Graziella Saggiorato

Reduced fibrinolytic potential one year after kidney transplantation : relationship to long-term steroid treatment

Thromboembolic complications constitute an important risk in renal transplant patients, in whom a hypercoagulable state is associated with immunosuppressive treatment, and the presence of hypercoagulability and hypofibrinolysis specifically with cyclosporine. Hypercorticism secondary to steroid treatment has been associated with a thrombophilic state and the presence of a reduced fibrinolytic potential in particular. The aims of this study were to first evaluate the fibrinolytic potential by the venous occlusion (VO) test in 19 renal transplant (RT) patients, and then compare these findings with those obtained in similar groups of normal subjects and patients with Cushings disease. The following tests were carried out before and after the VO test: euglobulin lysis time and t-PA and PAI-1 activities and antigen. Compared with normal controls, RT and Cushings patients both showed a similar significant increase in PAI-1 activity and concentration. The VO test revealed a similar impairment in fibrinolytic potential in both the RT and Cushing groups. High and pathological PAI-1 levels before and after the VO test were consistent with a defective fibrinolytic potential due to the inhibitory effect of PAI-1 on plasminogen activation. A hypofibrinolytic state was found in 68.4% of RT patients. Our results suggest that an imbalance in the fibrinolytic system is a typical feature of RT patients one year after transplantation. Steroids appear to be the immunosuppressive drug mainly involved in determining thromboembolic risk after renal transplantation.

The PAI-I gene 4G/5G Polymorphism and Deep Vein Thrombosis in Patients with Inherited Thrombophilia

Genetic and acquired factors may influence phenotypic expression of inherited thrombophilia. Hypofibrinolysis due to excess PAI-I can be found in patients with deep vein thrombosis (DVT) and 4G/5G polymorphism of the PAI-1 gene may modulate the inhibitors synthesis. In 149 patients with inherited thrombophilia, the possible thrombotic contribution of both 4G/5G polymorphism and PAI-1 plasma levels was evaluated. Sixty-seven patients with idiopathic DVT and 98 normal subjects were also studied. By comparison with controls, a significantly higher prevalence of 4G/4G genotype was seen in idiopathic DVT and in thrombophilia patients, although in this latter group the difference only remained significant in cases symptomatic for thrombosis (p=0.01). The 4G/4G genotype was associated with a greater risk of thrombosis both in symptomatic thrombophilia patients (OR 2.85, 95% CI 1.26-6.46) and in idiopathic DVT patients (OR 3.1, 95% CI 1.26-7.59). The greater frequency of 4G allele in symptomatic thrombophilia patients with respect to controls was statistically significant (p=0.04). Compared to healthy subjects, PAI-i:Ag levels were higher in symptomatic thrombophilia patients and related to the 4G/5G polymorphism, with significantly higher values in the 4G/4G carriers. In conclusion, PAI-1 4G/5G polymorphism may influence PAI-i expression and thrombotic risk in patients with inherited thrombophilia.

Anti-β2-Glycoprotein I antibodies in patients with acute venous thromboembolism : Prevalence and association with recurrent thromboembolism

Abstract To establish the prevalence of antibodies against β 2 -glycoprotein I (β 2 GPI) in unselected patients with venous thromboembolism, as well as the association with antiphospholipid antibodies (aPL) and a history of previous thromboembolism, we investigated the presence of these antibodies in 227 consecutive patients with acute deep vein thrombosis or pulmonary embolism, of whom 63 were carriers of aPL with or without lupus anticoagulant (LA), and seven were carriers of LA alone. The presence of antibodies against β 2 GPI was demonstrated in 19 patients [8.4%; 95% confidence interval (CI), 4.5–11.3%]. All of them belonged to the group of 63 patients with aPL (30.2%). A history of a previous thromboembolism was identified in 11 of the 19 patients with anti-β 2 GPI antibodies (57.9%) and in 45 of the 208 patients without these antibodies [21.6%; odds ratio (OR)=4.98; 95% CI, 1.89–13.1; p 2 GPI antibodies (11 of 19, 57.9%) was significantly higher than that observed in patients without these antibodies (15 of 51, 29.4%; OR=3.3; 95% CI, 1.1–9.83; p =0.28). We conclude that in patients with acute venous thromboembolism the prevalence of antibodies against β 2 GPI is unexpectedly high. The presence of these antibodies seems to identify a subgroup of patients with antiphospholipid antibodies who have a peculiarly high risk of thrombotic recurrences. Further prospective studies are indicated to better define the role of anti-β 2 GPI antibodies in the development of recurrent thromboembolism.

Endothelial dysfunction in haemophilia patients

Summary.  Haemophilia patients may develop cardiovascular diseases, suggesting that their clotting defect does not protect them completely from atherosclerosis and its complications. We aimed to evaluate cardiovascular risk factors and, for the first time, the presence of endothelial dysfunction in middle‐aged haemophilia patients. We studied 40 patients with haemophilia A and B (24 with moderate–severe disease and 16 with mild disease), and 40 healthy controls. Flow‐mediated dilation (FMD), carotid ultrasound (US) intima media thickness (IMT), arterial blood pressure, body mass index (BMI), cholesterol, triglycerides, glucose, insulin, lipoprotein(a) and homocysteine levels were measured, and PAI‐1 and t‐PA levels before and after venous occlusion (VO), and antibodies to HIV, HBV and HCV were assayed. At least one cardiovascular risk factor was detected in 87.5% of patients, and 2 or more in 47.5% of cases. At US exam, none of the patients had significant carotid stenosis or significant differences in IMT compared to controls. In contrast, all the patients had a significant FMD impairment, associated with a reduced t‐PA release after VO in 70% of cases. PAI‐1 levels significantly correlated with BMI, triglycerides and insulin values. Fifteen haemophilia patients with chronic viral hepatitis and/or HIV infection showed a significantly lower FMD than patients without active infection. We found an endothelial dysfunction with impaired FMD and t‐PA release in our haemophilia patients, usually associated with cardiovascular risk factors. Other pathogenic mechanisms, such as chronic viral infections, are likely to be involved in this endothelial damage, however.

Contraceptive pills induce an improvement in congenital hypoplasminogenemia in two unrelated patients with ligneous conjunctivitis

Severe type I plasminogen deficiency is the underlying cause of ligneous conjunctivitis, a rare disease characterized by wood-like pseudomembranes developing on the ocular and extraocular mucosa. Two unrelated female patients with ligneous conjunctivitis and moderate hypoplasminogenemia are described. Being of fertile age, they were treated with oral contraceptives, which determined a marked increase in plasminogen levels. Moreover, a palpebral pseudomembrane stopped growing in one patient and disappeared completely in the other while on the estroprogestinic treatment. In patient n. 2, who also suffered from von Willebrands disease, prior Cushings disease induced an increase in both von Willebrand factor and plasminogen levels, which dropped after curative hypophysectomy. Genetic plasminogen study showed a 19Lys>Glu mutation in a heterozygous state in the first proposita and in a homozygous state in the second proband. In addition, both index patients were homozygous for a new intron F-14T>G mutation, which was found to reduce the acceptor splicing site prediction score. In conclusion, oral contraceptive therapy may improve plasminogen deficiency and deserves attention as an alternative therapeutic approach in selected cases of ligneous conjunctivitis with low, but not absent, plasminogen synthesis.

Circulating microparticles of glial origin and tissue factor bearing in high-grade glioma: a potential prothrombotic role

Venous thromboembolism (VTE) may complicate the clinical course of glioblastoma multiforme (GBM). Circulating microparticles (MPs) have been associated with cancer-related VTE. Sixty-one consecutive patients with GBM undergoing gross-total (41) or subtotal (20) surgical resection followed by radio-chemotherapy were prospectively evaluated. MPs numbers according to cellular origin and the procoagulant activity of annexin V positive (AV+) MPs (MP-activity) were measured before surgery and then 1 week and 1, 4, and 7 months after surgery. Glial (GFAP+) and endothelial (CD62E+) derived MPs, AV+ and tissue factor-bearing (TF+) MPs were measured using flow cytometry. Baseline levels of GFAP+/TF-, TF+/GFAP-, and GFAP+/TF+ MPs were significantly higher in GBM patients than in healthy controls, and significantly increased at each time point after surgery; at 7 months, a further significant increase over the level found a week after surgery was only seen in the subtotally resected patients. The number AV+/CD62E- MPs increased in GBM patients and correlated with MP activity. TF+/GFAP- MPs numbers were significantly higher in 11 GBM patients who developed VTE than in those who did not (p 0.04). TF+/GFAP- MPs levels above the 90th percentile (calculated in GBM patients without VTE) were associated with a higher risk of VTE (RR 4.17, 95% CI 1.57-11.03). In conclusion, the numbers of glial-derived and/or TF-bearing MPs were high in GBM patients both before and even more after the neoplasm was treated, especially in patients with subtotal resection likely according to disease progression. A contribution of TF+/GFAP- MPs to the risk of VTE is suggested.

Anti-prothrombin antibodies as a potential risk factor of recurrent venous thromboembolism.

The role of antiprothrombin (aPT) antibodies in the development of venous thromboembolism (VTE) is still uncertain. The aim of this study was to evaluate the potential role of aPT antibodies in the development of recurrent thromboembolism. Out of 236 consecutive symptomatic patients with an episode of acute VTE, antiphospholipid antibodies were found in 85 (36.0%), of whom 24 were carriers of aPT antibodies (10.2% of the entire cohort). A history of previous thromboembolism was identified in 56 patients (23.7%). The prevalence of previous thromboembolism was significantly higher in carriers than in non-carriers of antiphospholipid antibodies (OR=2.4; 95% CI, 1.3 to 4.4). Of the 24 patients with aPT antibodies, 12 had a history of previous thromboembolism. In a multivariate logistic regression analysis, in which the other categories of antiphospholipid antibodies were taken into account, as well as the patients age, sex, and the modality of clinical presentation, it was found that the presence of aPT antibodies was significantly associated with the prevalence of prior thromboembolism (OR=3.3; 95% CI, 1.3 to 8.6). Since aPT antibodies are more commonly identifiable in patients with multiple thrombotic episodes, they are a likely risk factor for recurrent thromboembolism.

Familial thrombophila associated with high levels of plasminogen activator inhibitor

A family with defective fibrinolytic abnormalities and recurrent thrombotic events is described. Impaired fibrinolysis was associated with high activity and concentration of fast-acting plasminogen activators inhibitor (PAI-1). Acquired conditions associated with PAI-1 increase were excluded. After venous occlusion testing, a different behaviour of fibrinolytic activity inhibition was seen in the family members. In the propositus and in two relatives only tissue (t-PA) plasminogen activity inhibition was found; in two other members, both t-PA and urokinase-type plasminogen activities were completely inhibited by the high PAI-1 levels. This fibrinolytic defect seems to be familial and transmitted as an autosomal trait.

Interaction between Histidine-Rich Glycoprotein and Platelet Factor 4 with Dermatan Sulfate and Low-Molecular-Weight Dermatan Sulfate

There is a controversy about whether or not histidine-rich glycoprotein (HRG), the most abundant plasma protein with glycosaminoglycans-neutralizing capacity, is able to prevent the inhibition of human thrombin by heparin cofactor II (HC II) in the presence of dermatan sulfate (DS). The authors studied the interaction of DS and low molecular weight DS, in a purified system with HRG, platelet factor 4 (PF 4), and with HC II. Their results show that HRG, like PF 4, has an affinity, not only for heparin, but also for DS. However, this affinity seems very weak. In fact, HRG is 10 times less effective than PF 4 in neutralizing the 50% antithrombin activity of HC II in the presence of DS.

Veno-occlusive disease in pediatric patients affected by Wilms tumor†

Hepatic veno‐occlusive disease (VOD) is a rare and potentially severe complication of chemotherapy. We describe five patients who developed VOD after chemotherapy for Wilms tumor (WT) and evaluate the role of plasminogen activator inhibitor‐1 (PAI‐1) and defibrotide for diagnosis and therapy of VOD, respectively.