AIM: To investigate the role of Smad7 in the Smad2 expression induced by transforming growth factor-?_1(TGF-?_1) in rat peritoneal mesothelial cells(PMCs).METHODS: Rat PMCs were cultured at different doses of TGF-?_1 (0,1.25,2.5,10 ?g/L) for different time(0,5,15,30,60,120 min).PCDNA3-Smad7 was then transfected into cultured rat PMCs by lipofectamine,and the cells were stimulated like the above.Endogenous Smad2 and Smad7 expression was evaluated by RT-PCR and Western blotting.RESULTS: TGF-?_1 induced increase in Smad2 mRNA and protein expression at 5 min,peaked at 30 min,and declined to baseline levels at 120 min, which was in a time-dependent manner.TGF-?_1 also induced Smad7 mRNA expression at 5 min,and then declined,down to the lowest at 30 min,but at 60 min it increased again.Smad2,Smad7 mRNA and protein expression induced by TGF-?_1 were also dose-dependent.After transfection,overexpressions of Smad7 mRNA and protein in rat PMCs were observed,which did not decline with time.The expression of Smad2 mRNA significantly decreased by 33%,56%,67%,71%,63% and 57%(P

Objective To explore the role and mechanism of microRNA-15b in the regulation of epithelial-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs).Methods PCR assay was used to determine the expression of microRNA-15b in the HMrSV5 induced by 138mmol/L high glucose for 24 h.MicmRNA-15b mimic or inhibitor was transfected into human peritoneal mesothelial cells (HMrSV5) to over-express or down-regulate microRNA-15b.The cells were then incubated with 138 mmol/L high glucose for 24 h,and the expressions of E-cadherin(E-Cad),Vimentin (VIM),Fibronectin(FN) and Smad7 were detected by real-time PCR and Western blotting respectively.Results microRNA-15b in the HMrSV5 ceils was over-expressed and down-regulated.Increased level of microRNA-15b was obtained in HMrSV5 cells treated with high glucose.In vitro,high glucose led to the up-regulation of vimentin as well as fibronectin and the down-regulation of E-cadherin in HMrSV5 cells (all P ＜ 0.05),which indicated EMT and fibrosis.Suppression of microRNA-15b by transfection with microRNA-15b inhibitor partially reversed the EMT and fibrosis changes (P ＜ 0.05),while over-expression of microRNA-15b by transfection with microRNA-15b mimic obviously enhanced the EMT and fibrosis changes (P ＜ 0.05).Conclusions MicroRNA-15b mediates high glucose induced EMT in human peritoneal mesothelial cells by the inhibition of Smad7 possibly.MicroRNA-15b maybe a new target for the prevention and treatment of peritoneal fibrosis during peritoneal dialysis (PD).

AIM: To investigate the effects of advanced glycation end products on activation of Smad signaling pathway and collagenⅠ synthesis in proximal tubular epithelial cells.METHODS: Advanced glycation end products(AGE-BSA) were prepared by incubation of bovine serum albumin(BSA) with D-glucose.Normal rat proximal tubular epithelial(NRK52E) cells were cultured in RPMI-1640 medium with AGE-BSA.Phosphorylation and nuclear translocation of Smad2/3 were examined by immunocytochemistry.Levels of TGF-?_1 in supernatant of cell culture were measured by enzyme-linked immunosorbent assay(ELISA).Expression of TGF-?_1,Smad2,Smad3 and Smad7 mRNA were detected by RT-PCR.Expression of ?-SMA,E-cadherin and collagenⅠproteins were detected by Western blotting.RESULTS: AGE-BSA induced Smad2/3 phosphorylation and nuclear translocation,two peaks occured at 30 min(68% vs 16%,P

Objective:To explore the relationship between metabolic acidosis and cardiac valve calcification in maintenance hemodialysis (MHD) patients in the Pearl River Delta Region.Methods:Patients on MHD greater than 3 months who were treated in 10 blood purification centers in the Pearl River Delta Region from July 1 to September 30, 2019 were selected for this multicenter cross-sectional study. Based on a Doppler ultrasound, MHD patients were further divided into non-valve calcification group and valve calcification group. The demographics data, frequency of dialysis, blood pressure, single pool Kt/V(spKt/V), dialysis medications and laboratory data were collected and compared. Spearman correlation analysis was used to analyze the correlation between serum carbon dioxide combining power (CO 2CP) and cardiac valve calcification. Multivariate logistic regression model was used to analyze the influencing factors of cardiac valve calcification. Results:A total of 664 MHD patients were included in this study, with age of (57.0±14.2) years old and dialysis age of 43.0 (22.3, 71.7) months, including 395 males (59.5%) and 269 females (40.5%). Among them, there were 119 patients (17.9%) with diabetes and 186 patients (28.0%) with dialysis 2 times per week. There were 329 patients (49.5%) in the valve calcification group, and 335 patients (50.5%) in the non-valve calcification group. Compared to those in non-valve calcification group, valve calcification group had longer duration of dialysis, higher proportion of patients with dialysis 2 times per week, higher levels of diastolic blood pressure, fasting blood glucose, intact parathyroid hormone and ferritin, higher proportion of patients with blood CO 2CP<19 mmol/L (median CO 2CP), higher proportion of patients on usage of calcium channel blocker, angiotensin converting enzyme inhibitor/angiotensin receptor blocker, α-receptor blocker, β-receptor blocker, calcitriol and lanthanum carbonate (all P<0.05), while the levels of spKt/V, hemoglobin, serum CO 2CP, corrected calcium, blood phosphorus, blood alkaline phosphatase, albumin, total cholesterol, triacylglycerol, low-density lipoprotein, high-density lipoprotein, transferrin saturation, and the proportion of patients on usage of sevelamer and cinacalcet were lower (all P<0.05). Spearman analysis showed significant negative correlation between serum CO 2CP and valve calcification ( rs=-0.697, P<0.001). Multivariate logistic regression analysis showed that dialysis performed twice a week ( OR=2.789, 95% CI 1.232-6.305, P=0.014), blood total cholesterol ( OR=1.449, 95% CI 1.014-2.071, P=0.042), CO 2CP<19 mmol/L ( OR=22.412, 95% CI 10.640-47.210, P<0.001) were the influencing factor of valve calcification in MHD patients. Conclusions:MHD patients with cardiac valve calcification have significant acid loading. Metabolic acidosis is an independent influencing factor for cardiac valve calcification in MHD patients.

AIM: To observe the effect of antibiotic treatment on the inflammatory mediator expression in peritoneum and the peritoneal transport function in rats with acute peritonitis, and explore its mechanisms. METHODS: Eighty-six SD rats were randomly divided into three groups. Control group (n=28) were treated with PBS (ip), peritonitis group (n=28) and treatment group (n=28) were challenged with the E.coli (ip), but at 3 h and 9 h gentamicin was given (ip) in treatment group. Seven rats of every group were randomly sacrificed at 24 h, 48 h, 72 h and 7 d. Peritoneal equilibration test (PET) was did before they were killed. Leukocyte count, pathological changes and the expression of CD45, NF-?B, IL-1?, TNF-? in peritoneum were examined. RESULTS: (1)The blood leukocytes in peritonitis group decreased strikingly, but did not change obviously in other two groups. The peritoneal fluid leukocytes in peritonitis group increased significantly from 24 h to 72 h, while in treatment group, it enhanced more strikingly than peritonitis group at 24 h, and recovered earlier. (2) Both in peritonitis group and treatment group, the expression of activated NF-?B, IL-1?, TNF-? and CD45 increased significantly, but the treatment group was lower than model group at 48 h and 72 h. The mRNA level of IL-1? and TNF-? had the same trend as their protein expression. (3) Compared with the control group, UF and D/D_0 Glu decreased significantly in model group and treatment group, and D/PTP increased dramatically. The D/P TP in treatment group lowered obviously compared with peritonitis group, while the net UF and D/D_0 Glu had not significant difference between treatment group and model group. CONCLUSION: Antibiotic treatment can partly decrease the expression of inflammatory mediators in peritoneum of rats with acute peritonitis and also can improve the protein transport ability to some extent, but can not improve the peritoneal ultrafiltration and the glucose transport function.

Objective:To explore the relationship between low serum albumin levels and its duration on first episode of peritonitis in peritoneal dialysis (PD) patients.Methods:PD patients who were regularly followed up in the Pearl River Delta region from September 1, 2000 to July 6, 2021 in Shunde Hospital of Southern Medical University, Nanfang Hospital of Southern Medical University, and Foshan First People′s Hospital were retrospectively selected. The patients were divided into low serum albumin group (LSA group, mean albumin<35 g/L), moderate serum albumin group (MSA group, 35 g/L≤mean albumin<40 g/L) and high serum albumin group (HSA group, mean albumin≥40 g/L) according to the mean albumin of the patients, and the differences among the three groups were compared. The Kaplan-Meier survival analysis method was used to compare the risk of peritonitis events in different mean albumin groups and different durations of hypoalbuminemia. The multivariate Cox regression model was used to analyze the relationship between serum albumin levels and duration of hypoalbuminemia and new-onset peritonitis.Results:A total of 1 853 PD patients were included in this study, aged (49.72±15.34) years, and 1 036(55.9%) males. There were 551 patients (29.7%) in the LSA group, 920 patients (49.7%) in the MSA group, and 382 patients (20.6%) in the HSA group. The median follow-up was 37 (15, 66) months and there were 508 patients (27.4%) with new-onset peritonitis during the follow-up. Compared with the LSA group, the incidence of new peritonitis in the MSA group and HSA group was lower ( χ2=14.053, P<0.001; χ2=21.857, P<0.001), but there was no significant difference in the incidence of new peritonitis between the HSA group and MSA group. The Kaplan-Meier survival analysis showed that the cumulative incidence of peritonitis in the LSA group was significantly higher than that in the MSA group and HSA group (Log-rank χ2=22.128, P<0.001). Compared with PD patients with normal serum albumin, the patients with longer duration of hypoalbuminemia tended to have a higher incidence of new peritonitis. Multivariate Cox regression analysis showed that the mean albumin<35 g/L (LSA group/MSA group, HR=1.495, 95% CI 1.198-1.866, P<0.001; LSA group/HSA group, HR=1.459, 95% CI 1.104-1.928, P=0.008) was an independent risk factor of new-onset peritonitis in PD patients and the prolongation of duration of hypoalbuminemia had a significantly higher risk of new-onset peritonitis ( HR=1.013, 95% CI 1.003-1.024, P=0.014). Conclusion:The mean albumin<35 g/L and prolong duration of hypoalbuminemia are independent risk factors of PD-related peritonitis in PD patients.

OBJECTIVETo explore the value of baseline serum alkaline phosphatase (ALP) for predicting 2-year fracture in patients with chronic kidney disease (CKD) on maintenance dialysis.

METHODSA total of 139 patients with CKD undergoing maintenance dialysis in our hospital were enrolled in this study. According to the median serum ALP level, the patients were divided into high ALP and low ALP groups. The demographic and clinical data of the patients including dialysis duration, serum calcium level, serum phosphorus level, and serum intact parathyroid hormone level were recorded, and their bone mineral density of the femur and the lumbar spine was measured using dual energy X-ray absorptiometry. The patients were followed up for 2 years and fracture events were recorded. The risk factors of fracture were analyzed using logistic regression analysis, and their predictive value for fracture was analyzed using receiver-operating characteristic (ROC) curve.

RESULTSThe mean baseline serum ALP level was 132.55±167.68 U/L in these patients, significantly higher than that in the normal population (=2.816, =0.006). Baseline serum ALP level was negatively correlated with the bone mineral density of the lumbar spine (=-0.203, =0.006) and the femur (=-0.196, =0.021). Fractures occurred in 21 (15.1%) of the patients during the 2-year follow-up, and the fracture rate was significantly higher in patients with high ALP levels. Logistic regression analysis identified serum ALP level as an independent risk factor of fracture (OR: 1.010, =0.001, 95%CI: 1.004-1.016). The areas under the ROC curve were 0.900 and 0.768 for serum ALP level and intact parathyroid hormone level in predicting 2-year fractures, respectively.

CONCLUSIONSSerum ALP may serve as a good indicator for predicting 2-year fractures in patients with CKD on maintenance dialysis.