Enhanced Vascular Collateralization Through the Pancreaticoduodenal Arcade Secondary to Median Arcuate Ligament Compression of the Celiac Axis in the Setting of Pancreatic Body Adenocarcinoma: The Ideal Scenario for the Modified Appleby Procedure

Background: A modified Appleby procedure for pancreatic body tumors relies upon collateral vessels maintaining blood flow to the proper hepatic artery (PHA) through the pancreaticoduodenal arcade (PDA) off of the superior mesenteric artery (SMA). Compression of the celiac axis by the median arcuate ligament (MAL) promotes the expansion of collateral vessels without preoperative intervention. Case Presentation: A 51-year-old male with asymptomatic compression of the celiac artery presented with new onset insulin-dependent diabetes mellitus. He underwent imaging that demonstrated a locally advanced pancreatic body tumor that encased the superior mesenteric vein and portal vein confluence and involved the common hepatic artery. He had an adequate response to neoadjuvant FOLFIRINOX chemotherapy and underwent an uncomplicated modified Appleby procedure with a margin negative resection. Hepatic blood flow was adequate through the PHA as a result of collateralization of blood flow through the PDA off the SMA. The enhanced collateralization appeared to have occurred secondary to compression of the celiac axis by the MAL. Conclusions: Herein we present a unique case in which improved collateral blood flow through the PDA and the gastroduodenal artery to the PHA occurred due to celiac artery compression by the MAL. This vascular anomaly fortuitously improved the ability to achieve an R0 resection of a locally advanced pancreatic adenocarcinoma of the body of the pancreas by a modified Appleby procedure

Vascular Endothelial Growth Factor (VEGF) Bioavailability Regulates Angiogenesis and Intestinal Stem and Progenitor Cell Proliferation during Postnatal Small Intestinal Development.

BACKGROUND:Vascular endothelial growth factor (VEGF) is a highly conserved, master regulatory molecule required for endothelial cell proliferation, organization, migration and branching morphogenesis. Podocoryne carnea and drosophila, which lack endothelial cells and a vascular system, express VEGF homologs, indicating potential roles beyond angiogenesis and vasculogenesis. The role of VEGF in the development and homeostasis of the postnatal small intestine is unknown. We hypothesized regulating VEGF bioavailability in the postnatal small intestine would exhibit effects beyond the vasculature and influence epithelial cell stem/progenitor populations. METHODS:VEGF mutant mice were created that overexpressed VEGF in the brush border of epithelium via the villin promotor following doxycycline treatment. To decrease VEGF bioavailability, sFlt-1 mutant mice were generated that overexpressed the soluble VEGF receptor sFlt-1 upon doxycycline administration in the intestinal epithelium. Mice were analyzed after 21 days of doxycycline administration. RESULTS:Increased VEGF expression was confirmed by RT-qPCR and ELISA in the intestine of the VEGF mutants compared to littermates. The VEGF mutant duodenum demonstrated increased angiogenesis and vascular leak as compared to littermate controls. The VEGF mutant duodenum revealed taller villi and increased Ki-67-positive cells in the transit-amplifying zone with reduced Lgr5 expression. The duodenum of sFlt-1 mutants revealed shorter villi and longer crypts with reduced proliferation in the transit-amplifying zone, reduced expression of Dll1, Bmp4 and VE-cadherin, and increased expression of Sox9 and EphB2. CONCLUSIONS:Manipulating VEGF bioavailability leads to profound effects on not only the intestinal vasculature, but epithelial stem and progenitor cells in the intestinal crypt. Elucidation of the crosstalk between VEGF signaling in the vasculature, mesenchyme and epithelial stem/progenitor cell populations may direct future cell therapies for intestinal dysfunction or disease

VEGF overexpression in OU culture increased OU size and altered stem/progenitor cell gene expression.

<p>(A) The diameter of VEGF mutant OU were measured every other day during a 10-day culture. The diameter of all OU increased over time; however, VEGF mutant OU treated with doxycycline were larger on day 5 compared to controls (*p = 0.04). N = 25 OU per well, 6 wells; Error bars = SEM. (B) VEGF mutant OU exposed to doxycycline demonstrated significant increase in serum VEGF levels over 5 days in culture (*p<0.05). N = 3; Error bars = SEM. (C) Significant increase in Bmi1 and Atoh1 expression and decrease in EphB2 expression was observed in doxycycline-treated VEGF OU compared to controls at 5 days (*p<0.05). N = 3; Error bars = STDEV.</p