Abstract
Purpose :
Motilin receptor (MR) is a 22-amino-acid peptide G-protein-coupled membrane receptor that is known for its role in gastric motility. Recently, MR has been implicated in the proliferation of preadipocytes, differentiation of adipocytes, and the storage of lipids in adipocytes. We hypothesised that MR may be present in Meibomian glands. This study investigated the expression of motilin receptor in human eyelid tissue.
Methods :
Full thickness eyelid specimens in paraffin blocks from 2008 to 2011 were obtained from the Department of Anatomical Pathology at the Prince of Wales Hospital, Sydney, New South Wales, Australia. The specimens were originally excised for tumour management. A paraffin section from each block was stained with hematoxylin and eosin and examined by an ocular pathologist for validation of tissue pathology. Immunohistochemistry was performed using rabbit polyclonal anti-MR antibody on serial paraffin sections from each block. Positive and negative controls of small intestine were included.
Results :
Thirteen full thickness eyelid specimens were included in this study. The mean age at the time of surgical excision was 70 years (range 43.0 to 95.9, standard deviation 15.3). The histopathological diagnoses were basal cell carcinoma in 11 (84.6%) and sebaceous cell carcinoma in 2 (15.4%) specimens. All specimens contained meibomian glands, 3 (23.1%) contained glands of Zeiss, 4 (30.8%) contained sebaceous glands, 7 (53.8%) contained glands of Moll, 10 (76.9%) contained eccrine sweat glands, and 2 (15.4%) contained accessory lacrimal glands. The anti-human MR antibody positively stained the accessory lacrimal glands in 2 different specimens. Accessory lacrimal glands were not present in the sections of the 11 other specimens examined. Motilin immunostaining of other glandular structures or tissues was not seen.
Conclusions :
Motilin receptors were expressed only in the accessory lacrimal glands of the human eyelid. Further studies are needed to confirm the functional activity and role of MR in the eyelids.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.