Assessment of neuron-specific enolase, glycated haemoglobin and fasting plasma glucose levels in patients with diabetes peripheral neuropathy in Calabar Metropolis, Nigeria: A case control study

Background: Persistent hyperglycemia has been implicated in the development of neuronal complications in diabetes patients. Nerve damage and metabolic abnormalities may cause the release of neuron specific enolase into circulation. Aim: To investigate the relationship between serum neuron-specific enolase (NSE), fasting plasma glucose (FPG) and glycated haemoglobin (HbA1C) levels in diabetic patients with peripheral neuropathy. Methods: one hundred and five patients with peripheral neuropathy and 60 apparently healthy non-diabetic controls aged 45-69 years attending Clinics in General Hospital Calabar and the University of Calabar Teaching Hospital, Calabar, between July 2021 and January 2022, were recruited into the study. Fasting plasma glucose was estimated using glucose oxidase peroxidase method. Glycated haemoglobin and NSE were determined using Boronate Affinity High Performance Liquid Chromatography and ELISA methods respectively. Height and weight were measured and BMI computed, and data analyzed using Student’s t-test, ANOVA, post hoc analysis and Pearson’s correlation at P<0.05. Results: Body mass index, blood pressure, fasting plasma glucose, glycated haemoglobin and neuron specific enolase concentrations were significantly different (P=<0.05) between the diabetic patients and the controls. Neuron specific enolase vary significantly (P<0.05) among the diabetic patients with different forms of diabetes peripheral neuropathy. Fasting plasma glucose correlated positively with NSE (r=0.441, P=0.000) and HbA1C (r=0.328, P=0.001) respectively. Glycated haemoglobin correlated positively with BMI (r=0.412, P=0.000) and NSE (r=0.328, P=0.001) in that order. Conclusion: This study has shown that glycated haemoglobin and fasting plasma glucose are related with neuron specific enolase levels in patients with diabetes peripheral neuropathy. Thus, rising levels of glycated haemoglobin and fasting plasma glucose (poor glycemic control) may be associated with progressive nerve damage in patients with diabetes peripheral neuropathy.