Effect of cocaine on left ventricular function. Relation to increased wall stress and persistence after treatment

MicroRNA-423-5p Mediates Cocaine-Induced Smooth Muscle Cell Contraction by Targeting Cacna2d2

Cocaine abuse increases the risk of atherosclerotic cardiovascular disease (CVD) and causes acute coronary syndromes (ACS) and hypertension (HTN). Significant research has explored the role of the sympathetic nervous system mediating the cocaine effects on the cardiovascular (CV) system. However, the response of the sympathetic nervous system alone is insufficient to completely account for the CV consequences seen in cocaine users. In this study, we examined the role of microRNAs (miRNAs) in mediating the effect of cocaine on the CV system. MiRNAs regulate many important biological processes and have been associated with both response to cocaine and CV disease development. Multiple miRNAs have altered expression in the CV system (CVS) upon cocaine exposure. To understand the molecular mechanisms underlying the cocaine response in the CV system, we studied the role of miRNA-423-5p and its target Cacna2d2 in the regulation of intracellular calcium concentration and SMC contractility, a critical factor in the modulation of blood pressure (BP). We used in vivo models to evaluate BP and aortic stiffness. In vitro, cocaine treatment decreased miR-423-5p expression and increased Cacna2d2 expression, which led to elevated intracellular calcium concentrations and increased SMC contractility. Overexpression of miR-423-5p, silencing of its target Cacna2d2, and treatment with a calcium channel blocker reversed the elevated SMC contractility caused by cocaine. In contrast, suppression of miR-423-5p increased the intracellular calcium concentration and SMC contractibility. In vivo, smooth muscle-specific overexpression of miR-423-5p ameliorated the increase in BP and aortic stiffness associated with cocaine use. Thus, miR-423-5p regulates SMC contraction by modulating Cacna2d2 expression increasing intracellular calcium concentrations. Modulation of the miR-423-5p-Cacna2d2-Calcium transport pathway may represent a novel therapeutic strategy to improve cocaine-induced HTN and aortic stiffness.

Importance of a Risk Stratification Strategy to Identify High-risk Patients Presenting With Cocaine-associated Acute Coronary Syndrome

OBJECTIVE

Current guidelines recommend treating patients with cocaine-associated chest pain, unstable angina, or myocardial infarction similarly to patients with traditional acute coronary syndrome (ACS). Risk stratifying these patients could potentially reduce unnecessary procedures and improve resource utilization.

METHODS

This is a retrospective cross-sectional analysis of 258 patients presenting with cocaine-associated ACS who underwent cardiac catheterization in a community teaching hospital between 2006 and 2015. The primary outcome was the prevalence of acute obstructive coronary artery disease (CAD) requiring percutaneous coronary intervention and coronary artery bypass grafting compared with that of patients with normal coronary or nonobstructive disease.

RESULTS

Of the studied population, 36% had obstructive CAD requiring intervention and 64% were found to have normal coronaries or nonobstructive disease. Significant risk factors for obstructive CAD were older age, history of CAD, diabetes mellitus, dyslipidemia, ST-segment-elevation myocardial infarction, and troponin elevation. A logistic model was developed based on these variables, applied to the studied population, and was found to have 93% sensitivity in predicting the likelihood of obstructive CAD.

CONCLUSIONS

Cardiac catheterization in patients presenting with cocaine-associated ACS may be overutilized. A predictive model based on clinical risk factors may help individualize patient care and reduce unnecessary invasive diagnostic interventions.

Illicit stimulant use in a United States heart failure population presenting to the emergency department (from the Acute Decompensated Heart Failure National Registry Emergency Module)

Illicit stimulant drug use may have a profound clinical impact in acute decompensated heart failure (ADHF). The chronic use of cocaine and methamphetamine may lead to overt cardiomyopathy and ADHF. The Acute Decompensated Heart Failure National Registry Emergency Module (ADHERE-EM) collected data on patients presenting to emergency departments with ADHF at 83 geographically dispersed hospitals in the United States. This registry was queried to determine the rate of self-reported illicit drug use in emergency department patients presenting with ADHF and compare these patients with those without illicit drug use. The registry enrolled 11,258 patients with ADHF with drug use data from January 2004 to March 2006. Of these patients, 594 (5.3%) self-reported current or past stimulant drug use. Compared with nonusers, these patients were more likely to be younger (median age 49.7 vs 76.1 years), to be African American (odds ratio 11.9, 95% confidence interval 9.8 to 14.4), and to have left ventricular ejection fractions <40% (odds ratio 3.4, 95% confidence interval 2.8 to 4.2). Admitted users had no difference in mortality (adjusted odds ratio 0.83, 95% confidence interval 0.25 to 2.72) compared with nonusers. In conclusion, data from ADHERE-EM suggest that a clinically important percentage of patients with ADHF report the use of illicit stimulant drugs. Although these patients are younger with a greater degree of LV dysfunction, they did not have greater risk-adjusted mortality.

Cardiovascular disorders associated with cocaine use: myths and truths

Cocaine produces a pattern of cardiovascular responses that are associated with apparent myocardial ischemia, arrhythmias, and other life-threatening complications in some individuals. Despite recent efforts to better understand the causes of cocaine-induced cardiovascular dysfunction, there remain a number of unanswered questions regarding the specific mechanisms by which cocaine elicits hemodynamic responses. This review will describe the actions of cocaine on the cardiovascular system and the evidence for the mechanisms by which cocaine elicits hemodynamic and pathologic responses in humans and animals. The emphasis will be on experimental data that provide the basis for our understanding of the mechanisms of cardiovascular toxicity associated with cocaine. More importantly, this review will identify several controversies regarding the causes of cocaine-induced cardiovascular toxicity that as yet are still debated. The evidence supporting these findings will be described. Finally, this review will outline the obvious deficits in our current concepts regarding the cardiovascular actions of cocaine in hope of encouraging additional studies on this grave problem in our society.

Cocaine downregulates cardiac SERCA2a and depresses myocardial function in the murine model

Cocaine has been shown to depress myocardial function, which may be linked to abnormal Ca2+ handling by the sarcoplasmic reticulum (SR). To examine whether cocaine affects Ca(2+)-handling proteins and myocardial performance, we injected BALB/c mice with cocaine daily (30 mg/kg, i.p.) for 14 d. Sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) levels, phospholamban (PLB) protein levels, and hemodynamic parameters were measured. After cocaine exposure, myocardial function was significantly decreased both in vivo and in vitro. Also, SERCA2a protein levels were significantly decreased in all cocaine-treated hearts (p < 0.05 compared with saline control). Normalized SERCA2a levels were 1.2 +/- 0.2 (densitometric units) in the cocaine groups (p < 0.05 compared with saline control). However, there was no statistical difference in PLB protein levels between the cocaine and the saline groups. In isolated papillary muscle studies, cocaine did not block the response to extracellular Ca2+ but it did prolong the relaxation time of the muscle. These results indicate that cocaine does not block extracellular Ca2+ entrance across the cell membrane, but that it decreases SERCA2a protein levels. In conclusion, our study demonstrates that cocaine decreases SERCA2a protein levels and depresses myocardial function.

Cocaine related chest pain: are we seeing the tip of an iceberg?

The recreational use of cocaine is on the increase. The emergency nurse ought to be familiar with some of the cardiovascular consequences of cocaine use. In particular, the tendency of cocaine to produce chest pain ought to be in the mind of the emergency nurse when faced with a young victim of chest pain who is otherwise at low risk. The mechanism of chest pain related to cocaine use is discussed and treatment dilemmas are discussed. Finally, moral issues relating to the testing of potential cocaine users will be addressed.

Nitric oxide inhibition intensifies the depressant effect of cocaine on the left ventricular function in anaesthetized pigs

Myocardial ischaemia and left ventricular dysfunction have been described in cocaine users. Whether nitric oxide (NO) inhibition may potentiate the effects of cocaine on coronary circulation and ventricular function is still unknown. In order to test this hypothesis, 38 pentobarbital-anaesthetized pigs were instrumented for systolic blood pressure, coronary blood flow, left ventricular dp/dt, cardiac output, left ventricular end-diastolic and end-systolic lengths and shortening fraction. The pigs were randomized into three groups: control group: i.v. saline (n = 5); group 1: i.v. cocaine, 10 mg kg-1 over 20 min (n = 17); group 2: the same doses of cocaine 30 min after i.c. L-NAME 20 microg/kg min-1 infusion (n = 16). In order to know whether the observed effects were specific of NO inhibition, in five pigs i.c. L-arginine was simultaneously infused with L-NAME, in five pigs i.c. NTG, an endothelial-independent vasodilator, was simultaneously infused with L-NAME before cocaine was administered, and in nine additional pigs the proximal left anterior descending (LAD) flow was reduced to around 20% of the basal value by means of a mechanical occluder before cocaine was administered. Cocaine i.v did not change the coronary blood flow, while it induced a significant reduction in cardiac output, left ventricular dp/dt and shortening fraction (15 +/- 4-8 +/- 4%, P < 0.05). When cocaine was administered after L-NAME infused i.c. during 30 min, a significantly more severe reduction of the shortening fraction (12 +/- 3-4 +/- 2%, P < 0.0001) was induced; this effect was abolished by simultaneous perfusion of L-arginine i.c. NTG. The results when cocaine was administered after the 20% LAD flow reduction by mechanical occluder did not differ from those of cocaine alone. NO inhibition intensifies the cocaine-induced left ventricular dysfunction.