Effects of direct high sodium exposure at endothelial cell migration.

The present study aimed to test the hypothesis that high sodium affects the migratory phenotype of endothelial cells (EC) and investigates mechanisms involved independently of hemodynamic factors. Cell migration was evaluated by Wound-Healing at conditions: High Sodium (HS; 160 mM) and Control (CT; 140 mM). O2- production was evaluated by DHE. NADPH oxidase activity was determined by chemiluminescence assay. Expression of adhesion molecules was analyzed by RT-PCR. Shear Stress was performed using a rhythmic shake. Nitric oxide production was measured by Griess reaction. HS-induced impairment in EC migration while both Candesartan and DPI prevented it. HS increased NADPH oxidase activity, which was blocked by Candesartan. Also, HS increased O2- production that was inhibited by Candesartan. HS decreased adhesion molecules expression via ROS (Integrin Alpha 5, Integrin Beta 1, Integrin Beta 3, VE-Cadherin and PECAM) and via AT1R (PECAM). The nitric oxide production induced by shear stress was decreased after EC exposure to HS while both Candesartan and DPI prevented it. Conclusion: This study demonstrated that HS reduced EC migration by AT1R and ROS derived from NADPH Oxidase and mitochondria. The HS reduction in adhesion molecules expression modulated by ROS and AT1R may help to explain the impairment in migration capacity. Also, HS affected EC functionality by reducing their nitric oxide production in response to shear stress.

Lipopolysaccharide exposure modulates the contractile and migratory phenotypes of vascular smooth muscle cells.

INTRODUCTION: Sepsis survivors are at higher risk for cardiovascular events. Lipopolysaccharide (LPS) activates Toll-like receptor 4 (TLR4) in sepsis. Activation of TLR4 modulates vascular smooth muscle cells (VSMCs) phenotype and contributes to cardiovascular changes after sepsis. AIM: Investigate changes in VSMCs phenotype caused by LPS-induced TLR4 activation. METHODS: Rat VSMCs were incubated with LPS. Two incubation conditions were used in cell contraction and migration assays: acute stimulation - LPS stimulus was initiated at the beginning of the assay and maintained throughout; and preconditioning - LPS stimulation was applied prior to the assay then discontinued. Nitric oxide (NO) production, mRNA expression of cytokines and phenotype markers, and interleukin (IL)-6 production were evaluated. KEY FINDINGS: LPS increased gene expression of IL-1ß, IL-6, TNFα and MCP-1 (p < .001), of secretory phenotype markers collagen and vimentin (p < .0479) and of the contractile marker smooth muscle 22α (SM22α) (p = .0067). LPS exposure increased IL-6 secretion after 24 and 48 h (p < .0001), and NO at 8 and 24 h (p < .0249) via inducible nitric oxide synthase (iNOS), as demonstrated by a decrease in NO after incubation with aminoguanidine. Acute stimulation with LPS reduced migration and contraction in a NO-dependent manner, while preconditioning with LPS increased both in an IL-6-dependent manner. SIGNIFICANCE: LPS affects VSMCs by modulating their secretory, contractile and migratory phenotypes. LPS acute stimulation of VSMCs promoted a NO-dependent reduction in migration and contraction, while preconditioning with LPS promoted IL-6-dependent increases in migration and contraction, evidencing that VSMCs can present phenotype modifications that persist after sepsis, thereby contributing to postsepsis cardiovascular events.

Estrogen receptor α polymorphism is associated with dementia in a Brazilian cohort.

The growth of the elderly population is a worldwide phenomenon and it is associated with chronic diseases, including dementia. In this scenario, the present study aimed to evaluate a possible association of estrogen receptor α polymorphisms with dementia in a Brazilian cohort. The subject sample was divided into two groups, control (n = 105) and case (n = 73), according to analysis of two predictive dementia tests (MMSE and CDR). The genotyping for the ERα PvuII (c.454-397T>C, rs2234693) and XbaI (c.454-351A>G, rs9340799) polymorphisms were performed by polymerase chain reaction-restriction fragment length polymorphism. The ERα PvuII pp genotype was associated with higher odds ratio for dementia (OR = 3.42, 95% CI = 1.33-8.77, p = 0.01, in a model including covariates. A linear regression model identified significant associations of the ERα PvuII genotypes (independent variable) with CDR scale (dependent variable), ß = 0.26 and p = 0.001. In conclusion, estrogen receptor α PvuII polymorphism is associated with dementia in a Brazilian cohort. This finding may be useful for the identification of a possible set of significant genetic and clinical biomarkers for better understanding pathophysiology, early diagnosis and management of dementia.

Dipeptidyl peptidase-4 inhibition prevents vascular dysfunction induced by ß-adrenergic hyperactivity.

Chronic stimulation of the ß-adrenergic sympathetic system induces vascular dysfunction which is associated with increased inflammatory cytokines production. A recently proposed therapy to control vascular injury through inflammatory processes involves inhibition of the enzyme dipeptidyl peptidase-IV (DPP4). The present study investigates whether the inhibition of DPP4 prevents the increase in inflammatory markers induced by isoproterenol and restores endothelial function in vivo and in vitro. Male Wistar rats were divided into four groups: vehicle (VHC), an isoproterenol-treated group (ISO), a sitagliptin-treated group (SITA), and an isoproterenol and sitagliptin-treated group (ISO + SITA). The ISO group exhibited significantly increased contractile responses to phenylephrine associated with reduced endothelial participation, which was totally prevented by DPP4 inhibition. In vitro incubation with isoproterenol had no effect on vascular smooth muscle cells, however isoproterenol increased the activity of DPP4 and the expression of inflammatory cytokines in endothelial cells, while sitagliptin reduced the level of cytokines to basal level. In conclusion, we have shown that beta-adrenergic receptor activation can increase DPP4 activity, which was associated with vascular dysfunction and cytokine expression in endothelial cells. The important role of DPP4 was further supported by sitagliptin, which reversed vascular changes induced by isoproterenol in vivo and in vitro.