Tezenas du Montcel C, Duriez P, Lebrun N, Grouselle D, de Grimaudet B, Dardennes R, Epelbaum J, Cuenca M, Viltart O, Gorwood P, Tolle V. Methodological considerations for ghrelin isoforms assay in clinical evaluation in anorexia nervosa.
COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2022;
11:100140. [PMID:
35757178 PMCID:
PMC9227986 DOI:
10.1016/j.cpnec.2022.100140]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 11/29/2022] Open
Abstract
The growing interest concerning the role of metabolic sensors in various eating disorders requires the implementation of a strict methodology to collect, store and process blood samples in clinical studies. In particular, measurement of isoforms of the appetite-stimulating hormone, ghrelin, has been challenging in clinical settings. Indeed the acyl ghrelin (AG) isoform is rapidly degraded into desacyl ghrelin (DAG) by blood esterases, thus optimal conditions for the conservation of AG and accurate determination of AG/DAG ratio should be used. Here, we compared different protease inhibitors (Aprotinin, PHMB, AEBSF) during blood collection, increasing delays (0–180 min) before centrifugation, plasma supplementation with various HCl concentrations, storage durations of frozen plasma (8 and 447 days) and immunoenzyme-assay procedures (one-step versus sequential) in healthy subjects. Optimal conditions were obtained by collecting blood with aprotinin and supplementation of plasma with 0.1 N HCl with subsequent freezing for at least 8 days and using one-step assay. Under such conditions, different patterns of secretion of ghrelin isoforms were characterized in patients with restrictive-type anorexia nervosa (AN-R) before and after nutritional recovery. We illustrate the pulsatile variations of ghrelin isoforms according to the time around a meal and hunger rates in 3 patients with AN-R. This study offers a comprehensive comparison of various conditions using selective and specific immunoassays for both ghrelin isoforms in order to optimize assay sensitivity and consistency among procedures. These assay conditions could therefore be widely used to elucidate precisely the role of ghrelin isoforms on eating behavior in physiological and pathological situations.
Treatment conditions and assay procedures are critical for ghrelin isoforms level determination in plasma.
Specific treatment conditions allow long term stability of ghrelin isoforms.
HCl supplementation of plasma before freezing improves AG/DAG ratio on the short and long term.
Variations of ghrelin isoforms occur with meal timing and chronic nutritional status in patients with anorexia nervosa.
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