SIV mutations detected in morphine-treated Macaca mulatta following SIVmac239 infection

Opioids and HIV/HCV infection

Since human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same modes of transmission and common risk factors for infection, co-infections with HIV and HCV are frequently found in injection drug users (IDUs). IDUs represent one of the largest reservoirs of HIV as well as HCV in the United States. These two pathogens are also likely to be responsible for the highest infectious disease morbidity and mortality rates among IDUs. IDUs frequently involve the abuse of heroin, the most common abused opiate. Opiates have been suggested to have a cofactor role in the immunopathogenesis of HIV disease, as they have the potential to compromise host immune responses and enhances microbial infections. Although in vitro studies have yielded relatively agreeable data that morphine, the active metabolite of heroin, exacerbate HIV infection/replication, epidemiologic studies as well as in vivo non-human primate investigations on the impact of opiate abuse on HIV disease progression have yielded the conflicting data. Given immunomodulation and immunocompromising effect as well as demonstrated impact to enhance HIV replication in vitro, it is reasonable to believe that opiate abuse is a facilitator in HIV and/or HCV disease progression. However, much remain to be learned about the mechanisms of opiate-mediated broad influence on host immunity and viral expression. Thus, more extensive studies are needed in order to determine the effects of different conditions of opiate abuse and to define the understanding of the role of opiate in modulating HIV and/or HCV disease progression.

Drugs of abuse and HIV infection/replication: implications for mother-fetus transmission

Human immunodeficiency virus (HIV) infection and progression of acquired immunodeficiency syndrome (AIDS) can be modulated by a number of cofactors, including drugs of abuse. Opioids, cocaine, cannabinoids, methamphetamine (METH), alcohol, and other substances of abuse have been implicated as risk factors for HIV infection, as they all have the potential to compromise host immunity and facilitate viral replication. Although epidemiologic evidence regarding the impact of drugs of abuse on HIV disease progression is mixed, in vitro studies as well as studies using in vivo animal models have indicated that drugs of abuse have the ability to enhance HIV infection/replication. Drugs of abuse may also be a risk factor for perinatal transmission of HIV. Because high levels of viral load in maternal blood are associated with increased risk of HIV vertical transmission, it is likely that drugs of abuse play an important role in promoting mother-fetus transmission. Furthermore, because the neonatal immune system differs qualitatively from the adult system, it is possible that maternal exposure to drugs of abuse would exacerbate neonatal immunity defects, facilitating HIV infection of neonate immune cells and promoting HIV vertical transmission. The availability and use of antiretroviral therapy for women infected with HIV increase, there is an increasing interest in determining the impact of drug abuse on efficacy of AIDS Clinical Trials Group (ACTG)-standardized treatment regimens for woman infected with HIV in the context of HIV vertical transmission.

Neuroimmunity, drugs of abuse, and neuroAIDS

It has long been postulated that drugs of abuse may represent significant cofactors in the progression of human immunodeficiency virus (HIV)-induced disease. Both HIV infection and drugs of abuse have significant effect on the immune system as well as on the nervous system. In HIV infection, abnormalities in these systems intersect to lead to a constellation of symptoms known as neuroAIDS. Drugs of abuse may synergize with such damage, acting on immune and/or neural cells. However, definitive epidemiological evidence for such an interaction is lacking. Here we review such studies as well as the use of the nonhuman primate/simian immunodeficiency virus system to investigate the interaction of neuroAIDS with drugs of abuse. Furthermore, recent findings on mechanisms of actions of selected drugs reveal the possibility of protective as well as detrimental effects on the central nervous system damage induced by HIV.

The role of substance abuse in HIV disease progression: reconciling differences from laboratory and epidemiologic investigations

From the onset of the HIV/AIDS epidemic, the use of licit and illicit drugs has been investigated for its potential impact on HIV disease progression. Findings from a large number of laboratory-based studies indicate that drug abuse may exacerbate HIV disease progression; however, epidemiological studies have shown mixed results. This article presents a review of findings from both laboratory-based and epidemiologic investigations. In addition, we provide a careful evaluation of methodological strengths and limitations inherent to both study designs in order to provide a more nuanced understanding of how these findings may complement one another.

Morphine upregulates mu opioid receptors of human and monkey lymphocytes

Opioid receptors of subtypes delta, kappa, and mu similar to those found in brain cells have been identified in immune cells. The current study demonstrates by competitive polymerase chain reaction the treatment of human lymphocytic cells with morphine resulting in an increased amount of gene expression of mu opioid receptors. Antibodies against the MOR-1, the neuronal mu opioid receptor, were used in Western blot analysis of mu proteins and the results revealed a single band of approximately 50 kDa, the intensity of which was increased by morphine treatment. Similar results of mu opioid receptor activation were observed when monkey lymphocytes were treated with morphine. These studies suggest that in addition to causing an immune effect through communication with the neuroendocrine system, the psychoactive drug morphine may modulate immune functions by acting directly on the mu opioid receptors expressed on lymphocytes.