This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sjöland, H. Articles by Ginsburg, D. Search for Related Content PubMed PubMed Citation Articles by Sjöland, H. Articles by Ginsburg, D. Related Collections Animal models of human disease Pathophysiology Genetically altered mice Fibrinolysis Mechanism of atherosclerosis/growth factors

(Arteriosclerosis, Thrombosis, and Vascular Biology. 2000;20:846.)
© 2000 American Heart Association, Inc.

Thrombosis

Atherosclerosis Progression in LDL Receptor–Deficient and Apolipoprotein E–Deficient Mice Is Independent of Genetic Alterations in Plasminogen Activator Inhibitor-1

Helén Sjöland; Daniel T. Eitzman; David Gordon; Randal Westrick; Elizabeth G. Nabel; David Ginsburg

From the Divisions of Cardiology (H.S., D.T.E., E.G.N.) and Molecular Medicine and Genetics (D. Ginsburg), Department of Internal Medicine, and the Department of Human Genetics (D. Ginsburg) and Howard Hughes Medical Institute (R.W., D. Ginsburg), University of Michigan Medical Center, Ann Arbor, and Cardiovascular Therapeutics (D. Gordon), Parke-Davis Pharmaceutical Research, Ann Arbor, Mich.

Correspondence to David Ginsburg, MD, Department of Human Genetics, Howard Hughes Medical Institute, University of Michigan Medical Center, 4520 MSRB I, 1150 W Medical Center Dr, Ann Arbor, MI 48109-0644. E-mail ginsburg{at}umich.edu

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Abstract—Impaired fibrinolysis has been linked to atherosclerosis in a number of experimental and clinical studies. Plasminogen activator inhibitor type 1 (PAI-1) is the primary inhibitor of plasminogen activation and has been proposed to promote atherosclerosis by facilitating fibrin deposition within developing lesions. We examined the contribution of PAI-1 to disease progression in 2 established mouse models of atherosclerosis. Mice lacking apolipoprotein E (apoE-/-) and mice lacking the low density lipoprotein receptor (LDLR-/-) were crossbred with transgenic mice overexpressing PAI-1 (resulting in PAI-1 Tg⁺/apoE-/- and PAI-1 Tg⁺/LDLR-/-, respectively) or were crossbred with mice completely deficient in PAI-1 gene expression (resulting in PAI-1-/-/apoE-/- and PAI-1-/-/LDLR-/-, respectively). All animals were placed on a western diet (21% fat and 0.15% cholesterol) at 4 weeks of age and analyzed for the extent of atherosclerosis after an additional 6, 15, or 30 weeks. Intimal and medial areas were determined by computer-assisted morphometric analysis of standardized microscopic sections from the base of the aorta. Atherosclerotic lesions were also characterized by histochemical analyses with the use of markers for smooth muscle cells, macrophages, and fibrin deposition. Typical atherosclerotic lesions were observed in all experimental animals, with greater severity at the later time points and generally more extensive lesions in apoE-/- than in comparable LDLR-/- mice. No significant differences in lesion size or histological appearance were observed among PAI-1-/-, PAI-1 Tg⁺, or PAI-1 wild-type mice at any of the time points on either the apoE-/- or LDLR-/- genetic background. We conclude that genetic modification of PAI-1 expression does not significantly alter the progression of atherosclerosis in either of these well-established mouse models. These results suggest that fibrinolytic balance (as well as the potential contribution of PAI-1 to the regulation of cell migration) plays only a limited role in the pathogenesis of the simple atherosclerotic lesions observed in the mouse.

Key Words: atherosclerosis • plasminogen activator inhibitor-1 • apolipoprotein E • low density lipoprotein receptors • transgenic mice

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
The development of human atherosclerosis is slowly progressive over time. Typically, the process starts in youth with the inclusion of lipid-rich cells in the arterial intima, gradually proceeds to macrophage and smooth muscle cell involvement, and, in its later stages, forms the complex, sometimes occlusive, fibrous plaque, often with a thrombotic component.¹ Plaque disruption may lead to acute thrombosis and vascular occlusion, resulting in myocardial infarction.² Atherosclerosis is a multifactorial disease with variation in plasma levels for several coagulation factors,¹ most notably, fibrinogen³ and factor VII,⁴ known to be among the most significant risk factors for vascular disease. In conjunction with the demonstration of extensive fibrin deposition in most complex lesions,^{5 6} these observations suggest that thrombosis is a critical component in the pathogenesis of human atherosclerosis.

Plasminogen activator inhibitor-1 (PAI-1) is the primary inhibitor of the physiological plasminogen activators, tissue plasminogen activator and urokinase plasminogen activator. Decreased fibrinolytic activity has been proposed to accelerate the process of arterial atherogenesis by facilitating thrombosis and fibrin deposition within developing atherosclerotic lesions. Elevated plasma PAI-1 has been identified as a risk factor for myocardial infarction and reinfarction^{7 8} and has been linked to the presence and development of coronary artery disease,^{9 10 11} although the latter association has not been confirmed in all studies.^{12 13} In addition to its well-defined role in fibrinolysis, PAI-1 may also contribute to the regulation of smooth muscle cell migration,¹⁴ potentially through its interactions with vitronectin, urokinase plasminogen activator, and the urokinase plasminogen activator receptor.^{15 16 17}

The generation of atherosclerosis-prone mice, through genetic manipulations targeted primarily to genes affecting lipoprotein metabolism, has provided a powerful experimental system for the study of the molecular and cellular pathogenesis of atherosclerosis.¹⁸ However, there are a number of potential problems with the application of these systems as a model for the human disease, including obvious differences in cardiovascular physiology. In addition, all the murine atherosclerotic models developed to date lack the complex thrombotic lesions typically seen in humans, and the progression to thrombo-occlusion, characteristic of human stroke and myocardial infarction, has not yet been observed in the mouse.^{19 20}

Studies in the mouse to determine the role of fibrin deposition and hemostatic balance in the progression of atherosclerosis have yielded conflicting results. Although fibrin deposition can be demonstrated in murine atherosclerotic lesions, mice engineered to be completely deficient in fibrinogen are not protected from the development of atherosclerosis in the setting of apoE deficiency.²¹ In contrast, a block to fibrin clearance through targeted deletion of the plasminogen gene appears to accelerate atherogenesis in the apoE-null (apoE-/-) mouse.²²

To further explore the hypothesis that variations in endogenous fibrinolytic activity might significantly alter the process of atherosclerosis, we examined the effect of genetic modification of PAI-1 expression in 2 well-established models for atherosclerosis, apoE-/- mice²³ and LDL receptor–null (LDLR-/-)²⁴ mice. These atherosclerosis-prone mice were crossbred with PAI-1–deficient (PAI-1-/-) and PAI-1–overexpressing transgenic (PAI-1 Tg⁺) mice, and the genetic compound offspring were evaluated for atherosclerosis progression on a high-fat (western) diet. No significant differences were observed in susceptibility to atherosclerosis as a function of PAI-1 genetic status. These results suggest that fibrinolytic balance (as well as the potential contribution of PAI-1 to the regulation of cell migration) plays only a limited role in the pathogenesis of the simple atherosclerotic lesions observed in these mouse models.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Animals
All animal experiments were performed in accordance with institutional guidelines at the University of Michigan. ApoE-/-²⁵ and LDLR-/- mice²⁴ were obtained from Jackson Laboratories (Bar Harbor, Me). PAI-1-/- mice also previously generated by homologous recombination were a generous gift from D. Collen and P. Carmeliet (University of Leuven, Leuven, Belgium).²⁶ Transgenic mice overexpressing a murine PAI-1 minigene under the direction of the CMV promoter have been previously described.^{27 28} All PAI-1 Tg⁺, PAI-1-/-, apoE-/-, and LDLR-/- mice were serially backcrossed to C57BL/6J for at least 6 generations. Genotyping for all alleles was performed by polymerase chain reaction analysis of tail DNA specimens obtained at 3 weeks of age. The polymerase chain reaction conditions for the PAI-1-/- and PAI-1 Tg⁺ alleles have been previously described.²⁸ For apoE and LDLR, mice were genotyped with the use of 3 primer sets that specifically amplified the wild-type or knockout apoE or LDLR allele (for apoE, 5'-GCC TAG CCG AGG GAG AGC CG-3', 5'-TGT GAC TTG GGA GCT CTG CAG C-3', and 5'-GCC GCC CCG ACT GCA TCT-3'; for LDLR, 5'-CCC ACT GCC AGG CCA CCA CTT-3', 5'-CGC AGT GCT CCT CAT CTG ACT TGT-3', and 5'-AAT AGC CTC TCC ACC CAA GCG G-3'). Crosses were performed between PAI-1-/- or PAI-1 Tg⁺ mice and either apoE-/- or LDLR-/- mice to generate the desired compound genotypes. Mice were weaned at 3 weeks of age and maintained on normal chow for 1 week (PicoLab Rodent Chow); thereafter, they were started on a high-cholesterol chow diet (Teklad Adjusted Calories Western-Type Diet, consisting of 21% [wt/wt] fat [polyunsaturated/saturated ratio 0.07], 0.15% [wt/wt] cholesterol, 19.5% [wt/wt] casein, and no sodium cholate). High-cholesterol diets were maintained for 6, 15, or 30 weeks, at which point animals were euthanized for study. The genotypes, duration of western diet, and number of animals for each study group are shown in the Table.

View this table: [in this window] [in a new window]   Table 1. Characteristics of the Mice

Morphological Analysis
Mice were perfusion-fixed with 4% paraformaldehyde under intraperitoneal pentobarbital anesthesia (100 mg/kg). The heart and proximal aorta were dissected and embedded in paraffin, and standard sections were obtained from the proximal aorta at the level of the aortic valve leaflets. This area is a site of predilection for atherosclerotic lesion development in apoE-/- and LDLR-/- mice^{19 23 24} and provides anatomic landmarks to facilitate standardized measurements.²⁹ Serial sections at 5-µm intervals were inspected by progressing through the ascending aorta until all 3 aortic valve leaflets were identified in a single section. Two sections were then obtained at this level, spaced 50 µm apart, stained with hematoxylin and eosin, and subjected to quantitative morphometric analysis. Measurements of intimal and medial area were performed by use of a microscope-based video image analysis system (Image One Systems).³⁰ Intimal and medial boundaries were determined by digital planimetry at the 2 levels in each animal, and the mean value was calculated. The measurements were performed by an operator blinded to mouse genotype and age. Additional analysis of longitudinal sections was performed for 30-week apoE-/- and PAI-1-/-/apoE-/- mice. A 1.5-mm segment of the lesser curvature of the aortic arch was analyzed by methods previously described.³¹

Immunohistochemistry
By use of methods previously described,³² immunohistochemical studies were performed with antibody reagents against smooth muscle -actin, macrophages, fibrinogen, and PAI-1. The following primary antibodies were used: a monoclonal mouse anti–smooth muscle -actin antibody, 1:100 dilution (Boehringer-Mannheim Biochemical Division); a monoclonal rat anti-mouse BM 8 antibody, 1:20 dilution (BMA Biomedicals); a polyclonal goat anti-mouse fibrinogen antibody, 1:5000 dilution (Accurate); and a polyclonal rabbit anti-mouse PAI-1 antibody, dilution 1:500 (gift of D. Loskutoff, La Jolla, Calif).

Plasma Cholesterol Levels
Blood was drawn from the retro-orbital venous plexus at the time of euthanasia, and plasma cholesterol levels were measured by using a commercial kit (Sigma Chemical Co).

Statistics
Statistical analyses were performed with use of the SPSS package (SPSS 7.5, SPSS Inc). Values are expressed as mean±SEM. Mice with genetic modifications of PAI-1 crossbred with apoE-/- mice were compared with respect to weight, sex, cholesterol levels, intimal areas, medial areas, and intima-to-media ratios by ANOVA for repeated measurements. The fixed factors tested were time point and sex, with weight as a covariate. Comparison of intimal lesion size between the LDLR -/- and apoE -/- models was also performed by ANCOVA. Assistance with statistical analysis was provided by the Center for Statistical Consultation and Research, University of Michigan, Ann Arbor.

	Results

Top Abstract Introduction Methods Results Discussion References

 
A total of 117 mice with varying combinations of genotypes were evaluated for the development of atherosclerosis after 6 to 30 weeks on a high-fat (western) diet. The number of animals in each subgroup is shown in the Table. There were no significant differences between the study groups at any time point with respect to sex distribution or weight. As expected, apoE-/-²³ and LDLR-/-²⁴ mice developed severe hypercholesterolemia, although elevations of cholesterol in the latter group were more pronounced than previously described. However, within the apoE-/- or LDLR-/- groups, there were no significant differences in cholesterol levels at euthanasia.

Atherosclerosis Lesion Development
Mean intimal area, medial area, and intima-to-media ratio for all time points are shown in Figure 1. The size of atherosclerotic lesions increased over time, and the pace of progression was similar for all PAI-1 subgroups within each of the study models (the apoE-/- versus the LDLR-/-), with no significant differences among subgroups in mean intimal area, medial area, and intima-to-media ratios, as measured in the proximal aorta (Figure 1). The oldest group in the apoE-/- model was also analyzed for lesions in the lesser curvature of the aortic arch, where intimal and medial areas, respectively, were as follows: for the PAI-1-/-/apoE-/- mice, 0.59±0.14 and 0.10±0.02 mm²; for the apoE-/- mice, 0.52±0.07 and 0.09±0.01 mm² (P=NS).

View larger version (39K): [in this window] [in a new window]   Figure 1. Intimal and medial areas measured at the base of the aortic root. Values are shown as mean±SEM for each subgroup of animals at each time point. Data for apoE-/- mice (A) and LDLR-/- mice (B) are shown. Comparisons among PAI-1 genotypes revealed no significant differences at any time point. I/M ratio indicates the intima-to-media ratio; open bars, PAI-1-/- mice; shaded bars, wild-type control mice; and solid bars, PAI-1 Tg+ mice.

For all of the apoE-/- subgroups, intimal lesion area increased from 0.15 mm² at 6 weeks to 0.6 mm² at 15 weeks and 1 mm² after 30 weeks, with medial areas remaining relatively constant (Figure 1A). Figure 1B shows the corresponding data for the LDLR-/- mice. The size of the lesions observed in LDLR-/- mice was somewhat smaller, varying from 0.3 mm² at 15 weeks to 0.8 mm² at 30 weeks (P<0.001 by ANCOVA). Although LDLR-/- mice require a high-fat diet to display atherosclerotic lesions, apoE-/- mice on normal chow also develop lesions and are generally thought to exhibit more severe disease conditions than do LDLR-/- mice on a western diet.¹⁹ Our results provide a direct comparison between these models, confirming the occurrence of more severe disease in apoE-/- mice, although the difference may be less marked than is generally assumed. Control wild-type C57BL/6 mice (n=5) as well as control mice carrying only the PAI-1 transgene (n=7) failed to develop measurable atherosclerotic lesions in the proximal aorta even after 30 weeks of the western diet (Figure 2a). These results are expected, because C57BL/6 mice generally develop measurable atherosclerosis only on an extreme high cholesterol diet.²⁹ Our data have also demonstrated that overexpression of PAI-1 alone is not sufficient to induce significant disease on this diet. In contrast, a typical early atherosclerotic lesion rich in foam cells is seen in an apoE-/- mouse after only 6 weeks of the western diet (Figure 2b). Progressive lesions with a more complex cellular composition are seen at 15 weeks in apoE-/- (Figure 2c) and LDLR-/- (Figure 2d) mice, although they are less severe in LDLR-/- mice.

View larger version (116K): [in this window] [in a new window]   Figure 2. Histological sections of atherosclerotic lesions. a and b, Representative aortic sections from PAI-1 Tg+ mouse after 30 weeks on a western diet (a) compared with apoE-/- mouse (b) after only 6 weeks of western diet. c and d, ApoE-/- mouse (c) and LDLR-/- mouse (d) after 15 weeks of western diet. Sections are stained with hematoxylin and eosin and photographed at x100 magnification. Arrows mark the internal elastic lamina.

Cellular Composition of Atherosclerotic Lesions
Histochemical analysis of atherosclerotic lesions from PAI-1 Tg⁺/apoE-/-, PAI-1-/-/apoE-/-, and apoE-/- mice after 15 weeks of western diet are shown in Figure 3. A similar histological pattern is seen, regardless of PAI-1 genotype. A greater foam cell content was seen at early time points, with more prominent cholesterol clefts and necrotic areas evident with increasing age (data not shown). Consistent with previous studies of human atherosclerotic arteries,^{33 34} scattered PAI-1 antigen was detected in atherosclerotic lesions of PAI-1 Tg⁺ and wild-type PAI-1 mice, although, as expected, immunoreactive PAI-1 was absent from PAI-1-/- arteries. Consistent with previous studies of mouse atherosclerotic lesions,²¹ fibrin was observed in a patchy distribution in apoE-/- mice. Enhanced endogenous tissue plasminogen activator activity in PAI-1-/- mice would be expected to result in decreased fibrin deposition in the lesions developing in these animals. However, this was not observed histologically. Although the sections in Figure 3 show increased staining in the PAI-1-/-/apoE-/- mice compared with the apoE-/- control mice and PAI-1 Tg+/apoE-/- mice, the level of fibrin deposition was certainly not decreased in the PAI-1-/- mice, and no consistent differences were observed across multiple sections. Staining for macrophages and smooth muscle cells was similar in the lesions of all 3 groups, with more marked staining for macrophages at the youngest ages and increasing smooth muscle cells at later time points (data not shown).

View larger version (119K): [in this window] [in a new window]   Figure 3. Immunohistochemical staining of atherosclerotic lesions. Sections were stained with hematoxylin and eosin (H&E), PAI-1, and fibrin in representative atherosclerotic lesions from transgene (PAI-1 Tg+/apoE-/-), knockout (PAI-1-/-/apoE-/-), and apoE-/- control mice. Arrows mark the internal elastic lamina. PAI-1 staining gives a red reaction product and was scarcely present in the lesions of PAI-1 Tg+ and wild-type PAI-1 mice but was absent in PAI-1-/- mice. The fibrin content (pink stain) of the lesions was similar in the 3 groups.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
Considerable circumstantial evidence currently implicates alterations in PAI-1 gene expression in the pathogenesis of human atherosclerosis.^{7 8 9 10 11} Because PAI-1 is the primary regulator of fibrinolytic activity in vivo, alterations in PAI-1 might be expected to significantly modify the risk of the development of atherosclerosis, with higher levels of PAI-1 resulting in decreased endogenous fibrinolysis favoring the progression of atherosclerosis and low levels providing some degree of protection. Consistent with this hypothesis, a common polymorphism within the PAI-1 promoter that influences PAI-1 gene transcription in vitro has been shown to be associated with the risk of atherosclerosis in several studies,^{35 36} although this association is not confirmed in others.³⁷

The biologically relevant source of PAI-1 for the pathogenesis of atherosclerosis is unclear and could include the free plasma pool, the large though predominantly latent pool of PAI-1 within the platelet -granule, and PAI-1 localized to the vessel wall (from plasma, smooth muscle cells, or endothelial cells).³⁸ In addition to regulating fibrinolysis within the vessel wall, PAI-1 may also play an important role in controlling smooth muscle cell migration and vascular wall remodeling.^{14 15} Consistent with a proposed atherogenic role of vascular wall PAI-1, high levels of PAI-1 expression have been demonstrated in human atherosclerotic lesions.^{33 39}

Fibrin is a central component of the atherosclerotic plaque,^{5 6} and the plasma fibrinogen level is a strong independent risk factor for heart disease. Consistent with a pivotal role for endogenous fibrinolysis as a protection against fibrin deposition, plasminogen deficiency leads to more rapid progression of atherosclerosis in apoE-/- mice.²² However, this latter observation appears to directly contradict the results reported in the present study, because neither a genetic increase nor a decrease in PAI-1 altered atherosclerosis progression in the apoE-/- or LDLR-/- model. Overexpression of PAI-1 would be expected to inhibit plasminogen activation and should thus resemble mild plasminogen deficiency. In contrast, PAI-1 deficiency should result in an elevated basal level of plasmin activity, which should be protective.

There are several potential explanations for the apparent discrepancy between these 2 sets of experiments. Potential changes in the severity of atherosclerosis that might result from genetic manipulations at the PAI-1 locus may be subtle compared with the effect of a complete block of plasmin activity. Alternatively, the contrasting effects on the progression of atherosclerosis may be due to secondary differences in phenotype between plasminogen-null mice and the animals used in the present study. It is also possible that an alternative protease inhibitor in mice (in contrast to humans) overlaps with PAI-1 function. However, no such alternative regulator has yet been identified, and accelerated fibrinolysis has been demonstrated in PAI-1-/- mice,⁴⁰ producing a fibrinolytic defect similar to that observed in humans.⁴¹

It is important to note that plasminogen-deficient mice exhibit markedly increased mortality and severe runting (which most likely result from widespread thrombosis and chronic organ damage) as well as related infectious complications.⁴² In contrast, PAI-1-/- and PAI-1 Tg⁺ mice exhibit normal weights and survival. The accelerated atherosclerosis observed in plasminogen-null animals could be secondary to the effects of chronic illness, including elevated levels for a number of inflammatory cytokines, rather than a direct result of decreased basal fibrinolysis. Consistent with this view, fibrinogen-deficient mice show no difference in the rate of the progression of atherosclerosis on an apoE-null background, demonstrating that fibrin deposition is not required for this process.²¹ Taken together, these results argue against a major role for plasminogen activation or the PAI-1–vitronectin interaction in the development of atherosclerosis, at least in these mouse models.

The lack of a significant effect of PAI-1 on the progression of atherosclerosis in the mouse suggests that the role of PAI-1 in human atherosclerosis may be less important than previously thought. The mouse offers a powerful model for dissecting complex gene interactions, and the LDLR-/- and apoE-/- mice are currently the best available models for the human disease. However, there are a number of serious limitations to all of the currently available mouse models for human atherosclerosis that must be kept in mind when interpreting these data.^{18 19} The apoE and LDLR mouse models rely on lipid deposition in the vessel wall as the sole pathophysiological mechanism, in contrast to the known complex multifactorial pathogenesis of human atherosclerosis. These induced lipid abnormalities are much more extreme than those generally occurring in humans, and the time courses are rapidly accelerated, with lesions appearing in mice within 6 to 15 weeks that could take >30 years to develop in humans. Such exaggerated kinetics might mask a subtle contribution from altered fibrinolytic balance. In addition, the markedly different hemodynamic environments of mice and humans, along with other factors operating in humans, such as infections, inflammation, and thrombosis, may contribute to the development of the complex human lesion. Of note, the advanced complex lesion seen in humans generally exhibits significant fibrin deposition and a critical thrombotic component that has not yet been observed in mice. In addition, fibrinolytic balance may be a key determinant of the thrombotic response to plaque rupture that results in myocardial infarction.

Refinement of the LDLR model by the addition of a human apoB transgene⁴³ or deletion of the apoB mRNA editing enzyme⁴⁴ has recently been shown to result in the progression of atherosclerosis, even when the mice are fed a normal chow diet. Similarly, although fibrinogen deficiency does not alter atherogenesis in apoE-/- mice,²¹ reduction of fatty streak development was recently observed in a model based on a human apo(a) transgene.⁴⁵ With continued progress in genetic engineering, improved mouse models that more faithfully reproduce the complex pathogenesis of human atherosclerosis may become available. Future models will likely introduce a significant thrombotic component, and in this setting, it may be possible to assess more accurately the contribution of variations in endogenous fibrinolysis. Such models may also facilitate the preclinical evaluation of PAI-1 as a therapeutic target for reduction of the risk of atherosclerosis and myocardial infarction.

In summary, our results demonstrate that PAI-1 functional activity is not an essential component of the progression of atherosclerosis in the LDLR knockout and apoE knockout mouse models. These results suggest that fibrinolytic balance, as well as the potential contribution of PAI-1 to the regulation of cell migration, is not essential to the pathogenesis of the simple atherosclerotic lesion observed in mice. However, a significant role in the development of the more complex human lesion, or in predisposition to the acute thrombotic events associated with myocardial infarction, cannot be excluded.

	Acknowledgments

 
This study was supported by grants from the National Institutes of Health PO1-HL-57346 (E.G.N., D. Ginsburg), RO1-HL-49184 (D. Ginsburg), and KO8-HL-03695-01 (D.T.E.). H.S. was supported by the Swedish Medical Research Council and the Swedish Society for Medical Research. E.G.N. is an Established Investigator of the American Heart Association. D. Ginsburg is a Howard Hughes Medical Institute Investigator. We are grateful to H. San, L. Xu, and J. Tyson for expert technical assistance.

Received June 14, 1999; accepted October 1, 1999.

	References

Top Abstract Introduction Methods Results Discussion References

 
1. Ross R. The pathogenesis of atherosclerosis: a perspective for the 1990s. Nature. 1993;362:801–809.[Medline] [Order article via Infotrieve]

2. Davies MJ, Thomas A. Thrombosis and acute coronary-artery lesions in sudden cardiac ischemic death. N Engl J Med. 1984;310:1137–1140.[Abstract]

3. Wilhelmsen L, Svärdsudd K, Korsan-Bengtson K, Larsson B, Welin L, Tibblin G. Fibrinogen as a risk factor for stroke and myocardial infarction. N Engl J Med. 1984;311:501–505.[Abstract]

4. Meade TW, Mellows S, Brozovic M, Miller GJ, Chakrabarti RR, North WR, Haines AP, Stirling Y, Imeson JD, Thompson SG. Haemostatic function and ischaemic heart disease: principal results of the Northwick Park Heart Study. Lancet. 1986;2:533–537.[Medline] [Order article via Infotrieve]

5. Schwartz CJ, Valente AJ, Kelley JL, Sprague EA, Edwards EH. Thrombosis and the development of atherosclerosis: Rokitansky revisited. Semin Thromb Hemost. 1988;14:189–195.[Medline] [Order article via Infotrieve]

6. Bini A, Fenoglio JJJ, Mesa-Tejada R, Kudryk B, Kaplan KL. Identification and distribution of fibrinogen, fibrin, and fibrin(ogen) degradation products in atherosclerosis: use of monoclonal antibodies. Arteriosclerosis. 1989;9:109–121.[Abstract/Free Full Text]

7. Hamsten A, Wiman B, de Faire U, Blombäck M. Increased plasma levels of a rapid inhibitor of tissue plasminogen activator in young survivors of myocardial infarction. N Engl J Med. 1985;313:1557–1563.[Abstract]

8. Hamsten A, de Faire U, Walldius G, Dahlen G, Szamosi A, Landou C, Blombäck M, Wiman B. Plasminogen activator inhibitor in plasma: risk factor for recurrent myocardial infarction. Lancet. 1987;2:3–9.[Medline] [Order article via Infotrieve]

9. Francis RB Jr, Kawanishi D, Baruch T, Mahrer P, Rahimtoola S, Feinstein DI. Impaired fibrinolysis in coronary artery disease. Am Heart J. 1988;115:776–780.[Medline] [Order article via Infotrieve]

10. Olofsson BO, Dahlen G, Nilsson TK. Evidence for increased levels of plasminogen activator inhibitor and tissue plasminogen activator in plasma of patients with angiographically verified coronary artery disease. Eur Heart J. 1989;10:77–82.[Abstract/Free Full Text]

11. Cortellaro M, Cofrancesco E, Boschetti C, Mussoni L, Donati MB, Cardillo M, Catalano M, Gabrielli L, Lombardi B, Specchia G. Increased fibrin turnover and high PAI-1 activity as predictors of ischemic events in atherosclerotic patients: a case-control study: the PLAT Group. Arterioscler Thromb. 1993;13:1412–1417.[Abstract/Free Full Text]

12. Thompson SG, Kienast J, Pyke SDM, Haverkate F, van de Loo JCW. Hemostatic factors and the risk of myocardial infarction or sudden death in patients with angina pectoris. N Engl J Med. 1995;332:635–641.[Abstract/Free Full Text]

13. Ridker PM, Hennekens CH, Schmitz C, Stampfer MJ, Lindpaintner K. PIA1/A2 polymorphism of platelet glycoprotein IIIa and risks of myocardial infarction, stroke, and venous thrombosis. Lancet. 1997;349:385–388.[Medline] [Order article via Infotrieve]

14. Carmeliet P, Moons L, Ploplis V, Plow EF, Collen D. Impaired arterial neointima formation in mice with disruption of the plasminogen gene. J Clin Invest. 1997;99:200–208.[Medline] [Order article via Infotrieve]

15. Stefansson S, Lawrence DA. The serpin PAI-1 inhibits cell migration by blocking integrin _vß₃ binding to vitronectin. Nature. 1996;383:441–391.[Medline] [Order article via Infotrieve]

16. Chavakis T, Kanse SM, Yutzy B, Lijnen HR, Preissner KT. Vitronectin concentrates proteolytic activity on the cell surface and extracellular matrix by trapping soluble urokinase receptor-urokinase complexes. Blood. 1998;91:2305–2312.[Abstract/Free Full Text]

17. Deng G, Curriden SA, Wang SJ, Rosenberg S, Loskutoff DJ. Is plasminogen activator inhibitor-1 the molecular switch that governs urokinase receptor-mediated cell adhesion and release? J Cell Biol. 1996;134:1563–1571.[Abstract/Free Full Text]

18. Smithies O, Maeda N. Gene targeting approaches to complex genetic diseases: atherosclerosis and essential hypertension. Proc Natl Acad Sci U S A. 1995;92:5266–5272.[Abstract/Free Full Text]

19. Breslow JL. Mouse models of atherosclerosis. Science. 1996;272:685–688.[Abstract]

20. Rader DJ, Fitzgerald GA. State of the art: atherosclerosis in a limited edition. Nat Med. 1998;4:899–900.[Medline] [Order article via Infotrieve]

21. Xiao Q, Danton MJ, Witte DP, Kowala MC, Valentine MT, Degen JL. Fibrinogen deficiency is compatible with the development of atherosclerosis in mice. J Clin Invest. 1998;101:1184–1194.[Medline] [Order article via Infotrieve]

22. Xiao Q, Danton MJS, Witte DP, Kowala MC, Valentine MT, Bugge TH, Degen JL. Plasminogen deficiency accelerates vessel wall disease in mice predisposed to atherosclerosis. Proc Natl Acad Sci U S A. 1997;94:10335–10340.[Abstract/Free Full Text]

23. Nakashima Y, Plump AS, Raines EW, Breslow JL, Ross R. ApoE-deficient mice develop lesions of all phases of atherosclerosis throughout the arterial tree. Arterioscler Thromb. 1994;14:133–140.[Abstract/Free Full Text]

24. Ishibashi S, Goldstein JL, Brown MS, Herz J, Burns DK. Massive xanthomatosis and atherosclerosis in cholesterol-fed low density lipoprotein receptor-negative mice. J Clin Invest. 1994;93:1885–1893.

25. Zhang SH, Reddick RL, Piedrahita JA, Maeda N. Spontaneous hypercholesterolemia and arterial lesions in mice lacking apolipoprotein E. Science. 1992;258:468–471.[Abstract/Free Full Text]

26. Carmeliet P, Kieckens L, Schoonjans L, Ream B, Van Nuffelen A, Prendergast GC, Cole MD, Bronson R, Collen D, Mulligan RC. Plasminogen activator inhibitor-1 gene-deficient mice, I: generation by homologous recombination and characterization. J Clin Invest. 1993;92:2746–2755.

27. Eitzman DT, McCoy RD, Zheng X, Fay WP, Shen T, Ginsburg D, Simon RH. Bleomycin-induced pulmonary fibrosis in transgenic mice that either lack or overexpress the murine plasminogen activator inhibitor-1 gene. J Clin Invest. 1996;97:232–237.[Medline] [Order article via Infotrieve]

28. Eitzman DT, Krauss JC, Shen T, Cui J, Ginsburg D. Lack of plasminogen activator inhibitor-1 effect in a transgenic mouse model of metastatic melanoma. Blood. 1996;87:4718–4722.[Abstract/Free Full Text]

29. Paigen B, Morrow A, Holmes PA, Mitchell D, Williams RA. Quantitative assessment of atherosclerotic lesions in mice. Atherosclerosis. 1987;68:231–240.[Medline] [Order article via Infotrieve]

30. Pompili VJ, Gordon D, San H, Yang Z, Muller DW, Nabel GJ, Nabel EG. Expression and function of a recombinant PDGF B gene in porcine arteries. Arterioscler Thromb Vasc Biol. 1995;15:2254–2264.[Abstract/Free Full Text]

31. Mach F, Schönbeck U, Sukhova GK, Atkinson E, Libby P. Reduction of atherosclerosis in mice by inhibition of CD40 signalling. Nature. 1998;394:200–203.[Medline] [Order article via Infotrieve]

32. Simari RD, San H, Rekhter M, Ohno T, Gordon D, Nabel GJ, Nabel EG. Regulation of cellular proliferation and intimal formation following balloon injury in atherosclerotic rabbit arteries. J Clin Invest. 1996;98:225–235.[Medline] [Order article via Infotrieve]

33. Lupu F, Bergonzelli GE, Heim DA, Cousin E, Genton CY, Bachmann F, Kruithof EKO. Localization and production of plasminogen activator inhibitor-1 in human healthy and atherosclerotic arteries. Arterioscler Thromb. 1993;13:1090–1100.[Abstract/Free Full Text]

34. Taatjes DJ, Wadsworth M, Absher PM, Sobel BE, Schneider DJ. Immunoelectron microscopic localization of plasminogen activator inhibitor type 1 (PAI-1) in smooth muscle cells from morphologically normal and atherosclerotic human arteries. Ultrastruct Pathol. 1997;21:527–536.[Medline] [Order article via Infotrieve]

35. Dawson SJ, Wiman B, Hamsten A, Green F, Humphries S, Henney AM. The two allele sequences of a common polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene respond differently to interleukin-1 in HepG2 cells. J Biol Chem. 1993;268:10739–10745.[Abstract/Free Full Text]

36. Eriksson P, Kallin B, Van’t Hooft FM, Båvenholm P, Hamsten A. Allele-specific increase in basal transcription of the plasminogen- activator inhibitor 1 gene is associated with myocardial infarction. Proc Natl Acad Sci U S A. 1995;92:1851–1855.[Abstract/Free Full Text]

37. Ridker PM, Hennekens CH, Lindpaintner K, Stampfer MJ, Miletich JP. Arterial and venous thrombosis is not associated with the 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor gene in a large cohort of US men. Circulation. 1997;95:59–62.[Abstract/Free Full Text]

38. Eitzman DT, Ginsburg D. Of mice and men: the function of plasminogen activator inhibitors (PAIs) in vivo. Adv Exp Med Biol. 1997;131–141.

39. Schneiderman J, Bordin GM, Engelberg I, Adar R, Seiffert D, Thinnes T, Bernstein EF, Dilley RB, Loskutoff DJ. Expression of fibrinolytic genes in atherosclerotic abdominal aortic aneurysm wall: a possible mechanism for aneurysm expansion. J Clin Invest. 1995;96:639–645.

40. Carmeliet P, Stassen JM, Schoonjans L, Ream B, van den Oord JJ, De Mol M, Mulligan RC, Collen D. Plasminogen activator inhibitor-1 gene-deficient mice, II: effects on hemostasis, thrombosis, and thrombolysis. J Clin Invest. 1993;92:2756–2760.

41. Fay WP, Shapiro AD, Shih JL, Schleef RR, Ginsburg D. Complete deficiency of plasminogen-activator inhibitor type 1 due to a frame-shift mutation. N Engl J Med. 1992;327:1729–1733.[Medline] [Order article via Infotrieve]

42. Bugge TH, Flick MJ, Daugherty CC, Degen JL. Plasminogen deficiency causes severe thrombosis but is compatible with development and reproduction. Genes Dev. 1995;9:794–807.[Abstract/Free Full Text]

43. Sanan DA, Newland DL, Tao R, Marcovina S, Wang J, Mooser V, Hammer RE, Hobbs HH. Low density lipoprotein receptor-negative mice expressing human apolipoprotein B-100 develop complex atherosclerotic lesions on a chow diet: no accentuation by apolipoprotein. Proc Natl Acad Sci U S A. 1998;95:4544–4549.[Abstract/Free Full Text]

44. Powell-Braxton L, Véniant M, Latvala RD, Hirano K-I, Won WB, Ross J, Dybdal N, Zlot CH, Young SG, Davidson NO. A mouse model of human familial hypercholesterolemia: markedly elevated low density lipoprotein cholesterol levels and severe atherosclerosis on a low-fat chow diet. Nat Med. 1998;4:934–938.[Medline] [Order article via Infotrieve]

45. Lou XJ, Boonmark NW, Horrigan FT, Degen JL, Lawn RM. Fibrinogen deficiency reduces vascular accumulation of apolipoprotein(a) and development of atherosclerosis in apolipoprotein(a) transgenic mice. Proc Natl Acad Sci U S A. 1998;95:12591–12595.[Abstract/Free Full Text]

This article has been cited by other articles:

				M. Drinane, J. Mollmark, L. Zagorchev, K. Moodie, B. Sun, A. Hall, S. Shipman, P. Morganelli, M. Simons, and M. J. Mulligan-Kehoe The Antiangiogenic Activity of rPAI-123 Inhibits Vasa Vasorum and Growth of Atherosclerotic Plaque Circ. Res., February 13, 2009; 104(3): 337 - 345. [Abstract] [Full Text] [PDF]

				S. Zadelaar, R. Kleemann, L. Verschuren, J. de Vries-Van der Weij, J. van der Hoorn, H. M. Princen, and T. Kooistra Mouse Models for Atherosclerosis and Pharmaceutical Modifiers Arterioscler Thromb Vasc Biol, August 1, 2007; 27(8): 1706 - 1721. [Abstract] [Full Text] [PDF]

				W. P. Fay, N. Garg, and M. Sunkar Vascular Functions of the Plasminogen Activation System Arterioscler Thromb Vasc Biol, June 1, 2007; 27(6): 1231 - 1237. [Abstract] [Full Text] [PDF]

				P. F. Bodary, Y. Shen, M. Ohman, K. L. Bahrou, F. B. Vargas, S. S. Cudney, K. J. Wickenheiser, M. G. Myers Jr, and D. T. Eitzman Leptin Regulates Neointima Formation After Arterial Injury Through Mechanisms Independent of Blood Pressure and the Leptin Receptor/STAT3 Signaling Pathways Involved in Energy Balance Arterioscler Thromb Vasc Biol, January 1, 2007; 27(1): 70 - 76. [Abstract] [Full Text] [PDF]

				E. M. Kairuz, M. N. Barber, C. R. Anderson, M. Kanagasundaram, G. R. Drummond, and R. L. Woods C-type natriuretic peptide (CNP) suppresses plasminogen activator inhibitor-1 (PAI-1) in vivo Cardiovasc Res, June 1, 2005; 66(3): 574 - 582. [Abstract] [Full Text] [PDF]

				D. T. Eitzman, R. J. Westrick, Y. Shen, P. F. Bodary, S. Gu, S. L. Manning, S. L. Dobies, and D. Ginsburg Homozygosity for Factor V Leiden Leads to Enhanced Thrombosis and Atherosclerosis in Mice Circulation, April 12, 2005; 111(14): 1822 - 1825. [Abstract] [Full Text] [PDF]

				D. J. Schneider, M. Hayes, M. Wadsworth, H. Taatjes, M. Rincon, D. J. Taatjes, and B. E. Sobel Attenuation of Neointimal Vascular Smooth Muscle Cellularity in Atheroma by Plasminogen Activator Inhibitor Type 1 (PAI-1) J. Histochem. Cytochem., August 1, 2004; 52(8): 1091 - 1099. [Abstract] [Full Text] [PDF]

				K. S. Meir and E. Leitersdorf Atherosclerosis in the Apolipoprotein E-Deficient Mouse: A Decade of Progress Arterioscler Thromb Vasc Biol, June 1, 2004; 24(6): 1006 - 1014. [Abstract] [Full Text] [PDF]

				A. E. Cozen, H. Moriwaki, M. Kremen, M. B. DeYoung, H. L. Dichek, K. I. Slezicki, S. G. Young, M. Veniant, and D. A. Dichek Macrophage-Targeted Overexpression of Urokinase Causes Accelerated Atherosclerosis, Coronary Artery Occlusions, and Premature Death Circulation, May 4, 2004; 109(17): 2129 - 2135. [Abstract] [Full Text] [PDF]

				B. E. Sobel, D. J. Taatjes, and D. J. Schneider Intramural Plasminogen Activator Inhibitor Type-1 and Coronary Atherosclerosis Arterioscler Thromb Vasc Biol, November 1, 2003; 23(11): 1979 - 1989. [Abstract] [Full Text] [PDF]

				D. G. Grenache, T. Coleman, C. F. Semenkovich, S. A. Santoro, and M. M. Zutter {alpha}2{beta}1 Integrin and Development of Atherosclerosis in a Mouse Model: Assessment of Risk Arterioscler Thromb Vasc Biol, November 1, 2003; 23(11): 2104 - 2109. [Abstract] [Full Text] [PDF]

				K. Schafer, K. Muller, A. Hecke, E. Mounier, J. Goebel, D. J. Loskutoff, and S. Konstantinides Enhanced Thrombosis in Atherosclerosis-Prone Mice Is Associated With Increased Arterial Expression of Plasminogen Activator Inhibitor-1 Arterioscler Thromb Vasc Biol, November 1, 2003; 23(11): 2097 - 2103. [Abstract] [Full Text] [PDF]

				I. Bot, J. H. von der Thusen, M. M.P.C. Donners, A. Lucas, M. L. Fekkes, S. C.A. de Jager, J. Kuiper, M. J.A.P. Daemen, T. J.C. van Berkel, S. Heeneman, et al. Serine Protease Inhibitor Serp-1 Strongly Impairs Atherosclerotic Lesion Formation and Induces a Stable Plaque Phenotype in ApoE-/- Mice Circ. Res., September 5, 2003; 93(5): 464 - 471. [Abstract] [Full Text] [PDF]

				Y. Matsui, S. R. Rittling, H. Okamoto, M. Inobe, N. Jia, T. Shimizu, M. Akino, T. Sugawara, J. Morimoto, C. Kimura, et al. Osteopontin Deficiency Attenuates Atherosclerosis in Female Apolipoprotein E-Deficient Mice Arterioscler Thromb Vasc Biol, June 1, 2003; 23(6): 1029 - 1034. [Abstract] [Full Text] [PDF]

				E. Dai, H. Guan, L. Liu, S. Little, G. McFadden, S. Vaziri, H. Cao, I. A. Ivanova, L. Bocksch, and A. Lucas Serp-1, a Viral Anti-inflammatory Serpin, Regulates Cellular Serine Proteinase and Serpin Responses to Vascular Injury J. Biol. Chem., May 9, 2003; 278(20): 18563 - 18572. [Abstract] [Full Text] [PDF]

				G. G. Deng, B. Martin-McNulty, D. A. Sukovich, A. Freay, M. Halks-Miller, T. Thinnes, D. J. Loskutoff, P. Carmeliet, W. P. Dole, and Y.-X. Wang Urokinase-Type Plasminogen Activator Plays a Critical Role in Angiotensin II-Induced Abdominal Aortic Aneurysm Circ. Res., March 21, 2003; 92(5): 510 - 517. [Abstract] [Full Text] [PDF]

				A. T. Askari, M.-L. Brennan, X. Zhou, J. Drinko, A. Morehead, J. D. Thomas, E. J. Topol, S. L. Hazen, and M. S. Penn Myeloperoxidase and Plasminogen Activator Inhibitor 1 Play a Central Role in Ventricular Remodeling after Myocardial Infarction J. Exp. Med., March 3, 2003; 197(5): 615 - 624. [Abstract] [Full Text] [PDF]

				R. van Haperen, M. de Waard, E. van Deel, B. Mees, M. Kutryk, T. van Aken, J. Hamming, F. Grosveld, D. J. Duncker, and R. de Crom Reduction of Blood Pressure, Plasma Cholesterol, and Atherosclerosis by Elevated Endothelial Nitric Oxide J. Biol. Chem., December 6, 2002; 277(50): 48803 - 48807. [Abstract] [Full Text] [PDF]

				V. de Waard, E. K. Arkenbout, P. Carmeliet, V. Lindner, and H. Pannekoek Plasminogen Activator Inhibitor 1 and Vitronectin Protect Against Stenosis in a Murine Carotid Artery Ligation Model Arterioscler Thromb Vasc Biol, December 1, 2002; 22(12): 1978 - 1983. [Abstract] [Full Text] [PDF]

				A. Luttun, F. Lupu, E. Storkebaum, M. F. Hoylaerts, L. Moons, J. Crawley, F. Bono, A. R. Poole, P. Tipping, J.-M. Herbert, et al. Lack of Plasminogen Activator Inhibitor-1 Promotes Growth and Abnormal Matrix Remodeling of Advanced Atherosclerotic Plaques in Apolipoprotein E-Deficient Mice Arterioscler Thromb Vasc Biol, March 1, 2002; 22(3): 499 - 505. [Abstract] [Full Text] [PDF]

				A. Braun, B. L. Trigatti, M. J. Post, K. Sato, M. Simons, J. M. Edelberg, R. D. Rosenberg, M. Schrenzel, and M. Krieger Loss of SR-BI Expression Leads to the Early Onset of Occlusive Atherosclerotic Coronary Artery Disease, Spontaneous Myocardial Infarctions, Severe Cardiac Dysfunction, and Premature Death in Apolipoprotein E-Deficient Mice Circ. Res., February 22, 2002; 90(3): 270 - 276. [Abstract] [Full Text] [PDF]

				M. B. DeYoung, C. Tom, and D. A. Dichek Plasminogen Activator Inhibitor Type 1 Increases Neointima Formation in Balloon-Injured Rat Carotid Arteries Circulation, October 16, 2001; 104(16): 1972 - 1971. [Abstract] [Full Text] [PDF]

				Y. Zhu, P. M. Farrehi, and W. P. Fay Plasminogen Activator Inhibitor Type 1 Enhances Neointima Formation After Oxidative Vascular Injury in Atherosclerosis-Prone Mice Circulation, June 26, 2001; 103(25): 3105 - 3110. [Abstract] [Full Text] [PDF]

				P. M. Spooner, C. Albert, E. J. Benjamin, R. Boineau, R. C. Elston, A. L. George Jr, X. Jouven, L. H. Kuller, J. W. MacCluer, E. Marban, et al. Sudden Cardiac Death, Genes, and Arrhythmogenesis : Consideration of New Population and Mechanistic Approaches From a National Heart, Lung, and Blood Institute Workshop, Part II Circulation, May 22, 2001; 103(20): 2447 - 2452. [Abstract] [Full Text] [PDF]

				B. Venugopal, R. Sharon, R. Abramovitz, A. Khasin, and R. Miskin Plasminogen activator inhibitor-1 in cardiovascular cells: rapid induction after injecting mice with kainate or adrenergic agents Cardiovasc Res, February 1, 2001; 49(2): 476 - 483. [Abstract] [Full Text] [PDF]

				V. A. Ploplis, I. Cornelissen, M. J. Sandoval-Cooper, L. Weeks, F. A. Noria, and F. J. Castellino Remodeling of the Vessel Wall after Copper-Induced Injury Is Highly Attenuated in Mice with a Total Deficiency of Plasminogen Activator Inhibitor-1 Am. J. Pathol., January 1, 2001; 158(1): 107 - 117. [Abstract] [Full Text] [PDF]

				D. T. Eitzman, R. J. Westrick, Z. Xu, J. Tyson, and D. Ginsburg Plasminogen activator inhibitor-1 deficiency protects against atherosclerosis progression in the mouse carotid artery Blood, December 15, 2000; 96(13): 4212 - 4215. [Abstract] [Full Text] [PDF]

				J. W. Knowles and N. Maeda Genetic Modifiers of Atherosclerosis in Mice Arterioscler Thromb Vasc Biol, November 1, 2000; 20(11): 2336 - 2345. [Abstract] [Full Text] [PDF]

				D. C Felmeden and G. Y. Lip The renin-angiotensin-aldosterone system and fibrinolysis Journal of Renin-Angiotensin-Aldosterone System, September 1, 2000; 1(3): 240 - 244. [PDF]

				A. Braun, B. L. Trigatti, M. J. Post, K. Sato, M. Simons, J. M. Edelberg, R. D. Rosenberg, M. Schrenzel, and M. Krieger Loss of SR-BI Expression Leads to the Early Onset of Occlusive Atherosclerotic Coronary Artery Disease, Spontaneous Myocardial Infarctions, Severe Cardiac Dysfunction, and Premature Death in Apolipoprotein E-Deficient Mice Circ. Res., February 22, 2002; 90(3): 270 - 276. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sjöland, H. Articles by Ginsburg, D. Search for Related Content PubMed PubMed Citation Articles by Sjöland, H. Articles by Ginsburg, D. Related Collections Animal models of human disease Pathophysiology Genetically altered mice Fibrinolysis Mechanism of atherosclerosis/growth factors