Bifidobacterium bifidum in a rat model of necrotizing enterocolitis: antimicrobial peptide and protein responses.
BACKGROUND
Necrotizing enterocolitis (NEC) is a devastating disease of premature infants. Probiotics decrease the risk of NEC in clinical and experimental studies. Antimicrobial peptides protect the gut against noxious microbes and shape the commensal microbiota, but their role in NEC remains unclear.


METHODS
To investigate the expression of antimicrobial peptides in experimental NEC and the impact of probiotics on their expression, premature rats were divided into three groups: dam fed (DF), hand fed with formula (FF), or hand fed with formula containing Bifidobacterium bifidum (FF + BIF). All groups were exposed to asphyxia and cold stress.


RESULTS
Like in human ontogeny, the rat pup has low expression of Paneth cell antimicrobials, which increases rapidly during normal development. The expression of lysozyme, secretory phospholipase A(2) (sPLA(2)), pancreatic-associated proteins 1 and 3 mRNA was elevated in the FF group with a high incidence of NEC, as compared with the DF and FF + BIF groups where the disease was attenuated.


CONCLUSIONS
We conclude that induction of antimicrobial peptides occurs in experimental NEC similar to that reported in human disease and is attenuated when disease is averted by probiotic B. bifidum. The induction of antimicrobial peptides is likely an adaptive mucosal response that is often not sufficient to prevent disease in the premature gut.
Department of Pediatrics, University of California-Davis, Sacramento, California, USA. mark.underwood@ucdmc.ucdavis.edu
Mark A
MA
Underwood
Anchasa
A
Kananurak
Christine F
CF
Coursodon
Camille K
CK
Adkins-Reick
Hiutung
H
Chu
Stephen H
SH
Bennett
Jan
J
Wehkamp
Patricia A
PA
Castillo
Brian C
BC
Leonard
Daniel J
DJ
Tancredi
Michael P
MP
Sherman
Bohuslav
B
Dvorak
Charles L
CL
Bevins
D000818:Animals; D000831:Animals, Newborn; D000890:Anti-Infective Agents; D001483:Base Sequence; D001644:Bifidobacterium; D017931:DNA Primers; D004195:Disease Models, Animal; D020345:Enterocolitis, Necrotizing / Q000378:metabolism / Q000382:microbiology* / Q000628:therapy; D015870:Gene Expression; D007150:Immunohistochemistry; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D019936:Probiotics; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000890:Anti-Infective Agents; D017931:DNA Primers; D010455:Peptides; D011506:Proteins