Recent data from this laboratory suggest that components of dairy foods may serve as activators of SIRT1 (Silent Information Regulator Transcript 1), and thereby participate in regulation of glucose and lipid metabolism. In this study, an ex-vivo/ in-vitro approach was used to examine the integrated effects of dairy diets on SIRT1 activation in two key target tissues (adipose and muscle tissue). Methods: Serum from overweight and obese subjects fed low or high dairy diets for 28 days was added to culture medium (similar to conditioned media) to treat cultured adipocytes and muscle cells for 48 hours. Results: Treatment with high dairy group conditioned media resulted in 40% increased SIRT1 gene expression in both tissues (p<0.01) and 13% increased enzyme activity in adipose tissue compared to baseline. This was associated with increased gene expression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1alpha), nuclear respiratory factor 1 (NRF1), cytochrome oxidase c subunit 7 (Cox 7), NADH dehydrogenase and uncoupling protein 2 (UCP2) in adipocytes as well as uncoupling protein 3 (UCP3), NRF1 and Cox 7 in muscle cells (p<0.05). Further, direct incubation of physiological concentrations of leucine and its metabolites alpha-Ketoisocaproic acid (KIC) and beta-hydroxy-methylbuteric acid (HMB) with recombinant human SIRT1 enzyme resulted in 30 to 50% increase of SIRT1 activity (p<0.05). Conclusions: These data indicate that dairy consumption leads to systemic effects, which may promote mitochondrial biogenesis in key target tissues such as muscle and adipose tissue both by direct activation of SIRT1 as well as by SIRT1-independent pathways.
Adipocyte numbers and peroxisome proliferators activated receptorgamma (PPARgamma) expression of retroperitoneal tissue increased while area under the curve (AUC) during the glucose tolerance test (GTT) was reduced in rats subjected to certain feed withdrawal (FW) regimens. Thus ... more
Visceral obesity and insulin resistance are associated with a postprandial accumulation of atherogenic chylomicron remnants that is difficult to modulate with lipid-lowering therapies. Dietary fish oil and exercise are cardioprotective interventions that can significantly modif ... more
Despite the appearance of new treatment, dietary approach remains the mainstay of PKU therapy. The nutritional management has become complex to optimize PKU patients' growth, development and diet compliance. This paper review critically new advances and challenges that have recently focu ... more
Non-invasive 'liquid biopsies' can find metastatic or recurrent prostate cancer, in a low cost assay suitable for most healthcare systems, finds research published in Genome Medicine. Genomic signatures of prostate cancer, isolated from plasma DNA, display abnormal copy numbers of specific ... more
Watermelon juice can be a valuable source of biofuel. Researchers writing in BioMed Central's open access journal Biotechnology for Biofuels have shown that the juice of reject watermelons can be efficiently fermented into ethanol.
Wayne Fish worked with a team of researchers at the USDA-A ... more
The active ingredient in many insect repellents, deet, has been found to be toxic to the central nervous system. Researchers writing in BMC Biology say that more investigations are urgently needed to confirm or dismiss any potential neurotoxicity to humans, especially when deet-based repell ... more