The correlation of urinary podocytes and podocalyxin with histological features of lupus nephritis

Abstract

Objectives The objective of this study was to test the correlation of urinary podocyte number (U-Pod) and urinary podocalyxin levels (U-PCX) with histology of lupus nephritis. Methods This was an observational, cross-sectional study. Sixty-four patients were enrolled: 40 with lupus nephritis and 24 without lupus nephritis (12 lupus nephritis patients in complete remission and 12 systemic lupus erythematosus patients without lupus nephritis). Urine samples were collected before initiating treatment. U-Pod was determined by counting podocalyxin-positive cells, and U-PCX was measured by sandwich ELISA, normalized to urinary creatinine levels (U-Pod/Cr, U-PCX/Cr). Results Lupus nephritis patients showed significantly higher U-Pod/Cr and U-PCX/Cr compared with patients without lupus nephritis. U-Pod/Cr was high in proliferative lupus nephritis (class III±V/IV±V), especially in pure class IV (4.57 (2.02-16.75)), but low in pure class V (0.30 (0.00-0.71)). U-Pod/Cr showed a positive correlation with activity index ( r=0.50, P=0.0012) and was independently associated with cellular crescent formation. In contrast, U-PCX/Cr was high in both proliferative and membranous lupus nephritis. Receiver operating characteristic analysis revealed significant correlation of U-Pod/Cr with pure class IV, class IV±V and cellular crescent formation, and the combined values of U-Pod/Cr and U-PCX/Cr were shown to be associated with pure class V. Conclusions U-Pod/Cr and U-PCX/Cr correlate with histological features of lupus nephritis.

Clinical Study of α 2-MG, PCX, AFU, RBP-4 and CysC in type 2 Diabetes Mellitus and Diabetic Nephropathy

“…PCX is one of the speci c markers of PCX, so the presence of urine PCX only re ects speci c PCX barrier injury [23]. Previous studies have shown that elevated urinary PCX level can be used as a prediction of early renal damage in patients with early DN or lupus nephritis [24][25]. Our study also con rms the value of urine PCX in the diagnosis of early nephropathy.…”

Association between Renal Podocalyxin Expression and Renal Dysfunction in Patients with Diabetic Nephropathy: A Single-Center, Retrospective Case-Control Study

“…Another finding of this study was that urinary excretion of PCX increased as the renal expression of PCX decreased, which would be consistent with the detachment of PCX protein from renal tissue into the urine. Previous investigations determined that an increased PCX level in the urine could be used as a biomarker to predict early renal damage as well as the development and progression of complications in patients with early DN, anaphylactic purpura nephritis, lupus nephritis, or IgA nephropathy [15,[43][44][45][46][47]. In addition, BioMed Research International measuring PCX in urine is a noninvasive method that could be readily implemented in the clinical setting.…”

Distinct Functional Requirements for Podocalyxin in Immature and Mature Podocytes Reveal Mechanisms of Human Kidney Disease

“…With respect to a wider role for podocalyxin in kidney disease, it is noteworthy that soluble urinary PODXL has been consistently documented in patients with podocytopathies in a wide range of renal disorders. Indeed, this has been used as a biomarker of podocyte injury in lupus nephritis 31 , diabetic nephropathy 32,33 , obesity 34 , and hypertension 35 . Based on the data presented here, we would argue that urinary Podxl may not be merely a biomarker 20 .…”