Development of fully automated and ultrasensitive assays for urinary adiponectin and their application as novel biomarkers for diabetic kidney disease

Toshihiro Watanabe,Motohiro Aiba,Mai Nishiyama,Akinori Kawai,Seiichi Hashida,Hiroyasu Mori,Munehide Matsuhisa,Seiki Okada,Masashi Ishizu,Yuki Fujimoto,Makoto Funaki,Tomoharu Kawano,Akiko Hata,Mina Kawahigashi,Aya Morimoto

doi:10.1038/s41598-020-72494-6

Abstract

Glomerular filtration rate (GFR) and urinary albumin excretion rate (UAER) are used to diagnose and classify the severity of chronic kidney disease. Total adiponectin (T-AN) and high molecular weight adiponectin (H-AN) assays were developed using the fully automated immunoassay system, HI-1000 and their significance over conventional biomarkers were investigated. The T-AN and H-AN assays had high reproducibility, good linearity, and sufficient sensitivity to detect trace amounts of adiponectin in the urine. Urine samples after gel filtration were analyzed for the presence of different molecular isoforms. Low molecular weight (LMW) forms and monomers were the major components (93%) of adiponectin in the urine from a diabetic patient with normoalbuminuria. Urine from a microalbuminuria patient contained both high molecular weight (HMW) (11%) and middle molecular weight (MMW) (28%) adiponectin, although the LMW level was still high (52%). The amount of HMW (32%) and MMW (42%) were more abundant than that of LMW (24%) in a diabetic patient with macroalbuminuria. T-AN (r = − 0.43) and H-AN (r = − 0.38) levels showed higher correlation with estimated GFR (eGFR) than UAER (r = − 0.23). Urinary levels of both T-AN and H-AN negatively correlated with renal function in diabetic patients and they may serve as new biomarkers for diabetic kidney disease.

Highlights

Glomerular filtration rate (GFR) and urinary albumin excretion rate (UAER) are used to diagnose and classify the severity of chronic kidney disease
Similar to our previous study, in which Total adiponectin (T-AN) assays were conducted m anually[29, 4] peaks, which correspond to high molecular weight (HMW), middle molecular weight (MMW), Low molecular weight (LMW) and monomeric adiponectin, respectively, were observed by the T-AN assay
The high molecular weight adiponectin (H-AN) assay generated a single peak that corresponded to HMW adiponectin, a weak signal without a peak was detected in fractions corresponding to MMW adiponectin

Summary

Introduction

Glomerular filtration rate (GFR) and urinary albumin excretion rate (UAER) are used to diagnose and classify the severity of chronic kidney disease. T-AN (r = − 0.43) and H-AN (r = − 0.38) levels showed higher correlation with estimated GFR (eGFR) than UAER (r = − 0.23) Urinary levels of both T-AN and H-AN negatively correlated with renal function in diabetic patients and they may serve as new biomarkers for diabetic kidney disease. Glomerular filtration rate (GFR) and urinary albumin excretion rate (UAER) have been used to diagnose and classify the severity of C KD3, and previous studies have shown that urinary adiponectin may be useful as a biomarker of CKD, as well. Using antibody-coated magnetic particles to increase capture efficiency, immune complex transfer enables interfering background signal to be eliminated, thereby enhancing analytical sensitivity

Methods

Results

Conclusion