Visual outcomes of surgery for stage 4 and 5 retinopathy of prematurity

Retinopathy of prematurity and neonatal gut microbiome: An interview with Professor Dimitra Skondra, Associate Professor of Ophthalmology and Vitreoretinal Surgeon at The University of Chicago (USA)

Retinopathy of prematurity (ROP) is a sight-threatening disorder of the retina affecting neonates of very low birth weight and gestational age, and is characterized by the development of abnormal blood vessel growth. According to Dr Dimitra Skondra, Associate Professor of Ophthalmology and Vitreoretinal Surgeon at the University of Chicago School of Medicine in Chicago, USA, the neonatal gut microbiome may be implicated in the neoangiogenesis process in the neonatal retina and this role may be one of the missing links in the pathogenesis of ROP. The human gut microbiome consists of bacteria, viruses, protozoa and fungi, which colonize the sterile fetal intestine, and differ depending on gestational age, mode of delivery, type of neonatal feeding, the usage of antibiotics and the requirement of neonatal intensive care. To date, it has been related to multiple nutritive, metabolic and immunological functions and has been implicated in the pathogenesis of several human diseases, such as the inflammatory bowel diseases, autoimmune and neurogenerative disorders, metabolic syndrome, cardiovascular diseases and various types of malignant neoplasias. Recent research has proposed that the neonatal gut microbiome profile in high-risk neonates who develop ROP is significantly enriched with Enterobacteriacaea species several weeks prior to the diagnosis of ROP. Further research using animal models is required to prove the causative or secondary role of the microbiome composition in the development and clinical course of ROP. If this role is proven, the gut microbiome could then be a target of intervention for personalized medicine in the prevention and therapeutic management of ROP in neonates.

Pigment Epithelium-Derived Factor Inhibits Oxygen-Induced Retinal Neovascularization in a Murine Model

BACKGROUND

The inhibitory effects of pigment epithelium-derived factor (PEDF) on retinal neovascularization were observed in a murine model of oxygen-induced retinopathy.

METHODS

PEDF was administered via intravitreal injection into the right eye of mice subjected to hyperoxia. The proliferative neovascular response was assessed by evaluating the vascular pattern in retinal flat-mounts and quantified by counting the number of new vascular cell nuclei extending into the internal limiting membrane. Retinas were stained for vascular endothelial growth factor (VEGF), PEDF, and CD31 with immunohistochemical method.

RESULTS

The effect of PEDF on retinal neovascularization is related to the postnatal age at the time of injection and the number of injections. The injection of 2 µg of PEDF at postnatal day 12 (P12) and P14 markedly inhibited retinal neovascularization.

CONCLUSION

Locally administered PEDF is a potentially effective vascular inhibitory factor for the treatment and prevention of retinopathy of prematurity.

Time at treatment of severe retinopathy of prematurity in China: recommendations for guidelines in more mature infants

PURPOSE

To investigate the postmenstrual (PMA) age at treatment of severe retinopathy of prematurity (i.e. Type 1 prethreshold or threshold) in infants in a tertiary referral center in China.

PRINCIPAL FINDINGS

76.6% (359/469) of infants were treated for threshold disease. 67.5% (317/469) of infants had a birth weight (BW) of 1250 g or above and almost 30% (126) had a gestational age (GA) of 32 weeks or above. There was little difference in the characteristics of infants treated for Type 1 prethreshold or threshold ROP. After controlling for GA, PMA age at treatment was highest in infants with BW ≥2000 g (mean PMA 40.3±4.4 weeks, p<0.001); after controlling for BW, higher GA was associated with higher PMA at treatment (mean PMA 41.5 weeks for gestational age >34 weeks, p<0.001). For every three weeks increase in GA there was a two-week increase in PMA at treatment (R2 = 0.20, p<0.001). The time at treatment of Type 1 prethreshold disease was similar to that for threshold disease i.e. chronological age 5.6∓7.4 weeks, or PMA 34.1∓40.2 weeks but the lower end of the 95% confidence interval for chronological age for Type 1 prethreshold disease among infants with BW ≥2000 g was 3.7 weeks (i.e. before the recommended interval of 4∓6 weeks after birth).

SIGNIFICANCE

The Chinese guidelines regarding timing of the first examination are appropriate for infants with BW <2000 g, but more mature infants should be examined a little earlier, at 3 weeks after birth, in order to detect Type 1 prethreshold disease which has a better prognosis than threshold.