Ocular cicatricial pemphigoid associated with hyperproliferation of the conjunctival epithelium

Ocular cicatricial pemphigoid following Dipeptidyl Peptidase-4 inhibitor use: A case report

Purpose

To report a rare Ocular Cicatricial Pemphigoid (OCP) case in a patient taking a Dipeptidyl Peptidase-4 Inhibitor (DPP-4 inhibitor), a medication used for the management of type 2 diabetes, for at least six years.

Observations

A 64-year-old male presented with refractory bilateral conjunctival inflammation and ocular discharge that had persisted for two months, despite multiple prior therapies for presumed bacterial conjunctivitis. Upon initial examination, clinical findings strongly suggested OCP, and he had elevated levels of anti-BP180 antibodies. Despite receiving systemic treatments such as steroid pulse therapy and therapeutic plasma exchange after discontinuing DPP-4 inhibitors, his condition progressively worsened, with manifestations such as forniceal shortening in his left eye. Consequently, the patient required keratoepithelioplasty, amniotic membrane transplantation in his left eye, and bilateral eyelid entropion surgery. His condition initially worsened for a time after discontinuing the DPP-4 inhibitor, but it gradually improved over time, and ocular surface surgical intervention was not required in the right eye.

Conclusions and Importance

The findings in this study demonstrate that severe refractory OCP may occur while taking the DPP-4 inhibitor, thus indicating that a detailed interview regarding medications is essential for patients with ocular pemphigoid, especially those with type 2 diabetes.

Corneal epithelial development and homeostasis

The corneal epithelium (CE), the most anterior cellular structure of the eye, is a self-renewing stratified squamous tissue that protects the rest of the eye from external elements. Each cell in this exquisite three-dimensional structure needs to have proper polarity and positional awareness for the CE to serve as a transparent, refractive, and protective tissue. Recent studies have begun to elucidate the molecular and cellular events involved in the embryonic development, post-natal maturation, and homeostasis of the CE, and how they are regulated by a well-coordinated network of transcription factors. This review summarizes the status of related knowledge and aims to provide insight into the pathophysiology of disorders caused by disruption of CE development, and/or homeostasis.

The Efficacy of 2% Topical Rebamipide on Conjunctival Squamous Metaplasia and Goblet Cell Density in Dry Eye Disease

Purpose: To clarify the pharmacological effects of 2% rebamipide eye drops on mucosal membrane functions of the ocular surface epithelium, we investigated keratoconjunctival alterations at the cellular level in this study. Methods: Fifteen patients with definite dry eye disease were recruited from outpatient clinics of the Department of Ophthalmology, Ichikawa General Hospital. The patients received treatment with 2% rebamipide eye drops q.i.d for 12 weeks. Symptom score assessment, tear film breakup time, fluorescein and lissamine green ocular surface vital staining, grading of lid wiper epitheliopathy, Cochet-Bonnet corneal sensitivity, assessment of squamous metaplasia grades, and goblet cell density calculations from conjunctival impression cytology samples, as well as evaluation of nucleocytoplasmic ratios and corneal epithelial cells from in vivo confocal microscopy images before and 3 months after treatment were performed. Results: The mean symptom scores, tear film breakup time values, ocular surface fluorescein and lissamine green vital staining scores, and lid wiper scores showed a significant improvement after treatment (P < 0.01). The mean squamous metaplasia grade also showed a significant improvement (1.2 ± 0.1 → 0.3 ± 0.1) 3 months after treatment (P = 0.004). There were similar significant improvements in the mean corneal epithelial cell density (660.1 ± 62.6 → 1015.5 ± 43.5 cells/mm2) (P = 0.002) and nucleocytoplasmic ratios (0.1 ± 0.0 → 0.2 ± 0.0) (P = 0.0042) after treatment. Conclusions: Topical use of 2% rebamipide for 3 months was associated with improvements in ocular surface differentiation due to changes of mucosal functions at the cellular level. These alterations may explain objective and subjective improvements in dry eye disease.

Mouse conjunctival forniceal gene expression during postnatal development and its regulation by Kruppel-like factor 4

PURPOSE

To identify the changes in postnatal mouse conjunctival forniceal gene expression and their regulation by Klf4 during the eye-opening stage when the goblet cells first appear.

METHODS

Laser microdissection (LMD) was used to collect conjunctival forniceal cells from postnatal (PN) day 9, PN14 and PN20 wild-type (WT), and PN14 Klf4-conditional null (Klf4CN) mice, in which goblet cells are absent, developing, present, and missing, respectively. Microarrays were used to compare gene expression among these groups. Expression of selected genes was validated by quantitative RT-PCR, and spatiotemporal expression was assessed by in situ hybridization.

RESULTS

This study identified 668, 251, 1160, and 139 transcripts that were increased and 492, 377, 1419, and 57 transcripts that were decreased between PN9 and PN14, PN14 and PN20, PN9 and PN20, and PN14 WT and Klf4CN conjunctiva, respectively. Transcripts encoding transcription factors Spdef, FoxA1, and FoxA3 that regulate goblet cell development in other mucosal epithelia, and epithelium-specific Ets (ESE) transcription factor family members were increased during conjunctival development. Components of pathways related to the mesenchymal-epithelial transition, glycoprotein biosynthesis, mucosal immunity, signaling, and endocytic and neural regulation were increased during conjunctival development. Conjunctival Klf4 target genes differed significantly from the previously identified corneal Klf4 target genes, implying tissue-dependent regulatory targets for Klf4.

CONCLUSIONS

The changes in gene expression accompanying mouse conjunctival development were identified, and the role of Klf4 in this process was determined. This study provides new probes for examining conjunctival development and function and reveals that the gene regulatory network necessary for goblet cell development is conserved across different mucosal epithelia.

Evaluation of ocular surface changes in a rabbit dry eye model using a modified impression cytology technique

PURPOSE

To evaluate the ocular surface changes in a rabbit dry eye model by using a modified impression cytology technique.

METHODS

Nitrocellulose filter paper with a pore diameter of 0.45 microm was used to collect the specimens from 12 rabbits that were injected with atropine every day for 3 days. Filter papers were kept in distilled water overnight and then dried to increase cell pickup. Samples were stained with periodic acid-Schiff. The mean temporal and superior bulbar conjunctival goblet cell densities were counted. The data were compared with transmission (ocular surface) and scanning electron microscopic (filter paper) examination of the ocular surface.

RESULTS

In the acute stage of atropine injection, there was not a major change in the goblet cell count. Although the goblet cell distribution was variable over the ocular surface, the average cell density was 55.4+/-22 in the superior quadrant and 69.2+/-9 in the temporal quadrant. In the 3-day atropine-injection group, there was a marked decrease in goblet cells, and there was mucin accumulation rather than accumulation of the goblet cells. No morphologic differences could be observed with scanning electron microscopy between the regular nitrocellulose filter paper and the paper kept in distilled water.

CONCLUSIONS

The findings indicate that keeping the filter paper in distilled water and then drying it improves cell pickup and ocular surface evaluation in rabbits.

Tear lipocalin: evidence for a scavenging function to remove lipids from the human corneal surface

PURPOSE

Lipid contamination of the cornea may create an unwettable surface and result in desiccation of the corneal epithelium. Tear lipocalin (TL), also known as lipocalin-1, is the principal lipid-binding protein in tears. TL has been shown to scavenge lipids from hydrophobic surfaces. The hypothesis that TL can remove contaminating fatty acids and phospholipids from the human corneal surface was tested.

METHODS

TL was purified from pooled human tear samples by size exclusion and ion exchange chromatographies. Tears depleted of TL were reconstituted from fractions eluted by size exclusion chromatography that did not contain TL. Fresh and formalin-fixed human corneas were obtained from exenteration specimens. Fluorescent analogs of either palmitic acid or phosphatidylcholine were applied to the corneal epithelial surface. Tears, TL, or tears depleted of TL were applied over the corneas, and spectrofluorometry and fluorescent stereomicroscopy were used to monitor the removal of fluorescent lipids. Tears used in the experiments were then fractionated by size exclusion chromatography to determine the component of tears associated with fluorescent lipids.

RESULTS

Significant enhancement of fluorescence for 16AP and NBD C(6)-HPC was evident in solutions incubated with whole tears and purified TL but not with tears depleted of TL for fixed and unfixed corneas. After the experiment, size exclusion fractions of tears showed that the fluorescence component coeluted with TL.

CONCLUSIONS

TL scavenges lipids from the human corneal surface and delivers them into the aqueous phase of tears. TL may have an important role in removing lipids from the corneal surface to maintain the wettability and integrity of the ocular surface.

Distribution of mucins at the ocular surface

Mucins are vital for maintenance of a healthy, wet ocular surface. Once only thought to be secreted by goblet cells, mucins are now also known to be of the membrane-associated type. Stratified ocular surface epithelia express at their apical-tear fluid surface a repertoire of membrane-associated mucins including MUC1, MUC4, MUC16. These mucins are concentrated on the tips of the microplicae, forming a dense glycocalyx at the epithelial tear film interface. A major mucin of the secretory class is the goblet-cell-derived gel-forming mucin MUC5AC. A small soluble mucin, MUC7, is expressed by the lacrimal gland acini. Our hypothesis of the role/distribution of the secreted and membrane-associated mucins at the ocular surface is that the secreted mucins are soluble in the tear fluid, and are moved about and shunted to the nasolacrimal duct and by the eyelids during blinking. Thus, in the tears, the secreted mucins act as clean-up/debris removing multimeric networks that at the same time, through their hydrophilic nature, hold fluids in place and harbor defense molecules secreted by the lacrimal gland. Membrane-associated mucins, on the other hand, form a dense barrier in the glycocalyx at the epithelial tear film interface. This barrier prevents pathogen penetrance and is a lubricating surface that allows lid epithelia to glide over the corneal epithelia without adherence. The secreted mucins move easily over the glycocalyx mucins because both have anionic character that creates repulsive forces between them. Little is known regarding regulation of expression and glycosylation of mucins by ocular surface epithelia. Since ocular surface drying diseases alter both goblet cell and mucin production, and production and glycosylation of membrane-associated mucins, studies of mucin gene regulation and glycosylation may yield treatment modalities for these diseases.

Klassifikation der Erkrankungen der Augenoberfl�che

The ocular surface consists of the lid margin, conjunctiva and cornea which together with the tear system represent a functional entity. The diagnosis of ocular surface disease can be very difficult due to the similarity of various disease entities. The classification should be made on the pathological and pathophysiological characteristics of ocular surface disease. The first part of the classification comprises diseases of the lid margin, the tear system as well as diseases of the conjunctiva. Both the clinical presentation as well as the underlying pathophysiological and pathological characteristics of the most important ocular surface diseases are reviewed.

Role of Mucins in the Function of the Corneal and Conjunctival Epithelia

The surface of the eye is covered by a tear film, which is held in place by a wet-surfaced, stratified, corneal and conjunctival epithelia. Both are vital for light refraction and protection of vision. Maintenance of tear film on the ocular surface, lubrication, and provision of a pathogen barrier on this wet surface is facilitated by a class of large, highly glycosylated, hydrophilic glycoproteins--the mucins. In the past 15 years, a number of mucin genes have been cloned, and based on protein sequence, categorized as either secreted or membrane associated. Both types of mucins are expressed by ocular surface epithelia. Goblet cells intercalated within the stratified epithelium of the conjunctiva secrete the large gel-forming mucin MUC5AC, and lacrimal gland epithelia secrete the small soluble mucin MUC7. Apical cells of the stratified epithelium of both corneal and conjunctival epithelium express at least three membrane-associated mucins (MUCs 1, 4, and 16), which extend from their apical surface to form the thick glycocalyx at the epithelium-tear film interface. The current hypothesis regarding mucin function and tear film structure is that the secreted mucins form a hydrophilic blanket that moves over the glycocalyx of the ocular surface to clear debris and pathogens. Mucins of the glycocalyx prevent cell-cell and cell-pathogen adherence. The expression and glycosylation of mucins are altered in drying, keratinizing ocular surface diseases.

Epithelial hyperproliferation and transglutaminase 1 gene expression in Stevens-Johnson syndrome conjunctiva

In Stevens-Johnson syndrome, pathological keratinization of the ordinarily nonkeratinized corneal and conjunctival mucosal epithelia results in severe visual loss. We examined conjunctiva covering cornea in five eyes in the chronic cicatricial phase of Stevens-Johnson syndrome. Normal conjunctiva from five age-matched individuals was studied also. The number of epithelial cells in Stevens-Johnson syndrome conjunctiva that were immunoreactive with a monoclonal antibody, Ki-67, to a nuclear antigen found only in proliferating cells was greater than normal (93.8+/-19.8 cells above 100 basal cells versus 12.8+/-0.5 cells above 100 basal cells; P = 0.009). In addition, although clinical inflammation was mild, massive lymphocytic infiltration was seen in the substantia propria of conjunctiva covering cornea. In situ hybridization documented transglutaminase 1 (keratinocyte transglutaminase) mRNA in suprabasal cells of the abnormally thickened conjunctival epithelium in all Stevens-Johnson syndrome patients. In contrast, no message was detected in normal conjunctival or corneal epithelia. Transglutaminase 1 is expressed during the terminal differentiation of keratinocytes where it helps synthesize cornified cell envelopes. We speculate that in Stevens-Johnson syndrome, epithelial hyperproliferation, and transglutaminase 1 gene expression lead to the pathological keratinization of ocular surface mucosal epithelia.

Biological activity of N-(4-hydroxyphenyl) retinamide-O-glucuronide in corneal and conjunctival cells of rabbits and humans

Previous studies of topical retinoic acid for treatment of ocular surface disease met with limited success due to instability and irritancy of the retinoid and lack of efficacy in keratoconjunctivitis sicca. There has, however, been continued interest in the treatment of mucin deficiency and cicatrizing conjunctival diseases, such as ocular cicatricial pemphigoid (OCP), topically with retinoids. In this study the biological activity of stable, water-soluble, synthetic retinoid, N-(4-hydroxyphenyl) retinamide-O-glucuronide (4-HPROG) was investigated in vivo and in vitro using conjunctival and corneal epithelium and fibroblasts. Vitamin A-deficient rabbits with stage 3-4 corneal xerosis and squamous metaplasia confirmed by conjunctival impression cytology were treated with topical 0.1% 4-HPROG in an artificial tear vehicle for 3 weeks. Impression cytology was repeated at 2 and 3 weeks and at 3 weeks conjunctival biopsies were fixed for histology. Growth curves were generated using conjunctival fibroblasts of rabbits and humans (normals and patients with cicatrizing conjunctival disease including OCP and Stevens-Johnson syndrome) cultured in the 10(-8)-10(-6) M 4-HPROG. In vivo, corneal xerosis cleared in three days. A normal conjunctival epithelium was restored by 2 weeks and goblet cells were present by 3 wk, with no change in vehicle-treated controls. No ocular irritation occurred. In vitro, 10(-6) M 4-HPROG inhibits growth of rabbit conjunctival fibroblasts. The retinoid had no effect on proliferation of conjunctival fibroblasts from normal humans but the doubling time of cells from patients with OCP increased significantly, from 50.9 +/- 10.01 h (control) to 61.5 +/- 8.95 h (retinoid). Proliferation of conjunctival fibroblasts from a patient with Stevens-Johnson syndrome was also inhibited. N-(4-hydroxyphenyl) retinamide-O-glucuronide is biologically active and merits further study to determine its efficacy in controlling conjunctival fibrosis and treating ocular surface squamous metaplasia.

The ocular surface as part of the mucosal immune system: conjunctival mucosa-specific lymphocytes in ocular surface pathology

The mucosal immune system includes mucus membranes of the gut, respiratory and urogenital tracts. Mucosa-specific, intraepithelial lymphocytes (IELs), that correspond to the suppressor/cytotoxic subset and also express the human mucosal lymphocyte antigen (HML-1), are a unique component of this system. We have recently demonstrated these cells in the human conjunctiva, establishing the ocular surface as an integral part of the mucosal immune system. In this study we examined the distribution of lymphocyte subsets, with particular attention to mucosa-specific lymphocytes, in two ocular surface disorders, namely conjunctival intraepithelial neoplasia (CIN) and ocular cicatricial pemphigoid (OCP). Cryosections of biopsy specimen were immunostained using a panel of monoclonal antibodies against different lymphocyte subsets. In CIN, the CD8/HML ratio was decreased (1 +/- 0) and CD8/CD4 ratio was reversed (0.54 +/- 0.21). HML-1+ cells were distributed throughout the epithelial layers of dysplastic tissue. Biopsy specimens of OCP showed normal ratios of CD8/HML (1.4 +/- 0.16) but the CD8/CD4 was low (1.29 +/- 0.88). Association of HML-1+ cells with the basal layer of normal epithelium and with all layers of dysplastic epithelium suggests that expression of HML-1 antigen may be induced by actively dividing cells. HML-1+ cells may have a role in immune mechanisms associated with ocular surface disorders.

Conjunctival epithelial cell hypermitosis and goblet cell hyperplasia in atopic keratoconjunctivitis

Atopic diseases that include eczema (atopic dermatitis), asthma, and seasonal and perennial rhinoconjunctivitis are common manifestations of abnormal immediate hypersensitivity. Ocular involvement, such as atopic keratoconjunctivitis, characteristically includes conjunctival and corneal inflammation, and in a severe form, conjunctival scarring, symblepharon, corneal epitheliopathy, and visual loss. To examine the conjunctival cellular abnormalities in atopic keratoconjunctivitis, we studied the in vivo differentiation and tissue-culture growth characteristics of conjunctiva from normal subjects and patients with severe atopic keratoconjunctivitis. We examined conjunctival biopsy specimens to determine epithelial mitotic rate and goblet cell frequency, and we studied conjunctival explants to determine the latent period for fibroblast outgrowth and fibroblast doubling time. The mitotic rate for atopic keratoconjunctivitis, 6.7% +/- 2.1% (11 patients), was statistically significantly greater than for normal subjects, 2.0% +/- 0.63% (seven subjects) (P = .05). Also the goblet cell frequency for atopic keratoconjunctivitis, 14.6% +/- 3.4% (11 patients), was statistically significantly greater than for normal subjects, 4.8% +/- 0.92% (seven subjects) (P = .02). The latent period for fibroblast outgrowth and the fibroblast doubling time for atopic keratoconjunctivitis were not statistically significantly different from normal control subjects. Therefore, atopic keratoconjunctivitis was associated with conjunctival epithelial hypermitosis, goblet cell hyperplasia, and normal fibroblast tissue-culture growth. These characteristics may be useful in the diagnosis of atopic keratoconjunctivitis. We previously studied another disease characterized by chronic conjunctival inflammation and scarring, cicatricial pemphigoid, which also demonstrated conjunctival epithelial hypermitosis, but in contrast there was near absence of goblet cells, and the fibroblasts were hyperproliferative. These differences may be used to distinguish atopic keratoconjunctivitis from cicatricial pemphigoid.

Factors influencing in vivo trabecular cell replication as determined by 3H-thymidine labelling; an autoradiographic study in cats

Because trabecular cell loss is thought to play a role in the pathogenesis of some forms of glaucoma, identification of factors which influence trabecular cell division may provide some insight into the mechanisms and potential treatment of this disease. We studied several commonly encountered clinical situations which may affect the trabecular meshwork: phagocytosis of debris, hyphema, and argon laser trabeculoplasty. The effect of these factors on trabecular cell division was determined using 3H-thymidine autoradiography. Laser trabeculoplasty induced a 307% increase in 3H-thymidine labelling of trabecular cells while phagocytosis and hyphema had no effect on cell labelling. In addition, subgroups of eyes with a loss of trabecular cells or with inflammation did not have increased labelling. Thus laser trabeculoplasty, known to increase outflow facility, was associated with increased trabecular cell labelling while factors often associated with decreased outflow facility and glaucoma were not.

Cicatricial pemphigoid and erythema multiforme

Cicatricial pemphigoid (CP) and erythema multiforme (EM) are bullous diseases that involve the skin and mucous membranes including the conjunctiva. Of all the bullous diseases, CP and EM not only involve the conjunctiva most frequently but also cause the most severe conjunctival disease. A chronic, progressive disease, CP is characterized by shrinkage of the conjunctiva, symblepharon, entropion, trichiasis, dry eye, and finally reduced vision from corneal opacification. It is primarily a disease of the elderly that affects more women than men and is characterized by blisters or bullae in a subepithelial location and immunoglobulins and complement bound to the basement membrane zone of skin and mucous membranes including the conjunctiva. Circulating antibodies to the basement membrane zone can be demonstrated occasionally. Treatment includes artificial tears, topical antibiotics, correction of entropion and trichiasis, therapeutic soft contact lenses, and systemic immunosuppressive therapy including corticosteroids. An acute, generally self-limited, inflammatory disorder of the skin and mucous membranes, EM occurs primarily in young, healthy individuals. The most frequent precipitating factors are (1) drugs and (2) infections caused by Mycoplasma pneumoniae and herpes simplex. Conjunctival involvement ranges from a mild catarrhal conjunctivitis which terminates without sequelae to membranous conjunctivitis which may heal leaving scarring, symblepharon, and even ankyloblepharon. Histopathologic findings include subepithelial bullae and perivascular mononuclear cell infiltrates. Patients with EM have circulating immune complexes and immunoreactant deposition in the blood vessel walls of the dermis. After the acute episode has subsided, they may require artificial tears, topical antibiotics, correction of entropion and trichiasis, therapeutic soft contact lenses, tarsorrhaphy, and mucous membrane grafts.