Diabetology & Metabolic Syndrome (Aug 2024)

C-peptide: an essential ally in microvascular complications of type 2 diabetes mellitus and obesity

  • Regina Esze,
  • Sándor Barna,
  • Péter Fülöp,
  • Péter Kempler,
  • Márton Mikó,
  • Dénes Páll,
  • György Paragh,
  • Sándor Somodi,
  • Miklós Emri,
  • Zita Képes,
  • Ildikó Garai,
  • Miklós Káplár

DOI
https://doi.org/10.1186/s13098-024-01454-1
Journal volume & issue
Vol. 16, no. 1
pp. 1 – 11

Abstract

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Abstract Background In order to investigate microvascular complications in metabolic diseases, we aimed to investigate cerebral and peripheral microcirculation in relation to peripheral neuropathy and laboratory biomarkers in type 2 diabetes mellitus (T2DM) and obesity. Methods Based on the degree of neuropathy (NP), study participants (40 T2DM and 30 obese individuals) were classified into no-NP, mild-NP and severe-NP subgroups. After the injection of Technetium-99 m hexamethylpropylene amine oxime, both T2DM and obese participants underwent single-photon emission computed tomography/computed tomography ([99mTc]Tc-HMPAO SPECT/CT) and SPECT-only examinations to assess lower limb and brain perfusion; respectively. Peripheral nerve function was evaluated with a neurometer and glycaemic markers were measured from plasma in both groups. Results Compared to the obese individuals, lower extremity perfusion was significantly reduced in the diabetic subjects (p < 0.005), while it showed a positive correlation with C-peptide levels and negative association with HbA1c values. A U-shape pattern of peripheral microcirculation was observed between the NP groups, indicating a surprisingly better perfusion in the severe-NP group than in the mild one, with the highest levels in obese patients. Since changes in the C-peptide levels exhibited a similar U-shaped trend across the NP subgroups, we suggest a positive correlation between C-peptide levels and the extent of peripheral perfusion. Although, C-peptide values and cerebral microcirculation correlated positively (rho = 0.27), brain perfusion did not show any differences neither between the diabetic and the obese patients, nor between the NP subgroups (at p < 0.05). Conclusions Establishing the link between neuropathy and peripheral microcirculation, C-peptide seems to be a promising biomarker for the prediction of microvascular alterations in metabolic diseases. Of note, the dominance of metabolic factors over microvascular damage in the development of obesity-related neuropathy should be emphasized as well.

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