Multiple von Willebrand factor mutations in patients with recessive type 1 von Willebrand disease.
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Adult↗
Biomedical subjects
Antonio Pagnan
Publications and source records attributed to Antonio Pagnan.
Identifying type Vicenza von Willebrand disease.
Increased clearance of von Willebrand factor (VWF) is one of the main features of type Vicenza von Willebrand disease (VWD), a variant with plasma and platelet VWF level discrepancies and unusually large VWF multimers. Diagnosing type Vicenza VWD may not be easy, due to its heterogeneous phenotype. Here we describe the criteria we adopted to identify type Vicenza in a large group of VWD patients. Emphasizing the contribution of platelet VWF by comparison with plasma values, a first step involved selecting the candidate Vicenza patients on the basis of low or very low plasma VWF and a normal platelet VWF content. After excluding type 2A and 2B VWD patients, who may have normal platelet VWF, 18 candidates were found to meet our selection criteria. Genetic analysis revealed that 15 patients (from 5 unrelated families) were type Vicenza VWD and that all carried both G2220A and G3614A type Vicenza mutations barring one, who only had the G3614A mutation. All patients had a reduced VWF survival, and all but the patient with the G3614A mutation alone had ultralarge VWF multimers. Thus, low-plasma VWF associated with a normal platelet VWF content may be a first useful indicator for identifying type Vicenza VWD patients.
Blood Platelets↗
Soluble endothelial protein C receptor (sEPCR) levels and venous thromboembolism in carriers of two dysfunctional protein C variants.
The role of the A3 haplotype and soluble endothelial protein C receptor (sEPCR) plasma levels in predisposing the carriers of two peculiar dysfunctional protein C (PC) variants (PC Arg-1-->Cys and PC Arg-1-->Leu, also known as PC Padua(2) and PC Padua(3), respectively) to venous thromboembolism (VTE) has been evaluated. The levels of sEPCR have been assessed in family members during 6 years of follow-up and correlated to the presence of the A3 haplotype. Individuals who carried both a dysfunctional PC and the A3 haplotype and presenting with high levels of sEPCR experienced severe VTE at young age. The increased plasma levels of sEPCR were not related to excessive thrombin generation. Carriers of the A3 haplotype showed levels of sEPCR above 135 ng/ml (80th percentile of the distribution in healthy subjects), which remained elevated during the follow-up. In non-carriers of the A3 haplotype, sEPCR levels remained persistently around 100 ng/ml or lower. In conclusion, we have observed that elevated sEPCR plasma levels and the concomitant presence of the A3 haplotype of EPCR gene are associated with severe thrombotic manifestations in carriers of two dysfunctional PC variants. Whether high plasma levels of sEPCR and/or the presence of the A3 haplotype increase the risk of thrombosis in carriers of other PC defects or thrombophilic conditions remains to be clarified.
Adult↗
Postthrombotic syndrome.
Despite considerable progress in the diagnosis and treatment of deep vein thrombosis (DVT) of the lower extremities, one of every three patients will develop postthrombotic sequelae within 2 years; these sequelae are severe in approximately 20% of cases and produce considerable socioeconomic consequences. Among factors potentially related to the development of the postthrombotic syndrome (PTS) are older age, obesity, insufficient oral anticoagulant therapy, and recurrent ipsilateral thrombosis. Whether the extent and location of the initial thrombosis are associated with the development of PTS is controversial. Based on recent findings, the lack of vein recanalization within the first 6 months appears to be an important predictor of PTS, whereas the development of transpopliteal venous reflux is not. The diagnosis of PTS can be made on clinical grounds for patients with a history of DVT. The combination of a standardized clinical evaluation with the results of compression ultrasonography and Doppler ultrasound helps diagnose or exclude a previous proximal vein thrombosis. According to the results of recent clinical studies, the prompt administration of adequate compression elastic stockings in patients with symptomatic DVT has the potential to reduce the frequency of late PTS development by half. The management of this condition is demanding and often frustrating. However, when carefully supervised and instructed to wear proper elastic stockings, more than 50% of patients will either remain stable or improve during long-term follow-up. Clinical presentation helps predict the prognosis; the outcome of patients who refer with initially severe manifestations is more favorable than that of patients whose symptoms deteriorate progressively over time.
Clinical Trials as Topic↗
The value of four-detector row spiral computed tomography for the diagnosis of pulmonary embolism.
Although spiral computed tomography (CT) is being used increasingly as the first-line imaging procedure in the diagnostic workup of patients with clinically suspected pulmonary embolism (PE), the diagnostic value of negative findings, at least when using the four-detector row scanners, is still controversial. A total of 702 consecutive patients with clinical symptoms suggestive of PE underwent four-slice CT. Patients with negative findings received the determination of D-dimer. Those with positive D-dimer underwent further diagnostic workup to confirm or rule out the diagnosis of PE. Those with negative D-dimer were followed-up to 6 months to detect the development of symptomatic venous thromboembolism (VTE). The CT test was interpreted as negative in 536 patients (76.3%). These patients had the D-dimer determination, which was positive in 279 and negative in the remaining 257 patients. Of the former, PE subsequently was documented in 55 patients (19.7%). Of the latter, symptomatic VTE in the follow-up period developed in three patients (1.17%; 95% confidence interval, 0.24 to 3.38%). In conclusion, when using the four-detector row, the negative predictive value of CT findings in patients with clinically suspected PE and positive D-dimer is low. In contrast, it is safe to withhold anticoagulation from patients with negative findings and negative D-dimer.
Adolescent↗
Cerebral venous thrombosis as a rare onset of Churg-Strauss syndrome.
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Adult↗
Does hemophilia protect against atherosclerosis? A case-control study.
Whether carriers of hemophilia are protected against the development of atherosclerosis is controversial. In a case-control study, the presence of atherosclerosis was assessed and quantified with echo-color Doppler of all explorable arterial districts in 50 carriers of hemophilia and in 50 age-matched control individuals. All participants submitted to echo-color Doppler of carotid and femoral axis, of brachial arteries, and of the abdominal aorta. The presence and grade of atherosclerotic plaques were assessed, as well as the intima-media thickness (IMT). At least one atherosclerotic plaque was found in six cases (12.0%) versus 15 controls (30.0%); referring to the total number of plaques, 30% of them were evaluated in patients affected by decreased coagulation while 70% in subjects with normal levels of FVIII. In all the examined districts, the mean IMT was significantly lower in patients with hemophilia than in controls. Hemophilia protects against asymptomatic atherosclerosis.
Adult↗
The risk of recurrent venous thromboembolism in patients with inherited deficiency of natural anticoagulants antithrombin, protein C and protein S.
Few data are available on the risk of recurrent venous thromboembolism (VTE) associated with the rare inherited deficiencies of natural anticoagulants. We studied 602 patients with previous VTE: the incidence of first recurrence in the absence of anticoagulation was retrospectively estimated in 64 patients with deficiency of antithrombin (AT, n=14), protein C (PC, n=28), or protein S (PS, n=22) and 538 with no known defect, who acted as the reference group. After adjustment for sex, age, and circumstances of the first event, AT deficiency resulted an independent risk factor for recurrence (hazard ratio 1.9, 95% CI 1.0-3.9); the carriers of PC or PS deficiency had a marginal increase in risk (hazard ratio 1.4, 95% CI 0.9-2.2). In conclusion, patients with AT deficiency are potential candidates for long-term oral anticoagulation.
3' Untranslated Regions↗
Combined partial exon skipping and cryptic splice site activation as a new molecular mechanism for recessive type 1 von Willebrand disease.
We describe the complex picture associated with a mutated splice junction in intron 13 of von Willebrand factor (VWF) gene. The proband, characterized by a marked decrease in plasma and platelet VWF and near normal multimer organization, was classified as recessive type 1 von Willebrand disease (VWD). Genetic analysis demonstrated that he was homozygous for the 1534-3C > A mutation in the consensus sequence of the acceptor splicing site of intron 13 of the VWF gene. Platelet mRNA analysis documented three VWF transcripts: a wild type generated by the correct recognition of the mutated splice site, a smaller transcript not containing exon 14, and a longer one that, in addition to exons 13 and 14, included a 62bp fragment corresponding to the end of intron 13. The small transcript derives from the skipping of exon 14, the long one from the activation of a cryptic splice site in intron 13; both show a premature stop codon in VWF propeptide, so the proband VWF derives entirely from the correct splice site recognition. Combined incomplete exon skipping and cryptic splice site activation are first recognized in VWD. Since the 1534-3C > A mutation does not abolish the normal processing of mRNA, it is unlikely to be found in type 3 VWD. This mutation therefore appears to be peculiar to type 1 VWD.
Adenine↗
Effects of long-term administration of high-dose recombinant human antithrombin in immunosuppressed primate recipients of porcine xenografts.
BACKGROUND: Fibrin deposition is central to the acute humoral rejection process occurring in the presence of consumptive coagulopathy when pig organs are transplanted into primates. METHODS: To assess whether strategies aimed at preventing fibrin formation may extend xenograft survival, we administered high daily doses of recombinant human antithrombin (rhAT) (500 U/kg twice daily) to obtain both anticoagulant and anti-inflammatory effects in immunosuppressed primate recipients of porcine kidneys. RESULTS: Some degree of consumptive coagulopathy developed in both rhAT-treated (n=3) and untreated (n=3) primates. No major differences in the coagulation parameters analyzed were observed between the 2 groups. Similarly, no difference in survival was seen between rhAT-treated (20.6+/-4 days; range: 15-23 days) and untreated animals (17.3+/-11.6 days; range: 7-30 days), although the rhAT-treated primates had a higher bleeding tendency. Despite the high daily dose of rhAT, considerable fibrin deposition was observed in the graft as early as 2 weeks after transplantation. CONCLUSIONS: These results suggest that a high daily dose of rhAT fails to influence survival or prevent fibrin formation and deposition in the graft in our pig-to-primate model. However, the potential role of rhAT administered in combination with heparins or other clotting inhibitor concentrates in this model remains to be determined.
Animals↗
Inactivation of vascular smooth muscle cells photosensitised by liposome-delivered Zn(II)-phthalocyanine.
Photodynamic therapy is a promising approach for the prevention of arterial restenosis, which frequently occurs after balloon angioplasty, largely owing to abnormal proliferation of vascular smooth muscle cells (VSMC) and their migration from the media to the intima, where they originate intimal hyperplasia (IH). We investigated the efficacy of Zn(II)-phthalocyanine-photosensitised processes in promoting the inactivation of VSMC. This liposome delivered phthalocyanine is readily taken up by VSMC, largely partitions in the Golgi apparatus, and upon photoactivation causes >95% cell mortality using mild irradiation conditions (e.g. 5 min irradiation at 1 microM ZnPc). Cell death occurs through the parallel development of random necrotic and apoptotic processes.
Animals↗
The effect of pre-eclampsia on the levels of coagulation and fibrinolysis factors in umbilical cord blood of newborns.
The effect of pre-eclampsia on coagulation and fibrinolysis in newborns is still under investigation. We have evaluated several coagulation and fibrinolysis parameters in umbilical cord blood of 20 newborns from pre-eclamptic women and of 40 newborns from normotensive women with similar gestational age. Additionally, the presence of factor V Leiden and prothrombin G20210A mutation in cord blood has been assessed. Neonates from pre-eclamptic women exhibited significantly lower birth weight (2.48 +/- 0.92 versus 2.88 +/- 0.68 kg, P < 0.05) and were more frequently admitted to the neonatal intensive care unit (45 versus 20%, P < 0.01) as compared with neonates from normotensive women. Cord blood protein C antigen and activated protein C resistance mean levels were slightly higher in the group of neonates from pre-eclamptic mothers. Fibrinogen levels were lower in this group as compared with control newborns (132.17 +/- 46.97 versus 156.08 +/- 49.58 mg%, P < 0.02), and unrelated to birth weight. No significant differences between cases and controls were found in plasminogen activator inhibitor-1 or tissue plasminogen activator cord blood levels. Heterozygous prothrombin 20210A was found in three newborns from normotensive mothers, whereas no factor V Leiden mutation was found in either group. In conclusion, pre-eclampsia seems to have only mild effects on coagulation and fibrinolytic factors in the cord blood of newborns. Since no excess of common polymorphisms predisposing to thrombosis was found in newborns from pre-eclamptic mothers, it is unlikely that the carriership status of these genetic defects of newborns influences the adverse pregnancy/neonatal outcomes.
Activated Protein C Resistance↗
Role of fibrinolytic and clotting parameters in the diagnosis of liver veno-occlusive disease after hematopoietic stem cell transplantation in a pediatric population.
Hepatic veno-occlusive disease (VOD) is a severe complication after hematopoietic stem cell transplantation (HSCT). Recent studies, mainly in adults receiving HSCT, have identified an increase in the plasminogen activator inhibitor-1 (PAI-1) as a possible marker of VOD. To confirm this finding, the fibrinolytic, coagulation and liver function parameters were assayed before and weekly for 1 month after 61 HSCT performed in 53 consecutive children. Non-VOD patients had a slight increase in t-PA antigen, fibrinogen and P-selectin levels, as well as a mildly longer aPTT and a drop in antithrombin after HSCT. The 6 children with VOD (9.84%) had an early and significant increase in PAI-1 antigen and activity (p<0.0001), t-PA antigen (p<0.0001) and D-dimer (p<0.01) levels, and a decrease in plasminogen, alpha 2-antiplasmin and PT emerged 2(+/-1) days before the clinical diagnosis of VOD by comparison with mean post-HSCT values in the non-VOD patients. Significant differences were also detected for these parameters and antithrombin levels between non-VOD and VOD patients soon after the clinical onset of VOD, whereas the rise in bilirubin levels became significant only later on. In conclusion, variations in fibrinolytic test findings after HSCT, and PAI-1 in particular, may facilitate the early diagnosis of VOD in pediatric patients after HSCT.
Adolescent↗
Below-knee elastic compression stockings to prevent the post-thrombotic syndrome: a randomized, controlled trial.
BACKGROUND: Because only limited evidence suggests that elastic stockings prevent the post-thrombotic syndrome in patients with symptomatic deep venous thrombosis (DVT), these stockings are not widely used. OBJECTIVE: To evaluate the efficacy of compression elastic stockings for prevention of the post-thrombotic syndrome in patients with proximal DVT. DESIGN: Randomized, controlled clinical trial. SETTING: University hospital. PATIENTS: 180 consecutive patients with a first episode of symptomatic proximal DVT who received conventional anticoagulant treatment. INTERVENTIONS: Before discharge, patients were randomly assigned to wear or not wear below-knee compression elastic stockings (30 to 40 mm Hg at the ankle) for 2 years. Follow-up was performed for up to 5 years. MEASUREMENTS: The presence and severity of the post-thrombotic syndrome were scored by using a standardized scale. RESULTS: Post-thrombotic sequelae developed in 44 of 90 controls (severe in 10) and in 23 of 90 patients wearing elastic stockings (severe in 3). All but 1 event developed in the first 2 years. The cumulative incidence of the post-thrombotic syndrome in the control group versus the elastic stockings group was 40.0% (95% CI, 29.9% to 50.1%) versus 21.1% (CI, 12.7% to 29.5%) after 6 months, 46.7% (CI, 36.4% to 57.0%) versus 22.2% (CI, 13.8% to 30.7%) after 1 year, and 49.1% (CI, 38.7% to 59.4%) versus 24.5% (CI, 15.6% to 33.4%) after 2 years. After adjustment for baseline characteristics, the hazard ratio for the post-thrombotic syndrome in the elastic stockings group compared with controls was 0.49 (CI, 0.29 to 0.84; P = 0.011). LIMITATIONS: This study lacked a double-blind design. CONCLUSIONS: Post-thrombotic sequelae develop in almost half of patients with proximal DVT. Below-knee compression elastic stockings reduce this rate by approximately 50%.
Adult↗
The long term clinical course of acute deep vein thrombosis of the arm: prospective cohort study.
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Adult↗
A new L1446P mutation is responsible for impaired von Willebrand factor synthesis, structure, and function.
We report on a new mutation (4337T-->C) in exon 28 of the von Willebrand factor (VWF) gene, resulting in a substitution of L with P at residue 1446 (L1446P) of pre-pro-VWF. The defect is transmitted as a dominant trait and induces a reduced VWF synthesis, an abnormal VWF multimer pattern and a deficient VWF-platelet glycoprotein Ib interaction. The proband had low plasma and platelet VWF antigen levels, a reduced VWF collagen-binding capacity, and a disproportionately low VWF ristocetin cofactor activity, associated with the absence of ristocetin-induced platelet aggregation. Multimer analysis showed that the smaller multimers were slightly low, whereas the larger ones were significantly reduced or absent, with a clear cutoff between the two patterns. Similar hemostatic findings were observed in the proband's sister and nephew. Desmopressin administration restored VWF levels to near normal, but this was not so for VWF ristocetin cofactor activity or ristocetin-induced platelet aggregation. VWF multimers improved after desmopressin, moreover, with the larger forms restored and the smaller ones still relatively more represented. Recombinant P1446 VWF synthesis was reduced at heterozygous level, and its multimer pattern was similar to that observed in plasma VWF. These findings confirm the role of L1446P mutation in determining the von Willebrand disease (VWD) phenotype observed in our patients. Given the lack of large and intermediate VWF multimers, and the fact that the VWF-platelet interaction defect appears to be partially independent of multimer pattern, the VWD associated with L1446P mutation may belong to the type 2A/2M VWD variant.
Adult↗
Whipple's disease.
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Endoscopy, Gastrointestinal↗
Alterations in the coagulation profile in renal pig-to-monkey xenotransplantation.
Five monkey recipients of a porcine renal xenograft were studied to determine the relationship between fibrin formation in acute humoral xenograft rejection (AHXR) and procoagulant and anticoagulant factor levels to establish whether changes in coagulation parameters could be used to predict AHXR and determine whether AHXR is associated with overt disseminated intravascular coagulopathy (DIC) in this model. Variable degrees of compensated consumptive coagulopathy were observed in each primate. Elevated thrombin-antithrombin (TAT), F1+2 and D-dimer levels consistent with thrombin generation and fibrin formation were recorded. There was no consumption of the main clotting inhibitors (including antithrombin) or a progressive, severe drop in fibrinogen levels and platelet counts, although grafts were left in situ. After transplantation, D-dimer levels remained persistently high, so they were of limited value in defining this coagulopathy. At post mortem, no cases of multiorgan involvement typical of overt DIC were observed. The lack of a rapid postoperative recovery of clotting inhibitor levels after transplantation was invariably associated with early poor outcome. This study shows that AHXR is associated with various degrees of compensated consumptive coagulopathy in our pig-to-primate model. No clear relationship was found between coagulation parameter levels and graft outcome.
Animals↗