Dataset Information

Interspecies comparative morphological evaluation of the corneal epithelial stem cell niche: a pilot observational study.

ABSTRACT:

Background

The corneal and limbal morphology relevant to corneal epithelial maintenance in ten different species was examined using histological methods.

Objectives

The presence of a Bowman's layer, limbal epithelial cell, and superficial stromal morphology was examined in the following species to evaluate the differences in corneal thickness and epithelium: Java sparrows, frogs, macaws, spoonbills, red pandas, penguins, horses, Dobermans, orangutans, and humans.

Methods

Corneal sections (4 µm) were obtained from ten ocular globes from three different animal classes: Aves, Amphibia, and Mammalia. All sections were stained with hematoxylin and eosin and periodic acid-Schiff reaction. After microscopy, all stained slides were photographed and analyzed.

Results

Significant morphological differences in the corneal and limbal epithelia and their underlying stroma between species were observed. The number of corneal epithelial cell layers and the overall corneal epithelial thickness varied significantly among the species. The presence of a Bowman's layer was only observed in primates (orangutans and humans). Presumed supranuclear melanin caps were noted in four species (orangutans, macaws, red pandas, and horses) in the limbal basal epithelial layer (putative site of corneal epithelial stem cells). The melanin granules covered the apex of the cell nucleus.

Conclusions

Supranuclear melanin capping has been described as a process within the epidermis to reduce the concentration of ultraviolet-induced DNA photoproducts. Similarly, there may be a relationship between limbal stem cell melanin capping as a protective mechanism against ultra-violet radiation.

SUBMITTER: Popova P

PROVIDER: S-EPMC9346529 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Interspecies comparative morphological evaluation of the corneal epithelial stem cell niche: a pilot observational study.

Popova Petya P Malalana Fernando F Biddolph Simon S Ramos Tiago T Parekh Mohit M Chantrey Julian J Ahmad Sajjad S

Journal of veterinary science 20220701 4

<h4>Background</h4>The corneal and limbal morphology relevant to corneal epithelial maintenance in ten different species was examined using histological methods.<h4>Objectives</h4>The presence of a Bowman's layer, limbal epithelial cell, and superficial stromal morphology was examined in the following species to evaluate the differences in corneal thickness and epithelium: Java sparrows, frogs, macaws, spoonbills, red pandas, penguins, horses, Dobermans, orangutans, and humans.<h4>Methods</h4>Co ...[more]

PMID: 35920126

Similar Datasets

Project description:PurposeTo report the subjective assessment of topical self-administered, cadaver-derived corneal epithelial stem cell supernatant for treatment of severe dry eye disease (DED).MethodsThirty-four eyes of 17 patients with advanced DED as defined by Standardized Patient Evaluation of Eye Dryness (SPEEDTM) questionnaire ≥14, Ocular Surface Disease Index (OSDI©) score ≥40 and documented attempt of at least six conventional dry eye therapies were enrolled into a prospective clinical trial at a single private practice institution. Treatment consisted of patient self-administered topical instillation of the corneal epithelial stem cell-derived product four times daily in both eyes for 12 weeks. Patient-reported outcome measures (PROMs) were taken with the SPEEDTM questionnaire (the main outcome variable), OSDI© score and visual analog score (VAS; UNC Dry Eye Management Scale©), and objective clinical measurements were taken with best-corrected visual acuity (BCVA), corneal topographic index measurements and tear film osmolarity. These measurements were compared at baseline versus the endpoint at completion of the 12-week treatment.ResultsAll 34 eyes tolerated the treatment without any adverse events or significant side effects. Compared with baseline, both the SPEEDTM questionnaire and the VAS significantly improved at the conclusion of the 12-week treatment (p = 0.0054 and p = 0.0202, respectively). The OSDI© improved by an average of 10.9 points after the treatment but was not statistically significant (p = 0.1409). There were no significant changes in any of the objective clinical measurements. None of the study subjects failed to complete the treatment course, experienced decrease in any of the PROMs or lost one or more lines of BCVA during the follow-up period.ConclusionTopical corneal epithelial stem cell-derived supernatant that can be self-administered by the patient shows promise at improving patient symptoms and quality of life in the setting of severe DED that is unresponsive to conventional therapies.

Project description:BackgroundThe Limbal epithelial crypt (LEC) is a solid cord of cells, approximately 120 microns long. It arises from the undersurface of interpalisade rete ridges of the limbal palisades of Vogt and extends deeper into the limbal stroma parallel or perpendicular to the palisade. There are up to 6 or 7 such LEC, variably distributed along the limbus in each human eye. Morphological and immunohistochemical studies on the limbal epithelial crypt (LEC) have demonstrated the presence of limbal stem cells in this region. The purpose of this microarray study was to characterise the transcriptional profile of the LEC and compare with other ocular surface epithelial regions to support our hypothesis that LEC preferentially harbours stem cells (SC).ResultsLEC was found to be enriched for SC related Gene Ontology (GO) terms including those identified in quiescent adult SC, however similar to cornea, limbus had significant GO terms related to proliferating SC, transient amplifying cells (TAC) and differentiated cells (DC). LEC and limbus were metabolically dormant with low protein synthesis and downregulated cell cycling. Cornea had upregulated genes for cell cycling and self renewal such as FZD7, BTG1, CCNG, and STAT3 which were identified from other SC populations. Upregulated gene expression for growth factors, cytokines, WNT, Notch, TGF-Beta pathways involved in cell proliferation and differentiation were noted in cornea. LEC had highest number of expressed sequence tags (ESTs), downregulated and unknown genes, compared to other regions. Genes expressed in LEC such as CDH1, SERPINF1, LEF1, FRZB1, KRT19, SOD2, EGR1 are known to be involved in SC maintenance. Genes of interest, in LEC belonging to the category of cell adhesion molecules, WNT and Notch signalling pathway were validated with real-time PCR and immunofluorescence.ConclusionsOur transcriptional profiling study identifies the LEC as a preferential site for limbal SC with some characteristics suggesting that it could function as a 'SC niche' supporting quiescent SC. It also strengthens the evidence for the presence of "transient cells" in the corneal epithelium. These cells are immediate progeny of SC with self-renewal capacity and could be responsible for maintaining epithelial turn over in normal healthy conditions of the ocular surface (OS). The limbus has mixed population of differentiated and undifferentiated cells.

Project description:PurposeTo investigate the phenotypic changes of mature corneal epithelial cells (MCECs) that cocultured with limbal niche cells (LNCs) in three-dimensional Matrigel (3D Matrigel) in vitro.MethodsMCECs were isolated from central corneas, and limbal epithelial progenitor cells (LEPCs) were isolated from limbal segments with Dispase II. LNCs were isolated and cultured from limbal niche using the collagenase A digestion method and identified with PCK/VIM/CD90/CD105/SCF/PDGFRβ. MCECs were cultured on 3D Matrigel (50%, v/v) with or without LNCs for 10 days. Expression of CK12 and p63α and clone formation test were used to compare the progenitor phenotypic changes for MCECs before and after induction using LEPCs as control.ResultsHomogeneous LNCs were isolated and identified as spindle shape and adherent to a plastic surface coated with 5% Matrigel. Double immunostaining of the fourth-passage LNCs was uniformly PCK-/VIM+/CD90+/CD105+/SCF+/PDGFRβ+. Reverse transcription and quantitative real-time polymerase chain reaction (RT-qPCR) revealed the decrease of PCK expression from the second passage and elevation of Vim, CD90, CD105, SCF, and PDGFRβ transcripts from the third passage, and the transcription level of Vim, CD90, CD105, SCF, and PDGFRβ was elevated statistically in the fourth passage compared to the first passage (P < 0.01). Both immunofluorescence (IF) staining for cross section and cytospin cells demonstrated that MCECs expressed higher CK12 while lower p63α than LEPCs (P < 0.01). Sphere growth formation was noticed as early as 24 hours in the MCEC + LNC group, 48 hours in the LEPC group, and 72 hours in the MCEC group. The diameters of the spheres were the biggest in the MCEC + LNC group (182.24 ± 57.91 µm), smaller in the LEPC group (125.71 ± 41.20 µm), and smallest in the MCEC group (109.39 ± 34.85 µm) by the end of the 10-day culture (P < 0.01). Double immunostaining with CK12/p63α showed that cells in the sphere formed from MCECs expressed CK12 but not p63α; in contrast, some cells in the MCEC + LNC group expressed CK12, but most of them expressed p63α. RT-qPCR revealed a significant reduction of CK12 transcript but elevation of p63α, Oct4, Nanog, Sox2, and SSEA4 (P < 0.05). Holoclone composed of cubic epithelial cells could be generated in the MCEC + LNC group but not in the other two groups.ConclusionsThe data shows that human MCEC cell phenotype could be induced to the dedifferentiation stage when cocultured with LNCs in 3D Matrigel that simulated the microenvironment of limbal stem cells in vitro.

Dataset Information

Interspecies comparative morphological evaluation of the corneal epithelial stem cell niche: a pilot observational study.

Background

Objectives

Methods

Results

Conclusions

Publications

Interspecies comparative morphological evaluation of the corneal epithelial stem cell niche: a pilot observational study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets