Yong-Xi Chen

Analyzing fatal cases of Chinese patients with primary antineutrophil cytoplasmic antibodies-associated renal vasculitis: a 10-year retrospective study.

Background/Aims: Primary antineutrophil cytoplasmic antibodies (ANCA)-associated systemic vasculitis (AASV) used to have poor prognosis, and renal involvement is its most common manifestation. Few studies have been published focusing on AASV patients with poor prognosis. Methods: From 1997 to 2006, 101 patients with ANCA-associated renal vasculitis (70 microscopic polyangiitis, MPA; 14 Wegener’s granulomatosis, WG; 3 Churg-Strauss syndrome, CSS; 14 renal limited vasculitis, RLV) were diagnosed in Shanghai Ruijin Hospital and 26 deaths were recorded among them. Patients’ data were retrospectively analyzed. Results: Patients with WG, MPA and RLV made up for 23.1% (6/26), 65.4% (17/26) and 11.5% (3/26) of all deaths. No deaths were observed among CSS patients. Infection alone accounted for 13 deaths. Infection together with pulmonary involvement of active vasculitis accounted for 3. Organ-specific involvement of active vasculitis alone caused 8 deaths. Others died of acute myocardial infarction or gastric carcinoma. Compared with patients who survived, nonsurvivors had more severe renal insufficiency and older age (p < 0.01). There was no significant difference regarding clinical presentation at diagnosis and cause of death between patients who survived first remission-induction treatment and those who did not. Infection remained the major cause of death. Conclusion: Infection is the major cause of death in patients with ANCA-associated renal vasculitis, and treatment response might not correlate to severity of disease in patients with poor prognosis. Rational use of immunosuppressants could improve the prognosis.

Phosphoproteomic Study of Human Tubular Epithelial Cell in Response to Transforming Growth Factor-Beta-1-Induced Epithelial-to-Mesenchymal Transition

Background: Transforming growth factor-β (TGF-β)-induced epithelial-to-mesenchymal transition (EMT) plays an important role in renal fibrosis and progression of chronic kidney disease (CKD). Phosphorylation of proteins is essential to TGF-β signaling. We applied isobaric tags for relative and absolute quantification (iTRAQ) technology to profile the phosphoproteins in tubular epithelial cells in response to TGF-β-induced EMT in order to further study molecular events. Methods: HK-2 cells were treated with TGF-β1 to induce EMT. The cells were divided into a control group (without TGF-β1 treatment) and a TGF-β1-treated group. Phosphoproteins from two groups were extracted and differentially labeled with iTRAQ reagents and processed by 2D-nano-HPLC-MS/MS. Validating of iTRAQ analysis was performed by western blot. Bioinformatic analysis was performed by on-line databases. Results: By iTRAQ-2D-nano-HPLC-MS/MS, 38 differentially expressed phosphoproteins were identified which included 19 up-regulated phosphoproteins and 19 down-regulated phosphoproteins. Western blot confirmed up-regulation of phosphorylated moesin and HSP90α. Bioinformatic analysis suggested that the majority of proteins were located in the nucleus and endoplasmic reticulum lumen. The phosphoproteins were categorized into 17 molecular function classifications. Nucleic acid binding protein, cytoskeletal protein and chaperone were the major categories of molecular function. A biological network was built to analyze interaction between up-regulated proteins. Conclusion: We demonstrate a TGF-β1-mediated post-transcriptional regulation of EMT in tubular epithelial cells. Phosphorylation of moesin and HSP90α might play a role in TGF-β-induced EMT.

Propylthiouracil-induced Antineutrophil Cytoplasmic Antibody (ANCA)-associated Renal Vasculitis Versus Primary ANCA-associated Renal Vasculitis: A Comparative Study

Objective. Renal involvement is frequently present in primary antineutrophil cytoplasmic antibody-associated small-vessel vasculitis (AAV) as well as propylthiouracil (PTU)-induced AAV. We analyzed the characteristics of patients with PTU-induced AAV with renal involvement and investigated the differences of the 2 diseases. Methods. Thirty-six patients with PTU-induced AAV, diagnosed from 1997 to 2010, were enrolled for study. Their data were compared with those of 174 patients with primary AAV diagnosed at the same time. Renal involvement was present in all patients. Results. There was a prominent proportion of young women with PTU-induced AAV (p < 0.01). They had lower levels of proteinuria and serum creatinine and higher estimated glomerular filtration rate (p < 0.01, p < 0.01, and p < 0.01, respectively). Clinical immunological abnormalities were less severe in patients with PTU-induced AAV. Patients with PTU-induced AAV had less organ involvement and lower Birmingham Vasculitis Assessment Score than patients with primary AAV (p < 0.01). Renal biopsies showed a lower proportion of glomeruli with crescents (p < 0.01). Interstitial inflammation was less severe in patients with PTU-induced AAV (p < 0.05). Similarly, interstitial fibrosis and tubular atrophy were less severe in patients with PTU-induced AAV (p < 0.01, p < 0.05, respectively). Renal survival and total survival were better in patients with PTU-associated vasculitis (p < 0.05, p = 0.01). Conclusion. Clinical and histopathological abnormalities were less severe in patients with PTU-induced AAV and most of them had a good prognosis.

Histopathological Classification and Renal Outcome in Patients with Antineutrophil Cytoplasmic Antibodies-associated Renal Vasculitis: A Study of 186 Patients and Metaanalysis

Objective. Renal vasculitis is one of the most common manifestations of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) and renal histology is a key predictor of the outcome. A new histopathologic classification was proposed and validated, but the results are still debated. Methods. We performed a retrospective analysis to validate the histopathologic classification and performed a metaanalysis to evaluate its predictive value. There were 186 patients with ANCA-associated renal vasculitis diagnosed at Ruijin Hospital who were enrolled in the retrospective study. The metaanalysis considered the data for 1601 patients. Results. In our retrospective study, patients with focal class had the best renal outcome while patients with mixed class had the worst (p < 0.001). Metaanalysis showed that patients with focal class had better renal outcome than did those with crescentic class [risk ratio (RR) 0.23, 95% CI 0.16–0.34, p < 0.00001], with no evidence of heterogeneity (I2 = 0%, p = 0.96). Patients with crescentic class had better renal outcome than did those with sclerotic class (RR 0.52, 95% CI 0.41–0.64, p < 0.00001), with no evidence of heterogeneity (I2 = 2%, p = 0.43). We did not find statistical significance regarding renal outcome between mixed and crescentic classes (RR 1.14, 95% CI 0.91–1.43, p = 0.27), with no evidence of heterogeneity (I2 = 23%, p = 0.19). The retrospective study showed that lung and upper respiratory tract involvement were the most common extrarenal manifestations. Conclusion. We demonstrated the clinical utility of histopathologic classification in determining renal outcome in patients with AAV. Metaanalysis showed that patients with focal class had the best outcome while sclerotic class had the worst.

Clinicopathological Characteristics and Outcome of Chinese Patients with Thrombotic Thrombocytopenic Purpura-Hemolytic Uremic Syndrome: A 9-Year Retrospective Study

Background: The pathogenesis of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is unclear and the prognosis is poor. Few studies have been published focusing on Chinese patients with TTP-HUS. We performed a retrospective study on the clinical characteristics and outcome of Chinese patients with TTP-HUS. Method: Patients with TTP-HUS, admitted to our hospital from 1998 to 2006, were retrospectively analyzed. Results: There were 26 females and 6 males in our study. Fifteen patients had systemic lupus erythematosus (SLE)-associated TTP-HUS; 2 had pregnancy-associated TTP-HUS; 1 had antiphospholipid syndrome-associated TTP-HUS; 2 had drug-associated TTP-HUS; 4 had malignant angionephrosclerosis- associated TTP-HUS; 3 had vasculitis-associated TTP-HUS, and the remaining 5 had idiopathic TTP-HUS. Twenty-six patients had acute kidney injury and 21 had nephrotic syndrome. Hypertension was found in 31 patients. For the treatment, 15 patients had plasmapheresis, 12 had continuous veno-venous hemodiafiltration and 14 had hemodialysis. Eighteen patients were treated with intravenous immunoglobulin. Corticosteroids were used in patients with idiopathic TTP-HUS. For the patients with SLE-associated TTP-HUS, corticosteroids and immunosuppressant were used. Outcome was poor: 6 patients died; 17 recovered from renal insufficiency; 5 progressed to chronic renal failure, and 4 were dependent on hemodialysis. Conclusions: Most of our patients had secondary TTP-HUS. SLE-associated TTP-HUS is the most common form of TTP-HUS. Early diagnosis and treatment can improve prognosis. An immunosuppressant together with corticosteroids could improve prognosis in some patients.

Identification of Nestin as a Urinary Biomarker for Acute Kidney Injury

Objectives: Acute kidney injury (AKI) is a common complication in hospitalized patients and the incidence of AKI is rapidly increasing. Despite the advances in treatment of AKI, many patients still progress to end-stage renal disease and depend on dialysis. Therefore, early diagnosis and adequate treatment of AKI could improve prognosis. Methods: We established rat models of AKI induced by cisplatin nephrotoxicity and renal ischemia-reperfusion (I/R). Urine samples were collected, labeled with isobaric tags for relative and absolute quantification agents, and then subjected to nano-LC-MS/MS-based proteomic analysis. Results of the proteomic study were confirmed by Western blot. We also performed RNAi to silence nestin and investigate its role in renal I/R injury. We then validated its clinical application by studying urine nestin levels in AKI patients with cardiovascular surgeries. Results: Our proteomic analysis showed that fetuin-A, nestin, hamartin and T-kininogen were differentially expressed in the urine samples of rats after cisplatin or I/R treatment. Western blot confirmed the differential expression of these proteins in animal models and ELISA confirmed the differential expression of nestin in human urine samples. To explore the expression of nestin in the development of AKI, our results showed that nestin was primarily detected in the glomeruli and barely detected in tubular cells but increased in tubular cells during I/R- and cisplatin-induced AKI. The urine nestin-to-creatinine ratio increased earlier than serum creatinine in AKI patients with postcardiovascular surgeries. The role of nestin in AKI might be related to the p53 signaling pathway. Conclusions: Thus, our results demonstrated that urinary nestin could be a urinary biomarker for patients with AKI and its role in AKI might be related to the p53 signaling pathway.

Urinary MicroRNA-30c-5p and MicroRNA-192-5p as potential biomarkers of ischemia–reperfusion-induced kidney injury:

Early detection of acute kidney injury is difficult due to lack of known biomarkers; previous studies have tried to identify new biomarkers for detecting acute kidney injury at an early stage. MicroRNA, a 21-23 nucleotide noncoding RNA molecule, has emerged as a desirable marker in the diagnosis and prognosis of various diseases. This study aims to identify the expression profile of microRNA in ischemia–reperfusion-induced kidney injury and determine the possibility of using the candidate microRNA as biomarker for the detection of I/R-induced kidney injury. Based on the established rat model of I/R-induced kidney injury, a microarray analysis of rat urine was performed at the beginning of operation (0 h) as well as 72 h post operation. To validate the results, urine samples from 71 patients who underwent cardiac surgery were collected, after which urinalysis was conducted to determine the microRNA concentration. An alternative expression profile of microRNAs was detected in rat urine. The quantitative validation of microRNA showed that the expression of miR-30c-5p, miR-192-5p, and miR-378a-3p was elevated significantly in urine post operation, which was consistent with those of the microarray analysis and earlier than kidney injury molecule-1 (KIM-1). In patients with acute kidney injury, increased levels of miR-30c-5p and miR-192-5p were also detected 2 h post operation, and miR-30c-5p showed preferable diagnostic value compared with protein-based biomarkers. In conclusion, an aberrant expression profile of microRNA was detected in rat urine based on the established ischemia–reperfusion animal model. Both miR-30c-5p and miR-192-5p served as important potential diagnostic markers for I/R-induced kidney injury. Impact statement Firstly, one differentiating factor in our study is that the candidate miRNAs were screened in a controlled animal model rather than in patients with acute kidney injury (AKI) to ensure the purity of the cause of disease and to avoid possible effects of comorbidities on the spectrum of urine miRNA. This ensured the presence of only the relevant candidate miRNA (that associated with I/R injury); and what’s more, the alterative expression of miR-192-5p and miR-30c-5p in animal model, patients with AKI, and cell model was confirmed simultaneously, which is likely to be more convincing. Secondly, the candidate miRNAs were screened sequentially at regular time points, which covered the initiation, progression, and partial repair stages, thus ensuring that no significant miRNAs were omitted in the screening process, and miR-biomarkers in 2 h post operation showed preferable diagnostic performance.

Role of Moesin in Renal Fibrosis

Background Renal fibrosis is the final common pathway of chronic kidney disease (CKD). Moesin is a member of Ezrin/Radixin/Moesin (ERM) protein family but its role in renal fibrosis is not clear. Method Human proximal tubular cells (HK-2) were stimulated with or without TGF-β1. Moesin and downstream target genes were examined by real-time PCR and western blot. Phosphorylation of moesin and related signaling pathway was investigated as well. Rat model of unilateral ureteral obstruction (UUO) was established and renal moesin was examined by immunohistochemistry. Moesin in HK-2 cells were knocked down by siRNA and change of downstream genes in transfected HK-2 cells was studied. All animal experiments were reviewed and approved by the Ethics Committee for animal care of Ruijin Hospital. Result HK-2 cells stimulated with TGF-β1 showed up-regulated level of α-SMA and down-regulated level of E-Cadherin as well as elevated mRNA and protein level of moesin. In rat model of UUO, renal moesin expression increased in accordance with severity of tubulointerestital fibrosis in the kidneys with ureteral ligation while the contralateral kidneys were normal. Further study showed that TGF-β1 could induce phosphorylation of moesin which depended on Erk signaling pathway and Erk inhibitor PD98059 could block moesin phosphorylation. Effects of TGF-β1 on moesin phosphorylation was prior to its activation to total moesin. RNA silencing studies showed that knocking down of moesin could attenuate decrease of E-Cadherin induced by TGF-β1. Conclusion We find that moesin might be involved in renal fibrosis and its effects could be related to interacting with E-Cadherin.

Clinical experience with nadroparin in patients undergoing dialysis for renal impairment

Dialysis procedures are life‐sustaining renal replacement therapies indicated for patients with limited or no kidney function. The formation of clots in the extracorporeal circuit during dialysis is an undesirable event. Anticoagulation is therefore routinely practiced in this context. Unfractionated heparin (UFH) is largely used in dialysis patients. However, except in patients with an elevated risk of bleeding, the 2002 European Best Practice Guidelines Expert Group on Hemodialysis recommended the use of low–molecular‐weight heparins over UFH, in view of their equal efficacy, improved safety, and easy handling. Low–molecular‐weight heparins comprise several drugs, differing in a number of pharmacological and clinical properties. This manuscript reviews the data obtained with nadroparin, a low–molecular‐weight heparin studied extensively in dialysis patients. Thus, several studies investigated the benefit of nadroparin vs. UFH, other low–molecular‐weight heparins, or citrate in patients undergoing intermittent hemodialysis. Overall, they showed that a single intravenous bolus dose of nadroparin, adjusted according to body weight, was effective and safe for maintaining the patency of the extracorporeal circuit during intermittent hemodialysis sessions lasting up to 6 hours, in both adults and children with end‐stage renal failure. In contrast to UFH, nadroparin required no laboratory monitoring of anticoagulant activity owing to the reliable anticoagulant response following its administration. Compared with UFH, nadroparin was beneficial in terms of lipid and possibly bone parameters. Nadroparin administered by a bolus dose, followed by a continuous infusion was also shown to be effective and safe in patients undergoing continuous renal replacement therapy for acute renal failure.

Analyzing Chinese patients with post-operative acute kidney injury.

Abstract Background: To investigate clinical characteristics and risk factors of Chinese patients with post-operative acute kidney injury (PO-AKI). Methods: Patients with PO-AKI in Ruijin Hospital from December 1997 to December 2005 were retrospectively studied. Results: Patients’ mean age was 62.2 ± 18.1 years. There were 111 males and 57 females. The mean serum creatinine at diagnosis was 370.41 ± 320.92 μmol/L and the mean estimated glomerular filtration rate was 33.56 ± 24.24 mL/min. For the outcome of the patients, 38 died and the mortality rate was 22.6%. There were 17 patients (10.1%) with Acute Dialysis Quality Initiative-RIFLE (risk-injury-failure-loss-end classification) phase R, 21 (12.5%) with phase I, and 130 (77.4%) with phase F. There was no significant difference in mortality regarding patients who underwent different types of surgeries. For the risk factors related to PO-AKI, acute tubular necrosis (ATN) increased relative risk of mortality PO-AKI (odds ratio = 7.089, 95% confidence interval = 2.069–24.288, p < 0.001). Multivariate regression models showed that ATN had a positive correlation with mortality of PO-AKI. Conclusions: PO-AKI is one of the most common causes of AKI in patients who underwent operations. Special attention should be paid to risk factors related to PO-AKI in order to improve prognosis.