Lining Wang

Modified Glomerular Filtration Rate Estimating Equation for Chinese Patients with Chronic Kidney Disease

The Modification of Diet in Renal Disease (MDRD) equations provide a rapid method of assessing GFR in patients with chronic kidney disease (CKD). However, previous research indicated that modification of these equations is necessary for application in Chinese patients with CKD. The objective of this study was to modify MDRD equations on the basis of the data from the Chinese CKD population and compare the diagnostic performance of the modified MDRD equations with that of the original MDRD equations across CKD stages in a multicenter, cross-sectional study of GFR estimation from plasma creatinine, demographic data, and clinical characteristics. A total of 684 adult patients with CKD, from nine geographic regions of China were selected. A random sample of 454 of these patients were included in the training sample set, and the remaining 230 patients were included in the testing sample set. With the use of the dual plasma sampling (99m)Tc-DTPA plasma clearance method as a reference for GFR measurement, the original MDRD equations were modified by two methods: First, by adding a racial factor for Chinese in the original MDRD equations, and, second, by applying multiple linear regression to the training sample and modifying the coefficient that is associated with each variable in the original MDRD equations and then validating in the testing sample and comparing it with the original MDRD equations. All modified MDRD equations showed significant performance improvement in bias, precision, and accuracy compared with the original MDRD equations, and the percentage of estimated GFR that did not deviate >30% from the reference GFR was >75%. The modified MDRD equations that were based on the Chinese patients with CKD offered significant advantages in different CKD stages and could be applied in clinical practice, at least in Chinese patients with CKD.

Evaluation of the Chronic Kidney Disease Epidemiology Collaboration equation for estimating glomerular filtration rate in the Chinese population

BACKGROUND Previous studies have indicated that the performance of glomerular filtration rate (GFR) estimation equations vary according to the races of the target population. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation has not been validated in the Chinese population including patients with chronic kidney disease (CKD) and healthy controls. METHODS A total of 977 adult persons (682 patients with CKD and 295 healthy volunteers) from nine renal institutes of university hospitals located in nine geographic regions of China were enrolled in the study. A diagnostic test study comparing the CKD-EPI two-level and four-level race equation, the Modification of Diet in Renal Disease (MDRD) Study equation and the modified MDRD equation for Chinese (the Chinese equation). The (99m)Tc- diethylenetriamine pentaacetic acid dual plasma clearance was used as a reference method for measuring GFR. RESULTS The mean age of participants was 48.3 ± 16.0 years and 479 (49.0%) were male. The CKD-EPI two-level race equation and the Chinese equation performed better than the MDRD Study equation and CKD-EPI four-level race equation, with less bias (median difference between estimated GFR and reference GFR, 0.2 and 0.3 versus -2.4 and 3.0 mL/min/1.73 m(2)), improved precision (interquartile range of the difference, 20.5 and 20.8 versus 23.4 and 20.5 mL/min/1.73 m(2)) and greater accuracy (percentage of estimated GFR within 30% of reference GFR, 73.4 and 73.0% versus 69.8 and 70.1%). CONCLUSIONS The CKD-EPI two-level race equation and the Chinese equation performed similarly in the Chinese population, and both performed better than the MDRD Study equation and the CKD-EPI four-level race equation.

Urinary mannose-binding lectin is a biomarker for predicting the progression of immunoglobulin (Ig)A nephropathy.

Complement system activation is associated with immunoglobulin A nephropathy (IgAN) activity and progression. The aim of the present study was to investigate the importance of urinary mannose‐binding lectin (MBL), at the time of renal biopsy, for evaluating disease severity and predicting the progression of IgAN. A total of 162 patients with biopsy‐proven IgAN were enrolled and 50 healthy individuals were selected as normal controls. Urinary MBL was measured by sandwich enzyme‐linked immunosorbent assay (ELISA) and normalized for urinary creatinine concentration. Urinary MBL was significantly higher in IgAN patients than that in normal controls, and elevated as histopathological phenotypes upgraded. Urinary MBL was correlated significantly with the well‐known clinical predictors for the prognosis of IgAN; that is, renal function (represented by serum creatinine and estimated glomerular filtration rate), proteinuria and arterial hypertension. Urinary MBL was demonstrated to be correlated with the histopathological parameters which have independent value in predicting renal outcome of IgAN according to the Oxford classification; that is, mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis. More importantly, non‐remission patients at the end of follow‐up had significantly higher levels of urinary MBL compared with patients in remission. In conclusion, urinary MBL can be a reliable non‐invasive biomarker for evaluating disease severity and predicting the prognosis of IgAN. This is the first report on this issue. However, our conclusions should be verified further in large‐scale studies with long‐term follow‐up.

Inhibition of autophagy increased AGE/ROS-mediated apoptosis in mesangial cells.

The aim of our study was to investigate the role of autophagy, a homeostatic process involved in the lysosomal degradation of damaged cell organelles and proteins, in regulating the survival of mesangial cells treated with advanced glycation end products (AGEs). In the present study, AGEs induced mitochondrial depolarization and led to mitochondrial-dependent apoptosis in mesangial cells, as shown by the loss of the mitochondrial membrane potential; increased Bax processing; increased Caspase-9, Caspase-3 and PARP cleavage; and decreased Bcl-2 expression. Meanwhile, AGEs also triggered autophagy flux in mesangial cells, as confirmed by the presence of autophagic vesicles, the conversion of LC3II/LC3I and the increase/decrease in Beclin-1/p62 expression. Interestingly, this study reported apparent apoptosis and autophagy that were dependent on reactive oxygen species (ROS) production. Scavenging ROS with N-acetyl-l-cysteine could prevent the appearance of the autophagic features and reverse AGE-induced apoptosis. Moreover, AGE-triggered mitophagy, which was confirmed by the colocalization of autophagosomes and mitochondria and Parkin translocation to mitochondria, played a potential role in reducing ROS production in mesangial cells. Additionally, inhibition of autophagy significantly enhanced AGE-induced cell apoptosis. Taken together, our data suggest that ROS were the mediators of AGE-induced mesangial cell apoptosis and that autophagy was likely to be the mechanism that was triggered to repair the ROS-induced damage in the AGE-treated cells and thereby promote cell survival. This study provides new insights into the molecular mechanism of autophagy involved in AGE-induced apoptosis in mesangial cells.

Prevalence and associated factors of emotional and behavioural problems in Chinese school adolescents: a cross-sectional survey.

BACKGROUND Emotional and behavioural problems are key health issues in adolescence. The aim of this study was to evaluate the prevalence of emotional and behavioural problems in Chinese school adolescents and to explore associated factors. METHODS This cross-sectional study was conducted during the period of November/December 2009. A questionnaire including the Strengths and Difficulties Questionnaire (SDQ) self-reported version, and the characteristics of child (age, gender, only child and study pressure), parents (parent-adolescent relationship and parental expectations) and families (living area, family structure, socio-economic status and negative life events) was distributed to our study population. A total of 5220 Chinese adolescents (aged 11-18) from 30 public schools in Liaoning province completed the questionnaire. Multivariate logistic analysis was used to explore the factors associated with emotional and behavioural problems. RESULTS The average problem score was 11.28 (SD = 5.86) and the 10.7% scored above the cut-off for emotional and behavioural problems. Factors that increased the risk of having emotional and behavioural problems were: poor parent-adolescent relationship, experiencing more negative life events, older age, having study pressure, living in rural areas, boys and lower parental expectations. CONCLUSIONS The prevalence of emotional and behavioural problems among Chinese adolescents was lower level compared with those reported in other countries. We found parent-adolescent relationship, negative life events and age to be the strongest contributing factors of emotional and behavioural problems.

Protective effects of tubular liver-type fatty acid-binding protein against glomerular damage in murine IgA nephropathy

BACKGROUND Liver-type fatty acid-binding protein (L-FABP) in proximal tubules was reported to have renoprotective roles in experimental tubulointerstitial diseases via its anti-oxidative properties. Since tubuloglomerular cross-talk was recently discussed in the progression of renal diseases, to investigate whether tubular L-FABP may have an impact on the progression of glomerular damage, we induced IgA nephropathy (IgAN) in mice (Tg) transgenically tubular overexpressing human L-FABP (hL-FABP). METHODS We reconstituted IgAN by bone marrow transplantation (BMT) from IgAN-prone mice into Tg and wild-type (WT) mice. Renal damage was evaluated at 6 and 12 weeks after BMT. During in vitro experiments, mesangial cells (MC) were stimulated by aggragated IgA (AIgA), and their supernatants (AIgA-MC medium) were collected. Stable cell line of mouse proximal tubular cell (mProx) transfected with or without hL-FABP gene was cultured with the AIgA-MC medium. RESULTS Although mesangial IgA deposition and serum IgA level were not different between WT (WT/ddY) and Tg (Tg/ddY) recipients, WT/ddY mice showed a significantly higher urinary albumin level and mesangial matrix expansion with a significantly higher glomerular damage score. Furthermore, CD68 + macrophage infiltration was also significantly attenuated in Tg/ddY mice. Up-regulation of renal hL-FABP was associated with significant suppression of renal heme oxygenase-1 (HO-1) expression and accumulation of 4-hydroxy-2-nonenal (4-HNE) and MCP-1 expression in Tg/ddY mice. In vitro experiments showed that AIgA-MC medium and recombinant TNF-α significantly up-regulated hL-FABP expression, which was partially blocked by anti-TNF-α antibody, and major mediators of oxidative stress (HO-1 and 4-HNE) and inflammation (MCP-1). Importantly, such up-regulation of the mediators in mProx with hL-FABP was significantly suppressed much more than that in mProx. CONCLUSIONS Tubular L-FABP activated by MC-origin humoral factors may lessen progression of glomerular damage at early stages of IgAN by reducing oxidative stress and inflammatory mediators.

Glomerular mannose-binding lectin deposition is a useful prognostic predictor in immunoglobulin A nephropathy

There is accumulating evidence to support a hypothesis of the activation of the lectin complement pathway in immunoglobulin A nephropathy (IgAN). The glomerular deposition of mannose‐binding lectin (MBL), an initiator of the lectin pathway, has been identified, but its clinical significance has not been defined consistently. The aim of the present study was to investigate the value of glomerular MBL deposition as a useful histological biomarker in evaluating the severity and predicting the prognosis of IgAN. We included all consecutive patients with biopsy‐proven primary IgAN from December 2008 to July 2010. Renal deposition of MBL was detected by immunofluorescence. The biopsy material from 131 patients (72 men) was thus used for MBL staining. The deposition of MBL was observed in a predominantly mesangial pattern in 45 patients (34·35%), which presented as global or segmental deposition. Compared with the patients without glomerular MBL deposition, those with glomerular MBL deposition had more severe proteinuria, decreased renal function, lower levels of serum albumin and a greater possibility of hypertension at the time of renal biopsy; they had more severe histological changes according to the Oxford classification (i.e. mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis), and their ratio presented an increase as the histopathological phenotypes segregated according to Lees classification; furthermore, the follow‐up data demonstrated that they had a lower renal remission rate. In conclusion, glomerular MBL deposition may predict a poor prognosis, and thus can be a new prognostic factor in IgA nephropathy.

Ursolic acid improves podocyte injury caused by high glucose

Background Autophagy plays an important role in the maintenance of podocyte homeostasis. Reduced autophagy may result in limited renal cell function during exposure to high glucose conditions. In this study we investigated the effects of ursolic acid (UA) on autophagy and podocyte injury, which were induced by high glucose. Methods Conditionally immortalized murine podocytes were cultured in media supplemented with high glucose and the effects of the PI3K inhibitor LY294002 and UA on protein expression were determined. miR-21 expression was detected by real-time RT-PCR. Activation of the PTEN-PI3K/Akt/mTOR pathway, expression of autophagy-related proteins and expression of podocyte marker proteins were determined by western blot. Immunofluorescence was used to monitor the accumulation of LC3 puncta. Autophagosomes were also observed by transmission electron microscopy. Results During exposure to high glucose conditions, the normal level of autophagy was reduced in podocytes, and this defective autophagy induced podocyte injury. Increased miR-21 expression, decreased PTEN expression and abnormal activation of the PI3K/Akt/mTOR pathway were observed in cells that were cultured in high glucose conditions. UA and LY294002 reduced podocyte injury through the restoration of defective autophagy. Our data suggest that UA inhibits miR-21 expression and increases PTEN expression, which in turn inhibits Akt and mTOR and restores normal levels of autophagy. Conclusions Our data suggest that podocyte injury is associated with reduced levels of autophagy during exposure to high glucose conditions, UA attenuated podocyte injury via an increase in autophagy through miR-21 inhibition and PTEN expression, which inhibit the abnormal activation of the PI3K/Akt/mTOR pathway.

circHLA-C Plays an Important Role in Lupus Nephritis by Sponging miR-150

Circular RNAs (circRNAs) participate in the pathogenesis of various diseases by sponging microRNAs (miRs). However, the roles of circRNAs remain unreported in glomerular diseases. We previously reported that miR-150 positively correlated with renal chronicity index in patients with lupus nephritis (LN). We aimed to investigate renal circRNA profiling and the interaction between circRNAs and miR-150 in LN patients. Six renal biopsies from untreated female patients with LN class IV and five normal kidney tissues from urology patients were used for circRNA sequencing. 171 circRNAs with 2-fold differential expression were identified in LN compared with normal control. Ten selected circRNAs were validated by real-time qPCR, and seven circRNAs showed the same significant increases as the sequencing results. circHLA-C positively correlated with proteinuria (R = 0.92, p < 0.01), serum creatinine (R = 0.76, p = 0.08), renal activity index (R = 0.88, p < 0.05), and crescentic glomeruli (R = 0.93, p < 0.01). Renal circHLA-C increased 2.72-fold, and miR-150 decreased 66% in LN compared with normal control (p < 0.05). Bio-informatic analysis predicted miR-150 was regulated by circHLA-C and displayed one perfect match seed between circHLA-C and miR-150. The renal miR-150 showed a tendency of negative correlation with circHLA-C in LN patients. In conclusion, circHLA-C may play an important role in the pathogenesis of lupus nephritis by sponging miR-150.

Nrf2 deficiency promotes the progression from acute tubular damage to chronic renal fibrosis following unilateral ureteral obstruction

Background Nuclear factor erythroid 2-related factor 2 (Nrf2) is a central mediator of cellular responses to oxidative stress. We hypothesized that Nrf2 modulates progression from acute tubular damage to renal fibrosis. We asked whether Nrf2 deletion increases renal injury in mice following unilateral ureteral obstruction (UUO). Methods We explored the time course of renal injury and Nrf2 expression in Nrf2+/+ mice following UUO. We compared Nrf2+/+ and Nrf2-/- mice following UUO in tubular damage, transdifferentiation [vimentin, proliferating cell nuclear antigen (PCNA)], fibrosis [fibronectin, α-smooth muscle actin (SMA)], antioxidative and inflammatory responses. We studied Nrf2 in renal biopsies of patients with acute, subacute and chronic tubulointerstitial nephritis (TIN). Results In Nrf2+/+ mice, renal Nrf2 expression and Nrf2-regulated glutamate-cysteine ligase catalytic (Gclc) and heme oxygenase-1 (Ho-1) were elevated, and renal injury occurred between 2 and 14 days after UUO. On Day 2 following UUO, in Nrf2-/- mice compared with Nrf2+/+ mice, tubular damage, apoptotic cell numbers, cleaved caspase3 and cleaved-poly ADP-ribose polymerase were increased. On Day 5, protein levels of vimentin and PCNA and the co-expressed cells of both proteins were increased. On Day 14, fibronectin and α-SMA protein levels were increased. Nrf2 deletion decreased expression of antioxidative genes (Gclc and Ho-1) and increased expression of inflammatory response genes (Tgfβ, Tnf, IL-6, IL-1β and F4/80). Finally, Nrf2 expression was upregulated in renal biopsies of patients with TIN. Conclusions Following UUO, Nrf2 deficiency increased tubular damage, transdifferentiation, fibrosis and inflammatory response while decreasing antioxidative responses. The renal protective role of Nrf2 in the development of tubulointerstitial fibrosis in UUO may be mediated by antioxidative and anti-inflammatory pathways.