C-peptide improves autonomic nerve function in IDDM patients

Abstract

In order to determine the possible influence of C-peptide on nerve function, 12 insulin-dependent diabetic (IDDM) patients with symptoms of diabetic polyneuropathy were studied twice under euglycaemic conditions. Tests of autonomic nerve function (respiratory heart rate variability, acceleration and brake index during tilting), quantitative sensory threshold determinations, nerve conduction studies and clinical neurological examination were carried out before and during a 3-h i.v. infusion of either C-peptide (6 pmol.kg-1.min-1) or physiological saline solution in a double-blind study. Plasma C-peptide concentrations increased from 0.11 +/- 0.02 to 1.73 +/- 0.04 nmol/l during C-peptide infusion. Clinical neurological examination quantitative sensory threshold evaluations and nerve conduction measurements failed to detect significant changes between C-peptide and saline study periods. Respiratory heart rate variability increased significantly from 13 +/- 1 to 20 +/- 2% during C-peptide infusion (p < 0.001), reaching normal values in five of the subjects; control studies with saline infusion did not alter the heart rate variability (basal, 14 +/- 2; saline, 15 +/- 2%). A reduced brake index value was found in seven patients and increased significantly during the C-peptide infusion period (4.6 +/- 1.0 to 10.3 +/- 2.2%, p < 0.05) but not during saline infusion (5.9 +/- 2 to 4.1 +/- 1.1%, NS). It is concluded that short-term (3-h) infusion of C-peptide in physiological amounts may improve autonomic nerve function in patients with IDDM.

Unordered structure of proinsulin C-peptide in aqueous solution and in the presence of lipid vesicles

“…Renewed interest in C-peptide was prompted by the finding that C-peptide may prevent or retard the development of microvascular complications in insulin-dependent diabetes mellitus (IDDM) patients [1]. Thus, C-peptide has been found to improve renal function [2,3], stimulate glucose transport in skeletal muscle [4,5], increase skeletal muscle blood flow and oxygen uptake [4,6], and improve autonomic and motor nerve function [7,8] in IDDM patients and in animals with experimental diabetes. The mechanism(s) behind these physiological effects are not fully known.…”

C-peptide prevents and improves chronic Type I diabetic polyneuropathy in the BB/Wor rat

“…Short time studies have reported beneficial effects of C-peptide on renal, sensory and autonomic abnormalities in Type I diabetic patients [19,20].…”

Acute effects of C-peptide on gastric emptying in longstanding type 1 diabetes

“…In contrast, patients with type 2 diabetes, characterized by insulin resistance, often have normal or elevated C-peptide concentrations [7]. There is evidence that C-peptide may improve autonomic function in type 1 diabetes [14,15,23,27]. Our aim was to evaluate the acute effects of C-peptide on gastric emptying in patients with longstanding type 1 diabetes.…”