Presentation of Meibomian Acini Compared to Dermal Papillae of the Eyelid Margin, Using Confocal Laser Scanning Microscopy and Corresponding Histology

Abstract

Background Numerous studies have investigated the eyelid margin using confocal laser scanning microscopy (CLSM) and have presented morphological alterations of the examined structures, which were presumed to be Meibomian acini. However, recent data confirm that these structures are the cross-sections of dermal papillae of the dermoepidermal junction. This study aims to present the morphological appearance of Meibomian acini examined by confocal laser scanning microscopy in comparison to dermal papillae, and to reveal the corresponding patterns with specific histological sections.

Methods and Material Twenty healthy patients were examined with a CLSM device in vivo at the marginal edge of the eyelid. Twenty-two samples of full-thickness eyelid wedges from 22 patients treated surgically with ectropion were collected, of which 11 freshly excised samples were imaged on the incision surface with CLSM ex vivo and 11 eyelids underwent conventional histological preparation. The represented structures on CLSM images were compared to Meibomian acini on histological sections in terms of area, longest and shortest diameter, as well as depth and density.

Results On in vivo CLSM images, Meibomian orifices, epidermal cells, and dermal connective tissue could be identified, the latter in a cross-sectional view of the dermal papillae surrounded by basal cells of the epidermis, forming reflective ring-like structures. All morphological parameters of these structures differed from Meibomian acini measured on histological sections. In contrast, the CLSM images of the incision surface showed acinar units with the same morphology as the Meibomian acini seen in the histological images and no statistically significant difference was found between the corresponding parameters.

Conclusion The morphological appearance of Meibomian acini differs from the structures that were previously presumed as Meibomian glands on CLSM images. In vivo imaging of Meibomian glands by commonly used in vivo CLSM cannot be performed.

Zusammenfassung

Hintergrund Zahlreiche Studien haben den Lidrand mittels konfokaler Laser-Scanning-Mikroskopie (CLSM) untersucht und gewisse morphologischen Veränderungen der untersuchten Strukturen gezeigt, die als vermutliche Meibom-Azini angesprochen wurden. Neueste Daten jedoch bestätigen, dass diese Strukturen Querschnitte von dermalen Papillen der dermoepidermalen Verbindungen sind. Ziel dieser Studie ist es, die Morphologie von Meibom-Azini, die mit konfokaler Laser-Scanning-Mikroskopie untersucht wurden, im Vergleich zu dermalen Papillen darzustellen und die entsprechenden Muster mit spezifischen histologischen Schnitten aufzuzeigen.

Material und Methoden 20 gesunde Patienten wurden mit dem CLS-Mikroskop in vivo am Augenlidrand untersucht. Des Weiteren wurden 22 Proben von Lidkeilen in voller Dicke von 22 Patienten gesammelt, die aufgrund von Ektropium chirurgisch behandelt wurden, 11 frisch entnommene Proben davon wurden auf der Schnittoberfläche mit CLSM ex vivo untersucht, die anderen 11 Augenlidproben wurden nach herkömmlicher Präparation histologisch untersucht. Die auf CLSM-Bildern dargestellten Strukturen wurden hinsichtlich der Fläche, dem längsten und kürzesten Durchmesser sowie der Tiefe und Dichte mit Meibom-Azini auf histologischen Schnitten verglichen.

Ergebnisse Auf In-vivo-CLSM-Bildern konnten Meibom-Öffnungen, Epidermiszellen und dermales Bindegewebe festgestellt werden, letzteres in einem Querschnitt der Hautpapillen, die von Basalzellen der Epidermis umgeben sind und reflektierende ringartige Strukturen bilden. Alle morphologischen Eigenschaften dieser Strukturen unterschieden sich von den an histologischen Schnitten untersuchten Meibom-Azini. Im Gegensatz dazu zeigten die CLSM-Bilder der Schnittoberfläche Azinuseinheiten mit derselben Morphologie wie die Meibom-Azini in den histologischen Bildern, im Vergleich der entsprechenden Parameter ohne einen signifikanten statistischen Unterschied.

Schlussfolgerung Das morphologische Erscheinungsbild der Meibom-Azini unterscheidet sich von den Strukturen, die zuvor auf CLSM-Bildern als Meibom-Drüsen vermutet wurden. Eine In-vivo-Darstellung von Meibom-Drüsen mittels herkömmlichen In-vivo-CLSM kann bis heute nicht durchgeführt werden.

Keywords

Meibomian glands - confocal laser scanning microscopy - dermal papillae - dermoepidermal junction - eyelid

Schlüsselwörter

Meibom-Drüsen - konfokale Laser-Scanning-Mikroskopie - dermale Papillen - dermoepidermaler Übergang - Augenlid

• References

• 1 Stachs O, Guthoff RF, Aumann S. Atlas of Confocal Laser Scanning in-vivo Microscopy in Ophthalmology. Berlin: Springer; 2016
• 2 Dirckx JJ, Kuypers LC, Decraemer WF. Refractive index of tissue measured with confocal microscopy. J Biomed Opt 2005; 10: 44014
• 3 Petroll WM, Robertson DM. In Vivo Confocal Microscopy of the Cornea: New Developments in Image Acquisition, Reconstruction, and Analysis Using the HRT-Rostock Corneal Module. Ocul Surf 2015; 13: 187-203
• 4 Kobayashi A, Yoshita T, Sugiyama K. In vivo findings of the bulbar/palpebral conjunctiva and presumed meibomian glands by laser scanning confocal microscopy. Cornea 2005; 24: 985-988
• 5 Randon M, Aragno V, Abbas R. et al. In vivo confocal microscopy classification in the diagnosis of meibomian gland dysfunction. Eye (Lond) 2019; 33: 754-760
• 6 Wei Q, Le Q, Hong J. et al. In vivo confocal microscopy of meibomian glands and palpebral conjunctiva in vernal keratoconjunctivitis. Indian J Ophthalmol 2015; 63: 327-330
• 7 Mastropasqua L, Agnifili L, Mastropasqua R. et al. In vivo laser scanning confocal microscopy of the ocular surface in glaucoma. Microsc Microanal 2014; 20: 879-894
• 8 Villani E, Ceresara G, Beretta S. et al. In vivo confocal microscopy of meibomian glands in contact lens wearers. Invest Ophthalmol Vis Sci 2011; 52: 5215-5219
• 9 Villani E, Canton V, Magnani F. et al. The aging Meibomian gland: an in vivo confocal study. Invest Ophthalmol Vis Sci 2013; 54: 4735-4740
• 10 Zhou S, Robertson DM. Wide-Field In Vivo Confocal Microscopy of Meibomian Gland Acini and Rete Ridges in the Eyelid Margin. Invest Ophthalmol Vis Sci 2018; 59: 4249-4257
• 11 Obata H. Anatomy and histopathology of human meibomian gland. Cornea 2002; 21: S70-S74
• 12 Jue MS, Yoo J, Kim MS. et al. The Lateral Tarsal Strip for Paralytic Ectropion in Patients with Leprosy. Ann Dermatol 2017; 29: 742-746
• 13 Sadeghipour A, Babaheidarian P. Making Formalin-Fixed, Paraffin Embedded Blocks. Methods Mol Biol 2019; 1897: 253-268
• 14 Ibrahim OM, Matsumoto Y, Dogru M. et al. In vivo confocal microscopy evaluation of meibomian gland dysfunction in atopic-keratoconjunctivitis patients. Ophthalmology 2012; 119: 1961-1968
• 15 Knop E, Knop N, Millar T. et al. The international workshop on meibomian gland dysfunction: report of the subcommittee on anatomy, physiology, and pathophysiology of the meibomian gland. Invest Ophthalmol Vis Sci 2011; 52: 1938-1978
• 16 Scope A, Benvenuto-Andrade C, Agero AL. et al. In vivo reflectance confocal microscopy imaging of melanocytic skin lesions: consensus terminology glossary and illustrative images. J Am Acad Dermatol 2007; 57: 644-658
• 17 Ilie MA, Caruntu C, Lixandru D. et al. In vivo confocal laser scanning microscopy imaging of skin inflammation: Clinical applications and research directions. Exp Ther Med 2019; 17: 1004-1011
• 18 Caruntu C, Boda D. Evaluation through in vivo reflectance confocal microscopy of the cutaneous neurogenic inflammatory reaction induced by capsaicin in human subjects. J Biomed Opt 2012; 17: 085003
• 19 Biggs LC, Kim CS, Miroshnikova YA. et al. Mechanical Forces in the Skin: Roles in Tissue Architecture, Stability, and Function. J Invest Dermatol 2020; 140: 284-290
• 20 Castro RPR, Casagrande Tavoloni Braga J, Petaccia de Macedo M. et al. Hotspot analysis by confocal microscopy can help to differentiate challenging melanocytic skin lesions. PLoS One 2022; 17: e0263819
• 21 Neves JR, Grether-Beck S, Krutmann J. et al. Efficacy of a topical serum containing L-ascorbic acid, neohesperidin, pycnogenol, tocopherol and hyaluronic acid in relation to skin aging signs. J Cosmet Dermatol 2022; 21: 4462-4469
• 22 Hofmann-Wellenhof R, Wurm EM, Ahlgrimm-Siess V. et al. Reflectance confocal microscopy–state-of-art and research overview. Semin Cutan Med Surg 2009; 28: 172-179
• 23 Scope A, Benvenuto-Andrade C, Agero AL. et al. Correlation of dermoscopic structures of melanocytic lesions to reflectance confocal microscopy. Arch Dermatol 2007; 143: 176-185
• 24 Ibrahim OM, Matsumoto Y, Dogru M. et al. The efficacy, sensitivity, and specificity of in vivo laser confocal microscopy in the diagnosis of meibomian gland dysfunction. Ophthalmology 2010; 117: 665-672
• 25 Cheng S, Yu Y, Chen J. et al. In vivo confocal microscopy assessment of meibomian glands microstructure in patients with Gravesʼ orbitopathy. BMC Ophthalmol 2021; 21: 261
• 26 Pan S, Chen Y. A clinical study on the correlation between demodex infestation and ocular surface changes in patients with meibomian gland dysfunction. Indian J Ophthalmol 2021; 69: 2389-2394
• 27 Yuan M, Zhang Q, Chang L. Applied research on confocal microscopy through focusing detection of tarsal glands shape following phacoemulsification for cataract. Am J Transl Res 2021; 13: 10744-10750
• 28 Kim J, Lim J. A Deep Neural Network-Based Method for Prediction of Dementia Using Big Data. Int J Environ Res Public Health 2021; 18: 5386