Cannabinoid signaling in health and disease.

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“Cannabis sativa has long been used for medicinal purposes.

To improve safety and efficacy, compounds from C. sativa were purified or synthesized and named under an umbrella group as cannabinoids.

Currently, several cannabinoids may be prescribed in Canada for a variety of indications such as nausea and pain.

More recently, an increasing number of reports suggest other salutary effects associated with endogenous cannabinoid signaling including cardioprotection.

The therapeutic potential of cannabinoids is therefore extended; however, evidence is limited and mechanisms remain unclear.

In addition, the use of cannabinoids clinically has been hindered due to pronounced psychoactive side effects.

This review provides an overview on the endocannabinoid system, including known physiological roles, and conditions in which cannabinoid receptor signaling has been implicated.”

Cannabinoids and Cystic Fibrosis

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“Cannabis stimulates appetite and food intake. This property has been exploited to benefit AIDS and cancer patients suffering from wasting disease, by administering the whole plant or its major active ingredient ?-tetrahydrocannabinol (THC). Endogenous cannabinoids (“endocannabinoids”) are found in maternal milk. We have recently shown that endocannabinoids are critical for milk ingestion and survival of newborns because blocking CB1 receptors resulted in death from malnutrition. Lack of appetite resulting in malnutrition is a contributing factor to mortality in many Cystic Fibrosis (CF) patients. It is proposed here for the first time, to administer THC to CF patients. It is hoped that the cannabinoid will alleviate malnutrition and thus help prevent wasting in CF patients. Recent findings suggest that a lipid imbalance (high arachidonic acid/low DHA) is a primary factor in the etiology of CF and that defective CFTR (CF transmembrane conductor regulator) that characterizes the CF condition is responsible for the dysregulation. Endocannabinoids are all fatty acid derivatives. Therefore, it is further proposed here that the CFTR gene product also modulates endocannabinoid synthesis, through regulation of fatty acid biosynthesis. According to this hypothesis, CF patients display decreased levels of endocannabinoids and by elevating these levels, symptoms may improve. Indeed, a number of physiological mechanisms of cannabinoids and endocannabinoids coincide with the pathology of CF. Thus it is suggested that potential benefits from THC treatment, in addition to appetite stimulation, will include antiemetic, bronchodilating, anti-inflammatory, anti-diarrheal and hypo-algesic effects.” https://www.researchgate.net/publication/233294071_Cannabinoids_and_Cystic_Fibrosis

“Cannabinoids and Cystic Fibrosis. A Novel Approach to Etiology and Therapy”  http://www.tandfonline.com/doi/abs/10.1300/J175v02n01_03

Therapeutic potential of cannabinoids in counteracting chemotherapy-induced adverse effects: an exploratory review.

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“Cannabinoids (the active constituents of Cannabis sativa) and their derivatives have got intense attention during recent years because of their extensive pharmacological properties. Cannabinoids first developed as successful agents for alleviating chemotherapy associated nausea and vomiting. Recent investigations revealed that cannabinoids have a wide range of therapeutic effects such as appetite stimulation, inhibition of nausea and emesis, suppression of chemotherapy or radiotherapy-associated bone loss, chemotherapy-induced nephrotoxicity and cardiotoxicity, pain relief, mood amelioration, and last but not the least relief from insomnia. In this exploratory review, we scrutinize the potential of cannabinoids to counteract chemotherapy-induced side effects. Moreover, some novel and yet important pharmacological aspects of cannabinoids such as antitumoral effects will be discussed.”

https://www.ncbi.nlm.nih.gov/pubmed/25504799

Central Aspects of Nausea and Vomiting in GI Disorders.

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“Nausea and vomiting result from continuous interactions among gastrointestinal, central nervous system, and autonomic nervous system. Despite being closely associated, central pathways of nausea and vomiting appear to be at least partly different and nausea is no longer considered only a penultimate step of vomiting. Although our understanding of central pathways of nausea has improved over the last one decade, it is still very basic.

Afferent pathways from gastrointestinal tract via vagus, vestibular system, and chemoreceptor trigger zone project to nucleus tractus solitarius which, in turn, relays the signal to central pattern generator initiating multiple downstream pathways. This central nausea pathway appears to be under constant modulation by autonomic nervous system and cerebral cortex.

There is also some evidence that central pathway of chronic nausea is different from that of acute nausea and closely resembles that of neuropathic pain. This improved understanding has modified the way we can approach the treatment of acute and chronic nausea.

While conventional therapies such as antiemetics (antiserotoninergic, antihistaminic, antidopaminergic) and prokinetics are commonly used to manage acute nausea, they are not as effective in improving chronic nausea.

Recently, neuromodulators such as tricyclic antidepressants, gabapentin, olanzapine, benzodiazepines, and cannabinoids have been shown to have antinausea effect.

There is a need to study the utility of these drugs in managing chronic functional nausea. Improving our understanding of central and peripheral circuitry of nausea will allow us to better utilize the currently available drugs and develop new therapeutic options.”

https://www.ncbi.nlm.nih.gov/pubmed/27734216

Mechanisms of Broad-Spectrum Antiemetic Efficacy of Cannabinoids against Chemotherapy-Induced Acute and Delayed Vomiting.

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“Chemotherapy-induced nausea and vomiting (CINV) is a complex pathophysiological condition and consists of two phases.

The conventional CINV neurotransmitter hypothesis suggests that the immediate phase is mainly due to release of serotonin (5-HT) from the enterochromaffin cells in the gastrointestinal tract (GIT), while the delayed phase is a consequence of release of substance P (SP) in the brainstem. However, more recent findings argue against this simplistic neurotransmitter and anatomical view of CINV.

Revision of the hypothesis advocates a more complex, differential and overlapping involvement of several emetic neurotransmitters/modulators (e.g. dopamine, serotonin, substance P, prostaglandins and related arachidonic acid derived metabolites) in both phases of emesis occurring concomitantly in the brainstem and in the GIT enteric nervous system (ENS).

No single antiemetic is currently available to completely prevent both phases of CINV.

The standard antiemetic regimens include a 5-HT₃ antagonist plus dexamethasone for the prevention of acute emetic phase, combined with an NK1 receptor antagonist (e.g. aprepitant) for the delayed phase. Although NK1 antagonists behave in animals as broad-spectrum antiemetics against different emetogens including cisplatin-induced acute and delayed vomiting, by themselves they are not very effective against CINV in cancer patients.

Cannabinoids such as D⁸-THC also behave as broad-spectrum antiemetics against diverse emetic stimuli as well as being effective against both phases of CINV in animals and patients.

Potential side effects may limit the clinical utility of direct-acting cannabinoid agonists which could be avoided by the use of corresponding indirect-acting agonists.

Cannabinoids (both phyto-derived and synthetic) behave as agonist antiemetics via the activation of cannabinoid CB₁ receptors in both the brainstem and the ENS emetic loci.

An endocannabinoid antiemetic tone may exist since inverse CB₁ agonists (but not the corresponding silent antagonists) cause nausea and vomiting.”

https://www.ncbi.nlm.nih.gov/pubmed/27713384

Successful Treatment of Suspected Cannabinoid Hyperemesis Syndrome Using Haloperidol in the Outpatient Setting.

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“Chronic use of cannabis can result in a syndrome of hyperemesis characterized by cyclical vomiting without any other identifiable causes. Cannabinoid hyperemesis syndrome (CHS) is seldom responsive to traditional antiemetic therapies. Despite frequent nausea and vomiting, patients may be reluctant to discontinue use of cannabis. We report a case of severe, refractory CHS with complete resolution of nausea and vomiting after treatment with haloperidol in the outpatient setting. After review of the literature, we believe this is the first reported successful outpatient treatment of CHS and suggests a potential treatment for refractory patients.”

http://www.ncbi.nlm.nih.gov/pubmed/27597918

“Haloperidol, marketed under the trade name Haldol among others, is a typical antipsychotic medication. Haloperidol is used in the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, nausea and vomiting, delirium, agitation, acutepsychosis, and hallucinations in alcohol withdrawal. It may be used by mouth, as an injection into a muscle, or intravenously.” https://en.wikipedia.org/wiki/Haloperidol

 “Is haloperidol the wonder drug for cannabinoid hyperemesis syndrome? The present report highlights the use of haloperidol as an agent that successfully and safely treats the unrelenting symptoms of CHS.” https://www.ncbi.nlm.nih.gov/pubmed/28052951

“Successful Treatment of Cannabinoid Hyperemesis Syndrome with Topical Capsaicin.” https://www.ncbi.nlm.nih.gov/pubmed/29379817

“Capsaicin (/kæpˈs.ɪsɪn/ (INN); 8-methyl-N-vanillyl-6-nonenamide) is an active component of chili peppers, which are plants belonging to the genus Capsicum.”  https://en.wikipedia.org/wiki/Capsaicin

Preparation and characterization of Δ(9)-tetrahydrocannabinol-loaded biodegradable polymeric microparticles and their antitumoral efficacy on cancer cell lines.

“Cannabinoids present an interesting therapeutic potential as antiemetics, appetite stimulants in debilitating diseases (cancer, AIDS and multiple sclerosis), analgesics, and in the treatment of multiple sclerosis and cancer, among other conditions.

However, despite their high clinical potential, only few dosage forms are available to date.

In this paper, the development of Δ(9)-tetrahydrocannabinol (THC) biodegradable microspheres as an alternative delivery system for cannabinoid parenteral administration is proposed.

As THC has shown therapeutic potential as anticancer drug, the efficacy of the microspheres was tested on different cancer cell lines.

Interestingly, the microspheres were able to inhibit cancer cell proliferation during the nine-day study period.

All the above results suggest that the use of biodegradable microspheres would be a suitable alternative delivery system for THC administration.”

http://www.ncbi.nlm.nih.gov/pubmed/23773072

Cannabinoids for Symptom Management and Cancer Therapy: The Evidence.

“Cannabinoids bind not only to classical receptors (CB1 and CB2) but also to certain orphan receptors (GPR55 and GPR119), ion channels (transient receptor potential vanilloid), and peroxisome proliferator-activated receptors. Cannabinoids are known to modulate a multitude of monoamine receptors. Structurally, there are 3 groups of cannabinoids.

Multiple studies, most of which are of moderate to low quality, demonstrate that tetrahydrocannabinol (THC) and oromucosal cannabinoid combinations of THC and cannabidiol (CBD) modestly reduce cancer pain.

Dronabinol and nabilone are better antiemetics for chemotherapy-induced nausea and vomiting (CINV) than certain neuroleptics, but are not better than serotonin receptor antagonists in reducing delayed emesis, and cannabinoids have largely been superseded by neurokinin-1 receptor antagonists and olanzapine; both cannabinoids have been recommended for breakthrough nausea and vomiting among other antiemetics. Dronabinol is ineffective in ameliorating cancer anorexia but does improve associated cancer-related dysgeusia.

Multiple cancers express cannabinoid receptors directly related to the degree of anaplasia and grade of tumor.

Preclinical in vitro and in vivo studies suggest that cannabinoids may have anticancer activity.

Paradoxically, cannabinoid receptor antagonists also have antitumor activity.

There are few randomized smoked or vaporized cannabis trials in cancer on which to judge the benefits of these forms of cannabinoids on symptoms and the clinical course of cancer. Smoked cannabis has been found to contain Aspergillosis. Immunosuppressed patients should be advised of the risks of using “medical marijuana” in this regard.”

http://www.ncbi.nlm.nih.gov/pubmed/27407130

Dronabinol for chemotherapy-induced nausea and vomiting unresponsive to antiemetics.

“Chemotherapy-induced nausea and vomiting (CINV) is one of the most common symptoms feared by patients, but may be prevented or lessened with appropriate medications.

Several antiemetic options exist to manage CINV. Corticosteroids, serotonin receptor antagonists, and neurokinin receptor antagonists are the classes most commonly used in the prevention of CINV. There are many alternative drug classes utilized for the prevention and management of CINV such as antihistamines, benzodiazepines, anticonvulsants, cannabinoids, and dopamine receptor antagonists.

Medications belonging to these classes generally have lower efficacy and are associated with more adverse effects. They are also not as well studied compared to the aforementioned agents.

This review will focus on dronabinol, a member of the cannabinoid class, and its role in CINV.

Cannabis sativa L. (also known as marijuana) contains naturally occurring delta-9-tetrahydrocannibinol (delta-9-THC). The synthetic version of delta-9-THC is the active ingredient in dronabinol that makes dronabinol an orally active cannabinoid.

Evidence for clinical efficacy of dronabinol will be analyzed in this review as monotherapy, in combination with ondansetron, and in combination with prochlorperazine.”

http://www.ncbi.nlm.nih.gov/pubmed/27274310

Integrating cannabis into clinical cancer care.

“Cannabis species have been used as medicine for thousands of years; only since the 1940s has the plant not been widely available for medical use.

However, an increasing number of jurisdictions are making it possible for patients to obtain the botanical for medicinal use.

For the cancer patient, cannabis has a number of potential benefits, especially in the management of symptoms. Cannabis is useful in combatting anorexia, chemotherapy-induced nausea and vomiting, pain, insomnia, and depression.

Cannabis might be less potent than other available antiemetics, but for some patients, it is the only agent that works, and it is the only antiemetic that also increases appetite.

Inhaled cannabis is more effective than placebo in ameliorating peripheral neuropathy in a number of conditions, and it could prove useful in chemotherapy-induced neuropathy.

A pharmacokinetic interaction study of vaporized cannabis in patients with chronic pain on stable doses of sustained-release opioids demonstrated no clinically significant change in plasma opiates, while suggesting the possibility of synergistic analgesia.

Aside from symptom management, an increasing body of in vitro and animal-model studies supports a possible direct anticancer effect of cannabinoids by way of a number of different mechanisms involving apoptosis, angiogenesis, and inhibition of metastasis.

Despite an absence of clinical trials, abundant anecdotal reports that describe patients having remarkable responses to cannabis as an anticancer agent, especially when taken as a high-potency orally ingested concentrate, are circulating.

Human studies should be conducted to address critical questions related to the foregoing effects.”

http://www.ncbi.nlm.nih.gov/pubmed/27022315