Document Detail


Pathogenesis of neonatal necrotizing enterocolitis: a study of the role of intraluminal pressure, age and bacterial concentration.
MedLine Citation:
PMID:  14551717     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The pathogenesis of neonatal necrotizing enterocolitis (NEC) is unknown. Intestinal dilatation and preferred occurrence of NEC at sites of bacterial overgrowth (colon and ileum) are common findings. The study attempted to produce NEC with increasing intraluminal pressures and bacterial concentrations in two different aged groups of rats. First, 10-cm terminal ileum segments were isolated with intact vascular pedicles in 1-and 3-month-old rats, and a dose of 10(11) E. coli in 1 ml was injected into each segment. Intraluminal pressure was sustained for 1 h at 150, 100, 50 and 0 cmH(2)0, respectively, in four experimental groups ( n=6). The isolated loop was then returned to the abdominal cavity and assessed grossly for NEC after 24 h. Histological examination was performed by a pathologist (KWC) who was blinded to the procedures. Second, the procedure was repeated with doses of 10(8), 10(5) and 0 bacteria/ml ( n=6) at intraluminal pressure of 100 cmH(2)0 in 1-month-old rats. Third, in another experimental group, oxygenation of the pedicled loop was assessed by oximetry as the intraluminal pressure increased and the findings were correlated with aortic blood pressure. The blood pressures (mean+/-SD) for 3- and 1-month-old rats were 110+/-6 and 72+/-4 mmHg, respectively. Hypoxia (<50% oxygen saturation) of the bowel was detected when the intraluminal pressure exceeded the mean blood pressure. The relative incidences of NEC in the bowel with intraluminal pressure above and below mean blood pressure were 100% (6/6) vs. 4% (1/24; P<0.05) in 3-month-old rats, and 100% (12/12) vs. 11% (2/18; P<0.05) in 1-month-old rats. There was no occurrence of NEC in bowel injected with 10(5) E. coli/ml and less at 100 cm intraluminal pressure. Increased intraluminal pressure results in bowel hypoxia and in the presence of adequate bacterial concentration predisposes to the development of NEC. Young age is associated with a lower threshold for increased intraluminal pressure leading to NEC.
Authors:
K L Chan; S P Ng; K W Chan; Y H Wo; P K H Tam
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Publication Detail:
Type:  Journal Article     Date:  2003-10-09
Journal Detail:
Title:  Pediatric surgery international     Volume:  19     ISSN:  0179-0358     ISO Abbreviation:  Pediatr. Surg. Int.     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-11-07     Completed Date:  2004-03-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8609169     Medline TA:  Pediatr Surg Int     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  573-7     Citation Subset:  IM    
Affiliation:
Division of Pediatric Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong SAR, China. klchan@hkucc.hku.hk
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MeSH Terms
Descriptor/Qualifier:
Age Factors
Animals
Enterocolitis, Necrotizing / etiology,  microbiology*,  physiopathology*
Escherichia coli Infections / complications*
Ileum / physiopathology
Models, Animal
Pressure / adverse effects*
Rats
Rats, Sprague-Dawley

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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