Showing papers by "Sridevi Devaraj published in 2011"

Adipose tissue dysregulation in patients with metabolic syndrome.

Abstract: Context: The metabolic syndrome (MetS) is associated with increased risk of diabetes and cardiovascular disease (CVD). Numerous groups have shown increased circulating biomarkers of inflammation in MetS. However, there are scanty data on the cellular sources contributing to this low-grade inflammation. Objective: The aim of this study was to determine the role of sc adipose tissue (SAT) biology in nascent MetS without concomitant diabetes or CVD. Patients and Methods: Subjects with MetS and controls were recruited after informed consent. Fasting blood was collected, and SAT was obtained by biopsy. Results: Circulating biomarkers of inflammation and insulin resistance, high-sensitivity C-reactive protein (hsCRP), IL-6, IL-1β, leptin, serum amyloid A, and retinol-binding protein-4 (RBP-4) concentrations were significantly higher in the MetS subjects than controls, whereas adiponectin concentrations were lower. In SAT, leptin, RBP-4, CRP, serum amyloid A, plasminogen activator inhibitor-1, IL-1, IL-6, IL-8, ...

Epigenetic regulation of high glucose-induced proinflammatory cytokine production in monocytes by curcumin.

Abstract: Diabetes is a proinflammatory state. We have previously shown increased monocyte proinflammatory cytokines in patients with Type 1 and Type 2 diabetes. High glucose induces proinflammatory cytokines via epigenetic changes. Curcumin, a polyphenol responsible for the yellow color of the spice turmeric, is known to exert potent anti-inflammatory activity in vitro. Recent studies indicate that it may regulate chromatin remodeling by inhibiting histone acetylation. In this study, we aimed to test the effect of curcumin on histone acetylation and proinflammatory cytokine secretion under high-glucose conditions in human monocytes. Human monocytic (THP-1) cells were cultured in presence of mannitol (osmolar control, mannitol) or normoglycemic (NG, 5.5 mmol/L glucose) or hyperglycemic (HG, 25 mmol/L glucose) conditions in absence or presence of curcumin (1.5–12.5 μM) for 72 h. Cytokine level, nuclear factor κB (NF-κB) transactivation, histone deacetylases (HDACs) activity, histone acetylases (HATs) activity were measured by western blots, quantitative reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence staining. HG significantly induced histone acetylation, NF-κB activity and proinflammatory cytokine (interleukin 6, tumor necrosis factor α and MCP-1) release from THP-1 cells. Curcumin suppressed NF-κB binding and cytokine release in THP-1 cells. Also, since p300 histone acetyltransferase is a coactivator of NF-κB, we examined its acetylation. Curcumin treatment also significantly reduced HAT activity, level of p300 and acetylated CBP/p300 gene expression, and induced HDAC2 expression by curcumin. These results indicate that curcumin decreases HG-induced cytokine production in monocytes via epigenetic changes involving NF-κB. In conclusion, curcumin supplementation by reducing vascular inflammation may prevent diabetic complications.

CD11c/CD18 Expression Is Upregulated on Blood Monocytes During Hypertriglyceridemia and Enhances Adhesion to Vascular Cell Adhesion Molecule-1

Abstract: Objective— Atherosclerosis is associated with monocyte adhesion to the arterial wall that involves integrin activation and emigration across inflamed endothelium. Involvement of β2-integrin CD11c/CD18 in atherogenesis was recently shown in dyslipidemic mice, which motivates our study of its inflammatory function during hypertriglyceridemia in humans. Methods and Results— Flow cytometry of blood from healthy subjects fed a standardized high-fat meal revealed that at 3.5 hours postprandial, monocyte CD11c surface expression was elevated, and the extent of upregulation correlated with blood triglycerides. Monocytes from postprandial blood exhibited an increased light scatter profile, which correlated with elevated CD11c expression and uptake of lipid particles. Purified monocytes internalized triglyceride-rich lipoproteins isolated from postprandial blood through low-density lipoprotein–receptor–related protein-1, and this also elicited CD11c upregulation. Laboratory-on-a-chip analysis of whole blood showed that monocyte arrest on a vascular cell adhesion molecule-1 (VCAM-1) substrate under shear flow was elevated at 3.5 hours and correlated with blood triglyceride and CD11c expression. At 7 hours postprandial, blood triglycerides decreased and monocyte CD11c expression and arrest on VCAM-1 returned to fasting levels. Conclusion— During hypertriglyceridemia, monocytes internalize lipids, upregulate CD11c, and increase adhesion to VCAM-1. These data suggest that analysis of monocyte inflammation may provide an additional framework for evaluating individual susceptibility to cardiovascular disease.

Knockout of Toll-Like Receptor-2 Attenuates Both the Proinflammatory State of Diabetes and Incipient Diabetic Nephropathy

Abstract: Objective— Type 1 diabetes (T1DM) is a proinflammatory state and confers an increased risk for vascular complications. Toll-like receptors (TLR) could participate in diabetic vasculopathies. Whether TLR activation contributes to the proinflammatory state of T1DM and the pathogenesis of diabetic nephropathy remains unknown. Methods and Results— We induced T1DM in TLR2 knockout mice (TLR2−/−) and wild-type littermates (C57BL/6J-WT) using streptozotocin (STZ). Fasting blood, peritoneal macrophages, and kidneys were obtained for flow cytometry, Western blot, microscopy, and cytokine assays at 6 and 14 weeks after induction of diabetes. Macrophage TLR2 expression and MyD88-dependent signaling were increased in diabetic mice (WT+STZ) compared with nondiabetic WT mice. These biomarkers were attenuated in diabetic TLR2−/− macrophages. WT+STZ mice showed increased kidney:body weight ratio due to cell hypertrophy, increased albuminuria, decreased kidney nephrin, podocin, and podocyte number and increased transforming growth factor-β and laminin compared with WT mice. Nephrin, podocin, and podocyte number and effacement were restored, and transforming growth factor-β and laminin levels were decreased in TLR2−/−+ STZ mice kidneys versus WT+STZ. Peritoneal and kidney macrophages were predominantly M1 phenotype in WT+STZ mice; this was attenuated in TLR2−/−+STZ mice. Conclusion— These data support a role for TLR2 in promoting inflammation and early changes of incipient diabetic nephropathy, in addition to albuminuria and podocyte loss.

C-Reactive Protein Polarizes Human Macrophages to an M1 Phenotype and Inhibits Transformation to the M2 Phenotype

Abstract: Objective— Inflammation is pivotal in atherosclerosis. Monocyte-macrophages are crucial in atherosclerosis. Monocytes can develop into subsets: classically (M1) or alternatively (M2) activated cells. Several studies point to a proinflammatory role for C-reactive protein (CRP). Because there is a paucity of data on the effects of CRP on macrophage phenotype, we tested effects of CRP on macrophage polarization. Methods and Results— Monocytes were incubated with CRP (0 to 50 μg/mL) and differentiated into macrophages for 7 days. Phenotypic characterization of M1 and M2 macrophages was performed using flow cytometry. CRP treatment resulted in increased population of M1 macrophages (tumor necrosis factor [TNF]/interleukin [IL]-12/C-C chemokine receptor 2, TNF/IL-12/monocyte chemotactic protein-1, or TNF/IL-1/IL-12). These effects were not abrogated by polymixin B or small interfering RNA to Toll-like receptor-4, but they were abrogated by boiled CRP. Administration of human CRP to rats in vivo increased polarization of macrophages to M1 phenotype compared with human serum albumin. When macrophages were primed to the M2 phenotype with IL-4, addition of CRP resulted in significantly increased secretion of TNF-α, MCP-1, and IL-1 and conversion of macrophages from the M2 to the M1 phenotype. CRP failed to prime macrophages to the M1 phenotype in presence of CD32/CD64 small interfering RNA or dominant-negative nuclear factor kappa B. Conclusion— Collectively, these results further support a role for CRP in promoting differentiation of human monocytes toward a proinflammatory M1 phenotype.

Resveratrol upregulates SIRT1 and inhibits cellular oxidative stress in the diabetic milieu: mechanistic insights

Abstract: Oxidative stress is pivotal in diabetic complications. Loss of SIRT1 activity may be associated with diabetes. SIRT1 can regulate FOXO transcription. However, interactions between SIRT1 and FOXO un...

Demonstration of increased toll-like receptor 2 and toll-like receptor 4 expression in monocytes of type 1 diabetes mellitus patients with microvascular complications

Abstract: Type 1 diabetes mellitus (T1DM) is associated with increased microvascular complications and is a proinflammatory state. The toll-like receptors (TLRs) are pattern recognition receptors on monocytes and important in atherosclerosis. We have shown increased TLR2 and TLR4 expression on monocytes of T1DM compared with controls. In this report, we tested the surface expression of TLR2 and TLR4 on monocytes of T1DM patients with microvascular complications (T1DM-MV) compared with those without (T1DM) and healthy controls. The study was performed at the University of California Davis. Healthy controls (n = 31), T1DM patients (n = 31), and T1DM-MV patients (n = 34) were included. The TLR2 and TLR4 surface expression was significantly increased in T1DM-MV monocytes compared with T1DM and controls (P < .01). In addition, nuclear factor κB activity and interleukin-1β release were significantly increased in monocytes from T1DM-MV compared with T1DM (P < .005). Thus, we make the novel observation that TLR2 and TLR4 expression and signaling are increased in T1DM-MV compared with T1DM and may contribute to the accentuated proinflammatory state and complications of T1DM.

Induction of apoptosis by eugenol in human breast cancer cells.

Abstract: In the present study, potential anticancer effect of eugenol on inhibition of cell proliferation and induction of apoptosis in human MCF-7 breast cancer cells was investigated. Induction of cell death by eugenol was evaluated following MTT assay and monitoring lactate dehydrogenase released into the culture medium for cell viability and cytotoxicity, giemsa staining for morphological alterations, fluorescence microscopy analysis of cells using ethidium bromide and acridine orange and quantitation of DNA fragments for induction of apoptosis. Effect of eugenol on intracellular redox status of the human breast cancer cells was assessed by determining the level of glutathione and lipid peroxidation products (TBARS). Eugenol treatment inhibited the growth and proliferation of human MCF-7 breast cancer cells through induction of cell death, which was dose and time dependent. Microscopic examination of eugenol treated cells showed cell shrinkage, membrane blebbing and apoptotic body formation. Further, eugenol treatment also depleted the level of intracellular glutathione and increased the level of lipid peroxidation. The dose dependent increase in the percentage of apoptotic cells and DNA fragments suggested that apoptosis was involved in eugenol induced cell death and apoptosis might have played a role in the chemopreventive action of eugenol.

Low vitamin D levels correlate with the proinflammatory state in type 1 diabetic subjects with and without microvascular complications.

Abstract: Epidemiologic studies link vitamin D deficiency to onset of type 1 diabetes mellitus (T1DM). T1DM exhibits increased inflammation, which is pronounced with microvascular complications (T1DM-MV). However, there are a paucity of data on vitamin D in T1DM-MV in relation to biomarkers of inflammation, and this formed the aim of the study. Healthy control subjects (n = 36), patients with T1DM (n = 24), and patients with T1DM-MV (n =26) were recruited. Serum vitamin D levels, monocyte toll-like receptor (TLR) 2 and TLR4 expression and nuclear factor-κB (NFκB) activity were assessed. Patients with T1DM and T1DM-MV were significantly vitamin D deficient compared with control subjects (P < .01). There was a significant negative correlation between vitamin D levels and high-sensitivity C-reactive protein, NFκB activity, and TLR4 expression (P < .05). Preincubation with vitamin D significantly decreased lipopolysaccharide-activated TLR4 expression and cytokine levels in monocytes (P < .05). Low vitamin D levels may contribute to increased inflammation in T1DM. Future studies will elucidate the immunomodulatory effects of vitamin D in decreasing vascular risk in this population.

C-Reactive Protein Induces Release of Both Endothelial Microparticles and Circulating Endothelial Cells In Vitro and In Vivo: Further Evidence of Endothelial Dysfunction

Abstract: BACKGROUND: Inflammation is pivotal in atherosclerosis A key early event in atherosclerosis is endothelial dysfunction C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a risk marker for cardiovascular disease, and there is mounting evidence to support its role in atherothrombosis CRP has been shown to promote endothelial dysfunction both in vitro and in vivo Emerging biomarkers of endothelial dysfunction include circulating endothelial cells (CECs) and endothelial microparticles (EMPs) However, there is a paucity of data examining the effect of CRP on CEC and EMP production in vitro and in vivo METHODS: In this report, we treated human aortic endothelial cells (HAECs) with increasing concentrations of CRP (0–50 μg/mL) or boiled CRP We counted CECs and EMPs by flow cytometry RESULTS: Although CRP treatment resulted in a significant increase in release of both CECs and EMPs, boiled CRP failed to have an effect Pretreatment of HAECs with sepiapterin or diethylenetriamine NONOate, both of which preserve nitric oxide (NO), resulted in attenuation of CRP's effects on CECs and EMPs CD32 and CD64 blocking antibodies but not CD16 antibody or lectin-like oxidized LDL receptor 1 small interfering RNA (LOX-1 siRNA) prevented CRP-induced production of CECs and EMPs Furthermore, delivery of human CRP to Wistar rats compared with human serum albumin resulted in significantly increased CECs and EMPs, corroborating the in vitro findings CONCLUSIONS: We provide novel data that CRP, via NO deficiency, promotes endothelial dysfunction by inducing release of CECs and EMPs, which are biomarkers of endothelial dysfunction

S-adenosyl-L-methionine treatment for alcoholic liver disease: A double-blinded, randomized, placebo-controlled trial

Abstract: Background S-adenosyl-L-methionine (SAM) is the methyl donor for all methylation reactions and regulates the synthesis of glutathione (GSH), the main cellular antioxidant. Previous experimental studies suggested that SAM may benefit patients with established alcoholic liver diseases (ALD). The aim of this study was to determine the efficacy of SAM in treatment of ALD in a 24 week trial. The primary endpoints were changes in serum aminotransferase levels and liver histopathology scores, and the secondary endpoint was changes in serum levels of methionine metabolites.

Low vitamin D levels in Northern American adults with the metabolic syndrome.

Abstract: Metabolic syndrome (MetS), is a constellation of cardiometabolic disease risk factors, that affects 1 in 3 US adults and predisposes to increased risks for both diabetes and cardiovascular disease. While epidemiological studies show low vitamin D [(25(OH)D] levels in MetS, there is sparse data on vitamin D status in MetS patients in North America. Thus, the aim of our study was to examine plasma vitamin D concentration among adults with MetS in Northern California (sunny climate), but without diabetes or cardiovascular disease. 25(OH)D levels were significantly decreased in MetS compared to controls. 8 % of controls and 30% of MetS North American adult subjects were deficient in 25(OH)D (<20 ng/ml; p=0.0236, Controls vs. MetS). There were no significant differences between the groups with respect to blood sampling in winter and summer months, total calcium and phosphate, and creatinine levels. Vitamin D levels were significantly inversely correlated with fasting glucose (r=-0.29, p=0.04) and HOMA (r=-0.34, p=0.04). Future studies of vitamin D supplementation in these subjects on subsequent risk of diabetes will prove instructive with respect to potential health claims in these high risk patients with MetS.

Statin therapy in metabolic syndrome and hypertension post-JUPITER: what is the value of CRP?

Abstract: Much evidence supports a pivotal role for inflammation in atherosclerosis C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a cardiovascular risk marker and may also promote atherogenesis CRP levels are increased in metabolic syndrome and hypertension and confer increased risk of cardiovascular events in patients in these subgroups Statins have been shown to lower low-density lipoproteins and CRP independently, and reduce cardiovascular events in subjects with and without metabolic syndrome and hypertension In this review, we focus on the results from the primary prevention statin trial, Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), which showed reductions in LDL, CRP, and cardiovascular events Post-JUPITER, the new guidelines will now need to consider recommending high-sensitivity CRP testing to intermediate-risk metabolic syndrome patients and those with hypertension and intermediate risk so that we can better identify candidates at greater risk and reduce cardiovascular burden in these subjects with statin therapy

CRP induces hypertension in animal models: homo sapiens says no.

Abstract: C-reactive protein (CRP) is a prototypic downstream marker of inflammation. Recent data have suggested that CRP is an independent risk marker for cardiovascular disease. In addition, numerous lines of evidence support the thesis that CRP could participate in atherothrombosis.1 In both in-vitro and in-vivo studies, one of the most uniform findings is the inhibition of endothelial nitric oxide synthase (eNOS) and impaired endothelial vasoreactivity, following CRP administration.2 Epidemiological studies support a relationship between higher levels of CRP predicting hypertension.3 In this issue of the journal, Li et al.4 show that delivery of CRP via a single injection of adeno-associated virus (AAV) over expression of human CRP (AAV– hCRP) vs. AAV–green fluorescent protein results in an increase of CRP upto 25 mg l 1 in Sprague–Dawley rats. Coupled with this increased CRP, they show an increase in both systolic and intra-arterial blood pressure (BP). In an attempt to elucidate the molecular mechanisms, they show an increase in reactive oxygen species possibly due to increased NADPH oxidase activity and decreased SOD1, decreased eNOS and an increase in Rho kinase. All these suggested mechanisms could result in an increase in hypertension. This study follows a previous report in which Guan et al.5 reported that a single injection of AAV–hCRP into male Wistar rats resulted in efficient sustained expression of CRP in the liver, together with an increase in serum CRP to 15 mg l 1 at 2–4 months compared with AAV–green fluorescent protein. Most importantly in this paper, they also showed that human CRP resulted in an increase in systolic and mean arterial pressure. Collectively in these papers, results showed that in addition to impaired vasoreactivity, there was an increase in the expression of angiotensin-1 (AT-1) receptors, endothelin-1 and the ETA type-1 receptors. They also showed a decreased expression of eNOS and AT-2 receptors. This was accompanied by impairment in endotheliumdependent vasorelaxation. Previously, Vongpatanasin et al.6 reported that CRP induces hypertension in CF1 transgenic mice expressing rabbit CRP (CF1–CRP) under the regulation of the phosphoenolpyruvate carboxykinase promoter, compared with wild-type CF1 control. CRP levels attained were about 10–15 mg l 1. It should be emphasized, however, that unlike the current study and the study by Guan et al.,5 they suggested this effect was not attributable to the effect of theAT-1 receptor, which was unaltered, but to a decrease in the AT-2 receptor. However, the study by Vongpatanasin et al.6 provided little further information with regard to molecular insights. Recently, Pravanec et al.7 reported that in spontaneously hypertensive rats, human CRP under the control of the apolipoprotein E promoter resulted in a substantial increase in human CRP levels. This increase in CRP resulted in an increase in both systolic and diastolic BPs measured by telemetry, compared with the spontaneously hypertensive rat controls. They suggest in their paper that CRP resulted in induction in many features of the metabolic syndrome. Transgenic spontaneously hypertensive rats exhibited insulin resistance, hypertriglyceridemia, hypertension, reduced serum adiponectin and microalbuminuria. Transgenic spontaneously hypertensive rats had evidence of inflammation and oxidative tissue damage with increased serum levels of interleukin 6 and increased hepatic and renal thiobarbituric acid-reactive substances, suggesting that oxidative stress may be mediating adverse effects of increased human CRP. A major critique of this manuscript is that human CRP levels attained in the study of 250 mg l 1 are clearly not what is seen in patients with metabolic syndrome or hypertension. Rather, it is more akin to levels seen in patients with macroinflammation, such as bacterial infections and so on. Thus, the relevance of these findings with regard to hypertension and metabolic syndrome is questionable. However, the reports of the Vongpatanasin and the Wang group convincingly demonstrate that induction of CRP levels upto 25 mg l 1 results in a significant increase in BP. Thus, it appears the CRP could induce hypertension in three different animal models through various molecular mechanisms (potential mechanisms with CRP that could culminate in hypertension are depicted in Figure 1). These include an increase in ET-1, a decrease in eNOS and vasoreactivity, an increase in reactive oxygen species, modulation of AT receptors, and a decrease in prostacyclin, a potent vasodilator. This latter mechanism was not studied by any of the previous groups but was previously reported by Venugopal et al.8 Also, recently it was shown that CRP can in the presence of aldosterone promote endothelial stiffness.9 The paper by Li et al.4 goes on to show that the use of rosuvastatin results in a reduction in CRP-induced hypertension compared with controls. They also show that the use of rosuvastatin ameliorated the deleterious effects of CRP and advanced this as a Dr I Jialal and Dr D Siegel are at the VA Medical Center, Mather, CA, USA and Dr I Jialal and Dr S Devaraj are at the Department of Pathology & Laboratory Medicine, University of California at Davis Medical Center, Sacramento, CA, USA. E-mail: ishwarlal.jialal@ucdmc.ucdavis.edu Hypertension Research (2011) 34, 801–802 & 2011 The Japanese Society of Hypertension All rights reserved 0916-9636/11 $32.00

Laboratory diagnosis of ethylene glycol poisoning: the cup is half full?

Abstract: The major toxic alcohols that pose a risk to human health and for which measurement of levels is requested from the clinical laboratory include ethanol, ethylene glycol, isopropanol, and methanol. Most clinical laboratories are equipped to accurately quantitate ethanol levels, mainly by an enzymatic assay on an automated chemistry analyzer platform. However, the measurement of the other 3 alcohols is more challenging.1,2 Some relevant laboratory tests that assist in the differential diagnosis are listed in Table 1. An increase in the osmolal gap is evident in the presence of all of the alcohols. In addition, methanol, ethanol, and ethylene glycol also result in an increase in metabolic acidosis with an increased anion gap, separating them from isopropanol. A relevant clue to isopropanol ingestion is positivity for acetone in the urine or blood without attendant hyperglycemia. In addition to an increase in the osmolal gap and anion gap acidosis, ethylene glycol ingestion can result in a positive urine analysis for the presence of calcium oxalate crystals (monohydrate and dihydrate) because it is converted to oxalate, which can chelate calcium and result in hypocalcemia. However, it needs to …

Novel Cholesteryl Ester Transfer Protein Inhibitors: Promising Therapy for Dyslipidemia?

Abstract: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in developed countries. Statins are the mainstay of cardiovascular prevention and can reduce cardiovascular risk by almost 50% over a 5-year period by effectively lowering low-density lipoprotein cholesterol (LDL-C). Low levels of high-density lipoprotein cholesterol (HDL-C) are a major risk factor that confers increased cardiovascular risk in population studies and most recently in statin-treated patients. In addition to enhancing reverse cholesterol transport, HDL-C appears to be an antioxidant and an endogenous anti-inflammatory agent, and it preserves endothelial function. Thus, therapies increasing HDL-C levels and improving functionality may reduce cardiovascular risk by slowing the development of atherosclerosis. Epidemiological studies indicate that each 1 mg/dL increase in plasma HDL-C concentration is associated with a 4% decrease in the risk of death from CVD, independent of LDL-C concentration. However, current approaches for increasing HDL-C are limited. Although niacin has been shown to reduce atherosclerotic CVD in the Coronary Drug Project, and probably rescues atherosclerosis plaque in coronary and carotid arteries in the FATS and ARBITER studies, its ability to increase HDL-C is associated with side effects, such as flushing, hyperuricemia, liver dysfunction, and exacerbating dysglycemia, thus limiting its use in uncontrolled diabetics and patients with metabolic syndrome. One novel approach to treating CVD is via elevation of HDL-C levels by inhibiting cholesteryl ester transfer protein (CETP).