A review of Pharmacologic Vitreolysis
- Pharmacologic vitreolysis is a promising new therapy to improve vitreoretinal surgery and, ultimately, prevent disease by mitigating the contribution of vitreous to retinopathy.
- Recent studies have demonstrated encouraging results with several enzymatic agents. Both plasmin and
microplasmin are able to induce vitreous liquefaction and a posterior vitreous detachment with a single Intravitreal injection. - If used as a surgical adjunct, these enzymes have the potential to facilitate more complete removal of the vitreous gel, decrease surgical time and reduce intraoperative complications.
- The vitreous is a clear, semisolid gel containing hyaluronic acid interspersed in a framework of parallel collagen fibrils. The outer layer of the vitreous cortex is composed of condensed collagen fibrils that are adherent to the ILM of the retina. The glycoproteins, laminin and fibronectin, bind vitreous collagen fibers between the posterior vitreous cortex and ILM.
- Pharmacologic vitreolysis enzymes break down macromolecules like Hyaluronan.
- Pharmacologic vitreolysis was tested in model solutions of vitreous biochemistry in vitro and postmortem animals models, using noninvasive dynamic light scattering (DLS) to measure vitreous macromolecule diffusion coefficients repeatedly during the experiments and determine vitreous macromolecule sizes before, during, and after treatment.
- The chemical interaction of these fibrils with other molecular components of vitreous is now better understood, enabling the development of a pharmacologic approach to treating vitreoretinal disorders, known as pharmacologic vitreolysis.