[Pleiotropic action of proinsulin C-peptide]

Area of Science:

• Endocrinology
• Metabolic Research
• Neuroscience

Background:

• Proinsulin C-peptide was historically considered biologically inactive, primarily involved in insulin processing.
• Recent research over the past two decades suggests significant biological functions for C-peptide.
• The precise mechanism of C-peptide action, including its receptor, remains unidentified.

Purpose of the Study:

• To review the emerging evidence for C-peptide's biological functions.
• To explore C-peptide's therapeutic potential in ameliorating diabetes-related complications.
• To discuss controversies and future research directions for C-peptide.

Main Methods:

• Literature review of studies on C-peptide's biological activity and effects in diabetes.
• Analysis of in vitro and in vivo data regarding C-peptide's cellular and organ-level impacts.
• Examination of clinical observations and controversies surrounding C-peptide's role.

Main Results:

• C-peptide demonstrates protective effects against type 1 diabetes complications like glomerular hyperfiltration and neurodegeneration.
• It improves peripheral neuron function, promotes neuronal survival, and aids glycogen synthesis in skeletal muscles.
• In vitro, C-peptide aids insulin oligomer disaggregation, potentially enhancing insulin bioavailability.

Conclusions:

• C-peptide exhibits significant therapeutic potential for managing diabetes and its complications.
• Further large-scale clinical trials are necessary to confirm the safety and efficacy of C-peptide administration in diabetic patients.
• Controversies regarding C-peptide's effects, such as on Na⁺/K⁺-ATPase activity, require further investigation.