Zinc-α2-glycoprotein is associated with non-albuminuric chronic kidney disease progression in type 2 diabetes: a retrospective study with 4-year follow-up

Serum Zinc-α2-glycoprotein Levels Are Associated with the Hepatorenal Function and Predict the Survival in Cases of Chronic Liver Disease

Objective Zinc-α2-glycoprotein (ZAG) is secreted by various organs, such as liver, kidney and adipose tissue, is involved in lipolysis, and may contribute to the pathogenesis of chronic liver disease (CLD). We therefore assessed whether or not ZAG is a surrogate marker for the hepatorenal function, body composition and all causes of mortality, as well as complications, including ascites, hepatic encephalopathy (HE) and portosystemic shunts (PSS) in CLD. Methods Serum ZAG levels were measured in 180 CLD patients upon hospital admission. The associations of ZAG levels with the liver functional reserve and clinical parameters were investigated using a multiple regression analysis. Kaplan-Meier analyses were performed to evaluate the associations of the ZAG/creatinine ratio (ZAG/Cr) and prognostic factors with mortality. Results High serum ZAG levels were associated with preserving the liver function and renal insufficiency. A multiple regression analysis showed that the estimated glomerular filtration rate (p<0.0001), albumin-bilirubin (ALBI) score (p=0.0018) and subcutaneous fat area (p=0.0023) had a significant independent correlation with serum ZAG levels. Serum ZAG levels were elevated in the absence of HE (p=0.0023) and PSS (p=0.0003). In all patients and those without hepatocellular carcinoma (HCC), the cumulative mortality rate was significantly decreased in patients with a high ZAG/Cr compared with those with a low ZAG/Cr (p=0.0018 and p=0.0002, respectively). The ZAG/Cr, presence of HCC, ALBI score and psoas muscle index were independent predictors of the prognosis in CLD patients. Conclusion Serum ZAG levels are associated with the hepatorenal function and can be used to predict the survival in CLD patients.

Association of inflammation-related markers and diabetic retinopathy severity in the aqueous humor, but not serum of type 2 diabetic patients

Diabetic retinopathy (DR) is a frequent microvascular complication of diabetes mellitus, and inflammatory pathways have been linked to its pathogenesis. In this retrospective, observational pilot study, we aimed to compare the concentrations of four inflammation-related proteins, ZAG, Reg-3a, elafin and RBP-4, in the serum and aqueous humor of healthy controls and diabetic patients with different stages of DR. The concentrations of VEGF-A, IL-8, IL-6 were determined in parallel as internal controls. In the serum, we did not find significant differences in the concentrations of target proteins. In the aqueous humor, higher levels of ZAG, RBP-4, Reg-3a and elafin were observed in advanced nonproliferative DR (NPDR)/ proliferative DR (PDR) compared to controls. The levels of ZAG and RBP-4 were also higher in advanced NPDR/PDR than in nonapparent DR. Normalization of target protein concentrations to the aqueous humor total protein demonstrates that a spill-over from serum due to breakage of the blood-retina barrier only partially accounts for increased inflammation related markers in later stages. In conclusion, we found elevated levels of Reg-3a, RBP-4, elafin and ZAG in advanced stages of diabetic retinopathy. Higher levels of pro-inflammatory proteins, Reg-3a and RBP-4, might contribute to the pathogenesis of diabetic retinopathy, as the parallel increased concentrations of anti-inflammatory molecules elafin and ZAG might indicate a compensatory mechanism.