Objective To investigate the characteristics of infecting pathogens, their changes and antimicrobial susceptibilities on CAPD related peritonitis in our peritoneal dialysis(PD) center in the past 15 years. Methods Two hundred and six CAPD related peritonitis episodes in 145 patients from 2000 to 2005 were analyzed and compared with 109 episodes from 1991 to 2000. The causative pathogens, their antimicrobial susceptibilities and outcomes on CAPD related peritonitis from the two periods were retrospectively reviewed and compared. Results Culture negative rate decreased from 60.6% in 1990 s to 47.6% in the last five years(P = 0.031). Among culture positive peritonitis episodes, the incidence of gram positive bacteria (GPB) peritonitis increased from 25.6% to 39.8% (P = 0.059). This was mainly due to a significant increase in coagulase-neagative staphylococcus peritonitis, which significantly increased from 4.7% to 26.9% (P = 0.01). Gram negative bacteria(GNB) peritonitis decreased slightly (44.2% vs 34.3%, P=0.322). The incidence of Klebsiella pneumoniae peritonitis significantly decreased (14.0% vs 3.7%, P = 0.023), while Pseudomonas aeruginosa and Escherichis coli peritonitis rates slightly increased (4.7% vs 9.3%, P = 0.338; 7% vs 18.7%, P = 0.072). The decrease of fungal peritonitis rate was not significant (30.2% vs 17.6%,P = 0.123). The comparison of clinical outcomes showed an improvement of total recovery rate from 68.8% in 1990 s to 73.9% for 2000-2005(P = 0.09). The catheter removal rate decreased from 19.2% to 14.3% (P = 0.238), and the mortality from 10.1% to 5.4% (P = 0.118). In both periods, fungal peritonitis had the poorest results, which all the patients either withdrew from PD or died. Conclusions Compared with that in 1990 s, the culture positive rate for CAPD related peritonitis in 2000-2005 has been greatly improved. Coagulase-negative staphylococcus is the most common causative pathogen. The mortality and catheter removal rate have been markedly reduced in the last five years. Fungal peritonitis is the most important reason for patients′ dropout.

Objective To propose a new blood purification modality-hemodialysis with plasma-based dialysate (HD-PBD) plus high volume hemofiltration (HVHF) for patients with liver failure, and to evaluate the effect of this treatment on plasma cytokines. Methods Twelve patients with liver failure were included in this study. All patients received HD-PBD therapy in the first 6 hours, and then were treated with HVHF for 24 hours with the same filter (AV600). The levels of TNF-α, IL-1β, IL-6 and IL-8 in plasma before and after HD-PBD plus HVHF for 6 and 24 hours were examined respectively by ELISA, and changes of clinical parameters were observed at the same time point. Serum bilirubin, total bile acids (TBA), serum ammonia, blood urea nitrogen (BUN) and serum creatinine(Scr) were detected before and after treatment. Arterial blood gas analysis and the concentration of electrolytes were monitored before and after treatment. Results (1)HD-PBD for 6 hours was more effective than HVHF for 24 hours in removal of serum bilirubin and TBA(P < 0.05). (2)Serum ammonia, BUN, Scr, arterial blood HCO3-,PCO2,PO2 and electrolytes did not show significant difference before and after HD-PBD (P > 0.05), but these parameters significantly changed before and after HVHF(P < 0.05). (3)The average level of serum bilirubin was sharplydecreased after HVHF for 24 h following HD-PBD(P < 0.05). (4)After HD-PBD plus HVHF, there was a marked reduction of the plasma levels of TNF-α, IL-6 and IL-8. Conclusions HD-PBD plus HVHF, a newly proposed modality for patients with liver failure, can effectively decrease serum bilirubin, TBA, BUN, Scr, ammonia and cytokines, and adjust water-electrolyte as well as acid-alkali balance. It is a low-cost, safe, simple and convenient therapy.

Objective To evaluate the efficacy of HD02 hemodialysis monitor by means of ultrasound dilution method in surveillance of arteriovenous fistula. Methods Re-circulation, blood flow of fistula and cardiac output of 90 maintenance hemodialysis (MHD) patients were measured by HD02 hemodialysis monitor during hemodialysis session. Concerning factors of fistula blood flow were analyzed. Results Fistula re-circulation(>5%) occurred in 4 patients (3.33%). Blood flow (Qa) less than 500 ml/min was found in 21 patients(23.33%), and more than 2000 ml/min in 3 patients (3.33%). The logistic regression analysis revealed that age, sex, time of hemodialysis, time of fistula creation and mean arterial pressure were not significantly correlated, but low cardiac output and diabetes were significantly correlated to the decrease of fistula blood flow. Cardiac output less than 4 L/min was found in 33 patients(36.67%), suggesting that low cardiac output status existed in some MHD patients during hemodialysis session. Cardiac color Doppler was performed in 8 low cardiac output status patients and the result showed changes of cardiac function and structure such as interventricular septum pachynsis, cardiac valve calcification, back-streaming and left ventricle diastolic insufficiency. Conclusions Ultrasound dilution is a simple non-invasive surveillance method for hemodialysis fistula. The re-circulation rate is low when A-V fistula obtaining enough blood flow.Low cardiac output and diabetes are significantly correlated with the decrease of fistula blood flow.

Objective To study the effect of dialysis adequacy,microinflammation and residual renal function on nutritional status of hemodialysis patients. Methods One hundred and fourteen patients were enrolled in this study. Kt/V,β2-MG and serum iPTH were measured as markers of hemodialysis adequacy. Nutritional evaluation included MQSGA, Alb, Hb, TF, IGF-1, IGFBP -3 and anthropometrics such as HGS, BSF, TSF, MAC, MAMC and AMA. Serum IL-6, TNF-α and CRP were detected to assess microinflammation. Urinary volume of 24 hours was measured to investigate the residual renal function (RRF). Results (1)There were different correlations and regressive associations of Kt/V, iPTH and β2-MG with HGS, MAMC, AMA, Alb, Hb, nPCR, IGF-1 and MQSGA respectively. (2) There were significant correlations and regressive associations of RRF to HGS, TSF, MAMC, Alb, nPCR and IGF-1 within the first year of hemodialysis. (3) There were different correlations and regression relationships of IL-6, TNF-α and CRP with HGS，MAMC，AMA，Alb，TSF，Hb，nPCR，IGF-1 respectively. (4) Multivariate analysis showed that Kt/V, iPTH, IL-6, TNF-α, β2-MG and RRF were influencing factors, among them, Kt/V,iPTH,IL-6 and TNF-α were independent predictors of nutritional status. Conclusions Hemodialysis adequacy and microinflammation may impact on nutritional status. Residual renal function may be involved in nutritional status in the first year of hemodialysis. Kt/V, iPTH, IL-6 and TNF-α are independent factors affecting nutritional status.

Objective To investigate the apoptosis of T lymphocytes,the expression of Bcl-2,Fas on the peripheral blood T lymphocytes in end stage renal disease patients;and to explore the characteristics of Th1 /Th2 profile and the influence of dialysis membranes with different permeability on the apoptosis of T lymphocytes of maintenance hemodialysis patients. Methods The study included 10 non-dialyszed(ND)patients,45 maintenance hemodialysis patients with cellulose acetate(CA) membranes(13), low-flux polusulfone(PS-LF) membranes(16), high-flux polusulfone (PS-HF)membranes(16) and 8 healthy volunteers(C). The apoptosis of T lymphocytes,expression of Bcl-2,Fas on peripheral blood T lymphocytes cultured with phytohemagglutinin (PHA) stimulation for 24 hours were measured by flow cytometry and immunohistochemical. ELISA was performed for detecting the levels of IFN-γ and IL-4 in culture supernatants. Results In ESRD patients,the apoptosis of T lymphocytes was greater than that of group C. Group CA was greater than group PS-HF and group PS-LF(P < 0.05). The expression of Bcl-2 on T lymphocytes in ESRD patients was lower than that of group C(P < 0.05). There was negative correlation between the T lymphocytes apoptosis and Bcl-2. The expression of Fas on T lymphocytes in ESRD patients was greater than that of group C(P < 0.05),and it was positive correlated with T lymphocytes apoptosis. The level of IFN-γ of ESRD patients was decreased significantly compared with that in group C(P < 0.05), and there was negative correlation between T lymphocytes apoptosis and IFN-γ. IL-4 was increased in ESRD patients(P < 0.05) and it was positive correlated with T lymphocytes apoptosis. Conclusions The accelerated apoptosis of T lymphocytes in ESRD patients may be related to the expression of Bcl-2 and Fas of T lymphocytes. ESRD patients show a suppressed secretion of IFN-γ and an increased secretion of IL-4. T lymphocytes apoptosis of maintenance hemodialysis patients is influenced not only by the biocompatibility but also by the permeability of the dialysis membrane.

Objective To explore the effect of ox-LDL, MCP-1, CD68 on the survival of arteriovenous fistula in radial arteries of uremic patients. Methods Segments of radial arteries were obtained from 23 uremic subjects (29~68 years old) in the initial operation of arteriovenous fistula prior to hemodialysis. The deposit of ox-LDL and the expression of MCP-1,CD68 on the vascular wall were measured by immunohistochemistry. The survival time of arteriovenous fistula was followed by survival analysis. Results COX regression revealed that each of these risk factors,ox-LDL,MCP-1, CD68, played an important role in the survival time of arteriovenous fistula when they entered the model independently. The hazard ratios were 1.008 (P=0.008,95% CI:1.002064~1.014104), 1.007(P=0.000, 95%CI: 1.003853~1.010966), and 1.098496 (P=0.000, 95%CI: 1.047909~1.151526)respectively. When all the three factors entered the COX regression model, the whole model was still founded. MCP-1 and CD68 still played important roles in the survival of arteriovenous fistula. The hazard ratios were 1.006(P=0.025) and 1.113(P=0.001) respectively. With the hazard ratio of 0.997, ox-LDL did not reach the statistic significance(P=0.414). Conclusions The more deposit of ox-LDL and the more expression of MCP-1, CD68 on the vascular wall, the more shortened survival time of arteriovenous fistula. Particularly, the inflammation is the independent risk factor for the prognosis of arteriovenous fistula in uremic patients.

Objective To investigate the effect of angiotensin Ⅱ (AngⅡ) type 1 receptor blocker losartan on the cyclooxygenase 2(COX-2) expression in metabolic syndrome(MS)kidney. Methods Seven-week-old male obese Zucker rats, a model of MS, were randomly divided into losartan treated and untreated group, and lean Zucker rats were used as controls. The obese Zucker rats of treated group received losartan for 4 months continuously. COX-2 expression was examined for all rats after 4 months. AngⅡ-stimulated mesangial cells and cortical tissue from AngⅡ-infused C57BL/6 mouse kidney by osmotic minipumps were used in this study. RNA and protein were obtained from renal cortical tissue or mesangial cells for RT-PCR and Western blot. Results Compared to the lean controls, obese Zucker rats showed a significant increase of COX-2 expression in the renal cortical tissue and these abnormalities were prevented by administration of losartan. Furthermore,the direct stimulation of AngⅡ increased COX-2 expression in mesangial cells in vitro and renal cortical tissue in vivo. Conclusions MS-induced COX-2 expression in the kidney is regulated by AngⅡ. Losartan as a non COX-2 inhibitor can protect MS kidney, at least in part, by inhibition of COX-2 activation.

Objective To investigate the effects of AGE-modified bovine serum albumin (AGE-BSA) on the expression of connective tissue growth factor(CTGF) in human renal proximal tubular epithelial cells(HK-2 cells) and to explore the possible role. Methods HK-2 cells were cultured in vitro with indicated concentration of AGE-BSA or BSA. The localization of the receptor for AGEs (RAGE) in HK-2 cells was detected by immunofluorescent staining. The expression of CTGF protein was examined by Western blotting. The production of TGF-β1 was measured by ELISA and Western blotting. Results RAGE was expressed in the plasma and membrane of HK-2 cell line. In the AGE-BSA group, the expression of CTGF protein significantly increased in a time- and dose-dependent manner. CTGF expression in AGE-BSA 8 h,24 h,48 h and 72 h groups was 117%,138%,257% and 339% of 0 h group respectively,while in AGE-BSA 20,50 and 100 mg/L groups was 186%,240% and 287% of 0 mg/L group respectively. AGE-BSA also induced the secretion of TGF-β1 in a dose-dependent manner in 24 hours and the concentration of AGE-BSA between 0 and 100 mg/L. AGE-induced up-regulation of CTGF protein at 48 hours was blocked partially by neutralizing RAGE antibodies and TGF-β1 antibodies. Conclusions Human renal proximal tubular epithelial cells express RAGE. The up-regulation of the expression of CTGF induced by AGE-BSA may be partially mediated through a RAGE-TGF-β1- dependent pathway.

Objective To explore the roles of reactive oxygen species(ROS) and TGF-β1 in aldosterone-induced PAI-1 production. Methods Quiescent rat mesangial cells (MCs) were treated by aldosterone. The level of ROS in MCs induced by aldosterone was measured by confocal laser scanning microscopy and the TGF-β1 activity in the supernatant of culture was measured by mink lung epithelial cell (Mvllu) proliferation inhibition MTT assay. Then, before the addition of aldosterone, MCs were pretreated with NAC or TGF-β1 neutralizing antibody to decrease cellular ROS or inhibit activity of TGF-β1 induced by aldosterone respectively. PAI-1 mRNA was examined by semi-quantification RT-PCR and PAI-1 protein by Western blotting. Results The intracellular ROS induced by aldosterone increased by 5-fold compared to that of control group, and the activity of TGF-β1 stimulated by aldosterone increased markedly. TGF-β1 neutralizing antibody and NAC effectively decreased aldosterone-induced PAI-1 mRNA expression by 30% and 32%, and PAI-1 protein expression by 21% and 11%, respectively. However, neither TGF-β1 neutralizing antibody nor NAC alone could regulate aldosterone-induced PAI-1 mRNA and protein expression to normal level in 24 hours. Conclusions ROS and TGF-β1 play important roles in up-regulation of aldosterone-induced PAI-1 in MCs. ROS and TGF-β1 are not the exclusive pathway of PAI-1 expression induced by aldosterone in MCs.

Objective To investigate whether mesenchymal stem cells can promote the recovery of acute renal tubular damage induced by mercuric chloride and to explore its possible mechanism. Methods Acute renal failure rat model was established by intraperitoneal injection of mercuric chloride. SD rats were randomly divided into three groups which were MSCs injection group, saline infusion group and normal control group. Seven days later, the changes of rat weight, survival, renal function and pathology were observed; PCNA, ED-1 and GFP were detected by immunohistochemistry; The expression of cytokines in kidney and the distribution of GFP plasmid-transfected MSCs in kidney were examined by RT-PCR. Results MSCs infusion ameliorated the decline of rat weight, survival, renal function, and pathological changes. PCNA and ED-1 positive cells in MSCs group were fewer than those in saline group. Expression of growth factors EGF,PDGF,HGF were obviously up-regulated and pre-inflammatory cytokines TNF-α was significantly reduced in MSCs-treated kidneys. GFP-labelled MSCs occurred occasionally in renal interstitium of MSCs-treated rats, but not in renal tubules. Conclusions Bone marrow mesenchymal stem cells can promote the recovery of acute renal tubular epithelial cells damage caused by mercuric chloride. The mechanism may partly depend on regulating the excretion of cytokines in renal microenvironment rather than completely depend on their differentiation to tubular cells.