High-mobility group box-1 and inter-alpha inhibitor proteins: In vitro binding and co-localization in cerebral cortex after hypoxic-ischemic injury

Prognostic value of serum high-mobility group box 1 in neonates with neonatal encephalopathy

BACKGROUND

This study aimed to investigate the diagnostic potential of serum high-mobility group box 1 (HMGB1) in neonatal encephalopathy (NE).

METHODS

A retrospective study was conducted, analyzing 216 neonates diagnosed with NE. The neonates were divided into two groups based on their outcomes at 28 days. Serum HMGB1 levels were compared between the two groups. ROC analysis was used to determine the predictive value of HMGB1.

RESULTS

At 28 days, 174 infants had a good prognosis, while 42 had a poor prognosis. Infants with a poor prognosis had higher serum HMGB1 concentrations within 24 h of birth. Multifactorial analysis revealed that extremely preterm birth, extremely low birth weight, an Apgar score of 0-3 at 5 min, premature rupture of membranes by the mother, moderate to severe NE, and serum HMGB1 > 6.14 ng/mL are independent risk factors for poor prognosis. HMGB1 has predictive value for short-term prognosis with an area under the curve of 0.79. Elevated HMGB1 levels in the acute phase of NE are associated with poor short-term neonatal outcomes. The decrease in HMGB1 concentrations over time correlates with a good prognosis; whereas an increase suggests a poor prognosis.

CONCLUSION

Early measurement of serum HMGB1 could aid in the prognostic assessment of neonates with NE.

IMPACT STATEMENT

Although serum HMGB1 has emerged as a potential predictor of neonatal outcomes in neonatal encephalopathy, the relationship of HMGB1 levels to neonatal encephalopathy severity remains unclear. The current results demonstrate that infants with a poor prognosis had higher serum HMGB1 concentrations within 24 h of birth. Importantly, elevated serum HMGB1 levels in the acute phase of neonatal encephalopathy are associated with poor short-term neonatal outcomes. Our findings reveal the clinical values of HMGB1 in the prediction of neonatal outcomes in NE patients.

Association between decreased cord blood inter-alpha inhibitor levels and neonatal encephalopathy at birth

BACKGROUND

Inter-alpha inhibitor proteins (IAIPs) are structurally related proteins found in the systemic circulation with immunomodulatory anti-inflammatory properties. Reduced levels are found in inflammatory related conditions including sepsis and necrotizing enterocolitis, and in neonatal rodents after exposure to hypoxia ischemia. In the current study, cord blood IAIP levels were measured in neonates with and without exposure to hypoxic-ischemic encephalopathy (HIE).

METHODS

This is a prospective cohort study including infants born ≥36 weeks over a one-year period. Term pregnancies were divided into two groups: a "reference control" (uncomplicated term deliveries), and "moderate to severe HIE" (qualifying for therapeutic hypothermia). IAIPs were quantified using a sensitive ELISA on the cord blood samples.

RESULTS

The study included 57 newborns: Reference control group (n = 13) and moderate/severe HIE group (n = 44). Measurement of IAIP cord blood concentrations in moderate to severe HIE group [278.2 (138.0, 366.0) μg/ml] revealed significantly lower IAIP concentrations compared with the control group [418.6 (384.5, 445.0) μg/ml] (p = 0.002).

CONCLUSIONS

These findings suggest a potential role for IAIPs as indicators of neonates at risk for HIE. IAIP levels could have diagnostic implications in the management of HIE. Future research is required to explore the relationship between HIE and IAIPs as biomarkers for disease severity.

CATEGORY OF STUDY

Translational.

Neuroprotective efficacy of hypothermia and Inter-alpha Inhibitor Proteins after hypoxic ischemic brain injury in neonatal rats

Therapeutic hypothermia is the standard of care for hypoxic-ischemic (HI) encephalopathy. Inter-alpha Inhibitor Proteins (IAIPs) attenuate brain injury after HI in neonatal rats. Human (h) IAIPs (60 ​mg/kg) or placebo (PL) were given 15 ​min, 24 and 48 ​h to postnatal (P) day-7 rats after carotid ligation and 8% oxygen for 90 ​min with (30 ​°C) and without (36 ​°C) exposure to hypothermia 1.5 ​h after HI for 3 ​h. Hemispheric volume atrophy (P14) and neurobehavioral tests including righting reflex (P8-P10), small open field (P13-P14), and negative geotaxis (P14) were determined. Hemispheric volume atrophy in males was reduced (P ​< ​0.05) by 41.9% in the normothermic-IAIP and 28.1% in the hypothermic-IAIP compared with the normothermic-PL group, and in females reduced (P ​< ​0.05) by 30.3% in the normothermic-IAIP, 45.7% in hypothermic-PL, and 55.2% in hypothermic-IAIP compared with the normothermic-PL group after HI. Hypothermia improved (P ​< ​0.05) the neuroprotective effects of hIAIPs in females. The neuroprotective efficacy of hIAIPs was comparable to hypothermia in female rats (P ​= ​0.183). Treatment with hIAIPs, hypothermia, and hIAIPs with hypothermia decreased (P ​< ​0.05) the latency to enter the peripheral zone in the small open field test in males. We conclude that hIAIPs provide neuroprotection from HI brain injury that is comparable to the protection by hypothermia, hypothermia increases the effects of hIAIPs in females, and hIAIPs and hypothermia exhibit some sex-related differential effects.

Novel aspects of sepsis pathophysiology: NETs, plasma glycoproteins, endotheliopathy and COVID-19

In 2016, sepsis was newly defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis remains one of the crucial medical problems to be solved worldwide. Although the world health organization has made sepsis a global health priority, there remain no specific and effective therapy for sepsis so far. Indeed, over the previous decades almost all attempts to develop novel drugs have failed. This may be partly ascribable to the multifactorial complexity of the septic cascade and the resultant difficulties of identifying drug targets. In addition, there might still be missing links among dysregulated host responses in vital organs. In this review article, recent advances in understanding of the complex pathophysiology of sepsis are summarized, with a focus on neutrophil extracellular traps (NETs), the significant role of NETs in thrombosis/embolism, and the functional roles of plasma proteins, histidine-rich glycoprotein (HRG) and inter-alpha-inhibitor proteins (IAIPs). The specific plasma proteins that are markedly decreased in the acute phase of sepsis may play important roles in the regulation of blood cells, vascular endothelial cells and coagulation. The accumulating evidence may provide us with insights into a novel aspect of the pathophysiology of sepsis and septic ARDS, including that in COVID-19.

Serum Relmβ combined with abdominal signs may predict surgical timing in neonates with NEC: A cohort study

AIMS

To examine the predictive value of serum biomarkers combined with other indicators for necrotizing enterocolitis (NEC) surgery decision-making.

METHODS

Clinical data, including baseline information, clinical features, imaging presentation and serum assessment, of the infants enrolled were collected, and the serum concentrations of HBD2, HMGB-1, Claudin-3 and Relmβ were determined. Student's t test, the Mann-Whitney U test, the chi-square test and logistic regression analysis were used. Receiver operating characteristic (ROC) curves were also generated.

RESULTS

Forty-nine infants were enrolled, with 23 in the surgical NEC group and 26 in the medical NEC group. There were no differences in the baseline clinical information, including birth weight, gestational age, admission age and risk factors, during pregnancy and before enrollment (P > 0.05). Peritonitis, intestinal adhesion and sepsis were more common in the surgical group (P < 0.05). The incidences of abdominal distention, abdominal wall tenseness, abdominal tenderness and absent bowel sounds in the surgical group were significantly higher when NEC occurred (P < 0.05). There were no differences between the two groups in the imaging presentation (P > 0.05). The concentration of Relmβ {[8.66 (4.29, 19.28) vs. 20.65 (9.51, 44.65)]} in the surgical group was significantly higher (P < 0.05). Abdominal wall tenseness, abdominal tenderness and a Relmβ concentration > 19.7 μmol/L were included in the predictive model, and the AUC of the predictive score was 0.943 (95% CI: 0.891-1.000) (P < 0.05).

CONCLUSION

Serum Relmβ concentration combined with abdominal wall tenseness and abdominal tenderness may be useful in determining surgical timing in neonates with NEC.

MiR-582-5p attenuates neonatal hypoxic-ischemic encephalopathy by targeting high mobility group box 1 (HMGB1) through inhibiting neuroinflammation and oxidative stress

BACKGROUND

MiR-582-5p has been demonstrated to protect against ischemic stroke. However, its implication in the progression of neonatal hypoxic-ischemic encephalopathy (HIE) has not been explored.

METHODS

In this study, we used an in vitro model of oxygen-glucose deprivation (OGD) to investigate the protective effect of miR-582-5p on PC12 cells. OGD-induced inhibition of cell viability and promotion of cell death was assessed by CCK-8 assay and flow cytometry. Real-time PCR and enzyme-linked immunosorbent assay (ELISA) were utilized to examine the levels of inflammatory cytokines. The effects of miR-582-5p on OGD-induced oxidative injury were assessed by the determination of oxidative stress indicators. Furthermore, dual-luciferase reporter assay and gain-offunction assay were used to determine the mechanism of miR-582-5p in OGD-induced cell injury.

RESULTS

The expression of miR-582-5p was reduced upon OGD treatment in PC12 cells. Overexpression of miR-582-5p inhibited OGD-induced PC12 cell injury by regulating cell viability, apoptosis, inflammatory responses, and oxidative stress. MiR-582-5p targeted and negatively regulated high mobility group box 1 (HMGB1). MiR-582-5p presented protective effects on OGD-induced PC12 cell injury by targeting HMGB1.

CONCLUSION

Our results indicated that miR-582-5p ameliorates neuronal injury by inhibiting apoptosis, inflammation, and oxidative stress through targeting HMGB1.

Changes in Cellular Localization of Inter-Alpha Inhibitor Proteins after Cerebral Ischemia in the Near-Term Ovine Fetus

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.