In vitro and in vivo responses of mucosa from the large colon of horses to ischemia and reperfusion

Graham, Ann; Grosche, Astrid; Morton, Alison J.; Polyak, Maximilian M. R.; Freeman, David E.

doi:10.2460/ajvr.72.7.982

Cited by 13 publications

(64 citation statements)

References 40 publications

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“…3) were similar to those recorded in other models of combined arterial and venous occlusion and mural compression (Reeves et al 1990). At 1 hour ischemia, minor histological alterations of the colonic mucosa were evident, with further progression after 2 hour ischemia , Graham et al 2011, Grosche et al 2011, 2012. Moderate hemorrhage into the lamina propria progressed over time during ischemia accompanied by profound interstitial and epithelial cell edema and increased interstitium-crypt ratio.…”

Section: Morphological Changessupporting

confidence: 81%

“…One hour of ischemia induced experimentally in the colon of horses caused mild injury that should have allowed some expression of reperfusion injury over the next 4 hours (Graham et al 2011). When transepithelial resistance (TER) and mannitol permeability of the mucosa was measured in Ussing chambers, the reperfused tissues performed significantly better than ischemic tissues and as well as the control tissues (Figs.…”

Section: Functional Changesmentioning

confidence: 99%

“…Several studies on equine large colonic I/R failed to detect reperfusion injury (Snyder et al 1988, Reeves et al 1990, Wilkins et al 1994, Dabareiner et al 2001, Grosche et al 2011). …”

Section: Reperfusionmentioning

confidence: 99%

“…In our laboratory at the University of Florida, we studied I/R in the equine pelvic flexure with horses anesthetized and then euthanatized after all tissue samples are collected (Graham et al 2011). Colonic mucosa was harvested after various periods of ischemia and reperfusion and examined by histological methods and for in vitro permeability changes in Ussing chambers (Matjyaszek et al 2009, Graham et al 2011.…”

Section: Recent Research On I/r In Equine Colonmentioning

confidence: 99%

“…Colonic mucosa was harvested after various periods of ischemia and reperfusion and examined by histological methods and for in vitro permeability changes in Ussing chambers (Matjyaszek et al 2009, Graham et al 2011. One group of horses was allowed to recover from anesthesia when blood flow was restored to ischemic colon, and and these horses were reanesthetized at 18 hours after reperfusion started.…”

Section: Recent Research On I/r In Equine Colonmentioning

confidence: 99%

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Ischemia in equine intestine – mechanisms of injury and methods of treatment

Freeman¹,

Grosche²

2012

PHK

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SummaryThe importance of reperfusion injury in equine intestine is controversial and unclear. Large colon volvulus and small intestinal strangulation are the most devastating causes of intestinal ischemia in horses and result in severe mucosal damage, barrier dysfunction, endotoxic shock and death. Although essential for tissue recovery, reperfusion after these types of ischemia could exacerbate intestinal injury. Responses to ischemia and reperfusion (I/R) involve a series of synchronized biochemical, cellular and structural changes characterized by generation of reactive oxygen metabolites, activation of immune cells, and epithelial cell degeneration and death. The intensity of neutrophil activation and influx is central to the process of reperfusion injury and the associated inflammatory events. The classic paradigm of reperfusion injury is best displayed after the segmental hypoperfusion or low-flow ischemia model, in which arterial inflow is adjusted to 20% of normal baseline flow, and then allowed to return to normal or greater values during reperfusion. In such cases, injury during the ischemic phase is mild, compared with the reperfusion injury that follows. Although there is some evidence of reperfusion injury in equine colon and jejunum after low-flow ischemia, attempts to ameliorate this by pharmacologic means have met with only moderate success. A multimodal approach, using solutions designed to improve survival in transplanted organs, seems to hold the greatest promise, although these have not been embraced in the clinical setting. Expense and difficulties in delivery are the two most serious limitations. Recent studies to assess the effect of colonic I/R on equine pelvic flexure involved a complete ischemia model that was similar to the clinical lesion, and for periods of 1 to 2 hours of ischemia followed by 30 minutes, 4 hours, or 18 hours of reperfusion. Ischemia caused degeneration and detachment of epithelial cells, early apoptosis, and opening of tight junctions (TJs), all of which decreased transepithelial resistance (TER) and increased mannitol flux when the tissues were studied in vitro. Autophagy was a prominent feature in epithelial cells after 1 hour of ischemia. Reperfusion was characterized by apoptosis, epithelial regeneration, and closure of TJs with improved TER and reduced mannitol leakage. Neutrophils infiltrated colonic mucosa during reperfusion, and macrophages, mast cells and eosinophils were activated during I/R. Equine colonic mucosa subjected to ischemia can repair rapidly and regain barrier integrity during reperfusion, despite intense mucosal inflammation. Recently, attention has focused on inflammation induced by intestinal handling and on remote organ responses to intestinal injury, both of which could be highly relevent to postoperative management of horses that undergo colic surgery. The use of lidocaine in a continuous rate infusion is a popular approach to ameliorate the intestinal inflammatory response after colic surgery, although there is no evidence that it has a...

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Section: Morphological Changessupporting

confidence: 81%

Section: Functional Changesmentioning

confidence: 99%

“…Several studies on equine large colonic I/R failed to detect reperfusion injury (Snyder et al 1988, Reeves et al 1990, Wilkins et al 1994, Dabareiner et al 2001, Grosche et al 2011). …”

Section: Reperfusionmentioning

confidence: 99%

Section: Recent Research On I/r In Equine Colonmentioning

confidence: 99%

Section: Recent Research On I/r In Equine Colonmentioning

confidence: 99%

See 3 more Smart Citations