Gut production of GABA by a probiotic formula: an in vitro study.

The objective of this study was to evaluate the influence of a probiotic formula on the production of neuroactive compounds in different parts of the colon in batch culture and in vitro gut simulator experiments. Thirteen lactic acid bacterial strains, belonging to the species Levilactobacillus brevis, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Ligilactobacillus salivarius, Streptococcus thermophilus, were characterised for their in vitro ability to produce neurotransmitters. L. brevis P30021 and L. plantarum P30025 were selected based on their capability to produce γ-aminobutyric acid (GABA) and acetylcholine in vitro. A probiotic formulation with potential psychobiotic activity was prepared and tested in a batch culture of human microbiota monitoring the formation of GABA and acetylcholine. Samples of the three colonic tracts were taken from the Simulator of the Human Intestinal Microbiota (SHIME®) evaluating the production of GABA and other neurotransmitters by LC-MS. Short chain fatty acids (SCFA) by GC and microbiota composition by 16S rRNA gene sequencing were also determined. Probiotic supplementation led to the formation of GABA and acetylcholine with a decrease in glutamate concentrations in the in vitro batch fermentation. Production of GABA after the treatment with probiotics was confirmed in the SHIME® short-term experiment. No differences in short-chain fatty acids were observed up to 72 h of fermentation. Different microbiota composition was found in the three different parts of the colon, with a higher abundance of Veillonellaceae in the ascending colon vessels. The probiotic-exposed microbiota showed higher levels of Bacteroides, a gut microbe associated with anti-inflammatory activities and a potential GABA producer. Results demonstrate the impact of the tested probiotic formula on gut microbiota structure and GABA production. In conclusion, the probiotic treatment changed the microbiota composition and increased neuroactive metabolites production, indicating promising potential as psychobiotics, even if further clinical evidence is needed to confirm the effectiveness of these probiotics in improving mental health.

Post-surgical deep vein thrombosis prevention: evaluation of the risk/benefit ratio of fractionated and unfractionated heparin.

An open controlled study was carried out to assess the efficacy and tolerance of a new low molecular weight heparin for the prevention of post-surgical deep vein thrombosis and pulmonary embolism. Forty-five patients undergoing abdominal surgery mainly for neoplasm, gallstones and gastric ulcers were administered 7,500 AXaU of low molecular weight heparin subcutaneously, 2 hours before surgery and once a day for 7 days after. Heparin calcium (15,000 IU subcutaneously per day) was used as a comparison drug in 45 control subjects, matched for age, sex and type of operation. Deep vein thrombosis was identified with clinical parameters, radio-labelled fibrinogen uptake test, echo-doppler and venography; pulmonary embolism with clinical examination, chest X-rays and/or scintigraphy. No episodes of deep vein thrombosis occurred in the low molecular weight heparin-treated patients, whilst there was 1 episode, without pulmonary embolism, in the control group. The consumption of blood and haemoderivatives for transfusions was higher in the heparin calcium group. Only in this group, furthermore, did 5 patients have to suspend antithrombotic treatment due to severe haemorrhages. General tolerance of the two drugs was identical and very good.

Clinical significance of serum pancreatic enzymes in the quiescent phase of chronic pancreatitis.

The most commonly used serum enzymes in pancreatic diseases are total amylase, pancreatic isoamylase, lipase and trypsin. To determine which of these enzymes is the most useful in the diagnosis of clinically quiescent chronic pancreatitis and which enzyme best reflects exocrine functional reserve, we studied 22 healthy control subjects, 44 patients with gastrointestinal, liver and biliary tract diseases, and 25 patients with chronic pancreatitis. On the basis of duodenal intubation, the latter were divided into two subgroups: one group of 13 patients with slight to moderate secretion deficiency and another of 12 patients with severe exocrine insufficiency. Of the enzymes studied, lipase, trypsin and pancreatic isoamylase are equally suitable for the evaluation of function in severe chronic pancreatitis, but not for the early diagnosis of the disease. Results for total amylase are not reliable so that its use in the study of chronic pancreatitis is not advisable.