Background Skeletal muscle loss (sarcopenia) is a major clinical complication in alcoholic cirrhosis with no effective therapy. Skeletal muscle autophagic proteolysis and myostatin expression (inhibitor of protein synthesis) are increased in cirrhosis and believed to contribute to anabolic resistance. A prospective study was performed to determine the mechanisms of sarcopenia in alcoholic cirrhosis and potential reversal by leucine. Methods In 6 well-compensated, stable alcoholic cirrhotic patients and 8 controls, serial vastus lateralis muscle biopsies were obtained before and 7h after a single oral BCAA mixture enriched with leucine (BCAA/LEU). Primed-constant infusion of L-[ring-2H5]-phenylalanine was used to quantify whole body protein breakdown (WbPB) and muscle protein fractional synthesis rate (FSR) using liquid chromatography/mass spectrometry. Muscle expression of myostatin, mTOR targets, autophagy markers, protein ubiquitination and intracellular amino acid deficiency sensor, general control of nutrition 2 (GCN2) were quantified by immunoblots and leucine transporter (SLC7A5) and glutamine exchanger (SLC38A2) by real time PCR. Results Following oral administration, plasma BCAA concentrations showed a similar increase in cirrhosis and controls. Skeletal muscle FSR was 9.63±0.36%/h in controls and 9.05±0.68%/h in cirrhotics (p=0.54). Elevated WbPB in cirrhosis was reduced with BCAA/LEU (p=0.01). Fasting skeletal muscle molecular markers showed increased myostatin expression, impaired mTOR signaling and increased autophagy in cirrhosis compared to controls (p<0.01). BCAA/LEU did not alter myostatin expression but mTOR signaling, autophagy measures and GCN2 activation were consistently reversed in cirrhotic muscle (p<0.01). SLC7A5 expression was higher in basal state in cirrhosis than controls (p<0.05) but increased with BCAA/LEU only in controls (p<0.001). Conclusions We demonstrate that impaired mTOR1 signaling and increased autophagy in skeletal muscle of alcoholic cirrhosis patients is acutely reversed by BCAA/LEU.

The present study concentrates on the evaluation of the anti-glycation effect of some bioactive substances present in yerba maté (Ilex paraguariensis): 5-caffeoylquinic acid, caffeic acid and a sapogenin (oleanolic acid). Bovine serum albumin and histones were incubated in the presence of methylglyoxal with or without the addition of 5-caffeoylquinic acid, caffeic acid and oleanolic acid. After the incubation period, advanced glycation end product (AGE) fluorescence spectra were performed and protein structural changes were evaluated by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis. Chlorogenic acid, caffeic acid are the main substances responsible for the anti-glycation effect of maté tea.

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A rise in postprandial serum triglycerides (PP-sTG) can potentiate inflammatory responses in vascular endothelial cells (ECs) and thus serves as an independent risk factor for predicting increased cardiovascular morbidity. We examined postprandial triglyceride-rich lipoproteins (PP-TGRLs) in subjects ranging from normal to hypertriglyceridemic for their capacity to alter EC acute inflammatory responses. Cultured human aortic ECs (HAECs) were conditioned with PP-TGRLs isolated from human serum at the peak after a moderately high-fat meal. VLDL particle size increased postprandially and varied directly with the subject's PP-sTG level and waist circumference. PP-TGRL particles bound to HAECs and were internalized via LDL receptor-mediated endocytosis. PP-TGRL alone did not induce an inflammatory response over the range of individuals studied. However, combined with low-dose TNF-α stimulation (0.3 ng/ml), it elicited a net 10-15% increase above cytokine alone in the membrane expression of VCAM-1, ICAM-1, and E-selectin, which was not observed with fasting TGRLs. In contrast to upregulation of ICAM-1 and E-selectin, VCAM-1 transcription and expression varied in direct proportion with individual PP-sTG and waist circumference. The extent of monocyte arrest on inflamed HAECs under shear stress also correlated closely with VCAM-1 expression induced by conditioning with PP-TGRL and TNF-α stimulation. This ex vivo approach provides a quantitative means to assess an individual's inflammatory potential, revealing a greater propensity for endothelial inflammation in hypertriglyceridemic individuals with abdominal obesity.

APR2 is the dominant APR (adenosine 5'-phosphosulfate reductase) in the model plant Arabidopsis thaliana, and converts activated sulfate to sulfite, a key reaction in the sulfate reduction pathway. To determine whether APR2 has a role in selenium tolerance and metabolism, a mutant Arabidopsis line (apr2-1) was studied. apr2-1 plants had decreased selenate tolerance and photosynthetic efficiency. Sulfur metabolism was perturbed in apr2-1 plants grown on selenate, as observed by an increase in total sulfur and sulfate, and a 2-fold decrease in glutathione concentration. The altered sulfur metabolism in apr2-1 grown on selenate did not reflect typical sulfate starvation, as cysteine and methionine levels were increased. Knockout of APR2 also increased the accumulation of total selenium and selenate. However, the accumulation of selenite and selenium incorporation in protein was lower in apr2-1 mutants. Decreased incorporation of selenium in protein is typically associated with increased selenium tolerance in plants. However, because the apr2-1 mutant exhibited decreased tolerance to selenate, we propose that selenium toxicity can also be caused by selenate's disruption of glutathione biosynthesis leading to enhanced levels of damaging ROS (reactive oxygen species).

Paraoxonase 1 (PON-1), an antioxidant enzyme carried mainly by HDL, has been shown to display cardioprotective effects. In this study, we investigated whether the polyphenol-rich beverage mate, obtained from extract of Ilex paraguariensis (IP), prevented the loss of PON-1 activity from HDL during oxidant stress. The peroxide radical generator 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH) induced time- and dose-dependent oxidation of HDL, as measured by lipoperoxide content, which is accompanied by a parallel decrease in the activity of PON-1 (p<0.001). IP extract (2-20 microL/mL) afforded time- and concentration-dependent inhibition of the oxidation, with preservation of apoA-I structure and PON-1 activity. Healthy volunteers drank either 0.5 L of IP extract, 0.5 L of coffee and milk or nothing. PON-1 activity increased an average of 10% above the changes seen when the intake was coffee and milk (p<0.05). In conclusion, we demonstrate that IP extract may, to some extent, prevent the loss of the antiatherogenic function of HDL afforded by PON-1 when the particle is under oxidant stress.

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Drug induced Long QT syndrome results primarily from block of the cardiac potassium channel heRG (human-ether-a-gogo related gene). In some cases prolongation of the QT interval can result in the lethal arrhythmia torsade de pointes, an arrhythmia characterized by a rapid heart rate and severely compromised cardiac output. Many patients requiring medication present with abnormal serum electrolyte levels due to a variety of conditions including gastrointestinal dysfunction, renal and endocrine disorders, diuretic use, alcoholism and aging. Extracellular cations have significant influence on HERG channel gating and in some instances they have been shown to alter drug block of heRG. however, the mechanisms by which drug block is altered in different extracellular cation solutions are not well understood. In this study, heRG block by quinidine and cisapride was assessed in extracellular solutions of calcium, potassium, rubidium, cesium and tetraethylammonium (TeA) using two-electrode voltage clamping of Xenopus oocytes. Consistent with previous reports we show that increases in extracellular potassium reduce heRG block by quinidine and cisapride. We also show that increasing extracellular rubidium and cesium reduced heRG block by quinidine and cisapride whereas increasing extracellular calcium and extracellular TeA did not alter heRG block by quinidine and cisapride. These results demonstrate that at lower extracellular potassium concentrations, the permeant ion is almost exclusively responsible for the reduction in quinidine and cisapride block of heRG due to increases in extracellular potassium.