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The power of pot

With Australia set to become a major supplier of medicinal marijuana, Christopher Kelly looks at the arising evidence suggesting weed can help treat HIV in a number of surprising ways.  

Marijuana’s medicinal properties have been well-documented for years. Cannabis is used to alleviate a wide variety of conditions including PTSD, epilepsy, Alzheimer’s, arthritis, autism, osteoporosis, Parkinson’s disease, anxiety and depression, chronic pain, brain disease, multiple sclerosis, and cancer — to name just a few. And now a number of recent studies have indicated that pot may be useful to treat HIV.

Before going any further, a brief explanation on how marijuana works its magic. Cannabis contains cannabinoids which relieve the severe effects of chronic illness by attaching to receptors in the brain, organs, connective tissues, glands, and immune cells. It works to create homeostasis — the maintenance of a balanced internal climate. A normal body will have a healthy endocannabinoid system that feeds receptors and maintains the equilibrium. Somebody with a chronic illness — such as HIV — won’t have receptors that are nourished by the endocannabinoid system. This is where medicinal cannabis can assist in alleviating symptoms such as nausea, neuropathic pain, and appetite and weight loss.

The interrelation between the cannabis plant and the human body is of such complexity that we are only just beginning to understand it. With many countries loosening prohibition, as well as a heightened awareness and acceptance in public opinion — especially among medical professionals — research into the properties and effects of cannabis has reached some amazing breakthrough conclusions. Evidence is emerging that weed can do much more than just alleviate symptoms associated with HIV and ameliorate treatment side effects. A growing body of research suggests the plant’s ingredients may be able to stop the spread of the virus itself by blocking HIV’s entry into cells, curbing chronic inflammation, and helping prevent neurocognitive damage.

Although contrasting data exists, some studies show that people with HIV who had used marijuana had lower viral loads than those who — to quote Bill Clinton— “didn’t inhale”. Another study — observing the effects of cannabis component Denbinobin — appeared to confirm the element’s antiviral activities and therapeutic potential. It’s important to note, however, that these studies were small in scale, meaning there is a need for additional evidence from other samples and settings that include larger numbers of HIV-positive pot users.

Meanwhile, marijuana has been found to slow inflammation in the brain and thus decrease mental decline. While antiretrovirals can’t cross the blood-brain barrier, compounds in cannabis can — reducing inflammation in the process. A study conducted at Michigan State University discovered that the components in marijuana were able to act as anti-inflammatory agents by reducing the number of inflammatory white blood cells — called monocytes — and decreasing the proteins they release in the body. The decrease of cells could slow down, or maybe even stop, the inflammatory process, potentially helping people with HIV maintain their cognitive function for longer.

“The patients who didn’t smoke marijuana had a very high level of inflammatory cells compared to those who did use,” said lead author of the study, Norbert Kaminski (pictured). “In fact, those who used marijuana had levels pretty close to a healthy person not infected with HIV.” Kaminski — who has studied the effects of marijuana on the immune system for almost 30 years — is hopeful that knowing more about this interaction could ultimately lead to new therapeutic agents that could help people with HIV maintain their mental capabilities. “It might not be people smoking marijuana,” said Kaminski. “It might be people taking a pill that has some of the key components found in the marijuana plant that could help.”

It also appears that cannabis — or, more accurately, one of its key ingredients, THC (tetrahydrocannabinol) — can lessen damage in the gut. During early infection, HIV attacks the gut hard as it is home to a substantial amount of the body’s immune system. A “groundbreaking” study has found that THC had a positive effect on the guts of rhesus monkeys infected with SIV (the simian version of HIV).

Researchers found that, not only did THC lead to a decrease in viral load and tissue inflammation, it also bolstered the immune system by increasing production of disease-fighting cells. According to study author, Dr Patricia Molina, “everyone was in awe” of the data. “These findings reveal novel mechanisms that may potentially contribute to cannabinoid-mediated disease modulation,” said Molina. Similar research headed by Molina in 2011 found that SIV-infected monkeys treated with THC had a better chance of surviving than those who went untreated.

Molina’s research was followed up by scientists at the Mount Sinai School of Medicine. Their study found that, by employing cannabinoid receptor antagonists, the signal between HIV and CXCR4 (a receptor that the virus uses to enter the body and destroy immune cells) could be obstructed. The research concluded that by employing cannabinoid antagonists, the spread of HIV could be decreased by up to 60 percent. 

There’s more. In a French study, daily cannabis use was shown to have the potential to have a “protective benefit” on the liver of patients co-infected with hepatitis C and HIV. Conducted by the French National Agency for AIDS Research, the study investigated the impact of marijuana use on the risk of hepatic steatosis (abnormal presence of fat in the liver). Fat in the liver can cause inflammation, scarring and irreversible damage. At its most severe, the condition can progress to liver failure. 

Of the 838 patients enrolled in the study, 14 percent reported using weed every day. Daily use was found to be associated with a 40 percent reduction in the risk of liver fat, which was not found in less frequent cannabis users. However, here’s that caveat again: study author Dr Patrizia Carrieri, of the French National Institute of Health and Medical Research, said that more investigation is needed on the interactions between using psychoactive substances and liver disease progression to confirm any findings. “The data obviously cannot be used to recommend the consumption of any substance or product to HIV and hepatitis C co-infected patients,” she said. “However, it would certainly be useful for clinicians to take into account their patients’ consumption behaviours when making a clinical evaluation.”

Given such intriguing findings, a new US study — the largest of its kind — will further examine marijuana’s effects on people living with HIV. Robert L. Cook, professor of epidemiology at the University of Florida, will lead the US$3.2 study, the long-term goal of which is to provide patients, clinicians and public health authorities with information to guide clinical and safety recommendations for marijuana use. “Marijuana use is increasingly common in persons living with HIV infection. Yet past findings regarding the health impact of marijuana use on HIV have been limited and inconclusive, but we will be looking at a longer view, over several years, and that will be something different about our study over previous studies,” said Cook. 

As for Australian research, there are currently clinical trials underway in Victoria, NSW and Queensland to assess the safety and efficacy of marijuana for medical purposes. However, these studies are focusing on five areas only: palliative care, chemotherapy-induced nausea and vomiting, chronic pain, multiple sclerosis, and epilepsy in paediatric and adult patients. There are no studies examining pot’s effectiveness in specifically treating HIV.

So, for now, when it comes to treating HIV, we’ll have to look to the likes of Cook and colleagues for further insights into the medicinal power of pot. “We do suspect that many people truly do feel better with it and I suspect it’s because of its relationship to inflammation,” said Cook. “HIV virus, if it’s unsuppressed, does cause chronic inflammation in the body and that is usually associated with more rapid ageing, more rapid progression of heart disease, and probably feeling fatigued and tired. If marijuana could suppress some of that chronic inflammation, or at least some parts of marijuana, it really could help people with a chronic virus.” 

THE LOW DOWN

With the exception of one product (nabiximols), medicinal cannabis products in Australia are not available as registered prescription medicines. For a particular product to be registered, a company would need to submit a dossier of evidence on the clinical efficacy, safety and manufacturing quality of a particular medicinal cannabis product to the Therapeutic Goods Administration. 

Medicinal cannabis can only be prescribed by a registered medical practitioner. Before prescribing medicinal cannabis, the doctor will assess each patient individually to decide if the treatment is appropriate for their condition and circumstances. The doctor will look at a patient’s medical history and family health background; the patient's current medications, and any problems with drug dependence and substance abuse, will also be considered. Because medicinal cannabis products are unregistered in Australia, they must be accessed through special pathways available for unapproved medicines.

Registered doctors must also apply and obtain approval to prescribe a medicinal cannabis product to a particular patient under the applicable state or territory laws. Rules relating to medicinal cannabis products vary between states and territories. If both state and TGA requirements are satisfied, then the pharmacy or hospital that the doctor has arranged to supply the imported product can dispense it.

A variety of products are currently available through import from Canada or Europe. These include raw (botanical) cannabis, which for medicinal purposes should be vaporised but not smoked, cannabis extracts in oils, and solvent extracts such as tinctures, and oro-mucosal sprays. Some products for trans-dermal application (patches or topical application of gel or cream) have also been developed. Similar products, manufactured from locally-grown medicinal cannabis, are expected to become available later this year.

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