Effects of the addition of endotoxin during perfusion of isolated forelimbs of equine cadavers

Abstract

In the blood-perfused isolated forelimbs of equine cadavers, exposure to LPS led to significant changes in the laminar tissue as well as to metabolic changes. Therefore, endotoxin should be considered as a causative factor for laminitis and not merely as a risk factor.

Extracorporeal perfusion of isolated organs of large animals – Bridging the gap between in vitro and in vivo studies

“…While few studies have used live animals, the justification to induce such a painful condition in live animals may be challenged. The sample sizes required for scientific validity and achieved in studies utilizing organ perfusion methods (e.g., n = 10 (Patan-Zugaj et al, 2012), n = 14 ) would certainly not have been justifiable in vivo.…”

“…In veterinary science, isolated limb perfusion (ILP) has facilitated new insights, e.g., into the clinical picture of laminitis (Wüstenberg, 2006;Patan-Zugaj et al, 2012, a severely debilitating, painful and potentially life-threatening equine and bovine disease. Due to its significant impact on animal well-being and the complexity of potential causative agents and risk factors, continued research efforts are still needed.…”

“…Again, these values are tissue and mass dependent and cannot be seen as absolute references. Both groups report physiological lactate levels, even if an increase of lactate levels within the physiological range was noted over the course of the experiments (Friebe et al, 2013a,b;Patan et al, 2009;Patan-Zugaj et al, 2012. In contrast, lactate levels were (constantly) elevated in the venous perfusate in porcine isolated limb perfusions (up to 105 mg/dl (Wagner et al, 2003), mean maximum value 19.59 mmol/l (Constantinescu et al, 2011)) likely due to the higher metabolic demands of a greater amount of included soft tissues.…”

“…Indeed normothermia is pursued in almost all scientific implementations of the methodology (Kietzmann et al, 1993;Patan-Zugaj et al, 2012). For studies with a physiological, pharmacokinetic or pharmacologic focus (Roets et al, 1979b;Bäumer et al, 2002;Friebe et al, 2013b), the use of hypothermia would seem contra-indicated.…”

“…As indicated above, this approach improves tissue oxygenation despite the reduced concentration of erythrocytes (Dittrich et al, 2000). Reported diluents have been cell free solutions (Domingo-Pech et al, 1991;Wagner et al, 2003;Erasmus et al, 2006;Friebe et al, 2013b) or autologous plasma (Patan et al, 2009;Patan-Zugaj et al, 2012, which comes with the added benefit of increasing oncotic pressure. As cell free solutions are associated with low oncotic pressure, resulting in edema formation and weight gain, adding plasma expanders such as plasma proteins (Verbeke et al, 1968;Roets et al, 1974;Patan et al, 2009) and purified albumin (Rehfeld et al, 1982;Barthel et al, 1989;Riviere et al, 1989;Brunicardi et al, 2001) perfused specimens thus reflects the degree of ischemia/reperfusion injury (Petrasek et al, 1994;Adham et al, 1997) and the integrity of the microvasculature (Müller et al, 2013).…”