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Item Human Mesenchymal Stromal Cells Decrease Mortality Following Intestinal Ischemia and Reperfusion Injury(Elsevier, 2015-11) Markel, Troy A.; Crafts, Trevor D.; Jensen, Amanda R.; Hunsberger, E. Bailey; Department of Surgery, IU School of MedicineBackground Cellular therapy is a novel treatment option for intestinal ischemia. Bone marrow–derived mesenchymal stromal cells (BMSCs) have previously been shown to abate the damage caused by intestinal ischemia/reperfusion (I/R) injury. We therefore hypothesized that (1) human BMSCs (hBMSCs) would produce more beneficial growth factors and lower levels of proinflammatory mediators compared to differentiated cells, (2) direct application of hBMSCs to ischemic intestine would decrease mortality after injury, and (3) decreased mortality would be associated with an altered intestinal and hepatic inflammatory response. Methods Adult hBMSCs and keratinocytes were cultured on polystyrene flasks. For in vitro experiments, cells were exposed to tumor necrosis factor, lipopolysaccharides, or 2% oxygen for 24 h. Supernatants were then analyzed for growth factors and chemokines by multiplex assay. For in vivo experiments, 8- to 12-wk-old male C57Bl6J mice were anesthetized and underwent a midline laparotomy. Experimental groups were exposed to temporary superior mesenteric artery occlusion for 60 min. Immediately after ischemia, 2 × 106 hBMSCs or keratinocytes in phosphate-buffered saline were placed into the peritoneal cavity. Animals were then closed and allowed to recover for 6 h (molecular/histologic analysis) or 7 d (survival analysis). After 6-h reperfusion, animals were euthanized. Intestines and livers were harvested and analyzed for inflammatory chemokines, growth factors, and histologic changes. Results hBMSCs expressed higher levels of human interleukin (IL) 6, IL-8, vascular endothelial growth factor (VEGF), and epidermal growth factor and lower levels of IL-1, IL-3, IL-7, and granulocyte-monocyte colony-stimulating factor after stimulation. In vivo, I/R resulted in significant mortality (70% mortality), whereas application of hBMSCs after ischemia decreased mortality to 10% in a dose-dependent fashion (P = 0.004). Keratinocyte therapy offered no improvements in mortality above I/R. Histologic profiles were equivalent between ischemic groups, regardless of the application of hBMSCs or keratinocytes. Cellular therapy yielded significantly decreased murine intestinal levels of soluble activin receptor-like kinase 1, betacellulin, and endothelin, whereas increasing levels of eotaxin, monokine induced by gamma interferon (MIG), monocyte chemoattractant protein 1, IL-6, granulocyte colony-stimulating factor (G-CSF), and interferon gamma-induced protein 10 (IP-10) from ischemia were appreciated. hBMSC therapy yielded significantly higher expression of murine intestinal VEGF and lower levels of intestinal MIG compared to keratinocyte therapy. Application of hBMSCs after ischemia yielded significantly lower murine levels of hepatic MIG, IP-10, and G-CSF compared to keratinocyte therapy. Conclusions Human BMSCs produce multiple beneficial growth factors. Direct application of hBMSCs to the peritoneal cavity after intestinal I/R decreased mortality by 60%. Improved outcomes with hBMSC therapy were not associated with improved histologic profiles in this model. hBMSC therapy was associated with higher VEGF in intestines and lower levels of proinflammtory MIG, IP-10, and G-CSF in liver tissue after ischemia, suggesting that reperfusion with hBMSC therapy may alter survival by modulating the systemic inflammatory response to ischemia.Item Mesenchymal Stromal Cell Therapy for the Treatment of Intestinal Ischemia: Defining the Optimal Cell Isolate for Maximum Therapeutic Benefit(Elsevier, 2016-12) Doster, Dominique L.; Jensen, Amanda R.; Khaneki, Sina; Markel, Troy A.; Surgery, School of MedicineIntestinal ischemia is a devastating intraabdominal emergency that often necessitates surgical intervention. Mortality rates can be high, and patients who survive often have significant long-term morbidity. The implementation of traditional medical therapies to prevent or treat intestinal ischemia have been sparse over the last decade, and therefore, the use of novel therapies are becoming more prevalent. Cellular therapy using mesenchymal stromal cells is one such treatment modality that is attracting noteworthy attention in the scientific community. Several groups have seen benefit with cellular therapy, but the optimal cell line has not been identified. The purpose of this review is to: 1) Review the mechanism of intestinal ischemia and reperfusion injury, 2) Identify the mechanisms of how cellular therapy may be therapeutic for this disease, and 3) Compare various MSC tissue sources to maximize potential therapeutic efficacy in the treatment of intestinal I/R diseases.Item Stem Cell Therapy and Hydrogen Sulfide: Conventional or Nonconventional Mechanisms of Action?(Wolters Kluwer, 2019) Jensen, Amanda R.; Drucker, Natalie A.; Olson, Ken R.; Markel, Troy A.; Surgery, School of MedicinePurpose: Hydrogen sulfide (H2S) has many beneficial biological properties, including the ability to promote vasodilation. It has been shown to be released from stem cells and increased by hypoxia. Therefore, H2S may be an important paracrine factor in stem cell mediated intestinal protection. We hypothesized that hydrogen sulfide created through conventional pathways would be a critical component of stem cell mediated intestinal protection following ischemic injury. Methods: Human bone marrow derived mesenchymal stem cells (BMSCs) were transfected with negative control siRNA (Scramble), or with siRNA to CBS, MPST, or CTH. Knockdown was confirmed with PCR and hydrogen sulfide gas assessed with AzMC fluorophore. Eight week old male mice then underwent intestinal ischemia for 60 mins, after which time, perfusion was restored. BMSCs from each of the above groups were then placed into the mouse abdominal cavity prior to final closure. After 24 hours, mice were reanesthetized and mesenteric perfusion was assessed by Laser Doppler Imaging (LDI). Animals were then sacrificed and intestines excised, placed in formalin, paraffin embedded, and stained with H & E. Intestines were then scored with a common mucosal injury grading scale. Results: PCR confirmed knockdown of conventional H2S producing enzymes (CBS, MPST, CTH). Hydrogen sulfide gas was decreased in MPST and CTH transfected cells in normoxic conditions but was not decreased compared to scramble in any of the transfected groups in hypoxic conditions. BMSCs promoted increased mesenteric perfusion at 24 hours post-ischemia compared to vehicle. Transfected stem cells provided equivalent protection. Histologic injury was improved with BMSCs compared to vehicle. CBS, MPST, and CTH knockdown cell lines did not have any worse histological injury compared to Scramble. Conclusion: Knocking down conventional H2S producing enzymes only impacted gas production in normoxic conditions. When cells were transfected in hypoxic conditions, as would be expected in the ischemic intestines, hydrogen sulfide gas was not depressed. These data, along with unchanged perfusion and histological injury parameters with conventional enzyme knockdown would indicate that alternative H2S production pathways may be initiated during hypoxic and/or ischemic events.