[Inherited bleeding disorders in adolescents with excessive menstrual bleeding. Should we evaluate the fibrinolytic pathway?] / Trastornos hereditarios de la coagulación en adolescentes con sangrado menstrual excesivo, ¿debemos evaluar la vía fibrinolítica?

INTRODUCTION: Heavy Menstrual Bleeding (EMB) is a frequent problem in adolescence. The prevalence of inherited bleeding disorders (IBD) as a cause of EMB is not well established and the involvement of fibri nolytic pathway defects has been poorly explored. OBJECTIVE: To determine the prevalence of IBD and fibrinolysis defects in adolescents with EMBs. PATIENTS AND METHOD: 93 adolescents (11 to 18 years old) were included. Personal and family history of bleeding were obtained through a standard ized questionnaire. The following lab tests were performed: prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor quantification, and platelet count and function. Those patients who were not diagnosed with IBD were further evaluated with clot lysis time assay. RESULTS: 41 patients (44%) were diagnosed as IBD (Von Willebrand disease n = 28, platelet func tion defects n=8, mild hemophilia n = 5. Decreased clot lysis time was found in 31 patients. 54% of patients diagnosed with IBD had EMB as the first hemorrhagic manifestation. CONCLUSION: These results support the need to evaluate the coagulation process, including the fibrinolytic pathway in the study of adolescents with EMB.

International collaborative study for the calibration of proposed International Standards for thromboplastin, rabbit, plain, and for thromboplastin, recombinant, human, plain.

Essentials Two candidate International Standards for thromboplastin (coded RBT/16 and rTF/16) are proposed. International Sensitivity Index (ISI) of proposed standards was assessed in a 20-centre study. The mean ISI for RBT/16 was 1.21 with a between-centre coefficient of variation of 4.6%. The mean ISI for rTF/16 was 1.11 with a between-centre coefficient of variation of 5.7%. SUMMARY: Background The availability of International Standards for thromboplastin is essential for the calibration of routine reagents and hence the calculation of the International Normalized Ratio (INR). Stocks of the current Fourth International Standards are running low. Candidate replacement materials have been prepared. This article describes the calibration of the proposed Fifth International Standards for thromboplastin, rabbit, plain (coded RBT/16) and for thromboplastin, recombinant, human, plain (coded rTF/16). Methods An international collaborative study was carried out for the assignment of International Sensitivity Indexes (ISIs) to the candidate materials, according to the World Health Organization (WHO) guidelines for thromboplastins and plasma used to control oral anticoagulant therapy with vitamin K antagonists. Results Results were obtained from 20 laboratories. In several cases, deviations from the ISI calibration model were observed, but the average INR deviation attributabled to the model was not greater than 10%. Only valid ISI assessments were used to calculate the mean ISI for each candidate. The mean ISI for RBT/16 was 1.21 (between-laboratory coefficient of variation [CV]: 4.6%), and the mean ISI for rTF/16 was 1.11 (between-laboratory CV: 5.7%). Conclusions The between-laboratory variation of the ISI for candidate material RBT/16 was similar to that of the Fourth International Standard (RBT/05), and the between-laboratory variation of the ISI for candidate material rTF/16 was slightly higher than that of the Fourth International Standard (rTF/09). The candidate materials have been accepted by WHO as the Fifth International Standards for thromboplastin, rabbit plain, and thromboplastin, recombinant, human, plain.

Trastornos hereditarios de la coagulación en adolescentes con sangrado menstrual excesivo, ¿debemos evaluar la vía fibrinolítica? / Inherited bleeding disorders in adolescents with excessive menstrual bleeding: should we evaluate the fibrinolytic pathway?

Resumen: Introducción: El Sangrado Menstrual Excesivo (SME) es un problema frecuente en la adolescencia. La prevalencia de trastornos hereditarios de la coagulación (THC) como causa del SME no está bien establecida y la participación de defectos de la vía fibrinolítica ha sido poco explorada. Objetivo: Determinar la prevalencia de THC y defectos de la fibrinólisis en adolescentes con SME. Pacientes y Método: Se incluyeron 93 adolescentes, edad 11 a 18 años. Los antecedentes personales y familiares de sangra do se obtuvieron con un cuestionario estandarizado. Se controló exámenes: tiempo de protrom- bina (TP), tiempo de tromboplastina parcial activada (TTPa), estudio del factor Von Willebrand, recuento y función plaquetaria. Los pacientes que no fueron diagnosticados como THC, se evaluaron adicionalmente con el tiempo de lisis del coágulo. Resultados: 41 pacientes (44%) fueron diagnos ticados como THC: Enfermedad de Von Willebrand n = 28, defectos de la función plaquetaria n = 8, hemofilia leve n = 5. Se confirmó disminución del tiempo de lisis del coágulo en 31 pacientes. El 54% de pacientes diagnosticado como THC, tuvo SME como la primera manifestación hemorrágica. Conclusión: Estos resultados apoyan la necesidad de evaluación de la coagulación, incluyendo la vía fibrinolítica, en el estudio de adolescentes con SME.

Abstract: Introduction: Heavy Menstrual Bleeding (EMB) is a frequent problem in adolescence. The prevalence of inherited bleeding disorders (IBD) as a cause of EMB is not well established and the involvement of fibri nolytic pathway defects has been poorly explored. Objective: To determine the prevalence of IBD and fibrinolysis defects in adolescents with EMBs. Patients and Method: 93 adolescents (11 to 18 years old) were included. Personal and family history of bleeding were obtained through a standard ized questionnaire. The following lab tests were performed: prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor quantification, and platelet count and function. Those patients who were not diagnosed with IBD were further evaluated with clot lysis time assay. Results: 41 patients (44%) were diagnosed as IBD (Von Willebrand disease n = 28, platelet func tion defects n=8, mild hemophilia n = 5. Decreased clot lysis time was found in 31 patients. 54% of patients diagnosed with IBD had EMB as the first hemorrhagic manifestation. Conclusion: These results support the need to evaluate the coagulation process, including the fibrinolytic pathway in the study of adolescents with EMB.

Template bleeding time and PFA-100 have low sensitivity to screen patients with hereditary mucocutaneous hemorrhages: comparative study in 148 patients.

OBJECTIVES AND PATIENTS: We compared the template bleeding time (BT) and closure time (CT) in the PFA-100 as screening tests in 148 consecutive patients with unequivocal mucocutaneous bleeding and positive family history. EXCLUSION CRITERIA: drug intake, concomitant diseases including minor infections, low platelet count, diseases of secondary hemostasis. RESULTS: Type 1 von Willebrand disease (VWD-1) was diagnosed in 26 patients, primary platelet secretion defect (PSD) in 33, VWD-1 + PSD in nine, whereas 80 patients did not comply with the criteria for known hemostatic disorders (UD, unknown diagnosis). BT and CT were prolonged in 35.8% and 29.7% of all the patients, respectively (P = 0.23). Sensitivity increased to 48% if an abnormality of BT and/or CT was considered. Same comparisons for BT and CT in each diagnostic category were, respectively: 42 vs. 61.5% in VWD-1 (P = 0.18), 42 vs. 24% in platelet secretion defects (P = 0.11), 67 vs. 89% in VWD-1 + PSD (P = 0.50), and 27.5 vs. 15% in UD (P = 0.06). CONCLUSION: Both tests were relatively insensitive and not significantly different in detecting incoming patients with mucocutaneous hemorrhages. In patients with VWD-1, the PFA-100 performed slightly better, whereas the opposite occurred in those patients with platelet secretion defects. In the UD group, both tests lost sensitivity, but the BT detected 1.8 times more patients than the PFA-100. Given the large proportion of undiagnosed bleeders and the overall low sensitivity of these tests, clinical decisions still rely on the medical history and etiological diagnosis of the bleeding disorder.

Hemostatic disorder of uremia: the platelet defect, main determinant of the prolonged bleeding time, is correlated with indices of activation of coagulation and fibrinolysis.

Several parameters of primary hemostasis and markers of activation of coagulation and fibrinolysis were measured in 48 patients with severe (creatinine clearance < 20 ml/min) chronic renal failure (CRF) without dialysis and disease or drugs affecting hemostasis. Bleeding time (BT) was prolonged in 25/48 patients, and was correlated with age of patients, severity of renal failure, hematocrit, impairment in platelet aggregation-secretion and decrease in platelet ATP content. Defects in von Willebrand factor played no role in the prolongation of the BT. Multivariate analysis showed that only platelet dysfunction and severity of renal disease were independent predictors of the BT in uremia. The platelet functional disorder was significantly correlated with a reduction in platelet ATP and ADP. High levels of plasma thrombin-antithrombin complexes (TAT), prothrombin fragment F1 + 2, fibrinogen and factor VIIc were observed in patients with CRF, as described in prethrombotic states. Plasmin-antiplasmin complexes (PAP), fibrinogen and fibrin degradation products (FgDP, FnDP) were significantly increased, and the activity of plasminogen activator inhibitor (PAI-1) was slightly reduced, denoting an activation of fibrinolysis. A negative correlation was found between platelet levels of ATP and ADP with plasma TAT, F1 + 2 and PAP. Furthermore, plasma PAI-1 activity was negatively correlated with the BT and was lower in patients with prolonged BT as compared with controls and patients with normal BT. These links between primary hemostasis and activation of coagulation and fibrinolysis suggest that increased intravascular generation of thrombin and/or plasmin is an important mediator of the defects in primary hemostasis, prolongation of the BT and, probably, bleeding in CRF.

Vegetarians and cardiovascular risk factors: hemostasis, inflammatory markers and plasma homocysteine.

We studied hemostatic and inflammatory cardiovascular risk factors (CVRF), and total plasma homocysteine (tHcy) in 26 vegetarians (23 lacto- or ovolactovegetarians and 3 vegans), matched by age, sex and socioeconomic status with omnivorous controls. Vegetarians had significantly lower proportion of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in plasma lipids, significantly shortened bleeding time, and increased blood platelet count and in vitro platelet function (aggregation and secretion). Plasma levels of all coagulation or fibrinolytic factors and natural inhibitors synthesized in the liver were lower in vegetarians than in controls. Whereas for some factors this decrease was statistically significant (fibrinogen, factor VIIc, antithrombin III, protein S, plasminogen) for the remaining (factors VIIIc, Vc, prothrombin, protein C) a trend in the same direction was found. For hemostatic proteins of predominantly extrahepatic origin (von Willebrand factor. tPA, PAI-1) this tendency was not present. No significant differences in inflammatory proteins (C-reactive protein and alpha1-protease inhibitor) were detected in both groups. tHcy was significantly increased in vegetarians, and correlated only with cobalamin levels. The increased platelet function and tHcy found in vegetarians may counteract the known cardiovascular health benefits of vegetarian diet (VD).

Tranexamic acid inhibits fibrinolysis, shortens the bleeding time and improves platelet function in patients with chronic renal failure.

BACKGROUND: A defect in platelet function is the main determinant of the prolonged bleeding time in chronic renal failure (CRF). We previously reported a significant correlation between platelet abnormalities and elevated plasma markers of plasmin and thrombin generation. Our aim was to explore the effect of inhibiting both plasmin action with tranexamic acid (TA) and thrombin production with low molecular weight heparin (LMWH), on the bleeding time (BT) and platelet function in patients with CRF. METHODS: 37 patients with CRF (mean creatinine 8.6 +/- 4.4 mg/dl) under conservative treatment, with prolonged BT, entered this study and received TA during 6 days, with (n = 24) and without LMWH (n = 13). BT, platelet aggregation/secretion, platelet granule contents, von Willebrand factor and parameters of coagulation and fibrinolysis were recorded before and at the end of treatment. RESULTS: The BT was shortened in 26/37 (67%) patients. This effect was associated with significant improvement of platelet aggregation and secretion, with decrease to a normal range of fibrin/fibrinogen degradation products, mild increase in plasmin-antiplasmin complexes and pronounced reduction of circulating plasminogen. No differences were seen among patients with or without LMWH. No serious side effects or complications were observed. INTERPRETATION: These findings indicate that the activation of fibrinolysis plays a significant role in the defect of primary hemostasis in patients with CRF. Inhibition of plasmin activity with TA shortens the BT and improves platelet function in the majority of patients with severe disease.

Cardiovascular risk factors in vegetarians. Normalization of hyperhomocysteinemia with vitamin B(12) and reduction of platelet aggregation with n-3 fatty acids.

Hyperhomocysteinemia in association with vitamin B(12) deficiency, and increased platelet aggregation, probably due to dietary lack of n-3 fatty acids, constitute cardiovascular risk factors frequently observed in vegetarians. We tested if administration of vitamin B(12) normalizes the concentration of total plasma homocysteine, and if intake of eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) fatty acids modulates platelet function in a population of lactoovovegetarians. One week after a single intramuscular injection of cyanocobalamin (10000 microg) in 18 individuals, serum vitamin B(12) increased from 149+/-63 pg/mL to 532+/-204 pg/mL (p<0.0001) and total tHcy dropped from 12.4+/-4.7 to 7.9+/-3.1 micromol/L (p<0. 0001). Ten of fourteen of these vegetarians completed an 8-week supplementation with 700 mg/day of each eicosapentaenoic and docosahexaenoic acids. Increased incorporation of these fatty acids into plasma lipids was observed in all of them, together with a significant reduction in maximum percentage or slope of platelet aggregation with all the agonists tested (ADP, epinephrin, collagen, arachidonic acid). No significant change in bleeding time was observed after n-3 fatty acid trial. Supplementation with vitamin B(12) and n-3 fatty acids corrects hyperhomocysteinemia and reduces platelet reactivity to agonists in vegetarians. Whether this supplementation improves the already reduced cardiovascular morbidity and mortality associated with vegetarian diet has yet to be demonstrated.

Endothelial cell markers in chronic uremia: relationship with hemostatic defects and severity of renal failure.

Plasma von Willebrand factor antigen, soluble thrombomodulin, and tissue factor were increased in 31 patients with severe chronic renal failure (creatinine clearance <20 ml/min) under conservative treatment, whereas plasminogen activator inhibitor antigen did not differ significantly from healthy controls. No correlation among plasma levels of these proteins was found. Three patterns of relationship between endothelial cell markers and hemostatic defects were identified: 1) Plasma thrombomodulin, a marker of endothelium damage, was found an independent predictor of bleeding time and platelet aggregation, and secretion defects, and was also related to the severity of renal failure; 2) von Willebrand factor antigen, an index of endothelial cell activation and secretion, was significantly correlated with intravascular markers of thrombin and plasmin generation and with platelet adenosine triphosphate content, but not with plasma creatinine levels; and 3) tissue factor and plasminogen activator inhibitor antigen levels were not statistically correlated with the diverse hemostatic defects. Activation of coagulation and fibrinolysis, secondary to endothelial cell activation, appearing early during the evolution of chronic renal failure, is pathogenically related to the platelet dysfunction, and probably to development of atherosclerosis and thrombotic events in this disease. The progression of chronic renal failure, through endothelial cell damage, would lead to aggravation of the platelet functional defect potentiating the hemorrhagic risk.

Mediterranean diet, but not red wine, is associated with beneficial changes in primary haemostasis.

OBJECTIVE: (1) To compare the effect of an alcohol-free Mediterranean-type diet (MD) and a high-fat diet (HFD) on variables of primary haemostasis (bleeding time, plasma von Willebrand factor and platelet aggregation/secretion). (2) To test whether red wine supplementation modified these variables, independently of the diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each consisting of 21 healthy male university students (22+/-3.4 y), received either MD or HFD during 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline (T0) and T30, T60 and T90-day samples were drawn. Bleeding time was measured before (day 30) and after (day 60) wine supplementation. No drop out from the study was experienced. SETTING: University campus and outpatient nutrition clinic. RESULTS: All baseline (day 0) variables did not differ significantly between study groups. On day 30, individuals on MD had significantly higher levels of plasma beta-carotene, folate, ascorbate, and eicosapentaenoic acid in plasma lipid fractions, than those on HFD. Total plasma cholesterol, HDL and LDL did not change significantly in either study group at any time point. After 30 days on each diet, individuals on MD had longer bleeding time (BT) than those on HFD (7.6+/-2.8 vs 5.8+/-1.7 min; P=0.017). BT did not change significantly after I month of wine supplementation (7.1+/-2.0 vs 5.5+/-2.0 min, respectively). Plasma von Willebrand factor (vWF : Ag) on day 0 was 89+/-40 and 111+/-70% in MD and HFD groups, respectively (P=0.21). These values did not change significantly at 30, 60 or 90 days. MD intake was associated with an increase in platelet serotonin secretion (P=0.02) and a marginal increase in platelet aggregation after stimulation with epinephrine (P=0.07). Wine intake resulted in a marginal decrease in platelet (14)C-5-HT secretion with 4 micro M ADP (P=0.07). However, both platelet aggregation and secretion were consistently increased when using collagen as agonist (1 and 2 micro g/ml, P=0.01). CONCLUSION: The longer BT in individuals on MD, obtained independently of red wine, denotes less interaction of platelets with the vascular wall, which could be beneficial from the point of view of cardiovascular (CV) risk. This effect is not explained by changes in the measured haemostatic determinants of BT (plasma vWF, ex vivo platelet function), and might be attributed to other as yet unknown vascular factors. Moderate consumption of red wine results in a significant increase in ex vivo platelet aggregation and secretion after stimulation with collagen. This observation contradicts previous reports, although further studies are required to elucidate the influence of this finding on CV risk.

Complementary effects of Mediterranean diet and moderate red wine intake on haemostatic cardiovascular risk factors.

OBJECTIVES: To compare the effect of alcohol-free Mediterranean-type diet (MD) and high-fat diet (HFD) on plasma concentration of emergent haemostatic cardiovascular risk factors (HCVRF). Also, to test if red wine supplementation modifies HCVRF, independent of diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each of 21 healthy male university students (22+/-3.4 y), received either MD or HFD for 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline and T30, T60 and T90-day samples were drawn. No drop out from the study was observed. SETTING: University campus and outpatient nutrition clinic. RESULTS: Volunteers on HFD at T30 had increases in pro-coagulants fibrinogen (22%), factor VIIc (9%), and factor VIIIc (4%), and decreases in natural anticoagulants antithrombin III (3%), protein C (11%) and protein S (6%) and of 20% in plasminogen activator inhibitor-1. At the same time, individuals on MD had increases in fibrinogen (4%), antithrombin III (5%), protein C (3%), protein S (2.7%), and decreases in factor VIIIc (9%), and plasminogen activator inhibitor-1 (21%). After adjusting by baseline values, MD was associated with lower plasma fibrinogen (P=0.03), factor VIIc (P=0.034) and factor VIIIc (P=0.0057) and with higher levels of protein S (P=0.013). Red wine supplementation, in both diets, resulted in decreased plasma fibrinogen (P=0.001) and factor VIIc (P=0.05), and increased tissue plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor-1 antigen (P=0.0003). Wine consumption was also associated with significantly (P=0.01) divergent effects on antithrombin III: it decreased by 10% in individuals on HFD but increased slightly in those on MD. No effects of diet or wine were detected in plasma protein C and C-reactive protein. CONCLUSION: MD and moderate consumption of red wine have complementary, mostly beneficial effects on HCVRF.

Quantitative impact of using different criteria for the laboratory diagnosis of type 1 von Willebrand disease.

INTRODUCTION: Only ± 50% of patients with type 1 von Willebrand disease (VWD) have recognized molecular defects and diagnosis still rests on demonstrating low plasma von Willebrand factor (VWF) protein/function. However, no generalized consensus exists regarding the type and number of VWF variables that should be considered for diagnosis. AIM: To compare the quantitative impact of four different criteria to diagnose type 1 VWD. METHODS: We tested four laboratory criteria on 4298 laboratory studies during a 5-year period. The first was the National Heart, Lung, and Blood Institute recommendation, which diagnoses type 1 VWD with plasma VWF antigen (VWF:Ag) and VWF ristocetin cofactor (VWF:RCo) < 30 IU dL(-1) and possible VWD/'low VWF' with values between 30 and 50 IU dL(-1) . Second, diagnosis was established when two of three variables, VWF:Ag, VWF:RCo, VWF collagen binding assay (VWF:CB), were ≤ 2.5th percentile. Diagnostic criterion for possible VWD/'low VWF' using percentiles was also described. The third criterion (European Group on von Willebrand Disease, EUVWD), uses a plasma level of VWF:RCo (or VWF:CB) ≤ 40 IU dL(-1) for diagnosis. Finally, the Zimmerman Program for the Molecular and Clinical Biology of VWD (ZPMCBVWD) diagnoses VWD if VWF:Ag or VWF:RCo are ≤ 40 IU dL(-1) . RESULTS: The three assays had high correlation and excellent agreement at levels < 120 IU dL(-1) . The National Heart, Lung, and Blood Institute recommendation was followed to diagnose 122 (2.8%) patients with type 1 VWD and 704 (16.4%) with possible VWD/'low VWF.' Using percentiles, the diagnosis of type 1 VWD increased to 280 (6.5%) patients; 169 (3.9%) patients had possible VWD and 180 (4.2%) patients had 'low VWF.' Diagnoses using EUVWD and ZPMCBVWD criteria increased to 339 (7.9%) and 357 (8.3%) patients, respectively. DISCUSSION: Identical data, analyzed using different criteria, led to almost three-fold difference (2.8-8.3%) in diagnostic rate. This increase is mostly explained by increasing the cut-off values of VWF measurements from < 30 to ≈ 40 IU dL(-1) . Further refinement of the laboratory diagnosis of type 1 VWD is a priority.

An adenine insertion in exon 6 of human GP6 generates a truncated protein associated with a bleeding disorder in four Chilean families.

BACKGROUND: Glycoprotein VI (GPVI), 60-65 kDa, is a major collagen receptor on platelet membranes involved in adhesive and signaling responses. Mice lacking GPVI have impaired platelet response to collagen and defective primary adhesion and subsequent thrombus formation. Complete or partial deficiency of GPVI in humans is a rare condition presenting as a mild bleeding disorder. The defect in most of the reported patients is acquired and associated with other diseases. To date, only two patients have been characterized at the molecular level who carry different compound heterozygous mutations in the GP6 gene. OBJECTIVE: To report four unrelated patients from non-consanguineous families who presented with mucocutaneous bleeding. They had absent platelet aggregation and (14) C-5-HT secretion with collagen, convulxin and collagen-related peptide. RESULTS: Flow cytometry and immunofluorescence-confocal microscopy showed an absence of GPVI in non-permeabilized platelets. All the patients had an adenine insertion in exon 6 (c.711_712insA), changing the reading frame and generating a premature 'stop codon' in site 242 of the protein. The mutation predicts the synthesis of the truncated protein before the trans-membrane domain, corresponding to a band of ≈49 kDa observed in western blots and in permeabilized platelets by immunofluorescence. Platelet mRNA from all the patients was sequenced and contained the corresponding adenine insertion. Heterozygous relatives had no pathological bleeding, normal response to collagen and convulxin and intermediate membrane expression of GPVI. CONCLUSIONS: The identification of four unrelated homozygous patients with an identical defect suggests that inherited GPVI deficiency is more frequent than previously suspected, at least in Chile.

Increased activation of protein C, but lower plasma levels of free, activated protein C in uraemic patients: relationship with systemic inflammation and haemostatic activation.

Chronic renal failure (CRF) courses with both systemic inflammatory reaction and haemostatic activation. We explored the relationship of these processes with plasma levels of free, activated protein C (APC) and complexes of APC with its inhibitors in patients with CRF under conservative treatment. Plasma concentrations of inflammatory cytokines [tumour necrosis factor alpha (TNFalpha) and interleukin 8], acute-phase proteins (C-reactive protein, fibrinogen, alpha1-anti-trypsin and von Willebrand factor), and markers of haemostatic activation (thrombin-anti-thrombin complexes, plasmin-anti-plasmin complexes, and fibrin and fibrinogen degradation products) were higher in patients than in controls. Inflammatory and haemostatic markers were significantly and positively correlated. Total plasma APC and APC:alpha1-anti-trypsin (alpha1AT) complexes were 44% and 75% higher in patients than in controls (P = 0.0001), whereas free APC was 20% lower (P < 0.015). No significant difference was observed in APC:protein C inhibitor (PCI) complexes between both groups. The free/total APC ratio was significantly lower in patients than in controls (P < 0.0001). Total plasma APC and APC:alpha1AT were positively correlated with activation markers of haemostasis and acute-phase proteins, whereas free APC was inversely correlated with plasma levels of creatinine, acute-phase proteins and fibrin degradation products (FnDP). Systemic inflammation and activation of haemostasis are interrelated processes in CRF. APC generation was increased in response to elevated thrombin production, but the inflammatory reaction, associated with increased synthesis of alpha1AT, reduced its anticoagulant effect. Lower free plasma APC in CRF may be pathogenically associated with atherothrombosis, a major cause of death in this disease.

Inflammation, not hyperhomocysteinemia, is related to oxidative stress and hemostatic and endothelial dysfunction in uremia.

BACKGROUND: Several cardiovascular risk factors are present in patients with chronic renal failure (CRF), among which are systemic inflammation and hyperhomocysteinemia. Increased oxidative stress, endothelial activation/dysfunction, and coagulation activation are considered integral components of the inflammatory response, but have also been proposed as mediators of plasma homocysteine (tHcy)-induced cell damage. Using correlation analysis, we assessed the relative contributions of inflammation and hyperhomocysteinemia in the abnormal oxidative stress, endothelial activation/dysfunction, and hemostasis activation in patients with CRF. METHODS: The relationships of inflammatory proteins and tHcy with plasma markers of these processes were studied in 64 patients with CRF (serum creatinine 526 +/- 319 micromol/L) on conservative treatment, comparing the results with healthy controls (N = 15 to 40, depending on the measured variable) of similar sex and age. RESULTS: Patients had significant increases in inflammatory cytokines (TNF-alpha and IL-8) and acute-phase proteins (C-reactive protein, fibrinogen and alpha1-antitrypsin). tHcy was increased in 87.5% of patients (mean = 27.1 micromol/L, range 6.5 to 118). Patients had significant increases in (1) indices of oxidative stress: TBARS (thiobarbituric acid-reactive species), a marker of lipid peroxidation and AOPP (advanced oxidation protein products), a marker of protein oxidation; (2) endothelial cell markers such as von Willebrand factor (vWF:Ag), soluble ICAM-1 and soluble thrombomodulin (sTM); (3) markers of intravascular thrombin generation: thrombin-antithrombin complexes (TAT) and prothrombin fragment F(1+2) (PF(1+2)); and (4) indices of activation of fibrinolysis: plasmin-antiplasmin complexes (PAP), fibrin degradation products (FnDP) and fibrinogen degradation products (FgDP). tHcy was significantly correlated with plasma creatinine (r = 0.29, P < 0.018) and with serum folate (r = -0.38, P < 0.002). However, no significant correlations were observed between tHcy and TBARS, AOPP, vWF:Ag, sICAM-1, sTM, TAT, F(1+2), sTF, PAP, FnDP, and FgDP. Conversely, acute-phase proteins showed significant, positive correlations with most markers of oxidative stress, endothelial dysfunction and hemostatic activation. CONCLUSIONS: Systemic inflammation, which is closely associated with augmented oxidative stress, endothelial cell dysfunction and hemostatic activation, emerges as a major cardiovascular risk factor in CRF. tHcy is unrelated to these events. Thus, alternative mechanisms through which hyperhomocysteinemia could predispose to vascular lesion and thrombotic events in CRF needs to be investigated.