Ursodeoxycholic Acid for Rhegmatogenous Retinal Detachment

Retinal detachments consist in a separation of the neuroretina from the retinal pigment epithelium. The most common form is rhegmatogenous retinal detachment (RRD), which occurs as a result of a full-thickness retinal break and the presence of vitreoretinal tractions. Photoreceptor cell death occurs rapidly after RRD and is the ultimate cause of vision loss in these patients. Reattachment of the retina by a surgical procedure allows a recovery of vision. However, the degree of visual recovery differs among patients, despite successful reattachment. This is mainly related to the preoperative visual acuity level, the presence of a macular detachment and its duration. Predicting factors of worse visual acuity are the height of retinal detachment in the macula and the presence of edema, separation, cyst and undulation at the level of the outer nuclear layer showed by optical coherence tomography (OCT). Most patients usually consult with a RRD already involving the macular area after 3 days or more, leading to a worse visual prognostic even with successful surgery. The need for adjuvant neuroprotective agents is then critical to improve photoreceptor survival, functional recovery and subsequent quality of life in patients affected by RRD. Tauroursodeoxycholic acid (TUDCA) is the taurine conjugate of ursodeoxycholic acid (UDCA), a secondary bile acid produced by intestinal bacteria. UDCA was approved by the Food and Drug Administration (FDA) for the treatment of cholestatic liver disease. Both UDCA and TUDCA are potent inhibitors of apoptosis, in part by interfering with the upstream mitochondrial pathway of cell death, inhibiting oxygen-radical production, reducing endoplasmic reticulum (ER) stress, and stabilizing the unfolded protein response (UPR). TUDCA has been proposed as anti-apoptotic agent in several neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer's, Parkinson's, and Huntington's diseases. In certain degenerative retinal disorders, such as retinitis pigmentosa, TUDCA plays an important role in preventing cell death. In an animal model of RRD, systemic treatment by TUDCA has been shown to protect photoreceptors from cell death. The aim of this study is to determine whether detectable levels of UDCA reach the vitreous cavity when administered orally at different time points before surgery for RRD, and to analyze its ocular safety. 20 patients presenting a rhegmatogenous retinal detachment with more than 4 days of duration will be prospectively included. A single dose of ursodeoxycholic acid will be administered orally before surgery at different time-points in 16 subjects. Standard surgery will be performed and ocular samples will be collected during the procedure. Ursodeoxycholic acid treatment will be continued in treated patients during 3 months after surgery.