RECENT ADVANCES IN OUR UNDERSTANDING & MANAGEMENT OF NEC

Transcription

1 RECENT ADVANCES IN OUR UNDERSTANDING & MANAGEMENT OF NEC Prof. Minesh Minesh Khashu Consultant Neonatologist & Prof. of Perinatal 1

2 Plan Aim & Learning outcomes Introduction to SIGNEC Important recent developments in our understanding of NEC What does it mean for clinical practice? Key take home messages

3 Aim & Learning Outcomes Improve understanding of current research domain for NEC, recent advances in our understanding of NEC, potential new therapies and implications for clinical practice Improve understanding of aim/objectives of SIGNEC

4 Prof. Minesh 4

5 Leading cause of death from GI disease in the premature infant Etiology remains incompletely understood Despite over 6 decades of research the mortality of NEC remains unchanged and is as high as 50% NEC is still a disease for which there is currently no known cure

6 (Ahle et al: Pediatrics 2013) NEC is not going away

7 Mortality rate (deaths/1000 live births) NEC mortality (UK data) ELBW (p=0.0005) infant (p<0.0001) Year NEC (p=ns) (p<0.0001)

8 Surgical NEC mortality 1990s vs 2000s (Fasoli et al: JPS 1999; Thyoka et al: Eur J Pediatr Surg 2012)

9 Neurodevelopmental Impairment No NEC vs. NEC Chacko et al ns Hintz et al Holmsgaard et al ns Sonntag et al Tobiansky et al ns Walsh et al ns Combined 1.3 < RR p (Rees et al: Arch Dis Child 2009)

10

11 NEC outcomes Incidence is increasing Despite improvements in neonatal care and an overall decrease in infant mortality, mortality from NEC has not decreased In survivors, NEC is increasingly recognised as a risk factor for neurodevelopmental impairment

12 Prof. Minesh 12

13 SIGNEC U.K. includes neonatologists, paediatricians, surgeons, dieticians, transfusion medicine specialists, epidemiologists, basic science researchers, nurses, trainees and other healthcare professionals with an interest in NEC and healthcare improvement

14 The aim is to facilitate knowledge sharing, networking and collaboration to optimise research and improvements in practice

15 Make a difference by sharing your thoughts and passion and contributing your expertise Correspondence: Prof. Minesh Khashu, Consultant in Neonatal Medicine, Poole Hospital NHS Foundation Trust mineshkhashu@gmail.com

16 SIGNEC International Conferences on Necrotising Enterocolitis

17 NEC: Why & How Genetics & Immunology Environment

18 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

19 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

20 Gestational age What is the reason for NEC vulnerability? A Discrete Window of NEC Vulnerability Day of NEC onset Barbara Warner and Phil Tarr s Cincinnati group were the first to actually publish that the timing of NEC onset tightly correlates with gestational age at birth. This is known as being consistent with Sartwell s model of disease onset

21 Professor Phillip V. Gordon, USA

22 Window of vulnerability/window of opportunity The timing of NEC onset tightly correlates with gestational age at birth. The younger the gestational age, the later the development of NEC. The incidence of NEC peaks at 33 weeks post-menstrual age.

23 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

24 What is the reason for NEC vulnerability? Expression of TLR-4 in the intestinal epithelial cells The role of TLR4 signaling in the pathogenesis of necrotizing enterocolitis. As described in bacterial over-growth / imbalance, hypoxia, infection, and prematurity together increase the expression of TLR4 in the intestinal mucosa, whose subsequent activation by enteric bacteria leads to increased barrier injury and reduced epithelial repair. Inhibition of TLR4, as may occur via activation of the cytoplasmic innate immune receptors NOD2 and TLR9 leads to an inhibition of TLR4, restoration of the intestinal epithelial barrier, and a reduction in the severity of NEC.

25 TLR4, receptor for Gram negative bacteria, plays a critical role in NEC pathogenesis. TLR4 activation within the intestinal mucosa leads to the death of intestinal epithelial cells, impaired intestinal stem cell proliferation & reduced mucosal perfusion. TLR4 expression is elevated in the intestinal tract of the premature infant, which is a consequence of the role of TLR4 in regulating normal gut differentiation during embryonic development. Professor David J. Hackam Chief of Pediatric Surgery, John Hopkins Children s Center, USA

26 Preterm intestine is characterised by excessive TLR4 expression, leading to the development of NEC when colonising microbes activate TLR4. Professor Hackam s team have developed novel small molecule inhibitors of TLR4, which effectively treat NEC in small and large animal models. These findings provide insights into the pathogenesis of this disease and offer novel and exciting therapeutic approaches.

27 How does NEC happen? Hypoxia Hackam et al. Clin Dev Immunol

28 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

29 What is the reason for NEC vulnerability? Reduced TGF-b 2 in neonatal intestinal epithelial cells TGF-b 2 paucity makes macrophages hypersensitive to bacteria Incomplete development of macrophage tolerance to bacterial products predisposes the preterm intestine to NEC. In the mature intestine (schematic representation on the left), epithelial and stromal cell-derived TGF-β attenuates the inflammatory responses of intestinal macrophages to luminal bacteria or their products. In contrast, in the premature infant (right), the inflammatory responses of intestinal macrophages remain intact because TGF-β expression, and therefore, mucosal tolerance to bacterial products, are deficient. Bacterial products trigger an intense inflammatory reaction, causing widespread tissue damage. Enteral supplementation of recombinant TGF-β 2 is a potential therapeutic strategy to prevent NEC in neonates.

30 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

31 What is the reason for NEC vulnerability? Transition from innate to adaptive immunity (T-cell ontogeny) The T-reg. Hammer! 1 week 2 weeks 3 weeks In mice, T-cells appear over several weeks in the postnatal period. In humans, T-reg. cells are present by 24 weeks gest. but are significantly lower in infants who have NEC versus controls. (T-reg maturation stops the NEC time clock)

32 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

33 Dr Paolo De Coppi described how stem cells taken from amniotic fluid were used to restore gut structure and function following intestinal damage in rodents. Stem cells are known to have anti-inflammatory effects; 1 st time it has been shown they can repair damage in the intestines. Modality holds significant promise and needs to be explored

34 The consequences of chorioamnionitis on fetal gut development are adverse Experimental models of chorioamnionitis with ureaplasma show a severe impairment of gut structure. Complex dysregulation of the fetal immune system, resulting in a hypo-responsiveness of immune cells to endotoxin from E. coli. The intrauterine conditioning of the fetal immune system may predispose an already injured gut to subsequent injury resulting in NEC.

35 GENETICS & IMMUNOLOGY ENVIRONMENT GESTATIONAL AGE GENETICS e.g. POLYMORPHISMS INFECTION/ INFLAMMATION MICROBIOME TLR4 TGF b2 T cell ontogeny TIMING OF INFLAMMATION FECAL VS TISSUE MICROBIOME ABSOLUTE PHYLA VS DIVERSITY

36

37 Fecal microbiome studies comparing infants with and without NEC Decreased microbial diversity in NEC More antibiotic use in NEC Twin studies: Increased Proteobacteria and less diversity in NEC Wang Y et al. ISME J 2009

38 NEC tissue microbiome: Loss of rare phyla and Actinobacteria but large increase in Firmicutes Controls 11% 10% 6% 16% 55% NEC Firmicutes Actinobacteria Proteobacteria Bacteroidetes Phyla <1% abundance 24% 5% 14% 4% 52%

39 Relative Abundance NEC in first 3 weeks dominated by Staphylococci Early NEC Late NEC Morrow L et al., Microbiome 2013

40

41 Establishment of the microbiota in infancy Facultative Anaerobes O 2 Obligate Anaerobes Antibiotic s NEC - Antibiotic use - Diversity Immunity PTB, PROM IgA - Actinobacteria - Firmicutes (early) - Proteobacteria (later) Chorioamnionitis, Intrapartum antibiotics Breast milk Formula Lactobacillus Bifidobacteria Clostridium difficile Bifidobacterium fragilis Escherichia coli Stability - Staphylococci (tissue) Future Strain- and metabolicresolved genomic data F. prausnitzii R. hominis Modified from Clemente JC et al., Cell 2012

42

43 Conclusions PiPS This intervention was not associated with any advantage in this population of babies. This result highlights the need to assess the efficacy of different probiotic strains and challenges the validity of combining trials using different probiotic interventions in meta-analyses. B breve, n=650 Placebo, n=660 Adjusted RR (95% CI) NEC=Bell stage 2 61 (9.4%) 66 (10.0%) 0.93 (0.68 to 1.27) LOS 73 (11.2%) 77 (11.7%) 0.97 (0.73 to 1.29) Death 54 (8.3%) 56 (8.5%) 0.93 (0.67 to 1.30)

44

45 Are Paneth cells a missing link? Proposed New Pathophysiology of NEC Any acute insult may disrupt Paneth cell homeostasis This leads to further dysbiosis, barrier failure, and inflammation Allows for bacterial penetration and subsequent disease

46 Paneth cell disruption alters the normal microbiome

47 Mechanism of breast milk protection against NEC Breast milk is protective against NEC by inhibiting TLR4 with the activation of EGFR. EGFR signaling protected against TLR4- mediated enterocyte apoptosis and enhanced enterocyte proliferation in NEC. Thus, it is particularly important to study the gene regulation of EGFR in NEC as a therapeutic or preventative target in NEC.

48 Amniotic fluid attenuates NEC severity via EGFR Good et al, PNAS, 2012

49 MicroRNA Background Noncoding RNA about 22 nucleotides long Function in RNA silencing and therefore post-transcriptional regulation of gene expression Initially expressed as pri-mirnas in clusters that undergo post-transcriptional processing to produce mature mirnas

50 Observation: mirnas are known to be differentially expressed in intestinal inflammatory states Hypothesis: mirnas are differentially expressed in premature infants with NEC

51 Relative mirna-17 Expression Serum MiR-17 is increased in medical and surgical NEC 60 * 40 * 20 0 Control Medical NEC Surgical NEC *P<0.05 Pompa et al, in preparation

52 Conclusions The mirna-17~92 cluster is up-regulated in the intestines of infants with NEC (medical and surgical NEC) MiR-17 targets EGFR mirna-17 may play an important role in the maintenance of the gut barrier and in NEC pathogenesis

53 UK NC NEC STUDY Despite significant difference in feeding practices in various networks, rates of NEC not significantly different Early feeding of babies with their own mother s milk and avoidance of bovine-origin products might reduce the risk of necrotising enterocolitis, but the absolute reduction is small Severe NEC rates EARLY vs LATE or NO MBM: RR 0.69; NNT 114 Severe NEC rates NO vs SOME BOVINE: 0.61; NNT 154 NEC score and GA specific case definition

54 During the study period, babies were admitted to 163 neonatal units across 23 networks, of whom were born before a gestational age of 32 weeks. 531 (0 4%) babies developed severe necrotising enterocolitis, of whom 247 (46 5%) died (139 after laparotomy). 462 (3 2%) of babies born before a gestational age of 32 weeks developed severe necrotising enterocolitis, of whom 222 (48 1%) died. The absolute risk difference for babies born before a gestational age of 32 weeks who received their own mother s milk within 7 days of birth was 0 88% (95% CI 1 15 to 0 61; relative risk 0 69, 95% CI 0 60 to 0 78; NNT to prevent one case of necrotising enterocolitis 114, 95% CI 87 to 136). For babies who received no compared with any bovine-origin products within 14 days of birth, the absolute risk difference was 0 65% ( 1 01 to 0 29; relative risk 0 61, 0 39 to 0 83; NNT 154, 99 to 345). Unable to assess the effect of human donor milk as use was low.

55 Incidence of NEC in Canada Medical NEC Surgical NEC

56 Potential Benefits of Using Donor Milk as a Supplement A higher incidence of NEC among infants fed formula vs. donor milk (Relative Risk of 2.5 [95% CI, 1.2, 5.1]) Quigley MA et al Cochrane Database Syst Rev 2007:CD002971

57 Necrotizing Enterocolitis? The Japanese Way

58 NEC Incidence: Canada & Japan

59 Japanese NEC prevention Strategy Exclusive breast milk feeding for <28 weeks Unpasteurised breast milk Aggressive feeding full feeds in one week Avoid umbilical catheters Early use of PIC lines to reduce skin breaks Use antibiotics only if evidence of infection Transpyloric feeding catheters Probiotics Glycerin enema Minimal handling Encourage developmental & kangaroo care

60 Is There An Advantage of an Exclusive Human Milk Diet for NEC Prevention? Mothers own milk comprised ~ 70% of feedings > 50% in NEC Reduction in surgical NEC *Sullivan et al Journal of Pediatrics 2010;156:562-7.

61 Absent flow on US: 100% sensitivity for necrotic bowel 95% specificity

62 What can we do differently tomorrow? New Therapies Early detection Prevention EXCELLENT COMMUNICATION EASILY ACCESSIBLE RESOURCES GOOD QUALITY RESEARCH

63 Prof. Minesh 63

64 Prof. Minesh 64

65 What can we do differently tomorrow? New Therapies Early detection Prevention EXCELLENT COMMUNICATION EASILY ACCESSIBLE RESOURCES GOOD QUALITY RESEARCH

66 Parent presentations SIGNEC Need for consistent, reliable information for parents/families. Optimising Transfers Need for more knowledge of long-term outcomes. Improved family-centred care, especially during the post-surgical period.

67

68

69

70

71 Prematurity Chorioamnionitis Prevention Breast milk Colostrum Probiotics (? Better products & delivery) Rationalise antibiotic use

72 Early detection DOVE STUDY : volatile compounds FECAL PRINT : bio map and diversity HEART RATE CHARACTERISTICS

73 Vital sign abnormalities in Systemic Inflammation (SIRS) T RR HR BP Fairchild, Current Opinion in Pediatrics 2013

74 Autonomic nervous system control of heart rate characteristics in SIRS, sepsis, NEC Fairchild, O Shea 2010 Clinics in Perinatology

75 New Therapies TLR4 receptor antagonist IL-1 receptor antagonist Amniotic fluid stem cells Probiotics as Biofilm Growth factors

76 1) C-section Hypoxia Hypothermia HB-EGF Hypertonic feeds + LPS CLINICAL NEC Newborn mice and rats

77 100 m Breast Fed NEC NEC+HB-EGF 5 µm 20 m

78 IEC migration IEC proliferation IEC apoptosis NF-κB activation Decreases bacterial translocation Preserves gut barrier function Preserves villous microvascular blood flow HB-EGF pro-inflammatory cytokine production inos expression and overproduction of NO PMN-EC interactions enos expression potent vasodilator PMN/ MΦ infiltration ROS production

79 Clinical Observations: ENS immaturity in preterms poor intestinal motility vulnerability to NEC Intestinal dysmotility is common after NEC suggesting ENS injury during NEC Enteric nervous system abnormalities are present in human necrotizing enterocolitis: potential neurotransplantation therapy. Zhou Y, Yang J, Watkins DJ, Boomer LA, Matthews MA, Su Y, Besner GE. Stem Cell Res Ther Dec 25;4(6):157. Research findings from Human NEC specimens : Enteric neurons and glial cells are injured during human and experimental NEC These abnormalities persist even months after survival from the acute disease Could transplantation of NSC protect the intestines from NEC?

80 In our experimental NEC model, administration of NSC: protects the ENS from histologic injury preserves gut barrier function increases survival Administration of HB-EGF + NSC further protects the intestines from NEC Genetic engineering of NSC to overexpress HB-EGF further protects the intestines from NEC

81 SC administered IV or IP preferentially engraft into injured intestine SC can protect the intestines from NEC Different types of SC have equivalent efficacy in protecting the intestines from NEC However... IV, many SC are trapped in the lungs have been implicated in tumor formation

82 SC-derived exosomes: engraft into injured intestine as effective as SC in protecting the intestines from NEC may be a novel non-cell based future therapy for NEC

83 Must be given at least daily Several case reports of bacteremia Do not significantly alter host microbiome

84 A single dose of Lactobacillus reuteri administered as a biofilm decreases the incidence of NEC and preserves gut barrier function L. reuteri grown on sucrose- or maltose-loaded microspheres: have improved resistance to gastric acid have improved adherence to intestinal epithelial cells in vitro have improved ability to colonize intestine in vivo further decreases NEC incidence and improves gut barrier function Optimizing delivery strategies may significantly improve probiotic efficacy

85 Potential Nutritional therapies for NEC Vongbhavit et al. Prevention of necrotising enterocolitis through manipulation of the intestinal microbiota in the premature infant. Clin Ther 2016;38:

86 Not so new therapy Colostrum Baby s first immunisation Best start to life!

87 Take home messages Window of vulnerability Breast milk especially COLOSTRUM Quality Improvement (BF rates, antibiotics, standardized feeding regimens, Infection) Communication & collaboration with parents/families Data & Research Some potentially exciting developments

88 As you think about interventions in your respective units Prof. Minesh 88

89 Prof. Minesh 89

90 Prof. Minesh

91 Parent Information leaflets What is NEC and why do babies get it? Many babies with NEC do not need surgery (medical management of NEC) Some babies with NEC require surgery What can I do to decrease the risk of NEC for my baby?

92 RESEARCH Is it one disease or a final common pathway? If it is one disease, are there subtypes of NEC? Breast milk, donor milk, colostrum, substitutes New molecules Evaluation of therapies

93

94 Cytokines transient HR decelerations, then decreased HR variability E. coli LPS, TNF, or IL-6 Am J Physiol 2009 Pathogens Vagus nerve activation transient repetitive HR decelerations Intraperitoneal Klebsiella, MRSA, or Candida Am J Physiol 2011

95 UVA apnea detection system Lee et al, A New Algorithm for Detecting Central Apnea in Preterm Infants, Physiol Meas 2012 Automated algorithm analyzes chest impedance waveforms and vital signs for ABD events Periodic breathing Repetitive, regular cycles of apnea/breathing Physiologic, but if exaggerated may be pathologic May be associated with small drops in heart rate and SpO2

96 Prof. Minesh

97 Potential Conflict of interest We need to be aware of the potential Both clinicians and industry colleagues endorse that: *Breast milk is the best option for babies *In preterm babies mother s breast milk has a protective effect against NEC However some newborns especially preterm ones may need further protein or energy supplementation for growth or breast milk may not be available for medical reasons or based on informed choice of mother. For such situations formula milk may be required and it is in the best interests of all parties that we set priorities for research Prof. Minesh 97

98

99

100 Host-specific microbiome Spor A, Koren O, Ley R, Nat Rev Microbiol 2011

101 Reducing Necrotizing Enterocolitis using Breast Milk: the Canadian experience Shoo Lee, MBBS, FRCPC, PhD Scientific Director, Institute of Human Development, Child & Youth Health, Canadian Institutes of Health Research Professor of Paediatrics, Obstetrics & Gynecology, and Public Health, University of Toronto; Paediatrician-in-Chief, Mount Sinai Hospital;

102 Is There An Advantage of an Exclusive Human Milk Diet for NEC Prevention? Infants fed mothers own milk randomized to: 1. HM HM40 Pasteurized donor milk + human milk fortifier 3. BOV Preterm formula + bovine milk fortifier *Sullivan et al Journal of Pediatrics 2010;156:562-7.

103 # Publications HB-EGF protects the brain from stroke HB-EGF protects the heart from myocardial infarction HB-EGF protects the kidneys, bladder and liver from injury HB-EGF protects the intestines from various forms of injury including NEC