Cysteinylated Albumin as a Potential Biomarker for the Progression of Kidney Disease in Patients With Type 2 Diabetes.

Currently, the gold standard for diagnosing diabetic kidney disease (DKD) is the measurement of the urinary albumin-to-creatinine ratio (UACR), but it has been clarified that there are many cases of decreased renal function and atypical nephropathy without the development of albuminuria (1,2). Given these diversified pathologies of DKD, it is necessary to identify new biomarkers that can predict renal prognosis at an earlier disease stage. In this retrospective case-control study, we performed posttranslational modification analysis of plasma albumin by electrospray ionization time-of-flight mass spectrometry (3,4) in 257 outpatients with type 2 diabetes at a single center to evaluate association between the posttranslational modifications of albumin and DKD progression. In fact, 257 patients with type 2 diabetes (179 men and 78 women) aged 49–80 years (mean ± SD 67.1 ± 10.7) who visited the Jinnouchi Clinic, Diabetes Care Center, in Kumamoto, Japan, between April 2014 and June 2017 were enrolled, and the follow-up period was 2 years. According to Kidney Disease: Improving Global Outcomes (KDIGO) glomerular filtration rate (GFR) categories in chronic kidney disease, the subjects were classified into five estimated (e)GFR stages (Fig. 1 A ). Figure 1 A : Characteristics of patients enrolled in this study ( n = 257; 179 men, 78 women). B : The mass peaks of each posttranslational form of serum albumin in patients with type 2 diabetes. C and …