am-1241 and Albuminuria

The endocannabinoid system has been implicated in the pathogenesis of diabetic nephropathy (DN). We investigated the effect of combined therapy with AM6545, a 'peripherally' restricted cannabinoid receptor type 1 (CB1R) neutral antagonist, and AM1241, a cannabinoid receptor type 2 (CB2R) agonist, in experimental DN.. Renal function and structure, podocyte proteins and markers of both fibrosis and inflammation were studied in streptozotocin-induced diabetic mice treated for 14 weeks with vehicle, AM6545, AM1241 and AM6545-AM1241.. Single treatment with either AM6545 or AM1241 alone reduced diabetes-induced albuminuria and prevented nephrin loss both in vivo and in vitro in podocytes exposed to glycated albumin. Dual therapy performed better than monotherapies, as it abolished albuminuria, inflammation, tubular injury and markedly reduced renal fibrosis. Converging anti-inflammatory mechanisms provide an explanation for this greater efficacy as dual therapy abolished diabetes-induced renal monocyte infiltration and M1/M2 macrophage imbalance in vivo and abrogated the profibrotic effect of M1 macrophage-conditioned media on cultured mesangial cells.. 'Peripheral' CB1R blockade is beneficial in experimental DN and this effect is synergically magnified by CB2R activation.

Topics: Albuminuria; Animals; Anti-Inflammatory Agents; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cannabinoids; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Drug Combinations; Drug Evaluation, Preclinical; Male; Mice; Mice, Inbred C57BL; Morpholines; Neutrophil Activation; Podocytes; Pyrazoles

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).. CB2 expression was studied in kidney biopsies from patients with advanced DN, in early experimental diabetes, and in cultured podocytes. Levels of endocannabinoids and related enzymes were measured in the renal cortex from diabetic mice. To assess the functional role of CB2, streptozotocin-induced diabetic mice were treated for 14 weeks with AM1241, a selective CB2 agonist. In these animals, we studied albuminuria, renal function, expression of podocyte proteins (nephrin and zonula occludens-1), and markers of both fibrosis (fibronectin and transforming growth factor-β1) and inflammation (monocyte chemoattractant protein-1 [MCP-1], CC chemokine receptor 2 [CCR2], and monocyte markers). CB2 signaling was assessed in cultured podocytes.. Podocytes express the CB2 receptor both in vitro and in vivo. CB2 was downregulated in kidney biopsies from patients with advanced DN, and renal levels of the CB2 ligand 2-arachidonoylglycerol were reduced in diabetic mice, suggesting impaired CB2 regulation. In experimental diabetes, AM1241 ameliorated albuminuria, podocyte protein downregulation, and glomerular monocyte infiltration, without affecting early markers of fibrosis. In addition, AM1241 reduced CCR2 expression in both renal cortex and cultured podocytes, suggesting that CB2 activation may interfere with the deleterious effects of MCP-1 signaling.. The CB2 receptor is expressed by podocytes, and in experimental diabetes, CB2 activation ameliorates both albuminuria and podocyte protein loss, suggesting a protective effect of signaling through CB2 in DN.

Topics: Albuminuria; Animals; Cannabinoids; Chemokine CCL2; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Disease Models, Animal; Fibronectins; Humans; Kidney Cortex; Membrane Proteins; Mice; Podocytes; Receptor, Cannabinoid, CB2; Transforming Growth Factor beta1