Hanna E. Reinebrant

Stillbirths: recall to action in high-income countries

Variation in stillbirth rates across high-income countries and large equity gaps within high-income countries persist. If all high-income countries achieved stillbirth rates equal to the best performing countries, 19,439 late gestation (28 weeks or more) stillbirths could have been avoided in 2015. The proportion of unexplained stillbirths is high and can be addressed through improvements in data collection, investigation, and classification, and with a better understanding of causal pathways. Substandard care contributes to 20-30% of all stillbirths and the contribution is even higher for late gestation intrapartum stillbirths. National perinatal mortality audit programmes need to be implemented in all high-income countries. The need to reduce stigma and fatalism related to stillbirth and to improve bereavement care are also clear, persisting priorities for action. In high-income countries, a woman living under adverse socioeconomic circumstances has twice the risk of having a stillborn child when compared to her more advantaged counterparts. Programmes at community and country level need to improve health in disadvantaged families to address these inequities.

Minocycline: a neuroprotective agent for hypoxic-ischemic brain injury in the neonate?

Minocycline is a second‐generation tetracycline and a potential neuroprotective intervention following brain injury. However, despite the recognized beneficial effects of minocycline in a multitude of adult disease states, the clinical application of minocycline in neonates is contentious. Tetracyclines, as a class, are not usually administered to neonates, but there is compelling evidence that minocycline reduces brain injury after neonatal hypoxic‐ischemic brain injury. This Review focuses on the evidence for minocycline use in neonates by considering aspects of pharmacology, drug regimens, functional outcomes, and mechanisms of action.

Delayed P2X4R expression after hypoxia-ischemia is associated with microglia in the immature rat brain.

In a preterm hypoxia-ischemia model in the post-natal day 3 rat, we characterized how the expression of purine ionotropic P2X(4) receptors change in the brain post-insult. After hypoxia-ischemia, P2X(4) receptor expression increased significantly and was associated with a late increase in ionised calcium binding adapter molecule-1 protein expression indicative of microglia cell activation. Minocycline, a potent inhibitor of microglia, attenuated the hypoxia-ischemia-induced increase in P2X(4) receptor expression. We postulate that P2X(4) receptor-positive microglia may represent a population of secondary injury-induced activated microglia. Future studies will determine whether this population contributes to the progression of injury in the immature brain.

Efficacy of post-insult minocycline administration to alter long-term hypoxia-ischemia-induced damage to the serotonergic system in the immature rat brain

Neuroinflammation is a key mechanism contributing to long-term neuropathology observed after neonatal hypoxia-ischemia (HI). Minocycline, a second-generation tetracycline, is a potent inhibitor of neuroinflammatory mediators and is successful for at least short-term amelioration of neuronal injury after neonatal HI. However the long-term efficacy of minocycline to prevent injury to a specific neuronal network, such as the serotonergic (5-hydroxytryptamine, 5-HT) system, is not known. In a post-natal day 3 (P3) rat model of preterm HI we found significant reductions in 5-HT levels, 5-HT transporter expression and numbers of 5-HT-positive dorsal raphé neurons 6 weeks after insult compared to control animals. Numbers of activated microglia were significantly elevated in the thalamus and dorsal raphé although the greatest numbers were observed in the thalamus. Brain levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were also significantly elevated on P45 in the thalamus and frontal cortex. Post-insult administration of minocycline for 1 week (P3-P9) attenuated the P3 HI-induced increases in numbers of activated microglia and levels of TNF-α and IL-1β on P45 with concurrent changes in serotonergic outcomes. The parallel prevention of P3 HI-induced serotonergic changes suggests that inhibition of neuroinflammation within the first week after P3 HI injury was sufficient to prevent long-term neuroinflammation as well as serotonergic system damage still evident at 6 weeks. Thus early, post-insult administration of minocycline may target secondary neuroinflammation and represent a long-term therapy to preserve the integrity of the central serotonergic network in the preterm neonate.

Ibuprofen inhibits neuroinflammation and attenuates white matter damage following hypoxia–ischemia in the immature rodent brain

Damage to major white matter tracts is a hallmark mark feature of hypoxic-ischemic (HI) brain injury in the preterm neonate. There is, however, no therapeutic intervention to treat this injury. Neuroinflammation is thought to play a prominent role in the pathogenesis of the HI-induced white matter damage but identification of the key mediators that constitute the inflammatory response remain to be fully elucidated. Cyclooxygenase enzymes (COX-1 and COX-2) are candidate neuroinflammatory mediators that may contribute to the HI-induced demise of early oligodendrocyte progenitors and myelination. We investigated whether ibuprofen, a non-steroidal anti-inflammatory drug that inhibits COX enzymes, can attenuate neuroinflammation and associated white matter damage incurred in a rodent model of preterm HI. On postnatal day 3 (P3), HI was produced (right carotid artery ligation and 30 min 6% O(2)). An initial dose of ibuprofen (100mg/kg, s.c.) was administered 2h after HI followed by a maintenance dose (50mg/kg, s.c.) every 24h for 6 days. Post-HI ibuprofen treatment significantly attenuated the P3 HI-induced increases in COX-2 protein expression as well as interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) levels in the brain. Ibuprofen treatment also prevented the HI-induced loss O4- and O1-positive oligodendrocyte progenitor cells and myelin basic protein (MBP)-positive myelin content one week after P3 HI. These findings suggest that a repeated, daily, ibuprofen treatment regimen administered after an HI insult may be a potential therapeutic intervention to prevent HI-induced damage to white matter progenitors and early myelination in the preterm neonate.

Inhibition of neuroinflammation prevents injury to the serotonergic network after hypoxia-ischemia in the immature rat brain

The phenotypic identities and characterization of neural networks disrupted after neonatal hypoxia-ischemia (HI) in the preterm brain remain to be elucidated. Interruption of the central serotonergic (5-hydroxytryptamine [5-HT]) system can lead to numerous functional deficits, many of which match those in human preterm neonates exposedto HI. How the central serotonergic network is damaged after HIand mechanisms underlying such injury are not known. We used aPostnatal Day 3 rat model of preterm HI and found parallel reductionsin the 5-HT transporter expression, 5-HT levels and numbers of 5-HT-positive dorsal raphe neurons 1 week after insult. Post-HI administration of minocycline, an inhibitor of activated microglia, attenuated HI-induced damage to the serotonergic network. Minocycline effects seemed to be region specific, that is, where there was microglialactivation and increases in tumor necrosis factor-&agr; and interleukin1&bgr;. The concurrent improvement in serotonergic outcomes suggests that inhibition of neuroinflammation prevented damage to theserotonergic neurons rather than affected the regulation of 5-HT orserotonin transporter. These data elucidate the mechanisms of serotonergic network injury in HI, and despite the known adverse effects associated with the use of minocycline in neonates, postinsult administration of minocycline may represent a novel approach to counter neuroinflammation and preserve the integrity of the central serotonergic network in the preterm neonate.

Long-term losses of amygdala corticotropin-releasing factor neurons are associated with behavioural outcomes following neonatal hypoxia-ischemia

Neuronal losses are observed in the brain after neonatal hypoxia-ischemia (HI) however few studies have examined the effects of HI on specific neuronal phenotypes and their possible contribution to behavioural outcomes. In the present study we examined whether postnatal day 3 (P3) HI alters numbers of corticotropin-releasing factor (CRF) and neuropeptide-Y (NPY) neurons in the paraventricular nucleus of the hypothalamus (PVN), the bed nucleus of the stria terminalis (BNST) and the amygdala, 1 (P10) and 6 (P45) weeks after P3 HI. A significant reduction in the number of CRF-positive neurons in the PVN, central nucleus of the amygdala (CeA) and BNST ipsilateral to the carotid ligation 1 and 6 weeks after P3 HI was observed. There was also a significant reduction in the number of NPY-positive neurons in the PVN, amygdala and BNST ipsilateral to the carotid ligation 1 week after P3 HI. However after 6 weeks, only the number of PVN NPY-positive neurons decreased significantly. At 6 weeks post-insult, the number of CeA CRF-positive neurons was inversely associated with locomotor activity and exploratory behaviour in an open field. In contrast, no significant correlations between neuronal counts and early neurodevelopment tests performed on P10 were observed. Thus after P3 HI persistent losses of CRF- and NPY-positive neurons occur and the loss of CeA CRF neurons may provide a central anatomical mechanism underlying neurobehavioural deficits observed 6 weeks after P3 HI.

Differential effects of neonatal hypoxic-ischemic brain injury on brainstem serotonergic raphe nuclei.

Serotonergic fibres have a pervasive innervation of hypoxic-ischemic (HI)-affected areas in the neonatal brain and serotonin (5-HT) is pivotal in numerous neurobehaviours that match many HI-induced deficits. However, little is known about how neonatal HI affects the serotonergic system. We therefore examined whether neonatal HI can alter numbers of serotonergic raphe neurons in specific sub-divisions of the midbrain and brainstem since these nuclei are the primary sources of serotonin throughout the central nervous system (CNS). We utilised an established neonatal HI model in the postnatal day 3 (P3) rat pup (right common carotid artery ligation+30min 6% O2) and determined the effects of P3 HI on 5-HT counts in 5 raphe sub-divisions in the midbrain and brainstem one and six weeks later. After P3 HI, numbers of 5-HT-positive neurons were significantly decreased in the dorsal raphe dorsal, dorsal raphe ventrolateral and dorsal raphe caudal nuclei on P10 but only in the dorsal raphe dorsal and dorsal raphe ventrolateral nuclei on P45. In contrast, P3 HI did not alter counts in the dorsal raphe interfascicular and raphe magnus nuclei. We also discovered that P3 HI significantly reduces brainstem SERT protein expression; the key regulator of 5-HT in the CNS. In conclusion, neonatal HI injury caused significant disruption of the brainstem serotonergic system that can persist for up to six weeks after the insult. The different vulnerabilities of serotonergic populations in specific raphe nuclei suggest that certain raphe nuclei may underpin neurological deficits in HI-affected neonates through to adulthood.

Seeking order amidst chaos: A systematic review of classification systems for causes of stillbirth and neonatal death, 2009-2014

BackgroundEach year, about 5.3 million babies die in the perinatal period. Understanding of causes of death is critical for prevention, yet there is no globally acceptable classification system. Instead, many disparate systems have been developed and used. We aimed to identify all systems used or created between 2009 and 2014, with their key features, including extent of alignment with the International Classification of Diseases (ICD) and variation in features by region, to inform the World Health Organization’s development of a new global approach to classifying perinatal deaths.MethodsA systematic literature review (CINAHL, EMBASE, Medline, Global Health, and PubMed) identified published and unpublished studies and national reports describing new classification systems or modifications of existing systems for causes of perinatal death, or that used or tested such systems, between 2009 and 2014. Studies reporting ICD use only were excluded. Data were independently double-extracted (except from non-English publications). Subgroup analyses explored variation by extent and region.ResultsEighty-one systems were identified as new, modifications of existing systems, or having been used between 2009 and 2014, with an average of ten systems created/modified each year. Systems had widely varying characteristics: (i) comprehensiveness (40 systems classified both stillbirths and neonatal deaths); (ii) extent of use (systems were created in 28 countries and used in 40; 17 were created for national use; 27 were widely used); (iii) accessibility (three systems available in e-format); (iv) underlying cause of death (64 systems required a single cause of death); (v) reliability (10 systems tested for reliability, with overall Kappa scores ranging from .35–.93); and (vi) ICD alignment (17 systems used ICD codes). Regional databases were not searched, so system numbers may be underestimated. Some non-differential misclassification of systems was possible.ConclusionsThe plethora of systems in use, and continuing system development, hamper international efforts to improve understanding of causes of death. Recognition of the features of currently used systems, combined with a better understanding of the drivers of continued system creation, may help the development of a truly effective global system.

Characteristics of a global classification system for perinatal deaths: a Delphi consensus study

BackgroundDespite the global burden of perinatal deaths, there is currently no single, globally-acceptable classification system for perinatal deaths. Instead, multiple, disparate systems are in use world-wide. This inconsistency hinders accurate estimates of causes of death and impedes effective prevention strategies. The World Health Organisation (WHO) is developing a globally-acceptable classification approach for perinatal deaths. To inform this work, we sought to establish a consensus on the important characteristics of such a system.MethodsA group of international experts in the classification of perinatal deaths were identified and invited to join an expert panel to develop a list of important characteristics of a quality global classification system for perinatal death. A Delphi consensus methodology was used to reach agreement. Three rounds of consultation were undertaken using a purpose built on-line survey. Round one sought suggested characteristics for subsequent scoring and selection in rounds two and three.ResultsThe panel of experts agreed on a total of 17 important characteristics for a globally-acceptable perinatal death classification system. Of these, 10 relate to the structural design of the system and 7 relate to the functional aspects and use of the system.ConclusionThis study serves as formative work towards the development of a globally-acceptable approach for the classification of the causes of perinatal deaths. The list of functional and structural characteristics identified should be taken into consideration when designing and developing such a system.