Renal hemodynamic changes and renal functional reserve in children with type I diabetes mellitus

Area of Science:

• Nephrology
• Pediatric Endocrinology
• Diabetology

Background:

• Increased glomerular filtration rate (GFR) is linked to diabetic nephropathy development.
• Significant normal variations in GFR complicate the diagnosis of renal hemodynamic alterations.
• Assessing renal functional reserve (RFR) may help identify early kidney changes in diabetic children.

Purpose of the Study:

• To evaluate RFR in children with type 1 diabetes mellitus.
• To determine if hyperfiltration occurs in normoalbuminuric diabetic children.
• To investigate renal hemodynamic responses to dopamine infusion in this population.

Main Methods:

• Examined renal hemodynamic response to dopamine infusion in 51 normoalbuminuric children with type 1 diabetes.
• Compared baseline GFR, renal plasma flow, and filtration fraction with 34 healthy controls.
• Measured mean RFR in both diabetic children and control subjects.

Main Results:

• Diabetic children had significantly lower renal plasma flow (463.7 vs. 587.2 ml/min per 1.73 m(2)) and increased filtration fraction (29% vs. 21%) compared to controls.
• Mean RFR was significantly lower in diabetic children (-0.77 ml/min per 1.73 m(2)) than in controls (21 ml/min per 1.73 m(2)).
• Baseline GFR did not differ between diabetic children and controls, indicating normal filtration rates initially.

Conclusions:

• Children with type 1 diabetes exhibit increased filtration fraction and reduced or absent RFR before overt nephropathy.
• These hemodynamic alterations suggest early kidney changes in diabetic children, despite normal GFR.
• The long-term relevance of reduced RFR and increased filtration fraction to hyperfiltration and diabetic nephropathy requires further investigation.