Salivary opiorphin levels in anorexia nervosa: A case–control study

Abstract

Objectives: Opiorphin is a physiological inhibitor of peptidases inactivating endogenous opioids displaying strong analgesic properties without undesirable side effects, antidepressant properties or hormonal dependency. It might therefore play an important role in patients with painful diseases related to neuro-hormonal dysregulation of the nervous system, affecting saliva secretion and composition such as anorexia nervosa (AN). The main objective aim of this study was to compare the level of opiorphin in saliva of patients with AN to matched subjects free of eating disorders.

Methods: A case–control clinical trial was conducted in 68 AN patients and 43 healthy matched control subjects. Depression symptoms were assessed with the self-scored questionnaire Beck Depression Inventory (BDI) and salivary samples were taken during the acute stage of AN (BMI <15 kg/m²) for measuring opiorphin. Opiorphin levels were measured with a quantitative assay using a commercial immunoenzymatic Elisa kit (cat no. EH1927, Wuchan, Hubei, China).

Results: No statistically significant difference was found in salivary opiorphin levels between the AN and control groups, (P = 0.499, Mann–Whitney U-test). Positive correlations to duration of the disease, BDI and bodyweight in AN patients were evidenced.

Conclusions: Measurement of salivary opiorphin levels cannot be used as a marker of AN but may allow new perspectives in monitoring AN in its early stages.

Keywords:

• Eating disorders
• anorexia nervosa
• opiorphin
• saliva
• depression symptoms

Acknowledgments

The authors would like to thank all those who participated in this study for their enthusiastic involvement and hard work. The authors would like to thank the Poznan University of Medical Sciences for supporting the study. We gratefully acknowledge the assistance of dr Richard Reisner for his advice concerning English language editing. The funders had no role in study design, data collection and analysis, the decision to publish, or the preparation of this manuscript.

Ethical approval

This article does not contain any studies with animals performed by any of the authors. All procedures involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Statement of interest

Elzbieta Paszynska declares that she has no conflict of interest. Monika Dmitrzak-Weglarz declares that she has no conflict of interest. Magdalena Roszak declares that she has no conflict of interest. Yves Boucher declares that she has no conflict of interest. Agata Dutkiewicz declares that she has no conflict of interest. Maria Gawriolek declares that she has no conflict of interest. Justyna Otulakowska-Skrzynska declares that she has no conflict of interest. Szymon Rzatowski declares that she has no conflict of interest. Marta Tyszkiewicz-Nwafor declares that she has no conflict of interest. Agnieszka Slopien declares that she has no conflict of interest.

Additional information

Funding

The work was supported by Poznan University of Medical Sciences. Financial source from PUMS.