Preterm brain injury is a major cause of disability in later life, and may result in motor, cognitive and behavioural impairment for which no treatment is currently available. The aetiology is considered as multifactorial, and one underlying key player is inflammation leading to white and grey matter injury. Extracellular vesicles secreted by mesenchymal stem/stromal cells (MSC-EVs) have shown therapeutic potential in regenerative medicine. Here, we investigated the effects of MSC-EV treatment on brain microstructure and maturation, inflammatory processes and long-time outcome in a rodent model of inflammation-induced brain injury. 3-Day-old Wistar rats (P3) were intraperitoneally injected with 0.25mg/kg lipopolysaccharide or saline and treated with two repetitive doses of 1×108 cell equivalents of MSC-EVs per kg bodyweight. Cellular degeneration and reactive gliosis at P5 and myelination at P11 were evaluated by immunohistochemistry and western blot. Long-term cognitive and motor function was assessed by behavioural testing. Diffusion tensor imaging at P125 evaluated long-term microstructural white matter alterations. MSC-EV treatment significantly ameliorated inflammation-induced neuronal cellular degeneration reduced microgliosis and prevented reactive astrogliosis. Short-term myelination deficits and long-term microstructural abnormalities of the white matter were restored by MSC-EV administration. Morphological effects of MSC-EV treatment resulted in improved long-lasting cognitive functions INTERPRETATION: MSC-EVs ameliorate inflammation-induced cellular damage in a rat model of preterm brain injury. MSC-EVs may serve as a novel therapeutic option by prevention of neuronal cell death, restoration of white matter microstructure, reduction of gliosis and long-term functional improvement.

Cerebral white matter injury is a leading cause of adverse neurodevelopmental outcome in prematurely born infants involving cognitive deficits in later life. Despite increasing knowledge about the pathophysiology of perinatal brain injury, therapeutic options are limited. In the adult demyelinating disease multiple sclerosis the sphingosine-1-phosphate (S1P) receptor modulating substance fingolimod (FTY720) has beneficial effects. Herein, we evaluated the neuroprotective potential of FTY720 in a neonatal model of oxygen-toxicity, which is associated with hypomyelination and impaired neuro-cognitive outcome. A single dose of FTY720 (1mg/kg) at the onset of neonatal hyperoxia (24h 80% oxygen on postnatal day 6) resulted in improvement of neuro-cognitive development persisting into adulthood. This was associated with reduced microstructural white matter abnormalities 4 months after the insult. In search of the underlying mechanisms potential non-classical (i.e. lymphocyte-independent) pathways were analysed shortly after the insult, comprising modulation of oxidative stress and local inflammatory responses as well as myelination, oligodendrocyte degeneration and maturation. Treatment with FTY720 reduced hyperoxia-induced oxidative stress, microglia activation and associated pro-inflammatory cytokine expression. In vivo and in vitro analyses further revealed that oxygen-induced hypomyelination is restored to control levels, which was accompanied by reduced oligodendrocyte degeneration and enhanced maturation. Furthermore, hyperoxia-induced elevation of S1P receptor 1 (S1P1) protein expression on in vitro cultured oligodendrocyte precursor cells was reduced by activated FTY720 and protection from degeneration is abrogated after selective S1P1 blockade. Finally, FTY720s' classical mode of action (i.e. retention of immune cells within peripheral lymphoid organs) was analysed demonstrating that FTY720 diminished circulating lymphocyte counts independent from hyperoxia. Cerebral immune cell counts remained unchanged by hyperoxia and by FTY720 treatment. Taken together, these results suggest that beneficial effects of FTY720 in neonatal oxygen-induced brain injury may be rather attributed to its anti-oxidative and anti-inflammatory capacity acting in concert with a direct protection of developing oligodendrocytes than to a modulation of peripheral lymphocyte trafficking. Thus, FTY720 might be a potential new therapeutic option for the treatment of neonatal brain injury through reduction of white matter damage.

Acute hypothermia treatment (HT) is the only clinically established intervention following neonatal hypoxic-ischemic brain injury. However, almost half of all cooled infants still die or suffer from long-lasting neurological impairments. Regenerative therapies, such as mesenchymal stem cells (MSC) appear promising as adjuvant therapy. In the present study, we hypothesized that HT combined with delayed MSC therapy results in augmented protection, improving long-term neurological outcome. Postnatal day 9 (P9) C57BL/6 mice were exposed to hypoxia-ischemia followed by 4 h HT. Murine bone marrow-derived MSC (1 × 10⁶ cells/animal) were administered intranasally at P12. Cytokine and growth factor levels were assessed by ELISA and Luminex® multiplex assay 24 h following MSC delivery. One week after HI, tissue injury and neuroinflammatory responses were determined by immunohistochemistry and western blot. Long-term motor-cognitive outcome was assessed 5 weeks post injury. MSC responses to the brains' environment were evaluated by gene expression analysis in MSC, co-cultured with brain homogenates isolated at P12. Both, MSC and HT improved motor deficits, while cognitive function could only be restored by MSC. Compared to each single therapy, combined treatment led to increased long-lasting motor-cognitive deficits and exacerbated brain injury, accompanied by enhanced endothelial activation and peripheral immune cell infiltration. MSC co-cultured with brain extracts of HT-treated animals revealed increased pro-inflammatory cytokine and decreased growth factor expression. In vivo protein analysis showed higher pro-inflammatory cytokine levels after combined treatment compared to single therapy. Furthermore, HI-induced increase in growth factors was normalized to control levels by HT and MSC single therapy, while the combination induced a further decline below control levels. Our results suggest that alteration of the brains' microenvironment by acute HT modulates MSC function resulting in a pro-inflammatory environment combined with alteration of the homeostatic growth factor milieu in the neonatal hypoxic-ischemic brain. This study delineates potential unexpected side effects of cell-based therapies as add-on therapy for acute hypothermia treatment.

Aim: To identify maternal, obstetric, and neonatal risk factors related to perinatal arterial ischaemic stroke (PAIS) diagnosed within 28 days after birth and to understand the underlying pathophysiology.Method: For case and control ascertainment, we used active surveillance in 345 paediatric hospitals and a population‐based perinatal database for quality assurance of hospital care. We analysed complete cases of PAIS using logistic regression. Multivariate analysis was guided by a directed acyclic graph.Results: After exclusion of records with missing data, we analysed 134 individuals with PAIS and 576 comparison individuals. In univariate analysis, male sex, preterm birth (<37wks gestational age), small for gestational age (SGA), low umbilical artery pH (<7.1), low 5‐minute‐Apgar score (<7), multiple pregnancies, hypoxia, intubation/mask ventilation, nulliparity, Caesarean section, vaginal‐operative delivery, chorioamnionitis, and oligohydramnios were associated with an increased risk. Mutual adjustment yielded male sex (odds ratio [OR] 1.81; 95% confidence interval [CI] 1.20–2.73), multiple birth (OR 3.22; 95% CI 1.21–8.58), chorioamnionitis (OR 9.89; 95% CI 2.88–33.94), preterm birth (OR 1.86; 95% CI 1.01–3.43), and SGA (OR 3.05; 95% CI 1.76–5.28) as independent risk factors.Interpretation: We confirmed the increased risk in males and the role of chorioamnionitis and SGA for PAIS, pointing to the importance of inflammatory processes and fetal–placental insufficiency. Multiple birth and preterm birth were additional risk factors.What this paper adds: Chorioamnionitis and small for gestational age (SGA) precede perinatal arterial ischaemic stroke (PAIS). Chorioamnionitis and SGA are independent risk factors for PAIS. Inflammatory processes and fetal–placental insufficiency are the likely underlying mechanisms. Multiple birth and preterm birth are additional risk factors.

Approximately 11.1% of all newborns worldwide are born preterm. Improved neonatal intensive care significantly increased survival rates over the last decades but failed to reduce the risk for the development of chronic lung disease (i.e., bronchopulmonary dysplasia (BPD)) and impaired neurodevelopment (i.e., encephalopathy of prematurity (EoP)), two major long‐term sequelae of prematurity. Premature infants are exposed to relative hyperoxia, when compared to physiological in‐utero conditions and, if needed to additional therapeutic oxygen supplementation. Both are associated with an increased risk for impaired organ development. Since the detrimental effects of hyperoxia on the immature retina are known for many years, lung and brain have come into focus in the last decade. Hyperoxia‐induced excessive production of reactive oxygen species leading to oxidative stress and inflammation contribute to pulmonary growth restriction and abnormal neurodevelopment, including myelination deficits. Despite a large body of studies, which unraveled important pathophysiological mechanisms for both organs at risk, the majority focused exclusively either on lung or on brain injury. However, considering that preterm infants suffering from BPD are at higher risk for poor neurodevelopmental outcome, an interaction between both organs seems plausible. This review summarizes recent findings regarding mechanisms of hyperoxia‐induced neonatal lung and brain injury. We will discuss common pathophysiological pathways, which potentially link both injured organ systems. Furthermore, promises and needs of currently suggested therapies, including pharmacological and regenerative cell‐based treatments for BPD and EoP, will be emphasized. Limited therapeutic approaches highlight the urgent need for a better understanding of the mechanisms underlying detrimental effects of hyperoxia on the lung‐brain axis in order to pave the way for the development of novel multimodal therapies, ideally targeting both severe preterm birth‐associated complications.

Recent research found evidence supporting music therapy for preterm infants to stabilize vital signs and possibly promote neurodevelopment. Even though preterm infants spend a considerable amount of time sleeping, the effectiveness of music therapy during sleep has not been studied. The aim of this study was to investigate the effect of music therapy on preterm infants’ vital signs with respect to the state of wakefulness. The first 20 consecutive infants born with <32 weeks’ gestational age (GA) from the intervention group of an ongoing randomized controlled trial received live music therapy twice a week until hospital discharge. The heart rate, respiratory rate, oxygen saturation, and state of wakefulness were recorded before and after therapy. We observed significantly lower heart and respiratory rates and higher oxygen saturation after live music therapy sessions in general (mean differences −4.9 beats per min; −7.0 breaths per min and +1.5%, respectively). When music therapy was applied during sleep, respiratory rates significantly lowered by 8.8 breaths per min and oxygen saturation increased by 1.6%, whereas in the awake state the vital parameters did not significantly change (heart rate −5.2 beats per min; respiratory rate +0.6 breaths per min and oxygen saturation +1.0%). Music therapy stabilized the respiratory rates and oxygen saturations in sleeping preterm infants.