Cannabis and Neurogenesis

Studies present evidence of diminished gray matter in the hippocampus region of cannabis users. Conclusion: protective effects of cannabidiol (CBD)

Study Author(s): Demirakca, Traute;Sartorius, Alexander;Ende, Gabriele;Meyer, Nadja;Welzel, Helga;Skopp, Gisela;Mann, Karl;Hermann, Derik;
Institution: Department of Neuroimaging, Central Institute of Mental Health, J 5, 68159 Mannheim, Germany.


New research has indicated that cannabinoids may hold the key to successfully treating neurogenerative diseases such as Alzheimers Disease. Undertaken by neurologists Veronica Campbell and Steven Fagan of the University of Dublin they were able to explain how the compounds (cannabinoids), which target the endocannabinoid system, are the basis for treating a range of neurodegenerative diseases successfully. The treatment is believed to have very minimal side effects.
Neurodegenerative disease is described as a loss of structure or function of the neurons; that worsens progressively resulting in the death of neurons. Many neurodegenerative diseases, including Parkinson’s, Alzheimer’s, and Huntington’s, occur due to this neurodegenerative process.

Asked to explain how neurodegeneration is linked to the ageing process, Fagan described the connection between people’s age contrasting against their brains, which also experience ageing effects. When a brain is aged, it becomes highly susceptible to many diseases. Fagan explains that as there becomes a larger ageing population with each new year, the incidence of neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease is likewise rising with the increased population of seniors.

Aging naturally leads to changes in the neural chemistry, most notably in the destruction of brain cells. The brain becomes increasingly susceptible to degenerative disorders, such as Parkinson’s and Alzheimer’s diseases. “Current therapies focus on treatment of the symptoms and attempt to delay the progression of these diseases, but there is currently no cure,” Fagan explains. That is until the possibilities of this new treatment come to full realisation.

Fagan’s and Campbell’s research, which builds upon earlier studies by Campbell on Alzheimer’s disease, has been published in the British Journal of Pharmacology. The study suggests that such brain- and age-related conditions can benefit from “the modulation of the endogenous cannabinoid system.”

The researchers reached this conclusion by examining several brains obtained from deceased Alzheimer’s patients. These examinations, coupled with studies on animals, showed that alterations in components of the cannabinoid system occur. Such a study strongly suggests that the cannabinoid system either contributes to, or is altered by, the pathophysiology of Alzheimer’s disease.

From this an important therapeutic target is presented, because alterations in the endocannabinoid system have been detected in patients who are suffering from not only Alzheimer’s disease, but also Parkinson’s and Huntington’s diseases.

Thus, for further study, the neurologists looked at “pharmacological manipulation of the endogenous cannabinoid system, as well as application of phytocannabinoids and synthetic cannabinoids.”

The way that the endocannabinoid can be “manipulated” or modulated to act against the neurodegenerative diseases is through activation by the cannabinoid THC. THC, or tetrahydrocannabinol, is the major psychoactive component of marijuana in the cannabis plant.

Cannabinoids affect cannabinoid receptors, such as receptor CB1, which are found in the brain and the central nervous system. The activation can help to regulate aspects of the brain’s inflammatory response, including halting the release of pro-inflammatory chemicals. These receptors are targets for the phytocannabinoids isolated from the cannabis plant (THC) as well as synthetic preparations.

Specifically, Fagan said that the research group has been looking at dronabinol, a chemical derived from THC (synthesized THC is generally referred to as dronabinol) that stimulates the CB1 receptor.

The research team used dronabinol in a pilot study with Alzheimer’s patients in whom it improved nocturnal motor activity and reduced agitation and aggression, without undesired side effects. From the study, the key aspect appeared to be “the anti-inflammatory and antioxidant properties” of the chemical. This is in keeping with the one factor that links the different neurodegenerative diseases together: neuroinflammation. Fagan surmises that the research “highlights the beneficial effects of cannabinoid treatment.”

The conclusion is in keeping with earlier studies, such as one undertaken at the University College London, that have shown that inflammation and the endocannabinoid system have been linked to another neurodegenerative disease: multiple sclerosis. In addition, some earlier trials have shown that THC could prevent the loss of dopamine neurons in animal models of Parkinson’s disease.

The Irish research is considered important because, hitherto, there were no known treatments that can slow down the progression of brain-associated disorders. British and Irish research is prohibitive in relation to the use of marijuana in human trials. Nonetheless, Fagan is “not averse to trials which look at the use of marijuana and its active ingredients, like THC, in human trials.”

With the beneficial effects of THC highlighted, how do the elderly feel about taking medical marijuana or derivatives? Discussing the issue with some residents at a day center for pensioners in a suburb of north London in the U.K., the reactions were generally positive.

One woman, Patricia Howe, said: “If I can take something to keep my faculties in check, then it sounds like a good thing.” Asked about the difference between a synthetic pill and smoking medical marijuana, she added: “I’ve smoked pot in the past; it did me no harm. If it helped, I’d be willing to try it again.”

A similar reaction was given by Kirsty Froome when asked about a pill: “It sounds like something we should take.” However, in response to the question of inhaling medical marijuana, she said: “I don’t smoke, but I’d be happy to pop a pill – I take enough of them for my other ailments.”

With the idea appearing favorable to people in their sixties and seventies, and with a growing body of research providing increased understanding of the physiological role of endocannabinoids, a therapeutic opportunity appears to be expanding the use of medical cannabis to address several different types of neurological diseases.



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