Case report of restoration of the corneal epithelium in a patient with atopic keratoconjunctivitis resulting in amelioration of ocular allergic inflammation

Corneal fibroblasts: Function and markers

Corneal stromal keratocytes contribute to the maintenance of corneal transparency and shape by synthesizing and degrading extracellular matrix. They are quiescent in the healthy cornea, but they become activated in response to insults from the external environment that breach the corneal epithelium, with such activation being associated with phenotypic transformation into fibroblasts. Corneal fibroblasts (activated keratocytes) act as sentinel cells to sense various external stimuli-including damage-associated molecular patterns derived from injured cells, pathogen-associated molecular patterns of infectious microorganisms, and inflammatory mediators such as cytokines-under pathological conditions such as trauma, infection, and allergy. The expression of various chemokines and adhesion molecules by corneal fibroblasts determines the selective recruitment and activation of inflammatory cells in a manner dependent on the type of insult. In infectious keratitis, the interaction of corneal fibroblasts with various components of microbes and with cytokines derived from infiltrated inflammatory cells results in excessive degradation of stromal collagen and consequent corneal ulceration. Corneal fibroblasts distinguish between type 1 and type 2 inflammation through recognition of corresponding cytokines, with their activation by type 2 cytokines contributing to the pathogenesis of corneal lesions in severe ocular allergic diseases. Pharmacological targeting of corneal fibroblast function is thus a potential novel therapeutic approach to prevention of excessive corneal stromal inflammation, damage, and scarring.

Surgical debridement of corneal shield ulcers in pediatric patients: two case reports and a review of the literature

Background

Ocular allergy is a common disease, especially in the pediatric population, with unpleasant and long-term consequences, including corneal complications and decreased visual acuity. This study reports two cases of corneal shield ulcer due to vernal keratoconjunctivitis, with good results of surgical debridement performed after failure of long-term clinical treatment. Furthermore, this study highlights that this therapeutic approach, although less common, is efficient in treating refractory cases that cause suffering in pediatric patients.

Case presentation

The first patient was a 7-year-old Caucasian boy with chronic ocular allergy, especially photophobia, who had been treated with eye drops, antihistamine, and corticosteroids for 60 days without success. Biomicroscopy of the right eye showed the presence of gelatinous limbus, giant papillae in the tarsal conjunctiva, and a shield ulcer measuring 6.0 mm vertically and 2.7 mm horizontally. Surgical debridement was performed, and the ulcer did not recur. The second patient was a 4-year-old Caucasian boy with chronic ocular allergy, especially itching and photophobia, who had been treated with eye drops for 1 year without success. Biomicroscopy of the left eye showed a shield ulcer, with a dense central corneal plaque, measuring 8 mm vertically and 3.5 mm horizontally. Surgical debridement of the ulcer was performed immediately because of the chronicity of the case and severity of the lesion, and the treatment was effective.

Conclusions

The treatment of shield ulcers caused by vernal keratoconjunctivitis in the two reported cases was curative and definitive by surgical debridement in the 7-month follow-up period. Therefore, the early debridement of shield ulcers refractory to drug treatment can considerably reduce the time of disease evolution and the probability of ocular complications caused by clinical treatment or disease chronicity. However, this approach is rarely described in the literature and needs to be included in the ophthalmologist’s therapeutic arsenal.

Peptide therapies for ocular surface disturbances based on fibronectin-integrin interactions

The condition of the corneal epithelium is a critical determinant of corneal transparency and clear vision. The corneal epithelium serves as a barrier to protect the eye from external insults, with its smooth surface being essential for its optical properties. Disorders of the corneal epithelium include superficial punctate keratopathy, corneal erosion, and persistent epithelial defects (PEDs). The prompt resolution of these disorders is important for minimization of further damage to the cornea. Currently available treatment modalities for corneal epithelial disorders are based on protection of the ocular surface in order to allow natural healing to proceed. PEDs remain among the most difficult corneal conditions to treat, however. On the basis of characterization of the pathobiology of PEDs at the cell and molecular biological levels, we have strived to develop new modes of treatment for these defects. These treatments rely on two key concepts: provision of a substrate, such as the adhesive glycoprotein fibronectin, for the attachment and migration of corneal epithelial cells, and activation of these cells by biological agents such as the combination of substance P and insulin-like growth factor-1 (IGF-1). Central to both approaches is the role of the fibronectin-integrin system in corneal epithelial wound healing. Determination of the minimum amino acid sequences required for the promotion of corneal epithelial wound closure by fibronectin (PHSRN) and by substance P (FGLM-amide) plus IGF-1 (SSSR) has led to the development of peptide eyedrops for the treatment of PEDs that are free of adverse effects of the parent molecules.

Microtubules are required for efficient epithelial tight junction homeostasis and restoration

Epithelial tight junctions are critical for creating a barrier yet allowing paracellular transport. Although it is well established that the actin cytoskeleton is critical for preserving the dynamic organization of the tight junction and maintaining normal tight junction protein recycling, contributions of microtubules to tight junction organization and function remain undefined. The aim of this study is to determine the role of microtubules in tight junction homeostasis and restoration. Our data demonstrate that occludin traffics on microtubules and that microtubule disruption perturbs tight junction structure and function. Microtubules are also shown to be required for restoring barrier function following Ca(2+) chelation and repletion. These processes are mediated by proteins participating in microtubule minus-end-directed trafficking but not plus-end-directed trafficking. These studies show that microtubules participate in the preservation of epithelial tight junction structure and function and play a vital role in tight junction restoration, thus expanding our understanding of the regulation of tight junction physiology.

Surgical treatment of 32 cases of long-term atopic keratoconjunctivitis using the amniotic membrane

PURPOSE

To evaluate the use of surgical treatment with amniotic membrane for long-term atopic keratoconjunctivitis. Damaged corneas were repaired with various techniques: amniotic membrane transplantations, amniotic membrane coverings, amniotic membrane fillings (AMFs), and amniotic membrane inlay fillings, the latter of which were combined with glycerol-preserved corneal transplants.

METHODS

This retrospective study was conducted on 37 eyes belonging to 37 patients with atopic keratoconjunctivitis. Thirty-two patients were classified into four groups according to surgical technique. Five patients undergoing medical management served as controls. Surgical outcome was measured by recovery time and long-term visual improvement.

RESULTS

In all surgical eyes, integrity of ocular tissues was effectively restored and symptoms were reduced at 24.4 ± 13 days post recovery. Mean best-corrected visual acuity improved from 0.6 ± 0.2 to 0.198 ± 0.16 logarithm of the minimum angle of resolution (P<0.001). There were no intraoperative or postoperative complications, with the exception of two recurring cases, both controlled by medication. Recovery time of the control groups lasted 52 ± 16 days. In controls, mean best-corrected visual acuity improved from 0.74 ± 0.15 to 0.54 ± 0.29 logarithm of the minimum angle of resolution (P ≤ 0.05). The vision improvement has significant difference for surgical treatment vs medical. (Mann-Whitney U-test, U = 119, P < 0.05, one tailed).Vision improvements remained stable during a mean follow-up period of 21.7 ± 3.8 months.

CONCLUSION

Patients suffering from severe chronic atopic keratoconjunctivitis and its complications can benefit from suitable surgical treatments: transplants, covers, fillings, or corneal graft surgeries supplemented with AMFs.

Synergistic induction of eotaxin and VCAM-1 expression in human corneal fibroblasts by staphylococcal peptidoglycan and either IL-4 or IL-13

BACKGROUND

Common features of allergic or atopic ocular and skin diseases are the participation of Th2 lymphocytes and eosinophils and colonization by Staphylococcus aureus. To examine the role of interaction between Th2 cells and bacterial infection in tissue eosinophilia, we determined the effects of Th2 cytokines and peptidoglycan derived from the cell wall of S. aureus on corneal fibroblasts.

METHODS

Chemokine concentrations and the cell surface expression of adhesion molecules were determined by ELISAs, and chemokine and adhesion molecule mRNAs were quantitated by real-time PCR analysis. Signaling by the transcription factor NF-κB was evaluated by immunoblot and immunofluorescence analyses as well as by assay of DNA binding activity.

RESULTS

Among Th2 cytokines tested, only interleukin (IL)-4 and IL-13 induced a low level of eotaxin release by corneal fibroblasts, as did peptidoglycan. However, the combination of peptidoglycan and either IL-4 or IL-13 induced a marked synergistic increase both in eotaxin release (without affecting that of IL-8) and in the abundance of eotaxin mRNA. The combination of peptidoglycan and IL-4 or IL-13 also synergistically increased the surface expression of VCAM-1, but not that of ICAM-1. Peptidoglycan activated NF-κB in corneal fibroblasts, and inhibitors of NF-κB attenuated eotaxin release induced by peptidoglycan alone or in combination with IL-4 or IL-13.

CONCLUSIONS

Interaction of innate and adaptive immunity, as manifested by synergistic stimulation of eotaxin and VCAM-1 expression in corneal fibroblasts by peptidoglycan and Th2 cytokines, may play an important role in tissue eosinophilia associated with ocular allergy.