Support for medicinal marijuana has reached an all-time high in the United States. with over 70 percent of Americans in favor of the use of cannabis to lessen the effects of a large number of chronic medical conditions.
People with HIV have long realized that cannabis can ease many HIV-related conditions, including nausea, loss of appetite, depression, weight loss, and neuropathic pain. In addition to treating common symptoms of HIV and side effects of antiretroviral drugs, research indicates that cannabis may help fight HIV itself.
An increasing number of scientific studies, conducted at well-known institutions and published in prominent medical journals, are revealing antiviral effects of cannabis against HIV. These studies detail diverse approaches in measuring favorable effects that cannabis may have in slowing HIV disease progression.
THC in monkeys may lessen HIV’s damage in the gut
During primary infection HIV attacks the gut-associated lymphoid tissue (GALT), where a substantial amount of the immune system is located, hitting CD4 cells hard and early during this process. The initial damage done to GALT is believed to be essential to the progression of HIV disease.
A study funded by the National Institutes of Health and the National Institute on Drug Abuse and published in AIDS Research and Human Retroviruses in 2014 found that THC, the best-known component of cannabis, had a positive effect on GALT in rhesus monkeys that were infected with SIV, the simian version of HIV, after 17 months of receiving THC. Checking the monkeys five months later, researchers from the Louisiana State University Health Sciences Center found that THC produced a generalized decrease in viral load and tissue inflammation and increased production of disease-fighting CD4 and CD8 central memory T cells in GALT.
Blocking HIV’s entry
The effects of cannabis are a result of interactions between cannabinoids and receptors located on many cells, including macrophages (a tissue cell of the immune system) and CD4 cells called cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). Researchers at New York City’s Mount Sinai School of Medicine published data in 2012 demonstrating that stimulation of CB2 with compounds called cannabinoid receptor agonists can block the signaling process between HIV and CXCR4, one of the main types of receptors that allow HIV to enter and infect a cell. CXCR4 is used by HIV during advanced disease and allows for faster disease progression.
By stimulating activation of CB2 with cannabinoid receptor antagonists, Mount Sinai researchers decreased the ability of HIV to infect cells that utilize CXCR4, reducing the frequency of infected cells by 30 to 60 percent.
Cannabinoids may help prevent neurocognitive disorders
Research conducted at Temple University School of Medicine and published in the Journal of Leukocyte Biology suggests that compounds that stimulate CB2 on macrophages may weaken HIV infection. CB2 is the binding site for cannabinoids on macrophages, and stimulation of these receptors, unlike CB1, does not produce the euphoric effects associated with cannabis use.
Neurocognitive disorders are common in people with HIV even in the presence of a strong immune response and suppressed viral load. The virus establishes itself in the central nervous system early on in HIV infection and maintains a stronghold throughout the course of disease. Most antiretroviral medications are unable to cross the blood-brain barrier and thus cannot decrease the level of HIV in the brain, allowing for cognitive damage to continue.
Macrophages are long-lived cells that are targeted by HIV and exist throughout the body. Macrophages are present in the blood and all organs, including in the brain. Some researchers hypothesize that these cells may be key to ongoing replication that creates inflammation, a damaging effect of overstimulation of the immune system. Inflammation can greatly contribute to many non-AIDS-related illnesses, such as neurocognitive disorders, cardiovascular disease, bone disease, and some forms of cancer. The study authors found that anti-inflammatory compounds related to THC bind to CB2, effectively reducing viral replication and inflammation in the brain.
The future of cannabis in HIV
Although Big Pharma is yet to make a serious commitment to the study of cannabis for the treatment of disease, many universities and a small number of biotech companies are investing in the research and development of cannabinoid-based medications. One such company has taken an interest in cannabis and HIV.
Cannabis Science is exploring the use of cannabinoids to treat Kaposi’s sarcoma in people with HIV as well as a potential therapy directed at inhibiting the HIV protein Tat, which is key for viral replication and modulates the expression of genes that regulate a variety of cellular activities. This would be revolutionary for people living with HIV, as chemotherapy, a primary treatment for Kaposi’s sarcoma, is largely unavailable in Africa, which has the highest burden of the disease. A cannabinoid-based antiviral would be cheaper than currently available drugs, greatly decreasing the cost of treating HIV and allowing for increased access to treatment for the nearly 7 million HIV patients around the world who need antiretroviral drugs but do not currently have access to them.