Characterization of coconut oil and CLA induced lipolysis

Obesity is a main health concern and leads to many other health complications. Conjugated linoleic acid (CLA) has been shown to cause a reduction in obesity in several species. CLAinduced body fat loss is enhanced when mice are fed coconut oil (CO). The objectives were to determine if the CLA-induced lipolysis in different oil source-fed mice was time-dependent and to determine the effect of cell signaling inhibitors on CO+CLA-induced lipolysis. Study 1: Male mice (ICR; n=80; 3wk) were fed 7% soybean oil (SO) or CO diets for 6wk and then supplemented with 0 or 0.5% CLA for 3, 7, 10 or 14d. Body fat index (BFI) was calculated as [(epididymal fat pad + retroperitoneal fat pad)/ body weight] and lipolysis was determined by non-esterified fatty acid (NEFA) and glycerol release in 3hr ex vivo cultures. BFI was reduced by CO on d7 (P\u3c0.01) and CLA tended (P=0.09) to decrease BFI in CO-fed mice on d10. BFI was reduced in both CO and SO-fed mice (P\u3c0.05) in response to CLA on d14. NEFA release was increased by CLA in CO-fed mice (P\u3c0.01) but not in SO-fed mice on d7 and 10 but on d14 CLA increased NEFA release in both CO and SO-fed mice (P\u3c0.0001). Glycerol release was also increased by CLA in CO-fed mice but not in SO-fed mice on d3 and d7 (P\u3c0.05). We then determined expression and activation level of proteins involved in lipolysis and lipogenesis. CLA tended to decrease (P=0.06) p-perilipin protein expression in CO-fed mice. There was also a trend for CLA (P=0.06) to decrease adipose triglyceride lipase (ATGL) protein. CO-fed mice had greater fatty acid synthase, stearoyl CoA desaturase 1 mRNA expression and less acetyl CoA carboxylase mRNA expression (P\u3c0.01). Sterol regulatory binding protein 1c and malic enzyme expression was least in CO+CLA-fed mice. Study 2: 3T3-L1 cells were differentiated, exposed to CO or SO for 10d, serum starved overnight, and pre-loaded with 3[H]-oleic acid for 12 hrs. Cells were treated with 50 muM CLA or linoleic acid (LA) with/without cell signaling inhibitors for 12-24 hrs. Lipolysis was measured as the 3-hr release of 3[H]-oleic acid. Without inhibitors, CO+CLA treatment caused more lipolysis (P\u3c0.01) than all other treatments, which did not differ. None of the inhibitors tested reduced lipolysis in CO+CLA treated cells. Cyclooxegenase-2 inhibitor increased lipolysis of SO+CLA treated cells (P=0.05) to the level of CO+CLA. Phospholipase C inhibitor increased lipolysis in all treatments (P\u3c0.0001) except that of CO+CLA. Peroxisome proliferator-activated receptor alpha inhibitor also increased lipolysis of CO+LA (P\u3c0.05) to the level of CO+CLA treated cells and in SO+CLA treated cells. There was no effect of the p42 mitogen-activated protein kinase or protein kinase A inhibitor, compared to absence of inhibitor. Therefore CLA-induced lipolysis occurs more rapidly in CO vs SO-fed mice and the CLA enhanced lipolysis in CO group could involve the PLC pathway

Coconut oil enhancement of conjugated linoleic acid induced body fat loss and lipolysis in mice

Dietary conjugated linoleic acid (CLA) causes a body fat loss that is enhanced when mice are fed coconut oil (CO) compared to soy oil (SO). The objectives were to determine if CLA feeding altered proteins involved in lipolysis. Male mice (n = 80; 3 wk old) were fed 7% SO or CO diets for 6 wk then 0 or 0.5% CLA for 12d. A body fat index was calculated: (retroperitoneal (RP) + epididymal (EPI) fat pads)*100/body weight. Lipolysis was determined by non-esterified fatty acid (NEFA) and glycerol release from EPI & RP explants. The relative expression of perilipin, phosphorylated perilipin (P-perilipin), hormone sensitive lipase (HSL), phosphorylated HSL (P-HSL), adipocyte triglyceride lipase (ATGL), and adipocyte differentiation related protein (ADRP) were determined by western blotting. The body fat index was reduced by both CLA (P \u3c 0.05) and CO (P \u3c 0.001) but there was no interaction. NEFA release was increased by CLA in CO-fed mice (2.94 and 8.63 mumol/g; P \u3c 0.05) but not in SO-fed mice (1.76 vs 2.26 mumol/g tissue). Glycerol release was not affected by CO or CLA. Total perilipin had a main effect of oil source, where it was decreased by CO feeding (P \u3c 0.05) but P-perilipin tended to be increased by CLA in SO-fed mice and decreased by CLA in CO-fed mice (P = 0.08). HSL expression had a main effect of oil source where CO feeding decreased the expression (P \u3c 0.05), but P-HSL expression wasn\u27t affected by diet. ATGL expression had a main effect of oil source, it was decreased by CO feeding (P \u3c 0.01) but wasn\u27t altered by CLA. This may indicate that the CLA-stimulated lipolysis in CO-fed mice is on the decline since P-perilipin, and P-HSL are associated with increased lipase activity. ADRP expression wasn\u27t affected by any diet, suggesting that there is no significant de-differentiation of adipocytes in vivo. In conclusion coconut oil enhances the anti-obesity effect of CLA and this effect is, at least in part, due to enhanced lipolysis

Effect of pregnancy-induced mass gain and footwear on postural stability

Pregnancy induces tremendous changes in the body, which increases the risk of falling. Falls are rarely as costly as when they happen during pregnancy, leading to tremendous healthcare, emotional, and societal costs. More than one in four women (27%) fall at least once during pregnancy. Despite overwhelming statistics, there is a dearth of interventions to minimize the risk of falling amongst pregnant women. Our goal was to quantify the effect of pregnancy-induced mass gain and footwear on postural stability throughout pregnancy, as a first step towards a deeper understanding of pregnancy-specific optimal postural strategies. Our main hypothesis was that both footwear and pregnancy mass affect postural stability.Postural stability was assessed on ten young healthy non-pregnant women and pregnancy was simulated by adding localized weights. Measurements were performed during four sessions (not pregnant, first, second, and third trimesters) wearing five types of footwear in randomized order: flats, sports, low heels, and sports and low heels with ankle brace. The center of pressure (COP) was determined for each instant in time and 22 COP-based postural stability indices (15 temporal and 7 spectral) were computed. The effect of pregnancy-induced mass gain and footwear on each index was assessed using repeated measures ANOVA.Pregnancy-induced mass gain and footwear have an influence on the postural stability of healthy young female subjects, independently of all other pregnancy-induced physical, hormonal, and psychological changes. Results demonstrated a decrease in mediolateral postural stability with mass gain and footwear such as heels. Ankle braces worn with sport shoes seem to increase postural stability. The decrease in postural stability is detected by a decrease in postural sway, due to a tighter postural adjustment and a rigidification of the posture. This rigidification of the posture results from muscle contraction, which would lead to muscle fatigue if performed continuously during a pregnancy.This study paves the way for a deeper understanding of postural strategies adopted by pregnant women while wearing different footwear, and thus for the development of efficient fall-avoidance strategies

RAGE limits regeneration after massive liver injury by coordinated suppression of TNF-α and NF-κB

The exquisite ability of the liver to regenerate is finite. Identification of mechanisms that limit regeneration after massive injury holds the key to expanding the limits of liver transplantation and salvaging livers and hosts overwhelmed by carcinoma and toxic insults. Receptor for advanced glycation endproducts (RAGE) is up-regulated in liver remnants selectively after massive (85%) versus partial (70%) hepatectomy, principally in mononuclear phagocyte-derived dendritic cells (MPDDCs). Blockade of RAGE, using pharmacological antagonists or transgenic mice in which a signaling-deficient RAGE mutant is expressed in cells of mononuclear phagocyte lineage, significantly increases survival after massive liver resection. In the first hours after massive resection, remnants retrieved from RAGE-blocked mice displayed increased activated NF-κB, principally in hepatocytes, and enhanced expression of regeneration-promoting cytokines, TNF-α and IL-6, and the antiinflammatory cytokine, IL-10. Hepatocyte proliferation was increased by RAGE blockade, in parallel with significantly reduced apoptosis. These data highlight central roles for RAGE and MPDDCs in modulation of cell death–promoting mechanisms in massive hepatectomy and suggest that RAGE blockade is a novel strategy to promote regeneration in the massively injured liver

Mrp1 is involved in lipid presentation and iNKT cell activation by Streptococcus pneumoniae

The CD1d pathway present lipid antigens resulting in the activation of iNKT cells but the complete pathway remains to be fully elucidated. Here, Chandra et al. use an siRNA screen and identify Mrp1 as crucial for CD1d lipid presentation and activation of iNKT in the context of Streptococcus pneumoniae infection

Cutting edge: proteolytic inactivation of poly(ADP-ribose) polymerase 1 by the Nlrp3 and Nlrc4 inflammasomes

Caspase-mediated cleavage of the DNA damage sensor poly(ADP-ribose) polymerase 1 (PARP1) is a hallmark of apoptosis. However, it remains unclear whether PARP1 is processed during pyroptosis, a specialized cell-death program that occurs upon activation of caspase-1 in inflammasome complexes. In this article, we show that activation of the Nlrp3 and Nlrc4 inflammasomes induces processing of full-length PARP1 into a fragment of 89 kDa in a stimulus-dependent manner. Macrophages deficient for caspase-1 and those lacking the inflammasome adaptors Nlrp3, Nlrc4, and ASC were highly resistant to cleavage, whereas macrophages lacking the downstream inflammasome effector caspase-7 were partially protected. A modest, but statistically significant, reduction in Nlrp3 inflammasome-induced pyroptosis was observed in PARP1 knockout macrophages. Thus, protease-mediated inactivation of PARP1 is a shared feature of apoptotic, necrotic, and pyroptotic cells

Presence of hepatitis E virus in sewage in northern India: frequency and seasonal pattern

Outbreaks of acute hepatitis E, associated with consumption of contaminated drinking water, are frequent in India. Sewage is a major source for contamination of surface water. Data on the presence of hepatitis E virus (HEV) in sewage in India are limited. The aim of this study was to look for the presence of HEV RNA in concentrates of sewage specimens collected from a major open sewage drain in Lucknow, India during August 2004 to July 2006, by the polymerase chain reaction, using primers specific for human HEV (genotype 1) or Indian swine HEV (genotype 4). Of the 192 sewage specimens tested, 79 (41%) showed presence of human HEV RNA. The positivity rate was higher during the second year (52/103 [51%]) than during the first year (27/89 [30%]; P = 0.005). The seasonal pattern of HEV RNA positivity was as follows: winter months (November to February): 28 of 61 (46%); summer months (March to June): 36 of 66 (55%); and, monsoon months (July to October) 15 of 65 (23%). There was no reported outbreak of hepatitis E in the city during the study period. Swine HEV RNA was not detected in any of the 69 specimens tested. Repeat testing confirmed the reproducibility of the results. In addition, nucleic acid sequencing of six sewage isolates showed that these belonged to HEV genotype 1. The study suggests that HEV infection and fecal viral excretion may be common in HEV-endemic regions throughout the year even during non-epidemic periods

Glucagon stimulates hepatic FGF21 secretion through a PKA- and EPAC-dependent posttranscriptional mechanism.

Previous studies have shown that whole body deletion of the glucagon receptor suppresses the ability of starvation to increase hepatic fibroblast growth factor 21 (FGF21) expression and plasma FGF21 concentration. Here, we investigate the mechanism by which glucagon receptor activation increases hepatic FGF21 production. Incubating primary rat hepatocyte cultures with glucagon, dibutyryl cAMP or forskolin stimulated a 3-4-fold increase in FGF21 secretion. The effect of these agents on FGF21 secretion was not associated with an increase in FGF21 mRNA abundance. Glucagon induction of FGF21 secretion was additive with the stimulatory effect of a PPARα activator (GW7647) on FGF21 secretion. Inhibition of protein kinase A (PKA) and downstream components of the PKA pathway [i.e. AMP-activated protein kinase and p38 MAPK] suppressed glucagon activation of FGF21 secretion. Incubating hepatocytes with an exchange protein directly activated by cAMP (EPAC)-selective cAMP analog [i.e. 8-(4-chlorophenylthio)-2'-O-methyladenosine-3', 5'-cyclic monophosphate (cpTOME)], stimulated a 3.9-fold increase FGF21 secretion, whereas inhibition of the EPAC effector, Rap1, suppressed glucagon activation of FGF21 secretion. Treatment of hepatocytes with insulin also increased FGF21 secretion. In contrast to glucagon, insulin activation of FGF21 secretion was associated with an increase in FGF21 mRNA abundance. Glucagon synergistically interacted with insulin to stimulate a further increase in FGF21 secretion and FGF21 mRNA abundance. These results demonstrate that glucagon increases hepatic FGF21 secretion via a posttranscriptional mechanism and provide evidence that both the PKA branch and EPAC branch of the cAMP pathway play a role in mediating this effect. These results also identify a novel synergistic interaction between glucagon and insulin in the regulation of FGF21 secretion and FGF21 mRNA abundance. We propose that this insulin/glucagon synergism plays a role in mediating the elevation in FGF21 production during starvation and conditions related to metabolic syndrome