Vascularization is essential for tissue development and in restoration of tissue integrity after an ischemic injury. In studies of vascularization, the focus has largely been placed on vascular endothelial growth factor (VEGF), yet other factors may also orchestrate this process. Here we show that succinate accumulates in the hypoxic retina of rodents and, via its cognate receptor G protein-coupled receptor-91 (GPR91), is a potent mediator of vessel growth in the settings of both normal retinal development and proliferative ischemic retinopathy. The effects of GPR91 are mediated by retinal ganglion neurons (RGCs), which, in response to increased succinate levels, regulate the production of numerous angiogenic factors including VEGF. Accordingly, succinate did not have proangiogenic effects in RGC-deficient rats. Our observations show a pathway of metabolite signaling where succinate, acting through GPR91, governs retinal angiogenesis and show the propensity of RGCs to act as sensors of ischemic stress. These findings provide a new therapeutic target for modulating revascularization.

Retinopathy of prematurity (ROP) is a major complication of preterm birth. It encompasses a spectrum of pathologies that affect vision, from mild disease that resolves spontaneously to severe disease that causes retinal detachment and subsequent blindness. The pathologies are characterized by an arrest in normal retinal vascular development associated with microvascular degeneration. The resulting ischemia and retinal hypoxia lead to excessive abnormal compensatory blood vessel growth. However, this neovascularization can lead to fibrous scar formation and culminate in retinal detachment. Present therapeutic modalities to limit the adverse consequences of aberrant neovascularization are invasive and/or tissue-destructive. In this Review, we discuss current concepts on retinal microvascular degeneration, neovascularization, and available treatments, as well as present future perspectives toward more profound elucidation of the pathogenesis of ROP.Retinopathy of prematurity (ROP) is the major ocular disorder of the neonate (1, 2) and the dominant cause of severe visual impairment in childhood in North America and Europe. ROP is associated with significant sequelae, the most serious being retinal detachment, which results in blindness. However, even milder forms of ROP increase the incidence of pathologies that negatively impact visual acuity, for example, ametropias, refractive errors that reduce visual acuity; strabismus, a condition in which the eyes are not properly aligned, preventing proper binocular vision and adversely affecting depth perception; and disorders of color discrimination (3-6). ROP proceeds following an initial phase of degeneration of the retinal microvasculature (vasoobliteration) (7,8) (Figure 1) that is associated with cessation of progression of vascular growth toward the retinal periphery. In the subsequent phase of the disease, the ensuing retinal ischemia predisposes to abnormal compensatory neovascularization (9, 10). Of the various factors that have been associated with the development of ROP, low birth weight, low gestational age, supplemental oxygen therapy, and its associated relative hyperoxia dominate.The development of the human retinal vasculature commences at approximately the 16th week of gestation and concludes at term (i.e., the 40th week of gestation) (11). Hence, when an infant is born prematurely, its retinal blood supply is incomplete and highly vulnerable to decay. This immaturity in vascular development predisposes the retina to complications. Major advances have been made over the past 30 years in identifying mechanisms implicated in the genesis of ROP. Comprehension of mechanisms underlying this disorder has, in turn, enhanced understanding of the pathogenesis of ischemic retinal vasculopathies in the adult, for example, diabetic retinopathy (a complication of diabetes mellitus) and neovascular forms of age-related macular degeneration (the major cause of visual impairment in adults over 50 years of age).The oxygen-induced retinopathy (OIR) model of ischemic retinop...

Nitrative stress has an important role in microvascular degeneration leading to ischemia in conditions such as diabetic retinopathy and retinopathy of prematurity. Thus far, mediators of nitrative stress have been poorly characterized. We recently described that trans-arachidonic acids are major products of NO(2)(*)-mediated isomerization of arachidonic acid within the cell membrane, but their biological relevance is unknown. Here we show that trans-arachidonic acids are generated in a model of retinal microangiopathy in vivo in a NO(*)-dependent manner. They induce a selective time- and concentration-dependent apoptosis of microvascular endothelial cells in vitro, and result in retinal microvascular degeneration ex vivo and in vivo. These effects are mediated by an upregulation of the antiangiogenic factor thrombospondin-1, independently of classical arachidonic acid metabolism. Our findings provide new insight into the molecular mechanisms of nitrative stress in microvascular injury and suggest new therapeutic avenues in the management of disorders involving nitrative stress, such as ischemic retinopathies and encephalopathies.

The authors demonstrate for the first time pronounced, sustained choroidal vascular involution during the development of ROP. Findings also suggest that effective therapeutic strategies to counter ROP should consider choroidal preservation.

Septic shock in the neonatal period has a very poor outcome. Data underscore the extreme vulnerability of very low birth weight infants to septic shock, particularly to gram-negative species.

No abstract

Ped3CB-A provides easy-to-use, well-balanced, and safe nutritional support. Nutritional intakes and weight gain were within the recent PN recommendations in preterm infants.

BackgroundAntibiotic resistance is a threat in developing countries (DCs) because of the high burden of bacterial disease and the presence of risk factors for its emergence and spread. This threat is of particular concern for neonates in DCs where over one-third of neonatal deaths may be attributable to severe infections and factors such as malnutrition and HIV infection may increase the risk of death. Additional, undocumented deaths due to severe infection may also occur due to the high frequency of at-home births in DCs.MethodsWe conducted a systematic review of studies published after 2000 on community-acquired invasive bacterial infections and antibiotic resistance among neonates in DCs. Twenty-one articles met all inclusion criteria and were included in the final analysis.ResultsNinety percent of studies recruited participants at large or university hospitals. The majority of studies were conducted in Sub-Saharan Africa (n = 10) and the Indian subcontinent (n = 8). Neonatal infection incidence ranged from 2.9 (95% CI 1.9–4.2) to 24 (95% CI 21.8–25.7) for 1000 live births. The three most common bacterial isolates in neonatal sepsis were Staphylococcus aureus, Escherichia coli, and Klebsiella. Information on antibiotic resistance was sparse and often relied on few isolates. The majority of resistance studies were conducted prior to 2008. No conclusions could be drawn on Enterobacteriaceae resistance to third generation cephalosporins or methicillin resistance among Staphylococcus aureus.ConclusionsAvailable data were found insufficient to draw a true, recent, and accurate picture of antibiotic resistance in DCs among severe bacterial infection in neonates, particularly at the community level. Existing neonatal sepsis treatment guidelines may no longer be appropriate, and these data are needed as the basis for updated guidelines. Reliable microbiological and epidemiological data at the community level are needed in DCs to combat the global challenge of antibiotic resistance especially among neonates among whom the burden is greatest.