ABSTRACT
Abstract Purpose: To establish and compare protocols of alkaline cauterization for inducing corneal angiogenesis in murine models. Methods: Twenty-four adult Wistar rats were distributed into four groups (G1, G2, G3, and G4). The right eye cornea from each rat was cauterized using filter paper (3 mm), soaked in a solution of silver and potassium nitrates (3:1). Cauterization times were 10 (G1 and G4), or 20 seconds (G2 and G3). Cauterized corneas were washed with Ringer's lactate solution. The filter paper was either removed before washing (G1 and G2), or kept on the corneas (G3 and G4). Corneas were photographed at multiple time points (2, 4, 6, 8, 11, 13, and 15 days after the procedure), and neovascularization parameters were assayed. Results: Neovascularization was observed in 66% of G1 corneas, and 100% of G2, G3, and G4 corneas. On day 15, G1 corneas showed smaller vascularized areas (12.63 ± 12.59%) compared to those in the G3 (41.95 ± 17.32%) and G4 (33 ± 11.74%) (P < 0.05) groups. Conclusions: The silver and potassium nitrate solution effectively induced corneal angiogenesis. The G2, G3, and G4 protocols showed excellent reproducibility, and induced vascularization in 100% of corneas.
Subject(s)
Animals , Male , Cautery/methods , Corneal Neovascularization/etiology , Potassium Compounds , Disease Models, Animal , Neovascularization, Pathologic/etiology , Nitrates , Reference Values , Time Factors , Reproducibility of Results , Rats, Wistar , Cornea/surgery , Cornea/blood supplyABSTRACT
RESUMO Objetivo: Estudar botões corneanos humanos com linfangiogênese através do exame histopatológico, juntamente com os enxertos de seus transplantes anteriores e posteriores, avaliando os intervalos de tempo para sucessivas cirurgias. Métodos: Estudo descritivo, observacional, longitudinal de botões corneanos humanos com linfangiogênese, juntamente com seus transplantes anteriores e posteriores. Os tecidos foram provenientes de ceratoplastia penetrante no período compreendido entre os anos 2006 e 2013. Após revisão de prontuários em que foram obtidas principalmente as datas das cirurgias, construímos uma tábua de sobrevivência a partir da qual os intervalos de tempo para retransplante foram calculados. Resultados: Entre 89 casos de linfangiogênese corneana, foram incluídos apenas aqueles 22 que possuíam registros no prontuário de transplantes anteriores ou posteriores. Nos casos que apresentavam como provável etiologia do retransplante a linfangiogênese, isolada ou associada à hemangiogênese (grupos pré-linfangiogênese/linfangiogênese e interlinfangiogênese), foram encontrados intervalos de tempo para retransplante menores (7 e 3 meses, respectivamente) que aquele encontrado no grupo linfangiogênese/pós-linfangiogênese que apresentava outras etiologias prováveis para os retransplantes (11,31 meses). Casos que apresentavam como etiologia provável do retransplante a linfangiogênese isolada apresentaram um intervalo para retransplante (3 meses) ainda menor que aquele encontrado nos casos em que a etiologia provável era a linfangiogênese associada à hemangiogênese (7,80 meses). Conclusão: Linfangiogênese, isolada ou associada à hemangiogênese, foi encontrada nos enxertos corneanos humanos estudados que evoluíram para retransplante em pequenos intervalos de tempo. Esse achado nos leva a sugerir um possível papel para os vasos linfáticos na redução do tempo de sobrevida dos enxertos corneanos humanos.
ABSTRACT Objective: To study human corneal buttons with lymphangiogenesis through histopathological examination, together with the grafts of their preceding and subsequent transplantations, evaluating the time intervals for successive surgeries Methods: A descriptive, observational and longitudinal study of human corneal buttons that have lymphatic vessels, together with its preceding and subsequent transplants. Tissues were obtained from penetrating keratoplasty in the period between the years 2006 and 2013. After a medical records review in which information on the dates of the surgeries were mainly obtained, we built a survival table from which the time intervals for retransplantation were calculated. Results: Among 89 cases of corneal lymphangiogenesis, we included only those 22, which had previous or subsequent transplantations records in medical records. In cases where the probable regrafting etiology were lymphangiogenesis, alone or combined with hemangiogenesis (pre-lymphangiogenesis/lymphangiogenesis and interlymphangiogenesis groups), time intervals for retransplantation were found to be minor (7 and 3 months, respectively) than that found in lymphangiogenesis/post-lymphangiogenesis group that had other probable etiologies for retransplantations (11.31 months). Cases that had isolated lymphangiogenesis as probable etiology of retransplantation showed an interval time for retransplantation (3 months) lower than that found in cases in which the probable etiology was lymphangiogenesis associated with hemangiogenesis (7.80 months). Conclusion: Lymphangiogenesis, alone or combined with hemangiogenesis, was found in human corneal grafts studied that have evolved to regraft in small time intervals. This finding leads us to suggest a possible role for the lymphatic vessels in reducing the human corneal grafts survival time.
Subject(s)
Humans , Male , Female , Adult , Reoperation , Corneal Transplantation , Keratoplasty, Penetrating , Corneal Neovascularization/pathology , Cornea/pathology , Lymphangiogenesis/physiology , Cornea/blood supply , Corneal Diseases/pathology , Lymphatic VesselsABSTRACT
Purpose: To compare the effects of bevacizumab applied either subconjunctivally or topically, in a rat model of corneal neovascularization induced by alkali burn. Methods: The right corneas of 24 Wistar-Albino rats were cauterized with silver nitrate sticks. The rats were divided randomly and equally into three groups: no treatment control (n=8), subconjunctival bevacizumab treatment (n=8), and topical bevacizumab treatment (n=8). Immediately following cauterization, the subconjunctival group was treated with a 0.05 ml (1.25 mg) bevacizumab subconjunctival injection. The topical group was treated with 10 mg/ml bevacizumab twice daily, and the control group received subconjunctival saline injections twice daily. The burn stimulus and neovascularization scores were evaluated using a technique previously described by Mahoney and Waterbury. Digital photographs were obtained before the eyes were enucleated and corneal sections were then analyzed by histopathology. Results: The mean burn stimulus score was 1.86 ± 0.6 and there was no statistical difference between the groups (p=0.730). The mean neovascularization scores in the subconjunctival and topical bevacizumab groups were statistically lower than the control group (p<0.05). The mean percentage area of corneal neovascularization was 82.5 ± 22.1 in the control group, 42.7 ± 15.0 in the subconjunctival group, and 55.8 ± 18.2 in the topical group. The differences between the control and treatment groups were statistically significant (p<0.05). Histopathology showed that the treatment groups presented less neovascularization, inflammation, and fibroblast activity than the control group (p<0.05). Conclusions: This study demonstrates that both subconjunctival and topical administrations of bevacizumab inhibit corneal neovascularization and decrease inflammation and fibroblast activity in a rat model of corneal neovascularization induced by alkali burn. .
Objetivo: Comparar o efeito de bevacizumab aplicado subconjuntival e topicamente em um modelo de neovascularização de córnea de ratos induzida por queimadura alcalina. Métodos: Córneas direitas de 24 ratos Wistar-Albino foram cauterizados por nitrato de prata. Os indivíduos foram divididos aleatoriamente e igualmente em três grupos: controle (n=8), o bevacizumab subconjuntival (n=8), o bevacizumab tópico (n=8). Imediatamente após a cauterização, 0,05 ml (1,25 mg) de bevacizumab foi injetado no grupo subconjuntival. Grupo tópico foi inculcado com 10 mg/ml de bevacizumab duas vezes por dia. O grupo controle recebeu solução salina normal, topicamente, duas vezes ao dia. A graduação do estímulo da queimadura e a graduação da neovascularização foram avaliados utilizando a técnica descrita por Mahoney e Waterbury. Fotografias digitais foram obtidas dos olhos serem enucleados. Seções da córnea foram analisadas por histopatologia. Resultados: A média da graduação do estímulo da queimadura foi de 1,86 ± 0,6 e não houve diferença estatisticamente entre os grupos (p=0,730). As médias das graduações da neovascularização no grupo bevacizumab subconjuntival e no grupo bevacizumab tópico foram estatisticamente menores do que o grupo controle (p<0,05). A percentagem média de área de neovascularização da córnea foi de 82,5 ± 22,1 no grupo controle, 42,7 ± 15,0 no grupo subconjuntival e 55,8 ± 18,2 no grupo tópico. As diferenças entre os grupos de tratamento e grupo de controlo foram estatisticamente significativos (p<0,05). A histopatologia mostrou que os grupos de tratamento apresentavam menos neovascularização, inflamação e atividade de fibroblastos do que o grupo controle (p<0,05). ...
Subject(s)
Animals , Male , Rats , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal/administration & dosage , Corneal Neovascularization/drug therapy , Cornea/blood supply , Cornea/pathology , Corneal Neovascularization/chemically induced , Disease Models, Animal , Injections, Intraocular , Random Allocation , Rats, WistarABSTRACT
PURPOSE: To evaluate the corneal vascularization (CV) and the clinical aspects induced by interlamellar graft with native (NCM) and anionic (ACM) collagen membranes in rabbits corneas. METHODS: An interlamellar graft with a 0.25 x 0.25 cm NCM (group 1) or ACM (group 2) fragment was performed in the right eye (treated eye). In the left eye, an estromal tunnel was done (control eye). Sixteen rabbits were used, and they were subdivided into two experimental groups of eight animals each. The clinical evaluation was performed at the 1st, 3rd, 7th, 15th and 30th postoperative days. Corneal vascularization analysis was performed after 30 days by the Images Analizator System Leica Qwin-550®. RESULTS: After 7 days, corneal vascularization was observed at about 2.25 ± 0.71 mm (NCM) and at about 1.0 ± 1.69 mm (ACM), respectively, from the limbus in direction to the central cornea. After 15 days, CV increased in both groups (5.25 ± 1.03 mm - NCM; 2.0 ± 2.39 mm - ACM) and then progressively decreased until day 30 (2.25 ± 2.10 mm - NCM; 0.75 ± 2.12 mm - ACM). The statistical analysis indicated that the averages of the distances from the limb vessels to the grafts observed after 7 and 15 days had not differed statistically (p=0.17), and after 15 and 30 postoperative days had a tendency to differ statistically (p=0.09). The control eyes did not present any changes. CONCLUSION: The interlamellar graft with native and anionic collagen membranes induced corneal vascularization when applied to rabbit corneas, but anionic collagen membrane induced a smaller corneal vascularization when compared to native collagen membrane. Although further studies are required, the results found in this study demonstrated the usefulness of interlamellar graft with native and anionic collagen membranes in keratoplasties. These membranes consists in one more graft option for the surgical treatment of corneal repair in rabbits and others animals, when other forms of medical...
OBJETIVO: Avaliar os aspectos clínicos e vascularização corneal (VC) induzida pelo enxerto interlamelar das membranas de colágeno nativo (MCN) e de colágeno aniônico (MCA) em córneas de coelhos. MÉTODOS: Um fragmento com 0,25 x 0,25 cm de MCN (grupo 1) e MCA (grupo 2) foi realizado no olho direito (olho tratado) por enxertia interlamelar. No olho esquerdo (olho controle) foi realizado apenas um túnel estromal. No olho direito (olho controle) foi realizado apenas um túnel estromal. Dezesseis coelhos foram utilizados e foram divididos em dois grupos experimentais composto por oito animais cada. A avaliação clínica foi realizada aos 1, 3, 7, 15 e 30 dias de pós-operatório. A análise da vascularização corneal foi realizada após 30 dias pelo Sistema de analisador de imagens Leica Qwin-550®. RESULTADOS: Após 7 dias, a vascularização corneal do limbo em direção central da córnea observada foi de 2,25 ± 0,71 mm (MCN) e 1,0 ± 1,69 mm (ACM), respectivamente. Após 15 dias a vascularização corneal aumentou em ambos os grupos (5,25 ± 1,03 mm - MCN; 2,0 ± 2,39 mm - MCA), diminuindo até o 30º dia (2,25 ± 2,10 mm - MCN; 0,75 ± 2,12 mm - MCA). A análise estatística indicou que as médias das distâncias dos vasos do limbo em direção ao enxerto observadas após 7 e 15 dias não diferiram estatisticamente (p=0,17), e 15 e 30 dias de pós-operatório houve tendência a diferir estatisticamente (p=0,09). Os olhos controles não apresentaram nenhuma alteração. CONCLUSÃO: As membranas de colágeno nativo e de colágeno aniônico induzem a vascularização corneal quando aplicadas na córnea de coelhos por meio de enxertia interlamelar, mas membrana de colágeno ativo induz a pequena vascularização corneal quando comparada à membrana de colágeno aniônico. Embora estudos adicionais sejam necessários, os resultados encontrados no presente estudo demonstraram que as membranas de CN e CA possam ser úteis em ceratoplastias. Estas membranas consistem em mais uma opção de enxerto...
Subject(s)
Animals , Rabbits , Collagen , Cornea/blood supply , Corneal Transplantation/methods , Membranes, Artificial , Neovascularization, Physiologic , Analysis of Variance , Biocompatible Materials/chemistry , Models, AnimalABSTRACT
To study corneal lymphangiogenesis after corneal transplantation, corneal allogenic transplantation models were established in rats. 8 female Wister rats were used as donors, and 16 Sprague Dawley (SD) rats were used as recipients and 2 SD served as controls. Corneal lymphangiogenesis and hemangiogenesis was examined by electron microscopy 1 and 2 weeks after corneal penetrating transplantation, and the expression of lymphatic vessel endothelial receptor (LYVE-1) was examined 1, 3, 7, 14 days after the transplantation respectively. In addition, 19 allograft failed human corneas were examined by 5'-nase-alkaline phosphatase (5'-NA-ALP) double-enzyme-histochemistry staining to detect corneal lymphangiogenesis and hemangiogenesis. By immunohistochemistry for LYVE-1, it was found that blown lymphatics were localized in the stroma 3 days after the corneal transplantation. With electron microscopy, new lymphatic vessels and blood vessels were found 1 and 2 weeks after the corneal transplantation. By 5'-NA-ALP enzyme-histochemistry, corneal hemangiogenesis was found in all allograft failed human corneas and 5 of 19 (26.3 %) cases had developed corneal lymphangiogenesis. It is concluded that corneal lymphangiogenesis is present after corneal transplantation, which may play an important role in allograft rejection.
Subject(s)
Cornea/blood supply , Cornea/chemistry , Cornea/ultrastructure , Corneal Neovascularization/etiology , Corneal Neovascularization/metabolism , Corneal Transplantation/adverse effects , Corneal Transplantation/methods , Immunohistochemistry , Lymphangiogenesis , Microscopy, Electron , Rats, Sprague-Dawley , Rats, Wistar , Vesicular Transport Proteins/biosynthesisABSTRACT
OBJETIVO: Estabelecer um modelo de angiogênese em córnea de coelho, induzida pela cauterização pontual com hidróxido de sódio. MÉTODOS: Seis coelhos foram submetidos a uma cauterização pontual na córnea direita, utilizando-se uma peça circular (3 mm) de papel filtro, previamente embebida em NaOH 1 M, a qual foi posicionada a 1mm do limbo superior durante 2 minutos. Os animais foram avaliados nos dias 3, 6, 9, 12, 15, 18 e 21, após a cauterização. A quantificação da angiogênese foi realizada de acordo com 4 métodos: comprimento vascular radial (V), índice angiogênico (I), área do triângulo (T) e do setor de coroa circular (S), ambas medidas aproximadas da área de neovascularização. RESULTADOS: A análise das curvas dos quantificadores revelou que a resposta angiogênica seguiu um padrão bifásico: crescente até o 12º dia (proliferação), estável do 12º ao 21º dia (maturação). Comportamento também observado na taxa de crescimento vascular, que foi 16 vezes maior no período de 0 a 12 dias do que no intervalo entre o 12º e o 21º dia. Foi constatada, ainda, uma correlação linear positiva estatisticamente significante entre os 4 quantificadores de angiogênese. CONCLUSAO: A cauterização alcalina pontual da córnea de coelho induz e mantém neovascularização corneana, podendo, assim, ser utilizada como modelo de angiogênese.
Subject(s)
Animals , Male , Female , Rabbits , Cornea/blood supply , Cornea/pathology , Sodium Hydroxide/administration & dosage , Inflammation/etiology , Cautery , Inflammation/pathology , Neovascularization, PathologicABSTRACT
This study was performed to evaluate the effects of nerve growth factor (NGF) upon angiogenesis in the rat cornea, to examine its possible application as an alternative angiogenic inducer and to provide basic data for further studies. Angiogenesis was induced by cornea micropocket assay, as previously described. Eight of thirty two eyes of Sprague-Dawley rats were randomly assigned to one of four groups, namely, a non-NGF group (Group 0), a 0.5 ng of NGF group (Group 0.5), a 1.0 ng of NGF group (Group 1.0) and a 5.0 ng of NGF group (Group 5.0). Pellets made of poly-2-hydroxylethylmethacrylate and sucralfate were implanted into the corneal stroma no closer than 1 mm from the limbus. After the implantation, the number of new vessels, vessel length and circumferential neovascularization were examined daily under the surgical microscope over a period of 7 days. The area of neovascularization was determined using a mathematical formula. Although new vessels in Group 0 and Group 0.5 were first observed at day 5, those of Groups 1.0 and 5.0 were first noted on days 4 and 3, respectively. However, the growth rates of new vessels in Groups 1.0 and 5.0 were higher than those of Groups 0 and 0.5 with the passage of time. The number, length, circumferential neovascularization and areas covered by the vessels in Groups 1.0 and 5.0 were significantly more than in Group 0 and Group 0.5 (p<0.05). This study showed that NGF had a dose-dependent angiogenic effects on the rat cornea and that the minimal effective dose of NGF was 1.0 ng per cornea. Also, it showed that NGF would be useful in angiogenic studies as an alternative angiogenic inducer.
Subject(s)
Animals , Female , Male , Rats , Angiogenesis Inducing Agents/toxicity , Cornea/blood supply , Corneal Neovascularization/chemically induced , Dose-Response Relationship, Drug , Nerve Growth Factor/toxicity , Random Allocation , Rats, Sprague-DawleyABSTRACT
A angiogênese é um processo de múltiplos degraus que conduz a formação de novos vasos sangüíneos a partir de capilares preexistentes e que participa em diversos processos fisiológicos e patológicos incluindo o crescimento tumoral e de metástases. Vários métodos têm sido desenvolvidos para estudar a angiogênese. A técnica de indução de vascularização na córnea do coelho foi uma das primeiras a serem desenvolvidas pelo grupo de Gimbrone e colaboradores. O principal objetivo deste trabalho foi descrever a técnica de indução de angiogênese na córnea do coelho, através do implante cirúrgico de "pellets" de polimetilmetacrilato (PMMA) contendo fator básico de crescimento fibroblástico (FCFb). Um "pellet" contendo 0.1 mig de FCFb foi implantado em uma das córneas e outro, sem FCFb, na córnea contralateral, como controle. A atividade angiogênica foi expressa por um índice, resultado da contagem do número de vasos e da medição de seu comprimento em milímetros. Os resultados mostraram que o FCFb induz crescimento vascular significativo a partir do sexto dia após o implante do "pellet" com atividade máxima no 15º dia. O PMMA sem FCFb não estimulou significativamente a vascularização. Esta técnica fornece uma nova opção de modelo para o estudo da biologia da angiogênese e para avaliação de drogas antiangiogênicas, usando "pellets" de polimetilmetacrilato (PMMA).
Subject(s)
Animals , Rabbits , Male , Female , Cornea/blood supply , Neovascularization, Physiologic , Polymethyl Methacrylate/pharmacology , Drug Implants , Fibroblast Growth Factors/pharmacologyABSTRACT
Angiostatin is a potent angiogenesis inhibitor that is composed of the first four kringles of plasminogen fragment. Angiostatin with one less kringle molecule (kringle 1 to 3) was recently demonstrated to be an effective angiogenic inhibitor. To determine whether recombinant plasminogen kringle 1-3 (rPK1-3) can inhibit the corneal neovascularization induced by potent angiogenic factors; angiogenin, bFGF, or VEGF, hydron polymer discs each containing 2.0 microg of angiogenin, 500 ng of bFGF, or 500 ng of VEGF respectively were implanted into the corneal stroma of 138 rabbit eyes, and then discs each containing 10 microg, 12.5 microg, 20 microg or 30 microg of rPK1-3 were implanted randomly. Discs containing phosphate buffered saline were also implanted as a control. The angiogenesis score on number and length of newly formed vessels on the each of the rabbit's cornea were recorded daily by two observers (blinded). The treated corneas were also examined histologically. Recombinant PK1-3 treated corneas showed less neovascularization induced by all angiogenic factors (p < 0.05). and the extent of inhibition of neovascularization was proportional to the concentration of rPK1-3 (p < 0.05). Histologic examination showed leukocyte infiltration into the corneal stroma on the PBS treated eyes whereas rPK1-3 treated eyes showed only traces of leukocytes. These results of the effective rPK1-3 inhibition of corneal neovascularization induced by angiogenin, bFGF, or VEGF suggest that this angiostatin related fragment, rPK1-3, may be useful in the treatment of various neovascular diseases. Copyright 2000 Academic Press.
Subject(s)
Chick Embryo , Rabbits , Angiogenesis Inhibitors/pharmacology , Angiogenesis Inhibitors/genetics , Animals , Chorion/drug effects , Chorion/blood supply , Cornea/pathology , Cornea/drug effects , Cornea/blood supply , Endothelial Growth Factors/pharmacology , Fibroblast Growth Factor 2/pharmacology , Kringles/genetics , Lymphokines/pharmacology , Microscopy/methods , Neovascularization, Pathologic/drug therapy , Plasminogen/pharmacology , Plasminogen/genetics , Recombinant Proteins/pharmacology , Recombinant Proteins/genetics , Ribonuclease, Pancreatic/pharmacologyABSTRACT
The healing of graft and visual results were compared in 21 vascularized and 29 non-vascularized corneal lesion. The healing and visual results were better in those cornea which were non-vascularized.
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Cornea/blood supply , Corneal Diseases/physiopathology , Female , Graft Survival , Humans , Keratoplasty, Penetrating , Male , Middle Aged , Vascular Patency , Wound HealingABSTRACT
O A. relata auto-observaçäo de amaurosis fugax e hemorragia no vítreo, proveniente de sangramento de vasos episclerais na cicatriz de facectomia realizada 12 anos antes