Update on gut microbiota in gastrointestinal diseases.

The human gut is a complex microbial ecosystem comprising approximately 100 trillion microbes collectively known as the "gut microbiota". At a rough estimate, the human gut microbiome contains almost 3.3 million genes, which are about 150 times more than the total human genes present in the human genome. The vast amount of genetic information produces various enzymes and physiologically active substances. Thus, the gut microbiota contributes to the maintenance of host health; however, when healthy microbial composition is perturbed, a condition termed "dysbiosis", the altered gut microbiota can trigger the development of various gastrointestinal diseases. The gut microbiota has consequently become an extremely important research area in gastroenterology. It is also expected that the results of research into the gut microbiota will be applied to the prevention and treatment of human gastrointestinal diseases. A randomized controlled trial conducted by a Dutch research group in 2013 showed the positive effect of fecal microbiota transplantation (FMT) on recurrent Clostridioides difficile infection (CDI). These findings have led to the development of treatments targeting the gut microbiota, such as probiotics and FMT for inflammatory bowel diseases (IBD) and other diseases. This review focuses on the association of the gut microbiota with human gastrointestinal diseases, including CDI, IBD, and irritable bowel syndrome. We also summarize the therapeutic options for targeting the altered gut microbiota, such as probiotics and FMT.

Gurvits syndrome: a case of acute esophageal necrosis associated with diabetic ketoacidosis.

BACKGROUND: Acute esophageal necrosis (AEN), commonly referred to as Gurvits syndrome or "black esophagus", is a rare clinical disease. We present a case of AEN associated with diabetic ketoacidosis (DKA). CASE PRESENTATION: A 66-year-old male came to our hospital with coffee-ground emesis, dyspnea, and general malaise. He was treated for type 2 diabetes mellitus using insulin and had not been taking his medication, including insulin, for several days. Laboratory analysis revealed severe hyperglycemia (730 mg/dL), normocytic anemia (hemoglobin level, 7.7 g/dL; mean corpuscular volume, 100.4 fL), high serum potassium (7.6 mEq/L), and a high level of blood urea (98.7 mg/dL). Ketones and glucose were detected in the urine, and serum ß-hydroxybutyrate was elevated (2132 µmol/L). Arterial blood gas analysis confirmed metabolic acidosis (pH, 7.29; HCO3, 10.5 mmol/L). Collectively, the patient was diagnosed with DKA and upper gastrointestinal bleeding. The patient's condition improved with intravenous fluids, and he received intravenous insulin to treat DKA. According to these findings, the patient was diagnosed with DKA and upper gastrointestinal bleeding. The patient underwent esophagogastroduodenoscopy (EGD) which revealed a circumferential necrosis of the middle and distal esophagus, immediately proximal to the gastroesophageal junction. The patient was then treated with an intravenous proton pump inhibitor. The patient continued to improve with conservative treatment and was subsequently discharged in a stable condition. An EGD repeated 14 days after discharge showed complete healing of the necrotic-like mucosal change without stricture formation of the esophagus. CONCLUSIONS: AEN is rare but potentially life-threatening case of upper gastrointestinal bleeding. Therefore, a clinician should be aware of AEN as a potential cause of upper gastrointestinal bleeding in elderly patients with poorly controlled diabetes and significant comorbidities.

Can control of gut microbiota be a future therapeutic option for inflammatory bowel disease?

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract encompassing two main clinical entities, Crohn's disease and ulcerative colitis. Accumulated evidence indicates that an aberrant immune activation caused by the interplay of genetic susceptibility and environmental impact on the gut microbiota may be involved in the pathogenesis of IBD. Rapid advances in next-generation sequencing technology have enabled a number of studies to identify the alteration of the gut microbiota, termed dysbiosis, in IBD. Moreover, the alteration in the metabolites derived from the gut microbiota in IBD has also been described in many studies. Therefore, microbiota-based interventions such as fecal microbiota transplantation (FMT) have attracted attention as a novel therapeutic option in IBD. However, in clinical trials, the efficacy of FMT for IBD remains controversial. Additional basic and clinical studies are required to validate whether FMT can assume a complementary role in the treatment of IBD. The present review provides a synopsis on dysbiosis in IBD and on the association between the gut microbiota and the pathogenesis of IBD. In addition, we summarize the use of probiotics in IBD and the results of current clinical trials of FMT for IBD.