The Role of Thrombin in Proliferative Vitreoretinopathy

PURPOSE. To determine the role of thrombin in the development of proliferative vitreoretinopathy (PVR). METHODS. Vitreous was collected from patients undergoing a vitrectomy (macular holes and puckers, n ¼ 11 [controls]; retinal detachment without PVR development following vitrectomy, n ¼ 15 [RRD1]; retinal detachment with PVR development within 6 months after vitrectomy, n ¼ 11 [RRD2]; and established PVR, n ¼ 14 [PVR]). Thrombin activity in vitreous was determined using a thrombin-specific chromogenic substrate. ARPE-19 cells were stimulated with 83 diluted vitreous samples in the presence and absence of hirudin. The samples were analyzed at t ¼ 0 and t ¼ 24 hours for the presence of 27 cytokines/ chemokines and growth factors using a multiplex approach. In comparable studies, ARPE-19 cells were stimulated for 2 hours, and mRNA expression levels for CCL2, CXCL8, GMCSF, IL6, and PDGFB were determined by real-time quantitative (RQ)-PCR. RESULTS. Thrombin activity was significantly (P < 0.05) higher in vitreous of the PVR group compared to the other groups. Proliferative vitreoretinopathy vitreous stimulated the production of chemokine (C-C motif) ligand (CCL)2, chemokine (C-X-C motif) ligand (CXCL)8, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and plateletderived growth factor (PDGF)-BB by ARPE-19 to significantly (P < 0.05) higher levels than vitreous from the RRD1 and RRD2 groups. These effects of PVR vitreous were significantly (P < 0.05) reduced by hirudin. These data were confirmed by mRNA studies. CONCLUSIONS. Thrombin activity is increased in vitreous of patients with established PVR and is involved in the activation of proinflammatory and profibrotic pathways in RPE cells. Inhibition of thrombin activity may therefore represent a potential treatment option for proliferative vitreoretinopathy

Ernstige visusdaling door auto-immuunretinopathie

Autoimmune retinopathy (AIR) is a rare disorder which may present as a paraneoplastic syndrome. AIR is associated with the presence of anti-retinal antibodies. These antibodies are assumed to cause damage to the retina, resulting in progressive vision loss. A 74-year-old man visited the ophthalmologist with a serious, progressive loss of vision, without any noteworthy abnormalities at routine ophthalmological examination. The electroretinogram was characteristic of loss of photoreceptor function. Anti-retinal antibodies against recoverin were detected in serum. After referral to an internist on account of a suspected diagnosis of paraneoplastic AIR, the patient was diagnosed with a lung carcinoma, confirming the diagnosis of cancer-associated paraneoplastic AIR. An unexplained loss of vision is highly suggestive of paraneoplastic AIR, even in patients without a known malignancy. Laboratory techniques for the detection of the anti-retinal antibody against recoverin have recently been implemented in the Netherlands, facilitating the diagnosis of AI