title: Smooth muscle actin as a novel serologic marker of severe intestinal damage in rat intestinal ischemia-reperfusion and human necrotising enterocolitis.
abstract: BACKGROUND
  Despite emergence of markers of intestinal mucosal damage such as intestinal fatty-acid binding protein (i-FABP), there are no specific markers of damage extending into the muscle layers. We hypothesized that smooth muscle actin (SMA) released from the intestinal muscularis would be detectable in plasma after severe intestinal injury.
  
  
  METHODS
  Serial blood samples were collected from rats (n = 10) undergoing intestinal ischemia-reperfusion injury (IRI) and controls (n = 5). Additionally, admission and/or preoperative plasma samples were collected from twelve neonates with necrotizing enterocolitis (NEC), and five age- and weight-matched controls. Plasma ileal fatty-acid binding protein (rat) or i-FABP (human) were measured by enzyme-linked immunosorbent assay, and plasma SMA was detected by western blotting.
  
  
  RESULTS
  Plasma ileal fatty-acid binding protein was low in both the control group and IRI at baseline, but became rapidly elevated in the IRI group even during ischemia. SMA was detected in reperfusion plasma samples of all IRI rats, but in none of the control samples. Plasma i-FABP was higher in infants with NEC than age- and weight-matched controls. Although i-FABP was higher in infants with severe surgical disease compared with focal disease, there was no difference between the operative and nonoperative groups. SMA was detected in the plasma of all four neonates with severe surgical NEC, but not in those with focal disease or those who were successfully conservatively managed.
  
  
  CONCLUSIONS
  SMA is detectable in plasma after severe intestinal injury and maybe a clinically useful maker of intestinal muscle damage.
authors.affiliation: Department of Surgery, UCL Institute of Child Health, London, UK. Electronic address: nevennett@mac.com.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Evennett
authors.affiliation: Department of Surgery, UCL Institute of Child Health, London, UK.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Cerigioni
authors.affiliation: Department of Surgery, UCL Institute of Child Health, London, UK.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Hall
authors.affiliation: Department of Surgery, UCL Institute of Child Health, London, UK.
authors.forename: Agostino
authors.initials: A
authors.lastname: Pierro
authors.affiliation: Department of Surgery, UCL Institute of Child Health, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Eaton
mesh_terms: D000199:Actins / Q000097:blood*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D020345:Enterocolitis, Necrotizing / Q000097:blood / Q000175:diagnosis*; D050556:Fatty Acid-Binding Proteins / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D007422:Intestines / Q000098:blood supply*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000097:blood / Q000175:diagnosis*
chemical_list: D000199:Actins; D015415:Biomarkers; D050556:Fatty Acid-Binding Proteins; C541116:ACTA2 protein, human; C498862:Acta2 protein, rat
keywords: Diagnostic marker; Intestinal ischemia; Necrotizing enterocolitis; Serum marker; Smooth muscle actin; Transmural intestinal necrosis