Identification of genetic risk factors associated with ischaemic stroke in young Mexican patients.

BACKGROUND: Numerous polymorphisms in candidate genes coding for haemostatic system proteins have been proposed as risk factors for thrombosis. METHODS: We performed a case-control study of consecutive ischaemic stroke survivors aged ≤45 years, treated at our neurology department from 2006 to 2014. Polymerase chain reaction-restriction fragment length polymorphism identified the following polymorphisms: Thr325Ile and Ala147Thr in TAFI, 4G/5G in PAI-1, PLA1/A2 in platelet glycoprotein IIb/IIIa, Glu298Asp in eNOS, and C677T in 5,10-MTHFR. A multivariate logistic regression analysis was performed to evaluate the independent risk of stroke. RESULTS: 204 cases and 204 age- and sex-matched controls were included in the study. Clinical and genetic variables associated with ischaemic stroke were hypertension (P=.03), tobacco use (P=.02), and the polymorphisms Glu298Asp (genotype: P=.001, allele frequency: P=.001) and C677T (genotype: P=.01); the Ala147Thr, Thr325IIe, 4G/5G, and PLA1/A2 mutations were not associated with ischaemic stroke. The 298Asp (P=.03) and T (P=.01) alleles, hypertension (P=.03), tobacco use (P=.01) and family history of stroke (P=.04) were identified as independent risk factors. CONCLUSION: The polymorphisms Glu298Asp and C677T, affecting the eNOS and 5,10-MTHFR enzymes, respectively, and smoking, hypertension, and family history of stroke were associated with ischaemic stroke in young Mexican patients; this was not the case for the Thr325Ile, Ala147Thr, 4G/5G, and PLA1/A2 polymorphisms of the genes coding for fibrinolytic proteins and platelet receptors.

Identificación de factores de riesgo genéticos asociados a la enfermedad vascular cerebral de tipo isquémico en jóvenes mexicanos / Identification of genetic risk factors associated with ischaemic stroke in young Mexican patients

Introducción: Diversos polimorfismos en genes candidatos que codifican proteínas del sistema hemostático se han propuesto como factores de riesgo para el desarrollo de trombosis.MétodosCasos y controles, sobrevivientes de enfermedad vascular cerebral (EVC) isquémica idiopática ≤ 45 años de edad del servicio de neurología incluidos de manera consecutiva de 2006 a 2014. Por PCR-RFLP se identificaron los polimorfismos: Thr325Ile y Ala147Thr del gen de TAFI, 4G/5G del gen de PAI-1, PLA1/A2 del gen de la glucoproteína plaquetaria IIb/IIIa, Glu298Asp del gen de eNOS, y C677T del gen de la 5,10 MTHFR. Se realizó un análisis multivariado de regresión logística para calcular el riesgo independiente de EVC.ResultadosDoscientos cuatro casos y 204 controles pareados por edad y sexo. Se asoció al polimorfismo Glu298Asp (genotipo p = 0,001 y frecuencia alélica p = 0,001), C677T (genotipo p = 0,01), hipertensión (p = 0,03) y tabaquismo (p = 0,02) con la presencia de EVC isquémico, no así para los polimorfismos Ala147Thr, Thr325IIe, 4G/5G y PLA1/A2. Se identificó como factor de riesgo independiente al alelo 298Asp (p = 0,03), T (p = 0,01), hipertensión (p = 0,03), tabaquismo (p = 0,01) y AHFEAT (p = 0,04).ConclusionesLos polimorfismos Glu298Asp y C677T de los genes que codifican a la enzima eNOS y 5,10 MTHFR, tabaquismo, hipertensión y AHFEAT se asociaron a la presencia de EVC isquémico en jóvenes mexicanos, no así el Thr325Ile, Ala147Thr, 4G/5G, PLA1/A2 en genes que codifican proteínas del sistema de fibrinólisis y receptores plaquetarios. (AU)

Introduction: Numerous polymorphisms in candidate genes coding for haemostatic system proteins have been proposed as risk factors for thrombosis.MethodsWe performed a case-control study of consecutive ischaemic stroke survivors aged ≤ 45 years, treated at our neurology department from 2006 to 2014. Polymerase chain reaction–restriction fragment length polymorphism identified the following polymorphisms: Thr325Ile and Ala147Thr in TAFI, 4G/5G in PAI-1, PLA1/A2 in platelet glycoprotein IIb/IIIa, Glu298Asp in eNOS, and C677T in 5,10-MTHFR. A multivariate logistic regression analysis was performed to evaluate the independent risk of stroke.Results204 cases and 204 age- and sex-matched controls were included in the study. Clinical and genetic variables associated with ischaemic stroke were hypertension (P = .03), tobacco use (P = .02), and the polymorphisms Glu298Asp (genotype: P = .001, allele frequency: P = .001) and C677T (genotype: P = .01); the Ala147Thr, Thr325IIe, 4G/5G, and PLA1/A2 mutations were not associated with ischaemic stroke. The 298Asp (P = .03) and T (P = .01) alleles, hypertension (P = .03), tobacco use (P = .01) and family history of stroke (P = .04) were identified as independent risk factors.ConclusionsThe polymorphisms Glu298Asp and C677T, affecting the eNOS and 5,10-MTHFR enzymes, respectively, and smoking, hypertension, and family history of stroke were associated with ischaemic stroke in young Mexican patients; this was not the case for the Thr325Ile, Ala147Thr, 4G/5G, and PLA1/A2 polymorphisms of the genes coding for fibrinolytic proteins and platelet receptors. (AU)

von Willebrand's disease in Mexico: a pilot study.

von Willebrand's disease (VWD) is the most commonly inherited bleeding disorder. For a long time, it has been said that VWD was absent in some countries due to ethnical differences. Information about the prevalence of VWD in Mexico remains unclear, owing largely to poor awareness and diagnosis of the disease. The aim of this study was to objectively diagnose VWD in a cohort of highly selected Mexican patients with a chronic history of bleeding. Mexican Mestizos were recruited between July 2010 and August 2011. Included were 133 adult and paediatric patients with a high suspicion of VWD. Fifty-three were diagnosed with VWD: 47 (88.7%) with type 1 VWD, four (7.5%) with type 2a VWD and two (3.8%) with type 3 VWD. Mean age for female patients was 19.5 years (range 3-44 years) and 18.5 years (range 4-63 years) for male patients. Mean age at start of bleeding symptoms was 8.8 years (range 1-61). The most frequent clinical symptoms were epistaxis (84.9%), ecchymosis (79.2%), haematomas (71.7%), gum bleeds (62.3%) and petechia (50.9%). Severe transoperative or postoperative bleeding was found in 17 patients (32.1%). Twenty-six women at childbearing age had a history of abnormal gynaecological bleeding. Our results clearly demonstrate the presence of VWD in Mexican and underscore the importance of a more detailed description of VWD. Efforts to increase the awareness and diagnosis of VWD could help in better identification of patients with bleeding disorders and lead to early, appropriate management with safe and efficacious therapies such as desmopressin and plasma concentrates.

Anti-prolactin autoantibodies in pregnant women with systemic lupus erythematosus: maternal and fetal outcome.

The aim of this study was to determine in pregnant women with systemic lupus erythematosus (SLE) the frequency of anti-prolactin autoantibodies and to compare the outcome of pregnancy in SLE women with and without anti-prolactin autoantibodies. Ninety-nine consecutive SLE pregnant women and 151 healthy pregnant women were studied prospectively. Patients with or without anti-prolactin autoantibodies were identified by gel filtration chromatography and affinity chromatography for IgG. Serum total and free prolactin (PRL) levels and molecular heterogeneity of PRL at each trimester of pregnancy were determined. The frequency of anti-PRL autoantibodies in SLE pregnant women was 13.1%. Serum total PRL levels were significantly higher in women with anti-PRL autoantibodies compared with SLE women without anti-PRL autoantibodies and in healthy pregnant women; and serum free PRL levels were lower in the third trimester in women with anti-PRL autoantibodies than in healthy pregnant women. In contrast, serum total and free PRL levels were significantly lower in the second and third trimester in SLE pregnant women without anti-PRL autoantibodies compared with healthy pregnant women. All adverse outcomes of pregnancy studied were more frequent in SLE women without anti-PRL autoantibodies than anti-PRL autoantibody-positive SLE women. Moreover, both maternal and fetal main complications were significantly higher in SLE women without anti-PRL autoantibodies than anti-PRL autoantibody-positive SLE women (P

Interactions between bradykinin (BK) and cell adhesion molecule (CAM) expression in peptidoglycan-polysaccharide (PG-PS)-induced arthritis.

Bradykinin (BK), a vasoactive, proinflammatory nonapeptide, promotes cell adhesion molecule (CAM) expression, leukocyte sequestration, inter-endothelial gap formation, and protein extravasation in postcapillary venules. These effects are mediated by bradykinin-1 (B1R) and-2 (B2R) receptors. We delineated some of the mechanisms by which BK could influence chronic inflammation by altering CAM expression on leukocytes, endothelium, and synovium in joint sections of peptidoglycan-polysaccharide-injected Lewis rats. Blocking B1R results in significantly increased joint inflammation. Immunohistochemistry of the B1R antagonist group revealed increased leukocyte and synovial CD11b and CD54 expression and increased CD11b and CD44 endothelial expression. B2R antagonism decreased leukocyte and synovial CD44 and CD54 and endothelial CD11b expression. Although these findings implicate B2R involvement in the acute phase of inflammation by facilitating leukocyte activation (CD11b), homing (CD44), and transmigration (CD54). Treatment with a B2R antagonist did not affect the disease evolution in this model. In contrast, when both BK receptors are blocked, the aggravation of inflammation by B1R blockade is neutralized and there is no difference from the disease-untreated model. Our findings suggest that B1R and B2R signaling show physiologic antagonism. B1R signaling suggests involvement in down-regulation of leukocyte activation, transmigration, and homing. Further studies are needed to evaluate the B1 receptor agonist's role in this model.

Fine mapping of the sequences in domain 5 of high molecular weight kininogen (HK) interacting with heparin and zinc.

We previously localized the heparin binding region on high molecular weight kininogen to domain 5 (D5) by quantifying the binding using surface plasmon resonance of D5 fused at its N-terminal to glutathione-S-transferase. We further examined GST-(H475-S626) which at 100 nm was previously shown to be ineffective in reversing the heparin acceleration of antithrombin inhibition of thrombin. However, we now show that at a concentration of 400 nm, complete reversal of accelerated inhibition occurred. To characterize the interacting sequences on D5, four peptides representing surface loops of a molecular model were synthesized. Peptides H475-H485 and G440-G455, rich in histidine and low in lysine, showed weak or no detectable binding in the absence of Zn++, but tighter binding in the presence of Zn++. H483-K497 containing three histidines and six lysines showed tight binding without Zn++, and increased in avidity with Zn++. In contrast, G486-K502, low in histidine and high in lysine, showed tight binding (KD = 0.8 microm) in the absence and presence of Zn++. Both H483-K497 and G486-K502 were effective in neutralizing the accelerated inhibition by heparin of thrombin by antithrombin in the absence of Zn++. Therefore, a set of lysine residues in the sequence of K487-K502 is responsible for Zn++-independent binding of heparin. Further, a group of histidine residues in sequence range of H475-H485 contributes to Zn++-dependent binding of heparin to HK-D5.

Inhibition of angiogenesis by antibody blocking the action of proangiogenic high-molecular-weight kininogen.

Previously we demonstrated that domain 5 (D5) of high-molecular-weight kininogen (HK) inhibits neovascularization in the chicken chorioallantoic membrane (CAM) assay and further found that kallikrein cleaved HK (HKa) inhibited FGF2-and VEGF-induced neovascularization, and thus was antiangiogenic. In this study, we sought to demonstrate whether uncleaved HK stimulates neovascularization and thus is proangiogenic. The chick chorioallantoic membrane was used as an in ovo assay of angiogenesis. Low-molecular-weight kininogen stimulates angiogenesis, indicating that D5 is not involved. Bradykinin stimulates neovascularization equally to HK and LK and is likely to be responsible for the effect of HK. A murine monoclonal antibody to HK (C11C1) also recognizes a similar component in chicken plasma as detected by surface plasmon resonance. Angiogenesis induced by FGF2 and VEGF is inhibited by this monoclonal antibody and is a more potent inhibitor of neovascularization induced by VEGF than an integrin alphavbeta3 antibody (LM 609). Our postulate that C11C1 inhibits the stimulation of angiogenesis by HK was confirmed when either C11C1 or D5 completely inhibited angiogenesis in the CAM induced by HK. Growth of human fibrosarcoma (HT-1080) on the CAM was inhibited by GST-D5 and C11C1. These results indicate HK is proangiogenic probably by releasing bradykinin and that a monoclonal antibody directed to HK could serve as an antiangiogenic agent with a potential for inhibiting tumor angiogenesis and other angiogenesis-mediated disorders.

Regulation of leukocyte recruitment by polypeptides derived from high molecular weight kininogen.

Proteolytic cleavage of single-chain, high molecular weight kininogen (HK) by kallikrein releases the short-lived vasodilator bradykinin and leaves behind a two-chain, high molecular weight kininogen (HKa) reported to bind to the beta2-integrin Mac-1 (CR3, CD11b/CD18, alphaMbeta2) on neutrophils and exert antiadhesive properties by binding to the urokinase receptor (uPAR) and vitronectin. We define the molecular mechanisms for the antiadhesive effects of HK related to disruption of beta2-integrin-mediated cellular interactions in vitro and in vivo. In a purified system, HK and HKa inhibited the binding of soluble fibrinogen and ICAM-1 to immobilized Mac-1, but not the binding of ICAM-1 to immobilized LFA-1 (CD11a/CD18, alphaLbeta2). This inhibitory effect could be attributed to HK domain 5 and to a lesser degree to HK domain 3, consistent with the requirement of both domains for binding to Mac-1. Accordingly, HK, HKa, and domain 5 inhibited the adhesion of Mac-1 but not LFA-1-transfected K562 human erythroleukemic cells to ICAM-1. Moreover, adhesion of human monocytic cells to fibrinogen and to human endothelial cells was blocked by HK, HKa, and domain 5. By using peptides derived from HK domain 5, the sequences including amino acids H475-G497 (and to a lesser extent, G440-H455) were identified as responsible for the antiadhesive effect, which was independent of uPAR. Finally, administration of domain 5 into mice, followed by induction of thioglycollate-provoked peritonitis, decreased the recruitment of neutrophils by approximately 70% in this model of acute inflammation. Taken together, HKa (and particularly domain 5) specifically interacts with Mac-1 but not with LFA-1, thereby blocking Mac-1-dependent leukocyte adhesion to fibrinogen and endothelial cells in vitro and in vivo and serving as a novel endogenous regulator of leukocyte recruitment into the inflamed tissue.

Serum erythropoietin levels in kidney donors after renal transplantation.

BACKGROUND: Renal transplantation is the treatment of choice for many patients with end-stage renal disease. In the donor, renal excretory function is not affected after nephrectomy; however, little is known about other functions such as erythropoietin production. We studied the erythropoietin production in renal donors after nephrectomy. METHODS: We included healthy individuals fulfilling the criteria for kidney donation. Blood samples were collected before and monthly from 1 to 6 months after nephrectomy. Complete blood cell counts and erythropoietin were assayed. RESULTS: Eight kidney donors were studied. A significant increase in erythropoietin levels was observed during the first 3 months, but no difference was observed by the 4th month as compared with basal values. CONCLUSIONS: Erythropoietin production rose during the first 3 months after nephrectomy. However, erythropoietin was normal by the 4th month. Unchanged hemoglobin levels may suggest that the compensatory production of erythropoietin could participate in the preservation of an adequate physiological status of the donor after nephrectomy.