Objective To investigate the factors associated with hyporesponsiveness to erythropoietin (EPO) in patients on maintenance peritoneal dialysis (PD). Methods Data of 114 PD patients in our PD center were collected. Patients were divided into three groups according to weekly EPO dose: hyperresponsive, hyporesponsive and normal responsive. Various factors were compared among three groups by linear correlation and ordinal regression analysis to predict EPO resistance. Results As compared to hyperresponsive and normal responsive groups, significantly lower serum hemoglobin [(78.11±13.42) vs (106.28±23.83), (96.31±12.33) g/L], albumin [(33.98±4.78) vs (39.72±4.26), (35.76±4.88) g/L], and significantly higher serum CRP [(26.08±21.66) vs (5.46±1.75), (11.82±5.63) mg/L], ferritin [(371.08±89.38) vs (289.39±76.84), (323.07±62.46) μg/L] were found in hyporesponsive group(all P < 0.01). Erythropoietin resistance index (ERI) was correlated with CRP and albumin. Regression analysis showed that serum albumin，CRP and ferritin were strong predictors of EPO hyporespnsiveness. Conclusions Serum albumin, CRP and ferritin are closely related to hyporesponsiveness. Malnutrition and inflammatory state contribute to EPO hyporesponsiveness.

Objective To analyze the histological changes of bone diseases and to investigate the noninvasive measurements for diagnosing renal osteodystrophy (ROD) in maintenance dialysis patients. Methods Ninety-one patients were selected to receive bone biopsy. The bone samples were stained with HE, toluidine blue and Masson, and were examined with light microscopy. The levels of immunoreactive parathyroid hormone (iPTH), osteoprotegerin (OPG), sRANKL and osteocalcin(OCN) were determined in the patients enrolled from 2004 to 2006. The level of iPTH was measured by radioimmunoassay. OPG and sRANKL were measured by ELISA, and OCN was measured by chemiluminescence. Results The incidence of ROD in the maintenance patients was 100%. According to the histological appearance, 50 cases (54.9% ) were high turnover bone disease(secondary hyperparathyroid bone disease), 9 cases (9.9% ) were low turnover bone diseases(osteomalacia and adynamic bone disease), and 32 cases(35.2% ) were mixed bone disease. The level of iPTH in patients with ROD was significantly increased compared with healthy controls. It was the lowest in low turnover bone diseases. There was no difference among three types of ROD. OPG level was significantly increased compared with healthy controls[（2176.58±1576.08） pmol/L vs（1310.46±1254.00） pmol/L, P<0.05]. The level in high turnover bone diseases was higher than that of the healthy controls[（2261.85±1712.22） pmol/L vs （1310.46±1254.00） pmol/L, P<0.05]. There was no difference among three types of ROD. sRANKL level in high turnover bone disease was significantly increased compared with healthy controls[（0.328±0.524）pmol/L vs （0.084±0.190） pmol/L, P<0.05]. OCN level was also higher than that of the healthy controls (P<0.05), and the OCN level in low turnover ROD was the lowest among three types of ROD. OCN level in mixed ROD was dramatically increased as compared to low turnover ROD [（226.633±66.455） pmol/L vs （193.03±104.269） pmol/L, P<0.05]. Conclusions The histological changes of bone disease can be indicated by iPTH level, but the types of ROD can not be distinguished according to iPTH level neither be differentiated by the levels of OPG, sRANKL and OCN. Bone histomorphometry is still the golden standard for diagnosing renal osteodystrophy.

Objectives To investigate the influence of cytomegalovirus infection after kidney transplantation on the recipients and the associated risk factors of cytomegalovirus infection. Methods Data of 892 kidney transplantation recipients from January 2000 to December 2004 in our department were analyzed retrospectively. All the recipients were divided into case group (with cytomegalovirus infection) and control group (without cytomegalovirus infection). Log-Rank test was used to compare the 1-, 3-, 5-year survival of patients and grafts between two groups. The incidence of complications， the difference of regiment of immunosuppressant and anti-CMV drugs were compared as well. The independent risk factors of cytomegalovirus infection were assessed by Logistic regression analysis. Results One-, 3-, 5-year survival rates of patients in case group were 81.3％, 72.8％ and 54.8％ respectively, while the patients in control group were 96.4％, 91.4％ and 79.9％ respectively, the prior was significantly lower than the latter (Log-Rank value=49.62, P<0.01). One-, 3-, 5-year survival rates of grafts in case group were 71.0％, 66.2％ and 46.1%, while the grafts in control group were 91.5％, 86.6％ and 74.5％ respectively, the prior was significantly lower than the latter as well (Log-Rank value=44.87, P<0.01). The incidence of acute rejection in case group was 24.9%, while it was 13.9% in control group, with significant difference between two groups（χ2＝14.49, P<0.01）. Logistic regression showed that acute rejection, mycophenolate mofetil dose more than 2 g, and usage of ATG/ALG or OKT3 were the independent risk factors of cytomegalovirus infection（OR=1.464, 3.097 and 2.837, P<0.05）. Ganciclovir was the protective factor of cytomegalovirus infection (OR=0.234, P<0.01). Conclusions Cytomegalovirus infection decreases the long-term survival of recipients and grafts in kidney transplantation. Acute rejection, high dose of mycophenolate mofetil, and ATG/ALG or OKT3 are the independent risk factors of cytomegalovirus infection. Prophylactic usage of ganciclovir after kidney transplantation can effectively reduce cytomegalovirus infection.

Objective To identify the clinical characteristics and pathological changes of patients suffered from glomerulonephritis complicating with acute interstitial nephritis(AIN). Methods Twenty one patients of glomerulonephritis complicating with AIN diagnosed by renal biopsy were retrospectively analyzed. Thirty-five pure AIN patients were selected as controls. Results Glomerulonephritis complicating AIN accounted for 37.5% of all the AIN cases. β-lactam antibiotics and Chinese herbs were the major causes of AIN. 76.2% of cases received further examinations due to the elevation of serum creatinine（Scr） during their follow-up of kidney injuries or during routine exams for all kinds of discomforts. Pathological features of AIN were also detected besides glomerular leisions. The impairments of renal interstitia were severe than those of the glomeruli. Eosinophil in the renal interstitia was an important indicator for the diagnosis of AIN. The renal function returned to normal or baseline in 64.7% of the patients of glomerulonephritis complicating with AIN whose follow-up data were available. The median period for renal function restoration was 150 days（compared with 60 days in pure AIN）. But there were no significant differences between these two groups as for the rate of irreversible renal insufficiency during a follow-up period of 2 years. Conclusions Symptoms of AIN in patients of glomerulonephritis complicating with AIN tend to be masked by their glomerular diseases. Renal biopsy is of most importance for the diagnosis. Early diagnosis and treatment leads to satisfactory prognosis.

Objective To study the clinicopathological characteristics and prognosis of asymptomatic IgA nephropathy (IgAN) children with proteinuria and/or microscope haematuria. Methods Clinical and pathological characteristics of 54 children with IgA nephropathy confirmed by renal biopsy were analyzed. These children with IgAN were divided into two groups according to their clinical characteristics at the first onset: asymptomatic IgAN group (AsIgAN) and symptomatic IgAN group (SIgAN). Histologic changes were classified by Lee SM and Katafuchi semiquantitative scoring system. Results Eighteen children were in AsIgAN group and 36 children were in SIgAN group. The degree of proteinuria in SIgAN group [(2.3±2.2) g/d] was higher than that in AsIgAN group [(0.4±0.3) g/d] at the time of biopsy (P<0.05). Although asymptomatic IgAN children were mainly of Lee’s type Ⅰ~Ⅱ, 2 children (11%) were of Lee’s type Ⅳ~Ⅴand 5 cases (27%) presented interstitial injury. Symptomatic IgAN children were mainly of Lee’s type Ⅱ~Ⅲ, there was no significant difference between two groups（P>0.05）. Urine microalbumin was increased in 87% children presented with microscope haematuria. After an average of （26.9±8.8）months follow-up, only one case of Lee’s Ⅴ progressed into renal failure and the others maintained normal renal function. Conclusions Although children with asymptomatic IgAN have minor clinical symptoms, severe renal pathological lesion and poor prognosis also occur. Urine screening helps to detect renal diseases and renal biopsy should be performed in the patients with increased urine microalbumin.

Objective To investigate the pathogenesis of renal lesion in Fechtner syndrome. Methods Pathological characteristics of kidney tissues from Fechtner syndrome patients were explored by HE staining, immunochemistry, immunofluorescence and electron microscopy. Results Immunochemistry analysis showed that non-muscle myosin heavy chain IIA (NMMHC-IIA)was expressed in podocytes of glomeruli and distal convoluted tube, and was faintly expressed in the brush border of proximal tube. Histological examination demonstrated glomerulosclerosis and decreased expression of NMMHC-IIA in abnormal podocytes. Through standard immunofluorecence, the expression of NMMHC-IIA in patient’s podocyte was higher than that in normal podocytes. The fusion of foot process and microvillus were detected by electron microscopy. Conclusion Abnormal NMMHC-IIA aggregates in the glomeruli podocyts and foot process fusion accompanied with appearance of microvillus leads to renal lesion in Fechtner syndrome.

Objective To investigate the effect of parathyroid hormone (PTH) on the transition and connective tissue growth factor (CTGF) expression of human renal proximal tubular epithelial cell line HK-2. Methods The expression of CTGF mRNA and protein of HK-2 cells were measured by real time RT-PCR and Western blot respectively. The effect of PTH on the phenotypic transformation of HK-2 cells was examined by light microscopy. The expression of α-smooth muscle actin (α-SMA) in HK-2 cells was detected by immunofluorescence. Results Basal level of CTGF mRNA and the protein expression were detected in HK-2 cells. PTH up-regulated the expression of CTGF mRNA and protein with the maximal response at the concentration of 10－10 mol/L and the best stimulating time was at 72 h. After exposure to PTH (10－10 mol/L) for 12 hours, the highest level of luciferase activity was 1.96 fold as compared to control（1.888±0.078 vs 0.989±0.030, P＜0.01）. Untreated cells showed negligible expression of α-SMA, whereas α-SMA expression was significantly increased in cells treated with PTH. Conclusion PTH up-regulates CTGF expression and induces transition of HK-2 cells.

Objective To study the effects of acyl-coenzyme A cholesterol acyltransferase inhibitor(ACATI, 58-035) on cholesterol homeostasis in lipid-loaded human mesangial cell line(HMCL) . Methods Oil red O was used to examine the lipid droplet. MTT was performed to detect the cell proliferation. High performance liquid chromatography (HPLC) was used to measure intracellular free cholesterol (FC) and cholesterol ester(CE). Western blot was used to demonstrate the protein level. Real-time PCR was performed to detect the mRNA expression. Results In HMCL loaded with 100 mg/L of low density lipoprotein(LDL), 10 mg/L 58-035 significantly inhibitted the formation of lipid droplets and CE mass (ratios over control, 1.91±0.36 and 1.07±0.30 respectively, P<0.01) without toxic effect. It further enhanced the ACAT1 protein expression (ratios over control, 1.27 and 1.77 respectively) without significant influence on mRNA level, since the activity of ACAT1 p1 promoter by transient transfection was not affected by either LDL or ACATI. 100 mg/L LDL down-regulated the mRNA of LDL receptor(LDLR) (ratio over control, 0.08±0.02, P<0.01)and up-regulated that of ATP binding cassette transporter 1(ABCA1) (ratio over control, 2.97±0.39, P<0.01). The mRNA expression of ABCA1 was further up-regulated (ratio over control 4.41±1.27, compared with LDL group P<0.05), and LDLR was further down-regulated(ratio over control 0.04±0.005, compared with LDL group P<0.01) in the presence of 10 mg/L ACATI 58-035. Conclusions The CE mass in lipid-loaded HMCL can be decreased in the presence of ACATI, accompanied by further down-regulation of LDLR mRNA expression and up-regulation of ABCA1 protein and mRNA expression. It is physiological feedback to inhibit free cholesterol accumulation to maintain cholesterol homeostasis.

Objective To study the effect of fosinopril on the expression of NADPH oxidase subunit p22phox mRNA and the extracellular matrix (ECM) accumulation in the kidneys of rats with diabetes mellitus. Methods Diabetic rats induced by streptozotocin were randomly divided into control group(DM group) and fosinopril group (fosinopril 10 mg·kg-1·d-1) (DM+Fosin group) and treated for 12 weeks. Expression of p22phox mRNA of NADPH oxidase in kidneys was measured by RT-PCR. The expression of fibronectin was studied by immunohistochemistry and matrix metalloproteinases 9 activity was detected by Zymography. Meanwhile, the kidney hypertrophy index, serum creatinine level and 24-hour urinary protein excretion were evaluated. Results The expression level of p22phox mRNA in the kidneys of DM+Fosin group rats was decreased by 45% than that of DM group at week 4 (P<0.05). At week 8 fosinopril significantly decreased the expression of glomerular and tubulointerstitial fibronectin by 52.5% and 42.9% respectively (P<0.05), while increased MMP-9 activity by 29.6% (P<0.05) compared with DM group. Fosinopril significantly decreased 24-hour urinary protein excretion of diabetic rats from week 8. Serum creatinine level, 24-hour urinary protein excretion and kidney hypertrophy index were significantly decreased by 35.9％, 50.2％ and 17.2％ in rats of DM+Fosin group than those of DM group at week 12 (P<0.05). Fosinopril did not affect blood sugar significantly. Conclusion Fosinopril has beneficial effect on diabetic nephropathy partly through inhibiting the expression of NADPH oxidase p22phox mRNA.

Objective To explore whether the inhibited expression of fibrocystin by RNA interference can increase epidermal growth factor (EGF)-induced cell proliferation and its possible mechanism. Methods A stable PKHD1-silenced HEK 293 cell line was established. Cell proliferation rate, intracellular Ca2+ concentration and extracellular signal-regulated kinase 1/2 (ERK1/2) activity were assessed after treatment with EGF, verapamil and Bay K8644. Results The proliferation rate of PKHD1-silenced HEK-293 cells was found to be significantly higher after EGF stimulation compared to the control HEK 293 cell(231.5% vs 152.8%, P＜0.01). PKHD1-silencing lowered the intracellular Ca2+ concentration and caused EGF-induced ERK1/2 overactivation in the cells（P＜0.01）. When cells were treated with verapamil for 4 hours to lower the intracellular Ca2+ concentration, the cell proliferation rate was significantly increased after 20 ng EGF for 24 hours. The verapamil treatment increased the level of activated ERK1/2 in EGF-treated cells. An increase of intracellular Ca2+ in PKHD1-silenced cells repressed the EGF-dependent ERK1/2 activation and the hyperproliferative response to EGF stimulation. Conclusions Inhibition of fibrocystin can cause EGF-induced excessive proliferation through decreasing intracellular Ca2+ resulting in EGF-induced ERK1/2 activation. The loss of fibrocystin may lead to abnormal proliferation in kidney epithelial cells and cyst formation in ARPKD through modulation of intracellular Ca2+ concentration.