Podocyte autophagy is associated with foot process effacement and proteinuria in patients with minimal change nephrotic syndrome

Autophagy is a cellular mechanism involved in the bulk degradation of proteins and turnover of organelle. Several studies have shown the significance of autophagy of the renal tubular epithelium in rodent models of tubulointerstitial disorder. However, the role of autophagy in the regulation of human glomerular diseases is largely unknown. The current study aimed to demonstrate morphological evidence of autophagy and its association with the ultrastructural changes of podocytes and clinical data in patients with idiopathic nephrotic syndrome, a disease in which patients exhibit podocyte injury. The study population included 95 patients, including patients with glomerular disease (minimal change nephrotic syndrome [MCNS], n = 41; idiopathic membranous nephropathy [IMN], n = 37) and 17 control subjects who underwent percutaneous renal biopsy. The number of autophagic vacuoles and the grade of foot process effacement (FPE) in podocytes were examined by electron microscopy (EM). The relationships among the expression of autophagic vacuoles, the grade of FPE, and the clinical data were determined. Autophagic vacuoles were mainly detected in podocytes by EM. The microtubule-associated protein 1 light chain 3 (LC3)-positive area was co-localized with the Wilms tumor 1 (WT1)-positive area on immunofluorescence microscopy, which suggested that autophagy occurred in the podocytes of patients with MCNS. The number of autophagic vacuoles in the podocytes was significantly correlated with the podocyte FPE score (r = -0.443, p = 0.004), the amount of proteinuria (r = 0.334, p = 0.033), and the level of serum albumin (r = -0.317, p = 0.043) in patients with MCNS. The FPE score was a significant determinant for autophagy after adjusting for the age in a multiple regression analysis in MCNS patients (p = 0.0456). However, such correlations were not observed in patients with IMN or in control subjects. In conclusion, the results indicated that the autophagy of podocytes is associated with FPE and severe proteinuria in patients with MCNS. The mechanisms underlying the activation of autophagy in association with FPE in podocytes should be further investigated in order to elucidate the pathophysiology of MCNS

IgA Nephropathy Complicated with X-linked Thrombocytopenia

Renal involvement is occasionally observed in Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT). It has been reported that galactose-deficient IgA is a closely linked to IgA nephropathy (IgAN), suggesting that patients with XLT/WAS associated with reduced galactosylation on serum IgA are susceptible to IgAN. It is necessary to pay more attention to patients with IgAN due to the potential complication with XLT/WAS. We here present a patient of XLT complicated with mild IgAN who underwent tonsillectomy combined with steroid pulse therapy to achieve complete clinical remission

Urine Trefoil Factors as Prognostic Biomarkers in Chronic Kidney Disease

Introduction. Trefoil factor family (TFF) peptides are increased in serum and urine in patients with chronic kidney disease (CKD). However, whether the levels of TFF predict the progression of CKD remains to be elucidated. Methods. We determined the TFF levels using peptide-specific ELISA in spot urine samples and performed a prospective cohort study. The association between the levels of urine TFFs and other urine biomarkers as well as the renal prognosis was analyzed in 216 CKD patients (mean age: 53.7 years, 47.7% female, 56.9% with chronic glomerulonephritis, and mean eGFR: 58.5 ml/min/1.73 m2). Results. The urine TFF1 and TFF3 levels significantly increased with the progression of CKD stages, but not the urine TFF2 levels. The TFF1 and TFF3 peptide levels predicted the progression of CKD ≥ stage 3b by ROC analysis (AUC 0.750 and 0.879, resp.); however, TFF3 alone predicted CKD progression in a multivariate logistic regression analysis (odds ratio 3.854, 95% confidence interval 1.316–11.55). The Kaplan-Meier survival curves demonstrated that patients with a higher TFF1 and TFF3 alone, or in combination with macroalbuminuria, had a significantly worse renal prognosis. Conclusion. The data suggested that urine TFF peptides are associated with renal progression and the outcomes in patients with CKD

Serum cystatin C is an independent biomarker associated with the renal resistive index in patients with chronic kidney disease

<div><p>Cystatin C is a cysteine protease inhibitor that is produced by nearly all human cells. The serum level of cystatin C is a stronger predictor of the renal outcome and the risk of cardiovascular events than the creatinine level. The resistive index (RI) on renal Doppler ultrasonography is a good indicator of vascular resistance as well as the renal outcomes in patients with chronic kidney disease (CKD). However, it is unclear whether serum cystatin C is associated with signs of vascular dysfunction, such as the renal RI. We measured the serum cystatin C levels in 101 CKD patients and investigated the relationships between cystatin C and markers of vascular dysfunction, including the renal RI, ankle-brachial pulse wave velocity (baPWV), intima-media thickness (IMT), and cardiac function. The renal RI was significantly correlated with the serum cystatin C level (p < 0.0001, r = 0.6920). The serum cystatin C level was found to be a significant determinant of the renal RI (p < 0.0001), but not the baPWV, in a multivariate regression analysis. The multivariate odds ratio of the serum cystatin C level for a renal RI of more than 0.66 was statistically significant (2.92, p = 0.0106). The area under the receiver-operating characteristic curve comparing the sensitivity and specificity of cystatin C for predicting an RI of more than 0.66 was 0.882 (cutoff value: 2.04 mg/L). In conclusion, the serum cystatin C level is an independent biomarker associated with the renal RI in patients with CKD.</p></div

The correlation between the resistive index (RI) and various parameters.

<p>The relationships between the RI and patient age (years) (A), estimated glomerular filtration rate (eGFR) (mL/min/1.73 m2) (B), albuminuria (mg/day) (C), cystatin C (mg/L) (D) and markers of systemic atherosclerosis, including the ankle-brachial pulse wave velocity (baPWV) (E) and maximum intima-media thickness (IMT) (F), are shown. The RI was positively correlated with age, albuminuria, and cystatin C, and inversely correlated with eGFR (A-D). Regarding the markers of systemic atherosclerosis, baPWV and maximum IMT were positively correlated with RI (E, F).</p

The multivariate odds ratios for the resistive index (RI: 0.66) among patients with CKD.

<p>The values are displayed as the odds ratio (OR) (solid boxes) with 95% confidence intervals (CIs) (horizontal limit lines). For continuous variables, the unit of change is given in parentheses. Adjusted for age and eGFR. SBP, systolic blood pressure; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate.</p

Serum cystatin C is an independent biomarker associated with the renal resistive index in patients with chronic kidney disease - Fig 3

<p><b>The ROC curves comparing the sensitivity and specificity of cystatin C (A), albuminuria (B), BNP (C) and e’ (D) for predicting a resistive index (RI) 0.66.</b> The AUC values for the ROC curve when cystatin C, albuminuria, BNP and e’ were used to detect an RI of 0.66 were 0.882 (p < 0.0001), 0.705 (p = 0.0012), 0.865 (p < 0.0001) and 0.722 (p = 0.0007), respectively.</p

Baseline characteristics of the study subjects.

<p>Baseline characteristics of the study subjects.</p