the contact activation system inhibitor is a C1 INH, preferably human C1 INH, and is combined with a synthetic or natural glycosaminoglycans as e.g. heparin, N-acetylheparin, heparan sulfate, dextran sulfates, dermatan sulfates, and chondroitin sulfates, and/or combined with other substances such as intravenous immunoglobulins, antithrombin III, alphal antitrypsin or

FXII inhibitor to improve the therapeutic effect. These substances could be administered as a combination therapy or polytherapy. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 : C1 INH significantly prevents local skeletal muscle edema assessed by the we dry ratio gastronomic muscle. A: we dry ratio analysis. B: Representative picture of non-C1 INH treated (left) and C1 INH treated limb (right). Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 .

Figure 2: C1 INH significantly prevents remote lung edema. Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; p < 0.001 .

Figure 3: Effect of C1 INH on the expression of the bradykinin receptors BiR and B ₂ R in lungs analyzed by IF. A: BiR expression. B: B ₂ R expression. Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 .

Figure 4: C1 INH prevents deposition of fibrin in the lung. Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Mean ± SD data are shown. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 .

Figure 5: C1 INH reduces fibrin deposition in the contralateral leg. Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 .

Figure 6: C1 INH inhibits C3b and factor B deposition in the contralateral limb. Each point represents the value of one animal. A: C3b deposition. B: factor B deposition. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 .

Figure 7: Shedding of heparan sulfate is attenuated by C1 INH in the contralateral limb. Each point represents the value of one animal. Horizontal bar shows the mean of the different animals. Mean ± SD data are shown. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. Statistical significance between samples was indicated as follows *, p < 0.05; **, p < 0.01 ; ***, p < 0.001 . DETAILED DESCRIPTION

In one aspect, the present invention relates to a contact activation system inhibitor, preferably a C1 INH or FXII inhibitor, for use in the treatment and/or prevention of remote ischemia-reperfusion injury (IRI), comprising administering the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, to an individual. The term "treatment" or "treating" shall be understood to include complete curing of a pathological condition as well as amelioration or alleviation of said condition.

The term "prevention" shall be understood to include complete prevention, prophylaxis, reducing the severity of a pathological condition, as well as lowering the individual's risk of falling ill with said condition. This term shall also be understood to include preconditioning of tissue by administering a contact activation system inhibitor, preferably a C1 INH or FXII inhibitor, described herein at a very early stage (e.g. before surgical interventions, before complete diagnosis of remote IRI) so as to prevent the tissue from damages.

The term "individual" refers to a human or animal subject.

The expression "effective amount" is meant to include any amount of an agent according to the present disclosure that is sufficient to bring about a desired therapeutic or prophylactic result, especially upon administration to an individual.

Remote or distant IRI As used herein, the term "ischemia-reperfusion injury" (IRI) refers to an injury resulting from the restoration of blood flow to an area of a tissue or organ that had previously experienced deficient blood flow due to an ischemic event.

An IRI can be caused, for example, by a natural event (e.g., restoration of blood flow following a myocardial infarction), a trauma, or by one or more surgical procedures or other therapeutic interventions that restore blood flow to a tissue or organ that has been subjected to a diminished supply of blood. Such surgical procedures include, for example, coronary artery bypass graft surgery, coronary angioplasty, organ transplant surgery and others. Reperfusion of ischemic tissues results in both a local and a systemic or remote response that, in turn, may result in widespread microvascular dysfunction and altered tissue barrier function. The inflammatory response may even result in the systemic inflammatory response syndrome (SIRS) or the multiple organ dysfunction syndrome (MODS).

As used herein, the phrase "remote IRI" or "distant IRI" or "remote or distant IRI", used interchangeably herein, refers to pathophysiological processes such as thrombotic, thromboembolic and/or inflammatory processes including cellular damage, complement activation and/or edema formation, affecting an organ or tissue which is different from the local ischemic organ(s) and tissue(s) that have been reperfused.

In one embodiment, the remote or distant IRI affects the lung. The remote or distant IRI of this embodiment may include lung edema, thrombotic processes in the lungs, pulmonary embolism and/or inflammation of lung tissue.

In another embodiment, the remote IRI affects the kidney(s). The remote IRI of this embodiment may include renal failure, edema formation, thrombosis, thromboembolism and/or inflammation of renal tissue.

In another embodiment, the remote IRI affects the cardiovascular system. The remote IRI of this embodiment may include myocardial stunning (myocardial dysfunction persisting after reperfusion despite the absence of irreversible damage), thrombosis, reperfusion arrhythmias and/or inflammation/ infarction of myocardial tissue.

In another embodiment, the remote IRI affects the gastrointestinal system, preferably the intestine. The remote IRI of this embodiment may include decreased intestinal barrier function, impaired gut motility and absorption, thrombosis, thromboembolism and/or inflammation of gastro-intestinal tissue. In another embodiment, the remote IRI affects the central nervous system. The remote IRI of this embodiment may include disruption of the blood-brain barrier, silent brain ischemia, stroke, cerebral edema, increased intracranial pressure, and/or inflammation of neuronal tissue.

The remote IRI may be characterized by inflammation, e.g. systemic inflammation. The inflammation may for example affect the lung, the gastrointestinal system, the cardiovascular system, other limbs and/or the central nervous system. The remote IRI may include systemic inflammatory response syndrome (SIRS) and/or multiple organ dysfunction syndrome (MODS).

The ischemic event preceding the remote IRI may due to a surgery, or due to vascular obstructions not caused by surgery.

Surgical interventions

In one embodiment, the remote IRI is due to reperfusion of ischemic tissue(s) and/or organs after a surgical intervention. The surgical intervention includes any surgical procedure.

Possible applications in accordance with this invention include preventing remote IRI by administering the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, in conjunction with surgical repair of the thoracic or suprarenal or abdominal aorta due to aneurysmal disease, but also in conjunction with those surgical procedures that induce or require transient occlusion or bypass of the visceral blood supply during and/or following major organ transplant, including liver, kidney, small intestine, extremities and pancreas. Also included is the prevention of remote IRI in conjunction with surgical procedures that result in the transient reduction or prevention of blood flow including hepatic and biliary surgical resections, total or partial pancreatectomy, total and partial gastrectomy, esophagectomy, colorectal surgery, vascular surgery for mesenteric vascular disease, or abdominal insufflation during laparoscopic surgical procedures. Additional applications include blunt or penetrating trauma that results in interruption of blood flow to the visceral organs including those arising from stab wounds or from penetrating wounds or blunt abdominal trauma secondary to motor vehicle accident. Further applications include crush injuries, for example following a natural disaster. Additional applications include insertion of a device for delivery of pharmacologically active substances such as thrombolytic agents or vasodilators and/or for mechanical removal of complete or partial obstructions, and injection of pharmacologically active substances such as thrombolytic agents or vasodilators following onset of an initial thrombotic or thromboembolic or another ischemia- inducing disorder including but not limited to stroke, myocardial infarction, deep vein thrombosis, atherosclerosis or thrombotic events at foreign surfaces. Preferably, the surgical intervention is selected from the group consisting of orthopedic surgery, vascular surgery, cardiac surgery, catheter-directed procedures, cancer surgery and traumatic surgery. Orthopedic surgery is preferably selected from the group consisting of knee surgery, hand surgery, shoulder surgery, long bones in trauma, hip replacement, and back surgery.

Vascular surgery may be due to repair and/or accidents, for example aortic aneurysms, etc.

In one embodiment, the surgery is traumatic surgery, for example due to car accidents, crash injuries and crush injuries in general, including major trauma with hypovolemia.

In a specific embodiment the surgical intervention is transplantation, preferably of an organ. Vascular obstructions not caused by surgery

Other preferred applications include diseases or procedures that result in systemic hypotension that either disrupts or decreases the flow of blood to the visceral organs, including hemorrhagic shock due to blood loss, cardiogenic shock due to myocardial infarction or cardiac failure, neurogenic shock, nephrogenic shock, or anaphylaxis.

The remote IRI may be due to improvement in blood flow after ischemia due to hypoperfusion leading to peripheral ischemia with or without organ ischemia.

The remote IRI may also be due to improvement in blood flow after initial thrombotic or thromboembolic processes within a primary organ or tissue, e.g. stroke and myocardial infarction.

In one embodiment, the remote IRI is due to improvement in blood flow after a chronic ischemia event such as chronic limb ischemia due to peripheral atherosclerosis. Contact activation system inhibitors

The term "contact activation system inhibitor" as used herein refers to any compound capable of inhibiting the contact activation system. The contact activation system inhibitor is selected from the group consisting of a C1 esterase inhibitor (C1 INH), a Factor XII (FXII) inhibitor, and a kallikrein inhibitor. These inhibitors have the advantage that they act early in the contact activation system pathway, and interact at multiple points in the contact activation system. In contrast, Bradykinin inhibitors, such as Bradykinin receptor antagonists, act at the distal point of the system and the primary point of intervention is at the level of edema formation (cf. Souza et al (10)). C1 esterase inhibitors

C1 esterase inhibitor (C1 INH) from human plasma is a glycosylated single chain polypeptide of 478 amino acid residues. The amino acid sequence of human C1 INH is shown in SEQ ID NO:1 . The average plasma concentration is about 240 g/mL. Synonyms of C1 INH are C1 -esterase inhibitor, a2-neuramino-glycoprotein, C1 s- inhibitor, and C1 -inactivator.

One international unit (IU) of C1 INH is defined by comparison to a WHO International Standard C1 -inhibitor, plasma. The present, 1 ^st International standard is NIBSC code: 08/262, the assigned potency of this preparation is 0.89 lU/ampoule.

As used herein, the term "C1 INH" refers to a polypeptide which comprises an amino acid sequence having at least 90% sequence identity to the amino acid sequence as shown in SEQ ID NO:1 . For the purpose of the present invention, the degree of identity between two amino acid sequences refers to the percentage of amino acids that are identical between the two sequences. The degree of identity of an amino acid sequence to SEQ ID NO:1 is determined by comparing the amino acid sequence in question and SEQ ID NO 1 using the program "BLAST 2 SEQUENCES (blastp)" (Tatusova et al. (1999) FEMS Microbiol. Lett. 174, 247-250) with the following parameters: Matrix BLOSUM62; Open gap 1 1 and extension gap 1 penalties; gap x_dropoff50; expect 10.0 word size 3; Filter: none. According to the present invention, the sequence comparison covers at least 400 amino acids, preferably at least 425 amino acids, more preferably at least 450 amino acids, and most preferably at least 475 amino acids.

The C1 INH preferably has C1 -inhibitory activity that can be assayed as described in Drouet et al. (1988, Clin Chim Acta. 174:121 -30). More preferably, the C1 INH is a human C1 INH having the amino acid sequence as shown in SEQ ID NO:1 (see also UniProt P05155). In one embodiment, the C1 INH has been isolated from human or animal plasma, preferably from human plasma. According to this embodiment the C1 INH is preferably glycosylated like native human C1 INH. In another embodiment, the human or animal C1 INH is obtained from transfected host cells expressing the C1 INH. Such "recombinantly produced" C1 INH may be prepared by any suitable method. It may for example be prepared in a recombinant host cell or organism which has been transfected with DNA encoding the C1 INH. C1 INH suitable for use in the invention can be obtained from culture medium conditioned by modified cells secreting the protein, and purified by standard methods.

The protein or polypeptide may be obtained by recombinant techniques using isolated nucleic acid encoding the C1 INH polypeptide. General methods of molecular biology are described, e.g., by Sambrook et al., Molecular Cloning, A Laboratory Manual, Cold Spring Harbor, N.Y., 2d ed., 1989, and by Ausubel et al., (eds.) Current Protocols in Molecular Biology, New York (1987). The appropriate sequences can be obtained using standard techniques from either genomic or cDNA libraries. Polymerase chain reaction (PCR) techniques can be used. See, e.g., PCR Protocols: A Guide to Methods and Applications, 1990, Innis et al., (Ed.), Academic Press, New York, N.Y. Libraries are constructed from nucleic acid extracted from appropriate cells. Useful gene sequences can be found, e.g., in various sequence databases, e.g., GenBank for nucleic acid and Swiss-Prot for protein.

Standard methods can be used to produce transformed prokaryotic, mammalian, yeast or insect cell lines which express large quantities of the polypeptide. Exemplary mammalian cell lines include COS-7 cells, mouse L cells and CHO cells. See Sambrook (1989), supra and Ausubel et al., 1987, supra. Various expression vectors can be used to express DNA encoding C1 INH. Conventional vectors used for expression of recombinant proteins in prokaryotic or eukaryotic cells may be used. The C1 INH may be produced in soluble form, such as a secreted product of transformed or transfected yeast, insect or mammalian cells. The peptides can then be purified by standard procedures that are known in the art. For example, purification steps could include ammonium sulfate precipitation, ion exchange chromatography, gel filtration, electrophoresis, affinity chromatography, and the like. See Methods in Enzymology Purification Principles and Practices (Springer- Verlag, N.Y., 1982).

Alternatively, C1 INH may be produced in insoluble form, such as aggregates or inclusion bodies. The C1 INH in such a form is purified by standard procedures that are well known in the art. Examples of purification steps include separating the inclusion bodies from disrupted host cells by centrifugation, and then solubilizing the inclusion bodies with chaotropic agent and reducing agent so that the peptide assumes a biologically active conformation. The nucleotide sequences used to transfect the host cells can be modified using standard techniques to make C1 INH or fragments thereof with a variety of desired properties. Such modified C1 INH can vary from the naturally-occurring sequences at the primary structure level, e.g., by amino acid, insertions, substitutions, deletions and fusions. These modifications can be used in a number of combinations to produce the final modified protein chain. The amino acid sequence variants can be prepared with various objectives in mind, including increasing or decreasing serum half-life, facilitating purification or preparation, improving therapeutic efficacy, and lessening the severity or occurrence of side effects during therapeutic use. The amino acid sequence variants are usually predetermined variants not found in nature, although others may be post-translational variants. Such variants can be used in this invention as long as they retain the biological activity of C1 INH. The C1 INH in accordance with this invention includes the C1 INH molecules disclosed in W02007/073186 and US 8,071 ,532 B2.

Expression in host cells may result in a C1 INH with a modified carbohydrate structure (as compared to the plasma derived C1 INH). The C1 INH may be modified compared to the plasma derived C1 INH in one or more of the following aspects: removal of a carbohydrate moiety (from a naturally occurring variant or recombinantly expressed variant of the glycoprotein), preferably the removal of sialic acid and/or galactose from a N-linked carbohydrate chain and/or the removal of a carbohydrate chain resulting in exposure of mannose, galactose, N- acetylglucosamine and/or fucose residues. Furthermore, modifications of C1 INH to increase its plasma half-life are envisaged, for example a fusion with half-life extending moieties such as albumin, immunoglobulin Fc region, or chemical modification such as pegylation or hesylation of C1 INH.

Factor XII inhibitors

The abbreviation "FXII", as used in this application, refers to either or both of Factor XII (FXII) and activated Factor XII (FXIIa). Thus, the term "FXII inhibitor" includes inhibitors of either or both of FXII and FXIIa. Further, anti-FXII antibodies include antibodies that bind to and inhibit either or both of FXII and FXIIa. The term "FXII inhibitor" is also meant to include an inhibitor of FXII that is linked to a half-life extending polypeptide. The FXII inhibitor may be directly linked to the half-life extending polypeptide, or may be linked via a linker, preferably a cleavable linker.

In some embodiments, the FXII inhibitor is a direct inhibitor of FXII. The term "direct" inhibitor means an inhibitor that acts via contact (e.g., binding) with FXII (or FXIIa). In contrast, an indirect inhibitor may act without contacting FXII (or FXIIa) protein; for example, an antisense RNA can be used to decrease expression of the FXII gene or a molecule can inhibit effects of FXIIa via direct interactions with direct downstream FXIIa reaction partners like Factor XI, but it does not interact directly with FXII protein. Thus, an indirect inhibitor, in contrast to a direct inhibitor, acts upstream or downstream from the FXII protein. Some examples of direct inhibitors are presented below. The FXII inhibitors are generally non-endogenous inhibitors; that is, they are not inhibitors that occur naturally in the human or animal body.

A. lnfestin-4

In one embodiment, the application provides a FXII inhibitor comprising Infestin domain 4, lnfestin-4. In one embodiment, a FXII inhibitor comprises a variant of lnfestin-4. In another embodiment, FXII inhibitors comprise Infestin domain 4, and optionally Infestin domains 1 , 2, and/or 3; these proteins are known to be potent inhibitors of FXII (see WO 2008/098720; also see FEBS Lett. 512-516, 2004). The wild type polypeptide sequence of lnfestin-4 is provided (SEQ ID NO: 2). As used herein, the term "variant" refers to a polypeptide with an amino acid mutation, wherein a "mutation" is defined as a substitution, a deletion, or an addition, to the wild type lnfestin-4 sequence, wherein such changes do not alter the functional ability of the polypeptide to inhibit FXII. The term "variant" includes fragments of the wild type or mutated lnfestin-4 sequence. Further examples of such variants are provided below. In one embodiment, an lnfestin-4 variant comprises the N-terminal amino acids 2- 13 of the wild type lnfestin-4 sequence, and at least one and up to five amino acid mutations outside the N-terminal amino acids that result in differences from the wild type lnfestin-4 sequence, or six conserved cysteine residues and homology of at least 70% to the wild type lnfestin-4 sequence. The N-terminal amino acids 2-13 of the lnfestin-4 sequence may be important for binding to FXII based on analysis of structural data for a related inhibitor Rhodnius prolixus (PDB: 1 TSO) binding to thrombin, and analysis of SPINK-1 binding to chymotrypsin, which both share a common feature of the accumulation of contact sites in the N-terminal region. Therefore in one embodiment, a variant of lnfestin-4 comprises the conserved N- terminal region of amino acids 2-13 of the wild type lnfestin-4 sequence, and at least one and up to five amino acid mutations outside these conserved N-terminal amino acids that result in differences from the wild type lnfestin-4 sequence. A mutation may be a substitution, a deletion, or an addition. As used herein, the term "outside said N-terminal amino acids" refers to any amino acid along the polypeptide chain of the variant other than the contiguous stretch of amino acids that comprises the sequence VRNPCACFRNYV, i.e., amino acids 2-13 from the wild type lnfestin-4 sequence. In another embodiment, an lnfestin-4 variant comprises six conserved cysteine residues and has homology of at least 70% to the wild type lnfestin-4 sequence. In one embodiment, the six conserved cysteine residues are amino acids at positions 6, 8, 16, 27, 31 , and 48 of the wild type lnfestin-4 sequence. In one embodiment, the variant comprises the final conserved cysteine. In other embodiments, the exact positions of the cysteine residues, and relative positions to each other, may change from positions 6, 8, 16, 27, 31 , and 48 of the wild type lnfestin-4 sequence due to insertions or deletions in the lnfestin-4 variant. Nevertheless, in these embodiments, an lnfestin-4 variant comprises all six cysteines and may share 70%, 75%, 85%, 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% homology to the wild type lnfestin-4 sequence.

In embodiments, a variant of lnfestin-4 is characterized in that it inhibits FXII. The functional activity of inhibiting FXII may be assessed for example, through in vitro and/or in vivo characterization, including direct assays to test inhibition of FXII enzyme activity, prolonged coagulation time, i.e. activated partial thromboplastin time (aPTT), or in vivo methods that evaluate coagulation. Further examples of lnfestin-4 variants are SPINK-1 mutants, which are described below. B. SPINK-1 mutants

One embodiment involves FXII inhibitors for therapeutic use in humans. A human protein with high similarity to lnfestin-4 may be employed. For example, the human protein with the highest similarity to lnfestin-4 is SPINK-1 , a Kazal-type serine protease inhibitor expressed in the pancreas (also known as pancreatic secretory trypsin inhibitor, PSTI). The Kazal-type serine protease inhibitor family is one of numerous families of serine protease inhibitors. Many proteins from different species have been described (Laskowski M and Kato I, 49 Ann. Rev. Biochem. 593-626, 1980). Based on the wild type SPINK-1 sequence different variants may be generated in order to increase homology of the SPINK-1 sequence to lnfestin-4. The phrase "increased homology to lnfestin-4" refers to the process whereby amino acid mutations are made to SPINK-1 to bring the SPINK-1 sequence closer to the lnfestin-4 sequence.

In one embodiment, SPINK-1 is mutated to comprise the N-terminal amino acids 2- 13 of the wild type lnfestin-4 sequence; the polypeptide sequence is given and is referred to as K1 . As described above, the N-terminal portion of the lnfestin-4 sequence is thought to be important for FXII inhibitory function.

Therefore, in one embodiment, a variant of the mutated SPINK-1 also comprises N- terminal amino acids 2-13 of the wild type lnfestin-4 sequence, and at least one and up to five amino acid mutations outside said N-terminal amino acids that result in differences from the wild type SPINK-1 sequence and which increase the homology of the variant to the wild type lnfestin-4 sequence. In another embodiment, a variant of mutated SPINK-1 comprises six conserved cysteine residues and has homology of at least 70% to the wild type SPINK-1 sequence. A mutation may be a substitution, a deletion, or an addition. As defined above, the term "outside said N- terminal amino acids" refers to any amino acid along the polypeptide chain of the variant other than the contiguous stretch of amino acids that is comprised of the sequence VRNPCACFRNYV, i.e., amino acids 2-13 from the wild type lnfestin-4 sequence. The term "variant" includes fragments of said mutated SPINK-1 sequence. In one embodiment, the six conserved cysteine residues may be amino acids at positions 9, 16, 24, 35, 38, and 56 of the wild type SPINK-1 sequence. In one embodiment, the variant comprises the final conserved cysteine. In another embodiment, the exact positions of the cysteines, and relative positions to each other, may change from positions 9, 16, 24, 35, 38, and 56 of the wild type SPINK-1 sequence due to insertions or deletions in the SPINK-1 variant. Nevertheless, in these embodiments, a SPINK-1 variant comprises all six cysteines. In embodiments, a SPINK-1 variant is also characterized in that it inhibits FXII. Further SPINK variants are disclosed in EP 2497489A1 the disclosure of which is incorporated herein in its entirety. C. Other FXII inhibitors

In one embodiment, other inhibitors of FXII are administered to a patient receiving a medical procedure. As discussed above, the term inhibitors of FXII includes inhibitors of both FXII and FXIIa. In W02006/066878 the use of antibodies against FXII or the use of inhibitors of FXII is proposed. Specifically, inhibitors to FXII include antithrombin III (ATI 11), angiotensin converting enzyme inhibitor, aprotinin, alpha-1 protease inhibitor , antipain ([(S)-1 -Carboxy-2-Phenylethyl]-Carbamoyl-L- Arg-L-Val-Arginal), Z-Pro-Proaldehyde-dimethyl acetate, DX88 (Dyax Inc., 300 Technology Square, Cambridge, MA 02139, USA; cited in: Williams A and Baird LG, 29 Transfus Apheresis Sci. 255-258, 2003), leupeptin, inhibitors of prolyl oligopeptidase such as Fmoc-Ala-Pyr-CN, com-trypsin inhibitor, mutants of the bovine pancreatic trypsin inhibitor, ecotin, yellowfin sole anticoagulant protein, Cucurbita maxima trypsin inhibitor-V including Curcurbita maxima isoinhibitors and Hamadarin (as disclosed by Isawa H et al. 277 J. Biol. Chem. 27651 -27658, 2002 ). In still other embodiments, the FXII inhibitor is H-D-Pro-Phe-Arg- chloromethylketone (PCK). (Tans et al., Eur. J. Biochem. 1987; 164:637-42; Kleinschnitz et al., J Exp Med. 2006; 203:513-8.)

The FXII inhibitor may be for example an analogue of Kunitz Protease Inhibitor domain of amyloid precursor protein as disclosed in U.S. Patent No. 6,613,890 in columns 4 through 8.

In another embodiment, the FXII inhibitor may be an anti-FXII antibody that binds to FXII and inhibits FXII activation and/ or activity. Such an antibody has been described for example in WO 2006/066878, and in Ravon et al., 1 Blood 4134-43, 1995. Other monoclonal antibodies (mAbs) to human FXII include the B7C9 mAb described by Pixley et al (J Biol Chem 1987; 262, 10140-45), a mAb described by Small et al {Blood 1985; 65:202-10); the mAbs F1 and F3 described by Nuijens et al (J. Biol. Chem. 1989; 264:12941-49); the B6F5, C6B7, and D2E10 mAbs against the light chain of FXII described in WO89/1 1865; a mAb that selectively binds FXIIa-β over FXII described in WO90/08835; and the anti-FXII antibody OT-2 described in WO91/17258.

Additional preferred anti-FXII/FXIla monoclonal antibodies and antigen-binding fragment thereof are described in WO 2013/014092, which is incorporated herein by reference. Those antibodies have a more than 2 fold higher binding affinity to human FXIIa-beta than to human FXII and are capable of inhibiting the amidolytic activity of human FXIIa. In some embodiments, the antibody or antigen-binding fragment has one or more of the following features: (a) binds murine FXII/FXIla; (b) comprises a heavy chain variable (VH) region which is more than 85% identical to the sequence of SEQ ID NO: 7; (c) comprises a light chain variable (vL) region which is more than 85% identical to the sequence of SEQ ID NO: 8; (d) comprises heavy chain CDR1 at least 80% identical to the sequence of SEQ ID NO: 9, and/or heavy chain CDR2 at least 60% identical with SEQ ID NO: 10, and/or heavy chain CDR3 at least 80% identical to the sequence of SEQ ID NO: 12; (e) comprises light chain CDR1 at least 50% identical with SEQ ID NO: 14, and/or light chain CDR2 of SEQ ID NO: 15, and/or light chain CDR3 with the sequence

X ₆ -X ₇ wherein Xi can be A or S, X ₅ can be L or V, the other X _n s can be any amino acid (SEQ ID NO: 17); (f) binds human FXIIa-beta with a K _D of better than 10 ^"8 M; (g) competes with infestin-4, for binding to human FXIIa-beta; or (h) is a human IgG or variant thereof, preferably human lgG4 or variant thereof.

In other embodiments, the anti-FXII antibody is an IgG antibody that binds human FXII and comprises (a) a VH region comprising heavy chain CDR1 as set forth in SEQ ID NO: 9, heavy chain CDR2 as set forth in SEQ ID NO: 1 1 , and heavy chain CDR3 as set forth in SEQ ID NO: 13; and/or (b) a VL region comprising light chain CDR1 as set forth in SEQ ID NO: 14, light chain CDR2 as set forth in SEQ ID NO: 15, and light chain CDR3 as set forth in SEQ ID NO: 17. A heavy chain CDR2 comprising SEQ ID NO: 1 1 comprises the sequence GIX ₁ X ₂ X3X ₄ X5X6TVYADSVKG, wherein Xi is R, N or D, X ₂ is P, V, I, or M; X ₃ is S, P, or A; X ₄ is G, L, V, or T; X ₅ can be any amino acid, preferably X ₅ is G, Y, Q, K, R, N, or M; and Χβ is T, G, or S. A heavy chain CDR3 comprising SEQ ID NO: 13 comprises the sequence ALPRSGYLX ₁ X ₂ X ₃ X ₄ YYYYALDV, wherein Xi is I, M or V; X ₂ is S or K; X ₃ is P, K, T, or H; and X ₄ is H, N, G, or Q. A light chain CDR3 comprising SEQ ID NO: 17 comprises the sequence AXiWX ₂ X3X ₄ X5RX6X7, wherein Xi is A or S; X ₂ is D, Y, E, T, W, E, or S,; X ₃ is A, N, I, L, V, P, Q, or E; X4 is S, D, P, E, Q, or R; X ₅ is L or V; X ₆ is G, L, or K; and X ₇ is V, A, D, T, M, or G.

In other embodiments, the anti-FXII antibody antigen-binding fragment is a fragment of an IgG antibody that binds human FXII and comprises (a) a VH region comprising heavy chain CDR1 as set forth in SEQ ID NO: 9, heavy chain CDR2 as set forth in SEQ ID NO: 10, and heavy chain CDR3 as set forth in SEQ ID NO: 12; and/or (b) a VL region comprising light chain CDR1 as set forth in SEQ ID NO: 14, light chain CDR2 as set forth in SEQ ID NO: 15, and light chain CDR3 as set forth in SEQ ID NO: 16.

In one embodiment, the anti-FXII antibody or antigen-binding fragment thereof is the antibody "3F7" used in Example 3. Sequences of the variable regions and CDRs of 3F7 are presented in Table 1 .

Table 1

Region Amino acid sequence

VH EVQLLESGGGLVQPGGSLRLSCAASGFTFSKYIMQWVR QAPGKGLEWVSGIRPSGGTTVYADSVKGRFTISRDNSK NTLYLQMNSLRAEDTAVYYCARALPRSGYLISPHYYYYA LDVWGQGTTVTVSS (SEQ ID NO: 7)

VL QSELTQPPSASGTPGQRVTISCSGSSSNIGRNYVYWYQ QVPGTAPKLLIYSNNQRPSGVPDRFSGSKSGTSASLVIS GLRSEDEADYYCAAWDASLRGVFGGGTKLTVLG (SEQ ID NO: 8)

HCDR 1

KYIMQ (SEQ ID NO: 9)

(Kabat 31-35)

HCDR 2

G I RPSGGTTVYADSVKG (SEQ ID NO: 10)

(Kabat 50-65)

HCDR 3

ALPRSGYLISPHYYYYALDV (SEQ ID NO: 12)

(Kabat 95-102)

LCDR 1

SGSSSNIGRNYVY (SEQ ID NO: 14)

(Kabat 24-34)

LCDR 2

SNNQRPS (SEQ ID NO: 15)

(Kabat 50-56)

LCDR 3

AAWDASLRGV (SEQ ID NO: 16)

(Kabat 89-97)

In still other embodiments, the anti-FXII antibody or antigen binding fragment is chosen from the affinity matured (relative to 3F7) antibodies VR1 15, VR1 12, VR24, VR1 10, VR1 19. Table 2

As noted above SEQ ID NO: 1 1 is a degenerate sequence. VR1 19 comprises SEQ ID NO: 1 1 wherein Xi is N, X ₂ is V, X ₃ is P; X ₄ is L, X ₅ Y; and X ₆ is G. VR1 12 comprises SEQ ID NO: 1 1 wherein Xi is N, X ₂ is V, X ₃ is P, X4 is V, X ₅ is Q, and Xe is G. VR1 15 comprises SEQ ID NO: 1 1 wherein Xi is D, X ₂ is I, X ₃ is P, X ₄ is T, X ₅ is K, and X ₆ is G. VR1 10 comprises SEQ ID NO: 1 1 wherein Xi is D, X ₂ is M, X ₃ is P, X4 is T, X ₅ is K, and Xe is G. VR24 comprises a unique LCDR1 : SGSSEMTVHHYVY (SEQ ID NO: 18). In embodiments involving antibody CDRs, CDR's are defined according to the KABAT numbering system. (Kabat EA, Wu TT, Perry HM, Gottesman KS, Foeller C (1991 ) Sequences of proteins of immunological interest, 5th edn. U.S. Department of Health and Human services, NIH, Bethesda, MD.) In some embodiments, the antibody or antigen-binding fragment thereof is an anti- FXII/FXIla monoclonal antibody or antigen-binding fragment thereof that inhibits FXIIa-alpha by more than 40%, more than 50%, or more than 60%, when used at a molar ratio of FXIIa-alpha to antibody of 1 :0.2. In some embodiments, the antibody or antigen binding fragment thereof inhibits FXIIa-alpha by more than 80%, more than 85%, or more than 90%, at a molar ratio of FXIIa-alpha to antibody of 1 :0.5. In one embodiment, the antibody achieves complete inhibition of FXIIa-alpha at a molar ratio of 1 :0.5. In one embodiment, the FXIIa-alpha is human FXIIa-alpha. In one embodiment, the antibody or antigen binding fragment thereof has an affinity for human FXIIa that is at least comparable to antibody 3F7.

As discussed above, an "anti-FXIl antibody" includes antibodies that bind to and inhibit either or both of FXII and FXIIa. In one embodiment, the antibody may be in the form of a full length Ig, Fab, F(ab)2, Fv, scFv, or other form or variant thereof. The antibody may be monoclonal or polyclonal. The antibody may be characterized in that the isotype is IgM, IgD, IgA, IgG, or IgE, or any subclass thereof, such as Igd, or variants thereof. The antibody may be from a mammalian species, including, but not limited to human, mouse, rat, rabbit, goat, hamster, or monkey. The antibody may be humanized or CDR-grafted. The antibody maybe mutated or modified to alter immunogenicity, half-life, or to impart other advantageous properties associated with a therapeutic antibody. In one embodiment, the antibody is an anti-FXIl antibody that binds to an epitope on the heavy chain or light chain of FXII (wherein, "FXII" includes FXII and FXIIa), such as a neutralizing epitope. The antibody may be high affinity and/or high avidity for binding to FXII. The antibody may be conjugated to a polypeptide, nucleic acid or small molecule.

D. FXII inhibitors linked to half-life extending moieties Polypeptides

Another aspect of the application provides FXII inhibitors linked to a half-life enhancing polypeptide (HLEP). For example, in one embodiment, FXII inhibitors are linked to half-life extending proteins. A "half-life enhancing polypeptide" increases the half-life of the FXII inhibitor in vivo in a patient or in an animal. For example, albumin and immunoglobulins and their fragments or derivatives have been described as half-life enhancing polypeptides (HLEPs). Ballance et al. (WO 2001/79271 ) described fusion polypeptides of a multitude of different therapeutic polypeptides which, when fused to human serum albumin, are predicted to have an increased functional half-life in vivo and extended shelf life. The embodiments relating to FXII inhibitors linked to half-life enhancing polypeptides disclosed in EP 2497489 A1 can be used in accordance with the present invention and are incorporated herein by reference.

E. Linkers

In one embodiment, an intervening peptidic linker may be introduced between the therapeutic polypeptide and the HLEP. In one embodiment, a cleavable linker is introduced, particularly if the HLEP interferes with the therapeutic polypeptide's specific activity, e.g. by steric hindrance. In certain embodiments, the linker is cleaved by enzymes such as coagulation proteases of the intrinsic, extrinsic, or common coagulation pathway. Coagulation proteases of the intrinsic pathway are proteases in the contact activation pathway, including, for example, FXIIa, FXIa, or FIXa. In one embodiment, the linker is cleaved by FXIIa. Proteases of the extrinsic pathway include proteases in the tissue factor pathway, for example, FVIIa. Proteases of the common pathway includes proteases involved in the conversion of fibrinogen to fibrin, for example, FXa, Flla, and FXIIIa. Combinations / Kits

Another aspect of the invention is the combination of C1 INH with agents. Preferably C1 INH may be administered combined with a synthetic or natural glycosaminoglycans as e.g. heparin, N-acetylheparin, heparan sulfate, dextran sulfates, dermatan sulfates, and chondroitin sulfates which are known to potentiate the activity of C1 INH. In addition, C1 INH may be combined with other substances including, but not limited to, intravenous immunoglobulins, antithrombin III, alphal antitrypsin or FXII inhibitor, to improve the therapeutic effect. These substances could be administered as a combination therapy or polytherapy. Therefore, kits comprising C1 INH and one or more of the substances mentioned above, for the use in prevention and/or treatment of remote IRI including instructions for administration are also aspects of the invention. An embodiment of the invention is therefore a kit of parts comprising C1 INH and at least one other substance as listed above for the simultaneous, separate or sequential use in the prevention and/or treatment of remote IRI.

Administration The contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, described herein is preferably administered as part of a pharmaceutical composition comprising the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, and a pharmaceutically acceptable excipient. The pharmaceutical composition can be easily administered parenterally such as for example, by intravenous, intraarterial, intramuscular, intraperitoneal, intrathecal, intranasal, intrapulmonal, dermal or subcutaneous application. Parenteral administration can be accomplished by incorporating the compositions of the present invention into a solution, emulsion or suspension. Preferably, the composition comprising the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered intravenously, intraarterially, or subcutaneously either by single or multiple bolus-injection(s) and/or by continuous infusion or infusions over a certain period of time.

Alternatively, the pharmaceutical composition could be administered enterally such as for example, by oral or rectal application.

The dose of the C1 INH to be administered to the individual ranges from 1 to 5000 lU/kg body weight. Preferably, the dose is within the range from 1 to 2500 lU/kg, more preferably from 1 to 500 lU/kg, even more preferably from 10 to 500 lU/kg body weight. Most preferably, the dose ranges from 10 lU/kg to 250 lU/kg body weight, or even from 20 lU/kg to 100 lU/kg body weight. The skilled person will be aware of the need to adjust the dose depending on various factors, such as route of administration. The dose range of FXII inhibitors is adjusted according to the type of inhibitor used, route of administration and other factors the skilled person will be well aware of. The dose and dosing interval is preferably chosen so that the amidolytic activity of FXIIa is completely inhibited for the desired period of treatment. For example, a FXII inhibitory antibody would be administered in a dose ranging from 0.01 to 50 mg/kg body weight, from about 0.01 to 30 mg/kg, from about 0.1 to 30 mg/kg, from about 0.1 to 10 mg/kg, from about 0.1 to 5 mg/kg, from about 1 to 5 mg/kg, from about 0.1 to 2 mg/kg or from about 0.1 to 1 mg/kg. The treatment may comprise giving a single dose or multiple doses. If multiple doses are required, they may be administered daily, every other day, weekly, biweekly, monthly, or bimonthly or as required. A depository may also be used that slowly and continuously releases the antibody or antigen-binding fragment thereof. A therapeutically effective dose may be a dose that inhibits FXIIa in the subject by at least 50%, preferably by at least 60%, 70%, 80%, 90%, more preferably by at least 95%, 99% or even 100%. In case of an infestin-based FXII inhibitor, e.g. albumin-fused infestin-4, the dose may be between 0.1 and 1000 mg/kg body weight, preferably between 1 and 1000 mg/kg, more preferably between 1 and 500 mg/kg, even more preferably between 50 and 500 mg/kg.

For these and other FXII inhibitors, the skilled person will be able to adjust the dose as required by the treatment, and will be aware of the factors influencing the required dose, such as route of administration, half-life of the inhibitor, inhibitory activity of the inhibitor, affinity to FXIIa of the inhibitor and such like.

For the treatment of remote or distant IRI caused by therapeutic interventions, such as surgical procedures, it is preferable that the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to an individual undergoing treatment prior to the surgical intervention (e.g. limb surgery, cardiac surgery, organ transplantation, etc.). In one aspect, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is therefore administered to the individual prior to the start of a surgical intervention.

The contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, may be administered to the patient within one week, 6 days, 5 days, 4 days, or 72 hours, preferably within 48 hours, more preferably within 24 hours prior to start of the surgical intervention, even more preferably within 12 hours, most preferably within 6 hours before the start of the surgical intervention.

For example, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered to an individual undergoing treatment, e.g., about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 12 hours, about 24 hours, about 36 hours, about 48 hours or about 72 hours prior to the surgical intervention. The contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can also be administered to an individual undergoing treatment, for example, about 5 minutes, about 10 minutes, about 15 minutes, about 20 minutes, about 30 minutes or about 45 minutes prior to the therapeutic intervention. Alternatively, or in addition, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered to an individual undergoing treatment at the time of, or during, the surgical intervention. In another embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is therefore administered to the patient during the surgical intervention. For example, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered one or more times during the course of a surgical intervention in intervals (e.g., 15 minute intervals). Alternatively, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered continuously throughout the duration of a therapeutic intervention.

Furthermore, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered to an individual undergoing treatment after a surgical intervention. In yet another embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient after termination of the surgical intervention, preferably within a period of 72 hours after termination of the surgical intervention. For example, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can be administered to a subject undergoing treatment, e.g., about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 12 hours, about 24 hours, or about 48 hours after the surgical intervention. The contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, can also be administered to a subject undergoing treatment, for example, about 5 minutes, about 10 minutes, about 15 minutes, about 20 minutes, about 30 minutes or about 45 minutes after the surgical intervention. Preferably, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered as soon as possible after the surgical intervention, and treatment is maintained for at least 24 hours, preferably at least 48 hours, more preferably at least 72 hours after the surgical intervention or longer if required. In yet another embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient during the surgical intervention and after termination of the surgical intervention. In a further embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient prior to the start of the surgical intervention, during the surgical intervention and after termination of the surgical intervention. In a further embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient prior to the start of the surgical intervention and after termination of the surgical intervention, but not during the surgical intervention. In a further embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient prior to the start of the surgical intervention and during the surgical intervention, but not after termination of the surgical intervention. In a further embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered prior to the start of reperfusion. Preferably, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered up to one week prior to reperfusion, up to 6 days, 5 days, 4 days, preferably up to 72 hours, more preferably up to 48 hours, even more preferably up to 24 hours, up to 12 hours, most preferably up to 6 hours prior to reperfusion.

In yet a further embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered after the start of reperfusion. Preferably, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered up to 72 hours after the start of reperfusion, more preferably up to 48 hours, up to 12 hours, even more preferably up to 6 hours, most preferably immediately after the start of reperfusion.

In a preferred embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered prior to the start of reperfusion and after the start of reperfusion. Preferably, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered up to one week prior to reperfusion, up to 6 days, 5 days, 4 days, preferably up to 72 hours, more preferably up to 48 hours, even more preferably up to 24 hours, up to 12 hours, most preferably up to 6 hours prior to reperfusion, and the treatment is then maintained for a period after the start of reperfusion, preferably at least for 72 hours, more preferably for at least 4 days, even more preferably for at least one week, most preferably for 2 weeks or longer if required. In a specific embodiment, the contact activation system inhibitor, preferably the C1 INH or FXII inhibitor, is administered to the patient for less than 1 month, preferably for less than 14 days, more preferably for less than 7 days, most preferably for less than 48 hours.

Examples

Materials and Methods Animals and housing

All Experiments were conducted under the term of the Swiss Animal Protection Law and were approved by the animal ethics committee of the cantonal veterinary service (Cantone of Bern, Switzerland). Male Wistar rats (wild type, internal animal facility, University of Bern) were kept at three per cage under standard housing conditions with food and water ad libitum. Animals were housed in thermoneutral environment of 20 ± 2°C and indoor humidity of 45 % - 65 % controlled rooms in which a circadian rhythm of 12/12 h (based on winter time) was maintained. During the light cycle animals were exposed to an intensity of 200 lux.

Reagents

C1 INH (Berinert ^® ) and the vehicle (10 mg/mL glycine, 2.9 mg/mL sodium citrate and 8.5 mg/mL sodium chloride) were provided by CSL Behring AG (Bern, Switzerland). C1 INH was administered as a bolus via the tail vein by using an I.V. cannula (BD Vasculon Plus) 5 minutes before induction of ischemia.

FXIIa inhibitor rHA-lnfestin-4 (Hagedorn et al, 2010, Circulation 121 :1510-1517) is administered as a bolus via the tail vein at a dose of 100 mg/kg 5 minutes before induction of ischemia.

Surgical procedure

Male Wistar rats weighing between 250 and 350 g were used for the following experiments. Induction of anesthesia was performed with 2.5% isoflurane in oxygen in an anesthetic induction chamber and later maintained by inhalation of 1 .5% isoflurane via a nose mask. For assessment of limb perfusion the fur was completely removed from both hind limbs with an electric shaver. The rats were kept on a heating pad to maintain the body temperature at 37°C. Approximately, thirty min after the induction of anesthesia, unilateral hind limb ischemia was induced for 3 h. Ischemia was induced by clamping the femoral artery. Therefore, an incision in the groin area was conducted, the fatty tissue was carefully removed and the femoral vessels were exposed. Next the femoral artery was isolated from the vein.

Before clamping the artery a tourniquet (standardized weight of 450 g) was placed underneath the femoral vessels like described before (8). The femoral artery was transiently occluded with two microvascular clamps (B1 -V, S&T Switzerland). Immediately, the tourniquet was tightened to block microvascular blood flow. During the whole procedure the hemodynamics were monitored (Mouse ox plus, Starlifesciences). After 3 hours of ischemia the limb was reperfused for 24 hours, respectively. During 24 hours reperfusion rats woke up and were treated with analgesia (Buprenorphine, 0.05 mg/kg, Temgesic Reckitt Benckiser (Switzerland AG)). At the end of the experiment, the lung as well as both the ischemic and contralateral gastrocnemic muscles were taken for analysis. Assessment of edema formation

For assessment of edema formation two samples of the gastrocnemic muscle from both legs were taken and immediately weighed to obtain the wet weight. The muscle samples or lungs were dried for 24 hours at 80°C until a constant weight could be achieved. In a second weighing step the dry weight was obtained. Subsequently, the wet weight to dry weight ratio was calculated and compared with the wet to dry weight ratio of the contralateral control muscle. Determination of deposited complement components and other proteins in muscle and lung tissue

Immunofluorescence (IF) was used to quantify the deposition of various components of the complement system as well as Fibrin/ Fibrinogen, Heparan Sulfate, Bradykinin receptor Bi and Bradykinin receptor B ₂ . Tissue sample from the gastrocnemic muscle of both legs and the lung were taken, washed in PBS, blotted dry and embedded in matrix (OCT, Tissue tek) on dry ice. Immediately, the samples were stored at -20 °C until cryosections were cut (Cryostat, Leica CM 3050S). Sections were fixed with acetone and rehydrated in TBS. Primary antibodies were incubated over night at 4°C and the following secondary antibodies were incubated for 1 hour at room temperature. Subsequently, slides were mounted and covered. Pictures were taken with the fluorescent microscope (Leica) and analyzed by using Image J software.

Cytokine/ Chemokine measurement using multiplex array

A multiplex immunoassay consisting of magnetic beads conjugated with a capture antibody specific for a target protein was used to detect an array of cyto- and chemokines (Bioplex Pro™ Rat Cytokine Group I panel, BioRad, Hercules, USA). The assay was performed according to manufacturer's instructions.

Briefly, plasma was diluted 1 :3 and incubated with antibody-coupled magnetic beads. A washing step was followed by incubation with biotinylated detection antibody. After streptavidin-phycoerythrin incubation the concentration of cytokines/chemokines was measured. Recombinant cytokines/chemokines were used to establish standard curves. Analyte concentrations were calculated using the Bio-Plex Manager 4.0 Software (Bio-Rad, Hercules, USA). Assessment of apoptosis by TUNEL assay

Apoptosis was assessed by using a TdT-mediated dUTP nick end-labeling (TUNEL) assay (in situ Cell Death Detection Kit, TMR red, Roche, Mannheim, Germany). In brief, cryosections of tissue samples were fixed in acetone for 5 minutes at room temperature, washed and permeabilized with 0.1 % Triton-X-100 on ice. Sections were incubated with TUNEL reaction mixture for 1 h at 37°C in the dark and counterstained with DAPI. After a washing step sections were mounted, coverslipped and analyzed with a fluorescent microscope. Immunofluorescence images were analyzed with image J (National Institutes of Health, Bethesda, MD, USA). The area in % covered by TUNEL-positive nuclei was analyzed and calculated in relation to the area covered by all DAPI-stained nuclei.

Statistical analysis

Data are expressed as means ± SD. Statistical significance was determined by one-way analysis of variance with Dunnetts post-test using the GraphPad Prism 5 software. P values < 0.05 were considered statistically significant. Results i) Effect of C1 INH on local IRI tissue damage

C1 INH prevented local IRI induced skeletal muscle edema

As a first step, the therapeutic effect of C1 INH (50 lU/kg) was assessed by prevention of local edema formation in the hind limb. Systemic preload of the animal with human plasma-derived C1 INH highly significantly prevented the formation of skeletal muscle edema (see Fig. 1A and B). Similar results, i.e. reduction in muscle edema formation, are expected using a FXII inhibitor eg. a monoclonal anti-FXII antibody or rHA-lnfestin-4. ii) Effects of C1 INH on IRI induced remote tissue and organ damage C1 INH inhibited remote organ damage by attenuating lung edema

The effect of C1 INH on remote tissue and organ damage was analyzed. C1 INH is a very potent inhibitor the plasma kallikrein-kinin system by interacting with FXIIa and kallikrein. As shown in Fig. 2, C1 INH significantly prevented the formation of edema as analyzed by the we dry ratio and therefore endothelial cell integrity in the lung was preserved.

Effect of C1 INH on the expression of bradykinin receptors in the lung and the heart Activation of plasma kallikrein-kinin system results in the generation of bradykinin. This molecule is a very potent vasoactive peptide inducing vasodilation and edema. The kallikrein-kinin system has been shown to be a crucial player of IRI. An antagonist of the bradykinin 2 receptor (B ₂ R) has been successfully used in the clinics to treat HAE patients (9). The effect of C1 INH on BiR and B ₂ R expression was analyzed by IF. Surprisingly, C1 INH significantly inhibited IRI induced upregulation of BiR in lung tissue (see Fig. 3A) whereas no inhibition could be observed for the expression of B ₂ R (see Fig. 3B). The same effect was observed in heart tissue (data not shown). C1 INH inhibited fibrin deposition in the lung

Beside complement inhibition, C1 INH acts on the coagulation system by interaction with FXII and FXI. Activation of the coagulation system results in the generation of thrombin which cleaves fibrinogen into fibrin. Treatment with C1 INH significantly inhibited fibrin deposition in the lung tissue (see Fig. 4). C1 INH prevented remote tissue damage in the contralateral limb by preventing fibrin deposition

As described above, we could not detect edema formation in the non-ischemic contralateral limb. Surprisingly, we could observe fibrin deposition in the contralateral leg (see Fig. 5). As observed in the lung (see Fig. 4A), we observed a significant inhibition of fibrin deposition in the non-ischemic limb by C1 INH (see Fig. 5). Complement deposition was inhibited by C1 INH in the contralateral limb, kidney and liver

The ischemic and the contralateral non-ischemic leg were analyzed for the deposition of complement fragments as markers for complement activation. As shown in Fig. 6A and B, C1 INH significantly reduced the deposition of C3b (classical and lectin pathway) as well as factor B (alternative pathway of complement activation) in the reperfused as well as in the contralateral leg. In addition treatment with C1 INH caused a significant reduction of C3b deposition in the kidney, and of factor B deposition in the liver.

Treatment with C1 INH preserved the endothelial glycocalyx in the

contralateral limb

Healthy EC are covered by a layer of glycosaminoglycans as e.g. heparan sulfate (HS), which is crucial for the anticoagulant and anti-inflammatory properties of the endothelium. HS are rapidly released under conditions of inflammation and tissue damage (1 1 -14). Surprisingly, C1 INH prevented shedding of HS in the contralateral limb (see Fig. 7). Inhibitory effect of C1INH on the inflammatory cytokine and chemokine network

Cytokines, growth factors as well as chemokines were measured using xMAP technology in EDTA-plasma taken at baseline, i.e. before induction of ischemia and at the endpoint after 24 h reperfusion. Analysis revealed C1 INH treatment significantly reduced the levels of IL-1 a, IL-4, IL-7, IL-17A and IL-18 as well as IFN- Y, MIP-1a, MIP-3a and TNF-a (see Table 3).

Table 3

Baseline Group NaCI Group C1 INH

Marker p-Value

(in pg/ml) (in pg/ml) (in pg/ml)

EPO 278.9 ± 183.2 729 ± 427.7 346.9 ± 353.1 n.s

GRO/KC 93.0 ± 14.491 127.4 ± 77.02 78.27 ± 68.79 n.s

IFN-Y 57.61 ± 34.88 120.3 ± 100.2 19.06 ±11.42 P < 0.05 ( ^* )

IL-1a 8.97 ±4.923 83.06 ± 44.86 16.85 ± 10.27 P < 0.05 ( ^* )

IL-4 22.62 ±11.40 57.52 ± 39.27 8.343 ± 4.209 P < 0.05 ( ^* )

IL-5 96.48 ±11.16 172.7 ±73.59 108.3 ±23.67 n.s

IL-7 69.05 ±22.87 240.9 ±98.34 67.21 ±42.01 P < 0.01 ( ^** )

IL-10 306.6 ±51.34 776.3 ± 508.0 279.1 ± 94.20 n.s

IL-17A 7.02 ±1.473 27.08 ± 13.97 8.267 ± 3.391 P < 0.05 ( ^* )

IL-18 1103 ±720.6 4155 ± 1390 1115 ±580.4 P < 0.01 ( ^** )

MCP-1 425 ± 57.98 1693 ±982.4 1905 ±638.3 n.s

MIP-1a 1097 ±968.0 4629 ± 3045 1203 ±762.0 P < 0.05 ( ^* )

MIP-3a 9.98 ±8.583 47.97 ± 20.24 12.02 ±9.502 P < 0.05 ( ^* )

RANTES 164 ±89.06 310.2 ±309.7 389 ± 442.7 n.s

TNF-a 19.12 ±6.099 40.38 ± 24.88 9.147 ± 7.453 P < 0.05 ( ^* )

VEGF 11.97 ±4.891 16.02 ±6.045 11.44 ±2.021 n.s

M-CSF 293.6 ± 50.83 381.2 ±117.1 459.1 ± 79.21 n.s Following cytokines could not be detected: ΙΙ_-1 β, IL-2, IL-6, IL-12p70, IL-13, G-CSF and GM-CSF. Data are expressed as means ± SD. Statistical significance was determined by Student ^' s t-test using the GraphPad Prism 5 software. P values of < 0.05 were considered statistically significant.

Effect of C1 INH treatment on apoptosis in lung and kidney cortex

Apoptosis was assessed using TUNEL assay. Cells in lung tissue of the vehicle- treated animals showed a high degree of apoptosis (76 + 21 %). In the cortex of kidneys, in proximal tubular epithelial cells, apoptosis was also observed in the vehicle-treated animals (43 + 25%). In comparison, C1 INH-treated animals showed a significant reduction in apoptotic cells (10 + 12% in lung (P<0.0001 ) and 7 + 8% in kidney cortex).

iii) Effects of FXII inhibitor rHA-lnfestin-4 on IRI-induced remote tissue and organ damage

Treatment with rHA-lnfestin-4 as described above also leads to a significant reduction in lung edema and potentially also reduces edema formation in other tissues.

In addition, a significant reduction in fibrin deposition in the lung (and potentially also in other tissues) is observed.

A significant reduction effect on apoptosis in lung and other tissues is observed after treatment with rHA-lnfestin-4. rHA-lnfestin-4 also leads to a reduction in the deposition of IgM and complement components, and potentially also shows an effect on the inflammatory cytokine and chemokine network. Reference List

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