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Published on: July 18, 2016
Preoperative concentration of beta-lipotropin immunoreactive material in cerebrospinal fluid: a predictor of
Reginald Matejec1, Axel Schulz, Jörg Mühling
1Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Justus-Liebig-University, Rudolf-Buchheim-Str. 7, D-35392 Giessen, Germany. reginald.matejec@chiru.med.uni-giessen.de
Abstract:
Levels of beta-endorphin immunoreactive material (IRM) in cerebrospinal fluid (CSF) have been reported to correlate inversely with postoperative morphine requirement. Considering proopiomelanocortin (POMC) derivatives as predictors for sensitivity to postoperative pain, we determined authentic beta-endorphin (beta-endorphin(1-31)), beta-lipotropin IRM, N-acetyl-beta-endorphin IRM and ACTH in CSF of 17 patients undergoing hip or knee arthroplasty, before surgery (t(A)), immediately after termination of propofol infusion and still under spinal anesthesia (t(B)), under postoperative pain (t(C)) and one day after surgery (t(D)); patients rated their severity of pain on a visual analogue scale (VAS) at those four times. In all patients CSF concentrations of N-acetyl-beta-endorphin IRM and beta-lipotropin IRM were found to be increased after terminating the propofol infusion with spinal anesthesia still effective at t(B). Patients did not feel pain at times t(A), t(B) or t(D); however, they reported moderate to considerable pain at t(C). There were no correlations of postoperative pain severity at t(C) with ACTH, beta-endorphin(1-31) or N-acetyl-beta-endorphin IRM concentrations in CSF. In contrast, we observed significant inverse correlations (Spearman's rank correlation coefficients between -0.83 and -0.85, p<0.01) for postoperative pain severity with beta-lipotropin IRM concentrations in CSF at t(C), and, in addition, at t(A), t(B) and t(D); thus, postoperative pain severity appeared to be dependent on a central system controlling sensitivity to pain, linked to a POMC system releasing beta-lipotropin IRM into CSF and already active at times t(A) and t(B). We conclude that beta-lipotropin IRM in CSF might be considered to serve as a predictor of sensitivity to postoperative pain.
Insights
Cerebrospinal fluid beta-lipotropin levels may predict postoperative pain sensitivity. Lower beta-lipotropin immunoreactive material (IRM) in CSF correlated with increased pain, suggesting a central pain sensitivity system linked to proopiomelanocortin (POMC) derivatives.
Area of Science:
- Neuroscience
- Pain Management
- Endocrinology
Background:
- Proopiomelanocortin (POMC) derivatives in cerebrospinal fluid (CSF) may indicate sensitivity to postoperative pain.
- Previous studies suggest an inverse correlation between beta-endorphin levels and postoperative morphine requirements.
Purpose of the Study:
- To investigate the relationship between specific POMC derivatives in CSF and postoperative pain severity.
- To determine if beta-lipotropin immunoreactive material (IRM) can serve as a predictor of pain sensitivity.
Main Methods:
- CSF samples were collected from 17 patients undergoing hip or knee arthroplasty at four time points: pre-surgery, post-propofol/spinal anesthesia, during postoperative pain, and one day post-surgery.
- Patients rated pain severity using a visual analogue scale (VAS).
- CSF concentrations of beta-endorphin(1-31), beta-lipotropin IRM, N-acetyl-beta-endorphin IRM, and ACTH were measured.
Main Results:
- CSF concentrations of N-acetyl-beta-endorphin IRM and beta-lipotropin IRM increased after propofol infusion termination while spinal anesthesia was still effective.
- No significant correlations were found between postoperative pain severity and CSF ACTH, beta-endorphin(1-31), or N-acetyl-beta-endorphin IRM.
- Significant inverse correlations were observed between postoperative pain severity and CSF beta-lipotropin IRM concentrations at all measured time points.
Conclusions:
- Postoperative pain severity appears to be linked to a central pain sensitivity system involving the POMC system and beta-lipotropin IRM release into CSF.
- CSF beta-lipotropin IRM may serve as a valuable predictor for individual sensitivity to postoperative pain.
