One year of surgical mask testing at the University of Bologna labs: Lessons learned from data analysis

The outbreak of SARS-CoV-2 pandemic highlighted the worldwide lack of surgical masks and personal protective equipment, which represent the main defense available against respiratory diseases as COVID-19. At the time, masks shortage was dramatic in Italy, the first European country seriously hit by the pandemic: aiming to address the emergency and to support the Italian industrial reconversion to the production of surgical masks, a multidisciplinary team of the University of Bologna organized a laboratory to test surgical masks according to European regulations. The group, driven by the expertise of chemical engineers, microbiologists, and occupational physicians, set-up the test lines to perform all the functional tests required. The laboratory started its activity on late March 2020, and as of the end of December of the same year 435 surgical mask prototypes were tested, with only 42 masks compliant to the European standard. From the analysis of the materials used, as well as of the production methods, it was found that a compliant surgical mask is most likely composed of three layers, a central meltblown filtration layer and two external spunbond comfort layers. An increase in the material thickness (grammage), or in the number of layers, does not improve the filtration efficiency, but leads to poor breathability, indicating that filtration depends not only on pure size exclusion, but other mechanisms are taking place (driven by electrostatic charge). The study critically reviewed the European standard procedures, identifying the weak aspects; among the others, the control of aerosol droplet size during the bacterial filtration test results to be crucial, since it can change the classification of a mask when its performance lies near to the limiting values of 95 or 98%.

Procedure-dependence and Tissue Factor-independence of Hypercoagulability during Orthopaedic Surgery

The increased risk for deep vein thrombosis (DVT) after orthopaedic surgery has been well documented as well as hypercoagulable state during both total hip arthroplasty (THA) and total knee replacement (TKR). To investigate the influence of the surgical procedure [postero-lateral (PL) or lateral (L) approach for THA, use of tourniquet (TQ) or not use of TQ for TKR] on the hypercoagulability and the role of extrinsic pathway activation and endothelial stimulation during orthopaedic surgery we have examined 40 patients (20 patients undergoing primary THA – 10 with PL approach and 10 with L approach – and 20 patients undergoing TKR – 10 with TQ application and 10 without TQ). Thrombin-antithrombin complexes (TAT), tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombomodulin (TM) and von Willebrand factor antigen (vWF:Ag) were analyzed before and during the orthopaedic surgery. During THA, TAT plasma levels increased more markedly in patients assigned to the L than PL approach (p <0.05); during TKR an elevation of TAT of higher degree (p <0.05) was observed when TQ was not applicated. Blood clotting activation was significantly (p <0.001) more relevant during THA than TKR. No changes in TF and vWF:Ag plasma levels were observed in all patients undergoing THA and TKR. TFPI plasma levels significantly (p <0.05) decreased 1 h after the end of the THA in group PL and group L, whereas they remained unaffected in the two groups of patients undergoing TKR. Similarly TM plasma levels significantly decreased during THA, but not during TKR. In conclusion, these results show that: 1) the site of surgical procedures and the type of approach affect the degree of hypercoagulability, 2) the blood clotting activation takes place in the early phases of orthopaedic surgery, without signs of extrinsic pathway and endothelial activation.

Tissue Factor Reduction and Tissue Factor Pathway Inhibitor Release after Heparin Administration

Elevated plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) and large amounts of monocyte procoagulant activity (PCA) have been documented in unstable angina (UA) patients. In in vitro experiments heparin is able to blunt monocyte TF production by inhibiting TF and cytokine gene expression by stimulated cells and after in vivo administration it reduces adverse ischemic outcomes in UA patients. TF and TFPI plasma levels and monocyte PCA have been investigated in 28 refractory UA patients before and during anticoagulant subcutaneous heparin administration (thrice daily weight- and PTT-adjusted for 3 days) followed by 5000 IU × 3 for 5 days. After 2-day treatment, immediately prior to the heparin injection, TF and TFPI plasma levels [(median and range): 239 pg/ml, 130-385 pg/ ml and 120 ng/ml, 80-287 ng/ml] were lower in comparison to baseline samples (254.5 pg/ml, 134.6-380 pg/ml and 135.5 ng/ml, 74-306 ng/ml). Four h after the heparin injection TF furtherly decreased (176.5 pg/ml, 87.5-321 pg/ml; -32.5%, p<0.001) and TFPI increased (240.5 ng/ml, 140-450 ng/ml; +67%, p<0.0001).

After 7-day treatment, before the injection of heparin, TF and TFPI plasma levels (200 pg/ml, 128-325 pg/ml and 115 ng/ml, 70-252 ng/ml) significantly decreased (p<0.05) in comparison to the pre-treatment values. On the morning of the 8th day, 4 h after the injection of heparin TF plasma levels and monocytes PCA significantly decreased (156.5 pg/ml, 74-259 pg/ml and from 180 U/105 monocytes, 109-582 U/105 monocytes to 86.1 U/105 monocytes, 28-320 U/105 monocytes; - 38% and -55% respectively) and TFPI increased (235.6 ng/ml, 152-423 ng/ ml; +70%, p<0.001). In conclusion, heparin treatment is associated with a decrease of high TF plasma levels and monocyte procoagulant activity in UA patients. These actions of heparin may play a role in determining the antithrombotic and antiinflammatory properties of this drug.

Alterations of haemorheological parameters in patients with peripheral arterial disease

Peripheral arterial disease (PAD), is a common manifestation of systemic atherosclerosis. Advances on the development of such vascular disease have described with a number of novel risk factors. Hyperviscosity, due to alterations of blood cells and plasma components, may play a role on the pathogenesis of the disease. Aim of this study was to evaluate the possible association between hemorheological variables and PAD. The hemorheological variables [whole blood viscosity (WBV), erythrocyte deformability index (DI), plasma viscosity (PLV)] were analyzed in 90 patients and in 180 healthy subjects. WBV and PLV were measured by a Rotational Viscosimeter and DI by a filtrometer. DI and PLV were significantly different in patients as compared to controls. To investigate the possible association between these parameters and the disease we divided the study population into tertiles. At the univariate analysis, we found a significant association between the highest tertiles of PLV, of DI and the disease. A model adjusted for traditional risk factors showed an association between highest tertiles of PLV and PAD. After adjustment for confounding parameters highest tertiles of PLV remained to be significantly associated with the disease. Our data indicate that an alteration of plasma viscosity may modulate the predisposition to PAD.

A histidine-kinase cheA gene of Pseudomonas pseudoalcaligens KF707 not only has a key role in chemotaxis but also affects biofilm formation and cell metabolism

A histidine-kinase cheA gene in Pseudomonas pseudoalcaligenes KF707 plays a central role in the regulation of metabolic responses as well as in chemotaxis. Non-chemotactic mutants harboring insertions into the cheA gene were screened for their ability to form biofilms in the Calgary biofilm device. Notably, ≥95% decrease in the number of cells attached to the polystyrene surface was observed in cheA mutants compared to the KF707 wild-type biofilm phenotype. The ability to form mature biofilms was restored to wild-type levels, providing functional copies of the KF707 cheA gene to the mutants. In addition, phenotype micro-arrays and proteomic analyses revealed that several basic metabolic activities and a few periplasmic binding proteins of cheA mutant cells differed compared to those of wild-type cells. These results are interpreted as evidence of a strong integration between chemotactic and metabolic pathways in the process of biofilm development by P. pseudoalcaligenes KF707.

Protein Z-dependent protease inhibitor and protein Z in peripheral arterial disease patients

SUMMARY INTRODUCTION

Protein Z is a vitamin K-dependent protein that serves as a cofactor for the inhibition of activated factor X by the serpin protein Z-dependent protease inhibitor (ZPI). Protein Z plasma levels have been shown to be reduced in patients with peripheral arterial disease (PAD), but ZPI levels have not yet been reported. The aim of this study was to more fully assess the protein Z-ZPI system in individuals with atherosclerosis selected by the presence of symptomatic PAD.

MATERIALS AND METHODS

Protein Z and ZPI levels were determined in 95 PAD patients (73 males; 22 females) [median age: 73 years (range, 50-86 years)] and in 190 controls comparable for age and gender. Protein Z was measured using a commercial immunoassay, and ZPI was measured with a homemade immunoassay and a functional assay.

RESULTS

Protein Z antigen, ZPI antigen and ZPI function were found to be significantly lower in PAD patients with respect to controls [protein Z, median 72.5% (range: 3.4-123.7%) vs. 90.7% (range: 32.1-203.2%), P < 0.0001; ZPI antigen, 86.1% (range: 25.1-149.5%) vs. 93.2% (range: 48.9-171.3%), P = 0.004; ZPI function, 83.5% (range: 21.1-135.2%) vs. 97.2% (range: 50.5-175.5%), P < 0.0001]. The lowest tertiles of protein Z antigen [odds ratio (OR) 5.4, 95% confidence interval (CI) 2.2-13.5, P < 0.0001] and ZPI function (OR 2.4, 95% CI 1.1-5.5, P = 0.03) were associated with PAD on multivariate analysis after adjustment for age, gender, and traditional cardiovascular risk factors. A significant inverse relationship was also observed between protein Z and ZPI levels and the number of traditional cardiovascular risk factors and the clinical severity of disease (Fontaine stage).

CONCLUSIONS

Low levels of protein Z antigen and protein Z activity are significantly associated with the occurrence and severity of atherosclerotic PAD.

Leisure time but not occupational physical activity significantly affects cardiovascular risk factors in an adult population

BACKGROUND

A large number of studies have demonstrated that regular physical activity during leisure time (LTPA) accounts for a significant protection against cardiovascular diseases (CVD). On the other hand, conflicting findings on the beneficial effects of occupational physical activity (OPA) have been reported. The aim of this study is to evaluate the possible influence of different amounts of LTPA and OPA on circulating levels of several parameters associated with an increased risk of CVD.

MATERIALS AND METHODS

We studied 932 individuals (365 M; 567 F, with a mean age of 54 years) living in Florence, Italy, who were enrolled in a population study conducted between 2002 and 2004. Subjects were divided into three classes of LTPA and OPA according to a score derived from a questionnaire that assessed the amount of physical activity performed.

RESULTS

LTPA was inversely related to body mass index (BMI), hip circumference, diastolic blood pressure and triglycerides, as well as directly correlated with high-density lipoprotein (HDL) cholesterol. Likewise, a higher OPA was found to be associated with higher HDL cholesterol levels. Moreover, a multivariate logistical regression analysis, adjusted for possible confounders, showed that a moderate-to-high intensity of LTPA was able to confer a significant protection against having abnormal levels of BMI, waist circumference and triglycerides, main features of the metabolic syndrome, whereas no associations between these parameters and OPA were observed.

CONCLUSIONS

A moderate-to-high LTPA was found to be significantly associated with a more favourable cardiovascular risk profile in terms of anthropometric, metabolic and lipid parameters among an Italian population. In addition, a relationship between OPA and HDL-cholesterol was reported.

Protein Z plasma levels in different phases of activity of coronary atherosclerosis

We previously reported that low protein Z plasma levels are associated with acute coronary syndromes (ACS). Aim of the present study was to evaluate protein Z levels in different phases of activity of coronary atherosclerosis. Protein Z plasma levels were measured in 166 (131 male and 35 female) patients consecutively admitted to the University of Florence with a diagnosis of ACS (group A), 166 (131 male and 35 female) patients selected by age and gender in relation to group A from those with a clinical history of ACS who remained symptom- and/or event-free over the last year before the investigation (group B); and 332 (262 male and 70 female) controls comparable for age and gender with the other two groups. None had liver or renal dysfunction nor showed a positivity for antiphospholipid antibodies or for factor V Leiden mutation. Patients under warfarin therapy were excluded. Mean protein Z plasma levels were found to be significantly (P < 0.0001) lower in group A (1475 +/- 684.1 ng mL(-1)) and group B (1327.6 +/- 690.7 ng mL(-1)) as compared with control group (1650.1 +/- 634.5 ng mL(-1)), while no significant differences existed between the two groups of patients (P = 0.06). A logistic regression analysis, performed after the division of the study population into quartiles of protein Z levels and adjusted for all possible confounders, showed a significant increased risk of ACS for the lowest (<1213 ng mL(-1)) as compared with the highest quartile of protein Z in both groups of patients [group A odds ratio (OR): 2.7, 95% CI 1.3-5.5, P = 0.007; group B OR: 3.2, 95% CI 1.1-8.9, P = 0.02). In conclusion, these results strengthen our previous data on low protein Z plasma levels in ACS and indicate a possible dose-response effect of decreasing protein Z plasma levels on the coronary atherosclerotic disease.

Dietary habits, lifestyle and cardiovascular risk factors in a clinically healthy Italian population: the 'Florence' diet is not Mediterranean

OBJECTIVE

To evaluate dietary habits and lifestyle of Italian subjects, to provide current data on adequacy of the nutritional guidelines and recommendations especially in relation to primary prevention of cardiovascular diseases and to assess the influence of dietary habits on lipid profile and homocysteine levels.

DESIGN

Cross-sectional.

SETTING

Population-based study.

SUBJECTS

A sample of 520 clinically healthy subjects (211 males, 309 females) with a mean age of 46 y, living in Florence area, Italy.

INTERVENTIONS

Dietary pattern was assessed by trained dietitians through a semiquantitative food questionnaire. Fasting blood samples were drawn for assessment of lipid profile, homocysteine and circulating vitamins.

RESULTS

Contribution from total fats was over 30% in about 70% of subjects and intake of saturated fatty acids (SFA) was above the recommended values in at least 40% of the study population. Furthermore, almost the whole (99.6%) population reported low intake of polyunsaturated fatty acids (PUFA). High levels of total cholesterol were present in over 40% of the study population, whereas abnormal values of LDL-cholesterol were observed in about 30%. High levels of homocysteine were found in 11.7% of the study population. An extremely high percentage of subjects reported low intake of vitamins, especially with regard to folic acid (89%), vitamin B(6) (70.1%) and vitamin E (99.6%). In a multiple linear regression model, circulating levels of vitamin B(12) and folic acid, and intake of alcohol and vitamin C resulted in being independently associated with homocysteine plasma levels.

CONCLUSIONS

In a typical Mediterranean country, general outlines of Mediterranean diet are not completely followed, especially concerning total fats, SFA, PUFA and vitamins' intake.

SPONSORSHIP

Ministero della Salute (Italy) - 'Progetto per la Salute e la Prevenzione di Malattia' 2001-2003.

Homocysteine-Lowering Therapy and Carotid Intima-Media Thickness in Renal Transplant Recipients

The aim of this study was to document, in hyperhomocysteinemic renal transplant recipients, the effect of vitamin supplementation on carotid intima-media thickness (cIMT). Fifty-six hyperhomocysteinemic stable renal transplant recipients were randomly assigned to either vitamin supplementation (group A) or placebo treatment (group B). All patients underwent high-resolution B mode ultrasound to measure IMT of common carotid arteries before and after 6 months of vitamin supplementation. In group A, cIMT significantly decreased after treatment, whereas no significant changes were observed in group B. In conclusion, our results demonstrate a beneficial effect of the treatment of hyperhomocysteinemia by vitamin supplementation on an early sign of atherosclerosis in a group of renal transplant recipients.

Thrombophilic risk factors in patients with severe carotid atherosclerosis

Carotid stenosis and atrial fibrillation are the strongest risk factors for ischemic stroke. Ongoing prevention efforts include the identification of novel factors that increase the risk for carotid atherosclerosis. The aim of this study was to determine the thrombophilic risk profile of patients with severe carotid stenosis by evaluating a number of genetic and metabolic risk factors [factor (F)II G20210A, factor V Leiden, MTHFR C677T polymorphisms, anticardiolipin antibodies (aCL), lipoprotein(a) (Lp(a)), and homocysteine (Hcy)]. The study population consisted of 615 patients [(410 M/205 F; median age 73 (26-94) years] with severe (> 70%) carotid stenosis, and 615 apparently healthy subjects [(410 M/205 F; age 73 (31-92) years]. On multivariate analysis, independent risk factors were elevated Hcy [odds ratio (OR) 7.6, 95% confidence interval (CI) 4.8, 11.8] and Lp(a) levels (OR 2.9, 95% CI 2.1, 3.9), the presence of aCL (OR 5.7, 95% CI 3.1, 10.4) and heterozygosity for FII G20210A polymorphism (OR 2.8, 95% CI 1.3, 5.9). In the subgroup of women, independent risk factors for severe carotid atherosclerosis were: high levels of Hcy and Lp(a) and the presence of aCL, whereas hyperhomocysteinemia, elevated Lp(a) levels, aCL, FII G20210A and MTHFR 677TT polymorphisms remained independent risk factors in the subgroup of men. The results of the present study demonstrate that the prevalence of the thrombophilic risk factors is increased in patients with severe carotid atherosclerosis.

Relevance of post-methionine homocysteine and lipoprotein (a) in evaluating the cardiovascular risk in young CAD patients

BACKGROUND

Aims of our study were to evaluate the prevalence of high lipoprotein (a) [Lp(a)] and homocysteine levels - both in the fasting state (FHcy) and post-methionine (PMHcy) - in young coronary artery disease (CAD) patients, and to investigate the role of genetic and environmental factors for hyperhomocysteinaemia.

MATERIALS AND METHODS

We studied 140 patients with angiographically documented CAD (24 women </= 55 years and 116 men </= 50 years) and 140 healthy subjects as controls.

RESULTS

Both FHcy [13.2 (5.4-45.8) vs. 9.0 (5.1-24) micromol L(-1)); P < 0.0001] and PMHcy [(39.4 (9.0-66.4) vs. 25.2 (16.4-33.9); P < 0.0001] were significantly higher in patients than in controls. Lp(a) levels were significantly higher in patients than in controls (200 (3-1486) mg L(-1) vs. 97 (10-412) mg L(-1); P < 0.0001). At the multivariate analysis, adjusted for the classical cardiovascular risk factors and creatinine levels, the OR (95% CI) for CAD at young age significantly increased in the fourth quartile of the distribution of FHcy, PMHcy and Lp(a) levels [FHcy: 14.9 (4.1-58), P < 0.0001; PMHcy: 19.2 (4.0-86.3); P < 0.0001; Lp(a): 19.6 (4.7-78.6): < 0.0001]. Vitamin deficiencies were detected in 28/140 (20%) patients. The prevalence of the homozygous C677T (+/+) methylenetetrahydrofolatereductase genotype was higher, but not significantly different, in patients (22.8%) than in controls (18.6%). The allele frequency of the 844ins68 insertion variant in the cystathionine beta-synthase gene was 0.08 in the control group and 0.06 in the patient group.

CONCLUSIONS

Results of the present study indicate the usefulness of including fasting and post-methionine Hcy, and Lp(a) determination in the diagnostic panels of young CAD patients, in order to obtain a better assessment of their cardiovascular risk profile.

Thrombophilias as risk factors for disorders of pregnancy and fetal damage

Inherited thrombophilias have been suggested as a possible condition of increased susceptibility to adverse pregnancy outcomes. Although there is no consensus on the association between the factor V Leiden mutation and early (less than 10 weeks) pregnancy loss, the evidence suggests an association between the mutation and second-, and third-trimester fetal loss and severe preeclampsia. At present the relationship between the prothrombin G20210A mutation and inherited thrombophilias and adverse pregnancy outcomes remains controversial. Due to the low prevalence, AT and PC deficiencies have been rarely found as the cause of complicated pregnancy, whereas increased risk for preeclampsia and fetal losses has been found in relation to PS deficiency. Concerning the association between pathological pregnancies and PAI-1 4G/5G deletion/insertion polymorphism, only few controversial data are available. A meta-analysis of ten case-control studies suggested an association between hyperhomocysteinemia, MTHFR C677T mutation and repeated pregnancy losses before 16 weeks. Recently a role for Angiotensin Converting Enzyme I/D polymorphism in obstetrical complications has been suggested.

ACE DD genotype: an independent predisposition factor to venous thromboembolism

BACKGROUND

The renin angiotensin system affects haemostasis through different mechanisms; data on the possible role of angiotensin-converting enzyme I/D polymorphism in the pathogenesis of deep venous thrombosis are conflicting, and no information is available regarding the A1166C polymorphism of the angiotensin type 1 receptor gene. In order to investigate this issue, angiotensin-converting enzyme and AT1R polymorphisms were genotyped in 336 consecutive venous thromboembolism patients and 378 controls.

MATERIALS AND METHODS

Haemostasis-related risk factors have been evaluated by routine tests. Factor V Leiden, Factor II (G20210A), angiotensin-converting enzyme (I/D), and angiotensin type 1 receptor (A1166C) polymorphisms have been identified by molecular analysis.

RESULTS

We documented a significant association between angiotensin-converting enzyme DD genotype and venous thromboembolism (OR=2.19 95%CI 1.51-3.17 adjusted for acquired and haemostasis-related risk factors, P<0.0001); in patients with haemostasis-related risk factors, angiotensin-converting enzyme DD genotype modified the risk of venous thromboembolism in hyperhomocysteinaemic and Factor V Leiden patients and was associated with the risk of recurrent venous thromboembolism (OR=1.83 95%CI 1.06-3.17 P=0.03). In patients without haemostasis-related risk factors the angiotensin-converting enzyme DD genotype was still an independent predictor of venous thromboembolism (OR=3.29 95%CI 2.17-4.98 adjusted for acquired risk factors, P<0.0001). No significant association between the angiotensin type 1 receptor CC genotype and venous thromboembolism was found.

CONCLUSIONS

This study shows that angiotensin-converting enzyme DD genotype represents a susceptibility marker of thrombosis in subjects apparently without predisposing factors and traditional thrombophilic alterations, and increases the risk of venous thromboembolism in subjects in whom a thrombogenic condition occurs. Moreover, angiotensin-converting enzyme DD genotype may be considered a new predisposing factor to venous thromboembolism recurrence.

Reduction of potassium tellurite to elemental tellurium and its effect on the plasma membrane redox components of the facultative phototroph Rhodobacter capsulatus

Anaerobically light-grown cells of Rhodobacter capsulatus B100 are highly resistant to the toxic oxyanion tellurite (TeO(3)(2-); minimal inhibitory concentration, 250 microg/ml). This study examines, for the first time, some structural and biochemical features of cells and plasma membrane fragments of this facultative phototroph grown in the presence of 50 microg of K(2)TeO(3) per ml. Through the use of transmission microscopy and X-ray microanalysis we show that several "needlelike" shaped granules of elemental tellurium are accumulated into the cytosol near the intracytoplasmic membrane system. Flash-spectroscopy, oxygen consumption measurements, and difference spectra analysis indicated that membrane vesicles (chromatophores) isolated from tellurite-grown cells are able to catalyze both photosynthetic and respiratory electron transport activities, although they are characterized by a low c-type cytochrome content (mostly soluble cytochrome c(2)). This feature is paralleled by a low cytochrome c oxidase activity and with an NADH-dependent respiration which is catalyzed by a pathway leading to a quinol oxidase (Qox) inhibited by high (millimolar) concentrations of cyanide (CN(-)). Conversely, membranes from R. capsulatus B100 cells grown in the absence of tellurite are characterized by a branched respiratory chain in which the cytochrome c oxidase pathway (blocked by CN(-) in the micromolar range) accounts for 35-40% of the total NADH-dependent oxygen consumption, while the remaining activity is catalyzed by the quinol oxidase pathway. These data have been interpreted to show that tellurite resistance of R. capsulatus B100 is characterized by the presence of a modified plasma-membrane-associated electron transport system.

Tissue factor and tissue factor pathway inhibitor levels in unstable angina patients during short-term low-molecular-weight heparin administration

High tissue factor (TF), tissue factor pathway inhibitor (TFPI) levels and a hypercoagulability state have been documented in unstable angina patients. We evaluated whether short-term enoxaparin administration (100 IU/kg b.i.d. for 3 d) reduces the high TF levels and the hypercoagulability state, and whether it influences the fibrinolytic system in 20 unstable angina patients. On d 3, we observed a significant reduction in TF levels both 1 h and 4 h after the morning injection (-25.6% and -21.7%; P < 0.001 respectively) in comparison with the base-line levels. Both 1 and 4 h after the morning injection on the d 3, TFPI levels significantly (P < 0.001) increased (+96.4%, +96.9% respectively) with respect to the base-line values. After enoxaparin administration, at all observation times, thrombin-antithrombin complexes and prothrombin fragment F1 + 2 levels were significantly (P < 0.001) lower with respect to base-line levels. We observed a slight but significant increase in tissue plasminogen activator antigen levels in preinjection samples, as well as 1 h and 4 h after enoxaparin administration, in comparison with the base-line values. This study provides evidence that low-molecular-weight heparin (LMWH) administration, in addition to a reduction of hypercoagulability and a mild fibrinolytic activation, is associated with decreased TF levels, so indicating a novel mechanism of interference of LMWH with the haemostatic system.

Comparison of three methods for total homocysteine plasma determination

Hyperhomocysteinemia is a well established risk factor for atherothrombotic disease, and the request for homocysteine determinations and the number of laboratories that need to perform this assay to assess individual risk profile is increasing. Different methods to evaluate homocysteine plasma levels are at present available. In the present study three methods, an in-house high-pressure liquid chromatographic (HPLC) method (considered as reference method) and two commercial immunoassays, an enzyme-linked immunoassay (EIA) and an automated fluorescence polarization immunoassay (FPIA), were used to measure homocysteine plasma levels in 100 samples. The median of homocysteine plasma levels obtained by HPLC was 9.0 micromol/L (range 4.2-23.0); the median of values obtained by EIA and FPIA were 10.6 micromol/L (range 3.3-21.5) and 9.6 micromol/L (4.8-20.2), respectively. The FPIA method showed the lowest within-run and between-run coefficients of variation (3.6% and 4.1%, respectively). There was a significant correlation between EIA and HPLC (r=0.81; p<0.0001), and between FPIA and HPLC (r=0.85; p<0.0001). The Bland-Altman analysis showed that FPIA agreed best with HPLC; EIA displayed a relatively wide scatter of difference data points. The present results indicate that the technological characteristics of the FPIA assay make this method suitable for the determination of Hcy in clinical laboratories.

D-dimer increase after percutaneous transluminal angioplasty and clinical recurrence after primary revascularization in acute myocardial infarction? A pilot study

It has been reported that the increase of plasminogen activator inhibitor-1 activity immediately after elective coronary angioplasty is related to subsequent clinical recurrence in patients with chronic coronary artery disease. The aims of our study were to evaluate the behavior of plasminogen activator inhibitor-1 and D-Dimer after revascularization in acute myocardial infarction patients treated with angioplasty and stenting and if this behavior is predictive of subsequent clinical recurrence. D-Dimer and plasminogen activator inhibitor-1 activity were evaluated in two groups of patients. Group 1 consisted of 54 consecutive patients undergoing primary angioplasty for acute myocardial infarction and Group 2 consisted of 48 patients undergoing elective angioplasty. Patients underwent control coronary angiography only in the case of clinical recurrence and/or positivity of provocative tests. D-Dimer and plasminogen activator inhibitor-1 baseline levels were significantly higher in group 1 than in group 2 (P<0.0005 and P<0.05, respectively). The percentage of group 1 patients with a post-procedural increase in D-Dimer was significantly higher among those with subsequent clinical recurrence with restenosis (61%) than among those with no recurrence (25%, P<0.05). No difference was observed in group 2. The percentage of group 2 patients in whom no decrease of plasminogen activator inhibitor-1 was observed after angioplasty was significantly higher (83%) among those with subsequent recurrence than among those with no recurrence (38%, P<0.05). This pattern was not observed in group 1. In conclusion, the role of early changes in plasminogen activator inhibitor-1 in predicting clinical recurrence after primary angioplasty in acute myocardial infarction patients is less clear than that observed after elective angioplasty. A significant role seems to be played by a more-marked clotting activation with increased fibrin formation.

Postprocedural PAI-1 activity is a risk marker of subsequent clinical restenosis in patients both with and without stent implantation after elective balloon PTCA

Stent implantation after balloon dilation of coronary arteries has improved clinical prognosis in patients undergoing transluminal coronary angioplasty (PTCA), but late restenosis remains a relevant problem. A previous study has indicated that PAI-1 activity changes immediately after PTCA without stent implantation are predictive of clinical restenosis. The present study was aimed to investigate the early PAI-1 changes and fibrin formation in patients undergoing elective PTCA with stent implantation. PAI-1 activity and D-dimer plasma levels were evaluated in two groups of patients (G1 underwent only elective balloon PTCA and G2 underwent elective PTCA with stent implantation) before and after the procedure. At the end of the procedure, PAI-1 activity significantly decreased, while D-dimer levels significantly increased in both groups. Post-PTCA D-dimer levels in the group with stent implantation were significantly higher than in the other group (P<.05). In both groups of patients, the post-PTCA PAI-1 activity was higher in patients with subsequent clinical recurrence with restenosis (P<.005 in G1 and P<.0005 in G2) than in those without, whereas no differences were found in D-dimer levels. In conclusion, our results demonstrate that fibrin formation assessed by D-dimer levels is enhanced by stent implantation. However, this behaviour is not related, differently from PAI-1 changes, to subsequent occurrence of clinical restenosis.

Thrombophilic risk factors in patients with central retinal vein occlusion

Few and contrasting data are available on the prevalence of hemostatic risk factors in patients with central retinal vein occlusion (CRVO). Aim of this study was to investigate the metabolic and inherited risk factors for venous thrombosis in 100 CRVO patients (age: 59 yrs; range 18-77) and in 100 controls (age: 56 yrs; range 18-84). In patients homocysteine (Hcy) levels were significantly higher than in controls and were affected by the C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism (p < 0.001). The prevalences of activated protein C resistance (APCR), factor V Leiden positivity, elevated PAI-1 and Lp(a) levels were significantly higher in patients with respect to controls. At multivariate analysis, only hyperhomocysteinemia (OR 11, 95% CI 3.6-36.2; p < 0.0001) and elevated PAI-1 levels (OR 8.9, 95% CI 3.5-41.3; p < 0.01), in addition to hypertension (OR 40.5, 95% CI 8.6-188.8; p < 0.00001) and hypercholesterolemia (OR 3.1, 95% CI 1.6-20.5; p < 0.05), were independent risk factors for CRVO. These data demonstrate a potential role of hemostatic risk factors in the pathophysiology of CRVO.

Angiotensin converting enzyme DD genotype affects the changes of plasma plasminogen activator inhibitor-1 activity after primary percutaneous transluminal coronary angioplasty in acute myocardial infarction patients

Angiotensin converting enzyme (ACE) DD genotype, and plasminogen activator inhibitor (PAI-1) 4G/4G genotype have been reported to affect PAI-1 activity in control subjects and atherosclerotic patients, but no data are available on the influence of angiotensin II type 1 receptor (AT1R) A1166C polymorphism on the inhibitor levels. The degree of fibrinolytic activation after percutaneous transluminal coronary angioplasty (PTCA) has been found to affect the risk of restenosis. The aim of this study was to investigate the possible influence of ACE I/D, AT1R A1166C, and PAI-1 4G/5G polymorphisms on the changes of PAI-1 activity after primary successful percutaneous transluminal angioplasty. In 29 consecutive acute myocardial infarction patients, undergoing primary successful angioplasty, genotyping of ACE I/D, AT1R A1166C, and PAI-1 4G/5G polymorphisms was performed by polymerase chain reaction and restriction fragment length polymorphism analysis, and PAI-1 plasma activity (chromogenic method) was assessed before and after angioplasty. Following angioplasty, PAI-1 activity increased in 10 of 29 patients and decreased or remained unchanged in 19 of 29. ACE DD genotype was significantly (P = 0.04) associated with an increase of PAI-1 activity post angioplasty (OR DD/ID+II = 6.5, CI 95% 4.83-8.22). Whereas no effect of PAI-1 4G/5G and AT1R A1166C polymorphisms on PAI-1 response to angioplasty was demonstrated, these data suggest that renin-angiotensin system genes are involved in the regulation of the fibrinolytic response to balloon injury, possibly affecting angiotensin converting enzyme activity. This interaction between the renin-angiotensin system and hemostasis may be a mechanism by which ACE DD genotype affects the risk of restenosis after percutaneous transluminal angioplasty.

Polychlorinated biphenyl degradation activities and hybridization analyses of fifteen aerobic strains isolated from a PCB-contaminated site

Fifteen bacterial strains using biphenyl as sole carbon and energy source, obtained from different positions and depths of a polychlorinated biphenyl (PCB)-contaminated area, were analyzed for their basic metabolic phenotypes and subjected to genomic DNA hybridization screening for the presence of well characterized bph operons such as those of Pseudomonas pseudoalcaligenes KF707 and Rhodococcus globerulus P6. Most of the isolates belonged to the gamma-subdivision (Pseudomonas stutzeri, P. plutida, P. fluorescens and Vibrio logei species) and to the beta-subdivision (genera Alcaligenes, Comamonas, Ralstonia) of the Proteobacteria. All the isolates were able to cometabolize different low chlorinated PCB congeners. Among the dichlorinated biphenyls tested, a lower degradation capacity was observed for the di-ortho substituted congeners, whereas high levels of degradation were observed for the di-meta and di-para isomers, whether they were chlorinated on one or on both rings. The PCB congeners nonsubstituted in the 2,3 or 2,3 and 3,4 positions were also degraded by most of the isolated strains, which were, however, unable to significantly metabolize PCBs with more than 3 chlorine atoms. Five of the isolated strains were also able to degrade some of the tri- and tetrachlorobiphenyls tested. Southern hybridization analysis showed a strong homology between four of the fifteen isolated strains and the bph operon obtained from P. pseudoalcaligenes strain KF707. Conversely, none of the isolates here examined showed homology with the bph operon of R. globerulus strain P6. In line with this, the KF707 bph probe strongly hybridized with DNA of a significant number of bacterial colonies obtained from selected locations in the contaminated area using biphenyl-supplemented minimal medium agar plates.

The role of cysteine and homocysteine in venous and arterial thrombotic disease

Hyperhomocysteinemia is a risk factor for arterial and venous thrombosis, whereas few data are available on the total cysteine (tCy) levels in thrombophilic patients. We studied 82 patients with a previous myocardial infarction (MI; group 1), 68 patients with a previous deep venous thrombosis (group 2), and 100 control subjects (group 3). We assayed total homocysteine (tHcy) and tCy levels by high-performance liquid chromatography with fluorimetric detection. The odds ratios (ORs) for high levels of tCy and tHcy in venous thrombosis and MI were markedly increased in group 1 (fasting tCy: OR, 3.6; 95% confidence interval [CI], 1.6-11.2; postmethionine tCy: OR, 0.97; CI, 0.3-4.0; fasting tHcy: OR, 8.3; CI, 3.9-18.6; postmethionine tHcy: OR, 12.5; CI, 6.8-27.2) and in group 2 (fasting tCy: OR, 2.9; CI, 1.1-7.8; postmethionine tCy: OR, 0.86; CI 0.2-2.6; fasting tHcy: OR, 8.0; CI 3.6-18.0; postmethionine tHcy: OR, 11.0; CI, 6.0-22.1). Our data suggest that plasma tCy levels are a risk factor for venous thrombosis and MI independently of tHcy levels and that it may be appropriate to study both variables simultaneously to thoroughly study the methionine metabolism.

Risk factors for cardiovascular disease in renal transplant recipients: new insights

Long-term survival of renal transplant recipients appears to be influenced by the occurrence of thromboembolic complications and cardiovascular disease. In order to investigate the prevalence of new hemostasis-related risk factors for venous and arterial thrombosis, we investigated 63 renal transplant recipients and 66 age- and sex-matched control subjects. We assayed antiphospholipid antibodies [lupus anticoagulant (LA) and anticardiolipin antibodies (aCL)], lipoprotein (a) [Lp(a)], plasminogen activator inhibitor-1 (PAI-1), and total homocysteine (tHcy) levels. We found a significantly higher prevalence of positivity for LA (P < 0.001); no difference was detected in the prevalence of aCL between patients and controls. PAI-1 levels were significantly higher in renal transplant recipients than in controls [12.3 IU/ml (2-45.5) vs 7.9 IU/ml (4-18.0); P < 0.0001] with an odd ratio (OR) of 11.8 (4.9-28.5) in univariate analysis and of 5.8 (2.1-15.4) in multivariate analysis. Lp(a) levels were higher in patients then in controls [159 mg/l (1-992) vs 100.5 mg/l (10-412); P < 0.005] with an OR of 5.9 (1.9-18.4) in univariate analysis and of 3.5 (0.9-13.4) in multivariate analysis. Fasting levels of tHcy were significantly higher in renal transplant recipients [7.0 micromol/l (4.0-68) vs 8.1 micromol/l (2.0-24.0); P < 0.00001] with an OR of 40.4 (14.7-111) in univariate analysis and of 33.1 (11.1-115.5) in multivariate analysis. After methionine loading test, we documented levels of tHcy above the 90th percentile of controls in 60/63 patients (95%). Finally, we found a significant correlation between tHcy and PAI-1 plasma levels (r = 0.76; P < 0.000001). Our results show a high prevalence of hemostasis-related risk factors for arterial and venous thrombosis in renal transplant recipients, suggesting the need for the investigation of these patients for the presence of these risk factors in order to improve their long-term survival and to tailor therapy.

High cysteine levels in renal transplant recipients: relationship with hyperhomocysteinemia and 5,10-MTHFR polymorphism

BACKGROUND

Long-term survival of renal transplant recipients seems to be influenced by the occurrence of thromboembolic complications and cardiovascular disease. Preliminary data available in the literature found high levels of cysteine (Cy) as a risk factor for deep venous thrombosis independently of high homocysteine (tHcy) levels, but no data are available about Cy levels in renal transplant recipients.

METHODS

To investigate Cy, tHcy, and plasminogen activator inhibitor-1 (PAI-1) levels and the prevalence of 5,10-methylenetetrahydrofolate reductase (MTHFR) in renal transplantation, we studied 70 stable renal transplant recipients and 66 age- and sex-matched normal subjects as controls.

RESULTS

Cy, tHcy, and PAI-1 levels were significantly higher in renal transplant recipients with respect to controls (Cy: 254 micromol/L [117-466] vs. 198 micromol/L [99-331], P<0.001; tHcy: 17.0 micromol/L [4.0-68] vs. 8.1 micromol/L [2.0-24.0], P<0.00001; PAI-1: 16.8 IU/ml [5.1-45.5] vs. 7.9 IU/ml [4.0-18.0], P<0.00001). High Cy levels were detected in 35.8% of patients. Hyperhomocysteinemia, both in the fasting state and postmethionine loading test, was diagnosed in 90% of cases. The odds ratios for Cy and tHcy levels within the fourth quartile with respect to the other quartiles were markedly increased in renal transplant recipients even after adjustment for prevalent cardiovascular risk factors, glomerular filtration rate, tHcy and, Cy, respectively (Cy: 29.0 micromol/L [95% CI 7.0-111]; tHcy: 29.9 micromol/L [95% CI 7.5-118.1]). Fasting tHcy levels correlated well with PAI-1 (r=0.65; P<0.0001) but not with Cy levels (r=0.10; P=0.4). The prevalence of the MTHFR 677TT genotype in renal transplant recipients was not significantly higher in patients than in controls (mutant allele frequency: 0.48 in patients and 0.47 in controls) and was associated with significantly higher fasting and postmethionine tHcy levels both in controls and patients. After 2 months of vitamin supplementation, tHcy (Pre: 17.0 micromol/L [4.0-68]; Post: 7.5 micromol/L [2.3-21.9]; P<0.0001) and PAI-1 levels (Pre: 16.8 IU/ml [5.1-45.5]; Post: 10 IU/ml [2.0-25]; P<0.001) were significantly decreased, whereas Cy levels showed a small decrease that did not reach statistical significance (Pre: 254 micromol/L [117-466]; Post: 209 micromol/L [168-300]; P=0.3). Patients with the MTHFR 677TT genotype had the major percentage of decrease of tHcy levels with respect to the other genotypes.

CONCLUSION

In conclusion, this study demonstrates the presence of elevated Cy plasma levels in renal transplant recipients. Vitamin supplementation reduces tHcy but not Cy levels, and the amount of decrease seems to be influenced by the MTHFR genotype.

Activation of the immune system and coronary artery disease: the role of anti-endothelial cell antibodies

On the basis of the role of immuno-mediated inflammation in atherosclerosis we investigated, (1) the prevalence of anti-endothelial cell antibodies (AECA) in ischaemic heart disease (IHD); (2) if beta2-glycoprotein I (beta2-GPI) was the target antigen of AECA; (3) the relationship between AECA, tissue factor (TF) and tissue factor pathway inhibitor (TFPI). In 93 consecutive IHD patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and 105 controls AECA were detected by ELISA on human umbilical vein endothelial cells (HUVEC). AECA positive sera were evaluated for anti-beta2-GPI antibodies by ELISA. TF and TFPI plasma levels were assessed by ELISA. Twelve of 93 (12.9%) IHD patients and only one of 105 controls (0.95%) were AECA positive. The prevalence of AECA was higher in unstable angina (UA) than in effort angina (EA) (P=0.01). Three of 12 AECA positive sera resulted positive for anti-beta2-GPI and showed a marked decrease in EC-binding when tested on HUVEC cultured in serum-free medium. The binding was restored by the addition of beta2-GPI. TF and TFPI levels were similar in AECA positive and AECA negative patients. The rate of angiographically documented clinical recurrences was 66.7% in the AECA positive and 14.8% in the AECA negative group (P=0.0004) with a significant relationship between restenosis and AECA (P<0.0001), unchanged by the inclusion of cardiovascular risk factors in the regression model. Our results suggest a 'role' for AECA in the immune-mediated inflammation in UA beta2-GPI is not the only AECA target antigen. AECA are not responsible for high TF and TFPI levels. The high rate of clinical recurrences after PTCA, confirmed by angiography, in AECA positive patients is in line with such a role and suggests further large-scale 'ad hoc' studies.

Hyperhomocysteinemia in renal transplant patients: an independent factor of cardiovascular disease

Hyperhomocysteinemia (Hcy) is an independent factor of cardiovascular disease, which is the main cause of morbidity and mortality both in uremic and kidney transplant patients. The aim of the study was to determine Hcy, plasminogen activator inhibitor (PAI-1) and lipoprotein (a) (Lp(a)) serum levels in 70 patients with a well functioning renal transplant. We also verified whether these levels were modified by a multivitamin therapy. The genetic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) enzyme which plays a main role in Hcy metabolism, was studied as well. We found Hcy, PAI-1 and Lp(a) levels significantly elevated with respect to healthy control subjects. The thermolabile form of the MTHFR enzyme was linked to higher Hcy levels. After a short time on therapy with B6, B12 and folic acid vitamins, Hcy and PAI-1 decreased to normal levels. The authors conclude that high Hcy levels could be a relevant covariate for cardiovascular disease in transplant patients and they suggest that vitamin supplementation be recommended as a part of therapy.

Lipoprotein (a) and anticardiolipin antibodies are risk factors for clinically relevant restenosis after elective balloon percutaneous transluminal coronary angioplasty

Recent reports have shown the importance of new risk factors for cardiovascular disease. We investigated the relationship between Lp(a), fibrinolytic parameters and anticardiolipin antibodies (aCL) and the occurrence of clinical recurrence owing to restenosis after elective balloon percutaneous transluminal coronary angioplasty (PTCA) without stenting. In 167 patients, undergoing PTCA, Lp(a) plasma levels, aCL, euglobulin lysis time (ELT), plasminogen activator inhibitor-1 (PAI-1) activity and tissue-type plasminogen activator (t-PA) plasma levels were evaluated before the procedure. During follow-up 29 patients underwent clinical recurrence due to restenosis. Lp(a) levels were significantly higher in patients with restenosis in comparison to those without (P<0.05); an earlier restenosis was observed in patients with Lp(a) values >450 mg/L. Kaplan-Meier survival estimate showed an earlier occurrence of restenosis in patients with base-line Lp(a)>300 mg/l associated with aCL positivity. High Lp(a) plasma levels play a role in the occurrence of clinical recurrence due to restenosis after elective balloon PTCA without stenting; the association with aCL accelerates the development of restenosis.

Angiotensin-converting enzyme DD genotype, angiotensin type 1 receptor CC genotype, and hyperhomocysteinemia increase first-trimester fetal-loss susceptibility

Complications of pregnancy have been found to be related with thrombophilic polymorphisms that explain about 30% of obstetric complications. We evaluated the angiotensin converting enzyme (ACE) and the angiotensin type 1 receptor (AT1R) gene polymorphisms in the renin-angiotensin system (RAS) as possible risk factors for fetal loss. Fifty-nine women with a history of three or more first-trimester fetal losses and 70 healthy women with a history of normal pregnancies were enrolled in this study. Thrombophilic factors, ACE insertion/deletion (I/D) and AT1R A1166C polymorphisms, prothrombin G20210A and factor V Leiden mutations were analyzed. At univariate and multivariate analysis, a significant association between ACE DD and AT1R CC genotype and fetal loss was observed. The effect of the ACE DD genotype on the risk of fetal loss was higher in AT1R C allele carriers. The prevalence of hyperhomocysteinemia (Hcy) (defined as baseline plasma levels higher than the 95% percentile; cut-off, 10.5 micromol/l per l) was significantly higher in women with fetal loss, and an association between Hcy and fetal loss was detected. All patients showed normal antithrombin, protein C, protein S, and plasminogen activator inhibitor-1 (PAI-1) values. The presence of one risk factor not associated with others was found in 33 out of 59 patients (56%); ACE DD genotype was the most prevalent risk factor. Our results identify new possible predictive markers for fetal loss in RAS polymorphisms and Hcy. Large-scale studies are warranted to attribute clinical relevance to these polymorphisms as risk factors for complicated pregnancies.

High prevalence of mild hyperhomocysteinemia in patients with abdominal aortic aneurysm

PURPOSE

In vitro studies have recently demonstrated that homocysteine interacts with the aortic wall by inducing both elastolysis and endothelial perturbation. The aim of this study was to evaluate homocysteine plasma levels and their relationships with aortic diameter and endothelial damage in patients with abdominal aortic aneurysm.

SUBJECTS AND METHODS

Fifty-eight consecutive male patients (mean age, 69.5 +/- 6.6 years; age range, 49-78 years) who underwent abdominal aortic aneurysm surgery were enrolled in the study. Twenty-two of 58 patients had no clinical or instrumental evidence of atherosclerosis. Sixty control subjects were age matched and sex matched with the patients. In all of the subjects, we evaluated total homocysteine and thrombomodulin plasma levels and the distribution of the C677T methylenetetrahydrofolate reductase gene mutation.

RESULTS

Hyperhomocysteinemia was found in 26 (48%) of the 58 patients with abdominal aortic aneurysm, and homocysteine plasma levels were significantly higher in patients than in control subjects (15.7 +/- 6.5 micromol/L vs 9.6 +/- 3.9 micromol/L; P <. 0001). In addition, the subgroup of patients with abdominal aortic aneurysm who did not show evidence of atherosclerosis showed homocysteine plasma levels significantly higher than those in the controls (14.8 +/- 6.1 micromol/L vs 9.6 +/- 3.9 micromol/L; P <. 001). A larger aneurysmal size was detected in hyperhomocysteinemic patients than in those with normal homocysteine plasma levels (5.09 +/- 0.84 cm vs 5.79 +/- 1.5 cm; P <.05). The genotype distribution of the C677T methylenetetrahydrofolate reductase mutation was as follows: TT 21%, TC 55%, and CC 24% in the patients; TT 10%, TC 58%, and CC 32% in the controls. Moreover, in patients a significant correlation (P <.005) between homocysteine plasma level and 677TT methylenetetrahydrofolate reductase genotype was found. Thrombomodulin plasma levels were significantly higher (P <.00005) in patients (median, 30 ng/mL; range, 10-164 ng/mL) than in controls (median, 19 ng/mL; range, 13-44 ng/mL), and thrombomodulin levels were significantly higher (P <.005) in hyperhomocysteinemic patients (median, 39.5 ng/mL; range, 15-164 ng/mL) than in normohomocysteinemic patients (median, 27.5 ng/mL; range, 10-85 ng/mL). In addition, in patients with abdominal aortic aneurysm, a direct significant correlation (P <.005) was found between homocysteine and thrombomodulin.

CONCLUSIONS

These data indicate an association between the presence of AAA in patients selected for surgical treatment of AAA and elevated homocysteine plasma levels and suggest that homocysteine may induce endothelial perturbation and stimulation in these patients.

Usefulness of screening for congenital or acquired hemostatic abnormalities in women with previous complicated pregnancies

Activated protein C resistance (APCR) is a common cause of familial thrombophilia and venous thrombosis. The aim of the study was to investigate the prevalence of APCR associated with factor V Leiden mutation and its relevance in comparison to other risk factors for thromboembolic disorders in women with a history of previous complicated pregnancies (history of fetal loss in the second and third trimester n = 34, preeclampsia n = 46). The frequency of APCR was significantly higher in women with a history of fetal loss and preeclampsia (23.5 and 26.1%, respectively) compared with a control group (3.8%). The prevalence of antithrombin, protein C and protein S deficiencies and the presence of antiphospholipid antibodies were also investigated: the prevalence of at least one disorder was 41.2% in the group with previous fetal loss, 37.0% in the group with previous preeclampsia and 7.5% in the control group.

Tissue factor and homocysteine levels in ischemic heart disease are associated with angiographically documented clinical recurrences after coronary angioplasty

BACKGROUND

In ischemic heart disease (IHD) patients high plasma levels of Tissue Factor (TF), the trigger of coagulation cascade, are present. Homocysteine (Hcy) is a risk factor for coronary artery disease, and several different pathophysiological mechanisms by which Hcy may play a role in thrombus formation have been postulated in "in vitro" studies. We investigated the "in vivo" role of Hcy in affecting plasma levels of TF, its inhibitor Tissue Factor Pathway Inhibitor (TFPI) and hypercoagulability.

METHODS AND RESULTS

We investigated 119 IHD patients who underwent PTCA and compared them with 103 healthy subjects. TF, TFPI, Thrombin-Antithrombin complexes (TAT) and Hcy levels were significantly higher in the patients than in the controls. A positive correlation was found between Hcy and TF (r = 0.54; p < 0.0001), Hcy and TFPI (r = 0.26; p <0.05) as well as Hcy and TAT (r = 0.33; p <0.0001) levels. An inverse correlation existed between folate intake and Hcy levels (r = -0.28; p = 0.001). Hcy levels within the first quartile and in the highest quartile were associated with a lower (p < 0.001) and higher (p <0.0001) rate of clinical recurrences, respectively. Patients with TF values in the first quartile had a lower rate of angiographically documented clinical recurrences as compared to those in the fourth quartile (p <0.01); those in the highest quartile of TF showed a higher rate of recurrences (p = 0.001). Multivariate analysis confirmed these results (first quartile of Hcy: OR 0.02, C1 0.002-0.27; fourth quartile of Hcy: OR 36.5, C1 3.6-365/first quartile of TF: OR 0.006, C1 0.001-0.44; fourth quartile of TF: OR 16.4, C1 3.0 - 90.0), also after adjustment for risk factors and Hcy and TF respectively.

CONCLUSIONS

In this study we show that TF, TFPI and TAT levels are correlated with Hcy plasma levels in IHD patients, providing evidence of an "in vivo" pathophysiological mechanism of hyperhomocysteinemia. The observed association between angiographically documented clinical recurrences and TF and Hcy values awaits confirmation in studies designated to evaluate this issue on a larger number of patients.

The influence of smoking on von Willebrand factor is already manifest in healthy adolescent females: the Floren-teen (Florence Teenager) Study

The early onset of atherosclerosis and the involvement of physiological biochemical, and environmental factors in its pathogenesis is well documented. Few data are available on the role of risk factors related to hemostasis in the pathogenesis of atherosclerosis in the young and, in particular, little information is available on adolescent populations. In the Study of Preventive Medicine and Education Program (Floren-teen Study), von Willebrand factor, a risk factor for cardiovascular disorder, was studied, together with classical cardiovascular risk factors, in apparently healthy students from two high schools in Florence. Familial and personal history, physical examination, and cardiovascular risk factors were evaluated in 144 students (aged 17-19 years). Blood was withdrawn to assess von Willebrand factor (ELISA) and lipid parameters. Levels of von Willebrand factor were significantly higher (P<0.044) in smokers than in nonsmokers and were correlated with the number of cigarettes per day in the whole group (P=0.01) and in females (P=0.006). In females a positive correlation was observed between von Willebrand factor and high-density lipoprotein cholesterol (P=0.0365). There was no significant correlation between von Willebrand factor and blood pressure or between von Willebrand factor and physical activity. In conclusion, this study shows an association between levels of von Willebrand factor and smoking habits and is the first show that even a brief period of smoking affects levels of von Willebrand factor in healthy adolescent females independently of other risk factors. These results stress the relevance of extending prevention programs to reduce smoking in high school students.

Effect of tourniquet use on activation of coagulation in total knee replacement

Total knee replacement often is performed with tourniquet application. The advantages of a dry field, including fixation, are well known, but it still is debatable if tourniquet application increases deep vein thrombosis. Measurement of coagulation markers is a well accepted method of studying thrombogenesis activation intraoperatively and postoperatively. Twenty patients undergoing total knee replacement with subarachnoid anesthesia were assigned randomly to two groups: either with tourniquet application (Group I) or without tourniquet application (Group II). There were no differences between patients in the two groups in terms of age, gender, diagnosis (all had osteoarthritis), operative time, and total (intraoperative and postoperative) blood loss. Markers for thrombin generation and fibrinolysis were measured. Blood samples were drawn at four times: baseline before the operation; after bone cuts; after cement fixation (Group II) or 2 minutes after tourniquet deflation (Group I); and 1 hour after surgery. Markers of thrombin generation and fibrinolysis showed a significant increase from baseline in all the patients. In Group II these markers started to increase during surgery, whereas in Group I the increase occurred at the end of the procedure when the tourniquet was deflated. The total amount of thrombin generation was significantly higher in Group II (without tourniquet), whereas fibrinolysis was significantly greater in Group I. Total knee replacement is accompanied by a hypercoagulative state with or without the use of a tourniquet, but it seems to be higher when the tourniquet is not used. In addition, tourniquet application may increase fibrinolysis.

Videolaparoscopic cholecystectomy induces a hemostasis activation of lower grade than does open surgery

BACKGROUND

Tissue injury after trauma and surgery may induce alterations in blood coagulation and fibrinolysis, and the hypercoagulable state observed after surgery can be associated with the risk of postoperative thromboembolic complications. Recently, videolaparoscopic (VLPS) cholecystectomy has been introduced, and its advantages over the open procedure seem related to the reduced surgical trauma. The aim of this study was to investigate hemostatic system alterations in patients who undergo open and VLPS cholecystectomy.

METHODS

Fibrinogen, prothrombin fragment F1+2, D-dimer, and plasminogen activator inhibitor type-1 (PAI-1) activity was determined in 10 patients who underwent open (group A) and 10 patients who underwent VLPS cholecystectomy (group B), respectively. Blood samples were obtained the day of surgery in the morning (B1), after anesthesia (A1), 1 hour after the start of surgery (S1), then 30 min (E.05) and 24 h (E.24) after the surgery.

RESULTS

No significant differences were observed in baseline values between groups A and B for the parameters investigated. At 24 h after surgery, fibrinogen increased significantly (p < 0.05) in group A and also was significantly higher than in group B (p < 0.05). In group A, a marked increase in F1+2 levels (p < 0.01) was observed in all the samples, with the maximum values on the first day after surgery (3.7 nmol/l; 1.2-6.0 nmol/l), whereas in group B, a slight but significant increase in F1+2 levels (2.1 nmol/l; 1.1-3.9 nmol/l; p < 0.01) was observed only 30 min after the end of surgery. In both groups A and B, D-dimer markedly increased after surgery, without statistical significant differences between the two groups at any time. The PAI-1 activity plasma levels remained in the normal range during and after surgery in both groups.

CONCLUSIONS

These results indicate that VLPS surgery induces an activation of the clotting system that, although of low degree and short duration, can lead to a transient prothrombotic state.