Identification of a Circulating Amino Acid Signature in Frail Older Persons with Type 2 Diabetes Mellitus: Results from the Metabofrail Study.

Diabetes and frailty are highly prevalent conditions that impact the health status of older adults. Perturbations in protein/amino acid metabolism are associated with both functional impairment and type 2 diabetes mellitus (T2DM). In the present study, we compared the concentrations of a panel of circulating 37 amino acids and derivatives between frail/pre-frail older adults with T2DM and robust non-diabetic controls. Sixty-six functionally impaired older persons aged 70+ with T2DM and 30 age and sex-matched controls were included in the analysis. We applied a partial least squares-discriminant analysis (PLS-DA)-based analytical strategy to characterize the metabotype of study participants. The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 94.1 ± 1.9% for frail/pre-frail persons with T2DM and 100% for control participants. Functionally impaired older persons with T2DM showed higher levels of 3-methyl histidine, alanine, arginine, glutamic acid, ethanolamine sarcosine, and tryptophan. Control participants had higher levels of ornithine and taurine. These findings indicate that a specific profile of amino acids and derivatives characterizes pre-frail/frail older persons with T2DM. The dissection of these pathways may provide novel insights into the metabolic perturbations involved in the disabling cascade in older persons with T2DM.

Major liver resection results in a changed plasma amino acid pattern as reflected by a decreased Fischer ratio which improves by bactericidal/permeability increasing protein.

BACKGROUND/AIMS: Major liver resection results in a high morbidity and mortality, and endotoxin plays a role in post-resection hepatic failure. Severe hepatic failure as seen in hepatitis and cirrhosis may be accompanied by hepatic encephalopathy and is characterized by a typical plasma amino acid pattern reflected by a decreased Fischer ratio. This study was performed to evaluate the plasma amino acid pattern in patients undergoing major liver surgery receiving placebo or the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21). PATIENTS AND METHODS: Forty-eight patients were randomized in this phase II, dose escalation, multicenter trial. Plasma amino acid profiles were determined preoperatively, and on the first (day 1) and third (day 3) postoperative day. RESULTS: In the placebo group the Fischer ratio decreased significantly on both postoperative days. Administration of rBPI21 also resulted in a decreased Fischer ratio on day 1, but not on day 3. Highly elevated alanine plasma levels were observed on day 1 in placebo-treated patients, whereas rBPI21 prevented this elevation. Plasma alanine levels on day 1 correlated with the duration of post-resection hepatic failure. CONCLUSIONS: Major liver resection results in a decreased Fischer ratio and a rise in plasma alanine levels. Plasma levels of alanine on the first postoperative day correlated with the duration of the post-resection hepatic failure. rBPI21 improved the Fischer ratio and prevented the rise of plasma alanine levels.

A novel stable reproducible model of hepatic failure in canines.

BACKGROUND: Stable and reproducible large animal models of hepatic failure, which allow the assessment of liver-assist devices, are not available. Our objective was to develop a physiologically stable animal model of hepatic failure on which the safety and efficacy of an extracorporeal liver-assist device can be tested. We hypothesized that a surgical model which consists of an end-to-side portocaval shunt combined with common bile duct ligation and transection would create hepatic failure with: (1) elevations in amino transferases, total bilirubin, and ammonia; (2) a decrease in the ratio of branched chain to aromatic amino acids; and (3) histologic evidence of hepatic injury. METHODS: Eleven mongrel dogs underwent common bile duct transection and an end-to-side portocaval shunt. Aminotransferases (AST, ALT), total bilirubin, ammonia, and branched chain and aromatic amino acids were measured prior to operation (baseline) and after 9 days. A necropsy was performed on Postoperative Day 9 and liver biopsies were obtained for histology. RESULTS: By Postoperative Day 9, AST, ALT, total bilirubin, and ammonia values were significantly elevated compared to baseline (P < 0.02). The ratio of branched chain to aromatic amino acids was significantly reduced compared to baseline (P < 0.003). There was histologic evidence of cholestasis and inflammation. CONCLUSION: Portocaval shunt with common bile duct transection produces liver failure with elevations in aminotransferases, total bilirubin, and ammonia, a decreased branched chain to aromatic amino acid ratio, and histologic inflammation. Unlike ischemic or chemically induced models of liver failure, the dogs were hemodynamically and neurologically stable. This model can be used to test the safety and efficacy of liver-assist devices aimed at temporizing the detoxification functions of the failing liver.