Full-thickness Corneal Transplantation Research Articles

Pseudochamber-Protected Keratoplasty (PPK) with a New Inter-Corneal Surgical Device Implant Technique in High-Risk Cases.

Background/Objectives: To describe the pseudochamber-protected keratoplasty (PPK) procedure with the new Endo-K Pro® implant technique and report the clinical outcomes in patients at high risk for penetrating keratoplasty (PKP). Methods: This case series study included patients who required a PKP and had a high risk for corneal transplant failure. All cases underwent the PPK procedure with simultaneous Endo-K Pro® implantation and had a minimum follow-up of 12 months. Graft survival was the primary outcome (defined as a clear graft with an endothelial cell density >500 cells/mm2). Central corneal thickness (CCT), corrected distance visual acuity (CDVA), intraocular pressure (IOP), and complication rate were the secondary outcomes. Results: Twenty-five eyes (twenty-five patients) were included. The mean follow-up was 23.64 ± 8.2 months (range: 12-36 months). Graft survival was achieved in 23 of the 25 cases (92%). One eye had to be re-transplanted due to persistent oedema secondary to uncontrolled IOP. In two cases (8%), the graft failed three months after surgery when an anterior pseudochamber collapsed due to direct contact of donor endothelium and host tissue. Six eyes experienced host tissue protrusion that was successfully managed using an Nd: YAG laser (two eyes) or injecting a cohesive viscoelastic into the pseudochamber (four eyes). CDVA increased significantly during the follow-up period. No significant changes were found in IOP. No intra- or postoperative complications were reported. Conclusions: PPK with the Endo-K Pro® implant seems to be an effective and safe surgical approach as an alternative in high-risk patients for PKP, allowing full-thickness corneal transplantation without performing an open-sky procedure.

Attach importance to the orderly development of different corneal transplant procedures

There are various surgical methods for corneal transplantation, each requiring precise treatment tailored to the characteristics and different layers of corneal opacity or lesions. These layers include the corneal epithelium, stroma (lamellar), and corneal endothelium, with options for full-thickness (penetrating) corneal transplantation or artificial corneal transplantation. However, a current issue in clinical practice is that, regardless of the degree of corneal disease, the availability of corresponding eye bank support, or surgical conditions, classic penetrating (full-thickness) corneal transplantation is universally performed. Alternatively, there is a trend toward adopting technically demanding procedures such as endothelial transplantation and artificial corneal transplantation. This trend has led to increased postoperative complications and the wastage of corneal donor materials. Choosing the appropriate corneal transplant procedure can offer advantages such as preserving more healthy corneal tissue, conserving corneal donors, facilitating rapid vision recovery, and minimizing the risk of immune rejection. Corneologists need to master the indications for various corneal transplant surgeries and systematically perform different corneal transplant procedures based on the surgeon's skills, hospital conditions, and eye bank conditions. This approach aims to enhance the success rate of the surgery.

Identification and Management of a Novel PRDM5 Gene Pathologic Variant in a Family With Brittle Cornea Syndrome.

The aim of this study was to report a novel PRDM5 pathologic variant and ophthalmic findings in a family with 3 children diagnosed with brittle cornea syndrome (BCS). Histopathologic findings and surgical outcome of a child with BCS who underwent full-thickness corneal transplant are described. This is an observational case report of a nonconsanguineous Laotian family with 3 siblings diagnosed with BCS. Data collected included visual acuity, cycloplegic refraction, slit-lamp biomicroscopy, dilated fundus examination, corneal pachymetry, corneal topography, and general medical findings. Targeted testing through PRDM5 gene sequencing with copy number variation detection was conducted. The 3 siblings included a 12-year-old boy and 8- and 6-year-old sisters, all of whom presented with myopia, blue-tinted sclerae, thin corneas, and variable corneal scarring. All 3 affected children were found to be homozygous for the PRDM5 gene variant c.1117_1123delinsTTTAATGCTTACAAATGTTTG p.Asp373Phefs*57. Coding sequences of PRDM5 and ZNF469 genes were sequenced in their entirety, and this was the only pathologic variant present in this family. The youngest affected sister developed persistent hydrops with severely decreased vision and underwent penetrating keratoplasty. Histopathology revealed severe corneal thinning, diffuse absence of Bowman layer, and ruptured Descemet membrane scrolls. Three siblings with clinical signs of BCS, including corneal thinning, myopia, and blue sclerae, were found to have a novel PRDM5 gene pathologic variant. This pathologic variant has not been previously reported, although 1 downstream nonsense pathologic variant has been reported as pathogenic. The similar phenotypes in all affected patients support the pathogenicity of this variant. Surgical management of BCS presents unique challenges due to severe tissue fragility.

Case Report: Simultaneous penetrating keratoplasty with autologous simple limbal epithelial transplantation as an alternative to keratoprosthesis

Introduction and importance: This case report highlights the multidisciplinary approach required to achieve successful anatomical and functional outcomes, in an eye with total limbal stem cell deficiency (LSCD) associated with underlying corneal scarring and thinning. Presentation of case: A 59-year-old gentleman had poor visual recovery in the right eye (RE) following accidental carbide blast, 1-year before presenting to us. The visual acuity was counting fingers and clinical examination revealed cicatricial entropion involving the upper eyelid, total LSCD, corneal scarring with a central descemetocele and cataract in the RE. Prior to ocular surface reconstruction, entropion correction was performed. Three months later, penetrating keratoplasty combined with cataract surgery and intraocular lens implantation (penetrating keratoplasty (PK) triple), with autologous simple limbal epithelial transplantation (SLET) was performed. The visual acuity was 20/100, 18 months after the surgery, with a clear well-epithelized corneal graft and stable ocular surface. Discussion: LSCD is caused by a decrease in the population and /or function of the limbal epithelial stem cells. Limbal stem cell transplantation (LSCT) is warranted in eyes with total LSCD. In eyes with coexisting corneal scarring, LSCT alone may be inadequate to restore the vision. These eyes require simultaneous or sequential lamellar or full-thickness corneal transplantation for visual rehabilitation. Though, the existing literature favors a sequential approach, where LSCT is performed first followed by corneal transplantation, under certain circumstances such as a thin underlying cornea like in our case, corneal transplantation may have to be combined with LSCT to achieve optimal outcomes. Conclusion: Combining autologous SLET with PK can be performed for visual rehabilitation in eyes with unilateral total LSCD and underlying corneal thinning. Corneal and limbal graft survival is prolonged if existing adnexal comorbidities are addressed before any surgical intervention is planned and adequate time interval is allowed for the surface inflammation to subside.

Case Report: Simultaneous penetrating keratoplasty with autologous simple limbal epithelial transplantation as an alternative to keratoprosthesis

Introduction and importance: This case report highlights the multidisciplinary approach required to achieve successful anatomical and functional outcomes, in an eye with total limbal stem cell deficiency (LSCD) associated with underlying corneal scarring and thinning. Presentation of case: A 59-year-old gentleman had poor visual recovery in the right eye (RE) following accidental carbide blast, 1-year before presenting to us. The visual acuity was counting fingers and clinical examination revealed cicatricial entropion involving the upper eyelid, total LSCD, corneal scarring with a central descemetocele and cataract in the RE. Prior to ocular surface reconstruction, entropion correction was performed. Three months later, penetrating keratoplasty combined with cataract surgery and intraocular lens implantation (penetrating keratoplasty (PK) triple), with autologous simple limbal epithelial transplantation (SLET) was performed. The visual acuity was 20/100, 18 months after the surgery, with a clear well-epithelized corneal graft and stable ocular surface. Discussion: LSCD is caused by a decrease in the population and /or function of the limbal epithelial stem cells. Limbal stem cell transplantation (LSCT) is warranted in eyes with total LSCD. In eyes with coexisting corneal scarring, LSCT alone may be inadequate to restore the vision. These eyes require simultaneous or sequential lamellar or full-thickness corneal transplantation for visual rehabilitation. Though, the existing literature favors a sequential approach, where LSCT is performed first followed by corneal transplantation, under certain circumstances such as a thin underlying cornea like in our case, corneal transplantation may have to be combined with LSCT to achieve optimal outcomes. Conclusion: Combining autologous SLET with PK can be performed for visual rehabilitation in eyes with unilateral total LSCD and underlying corneal thinning. Corneal and limbal graft survival is prolonged if existing adnexal comorbidities are addressed before any surgical intervention is planned and adequate time interval is allowed for the surface inflammation to subside.

Vogt striae: Demystified

BackgroundTo study the correlation of different variables of Vogt striae to other attributes of keratoconus and to suggest a new grading system for Vogt striae to exactly represent the configuration and extent in each individual keratoconic cornea. MethodsThe study was an observational and data review study. A total of 386 eyes of 207 keratoconus patients were screened from February 2016 to August 2018. Patients with prior history of collagen cross linking were excluded from the study as measurement of corneal thickness is less reliable for many months after collagen cross linking, and patients may have superficial corneal striae and scarring after collagen cross linking. Patients with history or clinical features suggestive of corneal hydrops or who had undergone lamellar or full thickness corneal transplants and intracorneal ring segments were also excluded from the study. ResultsOf total 52 eyes with Vogt striae, 31 eyes (59.6%) had vertical orientation, 3 (5.8%) had horizontal, 11 (21.2%) had oblique while 7 eyes (13.5%) had mixed orientation of Vogt striae. Mean uncorrected distance visual acuity (UCVA) in the vertical group was 0.76 logMAR, horizontal group was 0.80 logMAR, oblique group was 0.65 logMAR, and mixed group was 1.17 logMAR units. Corneal scarring was present in 15 eyes (28.8%) and absent in 37 (71.2%) eyes with Vogt striae. In the mixed Vogt striae group, 85.7% eyes (6 eyes of 7) had corneal scarring, while 16.1% in vertical group (5 eyes of 31), and 27.3% in oblique group (3 of 11) had corneal scarring. Based on three attributes of Vogt striae, that is orientation, number, and corneal scarring, a new grading for Vogt striae was also suggested. ConclusionThis is the first study to report the presence of mixed Vogt striae (combination of horizontal and/or vertical and/or oblique Vogt striae in a single cornea) in cases of keratoconus. For the first time, oblique Vogt striae have been described, and clear limits have been set to call it horizontal, oblique, or vertical striae. A new grading for Vogt striae is also suggested.

New findings on the immune response following corneal transplantation

AbstractWe performed a multi‐centre, cross‐sectional analysis of the current immunological status of human full thickness (FT) and posterior lamellar (PL) corneal transplant (CT) recipients and control subjects using multiple technology platforms. The primary goal of this study was to define pathways associated with adverse immune responses to corneal transplantation and to generate and compare comprehensive, pathway‐based profiles of immune activity in CT acute rejection (AR). The secondary goal was to identify a composite biomarker of CT AR. Clinical details, including a comprehensive clinical examination, and blood samples, enabling analysis of peripheral blood mononuclear cell (PBMC) DNA, RNA and phenotype, were collected from adults with clinically diagnosed AR of FL‐CT (n = 35) and PL‐CT (n = 21) along with Stable CT recipients (n = 177) and adults with non‐transplanted corneal disease (n = 40). For those with AR, additional samples were collected 3 months later. CT acute rejection was clinically diagnosed and defined as precipitates on the corneal graft but not on the peripheral recipient cornea, either scattered or in the form of a Khodadoust line along with an increase in central corneal thickness. Immune cell analysis was performed by whole‐genome microarrays (whole blood) and high dimensional multi‐colour flow cytometry (peripheral blood mononuclear cells). For both, no activation signature was identified within the B cell and T cell repertoire at the time of AR diagnosis. Nonetheless, in FT‐ but not PL‐CT recipients, AR was associated with differences in B cell maturity and regulatory CD4+ T‐cell frequency compared to stable allografts. Our results suggest that, in contrast to solid organ transplants, genetic or cellular assays of peripheral blood are unlikely to be clinically exploitable for prediction or diagnosis of AR. However, further investigation of circulating B cell and T cell subpopulations may provide insights into the regulation of anti‐donor immune response in human CT recipients with differing AR risk.

A 10-Year Retrospective Case Series on Wound Dehiscence Following Corneal Transplant.

Background and objectiveCorneal transplants are associated with multiple well-known complications, one of them being wound dehiscence. It results in unfavorable outcomes, such as ocular structure damage, graft failure, repeated surgeries, and possibly a poor prognosis in terms of vision quality. Although the wound site may appear well-healed clinically, as the strength at the graft-host junction is weak, the site is susceptible to dehiscence. Wound dehiscence can be secondary to suture removal and/or trauma. In this study, we assessed the incidence of wound dehiscence secondary to trauma following corneal transplant and evaluated its occurrence in terms of patient age, type of corneal transplant performed, duration between corneal transplantation and wound dehiscence, mechanism of injury, and final outcome.MethodsThis was a case series that included all patients who suffered from wound dehiscence secondary to trauma post-corneal transplant between January 1, 2009, and December 31, 2019, at Hospital Kuala Lumpur.ResultsA total of 492 patients underwent corneal transplant surgery during the 10-year study period. Based on specified inclusion and exclusion criteria, only 13 patients were eligible for inclusion in this study. The incidence of wound dehiscence secondary to trauma post-penetrating keratoplasty (PK) was low (2.64%). Twelve patients had undergone PK, while one patient had undergone deep anterior lamellar keratoplasty (DALK). Blunt ocular trauma post-transplant can cause wound dehiscence regardless of patient age and duration post-corneal transplantation. Males are at a higher risk as their active lifestyle contributes to higher exposure to ocular injury.ConclusionAs corneal transplant patients are at life-long risk of wound dehiscence post-transplant, they must be counseled about this possible risk and the need to take adequate precautions in their daily lives. Based on our findings, the use of newer technologies and partial- rather than full-thickness corneal transplants should be explored further.

Term Newborn with Corneal Opacity.

Term Newborn with Corneal Opacity.

Environmental Risk Factors Associated With the Need for Penetrating Keratoplasty in Patients With Keratoconus.

PurposeTo identify environmental risk factors associated with the need for penetrating keratoplasty (PKP) (full-thickness corneal transplantation) in patients with keratoconus in a Middle Eastern country.MethodsThis is a retrospective case-control study. This study included patients with keratoconus who underwent PKPor were waitlisted for PKP. Controls were patients diagnosed with keratoconus who did not reach a stage that necessitates PKP. Groups were matched by age and gender. Chi-square test was used to figure out the association between different risk factors including eye rubbing, vernal keratoconjunctivitis (VKC), smoking, paternal consanguinity, eye dryness, family history, asthma, eczema, and diabetes with the need for PKP.ResultsA total of 111 patients were included in this study, there were 48 (43.26%) men and 63 (56.75%) women. The case group included 42 subjects and the control group included 69 subjects. We found statistically significant differences between the two groups in relation to eye rubbing (p=0.0005), VKC (p=0.005), paternal consanguinity (p=0.02), and smoking rate (p=0.04), all being significant in the group in need of PKP. On the other hand, we did not find out a statistically significant difference between the two groups in relation to family history (p=0.31), dryness (p=0.58), asthma (p=0.15), eczema (p=0.28), or diabetes (p=0.29).ConclusionThis study has identified several risk factors associated with the need for PKP in patients with keratoconus, part of which are modifiable. These findings can benefit clinicians in community counseling and give recommendations that can help in preventing or - at least - delaying the need for PKP surgery in keratoconus, such as smoking cessation, aggressive treatment of VKC disease, eye rubbing avoidance, as well as raising awareness regarding the potential risks of paternal consanguinity in this disease entity.

Pythium keratitis: Clinical profile, laboratory diagnosis, treatment, and histopathology features post-treatment at a tertiary eye care center in Eastern India.

Purpose:The aim of this work was to study demography, clinical profile, laboratory diagnosis, and management of Pythium keratitis at a tertiary eye care center in Eastern India.Methods:Eighteen patients with culture-positive Pythium keratitis managed at our center between January 2016 and December 2018 were included in this retrospective study. Clinical features, laboratory investigations, treatment, and outcomes were analysed.Results:Pythium keratitis commonly affects middle-aged males with low socioeconomic profile and history of trauma. Samples stained with Gomori methenamine silver showed 93.8% positivity and Iodine-potassium iodide-sulfuric acid showed 100% positivity. Periodic acid-Schiff's showed negative staining in 62.5% and weak in 37.5%. Kirby-Bauer disc diffusion method showed zone of inhibition as 30.25 ± 4.61 mm for Linezolid and 23.56 ± 6.86 mm for Azithromycin. Medical management included topical/oral linezolid and azithromycin. Therapeutic penetrating keratoplasty (TPK) was done in 15 eyes (83.3%), repeat TPK in 4 eyes, and evisceration in 3 eyes (16.7%). One patient required only medical treatment. Globe salvation was obtained in 15 (83.3%) eyes, and good visual outcome in 7 eyes (38. 9%). There was graft failure in six eyes (40%) and two (11.1%) eyes went into phthisis. Patients were divided into early and late presenters. Late presenters had more complications and worse final visual outcome.Conclusion:Pythium keratitis can be differentiated from fungal keratitis by its characteristic appearance on slit-lamp examination, smear, culture, and histopathology. Early presentation, detection, and treatment with antibacterial drugs like linezolid and azithromycin results in a better prognosis. Early full-thickness corneal transplant should be considered for Pythium keratitis not responding to treatment.

Lamellar Keratoplasty for Advanced Keratoconus.

Ectatic corneal diseases are a group of disorders resulting in progressive corneal steepening and thinning. Keratoconus, keratoglobus, pellucid marginal degeneration, post-keratorefractive ectasia, and corneal graft ectasia are the types of corneal ectasia. Early diagnosis with appropriate diagnostic tools can help prevent progression, eliminating the need for corneal transplantation. Lamellar or full thickness corneal transplantation are the treatment options for advanced diseases. Although the visual outcomes of penetrating keratoplasty are comparable to anterior lamellar keratoplasty (ALK) especially in keratoconus, ALK is the preferred treatment of choice considering benefits including reduced graft rejection, less long-term complications, and better graft survival. This article reviews the various surgical techniques in ALK with its clinical outcomes in advanced keratoconus.

Corneal Endothelial Decompensation.

Endothelial decompensation can occur from a variety of insults to the endothelium that result in loss of stromal clarity. Direct insults to the endothelium commonly occur in inherited, inflammatory, traumatic, immunological, and infectious etiologies. These injuries may cause transient injury without decompensation, but repetitive injury or severe isolated injury can lead to permanent non-compensatory endothelial cell loss. Elevated intraocular pressure can induce stromal hydration, either primarily or secondarily. With partial and full thickness corneal transplants, chronic endothelial dysfunction can be treated surgically when medical therapy proves inadequate. Practitioners should be aware of the underlying causes for corneal endothelial injury.

Approaches toward enhancing survival probability following deep anterior lamellar keratoplasty.

The greatest advantage of deep anterior lamellar keratoplasty over full-thickness corneal transplantation is the elimination of graft failure caused by endothelial rejection. Despite this advantage, a deep anterior lamellar keratoplasty graft can fail because of several factors, such as complications related to the donor–recipient interface, graft epithelial abnormalities, graft vascularization, stromal graft rejection, and recurrence of herpetic keratitis. Increased deep anterior lamellar keratoplasty graft survival is mainly built upon optimization of the ocular surface to provide a hospitable environment for the graft. Any predisposing factors for graft epithelial abnormalities, corneal neovascularization, and preexisting vernal keratoconjunctivitis should be identified and treated preoperatively. Prompt recognition and appropriate treatment of interface-related complications and stromal graft rejection usually result in good anatomic outcomes, with no detrimental effects on vision.

A case of in vivo iontophoresis-assisted corneal collagen cross-linking for keratoconus: An immunohistochemical study

The standard corneal collagen cross-linking (CXL), that includes the removal of corneal epithelium to permit adequate penetration of riboflavin in the stroma, is an established procedure to halting keratoconus progression. However, as epithelial removal may cause postoperative pain and an increased risk of corneal infection, new therapeutic approaches have been proposed. Iontophoresis is a recently developed non-invasive technique which provides the use of electrical current during CXL to enhance transepithelial penetration of riboflavin into the corneal stroma. Here, we describe for the first time the morphological changes of the corneal stromal compartment in a patient with keratoconus who underwent in vivo iontophoresis-assisted CXL (ionto-CXL) before full-thickness corneal transplantation. Immunohistochemistry for type I collagen and CD34 was performed to investigate the stromal distribution of collagen fibers and keratocytes, respectively. The histology of ionto-CXL-treated keratoconic cornea, collected 6 months after the intervention, was compared with that of healthy corneas and either untreated or standard CXL-treated keratoconic corneas. An attempt to restore a normal stromal architecture was observed in the ionto-CXL-treated cornea compared with untreated keratoconic corneas. In particular, the ionto-CXL-treated cornea showed a parallel distribution of type I collagen fibers, although fiber interweaving appeared less organized than in healthy corneas and standard CXL-treated keratoconic corneas. Moreover, the distribution of CD34-positive keratocytes was improved in keratoconic corneas following ionto-CXL treatment, though a scattered CD34 immunoreactivity was still noticeable in the subepithelial stroma. This study provides histological evidence that ionto-CXL may represent a non-invasive alternative in the management of progressive keratoconus in adults.

Suppression of Allograft Rejection with Soluble VEGF Receptor 2 Chimeric Protein in a Mouse Model of Corneal Transplantation

When a transparent cornea becomes opaque due to infectious diseases, trauma, or ophthalmic surgery, the impaired cornea is replaced with a donor cornea to improve visual function. In this corneal transplantation, the graft survival rate is comparatively high, partly because of lacking vascular and lymphatic vessel in cornea. However, the transplanted corneas sometimes become opaque if allograft rejection occurs. Suppression of allograft rejection is critical for favorable outcomes of corneal transplantation. The essential effects of endogenous monomeric soluble vascular endothelial growth factor receptors (VEGFRs) 1 and 2 have been reported in corneal angiogenesis and lymphangiogenesis. This study investigated the effects of dimeric soluble VEGFR2/Fc chimera protein on corneal allograft rejection for future clinical application. Allogeneic full-thickness corneal transplantation was performed in C57BL/6 to BALB/c mice. The recipients were treated by intrastromal injection of soluble VEGFR1/Fc chimera (sR1/Fc group), soluble VEGFR2/Fc chimera (sR2/Fc group), or human IgG1/Fc protein (IgG/Fc group) at 0, 7, and 14 days after surgery. Both hemangiogenesis and lymphangiogenesis were significantly suppressed in the corneas of the sR2/Fc group compared with the IgG/Fc group. All grafts failed due to corneal wound rupture in the sR1/Fc group. In the sR2/Fc group, respective donor-derived MHC class II(+)/CD11c(+) cells and CD11b-positive macrophage infiltration were reduced in the DLNs and the corneas showing a negative delayed-type hypersensitivity, compared with the IgG/Fc group. Our findings demonstrate that soluble VEGFR2/Fc chimera protein efficiently suppresses corneal allo-rejection, while reducing hemangiogenesis and lymhangiogenesis, and immune-competent cell-trafficking and may be a powerful tool for corneal allograft survival.

The roles of sepsis-induced myeloid derived suppressor cells in mice corneal, skin and combined transplantation

PurposeTo explore the effects of adoptive transferring sepsis induced myeloid-derived suppressor cells (iMDSCs) in mice corneal, skin, and combined corneal–skin survival. MethodsAllogeneic full-thickness corneal transplantation, fully mismatched skin transplantation, and corneal–skin combined transplantation (donor C57BL/6 to recipient Balb/c mice) were performed. Sepsis-induced infectious-MDSCs (iMDSCs), were purified from bone marrow of cecal ligated and punctured (CLP) Balb/c mice. Recipient-derived iMDSCs were adoptively transferred into different recipient groups by retro-orbital injection after surgeries. Corneal and skin grafts were examined and photographed routinely for a period of 45days. Histopathology was performed to evaluate corneal-graft inflammation. Bone marrow and/or corneal grafts in each group were harvested from executed recipients on postoperative days 15, 25, 35. Corneal cells and bone marrow cells were stained with CD11b-PE and Gr1-FITC, analyzed by FACS. ResultsiMDSCs were able to significantly prolong allograft survival in both corneal and corneal–skin combined transplant groups. A substantial expansion of MDSCs was observed in recipients' bone marrow, particularly in combined groups at an early stage postoperatively, and accordingly the concentration of MDSCs in corneal grafts increased significantly in adoptive transferred groups. ConclusionsSepsis-induced MDSCs may suggest a novel cellular therapeutic approach for preventing various types of allograft rejection.

Effects of Adoptive Transferring Different Sources of Myeloid-Derived Suppressor Cells in Mice Corneal Transplant Survival.

Adoptively transferring different sources of myeloid-derived suppressor cells (MDSCs) may assist in mice corneal transplant survival. Allogeneic full thickness corneal transplantation (donor C57BL/6 to recipient Balb/c mice) was performed. Naive myeloid cells, inflammation-induced MDSCs (iMDSCs), and tumor-induced MDSCs (tMDSCs) were purified from bone marrow of naive, cecal ligation and puncture, or tumor-bearing Balb/c mice, respectively. The inhibitory abilities of myeloid cells toward CD4(+) T cell proliferation were accessed by in vitro carboxyfluorescein diacetate, succinimidyl ester (CFSE) assays. Myeloid cells were adoptively transferred to corneal recipients by retroorbital injection after corneal transplantation. Corneal grafts were examined and photographed for a period of 45 days. The growth of corneal graft neovascularization was quantitatively measured by image editing software. Histopathology was performed to evaluate corneal graft inflammation. The iMDSCs and tMDSCs significantly inhibited T cell proliferation in vitro and significantly prolonged corneal allograft survival in vivo. Strikingly, iMDSC transferring significantly reduced neovascularization that was comparable to transferring of tMDSCs, without additional immunosuppression. However, additional adoptive transfer of MDSCs did not further ameliorate corneal survival in these allogeneic corneal transplantation mice. Inflammation-induced MDSC transfer could reduce corneal neovascularization and prolong corneal allograft survival.

Construction of corneal epithelium with human amniotic epithelial cells and repair of limbal deficiency in rabbit models.

This study aims to evaluate the effect of a human amniotic epithelial cell (HAEC)-rabbit corneal stroma tissue-engineered cornea on ocular reconstruction in three different animal models. HAECs were isolated from human placenta, seeded onto rabbit corneal stroma. HAECs-rabbit corneal stroma tissue engineering cornea transplantation was examined in three distinct rabbit models: transplantation of cornea constructed (1) with lamellar corneal HAECs and rabbit corneal stroma, (2) with central corneal HAECs and rabbit corneal stroma, or (3) with full-thickness corneal HAECs and rabbit corneal stroma. In the tissue engineering corneal transplantation groups in all three models, the mean number of days to corneal epithelial healing was significantly shorter than that in the control group and the mean number of days to corneal neovascularization was significantly greater than in the control group. In addition, in the tissue engineering corneal transplantation groups in the central lamellar cornea model and the full-thickness corneal transplantation model neovascularization, corneal turbidity, and epithelial fluorescence were significantly less than in the control groups. HAECs can be induced to differentiate into corneal epithelial cells, which may be suitable for the reconstruction of the corneal epithelium in cases of limbal stem cell deficiency.

Functional Tumor Necrosis Factor Alpha Polymorphisms and Haplotype Analysis in High-Risk Corneal Transplantation

BackgroundTumor necrosis factor alpha (TNF-α) plays a critical role in diverse cellular processes including ocular immune tolerance, inflammation, and allograft rejection. The ubiquitous transcription factor nuclear factor kappa B (NF-κB) regulates expression of numerous genes. Induction of the TNF-α pathway is involved in the inflammatory response and loss of transplant tolerance. ObjectivesWe investigated functional single nucleotide polymorphisms (SNPs) in the promoter region of TNF-α and an insertion/deletion (indel) polymorphism of NF-κB1 in corneal transplant recipients considered to be at increased risk of immunological rejection (ie, high-risk corneal transplantations) and looked for any associations with corneal transplantation outcome. Patients and MethodsThree hundred eighty-four full thickness corneal transplant recipients were followed for 3 years and episodes of reversible and irreversible allograft rejection were recorded. Using DNA obtained from these patients, 5 SNPs located in the promoter region −1031 T/C rs1799964, −863 C/A (rs1800630), −857 C/T (rs1799724), −308 G/A (rs1800629), and −238 G/A (rs361525), and one SNP upstream from the transcription start site (+489) rs1800610 of TNF-α were analyzed using induced heteroduplex generation. A functional NF-κB1 indel (−94) was also investigated. Haplotypes were inferred by PHASE and associations with rejection were determined by chi-square analysis. ResultsThe TNF-α haplotype TCTGGA was significantly associated with reduced risk of corneal graft rejection (Pc < .005) and TCTAGA was associated with increased risk of rejection (Pc < .005) in high-risk corneal transplants. There was no association with the NF-κB1 indel (Pc > .05). ConclusionAccording to haplotype frequencies, our results suggest that the TCTGGA haplotype may confer additional protection against risk of immunological rejection whereas TCTAGA may increase risk of corneal allograft rejection in the high-risk setting. However, both haplotypes were relatively rare and thus would not warrant genotyping for individual patient selection for anti-TNF therapy.