Acute remote ischemic preconditioning on a rat cremasteric muscle flap model

Abstract

A previous study showed, in a rat adipocutaneous flap model, that acute ischemic preconditioning (IP) can be achieved not only by preclamping of the flap pedicle, but also by a brief extremity ischemia prior to flap ischemia. The purpose of this study was to determine whether remote IP is also effective in other tissues such as muscle flaps. Twenty male Wistar rats were divided into three experimental groups. The rat cremaster flap in vivo microscopy model was used for assessment of ischemia/reperfusion injury. In the control group (CG, n = 8), a 2-hr flap ischemia was induced after preparation of the cremaster muscle. In the "classic" IP group (cIP, n = 6), a brief flap ischemia of 10 min was induced by preclamping the pedicle, followed by 30 min of reperfusion. A 10-min ischemia of the contralateral hindlimb was induced in the remote IP group (rIP, n = 6). The limb was then reperfused for 30 min. Flap ischemia and the further experiment were performed as in the CG. In vivo microscopy was performed after 1 hr of flap reperfusion in each animal. A significantly higher red blood cell velocity in the first-order arterioles and capillaries, a higher capillary flow, and a decreased number of leukocytes adhering to the endothelium of the postcapillary venules were observed in both preconditioned groups by comparison to the control group (P < 0.05). The differences within the preconditioned groups were not significant for these parameters. Our data show that ischemic preconditioning and improvement of flap microcirculation can be achieved not only by preclamping of the flap pedicle, but also by induction of an ischemia/reperfusion event in a body area distant from the flap prior to elevation. These findings indicate that remote IP is a systemic phenomenon, leading to an enhancement of flap survival. Our data suggest that remote IP could be performed simultaneously with flap elevation in the clinical setting without prolongation of the operation and without invasive means.

Acute remote ischemic preconditioning II: The role of nitric oxide

“…Previous studies from our laboratory and part one of this study demonstrated in rat models that ischemic preconditioning, enhancement of flap survival, and improvement of flap microcirculation following ischemia can be achieved not only by preclamping of the flap pedicle, but also by induction of an ischemia/reperfusion event in a body area distant from the flap (hindlimb ischemia) prior to elevation. 1,2 These findings indicate that ischemic preconditioning of flaps is a systemic phenomenon, and not only a local reaction in the flap itself.…”

“…Averages of 60.4 (20.2)``stickers'' and 18.4 (10.4)`r ollers'' (for definitions, see part one of this study 2 ) per mm venule length were observed in the control group. The number of stickers was 15.8 (6.1) in group NO, 65.6 (19.9) in group LN + P, 41.1 (12.4) in group LN + T, and 66.5 (22.7) in group LN (Fig.…”

“…The data show that NO plays an important role in the mechanism of both acute``classic'' as well as acute remote IP, since the administration of a NOdonor previous to ischemia simulates the effect of IP, whereas the nonspecific blocking of NO synthesis by L-NAME abolishes the protective effect of flap preconditioning. In a previous study 1 and in part one of this study, 2 it was demonstrated that ischemic preconditioning (IP), enhancement of flap survival, and improvement of flap microcirculation can be achieved, not only by preclamping the flap pedicle, but also by induction of an ischemia/reperfusion event in a body area distant from the flap prior to flap elevation. A brief tourniquet ischemia of a rat hindlimb before flap ischemia demonstrated the same protective effect as preclamping in a rat model.…”

Remote ischaemic preconditioning of the hind limb reduces experimental liver warm ischaemia–reperfusion injury

“…RIPC of the limb in humans 8 and animals 9 reduces IRI to the heart, lungs and other organs 10 . A putative role for nitric oxide has been suggested 11 .…”

Protection of organs other than the heart by remote ischemic conditioning

“…This is likely to be caused by prolonged post-operative flap ischemia when the flap is exposed to during the surgery. Küntscher et al [79][80][81] were the first to demonstrate that hindlimb RIC (10 min clamping of femoral artery) could protect muscle flaps against IRI. Whether, this RIC is beneficial in the clinical setting of plastic surgery is currently being tested in patients undergoing skin flap transplantation to the anterolateral thigh (ClinicalTrials.gov identifier: NCT01235286).…”