Beta-endorphin levels in both painful and painless diabetic peripheral neuropathy and its relations to pain characters and severity

Abstract

Introduction. In the peripheral nervous system (PNS), beta-endorphins produce analgesia by binding to opioid receptors (particularly of the mu subtype) at both preand post-synaptic nerve terminals, primarily exerting their effect through presynaptic binding. Aim was to study serum beta-endorphin levels in diabetic patients with and without diabetic peripheral neuropathy and its relations to characters and severity of pain in patients with painful diabetic peripheral neuropathy. Material and methods. The study was a case control study including 88 participants; 73 diabetics and 15 age and sex matched healthy subjects. For all subjects, levels of HbA1c, serum creatinine, total cholesterol, triglycerides, HDL and LDL as well as serum levels of beta-endorphin were measured. Pain severity was detected by using visual analogue pain scale. Results. Serum beta-endorphin shows no significant difference between diabetic neuropathic, diabetic non neuropathic and control groups (p = 0.275). Serum beta-endorphin shows negative correlation with age (p = 0.049) and HbA1c (p = 0.048). While it was not correlated with pain severity (p = 0.371), NDS: total score (p = 0.803), BMI (p = 0.801), serum creatinine (p = 0.074) or DM duration (p = 0.607). Serum beta-endorphin shows no significant difference between painful and painless neuropathy subgroups (p = 0.701). Conclusion. In our study serum beta-endorphin levels showed no significant difference between patients with painless diabetic peripheral neuropathy and those with painful diabetic peripheral neuropathy with different characters of pain. Also, serum beta-endorphin levels was not correlated with pain severity.