Single-cell RNA sequencing in cornea research: Insights into limbal stem cells and their niche regulation.

The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye, which acts as a protective barrier and is critical for clear and stable vision. Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells (LSCs), a cell population that resides at the limbus in a highly regulated niche. Dysfunction of LSCs or their niche can cause limbal stem cell deficiency, a disease that is manifested by failed epithelial wound healing or even blindness. Nevertheless, compared to stem cells in other tissues, little is known about the LSCs and their niche. With the advent of single-cell RNA sequencing, our understanding of LSC characteristics and their microenvironment has grown considerably. In this review, we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology, including the heterogeneity of the LSC population, novel LSC markers and regulation of the LSC niche, which will provide a reference for clinical issues such as corneal epithelial wound healing, ocular surface reconstruction and interventions for related diseases.

Should ocular Demodex be checked and treated in refractory keratitis patients without blepharitis?

AIM: To evaluate the correlation between Demodex infestation and keratitis, and to assess demodicosis using a simple approach. METHODS: A modified slit lamp illumination (at 40× magnification) was used to observe Demodex tails in 40 patients with refractory keratitis and 80 healthy controls. Bacterial smear and culture of the conjunctival sac and corneal lesion were performed to identify the pathogen. Tea tree oil ointment (TTOO) was added as a Demodex killing agent for lid scrubs to the treatment when Demodex infestation was confirmed. RESULTS: Demodex tails were found in all patients compared to 42/80 of the controls (P<0.01). Seventeen patients presented blepharitis, while 23 were free of scales and inflammation at the lid margin. The demodicosis was mild, moderate, and severe in 8, 19, and 13 patients, respectively, compared to mild in 42 controls (P<0.01). The keratitis was mild, moderate, and severe in 13, 19, and 8 patients, respectively. The severity of Demodex infestation was not correlated to the severity of keratitis (P=0.126). The growth of Staphylococcus was revealed in nine patients who did not react to antibiotic eye drops prior to the TTOO treatment. Patients' signs and symptoms got resolved after the lid scrub with TTOO. CONCLUSION: Ocular Demodex needs to be checked and treated in refractory keratitis patients with or without blepharitis. A slit-lamp illumination under high magnification favors the judgment of the severity of Demodex infestation.

Multi-level consistent changes of the ECM pathway identified in a typical keratoconus twin's family by multi-omics analysis.

BACKGROUND: Keratoconus (KC) is a common, degenerative disorder of the cornea, and genetic factors play a key role in its development. However, the genetic etiology of KC is still unclear. This study used the family of twins as material, using, for the first time, multi-omics analysis, to systematically display the changes in KC candidate factors in patients at the DNA, RNA, and protein levels. These can evaluate candidate pathogenic factors in depth and lock onto pathogenic targets. RESULTS: The twins in this study presented classic phenotypes, clear diagnoses, complete case data, and clinical samples, which are excellent materials for genetically studying KC. Whole-exome sequencing was conducted on both the twins and their parents. Transcriptome sequencing was conducted on proband's and health individual's primary human corneal fibroblast cells. Quantitative Real-time PCR and western blot were used to validate the differential gene expressions between the proband and controls. By integrating genomics, transcriptome, and protein level data, multiple consecutive events of KC were systematically analyzed to help better understand the molecular mechanism and genetic basis of KC. The results showed that the accumulation of rare, micro-effect risk variants was the pathogenic factor in this Chinese KC family. Consistent changes in extracellular matrices (ECMs) at the DNA and RNA levels suggested that ECM related changes play a key role in KC pathogenesis. The major gene variants (WNT16, CD248, COL6A2, COL4A3 and ADAMTS3) may affect the expression of related collagens or ECM proteins, thus reducing the amount of ECM in corneas and resulting in KC. CONCLUSIONS: This study, the first to explore the genetic etiology of KC via multi-omics analysis under the polygenetic model, has provided new insights into the genetic mechanisms underlying KC and an effective strategy for studying KC pathogenesis in the future.

Increased succinate receptor GPR91 involved in the pathogenesis of Mooren's ulcer.

AIM: To investigate the expression of succinate receptor GPR91 and its pathogenic roles in Mooren's ulcer (MU). METHODS: Biopsy specimens were obtained from 7 patients with MU and 6 healthy donors. The expression of GPR91 in MU tissues was evaluated using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). Succinate was used to activate GPR91 signaling, and the effect of GPR91 on the expression of interleukin-1ß (IL-1ß), NLRP3, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-13 (MMP-13) in human peripheral blood mononuclear cells (PBMCs) was determined. The influence of GPR91 on the nuclear factor-κB (NF-κB) signaling in PBMCs was investigated by detecting the phosphorylation of p65. Moreover, the expression of IL-1ß, VEGF, MMP-13 and phosphorylated p65 (p-p65) in the tissues of MU was examined by qRT-PCR or IHC. RESULTS: GPR91 mRNA expression showed a higher level in the MU group than in the healthy control group. IHC analysis also revealed that the expression of GPR91 was elevated in patients with MU compared with healthy controls. Moreover, ligation of GPR91 with succinate promoted the lipopolysaccharide-induced production of NLRP3, IL-1ß, VEGF and MMP-13 in PBMCs through increased phosphorylation of p65. Pharmacological inhibition of the NF-κB signaling reversed GPR91 induced production of NLRP3, IL-1ß, VEGF and MMP-13. These findings, coupled with the elevated amounts of IL-1ß, VEGF, MMP-13 and p-p65 observed in the MU biopsies, constituted a rational basis for the involvement of GPR91 in the pathogenesis of MU. CONCLUSION: This study indicates the increased succinate receptor GPR91 in conjunctival or corneal tissues is involved in the pathogenesis of MU through elevated NF-κB activity, which may provide a new therapeutic target for MU.

De novo mutations of TUBA3D are associated with keratoconus.

Keratoconus (KC) is a common degenerative corneal disease, and heredity plays a key role in its development. Although few genes are known to cause KC, a large proportion of disease-causing genes remain to be revealed. Here, we report the identification of TUBA3D as a novel gene linked to KC. Using whole-exome sequencing of a twins pedigree, a novel de novo mutation (c.31 C > T, p.Gln11stop) in TUBA3D gene was identified. A screening performed in 200 additional unrelated patients with KC revealed another two mutations (c.201insTT, p.Val68Leufs*2; c.*2 G > A) in two patients. TUBA3D was expressed highly in the cornea, and the twins had lower TUBA3D expression and higher UPA and MMP1 expressions than the normal parents. Through function prediction and in vitro cell experiment, we further demonstrated that the mutant proteins of TUBA3D were unstable and could lead to human corneal fibroblast cells performing higher MMPs expression and oxidative stress. These changes thus reduce the amount of extracellular matrices within corneas and undoubtedly play a major role in stromal thinning, which is characteristic of KC corneas. Our study showed that TUBA3D is a new gene that causes KC, thus supporting the evidence that this protein has an additional function into the human cornea.

In situ cornea harvesting through the Red Cross Organization: a new approach to relieving severe cornea donor shortage in Chinese eye banks.

Corneal diseases are currently the second main cause of blindness in China. Although most of the corneal blindness could be treated by corneal transplantation, only about 10 000 operations were carried out each year owing to the severe shortage of corneal donors and limited eye bank programs. A feasible cornea donation program was established through the organization of the Red Cross, and in situ corneal removal techniques were developed to avoid conflicts with Chinese traditions of keeping the deceased intact. The number of donated corneas, which had a safe and secure quality, increased significantly year by year.

Changes of meibomian glands in patients with type 2 diabetes mellitus.

AIM: To investigate the morphological changes of meibomian glands in patients with type 2 diabetes mellitus (DM). METHODS: Of 118 eyes (118 patients) with type 2 DM (DM group) and 100 eyes of 100 control subjects (control group) were enrolled. After completing an ocular surface disease index (OSDI) questionnaire, the non-invasive tear film break-up time (NI-BUT) and the structure of the meibomian glands (MGs, meibography) were assessed by the Keratograph 5M system. Partial or complete loss of MG was scored for each eyelid from grade 0 (no loss) to grade 3 (lost area was >2/3 of the total MG area), which were also examined by laser scanning confocal microscopy (LSCM). The primary outcomes were meibomian gland acinar unit density (MGAUD), meibomian gland acinar longest diameter (MGALD) and meibomian gland acinar shortest diameter (MGASD). RESULTS: Compared with control group, the OSDI was significantly higher in DM group (Z=-5.916; P<0.001), while the NI-BUT was significantly lower (Z=-7.765; P<0.001). Keratograph showed that there were more MGs dropout in DM group than that in control group. The meiboscore was significantly higher in DM group compared with control group (Z=-3.937; P<0.001). LSCM revealed that there were cytological alterations of MGs in DM group compared with control group, which included enlargement of MG acinar units and decreased in density of MG acinar units. Specifically, there were lower MGAUD, larger MGALD and MGASD in DM group than control group (Z=-10.120, -9.4442, -7.771; P<0.001). CONCLUSION: Compared with the normal control participants, the patients with type 2 DM had more unstable tear films and severe symptoms of dry eye. Using Keratograph 5M system and LSCM, we found that the patients with type 2 DM had more significant morphological and cytological changes and dysfunction in MGs.

Preoperative evaluation and outcome of corneal transplantation for limbal dermoids: a ten-year follow-up study.

AIM: To summarize preoperative evaluation and outcome of corneal transplantation for limbal dermoids for ten years. METHODS: Eighty-five patients diagnosed with limbal dermoids and treated with corneal transplantation were analyzed retrospectively. All patients were further divided into two groups according to absence or presence of neovascularization surrounding the dermoids in the corneal stroma. Eighty-two eyes were treated with tumor excision combined with partial lamellar sclerokeratoplasty, and the other three eyes were performed by penetrating keratoplasty. The size and location of the tumor, the associated ocular and systemic anomalies, the depth of the corneal penetration of tumor tissues, the preoperative and postoperative best-corrected visual acuity (BCVA), graft survival and cosmetic outcome, and surgical complications were recorded respectively. RESULTS: The average age at surgery was 5.3y (range, 3mo-36y). The mean size of dermoids was 6.1±1.6 mm. The 43.5% of eyes (37/85) were present with hair at the surface of the dermoid and 72.9% of dermoids were located inferotemporal of the eye. Amplyopia was present in 34.1% of patients (29/85) and 9.4% of patients (8/85) had lipodermoids. Eighteen patients suffered from Goldenhar's syndrome with an accessory ear. The 75% of patients in group 1 had involvement of the corneal deep stroma down to Descemet's membrane without involving it, but 71.4% of patients had Descemet's membrane involvement in group 2. Preoperative BCVA ranged from counting fingers to 20/20. Postoperatively 81.1% had a BCVA of 20/800 or better. There was no significant difference between the post-surgical BCVA of the two groups (t=1.584, P>0.05). The grafts of 70.5% patients were present as 1+ opacity, 21.1% as 2+ opacity, 8.2% as 3+ opacity and none as 4+ opacity. Surgical complications included graft rejection, microperforation, prolonged reepithelialization, steroid glaucoma, interface neovascularization, and interface hemorrhage. CONCLUSION: The dermoids with neovascularization surrounding them in the corneal stroma invaded deeper tissues in the cornea than those with no neovascularization surrounding them in the corneal stroma. Therefore, surgeons should take care to avoid corneal perforation during the corneal transplantation operation. The majority of patients markedly improved their cosmetic appearance after surgery.

TGF-ß and NF-κB signaling pathway crosstalk potentiates corneal epithelial senescence through an RNA stress response.

The corneal epithelium plays important roles in the maintenance of corneal transparency for good vision, and acts as a protective barrier against foreign insults. Structural and functional changes with aging in the corneal epithelium have been documented. Here we found that transforming growth factor-ß (TGF-ß) is highly expressed in the elderly donor corneal epithelium, as are senescence-associated genes, such as p16 and p21. In human corneal epithelial cell (HCEC) models, TGF-ß induces cellular senescence, characterized by increased SA-ß-gal positive cells and elevated expression of p16 and p21. Pharmacological inhibition of TGF-ß signaling alleviates TGF-ß-induced cellular senescence. In addition, we determined that senescence-associated inflammation was significantly aggravated in TGF-ß-induced cellular senescence by detecting the expression of interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNFα). Both genetic and pharmacological approaches revealed that blocking nuclear factor-κB (NF-κB) signaling not only inhibited the production of inflammatory factors, but also rescued the senescent phenotype induced by TGF-ß in HCECs. Mechanistically, TGF-ß induced an atypical RNA stress responses, leading to accelerated mRNA degradation of IκBα, an inhibitor of NF-κB. Together, our data indicate that TGF-ß-driven NF-κB activation contributes to corneal epithelial senescence via RNA metabolism and the inflammation blockade can attenuate TGF-ß-induced senescence.

Bevacizumab modulates retinal pigment epithelial-to-mesenchymal transition via regulating Notch signaling.

AIM: To investigate the effect of bevacizumab treatment on Notch signaling and the induction of epithelial-of-mesenchymal transition (EMT) in human retinal pigment epithelial cells (ARPE-19) in vitro. METHODS: In vitro cultivated ARPE-19 cells were treated with 0.25 mg/mL bevacizumab for 12, 24, and 48h. Cell morphology changes were observed under an inverted microscope. The expression of zonula occludens-1 (ZO-1), vimentin and Notch-1 intracellular domain (NICD) was examined by immunofluorescence. The mRNA levels of ZO-1, α-SMA, Notch-1, Notch-2, Notch-4, Dll4, Jagged-1, RBP-Jk and Hes-1 expression were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of α-SMA, NICD, Hes-1 and Dll-4 expression were examined with Western blot. RESULTS: Bevacizumab stimulation increased the expression of α-SMA and vimentin in ARPE-19 cells which changed into spindle-shaped fibroblast-like cells. Meanwhile, the mRNA expression of Hes-1 increased and the protein expression of Hes-1 and NICD also increased, which Notch signaling was activated. The mRNA expression of Notch-1, Jagged-1 and RBP-Jk increased at 48h, and while Dll4 mRNA and protein expression did not change after bevacizumab treatment. CONCLUSION: Jagged-1/Notch-1 signaling may play a critical role in bevacizumab-induced EMT in ARPE-19 cells, which provides a novel insight into the pathogenesis of intravitreal bevacizumab-associated complication.

[Several problems of diagnosis and treatment in fungal keratitis in China].

Fungal keratitis is one of major blindness disease in corneal infection. At present, mistake and missed diagnosis were often happened in Fungal keratitis. Initial doctor was insufficient knowledge of diagnosis. There were not to do etiology examination in corneal fungal infection, and lead to some case getting worse during medicinal treated. Highly ratio patients need controlled infection by corneal transplantation due to severe lack antifungal eye drops, and poor understood the way of antifungal medicine in clinic. Finally, Fungal keratitis is still one of major intractable disease in corneal infection, because some doctor were short of experience to hold surgical opportunity and indication, and corneal donor severe shortage in China.

[Mitomycin C related complications shouldn't be neglected in the pterygium surgery].

Mitomycin C (MMC), as it could reduce tissue adhesions and scar formation, has been widely adopted in pterygium surgery to lower the recurrence rate.Upon a certain therapeutic effect obtained, a variety of ocular complications was combined and always occupies a quite long time after MMC application.once occurred, it was tough to cure. Compared to autologous limbal-conjunctival grafts, MMC has no apparent advantage to reduce reoccurrence of pterygium. Therefore, it is advised to abandon the use of MMC in pterygium surgery.

[Preliminary clinical results of deep anterior lamellar keratoplasty in the treatment deep infectious purulent keratitis].

OBJECTIVE: To evaluate the clinical results of deep anterior lamellar keratoplasty (DALK) assisted by big bubble technique in the treatment of deep infectious purulent keratitis. METHODS: Seventeen patients (17 eyes) with deep infectious purulent keratitis received DALK surgery in Shandong Eye Hospital from January 2011 to March 2012. Case selection:Patients with purulent keratitis, the infection or infiltrate depth was more than four fifth corneal thickness; SURGICAL TECHNIQUE: Use DALK assisted by big bubble technique to cut off the lesions and expose the Descemet's membrane. The prepared donor which stored in D-X medium or in glycerine preoperatively was oversized by 0.25 mm, and after stripping of Descemet's membrane, the donor button was interrupted sutured with 10-0 nylon suture. The perioperative complications, recurrence, graft status and visual recovery were evaluated. RESULTS: The mean follow up time were 9 months.17 patients with average age of (46 ± 13) year old received DALK surgery, including 14 cases of fungal keratitis and 3 cases of bacteria keratitis. Perioperative complications:Two cases suffered micro perforation and were continuing performed DALK surgery after injecting air bubble in the anterior chamber. Three cases suffered double anterior chamber, one was resolved after graft resuture, and the other two were absorbed automatically.One patient suffered fungal recurrence and cured with secondary penetrating keratoplasty. Graft status:All grafts attached closely to the recipients, slit lamp and AS-OCT examinations were difficult to distinguish the interface. All of grafts were transparent. Visual acuity:before the operation best corrected visual acuity (BCVA) in patients with HM/20 cm to 3.7, after the surgery patients' BSCVA improved to 4.5-5.0. The mean astigmatism postoperatively of 16 cases received successful DALK finally was (4.53 ± 2.35) D . CONCLUSIONS: For patients with deep infectious purulent keratitis, big bubble technique assistants DALK surgery is still a safe and effective method.

Clinical observation of removal of the necrotic corneal tissue combined with conjunctival flap covering surgery under the guidance of the AS-OCT in treatment of fungal keratitis.

AIM: To study the clinical observation of removal of the necrotic corneal tissue combined with conjunctival flap covering surgery under the guidance of the AS-OCT in treatment of fungal keratitis. METHODS: A retrospective study was done to 10 patients (10 eyes) who had accepted removal of the necrotic corneal tissue combined with conjunctival flap covering surgery for fungal keratitis,the diagnosis by corneal scraping and smear examination or confocal microscopy check hyphae.Local and systemic antifungal therapy more than one week for all patients, corneal ulcer enlarge or no shrink.Slit lamp microscope examination the diameter of corneal ulcer about 2mm-4mm.Anterior segment optical coherence tomography (AS-OCT) examine the depth of corneal ulcer between 1/3-1/2,infiltrate corneal stroma about 20um-80um,the diameter of corneal ulcer about 3mm-6mm.Type-B ultrasonic exclusion endophthalmitis. Complete removal lesions until transparent of stroma, make conjunctival flap equal or greater than ulcer 1mm nearby conjunctiva. Continued antifungal therapy. The vision, fungal recurrence, conjunctival flap rollback or desquamate were analysed. RESULTS: Ten patients had success done this surgery, the corneal ulcer was not enlarge and healing afteroperation.7 cases were bridging conjunctival flap and 3cases were single conjunctival flap. Preoperation vision above 0.1 had 8 cases,7 cases had vision above 0.1 one week after surgery, while 1 cases vision droped from 0.3 to 0.05.There was not recurrent for fungal,2 cases conjunctival flap rollback:1 case was bridging and 1case was single flap, no conjunctival flap desquamate. CONCLUSION: It is safe and effective to perform removal of the necrotic corneal tissue combined with conjunctival flap covering surgery under the guidance of the AS-OCT in treatment of fungal keratitis which werenot sensitive or aggravate for antifungal drugs.

Lymphocyte infiltration and activation in iris-ciliary body and anterior chamber of mice in corneal allograft rejection.

AIM: To investigate the infiltration and activation of lymphocyte in iris-ciliary body and anterior chamber after allogenic penetrating keratoplasty (PK), for further revealing the role of iris-ciliary body in corneal allograft immune rejection. METHODS: In the mice models of PK, BALB/C mice received orthotopic isografts (n =35) or C57BL/6 donor allografts (n =25). Grafts were examined daily for 3 weeks by slit-lamp microscopy and scored for opacity. The infiltration of CD4(+) T lymphocyte in iris-ciliary body and anterior chamber was examined by immunohistology and the mRNA of CD80 and CD86 in both cornea graft and iris-ciliary body by RT-PCR was analyzed in allograft recipient at days 3, 6, 10 and the day when graft rejection occurred. Isograft recipients were examined as control at the corresponding time points. Transmission electron microscope was used to study the ultrastructure, especially cell infiltration, of iris-cilary body and corneal graft at day 3, 7 and the day when rejection occurred after allogenic PK. RESULTS: Rejection was observed in all the allograft recipients followed more than 10 days, at a median time of 15 days (range 12-18 days), but not in any of isografts. CD4(+) T cells were first detected at day 6 after transplantation in limbus and Ciliary body, and then in the stroma of recipient, iris, anterior chamber and corneal allograft with an increased number until graft rejection occurred. CD80 and CD86 mRNA were detected under RT-PCR examination in both graft and iris-ciliary body of allograft recipient, but not in any of isograft recipient. Three days after operation, lymphocytes and monocytes macrophages were visible in iris blood vessels and the anterior chamber, and vascular endothelial cell proliferation and activation were significant under transmission electron microscopy examination. At day 7, corneal endothelial cells became thinner. Lymphocytes and mononuclear macrophages were found with great number in the anterior chamber and adhered to the corneal endothelium. Blood vessels in iris increased and were filled with lymphocytes. And lymphocytes were detected to migrate through endothelial cell gap out of vessels. When allograft rejection occurred, macrophages attached to endothelial cells with large number of lymphocytes and macrophages infiltrating in iris. CONCLUSION: Lymphocyte infiltration and activation occurred in iris-ciliary body after allogenic PK, and the lymphocytes could migrate from iris blood vessel to the anterior chamber, which might play an important role in corneal allograft immune rejection.

[Strengthen the study of several issues on diagnosis and treatment of the corneal herpetic endotheliitis].

Herpes simplex keratitis (HSK), including epithelial keratitis, stromal keratitis, and endotheliitis, is one of the major blinding eye diseases in China. Corneal herpetic endotheliitis has a variety of clinical manifestations, which causes much difficulty for diagnosis and treatment. This paper suggests a uniform classification of corneal herpetic endotheliitis, which helps to the set up and wide application of a standard treatment protocol. As a result, the cure rate would be increased significantly, corneal endothelium loss due to misdiagnosis would be reduced, and finally the blindness rate of HSK would be lowered.

[The preliminary study of establishing animal model of chronic allograft dysfunction after penetrating keratoplasty].

OBJECTIVE: To establish a murine model of chronic corneal allograft dysfunction (CCAD) after penetrating keratoplasty (PK). METHODS: Experimental study. PK model in mice: Semiallogeneic CB6F1 mice were obtained from matching of female BALB/c and male C57BL/6 mice. C57BL/6 (allogeneic group), CB6F1 (semiallogeneic group) and BALB/c (syngeneic group) grafts were transplanted orthotopically to BALB/c recipients respectively, and BALB/c mice as a control group. The follow-up time was more than 100 d, and graft survival time and corneal opacity score were monitored, and corneal endothelium were examined by alizarin red and PI/Hoechst stain. CD4(+) and CD8(+) T lymphocytes were examined by immunohistochemistry. Ultrastructure changes of the grafts were examined by electronmicroscopy. Log-rank test were used to compare survival curves. RESULTS: (1) Graft examination:Median graft survival times were 17.0 d, 85.5 d, > 100 d and > 100 d in allogeneic, semiallogeneic, syngeneic and control groups, respectively (F = 344.0, P < 0.01). (2) Immunohistochemistry examination: There were large amount of CD4(+) and CD8(+) T lymphocyte infiltration in allografts in allogeneic group at 3 weeks after PK; Few CD4(+) and CD8(+) T lymphocytes were observed in semiallogeneic group and syngeneic groups at 3 weeks after PK; CD4(+) and CD8(+) T lymphocyte infiltration was not observed in the control group. (3) Endothelium examination: The endothelium can not be counted because the blurred image after the alizarin red combined PI/Hoechst stain and apoptotic and necrotic cells can be seen in allogeneic group; the endothelial cell density decreased and few apoptosis can be detected in semiallogeneic and syngeneic groups; no apoptotic and necrotic endothelial cells were found in the control group. (4) Ultrastructural characteristic changes mainly include fibrosis formation and endothelium atrophy and degeneration in failed grafts in all transplanted groups by electron microscopy examination. Inflammation cells can only be found in the allogeneic group. CONCLUSIONS: Semiallogeneic and syngeneic transplantation groups present the changes similar to CCAD in clinical study, and both can be regarded as the model that permits molecular evaluation of CCAD.

The biological characteristics and pharmacodynamics of a mycophenolate mofetil nanosuspension ophthalmic delivery system in rabbits.

The purpose of this study was to investigate corneal mucoadhesion, pharmacokinetics in lacrimal fluid and aqueous humor, the immune suppression induced by corneal transplantation of mycophenolate mofetil (MMF) nanosuspensions (NS), and the use of a chitosan-modified MMF nanosuspension (C-NS) as an ophthalmic delivery system. The results indicated that NS had a higher drug concentration in corneal muscoadhesive samples, lacrimal fluid and aqueous humor samples than the MMF ophthalmic suspension. In addition, C-NS had a much higher concentration than the NS. The mean survival time of cornea in corneal allografts was extended remarkably in the NS and C-NS trial groups. The results confirm that the C-NS and NS markedly increase corneal mucoadhesion and drug absorption, prolong the survival time of high-risk allografts, and significantly inhibit corneal immune rejection in a rabbit model of penetrating keratoplasty. In this model, C-NS was more effective than NS.

[Clinical application of irrigation in therapeutic keratoplasty for suppurative keratitis with severe hypopyon].

OBJECTIVE: To investigate the safety and clinical efficacy of anterior chamber irrigation combined with corneal transplantation in the treatment of corneal ulcer with severe hypopyon. METHODS: Non-randomized retrospective case series. Twenty patients (20 eyes) suffered from corneal ulcer with severe hypopyon were enrolled in Shandong Eye Hospital from January 2008 to June 2009, and 13 patients with significant corneal endothelial plaque, which hard to determine the lesion edge under microscope. Twenty patients received anterior chamber irrigation combined with penetrating or lamellar keratoplasty treatment; the donors were preserved in the medium-term preservation solution or freeze-dry preservation of glycerine. Intraoperative and postoperative complications, visual acuity, immune rejection were collected as outcome measures. RESULTS: Twenty cases received anterior chamber irrigation combined with corneal transplantation successfully, eleven of which received penetrating keratoplasty (PK) and 9 received lamellar keratoplasty (LK). Ten cases that underwent PK using donors preserved in medium-term solution, and the remaining using donors cryopreserved at -20 degrees C. Intraoperative complications include bleeding iris (11 cases), postoperative complications including iris adhesions (8 cases), transient high intraocular pressure (4 cases), anterior chamber hemorrhage (5 cases), and were cured after drug treatment. One case suffered recurrence of fungal keratitis and received repeat PK. Four cases occurred endothelial immune rejection, 3 cases were controlled and 1 case occurred graft failure after anti-rejection treatment. In the final follow-up in December 2009, 17 grafts were clear and 3 grafts were edema. CONCLUSION: In the treatment of severe corneal ulcer with hypopyon, anterior chamber irrigation combined with penetrating or lamellar keratoplasty is an effective and a safety method.