n-(1-methylethyl)-1-1-2-trimethylpropylamine and Kidney-Diseases

Cumulative evidence suggests that renal vascular endothelial injury play an important role in initiating and extending tubular epithelial injury and contribute to the development of ischemic acute renal failure. Our previous studies have demonstrated that iptakalim's endothelium protection is related to activation of SUR2B/Kir6.1 subtype of ATP sensitive potassium channel (K(ATP)) in the endothelium. It has been reported that SUR2B/Kir6.1 channels are widely distributed in the tubular epithelium, glomerular mesangium, and the endothelium and the smooth muscle of blood vessels. Herein, we hypothesized that activating renal K(ATP) channels with iptakalim might have directly neroprotective effects. In this study, glomerular endothelial, mesangial and tubular epithelial cells which are the main cell types to form nephron were exposed to oleic acid (OA) at various concentrations for 24 h. 0.25 microl/ml OA could cause cellular damage of glomerular endothelium and mesangium, while 1.25 microl/ml OA could lead to the injury of three types of renal cells. It was observed that pretreatment with iptakalim at concentrations of 0.1, 1, 10 or 100 micromol/L prevented cellular damage of glomerular endothelium and tubular epithelium, whereas iptakalim from 1 to 100 micromol/L prevented the injury of mesangial cells. Our data showed iptakalim significantly increased survived cell rates in a concentration-dependent manner, significantly antagonized by glibenclamide, a K(ATP) blocker. Iptakalim played a protective role in the main cell types of kidney, which was consistent with natakalim, a highly selective SUR2B/Kir6.1 channel opener. Iptakalim exerted protective effects through activating SUR2B/Kir6.1 channels, suggesting a new strategy for renal injury by its endothelial and renal cell protection.

Topics: Cells, Cultured; Epithelial Cells; Glyburide; Humans; KATP Channels; Kidney; Kidney Diseases; Oleic Acid; Propylamines; Protective Agents

It has been demonstrated that hyperuricemia induces reno-cardiovascular damage resulting in hypertension and renal injury because of vascular endothelial dysfunction. The pathogenesis of hyperuricemia, endothelial dysfunction, hypertension, and renal injury is progressive, and develops into a vicious cycle. It is reasonable to suggest that an antihypertensive drug with endothelial protection may block this vicious cycle. Iptakalim, a novel antihypertensive drug undergoing phase-three clinical trials, is a new ATP-sensitive potassium channel opener and can ameliorate endothelial dysfunction. We hypothesized that iptakalim could prevent hypertension and retard the pathogenesis of endothelial dysfunction and renal injury in hyperuricemic rats.. In rats with hyperuricemia induced by 2% oxonic acid and 0.1 mmol/l uric acid, iptakalim prevented increases in systolic blood pressure, reduced the impairment of endothelial vasodilator function, and attenuated renal dysfunction and pathological changes in glomerular and renal interstitial tissue at 0.5, 1.5, and 4.5 mg/kg orally daily for 4 weeks. Serum levels of nitric oxide and prostacyclin, and gene expression of endothelial nitric oxide synthase in the aortic and intrarenal tissue, were increased, whereas the serum levels of endothelin-1 and gene expression of endothelin-1 in aortic and intrarenal tissue were decreased. However, serum levels of angiotensin II and renin remained unchanged in the hyperuricemic rats treated with iptakalim. In cultured rat aortic endothelial cells, amelioration of endothelial dysfunction by iptakalim was suggested by inhibition of the overexpression of intercellular adhesive molecule-1, vascular cell adhesive molecule-1, and monocyte chemoattractant protein-1 mRNA induced by uric acid, and reversal of the inhibitory effects of uric acid on nitric oxide release in a concentration-dependent manner, which could be abolished by pretreatment with glibenclamide, an ATP-sensitive potassium channel blocker. Iptakalim ameliorated hyperuricemia in this rat model by decreasing renal damage through its antihypertensive and endothelial protective properties, and it had no direct effects on anabolism, catabolism and excretion of uric acid.. These findings suggest that the activation of ATP-sensitive potassium channels by iptakalim can protect endothelial function against hypertension and renal injury induced by hyperuricemia. Iptakalim is suitable for use in hypertensive individuals with hyperuricemia.

Topics: 6-Ketoprostaglandin F1 alpha; Angiotensin II; Angiotensins; Animals; Cells, Cultured; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; Hypertension; Hyperuricemia; KATP Channels; Kidney; Kidney Diseases; Male; Nitric Oxide; Oxonic Acid; Propylamines; Rats; Rats, Sprague-Dawley; Urate Oxidase; Uric Acid; Xanthine Oxidase

The effects of iptakalim, a new ATP-sensitive potassium channel opener, were studied in spontaneously hypertensive rats (SHR). Treatment of 12-week-old male SHR (six animals in each group) with iptakalim by gastric lavage at doses of 1, 3, or 9 mg/kg/day for 12 weeks resulted in a lowering of blood pressure. Iptakalim provided significant renoprotection to SHR rats as measured by decreased proteinuria and improved renal function. Histological evidence demonstrated that iptakalim could reverse renal vascular remodeling (of afferent arterioles, arcuate arteries, or interlobular arteries), and improve pathological changes of glomerular, renal interstitial, and glomerular filtration membranes. These effects were accompanied by the decreased circulation and intrarenal concentrations of endothelin 1 and transforming growth factor beta1 (TGF-beta1), and down-regulated overexpression of genes for ET-1, endothelin-converting enzyme 1, TGF-beta1, and the subunits of ATP-sensitive potassium channels (K(ATP)), Kir1.1 and Kir6.1, in the kidney during hypertension. Abnormal expression of matrix components [collagen IV, fibronectin, matrix metalloproteinase 9 (MMP-9) and MMP tissue inhibitor 1 (TIMP-1)] was also significantly reversed by iptakalim. Our results demonstrate that chronic treatment with iptakalim not only reduces blood pressure but also preserves renal structure and function in SHR. In addition to reducing blood pressure, the renoprotective of iptakalim may be involved in inhibiting the circulation and intrarenal concentrations of endothelin 1 and TGF-beta1, regulating the expression of K(ATP) genes and correcting MMP-9/TIMP-1 imbalance in renal tissue, which may result in reducing the accumulation of extracellular matrix molecules.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; ATP-Binding Cassette Transporters; Benzazepines; Endothelin-1; Extracellular Matrix; Hemodynamics; Hypertension; Immunohistochemistry; KATP Channels; Kidney; Kidney Diseases; Kidney Function Tests; Potassium Channels, Inwardly Rectifying; Propylamines; Rats; Rats, Inbred SHR; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta; Transforming Growth Factor beta1