Computerized Analysis of Magnetic Resonance Images to Study Cerebral Anatomy in Developing Neonates

The study of cerebral anatomy in developing neonates is of great importance for the understanding of brain development during the early period of life. This dissertation therefore focuses on three challenges in the modelling of cerebral anatomy in neonates during brain development. The methods that have been developed all use Magnetic Resonance Images (MRI) as source data. To facilitate study of vascular development in the neonatal period, a set of image analysis algorithms are developed to automatically extract and model cerebral vessel trees. The whole process consists of cerebral vessel tracking from automatically placed seed points, vessel tree generation, and vasculature registration and matching. These algorithms have been tested on clinical Time-of- Flight (TOF) MR angiographic datasets. To facilitate study of the neonatal cortex a complete cerebral cortex segmentation and reconstruction pipeline has been developed. Segmentation of the neonatal cortex is not effectively done by existing algorithms designed for the adult brain because the contrast between grey and white matter is reversed. This causes pixels containing tissue mixtures to be incorrectly labelled by conventional methods. The neonatal cortical segmentation method that has been developed is based on a novel expectation-maximization (EM) method with explicit correction for mislabelled partial volume voxels. Based on the resulting cortical segmentation, an implicit surface evolution technique is adopted for the reconstruction of the cortex in neonates. The performance of the method is investigated by performing a detailed landmark study. To facilitate study of cortical development, a cortical surface registration algorithm for aligning the cortical surface is developed. The method first inflates extracted cortical surfaces and then performs a non-rigid surface registration using free-form deformations (FFDs) to remove residual alignment. Validation experiments using data labelled by an expert observer demonstrate that the method can capture local changes and follow the growth of specific sulcus

Interactions of the Gasotransmitters Contribute to Microvascular Tone (Dys)regulation in the Preterm Neonate

Background & Aims Hydrogen sulphide (H2S), nitric oxide (NO), and carbon monoxide (CO) are involved in transitional microvascular tone dysregulation in the preterm infant; however there is conflicting evidence on the interaction of these gasotransmitters, and their overall contribution to the microcirculation in newborns is not known. The aim of this study was to measure the levels of all 3 gasotransmitters, characterise their interrelationships and elucidate their combined effects on microvascular blood flow. Methods 90 preterm neonates were studied at 24h postnatal age. Microvascular studies were performed by laser Doppler. Arterial COHb levels (a measure of CO) were determined through co-oximetry. NO was measured as nitrate and nitrite in urine. H2S was measured as thiosulphate by liquid chromatography. Relationships between levels of the gasotransmitters and microvascular blood flow were assessed through partial correlation controlling for the influence of gestational age. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow and derive a theoretical model of their interactions. Results No relationship was observed between NO and CO (p = 0.18, r = 0.18). A positive relationship between NO and H2S (p = 0.008, r = 0.28) and an inverse relationship between CO and H2S (p = 0.01, r = -0.33) exists. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow. The model with the best fit is presented. Conclusions The relationships between NO and H2S, and CO and H2S may be of importance in the preterm newborn, particularly as NO levels in males are associated with higher H2S levels and higher microvascular blood flow and CO in females appears to convey protection against vascular dysregulation. Here we present a theoretical model of these interactions and their overall effects on microvascular flow in the preterm newborn, upon which future mechanistic studies may be based.The authors would like to acknowledge the parents of the neonates enrolled in the 2CANS study for their participation, the staff of the Kaleidoscope Neonatal Intensive Care Unit at the John Hunter Children’s Hospital, and Kimberly-Clark Australia for providing the diapers used in this stud

Dichotomous development of the gut microbiome in preterm infants.

BackgroundPreterm infants are at risk of developing intestinal dysbiosis with an increased proportion of Gammaproteobacteria. In this study, we sought the clinical determinants of the relative abundance of feces-associated Gammaproteobacteria in very low birth weight (VLBW) infants. Fecal microbiome was characterized at ≤ 2 weeks and during the 3rd and 4th weeks after birth, by 16S rRNA amplicon sequencing. Maternal and infant clinical characteristics were extracted from electronic medical records. Data were analyzed by linear mixed modeling and linear regression.ResultsClinical data and fecal microbiome profiles of 45 VLBW infants (gestational age 27.9 ± 2.2 weeks; birth weight 1126 ± 208 g) were studied. Three stool samples were analyzed for each infant at mean postnatal ages of 9.9 ± 3, 20.7 ± 4.1, and 29.4 ± 4.9 days. The average relative abundance of Gammaproteobacteria was 42.5% (0-90%) at ≤ 2 weeks, 69.7% (29.9-86.9%) in the 3rd, and 75.5% (54.5-86%) in the 4th week (p < 0.001). Hierarchical and K-means clustering identified two distinct subgroups: cluster 1 started with comparatively low abundance that increased with time, whereas cluster 2 began with a greater abundance at ≤ 2 weeks (p < 0.001) that decreased over time. Both groups resembled each other by the 3rd week. Single variants of Klebsiella and Staphylococcus described variance in community structure between clusters and were shared between all infants, suggesting a common, hospital-derived source. Fecal Gammaproteobacteria was positively associated with vaginal delivery and antenatal steroids.ConclusionsWe detected a dichotomy in gut microbiome assembly in preterm infants: some preterm infants started with low relative gammaproteobacterial abundance in stool that increased as a function of postnatal age, whereas others began with and maintained high abundance. Vaginal birth and antenatal steroids were identified as predictors of Gammaproteobacteria abundance in the early (≤ 2 weeks) and later (3rd and 4th weeks) stool samples, respectively. These findings are important in understanding the development of the gut microbiome in premature infants

Human milk: microbiota composition and impact of processing on probiotic properties

Preterm birth complications represent a leading cause of mortality in children under five years old. To mitigate these complications, strategies such as the use of donor human milk, fortification with human milk fortifiers (protein supplements), and probiotic administration are employed. This thesis aimed to thoroughly understand the microbiota composition of preterm human milk and the influence of various factors on specific probiotics' properties. The study began with analyzing human milk microbiota from healthy Argentinian women across different gestational ages, focusing on changes in microbiota from birth to term equivalent age. It was found that term milk exhibited greater microbial diversity than preterm milk, and by term equivalent age, the microbiota composition of human milk closely resembled that of term milk, suggesting breastfeeding's role in promoting microbial maturity. The research further assessed the stability of probiotics, specifically Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis ssp. lactis Bb12, during cold storage of human milk. Results indicated that these probiotics maintained their viability for up to 72 hours. Additionally, this thesis examined the effect of liquid or powdered human milk fortifiers on the adhesion properties of these probiotics in donor human milk, finding that fortification did not adversely affect probiotic adhesion. The final study of the thesis explored the role of polyamines, in modulating the adhesion of probiotics and pathogens with intestinal mucus in infants. The presence of the polyamine spermidine significantly enhanced the adhesion of Bb12 in infant mucus under six months, whereas the polyamine spermine reduced the adhesion of Cronobacter sakazakii. In conclusion, the thesis showed that the microbiota profiles of human milk significantly vary with gestational age. A key finding is that the microbiota composition of preterm human milk undergoes a transformation, eventually resembling that of term milk as the infant reaches term equivalent age. It was also found that probiotic adhesion properties are unaffected by cold storage or the fortification of donor human milk. However, the influence of polyamines on bacterial adhesion to mucus varies based on the bacterial strain and the mucus donor's age employed. These insights should be considered for developing optimized gut colonization strategies for infants, particularly for those born preterm.Äidinmaito: mikrobiston koostumus ja prosessoinnin vaikutus sen probioottisiin ominaisuuksiin Ennenaikaisen synnytyksen komplikaatiot ovat yleisin alle viisivuotiaiden lasten kuolinsyy. Luovutettua äidinmaitoa, äidinmaidon täydentämistä proteiinilisällä sekä probioottien antamista käytetään näiden komplikaatioiden ehkäisemiseksi. Tämän opinnäytetyön tavoitteena oli selvittää ennenaikaisesti synnyttäneiden äitien rintamaidon mikrobistokoostumusta ja eri tekijöiden vaikutusta tiettyjen probioottien ominaisuuksiin. Tutkimuksessa analysoitiin terveiden argentiinalaisten naisten äidinmaidon mikrobikoostumusta keskittyen mikrobiston muutoksiin ennenaikaisesta synnytyksestä laskettuun aikaan. Huomattiin, että täysiaikaisesti synnyttäneiden naisten äidinmaidon mikrobiston monimuotoisuus oli suurempaa kuin ennenaikaisesti synnyttäille naisilla. Laskettuna aikana ennenaikasesti synnyttäneiden äidinmaidon mikrobikoostumus muistutti läheisesti täysiaikaisen maidon mikrobistoa, mikä viittaa siihen, että imetyksellä on tärkeä rooli mikrobiston kypsymisen edistämisessä. Tutkimuksessa, jossa arvioitiin Lacticaseibacillus rhamnosus GG:n ja Bifidobacterium animalis ssp. lactis Bb12 -probioottien stabiiliutta äidinmaidossa kylmävarastoinnin aikana, nämä probiootit säilyttivät elinkykynsä jopa 72 tuntia. Lisäksi havaittiin, että äidinmaidon vahvistaminen nestemäisellä tai jauhemaisella vahvikkeella ei vaikuttanut haitallisesti probioottien tarttumisominaisuuksiin luovutetussa äidinmaidossa. Opinnäytetyön viimeisessä tutkimuksessa selvitettiin polyamiinien roolia bakteerien tarttumisen säätelyssä imäveisen suolistolimassa. Polyamiini spermidiinin läsnäolo paransi merkittävästi Bb12:n kiinnittymistä alle kuuden kuukauden ikäisen imeväisten limaan, kun taas spermiini vähensi Cronobacter sakazakii-bakteerin tarttumista. Opinnäytetyö osoitti, että äidinmaidon mikrobistoprofiilit vaihtelevat merkittävästi raskauden keston mukaan. Ennenaikaisen synnytyksen jälkeen äidinmaidon mikrobistokoostumus muuttuu ja alkaa lopulta muistuttaa täysiaikaisen synnytyksen äidinmaidon mikrobistokoostumusta vauvan saavuttaessa taysiaikaista vastaavan iän. Lisäksi havaittiin, että kylmävarastointi tai luovutetun äidinmaidon vahvistaminen eivät vaikuttaneet probioottien tarttumisominaisuuksiin. Polyamiinien vaikutus bakteerien tarttumiseen limaan vaihtelee bakteerikannan ja limanluovuttajan iän mukaan. Tulokset auttavat kehittämään optimoituja suoliston kolonisaatiostrategioita vastasyntyneille ja erityisesti keskosille

Role of the advanced MRI sequences in predicting the outcome of preterm neonates

AIM The aim of the project is to evaluate the role of advanced MRI sequences (susceptibility weight imaging (SWI), diffusion tensor imaging (DTI), and arterial spin labeling (ASL) perfusion) in detecting early changes that affect preterm neonatal brain, especially in those patients without lesions at conventional MRI or with small brain injuries (i.e. low grade germinal matrix-intraventricular hemorrhage (GMHIVH)), and to correlate these subtle brain abnormalities with neurodevelopmental outcome at 24 months. METHODS Since November 2015 until June 2017, 287 preterm neonates and 108 term neonates underwent a 3T or 1.5T MRI study at term corrected age (40\ub11 weeks). SWI, DTI and ASL sequences were performed in all neonates. SWI sequences were evaluated using both a qualitative (SWI venography) and quantitative (Quantitative Susceptibility Map analysis (SWI-QSM)) approach. DTI data were analyzed using a Tract-Based Spatial Statistics analysis (TBSS). ASL studies were processed to estimate Cerebral Blood Flow (CBF) maps. Perinatal clinical data were collected for all neonates. Neurodevelopmental data were evaluated at 24 months in 175 neonates using 0-2 Griffiths Developmental Scales. RESULTS The analysis performed on SWI-venography revealed differences in subependymal veins morphology between preterm and term neonates with normal brain MRI, with a higher variability from the typical anatomical pattern in preterm neonates. The same analysis performed in preterm neonates with GMH-IVH revealed that the anatomical features of subependymal veins may play a potential role as predisposing factor for GMH-IVH. Moreover, the SWI-QSM analysis revealed a greater paramagnetic susceptibility in several periventricular white matter (WM) regions in preterm neonates with GMH-IVH than in healthy controls. This finding is likely related to the accumulation of hemosiderin/ferritin following the diffusion of large amounts of intraventricular blood products into the WM, and it is also supposed to trigger the cascade of lipid peroxidation and free radical formation that promote oxidative and inflammatory injury of the WM in neonatal brain after GMH-IVH. The TBSS analysis confirmed that microstructural WM injury can occur in preterm neonates with low grade GMH-IVH even in the absence of overt signal changes on conventional MRI, with different patterns of WM involvement depending on gestational age. Moreover, the distribution of these WM microstructural alterations after GMH-IVH correlates with specific neurodevelopmental impairments at 24 months of age. Finally, the analysis of brain perfusion at term-corrected age revealed lower CBF in preterms with sub-optimal neuromotor development, reinforcing the hypothesis that impaired autoregulation of CBF may contribute to the development of brain damage in preterm neonates. CONCLUSION Advanced MRI sequences can assist the standard perinatal brain imaging in the early diagnosis of preterm neonatal brain lesions and can provide new insights for predicting the neurodevelopmental trajectory. However, detailed and serial imaging of carefully chosen cohorts of neonates coupled with longer clinical follow-up are essential to ensure the clinical significance of these novel findings

Fetal and early neonatal interleukin-6 response

In 1998, a systemic fetal cytokine response, defined as a plasma interleukin-6 (IL-6) value above 11 pg/mL, was reported to be a major independent risk factor for the subsequent development of neonatal morbid events even after adjustments for gestational age and other confounders. Since then, the body of literature investigating the use of blood concentrations of IL-6 as a hallmark of the fetal inflammatory response syndrome (FIRS), a diagnostic marker of early-onset neonatal sepsis (EONS) and a risk predictor of white matter injury (WMI), has grown rapidly. In this article, we critically review: IL-6 biological functions; current evidence on the association between IL-6, preterm birth, FIRS and EONS; IL-6 reference intervals and dynamics in the early neonatal period; IL-6 response during the immediate postnatal period and perinatal confounders; accuracy and completeness of IL-6 diagnostic studies for EONS (according to the Standards for Reporting of Diagnostic Accuracy statement); and recent breakthroughs in the association between fetal blood IL-6, EONS, and WMI

Improving quality of care and outcome at very preterm birth: the Preterm Birth research programme, including the Cord pilot RCT

BACKGROUND:Being born very premature (i.e. before 32 weeks’ gestation) has an impact on survival and quality of life. Improving care at birth may improve outcomes and parents’ experiences. OBJECTIVES:To improve the quality of care and outcomes following very preterm birth. DESIGN:We used mixed methods, including a James Lind Alliance prioritisation, a systematic review, a framework synthesis, a comparative review, qualitative studies, development of a questionnaire tool and a medical device (a neonatal resuscitation trolley), a survey of practice, a randomised trial and a protocol for a prospective meta-analysis using individual participant data. SETTING:For the prioritisation, this included people affected by preterm birth and health-care practitioners in the UK relevant to preterm birth. The qualitative work on preterm birth and the development of the questionnaire involved parents of infants born at three maternity hospitals in southern England. The medical device was developed at Liverpool Women’s Hospital. The survey of practice involved UK neonatal units. The randomised trial was conducted at eight UK tertiary maternity hospitals. PARTICIPANTS:For prioritisation, 26 organisations and 386 individuals; for the interviews and questionnaire tool, 32 mothers and seven fathers who had a baby born before 32 weeks’ gestation for interviews evaluating the trolley, 30 people who had experienced it being used at the birth of their baby (19 mothers, 10 partners and 1 grandmother) and 20 clinicians who were present when it was being used; for the trial, 261 women expected to have a live birth before 32 weeks’ gestation, and their 276 babies. INTERVENTIONS:Providing neonatal care at very preterm birth beside the mother, and with the umbilical cord intact; timing of cord clamping at very preterm birth. MAIN OUTCOME MEASURES:Research priorities for preterm birth; feasibility and acceptability of the trolley; feasibility of a randomised trial, death and intraventricular haemorrhage. REVIEW METHODS:Systematic review of Cochrane reviews (umbrella review); framework synthesis of ethics aspects of consent, with conceptual framework to inform selection criteria for empirical and analytical studies. The comparative review included studies using a questionnaire to assess satisfaction with care during childbirth, and provided psychometric information. RESULTS:Our prioritisation identified 104 research topics for preterm birth, with the top 30 ranked. An ethnographic analysis of decision-making during this process suggested ways that it might be improved. Qualitative interviews with parents about their experiences of very preterm birth identified two differences with term births: the importance of the staff appearing calm and of staff taking control. Following a comparative review, this led to the development of a questionnaire to assess parents’ views of care during very preterm birth. A systematic overview summarised evidence for delivery room neonatal care and revealed significant evidence gaps. The framework synthesis explored ethics issues in consent for trials involving sick or preterm infants, concluding that no existing process is ideal and identifying three important gaps. This led to the development of a two-stage consent pathway (oral assent followed by written consent), subsequently evaluated in our randomised trial. Our survey of practice for care at the time of birth showed variation in approaches to cord clamping, and that no hospitals were providing neonatal care with the cord intact. We showed that neonatal care could be provided beside the mother using either the mobile neonatal resuscitation trolley we developed or existing equipment. Qualitative interviews suggested that neonatal care beside the mother is valued by parents and acceptable to clinicians. Our pilot randomised trial compared cord clamping after 2 minutes and initial neonatal care, if needed, with the cord intact, with clamping within 20 seconds and initial neonatal care after clamping. This study demonstrated feasibility of a large UK randomised trial. Of 135 infants allocated to cord clamping ≥ 2 minutes, 7 (5.2%) died and, of 135 allocated to cord clamping ≤ 20 seconds, 15 (11.1%) died (risk difference –5.9%, 95% confidence interval –12.4% to 0.6%). Of live births, 43 out of 134 (32%) allocated to cord clamping ≥ 2 minutes had intraventricular haemorrhage compared with 47 out of 132 (36%) allocated to cord clamping ≤ 20 seconds (risk difference –3.5%, 95% CI –14.9% to 7.8%). LIMITATIONS:Small sample for the qualitative interviews about preterm birth, single-centre evaluation of neonatal care beside the mother, and a pilot trial. CONCLUSIONS:Our programme of research has improved understanding of parent experiences of very preterm birth, and informed clinical guidelines and the research agenda. Our two-stage consent pathway is recommended for intrapartum clinical research trials. Our pilot trial will contribute to the individual participant data meta-analysis, results of which will guide design of future trials. FUTURE WORK:Research in preterm birth should take account of the top priorities. Further evaluation of neonatal care beside the mother is merited, and future trial of alternative policies for management of cord clamping should take account of the meta-analysis. STUDY REGISTRATION:This study is registered as PROSPERO CRD42012003038 and CRD42013004405. In addition, Current Controlled Trials ISRCTN21456601. FUNDING:This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 7, No. 8. See the NIHR Journals Library website for further project information

Probiotic administration in congenital heart disease: a pilot study.

ObjectiveTo investigate the impact of probiotic Bifidobacterium longum ssp. infantis on the fecal microbiota and plasma cytokines in neonates with congenital heart disease.Study designSixteen infants with congenital heart disease were randomly assigned to receive either B. infantis (4.2 × 10(9) colony-forming units two times daily) or placebo for 8 weeks. Stool specimens from enrolled infants and from six term infants without heart disease were analyzed for microbial composition. Plasma cytokines were analyzed weekly in the infants with heart disease.ResultsHealthy control infants had increased total bacteria, total Bacteroidetes and total bifidobacteria compared to the infants with heart disease, but there were no significant differences between the placebo and probiotic groups. Plasma interleukin (IL)10, interferon (IFN)γ and IL1β levels were transiently higher in the probiotic group.ConclusionCongenital heart disease in infants is associated with dysbiosis. Probiotic B. infantis did not significantly alter the fecal microbiota. Alterations in plasma cytokines were found to be inconsistent