Gut microbiota functions: metabolism of nutrients and other food components

The diverse microbial community that inhabits the human gut has an extensive metabolic repertoire that is distinct from, but complements the activity of mammalian enzymes in the liver and gut mucosa and includes functions essential for host digestion. As such, the gut microbiota is a key factor in shaping the biochemical profile of the diet and, therefore, its impact on host health and disease. The important role that the gut microbiota appears to play in human metabolism and health has stimulated research into the identification of specific microorganisms involved in different processes, and the elucidation of metabolic pathways, particularly those associated with metabolism of dietary components and some host-generated substances. In the first part of the review, we discuss the main gut microorganisms, particularly bacteria, and microbial pathways associated with the metabolism of dietary carbohydrates (to short chain fatty acids and gases), proteins, plant polyphenols, bile acids, and vitamins. The second part of the review focuses on the methodologies, existing and novel, that can be employed to explore gut microbial pathways of metabolism. These include mathematical models, omics techniques, isolated microbes, and enzyme assays

Post-colonoscopy appendicitis: A systematic review

Post-colonoscopy appendicitis is an infrequent complication of colonoscopy. This systematic review aimed to summarize the literature's current notions, clinical features, and management of post-colonoscopy appendicitis. PubMed and Embase were searched from inception until December 31, 2023. Two reviewers independently screened titles/abstracts and full-text papers for any study design about post-colonoscopy appendicitis and abstracted data. 56 articles with a total of 67 patients were included in the systematic review. The median age was 54.9 years (range 24–84), with more male individuals affected (64.2 %). The main indication of colonoscopy was investigation (37.3 %). Forty-three patients had colonoscopy with additional procedures (64.2 %). Most patients (79.1 %) presented with symptoms within two days after the colonoscopy. The clinical manifestation was the same as acute appendicitis. The diagnosis of post-colonoscopy appendicitis was confirmed in 70.2 % of the cases, mainly with abdominal computed tomography or, alternatively, ultrasound. Most patients were successfully treated with surgery (88.1 %), either open (56.8 %) or laparoscopic appendectomy (31.3 %). The conversion rate of laparoscopic appendectomy was 19.2 %. Non-operative management with intravenous antibiotics was attempted in 17 patients with a success rate of 41.2 %. Histopathology revealed acute appendicitis in 30 cases (44.8 %) and complicated appendicitis in 29 (49.2 %). Fecalith was found in 21 cases (31.3 %). Post-colonoscopy appendicitis is an infrequent but potential complication of colonoscopy. The onset of symptoms, especially pain, fever, nausea, and vomiting after a colonoscopy, should raise suspicion of this entity. A satisfactory outcome depends on timely diagnosis and appropriate management

Oral nicorandil recaptures the waned protection from preconditioning in vivo

1. Protection from preconditioning (PC) wanes and is eventually lost when multiple bouts of short ischemia or a prolonged reperfusion interval precedes the following sustained ischemia. The activation of mitochondrial K(ATP) channels plays a pivotal role in the intracellular signaling of PC. We tested whether the K(ATP) channel opener nicorandil (nic) preserves the given protection from PC in conditions where this benefit decays and is lost. 2. Eight groups of rabbits were divided into two equal series of experiments, one without nic (placebo) and one with nic treatment. Nic was given orally for 5 consecutive days in a dose of 5 mg kg(−1) d(−1). In a second step, four additional groups were treated with nic plus the K(ATP) channel blocker 5HD and 1 additional control group with nitroglycerin only. All the animals were anesthetized and then subjected to 30 min of myocardial ischemia and 2 h of reperfusion with one of the following interventions before the sustained ischemia: Control groups to no intervention; 3PC groups to three cycles of 5-min ischemia–10-min reperfusion; 8PC groups to eight cycles of 5-min ischemia – 10-min reperfusion; and 3PC90 groups to the same interventions as the 3PC groups but with a prolonged (90 min) intervening reperfusion interval before the sustained ischemia. The infarcted and the risk areas were expressed in percent. 3. There was no significant change in infarct size between the placebo, the nic and the 5HD-nic in the control groups (41.5±4.7, 43.9±7.1 and 48.7±6.4%) and 3PC groups (10.3±3.4, 12.2±3.9 and 12.6±4.5%). However, there was a significant decrease after nic treatment in groups 8PC (47.7±8.8% vs 13.0±2.6%, P<0.01) and 3PC90 (37.3±6.0% vs 14.2±2.4%, P<0.01), which was abrogated (38.2±4.7 and 42.7±4.4%, respectively, for 8PC and 3PC90 groups). Nitroglycerin had no effect on infarct size (39.1±3.1%, P=NS vs other controls). 4. Oral treatment with nic recaptures the waned protection of PC, both after repetitive bouts of short ischemia or after a prolonged reperfusion interval, preserving the initially obtained benefit. Nic by itself is insufficient to initiate PC in vivo