Cocaethylene and heart disease during murine AIDS

Drugs of abuse, immune modulation, and AIDS

Illicit drugs such as amphetamines, cocaine, marijuana, and opiates alter immune function and decrease host resistance to microbes in vitro and in experimental animal models. Effects on the immune system may be mediated indirectly as a result of drug interactions in the central nervous system (CNS) or directly through activation of cognate receptors on various immune cell types. For marijuana and opioids, seven-transmembranal G protein-coupled receptors have been identified in the CNS and in the immune system that may play a functionally relevant role in immune modulation. There is accumulating evidence that sigma(1) receptors play a comparable role in cocaine-mediated alteration of immune responses. A mode by which these exogenously introduced substances affects immunity and host resistance may be by perturbing the balance of Th(1) proinflammatory versus Th(2) anti-inflammatory cytokines and lipid bioeffectors. However, while illicit drugs have been documented to alter immune functions in vitro and in animal models, there is a paucity of controlled longitudinal epidemiological studies that definitively correlate immunosuppressive effects with increased incidence of infections or immune disorders in humans, including infection with the human immunodeficiency virus (HIV) or disease progression to AIDS.

Development of Monoclonal Antibodies Directed Against Cocaine and Cocaethylene: Potential New Tools for Immunotherapy

Cocaine abuse is a major health problem, with the number of overdose-related incidents on a constant increase. Monoclonal antibodies against cocaine and its major toxic metabolite cocaethylene, have been developed for immunotherapeutical neutralization in vivo. A series of monoclonal antibodies with high affinity for cocaethylene and cocaine were obtained. Clones DASm244-4D8A4A4 (4D8) and DASm244-5B3C3C6 (5B3) were selected and fully characterized. The antibodies secreted exhibited 1.40 x 10(8) and 3.69 x 10(7) M(-1) affinity constants for [3H]-cocaine and cocaethylene, respectively. In addition to cocaine, they bound to cocaethylene and did not recognize non-toxic cocaine metabolites. They did not bind to blood cells, indicating that they may be potential tools for cocaine neutralization in vivo in cases of overdose.

Effects of chronic methamphetamine exposure on heart function in uninfected and retrovirus-infected mice

Methamphetamine (MA) increases catecholamine levels, which have detrimental effects on heart function through vasoconstriction, myocardial hypertrophy, and fibrosis. Murine retrovirus infection induces dilated cardiomyopathy (DCM). The present study investigated the cardiovascular effects of chronic MA treatment on uninfected and retrovirus-infected mice. C57BL/6 mice were studied after 12 weeks treatment. The four study groups were (group I) uninfected, MA placebo; (group II) infected, MA placebo; (group III) uninfected, MA treatment; and (group IV) infected and MA treatment. MA injections were given i.p. once a day for 5 days/week with a increasing dose from 15 mg/kg to 40 mg/kg. Left ventricular mechanics were measured in situ a using Millar conductance catheter system for pressure-volume loop analysis. Cardiac pathology was determined with histological analysis. In the uninfected mice, the load independent contractile parameters, pre-load recruitable stroke work (PRSW) and dP/dt(max) vs. Ved, significantly decreased by 32% and 35% in MA treated mice when compared to the saline injected mice. In retrovirus-infected mice, although there were no significant difference in Ees, PRSW, and dP/dt(max) vs. Ved due to MA treatment, they were increased 45%, 15% and 42% respectively when compared to saline treated mice. No further lowered heart function during murine AIDS may be due to the counteraction of the retroviral DCM and the MA induced myocardial fibrosis and hypertrophy (thickening of the ventricular walls). This is supported by increases in the End-diastolic volume (Ved, 38%) and End-systolic volume (Ves, 84%) in the retrovirus-infected saline injected mice, the decreases of 33% and 17% in the uninfected MA-treated mice, but no significant changes in the retrovirus-infected MA treated mice when compared to uninfected saline injected mice. These data suggest that MA induced myocardial cellular changes compensate for retrovirus induced DCM.

Chronic methamphetamine exposure alters immune function in normal and retrovirus-infected mice

Methamphetamine (MA) abuse represents a growing problem in the USA with an increase of sudden death. To evaluate the immune function alterations due to chronic methamphetamine use, we examined C57BL/C mice with LP-BM5 retrovirus infection plus methamphetamine exposure. Mice were randomly assigned to the following groups: placebo, placebo retrovirus-infected, uninfected MA treated and retrovirus-infected MA treated. Placebo, MA-treated groups were intraperitoneally injected with saline, MA, respectively, with a gradually increasing dose from 15 to 40 mg/kg for 12 weeks (5 days/week). Con A- and LPS-induced mitogenesis of splenocytes, cytokine production by splenocytes culture and lipid peroxides in the liver were measured. Heart tissue histopathology was analyzed in all the groups with murine cytomegalovirus (CMV) superinfection. Our data showed that MA treatment significantly decreased production of IL-2 and interferon gamma (IFN-gamma) in uninfected mice but did not further suppress the reduced Th1 cytokines in retrovirus-infected mice. There were no significant effects on cytokines IL-4 and IL-6. However, tumor necrosis factor (TNF-alpha) was significantly increased in both uninfected and infected mice due to MA treatment. Lipid peroxides in liver were significantly increased both in uninfected and retrovirus-infected mice due to MA exposure. Vitamin E levels in liver were significantly decreased in uninfected mice due to MA treatment. CMV superinfection greatly increased the cardiac lesions in retrovirus-infected mice while no significant histopathology changes were detected due to MA treatment. Our data suggest that MA has immunomodulation activity, suppressing Th1 cytokine production and enhancing some Th2 cytokine secretion, as well as increasing lipid peroxides in uninfected mice. The interaction between LP-BM5 and MA remains unclear.