Motilin Receptor Expression Found in the Human Main and Accessory Lacrimal Glands

ABSTRACT

Introduction

In this study, we investigated the presence of motilin receptors (MR) in adnexal tissue including the human main lacrimal gland.

Method

17 adnexal human specimens comprising of 11 isolated human main lacrimal gland specimens, four full-thickness human eyelid excisions and two exenterations containing full-thickness eyelid and portions of the main lacrimal gland were immunolabelled with a rabbit polyclonal human MR antibody.

Results

Our results demonstrated that all main lacrimal gland specimens (13/13, 100%) were positive for MR expression with a predominance (10/13 (77%) of grade 1+ punctate distribution. Motilin receptors were not found in eccrine glands, cutaneous sebaceous glands, glands of Zeis or glands of Moll (0/6, 0%). We also confirmed MR expression in the accessory lacrimal gland tissue.

Conclusion

In summary, we discovered the MR receptor in the lacrimal and accessory lacrimal gland - the significance of which, in the lacrimal gland, remains unclear - but motilin may play a role in the muscarinic control of aqueous tear secretion.

KEYWORDS:

• Motilin
• lacrimal gland
• immunohistochemistry
• accessory lacrimal
• meibomian gland

Acknowledgments

Pathologists/Laboratory staff at Douglas Hanly Moir for assistance with immunochemistry and microscopy and providing adnexal tissue specimens.

Authors’ contributions

Dr Richard Sadig – Literature review; manuscript writing; co-examination of slides; draft editing; submission. Dr Alexandra Allende, Dr Geoffrey Hall – Specimen selection; immunochemistry and microscopy grading; draft editing. Mr Dinh Tran – Immunochemistry

Assoc. Prof. Michele Madigan – Laboratory assistance; manuscript writing and editing.

Prof. Stephanie Watson & Dr Kenneth Ooi – Principal investigators/supervisors; conceptualization; served as scientific advisors; critically reviewed the study proposal; manuscript editing.

Consent to participate

This is a retrospective study involving human formalin-fixed paraffin embedded tissue samples with a waiver for informed consent obtained and overseen by the Northern Sydney Local Health District, consistent with the principles of the Declaration of Helsinki.

Consent for publication

Deidentified archival tissue used with waiver for informed consent applied. Overseen by the Northern Sydney Local Health District and consistent with the principles of the Declaration of Helsinki.

Declaration of interest

The authors declare no competing or conflicting interests.

Ethics approval

Approval was obtained from Douglass Hanly Moir Pathology Park Laboratory, with ethics review overseen by Northern Sydney Local Health District consistent with the principles of the Declaration of Helsinki.

Additional information

Funding

Save Sight Institute, University of Sydney, 8 Macquarie St, Sydney NSW 2000 Australia. S Watson is a Sydney Medical School Foundation fellow.