Association of sickle cell trait with adverse pregnancy outcomes in a population-based cohort.

INTRODUCTION: Sickle cell trait (SCT) is common in African descendants. Its association with several adverse pregnancy outcomes (APOs) has been reported but remains inconsistent. The objectives of this study are to test associations of SCT with APOs in non-Hispanic Black women, including (1) validate the associations of SCT with previously reported APOs, (2) test novel associations of SCT with broad spectrum of APOs, and (3) estimate the attributable risk of SCT for implicated APOs. MATERIAL AND METHODS: This is a retrospective analysis of a prospectively designed population-based cohort. Women/participants were self-reported non-Hispanic Black women from the UK Biobank (UKB). SCT status was determined based on heterozygous Glu6Val in the HBB gene. Several APOs were studied, including four previously reported SCT-associated APOs (preeclampsia, bacteriuria, pregnancy loss, and preterm delivery), and broad conditions related to pregnancy, childbirth, and the puerperium. APOs were curated by experts' peer review and consensus processes. Associations of SCT with APOs were tested by estimating its relative risk and 95% confidence interval (95% CI), adjusting for number of live births and age at first birth. Attributable risk proportion (ARP) and population attributable risk proportion (PARP) of SCT to APOs were estimated. RESULTS: Among the 4057 self-reported non-Hispanic Black women with pregnancy records in the UKB, 581 (14.32%) were SCT carriers. For four previously reported SCT-associated APOs, two were confirmed at a nominal P < 0.05; relative risk (RR) was 2.39 (95% CI 1.09-5.23) for preeclampsia, and 4.85 (95% CI 1.77-13.27) for bacteriuria. SCT contributed substantially to these two APOs among SCT carriers, with attributable risk proportion estimated at 61.00% and 68.96% for preeclampsia and bacteriuria, respectively. SCT also contributed substantially to these two APOs in the population (self-reported Black UK women), with population attributable risk proportion estimated at 18.30% and 24.14% for preeclampsia and bacteriuria, respectively. In addition, novel associations were found for seven other APOs (nominal P < 0.05). CONCLUSIONS: SCT is significantly associated with APOs in this study and contributes substantially to APOs among self-reported Black women in the UK. Confirmation of these findings in independent study populations is required.

Defining necrotizing enterocolitis: current difficulties and future opportunities.

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in hospitalized infants. First classified through Bell staging in 1978, a number of additional definitions of NEC have been proposed in the subsequent decades. In this review, we summarize eight current definitions of NEC, and explore similarities and differences in clinical signs and radiographic features included within these definitions, as well as their limitations. We highlight the importance of a global consensus on defining NEC to improve NEC research and outcomes, incorporating input from participants at an international NEC conference. We also highlight the important role of patient-families in helping to redefine NEC.

Grading the evidence to identify strategies to modify risk for necrotizing enterocolitis.

Although risk for necrotizing enterocolitis (NEC) is often presented from the perspective of a premature infant's vulnerability to nonmodifiable risk factors, in this paper we describe the evidence and present recommendations to manage modifiable risks that are amenable to clinical actions. Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria, we present recommendations in the context of their supporting evidence in a way that balances risks (e.g. potential harm, cost) and benefits. Across the prenatal, intrapartum, early and late clinical course, strategies to limit NEC risk in premature infants are presented. Our goal is to summarize modifiable NEC risk factors, grade the evidence to offer quality improvement (QI) targets for healthcare teams and offer a patient-family advocate's perspective on how to engage parents to recognize and reduce NEC risk.

Linking fat intake, the intestinal microbiome, and necrotizing enterocolitis in premature infants.

Components of diet, including the total amounts and specific types of fat, affect the composition of the intestinal microbiome in both animal models and cohort studies of humans. Amounts of total fat and specific fatty acids (FA) are some of the most variable nutritional components of breast milk. Evaluations of the microbiome in premature infants have shown decreased diversity of species and increased proportions of potentially pathogenic bacteria. Microbial patterns in premature infants may be affected by nutritional fat intake, altering risk of diseases such as necrotizing enterocolitis. Dietary FA may also impact disease susceptibility through molecular mechanisms. Specifically, intestinal Toll-like receptor 4 expression is altered by manipulation of FA in murine models. Abnormal increased expression of Toll-like receptor 4, the receptor for lipopolysaccharide, has been implicated in necrotizing enterocolitis. This report will review the role of dietary fat in the composition of the intestinal microbiome, the extreme variability of FA intake in premature infants, and associations of both dysbiosis and FA intake with the development of necrotizing enterocolitis.

Oropharyngeal administration of mother's milk to prevent necrotizing enterocolitis in extremely low-birth-weight infants: theoretical perspectives.

The oropharyngeal administration of mother's milk-placing drops of milk onto the infant's oral mucosa-may serve as a preventative strategy against necrotizing enterocolitis (NEC) for extremely low-birth-weight (ELBW: birth weight <1000 g) infants. Necrotizing enterocolitis is a devastating gastrointestinal disorder which is associated with significant mortality for ELBW infants. Survivors are at risk for costly and handicapping morbidities, including severe neurological impairment. The oropharyngeal administration of mother's milk to ELBW infants may serve to expose the infant's oropharynx to protective (immune and trophic) biofactors (also present in amniotic fluid) and may protect the infant against NEC. Emerging evidence suggests that this intervention may have many benefits for extremely premature infants including protection against bacteremia, NEC, and ventilator-associated pneumonia, an earlier attainment of full enteral feeds, enhanced maturation of oral feeding skills, improved growth, and enhanced breast-feeding outcomes. While more research is needed to definitively establish safety and efficacy of this intervention, this article will examine biological plausibility and will describe the theoretical mechanisms of protection against NEC for ELBW infants who receive this intervention. Nurses play a key role in advancing the science and practice of this intervention. Future directions for research and implications for nursing practice will also be presented.

Maternal breast milk transforming growth factor-beta and feeding intolerance in preterm infants.

BACKGROUND: Feeding intolerance (FI) occurs commonly in the neonatal intensive care unit. Breast milk contains a large pool of transforming growth factor-beta (TGF-ß). Few studies describe TGF-ß levels in preterm milk, and the relationship to FI remains unexplored. We measured TGF-ß levels in preterm breast milk to investigate a correlation with FI in preterm infants. METHODS: Prospective observational trial of 100 mother-infant pairs, enrolling infants born below 32 wk gestation and less than 1,500 g, and mothers who planned to provide breast milk. TGF-ß levels were measured using enzyme-linked immunosorbent assay. Infant charts were reviewed for outcomes. RESULTS: TGF-ß declined postnatally, most elevated in colostrum (P < 0.01). TGF-ß2 levels were higher than TGF-ß1 at all time points (P < 0.01). Colostrum TGF-ß levels correlated inversely with birth weight (P < 0.01) and gestational age (P < 0.05). One-week TGF-ß2 levels were reduced in growth-restricted infants with FI (P < 0.01). Of infants with necrotizing enterocolitis (NEC), TGF-ß2 levels appeared to be low, but small sample size precluded meaningful statistical comparisons. CONCLUSION: TGF-ß levels decline temporally in preterm milk. TGF-ß1 colostrum levels correlate inversely with birth weight and gestational age. TGF-ß2 may play a role in FI in growth-restricted infants. The relationship of TGF-ß2 and NEC merits future investigation.

Murine gut microbiota and transcriptome are diet dependent.

OBJECTIVE: Here, we determine how formula feeding impacts the gut microbiota and host transcriptome. BACKGROUND: Formula-fed (FF) infants are at risk for diseases that involve complex interactions between microbes and host immune elements such as necrotizing enterocolitis. The aims of this study were to simultaneously examine the microbiota and host transcriptional profiles of FF and maternal-fed (MF) mice to evaluate how diet impacts gut colonization and host genes. METHODS: After 72 hours of FF or MF, colonic tissue was collected. 16S ribosomal RNA was sequenced with Roche GS-FLX (Genome Sequencer-FLX) pyrosequencing. Operational taxonomical unit clustering, diversity analysis, and principal coordinate analysis (PCA) were performed. Complementary DNA libraries were sequenced by Solexa. Reads were annotated by BLAST (Basic Local Alignment Search Tool) search against mouse RNA database [National Center for Biotechnology Information (NCBI) build-37] and functionally classified using the KOG (Eukaryotic Orthologous Groups) database (NCBI). RESULTS: Firmicutes (P < 0.001) was the dominant phylum in MF pups, whereas Proteobacteria (P < 0.001) and Bacteroidetes (P < 0.05) were dominant in FF mice. On the genus level, FF mice had increased Serratia (P < 0.001) and Lactococcus (P < 0.05) whereas MF mice had increased Lactobacillus (P < 0.001). PCA confirmed clustering by diet. Solexa sequencing demonstrated different (P < 0.05) messenger RNA transcript levels in 148 genes. Heme oxygenase 1 (P < 0.01), an oxidative stress marker, was increased 25-fold in FF mice. In addition, decreased vinculin (P < 0.05), a cytoskeletal protein associated with adherens junctions in FF pups suggested impaired gut structural integrity. Diet also impacted immune regulation, cell cycle control/gene expression, cell motility, and vascular function genes. CONCLUSIONS: FF shifted gut microbiota and structural integrity, oxidative stress, and immune function genes, presumably increasing vulnerability to disease in FF mice. Interrogation of microbial and host gene expression in FF neonates may offer new insight on how diet affects disease pathogenesis.

Microbiota from Preterm Infants Who Develop Necrotizing Enterocolitis Drives the Neurodevelopment Impairment in a Humanized Mouse Model.

Necrotizing enterocolitis (NEC) is the leading basis for gastrointestinal morbidity and poses a significant risk for neurodevelopmental impairment (NDI) in preterm infants. Aberrant bacterial colonization preceding NEC contributes to the pathogenesis of NEC, and we have demonstrated that immature microbiota in preterm infants negatively impacts neurodevelopment and neurological outcomes. In this study, we tested the hypothesis that microbial communities before the onset of NEC drive NDI. Using our humanized gnotobiotic model in which human infant microbial samples were gavaged to pregnant germ-free C57BL/6J dams, we compared the effects of the microbiota from preterm infants who went on to develop NEC (MNEC) to the microbiota from healthy term infants (MTERM) on brain development and neurological outcomes in offspring mice. Immunohistochemical studies demonstrated that MNEC mice had significantly decreased occludin and ZO-1 expression compared to MTERM mice and increased ileal inflammation marked by the increased nuclear phospho-p65 of NFκB expression, revealing that microbial communities from patients who developed NEC had a negative effect on ileal barrier development and homeostasis. In open field and elevated plus maze tests, MNEC mice had worse mobility and were more anxious than MTERM mice. In cued fear conditioning tests, MNEC mice had worse contextual memory than MTERM mice. MRI revealed that MNEC mice had decreased myelination in major white and grey matter structures and lower fractional anisotropy values in white matter areas, demonstrating delayed brain maturation and organization. MNEC also altered the metabolic profiles, especially carnitine, phosphocholine, and bile acid analogs in the brain. Our data demonstrated numerous significant differences in gut maturity, brain metabolic profiles, brain maturation and organization, and behaviors between MTERM and MNEC mice. Our study suggests that the microbiome before the onset of NEC has negative impacts on brain development and neurological outcomes and can be a prospective target to improve long-term developmental outcomes.

A randomized controlled trial of oropharyngeal therapy with mother's own milk for premature infants.

OBJECTIVE: To determine if oropharyngeal therapy with mother's own milk (OPT-MOM) reduces late-onset sepsis (L-OS; primary outcome), NEC, death, length of stay, time to full enteral nutrition (FEN) and full oral feeds in preterm infants (BW < 1250 g). DESIGN: Infants (N = 220) were randomized to Group A (milk) or B (placebo) and received 0.2 mL every 2 h for 48 h, then every 3 h until 32 weeks CGA. RESULTS: There were no significant differences in L-OS, NEC or death. Group A trended towards an 8-day reduction in stay, 8-day reduction in time to FEN and a 6-day reduction in time to full oral feeds, compared to B. While clinically relevant, due to large variability in outcomes and lack of power, p values were > 0.05. CONCLUSION: OPT-MOM did not reduce L-OS, NEC or death. Group A trended towards a reduced stay and better nutritional outcomes, but results were not statistically significant. CLINICALTRIALS: GOV: NCT02116699.

Sickle Cell Trait and Risk for Common Diseases: Evidence from the UK Biobank.

BACKGROUND: Sickle cell trait is typically considered benign. Although evidence remains inconsistent, recent studies suggest that it is associated with several common diseases. We systematically assessed associations of sickle cell trait with reported diseases in a large population-based cohort. METHODS: Study subjects were self-reported Blacks from the UK Biobank (UKB), a United Kingdom population-based cohort of subjects aged 40-69 years at recruitment in the United Kingdom. Sickle cell status was based on the International Classification of Diseases, Tenth Revision (ICD-10) or mutations in the HBB gene. Diagnoses of diseases were obtained from ICD-10 and self-reports. Associations of sickle cell trait and diseases were tested using logistic regression, adjusting for age at recruitment, sex, and genetic background (top 10 principal components). RESULTS: Among the 8019 Blacks in the UKB, 699 (8.72%) were sickle cell trait carriers; the rate was significantly higher in females (9.74%) than males (7.48%), P = .0005. Sickle cell trait was under-diagnosed; most heterozygous hemoglobin subunit beta (HBB) gene Glu6Val carriers did not have a sickle cell trait ICD-10 record. Compared with non-sickle cell trait, sickle cell trait carriers had significantly increased risk for type 2 diabetes; odds ratio 1.38; 95% confidence interval, 1.12-1.68; P = .002. Sickle cell trait was also significantly associated with increased risk for renal diseases (rhabdomyolysis, end-stage renal disease, chronic kidney disease, renal papillary necrosis) and vascular diseases (hypertension, retinopathy, non-ischemic stroke), P < .05. While most of these diseases are complications/comorbidities of diabetes, their associations with sickle cell trait remained significant after adjusting for diabetes. Association with end-stage renal disease was stronger in subjects without diabetes, odds ratio 6.45; 95% confidence interval, 1.93-19.61; P = .001. CONCLUSIONS: Sickle cell trait is significantly associated with increased risk for diabetes and diabetes-related complications/comorbidities.

Probiotics and prevention of neonatal necrotizing enterocolitis.

PURPOSE OF REVIEW: This review will summarize the clinical trials evaluating the role of prophylactic probiotic supplementation in preterm infants in order to reduce the incidence of necrotizing enterocolitis (NEC). RECENT FINDINGS: Evidence suggests that probiotic supplementation in preterm infants reduces the incidence of NEC. In fact, recent meta-analyses have called for the use of probiotics as preventive therapy in subsets of this population. However, although multiple studies have evaluated the use of probiotics for this indication in preterm infants, these trials have used different formulations of bacteria, at differing doses and using varied protocols for administration; thus many unanswered questions remain. In addition, theoretical safety issues and concerns regarding quality of product still need to be addressed. SUMMARY: As NEC remains a serious problem for preterm neonates, proven therapies for prevention and treatment of this dreaded disease are needed. While the evidence does support a future role for probiotics in the prevention of NEC, it is of utmost importance to first ensure that a safe and high-quality product meeting rigorous standards will be provided to these at-risk infants.

Association of Sickle Cell Trait with Risk and Mortality of COVID-19: Results from the United Kingdom Biobank.

Sickle cell trait (SCT) carriers inherit one copy of the Glu6Val mutation in the hemoglobin gene and is particularly common in Black individuals (5-10%). Considering the roles of hemoglobin in immune responses and the higher risk for coronavirus disease (COVID-19) among Black individuals, we tested whether Black SCT carriers were at increased risk for COVID-19 infection and mortality according to the United Kingdom Biobank. Among Black individuals who were tested for COVID-19, we found similar infection rates among SCT carriers (14/72; 19.7%) and noncarriers (167/791; 21.1%), but higher COVID-19 mortality rates among SCT carriers (4/14; 28.6%) than among noncarriers (21/167; 12.6%) (odds ratio [OR], 3.04; 95% confidence interval [CI], 0.69-11.82; P = 0.12). Notably, SCT carriers with preexisting diabetes had significantly higher COVID-19 mortality (4/4; 100%) than those without diabetes (0/10; 0%; (OR, 90.71; 95% CI, 5.66-infinite; P = 0.0005). These findings suggest that Black SCT carriers with preexisting diabetes are at disproportionally higher risk for COVID-19 mortality. Confirmation by larger studies is warranted.

Can Fish Oil Reduce the Incidence of Necrotizing Enterocolitis by Altering the Inflammatory Response?

Necrotizing enterocolitis (NEC) is a devastating bowel necrosis that predominantly affects preterm infants and is characterized by an imbalance toward a proinflammatory state. Fish oil or omega-3 long-chain polyunsaturated fatty acids have the potential to modulate inflammation. In this article, the authors examine the evidence in support of fish oil supplementation to alter the inflammatory response and potentially reduce the risk of NEC.

Oropharyngeal Mother's Milk: State of the Science and Influence on Necrotizing Enterocolitis.

Oropharyngeal administration of mother's own milk-placing drops of milk directly onto the neonate's oral mucosa-may serve to (ex utero) mimic the protective effects of amniotic fluid for the extremely low birth weight infant; providing protection against necrotizing enterocolitis. This article presents current evidence to support biological plausibility for the use of OroPharyngeal Therapy with Mother's Own Milk (OPT-MOM) as an immunomodulatory therapy; an adjunct to enteral feeds of mother's milk administered via a nasogastric or orogastric tube. Current methods and techniques are reviewed, published evidence to guide clinical practice will be presented, and controversies in practice will be addressed.

The importance of pro-inflammatory signaling in neonatal necrotizing enterocolitis.

Despite modern medical advances, necrotizing enterocolitis (NEC) remains a significant cause of morbidity and mortality in neonatal intensive care units, affecting 10% of premature neonates born weighing less than 1500 g. Although many advances have been made in the understanding of NEC, the etiology and pathophysiology remain incompletely understood, and treatment is limited to supportive care. In recent years, many studies have evaluated the inflammatory cascade that is central to the disease process, and research is ongoing into strategies to prevent and/or ameliorate neonatal NEC. In this review, we examine the key points in the signaling pathways involved in NEC, and potential strategies for prevention and treatment of this dreaded disease.

Necrotizing: A historical perspective.

Necrotizing enterocolitis is a devastating disease afflicting premature infants, though after 50 years of investigation, the pathophysiology remains elusive. This report describes the possible etiologic factors from a historical perspective, and outlines the importance of human milk, intestinal blood flow, and intestinal blood flow changes from a developmental perspective over the last 40-50 years.

New Medical and Surgical Insights Into Neonatal Necrotizing Enterocolitis: A Review.

Importance: Necrotizing enterocolitis (NEC) has long remained a significant cause of morbidity and mortality in neonatal intensive care units. While the mainstay of treatment for this devastating condition remains largely supportive, research efforts continue to be directed toward understanding pathophysiology as well as how best to approach surgical management when indicated. Observations: In this review, we first examine recent medical observations, including overviews on the microbiome and a brief review of the use of probiotics. Next, we discuss the use of biomarkers and how clinicians may be able to use them in the future to predict the course of disease and, perhaps, the need for surgical intervention. We then provide an overview on the use of exclusive human milk feeding and the utility of this approach in preventing NEC. Finally, we discuss recent developments in the surgical management of NEC, beginning with indications for surgery and following with a section on technical surgical considerations, including peritoneal drain vs laparotomy. The review concludes with outcomes from infants with surgically treated NEC. Conclusions and Relevance: Although medical treatment options for NEC are largely unchanged, understanding of the disease continues to evolve. As new research methods are developed, NEC pathophysiology can be more completely understood. In time, it is hoped that data from ongoing and planned clinical trials will allow us to routinely add targeted preventive measures in addition to human milk, such as prebiotics and probiotics, to the management of high-risk infants. In addition, the discovery of novel biomarkers may not only prove useful in predicting severity of illness but also will hopefully allow for identification of the disease prior to onset of clinical signs. Finally, continued investigation into optimizing surgical outcomes is essential in this population of infants, many of whom require long-term parenteral therapy and intestinal rehabilitation.

The role of PAF, TLR, and the inflammatory response in neonatal necrotizing enterocolitis.

The pathogenesis of neonatal necrotizing enterocolitis remains poorly understood. Recent evidence suggests that PAF (platelet activating factor) and human toll-like receptors (TLRs) contribute to the pro-inflammatory response that is characteristic of NEC pathology. Understanding the regulation of these molecular interactions may provide new approaches for prevention or treatment of this dreaded condition.