C-peptide protects against microvascular complications in Type 1 diabetes

Posted on October 22, 2009

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By Jenny Grice
20 February 2009
Diabetes Care 2009; 32: 301-305.

MedWire News: Study findings reveal that people with Type 1 diabetes and higher fasting C-peptide values have a lower prevalence of microvascular complications.

Type 1 diabetes is an autoimmune disorder in which the body’s immune system destroys the pancreatic islet beta-cells. C-peptide is secreted by beta cells and is an accepted marker of residual beta-cell function.

In a retrospective analysis, Francesco Panero (University of Turin, Italy) and co-workers determined whether residual beta-cell C-peptide secretion exerted a protective effect on diabetes-associated complications.

The authors recruited 471 people with Type 1 diabetes who were born in or after 1945 and who had been examined at least once during the period 1994–2004.

Clinical records were examined to determine whether patients’ had suffered any micro- and macrovascular complications. Patients were classified by C-peptide tertiles.

Reporting in the journal Diabetes Care, the authors observed residual beta-cell secretion even many years after diagnosis of Type 1 diabetes.

Fasting C-peptide values were positively correlated with age at diagnosis and triglycerides, and negatively with diabetes duration and high-density lipoprotein cholesterol.

The prevalence of complications was high particularly in patients with a longer diabetes duration. Ninety percent of patients with a duration of at least 30 years had one or more microvascular complications and 22% had one macrovascular complication.

“People with Type 1 diabetes and higher fasting C-peptide values had lower prevalence of microvascular complications independently of duration of diabetes,” write the authors.

Patients with C-peptide values of 0.06 nmol/l or more had a 41% lower prevalence of microvascular complications than patients with C-peptide values less than this.

The association was independent of individual cumulative haemoglobin A1c average suggesting that the effect could be directly due to the biological properties of C-peptide.

This association was not found with macrovascular complications.

“Prospective studies are needed to confirm the hypothesis that early therapeutic interventions aimed at preserving even small residual beta-cell secretion may modify the natural development of diabetes,” the authors conclude.

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