Safety and Effectiveness of Probiotics in Preterm Infants with Necrotizing Enterocolitis

Although necrotizing enterocolitis is a leading cause of morbidity and mortality among preterm infants, its underlying pathophysiology is not fully understood. Gut dysbiosis, an imbalance between commensal and pathogenic microbes, in the preterm infant is likely a major contributor to the development of necrotizing enterocolitis. In this review, we will discuss the increasing use of probiotics in the NICU, an intervention aimed to mitigate alterations in the gut microbiome. We will review the existing evidence regarding the safety and effectiveness of probiotics, and their potential to reduce rates of necrotizing enterocolitis in preterm infants.

Safety and Effectiveness of Probiotics in Preterm Infants with Necrotizing Enterocolitis

Although necrotizing enterocolitis is a leading cause of morbidity and mortality among preterm infants, its underlying pathophysiology is not fully understood. Gut dysbiosis, an imbalance between commensal and pathogenic microbes, in the preterm infant is likely a major contributor to the development of necrotizing enterocolitis. In this review, we will discuss the increasing use of probiotics in the NICU, an intervention aimed to mitigate alterations in the gut microbiome. We will review the existing evidence regarding the safety and effectiveness of probiotics, and their potential to reduce rates of necrotizing enterocolitis in preterm infants.

Outcomes of Moderately Preterm Infants of Insulin-Dependent Diabetic Mothers

OBJECTIVE

 Little is known about the hospital outcomes of moderately preterm (MPT; 29 0/7-33 6/7 weeks gestational age) infants born to insulin-dependent diabetic mothers (IDDMs). We evaluated characteristics and outcomes of MPT infants born to IDDMs compared with those without IDDM (non-IDDM).

STUDY DESIGN

 Cohort study of infants from 18 centers included in the MPT infant database from 2012 to 2013. We compared characteristics and outcomes of infants born to IDDMs and non-IDDMs.

RESULTS

 Of 7,036 infants, 527 (7.5%) were born to IDDMs. Infants of IDDMs were larger at birth, more often received continuous positive pressure ventilation in the delivery room, and had higher risk of patent ductus arteriosus (adjusted relative risk or aRR: 1.49, 95% confidence interval [CI]: 1.20-1.85) and continued hospitalization at 40 weeks postmenstrual age (aRR: 1.55, 95% CI: 1.18-2.05).

CONCLUSION

 MPT infants of IDDM received more respiratory support and prolonged hospitalizations, providing further evidence of the important neonatal health consequences of maternal diabetes.

KEY POINTS

· Little data are available on moderate preterm infants of IDDMs.. · MPT infants of IDDMs need more respiratory support.. · Longer neonatal intensive care unit stays among MPT infants of IDDMs..

Influence of Early Lactation Assistance on Inpatient Exclusive Breastfeeding Rates

BACKGROUND

Human milk feeding reduces the incidence and costs of several maternal and childhood illnesses. Initiation and success of human milk feeding are influenced by race, socioeconomic status, and family support. The influence of early in-hospital lactation assistance in breastfeeding success has been not well described.

RESEARCH AIMS

We aimed to determine how suspected known factors influencing breastfeeding success influence in-hospital human milk feeding rates. Second, we aimed to examine how timing of lactation assistance is related to success of human milk feeding during the newborn hospitalization for healthy infants.

METHODS

We conducted a retrospective cohort study of term infants born between January 1, 2014 and December 31, 2016 at a large tertiary academic hospital. We considered "success" to be 100% human milk feeding during the birth hospitalization, and compared differences in success by demographics, payor, race, and initial feeding preference. Influences of lactation assistance on success were analyzed using multivariable logistic regression.

RESULTS

Mean success with exclusive human milk feeding among 7,370 infants was 48.9%, (n = 3,601). Successful participants were more likely to be 39-40 weeks' gestation (64.9%, n = 2,340), non-Hispanic/non-Latino (80.0%, n = 2,882), and using private insurance (69.2%, n = 2,491). Participants who had early feeding assisted by an International Board Certified Lactation Consultant (IBCLC) before being fed any formula were more likely to be successful than participants who had a feeding assisted by a non-IBCLC nurse (80% vs. 40% respectively).

CONCLUSIONS

Success for exclusive human milk feeding during newborn hospitalization is strongly associated with several factors. Early intervention with IBCLCs can greatly improve breastfeeding success.

Exchange transfusion safety and outcomes in neonatal hyperbilirubinemia

OBJECTIVE

To characterize the prevalence of exchange transfusion (ET), clinical characteristics of infants receiving ET, and ET-associated morbidity and mortality.

STUDY DESIGN

We conducted a multicenter cohort study of infants ≥23 weeks of gestational age (GA) with hyperbilirubinemia who underwent ET within 30 days of birth from 1997 to 2016. We examined clinical characteristics and adverse events after ET. We used multivariable logistic regression to examine the association between clinical risk factors and death.

RESULT

A total of 1252 infants were included; 4% died within 7 days of ET and 6% died before discharge. Compared with infants ≥37 weeks of GA, infants ≤29 weeks of GA had greater odds of death (adjusted odds ratio [95% confidence interval] = 20.08 [7.32, 55.07]).

CONCLUSIONS

Infants ≤ 29 weeks of GA had greater odds of death following ET compared with term infants. These data will support clinicians in evaluating risks and prognosis for infants who require ET.

Probiotic Use and Safety in the Neonatal Intensive Care Unit: A Matched Cohort Study

OBJECTIVE

To determine the prevalence of probiotic administration in infants born preterm over time, as well as the association between probiotic administration and select adverse outcomes.

STUDY DESIGN

We performed a multicenter cohort study of infants 23-29 weeks of gestational age admitted to 289 neonatal intensive care units from 1997 to 2016. We evaluated the type of probiotics given and prevalence of exposure to probiotics over time and by site. We matched infants exposed to probiotics by several factors to unexposed infants receiving enteral feeds on the same postnatal day. We performed conditional logistic regression to evaluate the association between probiotics exposure and adverse outcomes, including necrotizing enterocolitis (NEC), bloodstream infections, meningitis, and death.

RESULTS

Of 78 076 infants, 3626 (4.6%) received probiotics. Probiotic use increased over the study period and varied among neonatal intensive care units. We matched 2178 infants exposed to probiotics to 33 807 without exposure. Probiotic administration was associated with a decrease in NEC (OR 0.62, 95% CI 0.48-0.80) and death (OR 0.52, 95% CI 0.39-0.70), an increase in Candida infection (OR 2.23, 95% CI 1.29-3.85), but no increase in bloodstream infection (OR 0.86, 95% CI 0.70-1.05) or meningitis (OR 1.18, 95% CI 0.40-3.46).

CONCLUSIONS

Probiotic use increased over time and was associated with decreased odds of NEC and death. Prospective, randomized-controlled studies of specific probiotic products are needed to further investigate the safety and efficacy of probiotics in preterm infants.

Impact of procedural multimedia instructions for pH BRAVO testing on patient comprehension: a prospective randomized study

The positive impact on patient comprehension and improved procedural outcomes when multimedia is utilized to convey instructions preprocedurally has been previously shown for gastrointestinal procedures such as colonoscopy. However, in gastroesophageal reflux testing (GERD), we continue to utilize verbal and written instructions to establish this diagnosis when we use BRAVO pH testing. This is arguably a more complex procedure involving stopping medications, placement of a device, and maintaining an accurate diary for the duration of the testing. We hypothesize that by utilizing multimedia to relay complex textual information, patients will have improved comprehension of periprocedural instructions thereby improving data entry and satisfaction of expectations during the procedure. Prospective randomized study of 120 patients undergoing endoscopic placement of the BRAVO pH monitoring capsule for evaluation of GERD receive either written preoperative instructions (control) or written plus video instructions (video group). A composite comprehension score was calculated using procedure-specific parameters of data entry over the 48-hour monitoring period. Patient satisfaction was evaluated on the basis of a five-point Likert scale. Extent of patient satisfaction was defined by the fulfillment of patient expectations. Exclusion criteria included patients who did not have access to the video or did not complete follow-up. Seventy-eight patients completed all follow-up evaluations. The video group (n = 44) had a significantly higher mean comprehension score when compared to the control group (n = 34) (9.6 ± 1.4 vs. 7.4 ± 2.0, P = 0.01). Overall satisfaction with instructions was significantly higher in the intervention group (91% vs. 47%, p 0.01). We detected no significant difference in comprehension or satisfaction scores in subgroup analyses of the video group comparing patients <65 and ≥65 years of age and by education level. Compared to standard written instructions, video instructions improved patient comprehension based on data evaluation, and satisfaction. Therefore, clinicians should consider incorporation of multimedia instructions to enhance patient periprocedural expectations and understanding of reflux pH testing using the BRAVO procedure.

Evaluation of Gentamicin Exposure in the Neonatal Intensive Care Unit and Hearing Function at Discharge

OBJECTIVE

To characterize the association between gentamicin dosing, duration of treatment, and ototoxicity in hospitalized infants.

STUDY DESIGN

This retrospective cohort study conducted at 330 neonatal intensive care units (2002-2014) included inborn infants exposed to gentamicin with available hearing screen results, and excluded infants with incomplete dosing data and major congenital anomalies. Our primary outcome was the final hearing screen result performed during hospitalization: abnormal (failed or referred for further testing in one or both ears) or normal (bilateral passed). The 4 measures of gentamicin exposure were highest daily dose, average daily dose, cumulative dose, and cumulative duration of exposure. We fitted separate multivariable logistic regression models adjusted for demographics, comorbidities, and other clinical events.

RESULTS

A total of 84 808 infants met inclusion/exclusion criteria; median (25th, 75th percentile) gestational age and birth weight were 35 weeks (33, 38) and 2480 g (1890, 3184), respectively. Failed hearing screens occurred in 3238 (3.8%) infants; failed screens were more likely in infants of lower gestational age and birth weight, who had longer hospital lengths of stay, higher rates of morbidities, and were small for gestational age. Median highest daily dose, average daily dose, and cumulative dose were 4.0 mg/kg/day (3.0, 4.0), 3.8 mg/kg/day (3.0, 4.0), and 12.1 mg/kg (9.1, 20.5), respectively. Median cumulative duration of exposure was 3 days (3, 6). In adjusted analysis, gentamicin dose and duration of therapy were not associated with hearing screen failure.

CONCLUSIONS

Gentamicin dosing and duration of treatment were not associated with increased odds of failed hearing screen at the time of discharge from initial neonatal intensive care unit stay.

Prevalence and safety of diazoxide in the neonatal intensive care unit

OBJECTIVE

Diazoxide is used to treat infants with persistent hypoglycemia, but the prevalence of its use and adverse effects are not well described. We report demographic and clinical characteristics of infants treated with diazoxide in neonatal intensive care units (NICUs).

STUDY DESIGN

Retrospective cohort study of infants 24-41 weeks' gestation admitted to 392 NICUs from 1997-2016, comparing characteristics between hypoglycemic infants exposed/not exposed to diazoxide. For diazoxide courses > 1 day, we report percentages of infants starting diuretics and/or developing new ventilator/oxygen requirement during therapy.

RESULTS

Among 1,249,466 infants, 185,832 had hypoglycemia; 1066/185,832 (0.57%) received diazoxide. Diazoxide use increased over time (P = 0.001). Infants receiving diazoxide varied from 0-14.9% among centers. New diuretic courses were associated with 91/664 (14%), and new oxygen or ventilator requirement during therapy was associated with 64/556 (12%) and 34/647 (5%), respectively.

CONCLUSIONS

Diazoxide use in NICU settings has increased over time. Infants receiving diazoxide commonly received diuretics.

Human pulmonary acinar aplasia: reduction of transforming growth factor-beta ligands and receptors

Pulmonary hypoplasia has been found in the human neonatal autopsy population and has been attributed to an alteration in epithelial-mesenchymal interactions during development of the lung. Pulmonary acinar aplasia is a very rare and severe form of pulmonary hypoplasia. The transforming growth factor-betas (TGF-beta) are multifunctional regulatory peptides that are secreted by a variety of normal and malignant cells and are expressed in developing organs including the lung; their tissue distribution patterns have possible significance for signaling roles in many epithelial-mesenchymal interactions. Here, we report our examination of TGF-beta in the lungs of a term female infant diagnosed with pulmonary acinar aplasia whose autopsy revealed extremely hypoplastic lungs with complete absence of alveolar ducts and alveoli. Immunohistochemical and in situ hybridization analyses were used to localize and measure the proteins and mRNA, respectively, for TGF-beta1, TGF-beta2, TGF-beta3, and TGF-beta type I and type II receptors (TGF-beta RI and RII) in formalin-fixed and paraffin-embedded sections of these hypoplastic lungs and normal lungs. Immunostaining for TGF-beta1, TGF-beta2, and TGF-beta RI and RII was significantly lower in the bronchial epithelium and muscle of the hypoplastic lungs than in normal lungs, whereas no difference was detected in staining for other proteins including Clara cell 10-kD protein, adrenomedullin, hepatocyte growth factor/scatter factor, and hepatocyte growth factor receptor/Met in the hypoplastic and normal lungs or in the liver and kidneys of this infant compared with normal liver and kidney. In addition, in situ hybridization showed that TGF-beta1 and TGF-beta RI transcripts were considerably reduced in the bronchial epithelium of the hypoplastic lung compared with normal lung. These results show that there is a selective reduction of TGF-beta in pulmonary acinar aplasia and suggest that the signaling action of TGF-beta in epithelial-mesenchymal interactions in the lungs of this developmental condition may be compromised.

Analysis of mutations within the cytoplasmic domain of the Moloney murine leukemia virus transmembrane protein

The role of the cytoplasmic tail of the Moloney murine leukemia virus transmembrane protein in the regulation of syncytia was examined. Three mutations within the cytoplasmic tail were studied. Linker-insertion in7705-12a is within the viral-associated cytoplasmic tail, linker-insertion in7748-12a is within the R peptide, and a third mutation expresses TM lacking the R peptide (Env R-). The Env R- construct was nonviable in Rat1 cells, however, rapidly reverted to a form containing the R peptide when passaged in NIH/3T3 cells. in7705-12a was temperature-sensitive in Rat1 cells, as previously characterized, but was viable at either temperature in NIH/3T3 cells. in7748-12a was comparable with wild-type M-MuLV. The ability of the env constructs to form large multinucleated syncytia with NIH/3T3 and XC cells were examined using transient expression assays, eliminating reversion events due to viral passage and reverse transcription. The Env R- constructs formed syncytia with NIH/3T3 cells. in7705-12a displays enhanced proteolytic cleavage of the R peptide. Neither linker-insertion mutation in7705-12a or in7748-12a activated fusion with NIH/3T3, despite the abundance of processed TM with in7705-12a. All three mutants were fusion competent with Rat XC cells, even in the absence of any cleavage of the R peptide. These results provide insights regarding steric and the temporal affects of cleavage of the R peptide and the assembly of a fusion competent oligomer.

Detection of adrenomedullin, a hypotensive peptide, in amniotic fluid and fetal membranes

OBJECTIVE

Our purpose was to determine whether adrenomedullin, a multifunctional regulatory peptide involved in blood flow regulation and growth stimulation and with antimicrobial activity, was a component of amniotic fluid from second-trimester human fetus and to determine the source of this peptide.

STUDY DESIGN

A prospective descriptive study was performed on 134 patients undergoing amniocentesis after genetic counseling, ultrasonography, and informed consent. Adrenomedullin expression was determined by immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction in fetal membranes and with radioimmunoassay in amniotic fluids.

RESULTS

Radioimmunoassay of the 134 amniotic fluid specimens revealed adrenomedullin-like immunoreactivity in all of them, ranging in concentration from 10 to 300 fmol/25 microliters (170 +/- 62 fmol/25 microliters). Immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction further established the expression of adrenomedullin protein and messenger ribonucleic acid in fetal amniotic membranes, suggesting that this organ is the source of amniotic adrenomedullin.

CONCLUSIONS

Our results clearly demonstrate the presence of adrenomedullin in second-trimester human amniotic fluid and adrenomedullin messenger ribonucleic acid and protein in amniotic membranes, suggesting that adrenomedullin is a hormone involved in the maintenance of normal pregnancy. Further studies with these molecular tools are in progress to determine the precise role of this hormone and whether adrenomedullin plays a role in the pathogenesis of various disorders of pregnancy.

Analysis of messenger ribonucleic acid and protein for the ligands and receptors of the platelet-derived growth factor signaling pathway in the placenta, extraembryonic membranes, and uterus during the latter half of murine gestation

Previous investigation of ligand and receptor messenger RNA (mRNA) expression implicated the platelet-derived growth factor (PDGF) pathway as a participant in the maintenance of pregnancy and fetal development during the first half of murine gestation. We extended these studies using Northern and in situ RNA hybridization and immunohistochemical detection of protein to evaluate the expression kinetics and cell-specific localization of PDGF-A, PDGF-B, PDGF alpha-receptor, and PDGF beta-receptor in mouse placenta, extraembryonic membranes, and uterus during the second half of gestation (days 9.5-18.5). Northern blotting experiments reveal that mRNAs for the PDGF signaling components exhibit unique time-dependent and tissue-specific expression in the placenta and uterus, being progressively and coordinately up-regulated as gestation proceeds. Cell-specific localization of mRNA and protein by in situ hybridization and immunohistochemistry demonstrates widespread expression in multiple cell types of the placenta, gravid uterus, and extraembryonic membranes. Abundant PDGF protein and mRNA expression is exhibited in the nucleated fetal erythroid progenitor cells that originate in the extraembryonic membranes and circulate throughout the developing conceptus. Our data together with those of previous studies demonstrate that PDGF ligands and receptors are globally expressed in many cell types within fetal and maternal tissues during murine gestation and, thus, imply a potential role for PDGF in fetal development and maternal-fetal interactions.

Malignant transformation of the human endometrium is associated with overexpression of lactoferrin messenger RNA and protein

In the mouse uterus, lactoferrin is a major estrogen-inducible uterine secretory protein, and its expression correlates directly with the period of peak epithelial cell proliferation. In this study, we examine the expression of lactoferrin mRNA and protein in human endometrium, endometrial hyperplasias, and adenocarcinomas using immunohistochemistry, Western immunoblotting, and Northern and in situ RNA hybridization techniques. Our results reveal that lactoferrin is expressed in normal cycling endometrium by a restricted number of glandular epithelial cells located deep in the zona basalis. Two thirds (8 of 12) of the endometrial adenocarcinomas examined overexpress lactoferrin. This tumor-associated increase in lactoferrin expression includes an elevation in the mRNA and protein of individual cells and an increase in the number of cells expressing the protein. In comparison, only 1 of the 10 endometrial hyperplasia specimens examined demonstrates an increase in lactoferrin. We also observe distinct cytoplasmic and nuclear immunostaining patterns under different fixation conditions in both normal and malignant epithelial cells, similar to those previously reported in the mouse reproductive tract. Serial sections of malignant specimens show a good correlation between the localization of lactoferrin mRNA and protein in individual epithelial cells by in situ RNA hybridization and immunohistochemistry. Although the degree of lactoferrin expression in the adenocarcinomas did not correlate with the tumor stage, grade, or depth of invasion in these 12 patients, there was a striking inverse correlation between the presence of progesterone receptors and lactoferrin in all 8 lactoferrin-positive adenocarcinomas. In summary, lactoferrin is expressed in a region of normal endometrium known as the zona basalis which is not shed with menstruation and is frequently overexpressed by progesterone receptor-negative cells in endometrial adenocarcinomas.

Mutational analysis of the envelope gene of Moloney murine leukemia virus

The env gene products of Moloney murine leukemia virus are required for binding and entry of the virus into the target cell. Thirty-three linker insertion mutations were constructed throughout the env gene of Moloney murine leukemia virus. Twenty of the mutations were located in the surface protein (SU), and the remaining thirteen were located in the transmembrane protein (TM). The viability of the viruses containing these env gene mutations was determined by performing transient transfections and screening for the release of reverse transcriptase. Eleven viable mutants were isolated, nine in SU and two in TM. Three of the viable mutants were temperature sensitive. Four of the viable mutants were clustered in the carboxy terminus of SU. The env gene products of transfected cell lines which produced viable virus were analyzed. Our results indicated two regions of SU important for the stability of the SU/TM heteropolymer and one region important for the interaction of the env gene products with the viral core.