Safety and Efficacy Study of Betaine Hydrochloride in Treating Hypergastrinemia in Patients With Autoimmune Gastritis

Autoimmune atrophic gastritis (AAG) is an organ-specific autoimmune disease that primarily affects the gastric body and fundus while sparing the antrum. Its characteristics include destruction of gastric wall cells, loss of intrinsic factors, and atrophy of the gastric mucosa. Endoscopic examination reveals features of reverse atrophy, with significant atrophy in the gastric body and fundus, appearing as a mosaic of red and white patches. Currently, AAG is believed to result from a pathological CD4+ T-cell-mediated autoimmune response against the gastric H+/K+-ATPase. CD4+ T lymphocytes target the parietal cells' H+/K+-ATPase, stimulating plasma cells to secrete autoantibodies, including parietal cell antibodies (PCA) and intrinsic factor antibodies (IFA). The former plays a key role in parietal cell destruction and glandular atrophy. AAG is considered a premalignant condition, with the potential development of gastric dysplasia, cancer, and type 1 gastric neuroendocrine tumours (type 1 g-NET). Gastric neuroendocrine tumors (g-NETs), also known as gastric carcinoids, account for approximately 23% of gastrointestinal and pancreatic neuroendocrine tumors. Clinically, g-NETs are mainly classified into three types. Type III is typically sporadic tumors associated with normal gastrin levels and poor prognosis. Although type 1 g-NETs caused by AAG are usually well-differentiated, studies have reported that 8%-23% of type 1 g-NETs extending into the deep submucosal layer may metastasize to regional lymph nodes or even to the liver. Furthermore, 3% of patients may develop neuroendocrine carcinoma, highlighting the need for appropriate attention. Due to the destruction of gastric glands (including parietal and chief cells) in AAG patients, there is a deficiency in intrinsic factor, gastric acid, and a decrease in pepsinogen I (PG-I) levels. Insufficient gastric acid secretion leads to a compensatory increase in gastrin secretion by G cells in the gastric antrum, which acts