title: Subattomole detection of adiponectin in urine by ultrasensitive ELISA coupled with thio-NAD cycling.
abstract: Adiponectin is a hormone secreted from adipocytes, and it demonstrates antidiabetic, anti-atherosclerotic, antiobesity and anti-inflammatory effects. However, the patterns of change in urinary adiponectin levels in various diseases remain unknown, because only trace amounts of the hormone are present in urine. In the present study, we applied an ultrasensitive ELISA coupled with thio-NAD cycling to measure urinary adiponectin levels. Spikeand-recovery tests using urine confirmed the reliability of our ultrasensitive ELISA. The limit of detection for adiponectin in urine was 2.3×10(-19) moles/assay (1.4 pg/mL). The urinary adiponectin concentration ranged between 0.04 and 5.82 ng/mL in healthy subjects. The pilot study showed that the urinary adiponectin levels, which were corrected by the creatinine concentration, were 0.73±0.50 (ng/mg creatinine, N=6) for healthy subjects, versus 12.02±3.85 (ng/mg creatinine, N=3) for patients with diabetes mellitus (DM). That is, the urinary adiponectin levels were higher (P<0.05) in DM patients than in healthy subjects. Further, these urinary adiponectin levels tended to increase with the progression of DM accompanied with nephropathy. Our method is thus expected to provide a simple, rapid and reasonably priced test for noninvasive monitoring of the progression of DM without the requirement of special tools.
authors: R&D Headquarters, TAUNS Laboratories, Inc., Shizuoka 410-2325, Japan; Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan.
authors: Mika
authors: M
authors: Morikawa
authors: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan.
authors: Rina
authors: R
authors: Naito
authors: Faculty of Science and Engineering, Tokushima Bunri University, Kagawa 769-2193, Japan.
authors: Koichi
authors: K
authors: Mita
authors: R&D Department, BL Co. Ltd., Shizuoka 410-0042, Japan.
authors: Satoshi
authors: S
authors: Watabe
authors: R&D Headquarters, TAUNS Laboratories, Inc., Shizuoka 410-2325, Japan.
authors: Kazunari
authors: K
authors: Nakaishi
authors: Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido 061-0293, Japan.
authors: Teruki
authors: T
authors: Yoshimura
authors: Graduate School of Pharmaceutical Sciences, Hokkaido University, Hokkaido 060-0812, Japan.
authors: Toshiaki
authors: T
authors: Miura
authors: Institute for Health Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan.
authors: Seiichi
authors: S
authors: Hashida
authors: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan.
authors: Etsuro
authors: E
authors: Ito
keywords: ELISA; adiponectin; diabetes; nephropathy; thio-NAD cycling; urine