Free Radical Status in Retinopathy of Prematurity

Abstract

Retinopathy of prematurity (ROP) is a major cause of blindness in children. Free radicals are implicated in the development of this retinopathy. We studied the role of free radicals in ROP and enrolled 60 preterm neonates at 30-32 weeks age. Thirty neonates predisposed to development of ROP, were placed in study group and 30 normal neonates in control group. Malondialdehyde and antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) were measured in blood spectrophotometrically. Both the groups were followed-up to 40-42 weeks age. Serum MDA levels, erythrocyte SOD and plasma GPX were significantly high in study group at 30-32 weeks as compared to control group. At follow up visit significant increase in MDA level and decrease in SOD and GPX level among the study group was seen. This disturbance in equilibrium of oxidant and antioxidant status initiates an inflammatory process in retinal tissue leading to development of ROP.

Correlation of retinopathy of prematurity with bronchopulmonary dysplasia

“…According to Yang et al [ 31 ] and Seiberth et al [ 32 ], mechanical ventilation increases the severity of ROP. In addition, many researchers have stated they believe free radicals generated as a result of oxygen excess impact the development of ROP and BPD [ 8 , 9 , 33 ]. In cases of ROP and BPD, free oxygen radicals are formed as a result of increased partial oxygen pressure, which is related to the amount of oxygen delivered during oxygen therapy and mechanical ventilation.…”

“…As blood containing hemoglobin A is used for transfusions, HbF is replaced by adult-type hemoglobin (HbA), the properties of which are inverse to HbF; i.e., it can more easily release oxygen to tissues than it can bind to the oxygen. This can lead to the development of hyperoxia in the retina and the formation of oxygen-free radicals, which increases the risk of the development of ROP [ 1 , 4 , 8 , 9 ].…”

“…Retinal hypoxia induces the release of vascular endothelial growth factor (VEGF), which is responsible for neovascularization in the retina [ 1 , 3 , 8 ]. Furthermore, there is excessive activation of macrophages and the level of oxygen free radicals increases [ 8 , 9 ]. Csak et al emphasize the role of genetic factors that may predispose a person to the development of ROP [ 10 ].…”

Oxidative Stress Markers and the Retinopathy of Prematurity

“…Malondialdehyde (MDA) represents one of the final and highly toxic molecules of lipid peroxidation that is easily detectable in the retina [19]. It is a sensitive marker of oxidative stress that, interacting with DNA and proteins, may serve as a potentially mutagenic and atherogenic factor [18,38]. Although MDA constitutes a valuable marker of retinopathy in adults, under different conditions, in the perinatal period, there are only a few observations [38,39].…”

“…It is a sensitive marker of oxidative stress that, interacting with DNA and proteins, may serve as a potentially mutagenic and atherogenic factor [18,38]. Although MDA constitutes a valuable marker of retinopathy in adults, under different conditions, in the perinatal period, there are only a few observations [38,39]. In this regard, Banjac et al examined a cohort of 59 PIs, of whom 18 developed ROP and 41 did not, by assessing MDA blood levels at 33 GA.…”