Human pandemic H1N1 2009 influenza virus causes significant morbidity and mortality with severe acute lung injury due to the excessive inflammatory reaction, even with neuraminidase inhibitor use. The anti‐inflammatory effect of anti‐high‐mobility group box‐1 (HMGB1) monoclonal antibody (mAb) against influenza pneumonia has been reported. In this study, we evaluated the combined effect of anti‐HMGB1 mAb and peramivir against pneumonia induced by influenza A (H1N1) virus in mice. Nine‐week‐old male C57BL/6 mice were inoculated with H1N1 and treated with intramuscularly administered peramivir at 2 and 3 days post‐infection (dpi). The anti‐HMGB1 mAb or a control mAb was administered at 2, 3, and 4 dpi. Survival rates were assessed, and lung lavage and pathological analyses were conducted at 5 and 7 dpi. The combination of peramivir with the anti‐HMGB1 mAb significantly improved survival rate whereas the anti‐HMGB1 mAb alone did not affect virus proliferation in the lungs. This combination therapy also significantly ameliorated histopathological changes, neutrophil infiltration, and macrophage aggregation by inhibiting HMGB1, inflammatory cytokines, and oxidative stress. Fluorescence immunostaining showed that the anti‐HMGB1 mAb inhibited HMGB1 translocation from type I alveolar epithelial cells. In summary, combining anti‐HMGB1 with conventional anti‐influenza therapy might be useful against severe influenza virus infection.

Background No relationship has been reported between nonopiate neonatal abstinence syndrome (NAS) and anthropometric indices, including head circumference (HC). The purpose of this study was to determine the relationship between maternal nonopioid drug use and HC at birth in neonates with NAS. Methods This retrospective observational study included neonates born between January 1, 2010 and March 31, 2019, whose mothers had been taking antipsychotic, antidepressant, sedative, or anticonvulsant medications. The outcome measures were HCs of NAS infants and controls. Results Of 159 infants, 33 (21%) were diagnosed with NAS. There was no maternal opioid use among mothers during pregnancy. The HCs in the NAS group were significantly smaller than those in the control group. The median z-scores for HC at birth were −0.20 and 0.29 in the NAS group and the control group, respectively (P = .011). The median HCs at birth were 33.0 and 33.5 cm in the NAS group and the control group, respectively. Multivariate analysis revealed that maternal antipsychotic drug use and selective serotonin reuptake inhibitors were independently associated with NAS (P < .001 and P = .004, respectively). Notably, benzodiazepine use and smoking were not independent risk factors. Conclusions The results suggest an association between maternal antipsychotic drug use and NAS, which was further associated with decreased HC. Careful monitoring of maternal drug use should be considered to improve fetal outcomes.

The high‐mobility group box‐1 (HMGB1) protein is a transcription‐regulating protein located in the nucleus. However, it serves as a damage‐associated molecular pattern protein that activates immune cells and stimulates inflammatory cytokines to accentuate neuroinflammation after release from damaged cells. In contrast, Inter‐alpha Inhibitor Proteins (IAIPs) are proteins with immunomodulatory effects including inhibition of pro‐inflammatory cytokines. We have demonstrated that IAIPs exhibit neuroprotective properties in neonatal rats exposed to hypoxic‐ischemic (HI) brain injury. In addition, previous studies have suggested that the light chain of IAIPs, bikunin, may exert its anti‐inflammatory effects by inhibiting HMGB1 in a variety of different injury models in adult subjects. The objectives of the current study were to confirm whether HMGB1 is a target of IAIPs by investigating the potential binding characteristics of HMGB1 and IAIPs in vitro, and co‐localization in vivo in cerebral cortices after exposure to HI injury. Solid‐phase binding assays and surface plasmon resonance (SPR) were used to determine the physical binding characteristics between IAIPs and HMGB1. Cellular localizations of IAIPs‐HMGB1 in neonatal rat cortex were visualized by double labeling with anti‐IAIPs and anti‐HMGB1 antibodies. Solid‐phase binding and SPR demonstrated specific binding between IAIPs and HMGB1 in vitro. Cortical cytoplasmic and nuclear co‐localization of IAIPs and HMGB1 were detected by immunofluorescent staining in control and rats immediately and 3 hours after HI. In conclusion, HMGB1 and IAIPs exhibit direct binding in vitro and co‐localization in vivo in neonatal rats exposed to HI brain injury suggesting HMGB1 could be a target of IAIPs.

Encephalopathy is a major cause of influenza-associated child death and severe neurological sequelae in Japan, highlighting the urgent need for new therapeutic strategies. In this study, we evaluated the effects of anti-high mobility group box-1 monoclonal antibody (α-HMGB1) treatment on brain edema induced by influenza A virus (IAV) and lipopolysaccharide in 4-week-old BALB/c female mice. The results showed that administration of 7.5 mg/kg α-HMGB1 1 h after IAV (A/Puerto Rico/8/34) inoculation significantly alleviated brain edema at 48 h after IAV inoculation, as confirmed by the suppression of Evans Blue dye leakage and matrix metallopeptidase-9 mRNA expression in the brain. Moreover, we also observed suppression of oxidative stress and different cytokines in IAV-inoculated mice. The expression of plasminogen activator inhibitor-1 was also attenuated following treatment with α-HMGB1. Notably, α-HMGB1 treatment had no effect on virus propagation in the lung. In summary, anti-HMGB1 treatment may improve the prognosis in cases with influenza-associated encephalopathy by attenuating brain edema and reducing the inflammatory responses induced by HMGB1.

Exposure to hypoxic-ischemic (HI) insults in newborns can predispose them to severe neurological sequela. The mechanisms underlying HI-related brain injury have not been completely elucidated. The neurovascular unit (NVU) is a composite of structures that protect the brain from the influx of detrimental molecules. Changes in the NVU after HI are important because they could reveal endogenous neuroprotective pathways in the cerebral microvasculature. Furthermore, the time course of changes in the NVU after exposure to HI in the newborn remains to be determined. In this study, we examined the effects of severe HI on the time course of changes in the NVU in neonatal rats. Brains were collected from rats exposed to right carotid artery ligation and 2 h of hypoxia on postnatal day 7 with recovery for 6 or 48 h after exposure to sham treatment (Sham) or HI. The right HI and left hypoxic alone sides of the brains were examined by quantitative immunohistochemistry for vascular density (laminin), pericyte vascular coverage (PDGFRβ), astrocyte vascular coverage (GFAP), and claudin-5 expression in the microvasculature of the cerebral cortex, white matter, and hippocampus. HI-related brain injury in neonatal rats was associated with increases in vascular density in the cortex and hippocampus 48 h after HI as well as neurovascular remodeling, including loss of pericyte coverage in the cortex and increases in claudin-5 in the hippocampus 6 h after HI. Astrocyte coverage was not affected by HI injury. The time course of the responses in the different components of the NVU varied after exposure to HI. There were also differential regional responses in the elements of the NVU in response to HI and hypoxia alone.

Acute flaccid myelitis (AFM) is a recently defined clinical disease accompanied by the national outbreak of enterovirus D68 (EV-D68) in the United States during the late summer/fall of 2014; 258 cases of EV-D68 and 59 cases of AFM were reported in Japan during the late summer/fall of 2015. Subsequently, there have been no epidemics of AFM or EV-D68. However, we encountered a patient who had AFM associated with EV-D68 in 2017. This is the first case of AFM caused by EV-D68 after the 2015 epidemic, and the only reported case in 2017. This report indicates that AFM caused by EV-D68 can arise even in non-epidemic situations. If a patient presents with paralysis, AFM caused by EV-D68 should be included in the differential diagnosis, regardless of the absence of an epidemic of EV-D68 infection.

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Inter-alpha Inhibitor Proteins (IAIPs) are key immunomodulatory molecules. Endogenous IAIPs are present in human, rodent, and sheep brains, and are variably localized to the cytoplasm and nuclei at multiple developmental stages. We have previously reported that ischemia-reperfusion (I/R) reduces IAIP concentrations in the fetal sheep brain. In this study, we examined the effect of I/R on total, cytoplasmic, and nuclear expression of IAIPs in neurons (NeuN+), microglia (Iba1+), oligodendrocytes (Olig2+) and proliferating cells (Ki67+), and their co-localization with histones and the endoplasmic reticulum in fetal brain cells. At 128 days of gestation, fetal sheep were exposed to Sham (n = 6) or I/R induced by cerebral ischemia for 30 min with reperfusion for 7 days (n = 5). Although I/R did not change the total number of IAIP+ cells in the cerebral cortex or white matter, cells with IAIP+ cytoplasm decreased, whereas cells with IAIP+ nuclei increased in the cortex. I/R reduced total neuronal number but did not change the IAIP+ neuronal number. The proportion of cytoplasmic IAIP+ neurons was reduced, but there was no change in the number of nuclear IAIP+ neurons. I/R increased the number of microglia and decreased the total numbers of IAIP+ microglia and nuclear IAIP+ microglia, but not the number of cytoplasmic IAIP+ microglia. I/R was associated with reduced numbers of oligodendrocytes and increased proliferating cells, without changes in the subcellular IAIP localization. IAIPs co-localized with the endoplasmic reticulum and histones. In conclusion, I/R alters the subcellular localization of IAIPs in cortical neurons and microglia but not in oligodendrocytes or proliferating cells. Taken together with the known neuroprotective effects of exogenous IAIPs, we speculate that endogenous IAIPs may play a role during recovery from I/R.