Objective To investigate the expression of vascular endothelial growth factor (VEGF), angiopoietin and their receptors (VEGFR and Tie2) in aging mice kidney and the possible roles in aging mice. Methods Mice were divided as follows: 4-month old group (n=6), 9-month old group (n=6), 12-month old group (n=6) and 20-month old group (n=6). Paraffin sections of the mice kidneys were stained by PAS. The density of glomerular microvascular was determined by renal perfusion with fluorescent dyes. The level of VEGF, VEGFR2 (Flk-1), Ang-1, Ang-2, Tie2 mRNA expression and protein abundance in kidney was determined by real-time PCR, immunochemistry, immunofluorescence and Western blot. Results Compared with other three groups, in the 20-manth old group, the glomerulosclerosis index (GSI) increased remarkbly (2.48±0.79 vs 0.53±0.19, 0.69±0.18, 1.50±0.70, P<0.05); the fluorescence intensity in glomeruli decreased (P<0.05). lmmunohistochemistry demonstrated that the TGF-131 level in the aging kidneys showed an increase trend in the glomerular tubulointerstitium, and especially in the glomeruli. Real-time PCR results revealed that compared with 4-month old group mice, the mRNA expression of VEGF, Flk-1, Ang-1, Ang-2, Tie2 of the other three groups decreased, the gene levels of VEGF, Flk-1, and Ang-2 fell about 90%, 50% and 80% (all P>0.05), and the gene levels of Ang-1 and Tie2 fell about 75% and 40% in 20-month-old group (all P<0.05). Western blot domonstrated that the protein abundace of VEGF, Flk-1, Ang-1, Ang-2, Tie2 also declined with aging, the protein level of VEGF, Flk-1, Ang-1, Ang-2 and Tie2 dropped by about 35%, 50%, 15%, 13% and 21% respectively in 20-month-old group as compared to 4-month-old group (all P<0.05). Expression of above 5 factors and glomerular fluorescence intensity were negatively correlated with Scr (P<0.05). Conclusions The mRNA expression and protein abundance of VEGF, Flk-1, Ang-1, Ang-2, Tie2 in mice kidneys decreases with aging. Angiogenesis regulatory factors may play important roles in aging progression of the mice kidney.

Objective To investigate the expression of nestin, a type Ⅵ intermediate filament protein in the glomeruli with foot process effacement and the potential relationship between nestin expression in the kidney and the degree of proteinuria. Method Immunohistochemistry was used to determine the localization of nestin in the kidney samples obtained from needle biopsies of normal human and patients with minimal change disease (MCD). Puromycin aminonucleoside (PAN) nephrosis rat models were established by a single intraperitoneal injection of PAN. Both real time quatitative reverse PCR and Western blot methods were applied to evaluate the levels of nestin expression at day 1, 4, 10 and 20 after PAN injection. Results Immunohistochemistry showed that the expression of nestin in glomeruli of MCD patients was significantly reduced compared with normal samples (0.93±0.08 vs 1.65±0.12, P<0.05) . The mRNA and protein expressions of nestin in the rat kidney were transitorily increased by 1.23 folds and 1.48 folds of control group (NC) after 1 day of PAN injection (P<0.05), then decreased quickly in the following days. The mRNA levels of nestin in the kidney were 35.8% and 12.1% of NC after 4 days and 10 days of PAN injection, respectively, (P<0.01) as determined by real time PCR. After 20 days of PAN injury, nestin mRNA expression partly recovered to 65.8% of NC (P< 0.05 ). The protein levels of nestin detected by Western blot presented the similar trend, which were 77.0%, 58.0% and 83.4% of NC after 4 days, 10 days and 20 days of PAN injection, respectively (P<0.05). The degree of proteinuria in puromycin aminonucleoside nephrosis rats was negatively correlated with both mRNA and protein levels of nestin in the kidney(r=-0.667,P<0.05 and r=-0.621 ,P<0.05, respectively). Conclusions The expression of intermediate filament protein nestin is down-regnlated in the kidney characterized with foot process effacement and negatively correlated with the degree of proteinuria in puromycin aminonucleoside nephrosis rats. Nestin may play a potential role in modulating the structure and function of podocyte.

AIM: To study the effects of chronic metabolic acidosis on glomerulus, mesangial cells and the production of extracellular matrix. METHODS: Chronic metabolic acidosis was induced by addition of 0.28 mol/L NH_4Cl to drinking water for 3, 7, or 14 days in male Wistar rats (n=10). Light microscope combined with computer software (Motic Images Advanced 3.2) was used to determine the effect of chronic acid loading on renal morphologic changes. The expressions of proliferation cell nuclear antigen (PCNA) and p27 in glomeruli were detected by Western blotting or immunohistochemistry. Fibronectin (FN) mRNA was detected by real-time PCR. The proliferation of mesangial cells in vitro was determined by ~3H:-TdR incorporation. The concentration of FN in cultured supernatant was detected by ELISA. RESULTS: On day 1, 3, 7 and 14, the arterial pH and plasma HCO_3~-: in experimental rats were significantly decreased. There was a significantly increased in the kidney weight and the ratio of kidney to body weigh in experimental rats on day 3, 7 and 14. The glomerular area and cell numbers also increased significantly. Immunoblotting demonstrated decreased p27 expression and increased PCNA expression in isolated glomeruli, and the expression of PCNA increased in a time-dependent manner following the time of chronic metabolic acidosis. Immunohistochemistry showed increased positive PCNA expression mainly localized to mesangial cells. The expression of FN mRNA was significantly elevated in experimental rats on day 7 and 14. In vitro, acid loading induced mesangial cell proliferation and synthesis of FN. CONCLUSION: These results suggest that chronic metabolic acidosis induces mesangial cell proliferation, and its mechanism may be associated with the downregulation of cell cycle kinase inhibitor p27.

Objective To observe the changes of renin-angiotensin system (RAS) in cultured mesangial cells by serum from 3/4 nephrectomized rats feeding with low protein diet and α-keto acid. Methods Thirty male SD rats received 3/4 nephrectomy (Nx) were placed on 18%normal protein diet (NPD,n=10),6% low protein diet(LPD,n=10) or 5% low protein plus 1%α-keto acid diet (LK,n=10) flor 12 weeks.Ten male SD sham-operated rats fed with 18% normal protein diet were used as control (sham group).In addition,mesangial cells were cultured in sera (10%) collected from above animals treated with or without losartan (0.02 mmol/L)for 48 hours.ELISA was applied to detect the level of Ang II,TGF-β1 and fibronectin (FN) in cell medium.Westem blotting was used to determine the protein level of ATI receptor (AT1R)and real-time PCR was used to detect the mRNA level of AT1R,TGF-β1 and FN. Results (1) Nutritional indices including body weight,total protein and albumin had no significant difference in each group. (2) Serum creatinine and 24 h pruteinuria were significantly inceased in nephrectomized groups compared to sham group(P<0.05,respectively).24 h proteinuria was greatly lower in LK group than that in NPD and LPD groups(P<0.05,respectively).(3)LK greatly decteased the level of Ang II[NPD(12.70±0.12)mg/g protein;sham(8.04±0.62)mg/g protein]in supernatant as well as the protein and mRNA expression of AT1R in cultured mesangial cells (P<0.05).(4)NPD serum directly induced higher secretion[FN:sham(20.58±0.46)g/g protein,NPD (39.84±0.06)g/g protein;TGF-β1:sham(10.12±O.56)mg/g protein,NPD(83.85±3.58)mg/g protein] and mRNA expression of FN and TGF-β1 compared with sham group (P<0.05).LPD decreased these increment (P<0.05) and LK showed stronger inhibitory effect (P<0.05). (5)Losartan application sharply reduced FN and TGF-β1 production both in supematant and in mRNA expression in NPD serum treated cells (P<0.05,respectively). Conclusion Low protein diet with α-keto acids supplement directly inhibits the RAS in mesangial cells which may contribute to its beneficial effect on the kidney.

Objective To observe the growing shape and function of Madin-Darby canine kidney (MDCK) cells implanted on the polysilicon nanopore membrane by micro-electro-mechanical system (MEMS). Methods The polysilicon nanomembrane was made by silicon film processed via whirling photoresist, wet etching, electroplating and so on, and then it was coated by extracellular matrix and implanted with MDCK cells. The cell growth shape and function was observed or examined by scanning electron microscope or MTT test and Trypan Blue staining.Results The nanomembrane with regular slit pores was successfully fabricated. Extracellular matrix-coated nanomembrane, especially for collagen Ⅳ coating, was more suitable for MDCK cells to adhere and proliferate without membrane injury. The polysilicon nanomembrane coated with extracellular matrix did not induce the cell death and also not stimulate cells releasing the cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α). Under scanning electron microscope, MDCK cells formed a flat single-cell fusion with tight junction on the surface of polysilicon nanomembrane and there was a large number of microvillus on the top of cells.Conclusion The collagen-coated polysilicon nanomembrane made by MEMS techniques, with no cytotoxicity and good biocompatibility, is valuable to frame the artificial glomerular filtration membrane

Objective To establish a citrate pharmacokinetics model which is applied to evaluate the risk of citrate accumulation in patients with liver dysfunction in the continuous renal replacement treatment (CRRT) with regional citrate anticoagulation (RCA). Methods The source of citrate for extracorporeal anticoagulation, the body clearance and filter elimination of citrate, which were the three major citrate fluxes of systemic citrate level, were combined into a single-pool, first order kinetic equation. The data from a published clinical study of systemic citrate kinetics in the intensive care unit patients with or without liver cirrhosis were adapted and the citrate kinetic equation was applied to predict the risk of systemic citrate accumulation in patients with normal, impaired and absent liver clearance while different RCA-CRRT protocols were carried out. Results The single pool, first order citrate kinetic modeling equation was as follows:Csys=C(0)·e-[(clb+clf)·t/V]+G/CLb+CLf×(1-e-[(clb+clf)·t/V])There was excellent agreement between published citrate measurements and our predictions. Kinetic modeling showed that the plasma citrate concentration of patients with normal citrate body clearance was no more than 1 mmol/L during common RCA-CRRT. The model predicted that when the single pass fractional extraction of citrate on the artificial kidney was above 66％, systemic steady citrate concentration would be among the safe range even in patients of impaired body metabolism of citrate.Conclusions The citrate kinetic model of RCA-CRRT can predict the risk of systemic citrate accumulation and provide the basis for designing the safe RCA-protocols for the patients with impaired body clearance of citrate.

Objective To explore whether the stimulation effect of high phosphate on hyperplasia of human parathyroid cells and hyperparathyroidism through local cyclooxygenase 2 (COX2) up-regulation pathway. Methods Parathyroid glands were collected from 19 uremic patients undergoing parathyroidectomy.Expressions of COX1,COX2 and proliferative cell nuclear antigen (PCNA) of the glands were detected by immunohistochemistry.Primary parathyroid cells were cultured and treated with high or normal phosphate for 48 hours.Then expressions of COX2 and PCNA were detected by Western blotting and real-time PCR. Results Among 62 glands from above 19 patients,43 glands were nodular hyperplasia and 19 diffuse hyperplasia.Both high expressions of COX2 and PCNA were found in these blands.Expression of COX2 was found in both oxyphil and chief cells and was more in the diffuse hyperplasia glands than that in the nodular hyperplasia (P＜0.05).80.60％ and 85.20％ of COX2 positive cells in diffuse hyperplasia glands and nodular hyperplasia also expressed PCNA. High phosphate could stimulate iPTH secretion in vitro (P＜0.05).Expressions of COX2 and PCNA were higher in high phosphate group.(P＜0.05). Conclusion High phosphate may stimulate the hyperplasia of parathyroid cells by up-regulating the local COX2 expression.

Hemodialysis monitoring and information management software was used to establish an intelligent electronic system to manage hemodialysis patients' information,with hardware and software moderations.The electronic information management system for hemodialysis functioned steadily since 2008.This system changed not only the existing medical process of the center,but also contributed to safer treatments,more accurate operations of doctor’ s instructions,and better medical information records as well The results indicate that the electronic information management system in hemodialysis centers not only irnproves work efficiency and management quality significantly,but also effectively ensures the safety and caliber of hemodialysis treatment with less manpower costs.

Objective To report a simple formula to estimate phosphate removal by standard four-hour hemodialysis in Chinese patients.Methods A total of 165 MHD patients in Huashan Hospital were enrolled.Effluent dialysate samples were collected during treatment to estimate the total amount of phosphate removal.Pre-dialysis levels of serum phosphate,potassium (K+),hematocrit(Hct),parathyroid hormone(iPTH),carbon dioxide combining power(CO2CP),alkaline phosphatase (AKP),Kt/V,and ultrafiltration volume,age,gender,dry body weight,blood flow,phosphate clearance of dialyser,phosphate concentration of dialysate at 60 min after the start of HD were obtained.80％ observations were randomly selected for formula building by backward stepwise and the remaining 20％ observations were used to validate the formula.Results The formula was described as Tpo4 =88.6 ×C60-0.03 ×Age + 1.07 ×Gender +0.06 ×Clearance-4.59,where C60 was phosphate concentration in dialysate measured 60 min into HD and Clearance was the phosphate clearance of dialyser.Formula validation further suggested good predictive ability.Conclusion This study derives an approach to quantify phosphate removal by a simple formula,which will be helpful for clinicians to treat patient individually.

Objective To examine the effect and mechanism of high salt diet on the renal medullary cyclooxygenase 2 (COX2) expression and urinary sodium excretion. Methods Thirty male C57BL/6j mice were divided into four groups: (1) normal salt diet group (0.4％NaCl, n=5); (2) high salt diet group (8％NaCl, n=5);(3) Bortezomib+normal salt diet group (n=10);(4) Bortezomib+high salt diet group (n=10). The different groups were pre-treated with saline or bortezomib ,followed by normal salt diet or high salt diet for three days. All the mice were maintained on metabolic cage at the last day and allowed free access to water. Twenty-four hours urine was collected. Body weight, urine volumes were documented. At the end of experiments, mice were sacrificed under anesthesia and the kidneys were harvested for Western blotting and immunohistochemistry. The transgenic mice carrying a luciferase reporter driven by an NF-κB response promoter, HIV long terminal repeat (LTR) (HLL mice) were used to explore the effect of high salt diet on renal medullary NF-κB activity. HLL mice were fed with normal salt diet or high salt diet for 3 days, after which renal medullary luciferase activity was determined using a commercial luciferase assay kit. Luciferase activity was quantified with a luminometer and adjusted for the total amount of proteins. The cellular location of NF-κB was examined using immunohistochemistry of NF-κB p65 staining. Results (1) Western blotting results showed high salt diet significantly increased the COX2 expression in the renal medulla of C57BL/6j mice (P﹤0.05). (2) High salt diet significantly increased NF-κB luciferase reporter activity in the HLL mice renal medullary tissues when compared to normal salt diet (P﹤0.05). The immunohistochemistry of NF-κB p65 showed the expression of NF-κB was mainly in the renal interstitial cells. (3) Western blotting results showed bortezomib inhibited the renal medullar COX2 expression induced by high salt diet (P﹤0.05). (4) Bortezomib decreased the urinary sodium excretion of high salt diet mice (P﹤0.05), but had no change on urine volume. Conclusions High salt diet induce renal medullary COX2 over-expression and activate the activation of NF-κB in renal medullary. Bortezmoib can inhibit the renal medullar COX2 expression induced by high salt diet. The NF-κB pathway activation may involve in the regulation of renal medullar COX2 expression by high salt diet.