Clinical and experimental studies have shown that sodium glucose co-transporter 2 inhibitors (SGLT2i) contribute to the prevention of diabetic kidney disease progression. In order to clarify its pharmacological effects on the molecular mechanisms underlying the development of diabetic kidney disease, we administered different doses of the SGLT2i, ipragliflozin, to type 2 diabetic mice. A high-dose ipragliflozin treatment for 8 weeks lowered blood glucose levels and reduced urinary albumin excretion. High- and low-dose ipragliflozin both inhibited renal and glomerular hypertrophy, and reduced NADPH oxidase 4 expression and subsequent oxidative stress. Analysis of glomerular phenotypes using glomeruli isolation demonstrated that ipragliflozin preserved podocyte integrity and reduced oxidative stress. Regarding renal tissue hypoxia, a short-term ipragliflozin treatment improved oxygen tension in the kidney cortex, in which SGLT2 is predominantly expressed. We then administered ipragliflozin to type 1 diabetic mice and found that high- and low-dose ipragliflozin both reduced urinary albumin excretion. In conclusion, we confirmed dose-dependent differences in the effects of ipragliflozin on early diabetic nephropathy in vivo. Even low-dose ipragliflozin reduced renal cortical hypoxia and abnormal hemodynamics in early diabetic nephropathy. In addition to these effects, high-dose ipragliflozin exerted renoprotective effects by reducing oxidative stress in tubular epithelia and glomerular podocytes.

SummaryBackground and objectives S100A12 is an endogenous receptor ligand for advanced glycation end products. Cardiovascular disease remains a major cause of morbidity and mortality in patients with chronic kidney disease. In this study, we report cross-sectional data on 550 hemodialysis patients and assess the relationship between plasma S100A12 level and cardiovascular disease.Design, setting, participants, & measurements A cross-sectional study of 550 maintenance hemodialysis patients was conducted. We investigated the past history of cardiovascular disease and quantified the plasma level of S100A12 protein in all participants.Results Plasma S100A12 level was higher in hemodialysis patients with cardiovascular disease (n ϭ 197; 33.8 Ϯ 28.1 ng/ml) than in those without it (n ϭ 353; 20.2 Ϯ 16.1 ng/ml; P Ͻ 0.001). In multivariate logistic regression analysis, the plasma S100A12 level (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.13 to 1.44; P Ͻ 0.001) was identified as an independent factor associated with the prevalence of cardiovascular disease. The other factors associated with the prevalence of cardiovascular diseases were the presence of diabetes mellitus (OR, 2.81; 95% CI, 1.79 to 4.41; P Ͻ 0.001) and high-sensitivity CRP level (OR, 1.02; 95% CI, 1.00 to 1.05; P ϭ 0.046). Furthermore, the plasma S100A12 level (OR, 1.30; 95% CI, 1.09 to 1.54; P ϭ 0.004) was significantly associated with cardiovascular disease even in hemodialysis patients without diabetes mellitus (n ϭ 348). ConclusionsThese results suggest that the plasma S100A12 protein level is strongly associated with the prevalence of cardiovascular disease in hemodialysis patients.

BackgroundThe pathophysiological mechanisms of cisplatin nephrotoxicity include the reduction of renal blood flow, as well as tubular epithelial cell toxicity. The objective of this study was to investigate the influence of lower blood pressure and decreased food intake on the incidence of cisplatin nephrotoxicity.MethodsWe conducted a retrospective cohort study at a university hospital between 2011 and 2012. We identified hospitalized adult patients with head and neck cancer, esophageal cancer, or gastric cancer, who received intravenous cisplatin administration. The primary outcome was the incidence of cisplatin nephrotoxicity defined as the increase in serum creatinine after cisplatin administration more than 1.5 times from baseline.ResultsThe study participants included 182 patients, in whom we observed a total of 442 cycles of cisplatin chemotherapy. The incidence of cisplatin nephrotoxicity was observed in 41 of 182 cycles with initial administration. Multivariate logistic regression analysis showed that systolic blood pressure was independently associated with cisplatin nephrotoxicity (adjusted odds ratio 0.75, 95% confidence interval 0.57 to 0.95 for each 10 mmHg). The use of renin-angiotensin system (RAS) inhibitors was also associated with cisplatin nephrotoxicity (3.39, 1.30 to 8.93). Among quartiles of systolic blood pressure in all cycles of chemotherapy, the incidence of nephrotoxicity in the lower blood pressure group was significantly higher than that in the higher blood pressure group for patients taking non-solid food (P = 0.037), while there was no significant difference for patients taking solid food (P = 0.67).ConclusionsLower blood pressure and the use of RAS inhibitors were associated with the incidence of cisplatin nephrotoxicity, and lower blood pressure had a greater influence on nephrotoxicity in patients who could not take solid food. Discontinuation of antihypertensive medication including RAS inhibitors before cisplatin chemotherapy should be considered, which may be beneficial for patients with lower blood pressure.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-017-3135-6) contains supplementary material, which is available to authorized users.

Unilateral ureteral obstruction is a well-established experimental model of progressive renal fibrosis. We tested whether mechanical stretch and subsequent renal tubular distension might lead to renal fibrosis by first studying renal tubular epithelial cells in culture. We found that mechanical stretch induced reactive oxygen species that in turn activated the cytoplasmic proline-rich tyrosine kinase-2 (Pyk2). This kinase is abundantly expressed in tubular epithelial cells where it is activated by several stimuli. Using mice with deletion of Pyk2 we found that the expression of transforming growth factor-β1 induced by mechanical stretch in renal tubular epithelial cells was significantly reduced. The expression of connective tissue growth factor was also reduced in the Pyk2(-/-) mice. We also found that expression of connective tissue growth factor was independent of transforming growth factor-β1, but dependent on the Rho-associated coiled-coil forming protein kinase pathway. Thus, Pyk2 may be an important initiating factor in renal fibrosis and might be a new therapeutic target for ameliorating renal fibrosis.

OBJECTIVE: This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD). METHODS: Sixty patients with CKD and well-controlled hypertension being treated with a reninangiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group. RESULTS: Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate. CONCLUSIONS: Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.