Objective To assess the influence of protein intake on nutritional status and mineral metabolism in patients with maintenance hemodialysis (MHD). Methods A cross-sectional study and a prospective cohort study were conducted. According to dietary protein intake (DPI), patients were divided into two groups: DPI≥1.2 g?kg-1?d-1 group (HP group) and DPI＜1.2 g?kg-1?d-1 group (NP group). One hundred and twenty-six MHD patients were enrolled in the cross-sectional study and their datum of dietary intake, as well as laboratory examinations were recorded. In the prospective cohort study lasted 2 years, 32 MHD patients were enrolled, with their dietary and laboratory examinations being collected every 3 months, and somatometric measurements being recorded at the beginning and the end of the study. Results In the cross-sectional study, the average DPI of HP group was (1.36±0.14) g?kg-1?d-1 and the average DPI of NP group was (1.04±0.09) g?kg-1?d-1. Compared with patients in NP group, patients in HP group had higher DPI, daily energy intake (DEI), normalized protein equivalent of nitrogen appearance rate (nPNA) and serum phosphate, and lower carbon dioxide combining power (CO2CP) (all P＜0.05) . There was no difference between two groups in hemoglobin, total protein, albumin, total cholestoral, blood calcium and intact parathyroid hormone (iPTH). In the prospective cohort study, the average DPI of HP group was (1.35±0.13) g?kg-1?d-1 and the average DPI of NP group was (1.05±0.11) g?kg-1?d-1. During the follow-up period, there were no significant differences in times comparison (all Ptime＞0.05). There was higher DPI, nPNA and serum phosphate, and lower CO2CP in HP group, than those in NP group (all Pgroup＜0.05). In terms of hemoglobin, total protein, albumin, total cholestoral and somatometric measurements, there was no difference between two groups (all Pgroup＞0.05). Conclusions DPI around 1.05 g?kg-1?d-1 can satisfy the nutritional requirement in MHD patients with good nutrional status, and ameliorate hyperphosphatemia and acidosis.

Objective To investigate the incidence and to evaluate the risk factors of acute kidney injury (AKI) following cardiac surgery with cardiopulmonary bypass (CPB) at general hospitals. Methods A retrospective cohort database study was conducted, involving 233 patients who were scheduled to heart valve surgery or coronary artery bypass grafting (CABG) with CPB technique. Logistic regression was used to screen out the risk factors of AKI after the surgery. Results The study population, with an average age of 57±12 years (age 21 to 83) were investigated, there were 54(23.2%) diabetes patients, 105 (45.1%) hypertension patients, 21 (9%) chronic kidney disease (CKD) patients, and 51 (21.9%) anemia patients. Overall incidence of AKI was 32.2%. The Analysis Result indicates that preoperative CKD, anemia, hypoalbuminemia, left ventricular ejection fraction, intraoperative aortic block time, minimum mean arterial pressure, perioperative infection, and application of vancomycin are risk factors associated with postoperative AKI. Multiariable Logistic regression suggests that basic CKD (OR=9.498, P=0.001), anemia (OR=3.150, P=0.021), the LVEF before surgery (OR=1.733, P=0.045), intraoperative aortic block time (OR=2.227, P=0.026), and white blood cell (OR=3.357, P=0.032) were the independent risk factors of AKI. Conclusions AKI is a common complication following cardiac surgery with CPB. The patients with preoperative renal insufficiency, anemia, long intraoperative aortic block time and higher perioperative white blood cell count are subjected to a higher incidence of AKI. Alleviating patients’ anemia and reducing artery block of extracorporeal circulation time therefore might be potential means to mitigate the risks of AKI after cardiac surgery.

Objective To explore the effects of renal artery calcification on the progression of diabetic nephropathy (DN), the activation and its role of bone morphogenetic protein 2(BMP2) signal pathway in renal artery of rats. Methods Sixty male SD rats were randomly divided into control group(CON group), DN group and DN with vascular calcification group (DN+VDN group). Rats of group DN and DN+VDN were fed with high sugar and fat diet and injected with streptozocin (STZ) into abdominal cavity to induce diabetes. After diabetic models were successfully made, rats of group DN+VDN were treated by vitamin D3 plus nicotine. The rats were sacrificed at 8th, 12th and 16th week respectively and the levels of renal function, blood glucose and 24 h urinary protein (24-h Upro) were measured. The pathologic changes to the renal artery were observed by von-Kossa staining and the calcium content was detected by calcium assay kit. The pathologic changes to the kidney were observed by HE. Immunohistochemistry was applied to detect the protein expression of BMP2/Smad1/Runx2/Osterix signal pathway in the renal artery and real-time PCR were applied to detect the mRNA expression levels of BMP2 and Runx2. Results The calcium content and the deposition of black granules in DN group were significantly higher than those in group CON and lower than DN+VDN group at each time point (P＜0.05). The renal function indices in group DN and group DN+VDN were gradually increased in 8th,12th and 16th weeks, and were higher than those in group CON (P＜0.05). Compared with that in DN group, although the level of BUN, Scr, Cys C and 24-h Upro in DN+VDN group rats were higher at different time point, the level of Cys C at each time point and the level of 24-h Upro in the 16th week showed significant differences (P＜0.05). The pathological damages of the kidney in group DN and DN+VDN showed a continual worsening trend and the pathological changes of the kidney in group DN+VDN were more serious than those in group DN. Furthermore, the levels of BMP2/Smad1/Runx2/Osterix signal protein and BMP2, Runx2 mRNA in DN rats were higher than those in CON group, lower than DN+VDN group at each time point (P＜0.05). Correlation analysis demonstrated that calcium content was positively correlated with serum BUN, Scr, Cys C, 24-h Upro and the expression of BMP2, Runx2 mRNA (r=0.835, 0.705, 0.829, 0.897, 0.641, 0.683, P＜0.01, respectively). Conclusion Renal artery calcification may participate in and promote the progression of DN, and the BMP2 signal pathway may be an important regulating factor in DN with renal artery calcification.

To investigate the utility of diffusion weighted imaging (DWI) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in the assessment of renal hypoxia in an experimental model of mice with lupus nephritis（LN). Methods MRL/lpr mice (n=13) were studied and C57BL/6 mice (n=10) served as controls. Urinary albumin to creatinine ratio (ACR), serum creatinine (Scr), anti-ds-DNA antibody, and complement C3 levels were measured. The mice underwent coronal echo-planar DWI and BOLD MRI of the kidneys when they were 14-16 weeks old. Hypoxyprobe was administered intraperitoneally to the mice 1 hour before they were sacrificed. The distribution of HypoxyprobeTM-1, hypoxia-inducible factor 1α (HIF-1α) and heme oxygenase-1 (HO-1) in renal tissues was detected by immunohistochemical analysis and Western blotting. Results Urinary ACR, Scr and anti-ds-DNA antibody levels in MRL/lpr mice were significantly higher than that in C57BL/6 mice. It was found that HypoxyprobeTM-1, HIF-1α and HO-1 distributed widely in the renal tissue of MRL/lpr mice, and closely associated with the renal tubulointerstitial lesion. The mean apparent diffusion coefficient (ADC) value of kidneys in MRL/lpr mice was (1.52±0.27) ×10-3 mm2/s, and the mean R2* values of the renal cortex and medulla were (30.95±4.59)/s and (23.43±3.06)/s respectively, all significantly lower than that in C57BL/6 mice (P=0.037, P=0.030 and P=0.043, respectively). The ADC of medulla was negatively correlated with urinary albumin to creatinine ratio (r=-0.364, P=0.032; r=-0.329, P=0.050), the ADC of cortex was negatively correlated with the level of serum creatinine (r=-0.814, P=0.014; r=-0.755, P=0.031) when b value was 500 s/mm2 and 800 s/mm2, and the mean R2* value was negatively correlated with the degree of tubulointerstitial lesions and the expression of hypoxia parameters (all P＜0.05). Conclusions Renal hypoxia may play an important role in renal tubulointerstitial lesion. Functional MRI may be used to monitor renal function changes, pathological injuries and renal hypoxia in LN.

Objective To investigate the role of RANK in injured podocyte and its effects on proteinuria. Methods PCR analysis was carried out to identify the genotypes of podocyte-specific RANK knockout mice. Six (6-8 weeks old) female RANK-/- mice were chosen as KO group. Six (6-8 weeks old) littermates and six (6-8 weeks old) C57/B6j mice were chosen as WT group and C57 group respectively. Each group was injected with LPS to create podocyte-injured proteinuria model. 24h urine was collected before and after injection. Urinary albumin, urine creatinine and UACR were detected by automatic biochemical analyzer. The mice were sacrificed after 48 h. Cortical kidney tissue samples were stained by PAS and collected for transmission electron microscopy to detect the foot process effacement. The number of podocytes was examined at different time points by immunohistochemistry .The expression of intergrin-β1, integrin-β3 and uPAR was detected by immunofluorescence and westernblot. Results (1) Comparing KO group, WT group and C57 group, it was found that there was no difference in weight, morphology, function of kidney and ACR. (2) After LPS injection, proteinuria and ACR were increased in three groups, but less significantly in KO group (23.70±9.90), compared to those in WT group (107.56±22.32) and C57 group (132.13±14.26) (P＜0.001). (3) In three groups, the number of podocytes was decreased after LPS injection and the decrease in the KO group was the slightest. (4) Compared to WT and C57 group, podocyte foot process effacement was less obvious in KO group after LPS injection in transmission electron microscopy. (5) Immunofluorescence results showed that after LPS injection, integrin-β1 was decreased in three groups, but most significantly in KO group. Integrin-β3 was increased in three groups, but less obvious in KO group. (6) Westernblot results showed consistency with immunofluorescence. The expression of uPAR protein was increased in three groups, with the increase in KO group being the slightest. Conclusions Podocyte-specific knockout of RANK reduces LPS-induced proteinuria, suggesting that RANK might be involved in the development of proteinuria in podocyt injury. Its mechanism is probably related with integrin-β1, integrin-β3 and uPAR.

Objective To assess the effects of tacrolimus (FK506) on podocyte in type 2 diabetic model rats and to explore the potential mechanism. Methods The model rats were fed with high fat and high sugar food and combining with a low-dose of streptozotocin (STZ). They were then randomly divided into a diabetic mellitus group (DM group) and a FK506 group. A normal control group (NC group) was also set. The rats in FK506 group were given with 0.5 mg?kg-1?d-1 FK506 for 8 weeks. The biochemical parameters were measured. The changes of renal pathology and ultrastructure of podocyte were observed by the light and electron microscopy. The expression of nephrin and LC3-Ⅱ was determined by immunohistochemistry and Western blotting. Results (1) Compared with those in NC group, KW/BW, systolic blood pressure (SBP), fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), urinary albumin excretion rate (UAE) and creatinine clearance rate (Ccr) in DM group were significantly increased (all P＜0.05). And the KW/BW, UAE and Ccr were decreased in FK506 group compared to those in DM group (all P＜0.05), while other parameters had no significant difference (all P＞0.05). (2) Compared with those in NC group, the glomerular volume, mesangial cell proliferation and accumulation of mesangial matrix were increased, and the foot process became disorder and fusion in DM group, while these changes were significantly reduced in FK506 group. (3) Compared with that in NC group, the expression of nephrin and LC3-Ⅱ was decreased in DM group (all P＜0.05), and both of parameters were higher in FK506 group than those in DM group (all P＜0.05). Conclusion FK506 may enhance podocyte autophagy in type 2 diabetic model rats and attenuate podocyte injury.

Objective To explore the effects of glucagon-like peptide-1 (GLP-1) analogues liraglutide on renal tissues of diabetic rats and its mechanism. Methods Forty male SD rats were randomly divided into four groups: normal control rats (NC group), normal control rats with liraglutide treatment (NCL group), diabetic rats (DM group) and diabetic rats with liraglutide treatment. The body weight, glycosylated hemoglobin (HbA1c), albuminuria/creatinine (A/C), kidney index (KI, kidney mass/body mass) were detected after 8 weeks treatment. The gene expression of tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1), type IV collagen, and transforming growth factor-β1 (TGF-β1) were measured by real time PCR. The protein expression of COL-Ⅳ, NF-κB, GLP-1R and phosphorylation levels of ERK, JNK and p38MAPK were evaluated by Western blotting. Results Compared to NC group, the body weight in DM group was reduced, and HbA1c, KI, A/C levels were significantly increased (P＜0.05). The gene expression of TNF-α, IL-6, IL-1β, MCP-1, TGF-β1 and COL- IV was increased (P＜0.05). Moreover, the protein expression of NF-κB in the nucleus of the kidney tissues and the phosphorylation levels of ERK, JNK and p38MAPK were significantly increased in DM group, accompanied by the decline of GLP-1R protein level (P＜0.05). After 8 weeks of liraglutide treatment, the urinary protein excretion was reduced, and the gene expressions of TNF-α, IL-6, IL-1β, MCP-1, TGF-β1, COL-IV were inhibited. Importantly, the phosphorylation levels of ERK and JNK were significantly inhibited and the expression of NF-κB protein in the nucleus of the kidney tissue was reduced (P＜0.05). These changes may be associated with the increased expression of GLP-1R after liraglutide treatment. However, blood glucose and the body weight in DML group rats had no significant changes after liraglutide treatment. Conclusion Liraglutide has a protective effect on renal tissues through inhibiting ERK and JNK phosphorylation and related inflammation in diabetic rats.

Objective To investigate the influence of thymosin beta 4 (Tβ4) with two different dosages on the expression of transforming growth factor beta (TGF-β) and connective tissue growth factor (CTGF) in rats with renal tubular interstitial fibrosis, and to further estimate the changes of renal tubular interstitial lesions. Methods Rat models of renal tubular interstitial fibrosis were established by unilateral ureteral occlusion (UUO). The male SD rats were randomly divided into 4 groups and 15 rats in each group: sham group, model group, treatment group with 1 mg/L Tβ4 and treatment group with 5 mg/L Tβ4. Rats in sham group and model group were poured into the same amount of saline. The renal function and renal pathological changes were observed after the second week. The mRNA and protein expression of TGF-β and CTGF in renal tissues was tested by in-situ hybridization and Western blotting. Results Compared with that in sham group, the expression of TGF-β mRNA and its protein, CTGF mRNA and its protein was significantly higher in model group (all P＜0.01). Compared with rats of model group, Tβ4 treatment rats had lower mRNA and protein expression of TGF-β and CTGF (all P＜0.01), and the expression in treatment group with 5 mg/L Tβ4 was lower than that in treatment group with 1 mg/L Tβ4 (P＜0.05). And the expression of TGF-β mRNA was positively correlated with CTGF mRNA expression (r=0.697, P＜0.01). The 24 h total urinary protein and the area of renal tubular interstitial lesion in model group were significantly more than those in sham group, and also more than those in Tβ4 treatment group (all P＜0.05). Tβ4 treatment attenuated kidney damage, and the effects in treatment group with 5 mg/L Tβ4 were better than those in treatment group with 1 mg/L Tβ4. No difference in serum creatinine and blood urea nitrogen was observed among 4 groups (all P＞0.05). Conclusions Tβ4 treatment can inhibit the renal TGF-β and CTGF expression of rats with tubular interstitial fibrosis in a dose-dependent manner, and play a protective role in kidney.

Objective To observe the expression of Klotho and Na+/Pi cotransporter in high phosphorous-induced rats with 5/6 nephrectomy and its relationship with vascular calcification, as well as to investigate the effect of early intervention by sodium thiosulfate (STS) on the progression of vascular calcification. Methods Either 5/6 nephrectomy (n=21) or sham operation (n=14) was conducted on 35 Sprague Dawley rats, who were then fed with high phosphorus (HP) diet or normal phosphorus (NP) diet for 16 weeks respectively. The rats were divided into 5 groups as follows: (1) remnant kidney rats receiving HP diet (NHP, n=7), (2) remnant kidney rats receiving NP diet (NNP, n=7), (3) sham operation rats receiving NP diet (SNP, n=7), (4) sham operation rats receiving HP diet (SHP, n=7), (5) remnant kidney rats receiving HP diet with STS (THP, n=7). The treatment group was given STS intraperitoneally three times a week for 16 weeks. At the end of the 16th week, rats tail artery blood pressures were tested, serum creatinine (Scr), calcium (Ca2+), phosphorus (P3+), FGF23, iPTH and urine protein were examined. Throacic aorta and kidney were then removed. Vascular calcification was confirmed by Von kossa staining. Klotho and Pit-1 expression in aortas were determined by immunohistochemistry. Renal lesion was determined by PASM-Masson staining. Renal Klotho and NaPi-2a mRNA were determined by real time RT-PCR. Results After 16 weeks, Scr, P3+, FGF23, iPTH, uric protein and blood pressure were significantly higher in NHP than those in SNP rats (all P＜0.05). PASM-Masson staining revealed typical renal pathology of chronic renal failure in NHP group. With the treatment of STS, THP rats showed significant decrease in Scr, P3+, FGF23, iPTH, uric protein and blood pressure by comparison with NHP group (all P＜0.05). Significant vascular calcification was found in NHP group while NNP and SHP group occasionally had vascular calcification; THP group had marked alleviation of vascular calcification. The aorta and renal expression of Klotho decreased remarkably while expression of Pit-1 and NaPi-2a increased significantly in NHP compared with SNP group (all P＜0.05). Accordingly, the aorta and renal expression of Klotho increased and Pit-1 and NaPi-2a decreased significantly in THP compared with NHP group (P＜0.05). Conclusions The early intervention of sodium thiosulfate might regulate Klotho and Na+/Pi cotransporter expression in both aorth and kidney, decreasing serum phosphate, delaying progression of vascular calcification and improving renal function.

Objective To investigate the role of tet methylcytosine dioxygenase 2 (TET2) in the regulation of transforming growth factor-β1 (TGF-β1) expression in human glomerular mesangial cells induced by high glucose. Methods Cultured human glomerular mesangial cells were divided into normal control group (5.5 mmol/L glucose) and high glucose group (30.0 mmol/L glucose) which was cultured for 12 h to 72 h. The gene expression of TET2 in mesangial cells were inhibited by small molecule chemical called SC1, and which were divided into high glucose group (30.0 mmol/L glucose+DMEM), DMSO group (30.0 mmol/L glucose+0.1%DMSO) and SC1 group (30.0 mmol/L glucose+3 μmol/L SC1). The mRNA and protein expression of TGF-β1, TET1 to 3 and α-smooth muscle actin (α-SMA) was detected by quantitative real-time PCR and Western blotting. Methylation of CpG islands in the regulation region of TGF-β1 was detected by bisulfite sequencing PCR (BSP). The activity of mesangial cell proliferation was assessed by colorimetry of thiazolyl blue (MTT). Results Compared with normal control group, the mRNA and protein expression of TET2 in mesangial cells induced by high glucose was increased significantly in a time-dependent manner (all P＜0.05), but the expression of TET1 and TET3 was not affected. Meanwhile methylation rate of 4 CG sites from 24 h to 72 h were decreased in the first exon of TGF-β1 (P＜0.01), but not in the promoter. Compared with high glucose group, when the expression of TET2 was inhibited by SC1, the methylation rate of TGF-β1 was recovered evidently (P＜0.05), the mRNA and protein expression of TGF-β1 and α-SMA was suppressed, and the proliferation of mesangial cells was decreased (all P＜0.05). Conclusions Demethylation of the CpG island mediated by TET2 may play an important role in the expression of TGF-β1 and mesangial cell phenotype transformation induced by high glucose.