The effects of branched-chain amino acids on muscle protein synthesis, muscle protein breakdown and associated molecular signalling responses in humans: an update.

Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are three of the nine indispensable amino acids, and are frequently consumed as a dietary supplement by athletes and recreationally active individuals alike. The popularity of BCAA supplements is largely predicated on the notion that they can stimulate rates of muscle protein synthesis (MPS) and suppress rates of muscle protein breakdown (MPB), the combination of which promotes a net anabolic response in skeletal muscle. To date, several studies have shown that BCAA (particularly leucine) increase the phosphorylation status of key proteins within the mechanistic target of rapamycin (mTOR) signalling pathway involved in the regulation of translation initiation in human muscle. Early research in humans demonstrated that BCAA provision reduced indices of whole-body protein breakdown and MPB; however, there was no stimulatory effect of BCAA on MPS. In contrast, recent work has demonstrated that BCAA intake can stimulate postprandial MPS rates at rest and can further increase MPS rates during recovery after a bout of resistance exercise. The purpose of this evidence-based narrative review is to critically appraise the available research pertaining to studies examining the effects of BCAA on MPS, MPB and associated molecular signalling responses in humans. Overall, BCAA can activate molecular pathways that regulate translation initiation, reduce indices of whole-body and MPB, and transiently stimulate MPS rates. However, the stimulatory effect of BCAA on MPS rates is less than the response observed following ingestion of a complete protein source providing the full complement of indispensable amino acids.

Metabolomic profile of combined healthy lifestyle behaviours in humans: A systematic review.

A combination of healthy lifestyle behaviours (i.e., regular physical activity, nutritious diet, no smoking, moderate alcohol, and healthy body mass) has been consistently associated with beneficial health outcomes including reduced risk of cardiometabolic diseases. Metabolomic profiles, characterized by distinct sets of biomarkers, have been described for healthy lifestyle behaviours individually and in combination. However, recent literature calls for systematic evaluation of these heterogenous data to identify potential clinical biomarkers relating to a combined healthy lifestyle. The objective was to systematically review existing literature on the metabolomic profile of combined healthy lifestyle behaviours. MEDLINE, EMBASE and Cochrane databases were searched through March 2022. Studies in humans outlining the metabolomic profile of a combination of two or more healthy lifestyle behaviours were included. Collectively, the metabolomic profile following regular adherence to combined healthy lifestyle behaviours points to a positive association with beneficial fatty acids and phosphocreatine, and inverse associations with triglycerides, trimethylamine N-oxide, and acylcarnitines. The findings suggest that a unique metabolomic profile is associated with combined healthy lifestyle behaviours. Additional research is warranted to further describe this metabolomic profile using targeted and untargeted metabolomic approaches along with uniform definitions of combined healthy lifestyle variables across populations.

An assessment of the yield of EUS in patients referred for dilated common bile duct and normal liver function tests.

OBJECTIVE: This study aims to determine the yield of EUS in patients with common bile duct (CBD) dilation and normal liver function tests (LFTs). MATERIALS AND METHODS: Between October 2000 and December 2016, all patients referred for EUS for unexplained CBD dilatation (CBD ≥7 mm), with normal aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and bilirubin and no history of sphincterotomy, were eligible. Linear-array EUS was performed by one of the two experienced endosonographers. Data were extracted from a prospectively maintained database. RESULTS: Of 29,920 upper gastrointestinal EUS procedures performed, 840/29,920 (3%) were for unexplained CBD dilation. Of 840 patients, 199 (24%) had normal LFTs, 99% were Caucasian, 46% had biliary-type abdominal pain, and 41% were postcholecystectomy. EUS diagnosed choledocholithiasis (CDL) or sludge in 18/199 (9%) patients (7/18 had CBD sludge only). No other pathology was diagnosed. Of 18 CDL patients, 15 (83%) had an intact gallbladder, and all 15 patients had cholelithiasis. The frequency of CDL or sludge in postcholecystectomy patients was only 3.7% (3/82); none of these patients were younger than 69 years of age. Regression analyses showed no associations between EUS diagnosis of CDL or sludge and biliary-type abdominal pain, other symptoms, sex, or race. Each additional year of age was associated with an increase in the risk of CDL or sludge by a factor of 1.05 (odds ratio: 1.05; P = 0.034). SUMMARY: In patients with CBD dilation and normal LFTs, the only significant pathology identified is CBD stones or sludge (almost exclusively in elderly patients with cholelithiasis). CONCLUSION: EUS should be avoided in patients with dilated bile ducts and normal LFTs, especially if under 65 years of age and postcholecystectomy.