Necrotizing Enterocolitis: An Update. Josef Neu, M.D.

Transcription

1 Necrotizing Enterocolitis: An Update Josef Neu, M.D.

2 Classic NEC A B C Neu, J. and Walker, W. A. New England Journal of Medicine, Jan. 2011

3 Agenda Background Different forms of NEC Pathogenesis: Classic NEC Can we develop predictive and/or diagnostic biomarkers? Preventative Strategies

4 Necrotizing Enterocolitis: Scope of the Problem In US and Canada, it affects approximately 7% of babies weighing between grams (approximately 20-30% die). Approximates the number of children fewer than 15 years of age who die of leukemia or meningitis. Survivors may be left with significant sequelae. Very costly. Scares neonatologists!

5 Being led astray: 50 years--- not much progress Lumping of several diseases called NEC into the same data set. Animal models that do not represent the disease. Human surgical samples that probably represent degrading tissue.

6 More than one disease or one disease with many origins? Ischemic intestine cardiogenic, polycythemia, severe IUGR with abnormal Doppler flow. Intestinal anomalies--- Hirschprung s, malrotation, intussusception, etc. Spontaneous Intestinal Perforations (SIPs)

7 More than one disease or one disease with many origins? Variant of food protein induced enterocolitis syndrome (FPIES) prbc infusions Inflammatory, Dysbiosis--- Classic NEC in preterms.

8 Right after birth 12 hours later

9

10 Isolated Non-NEC Perforations Occurs early. Not related to feedings (except for possibly the lack of feedings). Related to combined early dexamethasone (or hydrocortisone)and indomethacin (Stark, et al. NEJM,2001;Gordon, et al. J. Perinatol., 1999: Watterbert, 2004).

11

12 Is there a Clear Definition of NEC? Bells is Broken Stage 1-Too nonspecific and the term should not be used. Stage 3- Could signify intestinal necrosis or Spontaneous Intestinal Perforation

13 What Causes NEC?

14

15 Postmenstrual Age Difference

16 Neu, J. Acta Paediatrica, (Supple 449): A.R. Llanos, et al., Paediatr Perinat Epidemiol, (4):

17 NEC: Relation to Inflammatory Mediators Increased plasma pro-inflammatory cytokine (IL-8. Il1, IL-6, TNF-α ) concentrations. Increased platelet activating factor.

18 Classic NEC: Do the Microbiota Differ? A B C Neu, J. and Walker, W. A. New England Journal of Medicine, Jan. 2011

19 FECAL MICROBIOTA: NEC Mai V, Young C. PLOS One, May 2011 Proportions of the four major phyla two weeks before and the week of diagnosis

20 Microbial Shift Prior to NEC From Claud, E. et al. Microbiome, 2013

21 Proteobacteria Major Phylum of bacteria Includes a wide variety of pathogens (E.coli, Salmonella, Vibrio, Helicobacter, Klebsiella, Pseudomonas,etc.). Gram negative with outer membrane composed of lipopolyscaccharide. Have been associated with exacerbations of intestinal inflammation and IBD.

22 Lack of Enteral Feeding; TPN, Intestinal ph Antibiotics and Microbial Environment Type of Diet: Human Milk versus Formula Inappropriate Colonization DYSBIOSIS

23 Does Feeding or Lack of Enteral Feeding Affect the Microbiome? Excuses To Withhold ENTERAL Feedings Low APGAR scores. Umbilical catheters. Apnea and Bradycardia. Mechanical ventilation. CPAP. Vasoactive drugs. TPN is available.

24 Effect of Total Parenteral Nutrition (TPN) in Mice Demehri, FR., et al. Cellular and Infection Microbiology, Dec. 2013

25 Demehri, FR., et al. Cellular and Infection Microbiology, Dec. 2013

26 TOP TEN LIST OF NICU MEDICATIONS Clark RH, et al. Pediatrics 2006;117:

27 Odds ratio of NEC with increased days on antibiotics Alexander, V.N. J. Pediatrics, Sept. 2011

28 Effect of Antibiotics on Colonization Resistance Ng, KM., et al. Nature. Vol 502, 3 Oct 2013, and Stecher, B. Cell Host & Microbe 14, September 11, 2013

29 Does Intestinal ph Matter for the Microbiome? Gastric Acid Secretion Hyman, PE, et al J Pediatr Mar;106(3):

30 Gastric Acid Inhibition Pediatrics, 2012, 129. e-40-45

31 Duncan, S.H., et al. Environmental Microbiology, 2009, 11(8),

32 Dysbiosis and NEC: Conclusions May start before birth. We have suggested associations between certain taxa of bacteria and NEC which make sense. Causation (fulfillment of Koch s postulates) not complete. Many factors still unkown: transcriptomics, metabolomics, microbial host interactions.

33 NEC: A Diagnostic Dilemma

34 Why are new biomarkers needed for NEC? Current diagnosis based on history, physical exam, radiographic criteria detects the disease after it s occurrence when it may already be too late. Diagnostic biomarkers would enhance our diagnostic capabilities. Predictive biomarkers would tell us which infants are at highest risk so that we could provide targeted prevention.

35 Diagnostic Biomarker Types Non Specific Inflammatory Biomarkers Platelet count White Blood count and Immature: Total ratios C-reactive protein Procalcitonin Serum amyloid A Cytokines Neutrophil CD64 Not helpful in differentiating NEC from sepsis!

36 Diagnostic Biomarker Types Enhanced non-specific Biomarkers Fecal Calprotectin (S100A9) Fecal Calgranulin C(S100A12) Gut Associated Biomarkers Intestinal Fatty Acid Binding Protein (I-FABP) Claudin 3

37 CRP, WBC and PLATELETS Thuijls, et al. Annals of Surgery, 251 (6), June 2010 PLATETLETS C-REACTIVE PROTEIN WHITE BLOOD CELL

38 Claudin Thuijls, et al. Annals of Surgery, 251 (6), June 2010 Actin filaments myosin Zo-3 Zo-1 Zo-2 occludin claudin JAM Paracellular space

39 Calprotectin Thuijls, et al. Annals of Surgery, 251 (6), June 2010 Released by intestinal neutrophils with intestinal inflammatory damage and can be used as a marker for gut wall inflammation It is resistant to enzymatic degradation, and can be easily measured in feces. NEC No NEC

40 INTESTINAL FATTY ACID BINDING PROTEIN (I- FABP) Thuijls, et al. Annals of Surgery, 251 (6), June 2010 Small, water soluble protein limited to mature enterocytes of small and large intestine. Released into circulation when cell membrane integrity is compromised. Can be measured in urine

41 NEC versus Non NEC Differentiation Thuijls, et al. Annals of Surgery, 251 (6), June 2010 Marker Cutoff Point Sensitivity Specificity LR+ LR- AUC (95%CI) P I-FABP 2.25 pg/mmole creatinine ( ) <0.001 Claudin-3 8OO.8 INT ( ) Calprotectin microgram/gram feces ( ) 0.001

42 PREDICTIVE BIOMARKERS: Who is at greatest risk?

43 Buccal swab or Salivary analyses: Predictive Biomarkers

44 Biomarker Discovery and Validation (Murgas-Tarrazzo, Neonatology, 2013) 3 chosen for validation 37 identified and 20 mapped

45 Discovery Phase spot # Fold case/norma l mass kda/pi mass kda/pi score coverage Protein Name p-value Interleukin-1 receptor antagonist (IL- 1RA) / / / Peroxiredoxin / / Isoform 1 of Alpha-1-antitrypsin / / / Clusterin isoform (apolipoprotein J) / / / Proteosome subunit alpha type / / Gelsolin (isoform 2-cytoplasmic) / / / Cleaved Peroxisomal multifunctional enzyme type / / (3R)-hydroxyacyl-Co A dehydrogenase) Phosphatidylethanolamine-binding protein / / Alpha-2-glycoprotein 1, zinc precursor / / Polymeric immunoglobulin receptor / / cdna FLJ / / / Prolactin-inducible protein / / / Protein-glutamine gammaglutamyltransferase E / / Neutrophil gelatinase-associated lipocalin (lipocalin-2) / / N-acetylglucosamine kinase / / cdna FLJ53019, highly similar to Serpin B / / cdna FLJ54957, highly similar to transketolase / / / Placental protein / / Isoform 1 of heat shock cognate 71 kda protein / / unique peptides

46 Validation Phase Western Blots showed IL-1 RA lower in babies who subsequently developed NEC. ELISA-no difference. Still searching: Other promising biomarkers being evaluated. Lipocalin-2

47 Prevention with Mother s Milk: NEC in Premature Infants (UK) In-Hospital Diet All Cases Confirmed Cases Formulas Only (n=236) 24 (10.2%) 17 (7.2%) Formulas plus Mother s Milk (n=437) 16 (3.7%) 11 (2.5%) Human Milk (n= 253) 11 (4.3%) 3 (1.2%) Lucas & Cole, Lancet 1990;336:

48 Preventative Measures Questionable measures Formula acidification. IgG-IgA. Oral antibiotics. Glucocorticoids. Anticytokine therapy Growth Factors (EGF) Arginine/glutamine Artificial amniotic fluid Pre, pro and postbiotics

49 Routine Use of Probiotics

50 Probiotic-Definition The definition of probiotics as defined by the World Health Organization is "live microorganisms which when administered in adequate amounts confer a health benefit on the host. There are well over 100 types of probiotics, with over 50 Lactobacillus species alone.

51 Food Supplement or Drug? It depends! Health claim usually should be considered a drug. Drugs that are sold by prescription are subjected to rigorous testing. Foods can be sold by anyone and not subjected to rigorous standards.

52 Deshpande, G. Pediatrics, 2010 Meta-Analysis-Death Probiotics significantly reduce mortality in VLBW infants by 41% (from 8.3% down to 3.4%) " NNT 21 Is the result valid and reliable? Can it be generalized?

53 Summary of 2010 Meta Analysis 11 studies evaluated. 10 different probiotic preparations. Risk for NEC and death significantly lower in probiotic group. Sepsis did not differ. Overall evidence indicate that additional placebo controlled trials are unnecessary if a suitable probiotic product is available. Deshpande,G. Pediatrics, May 2010

54

55 Examples of Misadventures and Over-Exuberance High Oxygen/minimal oxygen=retinopathy and increased mortality. 100% oxygen for resuscitation. High dose vitamin K and kernicterus Sulfizoxazole prophylaxis and kernicturus Chloramphenicol and cardiovascular collapse Steroids and cerebral palsy Furosemide and pathologic fractures.

56

57

58

59 Some regulatory concerns Is there a suitable probiotic product with adequate quality control that is approved by the Food and Drug Administration (FDA) (as safe and effective for NEC) currently on the market? To this author s knowledge there is not such a product. Neu, J. Journal of Pediatrics, April 2011

60 Questions Which probiotics actually decrease NEC? Is there really a decrease in mortality and is this causally related to probiotics? Are there populations that might benefit the most? Are there risks (e.g. increased sepsis, long term risks, etc.)?

61 Multicenter Trial of Probiotics in Taiwan Lin, et al PEDIATRICS Vol. 122 No. 4 October 2008, pp

62 Multicenter Trial of Probiotics in Taiwan (750 g) Lin, et al PEDIATRICS Vol. 122 No. 4 October 2008, pp

63 FDA ALERT!! Fatal gastrointestinal mucormycosis in an infant following use of contaminated ABC Dophilus from Solgar Company CDC, FDA, and the Connecticut Departments of Public Health and Consumer Protection, are investigating a fatal case of GI mucormycosis in a premature infant of 29 weeks gestation following the use of a probiotic supplement called ABC Dophilus distributed by Solgar, Inc., Leonia, NJ.

64

65 Probiotic NEC study - sample size calculation NEC incidence Infants per group One-sided Two -sided 5% baseline % baseline Parallel group design One-sided (two-sided) testing α=5%, ß=80% 50% reduction in NEC incidence

66 Largest Studies so far ProPrems---Pediatrics, 2013-powered for late onset sepsis very preterm infants from Australia and New Zealand were randomized. No significant difference in definite late-onset sepsis or all-cause mortality was found. probiotic combination reduced NEC of Bell stage 2 or more (2.0% versus 4.4%; relative risk 0.46, 95% confidence interval 0.23 to 0.93, P =.03; number needed to treat 43, 95% confidence interval 23 to 333). COSTELLO STUDY IN GREAT BRITAIN:NO DIFFERENCES

67 Current Status in U.S. Although the prevalence is not known, many neonatologists have started prescribing probiotics in NICUs for the prevention of NEC. Anecdotally, some of the agents being used are not even probiotics previously studied in preterm neonates. In the United States, there are no probiotics that are licensed or for which there are well developed access schemes for routine use in the prevention of NEC as suggested by one author for their use.

68 Current Status in U.S. There are also no current standards for quality control of a reconstituted product. Good manufacturing practices (GMPs) specifically for use of probiotics as drugs to prevent a specific disease such as NEC are not available.

69 Probiotics: Conclusions and Recommendations So far no product has been licensed. Confirmation of the available results in large, adequately powered, possibly multi-center, well designed RCTs with proven NEC or mortality as primary outcome is required. Abrahamsson TR, Rautava S, Moore AM, Neu J, Sherman PM.J Pediatr Aug;165(2):389-94

70 Take Home Messages NEC is more than one disease. Pathogenesis of classic NEC is multifactorial, but some factors (e.g., GI microbial ecology) may be more important than others. Predictive and diagnostic biomarkers are needed for targeted prevention and therapy. Promising preventative measures may be on the horizon but we need to proceed carefully.