The relationship of mutations in the MTHFR, prothrombin, and PAI-1 genes to plasma levels of homocysteine, prothrombin, and PAI-1 in children and adults.

Studies in adults have demonstrated that the genetic mutations C677T methylenetetrahydrofolate reductase (MTHFR), prothrombin 20210A, and the 4G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene are associated with elevated plasma levels of homocysteine. prothrombin and PAI-1, respectively and with an increased risk of thrombosis. No similar data is available in children. Therefore, we assessed the relationship of plasma levels of homocysteine, prothrombin and PAI-1 with their respective mutations in 197 normal children, compared to 40 adults. By stepwise multiple regression, homocysteine was positively associated with age, PAI-1 activity was negatively associated with age, while PAI-1 antigen and prothrombin levels were associated with gender, being higher in girls than boys. When the genotypes were added to the regression model as additional explanatory variables, the MTHFR genotype accounted for 2.9% of the variance of homocysteine (p = 0.024), and the PAI-1 gene accounted for 2.7% of the variance of PAI-1 antigen levels (p = 0.023). Of children homozygous for the MTHFR mutation, 35% had homocysteine levels > or = the age-specific 95th percentile, compared to 2% heterozygotes and 5% wild type normals (p = 0.0001). The mean homocysteine level was higher in children homozygous for the MTHFR gene (8.4 micromol/1) than in heterozygotes (5.5 micromol/l), p <0.05. Of children homozygous for the 4G polymorphism of the PAI-1 gene, 19% had PAI-1 activity levels > or = the age-specific 95th percentile, compared to 2% of heterozygotes and 3% of wild type normals (p = 0.003). Studies of the incidence of the MTHFR, prothrombin, and PAI-1 4G/5G genotypes in children with thrombosis, when compared to these healthy normals, will provide evidence as to which of these genes are associated with thrombophilia.

Heritable thrombophilia and hypofibrinolysis. Possible causes of retinal vein occlusion.

OBJECTIVE: To determine whether heritable thrombophilia and hypofibrinolysis were risk factors for retinal vein occlusion. DESIGN: Measures of thrombophilia (increased likelihood of thrombus formation) included anticardiolipin antibodies (IgG and IgM), the lupus anticoagulant (including dilute Russell viper venom clotting time), antigenic proteins C and S, and homocysteine. Polymerase chain reaction assays were performed for 3 thrombophilic gene mutations (factor V Leiden, methylenetetra-hydrofolate reductase, and prothrombin gene). Measures of hypofibrinolysis (reduced ability to lyse thrombi) included lipoprotein Lp(a), plasminogen activator inhibitor activity, and polymerase chain reaction analysis of the hypofibrinolytic 4G/5G polymorphism of the PAI1 gene. These coagulation measures were performed in 17 patients with retinal vein occlusions with comparison with serologic coagulation measures and polymerase chain reaction assays in 40 and 234 healthy normal volunteers as controls, respectively. RESULTS: Of 14 patients with retinal vein occlusion with measures of dilute Russell viper venom clotting time, a thrombophilic antiphospholipid antibody, 6 (43%) had abnormal results (> 38.8 seconds) compared with 1 (3%) of 30 controls (P = .002). Of 17 patients with vein occlusion, 3 (18%) were heterozygous for the thrombophilic factor V Leiden G1691A mutation compared with 7 (3%) of 233 controls (P = .02). Of 17 patients with vein occlusion, 2 (12%) had normal alleles (5G/5G) for the plasminogen activator inhibitor gene promoter; the other 15 (88%) were heterozygous or homozygous for the 4G polymorphism, which is associated with hypofibrinolysis. Of 234 controls, 85 (36.3%) had the 5G/5G allele; 149 (63.7%) were heterozygous or homozygous for the 4G polymorphism (P = .03). Patients with vein occlusion were more likely to have high levels of the major determinant of hypofibrinolysis, plasminogen activator inhibitor activity. These levels were high (> 22 U/L) in 6 (38%) of 16 patients with vein occlusion compared with 1 (2%) of 40 controls (chi 2 = 12.8; P = .001). Patients with vein occlusion were more likely (8/16 [50%]) to have high levels of hypofibrinolytic Lp(a) (> 35 mg/dL) than controls (5/40 [13%]; chi 2 = 9; P = .003). The median Lp(a) level in patients with vein occlusion who had the 4G/4G genotype was 62 mg/dL compared with 5.3 mg/dL in controls with the 4G/4G genotype (P = .05). CONCLUSION: Thrombophilia and hypofibrinolysis are possible causes of retinal vein occlusion.

The plasminogen activator inhibitor-1 gene, hypofibrinolysis, and osteonecrosis.

In 59 patients with osteonecrosis of the hip, four genes associated with thrombophilia or hypofibrinolysis along with coagulation tests were studied to determine the pathoetiologic associations of heritable coagulation disorders with osteonecrosis. Patients did not differ from healthy control subjects for the thrombophilic Factor V Leiden, prothrombin, or methylenetetrahydrofolate reductase mutations. The plasminogen activator inhibitor-1 gene was shifted toward homozygosity for the 4G polymorphism; 41% of patients with osteonecrosis were homozygous for the 4G/4G polymorphism versus 20% of 40 healthy control subjects. The gene product of the 4G polymorphism, hypofibrinolytic plasminogen activator inhibitor activity, was higher in patients than in control subjects (median 19.2 versus 6.3 U/mL); 61% of patients had high plasminogen activator inhibitor activity (> or = 16.4 U/mL) versus 5% of control subjects. Stimulated tissue plasminogen activator activity (inhibited by plasminogen activator inhibitor activity) was lower in patients than in control subjects (3.10 versus 5.98 IU/mL); 31% of patients had low stimulated tissue plasminogen activator activity (< 2.28 IU/mL) versus 3% of control subjects. Heritable hypofibrinolysis conferred by the 4G/4G mutation of the plasminogen activator inhibitor-1 gene seems to be a major pathoetiology of primary osteonecrosis.

Sensitivity, specificity and predictive value of modified assays for activated protein C resistance in children.

Very little data is available assessing the clinical utility of coagulation-based APC resistance assays compared to DNA-based analysis for the factor V Leiden mutation in children. Therefore, the clinical utility of four aPTT-based assays for APC resistance was evaluated in 169 children, ages 3 months through 16 years. The prevalence of the Arg506 to Gln mutation was 7/169 (4.1%). Using cutoff points derived from the normal PCR-screened population (n = 162), two assays for APC resistance (APC-SR and n-APC-SR) gave poor concordance with the PCR assay (sensitivity 29% and 57%, respectively). Two modified assays (FDAPC-SR and n-FDAPC-SR), in which patient plasma was prediluted 1:5 in factor V deficient plasma, gave excellent concordance (sensitivity 100%). The predictive value of a positive test was 0.25, 0.44, 1.00 and 0.88 for the APC-SR, n-APC-SR, FDAPC-SR and n-FDAPC-SR, respectively. The FDAPC-SR and n-FDAPC-SR tests gave excellent discrimination using cutoff values derived from the total population (n = 169) without regard to previous PCR screening results.

Resistance to activated protein C and Legg-Perthes disease.

Thrombophilia may cause thrombotic venous occlusion in the femoral head, with venous hypertension and hypoxic bone death, leading to Legg-Perthes disease. Resistance to activated protein C, the most common thrombophilic trait, was measured in 64 children with Legg-Perthes disease. Genomic deoxyribonucleic acid was studied to delineate the CGA-->CAA substitution at position 1691 of the Factor V Leiden gene responsible for resistance to activated protein C. The activated protein C ratio was calculated by dividing clotting time obtained with activated protein C-calcium chloride by clotting time obtained with calcium chloride alone. Resistance to activated protein C, with a low activated protein C ratio (less than 2.19, the 5th percentile for 160 normal pediatric controls) was the most common coagulation defect, found in 23 of 64 children with Legg-Perthes disease versus 7 of 160 pediatric controls. Eight of 64 children with Legg-Perthes disease had a low activated protein C ratio and the mutant Factor V gene (7 heterozygotes, 1 homozygote) versus 1 of 101 normal pediatric controls. Two or 3 generation vertical and horizontal transmission of heterozygosity for the mutant Factor V gene was found in 4 of the 8 kindreds. Of 64 children with Legg-Perthes disease, only 14 (22%) had entirely normal coagulation measures. Resistance to activated protein C appears to be a pathogenetic cause of Legg-Perthes disease.

Thrombophilia and hypofibrinolysis: pathophysiologies of osteonecrosis.

In 31 patients with osteonecrosis (primarily of the hip), 74% had 1 or more primary coagulation disorders. In 18 patients, 15 (83%) who had coagulation disorders, the osteonecrosis was initially identified as idiopathic and was not associated with known underlying drugs (glucocorticoids) or diseases (alcoholism, sickle cell disease, Gaucher's disease). In 13 patients, 8 (62 %) who had coagulation disorders, the osteonecrosis was initially identified as secondary, and was associated with glucocorticoids in 12 patients, and with alcoholism in 1. The coagulation disorders included thrombhophilia (increased tendency to intravascular thrombosis) and hypofibrinolysis (reduced ability to lyse thrombi). Of the 18 patients initially thought to have idiopathic osteonecrosis, thrombophilia alone was found in 12% (resistance to activated protein C in 6%, low protein C in 6%), hypofibrinolysis alone was found in 50% (high lipoprotein(a) in 44%, low stimulated tissue plasminogen activator activity was found in 6%), and mixed thrombophilia hypofibrinolysis was found in 22%. Resistance to activated protein C was more common in these 18 patients than in healthy controls (11% versus 0%), as was high lipoprotein(a) (67% versus 20%). Of the 13 patients with secondary osteonecrosis, thrombophilia alone was found in 8% (low protein C), hypofibrinolysis alone was found in 30% (high Lp(a) in 15%, low tissue plasminogen activator activity in 15%), and mixed thrombophilia hypofibrinolysis was found in 23%. Low tissue plasminogen activator activity was more common in the 13 patients with secondary osteonecrosis than in controls (27% versus 7%), as was low protein C (23% versus 0%). In aggregate, these findings lead us to the speculation that primary, heritable thrombophilia or hypofibrinolysis causes thrombotic venous occlusion in the head of the femur, leading to venous hypertension and hypoxic death of bone (osteonecrosis).

Measurement of lipoprotein (a): comparison of Macra and Imubind methods.

Our specific aim was to compare lipoprotein(a) [Lp(a)] measured by two enzyme-linked immunosorbent assays (the Strategic Diagnostics, Inc. Macra Lp(a) and the American Diagnostica, Inc. Imubind Lp(a) Stripwell) in sequentially referred hyperlipidemic patients. The Macra method binds Lp(a) in serum or plasma to monoclonal anti-Lp(a) in microtiter test wells followed by polyclonal anti-Lp(a) and a chromogenic reaction; the Imubind method is similar but uses two polyclonal anti-Lp(a) antibodies. Within run coefficients of variation were 1.5 percent for the Macra (Lp[a] 27.2 +/- 0.4 mg/dl) and 3.4 percent for the Imubind method (Lp[a] = 18.9 +/- 0.6 mg/dl). Between-run coefficients of variation for the Macra method were 4.7 percent (Lp[a] 14.8 +/- 0.7 mg/dl) and 8.3 percent (Lp[a] of 33.5 +/- 2.8 mg/dl). For the Imubind method in nine separate analytical runs, the between run coefficients of variation were 8.4 percent (Lp[a] of 15.4 +/- 1.3 mg/dl), 3.0 percent (18.8 +/- 0.6 mg/dl), and 5.7 percent (25.6 +/- 1.5 mg/dl). The intraclass correlation was 0.92 (p < or = 0.0001) for duplicate aliquots (n = 210) quantitated by both methods, and the lower limit of the 95 percent confidence interval of the intraclass correlation was 0.90. Comparison of the two methods revealed no systematic bias (p = 0.09), since the lower limit of the 95 percent intraclass correlation confidence interval was > or = 0.75, the two methods for measuring Lp(a) are considered interchangeable. Given the importance of Lp(a) as an independent risk factor for coronary heart disease, it is clinically important to have precise and accurate methods for its measurement.

Thrombophilia, hypofibrinolysis, and alveolar osteonecrosis of the jaws.

OBJECTIVES: Our specific aim in 49 patients (42 women, 7 men) with osteonecrosis of the jaw was to determine whether thrombophilia (increased tendency to intravascular thrombosis) or hypofibrinolysis (reduced ability to lyse thrombi) were associated with this regional avascular necrosis. STUDY DESIGN: Determinants of thrombosis and fibrinolysis were compared in healthy controls and in 42 women and 7 men who had biopsy-proven idiopathic osteonecrosis of the jaw with severe chronic jaw or facial pain syndromes and failure to respond to conventional medical and dental treatments. RESULTS: Of the 49 patients, 35 (71%) had thrombophilia or hypofibrinolysis and only 14 were normal. Thrombophilia as a sole coagulation defect was found in 10 patients, 7 with resistance to activated protein C and 3 with low protein C (deficiency of an antithrombotic protein). Hypofibrinolysis with low stimulated tissue plasminogen activator activity and high lipoprotein (a) (an atherogenic, hypofibrinolytic lipoprotein) were found as sole coagulation defects in seven and eight patients, respectively. Ten patients had mixed defects; 7 of these 10 had thrombophilia with resistance to activated protein C. Sinusoidal dilatation was a constant feature in maxillary and mandibular bone biopsies, suggesting venous occlusion with intramedullary hypertension. Marrow fibrosis and occasional fibrin plugs were additional microscopic features believed to impair venous drainage and to contribute to ischemic necrosis of the alveolar bone. CONCLUSIONS: Primary thrombophilia and hypofibrinolysis appear to be common, heritable, pathophysiologic risk factors for idiopathic osteonecrosis of the jaws. These coagulation defects may also contribute to alveolar neuralgia, atypical odontalgia and facial neuralgia, idiopathic trigeminal neuralgia, and to treatment failures so often encountered in patients with alveolar osteonecrosis and disabling chronic facial and jawbone pain syndromes.

Association of antithrombotic factor deficiencies and hypofibrinolysis with Legg-Perthes disease.

Thirty-three (75 per cent) of forty-four unselected children who had Legg-Perthes disease were found to have coagulation abnormalities. Twenty-three children had thrombophilia (a deficiency in antithrombotic factor C or S, with an increased tendency toward thrombosis); nineteen of the twenty-three children had protein-C deficiency and four had protein-S deficiency. Seven children had a high level (0.25 gram per liter or more) of lipoprotein(a), a thrombogenic, atherogenic lipoprotein associated with osteonecrosis in adults. Three children had hypofibrinolysis (a reduced ability to lyse clots). The mean age of the children when the Legg-Perthes disease was first diagnosed was 5.8 +/- 2.7 years, and the mean age at the time of the present study was 10.1 +/- 4.4 years. At least one of the first-degree relatives of eleven of the nineteen probands who had a low protein-C level had a low protein-C level as well; all of these low levels represented previously undiagnosed familial protein-C deficiency. The eleven probands who had familial protein-C deficiency were more likely to have early onset of Legg-Perthes disease (at or before the age of five years) than the eleven children who had normal levels of protein C, protein S, and lipoprotein(a) as well as normal fibrinolytic activity (chi-square = 6.6; p = 0.01). At least one first-degree relative of one of the four probands who had a low protein-S level had a low protein-S level and previously undiagnosed familial protein-S deficiency. At least one first-degree relative of six of the seven probands who had a high level of lipoprotein(a) had a familial high level of lipoprotein(a). Six of the seven children who had a high level of lipoprotein(a) also had a low level of stimulated tissue-plasminogen activator activity, the major initiator of fibrinolysis. At least one first-degree relative of one of the three probands who had normal levels of protein C, protein S, and lipoprotein(a) but low stimulated tissue-plasminogen activator activity also had low stimulated tissue-plasminogen activator activity (familial hypofibrinolysis). Legg-Perthes disease, thrombophlebitis, premature myocardial infarction, and stroke, which are ramifications of the familial thrombophilic-hypofibrinolytic disorders, were common in the first and second-degree relatives of the thirty-three children with Legg-Perthes disease who also had thrombophilic-hypofibrinolytic disorders.

Idiopathic osteonecrosis, hypofibrinolysis, high plasminogen activator inhibitor, high lipoprotein(a), and therapy with Stanozolol.

In five patients with idiopathic osteonecrosis (ON) of the hip, four having hypofibrinolysis mediated by high plasminogen activator inhibitor (PAI-Fx), and one with high Lp(a), our specific aim was to determine whether therapy (Rx) with the anabolic-androgenic steroid, Stanozolol (6 mg/day), would normalize PAI-Fx and Lp(a) and thus potentially ameliorate ON. Prior to Rx, none of the four patients with high PAI-Fx could normally elevate tissue plasminogen activator (tPA-Fx) after 10 min venous occlusion at 100 mm Hg. After 12-18 weeks on Rx, PAI-Fx and stimulated tPA-Fx normalized in all four patients. Prior to Rx, mean (SD) stimulated tPA-Fx was low, 0.4 +/- 0.3 IU/ml (lower limit of normal 2.28 IU/ml). On Rx, stimulated tPA-Fx normalized, rising to 2.83 +/- 1.9 IU/ml, P = .004. Prior to Rx, mean (SD) basal PAI-Fx was high, 99 +/- 68 (upper limit of normal 26.9 U/ml), and fell on Rx to 22.5 +/- 22, P = .004. In two of the five patients normalization of hypofibrinolysis or high Lp(a) was accompanied by major symptomatic improvement. Prior to Rx, and 2 years after onset of unilateral hip pain, one of the four patients with high PAI-Fx and low stimulated tPA-Fx could walk only one block painfully. After 8 weeks on Stanozolol Rx, and continuing through 54 weeks on Rx, he walked 2 miles per day without pain, despite radiographic progression of ON. In three of the four patients with high PAI and with osteonecrosis present 0.3, 2, and 6 years prior to Stanozolol Rx, there was no clinical improvement after 14-156 weeks of Rx despite normalization of stimulated tPA-Fx and PAI-Fx. The fifth patient, 1 month after onset of disabling hip pain, had normal PAI-Fx but high Lp(a) (27 mg/dl), and MRI evidence of bone marrow edema ("transient osteoporosis").(ABSTRACT TRUNCATED AT 250 WORDS)

Hypofibrinolytic and atherogenic risk factors for stroke.

In 87 patients (studied on average 1 year after their strokes) and 26 of their first-degree relatives, our specific aim was to assess the prevalence of the following stroke risk factors: hypofibrinolysis, familial hypofibrinolysis, high lipoprotein (a) level, and dyslipidemia. At least 2 months after their strokes (primarily ischemic), 87 patients had measures of lipids and lipoprotein (a); 69 and 67 patients had measures of basal and stimulated fibrinolytic activity, respectively, four new findings were as follows. (1) Hypofibrinolysis was common, with bottom decile-stimulated tissue plasminogen activator activity (the major stimulator of fibrinolysis) in 21% of stroke probands and in 30% of their first-degree relatives, versus 7% of 29 nomolipidemic control subjects (p = 0.09 and 0.026, respectively). (2) The hypofibrinolysis was mediated by top-decile levels of basal plasminogen activator inhibitor activity (the major inhibitor of fibrinolysis), which were observed in 20% of stroke probands and in 21% of their first-degree relatives, versus 8% of 175 nomolipidemic control subjects (p = 0.007 and 0.04, respectively). Mean (SD) basal plasminogen activator inhibitor activity and antigen level were higher in stroke probands (18 +/- 18 U/ml and 35 +/- 31 ng/ml, respectively) than in the 175 normolipemic control subjects (14 +/- 10 [p = 0.002], 28 +/- 34 [p = 0.016]). (3) Levels of basal tissue plasminogen activator antigen, a probable marker for atherosclerosis, were much higher in stroke probands than in the 175 normolipemic control subjects (15 +/- 7.3 ng/ml vs 7 +/- 3.8, p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of plasminogen activator inhibitor type 1 antigen: comparison of Tintelize and Imubind methods.

Our specific aim was to compare three plasminogen activator-inhibitor type 1 (PAI-1) antigen ELISA kit assays (the Biopool AB, Ltd, TintElize PAI-1 Strip-Well Format; the American Diagnostica, Inc., Imubind 822/1; and the second generation Imubind 822/1S). Within-run coefficients of variation (n = 6) for the TintElize, Imubind 822/1 and Imubind 822/1S methods were 5.5%, 5.9% and 6.8%, respectively. Between-run coefficients of variation for six aliquots per run were 2.9% for TintElize, 3.8% for Imubind 822/1, and 3.5% for Imubind 822/1S. Comparison of the average of duplicate aliquots from hyperlipidaemic patients demonstrated intraclass correlations of 0.75, 0.79 and 0.95 for TintElize vs Imubind 822/1 (n = 39), TintElize vs Imubind 822/1S (n = 39), and Imubind 822/1 vs 822/1S (n = 84), respectively. Lower 95% confidence interval limits of the intraclass correlation were 0.55, 0.48 and 0.93, respectively. Mean PAI-1 antigen values (n = 39) were 12.1, 15.8, 15.8 and 16.0 ng/ml, respectively, for TintElize, TintElize without using the quenching well, Imubind 822/1, and Imubind 822/1S. All three methods were easily performed and exhibited high correlation and reproducibility. A significant systematic bias (P < 0.006) existed between TintElize and TintElize without using the quenching well, Imubind 822/1, and Imubind 822/1S. However, there was no significant bias when TintElize without using the quenching well is compared with Imubind 822/1 (P > 0.8) and to 822/1S (P > 0.8) nor is there significant systematic bias between Imubind 822/1 and 822/1S (P > 0.3). By convention, interchangeability between assay methods suggests that the lower limit of the 95% intraclass correlation confidence interval be greater than 0.75.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the Abbott Cell Dyn 3000 SL and the Coulter STKS hematology analyzers.

A side by side comparison of the Cell Dyn 3000 SL and Coulter STKS using identical samples was performed over a four month period in the Clinical Hematology Laboratory at the University of Cincinnati Medical Center. A total of 444 samples comprised of 114 sophomore medical students and 330 randomly selected clinical patients were compared in 20 hemogram parameters, and the ability of each instrument to generate differential suspect flags was analyzed. Correlation coefficients for leukocytes, erythrocytes, hemoglobin, hematocrit, and platelets were 0.99. Correlation coefficients for the Cell Dyn and STKS compared with a 600 cell manual differential were 0.98 and 0.89 for neutrophils, 0.96 and 0.87 for lymphocytes, and 0.72 and 0.48 for monocytes, respectively. Both instruments demonstrated high precision and accuracy by internal and external quality control standards. Each analyzer exhibited strength as a screening instrument for abnormal cell populations. The Coulter STKS had overall sensitivity of 75%, specificity of 94%, 25% false negatives, and 6% false positives. Sensitivity, specificity, false negative and positive rates for the Cell Dyn 3000 SL were 68%, 92%, 32%, and 8%, respectively. Based upon this extensive side by side comparison using an identical sample population, it has been concluded that although statistically significant systematic bias (p < 0.05) exists between the two instruments, both analyzers can adequately support the needs of the clinical hematology laboratory.

Beta blockers, Lp(a), hypertension, and reduced basal fibrinolytic activity.

To assess the hypothesis that beta blocker use and hypertension are associated with high lipoprotein(a) [Lp(a)] or with reduced basal fibrinolytic activity, the authors studied relationships of hypertension and beta blockers to Lp(a), lipids, lipoproteins, apolipoproteins, and basal fibrinolytic activity in 385 patients consecutively referred for diagnosis and therapy of hyperlipidemia. A second aim was to determine possible gender differences in fibrinolytic activity among patients with hypertension. Ninety-nine patients (58 women [88% post-menopausal] and 41 men) had drug-treated hypertension. In women, hypertension was a positive, independent predictor of the major inhibitors of fibrinolysis, plasminogen activator inhibitor antigen (p = 0.017), and plasminogen activator inhibitor activity (p = 0.004). In men and women, major risk factors for atherosclerosis were significant, independent predictors of reduced basal fibrinolysis. Median Lp(a) in the 99 patients with hypertension (16 mg/dL) did not differ from Lp(a) (18 mg/dL) in normotensive patients (p > 0.1). Of the 385 patients, the 39 beta blocker users had higher plasminogen activator inhibitor activity (p = 0.01), higher triglyceride (p = 0.02) levels, and higher Quetelet Indices (p = 0.01) than non-users (n = 346). After covariance adjusting for age, Quetelet Indices, sex, and triglycerides, plasminogen activator inhibitor activity was not higher in beta blocker users than in non-users (p > 0.1). Median Lp(a) did not differ in beta blocker users (16 mg/dL) and in non-users (17 mg/dL), p greater than 0.1. Hypertensive, predominantly post-menopausal women are likely to have high plasminogen activator inhibitor activity and plasminogen activator inhibitor antigen with concurrent reduced fibrinolytic activity, as well as high fibrinogen levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein C and S deficiency, thrombophilia, and hypofibrinolysis: pathophysiologic causes of Legg-Perthes disease.

In eight patients with Legg-Perthes disease, we assessed the etiologic roles of thrombophilia caused by protein C and protein S deficiency and hypofibrinolysis mediated by low levels of tissue plasminogen activator activity. We speculated that thrombosis or hypofibrinolysis were common causes of Legg-Perthes disease. Three of the eight patients had protein C deficiency; they came from kindreds with previously undiagnosed protein C deficiency. In one of these three kindreds there were six protein C-deficient family members (beyond the proband child), four of whom had thrombotic events as adults. One of the eight patients had protein S deficiency, as did his brother who had sustained mesenteric vein thrombosis at age 43. One of the eight patients who had normal proteins C, S, and antithrombin III had hypofibrinolysis, failing to elevate tissue plasminogen activator activity after 10 min of venous occlusion at 100 mm Hg. Plasminogen activator inhibitor, alpha 2-antiplasmin, and fibrinogen values were normal in all eight patients. Beyond their Legg-Perthes disease, none of the eight patients had evidence for venous thrombosis. Of the eight patients, four had thrombophilia and one had hypofibrinolysis, disorders that we believe contributed to thrombotic venous occlusion of the femur with subsequent venous hypertension and bone death that characterize Legg-Perthes disease.

Hypofibrinolysis: a common, major cause of osteonecrosis.

In 30 patients with osteonecrosis of the hip (12 idiopathic, 18 secondary), we assessed the role of hypofibrinolysis mediated by high levels of plasminogen activator inhibitor (PAI). We evaluated hypofibrinolysis as a common, potentially reversible, pathophysiologic cause of idiopathic osteonecrosis. In all 18 patients with secondary osteonecrosis, PAI was normal, as was the ability to activate fibrinolysis. Nine of the 12 patients with idiopathic osteonecrosis had exceptionally high PAI levels and could not normally elevate tissue plasminogen activator (tPA-Fx), the major stimulator of fibrinolysis, after 10 min of venous occlusion at 100 mm Hg. The group of 12 patients with idiopathic osteonecrosis, compared to the 18 with secondary osteonecrosis, had low mean stimulated tPA-Fx (1.92 vs. 7.6 IU/ml, P < or = .001) and very high stimulated PAI-Fx (70 vs. 7.6 U/ml, P < or = .01). Three of the 12 patients with idiopathic osteonecrosis had both normal PAI and normal stimulated tPA-Fx. These three patients and 14 of the 18 with secondary osteonecrosis had high lipoprotein (a) [Lp(a)] (> 20 mg/dl). Mean Lp(a) was much higher (60 mg/dl) in the patients with secondary osteonecrosis than Lp(a) (16 mg/dl, P < or = .001) in the 12 patients with idiopathic osteonecrosis. These findings suggest that hypofibrinolysis mediated by high PAI is a common cause of idiopathic osteonecrosis, whereas high Lp(a) may play an etiologic role in secondary osteonecrosis. Prospective studies of patients with high PAI and/or high Lp(a) should be carried out to assess further their apparently causal roles in osteonecrosis.

Familial idiopathic osteonecrosis mediated by familial hypofibrinolysis with high levels of plasminogen activator inhibitor.

Familial hypofibrinolysis with 3 generation, autosomal dominant, very high levels of plasminogen activator inhibitor activity (PAI-Fx) and antigen (PAI-Ag) was etiologically associated with bilateral idiopathic osteonecrosis in 2 brothers. They, their mother, 2 brothers, sister, and all 4 of her children (none of whom had yet developed osteonecrosis), all had very high PAI and could not elevate tissue plasminogen activator after 10 minutes of venous occlusion at 100 mmHg. Familial high PAI levels with concurrent hypofibrinolysis co-segregated with familial combined hyperlipidemia, both being independent risk factors for premature coronary heart disease. If thrombi block venous drainage in the femur, familial hypofibrinolysis mediated by familial high PAI with inability to lyse thrombi would contribute to venous hypertension of bone, bone anoxia, and bone death characteristic of osteonecrosis.

Inheritance conjointly contributing to fibrinolysis and hyperlipidemia.

Our specific aim was to assess within-family relationships of basal fibrinolytic activity and its determinants in hyperlipidemic probands (n = 34) with high lipoprotein (a) [Lp(a)] levels (> 35 mg/dL) and their first-degree relatives (n = 74) and in hyperlipidemic probands (n = 19) with Lp(a) < 35 and their first-degree relatives (n = 23). Probands' plasminogen activator inhibitor activity (PAI-Fx), the major fibrinolysis inhibitor, correlated with first-degree relatives' PAI-Fx in high-Lp(a) kindreds (r = .30, P = .06) and in Lp(a) < 35 kindreds (r = .43, P < or = .05). Probands' tissue plasminogen activator activity (tPA-Fx), the major fibrinolysis activator, was inversely associated with first-degree relatives' PAI-Fx in high-Lp(a) kindreds (r = -.30, P = .06) and in Lp(a) < 35 kindreds (r = -.49, P < or = .025). These correlations [irrespective of probands' Lp(a)] pointed to within-family heritability of the major fibrinolysis inhibitor, PAI-Fx, and the fibrinolysis stimulator, tPA-Fx. There were many other within-family correlations. High-Lp(a) probands' tPA-Fx, the stimulator of fibrinolysis, correlated with first-degree relatives' tPA-Fx (r = .32, P < or = .05). High-Lp(a) probands' plasminogen was inversely correlated with first-degree relatives' alpha 2-antiplasmin, a major fibrinolytic inhibitor (r = -.41, P < or = .01), and with their Lp(a) [r = -.24, P < or = .05]. High-Lp(a) probands' tPA-Fx correlated inversely with first-degree relatives' apolipoprotein (apo) B (r = -.28) and triglyceride ([TG] r = -.41), and positively with their high-density lipoprotein cholesterol ([HDLC] r = .40) and apo A-1 (r = .33; all P < or = .025). High-Lp(a) probands' PAI-Fx correlated positively with first-degree relatives' apo B (r = .34) and TG (r = .47), and inversely with HDLC (r = -.34) and apo A-1 (r = -.30; all P < or = .01). By stepwise regression, the Quetelet index (a measure of relative ponderosity) was independently inversely associated with tPA-Fx (P < or = .05) and positively associated with tPA-Ag and PAI-Fx (P < or = .05). TG was a positive independent determinant of PAI-Fx (P < or = .05), alpha 2-antiplasmin (P < or = .05), and plasminogen (P < or = .05). Lp(a) was a positive, independent determinant of fibrinogen (P < or = .05).(ABSTRACT TRUNCATED AT 400 WORDS)

Endogenous testosterone, fibrinolysis, and coronary heart disease risk in hyperlipidemic men.

To assess relationships of endogenous testosterone with fibrinolysis and coronary heart disease risk factors in 55 newly referred hyperlipidemic men, we studied the relationships of testosterone to basal fibrinolytic activity, lipids, lipoproteins, and apolipoproteins. Testosterone correlated positively with the major stimulator of fibrinolysis, tissue plasminogen activator activity (r = 0.30; p = 0.02) and correlated inversely with two independent coronary heart disease risk factors, plasminogen activator inhibitor activity, the major fibrinolysis inhibitor (r = -0.33; p = 0.01), and fibrinogen (r = -0.39; p = 0.004). Testosterone correlated inversely with plasma triglycerides (r = -0.33; p = 0.01). Stepwise multiple regression was done with fibrinolytic activities as the dependent variables, and age, Quetelet Index (relative ponderosity), apolipoprotein A-I, apolipoprotein B, triglyceride, testosterone, time of blood sampling, and lipoprotein (a) as explanatory variables. Testosterone was an inverse, independent predictor of fibrinogen (p = 0.002); 53% of the variance of fibrinogen could be accounted for by age and triglyceride level (positive; p = 0.001, p = 0.01), and by apolipoprotein A-I and testosterone (negative; p = 0.02, p = 0.002). Testosterone was an independent inverse predictor of tissue plasminogen activator antigen (p = 0.0008), with tissue plasminogen activator antigen correlating inversely with tissue plasminogen activator activity. Quetelet index and apolipoprotein B were independent negative predictors of tissue plasminogen activator activity (p = 0.02, p = 0.03); Quetelet index and triglycerides were independent positive predictors of plasminogen activator inhibitor activity (p = .0001, p = .0001) and alpha 2-antiplasmin (p = 0.0003, p = 0.009).(ABSTRACT TRUNCATED AT 250 WORDS)