Said compositions can optionally comprise pharmacologically or biologically active substances. Said compositions comprising cells can be used for the reconstruction of the wall of the digestive apparatus Technical Background Therapy for gastric ulcers has long depended on H2 receptor antagonists such as cimetidine and ranitidine, able to inhibit gastric secretion.

Recently, drugs such as omeprazole which reduce the secretion of gastric acid by a specific mechanism of inhibition of the proton pump at a parietal cell level have been used.

Said drugs are often associated with antibiotics such as amoxacillin, tetracycline, metronidazole and claritromycin that are efficacious against Helicobacter pylori, the gram-negative micro-organism held to be responsible for the recurrence of peptic ulcers.

Surgery is resorted to only in the case of gastric ulcers, suspected to be malignant, or in cases of peptic ulcers complicated by stenosis impairing the passage of food. Cases of perforation also urgently require surgery to close the lesion and avoid potentially fatal consequences such as peritonitis.

Another pathology affecting the digestive system is diverticulitis of the oesophagus.

Diverticula of the digestive tract, particularly the oesophagus, are circumscribed, funnel-shaped or saccate extroversions, that may involve all the layers, or just the mucosa and submucosa of the gut wall.

Food residues stagnating in a diverticulum cause its inflammation, and may also find their way into the respiratory system as a result of coughing or regurgitation,

causing bronchitis, bronchial pneumonia and pulmonary abscesses ab ingestis.

Complications such as esophago-bronchial fistulae, oesophagitis, haemorrhages, malignant neoplasia of the diverticulum may also occur.

Treatment of the pathology, must include a suitable diet and the use of antispastic and prokinetic drugs, while more serious cases may require surgery.

Ulcers in the digestive tract may be caused not only by pathologies but also by external trauma, by swallowing sharp foreign bodies or caustic substances.

In the latter case, surgery may prove useless and the affected part may irretrievably lose its functions of absorption, secretion and peristalsis.

The role of hyaluronic acid, a natural polysaccharide, in the process of tissue repair has long been known (Weigel, P. H. et al.:"A model for the role of hyaluronic acid and fibrin in the early events during the inflammatory response and wound healing", J. Theor. Biol., 119: 219, 1986), especially in the early stages of granulation, as it stabilises the coagulation matrix and controls its degradation, favouring the recruitment of inflammatory cells such as polymorphonucleate leukocytes and monocytes, mesenchymal cells such as fibroblasts and endothelial cells, and, lastly, orienting subsequent migration of the epithelial cells.

For the above reasons, hyaluronic acid is widely used in pharmaceutical formulations in the form of creams, sprays and gauzes (Connettivina0) able to accelerate the healing of sores, wounds and burns (EP 0138572).

Moreover, hyaluronic acid derivatives (EP 0216453 B1) are known to be used as scaffolds for the culture of cells such as fibroblasts, keratinocytes, bone marrow stem cells (PCT WO 97/18842) to prepare grafts of bone tissue, cartilage and skin.

Lastly, there are known pharmaceutical preparations in the form of tablets or granules containing esters of acidic polysaccharides with choline (EP 0605478) with antiulcer properties at a gastric level due to their ability to form gels and protect the mucosa.

Although hyaluronic acid and its derivatives are used topically, their application in the digestive and gastrointestinal systems is as yet unknown.

It has now been discovered, surprisingly, that compositions based on hyaluronic

acid or its derivatives, optionally in association with growth factors or cell cultures, suitable for oral or endoscopic administration, can be used effectively in the treatment of lesions or ulcers in the digestive and gastrointestinal systems.

These are able to spread and adhere to the inner walls of the digestive apparatus, protecting the mucosa and stimulating tissue regeneration, possibly exercising an antibacterial activity if physically or chemically associated with substances having such properties.

In more serious cases, for example where there is loss or degeneration of a large area of tissue or perforation of the wall of the digestive apparatus, surgery can be performed and it is possible to reconstruct the injured part by grafting cell cultures grown on scaffolds constituted by hyaluronic acid derivatives.

Summary of the invention The Applicant has unexpectedly found that hyaluronic acid and derivatives thereof may be advantageously used in the treatment of ulcers, lesions and diverticula of the digestive and gastrointestinal apparatus.

The present invention therefore relates to the use of hyaluronic acid or a derivative thereof for the preparation of pharmaceutical compositions for the treatment of the above mentioned diseases.

Brief description of the drawings Figure 1 shows electron microscope image (Mag: 14.97 K X) on the 38'"day of culture grown on Petri dishes; Figure 2 shows electron microscope image (Mag: 17.50 K X) on the 38"day of culture grown on transwells; Figure 3 shows electron microscope image (Mag: 17.50 K X) on the 38t"day of culture grown on Laserskin (bidimensional matrix comprising hyaluronic acid esters); Figure 4 shows electron microscope image (Mag: 15.02 K X) on the 38t"day of culture grown on Hyaff11 3D (three-dimensional matrix comprising hyaluronic acid esters); Figure 4a shows electron microscope image (Mag: 898 X) on the 38t"day of culture grown on Hyaff11 3D (three-dimensional matrix comprising hyaluronic acid

esters); Figure 5 shows electron microscope image (Mag: 15.02 K X) on the 38"day of culture grown on polyurethane; Figure 6 shows diagrams with in ordinates ALP (alkaline phosphates) Activity (mU/mg of proteins) and in abscissae days of culture.

Detailed description of the invention Of the hyaluronic acid derivatives that can be used according to the present invention the following are to be preferred: - hyaluronic acid esters wherein part or all of the carboxy functions are esterified with alcohols of the aliphatic, aromatic, arylaliphatic, cycloaliphatic, heterocyclic series (EP 0216453 B1 entirely incorporated by reference); - autocross-linked esters of hyaluronic acid wherein part or all of the carboxy groups are esterified with the alcoholic functions of the same polysaccharide chain or other chains (EP 0341745 B1 entirely incorporated by reference); - cross-linked hyaluronic acid compounds wherein part or all of the carboxy groups are esterified with polyalcohols of the aliphatic, aromatic, arylaliphatic, cycloaliphatic or heterocyclic series, generating cross-linking by means of spacer chains (EP 0265116 B1 entirely incorporated by reference); - hemiesters of succinic acid or the heavy metal salts of the hemiester of succinic acid with hyaluronic acid or with partial or total esters of hyaluronic acid (WO 96/357207 entirely incorporated by reference); - 0-sulphated derivatives (WO 95/25751 entirely incorporated by reference) or N- sulphated derivatives (PCT/EP98/01973 entirely incorporated by reference); - amidic derivatives of hyaluronic acid or of the compounds listed above obtained by reaction of a primary or secondary amine of the aliphatic, aromatic, arylaliphatic, cycloaliphatic or heterocyclic series, that can optionally be a pharmaceutically active substance, with a free carboxylic group of hyaluronic acid or a derivative thereof; or by reaction of an acid of the aliphatic, aromatic, arylaliphatic or cycloaliphatic series, that can optionally be a pharmaceutically active substance, with a deacylated amino group of hyaluronic acid or a derivative thereof.

The compositions according to the present invention may also contain pharmacologically or biologically active substances such as antibiotics, in particular antibiotics active against Helicobacter pylori, growth factors, antimicotics, antimicrobials and antiviral agents. Compositions containing antibiotics active against Helicobacter pylori are for example in the form of mixtures or salts, or covalently bound with the aforesaid hyaluronic acid derivatives; heavy metal salts such as zinc and cobalt, salts of the hemiester of succinic acid or hyaluronic acid or with partial or total esters of hyaluronic acid.

The hyaluronic acid or hyaluronic acid derivatives used according to the present invention are preferably in the form of gels, guide channels, sponges, non-woven fabric, threads, continuous or perforated membranes, microspheres, nanospheres, gauzes or associations of the same.

In particular microspheres and nanospheres can be processed in the form of tablets, capsules, suspensions or solutions.

Therefore a further subject of the present invention relates to oral compositions suitable to be absorbed by the gastrointestinal mucose containing a hyaluronic acid derivative as the active ingredient for the treatment of ulcers, lesions and diverticula of the digestive and gastrointestinal apparatus.

The aforementioned active substances different from hyaluronic acid and the derivatives thereof may also be vehicled in hyaluronic acid and the derivatives thereof in the form of microspheres and nanospheres as disclosed respectively in EP A 517565 and WO 96/29998 Bidimensional or three dimensional matrix containing a hyaluronic acid derivative, may be used as support for cellular growth for the preparation of biological material containing suitable cell cultures for regenerating the walls or filling diverticula in the digestive apparatus. Said cells can be mature intestinal cells, mesenchymal cells, fibroblasts, epithelial cells or mixture thereof.

These biological materials for example may contain intestinal cells useful in the reconstruction of injured digestive apparatus. These biological materials are implanted onto the lesion site by surgical methods.

EXAMPLE Growth of epithelial cells on scaffolds made of benzyl esters of hyaluronic acid Intestinal cells were seeded onto scaffolds made of the total benzyl ester of hyaluronic acid in the form of a perforated membrane and non-woven fabric, in order to test their biocompatibility, and their morphological and biochemical responses were observed.

The cells belonged to the CaC02 cell line (derived from human colon carcinoma) that differentiate spontaneously into enterocytes typical of the mature intestinal epithelium.

The cells were used at passage 98. They were seeded at a density of about 9 x 103/cm2 in DMEM 4.5 g of glucose/L containing 20% FBS penicillin/streptomycin, fungizone and non-essential amino acids (1 %) in a humidified atmosphere with 95% C02. The culture medium was changed every 48 hours. Other cells were seeded on Petri dishes and Transwell wells with polycarbonate membranes in the same culture conditions and served as controls.

Polyurethane (chronoflex TM), a material for biomedical purposes, was used as negative control. On the 3 rd, 15 th, 20th and 40th days of culture, the cells were prepared for observation user scanning electron microscope (SEM) and for assessment of the total proteins and the activity of alkaline phosphates (ALP) according to the following methods: SEM fixing in 2.5% glutaraldehyde in phosphate buffer (PBS) pH 7.4. Osmium tetroxide, 1% in PBS, dehydration in ethanol and increasing concentrations of up to 100% and dehydration with a Critical Point drier. The cells were then metalized with gold and observed by SEM.

ALP activity: the cells were harvested by scraping in a lysis buffer 2mM Tris-HCI 50 mM mannitol pH 7.2 (1 ml final volume) (with the exception of those seeded on Hyaff 3D) and sonicated in ice. ALP activity of the cellular lysates was determined by spectrophotometry by hydrolysis of the p-nitrophenylphosphate using a Boehringer kit. The total proteins were determined by Lowry's method. The activity present in the cells grown on a scaffold in the form of a non-woven fabric was determined in lysates obtained by sonicating the membrane containing the cells in toto.

Morphological differentiation was assessed on the basis of the presence of microvilli on the upper surface of the cells, while the biochemical differentiation was assessed on the basis of the increase of ALP activity (see results in Figure 6).

Both were considered as biocompatibility parameters.

Figures 1,2, 3,4, 4a and 5 show electron microscope images of the cells on the 38t"day of culture, grown on Petri dishes, transwells, membranes of hyaluronic acid (Laserskin0), hyaluronic acid matrices (Hyaff11 3D) and polyurethane membranes respectively. As can be seen, the cells grown on Laserskin and Transwell show marked differentiation due to the appearance of numerous microvilli on their surfaces, whereas those grown on Petri dishes show fewer, less well developed microvilli. The cell grown on the scaffold (in the form of a non- woven fabric) and Chronoflex do not show any formation of microvilli, while those grown on Chronoflex alone present extroversion indicative of cell suffering.