Cannabinoids: Current and Future Options to Treat Chronic and Chemotherapy-Induced Neuropathic Pain.

“Increases in cancer diagnosis have tremendous negative impacts on patients and their families, and major societal and economic costs. The beneficial effect of chemotherapeutic agents on tumor suppression comes with major unwanted side effects such as weight and hair loss, nausea and vomiting, and neuropathic pain. Chemotherapy-induced peripheral neuropathy (CIPN), which can include both painful and non-painful symptoms, can persist 6 months or longer after the patient’s last chemotherapeutic treatment. These peripheral sensory and motor deficits are poorly treated by our current analgesics with limited effectiveness. Therefore, the development of novel treatment strategies is an important preclinical research focus and an urgent need for patients. Approaches to prevent CIPN have yielded disappointing results since these compounds may interfere with the anti-tumor properties of chemotherapeutic agents. Nevertheless, the first (serotonin noradrenaline reuptake inhibitors [SNRIs], anticonvulsants, tricyclic antidepressants) and second (5% lidocaine patches, 8% capsaicin patches and weak opioids such as tramadol) lines of treatment for CIPN have shown some efficacy. The clinical challenge of CIPN management in cancer patients and the need to target novel therapies with long-term efficacy in alleviating CIPN are an ongoing focus of research. The endogenous cannabinoid system has shown great promise and efficacy in alleviating CIPN in preclinical and clinical studies. In this review, we will discuss the mechanisms through which the platinum, taxane, and vinca alkaloid classes of chemotherapeutics may produce CIPN and the potential therapeutic effect of drugs targeting the endocannabinoid system in preclinical and clinical studies, in addition to cannabinoid compounds diffuse mechanisms of action in alleviation of CIPN.”

https://www.ncbi.nlm.nih.gov/pubmed/31127530

https://link.springer.com/article/10.1007%2Fs40265-019-01132-x

Down-Regulation of Cannabinoid Type 1 (CB1) Receptor and its Downstream Signaling Pathways in Metastatic Colorectal Cancer.

 cancers-logo“Changes in the regulation of endocannabinoid production, together with an altered expression of their receptors are hallmarks of cancer, including colorectal cancer (CRC). Although several studies have been conducted to understand the biological role of the CB1 receptor in cancer, little is known about its involvement in the metastatic process of CRC. The aim of this study was to investigate the possible link between CB1 receptor expression and the presence of metastasis in patients with CRC, investigating the main signaling pathways elicited downstream of CB1 receptor in colon cancer. Fifty-nine consecutive patients, with histologically proven colorectal cancer, were enrolled in the study, of which 30 patients with synchronous metastasis, at first diagnosis and 29 without metastasis. A low expression of CB1 receptor were detected in primary tumor tissue of CRC patients with metastasis and consequently, we observed an alteration of CB1 receptor downstream signaling. These signaling routes were also altered in intestinal normal mucosa, suggesting that, normal mucosa surrounding the tumor provides a realistic picture of the molecules involved in tissue malignant transformation. These observations contribute to the idea that drugs able to induce CB1 receptor expression can be helpful in order to set new anticancer therapeutic strategies.”

https://www.ncbi.nlm.nih.gov/pubmed/31121931

https://www.mdpi.com/2072-6694/11/5/708

Endocannabinoid System in Hepatic Glucose Metabolism, Fatty Liver Disease, and Cirrhosis.

ijms-logo

“There is growing evidence that glucose metabolism in the liver is in part under the control of the endocannabinoid system (ECS) which is also supported by its presence in this organ. The ECS consists of its cannabinoid receptors (CBRs) and enzymes that are responsible for endocannabinoid production and metabolism. ECS is known to be differentially influenced by the hepatic glucose metabolism and insulin resistance, e.g., cannabinoid receptor type 1(CB1) antagonist can improve the glucose tolerance and insulin resistance. Interestingly, our own study shows that expression patterns of CBRs are influenced by the light/dark cycle, which is of significant physiological and clinical interest. The ECS system is highly upregulated during chronic liver disease and a growing number of studies suggest a mechanistic and therapeutic impact of ECS on the development of liver fibrosis, especially putting its receptors into focus. An opposing effect of the CBRs was exerted via the CB1 or CB2 receptor stimulation. An activation of CB1promoted fibrogenesis, while CB2 activation improved antifibrogenic responses. However, underlying mechanisms are not yet clear. In the context of liver diseases, the ECS is considered as a possible mediator, which seems to be involved in the synthesis of fibrotic tissue, increase of intrahepatic vascular resistance and subsequently development of portal hypertension. Portal hypertension is the main event that leads to complications of the disease. The main complication is the development of variceal bleeding and ascites, which have prognostic relevance for the patients. The present review summarizes the current understanding and impact of the ECS on glucose metabolism in the liver, in association with the development of liver cirrhosis and hemodynamics in cirrhosis and its complication, to give perspectives for development of new therapeutic strategies.”

https://www.ncbi.nlm.nih.gov/pubmed/31121839

https://www.mdpi.com/1422-0067/20/10/2516

Targeting Peripheral CB1 Receptors Reduces Ethanol Intake via a Gut-Brain Axis.

Cell Metabolism

“Endocannabinoids acting on the cannabinoid-1 receptor (CB1R) or ghrelin acting on its receptor (GHS-R1A) both promote alcohol-seeking behavior, but an interaction between the two signaling systems has not been explored. Here, we report that the peripheral CB1R inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CB1R, ghrelin peptide or GHS-R1A. JD5037 treatment of alcohol-drinking mice inhibits the formation of biologically active octanoyl-ghrelin without affecting its inactive precursor desacyl-ghrelin. In ghrelin-producing stomach cells, JD5037 reduced the level of the substrate octanoyl-carnitine generated from palmitoyl-carnitine by increasing fatty acid β-oxidation. Blocking gastric vagal afferents abrogated the ability of either CB1R or GHS-R1A blockade to reduce ethanol drinking. We conclude that blocking CB1R in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CB1R blockade may have therapeutic potential in the treatment of alcoholism.”

https://www.ncbi.nlm.nih.gov/pubmed/31105045

https://www.sciencedirect.com/science/article/pii/S1550413119301962?via%3Dihub

Role of the endocannabinoid and endovanilloid systems in an animal model of schizophrenia-related emotional processing/cognitive deficit.

Neuropharmacology

“Studies suggest that the endocannabinoid and endovanilloid systems are implicated in the pathophysiology of schizophrenia.

The Spontaneously Hypertensive Rats (SHR) strain displays impaired contextual fear conditioning (CFC) attenuated by antipsychotic drugs and worsened by pro-psychotic manipulations. Therefore, SHR strain is used to study emotional processing/associative learning impairments associated with schizophrenia and effects of potential antipsychotic drugs.

Here, we evaluated the expression of CB1 and TRPV1 receptors in some brain regions related to the pathophysiology of schizophrenia. We also assessed the effects of drugs that act on the endocannabinoid/endovanilloid systems on the CFC task in SHRs and control animals (Wistar rats – WRs).

These results reinforce the involvement of the endocannabinoid/endovanilloid systems in the SHRs CFC deficit and point to these systems as targets to treat the emotional processing/cognitive symptoms of schizophrenia.”

https://www.ncbi.nlm.nih.gov/pubmed/31103618

https://www.sciencedirect.com/science/article/pii/S0028390819301649?via%3Dihub

Cannabis: From a Plant That Modulates Feeding Behaviors toward Developing Selective Inhibitors of the Peripheral Endocannabinoid System for the Treatment of Obesity and Metabolic Syndrome.

toxins-logo “In this review, we discuss the role of the endocannabinoid (eCB) system in regulating energy and metabolic homeostasis. Endocannabinoids, via activating the cannabinoid type-1 receptor (CB1R), are commonly known as mediators of the thrifty phenotype hypothesis due to their activity in the central nervous system, which in turn regulates food intake and underlies the development of metabolic syndrome. Indeed, these findings led to the clinical testing of globally acting CB1R blockers for obesity and various metabolic complications. However, their therapeutic potential was halted due to centrally mediated adverse effects. Recent observations that highlighted the key role of the peripheral eCB system in metabolic regulation led to the preclinical development of various novel compounds that block CB1R only in peripheral organs with very limited brain penetration and without causing behavioral side effects. These unique molecules, which effectively ameliorate obesity, type II diabetes, fatty liver, insulin resistance, and chronic kidney disease in several animal models, are likely to be further developed in the clinic and may revive the therapeutic potential of blocking CB1R once again.”

https://www.ncbi.nlm.nih.gov/pubmed/31096702

https://www.mdpi.com/2072-6651/11/5/275

CB2 receptor deletion on myeloid cells enhanced mechanical allodynia in a mouse model of neuropathic pain.

 Scientific Reports“Neuropathic pain can develop after nerve injury, leading to a chronic condition with spontaneous pain and hyperalgesia.

Pain is typically restricted to the side of the injured nerve, but may occasionally spread to the contralateral side, a condition that is often referred to as mirror-image pain.

Mechanisms leading to mirror-image pain are not completely understood, but cannabinoid CB2 receptors have been implicated.

In this study, we use genetic mouse models to address the question if CB2 receptors on neurons or on microglia/macrophages are involved.

We conclude that CB2 receptors on microglia and macrophages, but not on neurons, modulate neuropathic pain responses.”

https://www.ncbi.nlm.nih.gov/pubmed/31097758

https://www.nature.com/articles/s41598-019-43858-4

Diverse TRPV1 responses to cannabinoids.

 Publication Cover“Cannabinoid compounds are potential analgesics. Users of medicinal Cannabis report efficacy for pain control, clinical studies show that cannabis can be effective and opioid sparing in chronic pain, and some constituent cannabinoids have been shown to target nociceptive ion channels. Here, we explore and compare a suite of cannabinoids for their impact upon the physiology of TRPV1. The cannabinoids tested evoke differential responses in terms of kinetics of activation and inactivation. Cannabinoid activation of TRPV1 displays significant dependence on internal and external calcium levels. Cannabinoid activation of TRPV1 does not appear to induce the highly permeant, pore-dilated channel state seen with Capsaicin, even at high current amplitudes. Finally, we analyzed cannabinoid responses at nocioceptive channels other than TRPV1 (TRPV2, TRPM8 and TRPA1), and report that cannabinoids differentially activate these channels. On the basis of response activation and kinetics, state-selectivity and receptor selectivity, it may be possible to rationally design approaches to pain using single or multiple cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/31096838

https://www.tandfonline.com/doi/full/10.1080/19336950.2019.1619436

Emerging Class of Omega-3 Fatty Acid Endocannabinoids & Their Derivatives.

Prostaglandins & Other Lipid Mediators

“Cannabinoid receptor activation is involved in homeostatic regulation of the body. These receptors are activated by cannabinoids, that include the active constituents of Cannabis sativa as well as endocannabinoids (eCBs). The eCBs are endogenously synthesized from the omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). In summary, we outline the novel findings regarding a growing class of signaling molecules, omega-3 eCBs, that can control the physiological and pathophysiological processes in the body.” https://www.ncbi.nlm.nih.gov/pubmed/31085370

“Anti-inflammatory ω-3 endocannabinoid epoxides.”  https://www.ncbi.nlm.nih.gov/pubmed/28687674

“Antitumorigenic Properties of Omega-3 Endocannabinoid Epoxides.” https://www.ncbi.nlm.nih.gov/pubmed/29856219

Cannabinoid interactions with ion channels and receptors.

Publication Cover

“Cannabidiol (CBD), the non-psychoactive component of Cannabis sativa, acts on a diverse selection of membrane proteins with promising therapeutic potential in epilepsy and chronic pain. In this review, we will outline the studies that report reproducible results of CBD and other cannabinoids changing membrane channel function, with particular interest on Nav. Nav are implicated in fatal forms of epilepsy and are also associated with chronic pain. This makes Nav potential targets for CBD interaction since it has been reported to reduce pain and seizures. This discovery will not only prompt further research towards CBD’s characterization, but also promotes the application of cannabinoids as potentially therapeutic compounds for diseases like epilepsy and pain.” https://www.ncbi.nlm.nih.gov/pubmed/31088312
https://www.tandfonline.com/doi/full/10.1080/19336950.2019.1615824