Factor XII Deficiency in Mexico: High Prevalence in the General Population and Patients with Venous Thromboembolic Disease.

INTRODUCTION: Thrombosis is one of the leading causes of morbidity and mortality worldwide. Venous thromboembolic disease (VTD) is considered a new epidemic. FXII deficiency is supposed to be a cause of thrombosis. To search for unknown causes of thrombosis in our population, our aim was to determine if FXII deficiency can be considered a risk factor for VTD. METHODS: Young adult Mexican patients with at least one VTD episode and healthy controls were included in this prospective, observational, controlled study. Liver and renal function tests, blood cytometry, and blood coagulation assays were performed. Plasma FXII activity and its concentration were evaluated. RESULTS: Over a two-year period, 250 patients and 250 controls were included. FXII activity was significantly lower in the control group compared to patients with VTD (p = 0.005). However, percentage of patients and controls with FXII deficiency was 8.8 and 9.2%, respectively (p = 1.000). No significant association was found between FXII deficiency and VTD (p = 1.0). FXII plasma concentration was lower in controls vs. patients with VTD: 4.05 vs. 6.19 ng/mL (p <0.001). Percentage of patients with low FXII plasma concentration was 1.6% and 6.0% in patients and controls, respectively (p = 0.010). CONCLUSIONS: FXII deficiency is a frequent finding in patients with VTD and controls in Mexico. Some patients with FXII deficiency had normal APTT result, an effect not described above. FXII plasma concentration was lower in patients with low activity.

Self-regulation of TNF-α Induces Dysfunction of Endothelial Colony-forming Cells from Patients with Venous Thromboembolic Disease.

BACKGROUND: Endothelial colony-forming cells (ECFCs) contribute to postnatal vasculogenesis. In venous thromboembolic disease (VTD), they are functionally abnormal and produce high concentrations of TNF-α. OBJECTIVE: To analyze the TNF-α signaling pathway and its relationship with the expression of cell-cycle regulators. METHODS: Mononuclear cells (MNCs) were collected from the peripheral blood of 20 healthy human volunteers (controls) and 30 patients with VTD matched by age (20-50 years) and sex to obtain ECFCs. We analyzed the relative quantification of the gene transcripts of TNF, NFkB1, PLAU, HMOX1, GSS, eNOS, CDKN1A, and CDKN1B through quantitative RT-PCR (qRT-PCR assays). Identification of NF-κB and activated targets of each pathway: NF-κB (Ser536); IκBα (Ser32/Ser36); p38 (Thr180/Tyr182) JNK (Thr183/Tyr185), p53 and cell-cycle regulators: p16, p18, p21, p27, p57, Cyclin D, Cyclin E, Cyclin A, Cyclin B, CDK2, CDK4; cell-cycle status was determined by KI-67 and 7-AAD. Cells were analyzed with flow cytometry and the FlowJo vX software. RESULTS: In ECFCs from VTD patients, TNF-α receptor and NFkB were overexpressed and hyper-phosphorylated; eNOS and HMOX1 were down-regulated; cell-cycle regulators (p53, p18, p21) were elevated. In addition, the cell cycle was locked in the G2 phase. CONCLUSIONS: Our results strongly suggest that these molecular alterations in the pathway of TNF-α and cell cycle regulation induce endothelial dysfunction, reduced proliferation potential and vascular regeneration, and consequently, the occurrence of new thrombotic events.

Enoxaparin augments alpha-1-antitrypsin inhibition of TMPRSS2, a promising drug combination against COVID-19.

The cell surface serine protease Transmembrane Protease 2 (TMPRSS2) is required to cleave the spike protein of SARS-CoV-2 for viral entry into cells. We determined whether negatively-charged heparin enhanced TMPRSS2 inhibition by alpha-1-antitrypsin (AAT). TMPRSS2 activity was determined in HEK293T cells overexpressing TMPRSS2. We quantified infection of primary human airway epithelial cells (hAEc) with human coronavirus 229E (HCoV-229E) by immunostaining for the nucleocapsid protein and by the plaque assay. Detailed molecular modeling was undertaken with the heparin-TMPRSS2-AAT ternary complex. Enoxaparin enhanced AAT inhibition of both TMPRSS2 activity and infection of hAEc with HCoV-229E. Underlying these findings, detailed molecular modeling revealed that: (i) the reactive center loop of AAT adopts an inhibitory-competent conformation compared with the crystal structure of TMPRSS2 bound to an exogenous (nafamostat) or endogenous (HAI-2) TMPRSS2 inhibitor and (ii) negatively-charged heparin bridges adjacent electropositive patches at the TMPRSS2-AAT interface, neutralizing otherwise repulsive forces. In conclusion, enoxaparin enhances AAT inhibition of both TMPRSS2 and coronavirus infection. Such host-directed therapy is less likely to be affected by SARS-CoV-2 mutations. Furthermore, given the known anti-inflammatory activities of both AAT and heparin, this form of treatment may target both the virus and the excessive inflammatory consequences of severe COVID-19.

Abo Blood Group, Atherothrombotic Comorbidities, and COVID-19: A Case-Control Study of their Association in the Mexican Population.

BACKGROUND: COVID-19 has been associated with negative results in patients with A blood group and with a better evolution in O blood group individuals. AIM: Because the evidence regarding ABO blood groups and COVID was empirically not that clear in our country, we tested the association regarding COVID-19 and blood groups. MATERIAL AND METHODS: Adult patients were enrolled in this prospective, case-control, observational multicenter study. Patients with a confirmed diagnosis of COVID-19 were assigned to one of three groups based on the clinical presentation of the infection. Age, gender, ABO and Rh blood groups, body mass index, history of diabetes mellitus or high blood pressure, and smoking were recorded directly or from their clinical charts. ABO blood group was obtained from 5,000 blood donors (50% each gender). Atherothrombotic variables were compared with a nation-wide data collection. RESULTS: A total of 2,416 patients with COVID-19 were included (women:39.6%; men:60.4%). There were no significant differences between cases and controls in terms of age. O blood group was the most frequently found in healthy donors and COVID-19 patients, but this blood group was significantly higher in COVID-19 patients vs. healthy donors. ABO blood group was not associated with the final health status in COVID-19 patients. Obesity, diabetes mellitus, hypertension and smoking were significantly more frequent among COVID-19 patients. CONCLUSION: The proposed protective effect of the O blood group in COVID-19 patients could not be reproduced in the Mexican population while some atherothrombotic risk factors had a significant effect on the clinical evolution.

Consenso mexicano para el diagnóstico y tratamiento de la trombastenia de Glanzmann / Mexican consensus on the diagnosis and treatment of Glanzmann thrombasthenia

Resumen Las plaquetas tienen un papel central en diferentes escenarios fisiológicos, incluyendo la hemostasia; se unen unas con otras en la agregación plaquetaria, lo cual permite formar un coágulo plaquetario. Para que la agregación sea apropiada se requiere del complejo glicoproteico IIb/IIIa (GPIIb/IIIa) en la superficie plaquetaria. Toda alteración funcional plaquetaria, hereditaria o adquirida, impide la formación adecuada del coágulo y se manifiesta como hemorragia. Las enfermedades plaquetarias hereditarias son raras y, hasta recientemente, fueron ignoradas. Una de las más reconocidas y estudiadas es la trombastenia de Glanzmann (TG), entidad en la cual el número de plaquetas puede ser normal pero la función está alterada. Es un padecimiento autosómico y recesivo que causa hemorragia de diferente intensidad toda la vida y en la cual el problema radica en precisamente en la GPIIb/IIIa. Las hemorragias son típicamente mucocutáneas: equimosis, púrpura, epistaxis, gingivorragia; menos frecuentes son la hemorragia gastrointestinal, hemartrosis o en sistema nervioso central. La hiperpolimenorrea es común en las mujeres y llega a ser tan importante que amerita transfusiones en la menarca. La TG afecta a todos los grupos étnicos y su prevalencia varía entre 1/40,000 y 1/400,000. A pesar de esta información acerca de la TG en el mundo, hay pocas guías o recomendaciones basadas en la opinión de expertos y experiencias unicéntricas. En México la TG es rara y no se cuenta con una recomendación general para su diagnóstico y tratamiento. El objetivo de este documento fue establecer un consenso y hacer sugerencias generales para su diagnóstico y tratamiento.

Abstract Platelets have a central role in several physiological scenarios including hemostasis. Platelets bind each other during platelet aggregation allowing the proper formation of the clot; to be appropriate, platelet aggregation requires the glycoproteic complex IIb/IIIa (GPIIb/IIIa). Every platelet function abnormality both, congenital or acquired, impedes clot formation and favors bleeding episodes. Hereditary platelet abnormalities are rare and, until recently, they were almost ignored. Among these disorders, Glanzmann Thrombasthenia (GT) is a widely recognized abnormality in which platelet counts may be normal, but their function is affected. GT is an autosomal, recessive disease that causes life-long bleeding of different intensity. Main biochemical abnormality resides in GPIIb/IIIa. Bleeding is typically mucocutaneous: easy bruising, purpura, and nose and gum bleeds; less frequently are gastrointestinal bleeds, hemarthrosis, or intracranial. Menorrhagia and hyperpolymenorrhea are common findings in in women and may be the cause of anemia requiring blood transfusions at fertile age. GT affects all ethnic groups and its prevalence ranges between 1/40,000 to 1/400,000. Despite this worldwide information regarding GT, only a few guidelines and recommendations have been published, most of them based on expert opinions. In Mexico, GT is rare and there is not a general recommendation regarding its diagnosis and treatment. The aim of this document was to establish a consensus to suggest a general guideline for the diagnosis and treatment of GT in Mexico.

Mechanisms of Immunothrombosis by SARS-CoV-2.

SARS-CoV-2 contains certain molecules that are related to the presence of immunothrombosis. Here, we review the pathogen and damage-associated molecular patterns. We also study the imbalance of different molecules participating in immunothrombosis, such as tissue factor, factors of the contact system, histones, and the role of cells, such as endothelial cells, platelets, and neutrophil extracellular traps. Regarding the pathogenetic mechanism, we discuss clinical trials, case-control studies, comparative and translational studies, and observational studies of regulatory or inhibitory molecules, more specifically, extracellular DNA and RNA, histones, sensors for RNA and DNA, as well as heparin and heparinoids. Overall, it appears that a network of cells and molecules identified in this axis is simultaneously but differentially affecting patients at different stages of COVID-19, and this is characterized by endothelial damage, microthrombosis, and inflammation.

Analysis of the quality of anticoagulation with vitamin K antagonists in three clinical scenarios in Mexico.

INTRODUCTION: Vitamin K antagonists (VKA) are a therapeutic alternative in patients with venous thromboembolic disease; however, numerous factors affect their pharmacology. OBJECTIVE: To evaluate the quality of VKA anticoagulation at three different time periods in Mexico. METHODS: Prospective study, nested in patient cohorts at three different clinical scenarios between 2013 and 2019. Outpatients with indication for treatment with VKAs for at least 12 months were included. Patients were managed according to the criteria of the treating physician. RESULTS: Patient general characteristics were similar between groups, except for the VKA indication. The results of 4,148 patients and 38,548 INR assessments were analyzed. The times in therapeutic range during the three phases of the study and pooled data were significantly higher for the anticoagulation clinic. Only the number of patient visits was significantly associated with the results, unlike age, gender, and type of VKA. CONCLUSIONS: VKAs are widely used, but it is difficult for therapeutic goals to be achieved, especially in non-specialized clinical services. Creation of anticoagulation clinics is an urgent need for the Mexican health system.

INTRODUCCIÓN: Los antagonista de la vitamina K (AVK) son una alternativa terapéutica en los pacientes con enfermedad tromboembólica venosa; sin embargo, numerosos factores afectan su farmacología. OBJETIVO: Evaluar la calidad de la anticoagulación AVK durante tres diferentes periodos en México. MÉTODOS: Estudio prospectivo, anidado en cohortes de pacientes en tres escenarios clínicos entre los años 2013-2019. Se incluyeron pacientes no hospitalizados con indicación para recibir AVK por al menos 12 meses, quienes fueron manejados de acuerdo con el criterio del médico tratante. RESULTADOS: Las características generales de los pacientes fueron similares entre los grupos, excepto por la indicación para usar los AVK. Se analizaron los resultados de 4148 pacientes y 38 548 evaluaciones de INR. Los tiempos en rango terapéutico durante las tres fases del estudio y los datos acumulados fueron significativamente mayores en la clínica de anticoagulación. Solo el número de visitas de control de los pacientes se asoció significativamente con los resultados, a diferencia de la edad, el sexo y el tipo de AVK. CONCLUSIONES: Los AVK se utilizan ampliamente, pero es difícil alcanzar la meta terapéutica, sobre todo en servicios clínicos no especializados. La creación de clínicas de anticoagulación es una necesidad urgente en el sistema mexicano de salud.

A proposal for the management of COVID-19-induced coagulopathy in adults.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is the cause of the coronavirus disease 2019 (COVID-19) pandemic, which has a high case fatality rate. Most severely ill patients develop a special type of coagulopathy that had not been described before and that is now considered the main cause of death. For this reason, anticoagulant treatment has become one of the cornerstones of the treatment of this infection. However, the rate at which the evidence regarding the use of anticoagulants is generated is quite fast, and sometimes it is difficult to interpret and conflicting. After having performed an extensive review of the published literature, this proposal for the use of anticoagulant treatment is made, taking into account available resources in Mexico.

La infección por coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2) es la causante de la pandemia de enfermedad por coronavirus 2019 (COVID-19), con un índice de letalidad alto. La mayoría de los pacientes graves desarrollan un tipo especial de coagulopatía no descrito hasta ahora y la cual se considera ahora la principal causa de muerte. Por esta razón, el tratamiento anticoagulante se ha convertido en una de las piedras angulares del tratamiento de esta infección. Sin embargo, la velocidad con la que se genera la evidencia respecto al uso de anticoagulantes es muy rápida y, en ocasiones difícil de interpretar y contradictoria. Luego de hacer una revisión extensa de la literatura publicada, se hace esta propuesta para el uso del tratamiento anticoagulante tomando en cuenta los recursos disponibles en México.

Análisis de la calidad de la anticoagulación con antagonistas de la vitamina K en tres escenarios clínicos en México / Analysis of the quality of anticoagulation with vitamin K antagonists in three clinical scenarios in Mexico

Resumen Introducción: Los antagonista de la vitamina K (AVK) son una alternativa terapéutica en los pacientes con enfermedad tromboembólica venosa; sin embargo, numerosos factores afectan su farmacología. Objetivo: Evaluar la calidad de la anticoagulación AVK durante tres diferentes periodos en México. Métodos: Estudio prospectivo, anidado en cohortes de pacientes en tres escenarios clínicos entre los años 2013-2019. Se incluyeron pacientes no hospitalizados con indicación para recibir AVK por al menos 12 meses, quienes fueron manejados de acuerdo con el criterio del médico tratante. Resultados: Las características generales de los pacientes fueron similares entre los grupos, excepto por la indicación para usar los AVK. Se analizaron los resultados de 4148 pacientes y 38 548 evaluaciones de INR. Los tiempos en rango terapéutico durante las tres fases del estudio y los datos acumulados fueron significativamente mayores en la clínica de anticoagulación. Solo el número de visitas de control de los pacientes se asoció significativamente con los resultados, a diferencia de la edad, el sexo y el tipo de AVK. Conclusiones: Los AVK se utilizan ampliamente, pero es difícil alcanzar la meta terapéutica, sobre todo en servicios clínicos no especializados. La creación de clínicas de anticoagulación es una necesidad urgente en el sistema mexicano de salud.

Abstract Introduction: Vitamin K antagonists (VKA) are a therapeutic alternative in patients with venous thromboembolic disease; however, numerous factors affect their pharmacology. Objective: To evaluate the quality of VKA anticoagulation at three different time periods in Mexico. Methods: Prospective study, nested in patient cohorts at three different clinical scenarios between 2013 and 2019. Outpatients with indication for treatment with VKAs for at least 12 months were included. Patients were managed according to the criteria of the treating physician. Results: Patient general characteristics were similar between groups, except for the VKA indication. The results of 4,148 patients and 38,548 INR assessments were analyzed. The times in therapeutic range during the three phases of the study and pooled data were significantly higher for the anticoagulation clinic. Only the number of patient visits was significantly associated with the results, unlike age, gender, and type of VKA. Conclusions: VKAs are widely used, but it is difficult for therapeutic goals to be achieved, especially in non-specialized clinical services. Creation of anticoagulation clinics is an urgent need for the Mexican health system.

Propuesta para manejo de la coagulopatía asociada a la COVID-19 en adultos / A proposal for the management of COVID-19-induced coagulopathy in adults

Resumen La infección por coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2) es la causante de la pandemia de enfermedad por coronavirus 2019 (COVID-19), con un índice de letalidad alto. La mayoría de los pacientes graves desarrollan un tipo especial de coagulopatía no descrito hasta ahora y la cual se considera ahora la principal causa de muerte. Por esta razón, el tratamiento anticoagulante se ha convertido en una de las piedras angulares del tratamiento de esta infección. Sin embargo, la velocidad con la que se genera la evidencia respecto al uso de anticoagulantes es muy rápida y, en ocasiones difícil de interpretar y contradictoria. Luego de hacer una revisión extensa de la literatura publicada, se hace esta propuesta para el uso del tratamiento anticoagulante tomando en cuenta los recursos disponibles en México.

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is the cause of the coronavirus disease 2019 (COVID-19) pandemic, which has a high case fatality rate. Most severely ill patients develop a special type of coagulopathy that had not been described before and that is now considered the main cause of death. For this reason, anticoagulant treatment has become one of the cornerstones of the treatment of this infection. However, the rate at which the evidence regarding the use of anticoagulants is generated is quite fast, and sometimes it is difficult to interpret and conflicting. After having performed an extensive review of the published literature, this proposal for the use of anticoagulant treatment is made, taking into account available resources in Mexico.

The influence of hydrogen ions on coagulation in traumatic brain injury, explored by molecular dynamics.

Background: Patients in intensive care units with traumatic brain injuries (TBI) frequently present acid-base abnormalities and coagulability disorders, which complicate their condition.Objective: To identify protonation through in silico simulations of molecules involved in the process of coagulation in standard laboratory tests.Materials and methods: Ten patients with TBI were selected from the intensive care unit in addition to ten "healthy control subjects", and another nine patients as "disease control subjects"; the latter being a comparative group, corresponding to subjects with diabetes mellitus 2 (DM2). Fibrinogen, FVII, FVIII, FIX, FX, and D-dimer in the presence of acidification were evaluated in 20 healthy subjects in order to compare clinical results with molecular dynamics (MD), and to explain proton interactions and coagulation molecules.Results: The TBI group presented a slight, non-significant increase in D-dimer; but this was not present in "disease control subjects". Levels of fibrinogen, FVII, FIX, FX, and D-dimer were affected in the presence of acidification. We observed that various specific residues of coagulation factors "trap" ions.Conclusion: Protonation of tissue factor and factor VIIa may favor anticoagulant mechanisms, and protonation does not affect ligand binding sites of GPIIb/IIIa (PAC1) suggesting other causes for the low affinity to PAC1.

Clinical relevance of NKT cells and soluble MIC-A in Hodgkin lymphoma.

Previous studies demonstrated that the majority of Hodgkin lymphoma (HL) patients achieve response after treatment, while 5% become refractory. Studies analyzing the role of lymphocyte subsets in peripheral blood are limited. This investigation sought to evaluate peripheral blood lymphocyte subsets and soluble MHC class I chain-related proteins A and B (sMIC-A/B) and their correlation with survival in patients with newly diagnosed HL. The study recruited 36 patients and 72 healthy donors. HL patients showed a decrease in CD4, B, monocytes, NK, and NKT cells; and an increase in γ-δ T cells and soluble MIC-A serum levels. Higher values of s-MIC-A  >100 ng/mL and NKT cells >40 µL correlated with poor overall survival (OS). In conclusion, in HL peripheral blood CD4 T and B cells, monocytes, NK, and NKT cells were decreased, while s-MIC-A and γ-δ T cells increased. Higher values of s-MIC-A and NKT cells correlated with poor survival.

Important decrease in invariant natural killer T, CD4+ regulatory T cells, CD8+ regulatory T cells, gamma-delta T cells, and CD4+ T lymphocytes in HIV-negative patients with hemophilia.

Hereditary hemophilias are X-linked inherited bleeding disorders defined as deficiencies of the coagulation factors VIII or IX. They are characterized by easy to provoke or spontaneous bleeding. HIV infection in hemophilic patients is a risk factor for the reduction of CD4+ T cells. There is no information regarding the cellular immune function in HIV-negative patients with hemophilia. To evaluate the number of lymphocyte subsets in adult patients with hemophilia A or B as compared with healthy donors. 39 Adult hemophilics and 27 healthy donors were included. Lymphocyte subsets [CD4 and CD8 T cells, natural killer cells, natural killer T (NKT) cells, invariant NKT (iNKT) cells, gamma-delta T (γδT) cells, type 1 and 2 dendritic cells, CD14 monocytes, CD4 and CD8 regulatory T cells (Tregs), and B cells], were analyzed by flow cytometry. A significant decrease of CD4+ T lymphocytes, γδT cells, iNKT cells, CD4+ and CD8+ Tregs was observed in patients with hemophilia. Those patients having factor VIII inhibitor had the lowest CD4+ Treg and CD8+ Treg counts. CD14 monocytes were increased, as well as iNKT and type 2 dendritic cells in obese-overweight hemophilics. CD4+ lymphocytes, iNKT, γδT cells, and Tregs (CD4+ and CD8+), are significantly decreased in patients with hemophilia. Depletion of Tregs is more important in patients with factor VIII inhibitor. Physicians caring for hemophilia patients should realize that, even when they are not suffering infections frequently, may have early evidence of cellular immunodeficiency.

FLT3-ITD and CD135 Over-Expression are Frequent Findings of Poor Survival in Adult Patients with Acute Leukemias.

BACKGROUND: Fms-like tyrosine kinase 3 (FLT3) expression and mutation have been considered a poor prognostic factor in acute myeloid leukemia (AML). FLT3-ITD mutation is present in 30% of adult patients with AML and 2-5% in childhood acute lymphoblastic leukemia (ALL). The impact of these mutations on the prognosis of ALL patients, has not yet been established. Moreover, a limited number of publications regarding the level of expression of the FLT3 receptor (CD135) in both leukemias exist. This study aimed to analyze the clinical outcomes associated to the presence of FLT3-ITD mutation and the expression of CD135. METHODS: 82 adult patients with newly diagnosed acute leukemia (39 with AML and 43 with ALL) were included. Flow cytometry and RT-PCR were done to analyze the expression of CD135 and the presence of FLT3 ITD mutation, respectively. RESULTS: FLT3-ITD was present in 14 (36%) of AML and 15 (35%) of ALL patients. Disease free survival (DFS) and overall survival (OS) were lower in ALL patients having a CD135 expression >3000 cells/µL. There was a trend for poor OS in AML patients expressing FLT3 ITD. OS was worse in AML patients with high expression of CD135. CONCLUSION: A higher (35%) frequency of FLT3-ITD was found in adult ALL patients. The presence of FLT3-ITD was associated with a trend of poor OS in AML cases, and overexpression of CD135 was correlated with poor DFS in ALL cases and poor OS in both acute leukemias.

Cystathionine ß-synthase and methylenetetrahydrofolate reductase mutations in Mexican individuals with hyperhomocysteinemia.

BACKGROUND: Hyperhomocysteinemia, a thrombotic risk factor, may have several causes. Among the genetic causes of hyperhomocysteinemia, there are polymorphisms in the enzymes methylenetetrahydrofolate reductase (C677T) and cystathionine ß-synthase (C699T, C1080T, and 844ins68). Although the frequency of hyperhomocysteinemia in our country is high, there is no evidence about the frequencies of these polymorphisms. METHODS: We analyzed 80 healthy individuals from several regions in our country. We evaluated the fasting and post-oral methionine load plasma Hcy and the genotypes in order to obtain the allele frequencies of the polymorphisms C677T of methylenetetrahydrofolate reductase and C699T, C1080T, and 844ins68 of the cystathionine ß-synthase. RESULTS: No individual had deficiency of folic acid, vitamins B12, or B6, but 80% had post-oral methionine load hyperhomocysteinemia. We found a significant increase in the Hcy plasma concentration associated with age and gender. Only the polymorphism C1080T was significantly associated with hyperhomocysteinemia. CONCLUSION: There is an association between fasting and post-oral methionine load plasma Hcy concentrations with the allelic frequencies of the polymorphisms C669T, 844ins68, and C1080T of the cystathionine ß-synthase and C667T of the methylenetetrahydrofolate reductase in healthy Mexican individuals. As compared with individuals with normal fasting or post-oral methionine load Hcy plasma levels, only C1080T was significantly associated with hyperhomocysteinemia.

Proposal for the management of COVID-19-associated coagulopathy in children.

SARS-CoV-2 infection (COVID-19) has become a pandemic with a high case fatality rate that mainly affects adults. Most severely ill adult patients develop a coagulopathy that was not described until recently, and which is currently considered a main cause of death. Everything indicates that a similar phenomenon also occurs in children with COVID-19. Anticoagulant treatment has become one of the therapeutic foundations for this infection; however, its implementation in children can be difficult since, until recently, it was not considered in the pediatric population. Evidence regarding the use of anticoagulants in COVID-19 is rapidly generated, changes constantly, it is often difficult to interpret, and can be contradictory. After an extensive review of the published literature, a proposal was generated that offers suggestions for anticoagulant treatment, considering available resources in Mexico.

La infección por SARS-CoV-2 (COVID-19) se ha constituido en una pandemia con alto índice de letalidad que afecta principalmente a los adultos. La mayor parte de los pacientes adultos graves desarrolla una coagulopatía que no estaba descrita, la cual actualmente se considera la principal causa de muerte. Todo indica que un fenómeno parecido ocurre también en el niño con COVID-19. El tratamiento anticoagulante se ha convertido en uno de los fundamentos terapéuticos de esta infección; sin embargo, su establecimiento en el niño puede ser difícil ya que, hasta hace poco, no estaba considerado en la población pediátrica. La evidencia respecto al uso de anticoagulantes en COVID-19 se genera con rapidez, cambia constantemente, con frecuencia es difícil de interpretar y puede ser contradictoria. Después de una extensa revisión de la literatura publicada, se generó una propuesta que ofrece sugerencias para el tratamiento anticoagulante en la que se consideran los recursos disponibles en México.