Objective: The aim of the study was to investigate whether serum lipopolysaccharide (LPS) activities are associated with the progression of kidney disease in patients with type 1 diabetes.
Research design and methods: For this prospective study, we chose 477 Finnish patients with type 1 diabetes, who were followed for 6 years. At the baseline visit, 239 patients had a normal albumin excretion rate (normoalbuminuria) and 238 patients had macroalbuminuria. Patients were further divided into nonprogressors and progressors based on their albumin excretion rate at follow-up. Eighty normoalbuminuric patients had developed microalbuminuria, and 79 macroalbuminuric patients had progressed to end-stage renal disease. Serum LPS activity was determined with the Limulus amoebocyte lysate chromogenic end point assay.
Results: Serum LPS activity was significantly higher in the macroalbuminuric group than in the normoalbuminuric group (P < 0.001). Notably, normoalbuminuric progressor patients had a significantly higher LPS activity at baseline than normoalbuminuric nonprogressor patients (median 49 [interquartile range 34-87] vs. 39 [29-54] EU/ml; P = 0.001). The normoalbuminuric progressor patients exhibited features of the metabolic syndrome with higher triglyceride concentrations and lower estimated glucose disposal rate. A high LPS-to-HDL ratio was associated with the progression of kidney disease in both groups. Insulin resistance (P < 0.001) and serum LPS activity (P = 0.026) were independent risk factors of disease development, when A1C was removed from the regression analysis.
Conclusions: High serum LPS activity is associated with the development of diabetic nephropathy in Finnish patients with type 1 diabetes.