Hyperhomocysteinemia and Risk of First Venous Thrombosis: The Influence of (Unmeasured) Confounding Factors

Hereditary thrombophilia as a possible risk factor for severe disease in COVID-19: a case series

PURPOSE

The risk factors that modulate one's susceptibility for severe COVID-19 have been well documented. Despite this, hypercoagulability remains an often overlooked risk factor for severe disease for COVID-19. Because COVID-19 infection is a risk factor for hypercoagulability, a reasonable presumption/hypothesis is that patients with hereditary thrombophilia would be at a higher risk of thrombotic complications associated with COVID-19 infection.

METHODS

This case report details two cases where previously unknown hereditary thrombophilias likely contributed to the mortality of COVID-19 patients.

RESULTS

The first COVID-19 patient's cause of death was pulmonary thromboemboli from deep vein thrombosis due to heterozygous MTHFR C667T and heterozygous PAI-1 4G/5G mutations. The second COVID-19 patient's cause of death was an acute myocardial infarct due to a coronary artery thrombosis in the setting of heterozygous MTHFR A1298C and homozygous PAI-1 4G/5G mutations. In each case, COVID-19 infection was also considered contributory to death.

CONCLUSION

The occurrence of these fatal thrombotic events in COVID-19 patients with hereditary thrombophilias raises questions as to whether this combination of thrombotic risk factors for hypercoagulability may have placed patients at a significant enough risk to experience these fatal thrombotic complications. Thus, while not sufficient alone to prove that SARS-CoV-2 patients with hereditary thrombophilias are at increased risk for thrombotic complications, these two cases indicate that further investigation is warranted into elucidating the relationship between thrombotic risk factors as it may identify an additional high-risk medical condition for COVID-19 and have important diagnostic and therapeutic ramifications.

Vitamin B12 Metabolism: A Network of Multi-Protein Mediated Processes

The water-soluble vitamin, vitamin B12, also known as cobalamin, plays a crucial role in cellular metabolism, particularly in DNA synthesis, methylation, and mitochondrial functionality. Its deficiency can lead to hematological and neurological disorders; however, the manifestation of these clinical outcomes is relatively late. It leads to difficulties in the early diagnosis of vitamin B12 deficiency. A prolonged lack of vitamin B12 may have severe consequences including increased morbidity to neurological and cardiovascular diseases. Beyond inadequate dietary intake, vitamin B12 deficiency might be caused by insufficient bioavailability, blood transport disruptions, or impaired cellular uptake and metabolism. Despite nearly 70 years of knowledge since the isolation and characterization of this vitamin, there are still gaps in understanding its metabolic pathways. Thus, this review aims to compile current knowledge about the crucial proteins necessary to efficiently accumulate and process vitamin B12 in humans, presenting these systems as a multi-protein network. The epidemiological consequences, diagnosis, and treatment of vitamin B12 deficiency are also highlighted. We also discuss clinical warnings of vitamin B12 deficiency based on the ongoing test of specific moonlighting proteins engaged in vitamin B12 metabolic pathways.

Hyperhomocysteinemia is associated with the risk of venous thromboembolism in patients with mental illness: a case-control study

Objective

The risk of venous thromboembolism in patients with mental illness has been insufficiently addressed. This study aimed to assess the correlation between hyperhomocysteinemia and venous thromboembolism prevalence among this population.

Methods

Patients with a diagnosis of mental illness and concurrent venous thromboembolism, admitted to Sir Run Run Shaw Hospital at Zhejiang University School of Medicine between January 2014 and December 2021, were included in the venous thromboembolism group. The control group, approximately twice the size, comprised individuals with mental illness but without venous thromboembolism. Basic clinical data were gathered for both cohorts.

Results

In psychiatric patients, elevated D-dimer levels(OR=5.60,95% CI 3.28-10.00), hyperhomocysteinemia (OR=2.37,95% CI 1.10-5.14), and hyperprolactinemia(OR= 2.68,95% CI 1.12-6.42)were significant risk factors for venous thromboembolism. According to further subgroup analyses, hyperhomocysteinemia is a significant risk factor associated with pulmonary embolism, with an OR of 5.08 (95% CI 1.20-21.48). An interaction effect between gender and homocysteine level was found, with a p-interaction of 0.022. A subsequent analysis confirmed the association between hyperhomocysteinemia and venous thromboembolism in female psychiatric patients, with an OR of 3.34 (95% CI 1.68-6.65), indicating that hyperhomocysteinemia is a significant risk factor for venous thromboembolism in women.

Conclusion

Patients with psychiatric disorders were found to have an elevated risk of venous thromboembolism, which was associated with increased levels of D-dimer, hyperprolactinemia, and hyperhomocysteinemia. A strong correlation between hyperhomocysteinemia and pulmonary embolism was identified in patients with mental illnesses. Furthermore, the study revealed that female psychiatric patients with hyperhomocysteinemia constituted a high-risk group for venous thromboembolism. This finding holds significant clinical implications, suggesting that early preventative measures could be implemented for this high-risk population to reduce the incidence of thromboembolic events during hospitalization for psychiatric patients.

A Comprehensive Review of Risk Factors and Thrombophilia Evaluation in Venous Thromboembolism

Venous thromboembolism (VTE), which encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE), is a significant cause of morbidity and mortality worldwide. There are many factors, both acquired and inherited, known to increase the risk of VTE. Most of these result in increased risk via several common mechanisms including circulatory stasis, endothelial damage, or increased hypercoagulability. Overall, a risk factor can be identified in the majority of patients with VTE; however, not all risk factors carry the same predictive value. It is important for clinicians to understand the potency of each individual risk factor when managing patients who have a VTE or are at risk of developing VTE. With this, many providers consider performing a thrombophilia evaluation to further define a patient's risk. However, guidance on who to test and when to test is controversial and not always clear. This comprehensive review attempts to address these aspects/concerns by providing an overview of the multifaceted risk factors associated with VTE as well as examining the role of performing a thrombophilia evaluation, including the indications and timing of performing such an evaluation.

The dos, don'ts, and nuances of thrombophilia testing

Considerable progress has been made in elucidating genetic and biologic risk factors for venous thromboembolism (VTE). Despite being able to identify heritable defects in a substantial proportion of patients with VTE, testing has not, in general, proven useful in management. Despite efforts to reduce inappropriate testing, it often falls to the hematologist to consult on patients having undergone thrombophilia testing. Through a series of cases, we discuss how D-dimer testing can be helpful in VTE recurrence risk stratification in younger women as well as how to approach patients with persistently elevated D-dimer levels in the absence of thrombosis. While elevated factor VIII coagulant activity levels are a significant risk factor for a first episode of VTE, its biologic basis is not fully understood, and studies have not shown it to be a useful predictor of recurrence. Abnormal results of genetic tests for methylene tetrahydrofolate reductase or plasminogen activator 1 promoter polymorphisms may be encountered, which carry little if any thrombotic risk and should never be ordered. We also discuss protein S deficiency, the most difficult of the hereditary thrombophilias to diagnose due to a wider "normal" range in the general population as compared with protein C, the presence of both free and bound forms in plasma, and the characteristics of the various assays in use. We also present a rare type of protein C deficiency that can be missed by functional assays using an amidolytic rather than a clotting end point.

Non-Conventional Risk Factors: "Fact" or "Fake" in Cardiovascular Disease Prevention?

Cardiovascular diseases (CVDs), such as arterial hypertension, myocardial infarction, stroke, heart failure, atrial fibrillation, etc., still represent the main cause of morbidity and mortality worldwide. They significantly modify the patients' quality of life with a tremendous economic impact. It is well established that cardiovascular risk factors increase the probability of fatal and non-fatal cardiac events. These risk factors are classified into modifiable (smoking, arterial hypertension, hypercholesterolemia, low HDL cholesterol, diabetes, excessive alcohol consumption, high-fat and high-calorie diet, reduced physical activity) and non-modifiable (sex, age, family history, of previous cardiovascular disease). Hence, CVD prevention is based on early identification and management of modifiable risk factors whose impact on the CV outcome is now performed by the use of CV risk assessment models, such as the Framingham Risk Score, Pooled Cohort Equations, or the SCORE2. However, in recent years, emerging, non-traditional factors (metabolic and non-metabolic) seem to significantly affect this assessment. In this article, we aim at defining these emerging factors and describe the potential mechanisms by which they might contribute to the development of CVD.

Nitrous oxide-induced polyneuropathy, pancytopenia and pulmonary embolism: a case report

BACKGROUND

Nitrous oxide is a medical and household gas that has seen its use drift to recreational purpose among the young population in recent years. Significant neurological, hematological and psychiatric side effects, generally related to an induced functional vitamin B12 deficiency, have been described separately in the literature.

CASE REPORT

A 22-year-old woman of North African origin experienced an exceptional combination of polyneuropathy, bilateral pulmonary embolism and severe pancytopenia related to vitamin B12 deficiency and hyperhomocysteinemia induced by recreational nitrous oxide use. After treatment with vitamin B12 supplementation and intensive rehabilitative management, the patient progressively regained the ability to walk and her biological parameters gradually returned to normal. The pathophysiological mechanisms related to a decrease in vitamin B12 activity are the reduction of products needed for synthesis of deoxyribonucleic acid, carbohydrate or fatty acids, and the increase of hyperhomocysteinemia. Other mechanisms involving a direct action of N2O are also suspected.

CONCLUSION

This case report brings elements to support our knowledge about pathological pathway, recovery and prognosis of recreational N2O abuse complications. The general and medical population should be aware to the serious consequences of this type of consumption.

Retinal Vein Occlusion after COVID-19 Vaccination-A Review

Background Retinal vein occlusion (RVO) occurring after COVID-19 vaccination has been reported worldwide. Such a sight-threatening condition occurring after COVID-19 vaccination is a menace to ophthalmic health. This article reviews current evidence related to post-COVID-19 vaccination RVO. Method A total of 29 relevant articles identified on PubMed in January 2023 were selected for review. Observation All cases presented to ophthalmologists with visual loss shortly after COVID-19 vaccination. Mean and median age were both 58. No sex predominance was observed. RVO was diagnosed from findings on dilated fundal examination and ophthalmic imaging. AstraZeneca and BNT vaccines accounted for most cases. Vascular risk factors, e.g., diabetes mellitus and hypertension, were common. Most laboratory tests requested came back unremarkable. Most patients responded well to standard treatment, except those with ophthalmic comorbidities. Visual prognosis was excellent on short-term follow-up. Discussion The causality between RVO and COVID-19 vaccination is undeterminable because of the nature of articles, heterogenous reporting styles, contradicting laboratory findings and co-existing vascular risk factors. Vaccine-induced immune thrombotic thrombocytopenia, retinal vasculitis and homocysteinaemia were proposed to explain post-vaccination RVO. Large-scale studies have demonstrated that the incidence of RVO following COVID vaccination is very low. Nevertheless, the effects of boosters on retinal vasculature and ophthalmic health are still unclear. Conclusions The benefits of COVID-19 vaccination are believed to outweigh its ophthalmic risks. To ensure safe vaccination, the prior optimisation of comorbidities and post-vaccination monitoring are important. COVID-19 vaccines (including boosters) should be offered with reasonable confidence. Further studies are warranted to elucidate the ophthalmic impact of vaccines.

Nitrous Oxide-Induced Cerebral Venous Thrombosis: A Case Report, Potential Mechanisms, and Literature Review

Cerebral venous thrombosis can result from hypercoagulation, either genetic or acquired. Hyperhomocysteninemia was previously thought to be linked with thrombophilia, although this is still controversial to this present day. In recent years, there has been a notable surge in the recreational use of nitrous oxide, which could potentially lead to hyperhomocysteinemia. We present a case of a 19-year-old female who was diagnosed with cerebral venous thrombosis with intracerebral hemorrhage. She had a history of nitrous oxide abuse, which is known to cause dysfunction of vitamin B12. Additionally, we conducted a literature review of cerebral venous thrombosis following nitrous oxide usage. Investigation showed that her serum vitamin B12 level was <100 pg/mL (reference range 197-771 pg/mL), and homocysteine level was 100.6 µmol/L (reference range 5.0-15.0 µmol/L). After receiving a vitamin B12 supplement, both serum vitamin B12 and homocysteine levels returned to normal. No other risk factors for thrombophilia were detected. Previously reported cases predominantly demonstrated hyperhomocysteinemia. The most likely mechanism of her cerebral venous thrombosis was hyperhomocysteinemia due to vitamin B12 deficiency caused by nitrous oxide abuse. This finding supports the hypothesis that hyperhomocysteinemia can induce cerebral venous thrombosis.

Homocysteine levels, H-Hypertension, and the MTHFR C677T genotypes: A complex interaction

Background and objectives

High homocysteine levels are associated with increased risk of hypertension and stroke. Homocysteine is metabolized by the methylenetetrahydrofolate reductase (MTHFR). We aimed to investigate the levels of homocysteine and their association with hypertension, stroke, and antihypertensive medication usage in patients with different MTHFR C677T genotypes.

Methods and results

Genotype frequency of MTHFR polymorphism was performed, and plasma homocysteine levels were measured in 2,640 adult Lebanese patients. Hypertension, history of stroke, and list of medications were documented, among other clinical and demographic parameters. The TT mutant genotype and the T mutant allele of MTHFR were more prevalent in hyperhomocysteinemia (HHcy) and H-hypertensive (H-HTN, defined as hypertension with hyperhomocysteinemia) patients when compared to non-HHcy subjects and non H-HTN patients respectively. Homocysteine levels were significantly higher in hypertensive patients specifically among those on diuretics. A higher level of homocysteine was found in hypertensive patients with the MTHFR T allele compared to patients carrying the C allele. Among the T allele carriers, the average plasma homocysteine level was 13.3 ± 0.193 μmol/L for hypertensive subjects compared to 11.9 ± 0.173 μmol/L (non-hypertensives). Furthermore, homocysteine levels significantly correlated with stroke risk in patients with the T alleles.

Conclusions

We found an association of homocysteine with hypertension, hypertensive medication, and stroke risk among patients with the MTHFR T allele and the TT genotype. The association of diuretics therapy with higher homocysteine levels calls for routine measurements and therapeutic control of homocysteine in patients on diuretic, to improve health-related outcomes.

Hyperhomocysteinemia in acute hepatic porphyria (AHP) and implications for treatment with givosiran

INTRODUCTION

Homocysteine is a sulfur-containing amino acid formed in the intermediary metabolism of methionine. Amino acid metabolism and heme biosynthesis pathways are complexly intertwined. Plasma homocysteine elevation, hyperhomocysteinemia (HHcy), has been reported in patients with acute hepatic porphyria (AHP), a family of rare genetic disorders caused by defects in hepatic heme biosynthesis.

AREAS COVERED

This article summarizes published case series in which givosiran, a subcutaneously administered small interfering RNA approved for AHP treatment, appeared to exacerbate dysregulated homocysteine metabolism in patients with AHP. A comprehensive exploratory analysis of ENVISION trial data demonstrated that on a population level, givosiran increased homocysteine but with wide interpatient variations, and there is no proof of correlations between HHcy and changes in efficacy or safety of givosiran.

EXPERT OPINION

The strong correlation and co-increase of homocysteine and methionine suggest that HHcy associated with givosiran is likely attributable to the impaired trans-sulfuration pathway catalyzed by cystathionine β-synthase, which uses vitamin B6 as a cofactor. Data-based consensus supports monitoring total plasma homocysteine and vitamin B6, B12, and folate levels before and during givosiran treatment; supplementing with pyridoxine/vitamin B6 in patients with homocysteine levels >100 μmol/L; and involving patients with homocysteine levels >30 μmol/L in decisions to supplement.

Thromboembolic complications of recreational nitrous oxide (ab)use: a systematic review

The recreatinal use of nitrous oxide has become more common in recent years, especially in adolescents and young adults. It has been mainly associated with medical conditions like megaloblastic anemia and (myelo)neuropathy. We report on the thromboembolic complications, a less known side effect, associated with recreational inhalation of nitrous oxide. An extensive literature search was performed for publications reporting on the thromboembolic complications associated with recreational nitrous oxide abuse. Data about sex, age, location of thrombosis, laboratory findings, therapy and outcome were collected. A total of 13 case reports or case series were identified comprising a total of 14 patients. The reported thromboembolic side effects included deep venous thrombosis, pulmonary embolism, mesenterial-, portal and splenic vein thrombosis, cerebral sinus thrombosis, cortical vein thrombosis, stroke, acute myocardial infarction and peripheral artery thromboembolism. These side effects are possibly mediated by the interaction of nitrous oxide with vitamin B12, a cofactor of the methionine synthase complex, which eventually results in elevation of plasma levels of homocysteine. Despite being a known risk factor for cardiovascular disease, the exact pathophysiological mechanism remains unclear. Cessation of nitrous oxide inhalation is necessary to prevent recurrent thrombosis. Nitrous oxide abuse may thus result in a wide spectrum of thromboembolic complications. One should be aware of this etiology, especially in a young person with no obvious risk factors for cardiovascular disease. Spreading awareness is important to inform people about the potentially serious side effects associated with nitrous oxide inhalation.

A call to action: MTHFR polymorphisms should not be a part of inherited thrombophilia testing

Testing for polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene is still a standard part of thrombophilia testing in many laboratories. However, it is clear that these polymorphisms are not risk factors for arterial or venous thrombosis and therefore should not be part of thrombophilia testing. Eliminating MTHFR from thrombophilia testing will reduce patient concerns and health care costs.

Metabolism-mediated thrombotic microangiopathy and B12

Thrombotic microangiopathies (TMAs) are a group of life-threatening conditions requiring urgent management and characterized by a clinical triad of microangiopathic hemolytic anemia, thrombocytopenia, and ischemic tissue injury. Severe vitamin B12 (Cobalamin-Cbl) deficiency or defective cobalamin metabolism, particularly defects in intracellular B12 metabolism, may lead to a TMA-like picture. The latter has been termed metabolism-mediated TMA (MM-TMA). This confusing picture is mediated partly by ineffective erythropoiesis with significant red cell fragmentation resulting in a hemolytic pattern, coupled with reduced platelet production and endothelial injury with organ damage resulting from accumulated toxic byproducts of B12 dysmetabolism. However, unlike in classic thrombotic thrombocytopenic purpura, where therapeutic plasma exchange has to be initiated promptly, cases of MM-TMA can be treated, if diagnosed properly, with adequate B12 replacement.

Elevated lipoprotein A in acute on chronic CTEPH with cardiogenic shock: a case report

The natural history of most thrombi undergoes total or near total resolution, but the thrombi in chronic thromboembolic pulmonary hypertension (CTEPH) do not resolve completely and subsequently increase the pulmonary vascular resistance. We hypothesised that the elevated lipoprotein A in acute pulmonary embolism could lessen the autoresorption of the emboli and ultimately lead to CTEPH.

A Brief Review on Vitamin B12 Deficiency Looking at Some Case Study Reports in Adults

In the era of evidence-based medicine, the randomized clinical trial corresponds to the top step in the qualitative scale of the evidence available in the literature, while small series of cases or the description of individual cases occupy the last place. However, the latter represent an important part of clinical practice and have significantly influenced the evolution of medicine, contributing significantly to the advancement of scientific knowledge. Vitamin B₁₂ deficiency shares several common symptoms that affect several tissues and organs with health aliments, so its diagnosis could be unobvious for the broad array of its effects and investigation methods used. In this review, we focused our attention on some case reports related to the vitamin B₁₂ deficiency associated to anemia, neurologic disorders, and hyperhomocysteinemia. B₁₂ deficiency reversal is simply achieved by prompt therapy, even though it is not the same for several disorders.

Cerebral venous sinus thrombosis: a complication of nitrous oxide abuse

Nitrous oxide (NO) is an inhalant that has become increasingly popular as a recreational drug. While it is presumed to be harmless, a number of adverse effects of NO have been described. We discuss the case of a 24-year-old man with no medical history, who initially presented to the emergency department with progressive polyneuropathy caused by vitamin B12 deficiency after NO abuse. Two days after being discharged with hydroxocobalamin supplementation, the patient returned with a severe headache, blurry vision and slurred speech. Imaging revealed cerebral venous sinus thrombosis. Hypercoagulability workup showed slightly elevated homocysteine and normalised vitamin B12 after supplementation. Genetic testing showed a heterozygous prothrombin G20210A mutation. He was treated with low-molecular-weight heparin followed by dabigatran. We hypothesise that NO use may increase the risk of developing cerebral venous thrombosis, especially in patients with multiple risk factors and elevated homocysteine levels.

Retraction

Li, J., Tong, D., Wang, Y., Liu, Y., Zhang, X., Liu, N., Wang, S., Xu, Y., Li, Y., Yin, X., Liu, W. and Shao, Y. (2021), Neutrophil extracellular traps enhance procoagulant activity in patients with essential hypertension. J Thromb Haemost. https://doi.org/10.1111/jth.15210 The above article, published online on 12 December 2020 on Wiley Online Library (wileyonlinelibrary.com), has been retracted by mutual agreement among the authors, the journal co- Editors-in-Chief, David Lillicrap, MD, FRCPC and James Morrissey, PhD, the International Society on Thrombosis and Haemostasis, and Wiley Periodicals LLC The retraction has been issued due to unattributed overlap between this article and the following article published in Thrombosis Research, "Neutrophil extracellular traps exacerbate coagulation and endothelial damage in patients with essential hypertension and hyperhomocysteinemia" by Li, J-H, Tong, D-X, Wang, Y, Gao, L, Liu, Y, Zhang, X-H, Chen, W-J, Chi, J-Y, Liu N, Yang, K, Wang, S-P, Xu, Y, Li, Y, Yin, X-H, Liu, W-X. Volume 197, 2021, pages 36-43. https://doi.org/10.1016/j.thromres.2020.10.028.

Thrombosis associated with mycoplasma pneumoniae infection (Review)

Mycoplasma pneumoniae is a common pathogen causing respiratory infections in children and adults. In addition to respiratory diseases, Mycoplasma pneumoniae is also involved in numerous extrapulmonary diseases. Thrombosis is an extrapulmonary manifestation associated with Mycoplasma pneumoniae infection. In recent years, an increasing number of case reports have been published identifying thrombosis secondary to Mycoplasma pneumoniae infection. In the present study, the available relevant literature in English available on PubMed, Medline and Web of Science was consulted. The results of the present study demonstrated that in patients with thrombosis caused by Mycoplasma pneumoniae infection, some of the factors causing thrombosis are transient and some are due to hereditary thrombophilia. Following timely treatment, the majority of patients recovered completely but some patients had a poor prognosis. The present review focuses on the pathogenesis, clinical features, treatment and prognosis of this crucial issue, which contributes toward the understanding of the disease.

Homocysteine is potential serological marker for predicting the risk of deep venous thrombosis of the lower extremities in patients received operation of lower limb fracture

Objective

The aim of the study is to investigate the correlations among serum homocysteine (Hcy), D-dimer, and the risk of developing deep venous thrombosis (DVT) of the lower extremities in patients who underwent operation for lower limb fracture.

Methods

Seventy-five cases who underwent operation for lower limb fracture were included and further divided into DVT group (n = 26) and control group (n = 49) based on post-DVT diagnostic criteria. The serum Hcy and D-dimer were examined 48 h after operation. The serum Hcy and D-dimer levels were compared between the two groups. The correlation between serum Hcy and D-dimer was investigated by the Pearson correlation test. The receiver-operating characteristic (ROC) curve was applied to evaluate the diagnostic performance of serum Hcy and D-dimer as serological markers for DVT.

Results

The serum Hcy concentrations were 11.96 ± 3.98 μmol/L and 7.92 ± 3.27 μmol/L for DVT and control groups, respectively, with statistical difference (t = 4.72, P < 0.01). The serum D-dimer in the DVT group was significantly higher than that of the control group (8.99 ± 4.50 vs 1.70 ± 2.11) μg/mL with statistical difference (t = 9.56, P < 0.01). Line regression analysis indicated that serum Hcy was positively correlated with serum D-dimer concentration and can be demonstrated by the equation of Y = 0.6651*X + 1.036 for the DVT group. Using serum Hcy as the biomarker for predicting DVT, the prediction sensitivity and specificity were 76.92 and 71.44%, respectively, with the AUC of 0.7804 under the cut-point of 9.54 μmol/L. For serum D-dimer, the prediction sensitivity and specificity were 96.15 and 73.47%, respectively, with the area under the ROC (AUC) of 0.9455 under the cut-point of 1.66 μg/mL.

Conclusion

Serum Hcy was significantly elevated in DTV patients, and hence, it can be applied as a serological marker for DVT prediction in patients who underwent operation for lower limb fracture. However, the DVT prediction performance of serum Hcy was inferior to D-dimer especially for diagnostic sensitivity.

Homozygous methylentetrahydrofolate reductase C667T genotype anticipates age at venous thromboembolism by one decade

The aim of the study was to compare age at first venous thromboembolism (VTE), plasma homocysteine and activated partial thromboplastin time ratio (aPTTr) amongst unprovoked VTE patients with the methylentetrahydrofolate reductase (MTHFR) C667T genotypes, and to identify predictors of age at first VTE, of plasma homocysteine and of the aPTTr; to evaluate whether heterozygous or homozygous prothrombin (PT) G20210A mutation lowered the age at first VTE when associated with MTHFR TT. Retrospective cohort study on 259 MTHFR TT, 76 MTHFR TC and 64 MTHFR CC participants with unprovoked VTE; each participant contributed age, sex, age at VTE, history of dyslipidaemia, hypertension, smoking, homocysteine (measured by enzyme immunoassay) and aPTTr (measured by standard coagulation assay). Age at first VTE was lower in MTHFR TT than MTHFR TC and CC (41 ± 14 vs. 50 ± 16 vs. 51 ± 12 years, respectively, P < 0.0001); plasma homocysteine was higher in MTHFR TT than in the other groups (22 ± 21 vs. 12 ± 11.6 vs. 10 ± 3.3 μmol/l, respectively, P = 0.0005) whilst aPTTr was not different. MTHFR TT independently predicted age at first VTE (P = 0.001), plasma homocysteine (P < 0.0001) alongside sex (P = 0.0007), age and smoking (P = 0.03 for both). Compound MTHFR TT with PT GA or AA had no lowering effect on age at first VTE compared with MTHFR TT alone (41 ± 13 vs. 41 ± 14 years). Plasma homocysteine inversely related to aPTTr in the MTHFR TT group (P = 0.003). MTHFR TT anticipates age at first VTE by an average of 10 years compared with MTHFR TC and CC genotypes.

[Thromboembolic event and metabolic hyperhomocysteinemia: A case report and review of literature]

INTRODUCTION

Venous thromboembolic diseases have an incidence of 1.57/1000. Among patients under 50 years old, thrombophilia is assessed, the indications for which are increasingly stringent. Today, the need of plasma homocysteine assay is uncertain.

OBSERVATION

Our case is a 42 year-old man, in whom a pulmonary embolism associated with macrocytosis made us discover a B12 deficiency secondary to Biermer's disease. In the literature, patients are men with an average age limit to the realisation of the assessment of thrombophilia. Not all of these patients had any causal other than hyperhomocysteinemia secondary to Biermer's disease. The support is not detailed.

CONCLUSION

Hyperhomocysteinemia is probably not the only thromboembolic factor. The patient received anticoagulation and vitamin B12 supplementation. A good reading of the complete blood count is essential.

Cystathionine β-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 β-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 β-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 β-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.

Hyperhomocysteinemia and Pulmonary Embolism in a Young Male

The association of hyperhomocysteinemia with thrombosis has provoked debate in the medical literature. Although studies have found associations between moderate homocysteine elevations and thrombotic events, others dispute this relationship. We present herein the case of a 24-year-old male who presented with unprovoked bilateral submassive pulmonary emboli. Extensive hypercoagulability workup was notable for an elevated homocysteine level, in addition to low vitamin B12 and folate levels. Of note, the patient had a history of small bowel resection after trauma, which may have contributed to the aforementioned metabolic derangements, potentially increasing his risk for thrombosis and interfering with the efficacy of his anticoagulation.

Homocysteine inhibits the viability and migration ability of human umbilical vein endothelial cells by downregulating the expression of vascular endothelial growth factor

The current study aimed to explore the effect of homocysteine (Hcy) on the viability and migration ability of human umbilical vein endothelial cells (HUVECs), as well as to examine the underlying mechanism. The association between the expression level of Hcy and lower extremity deep vein thrombosis (DVT) was detected in clinical samples collected from patients. In addition, the effect of Hcy on the viability and migration ability of HUVECs was detected by cell counting kit-8 and Transwell assays, respectively, while vascular endothelial growth factor (VEGF) expression was measured in order to verify the effect of Hcy on VEGF. The results indicated that the serum Hcy levels in DVT patients were significantly increased. In vitro experiments also confirmed that Hcy was able to significantly inhibit the viability and migration ability of HUVECs, and downregulate the expression of VEGF in these cells. Furthermore, the inhibitory effect of Hcy on HUVEC viability and migration ability was achieved by downregulating the expression of VEGF using small interfering RNA transfection. In conclusion, Hcy inhibited the viability and migration ability of HUVECs by downregulating the expression of VEGF. This may underlie the high incidence of DVT in patients with hyperhomocysteinemia.

Risk of Recurrent Venous Thromboembolism After an Initial Episode: Risk Stratification and Implications for Long-term Treatment

PURPOSE OF REVIEW

Venous thromboembolism (VTE) is a common condition with significant associated morbidity and mortality. Recurrent VTE after an initial episode is a preventable medical condition. The following review discusses data supporting recurrence risk estimates after an initial VTE episode as well as treatment strategies to mitigate risk of recurrent VTE.

RECENT FINDINGS

This review particularly highlights methods for stratifying the risk of recurrent VTE and recent studies that have evaluated direct oral anticoagulants for the prevention of recurrent VTE. Risk assessment for VTE recurrence should guide anticoagulation duration. In patients who present with unprovoked VTE events, there remains a high risk of recurrence that is significantly mitigated with extended duration anticoagulation with either a vitamin K antagonist or direct oral anticoagulant.

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.