Comparative Characterization of Human Meibomian Glands, Free Sebaceous Glands, and Hair-Associated Sebaceous Glands Based on Biomarkers, Analysis of Secretion Composition, and Gland Morphology

Atrophic meibomian gland dysfunction induced by eyelid margin cryotherapy with liquid nitrogen

To develop an atrophic Meibomian Gland Dysfunction (MGD) animal model via liquid nitrogen cryotherapy, the eyelid edges of C57 mice exposure to liquid nitrogen for 30 s. Morphology of MG and ocular surface were assessed using stereomicroscopy and a slit lamp microscope at multiple time points post-injury. Acinar loss and atrophy were observed from day 7, with increased inflammation and apoptosis, and decreased proliferation in acinar cells. Corneal epithelial defects appeared after day 14. Liquid nitrogen induced selective damage to meibomian acinar cells, simulating MGD pathology effectively, with peak effects at day 21, providing a relevant model for atrophic MGD research.

Pharmacological in vitro profiling of Buddleja officinalis flower extracts in the context of dry eye disease

BACKGROUND

Dry eye disease (DED) is caused by inflammation on the ocular surface and insufficient quality or production of the tear film. Due to various harmful environmental conditions, a gradual increase of DED cases has been reported.

HYPOTHESIS/PURPOSE

This study aims for a comprehensive in vitro pharmacological and phytochemical profiling of two different Buddleja officinalis Maxim. extracts to assess their potential for the treatment of DED.

METHODS

A hydroethanolic (BO-HE) and a lead-like enhanced (BO-LLE) B. officinalis extract were phytochemically characterized by UHPLC-UV-MS and UHPLC-ELSD analyses. Afterwards, the effects of either BO-HE or BO-LLE on in vitro dry eye models, including human corneal epithelial cell-transformed (HCE-T) cells, immortalized human meibomian gland epithelial cells (IHMGECs) and human leukemia monocytic (THP-1) cells, and Jurkat cells, were investigated.

RESULTS

Both extracts exhibited strong anti-inflammatory properties with free radical scavenging activities and reduction of intracellular reactive oxygen species (ROS) in UVB-exposed HCE-T cells. Treatment with BO-HE or BO-LLE showed wound healing capacities. Moreover, both extracts differentially modulate mediator secretion in UVB-exposed HCE-T cells. In IHMGECs, the size of secreted lipid droplets was larger in BO-LLE treated cells. As for immune cells, a significant reduction in levels of TNF-α and IL-6 secretion by lipopolysaccharide (LPS)-exposed THP-1 cells was observed. Additionally, BO-LLE effectively inhibited intracellular calcium influx in Jurkat cells even at low concentrations.

CONCLUSION

The results of this study demonstrate pharmacological potential of B. officinalis flowers for the treatment of DED pathology with BO-LLE exerting a slightly more beneficial profile than BO-HE.

The role of cell-cell and cell-matrix junctional complexes in sebaceous gland homeostasis and differentiation

Sebaceous glands (SG) are essential for maintaining skin integrity, as their lipid-rich secretion (sebum) lubricates and protects the epidermis and hairs. In addition, these glands have an emerging role in immunomodulation and may affect whole-body energy metabolism, besides being an appealing model for research in topics as lipogenesis, stem cell biology and tumorigenesis. In spite of the increasing interest in studying SGs pathophysiology, sebocyte cell-cell and cell-matrix adhesion processes have been only superficially examined, and never in a systematic way. This is regrettable considering the key role of cellular adhesion in general, the specific expression pattern of indivdual junctional complexes, and the reports of structural changes in SGs after altered expression of adhesion-relevant proteins. Here, we review the available information on structural and functional aspects of cell-cell and cell-matrix junctions in sebocytes, and how these processes change under pathological conditions. This information will contribute for better understanding sebocyte differentiation and sebum secretion, and may provide hints for novel therapeutic strategies for skin diseases.