Analysis of Aqueous and Vitreous Humor

Overview

Clinical Retina research studies often collect aqueous samples in hopes of estimating levels of drug or cytokines in the vitreous. Little is known about how well vitreous and aqueous correlate. This study will collect vitreous and aqueous samples at the same time to evaluate and compare drug and cytokine levels. The overall objective of this study is to evaluate the molecular concentration of growth factors, cytokines and chemokines in human aqueous humor and vitreous samples collected from individuals undergoing pars plana vitrectomy for tractional retinal detachment secondary to proliferative diabetic retinopathy, exudative or tractional retinal detachment secondary to macular degeneration, macular hole or neovascular glaucoma.

This is an open-label, pilot study of intravitreally administered ranibizumab in subjects undergoing pars plana vitrectomy (PPV) to repair tractional retinal detachment secondary to proliferative diabetic retinopathy, exudative serous retinal detachment, macular hole or neovascular glaucoma. Consented, enrolled subjects will be eligible to receive a single open-label intravitreal injection of 0.5 mg ranibizumab administered prior to undergoing PPV if in the Retinal Specialists opinion there could be a benefit to the disease or procedure from ranibizumab therapy. The proposed study will analyze aqueous humor and vitreous samples drawn at the same time during vitrectomy to evaluate the levels of growth factors, cytokines and chemokines from patients undergoing planned pars plana vitrectomy as part of their retinal care. For patients receiving ranibizumab, serum samples will also be collected to assess PK. Patients will be split into three groups based on diagnosis: Group 1: (ranibizumab) proliferative diabetic retinopathy (tractional retinal detachment), macular degeneration with exudative or tractional retinal detachment, macular hole or neovascular glaucoma. Group 1 may receive one injection of intravitreal ranibizumab 0.5mg prior to vitrectomy. The injection will be administered at least 1-14 days prior to vitrectomy. Group 2 will serve as the control group and will not receive intravitreal ranibizumab prior to surgery. Aqueous humor, vitreous and serum samples will be obtained to measure and compare growth factor, cytokine, chemokine levels and ranibizumab levels (if received). Undiluted core vitreous biopsies will be taken at the start of victrectomy. Aproximately 1 mL of undiluted vitreous fluid will be obtained with a closed infusion line and by manual aspiration with cutting on through the vitrectomy probe into a 2.5 mL syringe connected along the aspiration line. The sample will be frozen immediately and stored at -80°C. Approximately 100 microliters of aqueous humor will be collected prior to the start of vitrectomy through anterior chamber paracentesis in the peripheral clear cornea using a 27 gauge needle on a tuberculin microsyringe from the central papillary area. Aqueous is transferred to a vial and placed in liquid nitrogen upon removal from the anterior chamber. Aqueous humor samples are immediately frozen at -80°C within 2 hours of collection until transferred to outside laboratories for further analysis. Serum samples will be obtained from patients in Group 1 at baseline (Day 0) prior to treatment with intravitreal ranibizumab and on the day of surgery prior to the start of vitrectomy. Serum samples will be processed according to Genentech standard operating procedures and samples will be frozen immediately at -80C until analysis is ready to begin.