Thrombosis is a common complication of surgery that increases perioperative morbidity and mortality. For thromboprophylaxis to be practical in the perioperative setting, an approach must sustain physiologic fibrin formation to avoid perioperative bleeding and permit wound repair, while at the same time prevent pathological thrombi from forming. The investigators postulate that coupling plasminogen activators (PA's) to carrier red blood cells (RBC) will deny the enzymes ready access to mature clots or to extravascular fibrin, but will prolong their life-span within the circulation and permit them to be incorporated within newly formed clots. The preliminary results support this hypothesis and show that PAs can be coupled to RBC without loss of biocompatibility, circulate for a prolonged time and display selective fibrinolytic activity against newly formed clots in vitro and likely in vivo. The investigators have also observed that: (1) single chain urokinase (scuPA) bound to its soluble receptor (suPAR) is enzymatically active, fibrin specific, resistant to plasminogen activator inhibitor-1 (PAI-1), but its activity is regulated by the fourth kringle of plasminogen (K4); (2) a scuPA variant lacking the kringle (DK-scuPA) displays enhanced enzymatic activity, is relatively resistant to PAI-1. Retains high affinity binding to suPAR, and acquires anti-vasoconstrictor activity; (3) suPAR can be coupled to circulating RBC via complement receptor-1 (CR-1) allowing scuPA to bind to circulating RBC without ex vivo manipulation. The investigators hypothesize that coupling scuPA or DK-scuPA to RBC via suPAR will generate a latent pro-drug which has little, if any, access to mature clots, but which enjoys a prolonged life-span and ready access to nascent clots which induce its activity. Based on these findings, the investigators propose to study the behavior of RBC-coupled scuPA and DK-scuPA and efficacy and safety in animal models that recapitulate common post surgical thrombotic situations. The following specific aims will be pursued: (1) Biologic activity of uPA coupled to RBC (uPA/RBC). The stability, enzymatic and vasoregulatory activity, resistance to PAI-1, adhesivity and regulation by plasminogen of uPA/RBC will be investigated in vitro. (2) Bioavailability of UPA/RBC in vivo. The investigators will characterize the stability, blood clearance, biodistribution, and activities of uPA/RBC injected into intact animals. (3) Efficacy of uPA/RBC in animal mdels of thromboembolism. Animal models of pulmonary and cerebral embolism that have been developed in the investigators' laboratory will be employed to study uPA/RBC-mediated thromboprophylaxis in intact rodents and in genetically altered mice. The results of this study may provide new means to achieve thromboprophylaxis in surgical settings such as angioplasty and endarterectomy, as well as be a platform for the development of novel forms of antithrombotic therapy.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL066442-03
Application #
6629160
Study Section
Surgery and Bioengineering Study Section (SB)
Program Officer
Hasan, Ahmed AK
Project Start
2001-02-01
Project End
2005-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
3
Fiscal Year
2003
Total Cost
$277,375
Indirect Cost
Name
University of Pennsylvania
Department
Pharmacology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Armstead, William M; Ganguly, Kumkum; Riley, John et al. (2012) RBC-coupled tPA Prevents Whereas tPA Aggravates JNK MAPK-Mediated Impairment of ATP- and Ca-Sensitive K Channel-Mediated Cerebrovasodilation After Cerebral Photothrombosis. Transl Stroke Res 3:114-21
Kapustin, Alexander; Stepanova, Victoria; Aniol, Natalia et al. (2012) Fibulin-5 binds urokinase-type plasminogen activator and mediates urokinase-stimulated ?1-integrin-dependent cell migration. Biochem J 443:491-503
Armstead, William M; Ganguly, Kumkum; Riley, John et al. (2011) Red blood cell-coupled tissue plasminogen activator prevents impairment of cerebral vasodilatory responses through inhibition of c-Jun-N-terminal kinase and potentiation of p38 mitogen-activated protein kinase after cerebral photothrombosis in the newborn Pediatr Crit Care Med 12:e369-75
Armstead, William M; Ganguly, Kumkum; Kiessling, J W et al. (2010) Signaling, delivery and age as emerging issues in the benefit/risk ratio outcome of tPA For treatment of CNS ischemic disorders. J Neurochem 113:303-12
Armstead, William M; Ganguly, Kumkum; Kiessling, John W et al. (2009) Red blood cells-coupled tPA prevents impairment of cerebral vasodilatory responses and tissue injury in pediatric cerebral hypoxia/ischemia through inhibition of ERK MAPK activation. J Cereb Blood Flow Metab 29:1463-74
Murciano, Juan-Carlos; Higazi, Abd Al-Roof; Cines, Douglas B et al. (2009) Soluble urokinase receptor conjugated to carrier red blood cells binds latent pro-urokinase and alters its functional profile. J Control Release 139:190-6
Danielyan, Kristina; Ganguly, Kumkum; Ding, Bi-Sen et al. (2008) Cerebrovascular thromboprophylaxis in mice by erythrocyte-coupled tissue-type plasminogen activator. Circulation 118:1442-9
Ganguly, Kumkum; Murciano, Juan-Carlos; Westrick, Randal et al. (2007) The glycocalyx protects erythrocyte-bound tissue-type plasminogen activator from enzymatic inhibition. J Pharmacol Exp Ther 321:158-64
Ganguly, Kumkum; Goel, Mukul S; Krasik, Tatyana et al. (2006) Fibrin affinity of erythrocyte-coupled tissue-type plasminogen activators endures hemodynamic forces and enhances fibrinolysis in vivo. J Pharmacol Exp Ther 316:1130-6
Zaitsev, Sergei; Danielyan, Kristina; Murciano, Juan-Carlos et al. (2006) Human complement receptor type 1-directed loading of tissue plasminogen activator on circulating erythrocytes for prophylactic fibrinolysis. Blood 108:1895-902

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