Improved myocardial perfusion in chronic diabetic mice by the up-regulation of pLKB1 and AMPK signaling.

Previous studies related impaired myocardial microcirculation in diabetes to oxidative stress and endothelial dysfunction. Thus, this study was aimed to determine the effect of up-regulating pAMPK-pAKT signaling on coronary microvascular reactivity in the isolated heart of diabetic mice. We measured coronary resistance in wild-type and streptozotocin (STZ)-treated mice, during perfusion pressure changes. Glucose, insulin, and adiponectin levels in plasma and superoxide formation, NOx levels and heme oxygenase (HO) activity in myocardial tissue were determined. In addition, the expression of HO-1, 3-nitrotyrosine, pLKB1, pAMPK, pAKT, and peNOS proteins in control and diabetic hearts were measured. Coronary response to changes in perfusion pressure diverged from control in a time-dependent manner following STZ administration. The responses observed at 28 weeks of diabetes (the maximum time examined) were mimicked by L-NAME administration to control animals and were associated with a decrease in serum adiponectin and myocardial pLKB1, pAMPK, pAKT, and pGSK-3 expression. Cobalt protoporphyrin treatment to induce HO-1 expression reversed the microvascular reactivity seen in diabetes towards that of controls. Up-regulation of HO-1 was associated with an increase in adiponectin, pLKB1, pAKT, pAMPK, pGSK-3, and peNOS levels and a decrease in myocardial superoxide and 3-nitrotyrosine levels. In the present study we describe the time course of microvascular functional changes during the development of diabetes and the existence of a unique relationship between the levels of serum adiponectin, pLKB1, pAKT, and pAMPK activation in diabetic hearts. The restoration of microvascular function suggests a new therapeutic approach to even advanced cardiac microvascular derangement in diabetes.

Serum albumin fragmentation in end-stage renal disease patients--a pilot study.

BACKGROUND: The goal of this study was to detect modification in the expression of plasma proteins and/or post-translational modifications of their structure in patients with end stage renal disease. METHODS: Serum samples from 19 adult patients treated by maintenance hemodialysis (MHD) were analyzed in comparison to sera from six healthy controls using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2DE). Spots of interest were identified by mass spectrometry analysis. In addition, the 2DE maps were incubated with a human anti-albumin polyclonal antibody. RESULTS: SDS-PAGE gels, 2DE maps and matrix-assisted laser desorption/ionization time of flight analysis indicated over-expression of low-molecular weight proteins (LMWP) in sera from patients. Unexpectedly, another 15 spots with estimated M(r) of 12.5-29 kDa from the 2DE maps of six patients were identified as fragments of albumin. 2D immunoblotting of sera from 12 other patients detected numerous albumin fragments. CONCLUSIONS: These results indicate that in addition to increased expression of LMWP, a relevant amount of albumin fragments are detectable in the serum of patients undergoing MHD. Uremia appears to facilitate the fragmentation of albumin and/or the retention of albumin fragments in blood.

The L-4F mimetic peptide prevents insulin resistance through increased levels of HO-1, pAMPK, and pAKT in obese mice.

We examined mechanisms by which L-4F reduces obesity and diabetes in obese (ob) diabetic mice. We hypothesized that L-4F reduces adiposity via increased pAMPK, pAKT, HO-1, and increased insulin receptor phosphorylation in ob mice. Obese and lean mice were divided into five groups: lean, lean-L-4F-treated, ob, ob-L-4F-treated, and ob-L-4F-LY294002. Food intake, insulin, glucose adipocyte stem cells, pAMPK, pAKT, CB1, and insulin receptor phosphorylation were determined. Subcutaneous (SAT) and visceral adipose tissue (VAT) were determined by MRI and hepatic lipid content by magnetic resonance spectroscopy. SAT and VAT volumes decreased in ob-L-4F-treated animals compared with control. L-4F treatment decreased hepatic lipid content and increased the numbers of small adipocytes (P < 0.05) and phosphorylation of insulin receptors. L-4F decreased CB1 in SAT and VAT and increased pAKT and pAMPK in endothelium. L-4F-mediated improvement in endothelium was prevented by LY294002. Inhibition of pAKT and pAMPK by LY294002 was associated with an increase in glucose levels. Upregulation of HO-1 by L-4F produced adipose remodeling and increased the number of small differentiated adipocytes. The anti-obesity effects of L-4F are manifested by a decrease in visceral fat content with reciprocal increases in adiponectin, pAMPK, pAKT, and phosphorylation of insulin receptors with improved insulin sensitivity.

Effects of the incubation in vitro with sorbents on serum proteomic pattern and cytokine concentration in cancer patients during chemotherapy--preliminary results.

INTRODUCTION: Cancer and treatment by chemotherapy often produce abnormalities in endogenous cytokine, chemokine, and inflammatory mediator production. Sorbent-based adsorption therapies have been used to remove cytokines in diverse human diseases. AIM: The aim of this study was to evaluate the effects of chemotherapy on serum proteomic pattern and cytokine concentration, and to evaluate the ex vivo feasibility of using sorbents to remove cytokines, chemokines and other proteins in adult cancer patients undergoing chemotherapy with fluorouracil or carboplatin-taxane combinations. PATIENTS AND METHODS: Serum samples of three female adult patients (one affected by rectal cancer and two by ovarian cancer) were examined before and on the fourth day of the first cycle of chemotherapy with fluorouracil (rectal cancer patient) or carboplatin-taxane combination (ovarian cancer patients). The analysis was performed, by means of luminex technology and with a proteomic approach, on native serum samples, and on the same sera after 2 hours of in vitro incubation with a synthetic based styrenic divinylbenzene resin. RESULTS: Chemotherapy determined variable effects on serum concentration of cytokines, while the incubation in vitro of patients serum samples with the resin induced a significant decrease (>80%) in serum concentration of different chemokines, cytokines, growth factors and proteins. The proteomic approach, using SDS PAGE and 2-DE highlighted differences in protein expression between sera from healthy controls and cancer patients. Proteomic analysis demonstrated also variations in the expression of proteins, particularly those with low-molecular weight, due to chemotherapy. Finally, the incubation in vitro of serum samples with sorbents induced a general reduction of protein expression. Within the cancer patients maps, 10 spots were chosen for identification with MALDI-TOF analysis. CONCLUSION: The incubation in vitro with sorbents normalized the over-expression of different proteins and cytokines induced by chemotherapy, suggesting further evaluation as a possible adjuvant treatment.