Capillary permeability is increased in normo- and microalbuminuric Type I diabetic patients: amelioration by ACE-inhibition

Background Capillary leakage of sodium-fluorescein (NaF) in the skin reflects capillary permeability and may be a marker of diabetes-associated microcirculatory abnormalities.

Design We evaluated transcapillary skin NaF leakage by fluorescence videodensitometry in 10 normoalbuminuric, 10 microalbuminuric Type I diabetic men (diabetes duration > 10 years) and 10 healthy subjects. The microalbuminuric patients were restudied after 6 weeks treatment with the ACE-inhibitor enalapril, 10 mg once daily. All measurements were performed at a blood glucose level of 5 mmolL(-1) .

Results Transcapillary NaF leakage was strongly increased in normoalbuminuric Type 1 diabetic patients compared to healthy subjects (P <0.001) and was still further increased in microalbuminuric Type 1 diabetic patients (P <0.01 compared to normoalbuminuric patients). Enalapril reduced NaF leakage (p <0.05), mean arterial blood pressure (P <0.05) and microalbuminuria (P <0.05). After treatment, NaF leakage was not different from that in normoalbuminuric patients.

Conclusions Capillary permeability, as determined by NaF leakage, is elevated in normoalbuminuric Type 1 diabetic patients with long-standing disease, and the excess elevation in microalbuminuric Type 1 diabetic patients is ameliorated by ACE-inhibition. Skin NaF videodensitometry seems a useful tool to document capillary permeability in intervention studies.