Refractory Fungal Keratitis Caused by Acrophialophora fusispora: A Case Report and Literature Review.

Acrophialophora fusispora is a filamentous fungus that is found in soil and rarely infects humans. We herein report the first case of fungal keratitis caused by A. fusispora in Japan and present a review of the literature on human infections with Acrophialophora species. A 62-year-old Japanese male on immunosuppressive therapy developed fungal keratitis after the removal of a corneal foreign body from his left eye. Voriconazole eye drops and systemic therapy for post-traumatic fungal keratitis did not resolve the infection, and the patient required a therapeutic corneal transplant. The isolate was identified as A. fusispora based on the nucleotide sequence of the internal transcribed spacer region. In a drug susceptibility test, the minimum inhibitory concentration of voriconazole was 0.5 µg/mL. Based on this case and previous cases from the literature review, fungal keratitis caused by A. fusispora is often refractory.

Usefulness of smear microscopy for therapeutic decision-making in patients with infectious keratitis.

PURPOSE: To determine the usefulness of smears in the diagnosis of infectious keratitis by comparing smears and 2 different culture methods. STUDY DESIGN: Retrospective, observational study. METHODS: The foci of 73 patients diagnosed with infectious keratitis at Hiroshima University Hospital between July 2011 and September 2015 were abraded, and smear microscopy and culturing were performed. The microorganism detection rates and other parameters were compared. RESULTS: Microorganisms were detected in 47 of 73 specimens. Microorganisms were identified in 32 of 69 cases cultured on plain medium (detection rate, 46.4%) compared with 22 of 61 cases cultured on swab transport medium (detection rate, 36.1%). There was no significant difference in the microbial detection rate between the plain medium method and the swab transport medium method (P = 0.23). Smear microscopy and culture findings were concordant in 21 (28.8%) cases, and different microorganisms were detected in 9 cases. In 17 cases, the culture was negative, despite the presence of microorganisms on smear microscopy, and in 7 cases, the culture was positive, despite the absence of microorganisms on smear microscopy. The positivity rate of microbial detection was significantly higher when no antimicrobial agents had been administered previously (odds ratio 7.50, P = 0.017). CONCLUSION: Smear microscopy of abrasions from lesions is useful for the initiation of treatment for infectious keratitis. However, culture studies should be conducted at the same time to confirm antimicrobial sensitivity. If possible, smear microscopy should be performed before the initiation of antimicrobial therapy.

Corneal Copper Deposition Secondary to Monoclonal Gammopathy in a Patient With Chronic Lymphocytic Leukemia: A Case Report.

Hypercupremia-induced corneal copper deposition secondary to monoclonal gammopathy is rare and shows a characteristic corneal opacity quite different from other causes of hypercupremia, such as Wilson's disease. This report describes a case of corneal copper deposition in a patient with monoclonal gammopathy associated with chronic lymphocytic leukemia. An 84-year-old man with slowly progressive corneal opacity was referred to our hospital. The corneal opacity was present at least five years ago. The patient's best-corrected visual acuity was 20/25 OU (in both eyes) at the initial visit to our hospital. Slit-lamp examination and anterior segment optical coherence tomography revealed bilateral brown-colored opacity localized to deep layers of the central cornea. In vivo confocal microscopy (IVCM) showed indistinct corneal stromal cells in the deep layer and endothelial cells. The possible differential diagnoses were corneal dystrophy and Wilson's disease, but the color, shape, or site of corneal opacity was inconsistent with the disease. As the patient had a history of chronic lymphocytic leukemia, which is often associated with monoclonal gammopathy, we suspected that the corneal opacity was copper deposition in association with the hematologic diseases. Laboratory examinations showed elevated serum copper and normal ceruloplasmin. Serum protein electrophoresis revealed significantly high IgG levels with depression of IgA, IgE, and IgM. These results supported our diagnosis. Followingly, we consulted the patient's attending hematologist, and the doctor initiated treatment for hypercupremia. In conclusion, hypercupremia secondary to monoclonal gammopathy should be considered a possible cause of central brown-colored corneal opacity.

The Japan Cornea Society Survey of the Current Status of Corneal and Conjunctival Disorders Due to Systemic Antitumor Drugs.

Purpose: To investigate the current status of corneal and conjunctival disorders due to antitumor drugs in Japan. Methods: Questionnaires on corneal and conjunctival disorders due to antitumor drugs were sent to members of the Japan Cornea Society, and data on patients' background, clinical findings, treatment and prognosis of cases between January 2009 and December 2011 were collected and analyzed. Results: Out of all 221 cases from 66 facilities, TS-1Ⓡ had been administered in 210 cases (95.0%). Corneal findings were noted in 192 cases (86.9%), including 161cases (72.9%) of superficial punctate keratopathy, 55 cases (24.9%) of epithelial crack line, 38 cases (17.2%) of sheet-like epithelial abnormality, and 15 cases (6.8%) of corneal erosion. Conjunctival and ciliary findings were observed in 49 cases (22.2%). Lacrimal obstruction and constriction were found in 81cases (36.7%). Logistic regression analyses revealed the discontinuation and switching of antitumor drugs as the significant factor of good prognosis of clinical signs and visual acuity in cases with TS-1Ⓡ administration. Conclusions: Although corneal and conjunctival disorders due to antitumor drugs, especially TS-1Ⓡ, are important adverse effects, the only effective treatment at this time is the discontinuation and switching of antitumor drugs. Future prospective studies are needed to elucidate pathogenesis, aiming to the prediction and prevention of the occurrence.

Potential New Modes of Treatment of Neurotrophic Keratopathy.

The cornea focuses external light onto the retina, a function for which it must be transparent and possess a smooth surface. Homeostasis of the corneal epithelium is regulated by various humoral factors present in the tear fluid and by neural factors derived from the trigeminal nerve. Neurotrophic keratopathy (NK) is characterized by corneal epithelial disorders that result from impairment of trigeminal nerve function and a consequent deficiency of neural factors. The ideal mode of treatment for this condition is the regeneration of damaged trigeminal nerve fibers, but such therapy is not currently available. In this review, we describe established and potential new treatments of NK. Our research demonstrated that a combination of the neurotransmitter substance P and insulin-like growth factor 1 (IGF-1) has a synergistic stimulatory effect on corneal epithelial migration in vitro and on corneal wound closure in vivo. Furthermore, we identified the minimal amino acid sequences of substance P and IGF-1 required for this synergistic action based on the assumption that the clinical application of peptides corresponding to these sequences would have fewer side effects compared with the full-length molecules. Combination of the substance P-derived peptide FGLM-amide and the IGF-1-derived peptide SSSR promoted corneal epithelial wound healing in patients with NK.Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01756456.

Neuropeptides released from trigeminal neurons promote the stratification of human corneal epithelial cells.

PURPOSE: To examine the effects of neural cells on the stratification of and junctional protein expression by corneal epithelial cells with a coculture system. METHODS: PC12 cells induced to undergo neuronal differentiation or rat trigeminal nerve cells were cultured together with simian virus 40-transformed human corneal epithelial (HCE) cells on opposite sides of a collagen vitrigel membrane. Stratification of HCE cells was examined by immunofluorescence analysis with antibodies to zonula occludens-1. Expression of junctional proteins in HCE cells was assessed by RT-PCR and immunoblot analyses. RESULTS: The presence of neural cells (PC12 cells or trigeminal neurons) markedly promoted the stratification of HCE cells as well as increased the amounts of N-cadherin mRNA and protein in these cells. These effects of the neural cells were mimicked by conditioned medium prepared from differentiating PC12 cells or by the neuropeptides substance P and calcitonin gene-related peptide (CGRP). Furthermore, the stimulatory effects of trigeminal neurons on the stratification of and N-cadherin expression by HCE cells were inhibited by antagonists of substance P or of CGRP. CONCLUSIONS: These results suggest that trigeminal neurons play an important role in the differentiation of corneal epithelial cells. Neuropeptides released from these neurons may thus regulate adhesion between corneal epithelial cells and thereby contribute to the establishment and maintenance of corneal structure and function.

Matrix metalloproteinase and cytokine expression in Tenon fibroblasts during scar formation after glaucoma filtration or implant surgery in rats.

Failure of surgery for glaucoma is usually due to post-surgical scarring (fibrosis), a process in which fibroblasts play a prominent role. We investigated the molecular mechanisms of such scarring by examining the expression of matrix metalloproteinases and cytokines in Tenon fibroblasts isolated from rats after glaucoma surgery. Filtration surgery was performed in one eye and implant surgery in the other; and Tenon fibroblasts were isolated from the tissue surrounding the bleb after surgery. The cells were cultured and examined for the expression of matrix metalloproteinases (MMPs) by reverse transcription-polymerase chain reaction, immunoblot and gelatin zymographic analyses. Culture supernatants were also assayed for cytokines with a multiplex array. The amounts of MMP-1 and MMP-3 mRNAs and proteins were greater in cells isolated after implant surgery than in those isolated after filtration surgery, with the progression of scar formation being more complete after the former surgery. The secretion of interleukin-6 (IL-6) by cells isolated after filtration surgery was greater than that for cells isolated after implant surgery. Depletion of IL-6 by RNA interference in cells isolated after filtration surgery increased the expression of MMP-1 and MMP-3 in these cells. These results thus suggest that the expression of MMP-1 and MMP-3 in Tenon fibroblasts is regulated by IL-6 during, and may play an important role in, scar formation after glaucoma surgery.

Open clinical study of eye drops containing the fibronectin-derived peptide PHSRN for treatment of persistent corneal epithelial defects.

PURPOSE: We have previously shown that the fibronectin-derived peptide PHSRN (Pro-His-Ser-Arg-Asn) promotes corneal epithelial wound healing in vivo. We have now examined the clinical efficacy of eye drops containing the PHSRN peptide for treatment of persistent epithelial defects (PEDs) of the cornea. METHODS: Seven patients (5 men and 2 women; mean age±SD, 78.3±9.4 years) with PEDs were treated by administration of eye drops containing PHSRN. The duration of the PEDs before treatment was 7.4±5.5 weeks. The eye drops were administered as 1 drop per eye 4 times a day. Epithelial defects were observed with a slit-lamp microscope and photographed during the treatment course. RESULTS: Epithelial defects in 5 of the 7 affected eyes (71%) responded to PHSRN treatment as manifested by complete epithelial resurfacing within the 4-week period after treatment initiation. The mean±SD time required for complete epithelial resurfacing in the 5 responding subjects was 15.8±3.4 days. No adverse effects of treatment were observed in any of the subjects. CONCLUSIONS: Eye drops containing the fibronectin-derived PHSRN peptide are clinically efficacious for the treatment of PEDs.

[A case of anterior segment dysgenesis showing change in anterior eye features].

PURPOSE: Using an ultrasound biomicroscope (UBM) and an endoscope just after birth, We observed the morphological changes in the anterior segment in a case of anterior segment dysgenesis. CASE: The patient was a 9-day-old baby girl born with central opacity and high intraocular pressure. The central cornea was thin and the opacity was ring-shaped. Corneal vascularization was associated with the increase in the central corneal opacity, and finally progressed to fatty degeneration. Just after birth, UBM showed a double anterior chamber in one part of the cornea. The space in the cornea was filled with solid material, and the corneal thickness worsened. Surgical endoscopy showed a red membrane on the inner side of the cornea. The red color faded with time. CONCLUSION: We reasoned that an immature corneal stroma developed after birth, and that this secondary stroma filled the space between the retrocorneal membrane and the corneal stroma. We also reasoned that the red membrane of the posterior cornea might be caused by bleeding from the corneal neovascular vessels, or that the vascular membrane of the posterior cornea encouraged proliferation of collagen fibers. Later on the vessels and bleeding regressed.

Differential expression of semaphorin 3A and its receptors during mouse retinal development.

Semaphorins not only function in axon guidance during development but also contribute to various other biological processes. We have now examined the expression of semaphorin 3A (Sema3A) and its receptor components neuropilin 1 (Npn1) and plexin A (PlxA) during development of the mouse retina. Immunohistofluorescence analysis revealed that the expression patterns of Sema3A and Npn1 were similar during embryonic and postnatal development. The expression pattern of PlxA was also similar to those of Sema3A and Npn1 during embryonic and early postnatal (before eye opening) developments. However, the pattern of PlxA expression changed markedly after eye opening, with the expression disappearing from the optic nerve and increasing in intensity in the retinal pigment epithelium. Immunoprecipitation analysis showed that Sema3A interacted with PlxA in the retinal pigment epithelial cell line ARPE19 but not in the retinal ganglion cell line RGC5, whereas the opposite pattern of association was apparent for Sema3A and Npn1. Given that atmospheric oxygen is thought to play a role in the differentiation and maintenance of various ocular cell types, our results suggest that Sema3A-PlxA signalling activated by an effect of ambient oxygen on PlxA expression may contribute to differentiation of the retinal pigment epithelium.

Up-regulation of matrix metalloproteinase-1 and interleukin-6 expression in cocultures of corneal fibroblasts and neural cells.

The cornea is the most sensitive tissue in the human body, with the dense nerve endings of the cornea being derived from the first division of the ophthalmic nerve. The existence of such organized nerve fibers reflects the role of neural regulation in corneal homeostasis, with the proper distribution and function of these nerve fibers thus being required for maintenance of a healthy cornea. We recently established an in vitro model, based on the coculture of human corneal epithelial cells and fibroblasts on opposite sides of a collagen vitrigel membrane. We have now examined the role of neural cells in corneal homeostasis with the use of a similar coculture system. Reverse transcription-polymerase chain reaction and immunoblot analyses showed that the presence of neural cells (differentiated PC12 cells) increased the expression of matrix metalloproteinase-1 (MMP-1) in human corneal fibroblasts at both the mRNA and protein levels. The expression of MMP-2 and MMP-9 in corneal fibroblasts was not affected by PC12 cells. Furthermore, a multiplex assay showed that, among various cytokines assayed, only the release of interleukin-6 in cocultures of the two cell types was markedly greater than that in cultures of corneal fibroblasts alone. These results thus suggest that factors released from neural cells may play an important role in regulation of the function of corneal fibroblasts and thereby contribute to the maintenance of corneal structure and function.

Differential contributions of impaired corneal sensitivity and reduced tear secretion to corneal epithelial disorders.

BACKGROUND/AIMS: To determine the possible roles of impaired corneal sensitivity and reduced tear secretion in various types of corneal epithelial disorders. METHODS: A total of 99 patients (179 eyes) with corneal epithelial disorders classified as persistent epithelial defects (PED), corneal erosion, or superficial punctate keratopathy (SPK) and 115 individuals (230 eyes) without apparent ocular surface disorders (controls) were enrolled in a prospective study. Corneal sensitivity was measured with a Cochet-Bonnet esthesiometer, and tear secretion was measured by the Schirmer test in each subject. RESULTS: Corneal sensitivity of eyes in the PED and corneal erosion groups was significantly lower than that in the control group. Schirmer test values for eyes in the SPK group were significantly reduced compared with those in the control group. CONCLUSION: A loss of corneal sensitivity may contribute to the development of PED and corneal erosion, whereas reduced tear secretion may be a contributing factor for SPK. Both results indicate the importance of corneal sensory innervation to the maintenance of corneal integrity.

New mode of treatment for lattice corneal dystrophy type I: corneal epithelial debridement and fibronectin eye drops.

PURPOSE: The R124C mutation of the TGFBI gene gives rise to lattice corneal dystrophy type I, which is characterized by irregularity, turbulence, and opacity of the corneal epithelium. We investigated the efficacy of corneal epithelial debridement followed by application of autologous fibronectin eye drops in the treatment of patients with this mutation. METHODS: Four patients (6 eyes; age range 25-57 years) treated between April 2006 and March 2008 were enrolled in the study. All patients had impaired visual acuity and recurrent corneal erosion. Corneal epithelial debridement was performed with a spatula at the pupillary zone, after which eye drops containing fibronectin purified from autologous serum were administered four times daily for 2 weeks to promote epithelial migration. Topical levofloxacin and betamethasone were also applied four times daily for 1 month. RESULTS: All corneas achieved resurfacing within a few days of debridement. The best corrected visual acuity of all eyes improved from an average logMAR of 0.80 (range 1.40 logMAR-0.52 logMAR) before treatment to a logMAR of 0.10 (range 0.30 logMAR-0.046 logMAR) by 2-4 months after debridement. CONCLUSION: Despite the limitation of this study setting, corneal epithelial debridement followed by administration of fibronectin eye drops seems to be effective in improving visual acuity in cases of lattice corneal dystrophy type I caused by the R124C mutation of the TGFBI gene. This treatment may be one option for temporarily improving visual acuity in lattice corneal dystrophy type I and thus may delay the requirement for phototherapeutic keratoplasty or keratoplasty.

Effect of preoperative duration of stromal edema in bullous keratopathy on early visual acuity after endothelial keratoplasty.

PURPOSE: To clarify the relationship between visual acuity after Descemet-stripping automated endothelial keratoplasty (DSAEK) and the preoperative duration of stromal edema. SETTING: Yamaguchi University Hospital, Yamaguchi, Japan. DESIGN: Comparative case series. METHODS: Patients who had DSAEK were divided into 2 groups based on whether the preoperative duration of stromal edema was less than 12 months (Group A) or more than 12 months (Group B). No patient had postoperative conditions that might have affected postoperative visual outcomes. Postoperatively, the corrected distance visual acuity (CDVA) was measured and the morphology of the anterior cornea evaluated by in vivo laser confocal microscopy. RESULTS: The postoperative CDVA in Group A ranged from 20/50 to 20/16 at 3 months and from 20/66 to 20/16 at 6 months; the maximum CDVA was 20/40 to 20/13. The postoperative CDVA in Group B ranged from 20/66 to 20/40 at 3 months and 6 months; the maximum CDVA was 20/66 to 20/33. The structure of the anterior cornea was normal in patients in Group A but was abnormal with fibroblastic cells in the anterior stroma in patients in Group B. CONCLUSIONS: Patients with a preoperative duration of stromal edema of more than 12 months had pathologic changes in the corneal stroma that may have adversely affected visual acuity after DSAEK. Given that stromal edema, including that associated with bullous keratopathy, has been proposed to be a progressive condition, DSAEK may be most effective when performed early after the onset of edema, before the occurrence of pathologic changes in the stroma.

Long-term follow-up after lamellar keratoplasty in a patient with bilateral idiopathic corneal keloid.

PURPOSE: To report a case of bilateral idiopathic corneal keloid. METHODS: Retrospective review of clinical features, histopathological findings, clinical management, and outcome. RESULTS: A 2-year-old boy with bilateral corneal keloid was treated with lamellar keratoplasty and tranilast eye drops. Peripheral localized white corneal nodules had been present bilaterally since the age of approximately 6 months in the absence of any history of trauma, inflammatory disease, or relevant family history. Pathological examination of the excised corneal buttons revealed myofibroblast proliferation (positive staining for α-smooth muscle actins), a haphazard arrangement of collagen bundles, and the absence of inflammatory cells. On the basis of these findings, a diagnosis of corneal keloid was assigned. The size of the corneal lesion in the right eye decreased in response to therapy with tranilast eye drops. Lamellar keratoplasty resulted in improved bilateral visual acuity, which was maintained at the 12-year follow-up. CONCLUSIONS: This report describes a very rare case of bilateral corneal keloid in the absence of trauma or inflammation that was diagnosed by histological and immunohistochemical examination and electron microscopy. Good visual acuity was maintained over an extended period of postsurgery follow-up. Tranilast may represent a novel adjuvant therapy for corneal keloid.

Crosstalk between TGF-beta and MAPK signaling during corneal wound healing.

PURPOSE: The aim of this study was to elucidate the mechanisms governing epithelial cell migration and proliferation during wound healing. METHODS: The authors used wound healing of mouse corneal epithelium to examine the role TGF-ß signaling plays during the healing process. To achieve this goal, they used transgenic mice in which the TGF-ß receptor type II (Tbr2) was conditionally ablated from the corneal epithelium. Epithelium debridement wounds were made, followed by the assessment of cell migration, proliferation, and immunostaining of various signaling pathway components. RESULTS: The authors showed that in the absence of TGF-ß signaling corneal epithelial wound healing is delayed by 48 hours; this corresponds to a delay in p38MAPK activation. Despite the delayed p38MAPK activation, ATF2, a substrate of p38MAPK, is still phosphorylated, leading to the suppression of cell proliferation at the leading edge of the wound. These data provide evidence that in the absence of TGF-ß signaling, the suppression of cell proliferation during the early stages of wound healing is maintained through the JNK activation of ATF2. CONCLUSIONS; Together the data presented here demonstrate the importance of the TGF-ß and MAPK signaling pathways in corneal epithelial wound healing.

[Outcome of conjunctival autograft with amniotic membrane transplantation for recurrent pterygium].

PURPOSE: To investigate the outcome of conjunctival autograft with amniotic membrane transplantation without the use of mitomycin C for cases of recurrent pterygium. CASES AND METHODS: Thirty-nine eyes of 35 patients (aged 27 to 76 years) who underwent the surgical procedure for recurrent pterygium at Yamaguchi University Hospital from November 1998 to July 2007 were evaluated retrospectively from their medical records. Patients who did not undergo postoperative follow-up examination for at least 6 months were excluded. The mean number of prior surgeries was 2.9 (range, 2 to 10), and the mean +/- SD follow-up time was 42.0 +/- 29.6 months. RESULTS: Twenty seven of 29 eyes (93.1%) with recurrent grade 3 pterygium showed a reduction in the size of the new growth after surgery. The symblepharon improved postoperatively in 5 of 15 eyes (33.3%) and restriction of ocular movement improved in 11 of 24 eyes (45.8%). Most recurrences occurred within 6 months after surgery, although one case did not show a recurrence until 2 years postsurgery. CONCLUSION: Conjunctival autograft with amniotic membrane transplantation without the use of mitomycin C reduced the size of the recurrent pterygium. However, 6 of the 16 eyes (37.5%) required subsequent surgery, suggesting that the procedure has limitations. Mitomycin C should therefore possibly be considered for cases with severe symblepharon or restriction of ocular movement. In choosing the surgical procedure for recurrent pterygium, diplopia can be an important indicator of the severity of a symblepharon or restriction of ocular movement.

Three-dimensional analysis of collagen lamellae in the anterior stroma of the human cornea visualized by second harmonic generation imaging microscopy.

PURPOSE: The structure of collagen lamellae in the anterior stroma of the human cornea is thought to be an important determinant of corneal rigidity. The three-dimensional structure of such collagen lamellae in normal human corneas was examined. METHODS: The anterior portion of 27 normal human corneas was obtained from donor tissue for Descemet's stripping automated endothelial keratoplasty (DSAEK) surgery, and blocks (∼3-mm square) of the central cornea were examined by second harmonic generation (SHG) imaging microscopy. Each cornea was scanned from the surface of Bowman's layer to a depth of 150 µm, and SHG forward signals were collected. The angles of collagen lamellae immediately below to a depth of 30 µm below Bowman's layer (sutural lamellae) as well as of those at a depth of 50 or 100 µm were measured. The density and width of sutural lamellae were also evaluated. RESULTS: Collagen lamellae in the anterior stroma were evenly distributed and randomly oriented. The angle of sutural lamellae relative to Bowman's layer was 19.19 ± 4.34° (mean ± SD). The angles of collagen lamellae at depths of 50 or 100 µm were 8.91 ± 2.91 and 6.91 ± 2.11°, respectively. The density of sutural lamellae was 910.0 ± 480.4/mm(2), and their width was 13.14 ± 5.03 and 7.11 ± 3.00 µm in the region immediately beneath and 30 µm below Bowman's layer, respectively. CONCLUSIONS: Collagen lamellae in the anterior stroma of the normal human cornea are interwoven in three dimensions and adhere densely to Bowman's layer. This structure may contribute to the rigidity and curvature of the anterior portion of the cornea.

Expression of semaphorin 3A and its receptors during mouse corneal development.

Semaphorin 3A (Sema3A) functions to guide the growth of neurons during development, with its effects being mediated by receptor complexes composed of neuropilin (Npn) and plexin (Plx) proteins. We have now examined the expression of Sema3A and its receptor components Npn1 and PlxA during development of the mouse cornea. Sema3A and Npn1 showed similar patterns of expression by immunohistofluorescence analysis, with such expression being prominent in the corneal epithelium during both embryonic and postnatal development. In contrast, PlxA was not expressed in the corneal epithelium until after eye opening between postnatal days 12 and 14. Laser capture microdissection followed by reverse transcription and polymerase chain reaction analysis also showed that the abundance of PlxA mRNA in corneal epithelial cells increased significantly during postnatal development, again in association with eye opening. Given that atmospheric oxygen is thought to play a role in corneal epithelial differentiation and maintenance, our results suggest that the up-regulation of PlxA expression in the corneal epithelium during postnatal development is triggered by exposure of the cornea to the atmosphere. Furthermore, the newly expressed PlxA may contribute to the differentiation of corneal epithelial cells by mediating Sema3A signaling.

Lumican is required for neutrophil extravasation following corneal injury and wound healing.

An important aspect of wound healing is the recruitment of neutrophils to the site of infection or tissue injury. Lumican, an extracellular matrix component belonging to the small leucine rich proteoglycan (SLRP) family, is one of the major keratan sulfate proteoglycans (KSPGs) within the corneal stroma. Increasing evidence indicates that lumican can serve as a regulatory molecule for several cellular processes, including cell proliferation and migration. In the present study, we addressed the role of lumican in the process of extravasation of polymorphonuclear leukocytes (PMNs) during the early inflammatory phase present in the healing of the corneal epithelium following debridement. We used Lum(-/-) mice and a novel transgenic mouse, Lum(-/-),Kera-Lum, which expresses lumican only in the corneal stroma, to assess the role of lumican in PMN extravasation into injured corneas. Our results showed that PMNs did not readily invade injured corneas of Lum(-/-) mice and this defect was rescued by the expression of lumican in the corneas of Lum(-/-),Kera-Lum mice. The presence of lumican in situ facilitates PMN infiltration into the peritoneal cavity in casein-induced inflammation. Our findings are consistent with the notion that in addition to regulating the collagen fibril architecture, lumican acts to aid neutrophil recruitment and invasion following corneal damage and inflammation.