Detection of C-Peptide in Scalp Hair of Healthy Adults

Abstract

Purpose: The C-peptide level from blood and urine samples represents endogenous insulin secretion and has clinical implications for individuals with and without diabetes. However, the study results are inconsistent and the available methods can only measure short-term C-peptide levels, which can be substantially affected by concurrent glycaemia. In this study, we evaluated whether C-peptide can be detected from hair? Hair C-peptide if detected could potentially represent long-term, insulin secretion. And to know whether there is any correlation between hair C-peptide with certain biochemical and demographic parameters.

Methods: In a prospective observational study on 120 normal healthy individuals, hair samples were taken from the scalp and C-peptide was extracted. The hair C-peptide levels were measured in pg/mg of hair using electrochemiluminescence immunoassay (ECLISA) after methanol extraction and were compared among different age and body-type groups. Serum C-peptide, fasting plasma glucose (FPG) and HbA1c were assessed and their levels were correlated with anthropometric parameters.

Results: A detectable range of C-peptide was found in the hair samples of all the subjects with a median of 63.59 pg/mg hair and it was positively correlated with FPG but no significant correlation was found between hair C-peptide and serum C-peptide levels. The hair C-peptide level, along with FPG and HbA1c, was significantly different according to age.

Conclusion: These results conclude that C-peptide can be detected from and measured in the scalp hair of humans and it is positively correlated with FPG, and it is significantly different according to age. This technique, if validated, may verify its usefulness in future studies of both healthy and diseased subjects.

Keywords: C-peptide; fasting plasma glucose; hair sample; human.

Figure 1

Hair C-peptide level among male and female. The median of hair C-peptide level was compared using Mann–Whitney U-test. ^o mild outlier, * extreme outlier.

Figure 2

Hair C-peptide level among different age groups. The median of hair C-peptide level was compared between groups using Mann–Whitney U-test.

Figure 3

Hair C-peptide level among individuals with different BMIs. The median of hair C-peptide level was compared between groups using Mann–Whitney U-test. ^o mild outlier, * extreme outlier.

Figure 4

Relation of log hair C-peptide (A), serum C-peptide (B) and HbA1c (C) with the fasting plasma glucose (FPG). Pearson’s correlation was used to find the association between the means of the four variables.

Figure 5

A negative correlation between hair sample weight and the hair C-peptide levels. The correlation between the median of hair C-peptide and hair sample weight was used using Spearman correlation.