Atorvastatin reduces the proadhesive and prothrombotic endothelial cell phenotype induced by cocaine and plasma from cocaine consumers in vitro.

OBJECTIVE: Cocaine consumption is a risk factor for vascular ischemic complications. Although endothelial dysfunction and accelerated atherosclerosis have been observed in cocaine consumers, the mechanisms underlying their pathogenesis are not fully understood. This study aimed at identifying the effects of atorvastatin in relation to a proadhesive and prothrombotic phenotype induced by cocaine and plasma from chronic cocaine users on endothelial cells. APPROACH AND RESULTS: Human umbilical vein endothelial cells were exposed to either cocaine or platelet-free plasma (PFP) from chronic cocaine consumers in the presence or absence of 10 µmol/L of atorvastatin. Atorvastatin significantly reduced the enhanced platelet adhesion that was induced by cocaine and PFP from chronic cocaine consumers, as well as the release of the von Willebrand factor. Atorvastatin also avoided striking alterations on cell monolayer structure triggered by both stimuli and enhanced NO reduction because of cocaine stimulation through disrupting interactions between endothelial nitric oxide synthase (eNOS) and caveolin-1, thus increasing eNOS bioavailability. Cocaine-increased tissue factor-dependent procoagulant activity and reactive oxygen species generation were not counteracted by atorvastatin. Although monocyte chemoattractant protein-1 levels were not significantly higher than controls either under cocaine or PFP stimulation, atorvastatin completely avoided monocyte chemoattractant protein-1 release in both conditions. Platelets stimulated with cocaine or PFP did not express P-selectin, glycoprotein IIb/IIIa, or CD40L and failed to adhere to resting human umbilical vein endothelial cell. CONCLUSIONS: Cocaine and patient plasma equally induced a proadhesive and prothrombotic phenotype in endothelial cells, except for von Willebrand Factor release, which was only induced by PFP from chronic cocaine consumers. Atorvastatin improved endothelial cell function by reducing cocaine-induced and PFP from chronic cocaine consumer-induced effects on platelet adhesion, cell architecture, and NO production.

Platelet activation in chronic cocaine users: effect of short term abstinence.

Cocaine abuse increases the risk of cardiac and cerebrovascular events, such as myocardial infarction and ischemic stroke. The underlying mechanisms leading to these complications are not fully understood although intravascular thrombus formation has been observed. The aim of this study was to investigate the existence of platelet activation and the effect of short-term abstinence in chronic cocaine consumers. We studied 23 cocaine dependent individuals (aged 20-54 years) who met DSM-IV criteria for cocaine dependence and 20 controls. Samples were obtained at baseline, within 72 h of last drug exposure and after 4 weeks of controlled abstinence. Monocyte-platelet aggregates (MPA) were measured by flow cytometry. Plasma levels of soluble CD40L (sCD40L), Neutrophil-Activating Peptide-2 (NAP-2) and regulated on activation normal T cells expressed and secreted (RANTES) were determined by ELISA. Levels of MPA, sCD40L, NAP-2 and RANTES were significantly higher (all p < 0.05) in cocaine addicts compared to controls at baseline. All the parameters returned to values similar to the control group after 4-weeks' abstinence. Levels of sCD40L and RANTES were associated with an index of intensity of drug consumption (p < 0.02). Our results demonstrate that cocaine use induces platelet activation which is a prominent finding after recent consumption. The persistence over time of this condition may contribute not only to acute thrombotic complications but also to the development of early-onset atherosclerotic process observed in cocaine abusers.

Effect of tamoxifen and retinoic acid on bradykinin induced proliferation in MCF-7 cells.

Chemopreventive approaches for the treatment of breast cancer have been validated clinically and with in vitro studies. The combined action of tamoxifen/all-trans retinoic acid was advantageous in MCF-7 cells, reducing cell proliferation, Bcl-2 and c-Myc protein levels and increasing E-Cadherin protein levels and Gap junctional Intercellular Communication. We further investigated their combined effect in the presence of bradykinin, a pro-inflammatory agent, previously reported to contribute to the proliferation of breast cancer cells. Bradykinin increased MCF-7 cell proliferation, c-Myc levels and ERK1/2 activity. The co-incubation of bradykinin-MCF-7 cells with tamoxifen/all-trans retinoic acid reduced cell proliferation, ERK1/2 activity, as well as Bcl-2, c-Myc, and bradykinin receptor-2 levels, without altering the enhanced E-cadherin levels induced by tamoxifen/all-trans retinoic acid. We showed that the anti-tumoral effect of tamoxifen/all-trans retinoic acid is beneficial in MCF-7 breast cancer cells grown in a bradykinin-pro-mitogenic environment, an effect that might be, at least in part, through the MAPK pathway and B2-bradykinin receptor inhibition.

Changes in regional cerebral blood flow are associated with endothelial dysfunction markers in cocaine-dependent patients under recent abstinence.

OBJECTIVES: Cocaine is a known risk factor for several vascular ischemic events. The underlying mechanisms leading to the complications are not fully understood, although thrombus formation and accelerated atherosclerosis are prominent findings. Evidence of endothelial dysfunction (ED), a key phenomenon in the pathogenesis of atherogenesis, has been demonstrated in cocaine-dependent individuals. Abnormal regional cerebral blood flow (rCBF) is a common finding among chronic cocaine users. The aim of this study was to evaluate whether brain perfusion changes were associated with ED markers in cocaine-dependent individuals. METHODS: Circulating endothelial cells (CECs), soluble intercellular cell adhesion molecule, and the chemokine regulated on activation normal T cells expressed and secreted were measured in 27 DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition) cocaine-dependents patients. Regional cerebral blood flow was assessed using single-photon emission computed tomography at baseline (after recent cocaine consumption) and after 4 weeks of strict abstinence under standard benzodiazepine or antipsychotic therapy. We used statistical parametric mapping analysis to evaluate the covariates. RESULTS: Endothelial cell damage/activation markers were significantly higher in cocaine-dependent individuals after recent consumption and were reduced after 1-month abstinence (P < 0.05). Global rCBF exhibited no significant difference between baseline and after abstinence. When regional perfusion was analyzed in association with ED covariates, significant differences were observed in bilateral cortical areas, including the limbic lobes. CONCLUSIONS: We demonstrated an association between systemic ED markers and rCBF in cocaine-dependent patients. These findings suggest that vascular injury may play a role in the pathogenesis of abnormal rCBF.

Increased RhoA/Rho-Kinase Activity and Markers of Endothelial Dysfunction in Young Adult Subjects with Metabolic Syndrome.

BACKGROUND: Metabolic syndrome, a chronic condition associated with higher risk of cardiovascular diseases, is increasingly prevalent in young adults. Dyslipidemia, proinflammatory cytokines, endothelial dysfunction signs, and RhoA/Rho-kinase (ROCK) activation are considered risk factors of cardiovascular diseases. The occurrence of these factors in young patients with metabolic syndrome but without type 2 diabetes or hypertension has not been fully studied. The objective of this study was to evaluate young subjects with enlarged waist circumference and dyslipidemia but without type 2 diabetes or hypertension,for markers associated with a higher risk of cardiovascular diseases. METHODS: Thirty-two male patients aged 31 ± 1.3 years diagnosed with metabolic syndrome according to the National Cholesterol Education Program Adult Treatment Panel III guide for enlarged waist circumference, elevated triglycerides, and low HDL levels, but with blood pressure and fasting glucose within normal ranges, were evaluated for RhoA/ROCK activity in leukocytes, serum fatty acid methyl esters profile, proinflammatory cytokines, and oxidative stress markers in addition to thrombin generation and biochemical analysis. Age- and gender-matched healthy subjects were equivalently evaluated. RESULTS: Patients showed higher RhoA/ROCK activity, elevated levels of interleukin-6, soluble CD40L, monocyte chemoattractant protein, and high-sensitivity C-reactive protein (P < 0.001) as well as parameters of endogenous thrombin generation potential (P < 0.05) compared with healthy subjects. Increased thiobarbituric acid reactive substances, advanced oxidation protein product, and insulin levels and low nitric oxide biodisponibility (P < 0.001) were also found in patients as compared with controls. Palmitic acid was one of the saturated fatty acids found to be significantly elevated in patients compared with control subjects (P = 0.0087). CONCLUSIONS: Increased markers of cardiovascular risk are already present in young adults with metabolic syndrome but without type 2 diabetes or hypertension.

High glucose increases B1-kinin receptor expression and signaling in endothelial cells.

The loss of endothelial function is the initiating factor in the development of diabetic vascular disease. Kinins control endothelial function by the activation of two receptors: the B2 which is constitutively expressed, and the B1 which is highly induced in pathological conditions. In the present study, we observed that the levels of B1-receptor mRNA and protein are induced in endothelial cells incubated in high glucose. An increase in B1-receptor was also observed in the endothelial layer of aortas, from 4-week diabetic rats. When cells were grown in high glucose, the B1 agonist des-Arg9-BK increased nitrite levels, whereas in normal glucose nitrite levels were unchanged. Nitrite increase was blocked by L-NAME and 1400W indicating the participation of the inducible Nitric Oxide Synthase (iNOS). iNOS protein levels were also increased in high glucose. These results demonstrate the participation of the B1 receptor in the signaling pathways mediated by kinins in high glucose.