Herpetic Stromal Keratitis Research Articles

Suppression of Transcription Factor Early Growth Response 1 Reduces Herpes Simplex Virus 1-Induced Corneal Disease in Mice

Herpes simplex virus 1 replication initiates angiogenesis and inflammation in the cornea. This can result in herpetic stromal keratitis (HSK), which is a leading cause of infection-induced corneal blindness. Host cellular factors mediate the progression of HSK, but little is known about these cellular factors and their mechanisms of action. We show here that the expression of the cellular transcription factor early growth response 1 (Egr-1) in HSV-1-infected mouse corneas was enhanced. Enhanced Egr-1 expression aggravated HSK by increasing viral replication and subsequent neovascularization with high levels of potent angiogenic factors, fibroblast growth factor 2, and vascular endothelial growth factor. Furthermore, Egr-1 deficiency due to a targeted disruption of the gene or knockdown of Egr-1 expression topically using a DNA-based enzyme significantly reduced HSK by decreasing both viral replication and the angiogenic response. The present study provides the first evidence that endogenous Egr-1 aggravates HSK and that blocking Egr-1 reduces corneal damage.

Morphometric analysis of postoperative corneal neovascularization after high-risk keratoplasty: herpetic versus non-herpetic disease

Postoperative complications after high-risk corneal grafting are decisively associated with corneal neovascularization (CNV). This study aimed to identify the incidence, extent, speed, localization, and influence of surgery-related factors on CNV after high-risk penetrating keratoplasty (PK) and to evaluate the effect of removing the angiogenic stimulus, i.e., residual components of herpes simplex virus (HSV) on postkeratoplasty CNV in patients with herpetic stromal keratitis (HSK). All primary high-risk PK performed for HSK and non-herpetic keratitis (controls) between 1 January 1998 and 31 December 2003 at our department with available standardized corneal photographs taken preoperatively as well as 6weeks, 3, 6 and 12months postoperatively were evaluated (n (herpes) = 19, n (controls) = 5 patients). Maximal extension of CNV, limbus suture distance (LSD), limbus graft distance (LGD) and graft size in digitalized pictures were measured in each of the 16 sectors of the cornea at every visit. One hundred percent of the prevascularized corneas (n = 24) showed further CNV outgrowth within 1year after keratoplasty, while 58% of these patients featured high-grade CNV reaching the host-graft junction or invading the donor tissue. Overall, CNV outgrowth was fastest during the first 6weeks after PK, with a mean speed of 48μm/week. Mean CNV growth speed within 6months post-PK was significantly lower in the herpes group (13μm/week) than in the non-herpes group (25μm/week, p = 0.017). Corneal location around the 12 o'clock position showed the most intense vessel outgrowth, which proved to be an independent risk factor for high-grade CNV (p = 0.025). Inverse correlation was evident between CNV growth speed and LSD (p = 0.032). Additional intense CNV outgrowth is a common phenomenon after high-risk keratoplasty, strongly marked in the early postoperative period. The removal of residual HSV components representing a potential angiogenic stimulus leads to a reduction in corneal angiogenesis not in the short term, but in the long term after PK in patients with HSK. In addition to preferable atraumatic operation techniques, modern antiviral prophylaxis and anti-angiogenic therapy should be applied early, possibly even prior to transplantation. Short LSD seems to be an intraoperative adjustable risk factor for CNV in high-risk setting. Attention should also be paid to the superior site around the 12 o'clock position.

Monitoring the Inflammatory Process in Herpetic Stromal Keratitis: The Role of In Vivo Confocal Microscopy

To investigate the role of in vivo confocal microscopy (IVCM) in the detection of inflammatory activity and follow-up of herpetic stromal keratitis (HSK). Prospective observational cohort study. Thirty-eight patients with active HSK. Within 7 days after diagnosis of active HSK, both eyes of each patient were examined by slit-lamp biomicroscopy and white-light IVCM (Confoscan 4; Nidek Technologies, Padova, Italy). The HSK-affected eyes were followed up at 1, 3, 6, and 12 months, whereas the unaffected fellow eyes were reexamined after 12 months. Three patients did not complete follow-up and were excluded for data analyses. All IVCM examinations were assessed for morphologic alterations characteristic of inflammatory activity and for corneal backscatter. As secondary outcome parameters, best-corrected visual activity (BCVA), central corneal thickness (CCT), intraocular pressure (IOP), and endothelial cell density (ECD) were determined at each study visit. We used repeated-measures analysis of variance to assess changes during the 12-month follow-up period and paired t tests to compare HSK-affected eyes with fellow eyes. Presence of dendriform cells, pseudoguttae, and keratic precipitates, and follow-up of mean corneal backscatter. An increase of dendriform cells and pseudoguttae often accompanied stromal infiltration. Because these IVCM parameters were indiscernible or overlooked at slit-lamp examination, they proved to be excellent indicators of inflammatory activity. At 12 months' follow-up, mean corneal backscatter had decreased significantly by 36%, but still fell outside the normal range in 24 (69%) of the HSK-affected eyes. By using slit-lamp in conjunction with IVCM, we detected 17 recurrences in 14 of 35 patients (40%). Three of these recurrences were missed by slit-lamp, and 6 of these were missed by IVCM. At 12 months' follow-up, BCVA (-9 letters), CCT (-36 μm), and ECD (-313 cells/mm(2)) were significantly lower, whereas IOP (1.8 mmHg) was significantly higher, in HSK-affected eyes compared with fellow eyes. The data presented demonstrate that IVCM is complementary to slit-lamp examination in the follow-up of HSK, particularly because of its power to detect early signs of intracorneal inflammatory activity. Therapy guidance based on morphologic assessment and corneal backscatter measurement by combined IVCM and slit-lamp examination may improve the outcome of HSK. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Amniotic Membrane Induces Peroxisome Proliferator-Activated Receptor-γ Positive Alternatively Activated Macrophages

Amniotic membrane transplantation (AMT) reportedly improves herpetic stromal keratitis (HSK). Here we studied the role of the amniotic membrane (AM) on macrophages. BALB/c mice with necrotizing HSK received an AMT or tarsorrhaphy (TAR) as control. Apoptosis of F4/80+ cells was determined using the annexinV/7-AAD system. Macrophage invasion was determined using a cornea invasion assay. Cytokine secretion was quantified by ELISA. Arginase activity was measured by bioassay. Expression of nuclear factor (NF)-κB or peroxisome proliferator-activated receptor (PPAR)-γ related proteins was detected by Western blot analysis, and the expression of costimulatory surface molecules or PPAR-γ by flow cytometry. Lipid accumulation was observed by Oil red O and Sudan B staining. After AMT apoptotic features of corneal macrophages, but also macrophage invasion increased. IL-6, IL-10, IL-12, TNF-α, and NF-κB content in HSK corneas had decreased with AMT. AMT increased expression of PPAR-γ, arginase 1 and 2, and arginase activity in AM-treated HSK corneas. In vitro, NF-κB, cytokine production, costimulatory molecules (CD80, CD86, CD40), phagocytic capacity, proliferation, viability, and accessory function to herpes simplex virus (HSV)-1 specific draining lymph node (DLN) cells were reduced in bone marrow derived macrophages (BM) cocultured with AM, while CD206, CD204, CD163, and CD68, lipid accumulation in the cytoplasm, PPAR-γ expression, and arginase activity was increased. An increase in viability and proliferation was observed in the presence of AM combined with apoptotic cells, compared with AM alone. Based on these results it can be concluded that the action mechanism of AM is associated with modulation of classically activated macrophages into alternatively activated macrophages or macrophage cell death, probably by engaging lipid metabolism and activating the PPAR-γ pathway, consequently curtailing effector T cell functions. Apoptotic cells induced in the environment with AM support the presence and survival of such macrophages.

Therapeutic effect of deep anterior lamellar keratoplasty for active or quiescent herpetic stromal keratitis

To evaluate the therapeutic effect of deep anterior lamellar keratoplasty (DALK) in patients with herpetic stromal keratitis (HSK). Forty-three eyes belonging to 42 patients with HSK, including 22 eyes in the active phase and 21 eyes in the quiescent phase, underwent DALK at the Shandong Eye Institute from January 2006 to December 2009. All patients with active disease had received intravenous acyclovir and amniotic membrane implants prior to DALK. Herpes simplex virus type 1 (HSV-1) antigens from excised corneal buttons were detected by immunohistochemistry. The follow-up ranged from 1 to 4years (mean, 29.1months). Graft rejection occurred in one eye (2.3%) and was reversed. Among the other 42 survived grafts (97.7%), 37 remained clear at the last visit. The best spectacle-corrected visual acuity was 20/200 or better in 95.2% of eyes and 20/40 or better in 38.1% of eyes. Six eyes (14.0%) developed recurrent HSK, one of which received a second keratoplasty due to ineffective antiviral medication. There were no significant differences in endothelial cell density between 6months and 12months after the surgery. By immunohistochemistry, HSV-1 antigens were observed in the stroma of 18 of 32 corneal buttons. DALK can not only remove the corneal lesions of HSK but also reduce latent or persistent viral loads in the cornea. In eyes with active or quiescent HSK but otherwise healthy endothelia, DALK seems to be safe and promising for its favorable visual outcome, graft survival rate, and low endothelial cell loss.

Mice with Mutations in Fas and Fas Ligand Demonstrate Increased Herpetic Stromal Keratitis following Corneal Infection with HSV-1

HSV-1 infection of the cornea leads to a potentially blinding immunoinflammatory lesion of the cornea, termed herpetic stromal keratitis. It has also been shown that one of the factors limiting inflammation of the cornea is the presence of Fas ligand (FasL) on corneal epithelium and endothelium. In this study, the role played by FasL expression in the cornea following acute infection with HSV-1 was determined. Both BALB/c and C57BL/6 (B6) mice with HSV-1 infection were compared with their lpr and gld counterparts. Results indicated that mice bearing mutations in the Fas Ag (lpr) displayed the most severe disease, whereas the FasL-defective gld mouse displayed an intermediate phenotype. It was further demonstrated that increased disease was due to lack of Fas expression on bone marrow-derived cells. Of interest, although virus persisted slightly longer in the corneas of mice bearing lpr and gld mutations, the persistence of infectious virus in the trigeminal ganglia was the same for all strains infected. Further, B6 mice bearing lpr and gld mutations were also more resistant to virus-induced mortality than were wild-type B6 mice. Thus, neither disease nor mortality correlated with viral replication in these mice. Collectively, the findings indicate that the presence of FasL on the cornea restricts the entry of Fas(+) bone marrow-derived inflammatory cells and thus reduces the severity of HSK.

Recurrent Herpetic Stromal Keratitis in Mice: A Model for Studying Human HSK

Herpes simplex virus 1 (HSV-1) infection of the cornea leads to a potentially blinding disease, termed herpetic stromal keratitis (HSK) that is characterized by lesions of an immunoinflammatory nature. In spite of the fact that HSK typically presents as a recurrent disease due to reactivation of virus which latently infects the trigeminal ganglia, most murine studies of HSK have employed a primary and not recurrent model of the disease. This report documents the several recurrent models of HSK that have been developed and how data generated from these models differs in some important aspects from data generated following primary infection of the cornea. Chief among these differences is the fact that recurrent HSK takes place in the context of an animal that has a preexisting anti-HSV immune response, while primary HSK occurs in an animal that is developing such a response. We will document both differences and similarities that derive from this fundamental difference in these models with an eye towards possible vaccines and therapies that demonstrate promise in treating HSK.

Immunity to Ocular and Genital Herpes Simplex Viruses Infections

Hindawi Publishing Corporation Clinical and Developmental Immunology Volume 2012, Article ID 732546, 2 pages doi:10.1155/2012/732546 Editorial Immunity to Ocular and Genital Herpes Simplex Viruses Infections Aziz Alami Chentoufi, 1 Lbachir BenMohamed, 2 Philippe Van De Perre, 3 and Ali A. Ashkar 4 1 Pathology and Clinical Laboratory Medicine, Department of Immunology, King Fahad Medical City, Riyadh 11525, Saudi Arabia of Cellular and Molecular Immunology, Gavin Herbert Eye Institute, College of Medicine, University of California, Irvine, CA 92697-4375, USA 3 INSERM U 1058, Universit´ e Montpellier 1, 34090 Montpellier, France 4 Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Room MDCL4015, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1 2 Laboratory Correspondence should be addressed to Aziz Alami Chentoufi, aachentoufi@kfmc.med.sa Received 20 November 2012; Accepted 20 November 2012 Copyright © 2012 Aziz Alami Chentoufi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Herpes simplex virus type 1 and type 2 are amongst the most common human viral infection. Despite decades of research, currently, there is no vaccine or sterilizing therapy against human herpes. Both innate and adaptive immunities are required for protection against herpes infec- tions. However, the immunity and immunopathology of herpes infections are not yet fully characterized. To better understand the immunopathology of herpes infections and ultimately design an efficient prophylactic or therapeutic herpes vaccine or treatment, it is fundamental to define the cellular and molecular immune mechanisms and the immune correlates required for an efficient control of these ubiquitous pathogens. Over 400,000 Americans suffer from ocular herpes caused by HSV-1. Each year, nearly 50,000 new and recurring ocular herpes cases are diagnosed in the United States, with the more serious stromal keratitis accounting for about 25 percent. About 1 billion people— one-sixth of the world’s population—are infected with HSV- 2, the most common cause of genital herpes. In the United States, an estimated 50 million people carry the virus, and up to 3 million of those people suffer recurrent outbreaks of painful genital herpes. While the majority of HSV-1 and HSV-2 seropositive individuals is asymptomatic, a nonneg- ligible number of symptomatic individuals have as often as four recurrent herpes per year and required treatments. In addition, genital herpes has played an important role in driving the prevalence of other sexually transmitted infection such as HIV. Current drug therapies, often used to suppress genital herpes, can also treat ocular herpes but do not prevent future outbreaks. There is currently no prophylactic or therapeutic vaccine against herpes in the market. The impairment of T-cell function in acute and latent infection has been reported at many levels including abnormal antigen presentation in the periphery and in the sensory ganglia (trigeminal and lumbosacral ganglia), latently infected neuronal cells resistance to apoptosis by CD8+ T-cells, unbalanced immunoregulatory T-cell func- tion, and deregulation of Th1/Th2/Th17 axes. Despite the identification of many HSV-1 and HSV-2-antigens and their derived CD4+ and CD8+ T-cell epitopes, numerous antigen- specific therapies have failed when evaluated for their utility in the prevention and treatment of HSV infection. In this special issue, we invited authors to submit original research and review articles highlighting the recent advances that have broadened our understanding of immunity and immunopathology of herpes infection and HSV vaccine strategies. Also, we welcomed papers that seek to define immunoregulatory and effector properties of T-cells and dendritic cells to provide new insights as to their potential for clinical use. We were interested in articles that explore salient aspects of protective immunity throughout HSV latency, reactivation, ocular and genital herpetic disease, negative immunosynergy between HSV and HIV or other sexually transmitted diseases, and immunotherapeutical approaches. In a paper of this special issue, P. Stuart and T. Keadle documented the numerous recurrent models of herpetic stromal keratitis (HSK) that have been developed and how data generated from these models differs in some important

Substance P in the Corneal Stroma Regulates the Severity of Herpetic Stromal Keratitis Lesions

To determine whether substance P (SP) in herpes simplex virus-1 (HSV-1) infected cornea regulates the severity of herpetic stromal keratitis (HSK) lesions in a mouse model. C57BL/6 mice were infected ocularly with HSV-1 (RE). The corneas with HSK lesions, on Day 15 postinfection, were grouped on the basis of the corneal opacity as mild (≤2) or severe (>2). The amount of SP was determined in the corneas with mild or severe HSK lesions by enzyme immunosorbent assay (EIA) and confocal microscopy. Subconjunctival inoculation of spantide I, SP receptor antagonist, was carried out during the clinical phase of HSK. ELISA and flow cytometry were used to determine the level of cytokines, chemokines, and influx of immune cell types in the corneal lesions. The authors determined a significantly higher level of SP in the corneas with severe HSK lesions in comparison with mild lesions. The corneas with a higher level of SP also exhibited higher amounts of proinflammatory cytokines (IL-6, IFN-γ) and chemokines (CCL3, CXCL2) when compared with the corneas with a lower level of SP. SP receptor NK1R expression was determined in CD45- and CD45+ cells in infected cornea. SP present in the corneal stroma of the eyes with severe HSK lesions colocalized with β-III tubulin(+) and IA(b+) cell types. Subconjunctival inoculation of spantide I during the clinical phase of HSK resulted in significant reduction in the corneal opacity and angiogenesis. Collectively, these results demonstrate the relative contribution of substance P in regulating the clinical severity of HSK lesions in a mouse model.

Association of HSV-1 Antigen Distribution in the Cornea with Clinical Characteristics of Herpetic Stromal Keratitis

To investigate whether the clinical characteristics of stromal herpetic simplex keratitis (HSK) are associated with herpes simplex virus type 1 (HSV-1) antigens distribution in the pathologic cornea. Pathologic corneal buttons from 8 eyes were obtained during keratoplasty at the Shandong Eye Institute from 2006 to 2009. Immunohistochemical examination was performed to detect the distribution of HSV-1 antigens, including position, depth, and load in the cornea. Each of the 8 pathologic corneal buttons was positive for HSV-1 antigen by immunohistochemical staining, and HSV-1 antigen was detected in the corneal stroma but not in the corneal epithelium or endothelium. Combined with the clinical characteristics, it was found that the distribution depth of HSV-1 antigen in the cornea was partly related to the disease course, and the load was related to the delay time for treatment. Furthermore, HSK could be effectively cured by deep anterior lamellar keratoplasty (DALK). The distribution characteristics of HSV-1 in HSK corneal stroma supports the theory of HSV-1 latency in the cornea and guides the selection of DALK, rather than penetrating keratoplasty (PKP), for clinical stromal HSK treatment.

The Mechanisms and Consequences of Ultraviolet-Induced Immunosuppression in the Skin and Eye

Ultraviolet radiation (UVR) of the skin results in immune suppression to antigens encountered shortly after the exposure. The pathways leading to the downregulation in immunity are complex, initiated by chromophores located at the surface of the skin and ending with the generation of immunosuppressive mediators and regulatory cells. Ultraviolet-induced immunosuppression can be considered not only as beneficial, such as in preventing chronic inflammatory responses and allergic and automimmune reactions, but it can also be detrimental, such as in the lack of control of skin tumors and infectious diseases. The eye is an immune privileged site through a wide variety of mechanisms that allow selected immune responses without causing inflammation. The role of UVR in altering immune responses in the eye is not clear and is discussed in relation to photokeratitis, herpetic stromal keratitis, and pterygium.

Substance P, a key intermediate in the pathogenes Herpetic Stromal Keratitis (148.23)

Abstract Substance P (SP) is a pro-inflammatory neuropeptide that promotes chronic inflammation. In the current study, we ascertain the effects of blocking SP interaction with its receptor NK1R on the development of HSK lesion severity. Spantide I, a NK1R antagonist, is used for blocking SP-NK1R interaction in C57BL/6 mice after ocular HSV-1 infection. Infected mice were treated with Spantide I, either intra-peritoneally (IP) during pre-clinical (day 0-6) and clinical phases (day 7-15) or subconjuntivally (SC) during the clinical phase of the disease. Mice receiving IP or SC treatments during the clinical phase had a significant reduction in the development of corneal lesions. Corneas excised from these mice had a reduced number of neutrophils yet the number of CD4 T cells remained unchanged when compared to control mice. Additionally, IP administration of Spantide I reduced the frequency of IFNγ producing CD4 T cells in the spleen and cervical lymph nodes of infected mice, whereas SC treatments resulted in a lesser proportion of IFN-γ secreting CD4 T cells in the corneal stroma. Moreover, SC inoculation also resulted in a reduced proportion of IL-2 receptor (CD25) expressing CD4 T cells in the infected corneal tissue when compared to control mice. Taken together, our results show that blocking SP-NK1R interaction during the clinical phase of HSK inhibits the development of severe lesions by reducing CD4 T cell activation and number of neutrophils into the corneal stroma.

Amniotic membrane transplantation in refractory herpetic stromal keratitis accompanied with bacterial infection

Objective To evaluate the effects of amniotic membrane transplantation in refractory herpetic stromal keratitis accompanied with bacterial infection. Methods Twenty-three patients with refractory viral keratitis accompanied with bacterial infection were included in this study. All patients were given corneal scraping and confocal microscopy examination to exclude fungal and amoebal infection. After receiving 1 to 3 days of fortified antiviral and antibacterial treatment, the patients received amniotic membrane transplantation. The antiviral and antibacterial treatment continued with relatively fewer frequence postoperatively. Results The corneal ulcer resolved in all patient in 1 to 4 weeks postoperatively. Vision of all patients were improved compared with the preoperativeone. Conclusion Amniotic membrane transplantation can effectively diminish corneal inflammation and promote corneal healing. It is an effect treatment for refractory herpetic stromal keratitis accompanied with bacterial infection. Key words: amniotic membrane transplantation; herpetic stromal keratitis, viral; infection

A Case of Retained Graphite Anterior Chamber Foreign Body Masquerading as Stromal Keratitis

We report a case of a retained graphite anterior chamber foreign body that was masquerading as stromal keratitis. A 28-year-old male visited with complaints of visual disturbance and hyperemia in his right eye for four weeks. On initial examination, he presented with a stromal edema involving the inferior half of the cornea, epithelial microcysts, and moderate chamber inflammation. Suspecting herpetic stromal keratitis, he was treated with anti-viral and anti-inflammatory agents. One month after the initial visit, anterior chamber inflammation was improved and his visual acuity recovered to 20/20, but subtle corneal edema still remained. On tapering the medication, after three months, a foreign body was incidentally identified in the inferior chamber angle and was surgically removed resulting in complete resolution of corneal edema. The removed foreign body was a fragment of graphite and he subsequently disclosed a trauma with mechanical pencil 12 years earlier. This case showed that the presence of an anterior chamber foreign body should always be considered in the differential diagnosis of idiopathic localized corneal edema.

Herpetic keratitis: Herpes simplex virus versus host

AbstractHerpes simplex virus type 1 (HSV‐1) is an endemic virus worldwide that causes ocular disease in a limited but significant number of infected persons. Corneal HSV‐1 infection is clinically classified into herpetic epithelial keratitis (HEK) and herpetic stromal keratitis (HSK). HEK is an acute inflammation and results from viral toxicity of infected corneal epithelial cells. In contrast, HSK is characterized as a chronic immunopathogenic disease in which tissue injury and eventually blindness is due to the complex interplay between cells of the innate and adoptive immune response to viral antigens expressed in the corneal tissue. Studies performed on the experimental HSK mouse model greatly improved our understanding of the pathogenesis of HSK. This talk will recapitulate current insights on the virus‐host interactions involved in the initiation and perpetuation of herpetic keratitis in mice and men.

Osmolarity of tears in eyes affected by recurrent herpetic stromal keratitis

Abstract Purpose To assess the osmolarity of tears in eyes affected by recurrent herpetic stromal keratitis. Methods All the patients referred for a recurrent unilateral stromal keratitis infection by either Herpes simplex virus (VZV) or varicella‐zoster virus (VZV). All the patients have been finally tested for dry eye conditions when all clinical signs of ongoing keratitis had resolved. The osmolority was assessed using the TearLab® and then the corneal sensitivity was tested with the Cochet‐Bonnet esthesiometer (Luneau™). Values were compared using non‐parametric tests, and statistical significance was defined as p<0.05 (2‐tailed). Results Fifteen patients (mean age: 57 years +/‐ 11) were consecutively included in the study. The corneal sensitivity was strongly reduced in the affected side (9g/mm2 +/‐ 3.8) compared to the non‐affected side (0.55g/mm2 +/‐ 0.09, p=0.001). There was a trend (p=0.15) for a lower osmolarity in the affected eye (317.3 mosm/l +/‐ 6.2) compared to the non‐affected eye (321.2 mosm/l +/‐ 9.8), but the difference was not significant due to some affected eyes with high values of osmolarity. Indeed, we observed a relationship (p=0.1 for correlation test) between the loss of corneal sensitivity and the modification of tear osmolarity, with relative hypo‐osmolarity when corneal hyposesthesia was moderate and relative hyperosmolarity when corneal aesthesia was severly impaired. Conclusion This study suggests that recurrent stromal herpetic keratitis induces first an increase of tears production, as showed by hypo‐osmolarity with moderate relative hypoesthesia, and then a reduction of tears production when corneal sensitivity decreases below a threshold that remains to be more precisely defined.

Amnionmembrantransplantation bei herpetischen Hornhautinfektionen

Severe infectious corneal ulceration such as herpetic stromal keratitis commonly causes loss of vision and may lead to blindness. Treatment depending on the underlying disease includes antimicrobial medication and the development of surgical strategies to restore the integrity of the corneal ocular surface. Ulcerative herpetic stromal keratitis and/or neurotrophic keratopathy with the risk of corneal perforation are still clinically challenging conditions in ophthalmic surgery of the ocular surface. Since the introduction of newly developed preservation methods, amniotic membrane (AM) functioning as a basement membrane substitute has gained widespread popularity in ocular surface reconstruction. Various ways of clinical application such as the use of AM as a graft, patch or culture substrate and carrier system to expand ocular surface epithelia have been recently reported. In this article, the basis and clinical application of amniotic membrane transplantation for the management of corneal infections with Herpes simplex and Herpes zoster virus are reviewed.

Herpetic Stromal Keratitis (HSK) lesion severity correlates with the amount of pro-inflammatory neuropeptide Substance P in the cornea (42.21)

Abstract The cornea is richly supplied by nerve fibers that express a variety of biologically active neuropeptides. In this report, we looked into the possibility that after ocular herpes simplex virus-1 (HSV-1) infection of C57BL/6, the level of expression of neuropeptide SP in the cornea correlates with the development of HSK lesions. Our results showed that after ocular HSV-1 infection of C57BL/6 mice, about 60-70% of the infected corneas developed severe HSK lesions (corneal opacity ≥3 and angiogenesis ≥8) whereas, 30-40% developed mild HSK lesions (corneal opacity ≤1 and angiogenesis ≤5). No significant difference in the viral load was determined when analyzed between the corneas with mild or severe HSK lesions at different time-points post-infection. However, a strong influx of CD4 T cells and neutrophils were evident in the corneas with severe HSK lesions when compared to those with mild lesions at day 15 post-infection. In addition, corneas with mild HSK lesions had lower levels of IL-6, IL-2, IFN-g and IL-1 Ra in comparison to the corneas with severe HSK lesions as determined on day 15 post-infection. Most importantly, corneas with severe HSK lesions had significantly higher levels of neuropeptide SP in comparison those with mild HSK lesions, when determined on day 15 post-infection by using Immunofluorescence and EIA technique. We are looking into the possibility that neutralization of SP in the cornea impedes the development of severe HSK lesions in a mouse model.

Anti-VEGF monoclonal antibody-induced regression of corneal neovascularization and inflammation in a rabbit model of herpetic stromal keratitis

To determine the efficacy of bevacizumab (Avastin), an anti-VEGF monoclonal antibody, administrated via subconjunctival injection as a corneal anti-angiogenic treatment. Right corneas of rabbits were infected with herpes simplex virus type 1, KOS strain. On day 13 post-infection (p.i.), animals were treated subconjunctivally (sc) with a single 10-microl dose (25 microg/microl) of bevacizumab (group A) or with the same volume of an isotype monoclonal antibody, as negative control (group B). All animals were observed clinically on days 2, 5, 7, 14, 21, and 28 p.i., and two corneas each day were obtained for histological assessment and viral titration. Viral replication was observed no longer than 5 days after infection. By day 7 a dense neutrophil invasion of the cornea was detected, which significantly increased while herpetic stromal keratitis progressed in severity. Positive outcomes observed following the treatment with bevacizumab, compared to control, included: (1) Total involution of neovascularization, (2) reduction in disease severity, (3) improved corneal translucency, (4) absence of scarring, (5) preservation of corneal thickness, (6) no neutrophil infiltration of the cornea. Subconjunctival administration of bevacizumab induced involution of new vessels, abolished inflammatory response, and resulted in return of corneal function. Furthermore, bevacizumab is a novel approach for the treatment of herpetic stromal keratitis.

Amniotic Membrane Transplantation Induces Apoptosis in T Lymphocytes in Murine Corneas with Experimental Herpetic Stromal Keratitis

To investigate the effect of human amniotic membrane transplantation (AMT) on T-cell immune response in murine corneas with herpetic stromal keratitis (HSK). Herpes simplex virus (HSV)-1-infected BALB/c mice with necrotizing HSK were treated with AMT. CD3(+) cell apoptosis was determined in treated corneas and in vitro by flow cytometric analysis using the annexin V/7-AAD system. The effect of interleukin (IL)-2, cyclosporine, rapamycin, or Fas on T-cell survival was measured. Activation phenotype was measured by (3)H-thymidine uptake and flow cytometry (CD25, CD69, major histocompatibility complex class II). Cytokine/chemokine secretion from amniotic membrane (AM)-treated corneas or draining lymph node cells was measured. The immune-modulating capacity of long-term AMT treatment and adoptive transfer of AM-treated splenocytes was tested. After AMT, HSK and corneal inflammatory cell infiltration improved, and T-lymphocyte apoptosis occurred. T-cell apoptosis was also induced in vitro, independently of rIL-2, cyclosporine, rapamycin, or Fas. AMT-treated corneas and cultured lymphocytes had reduced IL-2, IL-10, IL-12, CRG-2, and CCL-2 content. Long-term AMT treatment decreased the proliferative response and type 1 helper T-cell cytokine level in draining lymph node cells. The improvement in HSK did not persist. Delayed-type hypersensitivity or HSV-1-specific cytotoxicity was not altered The results suggest that murine HSK improves after AMT through reduced local T-helper cell immune responses by inducing apoptosis in T lymphocytes, independently of passive apoptosis or activation-induced cell death. AM also reduces local T-helper cytokine and chemokine levels but does not result in immune deviation. Immunologic memory against HSV-1 is not affected by AMT, and long-term protection or tolerance is not induced.