Role of the plasma cascade systems in ischemia/reperfusion injury of bone

Abstract

Ischemia/reperfusion (I/R) injury has been extensively studied in organs such as heart, brain, liver, kidney, and lung. As a vascularized organ, bone is known to be susceptible to I/R injury too, but the respective mechanisms are not well understood to date. We therefore hypothesized that, similar to other organs, plasma cascade-induced inflammation also plays a role in bone I/R injury. Reperfusion injury in rat tibia was induced by unilateral clamping of the femoral artery and additional use of a tourniquet, while keeping the femoral vein patent to prevent venous congestion. Rats were subjected to 4h ischemia and 24h reperfusion. Deposition of complement fragment C3b/c and fibrin as well as expression of tissue factor (TF), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), and E-selectin was detected by immunohistochemistry. In plasma, the levels of high mobility group box1 (HMGB1) were measured by ELISA. The total level of complement in serum was assessed by the CH50 test. Our results show that deposition of C3b/c was significantly increased with respect to healthy controls in cortical bone as well as in marrow of reperfused limbs. C3b/c deposition was also increased in cortical bone, but not in bone marrow, of contralateral limbs. Deposition of fibrin, as well as expression of PAI-1, was significantly increased in bone after ischemia and reperfusion, whereas expression of tPA was reduced. These differences were most prominent in vessels of bone, both in marrow and cortical bone, and both in reperfused and contralateral limbs. However, PAI-1, was only increased in vessels of reperfused cortical bone and there were no significant changes in expression of E-selectin. With respect to solid bone tissue, a significant increase of C3b/c and fibrin deposition was shown in osteocytes, and for fibrin also in the bone matrix, in both contralateral and reperfused cortical bone compared with normal healthy controls. A slight expression of TF was visible in osteocytes of the normal healthy control group, while TF was not present in the experimental groups. Moreover, CH50 values in serum decreased over time and HMGB1 was significantly increased in plasma of animals at the end of reperfusion. We conclude that ischemia and reperfusion of bone leads to activation of the complement and coagulation systems and a downregulation of the fibrinolytic cascade. In the acute phase, a vascular inflammation induced by activation of the plasma cascade systems also occurs in the bone. This is similar to I/R injury of other vascularized organs and tissues.

High‐Mobility Group Box‐1 and Liver Disease

“…HMGB1 has been implicated in I/R injury, (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) sepsis, 23,28-32 and APAP-induced liver injury. (23,(33)(34)(35)(36)(37)(38)(39)(40) i/R In I/R injury, organ damage occurs due to the return of oxygen to a previously hypoxic tissue.…”

“…HMGB1 was originally discovered as a nuclear protein; however, when it is passively released or actively secreted after injury or cell stimulation, HMGB1 meets all the criteria of a damage-associated molecular pattern (DAMP) and works as a necrosis signal for the immune system through cell-surface receptors. (12)(13)(14) In this latter role, HMGB1 acts as a proinflammatory cytokine that contributes to multiple injuries, including those from the liver, such as warm and cold ischemia/reperfusion (I/R) injury, (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) sepsis, (23,(28)(29)(30)(31)(32) acetaminophen (APAP) intoxication, (23,(33)(34)(35)(36)(37)(38)(39)(40) alcoholic liver disease (ALD), (41)(42)(43) fibrosis, (44)(45)(46)(47)(48)(49) nonalcoholic steatohepatitis (NASH), (50)(51)(52) and hepatocellular carcinoma (HCC). (53)…”

“…HMGB1 was originally discovered as a nuclear protein; however, when it is passively released or actively secreted after injury or cell stimulation, HMGB1 meets all the criteria of a damage‐associated molecular pattern (DAMP) and works as a necrosis signal for the immune system through cell‐surface receptors . In this latter role, HMGB1 acts as a proinflammatory cytokine that contributes to multiple injuries, including those from the liver, such as warm and cold ischemia/reperfusion (I/R) injury, sepsis, acetaminophen (APAP) intoxication, alcoholic liver disease (ALD), fibrosis, nonalcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC) . By binding cell‐surface receptors on immune cells, HMGB1 activates intracellular signaling pathways that regulate immune cell function, including chemotaxis and cytokine production .…”

Effects of C1 inhibitor on endothelial cell activation in a rat hind limb ischemia-reperfusion injury model

“…For normal rats (control group), we observed a very small standard derivation (<1%) in our earlier study. 20 We therefore decided to limit this group to four to keep the number of animals to a minimum. Two more rats were included in the experimental group 2 and the control group 2 because of problems with blood sampling at some time points.…”

Microcirculatory consequences of limb ischemia/reperfusion in ovariectomized rats treated with zoledronic acid

“…due to use of a tourniquet or other temporary occlusive devices and techniques during trauma surgeries. In these cases, IR can lead to unwanted complications through the development of an antigen-independent inflammatory process, which involves the activation and adhesion of polymorphonuclear (PMN) leukocytes in the periosteal endothelium [3] and the upregulation of several danger-associated molecular pattern-related pathways in the locally affected and contralateral limbs as well [4]. Proinflammatory cytokines (e.g.…”