title: Up-regulation of hypoxia-inducible factor 1 alpha and hemodynamic responses following massive small bowel resection.
abstract: OBJECTIVE
  Massive small bowel resection (SBR) results in an adaptive response within the remnant bowel. We have previously shown an immediate reduction in intestinal blood flow and oxygen saturation (sO2) after SBR. We therefore sought to determine the duration of resection-induced intestinal hypoxia and expression of hypoxia-inducible factors (HIFs) following SBR.
  
  
  METHODS
  C57B6 mice were subjected to 50% proximal SBR or a sham procedure. Photoacoustic microscopy (PAM) was used to measure blood flow and sO2 on postoperative days (PODs) 1, 3, and 7. Ileal tissue was harvested 6h postoperatively and on PODs 1 and 2, and HIF1α, HIF2α, and VEGF mRNA expression were assessed via RT-PCR. A p value of less than 0.05 was considered significant.
  
  
  RESULTS
  Following SBR, reduction in intestinal blood flow persists for 24h and is followed with hyperemia by POD 3. The immediate reduction in venous sO2 and increased tissue oxygen utilization continued through POD 7. Enhanced expression of HIF1α was demonstrated 6h following SBR.
  
  
  CONCLUSIONS
  Massive SBR results in an immediate relative hypoxic state within the remnant bowel with early enhanced expression of HIF1α. On POD 7, increased tissue oxygen extraction and elevated blood flow persist in the adapting intestine.
authors.affiliation: Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA.
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Rowland
authors.forename: Junjie
authors.initials: J
authors.lastname: Yao
authors.forename: Lidai
authors.initials: L
authors.lastname: Wang
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Erwin
authors.forename: Konstantin I
authors.initials: KI
authors.lastname: Maslov
authors.forename: Lihong V
authors.initials: LV
authors.lastname: Wang
authors.forename: Brad W
authors.initials: BW
authors.lastname: Warner
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D001783:Blood Flow Velocity; D015536:Down-Regulation; D000860:Hypoxia / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007421:Intestine, Small / Q000098:blood supply / Q000378:metabolism / Q000601:surgery*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008853:Microscopy; D010100:Oxygen / Q000378:metabolism; D061088:Photoacoustic Techniques; D011183:Postoperative Complications / Q000378:metabolism / Q000503:physiopathology; D011184:Postoperative Period; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010100:Oxygen; D042461:Vascular Endothelial Growth Factor A; D000099162:Endothelial PAS Domain-Containing Protein 1; C497443:Hif1a protein, mouse; C467480:vascular endothelial growth factor A, mouse
keywords: Blood flow; HIF1α; Hypoxia-inducible factor; Intestine; Oxygen saturation; Photoacoustic microscopy; Small bowel resection (SBR)