ABSTRACT
As metaloproteinases (MMPs) são enzimas colagenolítcas endó- genas, capazes de degradar as fibrilas de colágeno presentes na dentina, gerando falhas da interface adesiva. Foram propostos agentes de cross-linking para diminuir essa degradação. O objetivo desta revisão de literatura foi analisar a ação de diferentes agentes de cross-linking sobre as MMPs. A seleção dos artigos foi realizada por meio de uma busca na base de dados PubMed/MEDLINE. A amostra final foi composta por 40 estudos publicados entre 2018 e 2010. Os estudos atuais apresentaram os agentes de cros-s-linking (cabordiimida, glutaraldeído, proantocianidina, riboflavina/ UV-A e quitosana) com vantagens como inespecificidade em relação aos tipos de MMPs, aumento da resistência da fibra colágena e possibilidade de bloquear o sítio de clivagem da enzima. Ob- servou-se que a cabordiimida, riboflavina/UV-A, o glutaraldeído, a proantocianidina e a quitosana apresentaram resultados positivos na diminuição da degradação da interface adesiva. A carbodiimida e riboflavina/UV-A não são citotóxicas, diferentemente do glutaraldeído. A proantocianidina, quando incorporada no adesivo, apesar de interferir na polimerização dos monômeros adesivos, pode ser efetiva quando utilizada incorporada ao condicionamen- to ácido. A quitosana é capaz de reforçar as fibrilas de colágeno. Assim, foi possível conhecer mais sobre a ação dos agentes de cross-linking disponíveis. No entanto, há necessidade de mais pesquisas sobre esses agentes.
Metalloproteases are endogenous collagenolytic enzymes, capable of degrading the collagen fibrils present in the dentin, producing adhesive interface failures. Cross-linking agents has been proposed to reduce this degradation. The aim of this literature review was to analyze the action of different cross-linking agents on MMPs. The search was conducted in the PubMed database. The final sample consisted of 40 studies published between 2018 and 2010. Current studies have shown cross-linking agents (cabordiimide, glutaraldehyde, proanthocyanidin, riboflavin / UV-A and chitosan) present some advantages as non- specificity to type of MMPs, collagen fiber's toughness development and prevent bonding to the cleavage site of the enzyme. For this reason, it is necessary to know the action of the available cross-linking agents. It was observed that Cabordiimide, riboflavin / UV-A, glutaraldehyde, proanthocyanidin and chitosan presented positive results in reducing degradation of the adhesive interface. Carbodiimide and riboflavin / UV-A are non-cytotoxic, unlike glutaraldehyde. Proanthocyanidin incorporated into the adhesive interferes with the polymerization of the adhesive monomers. Chitosan is able to reinforce collagen fibrils. Thus, it was possible to know more about the action of the available cross-linking agents. However, there is a need for more research on these agents.
ABSTRACT
We describe a case of early post-LASIK ectasia detected in the first 6 months after surgery. The patient was treated by means of intrastromal corneal crosslinking under the flap, without de-epithelialization, which resulted in a positive outcome. At the time of writing, 2 years after the procedure, the patient remained free of progression.
Descrevemos um caso de ectasia de córnea precoce após cirurgia de LASIK, detectado no primeiro semestre pós-operatório. Nós optamos tratar este paciente com "crosslinking" embaixo do "flap" , sem desepitelização com bons resultados. A paciente permaneceu sem progressão da ectasia até o momento atual, dois anos após o procedimento.
Subject(s)
Adult , Female , Humans , Corneal Diseases/drug therapy , Corneal Diseases/etiology , Keratomileusis, Laser In Situ/adverse effects , Postoperative Complications/drug therapy , Postoperative Complications/etiology , Corneal Topography , Cornea/pathology , Cornea/surgery , Dilatation, Pathologic/drug therapy , Dilatation, Pathologic/etiology , Photosensitizing Agents/administration & dosage , Riboflavin/administration & dosage , Time Factors , Treatment Outcome , Visual AcuityABSTRACT
Background It is determined that riboflavin/ultraviolet A (UVA)-induced corneal collagen crosslinking is able to increase resistance of cornea against enzymatic digestion and has antimicrobial efficacy for various kinds of bacteria in vitro.However,its in vivo study is less now.Objective This study aimed to evaluate the efficacy of iontophoresis-mediated corneal collagen crosslinking combined with or without drugs for Staphylococcus aureus keratitis.Methods Bacterial keratitis models were induced by the interstromaly injection of Staphylococcus aureus suspension with concentration 2× 109/ml in the right eyes of 40 rabbits,and then the rabbits were randomly classified into the model group,gatifloxacin eye drops group,riboflavin/UVA corneal crosslinking group and drugs+ crosslinking group.The smearing of corneal surface was performed for the identification of bacteria 24 hours after injection.Iontophoresis-mediated riboflavin/UVA crosslinking was applied on the eyes of the riboflavin/UVA corneal crosslinking group and drugs+crosslinking group,and gatifloxacin eye drops was topically used 7 times per day on the eyes of the gatifloxacin eye drops group and drugs+crosslinking group.The corneal inflammation was examined and graded under the slit lamp biomicroscope before and after treatment.Ocular anterior segment optical coherence tomography(AS-OCT),corneal histopathology and ultrastructure were examined 14 days after treatment.The living environment of the experimental animals was maintained at 21 ℃ with a 12-hour light and dark cycle.Animals used in this study were treated in accordance with the Weifang Medical College Animal Experimentation Ethic Committee (AEEC) guidelines.The study protocol was approved by the AEEC.Results Corneal inflammation and ulcer were observed,but no significant difference was found in the inflammatory grade among the 4 groups 24 hours after injection (x2=0.293,P＞0.05).In the 14th day after injection,the corneal ulcer area was smaller and corneal edema was milder in the drugs+crosslinking group compared with the model group,gatifloxacin eye drops group and riboflavin/ UVA corneal crosslinking group,showing a significant difference in the inflammatory grade among them (x2 =38.710,P＜0.001).The cornea thickness values of ulcer zone were (428.1 ± 146.2) μm on the 14th postinjected day in the drugs+crosslinking group,which was evidently higher than those in the model group,gatifloxacin eye drops group and riboflavin/UVA corneal crosslinking group,with a significant difference among the 4 groups (F =8.310,P＜0.001).A lower degree of destruction of cornea collagen and less inflammatory cells were seen in the cornea tissue of the drugs+ crosslinking group by haematoxylin and eosin staining in comparison with other 3 groups,and normal keratocytes were much more in the drugs + crosslinking group than those in other treated groups.Conclusions Iontophoresismediated corneal collagen crosslinking can alleviate Staphylococcus aureus keratitis.The combination of crosslinking with drugs has a better effectiveness than the administration of gatifloxacin eye drops only or riboflavin/UVA corneal crosslinking only.