CGRP measurements in human plasma – a methodological study. (November 2021)

• Record Type: Journal Article
• Authors: Messlinger, Karl; Vogler, Birgit; Kuhn, Annette; Sertel-Nakajima, Julika; Frank, Florian; Broessner, Gregor
• Is Part Of: Cephalalgia. Volume 41:Number 13(2021)
• Page Start: 1359
• Page End: 1373
• Publication Date: 2021-11
• Subjects: Calcitonin gene-related peptide -- enzyme-linked immunosorbent assay -- blood plasma -- normobaric hypoxia; Headache -- Periodicals; 616.8491
• DOI: 10.1177/03331024211024161
• Languages: English
• ISSNs: 0333-1024

Abstract

Background: Calcitonin gene-related peptide plasma levels have frequently been determined as a biomarker for primary headaches. However, published data is often inconsistent resulting from different methods that are not precisely described in most studies. Methods: We applied a well-proven enzyme-linked immunosorbent assay to measure calcitonin gene-related peptide concentrations in human blood plasma, we modified parameters of plasma preparation and protein purification and used calcitonin gene-related peptide-free plasma for standard solutions, which are described in detail. Results: Calcitonin gene-related peptide levels are stable in plasma with peptidase inhibitors and after deep-freezing. Calcitonin gene-related peptide standard solutions based on synthetic intercellular fluid or pooled plasma with pre-absorbed calcitonin gene-related peptide influenced the measurements but yielded both comprehensible results. In a sample of 56 healthy subjects the calcitonin gene-related peptide plasma levels varied considerably from low (<50 pg/mL) to very high (>500 pg/mL) values. After a 12-hour exposure of these subjects to normobaric hypoxia the individual calcitonin gene-related peptide levels remained stable. Conclusion: Buffering with peptidase inhibitors and immediate freezing or processing of plasma samples is essential to achieve reliable measurements. Individuals show considerable differences and partly high calcitonin gene-related peptide plasma levels without detectable pathological reason. Thus plasma measurements are suited particularly to follow calcitonin gene-related peptide levels in longitudinal studies. The use of data for this study was approved by the Ethics Committee of the Medical University of Innsbruck (https://www.i-med.ac.at/ethikkommission/ ; EK Nr: 1242/2017).