Perinatal Asphyxia May Influence the Level of Beta-Amyloid (1-42) in Cerebrospinal Fluid: An Experimental Study on Newborn Pigs

A comparative proteomic analysis for non-invasive early prediction of hypoxic-ischemic injury in asphyxiated neonates

AIM

Hypoxic Ischemic Encephalopathy (HIE) is one of the principal causes of neonatal mortality and long-term morbidity worldwide. The neonatal signs of mild cerebral injury are subtle, making an early precise diagnosis difficult. Delayed detection, poor prognosis, and lack of specific biomarkers for the disease are increasing mortality rates. In this study, we intended to identify specific biomarkers using comparative proteomic analysis to predict the severity of perinatal asphyxia so that its outcome can also be prevented.

EXPERIMENTAL DESIGN

A case-control study was conducted on 38 neonates, and urine samples were collected within 24 and 72 h of life. A tandem mass spectrometry-based quantitative proteomics approach, followed by validation via sandwich ELISA, was performed.

RESULTS

The LC-MS/MS-based proteomics analysis resulted in the identification of 1201 proteins in urine, with 229, 244, and 426 being differentially expressed in HIE-1, HIE-2, and HIE-3, respectively. Axon guidance, Diseases of programmed cell death, and Detoxification of reactive oxygen species pathways were significantly enriched in mild HIE versus severe HIE. Among the differentially expressed proteins in various stages of HIE, we chose to validate four proteins - APP, AGT, FABP1, and FN1 - via sandwich ELISA. Individual and cumulative ROC curves were plotted. AGT and FABP1 together showed high sensitivity, specificity, and accuracy as potential biomarkers for early diagnosis of HIE.

CONCLUSION

Establishing putative urinary biomarkers will facilitate clinicians to more accurately screen neonates for brain injury and monitor the disease progression. Prompt treatment of neonates may reduce mortality and neurodevelopmental impairment.

Gene expression in the intestine of newborn piglets after hypoxia-reoxygenation

BACKGROUND

In preterm infants, intestinal hypoxia may partly contribute to the pathophysiology of necrotizing enterocolitis through changes in gene expression. Splanchnic hypoxia can be detected with monitoring of regional splanchnic oxygen saturation (rsSO2). Using a piglet model of asphyxia, we aimed to correlate changes in rsSO2 to gene expression.

METHODS

Forty-two newborn piglets were randomized to control or intervention groups. Intervention groups were subjected to hypoxia until they were acidotic and hypotensive. Next, they were reoxygenated for 30 min according to randomization, i.e., 21% O2, 100% O2, or 100% O2 for 3 min followed by 21% O2, and observed for 9 h. We continuously measured rsSO2 and calculated mean rsSO2 and variability of rsSO2 (rsCoVar = SD/mean). Samples of terminal ileum were analyzed for mRNA expression of selected genes related to inflammation, erythropoiesis, fatty acid metabolism, and apoptosis.

RESULTS

The expression of selected genes was not significantly different between control and intervention groups. No associations between mean rsSO2 and gene expression were observed. However, lower rsCoVar was associated with the upregulation of apoptotic genes and the downregulation of inflammatory genes (P < 0.05).

CONCLUSION

Our study suggests that hypoxia and reoxygenation cause reduced vascular adaptability, which seems to be associated with the upregulation of apoptosis and downregulation of inflammation.

IMPACT

Our results provide important insight into the (patho)physiological significance of changes in the variability of rsSO2. Our findings may advance future research and clinical practice regarding resuscitation strategies of preterm infants.

Long Non-Coding RNAs in Hypoxia and Oxidative Stress: Novel Insights Investigating a Piglet Model of Perinatal Asphyxia

Birth asphyxia is the leading cause of death and disability in young children worldwide. Long non-coding RNAs (lncRNAs) may provide novel targets and intervention strategies due to their regulatory potential, as demonstrated in various diseases and conditions. We investigated cardinal lncRNAs involved in oxidative stress, hypoxia, apoptosis, and DNA damage using a piglet model of perinatal asphyxia. A total of 42 newborn piglets were randomized into 4 study arms: (1) hypoxia–normoxic reoxygenation, (2) hypoxia–3 min of hyperoxic reoxygenation, (3) hypoxia–30 min of hyperoxic reoxygenation, and (4) sham-operated controls. The expression of lncRNAs BDNF-AS, H19, MALAT1, ANRIL, TUG1, and PANDA, together with the related target genes VEGFA, BDNF, TP53, HIF1α, and TNFα, was assessed in the cortex, the hippocampus, the white matter, and the cerebellum using qPCR and Droplet Digital PCR. Exposure to hypoxia–reoxygenation significantly altered the transcription levels of BDNF-AS, H19, MALAT1, and ANRIL. BDNF-AS levels were significantly enhanced after both hypoxia and subsequent hyperoxic reoxygenation, 8% and 100% O2, respectively. Our observations suggest an emerging role for lncRNAs as part of the molecular response to hypoxia-induced damages during perinatal asphyxia. A better understanding of the regulatory properties of BDNF-AS and other lncRNAs may reveal novel targets and intervention strategies in the future.

Assessing nuclear versus mitochondrial cell-free DNA (cfDNA) by qRT-PCR and droplet digital PCR using a piglet model of perinatal asphyxia

BACKGROUND

Since the discovery more than half a century ago, cell-free DNA (cfDNA) has become an attractive objective in multiple diagnostic, prognostic, and monitoring settings. However, despite the increasing number of cfDNA applications in liquid biopsies, we still lack a comprehensive understanding of the nature of cfDNA including optimal assessment. In the presented study, we continued testing and validation of common techniques for cfDNA extraction and quantification (qRT-PCR or droplet digital PCR) of nuclear- and mitochondrial cfDNA (ncfDNA and mtcfDNA) in blood, using a piglet model of perinatal asphyxia to determine potential temporal and quantitative changes at the levels of cfDNA.

METHODS AND RESULTS

Newborn piglets (n = 19) were either exposed to hypoxia (n = 11) or were part of the sham-operated control group (n = 8). Blood samples were collected at baseline (= start) and at the end of hypoxia or at 40-45 min for the sham-operated control group. Applying the qRT-PCR method, ncfDNA concentrations in piglets exposed to hypoxia revealed an increasing trend from 7.1 ng/ml to 9.5 ng/ml for HK2 (hexokinase 2) and from 4.6 ng/ml to 7.9 ng/ml for β-globulin, respectively, whereas the control animals showed a more balanced profile. Furthermore, median levels of mtcfDNA were much higher in comparison to ncfDNA, but without significant differences between intervention versus the control group.

CONCLUSIONS

Both, qRT-PCR and the droplet digital PCR technique identified overall similar patterns for the concentration changes of cfDNA; but, the more sensitive digital PCR methodology might be required to identify minimal responses.

Melatonin: A Potential Candidate for the Treatment of Experimental and Clinical Perinatal Asphyxia

Perinatal asphyxia is considered to be one of the major causes of brain neurodegeneration in full-term newborns. The worst consequence of perinatal asphyxia is neurodegenerative brain damage, also known as hypoxic-ischemic encephalopathy. Hypoxic-ischemic encephalopathy is the leading cause of mortality in term newborns. To date, due to the complex mechanisms of brain damage, no effective or causal treatment has been developed that would ensure complete neuroprotection. Although hypothermia is the standard of care for hypoxic-ischemic encephalopathy, it does not affect all changes associated with encephalopathy. Therefore, there is a need to develop effective treatment strategies, namely research into new agents and therapies. In recent years, it has been pointed out that natural compounds with neuroprotective properties, such as melatonin, can be used in the treatment of hypoxic-ischemic encephalopathy. This natural substance with anti-inflammatory, antioxidant, anti-apoptotic and neurofunctional properties has been shown to have pleiotropic prophylactic or therapeutic effects, mainly against experimental brain neurodegeneration in hypoxic-ischemic neonates. Melatonin is a natural neuroprotective hormone, which makes it promising for the treatment of neurodegeneration after asphyxia. It is supposed that melatonin alone or in combination with hypothermia may improve neurological outcomes in infants with hypoxic-ischemic encephalopathy. Melatonin has been shown to be effective in the last 20 years of research, mainly in animals with perinatal asphyxia but, so far, no clinical trials have been performed on a sufficient number of newborns. In this review, we summarize the advantages and limitations of melatonin research in the treatment of experimental and clinical perinatal asphyxia.

Splanchnic oxygen saturation during reoxygenation with 21% or 100% O2 in newborn piglets

BACKGROUND

Increasing evidence recognizes the harm of excess oxygen to lungs, eyes, and brain of preterm infants, but not yet to the intestine. We assessed changes in splanchnic oxygenation during reoxygenation with 21% compared to 100% O₂ in a newborn piglet model of perinatal asphyxia.

METHODS

We randomized 25 piglets to control or intervention. Intervention groups underwent global hypoxia until acidosis and hypotension occurred. Piglets were reoxygenated for 30 min with 21% or 100% O₂ and observed for 9 h. We continuously measured regional splanchnic oxygen saturation (r_sSO₂) using near-infrared spectroscopy (NIRS). We calculated mean r_sSO₂ and r_sCoVar (as SD/mean). We measured PaO₂ and SaO₂, sampled from the right carotid artery.

RESULTS

Reoxygenation after global hypoxia restored r_sSO₂. Reoxygenation with 100% O₂ increased r_sSO₂ to values significantly higher than baseline. In intervention groups, r_sCoVar decreased during observation compared to baseline. We found a correlation between r_sSO₂ and PaO₂ (r = 0.420, P < 0.001) and between r_sSO₂ and SaO₂ (r = 0.648, P < 0.001) in pooled data from the entire experiment.

CONCLUSION

Reoxygenation after global hypoxia improves splanchnic oxygenation, but is associated with reduced variability of r_sSO₂. Reoxygenation with 100% O₂ exposes the intestine to hyperoxia. Splanchnic NIRS is able to detect intestinal hypoxia and hyperoxia.

IMPACT

Splanchnic oxygenation improves during reoxygenation after global hypoxia, though reoxygenation with 100% O₂ exposes the intestine to hyperoxia. Decreased variability of splanchnic oxygenation several hours after hypoxia and reoxygenation seems to be independent of the resuscitation strategy, and may indicate intestinal injury. Splanchnic NIRS monitoring was able to detect intestinal hypoxia and exposure to hyperoxia, as evidenced by a strong correlation between splanchnic oxygenation and arterial oxygen content.

Hypothermia after Perinatal Asphyxia Does Not Affect Genes Responsible for Amyloid Production in Neonatal Peripheral Lymphocytes

In this study, the expression of the genes of the amyloid protein precursor, β-secretase, presenilin 1 and 2 by RT-PCR in the lymphocytes of newborns after perinatal asphyxia and perinatal asphyxia treated with hypothermia was analyzed at the age of 15-21 days. The relative quantification of Alzheimer's-disease-related genes was first performed by comparing the peripheral lymphocytes of non-asphyxia control versus those with asphyxia or asphyxia with hypothermia. In the newborns who had perinatal asphyxia, the peripheral lymphocytes presented a decreased expression of the amyloid protein precursor and β-secretase genes. On the other hand, the expression of the presenilin 1 and 2 genes increased in the studied group. The expression of the studied genes in the asphyxia group treated with hypothermia had an identical pattern of changes that were not statistically significant to the asphyxia group. This suggests that the expression of the genes involved in the metabolism of the amyloid protein precursor in the peripheral lymphocytes may be a biomarker of progressive pathological processes in the brain after asphyxia that are not affected by hypothermia. These are the first data in the world showing the role of hypothermia in the gene changes associated with Alzheimer's disease in the peripheral lymphocytes of newborns after asphyxia.

Early-Life Environment Influence on Late-Onset Alzheimer’s Disease

With the expand of the population’s average age, the incidence of neurodegenerative disorders has dramatically increased over the last decades. Alzheimer disease (AD) which is the most prevalent neurodegenerative disease is mostly sporadic and primarily characterized by cognitive deficits and neuropathological lesions such as amyloid -β (Aβ) plaques and neurofibrillary tangles composed of hyper- and/or abnormally phosphorylated Tau protein. AD is considered a complex disease that arises from the interaction between environmental and genetic factors, modulated by epigenetic mechanisms. Besides the well-described cognitive decline, AD patients also exhibit metabolic impairments. Metabolic and cognitive perturbations are indeed frequently observed in the Developmental Origin of Health and Diseases (DOHaD) field of research which proposes that environmental perturbations during the perinatal period determine the susceptibility to pathological conditions later in life. In this review, we explored the potential influence of early environmental exposure to risk factors (maternal stress, malnutrition, xenobiotics, chemical factors … ) and the involvement of epigenetic mechanisms on the programming of late-onset AD. Animal models indicate that offspring exposed to early-life stress during gestation and/or lactation increase both AD lesions, lead to defects in synaptic plasticity and finally to cognitive impairments. This long-lasting epigenetic programming could be modulated by factors such as nutriceuticals, epigenetic modifiers or psychosocial behaviour, offering thus future therapeutic opportunity to protect from AD development.

Alzheimer's Disease Associated Presenilin 1 and 2 Genes Dysregulation in Neonatal Lymphocytes Following Perinatal Asphyxia

Perinatal asphyxia is mainly a brain disease leading to the development of neurodegeneration, in which a number of peripheral lesions have been identified; however, little is known about the expression of key genes involved in amyloid production by peripheral cells, such as lymphocytes, during the development of hypoxic-ischemic encephalopathy. We analyzed the gene expression of the amyloid protein precursor, β-secretase, presenilin 1 and 2 and hypoxia-inducible factor 1-α by RT-PCR in the lymphocytes of post-asphyxia and control neonates. In all examined periods after asphyxia, decreased expression of the genes of the amyloid protein precursor, β-secretase and hypoxia-inducible factor 1-α was noted in lymphocytes. Conversely, expression of presenilin 1 and 2 genes decreased on days 1–7 and 8–14 but increased after survival for more than 15 days. We believe that the expression of presenilin genes in lymphocytes could be a potential biomarker to determine the severity of the post-asphyxia neurodegeneration or to identify the underlying factors for brain neurodegeneration and get information about the time they occurred. This appears to be the first worldwide data on the role of the presenilin 1 and 2 genes associated with Alzheimer’s disease in the dysregulation of neonatal lymphocytes after perinatal asphyxia.

Transcriptome analysis reveals dysregulation of genes involved in oxidative phosphorylation in a murine model of retinopathy of prematurity

BACKGROUND

Retinal gene expression pattern is severely altered after exposition to hyperoxia in mice with oxygen-induced retinopathy (OIR), a common model of retinopathy of prematurity. Gene ontology and signaling pathway analyses may add new insights into a better understanding of the pathogenesis of this disease.

METHODS

Seven-day-old C57BL/6J mice (n = 60) were exposed to 75% oxygen for 5 days and then recovered in room air. The controls (n = 60) were kept in the normoxic conditions. Retinas were harvested immediately following hyperoxia, during the phase of maximal neovascularization, and at the time of neovascularization regression. The retinal RNA samples were evaluated for gene expression using mouse gene expression microarrays. DAVID annotation tools were used for gene ontology and pathway analyses.

RESULTS

The most significantly enriched signaling pathways during the neovascularization phase of OIR were: focal adhesion; ECM-receptor interaction; PI3K-Akt; oxidative phosphorylation; and Alzheimer's, Parkinson's and Huntington's disease signaling pathways. Genes involved in apoptosis, cell proliferation, cell differentiation, and immune responses were associated with neovascularization regression.

CONCLUSIONS

Performed analyses revealed the possible involvement of various signaling pathways in OIR pathomechanism, mostly specific to the OIR phase. Dysregulation of genes involved in oxidative phosphorylation may have an impact on neovascularization development.

Quantification of circulating cell-free DNA (cfDNA) in urine using a newborn piglet model of asphyxia

Cell free DNA (cfDNA) in plasma has been described as a potential diagnostic indicator for a variety of clinical conditions, including neonatal hypoxia. Neonatal hypoxia or perinatal asphyxia is a severe medical condition caused by a temporary interruption in oxygen availability during birth. Previously, we have reported temporal changes of cfDNA detected in blood in a newborn piglet model of perinatal asphyxia. However, cfDNA can also be found in other body liquids, opening for a less invasive diagnostic prospective. The objective of this study was to test and establish a reliable method for the isolation and quantification of cfDNA from urine and to explore changes in the quantities of cfDNA using a newborn piglet model of asphyxia. Animals were exposed to hypoxia-reoxygenation (n = 6), hypoxia-reoxygenation + hypothermia (n = 6) or were part of the sham-operated control group (n = 6) and urine samples (n = 18) were collected at 570 minutes post-intervention. Two alternative applications of cfDNA measurement were tested, an indirect method comprising a centrifugation step together with DNA extraction with magnetic beads versus a direct assessment based on two centrifugation steps. CfDNA concentrations were determined by a fluorescent assay using PicoGreen and by qRT-PCR. Genomic (gDNA) and mitochondrial DNA (mtDNA) cfDNA were determined in parallel, taking into account potential differences in the rates of damages caused by oxidative stress. In contrast to previous publications, our results indicate that the direct method is insufficient. Application of the indirect method obtained with the fluorescence assay revealed mean cfDNA levels (SD) of 1.23 (1.76) ng/ml for the hypoxia samples, 4.47 (6.15) ng/ml for the samples exposed to hypoxia + hypothermia and 2.75 (3.62) ng/ml for the control animals. The mean cfDNA levels in piglets exposed to hypoxia + hypothermia revealed significantly higher cfDNA amounts compared to mean cfDNA levels in the samples purely exposed to hypoxia (p < 0.05); however, no significant difference could be determined when compared to the control group (p = 0.09). Application of the indirect method by qRT-PCR revealed mean cfDNA levels of mtDNA and gDNA at the detection limit of the technique and thus no reliable statistics could be performed between the observed cfDNA levels in the investigated groups. The methodology for detection and monitoring of cfDNA in urine has to be further optimized before it can be applied in a clinical setting in the future.

Altered plasma-type gelsolin and amyloid-β in neonates with hypoxic-ischaemic encephalopathy under therapeutic hypothermia

Hypoxic-ischemic encephalopathy (HIE) is a severe neonatal complication responsible for ∼23% of all neonatal deaths. Also, 30-70% of these patients will suffer lifetime disabilities, including learning impairment, epilepsy or cerebral palsy. However, biomarkers for HIE screening, or monitoring disease progression are limited. Herein, we sought to evaluate the clinical usefulness of plasma-type gelsolin (pGSN) and amyloid-beta (Aβ) 40 and 42 as prognostic biomarkers for HIE. pGSN has been previously suggested as a feasible marker in other brain injuries and amyloid-beta 40 and 42 are classically assessed in neurodegenerative diseases. However, to our knowledge, they have not been previously assessed in HIE patients. We have analyzed plasma pGSN and Aβ 40 and 42 levels in 55 newborns (16 controls, 16 mild and 23 moderate-severe HIE) at birth, during 72 h of therapeutic hypothermia, a gold-standard treatment for HIE, and 24 h after hypothermia. Aβ levels were lower in HIE patients, and pGSN levels were progressively reduced in mild and moderate-severe HIE patients. The fact that pGSN reductions could predict the severity of HIE and significantly correlated with the time to undergo hypothermia supports the prognostic value of plasmatic pGSN. Further studies are warranted to investigate the role of pGSN in neonatal HIE.

Temporal patterns of circulating cell-free DNA (cfDNA) in a newborn piglet model of perinatal asphyxia

Perinatal asphyxia is a severe medical condition resulting from oxygen deficiency (hypoxia) at the time of birth, causing worldwide approximately 680,000 newborn deaths every year. Better prediction of severity of damages including early biomarkers is highly demanded. Elevated levels of circulating cell-free DNA (cfDNA) in blood have been reported for a range of different diseases and conditions, including cancer and prematurity. The objective of this study was to validate methods for assessing cfDNA in blood and cerebrospinal fluid (CSF) and to explore temporal variations in a piglet model of neonatal hypoxia-reoxygenation. Different cfDNA extraction methods in combination with cfDNA detection systems were tested, including a fluorescent assay using SYBR Gold and a qRT-PCR-based technique. Newborn piglets (n = 55) were exposed to hypoxia-reoxygenation, hypoxia-reoxygenation and hypothermia, or were part of the sham-operated control group. Blood was sampled at baseline and at post-intervention, further at 30, 270, and 570 minutes after the end of hypoxia. Applying the fluorescent method, cfDNA concentration in piglets exposed to hypoxia (n = 32) increased from 36.8±27.6 ng/ml prior to hypoxia to a peak level of 61.5±54.9 ng/ml after the intervention and deceased to 32.3±19.1 ng/ml at 570 minutes of reoxygenation, whereas the group of sham-operated control animals (n = 11) revealed a balanced cfDNA profile. Animals exposed to hypoxia and additionally treated with hypothermia (n = 12) expressed a cfDNA concentration of 54.4±16.9 ng/ml at baseline, 39.2±26.9 ng/ml at the end of hypoxia, and of 41.1±34.2 ng/ml at 570 minutes post-intervention. Concentrations of cfDNA in the CSF of piglets exposed to hypoxia revealed at post-intervention higher levels in comparison to the controls. However, these observations were only tendencies and not significant. In a first methodological proof-of-principle study exploring cfDNA using a piglet model of hypoxia-reoxygenation variations in the temporal patterns suggest that cfDNA might be an early indicator for damages caused by perinatal asphyxia.

Cerebellum Susceptibility to Neonatal Asphyxia: Possible Protective Effects of N-Acetylcysteine Amide

Background

After perinatal asphyxia, the cerebellum presents more damage than previously suggested.

Objectives

To explore if the antioxidant N-acetylcysteine amide (NACA) could reduce cerebellar injury after hypoxia-reoxygenation in a neonatal pig model.

Methods

Twenty-four newborn pigs in two intervention groups were exposed to 8% oxygen and hypercapnia, until base excess fell to -20 mmol/l or the mean arterial blood pressure declined to <20 mmHg. After hypoxia, they received either NACA (NACA group, n = 12) or saline (vehicle-treated group, n = 12). One sham-operated group (n = 5) served as a control and was not subjected to hypoxia. Observation time after the end of hypoxia was 9.5 hours.

Results

The intranuclear proteolytic activity in Purkinje cells of asphyxiated vehicle-treated pigs was significantly higher than that in sham controls (p = 0.03). Treatment with NACA was associated with a trend to decreased intranuclear proteolytic activity (p = 0.08), There were significantly less mutations in the mtDNA of the NACA group compared with the vehicle-treated group, 2.0 × 10^-4 (±2.0 × 10^-4) versus 4.8 × 10^-5(±3.6 × 10^-4, p < 0.05).

Conclusion

We found a trend to lower proteolytic activity in the core of Purkinje cells and significantly reduced mutation rate of mtDNA in the NACA group, which may indicate a positive effect of NACA after neonatal hypoxia. Measuring the proteolytic activity in the nucleus of Purkinje cells could be used to assess the effect of different neuroprotective substances after perinatal asphyxia.

N-Acetylcysteine Amide Exerts Possible Neuroprotective Effects in Newborn Pigs after Perinatal Asphyxia

BACKGROUND

Perinatal asphyxia and ensuing reoxygenation change the antioxidant capacity of cells and organs.

OBJECTIVES

To analyze the neuroprotective effect of the antioxidant N-acetylcysteine amide (NACA) after perinatal hypoxia-reoxygenation with an emphasis on proinflammatory cytokines and the transcription factor NF-κB in the prefrontal cortex of neonatal pigs.

METHODS

Twenty-nine newborn pigs, aged 12-36 h, were subjected to global hypoxia and hypercapnia. One sham-operated group (n = 5) and 2 experimental groups (n = 12) were exposed to 8% oxygen, until the base excess was -20 mmol/l or the mean arterial blood pressure fell to <20 mm Hg (asphyxia with NACA or saline). The pigs were observed for 9.5 h after hypoxia. Samples of prefrontal cortex and plasma were analyzed.

RESULTS

Cortex: there was no significant difference in mRNA expression between the intervention groups regarding IL-1β, IL6, TNFα, MMP2, MMP9 or IL18. Pigs exposed to hypoxia-reoxygenation and treatment with NACA (NACA-pigs) had a significantly lower protein concentration of IL-1β than pigs treated with saline (placebo controls), i.e. 8.8 ± 3.9 versus 16.8 ± 10.5 pg/mg protein (p = 0.02). The activation of the transcription factor NF-κB (measured as the fold-change of phosphorylated p65Ser 536), was reduced in the NACA-pigs when compared to the placebo controls (5.2 ± 4.3 vs. 16.0 ± 13.5; p = 0.02). No difference between the intervention groups regarding brain histopathology or in the levels of 8-oxoguanine measured in the prefrontal cortex were observed. Plasma: the NACA-pigs had a stronger reduction of TNFα in the first 30 min following asphyxia compared with the placebo controls, i.e. 36 (30-44) versus 24 (14-32)% (p = 0.01).

CONCLUSION

The reduced levels of the pivotal inflammatory markers IL-1β and TNFα and the transcription factor NF-κB may indicate that NACA has possible neuroprotective effects after perinatal asphyxia.

Obstructive sleep apnea decreases central nervous system-derived proteins in the cerebrospinal fluid

We hypothesized that one mechanism underlying the association between obstructive sleep apnea (OSA) and Alzheimer's disease is OSA leading to decreased slow wave activity (SWA), increased synaptic activity, decreased glymphatic clearance, and increased amyloid-β. Polysomnography and lumbar puncture were performed in OSA and control groups. SWA negatively correlated with cerebrospinal fluid (CSF) amyloid-β-40 among controls and was decreased in the OSA group. Unexpectedly, amyloid-β-40 was decreased in the OSA group. Other neuronally derived proteins, but not total protein, were also decreased in the OSA group, suggesting that OSA may affect the interaction between interstitial and cerebrospinal fluid. Ann Neurol 2016;80:154-159.