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Hepatocyte growth factor (HGF) increases glucagon immunoreactivity in jejunal cells during intestinal adaptation
S52
Pediatric Surgery
RESULTS: The GJ protein connexin-43 was expressed between adjacent IEC-6 cells and in mucosal scrapings. Lucifer yellow but not Rd-dextran passed between adjoining cells, indicating functional gap junctions. Oleamide significantly impaired GJs in enterocytes (communicating cells: control 3 ⫾ 1 vs. 0.5 ⫾ .2, p ⬍ 0.05). Gap junction inhibition prevented migration of IEC-6 cells into a scraped wound (control: 5 m/hr vs. oleamide 0.5 m/hr, p ⬍ 0.05), without affecting viability or proliferation. Strikingly, ileal mucosa from NEC rats showed significantly reduced expression of connexin-43 compared to controls (connexin/actin control:1 ⫾ 0.2 vs. NEC 0.2 ⫾ 0.05, p ⬍ 0.05), implying impaired gap junction function in NEC. CONCLUSIONS: Enterocyte migration requires intercellular communication via gap junctions, which are reduced in NEC. These findings provide insights into the mechanisms leading to impaired mucosal healing in this disease.
Effect of esophageal ligation (EL) on small intestinal (SI) development in a rabbit model of intrauterine growth retardation (IUGR) Christina Cellini MD, Jian Xu MD, Terry L Buchmiller-Crair MD, FACS Weill Cornell Medical College New York, NY INTRODUCTION: Uninterrupted passage of amniotic fluid (AF) through the GI tract appears necessary for normal fetal growth. Previous work suggests that this is related to defective nutrient transport when AF passage is eliminated by EL in normal weight animals. The rabbit provides a naturally occurring model of IUGR based on fetal position within the bicornuate uterus. The effect of in-utero EL on SI development in normal and IUGR fetuses was evaluated. METHODS: Thirteen pregnant rabbits underwent operation on day 24 of their 31-day gestation. Ipsilateral normal and IUGR fetuses underwent EL; contralateral fetuses underwent cervical exploration only, forming 4 study groups (Cont-Nl, Cont-IUGR; EL-Nl, ELIUGR). Fetuses were sacrificed on day 31. The SI was analyzed for: villus height, epithelial cell proliferation by PCNA staining, sodiumglucose cotransporter-1 (SGLT-1) expression by PCR against internal controls and SGLT-1 localization by immunohistochemistry. Statistical analysis was performed using the paired Student’s t-test. RESULTS: Fetal survival was 92%. IUGR fetuses had decreased weight vs. normal (p ⬍ 0.0004) which was further decreased by EL. Villus height and SI epithelial proliferation were significantly decreased in IUGR fetuses in both groups yet not affected by EL. IUGR increased SGLT-1 mRNA production (Cont-IUGR ⫽ 1.3 vs. ContNl ⫽ 1.2; p ⫽ 0.03). EL virtually eliminated villus enterocyte SGLT-1 protein expression in both groups. CONCLUSIONS: AF exclusion by in-utero EL decreased fetal weight and SGLT-1 protein expression. SI villus height and enterocyte proliferation is depressed in IUGR fetuses, but remains independent of AF passage. Exposure of the fetal GI tract to AF appears necessary for proper expression of nutrient transporter proteins.
J Am Coll Surg
Hepatocyte growth factor (HGF) increases glucagon immunoreactivity in jejunal cells during intestinal adaptation Shaheen Timmapuri MD, David Otterburn MD, Marshall Z Schwartz MD, FACS, Hwyda Arafat MD, PhD Thomas Jefferson University Philadelphia, PA INTRODUCTION: The administration of HGF during intestinal adaptation is known to enhance intestinal adaptation. Glucagon has been implicated as a potential mediator of intestinal adaptation. Previous studies have shown that HGF and glucagon synergistically increase the proliferation of hepatocytes. This study was designed to determine if HGF stimulation influenced glucagon expression in the small intestine during intestinal adaptation. METHODS: Adult male Sprague-Dawley rats were randomized to either a 70% massive small bowel resection group (MSBR) or an HGF treated MSBR group (MSBR-HGF). Seven days after surgery HGF was administered intravenously at 150ug/kg/day for 14 days. At day 21 ileal and jejunal mucosa was harvested. The RAE 230A GeneChip and MAS5 software were used to determine alterations in gene expression in the small intestine mucosa. Glucagon immunoreactivity was semiquantified in the ileum and jejunum using rabbit antiglucagon antibody. RESULTS: The MSBR-HGF group had significantly greater protein and DNA content (p ⬍ 0.05) than the MSBR group. However, glucagon gene expression in the MSBR-HGF group was decreased. Immunohistostaining for glucagon in the ileum revealed no difference in intensity between the two groups. However, the MSBR-HGF group demonstrated significantly greater jejunal glucagon immunoreactivity. CONCLUSIONS: Our data suggest that the HGF induced increase in glucagon availability is disassociated from glucagon gene up-regulation. Thus, HGF may not only enhance intestinal adaptation directly, but also indirectly by increasing the “local” availability of other growth factors in the absence of their gene up-regulation.
The role of vasculogenesis in the pathogenesis of intestinal atresia Timothy J Fairbanks MD, Robert Kanard MD, Y Robert Kim MD, Chrissy Lopez BS, Frederic Sala MS, Pierre Del Moral MS, Stijn De Langhe MS, Jacqueline Veltmaat PhD, Saverio Bellusci PhD, Kathryn Anderson MD, FACS, R. Cartland Burns MD, FACS Childrens Hospital Los Angeles Los Angeles, CA INTRODUCTION: Invalidation of the Fibroblast growth factor 10 (Fgf10) pathway results in colonic atresia. Fetal liver kinase (Flk-1), a receptor for vascular endothelial growth factor, is critical for vasculogenesis. The goal of the current study is to evaluate the role of vasculogenesis (via Flk-1 expression), as a pathogenic factor in the colonic atresia caused by the deletion of Fgf10. METHODS: Fgf10⫺/⫺, Fgf10nlacZ/⫹ & Flk-1nlacZ/⫹ mutant mouse strains were crossed, creating mutant embryos with colonic atresia expressing a lacZ reporter gene under to the control of the
Pediatric Surgery
RESULTS: The GJ protein connexin-43 was expressed between adjacent IEC-6 cells and in mucosal scrapings. Lucifer yellow but not Rd-dextran passed between adjoining cells, indicating functional gap junctions. Oleamide significantly impaired GJs in enterocytes (communicating cells: control 3 ⫾ 1 vs. 0.5 ⫾ .2, p ⬍ 0.05). Gap junction inhibition prevented migration of IEC-6 cells into a scraped wound (control: 5 m/hr vs. oleamide 0.5 m/hr, p ⬍ 0.05), without affecting viability or proliferation. Strikingly, ileal mucosa from NEC rats showed significantly reduced expression of connexin-43 compared to controls (connexin/actin control:1 ⫾ 0.2 vs. NEC 0.2 ⫾ 0.05, p ⬍ 0.05), implying impaired gap junction function in NEC. CONCLUSIONS: Enterocyte migration requires intercellular communication via gap junctions, which are reduced in NEC. These findings provide insights into the mechanisms leading to impaired mucosal healing in this disease.
Effect of esophageal ligation (EL) on small intestinal (SI) development in a rabbit model of intrauterine growth retardation (IUGR) Christina Cellini MD, Jian Xu MD, Terry L Buchmiller-Crair MD, FACS Weill Cornell Medical College New York, NY INTRODUCTION: Uninterrupted passage of amniotic fluid (AF) through the GI tract appears necessary for normal fetal growth. Previous work suggests that this is related to defective nutrient transport when AF passage is eliminated by EL in normal weight animals. The rabbit provides a naturally occurring model of IUGR based on fetal position within the bicornuate uterus. The effect of in-utero EL on SI development in normal and IUGR fetuses was evaluated. METHODS: Thirteen pregnant rabbits underwent operation on day 24 of their 31-day gestation. Ipsilateral normal and IUGR fetuses underwent EL; contralateral fetuses underwent cervical exploration only, forming 4 study groups (Cont-Nl, Cont-IUGR; EL-Nl, ELIUGR). Fetuses were sacrificed on day 31. The SI was analyzed for: villus height, epithelial cell proliferation by PCNA staining, sodiumglucose cotransporter-1 (SGLT-1) expression by PCR against internal controls and SGLT-1 localization by immunohistochemistry. Statistical analysis was performed using the paired Student’s t-test. RESULTS: Fetal survival was 92%. IUGR fetuses had decreased weight vs. normal (p ⬍ 0.0004) which was further decreased by EL. Villus height and SI epithelial proliferation were significantly decreased in IUGR fetuses in both groups yet not affected by EL. IUGR increased SGLT-1 mRNA production (Cont-IUGR ⫽ 1.3 vs. ContNl ⫽ 1.2; p ⫽ 0.03). EL virtually eliminated villus enterocyte SGLT-1 protein expression in both groups. CONCLUSIONS: AF exclusion by in-utero EL decreased fetal weight and SGLT-1 protein expression. SI villus height and enterocyte proliferation is depressed in IUGR fetuses, but remains independent of AF passage. Exposure of the fetal GI tract to AF appears necessary for proper expression of nutrient transporter proteins.
J Am Coll Surg
Hepatocyte growth factor (HGF) increases glucagon immunoreactivity in jejunal cells during intestinal adaptation Shaheen Timmapuri MD, David Otterburn MD, Marshall Z Schwartz MD, FACS, Hwyda Arafat MD, PhD Thomas Jefferson University Philadelphia, PA INTRODUCTION: The administration of HGF during intestinal adaptation is known to enhance intestinal adaptation. Glucagon has been implicated as a potential mediator of intestinal adaptation. Previous studies have shown that HGF and glucagon synergistically increase the proliferation of hepatocytes. This study was designed to determine if HGF stimulation influenced glucagon expression in the small intestine during intestinal adaptation. METHODS: Adult male Sprague-Dawley rats were randomized to either a 70% massive small bowel resection group (MSBR) or an HGF treated MSBR group (MSBR-HGF). Seven days after surgery HGF was administered intravenously at 150ug/kg/day for 14 days. At day 21 ileal and jejunal mucosa was harvested. The RAE 230A GeneChip and MAS5 software were used to determine alterations in gene expression in the small intestine mucosa. Glucagon immunoreactivity was semiquantified in the ileum and jejunum using rabbit antiglucagon antibody. RESULTS: The MSBR-HGF group had significantly greater protein and DNA content (p ⬍ 0.05) than the MSBR group. However, glucagon gene expression in the MSBR-HGF group was decreased. Immunohistostaining for glucagon in the ileum revealed no difference in intensity between the two groups. However, the MSBR-HGF group demonstrated significantly greater jejunal glucagon immunoreactivity. CONCLUSIONS: Our data suggest that the HGF induced increase in glucagon availability is disassociated from glucagon gene up-regulation. Thus, HGF may not only enhance intestinal adaptation directly, but also indirectly by increasing the “local” availability of other growth factors in the absence of their gene up-regulation.
The role of vasculogenesis in the pathogenesis of intestinal atresia Timothy J Fairbanks MD, Robert Kanard MD, Y Robert Kim MD, Chrissy Lopez BS, Frederic Sala MS, Pierre Del Moral MS, Stijn De Langhe MS, Jacqueline Veltmaat PhD, Saverio Bellusci PhD, Kathryn Anderson MD, FACS, R. Cartland Burns MD, FACS Childrens Hospital Los Angeles Los Angeles, CA INTRODUCTION: Invalidation of the Fibroblast growth factor 10 (Fgf10) pathway results in colonic atresia. Fetal liver kinase (Flk-1), a receptor for vascular endothelial growth factor, is critical for vasculogenesis. The goal of the current study is to evaluate the role of vasculogenesis (via Flk-1 expression), as a pathogenic factor in the colonic atresia caused by the deletion of Fgf10. METHODS: Fgf10⫺/⫺, Fgf10nlacZ/⫹ & Flk-1nlacZ/⫹ mutant mouse strains were crossed, creating mutant embryos with colonic atresia expressing a lacZ reporter gene under to the control of the