超出生体重児に対する早期デキサメサゾン投与の有用性 : National Institute of Child Health and Human Development Neonatal research Network報告 (海外誌掲載論文の和文概要とそれに対するコメント)

There is now an abundance of evidence to show that short-chain fatty acids (SCFAs) play an important role in the maintenance of health and the development of disease. SCFAs are a subset of fatty acids that are produced by the gut microbiota during the fermentation of partially and nondigestible polysaccharides. The highest levels of SCFAs are found in the proximal colon, where they are used locally by enterocytes or transported across the gut epithelium into the bloodstream. Two major SCFA signaling mechanisms have been identified, inhibition of histone deacetylases (HDACs) and activation of G-protein-coupled receptors (GPCRs). Since HDACs regulate gene expression, inhibition of HDACs has a vast array of downstream consequences. Our understanding of SCFA-mediated inhibition of HDACs is still in its infancy. GPCRs, particularly GPR43, GPR41, and GPR109A, have been identified as receptors for SCFAs. Studies have implicated a major role for these GPCRs in the regulation of metabolism, inflammation, and disease. SCFAs have been shown to alter chemotaxis and phagocytosis; induce reactive oxygen species (ROS); change cell proliferation and function; have anti-inflammatory, antitumorigenic, and antimicrobial effects; and alter gut integrity. These findings highlight the role of SCFAs as a major player in maintenance of gut and immune homeostasis. Given the vast effects of SCFAs, and that their levels are regulated by diet, they provide a new basis to explain the increased prevalence of inflammatory disease in Westernized countries, as highlighted in this chapter.

The role of short-chain fatty acids in health and disease.

Eukaryotic genomes are packaged into nucleosome particles that occlude the DNA from interacting with most DNA binding proteins. Nucleosomes have higher affinity for particular DNA sequences, reflecting the ability of the sequence to bend sharply, as required by the nucleosome structure. However, it is not known whether these sequence preferences have a significant influence on nucleosome position in vivo, and thus regulate the access of other proteins to DNA. Here we isolated nucleosome-bound sequences at high resolution from yeast and used these sequences in a new computational approach to construct and validate experimentally a nucleosome–DNA interaction model, and to predict the genome-wide organization of nucleosomes. Our results demonstrate that genomes encode an intrinsic nucleosome organization and that this intrinsic organization can explain ∼50% of the in vivo nucleosome positions. This nucleosome positioning code may facilitate specific chromosome functions including transcription factor binding, transcription initiation, and even remodelling of the nucleosomes themselves.

http://absimage.aps.org/image/MAR08/MWS_MAR08-2008-020581.pdf

The Genomic Code for Nucleosome Positioning

Serotonin, tryptophan metabolism and the brain-gut-microbiome axis.

https://www.cell.com/trends/molecular-medicine/pdf/S1471-4914(14)00081-1.pdf

Microbiota and neurodevelopmental windows: implications for brain disorders

Importance Hypoxic-ischemic encephalopathy (HIE) occurs in 1 to 8 per 1000 live births in developed countries. Historically, the clinician has had little to offer neonates with HIE other than systemic supportive care. Recently, the neuroprotective therapy of hypothermia has emerged as the standard of care, and other complementary therapies are rapidly transitioning from the basic science to clinical care. Objective To examine the pathophysiology of HIE and the state of the art for the clinical care of neonates with HIE. Evidence Review We performed a literature review using the PubMed database. Results focused on reviews and articles published from January 1, 2004, through December 31, 2014. Articles published earlier than 2004 were included when appropriate for historical perspective. Our review emphasized evidence-based management practices for the clinician. Findings A total of 102 articles for critical review were selected based on their relevance to the incidence of HIE, pathophysiology, neuroimaging, placental pathology, biomarkers, current systemic supportive care, hypothermia, and emerging therapies for HIE and were reviewed by both of us. Seventy-five publications were selected for inclusion in this article based on their relevance to these topics. The publications highlight the emergence of serum-based biomarkers, placental pathology, and magnetic resonance imaging as useful tools to predict long-term outcomes. Hypothermia and systemic supportive care form the cornerstone of therapy for HIE. Conclusions and Relevance The pathophysiology of HIE is now better understood, and treatment with hypothermia has become the foundation of therapy. Several neuroprotective agents offer promise when combined with hypothermia and are entering clinical trials.

https://jamanetwork.com/journals/PEDS/articlepdf/2118582/prv140005supp1_prod.pdf

Hypoxic-ischemic encephalopathy: a review for the clinician.

The mammalian gastrointestinal tract harbors a highly diverse microbial population that plays a major role in nutrition, metabolism, protection against pathogens, and development of the immune system It is estimated that at least 1000 different bacterial species cohabit the human intestinal tract Most recently, the Human Microbiome Project, using new genomic technologies, has started a catalog of specific microbiome composition and its correlation with health and specific diseases Herein we provide a brief review of the intestinal microbiome, with a focus on new studies showing that there is an important link between the microbes that inhabit the intestinal tract and the developing brain With future research, an understanding of this link may help us to treat various neurobehavioral problems such as autism, schizophrenia, and anxiety

https://jamanetwork.com/journals/jamapediatrics/articlepdf/1569276/pra120009_374_379.pdf

Effect of intestinal microbial ecology on the developing brain.

Lactobacillus rhamnosus GG (LGG), a probiotics, ameliorates intestinal and other organ inflammation in infant rats. The hypothesis is that live and heat-killed LGG have similar effects on decreasing the inflammatory response induced by E. coli lipopolysaccharide (LPS) in the infant rat. Using a gastrostomy-fed rat model, 7-d-old rat pups were gastrostomy fed with or without live LGG (10(8) or 10(12) cfu x L(-1) x kg(-1) x d(-1)) for 6 d. In a separate experiment, LPS was administered to rat pups with or without live or heat-killed LGG (10(8) cfu x L(-1) x kg(-1) x d(-1)). Cytokine/chemokine proteins were determined by ELISA or multiplex assay. Both live and heat-killed LGG decreased LPS-induced cytokine-induced neutrophil chemoattractant-1 (CINC-1) production in liver and plasma (p < 0.05) and also showed a trend (p = 0.09) in lungs. Live and heat-killed LGG ameliorated LPS-suppressed IL-10 level in lungs (p < 0.05). Both forms of LGG decreased IL-1b production in liver. There was no difference between low and high doses of live LGG in the production of CINC-1, TNF-alpha, and myeloperoxidase (MPO). There was a trend of increase of claudin-1 in both live and heat-killed groups (p = 0.08). In conclusion, both live and heat-killed LGG provided by the enteral route decrease LPS-induced proinflammatory mediators and increase anti-inflammatory mediators.

/pdf/live-and-heat-killed-lactobacillus-rhamnosus-gg-effects-on-j7pr2i5yj7.pdf

Live and heat-killed Lactobacillus rhamnosus GG: effects on proinflammatory and anti-inflammatory cytokines/chemokines in gastrostomy-fed infant rats.

As neonatal intensive care has evolved, the focus has shifted from improving mortality alone to an effort to improve both mortality and morbidity. The most frequent source of neonatal brain injury occurs as a result of hypoxic-ischemic injury. Hypoxic-ischemic injury occurs in about 2 of 1,000 full-term infants and severe injured infants will have lifetime disabilities and neurodevelopmental delays. Most recently, remarkable efforts toward neuroprotection have been started with the advent of therapeutic hypothermia and a key step in the evolution of neonatal neuroprotection is the discovery of biomarkers that enable the clinician-scientist to screen infants for brain injury, monitor progression of disease, identify injured brain regions, and assess efficacy of neuroprotective clinical trials. Lastly, biomarkers offer great hope identifying when an injury occurred shedding light on the potential pathophysiology and the most effective therapy. In this article, we will review biomarkers of HIE including S100B, neuron specific enolase, umbilical cord IL-6, CK-BB, GFAP, myelin basic protein, UCHL-1, and pNF-H. We hope to contribute to the awareness, validation, and clinical use of established as well as novel neonatal brain injury biomarkers.

/pdf/biomarkers-of-hypoxic-ischemic-encephalopathy-in-newborns-2n5dwp80wt.pdf

Biomarkers of hypoxic-ischemic encephalopathy in newborns

Severe hypoxic-ischemic encephalopathy (HIE) is a devastating condition that can lead to mortality and long-term disabilities in term newborns. No rapid and reliable laboratory test exists to assess the degree of neuronal injury in these patients. We propose two possible biomarkers: 1) phosphorylated axonal neurofilament heavy chain (pNF-H) protein, one of the major subunits of neurofilaments, found only in axonal cytoskeleton of neurons and 2) Ubiquitin C-terminal hydrolase 1 (UCHL1 protein) that is heavily and specifically concentrated in neuronal perikarya and dendrites. High-serum pNF-H and UCHL1 levels are reported in subarachnoid hemorrhage and traumatic brain injury, suggesting that they are released into blood following neuronal injury. We hypothesized that serum pNF-H and UCHL1 were higher in neonates with moderate-to-severe HIE than in healthy neonates. A time-limited enrollment of 14 consecutive patients with HIE and 14 healthy controls was performed. UCHL1 and pNF-H were correlated with clinical data and brain MRI. UCHL1 and pNF-H serum levels were higher in HIE versus controls. UCHL1 showed correlation with the 10-min Apgar score, and pNF-H showed correlation with abnormal brain MRI. Our findings suggest that serum UCHL1 and pNF-H could be explored as diagnostic and prognostic tools in neonatal HIE.

/pdf/a-pilot-study-of-novel-biomarkers-in-neonates-with-hypoxic-42e2tmow4b.pdf

Martha Douglas-Escobar

Papers

Hypoxic-ischemic encephalopathy: a review for the clinician.

Effect of intestinal microbial ecology on the developing brain.

Live and heat-killed Lactobacillus rhamnosus GG: effects on proinflammatory and anti-inflammatory cytokines/chemokines in gastrostomy-fed infant rats.

Biomarkers of hypoxic-ischemic encephalopathy in newborns

A Pilot Study of Novel Biomarkers in Neonates With Hypoxic-Ischemic Encephalopathy