ABSTRACT
Underlying pathogenic mechanisms in chronic kidney disease (CKD) include chronic inflammation, oxidant stress, and matrix remodeling associated with dysregulated nuclear factor-κ B, nuclear factor-κ B, and SMAD signaling pathways, respectively. Important cytoprotective mechanisms activated by oxidative inflammatory conditions are mediated by nitrated fatty acids that covalently modify proteins to limit inflammation and oxidant stress. In the present study, we evaluated the effects of chronic treatment with CXA-10 (10-nitro-9(E)-octadec-9-enoic acid) in the uninephrectomized deoxycorticosterone acetate-high-salt mouse model of CKD. After 4 weeks of treatment, CXA-10 [2.5 millligrams per kilogram (mpk), p.o.] significantly attenuated increases in plasma cholesterol, heart weight, and kidney weight observed in the model without impacting systemic arterial blood pressure. CXA-10 also reduced albuminuria, nephrinuria, glomerular hypertrophy, and glomerulosclerosis in the model. Inflammatory MCP-1 and fibrosis (collagen, fibronectin, plasminogen activator inhibitor-1, and osteopontin) renal biomarkers were significantly reduced in the CXA-10 (2.5 mpk) group. The anti-inflammatory and antifibrotic effects, as well as glomerular protection, were not observed in the enalapril-treated group. Also, CXA-10 appears to exhibit hormesis as all protective effects observed in the low-dose group were absent in the high-dose group (12.5 mpk). Taken together, these findings demonstrate that, at the appropriate dose, the nitrated fatty acid CXA-10 exhibits anti-inflammatory and antifibrotic effects in the kidney and limits renal injury in a model of CKD.
Subject(s)
Cytoprotection/drug effects , Desoxycorticosterone Acetate/pharmacology , Kidney Diseases/chemically induced , Kidney Diseases/pathology , Kidney/drug effects , Kidney/pathology , Nitro Compounds/pharmacology , Oleic Acids/pharmacology , Salts/adverse effects , Animals , Desoxycorticosterone Acetate/pharmacokinetics , Kidney/metabolism , Kidney Diseases/metabolism , Male , Mice , Nitro Compounds/pharmacokinetics , Oleic Acids/pharmacokinetics , Oxidative Stress/drug effects , Tissue DistributionABSTRACT
BACKGROUND: Obesity is characterized by the accumulation of fat in the liver and other tissues, leading to insulin resistance. We have previously shown that a specific inhibitor of glucosylceramide synthase, which inhibits the initial step in the synthesis of glycosphingolipids (GSLs), improved glucose metabolism and decreased hepatic steatosis in both ob/ob and diet-induced obese (DIO) mice. Here we have determined in the DIO mouse model the efficacy of a related small molecule compound, Genz-112638, which is currently being evaluated clinically for the treatment of Gaucher disease, a lysosomal storage disorder. METHODOLOGY/PRINCIPAL FINDINGS: DIO mice were treated with the Genz-112638 for 12 to 16 weeks by daily oral gavage. Genz-112638 lowered HbA1c levels and increased glucose tolerance. Whole body adiposity was not affected in normal mice, but decreased in drug-treated obese mice. Drug treatment also significantly lowered liver triglyceride levels and reduced the development of hepatic steatosis. We performed hyperinsulinemic-euglycemic clamps on the DIO mice treated with Genz-112638 and showed that insulin-mediated suppression of hepatic glucose production increased significantly compared to the placebo treated mice, indicating a marked improvement in hepatic insulin sensitivity. CONCLUSIONS/SIGNIFICANCE: These results indicate that GSL inhibition in obese mice primarily results in an increase in insulin action in the liver, and suggests that GSLs may have an important role in hepatic insulin resistance in conditions of obesity.
Subject(s)
Diet/adverse effects , Glucosyltransferases/antagonists & inhibitors , Insulin/metabolism , Liver/drug effects , Liver/metabolism , Obesity/metabolism , Pyrrolidines/pharmacology , Adipose Tissue/drug effects , Adipose Tissue/metabolism , Animals , Body Weight/drug effects , Eating/drug effects , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Fatty Liver/drug therapy , Fatty Liver/metabolism , Glucose/metabolism , Glucose Clamp Technique , Glycated Hemoglobin/metabolism , Hyperinsulinism/metabolism , Male , Mice , Obesity/enzymology , Obesity/etiology , Obesity/physiopathology , Pyrrolidines/therapeutic use , Sphingolipids/metabolismABSTRACT
Obesity is a significant healthcare problem worldwide and increases the risk of developing debilitating diseases including type 2 diabetes, cardiovascular disease, and cancer. Although the health benefits of weight reduction are well-recognized, weight loss by diet and exercise fail in most patients, and the current marketed drugs have had limited success. It is clear that there is a significant unmet medical need for safe and effective weight-reducing agents. In this review, the current status of potential weight loss approaches that are in development by the pharmaceutical and biotechnology industry are discussed. This should lead to novel treatments that can be used long-term to effectively treat this serious metabolic disorder.
