Decreased prorenin processing develops before autonomic dysfunction in type 1 diabetes

Area of Science:

• Endocrinology
• Nephrology
• Diabetology

Background:

• Diabetic patients with chronic complications exhibit reduced renin secretion and elevated prorenin.
• The cause of abnormal prorenin processing (microvascular disease, hypertension, or autonomic neuropathy) remains unclear.
• Previous studies suggested subclinical autonomic neuropathy in uncomplicated diabetes may cause prorenin processing abnormalities.

Purpose of the Study:

• To investigate the relationship between prorenin processing and autonomic function in early type 1 diabetes.
• To determine if abnormal prorenin processing precedes microvascular disease or autonomic dysfunction.
• To test the hypothesis that subclinical autonomic neuropathy causes abnormal prorenin processing in early diabetes.

Main Methods:

• Longitudinal study of 37 early type 1 diabetes patients and 41 age-matched controls over 3 years.
• Annual measurements of plasma renin activity (PRA), prorenin, and autonomic function tests.
• Analysis of renin-prorenin ratio and its correlation with autonomic function indices.

Main Results:

• Diabetic patients showed significantly lower PRA and renin-prorenin ratios compared to controls.
• No evidence of autonomic dysfunction or correlation with the renin-prorenin ratio in the first two evaluations.
• Significant correlations between the renin-prorenin ratio and heart rate variability power spectra (sympathetic modulation) were observed by the third evaluation.

Conclusions:

• Abnormal prorenin processing is an early feature of type 1 diabetes, preceding microvascular disease and overt autonomic dysfunction.
• While autonomic neuropathy may contribute, other unidentified mechanisms likely disrupt prorenin processing.
• Early detection of abnormal prorenin processing may offer insights into diabetes pathophysiology.