The emerging role of the endocannabinoid system in the pathogenesis and treatment of kidney diseases.

“Endocannabinoids (eCBs) are endogenous lipid ligands that bind to cannabinoid receptors that also mediate the effects of marijuana.

The eCB system is comprised of eCBs, anandamide, and 2-arachidonoyl glycerol, their cannabinoid-1 and cannabinoid-2 receptors (CB1 and CB2, respectively), and the enzymes involved in their biosynthesis and degradation.

It is present in both the central nervous system and peripheral organs including the kidney.

The current review focuses on the role of the eCB system in normal kidney function and various diseases, such as diabetes and obesity, that directly contributes to the development of renal pathologies.

Normally, activation of the CB1 receptor regulates renal vascular hemodynamics and stimulates the transport of ions and proteins in different nephron compartments. In various mouse and rat models of obesity and type 1 and 2 diabetes mellitus, eCBs generated in various renal cells activate CB1 receptors and contribute to the development of oxidative stress, inflammation, and renal fibrosis.

These effects can be chronically ameliorated by CB1 receptor blockers.

In contrast, activation of the renal CB2 receptors reduces the deleterious effects of these chronic diseases.

Because the therapeutic potential of globally acting CB1 receptor antagonists in these conditions is limited due to their neuropsychiatric adverse effects, the recent development of peripherally restricted CB1 receptor antagonists may represent a novel pharmacological approach in treating renal diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/26280171

Novel Triazolopyrimidine-Derived Cannabinoid Receptor 2 Agonists As Potential Treatment for Inflammatory Kidney Diseases.

“The cannabinoid receptor 2 (CB2) system is described to modulate various pathological conditions, including inflammation and fibrosis.

A series of new heterocyclic small-molecule CB2 receptor agonists were identified from a high-throughput screen…

A significant depletion of the three measured kidney markers indicated a protective role of CB2 receptor activation toward inflammatory kidney damage. Compound 39 was also protective in a model of renal fibrosis.

Oral treatment with 39 at 3 mg kg-1 per day significantly decreased the amount of fibrosis by ∼40 % which was induced by unilateral ureter obstruction.”

http://www.ncbi.nlm.nih.gov/pubmed/26228928

The Endocannabinoid System in Renal Cell: Regulation of Na+ Transport by CB1 Receptors Through Distinct Cell Signaling Pathways.

“The function of the endocannabinoid system (ECS) in the renal tissue is not completely understood.

We studied the effect of compounds modulating the activity of cannabinoid CB receptors on the active reabsorption of Na+ in LLC-PK1 cells.

CONCLUSION AND IMPLICATIONS: ECS is expressed in LLC-PK1 cells. Both TRPV1 and CB1 regulate (Na++K+)-ATPase activity in these cells, and are modulated by lipid and peptide CB1 ligands, which act via different signaling pathways”

.http://www.ncbi.nlm.nih.gov/pubmed/25537261

The endocannabinoid system in renal cell: Regulation of Na+ transport by CB1 receptors through distinct cell signaling pathways.

“The function of the endocannabinoid system (ECS) in the renal tissue is not completely understood. Kidney function is closely related to ion reabsorption in the proximal tubule, the nephron segment responsible for the reabsorption of 70- 80% of the filtrate.

We studied the effect of compounds modulating the activity of cannabinoid CB receptors on the active reabsorption of Na+ in LLC-PK1 cells.

CONCLUSION AND IMPLICATIONS:

ECS is expressed in LLC-PK1 cells. Both CB1 and TRPV1 regulate (Na+ +K+ )-ATPase activity in these cells, and are modulated by lipid and peptide CB1 ligands, which act via different signaling pathways.”

http://www.ncbi.nlm.nih.gov/pubmed/26177675

Renal Effects of Chronic Pharmacological Manipulation of CB2 in Rats with Diet Induced Obesity.

“In diabetic nephropathy CB2 agonism reduces albuminuria and podocyte loss; however the role of CB2 in obesity-related nephropathy is unknown. The aim of this study was to determine the role of CB2 in a model of diet-induced obesity (DIO)…

This study demonstrates that while agonism of CB2 with AM1241 treatment for six weeks does not reduce weight gain in obese rats, it leads to improvements in obesity related renal dysfunction.”

http://www.ncbi.nlm.nih.gov/pubmed/25537025

Alexandros Makriyannis is a professor in the Department of Medicinal Chemistry at Northeastern University, where his research group has synthesized many new compounds with cannabinoid activity.

Is there a legitimate role for the therapeutic use of cannabinoids for symptom management in chronic kidney disease?

“Chronic pain is a common and debilitating symptom experienced in the context of numerous other physical and emotional symptoms by many patients with chronic kidney disease (CKD).

Management of pain with opioids in CKD can be problematic given the prominence of adverse effects of opioids in CKD, which may exacerbate symptoms, such as nausea, anorexia, pruritus, and insomnia, all of which impact negatively on patients’ health-related quality of life.

Novel therapeutic approaches for pain and symptom management in CKD are required.

Recent research in the area of cannabinoids (CBs) is legitimizing the use of cannabis-based medicine.

In this review, we describe the symptom burden borne by patients with CKD and review some of the key basic science and clinical literature to evaluate the potential use of CBs for the management of overall symptom burden in CKD.”

http://www.ncbi.nlm.nih.gov/pubmed/21269798

Cannabinoid receptor 1 is a major mediator of renal fibrosis.

“Chronic kidney disease, secondary to renal fibrogenesis, is a burden on public health.

There is a need to explore new therapeutic pathways to reduce renal fibrogenesis.

To study this, we used unilateral ureteral obstruction (UUO) in mice as an experimental model of renal fibrosis and microarray analysis to compare gene expression in fibrotic and normal kidneys.

The cannabinoid receptor 1 (CB1) was among the most upregulated genes in mice, and the main endogenous CB1 ligand (2-arachidonoylglycerol) was significantly increased in the fibrotic kidney.

Interestingly, CB1 expression was highly increased in kidney biopsies of patients with IgA nephropathy, diabetes, and acute interstitial nephritis. Both genetic and pharmacological knockout of CB1 induced a profound reduction in renal fibrosis during UUO. While CB2 is also involved in renal fibrogenesis, it did not potentiate the role of CB1. CB1 expression was significantly increased in myofibroblasts, the main effector cells in renal fibrogenesis, upon TGF-β1 stimulation.

The decrease in renal fibrosis during CB1 blockade could be explained by a direct action on myofibroblasts. CB1 blockade reduced collagen expression in vitro. Rimonabant, a selective CB1 endocannabinoid receptor antagonist, modulated the macrophage infiltrate responsible for renal fibrosis in UUO through a decrease in monocyte chemoattractant protein-1 synthesis.

Thus, CB1 has a major role in the activation of myofibroblasts and may be a new target for treating chronic kidney disease.”

http://www.ncbi.nlm.nih.gov/pubmed/25760323

Protective role of cannabinoid receptor type 2 in a mouse model of diabetic nephropathy.

“The cannabinoid receptor type 2 (CB2) has protective effects in chronic degenerative diseases. Our aim was to assess the potential relevance of the CB2 receptor in both human and experimental diabetic nephropathy (DN)…

The CB2 receptor is expressed by podocytes, and in experimental diabetes, CB2 beneficialactivation ameliorates both albuminuria and podocyte protein loss, suggesting a protective effect of signaling through CB2 in DN.

In conclusion, our findings may have important implications for DN. The beneficial effect… makes CB2 agonism an attractive new strategy for the treatment of DN. CB2 activation may also positively affect other diabetes-related complications as CB2 agonists may, under certain conditions, delay progression of atherosclerotic lesions and ameliorate diabetes-induced neuropathic pain…

Our study may thus pave the way for future clinical trials on CB2 agonists in humans.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3161308/

Therapeutic potential of cannabinoid medicines.

Drug Testing and Analysis

“Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines.

The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology.

In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/24006213

http://onlinelibrary.wiley.com/doi/10.1002/dta.1529/abstract

The endocannabinoid system and its therapeutic exploitation.

Image result for Nat Rev Drug Discov.

“The term ‘endocannabinoid’ – originally coined in the mid-1990s after the discovery of membrane receptors for the psychoactive principle in Cannabis, Delta9-tetrahydrocannabinol and their endogenous ligands – now indicates a whole signalling system that comprises cannabinoid receptors, endogenous ligands and enzymes for ligand biosynthesis and inactivation. This system seems to be involved in an ever-increasing number of pathological conditions. With novel products already being aimed at the pharmaceutical market little more than a decade since the discovery of cannabinoid receptors, the endocannabinoid system seems to hold even more promise for the future development of therapeutic drugs. We explore the conditions under which the potential of targeting the endocannabinoid system might be realized in the years to come.”  http://www.ncbi.nlm.nih.gov/pubmed/15340387

http://www.nature.com/nrd/journal/v3/n9/full/nrd1495.html