Impact of hyperthermia on inflammation-related perinatal brain injury

Acetaminophen and Ibuprofen in Pediatric Central Nervous System Malaria: A Randomized Clinical Trial

Importance

A third of children who survive malaria with neurological involvement (central nervous system [CNS] malaria) develop sequelae. A higher maximum temperature (Tmax) and seizures are risk factors for sequelae.

Objective

To compare aggressive antipyretic therapy using scheduled acetaminophen and ibuprofen vs usual care with acetaminophen alone given only for a temperature of 38.5 °C or higher.

Design, Setting, and Participants

This randomized clinical trial was conducted at inpatient pediatric services of 1 tertiary care and 1 district hospital in Zambia and a tertiary care center in Malawi. Included were children aged 2 to 11 years with CNS malaria (excluding those with creatinine >1.2 mg/dL), who were enrolled from 2019 to 2022. Data analysis took place from December 2022 to April 2023.

Intervention

The aggressive antipyretic group received acetaminophen (30 mg/kg load, then 15 mg/kg) plus ibuprofen, 10 mg/kg, every 6 hours, regardless of clinical temperature for 72 hours. The usual care group received 15 mg/kg of acetaminophen as needed every 6 hours for a temperature of 38.5 °C or higher.

Main Outcomes and Measures

The primary outcome variable was Tmax over 72 hours, the total duration of follow-up. Secondary outcomes included seizures and parasite clearance.

Results

Five hundred fifty-three patients were screened, 226 (40.9%) were ineligible, and 57 (10.3%) declined. A total 256 participants (n = 128/group) had a mean (SD) age of 4.3 (2.1) years; 115 (45%) were female, and 141 (55%) were male. The aggressive antipyretic group had a lower Tmax, 38.6 vs 39.2 °C (difference, -0.62 °C; 95% CI, -0.82 to -0.42; P < .001) and lower odds of experiencing multiple or prolonged seizures, 10 (8%) vs 34 children (27%) in the usual care group (odds ratio [OR], 0.26; 95% CI, 0.12 to 0.56). No group difference in parasite clearance time was detected. Severe adverse events occurred in 40 children (15%), 25 (20%) in the usual care group and 15 (12%) in the aggressive antipyretic group, including 13 deaths (10 [8%] and 3 [2%], respectively). Increased creatinine resulted in study drug discontinuation in 8 children (6%) in the usual care group and 13 children (10%) in the aggressive antipyretic group (OR, 1.74; 95% CI, 0.63 to 5.07).

Conclusions and Relevance

This study found that aggressive antipyretic therapy reduced mean Tmax to temperature levels comparable with the Tmax among children without neurological impairments in prior observational studies and improved acute seizure outcomes with no prolongation of parasitemia.

Trial Registration

ClinicalTrials.gov Identifier: NCT03399318.

Increasing Role of Maternal Immune Activation in Neurodevelopmental Disorders

The earliest stages of development are critically sensitive to environmental insults. An unfortunately timed stress on the developing brain can have dramatic consequences for the neurodevelopment and future mental health of the individual. In particular, infection of the mother during pregnancy has been correlated with increased risk of psychiatric and neurodevelopmental disorders. Evidence suggests that maternal immune activation, independently from the infection itself, can be responsible for the outcome in the offspring. This recognition has resulted in expanding study designs from epidemiologic correlations to the search for a causal relationship between activation of the maternal immune system and cognitive consequences for the offspring. However, this causality analysis remained limited in humans until recent work that longitudinally linked specific markers of maternal inflammation during pregnancy with alterations of the newborn brain and cognitive development of toddlers. This focused narrative review compares and discusses the results of these recent studies and places them into the broader landscape of maternal immune activation literature. New data point, in particular, to the association between the levels of interleukin 6 (IL-6) and modifications of the offspring's salience network and subsequent cognitive impairments. This article further emphasizes the need to carefully control for potential confounders in studying the effects of maternal immune activation on the neonatal brain as well as the under-investigated consequences of intra-partum fever on offspring neurodevelopment.

Brain Barrier Disruption and Region-Specific Neuronal Degeneration during Necrotizing Enterocolitis in Preterm Pigs

Necrotizing enterocolitis (NEC) increases the risk of brain injury and impaired neurodevelopment. Rapid brain maturation prior to birth may explain why preterm brains are particularly vulnerable to serious infections. Using pigs as models, we hypothesized that preterm birth was associated with altered blood-cerebrospinal fluid (CSF) barrier (BCSFB) function and cerebral structural deficits, and that NEC was associated with systemic inflammation, BCSFB disruption, and neuroinflammation. First, cesarean-delivered preterm and term pigs (n = 43–44) were euthanized at birth to investigate BCSFB function and markers of brain structural maturation, or on day 5 to measure markers of blood-brain barrier maturation in the hippocampus and striatum (experiment 1). Next, preterm pigs (n = 162) were fed increasing volumes of infant formula to assess NEC lesions, systemic inflammation, BCSFB permeability, cerebral histopathology, hippocampal micro­glial density, and cytokine levels on day 5 (experiments 2 and 3). In experiment 1, preterm newborns had increased CSF-plasma ratios of albumin and raffinose, reduced CSF glucose levels, as well as increased cerebral hydration and reduced white matter myelination compared with term animals. We observed lower hippocampal (but not striatal) perivascular astrocyte coverage for the first 5 days after preterm birth, accompanied by altered cell junction protein levels. In experiments 2 and– 3, piglets with severe NEC lesions showed reduced blood thrombocytes and increased plasma C-reactive protein and interleukin-6 levels. NEC was associated with increased CSF-plasma albumin and raffinose ratios, reduced CSF leukocyte numbers, and increased cerebral hydration. In the hippocampus, NEC was associated with pyramidal neuron loss and increased interleukin-6 levels. In the short term, NEC did not affect cerebral myelination or microglia density. In conclusion, altered BCSFB properties and brain structural deficits were observed in pigs after preterm birth. Acute gastrointestinal NEC lesions were associated with systemic inflammation, increased BCSFB permeability and region-specific neuronal damage. The results demonstrate the importance of early interventions against NEC to prevent brain injury in preterm infants.

A Critical Review of Models of Perinatal Infection

One of the central, unanswered questions in perinatology is why preterm infants continue to have such poor long-term neurodevelopmental, cognitive and learning outcomes, even though severe brain injury is now rare. There is now strong clinical evidence that one factor underlying disability may be infection, as well as nonspecific inflammation, during fetal and early postnatal life. In this review, we examine the experimental evidence linking both acute and chronic infection/inflammation with perinatal brain injury and consider key experimental determinants, including the microglia response, relative brain and immune maturity and the pattern of exposure to infection. We highlight the importance of the origin and derivation of the bacterial cell wall component lipopolysaccharide. Such experimental paradigms are essential to determine the precise time course of the inflammatory reaction and to design targeted neuroprotective strategies to protect the perinatal brain from infection and inflammation.

The importance of temperature on the neurovascular unit

Therapeutic hypothermia is the only treatment that has been shown to be of benefit to infant's ≥ 36 weeks of gestation with hypoxic-ischemic encephalopathy. The evidence for the benefit is based on multiple, well-designed randomized clinical trials. Based on this data, the use of therapeutic hypothermia has been widely disseminated throughout the neonatal community. An important concept in hypoxic-ischemic brain injury is the functioning of the neurovascular unit which links neurons, non-neuronal cellular elements and the capillary endothelial cells to promote optimal barrier maintenance between the brain and systemic circulation, regulation of blood flow and neuro-immunologic functioning. Hypoxic-ischemic injury can trigger increased permeability of the blood-brain-barrier via molecular events within the neurovascular unit and initiate pathways to brain injury. In addition, exposure of the brain to cellular elements from the systemic circulation can further propagate the neuro-inflammatory response. The influence of temperature on injury to the neurovascular unit has received relatively little attention. This review will focus on one component of the neurovascular unit, the blood-brain barrier and its constituents. Specifically, this review will address the effects of hypoxia-ischemia and temperature on the neurovascular unit and potential knowledge gaps which may serve as areas for further investigation.