Category Archives: Kidney Disease

Do Endocannabinoids Regulate Glucose Reabsorption in the Kidney?

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“Diabetic nephropathy (DN), a distinct manifestation of diabetic kidney disease, affects approximately 30% of patients with diabetes. While most attention has been focused on glomerular changes related to DN, there is growing evidence that tubulopathy is a key feature in the pathogenesis of this disease. The renal proximal tubule cells (RPTCs) are particularly sensitive to the deleterious effect of chronic hyperglycemia. However, the cellular changes that control the dysfunction of the RPTCs are not fully understood.

Controlling glucose reabsorption in the proximal tubules via inhibition of glucose transporters (GLUT) has emerged as a promising therapeutic in ameliorating DN.

Overactivation of the renal endocannabinoid (eCB) system via the cannabinoid-1 receptor (CB1R) contributes to the development of DN, and its blockade by globally acting or peripherally restricted CB1R antagonists has been shown to ameliorate renal dysfunction in different murine models for diabetes. Recently, we have utilized various pharmacological and genetic tools to show that the eCB/CB1R system contributes to the development of DN via regulating the expression, translocation, and activity of the facilitative GLUT2 located in the RPTCs.

These findings have the potential to be translated into therapy, and support the rationale for the preclinical development of novel renal-specific CB1R and/or GLUT2 inhibitors for the treatment of DN.”

https://www.ncbi.nlm.nih.gov/pubmed/30636250

https://www.karger.com/Article/FullText/494512

Targeted inhibition of the type 2 cannabinoid receptor is a novel approach to reduce renal fibrosis.

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Kidney International Home

“The cannabinoid receptor type 2 (CB2) is a G protein-coupled seven transmembrane receptor that transmits endogenous cannabinoid signaling. The role of CB2 in the pathogenesis of kidney injury and fibrosis remains poorly understood.

Here we demonstrate that CB2 was induced, predominantly in kidney tubular epithelium, in various models of kidney disease induced by unilateral ureteral obstruction, adriamycin or ischemia/reperfusion injury.

By using in silico screening and medicinal chemistry modifications, we discovered a novel compound, XL-001, that bound to CB2 with high affinity and selectivity and acted as an inverse agonist. Delayed administration of XL-001 was also effective in ameliorating kidney fibrosis and inflammation.

Thus, CB2 is a pathogenic mediator in kidney fibrosis and targeted inhibition with the novel inverse agonist XL-001 may provide a strategy in the fight against fibrotic kidney diseases.”

 https://www.ncbi.nlm.nih.gov/pubmed/30093080
https://www.kidney-international.org/article/S0085-2538(18)30397-1/fulltext

The impact of Cannabidiol treatment on regulatory T-17 Cells and neutrophil polarization in Acute Kidney Injury.

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 American Journal of Physiology-Renal Physiology 0 0 cover image

“Hallmark features of acute kidney injury (AKI) include mobilization of immune and inflammatory mechanisms culminating in tissue injury. Emerging information indicates heterogeneity of neutrophils with pro- and anti-inflammatory functions (N1 and N2, respectively). Also, regulatory T-17 (Treg17) cells curtail Th-17-mediated pro-inflammatory responses. However, the status of Treg17 cells and neutrophil phenotypes in AKI are not established.

Further, cannabidiol exerts immunoregulatory effects but its impact on Treg17 cells and neutrophil subtypes is not established. Thus, we examined the status of Treg17 cells and neutrophil subtypes in AKI and determined whether cannabidiol favors regulatory neutrophils and T cells accompanied with renoprotection.

Importantly, cannabidiol treatment preserved ψm, reduced cell death and KIM-1 accompanied by restoration of N1 and N2 imbalance and preservation of Treg17 cells while decreasing Th-17 cells. The ability of cannabidiol to favor development of Treg17 cells was further established using functional mixed lymphocytic reaction. Subsequent studies showed higher renal blood flow and reduced serum creatinine in cannabidiol-treated IRI animals.

Collectively, our novel observations establish that renal IRI causes neutrophil polarization in favor of N1 and also reduces Treg17 cells in favor of Th-17, effects that are reversed by cannabidiol treatment accompanied with significant renoprotection.”

https://www.ncbi.nlm.nih.gov/pubmed/29897289

https://www.physiology.org/doi/10.1152/ajprenal.00112.2018

Ischemia/Reperfusion Model Impairs Endocannabinoid Signaling and Na+/K+ ATPase Expression and Activity in Kidney Proximal Tubule Cells.

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“LLC-PK1 cells, an immortalized epithelial cell line derived from pig renal proximal tubules, express all the major players of the endocannabinoid system (ECS) such as CB1, CB2 and TRPV1 receptor, as well as the main enzymes involved in the biosynthesis and degradation of the major endocannabinoids named 2-arachidonoylglycerol, 2-AG and anandamide, AEA.

Here we investigated whether the damages caused by ischemic insult either in vitro using LLC-PK1 cells exposed to antimycin A (an inductor of ATP-depletion) or in vivo using Wistar rats in a classic renal ischemia and reperfusion (IR) protocol, lead to changes in AEA and 2-AG levels, as well as altered expression of genes from the main enzymes involved in the regulation of the ECS.

Our data show that the mRNA levels of CB1 receptor gene were downregulated, while the transcript levels of monoacylglycerol lipase (MAGL), the main 2-AG degradative enzyme, are upregulated in LLC-PK1 cells after IR model. Accordingly, IR was accompanied by a significant reduction in the levels of 2-AG and AEA, as well as of the two endocannabinoid related molecules, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in LLC-PK1 cells. In kidney cortex homogenates, the AEA levels were selectively significantly decreased. In addition, we found that both the in vitro and in vivo model of IR caused a reduction in the expression and activity of the Na+/K+ATPase. These changes were reversed by the CB1/CB2 agonist WIN55,212, in a CB1-receptor dependent manner on LLC-PK1 IR model.

In conclusion, the ECS and Na+/K+ ATPase are down-regulated following IR model in LLC-PK1 cells and rat kidney. We suggest that CB1 agonists might represent a potential strategy to reverse the consequences of IR injury in kidney tissues.”

https://www.ncbi.nlm.nih.gov/pubmed/29890144

https://www.sciencedirect.com/science/article/pii/S0006295218302132

Involvement of the CB2 cannabinoid receptor in cell growth inhibition and G0/G1 cell cycle arrest via the cannabinoid agonist WIN 55,212-2 in renal cell carcinoma.

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“The anti-tumor properties of cannabinoids have been investigated in many in vitro and in vivo studies. Many of these anti-tumor effects are mediated via cannabinoid receptor types 1 and 2 (CB1 and CB2), comprising the endocannabinoid system (ECS).

In this study, we investigated the ECS based on CB 1 and CB 2 receptor gene and protein expression in renal cell carcinoma (RCC) cell lines. In view of their further use for potential treatments, we thus investigated the roles of CB1 and CB2 receptors in the anti-proliferative action and signal transduction triggered by synthetic cannabinoid agonists [such as JWH-133 and WIN 55,212-2 (WIN-55)] in RCC cell lines.

RESULTS:

The CB1 and CB2 genes expression was shown by real-time PCR and flow cytometric and western blot analysis indicating a higher level of CB2 receptor as compared to CB1 in RCC cells. Immunocytochemical staining also confirmed the expression of the CB1 and CB2 proteins. We also found that the synthetic cannabinoid agonist WIN-55 exerted anti-proliferative and cytotoxic effects by inhibiting the growth of RCC cell lines, while the CB2 agonist JWH-133 did not. Pharmacologically blocking the CB1 and CB2 receptors with their respective antagonists SR141716A and AM-630, followed by the WIN-55 treatment of RCC cells allowed uncovering the involvement of CB2, which led to an arrest in the G0/G1 phase of the cell cycle and apoptosis.

CONCLUSIONS:

This study elucidated the involvement of CB2 in the in vitro inhibition of RCC cells, and future applications of CB2agonists in the prevention and management of RCC are discussed.

In summary, our study shows the involvement of CB2 receptor in the in vitro inhibition of RCC cells. This knowledge will be useful to unravel the future applications of CB2receptor and its agonists in the prevention and management of RCC.”

 https://www.ncbi.nlm.nih.gov/pubmed/29792186
https://bmccancer.biomedcentral.com/articles/10.1186/s12885-018-4496-1

The role of cannabinoid signaling in acute and chronic kidney diseases.

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 Image result for Kidney Int. “The endogenous cannabinoids anandamide and 2-arachidonoylglycerol bind to the cannabinoid receptors of type 1 and 2. These receptors are also the binding sites for exogenous, both natural and synthetic, cannabinoids that are used for recreation purposes.

Until recently, cannabinoids and cannabinoid receptors have attracted little interest among nephrologists; however, a full endocannabinoid system (ECS) is present in the kidney and it has recently emerged as an important player in the pathogenesis of diabetic nephropathy, drug nephrotoxicity, and progressive chronic kidney disease.

This newly established role of the ECS in the kidney might have therapeutic relevance, as pharmacological modulation of the ECS has renoprotective effects in experimental animals, raising hope for future potential applications in humans.

In addition, over the last years, there has been a number of reported cases of acute kidney injury (AKI) associated with the use of synthetic cannabinoids that appear to have higher potency and rate of toxicity than natural Cannabis. This poorly recognized cause of renal injury should be considered in the differential diagnosis of AKI, particularly in young people.

In this review we provide an overview of preclinical evidence indicating a role of the ECS in renal disease and discuss potential future therapeutic applications.”

https://www.ncbi.nlm.nih.gov/pubmed/29706358

Chronic Pain Treatment With Cannabidiol in Kidney Transplant Patients in Uruguay.

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Transplantation Proceedings Home

“Chronic pain is a major therapeutic problem in kidney transplant patients owing to nephrotoxicity associated with nonsteroidal antiiflammatory drugs.

Benefits in chronic pain treatment with cannabidiol (CBD) have been reported.

This study assesses the effect, safety, and possible drug interactions in kidney transplant patients treated with CBD for chronic pain.

RESULTS:

We assessed 7 patients with a mean age of 64.5 years (range, 58-75 years). CBD initial dose was 100 mg/d, CBD dose reduction to 50 mg/d has been done on day 4 to patient 1 for persistent nausea. Tacrolimus dose reduction in patient 3 was undertaken on days 4, 7, and 21 owing to persisting elevated levels (even before CBD) and itching, and on day 21 in patient 5. Tacrolimus levels decreased in patient 2 but were normal in the control 1 week later. Patients on cyclosporine were stable. Adverse effects were nausea, dry mouth, dizziness, drowsiness, and intermittent episodes of heat. CBD dose decrease was required in 2 patients. Two patients had total pain improvement, 4 had a partial response in the first 15 days, and in 1 there was no change.

CONCLUSIONS:

During this follow-up, CBD was well-tolerated, and there were no severe adverse effects. Plasma levels of tacrolimus were variable. Therefore, longer follow-up is required.”

https://www.ncbi.nlm.nih.gov/pubmed/29579828

http://www.transplantation-proceedings.org/article/S0041-1345(17)30962-4/fulltext

Marijuana Use and Renal Function Among US Adults.

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The American Journal of Medicine Home

“In recent years, the number of states that have legalized medical marijuana or retail sales has increased, bringing potential changes of marijuana use pattern among the general population. However, health effects of acute and chronic marijuana use on many relevant health outcomes, including renal function, remain largely unexamined.

In this study, we aimed to assess the association between recent and past marijuana use and renal function.

CONCLUSIONS:

We did not observe any clinically significant association between current or past self-reported marijuana use and measures of kidney function.”

https://www.ncbi.nlm.nih.gov/pubmed/29291894

http://www.amjmed.com/article/S0002-9343(17)31193-2/fulltext

“No link between current or previous marijuana use and kidney disease, say researchers” https://www.sciencedaily.com/releases/2018/03/180301125051.htm

“Marijuana Doesn’t Seem to Harm the Kidneys” https://www.webmd.com/mental-health/addiction/news/20180306/marijuana-doesnt-seem-to-harm-the-kidneys

“”Our research provides some reassuring evidence suggesting that there is no detrimental effect of infrequent, relatively light use of marijuana on kidney function among healthy adults under age 60,”” https://consumer.healthday.com/general-health-information-16/illicit-drugs-news-217/marijuana-doesn-t-seem-to-harm-the-kidneys-731632.html

“Pot Won’t Harm Healthy Young People’s Kidneys, Study Suggests”  https://www.medicinenet.com/script/main/art.asp?articlekey=206375

Cannabinoid Receptors in Diabetic Kidney Disease.

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 Current Diabetes Reports

“The purpose of this review is to examine and summarize studies assessing the relevance of the endocannabinoid system (ECS) in diabetic kidney disease (DKD).

Endocannabinoids and endocannabinoid receptors of type 1 (CB1R) and of type 2 (CB2R) are present in the normal kidney. Expression of CB1R and CB2R is altered in experimental DKD.

Studies in experimental animals and cultured kidney cells show a beneficial effect of peripheral CB1R blockade and CB2R activation in DKD and an even greater efficacy of a combined treatment.

Preclinical studies confirm that both CB1R and CB2R are implicated in the pathogenesis of DKD and may represent novel targets for treatment.”

https://www.ncbi.nlm.nih.gov/pubmed/29399721

https://link.springer.com/article/10.1007%2Fs11892-018-0975-7 

Selective cannabinoid 2 receptor stimulation reduces tubular epithelial cell damage following renal ischemia-reperfusion injury.

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Journal of Pharmacology and Experimental Therapeutics “Ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), which is an increasing problem in the clinic and has been associated with increased rates of mortality. Currently, therapies to treat AKI are not available, so identification of new targets which, upon diagnosis of AKI, can be modulated to ameliorate renal damage is essential.

In this study, a novel cannabinoid receptor 2 (CB2) agonist, SMM-295, was designed, synthesized, and tested in vitro and in silico.

These data suggests that selective CB2 receptor activation could be a potential therapeutic target in the treatment for AKI.”

https://www.ncbi.nlm.nih.gov/pubmed/29187590

http://jpet.aspetjournals.org/content/early/2017/11/29/jpet.117.245522