Chuanming Hao

Sirt1 Activation Ameliorates Renal Fibrosis by Inhibiting the TGF-β/Smad3 Pathway

TGF‐β signaling plays an important role in the pathogenesis and progression of chronic kidney disease (CKD). Smad3, a transcription factor, is a critical fibrogenic mediator of TGF‐β. Sirt1 is a NAD+‐dependent deacetylase that has been reported to modify a number of transcription factors to exert certain beneficial health effects. This study examined the effect of Sirt1 on Smad3 and its role in CKD. Resveratrol attenuated the expression of extracelluar matrix proteins in both the remnant kidney of 5/6th nephrectomized rats and cultured mesangial cells (MMCs) exposed to TGF‐β1. The effect of resveratrol was substantially attenuated in cultured MMCs for which Sirt1 had been knocked down by an shRNA lentivirus. Overexpression of Sirt1 attenuated TGF‐β1‐induced extracelluar matrix expression in cultured cells. Co‐immunoprecipitation studies suggested that Sirt1 could bind with Smad3. Resveratrol treatment enhanced this binding and reduced acetylation levels of Smad3. Resveratrol inhibited the transcription activity of Smad3. Knockdown of Sirt1 increased acetylated Smad3 and substantially enhanced the transcriptional activity following TGF‐β1. Finally, Sirt1 deficiency aggravated renal function damage and markedly enhanced fibrosis in the remnant kidney of 5/6 nephrectomized mice. Taken together, these results identify Sirt1 as an important protective factor for renal fibrosis in a CKD rodent model, and the protective function of Sirt1 is attributable to its action on TGF‐β/Smad3 signaling. Therefore, we suggest that Sirt1 may be a potential therapeutic target for the treatment of CKD. J. Cell. Biochem. 115: 996–1005, 2014.

C/EBPβ and Its Binding Element Are Required for NFκB-induced COX2 Expression Following Hypertonic Stress

NFκB plays a critical role mediating COX2 expression in renal medullary interstitial cells (RMICs). The trans-activating ability of NFκB can be modified by another nuclear factor C/EBPβ that can physically bind to NFκB and regulate its activity. Because the COX2 promoter also contains a C/EBPβ site adjacent to the NFκB site, the present study examined whether these two transcription factors cooperate to induce COX2 expression following hypertonic stress. Hypertonicity markedly induced COX2 expression in cultured medullary interstitial cells by immunoblot analysis. The tonicity-induced COX2 expression was suppressed by mutant IκB (IκBm) that blocks NFκB activation, demonstrating that tonicity-induced COX2 expression depends on NFκB activation. However, mutation of the NFκB site in the COX2 promoter failed to abolish tonicity-induced COX2 reporter activity. IκB kinase-1 (IKK1) significantly induced COX2-luciferase activity by 2.3-fold (n = 10, p < 0.01); mutation of the NFκB site also failed to abolish IKK1-stimulated COX2 reporter activity (86 ± 3.1% of wild type, p > 0.05, n = 4). Interestingly, mutation of the C/EBPβ site of the COX2 gene significantly reduced both IKK1 and hypertonicity-induced COX2 reporter activity (p < 0.01). To further examine the potential role of C/EBPβ in tonicity-induced COX2 expression, a dominant negative C/EBPβ-p20 was transduced into RMICs. C/EBPβ-p20 markedly suppressed hypertonic (550 mOsm) induction of COX2 (immunoblot) to a similar extent as IκBm. No additional suppression was observed when both NFκB and C/EBPβ were simultaneously blocked by IκBm and C/EBPβ-p20. Interestingly, IKK-induced COX2 expression was not only blocked by IκBm, but also completely abolished by C/EBPβ-p20. Further studies demonstrated physical association of C/EBPβ to NFκB p65 by coimmunoprecipitation. Importantly, this interaction between C/EBPβ and NFκB was greatly enhanced following hypertonic stress. These studies indicate C/EBPβ is required for the transcriptional activation of COX2 by NFκB, suggesting a dominant role for the C/EBPβ pathway in regulating induction of RMIC COX2 by hypertonicity.

Association of Initial Twice-Weekly Hemodialysis Treatment with Preservation of Residual Kidney Function in ESRD Patients

Background: Residual kidney function (RKF) has consistently been a predictor of greater survival in maintenance hemodialysis (MHD) patients. The relationship between hemodialysis (HD) treatment frequency and RKF preservation has not been well examined. We hypothesized that initial twice-weekly HD helps in maintaining a longer RKF. Methods: In a dialysis center in Shanghai, 168 ESRD patients were screened and finally 85 patients were identified for this main cohort study. We first examined these 85 MHD patients; 30 of them were initiated with twice-weekly HD for 6 months or longer and 55 patients were started and maintained on thrice-weekly HD treatment. Then a subcohort study in 48 incident MHD patients was implemented to assess the independent risk factors responsible for RKF decline during the first year of HD therapy. Multivariate logistic regression analysis was then employed to examine the odds ratio of RKF loss. Results: The main cohort study showed that the clinical outcomes were almost the same between the two groups in 85 patients, but the percent of patients with RKF loss was significantly lower in the twice-weekly group compared with the thrice-weekly group, especially during the first year of HD initiation. In the 48 incident MHD patients, we found no significant differences between the two groups except for variations in the HD frequency, weekly Kt/V. The multivariate analysis showed that factors such as the male gender, HD frequency, URR and intradialytic hypotension episode were associated with RKF loss, and the odds ratio of RKF loss for each additional HD treatment per week was 7.2. Conclusion: Twice-weekly HD during the first year of dialysis therapy appears to be associated with better RKF preservation.

Resveratrol Attenuates Diabetic Nephropathy via Modulating Angiogenesis

Angiogenesis plays an important role in the pathogenesis of diabetic nephropathy (DN). In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with antiangiogenic activity in DN. In a type 1 diabetic rat model, resveratrol treatment blunted the increases of urine albumin excretion, kidney weight and creatinine clearance rate. The increases of glomerular diameter, mesangium accumulation, glomerular basement membrane thickness and renal fibrosis in diabetic rats were also reduced by resveratrol treatment. In the diabetic kidney, increased expression of vascular endothelial growth factor (VEGF), Flk-1 and angiopoietin 2, and reduced expression of Tie-2 were observed. These changes in angiogenic hormones and associated receptors were attenuated by resveratrol treatment. No changes in angiopoietin 1 expression were detected among each group of rats. Resveratrol also significantly downregulated high glucose-induced VEGF and Flk-1 expressions in cultured mouse glomerular podocytes and endothelial cells, respectively. These effects were attenuated by knocking-down silent information regulator 1 (Sirt1) expression. In contrast, upregulation of Sirt1 in cultured endothelial cells reduced Flk-1 expression. Increased permeability and cellular junction disruption of cultured endothelial cells caused by VEGF were also inhibited by resveratrol pretreatment. Taken together, the present study demonstrated that resveratrol may attenuate DN via modulating angiogenesis.

Risk of non-fatal cardiovascular diseases in early-onset versus late-onset type 2 diabetes in China: a cross-sectional study

BACKGROUND The age of onset of type 2 diabetes is decreasing. Because non-Chinese patients with early-onset type 2 diabetes (defined here as diagnosis at <40 years) have increased risk of vascular complications, we investigated effects of early-onset versus late-onset type 2 diabetes on risk of non-fatal cardiovascular diseases in China. METHODS We did a cross-sectional survey using data from the China National HbA1c Surveillance System (CNHSS), including 222,773 Chinese patients with type 2 diabetes in 630 hospitals from 106 cities in 30 provinces of China in 2012. We documented demographic information and clinical profiles. Non-fatal cardiovascular disease was defined as non-fatal coronary heart disease or non-fatal stroke. Prevalence of non-fatal cardiovascular diseases was standardised to the Chinese population in 2011. We did logistic regression analysis to obtain odds ratios (ORs) for the risk of cardiovascular disease in patients with early-onset versus late-onset type 2 diabetes. Because the CNHSS did not contain patients on diet or lifestyle treatment alone, and did not capture information on smoking or lipid or antihypertensive treatment, we validated our findings in another dataset from a cross-sectional, multicentre observational study (the 3B study) of outpatients with type 2 diabetes to confirm that exclusion of patients with diet treatment only and non-adjustment for lipid-lowering and antihypertensive drugs did not introduce major biases in the main analysis. FINDINGS Of 222,773 patients recruited from April 1, 2012, to June 30, 2012, 24,316 (11%) had non-fatal cardiovascular disease. Patients with early-onset diabetes had a higher age-adjusted prevalence of non-fatal cardiovascular disease than did patients with late-onset diabetes (11·1% vs 4·9%; p<0·0001). After adjustment for age and sex, patients with early-onset type 2 diabetes had higher risk of non-fatal cardiovascular disease than did those with late-onset type 2 diabetes (OR 1·91, 95% CI 1·81-2·02). Adjustment for duration of diabetes greatly attenuated the effect size for risk of non-fatal cardiovascular disease (1·13, 1·06-1·20). Results of the validation study showed that exclusion of patients with diet only and non-adjustment for lipid-lowering and antihypertensive drugs resulted in marginal changes in ORs for risk of non-fatal cardiovascular disease in patients with early-onset versus late-onset type 2 diabetes. Early-onset type 2 diabetes remained associated with increased risk of cardiovascular disease, attributable to longer duration of diabetes. INTERPRETATION Chinese patients with early-onset type 2 diabetes are at increased risk of non-fatal cardiovascular disease, mostly attributable to longer duration of diabetes. FUNDING Novo Nordisk China (for the China National HbA1c Surveillance System [CNHSS]) and Merck Sharp & Dohme China (for the 3B study).

The ratio of CRP to prealbumin levels predict mortality in patients with hospital-acquired acute kidney injury

BackgroundAnimal and human studies suggest that inflammation and malnutrition are common in acute kidney injury (AKI) patients. However, only a few studies reported CRP, a marker of inflammation, albumin, prealbumin and cholesterol, markers of nutritional status were associated with the prognosis of AKI patients. No study examined whether the combination of inflammatory and nutritional markers could predict the mortality of AKI patients.Methods155 patients with hospital-acquired AKI were recruited to this prospective cohort study according to RIFLE (Risk, Injury, Failure, Lost or End Stage Kidney) criteria. C-reactive protein (CRP), and the nutritional markers (albumin, prealbumin and cholesterol) measured at nephrology consultation were analyzed in relation to all cause mortality of these patients. In addition, CRP and prealbumin were also measured in healthy controls (n = 45), maintenance hemodialysis (n = 70) and peritoneal dialysis patients (n = 50) and then compared with AKI patients.ResultsCompared with healthy controls and end-stage renal disease patients on maintenance hemodialysis or peritoneal dialysis, patients with AKI had significantly higher levels of CRP/prealbumin (p < 0.001). Higher level of serum CRP and lower levels of albumin, prealbumin and cholesterol were found to be significant in the patients with AKI who died within 28 days than those who survived >28 days. Similarly, the combined factors including the ratio of CRP to albumin (CRP/albumin), CRP/prealbumin and CRP/cholesterol were also significantly higher in the former group (p < 0.001 for all). Multivariate analysis (Cox regression) revealed that CRP/prealbumin was independently associated with mortality after adjustment for age, gender, sepsis and sequential organ failure assessment (SOFA, p = 0.027) while the others (CRP, albumin, prealbumin, cholesterol, CRP/albumin and CRP/cholesterol) became non-significantly associated. The hazard ratio was 1.00 (reference), 1.85, 2.25 and 3.89 for CRP/prealbumin increasing according to quartiles (p = 0.01 for the trend).ConclusionsInflammation and malnutrition were common in patients with AKI. Higher level of the ratio of CRP to prealbumin was associated with mortality of AKI patients independent of the severity of illness and it may be a valuable addition to SOFA score to independent of the severity of illness and it may be a valuable addition to SOFA score to predict the prognosis of AKI patients.

Impact of Individual and Environmental Socioeconomic Status on Peritoneal Dialysis Outcomes: A Retrospective Multicenter Cohort Study

Objectives We aimed to explore the impacts of individual and environmental socioeconomic status (SES) on the outcome of peritoneal dialysis (PD) in regions with significant SES disparity, through a retrospective multicenter cohort in China. Methods Overall, 2,171 incident patients from seven PD centers were included. Individual SES was evaluated from yearly household income per person and education level. Environmental SES was represented by regional gross domestic product (GDP) per capita and medical resources. Undeveloped regions were defined as those with regional GDP lower than the median. All-cause and cardiovascular death and initial peritonitis were recorded as outcome events. Results Poorer PD patients or those who lived in undeveloped areas were younger and less-educated and bore a heavier burden of medical expenses. They had lower hemoglobin and serum albumin at baseline. Low income independently predicted the highest risks for all-cause or cardiovascular death and initial peritonitis compared with medium and high income. The interaction effect between individual education and regional GDP was determined. In undeveloped regions, patients with an elementary school education or lower were at significantly higher risk for all-cause death but not cardiovascular death or initial peritonitis compared with those who attended high school or had a higher diploma. Regional GDP was not associated with any outcome events. Conclusion Low personal income independently influenced all-cause and cardiovascular death, and initial peritonitis in PD patients. Education level predicted all-cause death only for patients in undeveloped regions. For PD patients in these high risk situations, integrated care before dialysis and well-constructed PD training programs might be helpful.

Renal phospholipase A2 receptor in hepatitis B virus-associated membranous nephropathy.

Objective: This study examined the expression of renal phospholipase A₂ receptor (PLA₂R) in idiopathic and secondary membranous nephropathy (MN). Methods: Patients with biopsy-proven MN and non-MN were enrolled. Renal PLA₂R was examined using an anti-PLA₂R antibody (anti-PLA₂R-Ab), and circulating PLA₂R-Ab was detected by indirect immunofluorescence. Results: Renal PLA₂R was detected along the capillary loop in 84% patients with idiopathic MN but not in those with any other primary glomerulonephritis. Only 1 of 38 patients with class V lupus nephritis showed renal PLA₂R positive. In hepatitis B virus-associated MN (HBV-MN), 64% showed renal PLA₂R positive, and PLA₂R overlapped with HBsAg along the capillary loop. In addition, renal PLA₂R positivity was closely associated with serum PLA₂R-Ab. Renal PLA₂R positive was present in all the patients with serum PLA₂R-Ab positive and in 53% of patients with serum PLA₂R-Ab negative. However, in patients with renal PLA₂R negative, serum PLA₂R-Ab was all negative. Conclusion: Renal biopsy PLA₂R positivity was common in idiopathic MN and HBV-MN but rare in lupus-associated MN, and it was closely associated with serum PLA₂R-Ab production. Further studies examining the association between PLA₂R and HBV-MN may shed light on the mechanism of idiopathic MN or HBV-MN.

2D-Speckle Tracking Echocardiography Contributes to Early Identification of Impaired Left Ventricular Myocardial Function in Patients with Chronic Kidney Disease

Background/Aims: Our aim was to investigate left ventricular (LV) physiology and short-axis and long-axis regional LV myocardial function throughout the cardiac cycle with 2D-speckle tracking echocardiography (2D-STE) in patients with chronic kidney disease. Methods: The study population consisted of 40 maintenance hemodialysis patients (hemodialysis group), 20 uremic patients hospitalized for creation of primary arteriovenous fistula (nondialysis group), and a control group of 20 healthy volunteers. LV regional longitudinal, circumferential and radial peak systolic velocity (Vs); early diastolic velocity (Ve); and peak systolic strain (Ε) were measured with 2D-STE. Results: Increased LV wall thickness and a decreased E/A ratio were found in the nondialysis and hemodialysis groups as compared to the control group, but there was no difference between the 2 study groups. Longitudinal Vs and Ve of the LV basal segment and middle segment in hemodialysis group and nondialysis group were all slower than those in the control group, and Vs in the nondialysis group was slower than that of the hemodialysis group. Circumferential and radial Vs and Ve were not different among the 3 groups, except that the radial Vs of LV basal segment was markedly decreased in the nondialysis group. Longitudinal peak systolic strain in the hemodialysis and nondialysis groups were both decreased as compared to the control group. Circumferential and radial peak systolic strain was decreased only in the nondialysis group. Conclusions: 2D-STE may be used to identify early abnormalities in patients with chronic kidney disease who have preserved LV ejection fraction. LV regional function appeared to be better in the hemodialysis group than that in the nondialysis group.

Meta-analysis comparing sevelamer and calcium-based phosphate binders on cardiovascular calcification in hemodialysis patients.

Background: Accelerated cardiovascular calcification often occurs in patients with cardiovascular disease who are on hemodialysis. We performed a meta-analysis to compare the effects of sevelamer hydrochloride and calcium-based phosphate binders on coronary artery calcification, C-reactive protein, alkaline phosphatase and intact parathyroid hormone in patients undergoing hemodialysis. Methods: We used the key words ‘sevelamer’ and ‘Renagel’ to retrieve studies from Medline, the Cochrane Library and conference proceedings. The trials searched were evaluated for eligibility and quality, and then the data were abstracted and analyzed. Results: We ultimately included 14 studies that enrolled a total of 3,271 patients. There was no difference in coronary artery calcium progression between the calcium and the sevelamer groups. Use of sevelamer, rather than calcium-based phosphate binders, was associated with significantly lower C-reactive protein levels (weighted mean difference (WMD) –1.42; 95% confidence interval (CI) –2.09 to –0.74), higher alkaline phosphatase levels (WMD 22.66; 95% CI 13.81–31.5) and higher intact parathyroid hormone levels (WMD 55.85; 95% CI 14.47–97.24). Conclusions: Treatment with sevelamer did not affect cardiovascular calcification, but there was a trend for lower C-reactive protein levels, higher alkaline phosphatase levels and intact parathyroid hormone levels among sevelamer-treated patients.