Tag Archives: therapies

Cannabinoids and Parkinson’s disease.

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Abstract

“Cannabinoid-based medicines have been proposed as clinically promising therapies in Parkinson’s disease (PD), given the prominent modulatory function played by the cannabinoid signaling system in the basal ganglia. Supporting this pharmacological potential, the cannabinoid signaling system experiences a biphasic pattern of changes during the progression of PD. Thus, early and presymptomatic stages, characterized by neuronal malfunctioning but little evidence of neuronal death, are associated with desensitization/downregulation of CB(1) receptors. It was proposed that these losses may be part of the pathogenesis itself, since they can aggravate different cytotoxic insults which are controlled in part by cannabinoid signals, mainly excitotoxicity but also oxidative stress and glial activation. By contrast, intermediate and, in particular, advanced stages of parkinsonism characterized by a profound nigral degeneration and occurrence of major parkinsonian symptoms (e.g. bradykinesia), are associated with upregulatory responses of CB(1) receptors, possibly CB(2) receptors too, and the endocannabinoid ligands for both receptor types. This would explain the motor inhibition typical of this disease and the potential proposed for CB(1) receptor antagonists in attenuating the bradykinesia typical of PD. In addition, certain cannabinoid agonists have been proposed to serve as neuroprotective molecules in PD, given their well-demonstrated capability to reduce excitotoxicity, calcium influx, glial activation and, in particular, oxidative injury that cooperatively contribute to the degeneration of nigral neurons. However, the potential of cannabinoid-based medicines in PD have been still scarcely studied at the clinical level despite the existence of solid and promising preclinical evidence. Considering the relevance of these preclinical data, the need for finding treatments for motor symptoms that may be alternative to classic dopaminergic replacement therapy, and the lack of efficient neuroprotective strategies in PD, we believe it is of major interest to develop further studies that allow the promising expectations generated for these molecules to progress from the present preclinical evidence towards a real clinical application.”

http://www.ncbi.nlm.nih.gov/pubmed/19839934

Loss of cannabinoid CB1 receptor expression in the 6-hydroxydopamine-induced nigrostriatal terminal lesion model of Parkinson’s disease in the rat.

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Abstract

“The endocannabinoid system is emerging as a potential alternative to the dopaminergic system for the treatment of Parkinson’s disease. Like all emerging targets, validation of this system’s potential for treating human Parkinsonism necessitates testing in animal models of the condition. However, if components of the endocannabinoid system are altered by the induction of a Parkinsonian state in animal models, this could have an impact on the interpretation of such preclinical experiments. This study sought to determine if expression of the CB(1) subtype of cannabinoid receptor is altered in the two most commonly used rat models of Parkinson’s disease. Parkinsonian lesions were induced by stereotaxic injection of 6-hydroxydopamine into the axons (medial forebrain bundle) or terminals (striatum) of the nigrostriatal pathway. On days 1, 3, 7, 14 and 28 post-lesion, rats were sacrificed and brains were processed for tyrosine hydroxylase and CB(1) receptor immunohistochemistry. The CB(1) receptor was expressed strongly in the substantia nigra pars reticulata, minimally overlapping with tyrosine hydroxylase immunoreactivity in the pars compacta. Interestingly, while there was little change in CB(1) receptor expression following axonal lesion, expression of the receptor was significantly reduced following terminal lesion. Loss of CB(1) receptor expression in the pars reticulata correlated significantly with the loss of striatal and nigral volume after terminal lesion indicating this may have been due to 6-hydroxydopamine-induced non-specific damage of striatonigral neurons which are known to express CB(1) receptors. Thus, this result has implications for the choice of model and interpretation of studies used to investigate potential cannabinoid-based therapies for Parkinson’s disease as well as striatonigral diseases such as Huntington’s disease and Multiple Systems Atrophy.”

http://www.ncbi.nlm.nih.gov/pubmed/20097273

Antitumor Effects of Cannabidiol, a Nonpsychoactive Cannabinoid, on Human Glioma Cell Lines

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“Marijuana and its derivatives have been used in medicine for many centuries, and currently there is a renewed interest in the study of the therapeutic effects of cannabinoids…”

“Recently, cannabinoids (CBs) have been shown to possess antitumor properties. Because the psychoactivity of cannabinoid compounds limits their medicinal usage, we undertook the present study to evaluate the in vitro antiproliferative ability of cannabidiol (CBD), a nonpsychoactive cannabinoid compound, on U87 and U373 human glioma cell lines…”

“…the nonpsychoactive CBD was able to produce a significant antitumor activity both in vitro and in vivo, thus suggesting a possible application of CBD as an antineoplastic agent.”

“In conclusion, a cannabinoid-based therapeutic strategy for neural diseases devoid of undesired psychotropic side effects could find in CBD a valuable compound in cancer therapies along with the perspective of evaluating a synergistic effect with other cannabinoid molecules and/or with other chemotherapeutic agents as well as with radiotherapy. Whatever the precise mechanism underlying the CBD effects, the present results suggest a possible application of CBD as a promising, nonpsychoactive, antineoplastic agent.”

http://jpet.aspetjournals.org/content/308/3/838.full

Cannabinoids Inhibit the Vascular Endothelial Growth Factor Pathway in Gliomas

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“Cannabinoids, the active components of Cannabis sativa L. (marijuana), and their derivatives exert a wide array of effects by activating their specific G protein-coupled receptors CB1 and CB2, which are normally engaged by a family of endogenous ligands–the endocannabinoids. Marijuana and its derivatives have been used in medicine for many centuries, and there is currently a renaissance in the study of the therapeutic effects of cannabinoids. Today, cannabinoids are approved to palliate the wasting and emesis associated with cancer and AIDS chemotherapy, and ongoing clinical trials are determining whether cannabinoids are effective agents in the treatment of pain, neurodegenerative disorders such as multiple sclerosis, and traumatic brain injury . In addition, cannabinoid administration to mice and/or rats induces the regression of lung adenocarcinomas, gliomas, thyroid epitheliomas, lymphomas, and skin carcinomas. These studies have also evidenced that cannabinoids display a fair drug safety profile and do not produce the generalized cytotoxic effects of conventional chemotherapies, making them potential antitumoral agents.” 

“Gliomas are one of the most malignant forms of cancer, resulting in the death of affected patients within 1–2 two years after diagnosis. Current therapies for glioma treatment are usually ineffective or just palliative. Therefore, it is essential to develop new therapeutic strategies for the management of glioblastoma multiforme, which will most likely require a combination of therapies to obtain significant clinical results. In line with the idea that anti-VEGF treatments constitute one of the most promising antitumoral approaches currently available, the present laboratory and clinical findings provide a novel pharmacological target for cannabinoid-based therapies.”

“The use of cannabinoids in medicine is limited by their psychoactive effects mediated by neuronal CB1 receptors. Although these adverse effects are within the range of those accepted for other medications, especially in cancer treatment, and tend to disappear with tolerance on continuous use, it is obvious that cannabinoid-based therapies devoid of side-effects would be desirable. As glioma cells express functional CB2 receptors, we used a selective CB2 ligand to target the VEGF pathway. Selective CB2 receptor activation in mice also inhibits the growth and angiogenesis of skin carcinomas.”

“Cannabinoids inhibit tumor angiogenesis…”

“Cannabinoids Inhibit the Vascular Endothelial Growth Factor Pathway in Gliomas”

“Because blockade of the VEGF pathway constitutes one of the most promising antitumoral approaches currently available, the present findings provide a novel pharmacological target for cannabinoid-based therapies.”

http://cancerres.aacrjournals.org/content/64/16/5617.full

The endocannabinoid system as a target for novel anxiolytic and antidepressant drugs.

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“Observational studies in humans suggest that exposure to marijuana and other cannabis-derived drugs produces a wide range of subjective effects on mood tone and emotionality. These observations have their counterpart in animal studies, showing that cannabinoid agonists strongly affect emotional reactivity in directions that vary depending on dose and context. Based on these evidence, the activation of central CB(1) receptor has emerged as potential target for the development of antianxiety and antidepressant therapies…”

http://www.ncbi.nlm.nih.gov/pubmed/19607961

 

Delta-9-tetrahydrocannabinol in cancer chemotherapy: research problems and issues.

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Abstract

“A critical review of the literature assessing the antiemetic efficacy of delta-9-tetrahydrocannabinol (THC) in patients receiving cancer chemotherapy showed considerable inconsistency in results. The equivocal nature of these results partly reflects the difficulty of doing research on antiemetic therapies, but also can be attributed to differences in the adequacy and nature of the research designs, procedures, and assessment instruments that have been used. Several factors were also identified that are seldom studied but may be important in determining whether THC will be effective: patient variables, such as chemotherapy regimen and age; pharmacologic variables, such as drug tolerance, dose, schedule, toxicity, route of administration, and drug interactions; and environmental variables associated with administration setting. The need to differentiate pharmacologically induced from conditioned nausea and vomiting was also pointed out. We believe that THC does have antiemetic efficacy, but the lack of controlled research does not allow precise knowledge of its true effectiveness and toxicity. Well-controlled trials are needed to help answer some of these questions.”

http://www.ncbi.nlm.nih.gov/pubmed/6305249

The cannabinergic system as a target for anti-inflammatory therapies.

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“Habitual cannabis use has been shown to affect the human immune system, and recent advances in endocannabinoid research provide a basis for understanding these immunomodulatory effects. Cell-based experiments or in vivo animal testing suggest that regulation of the endocannabinoid circuitry can impact almost every major function associated with the immune system.

 These studies were assisted by the development of numerous novel molecules that exert their biological effects through the endocannabinoid system. Several of these compounds were tested for their effects on immune function, and the results suggest therapeutic opportunities for a variety of inflammatory diseases such as multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, atherosclerosis, allergic asthma, and autoimmune diabetes through modulation of the endocannabinoid system.”

http://www.ncbi.nlm.nih.gov/pubmed/16918457

Endocannabinoid involvement in endometriosis

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 “Endometriosis is a disease common in women that is defined by abnormal extrauteral growths of uterine endometrial tissue and associated with severe pain. Partly because how the abnormal growths become associated with pain is poorly understood, the pain is difficult to alleviate without resorting to hormones or surgery, which often produce intolerable side effects or fail to help. Recent studies in a rat model and women showed that sensory and sympathetic nerve fibers sprout branches to innervate the abnormal growths. This situation, together with knowledge that the endocannabinoid system is involved in uterine function and dysfunction and that exogenous cannabinoids were once used to alleviate endometriosis-associated pain, suggests that the endocannabinoid system is involved in both endometriosis and its associated pain. Here, using a rat model, we found that CB1 cannabinoid receptors are expressed on both the somata and fibers of both the sensory and sympathetic neurons that innervate endometriosis’s abnormal growths. We further found that CB1 receptor agonists decrease, whereas CB1 receptor antagonists increase, endometriosis-associated hyperalgesia. Together these findings suggest that the endocannabinoid system contributes to mechanisms underlying both the peripheral innervation of the abnormal growths and the pain associated with endometriosis, thereby providing a novel approach for the development of badly-needed new treatments.”

“These findings implicate involvement of the endocannabinoid system in reproductive function and dysfunction. The endocannabinoid system plays a key role in pain mechanisms, and, previously, cannabinoids were long used by women to alleviate dysmenorrhea.”

“Together the findings suggest that the endocannabinoid system is involved in endometriosis and its associated pain via CB1 receptors and innervation of the ectopic growths. Using the rat model, we performed a combination of immunohistochemical and pharmacological studies to test this hypothesis and assess the endocannabinoid system’s potential as a target for new therapies.”

 Summary and conclusions

“These studies in a rat model of endometriosis provide evidence that endocannabinoids might regulate the innervation of the disease’s abnormal growths and that exogenous cannabinoid agents can be effective in reducing endometriosis symptoms. The fact that CB1 receptor expression is greater in the cysts than healthy uterus from the same rats suggests that treatments to activate CB1 receptors (either directly by CB1 agonists or indirectly by increasing relevant endocannabinoid levels) could be developed with minimal effects on uterine function. Although the rat model parallels many aspects of endometriosis in women, there are of course significant differences. However, when considered together with the past history of successful use of cannabinoids for alleviation of gynecological pains, and insofar as findings in rats can model mechanisms of endometriosis-related signs and symptoms, the present results suggest that approaches targeted at the endocannbinoid system represent a promising new direction for developing badly-needed new treatments for pain suffered by women with endometriosis.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2972363/

Cannabinoid receptors as therapeutic targets.

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“CB1 and CB2 cannabinoid receptors are the primary targets of endogenous cannabinoids (endocannabinoids). These G protein-coupled receptors play an important role in many processes, including metabolic regulation, craving, pain, anxiety, bone growth, and immune function

. Cannabinoid receptors can be engaged directly by agonists or antagonists, or indirectly by manipulating endocannabinoid metabolism. In the past several years, it has become apparent from preclinical studies that therapies either directly or indirectly influencing cannabinoid receptors might be clinically useful.

This review considers the components of the endocannabinoid system and discusses some of the most promising endocannabinoid-based therapies.”

http://www.ncbi.nlm.nih.gov/pubmed/16402900

Cannabinoids: potential anticancer agents.

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Abstract

“Cannabinoids – the active components of Cannabis sativa and their derivatives – exert palliative effects in cancer patients by preventing nausea, vomiting and pain and by stimulating appetite. In addition, these compounds have been shown to inhibit the growth of tumour cells in culture and animal models by modulating key cell-signalling pathways. Cannabinoids are usually well tolerated, and do not produce the generalized toxic effects of conventional chemotherapies. So, could cannabinoids be used to develop new anticancer therapies?”

http://www.ncbi.nlm.nih.gov/pubmed/14570037