The Contribution of Activated Factor XIII to Fibrinolytic Resistance in Experimental Pulmonary Embolism

Reed, Guy L.; Houng, Aiilyan K.

doi:10.1161/01.cir.99.2.299

Cited by 74 publications

(63 citation statements)

References 46 publications

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“…To examine this possibility, we used a small ␣ 2 AP peptide (␣ 2 AP 13-24 , Ϸ1600 Da), which should readily permeate the developing thrombus. We and others have verified that this peptide 5 or related peptides 16,17 can compete with crosslinking of ␣ 2 AP to fibrin when added during clotting. This peptide was biotinylated at lysine 24 to permit detection.…”

Section: Resultsmentioning

confidence: 64%

“…5 We found that the catalytic ability of FXIIIa to cross-link its physiological substrate (␣ 2 AP, 70 000 Da) into fibrin clots declined in an exponential fashion, with a half-life of 19 minutes. Similar half-lives for FXIIIa-mediated cross-linking were also found in much smaller substrates, such as ␣ 2 AP 13-24 (1600 Da), 21 minutes, and pentylamine-biotin (330 Da), 26 minutes.…”

Section: Discussionmentioning

confidence: 84%

“…FXIIIamediated fibrin ␣-chain polymerization 5,12,18 and ␥-chain multimerization 11 contribute to this fibrinolytic resistance. In addition, the cross-linking of the plasmin inhibitor ␣ 2 AP to fibrin plays a clear role in neutralizing fibrinolysis.…”

Section: Discussionmentioning

confidence: 99%

“…Samples containing cross-linked ␣ 2 AP 13-24 and pentylamine substrates were electroblotted to polyvinylidine difluoride (PVDF) membranes and detected by 125 I-streptavidin followed by phosphorimaging or by streptavidin-peroxidase and the developing agents 5-bromo-4-chloro-3-indolyl phosphate and nitro blue tetrazolium (NBT-BCIP) as we have described. 5 Phosphorimages were examined under conditions in which there was a linear relationship between substrate incorporation and pixel volume. In experiments examining the effect of specific amino acid residues on the cross-linking of the ␣ 2 AP [13][14][15][16][17][18][19][20][21][22][23][24] peptide to fibrin, cross-linking was detected by immunoblotting with an anti-peptide antibody directed against this epitope followed by 125 I-labeled protein A and phosphorimaging as described.…”

Section: Assays Of Fxiiia Catalytic Life and Substrate Specificitymentioning

confidence: 99%

“…5 A transglutaminase, FXIIIa cross-links proteins in the fibrin thrombus by forming an amide bond between specific glutamine and lysine residues, which produces a mechanically stronger clot. 6 -9 Fibrinolytic resistance is achieved when FXIIIa covalently links ␣ 2 -antiplasmin (␣ 2 AP), the plasmin inhibitor, to fibrin.…”

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confidence: 99%

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Catalytic Life of Activated Factor XIII in Thrombi

2000

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Background-Because the increased fibrinolytic resistance of older thrombi may be caused by the continuous cross-linking action of fibrin-bound activated factor XIII (FXIIIa), we examined the persistence of FXIIIa catalytic activity in clots of various ages. Methods and Results-The time-related changes in FXIIIa activity in clots was measured with (1) ␣ 2 -antiplasmin (␣ 2 AP), a physiological glutamine substrate; (2) ␣ 2 AP 13-24 , a peptide; and (3) pentylamine, a nonspecific lysine substrate. The cross-linking of ␣ 2 AP, ␣ 2 AP 13-24 , and pentylamine into fibrin by clot-bound FXIIIa declined rapidly with half-lives of 19, 21, and 26 minutes, respectively. Mutational studies showed that glutamine 14 (but not glutamine 3 or 16) and valine 17 of ␣ 2 AP 13-24 were required for efficient cross-linking to fibrin. The loss of activity was not due primarily to FXIIIa proteolysis and was partially restored by reducing agents, suggesting that oxidation contributes to the loss of the enzyme's activity in clots. In vivo, the ability of thrombus-bound FXIIIa to cross-link an infused ␣ 2 AP 13-24 peptide into existing pulmonary emboli also declined significantly over time. Conclusions-FXIIIa cross-links ␣ 2 AP and an ␣ 2 AP peptide, in a sequence-specific manner, into formed clots with a catalytic half-life of Ϸ20 minutes. This indicates that FXIIIa activity is a hallmark of new thrombi and that the antifibrinolytic cross-linking effects of FXIIIa are achieved more rapidly in thrombi than previously believed.

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Section: Resultsmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 84%