Background of the Invention PCT/US03/13409 discloses invention based on the conception that nitric oxide (NO) level in blood provides a measure of tissue oxygenation and discloses a link between assessment of human condition and a therapeutic response.

Summary of the Invention It is now conceived that a. more accurate way of assessing human condition related to abnormality in tissue or blood oxygenation is based on the inability of red cells to properly cause vasodilation under hypoxic conditions and is by determining the extent to which blood sample causes dilation of blood vessels.

This method directly measures parameters that govern blood flow (and therefore tissue oxygenation) and is independent of NO in a cell that is not measurable.

In one embodiment, denoted the first embodiment, the invention is directed at a method of tracking the course of a disease in a patient where the disease associated with abnormality in tissue of blood oxygenation or impairment in the lungs ability to oxygenate blood and/or of determining the severity of said disease, comprising during the course of the disease, measuring the ability of blood sample from the patient to cause blood vessel dilation.

In another embodiment, denoted the second embodiment, the invention is directed to a method of treating a patient having a disease associated with abnormality in tissue or blood oxygenation or impairment in the lungs ability to oxygenate blood, comprising administering to the patient therapeutically effective amount of anaerobic solution of nitric oxide and/or therapeutically effective amount of solution of nitrite, nitrosothiol or alternative red blood cell loading agent (e. g. , ethyl nitrite) in response to measurement of ability of blood sample from the patient to cause blood vessel dilation showing lower than normal ability to cause blood vessel dilation.

In another embodiment, denoted the third embodiment, the invention is directed to a method of treating patient having a disease associated with abnormal red blood cell induced vasodilation, comprising administering to the patient a therapeutically effective amount of agent which causes increase in red blood cell induced vasodilation.

The term"disease associated with abnormality in tissue or blood oxygenation"is used herein to mean condition associated with impaired tissue oxygenation.

The term"disease associated with impairment of the lungs ability to oxygenate blood"is used herein to mean lung disease characterized by impaired v/p (i. e. , ventilation/perfusion) matching.

Detailed Description The diseases associated with abnormality in tissue or blood oxygenation or impairment in lungs ability to oxygenate blood are any diseases in which red blood cells from the patient do not properly dilate blood vessels within 10% of normal as determined, for example, by the test set forth hereinafter. These diseases include, for example, angina, heart failure, pulmonary hypertension, sickle cell disease, diabetes and stroke.

A test used for determining vasodilating ability involves use of descending rabbit thoracic aorta cut into 3 mm rings and mounted on stirrups at two grams tension attached to force transducers (model FT03, Grass Instruments, Quincy Mass). In an organ chamber the rabbit aortic rings have been pre-constricted with norepinephrine. Red cells sample (250 (J. 1 of 50% hematocrit) is added to organ chamber containing the pre-constricted aortic rings in oxygenated Kreb's buffer solution (1% oxygen) (25 cc). Relaxation of the pre-constricted aortic rings in terms of % of the pre-constricted tension caused by the red cells sample, is determined. The details of the bioassay are described in Stamler, J.. et al. , Proc. Natl. Acad. Sci. USA 89,444-448 (1992) and McMahon, T. , et al., Nature Medicine (2002), Vol 8,711-717.

When healthy red cells are added in the assay, 15 1.5% to 30 3.0% relaxation is obtained in the assay.

Below 15 zt 1.5% means defective tissue oxygenation.

A common type of response depending on the disease and severity thereof has been noted.

For sickle cell disease: When there is a vasocclusive crisis, the red cells from the patient cause further constriction rather than relaxation. When the patient has modest pain, the percent relaxation might be about 10%. When a sickle cell patient feels generally good, the patient's red cells cannot be distinguished from normal red blood cells in the bioassay.

In determination of the course of a disease, a plurality of measurements are carried out over time, e. g. , once a month, and the results from the patient's red blood cells, while the patient is feeling good, serve as a base line. Over time, <BR> <BR> decrease in percent relaxation, e. g. , from 15% to 10% or from 10% to 5% means the patient is getting worse while increase in percent relaxation means the patient is getting better.

A single measurement is useful to determine severity of disease, e. g. , extent of percent relaxation less than 15%.

The method constitutes a non-invasive measurement of oxygen delivery to tissue and of how well the patient is feeling.

We turn now to the second embodiment herein. The measurement of the ability of blood sample from the patient to cause blood vessel dilation constitutes a measurement of the first embodiment herein. The treatments herein of nitric oxide and/or nitrite administration are carried out in the general amounts and with the routes of administration described for the second, third and fourth embodiments of PCT/US03/13409 with a therapeutically effective amount being an amount that increases relaxation percentage in the bioassay described above. Administration of nitrosothiols, e. g. , nitrosoglutathione, or alternative red cell loading agent (e. g., ethyl nitrite) can be carried out, e. g. , by infusion to establish a blood concentration ranging from 1 nanomolar to 10 millimolar depending on the drug amount. A therapeutically effective amount is an amount that increases relaxation percentage in the bioassay described above or alternative assay with the same function.

We turn now to the third embodiment herein.

The determination of disease associated with abnormal red blood cell induced vasodilation is readily determined by measurement of the ability of a blood sample from a patient to cause blood vessel dilation as carried out in the first embodiment herein. The diseases associated with abnormal red blood cell induced vasodilation include those recited above in the description of the first embodiment.

For the third embodiment, any agent which causes increase in red blood cell induced vasodilation can be administered. These include the agent administered for the second embodiment as well as statins and ACE inhibitors, administered, for example, in dosages and with routes of administration as are known for use with a particular statin or ACE inhibitor.

It is apparent that average relaxation in a bioassay for ability to cause blood vessel dilation will depend on degree of tone, buffer and related conditions and that the means of relaxation can be different under these different conditions, i. e., the average characteristic can be individualized to the bioassay so that what is 15% in the described bioassay may be 10% in another bioassay or 30% in a third bioassay but the principle of different degrees in the bioassays as a function of disease holds.

In addition, one can alternatively assay ability of blood sample from a patient to cause blood vessel relaxation as a graded response across a range of PO2s ranging from 60 to 0 mm Hg as described in MacMahon et al cited above. The average PO2 at which red cells switch from constriction effect to dilation effect is about 10 mm Hg in the normal red cell. More vigorous (healthy) vasodilation implies that the switch occurs at higher PO2 whereas dysfunctional red cells switch at lower P02.

The invention is illustrated by the following working examples.

Example I A patient has a history of sickle cell disease. In month one, when the patient is feeling good, measurement of ability of a blood sample from the patient shows 20% relaxation in the above-described bioassay. In month six, a blood sample from the patient shows 10% relaxation. The patient has hypoxia and modest pain. Infusion at a rate of 5 nmol/min of NO in 0.9% NaCI is effected.

Pain resolves. Blood sample causes 15% relaxation. In month 12, a blood sample from the patient causes constriction. The patient is in vasocclusion crisis. Infusion of NO as above together with nitrite at a rate of 10 nmol/min results in decrease in pain and blood sample causes 10% relaxation.

Example II A 65-year old male is admitted to a hospital with unstable angina. The patient is given I. V. nitroglycerin, heparin and a beta blocker. However, the patient continues to experience chest pain at rest. The patient's normal blood sample caused vasodilation is known from past testing. Measurement of the patient's blood sample caused vasodilation shows the percent relaxation is below normal.

Alternatively, the patient's normal percent relaxation is not known from past testing but measurement of the patient's percent relaxation shows it is lower than average. Infusion at a rate of 5 nmol/min of NO in 0.9% NaCI is effected. The chest pain resolves.

When nitrite is additionally given at a rate of 100 nmol/min, the chest pain resolves more quickly.

Example III A 27-year old female with primary pulmonary hypertension class II presents complaining with shortness of breath. The patient's normal blood sample caused percent relaxation is known from prior testing. Measurement of the patient's blood sample caused percent relaxation shows it is below normal. Infusion of NO in 0.9% NaCI at a rate of 5 nmol/min of NO is effected. The shortness of breath symptom resolves. After three days of therapy, pulmonary artery pressure drops 5mm of mercury.

Example IV A 40-year old with diabetes presents with poor peripheral perfusion and leg pain. Red blood cells only dilate blood vessels at low PO2. Infusion of S- nitrosoglutathione at 1 nmol/kg/min corrects the defect and improves perfusion.

Example V A 70-year old with heart failure and pulmonary hypertension has defective red blood cells induced vasodilation in a bioassay. Infusion of NO at 1 nmol/kg/min improves dyspnea.

Example VI An 80-year old with a stroke shows increasing cognitive dysfunction. His red blood cells are found to constrict blood vessels in a bioassay. Infusion of NO improves red blood cell vasodilation and cognition.

Example VII A 20-year old with sickle cell disease and acute painful crisis has red blood cell vasodilation dysfunction. Lipitor is initiated. Over the following 24 hours, red blood cell vasodilation function normalizes, and the patient is symptomatically improved.

Variations Many variations of the above will be obvious to those skilled in the art.

Thus, the invention is defined by the claims.