角膜移植后患者角膜新生淋巴管与新生血管和炎症的关联

目的:研究角膜移植后角膜新生淋巴管与新生血管和炎症的关联。方法:人角膜取自行二次角膜移植的患者19例。淋巴内皮细胞受体(lymphatic vessel endothelial hyaluronan receptor,LYVE-1)和内皮细胞黏附因子-1(platelet endothelial celladhesion modecule-1,PECAM-1)双重免疫组化法标记角膜中的新生血管和淋巴管,进行淋巴管计数(lymphatic ves-sels counting,LVC)和血管计数(blood vessels counting,BVC),比较BVC、炎症指数(inflammation index,IF)、移植历史(transplantation history,TH)与LVC之间的关联。结果:角膜移植后BVC,IF与LVC间均呈显著性正相关,而TH与LVC间呈显著性负相关。角膜移植后新生淋巴管、血管、眼表炎症间大致成平行发展,新生淋巴管最先退化,其次是眼表炎症,新生血管最后消退。结论:人角膜移植后角膜新生淋巴管与新生血管、眼表炎症之间存在着极为密切的关联。     

碱烧伤人角膜组织新生淋巴管的检测

目的 探讨人角膜碱烧伤后新生淋巴管的生长情况及其影响因素.方法 回顾性系列病例研究.分析2005年1至12月期间在中山大学中山眼科中心因角膜碱烧伤住院手术治疗的22例(22只眼)患者.记录患眼的烧伤时间(IT)和损伤等级(ID),并测量炎性反应指数(II)和角膜新生血管的相对面积(BVA);应用双重酶组织化学、免疫组织化学染色及透射电镜检测角膜标本的新生淋巴管(LVC)和血管(BVC);采用苏木素-伊红染色检测多形核白细胞(PMN)浸润情况.结果 采用配对Student t检验、Pearson相关检验及Stepwise回归进行统计学分析.结果 22例患者观测结果 IT为(57.62±31.72)个月、ID为(12.00±2.76)分、II为(2.32±2.63)分、BVA为29.79%±18.61%、BVC为(14.45±9.29)个、LVC为(2.73±4.57)个、PMN为(13.45±13.09)个,其中7例(占32%,IT<64个月)同时存在角膜新生淋巴管(8.6±3.8)个和血管(22.3±11.1)个,LVC总数为60个,占发生新生淋巴管的角膜中总管腔数(BVC和LVC,378个)的16%.LVC与IT、ID、BVA、PMN、II的相关系数分别为-0.673、0.604、0.755、0.806、0.873,均P<0.05;进一步回顾分析得出LVC近似等于II和BVA分别和特定的常数相乘后取和所得的淋巴管指数(LI).透射电镜从微观上证实了碱烧伤人角膜组织中存在具有典型结构特征的新生淋巴管和炎性细胞浸润.结论 碱烧伤后部分角膜组织存在新生淋巴管,通过II和BVA可间接估计其发生情况.LI是一项评估碱烧伤角膜新生淋巴管的有用临床参数.(中华眼科杂志,2009,45:115-121)     

角膜移植后角膜新生淋巴管与新生血管间的关联

目的:研究角膜移植后角膜新生淋巴管与新生血管间关联。方法:人角膜取自行二次角膜移植的19名患者。5核苷酸酶-碱性磷酸酶(5-nase-Alkaline phosphatase,5-NA-ALP)双重酶组织化学染色及淋巴内皮细胞受体(lymphatic vessel endothelial receptor,LYVE-1)、内皮细胞黏附因子-1(platelet endothelial cell adhesion modecule-1,PECAM-1)双重免疫组化法标记角膜中的新生血管和淋巴管,并进行淋巴管计数(lymphatic vessels counting,LVC)和血管计数(blood vessels counting,BVC),比较BVC与LVC之间的关联。结果:角膜中存在角膜新生血管12例(63%),存在角膜新生淋巴管5例(26%)。角膜新生淋巴管仅出现在血管化角膜中。角膜移植后BVC与LVC间呈显著性正相关(r=0.725;P<0.01)。结论:人角膜移植后角膜新生淋巴管与新生血管之间存在密切关联。     

碱烧伤后角膜新生淋巴管的实验研究

目的动态检测大鼠角膜碱烧伤后的角膜新生淋巴管和血管的变化,并阐明二者之间的关联。方法制备大鼠角膜碱烧伤模型,于碱烧伤后1周、2周行角膜组织电镜检查,检测角膜新生淋巴管与新生血管。5’核苷酸酶-碱性磷酸酶(5’-nase-alkaline phos-phatase,5’-NA-ALP)双重酶组织化学染色及全角膜免疫荧光染色分别检测碱烧伤后6h、1d、3d、1周、2周、3周、4周、5周、6周、7周、8周的角膜新生淋巴管和新生血管的动态变化,并进行淋巴管计数(lymphatic vessels counting,LVC)和血管计数(blood vessels counting,BVC)比较。结果电镜观察结果:角膜碱烧伤后1周,角膜基质层出现新生血管,未见淋巴管;碱烧伤后2周,新生血管和新生淋巴管均出现。酶组织化学染色结果显示:碱烧伤后6h有新生血管,1周时角膜基质层存在新生淋巴管,2周时LVC和BVC均达到高峰,分别为(16.41±1.00)个和(50.40±1.56)个;以后逐渐下降,5周时LVC为(0.33±0.50)个,BVC为(12.52±2.51)个;8周时均为0。碱烧伤后,新生淋巴管和新生血管呈显著性正...     

高危角膜移植大鼠排斥反应及VEGF-C/D表达的研究

目的：探讨鼠角膜碱烧伤后VEGF-C/D的表达和意义,以及新生淋巴管在高危角膜移植后排斥反应中的作用。
　　方法：制作角膜碱烧伤模型,取不同时间段角膜进行电镜观察,观察角膜血管化情况;采用免疫组织化学方法检测l、3、5、7、14、28 d角膜组织VEGF-C/D及VEGFR-3的表达;并在角膜中仅有血管(A组),同时存在新生血管及新生淋巴管(B组),新生淋巴管消退期(C组),角膜新生血管消退期(D组)以及正常组(N 组)进行穿透性角膜移植,比较不同角膜植片的排斥反应指数( rejection index, RI)值及存活时间。
　　结果：电镜观察发现,在碱烧伤后第7d时鼠角膜出现新生血管,未出现新生淋巴管,在碱烧伤2 wk时出现新生血管的同时出现淋巴管,5wk时无明显的新生淋巴管,8wk时新生血管逐渐消退;大鼠角膜组织中 VEGF-C/D 及VEGFR-3的表达从第3 d开始明显上升,并于第5 d达到最高峰。角膜移植后N、A、B、C、D组的植片平均存活时间分别为14.25±0.62、9.35±1.02、5.06±1.13、8.71±0.83、9.44±1.05d。组间比较发现,B组植片平均存活时间显著性缩短(P<0.05),A、C、D的存活时间均显著性延长(P<0.05)。
　　结论：角膜碱烧伤后存在VEGF-C/D及VEGFR-3的高表达,而且新生淋巴管能加速高危角膜移植后的免疫排斥反应。     

克拉霉素抑制碱烧伤角膜新生血管的形成

目的 探讨克拉霉素对角膜新生血管形成及角膜内血管内皮生长因子(vascular endothelial growth factor,VEGF) 表达的影响.方法 将42只SD大鼠随机分成正常组6只(6眼) 、胃饲克拉霉素60 mg·kg-1的实验组18只(18眼)、胃饲等量生理盐水的对照组18只(18眼).除正常组外,余36只(36眼)制备大鼠角膜碱烧伤新生血管模型.分别于造模后4 d、7 d、14 d运用裂隙灯、免疫组织化学方法观察新生血管长度及面积、VEGF的表达.结果 实验组与对照组比较,新生血管生长度(t4=25.631,P＜0.05;t7=52.663,P＜0.05;t14=24.840,P＜0.05)短、血管面积(t4=27.668,P＜0.05;t7=51.823,P＜0.05;t14=33.854,P＜0.05)小、VEGF表达低,差异均有统计学意义(P＜0.05).结论 VEGF的表达与角膜新生血管的形成过程密切相关,克拉霉素能减少VEGF的表达来抑制角膜新生血管的发生.     

缺氧诱导因子1α在碱烧伤后兔角膜新生血管形成中的作用

目的 观察碱烧伤后兔角膜新生血管形成的不同时期缺氧诱导因子1α(HIF-1α)在角膜内的表达,探讨HIF-1α对角膜新生血管形成的影响.方法 实验研究.取30只健康家兔,采用随机数字表法分成5组,每组各6只兔,右眼采用1 mol/L氢氧化钠溶液建立角膜碱烧伤模型,左眼作为自身对照.分别于碱烧伤前和碱烧伤后1、3、5、7、14 d,在裂隙灯显微镜下观察家兔角膜新生血管增生情况,HE染色观察角膜组织病理学特征,并采用免疫组织化学法检验角膜组织中HIF-1α的表达,计算炎性细胞(多形核白细胞和淋巴细胞)和HIF-1α阳性细胞核数,对其结果行单因素方差分析及相关分析.结果 角膜碱烧伤后,HIF-1α主要表达在角膜基质中的炎性细胞、血管内皮细胞的细胞核中.随着时间的增加,炎性细胞表达增强,HIF-1α表达量也相应增加,并于碱烧伤后5 d达到高峰,以后逐渐减少.碱烧伤后1、3、5、7、14 d,角膜组织中炎性细胞和HIF-1α表达水平的差异均有统计学意义(F=422.086,437.555;P均＜0.05),且HIF-1α的表达与新生血管的形成在时空上一致.经相关分析,角膜中炎性细胞和HIF-1α阳性细胞表达呈正相关(r=0.860,P＜0.05).结论 碱烧伤后炎症反应能诱导HIF-1α的表达,而HIF-1α能促进角膜新生血管的形成.     

高危角膜移植排斥兔模型的建立及对比研究

背景 理想的角膜移植排斥动物模型是研究高危角膜移植免疫排斥机制的基础,具有重要的意义. 目的 比较各种建立兔高危角膜移植排斥模型方法的临床特点,探索合适的角膜移植排斥动物模型的建立方法.方法 45只新西兰白兔作为角膜移植受体,并按照造模方法的不同按随机数字表法随机分为缝线组、碱烧伤组和异种移植组,每组15只.分别用在角膜4个象限各间断缝1根5-0丝线法和1 mol/LNaOH碱烧伤法诱导角膜新生血管(CNV),再建立兔同种异体角膜移植；另一组以猫角膜为供体,建立猫-兔异种角膜移植模型.于第2周和第4周观察植片的组织学情况,对3个组角膜植片裂隙灯下观察植片排斥反应、炎症和新生血管,对植片水肿程度及炎症指数(IF)进行评分,根据角膜混浊、水肿及新生血管合计值计算排斥指数(RI).用免疫组织化学法检测CD4+T细胞和CD8+T细胞在植片组织中的表达. 结果 缝线组、碱烧伤组和异种移植组分别有14、15、15只兔完成穿透角膜移植术.术后2周,3个组IF中位数分别为0.556、0.778、0.222,差异有统计学意义(H=25.736,P=0.000),异种移植组IF值低于缝线组和碱烧伤组,差异均有统计学意义(Z=3.841、3.993,P=0.000),缝线组IF值低于碱烧伤组,差异有统计学意义(Z=3.568,P=0.000).术后2周,3个组RI中位数分别为2、6、3,差异有统计学意义(H=22.432,P=0.000),异种移植组RI高于缝线组而低于碱烧伤组,差异均有统计学意义(Z=2.373,P=0.018；Z=3.936,P=0.000),缝线组RI低于碱烧伤组,差异有统计学意义(Z=3.729,P=0.000).3个组植片存活时间分别为(17.9±2.0)、(13.4±2.4)、(15.5±2.0)d,差异有统计学意义(F=9.474,P=0.001).异种移植组的新生血管面积均低于缝线组和碱烧伤组(P＜0.05).术后2周和4周,组织病理学检查可见异种移植组植片中的炎性细胞少于缝线组和碱烧伤组,3个组植片中均出现以CD4+T细胞为主的细胞浸润. 结论 猫-兔异种角膜移植模型较缝线和碱烧伤法制作的角膜移植模型炎症反应轻、新生血管少,角膜免疫排斥反应稳定、适度,是理想的高危角膜移植动物模型.     

缺氧诱导因子1α在碱烧伤后兔角膜新生血管形成中的作用

目的 观察碱烧伤后兔角膜新生血管形成的不同时期缺氧诱导因子1α（HIF-1α）在角膜内的表达,探讨HIF-1α对角膜新生血管形成的影响.方法 实验研究.取30只健康家兔,采用随机数字表法分成5组,每组各6只兔,右眼采用1 mol/L氢氧化钠溶液建立角膜碱烧伤模型,左眼作为自身对照.分别于碱烧伤前和碱烧伤后1、3、5、7、14 d,在裂隙灯显微镜下观察家兔角膜新生血管增生情况,HE染色观察角膜组织病理学特征,并采用免疫组织化学法检验角膜组织中HIF-1α的表达,计算炎性细胞（多形核白细胞和淋巴细胞）和HIF-1α阳性细胞核数,对其结果行单因素方差分析及相关分析.结果 角膜碱烧伤后,HIF-1α主要表达在角膜基质中的炎性细胞、血管内皮细胞的细胞核中.随着时间的增加,炎性细胞表达增强,HIF-1α表达量也相应增加,并于碱烧伤后5 d达到高峰,以后逐渐减少.碱烧伤后1、3、5、7、14 d,角膜组织中炎性细胞和HIF-1α表达水平的差异均有统计学意义（F=422.086,437.555;P均＜0.05）,且HIF-1α的表达与新生血管的形成在时空上一致.经相关分析,角膜中炎性细胞和HIF-1α阳性细胞表达呈正相关（r=0.860,P＜0.05）.结论 碱烧伤后炎症反应能诱导HIF-1α的表达,而HIF-1α能促进角膜新生血管的形成.     

Bevacizumab对大鼠角膜新生血管的抑制作用

目的 观察bevacizumab对角膜新生血管的抑制作用.方法 选取鼠龄6～8周、体质量(180±10)g的雄性Wistar大鼠40只,建立碱烧伤角膜新生血管模型;将大鼠随杌分为3个不同剂量药物治疗组(实验组)和1个对照组,每组10只(20眼),大鼠角膜碱烧伤后分别给予结膜下注射不同剂量(0.5 mg、1.0 mg、2.0 mg)的bevacizumab,对照组注入生理盐水;然后进行角膜新生血管的各项数据观察,观察期为16 d,主要观察项目包括各组角膜新生血管的生长情况;计算角膜新生血管的生长面积;碱烧伤后第7天和第16天后采集角膜,标本行组织病理学检测和免疫组织化学检测,第16天,计算平均OD值;评价药物对角膜新生血管的抑制效果.结果 碱烧伤后第7天、第14天,实验组与对照组新生血管面积比较差异均有统计学意义(均为P＜0.05);组织病理学检测发现各实验组炎性细胞浸润、新生血管形成均明显轻于对照组.对照组血管内皮生长因子(vascular endothelial growth factor,VEGF)染色明显增强,实验组的表达明显减弱.碱烧伤后第16天,实验组与对照组比较,VEGF染色阳性细胞数和VEGF平均OD值差异均有统计学意义(均为P＜0.05).碱烧伤后第7天、第16天大鼠角膜CD34的免疫组织化学检测结果及新生血管密度计数方面,实验组和对照组比较差异均有统计学意义(均为P＜0.05).结论 结膜下注射一定浓度的bevacizumab对大鼠角膜碱烧伤后的新生血管生长有抑制作用.     

Corneal lymphangiogenesis correlates closely with hemangiogenesis after keratoplasty

AIM: To examine the relationship between corneal lymphangiogenesis and hemangiogenesis after keratoplasty. · METHODS: Nineteen human corneas were obtained from 19 patients undergoing a second corneal transplantation in Zhongshan Ophthalmic Center in 2005. Blood and lymphatic vessels in human transplanted corneas were identified by lymphatic vessel endothelial receptor (LYVE-1) and platelet endothelial cell adhesion modecule-1 (PECAM-1) immunohi- stochemistry, and double enzyme-histochemistry; then the association of corneal blood vessel counting (BVC) with lymphatic vessel counting (LVC) was examined. · RESULTS: Corneal hemangiogenesis was present in 12 cases (63%), and lymphangiogenesis occurred in 5 cases (26%) human transplanted corneas. In addition, corneal lymphangiogenesis was only present in vascularized corneas. LVC was strongly and positively correlated with BVC(r=0.725, P <0.01). · CONCLUSION: Corneal lymphangiogenesis develops after keratoplasty and strongly associates with hemangiogenesis.     

Crucial role of corneal lymphangiogenesis for allograft rejection in alkali‐burned cornea bed

Backgroud: To examine the time course of hemangiogenesis, lymphangiogenesis, inflammation after corneal alkaline burns and compare with the importance of corneal hemangiogenesis, lymphangiogenesis and inflammation in allograft rejection on alkali‐burned cornea bed, respectively. Methods: Rat corneal hemangiogenesis and lymphangiogenesis were examined by whole mount immunofluorescence and double enzyme‐histochemistry, and the state of corneal inflammation was evaluated by inflammation index scoring and histopathology. Then, corneal transplantations were divided into six groups and performed before the burn (group A) and on day 3 (group B), 2 weeks (group C), 5 weeks (group D), 6 weeks (group E) and 8 weeks (group F) after alkaline burns, respectively. The immune rejection of grafts was evaluated by interferon‐γ, interleukin‐2 enzyme‐linked immunosorbent assay and slit‐lamp examination. Results: Both corneal lymphatic and blood vessels reached the top 2 weeks after the burn. Corneal lymphangiogenesis disappeared 5 weeks after the burn, and corneal hemangiogenesis regressed completely 3 weeks later. Corneal inflammation was strong on day 3, but resolved 6 weeks after the burn. Compared with other groups, the mean survival time of groups B (4.67 ± 1.03 days) and C (5.00 ± 0.63 days) was significantly shorter (P < 0.05). The difference of mean survival time of grafts between group D (9.50 ± 1.05 days) and group E (9.83 ± 0.75 days), between group D and group F (10.00 ± 0.89 days) was not significant (P > 0.05). Conclusions: Corneal lymphangiogenesis presents for a shorter duration than corneal hemangiogenesis or corneal inflammation but plays a crucial role in allograft rejection on alkali‐burned cornea bed.     

Clinical and experimental research of corneal lymphangiogenesis after keratoplasty

The objective of this study is to provide further evidence that corneal lymphangiogenesis occurs after keratoplasty, and to explore the association of corneal hemangiogenesis, corneal inflammation and transplantation history with corneal lymphangiogenesis. Rat corneal lymphangiogenesis was examined by electron microscopy, lymphatic vessel endothelial receptor (LYVE-1) immunohistochemistry, and whole-mount immunofluorescence at 1, 3, 7, 10 and 14 days after corneal transplantation. Blood and lymphatic vessels in human transplanted corneas were identified by LYVE-1 and CD(31) immunohistochemistry, then the association between corneal blood vessel counting, inflammatory index and transplantation history with the lymphatic vessel counting was examined. The results showed that corneal lymphangiogenesis was present in all rat corneas and 26% of human transplanted corneas. Lymphatic vessel counting was significantly associated with blood vessel counting, inflammatory index and transplantation history (all p values <0.0001). We conclude that corneal lymphangiogenesis develops after keratoplasty, and is strongly associated with hemangiogenesis, inflammation and the history of transplantation.     

Development of new lymphatic vessels in alkali‐burned corneas

Purpose: Corneal lymphangiogenesis provides an exit route for antigen‐presenting cells to regional lymph nodes, inducing immune response. The purpose of this study was to examine the development of corneal lymphatic vessels in alkali‐burned corneas. Methods: Corneal lymphatic vessels were examined by electron microscopy, 5′‐nase‐alkaline phosphatase (5′‐NA‐ALP) double enzyme‐histochemistry and whole mount immunofluorescence at 6 hr, 1 day, 3 days, and 1, 2, 3, 4, 5, 6, 7 and 8 weeks after rat corneal alkali injury. The expression of vascular endothelial growth factor‐C (VEGF‐C) protein and mRNA was examined 1, 3, 5, 7, 9, 11 and 14 days after the injury. Results: Corneal lymphangiogenesis developed 3 days after alkaline burns, reached its peak 2 weeks after the injury, decreased gradually and disappeared at the end of the fifth week. The expression of VEGF‐C in burned corneas increased dramatically on the third day but disappeared the 14th day after the injury. Conclusion: Corneal lymphatic vessels develop after alkaline burns and VEGF‐C may play an important role in corneal lymphangiogensis.     

Lymphatic vessels in vascularized human corneas: immunohistochemical investigation using LYVE-1 and podoplanin

PURPOSE: To determine whether lymphatic vessels exist in vascularized human corneas, by using immunohistochemistry with novel markers for lymphatic endothelium. METHODS: Human corneas exhibiting neovascularization secondary to keratitis, transplant rejection, trauma, and limbal insufficiency (n = 21) were assessed for lymphatic vessel content by conventional transmission electron microscopy and by immunostaining and immunoelectron microscopy with antibodies specific for the lymphatic endothelial markers, lymphatic vessel endothelial hyaluronan receptor (LYVE-1) and the 38-kDa integral membrane glycoprotein podoplanin. In addition, corneas were stained for the lymphangiogenic growth factor VEGF-C, and its receptor VEGFR3 by immunohistochemistry and in situ RNA hybridization, respectively. RESULTS: Thin-walled, erythrocyte-free vessels staining with lymphatic markers (LYVE-1 and podoplanin) were found to constitute 8% of all vessels, to be more common in the early course of neovascularization, to be always associated with blood vessels and stromal inflammatory cells, and to correlate significantly with the degree of corneal hemangiogenesis (r = 0.6; P = 0.005). VEGF-C, VEGFR3, podoplanin, and LYVE-1 colocalized on the endothelial lining of lymphatic vessels. With immunogold labeling, LYVE-1 and podoplanin antigen were found on endothelial cells lining vessels with ultrastructural features of lymph vessels. CONCLUSIONS: Immunohistochemistry with novel lymph-endothelium markers and ultrastructural analyses indicate the existence of lymphatic vessels in vascularized human corneas. Human corneal lymphangiogenesis appears to be correlated with the degree of corneal hemangiogenesis and may at least partially be mediated by VEGF-C and its receptor VEGFR3.     

鼠角膜碱烧伤后新生淋巴管上血管内皮生长因子受体-3的表达和意义

目的探讨鼠角膜碱烧伤后血管内皮生长因子受体-3(VEGFR-3)在新生淋巴管上的表达和意义,进一步证实角膜新生淋巴管的存在。方法在大鼠角膜上制作碱烧伤模型,应用免疫组化法检测第3、5、7天角膜中VEGFR-3蛋白的表达。电镜观测伤后第5、7、10、14天角膜新生淋巴管的情况。结果碱烧伤后,大鼠角膜组织中VEGFR-3表达从第3天开始明显上升,并于第5天达到最高峰,伤后第14天出现新生淋巴管。结论角膜碱烧伤后有新生淋巴管长入,VEGFR-3可能成为抑制角膜新生淋巴管的一个新靶点。     

Topical Ranibizumab inhibits inflammatory corneal hem‐ and lymphangiogenesis

Purpose: Ranibizumab (Lucentis^®) is a Fab‐Fragment of a recombinant, humanized, monoclonal VEGF (anti‐vascular endothelial growth factor) antibody. This study analyzed the ability of topical Ranibizumab to inhibit lymphangiogenesis in addition to hemangiogenesis after acute corneal inflammation in vivo. In addition, the effect of Ranibizumab on the proliferation of human lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) in vitro was studied. Methods: The inhibitory effect of Ranibizumab on LECs and BECs was studied in vitro using a proliferation enzyme‐linked immunosorbent assay (ELISA) assay. To study the in vivo effects of Ranibizumab, the mouse model of suture induced inflammatory corneal neovascularization was used. Study mice received topical Ranibizumab as eye drops. After 1 week excised corneas were stained with LYVE‐1 and CD31. Hemangiogenesis and lymphangiogenesis were analyzed morphometrically by using a semiautomatic method based on the image analyzing program Cell^F. Results: An antiproliferative effect of Ranibizumab was seen in vitro on both human BECs and LECs with a significance of p < 0.0001 and p < 0.0004, respectively. In vivo experiments showed that topical application of Ranibizumab significantly inhibits both hemangiogenesis (p = 0.0026) and lymphangiogenesis (p = 0.0026) in the cornea. Conclusion: Ranibizumab is a potent inhibitor of inflammatory corneal hemangiogenesis and lymphangiogenesis in vivo with a direct inhibitory effect on both endothelial cell types in vitro. This study for the first time demonstrates an inhibitory effect of Ranibizumab on lymphatic vessels which could have a wider range of clinical applications.