Chinese scientists have developed and tested in pigs a bioadhesive hydrogel that promotes gastric ulcer healing through pH-independent and ultra-fast gelation, according to Science Translational Medicine. The gel can form even in an acidic environment and is retained on the ulcer site for at least 48 hours. Biologists believe that their development opens up new prospects in the treatment of gastrointestinal diseases, the therapy of which was difficult due to the harsh dynamic conditions of the gastrointestinal mucosa..

Hydrogels are widely used in medicine, including drug delivery and placement at the point of destination.. To enhance the interaction between tissue and hydrogel, its formation is often induced in situ, delivering the components needed for gel formation directly to the desired site.. However, this is not so easy to do in the stomach - the movement of the walls and constant secretion prevent the formation and retention of the gel on the ulcer, interfering with healing. This leads to a significant loss of both hydrogel mass and therapeutic load, thereby compromising the results of the entire treatment..

Therapeutic effects on the gastrointestinal tract are associated with a high risk of complications - some studies raise doubts about the safety of common drugs. A good alternative solution can be the development of a biomaterial that can be quickly formed and fixed in the harsh dynamic conditions of the stomach, but so far it has not been possible to find such an optimal method for treating gastroenterological diseases..

A group of scientists led by Xiayi Xu from the Chinese University of Hong Kong has created a hydrogel that, thanks to its easy endoscopic delivery and strong adhesion to ulcer tissues, offers an alternative to the usual gastroprotective treatment..

The authors decided to take as a basis catechol-based hydrogels, which firmly attach to both organic and inorganic surfaces by imitating a typical amino acid in the mussel leg protein. They are able to form quickly under alkaline conditions, however, when exposed to oxidants, their adhesion decreases.. But this effect, as it became known several years ago, can be combated with the help of the reducing thiourea group (NCSN). Researchers have synthesized polymer precursors by attaching catechol and thiourea groups to the hyaluronic acid backbone. To obtain the desired hydrogel, they sprayed an oxidizing agent over the solution, which was sodium peridiotate..

To test the effectiveness of the development, scientists artificially created stomach ulcers in pigs and randomly divided them into three groups: a control group, a group without a positive control treated with gastroprotective agents (sucralfate) and an experimental group exposed to a hydrogel.

Researchers have used endoscopic delivery of hydrogels to affected areas to quickly protect and further accelerate wound healing. An experimental group of pigs was induced to gel HA-Cat-NCSN in the stomach by delivering precursors and an oxidizer through separate catheters. After 48 hours, the experimental group was compared with the control group by immunohistochemical staining for inducible nitric oxide synthase, a marker of inflammation, the expression of which was less in those areas of the ulcer that were covered with hydrogel.

In the treatment group, sucralfate, wrapped in gauze, was injected through an endoscope and fixed at the site of the ulcer using endoscopic clamps. Follow-up was performed every week for a 14-day period to assess ulcer healing. On day 14, the pigs were sacrificed, the ulcer tissues were fixed with formalin for 24 hours, and then embedded in paraffin for blind histological analysis..

The ulcer index (product of the longest and shortest ulcer radii) in the experimental group was significantly lower than in the control and by 7 (P 0.05).

The formed hydrogel quickly adhered to the sites of gastric ulcer, providing a protective barrier for at least 48 hours, regardless of gastric motility, pH and harsh environment, which led to accelerated healing. Scientists also found that the hydrogel creates a protective barrier that prevents the penetration of external catabolic factors and the accumulation of growth factors around the ulcer area, which suppressed inflammation..

Biologists noticed that the therapeutic efficacy of sucralfate was achieved due to its precise delivery to the ulcer site, while typical oral administration cannot guarantee such? effective localization and, therefore, in reality, this method could give the worst therapeutic result. They believe that treatment with the developed hydrogel is, if not superior to, then certainly comparable to conventional drug treatments, and suggest that HA-Cat-NCSN will be a promising alternative for the treatment of refractory ulcers in clinical scenarios, and the possibility of its formation in situ provides greater control over.

Scientists have been trying to use hydrogels as a replacement for traditional therapeutic approaches for a long time.. Previously, for example, researchers at Ventrix reported on clinical trials of a porcine myocardial extracellular matrix hydrogel for the treatment of heart attacks. And about the use of hydrogels to simplify the study of processes inside organs and tissues, you can read here.

Vasilisa Raldugina https: // nplus1. ru /.

Keywords:.