Effect of PPAR-ß/δ agonist GW0742 treatment in the acute phase response and blood-brain barrier permeability following brain injury.

The systemic response to ischemic stroke is associated with the hepatic acute phase response (APR) that modulates leukocytes recruitment to the injured brain. The inappropriate recruitment of leukocytes to the brain parenchyma can result in blood-brain barrier (BBB) breakdown. Emerging data suggest that peroxisome proliferator-activated receptor beta/delta (PPAR-ß/δ) activation has a potential neuroprotective role in ischemic stroke. However, mechanisms of PPAR-ß/δ mediated protection in ischemic insults remain unclear. In the present study, we determined for the first time, the effects of GW0742, a PPAR-ß/δ agonist on the APR following brain injury and assessed the effects on BBB permeability and tight junction integrity via claudin-5, occludin, and zona occludens-1 expression. C57/BL6 mice were exposed to 1 hour of ischemia and received 10 minutes before reperfusion either a vehicle solution or GW0742. Hepatic expression of chemokines (C-X-C motif ligand: CXCL1, CXCL2, and CXCL10), serum amyloid A-1, tumor necrosis factor alpha, interleukin-1ß, and interleukin-6 was measured, and the extent of brain and hepatic neutrophil infiltration was determined. The results showed that GW0742 treatment decreased infarct volume and edema, reactant production and neutrophil recruitment to the brain and liver, which is a hallmark of the APR. GW0742 significantly reduced BBB leakage and metalloproteinase 9 expression and upregulated the expression of tight junction proteins. These findings may help to guide the experimental and clinical therapeutic use of PPAR-ß/δ agonists against brain injury.

Correlation of Oxidative Stress Parameters and Inflammatory Markers in Ischemic Stroke Patients.

BACKGROUND: Ischemic stroke (IS) usually initiates inflammation and oxidative stress leading to neuronal death. Diabetes and impaired fasting glucose are associated with incidence of cerebrovascular and cardiovascular diseases. METHODS: In the present study, we assessed the relationship of fasting glucose with antioxidative parameters (erythrocyte glutathione peroxidase [GPx] and superoxide dismutase [SOD] activities) and inflammatory markers (high-sensitivity C-reactive protein [hs-CRP] and fibrinogen) in IS patients with and without type 2 diabetes mellitus (T2DM). In addition, we determined factors associated with the risk of IS among these patients. Antioxidative, inflammatory, and lipid parameters were measured in 196 patients with IS (117diabetics and 79 nondiabetics). RESULTS: After adjustment of covariates, multiple logistic regression analysis showed that SOD and GPx significantly decreased the risk of IS among patients with and without T2DM. However, hs-CRP increased the risk of IS. For the diabetic patients, fasting glucose was positively correlated with hs-CRP and fibrinogen and was negatively correlated with GPx and SOD levels. In addition, fasting glucose and hemoglobin A1c or glycosylated hemoglobin (HbA1c) have been shown to increase the risk of IS in diabetic patients. CONCLUSIONS: These data suggest that the antioxidant activity of plasma may be an important factor that provides protection from IS. hs-CRP concentrations can be used as a clinical screening tool to identify individuals with higher risk of IS. Finally, fasting glucose and HbA1c may also be useful indicators for cerebrovascular risk in diabetic patients that may be mediated by low levels of antioxidative defense markers and high inflammation status.

Gene Variant and Level of IL-1ß in Ischemic Stroke Patients With and Without Type 2 Diabetes Mellitus.

Evidence is emerging that inflammation plays a key role in the pathophysiology of ischemic stroke (IS). The aim of this study was to explore, for the first time, the relationship between IL-1ß -31 T/C polymorphism and the risk of ischemic stroke (IS) among patients with type 2 diabetes mellitus (T2DM). One hundred ninety-six patients with IS (117 diabetics and 79 nondiabetics) and 192 controls were recruited to enroll in this study. IL-1ß genotyping was performed by PCR-RFLP technique. After adjusting for sex, age, smoking, obesity, dyslipidemia, and hypertension, there was no significant difference in the distribution of IL-1ß -31 T/C genotypes and allele frequencies between IS patients with or without type 2 diabetes mellitus and control group (p > 0.05). Moreover, a significant positive correlation between serum IL-1ß level and glucose (p1 = 0.044) was showed. In addition, serum levels of IL-1ß were found to be higher among TT genotype carriers than TC and CC genotype carriers in ischemic stroke patients with or without T2DM but these differences were not significant. These results indicate that IL-1ß gene polymorphism might not be a risk factor in the development of ischemic stroke in Tunisian population.

PPAR-ß/δ activation promotes phospholipid transfer protein expression.

The peroxisome proliferator-activated receptor (PPAR)-ß/δ has emerged as a promising therapeutic target for treating dyslipidemia, including beneficial effects on HDL cholesterol (HDL-C). In the current study, we determined the effects of the PPAR-ß/δ agonist GW0742 on HDL composition and the expression of liver HDL-related genes in mice and cultured human cells. The experiments were carried out in C57BL/6 wild-type, LDL receptor (LDLR)-deficient mice and PPAR-ß/δ-deficient mice treated with GW0742 (10mg/kg/day) or a vehicle solution for 14 days. GW0742 upregulated liver phospholipid transfer protein (Pltp) gene expression and increased serum PLTP activity in mice. When given to wild-type mice, GW0742 significantly increased serum HDL-C and HDL phospholipids; GW0742 also raised serum potential to generate preß-HDL formation. The GW0742-mediated effects on liver Pltp expression and serum enzyme activity were completely abolished in PPAR-ß/δ-deficient mice. GW0742 also stimulated PLTP mRNA expression in mouse J774 macrophages, differentiated human THP-1 macrophages and human hepatoma Huh7. Collectively, our findings demonstrate a common transcriptional upregulation by GW0742-activated PPAR-ß/δ of Pltp expression in cultured cells and in mouse liver resulting in enhanced serum PLTP activity. Our results also indicate that PPAR-ß/δ activation may modulate PLTP-mediated preß-HDL formation and macrophage cholesterol efflux.

Matrix metalloproteinase-1 and matrix metalloproteinase-12 gene polymorphisms and the risk of ischemic stroke in a Tunisian population.

Matrix metalloproteinases (MMPs) play an important role in early atherosclerosis, extracellular matrix remodeling, plaque rupture and myocardial infarction. MMP gene polymorphisms contribute to the risk of developing cardiovascular diseases. In this study, we investigated, for the first time, the association between MMP-1-16071G/2G, MMP-12 -82A/G and MMP-12 1082A/G genotypes and haplotypes and the risk of ischemic stroke (IS) among patients with type 2 diabetes mellitus (T2DM). To examine whether these genetic polymorphisms are associated with susceptibility to IS, 196 patients with IS and 192 controls were examined by PCR-based RFLP. When the analyses were adjusted for multiple risk factors, no interaction between T2DM and MMP-1-1607 1G/2G polymorphism on the risk of ischemic stroke was found (p=0.074). However, MMP-12 polymorphisms genotypes were associated with the higher risk of IS in diabetic patients compared with total patients. The -82G-1082G haplotype of MMP-12 polymorphisms was associated with higher risk of ischemic stroke in diabetic patients [AOR=2.33; 95% CI (1.25-3.62), P=0.032]. These findings showed that there was an important joint effect of the MMP-12 polymorphisms and T2DM on the risk of IS and therefore it can be considered as a potential marker of cerebrovascular disorders in diabetic patients.

Effect of the PPARγ C161T gene variant on serum lipids in ischemic stroke patients with and without type 2 diabetes mellitus.

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor involved in the regulation of lipid metabolism, diabetes, obesity, atherogenesis and inflammation. PPARγ genetic variation has been associated with metabolic and cardiovascular diseases. The aim of this study was to explore, for the first time, the relationship between PPARγ C161T polymorphism and the risk of ischemic stroke (IS) among patients with type 2 diabetes mellitus (T2DM). A total of 196 patients with IS (117 diabetics and 79 nondiabetics) and 192 controls were recruited to enroll in this study. PPARγ C161T genotyping was performed by PCR-RFLP technique. The 161T allele as compared with C allele was found to be higher in controls than in IS patients (with or without T2DM). After adjusting for multiple risk factors, the T allele carriers had significantly reduced IS risk (OR=0.575, 95% CI 0.348-0.951, p=0.030) compared to the CC homozygotes which increased significantly the risk in IS patients with T2DM (OR=1.85, 95% CI 1.23-2.62). Moreover, the triglycerides (TG) and ApoB levels in CC homozygote carriers were significantly higher than those in T allele carriers. These results indicate that the C161T of PPARγ may reduce the risk of IS by modulation of adipose metabolism especially TG and ApoB in IS patients with T2DM.

Effect of genetic polymorphism +294T/C in peroxisome proliferator-activated receptor delta on the risk of ischemic stroke in a Tunisian population.

PPARδ +294T/C polymorphism was investigated in diabetics, in normolipidemic healthy controls, in dyslipidemic and nondyslipidemic coronary artery disease patients but never in ischemic stroke patients. The aim of this study was to explore, for the first time, the relationship between the genetic polymorphism of PPARδ and the risk of ischemic stroke among patients with diabetes. The study group consisted of 196 patients with ischemic stroke and 192 controls. Plasma concentrations of total cholesterol, triglycerides, low-, and high-density lipoprotein did not differ significantly between subjects carrying the TT genotype and those carrying the CC/TC genotype in both ischemic stroke patients (with or without diabetes) and control groups. The +294C allele (CC + CT genotypes) as compared with TT genotypes was found to be higher in total ischemic stroke patients than in controls. On the other hand, no interaction between diabetes and PPAR +294T/C polymorphism on the risk of ischemic stroke was found (p = 0.089). The PPARδ +294T/C polymorphism was associated with the risk of ischemic stroke in Tunisian subjects. This polymorphism has no influence on plasma lipoprotein concentrations and body mass index either in healthy subjects or in ischemic stroke patients with or without diabetes both in males and females.