Lan Wan Wang

JNK signaling is the shared pathway linking neuroinflammation, blood-brain barrier disruption, and oligodendroglial apoptosis in the white matter injury of the immature brain.

BackgroundWhite matter injury is the major form of brain damage in very preterm infants. Selective white matter injury in the immature brain can be induced by lipopolysaccharide (LPS)-sensitized hypoxic-ischemia (HI) in the postpartum (P) day 2 rat pups whose brain maturation status is equivalent to that in preterm infants less than 30 weeks of gestation. Neuroinflammation, blood–brain barrier (BBB) damage and oligodendrocyte progenitor apoptosis may affect the susceptibility of LPS-sensitized HI in white matter injury. c-Jun N-terminal kinases (JNK) are important stress-responsive kinases in various forms of insults. We hypothesized that LPS-sensitized HI causes white matter injury through JNK activation-mediated neuroinflammation, BBB leakage and oligodendroglial apoptosis in the white matter of P2 rat pups.MethodsP2 pups received LPS (0.05 mg/kg) or normal saline injection followed by 90-min HI. Immunohistochemistry and immunoblotting were used to determine microglia activation, TNF-α, BBB damage, cleaved caspase-3, JNK and phospho-JNK (p-JNK), myelin basic protein (MBP), and glial fibrillary acidic protein (GFAP) expression. Immunofluorescence was performed to determine the cellular distribution of p-JNK. Pharmacological and genetic approaches were used to inhibit JNK activity.ResultsP2 pups had selective white matter injury associated with upregulation of activated microglia, TNF-α, IgG extravasation and oligodendroglial progenitor apoptosis after LPS-sensitized HI. Immunohistochemical analyses showed early and sustained JNK activation in the white matter at 6 and 24 h post-insult. Immunofluorescence demonstrated upregulation of p-JNK in activated microglia, vascular endothelial cells and oligodendrocyte progenitors, and also showed perivascular aggregation of p-JNK-positive cells around the vessels 24 h post-insult. JNK inhibition by AS601245 or by antisense oligodeoxynucleotides (ODN) significantly reduced microglial activation, TNF-α immunoreactivity, IgG extravasation, and cleaved caspase-3 in the endothelial cells and oligodendrocyte progenitors, and also attenuated perivascular aggregation of p-JNK-positive cells 24 h post-insult. The AS601245 or JNK antisense ODN group had significantly increased MBP and decreased GFAP expression in the white matter on P11 than the vehicle or scrambled ODN group.ConclusionsLPS-sensitized HI causes white matter injury through JNK activation-mediated upregulation of neuroinflammation, BBB leakage and oligodendrocyte progenitor apoptosis in the immature brain.

Overweight worsens apoptosis, neuroinflammation and blood-brain barrier damage after hypoxic ischemia in neonatal brain through JNK hyperactivation.

BackgroundApoptosis, neuroinflammation and blood-brain barrier (BBB) damage affect the susceptibility of the developing brain to hypoxic-ischemic (HI) insults. c-Jun N-terminal kinase (JNK) is an important mediator of insulin resistance in obesity. We hypothesized that neonatal overweight aggravates HI brain damage through JNK hyperactivation-mediated upregulation of neuronal apoptosis, neuroinflammation and BBB leakage in rat pups.MethodsOverweight (OF) pups were established by reducing the litter size to 6, and control (NF) pups by keeping the litter size at 12 from postnatal (P) day 1 before HI on P7. Immunohistochemistry and immunoblotting were used to determine the TUNEL-(+) cells and BBB damage, cleaved caspase-3 and poly (ADP-ribose) polymerase (PARP), and phospho-JNK and phospho-BimEL levels. Immunofluorescence was performed to determine the cellular distribution of phospho-JNK.ResultsCompared with NF pups, OF pups had a significantly heavier body-weight and greater fat deposition on P7. Compared with the NF-HI group, the OF-HI group showed significant increases of TUNEL-(+) cells, cleaved levels of caspase-3 and PARP, and ED1-(+) activated microglia and BBB damage in the cortex 24 hours post-HI. Immunofluorescence of the OF-HI pups showed that activated-caspase 3 expression was found mainly in NeuN-(+) neurons and RECA1-(+) vascular endothelial cells 24 hours post-HI. The OF-HI group also had prolonged escape latency in the Morris water maze test and greater brain-volume loss compared with the NF-HI group when assessed at adulthood. Phospho-JNK and phospho-BimEL levels were higher in OF-HI pups than in NF-HI pups immediately post-HI. JNK activation in OF-HI pups was mainly expressed in neurons, microglia and vascular endothelial cells. Inhibiting JNK activity by AS601245 caused more attenuation of cleaved caspase-3 and PARP, a greater reduction of microglial activation and BBB damage post-HI, and significantly reduced brain damage in OF-HI than in NF-HI pups.ConclusionsNeonatal overweight increased HI-induced neuronal apoptosis, microglial activation and BBB damage, and aggravated HI brain damage in rat pups through JNK hyperactivation.

Low-dose lipopolysaccharide selectively sensitizes hypoxic ischemia-induced white matter injury in the immature brain

Little is known about roles of inflammation and hypoxic ischemia (HI) in the generation of neuroinflammation and damage of blood-brain barrier (BBB) in the white matter (WM) that displays regional vulnerability in preterm infants. We investigated whether low-dose lipopolysaccharide (LPS) sensitizes HI-induced WM injury in postpartum (P) day 2 rat pups by selectively increasing neuroinflammation and BBB damage in the WM. Pups received LPS (0.05 mg/kg) (LPS + HI) or normal saline (NS + HI) followed by 90-min HI. LPS and NS group were the pups that had LPS or NS only. Myelin basic protein immunohistochemistry on P11 showed WM injury in LPS + HI group, but not in NS + HI, LPS, and NS groups. In contrast, no gray matter injury was found in the four groups. LPS + HI group also showed decreased number of oligodendrocytes in the WM 72-h postinsult. In the same brain region, increases of activated microglia, TNF-α expression, BBB leakage, and cleaved caspase-3 positive cells were much more prominent in LPS + HI group than in the other three groups 24-h postinsult. The oligodendrocytes were the major cells with cleaved caspase-3 expression. We concluded that low-dose LPS sensitized HI-induced WM injury in the immature brain by selectively up-regulating neuroinflammation and BBB damage in the WM.

Preterm infants of educated mothers have better outcome.

Aim: To determine the developmental trajectories of very‐low‐birthweight (VLBW) infants during the first 2 years of life, and investigate the most contributory predictors of diverse trajectories.

Hypoxic/Ischemic and Infectious Events Have Cumulative Effects on the Risk of Cerebral Palsy in Very-Low-Birth-Weight Preterm Infants

Background: Hypoxia/ischemia and inflammation are two major mechanisms for cerebral palsy (CP) in preterm infants. Objective: To investigate whether hypoxia/ischemia- and infection-related events in the perinatal and neonatal periods had cumulative effects on CP risk in very-low-birth-weight (VLBW) premature infants. Methods: From 1995 to 2005, 5,807 VLBW preterm infants admitted to Taiwan hospitals were enrolled. The cumulative effects of hypoxic/ischemic and infectious events during the perinatal and neonatal periods on CP risk at corrected age 24 months were analyzed. Results: Of the 4,355 infants with 24-month follow-up, 457 (10.5%) had CP. The CP group had significantly higher incidences of hypoxia/ischemia-related events in the perinatal and neonatal periods, and sepsis in the neonatal period than the normal group. Three hypoxic/ischemic events, including birth cardiopulmonary resuscitation (OR 2.25; 95% CI 1.81-2.82), patent ductus arteriosus (PDA) ligation (2.94; 1.35-5.75) and chronic lung disease (3.14; 2.61-3.85) had the most significant contribution to CP. Relative to CP risk for infants with neither the three hypoxic/ischemic events nor sepsis, the CP odds increased 1.98-, 2.26- and 2.15-fold for infants with birth cardiopulmonary resuscitation, PDA ligation and chronic lung disease, respectively; while the combination with sepsis further increased the odds to 3.18-, 3.83- and 3.25-fold, respectively. Using the three hypoxic/ischemic events plus sepsis, CP rates were 10.0, 16.7, 26.7, 40.0 and 54.7% for infants with none, one, two, three and four events, respectively. Conclusions: Hypoxic/ischemic and infectious events across the perinatal and neonatal periods exerted cumulative effects on CP risk in VLBW premature infants.

Human Umbilical Vein Endothelial Cells Protect Against Hypoxic-Ischemic Damage in Neonatal Brain via Stromal Cell-derived Factor 1/C-X-C Chemokine Receptor Type 4

Background and Purpose— Agents that protect against neurovascular damage provide a powerful neuroprotective strategy. Human umbilical vein endothelial cells (HUVECs) may be used to treat neonates with hypoxic-ischemia (HI) because of its autologous capability. We hypothesized that peripherally injected HUVECs entered the brain after HI, protected against neurovascular damage, and provided protection via stromal cell–derived factor 1/C-X-C chemokine receptor type 4 pathway in neonatal brain. Methods— Postpartum day 7 rat pups received intraperitoneal injections of low-passage HUVEC-P4, high-passage HUVEC-P8, or conditioned medium before and immediately after HI. HUVECs were transfected with adenovirus-green fluorescent protein for cell tracing. Oxygen–glucose deprivation was established by coculturing HUVEC-P4 with mouse neuroblastoma neuronal cells (Neuro-2a) and with mouse immortalized cerebral vascular endothelial cells (b.End3). Results— HUVEC-P4–treated group had more blood levels of green fluorescent protein–positive cells than HUVEC-P8–treated group 3 hours postinjection. Intraperitoneally injected HUVEC-P4, but not HUVEC-P8, entered the cortex after HI and positioned closed to the neurons and microvessels. Compared with the condition medium–treated group, the HUVEC-P4–treated but not the HUVEC-P8–treated group showed significantly less neuronal apoptosis and blood–brain barrier damage and more preservation of microvessels in the cortex 24 hours after HI. On postpartum day 14, the HUVEC-P4–treated group showed significant neuroprotection compared with the condition medium–treated group. Stromal cell–derived factor 1 was upregulated in the ipsilateral cortex 3 hours after HI, and inhibiting the stromal cell–derived factor 1/C-X-C chemokine receptor type 4 reduced the protective effect of HUVEC-P4. In vitro transwell coculturing of HUVEC-P4 also significantly protected against oxygen–glucose deprivation cell death in neurons and endothelial cells. Conclusions— Cell therapy using HUVECs may provide a powerful therapeutic strategy in treating neonates with HI.

Tc-99m-HL91 imaging in the early detection of neuronal injury in a neonatal rat model of hypoxic ischemia

Objective:Hypoxic-ischemic insult in newborns results in progressive neuronal loss. For neuroprotective therapy to be effective, it is important to identify high-risk neonates soon after birth. 99mTc-labeled imaging agent, Tc-99m-HL91, developed as a putative hypoxic reagent, has been reported to demonstrate increased uptake in ischemic myocardium. We hypothesized that Tc-99m-HL91 is sensitive for the early identification of hypoxic-ischemic injury in neonatal rat brains. Design:Laboratory investigation. Setting:University research laboratory. Subjects:Sprague-Dawley rat pups. Interventions:Postnatal day-7 pups were divided into four groups: hypoxic-ischemia, hypoxia-only, ischemia-only, and controls. In the early (2 hrs), intermediate (20 hrs), and late (44 hrs) reoxygenation phases, Tc-99m-HL91 in vivo and ex vivo imaging and quantitative autoradiography were performed. Regions of interest were drawn to calculate the contrast ratio of Tc-99m-HL91 uptake between the ipsilateral and contralateral hemispheres. Pathology, cerebral blood flow, and blood-brain barrier damage were determined. Measurements and Main Results:After hypoxic-ischemia, there were very few pyknotic neurons in the early phase, many pyknotic neurons in the intermediate phase, and extensive neuronal loss in the late phase postreoxygenation. Blood-brain barrier damage occurred in the early phase, progressed in the intermediate phase, and became extensive in the late phase. The hypoxia-only and ischemia-only pups showed no neuronal or blood-brain barrier damage and had higher cerebral blood flow postreoxygenation compared with the hypoxia-ischemia pups. Regions of interest analysis of in vivo and ex vivo images and autoradiography revealed significantly higher Tc-99m-HL91 contrast ratio at early and intermediate phases, not late phase of hypoxic-ischemic group. Hypoxic-ischemia group had significantly higher contrast ratio values in the early and intermediate phases than the hypoxia-only and ischemia-only groups. A contrast ratio value of 0.15 in the early phase on postnatal day 7 had a sensitivity of 0.95 and specificity of 0.89 in detecting significant hypoxic-ischemic lesions on postnatal day 21. Conclusion:Tc-99m-HL91 uptake is sensitive for the early detection of hypoxic-ischemic injury in neonatal brains.

Validity of the Clinical Adaptive Test (CAT)/Clinical Linguistic and Auditory Milestone Scale (CLAMS) as a screening instrument for very low birth weight infants in Taiwan.

ABSTRACT. The authors investigated the validity of the Clinical Adaptive Test (CAT)/Clinical Linguistic and Auditory Milestone Scale (CLAMS) for developmental screening and early prediction in very low birth weight (VLBW) infants, using the Bayley Scales of Infant Development II (BSID-II) as a reference standard. A total of 808 VLBW infants discharged from neonatal intensive care units in Taiwan from January 1995 to December 1997 were enrolled and followed up at the corrected ages of 6, 12, 18, and 24 months. The CAT/CLAMS and BSID-II were performed separately during each visit. The CAT/CLAMS showed strong concurrent correlations (r = 0.51-0.86, p < .0001) with BSID-II mental developmental index (MDI), and had high conegativity scores (96.7%-100%) but low copositivity scores (30.0%-45.3%) for detecting developmental delay. At 24 months of age, the CAT/CLAMS had better predictive validity for significant (MDI <70) rather than borderline (MDI = 70-84) developmental delay. The authors conclude that the CAT/CLAMS is not an appropriate developmental instrument for screening and early prediction in VLBW infants in Taiwan.

Postnatal Steroids and Febrile Seizure Susceptibility in Preterm Children.

OBJECTIVE: To investigate risk factors, seizure characteristics, and outcomes of febrile seizure (FS) in children born very preterm. METHODS: This study used a prospective registry data set of 844 preterm infants (birth weight <1500 g and gestational age <32 weeks) admitted to NICUs from 2001 to 2009 in southern Taiwan. We investigated the prevalence, risks, seizure patterns, and outcomes of FS in children aged 5 years. RESULTS: Among 575 children (follow-up rate, 85.8%) followed up for 5 years, 35 (6.1%) developed FS. The FS and non-FS groups were comparable regarding their mean gestational age, birth weight, 5-minute Apgar score <6, and prenatal and postnatal complications. No difference was observed in the use of prenatal corticosteroids between the 2 groups. The FS group had a significantly higher rate of postnatal corticosteroid treatment than the non-FS group, even after adjusting for confounding factors (odds ratio, 5.4 [95% confidence interval, 1.9–15.8]; P = .006). No differences were observed in IQs or subsequent epilepsy rates between the 2 groups. Although no difference was observed in the age of FS onset or neurodevelopmental outcomes between the 2 groups, children with FS who received postnatal corticosteroid treatment had a significantly lower mean body temperature during the first FS attack compared with those who did not receive postnatal corticosteroid treatment (38.6 ± 0.4°C vs 39.2 ± 0.6°C; P = .034). CONCLUSIONS: Children born very preterm have a higher rate of FS, and postnatal corticosteroid treatment was associated with FS susceptibility in these children.

Age-dependent vulnerability of cyclosporine-associated encephalopathy in children

INTRODUCTION Cyclosporine (CsA) is an immunosuppressant known for its neurotoxicity, which presents with acute encephalopathy and seizures in the most severe form. However, whether there is age-related neurological susceptibility in pediatric population is poorly defined. The study aims to examine the vulnerability of CsA neurotoxicity among different age groups of pediatric patients in terms of occurrence rate, acute presentations, long-term outcomes, and neuroimaging findings. METHODS Pediatric patients (age <18 years) who received CsA in a tertiary referral center between July 1, 1988 and August 31, 2011 were retrospectively reviewed for CsA-related encephalopathy. The clinical presentations, demographic data, and laboratory examinations were analyzed through t-test for numerical and Fishers exact test for categorical variables. Exact logistic regression was used to examine the effect of each variables. RESULTS Twelve (8%) of the enrolled 146 patients developed CsA-induced encephalopathy. Compared to the non-neurotoxicity group, the neurotoxicity group was significantly younger upon starting CsA (p = 0.008) and had higher percentages of hypertension after CsA treatment (p = 0.01). Regression analysis showed that age <6 years (OR 7.6, 95% CI 1.6-51.5; p = 0.007) and hypertension after CsA (OR 6.3, 95% CI 1.4-35.4; p = 0.016) were significantly associated with CsA encephalopathy. Younger children were prone to have more severe seizures in the acute stage and more epilepsy and neuropsychiatric disorders in the future. Follow-up neuroimaging showed parietal cerebral atrophy in all examined children <6 years of age. CONCLUSIONS Age-dependent susceptibility of CsA neurotoxicity occurs in children, with severe acute presentations and long-term sequelae in children below 6 years old.