Homocysteine influences the human keratocytes cell cycle

BACKGROUND: Homocysteine (Hcy), a metabolic intermediate, is a sulfur-containing amino acid not present in the structure of proteins. It has been shown that high Hcy levels via oxidative stress, induced inflammation, and vessel dysfunction may affect the functioning of tissues, including the structures that form the eye, among others keratocytes. The visual disturbance caused by high levels of Hcy may also be associated with disturbed cell proliferation resulting from the effect of this amino acid on the cell cycle. The goal was to analyse the influence of Hcy on the keratocytes and to find out in which phase of the cell cycle its course is disturbed by this amino acid. MATERIALS AND METHODS: A normal human keratocytes (HK) cell line was used in the study. May-Grünwald-Giemsa (MGG) staining for morphology visualization and cytometric cell cycle analysis were performed. RESULTS: Hcy does not affect the G1 phase of the cycle, while it regulates the S and G2 phases. Changes in the amount of the sub-G1 population  indicative of a pro-apoptotic effect of Hcy on keratocytes were detected. The form of the Hcy administered (L stereoisomer or DL racemic mixture) and the amino acid concentration were also important. CONCLUSIONS: Homocysteine influences the keratocyte cell cycle. The change occurs at the stage of the G1-S transition, which suggests a decreasing level of cells in the S phase and an increasing level in the G2 phase. The long-term influence of Hcy on keratocytes may affect keratocytes proliferation and possible cornea regeneration

Outcomes of Vitrectomy in Pediatric Retinal Detachment with Proliferative Vitreoretinopathy

Aim. To report outcomes of pars plana vitrectomy (PPV) in pediatric retinal detachment (RD) with proliferative vitreoretinopathy (PVR), complications, factors influencing the final anatomical and functional results. Methods. Retrospective consecutive case series of 14 eyes. Average postoperative follow-up period was 34 months. Results. Mean age of patients was 10 years; eleven patients (79%) were males. The most common etiology was trauma (57%), the second—myopia (36%) and one case of uveitis (7%). At the day of presentation, the best-corrected visual acuity (BCVA) was worse than hand motion (50%); macula was detached in 86% of cases. Simultaneous PPV and phacoemulsification with intraocular lens (IOL) implantation were performed in 12 cases (86%). The most common endotamponade during PPV was silicone oil (93%). Anatomic reattachment was accomplished in 86% of cases. Final BCVA was equal or better than 0.1 in 50% of patients. The postoperative complications were found in 5 eyes (36%). Conclusion. Complete PPV was allowed for anatomically reattached retina and preserved vision in pediatric complex RD with PVR. However, visual outcomes were not satisfactory. Preserving vision in children with RD is of great importance for their future motor and intellectual development. This trial is registered with ClinicalTrials.gov Identifier: NCT03208205