Developing a model for aqueous deficient dry eye secondary to periglandular cicatrizing conjunctivitis.

PURPOSE: The current study used various techniques to develop a rabbit animal model of lacrimal gland damage caused by scarring conjunctivitis in the periglandular area. METHODS: Left eyes of New Zealand white rabbits were injected with 0.1 ml of 1M NaOH subconjunctivally around superior and inferior lacrimal gland orifices (Group 1, n = 4), touched with 1M NaOH for 100 s to the superior and inferior fornices with conjunctival denuding (Group 2; n = 4), and electrocauterization to the ductal opening area (Group 3; n = 4). The ocular surface staining, Schirmer I, lacrimal gland, and conjunctival changes were observed at baseline,1, 4, 8, and 12 weeks. The degree of glandular inflammation, conjunctival fibrosis (Masson Trichrome), and goblet cell density (PAS) were also assessed. RESULTS: At 12 weeks, the lacrimal glands of group 1 rabbits with periglandular injection showed severe inflammation with mean four foci/10HPF and a significant mean reduction in the Schirmer values by 7.6 mm (P = 0.007). Lacrimal glands had diffuse acinar atrophy, loss of myoepithelial cells, and ductular dilatation. The overlying conjunctiva showed fibrosis, goblet cell loss, and corneal vascularization in the inferotemporal quadrant. No lacrimal gland or ocular surface changes were observed in groups 2 and 3 at 12 weeks, except for localized subconjunctival fibrosis. CONCLUSION: Periglandular injection of 0.1 ml of 1M NaOH induced extensive lacrimal gland damage with reduced secretion and scarring in the subconjunctival plane compared to direct cauterization or direct NaOH contact to the ductal orifices of the rabbit lacrimal gland.

Human Lacrimal Gland Derived Mesenchymal Stem Cells - Isolation, Propagation, and Characterization.

Purpose: The existing treatment options for dry eye disease (DED) due to lacrimal gland (LG) dysfunction are mainly palliative. Mesenchymal stem cells (MSCs) based therapies and 3D-LG organoids have been explored as a curative option for LG regeneration in animal models. Human LG epithelial cultures are previously established and, here, we aim to isolate and characterize the spindle-shaped cells obtained from primary human LG cultures in order to unveil its MSC property. Methods: Normal human lacrimal glands were obtained from individuals undergoing LG debulking surgery. The conditions for human LG-MSC culture were standardized to obtain pure population of LG-MSCs at passage 3. Population doubling time (PDT), expression of phenotypic markers, tri-lineage differentiation, colony forming potential, and gene expression analysis were carried out to assess the phenotypic and genotypic characteristics compared to bone marrow-MSCs (BM-MSCs). Results: Our data show that these spindle-shaped cells exhibit similar phenotypic expression, colony-forming ability, and trilineage differentiation like BM-MSCs. Moreover, the gene expression also did not show any significant difference, except for increased IL1-ß in LG-MSCs. The LG-MSCs do not express any lacrimal epithelial markers unlike LG tissue. Conclusions: This study reveals the first-time evidence for the presence of MSC population within the human LGs, and these cells might play a role in maintaining healthy microenvironment within normal LG and repair in diseased LGs.

Expansion and characterization of human limbus-derived stromal/mesenchymal stem cells in xeno-free medium for therapeutic applications.

BACKGROUND: Mesenchymal stem cells (MSCs) have been proven to prevent and clear corneal scarring and limbal stem cell deficiency. However, using animal-derived serum in a culture medium raises the ethical and regulatory bar. This study aims to expand and characterize human limbus-derived stromal/mesenchymal stem cells (hLMSCs) for the first time in vitro in the xeno-free medium. METHODS: Limbal tissue was obtained from therapeutic grade corneoscleral rims and subjected to explant culture till tertiary passage in media with and without serum (STEM MACS XF; SM), to obtain pure hLMSCs. Population doubling time, cell proliferation, expression of phenotypic markers, tri-lineage differentiation, colony-forming potential and gene expression analysis were carried out to assess the retention of phenotypic and genotypic characteristics of hLMSCs. RESULTS: The serum-free medium supported the growth of hLMSCs, retaining similar morphology but a significantly lower doubling time of 23 h (*p < 0.01) compared to the control medium. FACS analysis demonstrated ≥ 90% hLMSCs were positive for CD90+, CD73+, CD105+, and ≤ 6% were positive for CD45-, CD34- and HLA-DR-. Immunofluorescence analysis confirmed similar expression of Pax6+, COL IV+, ABCG2+, ABCB5+, VIM+, CD90+, CD105+, CD73+, HLA-DR- and CD45-, αSMA- in both the media. Tri-lineage differentiation potential and gene expression of hLMSCs were retained similarly to that of the control medium. CONCLUSION: The findings of this study demonstrate successful isolation, characterization and culture optimization of hLMSCs for the first time in vitro in a serum-free environment. This will help in the future pre-clinical and clinical applications of MSCs in translational research.

Cytokeratin profile and keratinocyte gene expression in keratinized lid margins of patients with chronic Stevens-Johnson syndrome.

PURPOSE: To study the cytokeratin profile and keratinization-related gene expression in keratinized lid margins of chronic Stevens-Johnson syndrome (SJS) patients. METHODS: Posterior eyelid margins from 24 chronic SJS patients undergoing mucous membrane grafting and six healthy margins (orbital exenteration, fresh body donors) were studied using immunofluorescence staining (CK10, CK1, filaggrin, transglutaminase 1 (TGM1), (CK19, MUC5AC)) and quantitative PCR (keratinization-related genes-HBEGF, KGF, EGF, TGFα, TGFß, and TNFα). The staining and gene expression were studied separately in the lid margin epidermis (LME) and lid margin conjunctiva (LMC). RESULTS: The expression of CK 1/10, filaggrin, and TGM1 in the LMC was similar to the LME in SJS patients. CK19 was expressed only in the basal epithelial layer of the LMC with loss of MUC5AC expression. Increased expression of KGF (p ≤ 0.056), TNFα (p ≤ 0.02), and TGFα (p ≤ 0.01) was observed in the LME of SJS patients compared to normal LME. LMC of SJS patients showed an increased expression of HBEGF (p ≤ 0.002), EGF (p ≤ 0.0002), KGF (p ≤ 0.02), TNFα (p ≤ 0.04), TGFα (p ≤ 0.003), and TGFß (p ≤ 0.001) compared to normal LMC. Significant differences were observed in the expression of these genes between LME and LMC of SJS patients. These genes were validated using String analysis, which revealed the positive regulation of keratinization. CONCLUSION: In lid margins of SJS, there is an increased expression of keratinization-related genes compared to the normal lid margin. Keratinized LMC shares similar cytokeratin profile and keratinization gene expression as seen in cutaneous epithelium of SJS patients, indicating the possibility of the cutaneous epithelium as a source for keratinized LMC.

Clinical, histological and immunohistochemistry characteristics of cornea in the sequelae stage of chronic vernal keratoconjunctivitis.

PURPOSE: To report the clinical outcomes and histopathological and immunohistochemistry (IHC) features in eyes with the sequelae stage of vernal keratoconjunctivitis (VKC). METHODS: Investigative study of corneal samples obtained following surgical intervention for vision restoration in four eyes of three patients with VKC. Patient 1 (an 11-year-old boy) had deep anterior lamellar keratoplasty in both eyes, Patient 2 (a 24-year-old male) underwent superficial keratectomy followed by penetrating keratoplasty, and Patient 3 (a 22-year-old male) underwent penetrating keratoplasty. The corneal samples retrieved after surgical intervention were assessed for histology features and immunohistochemistry (IHC) studies. RESULTS: The grafts were clear till the follow-up of 2-18 months. Histopathology of all four corneal samples showed epithelial hyperplasia, absent Bowman layer, thick hyalinized stromal lamellae, vascularization, and chronic inflammatory cells such as lymphocytes and plasma cells. IHC showed strong expression of CK 3 in both eyes of Patient 1 and no expression in Patients 2 and 3. The marker for limbal stem cells, ABCG2, was absent in all four samples; however, p63α was expressed strongly in Patients 2 and 3, moderately in the right eye of Patient 1, and marginally expressed in the left eye of Patient 1. CONCLUSION: The eyes in the sequelae stage of VKC (having corneal scarring and 360° hypertrophied limbus) can be managed favorably with keratoplasty and amniotic membrane transplantation without allogenic/cadaveric stem cell transplantation. The expression of transient progenitor cells in the scarred corneas of VKC patients in the sequelae stage suggests that the limbal stem cell dysfunction is more likely partial and self-renewal of limbal stem cells is a plausibility in these eyes.