Cancer research and cannabinoids

Cannabinoids: its role in the control of inflammation, emesis and dysmotility in the gastrointestinal tract

Virginia Thornley, M.D., Neurologist, Epileptologist
@VThornleyMD

August 15, 2018

Introduction

Using medical cannabis in medical practice, one stumbles on incidental anecdotal symptoms that are relieved including effects on the gastrointestinal tract.

With the advent of cannabinoids, more and more conditions are determined to be helped with its use. This includes the conditions affecting the digestive tract. This explores the role the endocannabinoid system has in the homeostatic activities of the gut and the use of cannabinoids in maintaining this. The endocannabinoid system appears to participate in a regulatory role including maintaining motor and sensory function, maintenance of the epithelial layer and regulate the microenvironment.


Endocannabinoid system and GI motility

It appears that CB1 activation ameliorates gastrointestinal motility under normal physiologic conditions whereas the CB2 receptor seems to modulate it under abnormal conditions such as autoimmune or anti-inflammatory conditions (1).

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Endocannabinoid system and pain in the GI tract

Studies have found that there is an interconnection of the TPRV and cannabinoid receptors in affecting visceral pain from stress-related causes and from underlying pathophysiologic conditions. CB1 likely modulates the TPRV receptors causing a reduction of these receptors, whereas the CB2 receptors counteracts the pain effects of mediators of inflammation on the afferent nerves of the visceral organs (2).

Endocannabinoid system and irritable bowel syndrome

Because irritable bowel syndrome has a certain extent of inflammation, this may be a mechanism by which cannabinoids help with the process (2).

Endocannabinoid system and inflammatory conditions of the GI tract

In one study in the animal model, it was found that the endocannabinoid system has an impact the permeability of the GI tract in either a positive or negative fashion. Cannabidiol (CBD) and Tetrahydrocannabinol (THC), 2 of the most well-studied phytocannabinoids, have the capacity to reverse this permeability of the GI tract that is associated with inflammation (3).


Cannabinoids and nausea

Nausea is one of the most well-known and earliest established symptom treated with cannabinoids. Nabilone which has cannabinoids has been used in treating oncologic patients undergoing chemotherapy to ameliorate the nausea that often accompanies this treatment.

In one study of 110 pediatric patients were studied between December 2010 and August 2015 using nabilone. 20% of the patients developed somnolence, euphoria was seen in 3.6% and dizziness was seen in 10%. In 83 patients with chemotherapy causing high rates of emesis, 50% had complete resolution of chemotherapy-induced vomiting. In 23 patients with chemotherapy with moderate rates of emesis, vomiting control was achieved in 53.8% (4).

Role of cannabinoids in the liver

The endicannabinoid system comprises of the CB1 and CB2 receptors, enzymes and endocannabinoids. The CB1 receptor is found to be pro-fibrinogenic in liver cirrhosis and CB2 receptor is found to be anti-fibrinogenic (5).

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This is info only not medical advice.

Reference

1.Duncan, M., Mouihate, A., Mackie, K., Keenan, C.M., Buckley, N.E., Davison, J.S., Patel, K.D., Pittman, Q.J., Sharkey, K.A. Cannabinoid CB2 receptors in the enteric nervous system modulate gastrointesintal contractility in lipopolysaccharide-treated rats. Am J Physiol Gastrointest Liver Physiol. 2008, July, 295 (1):G78-G87

2. Pesce, M., D’Alessandro, A., Borelli, O., Gigli, S., Seguella, L., Cuomo, R., Esposito, G., Sarnelli, G. Endocannabinoid-related compounds in gastrointestinal diseases. J. Cell. Mol. Med 2018, Feb., 22(2):706-715

3. Alhamorumi, A., Wright, K.L., Larvin, M., O’Sullivan, S.E. Cannabinoids mediate opposing effects on inflammation-induced intestinal permeability. Br. J. Pharmacology. 2012, Apr. 165(8):2598-2610

4. Polito, S., MacDonald, T., Romanick, M., Jupp, J., Wiernikpwski, J., Vennetilli, A., Khanna, M., Patel, P., Nin, L., Dupuis, L.L. Safety and efficacy of nabilone for acute chemotherapy-induced vomit in pediatric patients: a multicenter, retrospective review. Pedr. Blood cancer. 2018, Jul. 26:e27374

5. Dibba, P., Li, A.A., Cholankeril, G., Iqbal, U., Gadiparthi, C., Khan, M.A., Kim, D., Ahmed, A. The role of cannabinoids in the setting of cirrhosis. Medicines (Basel). 2018, Jun 9:5(2). pii E52

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Cancer research and cannabinoids

Cannabinoids: mechanisms in gliomas and its possible role in treatment

Virginia Thornley, M.D., Neurologist, Epileptologist
@VThornleyMD

July 18, 2018

Introduction
Glioblastoma multiforme is one of the most malignant types of cancer with a survival rate of less than 5% after 5 years. This may be due to a number of reasons including aggressive angiogenesis, active proliferation of cells and necrosis. In addition, it was found that there are a stem-cell like cells involved which may account for some of its resistance to treatment consisting largely of surgical resection and radiation treatments.

This looks into the role cannabinoids may play in the treatment of gliomas under which glioblastoma multiforme is categorized. Every mechanism is key in providing valuable information in targeting various mechanisms to assist with treatment.

Cannabinoid system and evidence of a role in gliomas

Phytocannabinoids have been identified from the plant cannabis sativa including delta-9-tetraydrocannabinol and cannabidiol. There are 2 significant receptors CB1 receptor and CB2 receptors. Within the endocannabinoid system there are 2 well-studied endocannabinoids, 2-arachidonoylglycerol (2-AG) and anandamide (AEA) and G-related proteins (1). delta-9-tetrahydrocannabinol is a pharmacomimetic of anandamide while cannabidiol is a mimetic of 2-AG. Anandamide is metabolized by fatty acid amide hydrolase or FAAH while 2-AG is metabolized through monoacylglycerol lipase (MAGL).

The receptors are of 2 types. The CB1 receptor is found predominantly in the nervous system in areas subserving pain modulation, memory, and movement. The CB2 receptor is peripherally found in the immune system. The CB2 receptor is found to a lesser extent in other organ systems including adrenal, cardiac, endocrine, pulmonary, gastrointestinal and gynecological organs.  Cannabinoids react with the TRPV receptor or the transient receptor cation channel subfamily V. They can act on G receptors including GPR55 which is thought to influence inhibition of seizures. Other receptors include GPR12, GPR18, and GPR119 (2).

Evidence of a role in gliomas

In glioblastoma multiforme, degrading enzymes of anandamide were found to be reduced with 60% reduction of fatty acid amide hydrolase (FAAH). Anandamide was found to be significantly increased compared to non-tumor tissue. In meningiomas, 2-AG were found to be significantly increased. This points towards elevation of levels of endogenous cannabinoids in the presence of tumor cells which may possibly signal an anti-tumor process by modulating cannabinoid receptor mechanisms (3).

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In pediatric low grade gliomas, it was found that in one cohort there was a spontaneous
involution of the tumors after a subtotal resection. Patients were followed 10 years. Analysis of gene expression and microRNA expression was studied. There was a different set of genes and microRNA expressions discovered in tumors that involuted spontaneously and those that were stable and showed no progression. The CB1 receptor was found to be expressed more abundantly using immunohistochemistry (4). This study suggests that CB1 receptor numbers may corroborate with a better prognosis and suggests a role of endocannabinoids in a more positive prognosis in pediatric low grade glioma.
How cannabinoids play a role in treatment against gliomas

There are various mechanisms by which cannabinoid can modulate the pathogenesis in tumors including proliferation, invasion, cell survival. Cannabinoids are thought to be involved mechanistically in the anti-proliferative, anti-migration and apoptotic effects of tumor cells in gliomas.

Cannabinoids may make tumor cells in gliomas more susceptible to radiation

One study found that cannabinoids may make tumor cells in gliomas more strongly susceptible to irradiation. When heat shock proteins were treated with CBD, they were upregulated. This did not occur in the setting of THC. Heat shock proteins are important in degradation, assembly,  and transcription  factor regulation. They are important in cell survival in the setting of abnormal pH, temperature and inflammation which may be caused by abnormal stability in the cell related to hypoxia, oxidative stress and temperature. Heat shock proteins are associated with resistance of tumor cells to treatment and a poorer prognosis (5). Heat shock proteins can inadvertently promote cancer cell survival, hence, their presence may correlate with a poorer prognosis. Cannabinoids were found to increase reactive oxidative stress leading to an alteration in the expression of HSP’s by increasing it. Increased HSP’s may alter the cytotoxicity of CBD towards cancer cells. By using an HSP inhibitor in conjunction with CBD, there may be better impact of irradiation of tumor cells. In summary, CBD along with HSP inhibitors may make tumor cells in gliomas more vulnerable to tumor irradiation (6).

Cannabinoids causes tumor cell death through apoptotic mechanisms

In one study, cannabinoids were found to have an anti-proliferative effect on tumors. Apoptosis is reduced by mechanisms where cannabinoids stimulate the pro-apoptotic ceramide which subsequently has impact on cell proliferation, differentiation and apoptosis in tumors (7).

In another study, there is supportive evidence that sphingolipid metabolism changes. This causes tetrahydrocannabinol to change the sphingolipid content in the endoplasmic reticulum, autolysosomes and autophagosomes. This contributes towards cell death promotion by autolysosomes which are stimulated by the cannabinoids (8).

Another study confirms that arachidonoylethanolamide (AEA) or anandamide which is the most potent endogenous cannabinoid works through anomalously expressed vanilloid receptor-1 (VR-1) in activating apoptosis in glioma cell lines through this receptor (9). THC is a mimetic of anandamide and may induce apoptosis through this mechanism. This may represent a potential specific molecular mechanism where therapeutic agents may be developed.

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Cannabinoids reduce angiogenesis and proliferation of glioma cell lines

In the human cell glioma cell lines U-87MG and T98G, cannabidiol was found to inhibit the proliferation and cell invasion of these cancer cell lines. These results are significant since aggressive tumors have an ability for normal tissue invasion and proliferation leading to a poor outcome. The doses required for reduction of invasion was less compared to the dosage needed to prevent proliferation. Cannabidiol demonstrated the ability to inhibit different proteins necessary for cell invasion of the 2 cell lines including MMP-9, TIMP-1, TIMP-4, uPA, VEGF and SerpinE1-PAI. Their roles play a significant part in metastasis and vascular proliferation (10). Interestingly, T98G cell lines were found to be delta-9-THC resistant.

Cannabinoids reduce MMP9 which is important in tumor cell invasiveness

MMP are proteases and are increased in the presence of gliomas signaling the invasiveness of the tumor. Cannabinoid inhibition of MMP9 may be the way by which invasiveness of the tumor is reduced. Inhibition of TIMP was also noted in the presence of cannabinoids, which is demonstrated in clinically aggressive gliomas (10).

Cannabinoids inhibits HIF-1 which allows tumor cells to thrive in hypoxic settings

Another significant concept produced by the research is cannabidiol inhibition of HIF1-alpha (or hypoxia induced factor) which is a transcription factor serving a regulatory role in the setting of hypoxia. Hypoxia occurs in fast-growing tumors when the demands for oxygen are outpaced and hypoxia results. In the setting of hypoxia, HIF1-alpha allows tumor cells to thrive in hypoxic conditions through migration, survival and vascular proliferation allowing these tumors to be resistant to chemotherapy (10).

Cannabinoids can modulate mechanistic properties of tumor cells in gliomas

One study demonstrated that cell “stiffness” correlates with the aggressiveness of invasion from tumor cell lines and may represent a mechanistic cell marker to signal invasiveness of a tumor. Cannabinoids can modulate the mechanistic properties of tumors and may be a potential anti-tumor therapeutic target in glioma cell lines(11).

Summary

In summary, cannabinoids are demonstrated to have a role in significant mechanisms involved in tumor activities including anti-proliferation, anti-migration, anti-angiogenesis and anti-survival. Cannabidiol inhibit conditions where transcription factors cause cancer cells to thrive in hypoxic environments which is crucial in the aggressive profile of malignant tumors. Cannabidiol reduces MMP9 significant in invasiveness. Cannabidiol along with HIF inhibitors can make gliomas more radiation susceptible.

The pre-clinical studies are accumulating rapidly which each discovery. Every mechanism elucidated counts towards potential therapeutic targets in gliomas. Pre-clinical studies do not always translate to human studies but the science is gaining headway.

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References
  1. Wang, et al. Quantitative Determination of delta 9-tetrahydrocannabinol, CBG, CBD, their acid precursors and five other neutral cannabinoids by UHPLC-UV-MS. Planta. Med, 2019, Mar., 84 (4):260-266
  2. Landa, et al, “Medical cannabis in the treatment of cancer pain and spastic conditions and options of drug delivery in clinical practice,”Biomed. Pap. Med. Fac. Univ. Palacky Olomouc Czech Repub., 2018, Mar; 162(1):18-25
  3. Petersen, G., Moesgaard, B., Schmid, P.C., Broholm, H., Kosteljanetz, M., Hansen, H.S. Endocannaboinoid metabolism in human glioblastomas and meningiomas compared to human non-tumour brain tissue. J. Neurochem. 2005, Apr., 93 (2):299-309
  4. Sredni, S.T., Huang, C.C., Suzuki, M., Chou, P., Tomita, T. Spontaneous involution of pediatric low-grade gliomas: high expression of cannabinoid receptor 1 (CNR1) at the time of diagnosis may indicate involvement of the endocannabinoid system. Childs Nerv. Sys.t 2016, Nov, 32(11):2061-2067
  5. Calderwood, S.K., Khaleque, A., Sawyer, D.B., Ciocca, D.R., Heat shock proteins in cancer: chaperones to tumorigenesis. Trends in Biochemical Sciences. 2006, Mar. 31(3):164-172 
  6. Scott, K.A., Dennis, J.L., Dalgeish, A.G., Liu, W.M. Inhibiting heat shock proteins can potentiate the cyototoxic effect of cannabidiol in human glioma cells. Anticancer Research. 2015, Nov., 35 (11):5827-583 
  7. Ellert-Miklaszewska, A., Ciechomska, I., Kaminska, B. Cannabinoid signaling in glioma cells. Adv. Exp. Med. Biol. 2013, 986:209-220
  8. Hernandez-Tiedra, s., Fabrias, G., Davila, D., Salanueva, I.J., Casas, J., Montes, L.R., Anton, Z., Garcia-Taboada, E., Salazar-Roa, M., Lorente, M., Nylandsted, J., Armstrong, J., Lopez-Valero, I., McKee, C.S., Serrano-Puebla, A., Garcia-Lopez, R., Gonzale-Martinez, J., Abad, J.L.,, Hanada, K., Boya, P., Goni, F., Guzman, M., Lovat, P., Jaatela, M., Alonso, A., Velasco, G. Dihydroceramide accumulation mediates cytotoxic autophagy of cancer cells via autolysosome destabilization. Autophagy, 2016, Nov. 12 (11):2213-2229
  9. Contassot, E., Wilmotte, R., Tenan, M., Belkouch, M.C., Schuriger, V., de Tribolet, N., Burkhardt, K., Dietrich, P.Y. Arachidonoylethanolamide induces apoptosis of human glioma cells through vanilloid receptor-1. J. Neuropathol. Exp. Neurol. 2004 Sep, 63(9):956-63
  10. Solinas, M., Massi, P., Cinquina, V., Valenti, M., Bolognini, D., Gariboldi, M., Monti, E., Rubino, T., Parolaro, D. Cannabidiol, a non-psychoactive cannabinoid compound, inhibits proliferation and invasion in U87-MG and T98G glioma cells through multitarget effect. PLoS One 2013, 8(10):e76918
  11. Hohmann, T., Grabiec, U., Ghadban, C., Feese, K., Dehghani, F. The influence of biomechanical properties and cannabinoids on tumor invasion. Cell Adh Migr 2017, 11(1):54-67

 

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Alzheimer's disease

Cannabinoids: pre-clinical studies on anti-inflammatory and neuroprotective effects in Alzheimer’s disease

 

Virginia Thornley, M.D., Neurologist, Epileptologist

@VThornleyMD

https://neurologybuzz.com/

June 25, 2018

Introduction

Alzheimer’s disease is not a natural progression of senescence. It is a neurological disorder involving deposition of beta amyloid peptides in senile plaques and accumulation of amyloid precursor proteins within the cerebrum particularly in areas affecting memory and cognition. Current pharmaceutic agents at best can only slow the progression of this disorder. There is no cure. Because it not a devastating illness in that it does not decrease the longevity per se, nonetheless, it is devastating to the patient and family members around him or her.

With the advent of cannabinoids into the pharmaceutic fold, attention is turning towards medical value outside its well-known repertory including anti-inflammatory and neuroprotective properties. Can cannabinoids slow the inflammatory process that is involved in this neurodegenerative condition? This seeks to explore mechanisms by which cannabinoids may play a role in ameliorating the clinical effects seen in Alzheimer’s disease.

Endocannabinoid system

As an overview, the endocannabinoids system is found naturally within the body consisting of endocannabinoids, enzymes and receptors. There are 2 receptors the CB1 receptor which is concentrated in the nervous system and found to a lesser extent in other organ systems and the CB2 receptor which is found mostly in the immune system and in other systems.  Anandamide is an endocannabinoid that exerts its actions on the CB1 receptor, while di-arachidonoylglycerol has a low affinity for the CB1 receptor and interacts with the TPRV or transient receptor potential channels of the vanilloid subtype and the G-coupled receptor family.

Within the cannabis sativa plant are 2 most well-studied phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). The CB1 receptor is where delta-9-tetrahydrocannabinol (THC), a mimetic of Anandamide, interacts and can cause psychoactive effects. Cannabidiol is a mimetic of di-arachidonoylglyerol with a lower affinity to the CB1 receptor where 100 times the amount of CBD is required to achieve the same psychoactivity as THC. When CBD and THC are combined there are less side effects since the CBD acts as a non-competitive allosteric modulator at the  CB1 receptor. When the 2 are combined there is an effect that is increased together compared to when each cannabinoid is taken alone, where the effect is significantly much different. The presence of CBD offsets side effects of THC. Common side effects include agitation, hyperactivity and paranoia.

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Mechanisms

Senile plaques are found to express CB1 and CB2 receptors within the brain in addition to microglial activation markers. The neurons are rich in CB1 receptors but seem to be greatly reduced in microglial activated areas. CB1 receptor expression and G-related coupled protein are reduced in brains with Alzheimer’s disease. Nitration of proteins are enhanced especially in CB1 and CB2 proteins in Alzheimer’s diseased brains. Adding synthetic cannabinoid WIN55-212-2 to rats caused an inhibition of microglial activation and neuron marker loss. Cannabinoids were found to ameliorate neurotoxicity caused by microglial activation (1).

Another study demonstrates the role of cannabinoids on inflammation in the mouse model using synthetic cannabinoids JWH-133 and WIN55.212-2. Cognition and inflammation were studied. FDG uptake on PET scan  was used to assess areas of metabolic uptake. The amyloid precursor protein mice showed poor object recognition. After administration of the JWH compound, cognitive impairments were reversed. There was reduced FDG uptake in the hippocampal areas. No changes were seen using WIN55.212-2. Beta amyloid proteins were significantly reduced in the mice models when cannabinoids were applied. Microglia was elevated in the APP mice which was reduced after cannabinoid administration (2).

In another mouse study, CB2 receptors were at a low level found in the neurons of unmanipulated mice whereas there was a noted increase in the CB2 receptors in mice that underwent chronic inflammation in the microglia surrounding plaques. This suggests that there is an upregulation of CB2 receptors in the presence of pathological inflammation. This may be a potential target in therapeutic agents in the future (3).

In summary

These pre-clinical studies demonstrate a neuroprotective and anti-inflammatory role of cannabinoids on Alzheimer’s disease. The CB2 appears to be upregulated around activated microglial cells around plaques implying a possible therapeutic target for future treatments. While pre-clinical studies are not human trials, elucidating these mechanisms may play a role in the future therapeutic benefits of cannabinoids on Alzheimer’s disease.

https://neurologybuzz.com/
Introduction/Disclaimer

About

 

References

  1. Ramirez, B.G., Blazquez, C., del Pulgar, T.G., Guzman, M., de Ceballos, M.L. Prevention of Alzheimer’s disease pathologyby cannabinoids: neuroprotection mediated by blockade of microglial activation. J. Neurosci. 2005, 25:1904-13
  2. Martín-Moreno, A.M., Brera, B., Spuch, C., Carro, E., García-García, L., Delgado, M., Pozo, M.A., Innamorato, N.G.,  Cuadrado, A., de Ceballos, M.L. Prolonged oral cannabinoid administration prevents neuroinflammation, lowers b-amyloid levels and improves cognitive performance in Tg APP 2576 mice. J. Neuroinflam. 2012, 9:8
  3. Lopez, A., Aparicio, N., Pazos, M.R., Grande, M.T., Barredo-Manso, M.A., Benito-Cuesta, I., Vazquez, C., Amores, M., Ruiz-Perez, G., Garcia-Garcia, E., Beatka, M., Tolon, R.M., Dittel, B.N., Hillard, C.J., Romero, J. Cannabinoid CB2 receptors in the mouse brain: relevance for Alzheimer’s disease. J. Neuroinflam. 2018, May, 15:158
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obsessive compulsive disorder

Cannabinoids in obsessive-compulsive disorder: mechanisms and effectiveness in the animal model

Virginia Thornley, M.D., Neurologist, Epileptologist

June 16, 2018

Introduction

Obsessive-compulsive disorder infamously known to the layman as someone who is excessively interested in keeping their environment clean and orderly. It is a neuropsychiatric condition, where thoughts or actions are repetitive. Usually it involves the complex balance of neurotransmitters within the nervous system so that ideas and actions are carried out in a specific manner. When there is an alteration, repetitive loops occur resulting in repetitive thoughts or reverberating loops of motor activity without the usual negative feedback inhibition. Clinically, this results in intrusive thoughts and repetitive actions that are difficult to control.

Because there is a fine orchestration of the interplay of neurotransmitters, many psychiatric agents have been developed  but success is not always complete.

Medical cannabis is emerging as a treatment option recognized as successfully treating many neuropsychiatric conditions. While large clinical randomized controlled trials are sorely lacking. Scientific research is also necessary to understand the exact science on why t might help with neuropsychiatric disorders.

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Mechanisms of cannabinoids on the CB1 receptor to alleviate repetitive behavior

Anandamide and 2-AG are metabolized by FAAH or fatty acid amide hydrolase and MAGL or monoacyglycerol lipase. FAAH inhibition has been shown to increase anxiolytic effects of endocannabinoid anandamide.

One study sought to seek the effects of FAAH inhibition and MAGL inhibition on the marble burying features of mice (1). Marble burying is a research measure where marble burying is thought to be a sign of anxiety in animals and may correlate with compulsive behavior in mice to alleviate anxiety. Marble burying is an acceptable animal model to demonstrate repetitive behavior and anxiety elicited from mice demonstrating obsessive compulsive disorder (2). Marble burying is not affected by the novelty of the marble or by anxiety. Marble burying is suggested to be a repetitive perseverative type of activity related to digging movements of mice and is a valuable measure in research to evaluate repetitive responses in animals (2).

Benzodiazepines, PF-3845, an FAAH inhibitor and JZL184, a MAGL were found to reduce marble burying activity but did not affect locomotor activity. Delta-9-THC did not reduce marble burying behavior without reducing the locomotor activity (1). In essence, there was significant hypomotility with the marble burying activity.

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Reduction of catabolic enyzymes of endocannabinoids may alleviate anxiety

An antogonist at the CB1 receptor negated the reduction of marble burying activity of FAAH and MAGL but not the benzodiazepine. This suggests that the CB1 receptor has anxiolytic properties. Possible treatments would include targeting of the enzymes that break down cannabinoids making the cannabinoids more available.

Cannabidiol effect on obsessive compulsive behavior in the animal model

Cannabidiol was given to mice using the marble burying test which is an animal model demonstrating compulsive behavior. At 15, 30 and 60mg/kg there was effective reduction of marble burying behavior compared to control mice. This study demonstrated that cannabidiol is effective in reducing repetitive perseverative behavior similar to the conditions in obsessive compulsive disorder (3).

In summary

While most of the preliminary data is entirely preclinical, there is scientific evidence that cannabidiol can reduce obsessive-compulsive behavior in the animal model. The mechanism appears to be at the level of the CB1 receptor. While preclinical data does not always translate into positive human results, this concept is promising. Clinical studies are needed.

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Reference

  1. Kinsey, et al, “Inhibition of endocannabinoid catabolic enzymes elicits anxiolytic-like effects in the marble burying assay,” Pharmacol. Biochem. Behav., 2011 Mar, 98(1)21-7
  2. Thomas, et al, “Marble burying reflects a repetitive and perseverative behavior more than novelty-induced anxiety,” Psychopharmacology, 2010, Jun., 204(2):361-373
  3. Casarotto, et al, “Cannabidiol inhibitory effect on marble-burying behavior:involvement of CB1 receptor,” Behav. Pharmacol, 2010, Jul., 21(4):353-358
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Tourette's Syndrome

Medical cannabis in Tourette’s syndrome: case reports and a small randomized controlled clinical trial

Virginia Thornley, M.D., Neurologist, Epileptologist
June 11, 2018

@VThornleyMD

Introduction
When one hears Tourette’s syndrome the glorified Hollywood impression young person who shouts obscenities comes to mind. It is composed of complex motor or vocal tics generally preceded by a premonitory urge. Vocal tics may consist of coprolalia and echolalia. Motor tics may involve complex actions including copropraxia or simple motor tics. Obsessive compulsive disorder and other neuropsychiatric conditions are often associated with it.

The underlying problem is thought to be related to an imbalance of the neurotransmitters necessary to maintain the fine coordination necessary to avoid excessive motor activity. When that balance is impaired there is less inhibition of motor loop control resulting in reverberating loops and excess movements involving motor groups including muscles controlling speech and body movements. Because the pathophysiology is not entirely clear, these may be some of the most challenging neurological disorders in terms of treatments from a neurological standpoint.

Background on Cannabinoid Mechanisms
With the advent of medical cannabis used in neurological conditions, new indications are discovered. The mechanism is at the level of the endocannabinoid system already inherent within the system. There are 2 receptors, CB1 and CB2. The CB1 receptor is found mostly within the nervous system. The CB2 receptor is mostly in the immune system but is found in other organ systems to a lesser extent. Tetrahydrocannabinol (THC) is a mimetic of Anandamide which works within the endocannabinoid system and has medical properties. THC interacts with the CB1 receptor which is responsible for psychoactive properties most people are familiar with. It is likely at the CB1 receptor where other neurological symptoms are alleviated since this most abundantly found in the nervous system and many neurological symptoms are ameliorated with medical cannabis. Cannabidiol (CBD), which is non-psychoactive, is a pharmacomimetic of 2-AG or diarachidonylglycerol. It is an non-competitive allosteric modulator of the CB1 receptor which alleviates any side effects from THC when they are combined together (1).

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Clinical Reports
There is one report of a patient treated with nabiximol where there was improvement of tics. There was overall improvement in quality of life and global improvement. There was lessening of premonitory urges. Patients feel the premonitory symptoms are more bothersome. In one study anti-psychotics helped ameliorate the motor tics but did not improve the premonitory symptoms (2). Nabiximol was used in this study where 1 puff contained 2.7mg of THC and 2.5mg of CBD. Assessments included the Yale Global Tic Severity Scale (YGTSS), Tourette’s Syndrome Symptom LIst (TSSL), Modified Rush Video Tic Scale, Premonitory Urge for Tic Scale, Global Clinical Impairment, Visual Analogue Scale for satisfaction for the GTS-Quality of Life. The study showed the best results in the quality of life in terms of alleviating premonitory urges. Larger clinical trials are needed to further this study (2).

In a recent case report, THC (trademark Sativex) was used with success to treat a patient using 10.8mg THC and 10mg CBD daily. Yale Global Tic Severity Scale (YGTSS) and the Original Rush Video Tic Scale were used as measures of evaluation. The results demonstrated effective use of THC in combination with THC for treatment in medically refractory patients (5).

In one single dose, cross over study in 12 patients and a randomized trial in 24 patients spanning 6 weeks was performed (3). The study demonstrated that THC reduces tics without any disruption in cognitive function. Neuropsychological impairment was not seen (3).

In the randomized double blinded placebo-controlled clinical trial of 24 patients, THC of up to 10mg was used in the treated cohort over 6 weeks. Measures used included the Tourette’s Syndrome Clinical Global Impression Scale (TS-CGI), Shapiro Tourette Syndrome Severity Scale (STSS), the Yale Global Tic Severity Scale (YGTSS), Tourette Syndrome Symptom List (TSSL) and the videotape based rating scale. Patients were rated at visits 1 for baseline, visits 3-4 during treatment and visits 5-6 after withdrawal. There was a significant difference between both groups. There was a significant reduction in motor tics, vocal tics and obsessive compulsive disorder. No significant adverse cognitive effects were noted (4).

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More randomized controlled clinical studies are necessary
While there may be a paucity of large clinical trials of the use of medical cannabis in Tourette’s syndrome, tetrahydrocannabinol is a potential therapeutic agent in a neurological disorder where treatment options are very limited and often times unsuccessful. Adverse side effects can preclude treatment using conventional pharmaceutic agents.

While large randomized controlled clinical trials are necessary in providing standard of care, tetrahydrocannabinol has emerged as a potential treatment option used by clinicians who are on the frontlines of treating this debilitating disorder.

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Reference
1. Laprairie, et al, “Cannabidiol is a negative allosteric modulator of the cannabinoid CB1 receptor,” Br. J. Pharmacology, 2015, Oct., 172(20):4790-4805
2. Kanaan, et al, “Significant tic reduction in an otherwise treatment-resistant patient with Gilles de la Tourette syndrome following treatment with nabiximol,: Brain Science, 2017, Apr., 7 (5):47
3. Muller-Vahl,”Cannabinoids reduce symptoms of Tourette’s syndrome,” Expert Opin Pharmacother., 2003, Oct., 4(10):17-1725
4. Muller-Vahl, “Delta-9-Tetrahydrocannabinol (THC) is effective in the treatment of tics in Tourette syndrome: a 6 week randomized trial,” J. Clin Psychiatry, 2003, Apr., 64 (4):459-65
5. Trainor, “Severe motor and vocal tics controlled with Sativex®,” Australas Psychiatry, 2016, Dec, 24 (6):541-544

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