[Genetic thrombophilia and markers of endothelial activation in patients with preeclampsia]. / Trombofilia genética y marcadores de activación endotelial en pacientes con preeclampsia.

BACKGROUND: The presence of thrombosis in preeclampsia suggests that endothelial function could play an important role in its pathogenesis. OBJECTIVE: Determine the association between markers of genetic thrombophilia, endothelial activation and preeclampsia. MATERIAL AND METHOD: Prospective study of cases and controls to determine the factor V Leiden existence, protrombin G20210A, methylenetetrahydrofolate reductase C677T, activated protein C resistance and levels of von Willebrand factor and the sFlt1 receptor were determined in 28 women with preeclampsia and 41 pregnant controls. RESULTS: Methylenetetrahydrofolate reductase C677T had a high allelic frequency (0.50). Even in the absence of factor V Leiden, there were significant differences in the prevalence of activated protein C resistance and abnormal levels of sFlt1 between patients with preeclampsia homozygous for methylenetetrahydrofolate reductase C677T and controls (72 vs. 10%, p <0.008 and 63.6 vs. 10%, p < 0.05, respectively). Patients with two or more abnormal tests, including homozygousity for the C677T allele had an increased risk of preeclampsia than those with one or no abnormal test (OR: 3.15; CI: 1.1-9.02). CONCLUSION: Methylenetetrahydrofolate reductase C677T has a high allelic prevalence and is associated with markers of thrombosis and endothelial activation in Mexican women with preeclampsia.

Induction of apoptosis and effect on CD20+ using rituximab on autologous peripheral blood stem cell harvests from patients with B cell lymphomas.

Purging of neoplastic cells for autologous stem cell transplantation is usually done in vivo by administering chemotherapy and/or other agents before harvesting. It is also possible to decrease malignant cells counts directly in the cell harvest. In this study, we ascertained the effect of anti-CD20 monoclonal antibody and rituximab administration on peripheral blood hematopoietic stem cells. Five samples of stem cell harvests from different patients with B cell lymphoma were obtained. Each sample was divided in two tubes with calcium gluconate (20 mEq/50 microl). Rituximab (1 mg/600,000 mononuclear cells) was added to one of the tubes. Using flow cytometry, CD19, CD20 (B cell markers), and CD95 (apoptosis marker), expression was measured at baseline and 24 h after the addition of rituximab. A one-sided t-test with equal variances was used to analyze the results. Immediately after rituximab addition, CD20 expression became null. No significant difference in variation of CD19 expression was detected after the addition of rituximab (-3.64% control vs. 0.63% rituximab, p = 0.69). Mean variations of percentage of CD95 expression were 2.9% (controls) and 10.52% (rituximab tubes) (p = 0.06). We conclude that rituximab is capable of initiating apoptosis in vitro. We found no decrease in the CD19+ cell count, used as a surrogate marker for CD20+ cells, meaning that, at least in 24 h, apoptosis activation is not capable of decreasing CD20+ cell numbers. In vitro purging of peripheral blood stem cells harvests with rituximab could be part of a broader therapeutic strategy to be offered to lymphoproliferative disorder patients.

Metabolism of homocysteine and its relationship with cardiovascular disease.

Hyperhomocysteinemia, or the rise of plasmatic homocysteine levels above 15 mug/dL, is accepted nowadays as an independent risk factor for cardiovascular disease in men and women. Homocysteine (Hcy) is a non-protein forming aminoacid (aa) derivated from the loss of the methyl group, found within methionine. Methionine regenerates by retrieving the methyl radical from 5-methyltetrahydrofolate (5-MTHF) creating tetrahydrofolate (THF) which will then regenerate to 5-MTHF through the action of methylentetrahydrofolate reductase (MTHFR). This process is called remethylation. Alternatively, Hcy can follow the transsulfuration route, where through cystationine-beta-syntetase (CBS), it irreversibly converted into cystationine, a precursor of cysteine, glutathione, and other substances that are finally excreted in the urine. Hyperhomocysteinemia results from inhibition of the remethylation route, or inhibition or saturation of the transsulfuration pathway. Main factors causally associated increased plasmatic Hcy are mutations of the enzymes MTHFR and CBS; varying nutritional and health states; demographic factors; and, others. The most accepted hypotheses about Hcy action in cardiovascular disease are direct endothelial and vessel wall damage; oxidative stress generation; and, stimulation of a procoagulant and proinflammatory state of blood components. Since hyperhomocysteinemia can be effectively treated with folic acid, prospective trials are underway to determine if folate therapy is required to lower Hcy levels in plasma. These studies also attempt to address the impact, if any, of folate therapy in the reduction of cardiovascular risk, and to demonstrate if hyperhomocysteinemia is actually an independent risk factor that can be effectively treated.

Endothelin-1 and functional tissue factor: a possible relationship with severity in primary pulmonary hypertension.

Although dysfunctional endothelium, vasoconstriction, and in situ thrombosis are characteristics of primary pulmonary hypertension, the role that plasma vasomotor and coagulation factors play in this phenomenon are not completely understood. The aim of this work was to ascertain the diagnostic value of endothelin-1, thrombomodulin, tissue factor, and tissue factor pathway inhibitor, as well as their correlation with endothelial dysfunction in primary pulmonary hypertension patients. We analyzed the plasmatic concentration and chromogenic of the above-mentioned molecules using immunoenzymatic techniques. Patients were divided into responders and nonresponders on the basis of their hemodynamic response to a vasodilator trial. We found a continuous increase in endothelin-1 levels and a continuous decrease in functional tissue factor in the control group, responders, and nonresponders, respectively. Moreover, the patients showed a moderate decrease in thrombomodulin levels compared with the control group, without statistical significance. These results support a previous description of a decrease in thrombomodulin levels in primary pulmonary hypertension patients and suggests that an alteration of endothelin-1 and functional tissue factor could be related to a worsening of endothelial function and, indirectly, with the clinical severity of primary pulmonary hypertension.

Congenital thrombophilia associated to obstetric complications.

During pregnancy there are hemostatic changes that result in a hypercoagulable state and can have thrombotic consequences. This condition can be aggravated in women who are carriers of congenital thrombophilic factors. This thrombotic tendency can manifest as thrombotic lesions in the placenta with compromise of utero-placental circulation, which are common characteristics present in obstetric complications, such as preeclampsia/eclampsia, miscarriage, fetal loss, intrauterine growth retardation, and abruptio placentae. In this paper we review data concerning about the association of congenital thrombophilia in pregnancy with obstetric complications, mainly preeclampsia and fetal loss, focusing in factor V Leiden and its related activated protein C resistance, prothrombin mutation G20210A and hyperhomocysteinemia related with C677T mutation of methylenetetrahydrofolate reductase. Although factor V Leiden has been the thrombophilic factor most studied, all three thrombophilic mutations have been related with obstetric complications; however, contradictory results about the specific association of each mutation with each type of obstetric complication are described. These discrepancies could obey to the ethnic difference of the studied groups, or to the fact that some studies were performed in closed populations with few migratory movement, where the genetic pool is relatively homogeneous, as well as the different inclusion and exclusion criteria. Even though this variability is present, the significance of recognizing true associations between these thrombophilic mutations and obstetric complications is essential in order to determine the likelihood of routinely screening for these conditions in pregnant women with risk factors for thrombosis and for carrying out specific prophylactic measures.