Mitochondrial control of hypoxia-induced pathological retinal angiogenesis.

OBJECTIVE: Pathological retinal neovascularization is vision-threatening. In mouse oxygen-induced retinopathy (OIR) we sought to define mitochondrial respiration changes longitudinally during hyperoxia-induced vessel loss and hypoxia-induced neovascularization, and to test interventions addressing those changes to prevent neovascularization. METHODS: OIR was induced in C57BL/6J mice and retinal vasculature was examined at maximum neovessel formation. We assessed total proteome changes and the ratio of mitochondrial to nuclear DNA copy numbers (mtDNA/nDNA) of OIR vs. control retinas, and mitochondrial oxygen consumption rates (OCR) in ex vivo OIR vs. control retinas (BaroFuse). Pyruvate vs. vehicle control was supplemented to OIR mice either prior to or during neovessel formation. RESULTS: In OIR vs. control retinas, global proteomics showed decreased retinal mitochondrial respiration at peak neovascularization. OCR and mtDNA/nDNA were also decreased at peak neovascularization suggesting impaired mitochondrial respiration. In vivo pyruvate administration during but not prior to neovessel formation (in line with mitochondrial activity time course) suppressed NV. CONCLUSIONS: Mitochondrial energetics were suppressed during retinal NV in OIR. Appropriately timed supplementation of pyruvate may be a novel approach in neovascular retinal diseases.

Timed topical dexamethasone eye drops improve mitochondrial function to prevent severe retinopathy of prematurity.

Pathological neovascularization in retinopathy of prematurity (ROP) can cause visual impairment in preterm infants. Current ROP treatments which are not preventative and only address late neovascular ROP, are costly and can lead to severe complications. We showed that topical 0.1% dexamethasone eye drops administered prior to peak neovessel formation prevented neovascularization in five extremely preterm infants at high risk for ROP and suppressed neovascularization by 30% in mouse oxygen-induced retinopathy (OIR) modeling ROP. In contrast, in OIR, topical dexamethasone treatment before any neovessel formation had limited efficacy in preventing later neovascularization, while treatment after peak neovessel formation had a non-statistically significant trend to exacerbating disease. Optimally timed topical dexamethasone suppression of neovascularization in OIR was associated with increased retinal mitochondrial gene expression and decreased inflammatory marker expression, predominantly found in immune cells. Blocking mitochondrial ATP synthetase reversed the inhibitory effect of dexamethasone on neovascularization in OIR. This study provides new insights into topical steroid effects in retinal neovascularization and into mitochondrial function in phase II ROP, and suggests a simple clinical approach to prevent severe ROP.

Nutritional interventions to prevent retinopathy of prematurity.

Very preterm infants are at high risk of growth failure. Poor weight gain is a prominent risk factor for retinopathy of prematurity (ROP) and optimizing nutrition could potentially promote growth and reduce ROP. Most infants at risk of ROP need parenteral nutrition initially and studies of enhanced parenteral provision of lipids and amino acids have suggested a beneficial effect on ROP. Higher amino acid intake was associated with lower incidence of hyperglycemia, a risk factor for ROP. For very preterm infants, providing unpasteurized fortified raw maternal breast milk appears to have a dose-dependent preventive effect on ROP. These infants become deficient in arachidonic acid (ArA) and docosahexaenoic acid (DHA) after birth when the maternal supply is lost. Earlier studies have investigated the impact of omega-3 fatty acids on ROP with mixed results. In a recent study, early enteral supplementation of ArA 100 mg/kg/d and DHA 50 mg/kg/d until term equivalent age reduced the incidence of severe ROP by 50%. IMPACT: Previous reviews of nutritional interventions to prevent morbidities in preterm infants have mainly addressed bronchopulmonary dysplasia, brain lesions and neurodevelopmental outcome. This review focusses on ROP. Neonatal enteral supplementation with arachidonic acid and docosahexaenoic acid, at levels similar to the fetal accretion rate, has been found to reduce severe ROP by 50% in randomized controlled trials.

Neurofilament light chain associates with IVH and ROP in extremely preterm infants.

BACKGROUND: Neurofilament light chain (NfL) is known for indicating adult brain injury, but the role of NfL in extremely preterm infants is less studied. This study examines the relationship between NfL and neurovascular morbidities in these infants. METHODS: A secondary analysis of the Mega Donna Mega trial was conducted on preterm infants <28 weeks gestational age (GA). The study measured NfL levels and proteomic profiles related to the blood-brain barrier in serum from birth to term-equivalent age, investigating the association of NfL with GA, retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), and blood-brain barrier proteins. RESULTS: Higher NfL levels were seen in the first month in infants with severe IVH and for those born <25 weeks GA (independent of ROP or IVH). Additionally, infants born at 25-27 weeks GA with high NfL were at increased risk of developing severe ROP (independent of IVH). NfL was significantly associated with the proteins CDH5, ITGB1, and JAM-A during the first month. CONCLUSION: NfL surges after birth in extremely preterm infants, particularly in those with severe IVH and ROP, and in the most immature infants regardless of IVH or ROP severity. These findings suggest NfL as a potential predictor of neonatal morbidities, warranting further validation studies. IMPACT STATEMENT: This study shows that higher NfL levels are related to neurovascular morbidities in extremely preterm infants. The degree of immaturity seems important as infants born <25 weeks gestational age exhibited high postnatal serum NfL levels irrespective of neurovascular morbidities. Our findings suggest a potential link between NfL and neurovascular morbidities possibly affected by a more permeable blood-brain barrier.

Bacterial species in cord blood and their significance in the context of clinical use.

Approximately 90 % of infants born before 28 full weeks(extremely-preterm-infants) receive erythrocyte transfusions in early life. Umbilical cord blood(UCB) has been investigated as an alternative source for erythrocyte transfusions to preterm neonates. This retrospective study aimed to compile/evaluate spectrum of bacteria groups/species intermittently detected in processed UCB at National-Swedish-Cord blood bank, (NS-CBB) during the years 2008-2020. Consecutive data from the years 2008-2020 were investigated. UCB from healthy newborns born after 37 full weeks of gestation was collected following clamping of cord (1 min) through cannulation of umbilical vein(vaginal-and C-section-deliveries). In total, 5194 cord blood units (UCBUs) that met NS-CBB-guidelines for total nucleated-cell-content(TNC) were manufactured from 8875 collections. Of 5194 UCBUs,77,6 % were from vaginal-and 22,4 % from C-section deliveries.Samples(10 mL) were collected from surplus eryhtrocyte fraction post-processing(n = 5194), transferred into BACT/ALERT® aerobic/anaerobic culture flasks and monitored 10 days using BACT/ALERT®-3D-Microbial-Detection-Systems. Positive samples were subcultured and typed for bacterial groups and/or species. Out of 5194 processed sampled UCB units,186 (3,6 %) were discarded due to positive sterility tests, 92 % were detected in samples from vaginal-deliveries and 8 % from C-section-deliveries. In all,16 different groups of bacteria and 27 species were identified. Common bacterial/groups and species were anaerobe gram-negative rods(n = 28),coagulase-negative-staphylococci(n = 21),gram-positive rods(n = 21),anaerobe-gram-positive cocci(n = 20) and viridans-streptococci(n = 13). Extracted from these results,in positive samples(n = 13) from C-section deliveries, bacteria were found:viridans-streptococci(n = 7),Aerococcus-urinae(n = 1), Staphylococcus lugdunensis(n = 1),other coagulase-negative staphylococci(n = 1) or a mix of aerobic/anaerobic bacteria(n = 3). Our results are in alignment with previously published contamination rates in processed UCBUs. Still, results point towards importance of strict microbial monitoring when manufacturing UCBUs to achieve patient-safe- products for stem-cell transplantation/transfusion.

Challenges of parenting children born before 24 weeks of gestation.

AIM: To assess experience of care, well-being of parents and children's development in a cohort of extremely premature infants born <24 weeks of gestation in Sweden from 2007 to 2018. METHODS: A survey based on multiple questionnaires answered by 124/349 (35.5%) parents. RESULTS: The median age of parents and children was 43 and 9 years, respectively; 74.2% were mothers. Parents expressed high healthcare satisfaction. Following discharge from neonatal care, the satisfaction with the infant's treatment, support from personnel and being respected as a parent significantly declined but remained high. The criteria for suspected developmental deviation according to the screening test early symptomatic syndromes eliciting neurodevelopmental clinical examinations-questionnaire was fulfilled by 84.3%, 55.6% had suspected avoidant restrictive food intake disorder and 47.9% had visual perception problems. Parents experienced severe fatigue (48.6%) despite strong social support and family self-efficacy. Economic support was provided to 30.6%, and 37.9% of children were enrolled in habilitation services. CONCLUSION: This study highlighted the substantial challenges faced by parents of infants born before 24 weeks of gestation, including decreased satisfaction post-discharge, fatigue and concerns about children's well-being. The findings underscore the need for comprehensive family-centred support and long-term multi-professional follow-up centres.

Therapeutic Effects of Anti-Inflammatory and Anti-Oxidant Nutritional Supplementation in Retinal Ischemic Diseases.

Appropriate nutrients are essential for cellular function. Dietary components can alter the risk of systemic metabolic diseases, including cardiovascular diseases, cancer, diabetes, and obesity, and can also affect retinal diseases, including age-related macular degeneration, diabetic retinopathy, and glaucoma. Dietary nutrients have been assessed for the prevention or treatment of retinal ischemic diseases and the diseases of aging. In this article, we review clinical and experimental evidence concerning the potential of some nutritional supplements to prevent or treat retinal ischemic diseases and provide further insights into the therapeutic effects of nutritional supplementation on retinopathies. We will review the roles of nutrients in preventing or protecting against retinal ischemic diseases.

FGF21 via mitochondrial lipid oxidation promotes physiological vascularization in a mouse model of Phase I ROP.

Hyperglycemia in early postnatal life of preterm infants with incompletely vascularized retinas is associated with increased risk of potentially blinding neovascular retinopathy of prematurity (ROP). Neovascular ROP (Phase II ROP) is a compensatory but ultimately pathological response to the suppression of physiological postnatal retinal vascular development (Phase I ROP). Hyperglycemia in neonatal mice which suppresses physiological retinal vascular growth is associated with decreased expression of systemic and retinal fibroblast growth factor 21 (FGF21). FGF21 administration promoted and FGF21 deficiency suppressed the physiological retinal vessel growth. FGF21 increased serum adiponectin (APN) levels and loss of APN abolished FGF21 promotion of physiological retinal vascular development. Blocking mitochondrial fatty acid oxidation also abolished FGF21 protection against delayed physiological retinal vessel growth. Clinically, preterm infants developing severe neovascular ROP (versus non-severe ROP) had a lower total lipid intake with more parenteral and less enteral during the first 4 weeks of life. Our data suggest that increasing FGF21 levels in the presence of adequate enteral lipids may help prevent Phase I retinopathy (and therefore prevent neovascular disease).

Immunostimulatory gene therapy targeting CD40, 4-1BB and IL-2R activates DCs and stimulates antigen-specific T-cell and NK-cell responses in melanoma models.

BACKGROUND: The activation of dendritic cells (DCs) is pivotal for generating antigen-specific T-cell responses to eradicate tumor cells. Hence, immunotherapies targeting this interplay are especially intriguing. Moreover, it is of interest to modulate the tumor microenvironment (TME), as this harsh milieu often impairs adaptive immune responses. Oncolytic viral therapy presents an opportunity to overcome the immunosuppression in tumors by destroying tumor cells and thereby releasing antigens and immunostimulatory factors. These effects can be further amplified by the introduction of transgenes expressed by the virus. METHODS: Lokon oncolytic adenoviruses (LOAd) belong to a platform of chimeric serotype Ad5/35 viruses that have their replication restricted to tumor cells, but the expression of transgenes is permitted in all infected cells. LOAd732 is a novel oncolytic adenovirus that expresses three essential immunostimulatory transgenes: trimerized membrane-bound CD40L, 4-1BBL and IL-2. Transgene expression was determined with flow cytometry and ELISA and the oncolytic function was evaluated with viability assays and xenograft models. The activation profiles of DCs were investigated in co-cultures with tumor cells or in an autologous antigen-specific T cell model by flow cytometry and multiplex proteomic analysis. Statistical differences were analyzed with Kruskal-Wallis test followed by Dunn's multiple comparison test. RESULTS: All three transgenes were expressed in infected melanoma cells and DCs and transgene expression did not impair the oncolytic activity in tumor cells. DCs were matured post LOAd732 infection and expressed a multitude of co-stimulatory molecules and pro-inflammatory cytokines crucial for T-cell responses. Furthermore, these DCs were capable of expanding and stimulating antigen-specific T cells in addition to natural killer (NK) cells. Strikingly, the addition of immunosuppressive cytokines TGF-ß1 and IL-10 did not affect the ability of LOAd732-matured DCs to expand antigen-specific T cells and these cells retained an enhanced activation profile. CONCLUSIONS: LOAd732 is a novel immunostimulatory gene therapy based on an oncolytic adenovirus that expresses three transgenes, which are essential for mediating an anti-tumor immune response by activating DCs and stimulating T and NK cells even under imunosuppressive conditions commonly present in the TME. These qualities make LOAd732 an appealing new immunotherapy approach.

Postnatal serum IGF-1 levels associate with brain volumes at term in extremely preterm infants.

BACKGROUND: Growth factors important for normal brain development are low in preterm infants. This study investigated the link between growth factors and preterm brain volumes at term. MATERIAL/METHODS: Infants born <28 weeks gestational age (GA) were included. Endogenous levels of insulin-like growth factor (IGF)-1, brain-derived growth factor, vascular endothelial growth factor, and platelet-derived growth factor (expressed as area under the curve [AUC] for serum samples from postnatal days 1, 7, 14, and 28) were utilized in a multivariable linear regression model. Brain volumes were determined by magnetic resonance imaging (MRI) at term equivalent age. RESULTS: In total, 49 infants (median [range] GA 25.4 [22.9-27.9] weeks) were included following MRI segmentation quality assessment and AUC calculation. IGF-1 levels were independently positively associated with the total brain (p < 0.001, ß = 0.90), white matter (p = 0.007, ß = 0.33), cortical gray matter (p = 0.002, ß = 0.43), deep gray matter (p = 0.008, ß = 0.05), and cerebellar (p = 0.006, ß = 0.08) volume adjusted for GA at birth and postmenstrual age at MRI. No associations were seen for other growth factors. CONCLUSIONS: Endogenous exposure to IGF-1 during the first 4 weeks of life was associated with total and regional brain volumes at term. Optimizing levels of IGF-1 might improve brain growth in extremely preterm infants. IMPACT: High serum levels of insulin-like growth factor (IGF)-1 during the first month of life were independently associated with increased total brain volume, white matter, gray matter, and cerebellar volume at term equivalent age in extremely preterm infants. IGF-1 is a critical regulator of neurodevelopment and postnatal levels are low in preterm infants. The effects of IGF-1 levels on brain development in extremely preterm infants are not fully understood. Optimizing levels of IGF-1 may benefit early brain growth in extremely preterm infants. The effects of systemically administered IGF-1/IGFBP3 in extremely preterm infants are now being investigated in a randomized controlled trial (Clinicaltrials.gov: NCT03253263).