Mesenchymal stem cells: Potential role in corneal wound repair and transplantation

Corneal diseases are a major cause of blindness in the world. Although great progress has been achieved in the treatment of corneal diseases, wound healing after severe corneal damage and immunosuppressive therapy after corneal transplantation remain prob-lematic. Mesenchymal stem cells(MSCs) derived from bone marrow or other adult tissues can differentiate into various types of mesenchymal lineages, such as osteocytes, adipocytes, and chondrocytes, both in vivo and in vitro. These cells can further differentiate into specific cell types under specific conditions. MSCs migrate to injury sites and promote wound healing by secreting anti-inflammatory and growth factors. In ad-dition, MSCs interact with innate and acquired immune cells and modulate the immune response through their powerful paracrine function. Over the last decade, MSCs have drawn considerable attention because of their beneficial properties and promising therapeutic prospective. Furthermore, MSCs have been applied to various studies related to wound healing, autoim-mune diseases, and organ transplantation. This review discusses the potential functions of MSCs in protecting corneal tissue and their possible mechanisms in corneal wound healing and corneal transplantation.

Effect of amnion membrane transplantation on corneal neovascularization in 10 patients with alkali burn

By observing clinical cases, we studied the curative effect of amnion membrane transplantation on decreasing corneal neovascularization (CNV). It was a non-randomized retrospective case-control study. Among 17 cases (21 eyes) of third-degree alkali burns from 2007 to 2010, 10 cases (12 eyes) were performed with amnion membrane transplantation operation, and others were not. Amnion membrane transplantation was performed at the 3rd day after burn in the treatment group. Areas of CNV in double groups were measured at the 14th day and 60th day after burn. Area of CNV in the treatment group was (66.207±7.251)mm2 at the 14th day after burn, and was 18.27% lower than that in the control group. Area of CNV in the treatment group was (120.046±13.812)mm2 at the 60th day after burn, and was 11.35% lower than that in the control group. There was both statistical significance (P<0.05). Amnion membrane transplantation operation can inhibit the growth of corneal neovascularization induced by alkali burn.

Preoperative evaluation and outcome of corneal transplantation for limbal dermoids：aten-yearfollow-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.

The lived experiences of patients undergoing acellular porcine corneal stroma transplantation

To explore the lived experiences of patients undergoing acellular porcine corneal stroma（APCS）transplantation,a descriptive,qualitative design was performed.A purposive sample of 13 patients who underwent APCS transplantation to treat progressive infectious keratitis were enrolled in the semi-structured,open-ended interviews.The taped and transcribed interviews were analyzed using a thematic analysis approach.Alterations in the transparency of APCS grafts were accompanied by a gradual improved visual acuity（before surgery：1.38±0.91 logMAR;3mo postoperatively ：0.40±0.24 logMAR, respectively）.Accordingly,in terms of lived experiences,the patients generally reported＂negative＂experiences before the operation and during the early postoperative period,but this was greatly improved 3mo after surgery.Four main themes were derived：anxiety and fear,stigma,lifestyle change,and gratitude and insights. Conclusively,health care professionals should provide holistic care for patients,proactively promoting patients’physical and mental health.

Organ transplantation scandal influencing corneal donation rate

~ In the majority of countries, there is a shortage of donor corneas for corneal transplantations. This study investigated the impact of organ transplantation scandals on corneal donation rate at the University Hospital T/ibingen. Each deceased patient was considered as a potential corneal donor. An ophthalmic resident handled with stable methods of procedures the corneal donor procurement from 2009 to 2015. The rates of corneal donation were examined and analyzed. Among the 5712 hospital deaths, consent for corneal donation was obtained in 711 cases. The mean annual corneal donation rate was 12.4%. Since 2009, the donation rate per year could be increased with exception of 2013 and 2015. In the end of 2012 and 2014 two huge organ donation scandals were known in Germany. In the following years 2013 and 2015 corneal donation rate decreased significantly （P=0.0181 and P=0.0006）. We concluded that transplantation scandals have a significant impact on corneal donation rate. Improving professional＇s performance through full transparency and honesty is very important to earn trust of potential donors and their families.

Amniotic membrane transplantation in a patient with impending perforated corneal ulcer caused by Streptococcus mitis: A case report and review of literature

BACKGROUND Streptococcus mitis(S.mitis)is an opportunistic pathogen that can lead to severe ocular infections.In previous reports,penetrating keratoplasty(PK)was usually adopted for the treatment of persistent corneal ulcers.This report describes an unusual case of nonhealing descemetocele caused by S.mitis treated by antibiotics plus amniotic membrane transplantation(AMT).CASE SUMMARY A 63-year-old woman presented with a right persistent corneal ulcer that she had suffered from for the past 9 mo.The culture of a corneal scraping yielded S.mitis.The right eye descemetocele decreased in diameter from 3 to 0.8 mm after the continuous administration of topical vancomycin and ceftriaxone for 2 wk.Due to the slow healing,AMT was performed.Her corneal erosion healed and gradually became clear.Her visual acuity recovered from initially counting fingers to 100/200 at the last follow-up,67 mo after AMT.CONCLUSION Antibiotics plus AMT may be an effective alternative treatment other than PK to promote epithelializationand to reduce inflammation in the corneas complicated by S. mitis keratitis.

A 60-Year-Male Post Corneal Transplantation with Acute Pneumonia

Pneumonia is a common complication in organ transplantation patients. Multiple respiratory pathogens such as bacteria, viruses and fungi are potentially coexisted. A 60-year-old male with left eye post corneal transplantation developed acute severe pneumonia caused by Pneumocystis jiroveci (PJP) coinfection with Nocardia spp. and Cytomegalovirus (CMV). He was hospitalized due to acute respiratory failure. Chest radiographs and chest Computed Tomography (CT) revealed extensive ground-glass opacities. PJP was diagnosed from Bronchoalveolar Lavage Fluid (BALF). The pneumonia was persistent despite of receiving intravenous cotrimoxazole. Tracheal aspirate showed faint gram-positive filamentous beaded branching organisms. Consequently Nocardia spp. was proven. Intravenous cotrimoxazole was continued and intravenous imipenem was added. After a course of dual antibiotics, pneumonia was gradually improved. A week after, he developed the worsened acute respiratory failure. The bronchoscopy was performed. The new pathogens were not detected from BALF microbiology. The BALF cytology was unremarkable. PJP was detected by Polymerase Chain Reaction (PCR) from BALF. CMV antigenemia was detected from BALF and blood. Intravenous ganciclovir was given. This report describes PJP coinfected with Nocardia spp. and CMV in post corneal transplantation patient suffering from severe pneumonia. Multiple respiratory pathogens are common among transplantation patients representing host immunosuppression and inadequate antimicorbial prophylaxis.

Clinical analysis of patients with hepatocellular carcinoma recurrence after living-donor liver transplantation

AIM: To evaluated patterns and outcomes of hepatocellular carcinoma (HCC) recurrence after living donor liver transplantation (LDLT).METHODS: From 2001 to 2014, 293 patients underwent LDLT for HCC at our transplant center. We retrospectively reviewed 54 (18.4%) patients with HCC recurrence after LDLT. We evaluated patterns and outcomes of HCC recurrence after LDLT, with particular attention to the Milan criteria at transplantation, treatments for HCC-recurrent patients, and factors related to survival after HCC recurrence. Furthermore, we evaluated the efficacy of combination treatment of sorafenib and an mTOR inhibitor.RESULTS: The 1-, 2-, and 3-year overall survival rates after HCC recurrence were 41.1%, 20.5%, and 15.4%, respectively. The median time interval between LDLT and HCC recurrence was 6.5 mo. Although recurrence rates according to the Milan criteria at LDLT were significantly different, HCC recurrence patterns and survival rates after HCC recurrence were not significantly different between the two groups. Time to recurrence &#x0003c; 12 mo (P = 0.048), multiple recurrences at HCC recurrence (P = 0.038), and palliative treatment for recurrent tumors (P = 0.003) were significant independent prognostic factors for poor survival after HCC recurrence in a multivariate analysis. The combination treatment of sorafenib and sirolimus showed survival benefits in the palliative treatment group (P = 0.005).CONCLUSION: Curative treatment for recurrent HCC after LDLT is the most important factor in survival rates after HCC recurrence and combination treatments of sorafenib and an mTOR inhibitor could have survival benefits in patients with HCC recurrence after LT in the palliative treatment group.

Effects of Ad-p27mt Gene Transfer on the Expression of Bax,Bcl-2,VEGF and MMP-9 in the Transplanted Liver Tumors in Nude Mice

In this study, the mechanism by which Ad-p27mt inhibits the growth, invasion and metastasis of transplanted liver tumor was studied by examining the effects of Ad-27mt gene transfer on the expression of Bax, Bcl-2, VEGF and MMP-9 in the transplanted liver tumors in nude mice.The model of transplanted hepatic tumor was established in nude mice.The mice were then divided into three groups, which were injected with PBS, Ad-LacZ and Ad-p27mt and the growth of the transplanted liver tumor was observed.The expressions of P27, Bax and Bcl-2 proteins were detected by Western blotting and the expressions of VEGF and MMP-9 were immunohistochemically determined.Our result showed that the tumor size, expressions of Bax, Bcl-2 proteins, VEGF and MMP-9 were all lower than those in PBS and Ad-LacZ groups and the differences were statistically significant (P【0.05).Our study suggested that Ad-p27mt could inhibit the growth, invasion and metastasis of hepatic cancer by lowering the expressions of VEGF and MMP-9.

Simultaneous tectonic Descemet stripping endothelial keratoplasty and tectonic Bowman layer transplant for the management of corneal perforation

AIM:To report the outcomes of three cases of corneal perforation managed with simultaneous tectonic Descemet stripping endothelial keratoplasty(t-DSEK)and tectonic Bowman layer transplant(t-BLT)as an alternative to tectonic penetrating keratoplasty(t-PKP).METHODS:Three eyes of three patients receiving simultaneous t-DSEK and t-BLT for corneal perforation were included.The technique for DSEK was modified depending on individual requirements.The t-BLT technique was standardised using an 8 mm graft and fixated with a running suture.Success was measured by the ability of this procedure to close a corneal perforation.RESULTS:All three cases achieved tectonic eye globe restoration and remained stable during the minimum 3-month observation period.Reinterventions were relatively common:2 cases required amniotic membrane transplant for persistent epithelial defects.One case required DSEK rebubbling.One case developed angle closure glaucoma requiring surgical peripheral iridectomy.CONCLUSION:Simultaneous t-DSEK and t-BLT may be a useful strategy for the management of corneal perforation as an alternative management to t-PKP for selected cases.

Treatment of superficial corneal opacities with corneal stromal lenticule obtained through SMILE surgery

AIM:To evaluate the clinical efficacy and feasibility of superficial corneal opacities treated by excimer laser phototherapeutic keratectomy(PTK)combined with small incision lenticule extraction(SMILE)-derived corneal stromal lenticule transplantation.METHODS:A retrospective interventional case series of nine patients aged 12-59y with superficial corneal opacity caused by different pathologies who underwent standardized PTK combined with SMILE-derived corneal stromal lenticule transplantation was examined.Lenticule patches were fixed with fibrin glue.All patients underwent pre-and post-operative clinical assessments at different times for up to 12mo.Slit lamp microscopy,corneal density,uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),and anterior segment optical coherence tomography(AS-OCT)were examined.RESULTS:The patients’mean age was 36.00±5.80(12-59)y.Seven eyes(77.8%)gained UDVA and CDVA at the last measurement compared to their preoperative levels.The densities of the total cornea,the total anterior corneal layer,and the anterior corneal layers of 0-2 and 2-6 mm decreased significantly by 12.4%,27.5%,46.7%,and 32.8%,respectively.After human allogeneic transplantation,the implanted lenticules of all eyes were clearly visible by AS-OCT and remained transparent without displacement or graft rejection.The thickness of the central cornea and corneal lenticule transplants were stable throughout the entire postoperative period.One case experienced the postoperative complication of delayed corneal epithelial healing.CONCLUSION:PTK combined with SMILE-derived corneal lenticule transplantation improves long-term visual acuity.Therefore,it is a new,safe,and effective method for treating superficial corneal opacity.

腺病毒介导的p27mt基因转染对肝癌细胞及裸鼠移植瘤的生长抑制作用

目的:研究携带突变型p27的重组腺病毒(Ad-p27mt)基因转染对肝癌的体内、外抑制作用,并探讨其抑癌机制。方法:⑴将Ad-p27mt转染人肝癌细胞SMMC-7721,Western blotting检测P27、Bcl-2、Bax的表达;流式细胞仪(FCM)观察Ad-p27mt对肝癌细胞生长抑制作用。⑵Ad-p27mt直接注射入人肝癌裸鼠移植瘤中,绘制肿瘤生长曲线,计算肿瘤生长抑制率。结果:Ad-p27mt转染肝癌细胞后,细胞增殖明显受抑制,G0/G1期细胞比例增加,P27表达增强,Bax/Bcl-2比例增高,采用Ad-p27mt基因治疗肝癌裸鼠移植瘤生长受抑制,肿瘤生长抑制率达57.09%。结论:Ad-p27mt基因转染对肝癌具有较显著的体内、外抑制作用和诱导凋亡作用,其机制是通过增强P27表达,使细胞产生周期阻滞,诱导凋亡的机理可能是上调Bax/Bcl-2比例所引起。

移植物厚度对角膜内皮失代偿行简易后弹力层角膜内皮移植效果的影响

背景:研究表明较薄移植物视力恢复更快、排斥风险更低,国内缺乏对内皮移植术后不同植片厚度的临床疗效分析,因此,确定最佳移植物厚度对于提高手术疗效至关重要。目的:评价简易后弹力层剥离内皮角膜移植术后不同植片厚度对视力恢复及其他预后指标的影响。方法:选取2013年1月至2023年2月在北部战区总医院接受简易后弹力层剥离内皮角膜移植手术治疗的角膜内皮失代偿患者共72例(72眼),其中薄植片组(<100μm)32例(32眼),厚植片组(≥100μm)40例(40眼)。随访1年,观察两组术前及术后1,3,6,12个月的最佳矫正视力,术后1年角膜内皮细胞数、角膜植片透明度、术后并发症、植片生存情况。结果与结论:①两组患者术后视力较术前均有显著提高,薄植片组患者术后3个月最佳矫正视力优于厚植片组(P<0.05);②两组术后1年角膜内皮细胞数及植片透明度比较差异无显著性意义(P>0.05);③两组患者继发性青光眼、植片免疫排斥、植片移位等术后并发症发生率比较差异无显著性意义(P>0.05);④两组术后1年植片生存率比较差异无显著性意义(93.8%,92.3%,P>0.05);⑤结论:简易后弹力层剥离内皮角膜移植术是一种安全有效的角膜内皮移植手术方式,其术后疗效与传统后弹力层剥离内皮角膜移植术相似,而且植片植入方式更为简便。较薄植片能够更早提供最佳矫正视力,更早完成角膜重塑,因此在治疗角膜内皮失代偿疾病时,优先选择薄移植物来提高恢复时间。

Tocilizumab promotes corneal allograft survival in rats by modulating Treg-Th17 balance

AIM: To examine the therapeutic effects of tocilizumab on experimental corneal transplantation and its effect on Treg/Th17 balance. METHODS: Allograft corneal graft was performed between host Sprague Dawley and Wistar donor rats.The rats were randomly divided into four groups: normal,autograft, allograft, and allograft treated with tocilizumab.Kaplan-Meier was performed to draw the survival curve.The protein levels of interleukin-17A(IL-17A), vascular endothelial growth factor(VEGF), and forkhead box protein3(Foxp3) were measured by immunohistochemistry.The mRNA levels of IL-17A, VEGF, retinoid-related orphan receptor gammat(RORγt), interleukin-6(IL-6) and Foxp3 were detected by reverse transcription real-time polymerase chain reaction(RT-PCR). The Treg and Th17 cells were investigated by flow cytometry. RESULTS: The survival time of tocilizumab group was(24±1.27 d) longer than that of allograft group(10±0.55 d).Moreover, immunohistochemical examination revealed that IL-17A and VEGF protein levels in the allograft group were significantly higher than that of tocilizumab group(P<0.01),while Foxp3 levels in the allograft group was significantly lower than that of the tocilizumab treated group(P<0.001).Flow cytometry showed that the number of Th17 cellsin allograft group was significantly higher than that in tocilizumab group(P<0.001). Meanwhile, the number of Tregs was significantly lower than in tocilizumab group(P<0.001). Simultaneously, Foxp3 m RNA expression level in corneal tissues of tocilizumab treated group was significantly higher than other groups(P<0.001). CONCLUSION: These findings suggest that tocilizumab may promote corneal allograft survival, possibly by modulating Treg-Th17 balance.

Ipsilateral Lymphadenectomy to Inhibit Corneal Allograft Rejection in Rats

In order to investigate the ipsilateral lymphadenectomy for inhibiting rejection in rat corneal transplantation, corneal allogenic transplantation models were established in rats. Eighteen female Wister rats were used as donors, and 36 Sprague Dawley rats as recipients. After penetrating corneal transplantation, recipients were randomly divided into 3 groups: group A (control group); group B, the ipsilateral lymphadenectomy group; group C, the bilateral lymphadenectomy group. Among 12 rats in each group, the corneas of 2 rats in each group were used for pathological study at day 14 after the transplantation, and the remaining 10 rats were used for studying corneal rejection by a slit lamp. The time points when allograft rejection occurred were recorded and mean survival time (MST) was compared. The results showed that MST in groups B and C was 46 30±9 464 days and 44 43±7 604 days, respectively, which was significantly prolonged as compared with that in group A (10 71±1 567 days, P<0.01). There was no significant difference in MST between groups B and C (P>0.05). It was concluded that both bilateral and ipsilateral lymphadenectomy therapies could effectively inhibit the corneal allograft rejection. Ipsilateral lymphadenectomy is a less complex surgical procedure and is just as effective in preventing rejection.

RMT1-10体外诱导耐受性树突状细胞对小鼠高危角膜移植排斥反应的抑制作用及其机制

目的探讨RMT1-10体外诱导耐受性树突状细胞(Tol-DCs)对小鼠高危角膜移植排斥反应的抑制作用及其机制。方法选取SPF级雄性BALB/c小鼠100只和C57BL/6小鼠50只,获取C57BL/6小鼠骨髓来源的未成熟树突状细胞(imDCs),按照诱导干预不同分为imDCs组(不干预)、成熟树突状细胞(mDCs)组(加入脂多糖)、RMT1-10组(加入RMT1-10和脂多糖)和IgG同型对照组(加入IgG同型抗体和脂多糖),培养7 d后采用流式细胞术检测各组DCs表型CD11c、CD80、CD86、主要组织相容性复合物(MHC)-Ⅱ、T细胞免疫球蛋白和黏蛋白结构域分子(Tim)-4和CD103表达水平;采用酶联免疫吸附法测定细胞培养液上清液中白细胞介素10(IL-10)和转化生长因子β(TGF-β)质量浓度。建立混合淋巴细胞培养体系,采用细胞计数试剂盒8法检测各组DCs刺激CD4^(+)T细胞增生的刺激指数(SI)。以角膜基质缝线法诱导BALB/c小鼠角膜新生血管,以4个象限新生血管均匀长入角膜中周区的小鼠作为受体。将80只受体小鼠采用随机数字表法随机分为imDCs组、mDCs组、RMT1-10组和IgG同型对照组,每组20只,各组分别于尾静脉注射相应DCs(1×10^(6)个/100μl)。注射后7 d,以C57BL/6小鼠为供体行穿透角膜移植术。术后1个月,每日裂隙灯显微镜下观察受体小鼠角膜植片排斥体征,包括角膜混浊、水肿及新生血管。术后21 d,每组抽取5只受体小鼠,耳廓皮下注射20μl(1×10^(6)个细胞)正常C57BL/6小鼠脾脏细胞,24 h后测量耳廓肿胀度评价迟发型超敏反应(DTH)。结果RMT1-10组DCs中CD80、CD86、MHC-Ⅱ和Tim-4阳性细胞占CD11c阳性细胞百分比均明显低于mDCs组,差异均有统计学意义(均P<0.001);RMT1-10组Tim-4阳性细胞百分比明显低于imDCs组,CD103阳性细胞百分比明显高于其他3个组,差异均有统计学意义(均P<0.001)。RMT1-10组细胞培养上清液中IL-10和TGF-β质量浓度明显高于其他组,差异均有统计学意义(均P<0.001)。各组DCs对CD4^(+)T细胞增生的SI总体比较,差异均有统计学意义(F_(分组)=1833.00,P<0.001;F_(比例)=230.40,P<0.001)。在每一细胞比例内,imDCs组SI均明显低于mDCs组,RMT1-10组SI均明显低于imDCs组,差异均有统计学意义(均P<0.05)。各组角膜植片生存曲线总体差异有统计学意义(χ^(2)=77.69,P<0.001),其中RMT1-10组角膜植片存活数量明显多于imDCs组,imDCs组角膜植片存活数量明显多于mDCs组,差异均有统计学意义(χ^(2)=9.74、31.02,均P<0.01)。阳性对照组、mDCs组、IgG同型对照组、imDCs组、RMT1-10组和阴性对照组小鼠耳廓肿胀度分别为(503.6±17.2)、(475.7±17.6)、(456.2±18.8)、(225.2±39.4)、(118.1±12.6)和(106.4±7.4)μm,总体比较差异有统计学意义(F=377.10,P<0.001),其中mDCs组小鼠耳廓肿胀度略低于阳性对照组,imDCs组小鼠耳廓肿胀度明显低于IgG同型对照组,明显高于RMT1-10组,差异均有统计学意义(均P<0.05)。结论RMT1-10可抑制小鼠高危角膜移植排斥反应,其作用机制可能为体外诱导imDCs转化为Tol-DCs并上调TGF-β和IL-10表达,经过继转移后促进受体抗原特异性免疫耐受,进而间接延长角膜植片存活时间。

Corneal stem cells and tissue engineering: Current advances and future perspectives

Major advances are currently being made in regenerative medicine for cornea. Stem cell-based therapies represent a novel strategy that may substitute conventional corneal transplantation, albeit there aremany challenges ahead given the singularities of each cellular layer of the cornea. This review recapitulates the current data on corneal epithelial stem cells, corneal stromal stem cells and corneal endothelial cell progenitors. Corneal limbal autografts containing epithelial stem cells have been transplanted in humans for more than 20 years with great successful rates, and researchers now focus on ex vivo cultures and other cell lineages to transplant to the ocular surface. A small population of cells in the corneal endothelium was recently reported to have self-renewal capacity, although they do not proliferate in vivo. Two main obstacles have hindered endothelial cell transplantation to date: culture protocols and cell delivery methods to the posterior cornea in vivo. Human corneal stromal stem cells have been identified shortly after the recognition of precursors of endothelial cells. Stromal stem cells may have the potential to provide a direct cell-based therapeutic approach when injected to corneal scars. Furthermore, they exhibit the ability to deposit organized connective tissue in vitro and may be useful in corneal stroma engineering in the future. Recent advances and future perspectives in the field are discussed.

Observation of Long-term Efficacy of Corneal Limbal Conjunctival Autografts in Microscopy Treatments of Pterygium

Purpose: To compare the long-term efficacy of a corneal limbal conjunctival autograft combined with pterygium excision in the treatment of primary pterygium. Methods: This random control study included 63 patients (63 eyes) with primary pterygium. These were randomly divided into a group with corneal limbal conjunctival autograft combined with pterygium excision (group A) and a group with pterygium excision with exposed sclera (group B) and subjected to long-term follow up. The surgical outcomes were classified and evaluated (grade Ⅰ-Ⅳ). Several indexes were analyzed, including ocular surface irritation symptom,tear film stability, surgical complication, and recurrence rate. Results: The follow up ranged from 24 to 38 months, (26.9± 3.4) months on average. No recurrence was noted at 6 weeks postoperatively. At 6 months postoperatively, the recurrence rate of pterygium was 5.2% in group A and 8.0% in group B. At 1 year postoperatively, the recurrence rate in group A was 10.5% and 20.0% in group B. At the end of follow up, the recurrence rates were 13.1% in group A and 24.0% in group B. No statistical significance was found between two groups regarding the recurrence rates at each time point (P>0.05). After the follow up. (> 2 years),the severity of ocular surface conditions was significantly milder in patients in group A than in group B (P <0.01).No statistically significant differences were noted between the two groups at 6 weeks,6 months, and 1 year after surgery. No statistically significant differences were observed between the two groups regarding postoperative tear film break-up time. Fewer postoperative complications and milder ocular surface irritation symptoms occurred in patients in group A. Conclusion: Corneal limbal conjunctival autograft combined with pterygium excision yields sound long-term efficacy and a low recurrence rate and induces only mild damage on the ocular surface when used as a treatment for pterygium.

An Association between Corneal Inflammation and Corneal Lymphangiogenesis after Keratoplasty

Purpose:.To examine the relationship between corneal inflammation and corneal lymphangiogenesis after keratoplasty.Methods:.Rat corneal lymphangiogenesis was examined by lymphatic vessel endothelial receptor(LYVE-1) immunohistochemistry and whole mount immunofluorescence at 1, 3, 7,10, and 14 days after corneal transplantation. Corneal inflammation was evaluated by inflammation index(IF) grading and NF-κB immunohistochemistry at the same time points. The association between lymphatic vessel counting(LVC) and the IF scores was then examined.Results:.LYVE-1 positive lymphatic vessels occurred in the corneal stroma on day 3,.developed throughout days 7 and10,.and peaked in number at day 14 after keratoplasty.Corneal inflammation was strong on day 3, and then resolved gradually,.but increased again from days 7 to 14 after the transplantation..LVC was strongly and positively correlated with IF after keratoplasty(r=0.41;P<0.05). However, changes in IF scores and LVC were not parallel.Conclusion:.A close,.but not parallel,.relationship was found between corneal lymphangiogenesis and corneal inflammation after corneal transplantation.

Application of Femtosecond Laser in Ocular Surgery

The femtosecond laser is a type of laser that can produce pulses of light of extremely short duration.The application of femtosecond laser in surgery results in no thermal effect or shock wave,so that this laser is unlikely to cause tissue injuries outside the irradiation area of the laser beam. The femtosecond laser shows promising applications in refractive surgery and corneal transplantation due to its high precision and predictability. In this paper, we review the clinical application of the femtosecond laser in refractive surgery and corneal transplantation.