Noninvasive monitoring of fibre fermentation in healthy volunteers by analyzing breath volatile metabolites: lessons from the FiberTAG intervention study.

The fermentation of dietary fibre (DF) leads to the production of bioactive metabolites, the most volatile ones being excreted in the breath. The aim of this study was to analyze the profile of exhaled breath volatile metabolites (BVM) and gastrointestinal symptoms in healthy volunteers after a single ingestion of maltodextrin (placebo) versus chitin-glucan (CG), an insoluble DF previously shown to be fermented into short-chain fatty acids (SCFA) by the human microbiota in vitro. Maltodextrin (4.

Studying the Role of AMPK in Cardiac Hypertrophy and Protein Synthesis.

Pathological cardiac hypertrophy, which is a compensatory mechanism established to maintain cardiac function in response to neurohormonal or mechanical stresses, becomes maladaptive with time and frequently leads to heart failure. AMP-activated protein kinase (AMPK) has been extensively described in the literature to act as a break in cardiac hypertrophy development. Its anti-hypertrophic action mostly correlates with the inhibition of several important players of cardiac hypertrophy including protein synthesis and pro-hypertrophic gene expression pathways involving the transcription factor nuclear factor of activated T cells (NFAT) and the mitogen-activated protein kinases ERK1/2.

AMPK activation counteracts cardiac hypertrophy by reducing O-GlcNAcylation.

AMP-activated protein kinase (AMPK) has been shown to inhibit cardiac hypertrophy. Here, we show that submaximal AMPK activation blocks cardiomyocyte hypertrophy without affecting downstream targets previously suggested to be involved, such as p70 ribosomal S6 protein kinase, calcineurin/nuclear factor of activated T cells (NFAT) and extracellular signal-regulated kinases. Instead, cardiomyocyte hypertrophy is accompanied by increased protein O-GlcNAcylation, which is reversed by AMPK activation.

O-GlcNAcylation, enemy or ally during cardiac hypertrophy development?

O-linked attachment of the monosaccharide β-N-acetyl-glucosamine (O-GlcNAcylation) is a post-translational modification occurring on serine and threonine residues, which is evolving as an important mechanism for the regulation of various cellular processes. The present review will, first, provide a general background on the molecular regulation of protein O-GlcNAcylation and will summarize the role of this post-translational modification in various acute cardiac pathologies including ischemia-reperfusion. Then, we will focus on research studies examining protein O-GlcNAcylation in the context of cardiac hypertrophy.