Lymphatic diversion prevents myocardial edema following mesenteric ischemia/reperfusion.
OBJECTIVE
Mesenteric ischemia/reperfusion (I/R) is associated with cardiac dysfunction. Mesenteric lymph primes polymorphonuclear leukocytes (PMNs) for increased superoxide release following I/R. We hypothesized that mesenteric I/R causes myocardial edema resulting in myocardial dysfunction, and that diverting mesenteric lymph would preserve myocardial function.


METHODS
Two canine groups were studied: lymphatic diversion (LD) and no lymphatic diversion (No LD). Preload recruitable stroke work, +/-dp/dt(max), isovolumic relaxation (tau), cardiac output, and myocardial water content (MWC) were determined. I/R consisted of 60 min of ischemia followed by 180 min of reperfusion. Myocardial myeloperoxidase (MPO) was measured as an index of PMN leukosequestration. In addition, mesenteric lymph harvested after I/R was infused into normal canines and all variables measured.


RESULTS
MWC increased from baseline in No LD. Tau and -dp/dt(max) were significantly affected in No LD, but not in LD. After mesenteric I/R, mesenteric lymph primed PMNs for increased superoxide production. Lymph diversion resulted in significantly lower myocardial MPO. With reinfusion of I/R lymph, MWC and tau increased. MPO was also increased post I/R mesenteric lymph reinfusion.


CONCLUSIONS
Our data indicate that myocardial dysfunction after mesenteric I/R is due to lymph-induced, PMN-mediated microvascular alterations and myocardial edema.
Cox
Charles S
CS
Center for Microvascular and Lymphatic Studies, Department of Surgery, University of Texas--Houston Medical School, Houston, Texas, USA.
Fischer
Uwe M
UM
Allen
Steven J
SJ
Laine
Glen A
GA
D000818:Animals; D004285:Dogs; D004489:Edema, Cardiac / Q000517:prevention & control*; D006334:Heart Function Tests; D008196:Lymph / Q000502:physiology*; D017202:Myocardial Ischemia / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009504:Neutrophils; D009195:Peroxidase / Q000032:analysis; D013152:Splanchnic Circulation; D013481:Superoxides / Q000378:metabolism; D014867:Water / Q000032:analysis
D014867:Water; D013481:Superoxides; D009195:Peroxidase