Objective    To investigate the value of biomarker levels at the time of nephrologists consultation in predicting the prognosis of acute kidney injury (AKI) patients.    Methods    A total of 103 hospitalized patients with AKI were enrolled at the time of nephrologists consultation. Blood and urine samples were collected when patients were diagnosed as AKI. ELISA was used to detect the concentration of urinary biomarkers including neutrophil gelatinase?associated lipocalin (NGAL), IL?6 and IL?18. Colorimetric method was used to measure urinary N?acetyl?β?D?glucosaminidase (NAG). Turbidimetry and enzymic method were applied to examine the concentration of serum cystatin C (Cys C), baseline Scr (bScr), Scr at consultation (cScr) and the peak of Scr (pScr) respectively. Patients were followed?up to evaluate the prognosis at 28 days after consultation, including patient survival and kidney survival. The levels of biomarkers between different groups, including patient survival or death, kidney recovery or lose and renal replacement therapy (RRT) or not, were compared. Area under curve (AUC) of receiver operating characteristic (ROC) curve of these biomarkers were used to evaluate the sensitivity and specificity in predicting prognosis. AKI was defined as the Scr at the time of consultation increased more than 50% of baseline Scr within 48 hours.    Results    (1)Mean age of 103 hospitalized AKI patients was (54.28±19.05) years old and ratio of male to female was 1.86 to 1. (2)Patient mortality was 25.2% at 28 days after consultation. The bScr, cScr and pScr were similar between survival and death group, while the concentration of urinary NGAL in death group was significantly higher than that of survival group [147.00(31.59, 221.87) mg/L vs 22.43(6.48, 89.77) mg/L, P＝0.001]. The serum Cys C, urinary IL?6 and NAG were similar between survival and death group (P＞0.05). Logistic regression analysis showed urinary NGAL was an independent risk factor of patient survival (OR＝1.011, 95%CI 1.004?1.018, P＝0.001) with AUC of 0.723. (3)Kidney lose rate was 20.4% at 28 days after consultation. The bScr, cScr and pScr were similar between patients with kidney survival and lose. The levels of urinary NAG, IL?6, NGAL and IL?18 were significantly higher in patients with kidney lose than those of kidney survival. Logistic regression analysis showed urinary IL?6 was an independent risk factor of renal survival (OR＝1.056, 95%CI 1.009?1.105, P＝0.018) with AUC of 0.705. (4)The median time from consultation to RRT was 2.17 (0?3) days. The concentrations of cScr, pScr, serum Cys C, urinary IL?6 and NGAL were significantly higher in RRT patients than thosein non?RRT patients (P＜0.05). Logistic regression analysis showed urinary NGAL was an independent risk factor of RRT (OR＝1.012, 95%CI 1.005?1.019, P＜0.01) with AUC of 0.775.    Conclusions    Urinary NGAL can predict the prognosis of AKI patients, including patient prognosis and RRT. Urinary IL?6 may predict kidney prognosis in hospitalized patients with AKI. More study with large samples should be done for further estimation of the results.

Objective    To investigate the correlation between glycosylated hemoglobin (HbA1c) and carotid intima?media thickness (CIMT) in non?diabetic peritoneal dialysis patients.    Methods    Forty?two non?diabetic peritoneal dialysis adult patients were enrolled in this study [mean age was (48.2±12.3) years, 50% was male]. CIMT was determined by carotid ultrasound. Patients were divided into two groups according to CIMT: CIMT normal group (CIMT＜0.9 mm) and CIMT thickening group (CIMT≥0.9 mm). HbA1c, 2?hour postprandial blood glucose (2hPBG) and other factors of the patients were analyzed with Spearman rank correlation and multiple linear regression.    Results    CIMT was correlated with age, 2hPBG, LDL?C, TG, TC, HbA1c in non?diabetic peritoneal dialysis patients (r＝0.355, 0.373, 0.416, 0.345, 0.351, 0.456, all P＜0.05). Multiple linear regression showed that HbA1c was the most powerful influence factor of CIMT（β＝0.459）.    Conclusion    HbA1c level is positively correlated with CIMT and may be a predictor of carotid atherosclerosis in non?diabetic peritoneal dialysis patients.

Objective    To assess the prognostic values of  urinary kidney injury molecule 1 (KIM-1), interleukin 18 (IL-18) and cystatin C (Cys C) for gadolinium-based contrast-induced nephropathy (Gd-CIN) in the elderly patients.    Methods    A total of sixty elderly patients who underwent enhanced magnetic resonance imaging (MRI) using gadolinium-based contrast media (GBC) from December 2010 to December 2011 were enrolled. Serum and urine samples were collected before and after the procedure. The levels of urinary KIM-1, IL-18 and Cys C were measured by ELISA respectively. Serum and urine creatinine levels were measured by automatic biochemical analyzer.    Results    Among 60 patients, Gd-CIN was diagnosed in 8 (13.3%) patients. At 24 h after MRI in the Gd-CIN group, the levels of urinary KIM-1, IL-18 and Cys C were significantly increased compared with the baseline values. Compared with non-Gd-CIN group, the levels of urinary KIM-1, IL-18 and Cys C at 24 h  and urinary IL-18 at 48 h after GBC administration were significantly increased (P＜0.05). There were no significant differences in levels of urinary KIM-1, Cys C at 48 h after GBC administration between Gd-CIN and non-Gd-CIN group (P＞0.05). Logistic regression analysis showed that the levels of urinary KIM-1 and IL-18 at 24 h after GBC injection were independent predictive biomarkers of Gd-CIN (OR＝1.612, 1.009, all P＜0.05). The predictable time of acute kidney injury onset determined by urinary KIM-1, IL-18 and Cys C levels was 24 h earlier than that by serum creatinine.    Conclusion    Urinary KIM-1, IL-18 and Cys C may be early predictive biomarkers of elderly Gd-CIN, which shows a good performance in early diagnosis of Gd-CIN as compared with serum creatinine.

Objective    To validate cystatin (Cys C)-based equations for evaluation of residual renal function （RRF） in patients on continuous ambulatory peritoneal dialysis (CAPD).    Methods    Fifty patients on CAPD from our department were enrolled in the study. Eight patients with residual urine volume ≤100 ml/d and 42 patients with residual urine volume ＞100 ml/d were enrolled into anuria group and non-anuric group respectively. The clinical and laboratory status of each group were compared and equations (Hoek’s, Yang’s and abbreviated MDRD equations) were validated in the non-anuric group by comparing with the arithmetic average of residual renal creatinine clearance rate and residual renal urea clearance rate which was considered as the golden standard for RRF.    Results    (1) Anuric group had significantly higher serum Cys C than the non-anuric group [(7.73±1.13) mg/L vs (6.46±1.15) mg/L, t＝2.39, P＝0.02)]. (2) RRF estimated by each equation was correlated well with measured RRF (r＝0.56, 0.56 and 0.39, all P＜0.05). (3) Yang’s equation [0.10 ml•min^-1•(1.73 m²)^-1] was least biased, followed by Hoek’s equation [-0.73 ml•min^-1•(1.73 m²)-¹] and abbreviated MDRD equation [3.15 ml•min^-1•(1.73 m²)^-1]. (4) The precision of Yang’s equation was equivalent to that of Hoek’s equation and both of them were better than abbreviated MDRD equation [6.2 and 6.1 vs 8.4 ml•min^-1•(1.73 m²)^-1]. (5) 50% accuracy according to Yang’s equation and Hoek’s equation revealed an elevated results in comparison to that according to abbreviated MDRD equation (59.5% and 54.8% vs 23.8%, respectively, all P＜0.01).    Conclusions    Serum Cys C-based prediction equations are better than the abbreviated MDRD equation in bias, precision and 50% accuracy. For patients undergoing CAPD, the use of Cys C-based equation to estimate RRF may be a clinically acceptable alternative.

Objective    To explore whether high glucose (HG)-induced endothelial-to-mesenchymal transition (EndMT) could be transitioned into mesenchymal stem cells (MSCs) and further differentiated into chondrocytes.    Methods    Human aortic endothelial cells (HAECs) were divided into three groups: normal glucose (NG，5.5 mmol/L glucose) group, HG (30 mmol/L glucose) group, and mannitol (5.5 mmol/L glucose＋24.5 mmol/L mannitol) group, and were cultured for 48 h. Immunofluorescence staining was performed to detect the co-expression of CD31 (endothelial markers), and fibroblast-specific protein 1 (FSP1, fibroblast markers). The expression of CD31 and FSP1 mRNA and protein was detected by real-time PCR and Western blotting. When endothelial-derived MSCs were grown in MSC medium for one week, the expression of the MSCs markers CD44, CD10 and the chondrocyte marker SOX9 was detected by Western blotting and RT-PCR. Chondrocyte expression was detected by alcian blue staining. Calcium deposit was analyzed by alizarin red staining. Pathological changes were investigated using electron microscopy.    Results    The expression of FSP1 mRNA and protein was significantly increased, but the expression of CD31 mRNA and protein was decreased (P＜0.01), and the cells undergoing EndMT also significantly expressed CD10, CD44 and SOX9 in the HG group compared with those in normal glucose group (P＜0.01). The incubation of HAECs exposed to HG resulted in a fibroblast-like phenotype, wherein increased microfilamentation and a roughened endoplasmic reticulum structure were observed in the cytoplasm. Double staining of the HAECs indicated a co-localization of CD31 and FSP1. After one week culture for chondrocyte medium, the expression of MSCs marker STRO-1 was significantly increased by immunofluorescence staining. Additionally, alcian blue staining in the HG group was positive compared to the NG group. Consistent with the elevation of SOX9 expression, calcium deposit  also enhanced in the HG group.    Conclusion    HG can induce endothelial cells transdifferentiation into chondrocyte-like cells via the EndMT.
 

Objective    To observe the effects of endoplasmic reticulum stress (ERS) on the activation of monocytes induced by high glucose and explore the underlying mechanism.    Methods    The monocyte cell line THP-1 was stimulated with high glucose, and then treated with molecular chaperone betaine. The levels of glucose regulation protein 78 (GRP78) and p-JNK, which were associated with ERS were detected by real-time PCR and Western blotting. The proliferation of the cell line was detected by MTT method. Transwell and immunofluorescence were applied to observe the chemotaxis and phenotype of cells respectively.    Results    The levels of GRP78 and p-JNK of THP-1 cells stimulated by high glucose were significantly increased compared with the normal control group (all P＜0.05). The proliferation and chemotactic were also enhanced (all P＜0.05). The number of cells in M1 phenotype was increased remarkably (P＜0.05). All the indexes above could be rescued by betaine.    Conclusion    The activation of THP-1 cells can be induced by high glucose through ERS, while molecular chaperone betaine can reverse the activation.

Objective    To observe the effect of MG132 on the expression of extracellular regulated kinase 1/2 (ERK1/2) and connective tissue growth factor (CTGF) in rat peritoneal mesothelial cells (RPMCs) induced by high glucose.    Methods    RPMCs were isolated, cultured and passaged by trypsin, then identified. The second generation of cultured RPMCs were used in the experiment. RPMCs were divided into normal control group, high glucose (1.5%, 2.5%, 4.25%) for 24 hours, high glucose (2.5%) for 0, 12, 24, 48 hours，incubated with MG132 (0.5, 1, 2 μmol/L) for half an hour and then with high glucose (2.5%) for 24 hours. ERK1/2 protein was detected by Western blotting, and CTGF protein in supernatant was detected by ELISA.    Results    Compared with the control group, the expression of p-ERK1/2 was significantly increased in the groups stimulated by high glucose (P＜0.01), reached the peak at 24th hour (P＜0.01), and then the expression decreased at 48th hour, but still was higher than that in the normal control group (P＜0.01). CTGF protein expression of RPMCs induced by high glucose increased, in time- and dose-dependent manner (P＜0.05). MG132 could significantly decrease the expression of ERK1/2 and CTGF induced by high glucose (P＜0.05).    Conclusions    MG132 can decrease the expression of p-ERK1/2 and CTGF in RPMCs induced by high glucose. The ubiquitin proteasome pathway participates in the development of peritoneal fibrosis, and blocking the way may  contribute to the prevention of peritoneal fibrosis.

 Objectives    To investigate the impact of ischemic preconditioning (IPC) on dynamics of homing of endothelial progenitor cells (EPCs) after renal ischemia reperfusion injury (IR).    Methods    Sixty male Sprague-Dawley rats were randomly divided into three groups after right-side kidney nephrectomy: for sham-operated rats, lumbotomy without vascular clamping was performed; IR rats were clamped renal blood vessels for 40 minutes while IPC rats were pre-treated with 15 min ischemia and 10 min reperfusion. At 3, 12, 24 h, and 3 days after reperfusion, the pool of circulating, kidneys, lungs and spleens were harvested. The extent of renal injury was assessed by biochemical and histological examination. The dynamics of homing of EPCs was observed by flow cytometry.    Results     The rats in IPC group exhibited significant improvements in renal function and morphology. Compared with IR group and sham group, the number of EPCs in blood was increased in the IPC group at 12 h and 24 h after reperfusion (P＜0.05). The number of EPCs in kidney was increased at all times point in the IPC group and IR group as compared to the sham group (P＜0.05. In addition, EPCs number was increased in IPC group compared with the IR group at 12 h and 24 h [(11.36±0.66)% vs (6.37±0.69)%, (6.31±0.70)% vs (4.40±0.60)%, all P＜0.05]. Compared with IR group and sham group, the number of EPCs in the lung was increased in the IPC groups at 12 h after reperfusion [(2.95±0.66)% vs (1.78±0.59)%, (1.66±0.61)%, all P＜0.05]. The number of EPCs in spleen was increased in the IPC group at 72 h as compared with the IR group and sham group [(0.55±0.06)% vs (0.34±0.07)%, (0.31±0.06)%, all P＜0.05].    Conclusions    Endogenous EPCs may home to injured kidney after IPC. EPCs can also gather in the lungs and spleen.

Objective    To observe the muscle wasting in diabetic kidney disease (DKD) model of type 2 and non-obese diabetes mellitus in Goto-Kakizaki (GK) rats, and to evaluate the effect of low-protein diet supplemented with ɑ-keto acids on muscle wasting.    Methods    Forty-five male 24-week-age GK rats were randomly divided into three groups: normal protein diet group (22% casein diet, NPD), low protein diet group (6% casein diet, LPD) and LPD＋ɑ-keto group (5% casein＋1% ɑ-keto, Keto). Fifteen gender- and age-matched Wistar rats were served as the control group (CTL). The living condition of GK rats was observed and body weight was measured once a week. Urine albumin, serum glucose, lipids, albumin, creatinine and urea nitrogen were measured at the age of 24, 32, 40, 48 weeks. Soleus muscle at the age of 48-week was observed to calculate the muscle size with software. Expressions of atrogin-1, MuRF-1 and MyoD, myogenin were examined by Q-PCR and Western blotting.    Results    Compared with the CTL group, NPD, LPD, Keto groups had lower body weight [(317.90±13.81), (330.38±11.96), (390.44±12.25) g vs (429.43±16.85) g, all P＜0.05], higher urine albumin [(14.36±5.52), (8.12±4.61), (5.58±3.50) mg/24 h vs (0.61±0.16) mg/24 h, all P＜0.05], higher serum creatinine [(81.50±7.88), (66.32±8.36), (63.44±8.21) μmol/L vs (24.43±6.15) μmol/L, all P＜0.05] and urea nitrogen [(7.53±1.05), (5.63±1.40), (5.54±0.97) mmol/L vs (2.98±0.62) mmol/L, all P＜0.05]. The cross-sectional area of soleus muscle fibers was larger in CTL group. Compared with CTL group, the expression levels of atrogin-1 and MuRF-1 increased significantly (all P＜0.05), and of MyoD and myogenin decreased significantly in NPD, LPD, Keto groups (all P＜0.05). In Keto group after 40 weeks, muscle wasting was improved compared with NPD and LPD group [body weight (381.62±15.82) g vs (331.50±17.58), （326.60±13.43) g, all P＜0.05], cross-sectional area of soleus muscle increased, levels of urine albumin, serum creatinine and urea nitrogen decreased (all P＜0.05), the protein expressions of atrogin-1 and MuRF-1 decreased, and myogenin and MyoD were higher as compared to CTL group (all P＜0.05). There were no significant differences between NPD and LPD group.    Conclusions    In DKD condition, protein degradation in the skeletal muscle is accelerated, the genes which control muscle atrophy are activated, and proliferation and differentiation of the muscle satellite cells are impaired. Low-protein diet supplemented with ɑ-keto acids can improve muscle wasting induced by DKD.

Objective    To investigate the effect of angiotensinⅡ(AngⅡ) type 1 receptor blocker (ARB) on 12-lipoxygenase (12-LO) activity and P-cadherin expression in type 2 diabetic rat glomeruli.    Methods    Podocytes were stimulated by 10-7 mol/L AngⅡ for 24 hours. 12(S)-HETE (1 mg•kg-1•d-1) and AngⅡ (400 ng•kg-1•min-1) were infused to rats by osmotic mini-pump for 1 week and 2 weeks respectively. Rats fed with high fat diet received low dose streptozotocin (STZ) to make type 2 diabetes and divided into 2 groups: low dose STZ (DN group), low dose STZ＋ARB treatment (Losartan group). Rats fed with regular chow were used as control group. All the rats were sacrificed after 6 weeks. Urine, blood, kidney cortical tissue and isolated glomeruli by sieving method were collected at the end of study respectively. ELISA, RT-PCR and Western blotting for related target were performed respectively.    Results    AngⅡincreased 12(S)-HETE levels in podocytes and glomeruli (all P＜0.01). AngⅡ levels in the glomeruli were significantly increased by 12(S)-HETE stimulation (P＜0.01). Blood glucose, kidney/body weight and 24 hour urinary protein were increased in DN group compared with that in control group (all P＜0.01). However, urine protein, Kidney/body weight were decreased in Losartan group compared with DN group (all P＜0.05). Increment of 12(S)-HETE content and decrement of P-cadherin expression were observed in DN glomeruli compared with that in control group(all P＜0.01). These abnormalities were prevented by administration of the losartan (all P＜0.05).    Conclusions    AngⅡ can down-regulate glomerular P-cadherin expression via activation of 12-LO.ARB can ameliorate the progression of DN via up-regulation of glomerular P-cadherin through inhibition of 12-LO activation in type 2 DN rats.