Facts and Recommendations about Total Homocysteine Determinations: An Expert Opinion

Highly selective fluorescent probe for cysteine via a tandem reaction and its bioimaging application in HeLa cells

Cysteine, as a vital endogenous small molecule mercaptan, plays a crucial role in various physiological processes. The high sensitivity and selectivity of fluorescent probes provide a method to monitor cysteine, which is helpful to understand the mechanism of cysteine in physiological processes more comprehensively. However, the detection of cysteine can be interfered by other small molecule biothiols. Therefore, the design of fluorescent probe based on the structural characteristics and reactivity of cysteine has become research focus currently. Given the biological compatibilities, biological targets, the metabolic pathway of 3-hydoxythalidomide, and its unique fluorescent properties, herein, we have designed a chemodosimeter, 2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl acrylate, for the detection of cysteine based on a tandem reaction of thiol-ene click chemistry and aminolysis involving 3-hydroxythalidomide as a parent compound. Experimental data exhibited that the probe showed unique selectivity and sensitivity for cysteine over other amino acid and biothiols. In addition, the fluorescent intensity at 511 nm increased linearly as a function of cysteine concentration in the range of 0-6 × 10-7 M (regression factor, R2 = 0.999), with a limit of detection of 6.1 nM. The sensing mechanism was confirmed through 1H NMR titration and density functional theory calculations. Additionally, the probe was also successfully utilized for the detection of cysteine in sewage and for bioimaging in HeLa cells.

A Novel Methacryloyl-Masked NIR Fluorescent Probe for Detection of Cysteine and Its Application in Bioimaging

Cysteine (Cys) detection is recognized as an essential element in this investigation due to the critical function of Cys in several physiological processes in living organisms. A new NIR fluorescent probe SNC-Cys has been synthesized by incorporating a five-membered malononitrile derivatized ring as an electron withdrawing group, and a methacryloyl group detection moiety for cysteine. After adding Cys, SNC-Cys shows an emission of 654 nm and further works as a "Turn-on" probe via ICT photomechanism. SNC-Cys has high sensitivity and selectivity for Cys (LOD=0.46 μM) and can discriminate it from other closely related amino acids, molecules with structural similarity, and in some cases very close functional group likeness. Thus, these results allow the effective imaging of Cys in living A549 cells which indicates good cell permeability and high applicability in live cell imaging. This study anticipates that SNC-Cys could be an aid in the detection of Cys-relevant diseases.

BT-DNBS: a novel cyanine-based turn-on fluorescent probe with large Stokes shift for sensitive and selective detection of biothiols in live-cell imaging

Detecting biothiols like glutathione (GSH), homocysteine (Hcy), and cysteine (Cys) is key to understanding their roles in health and disease. We developed BT-DNBS, a cyanine-based turn-on fluorescent probe with a dinitrobenzenesulfonyl (DNBS) quencher group. Upon biothiol interaction, the quencher is cleaved, restoring fluorescence. The resulting probe BT-NH shows a maximum emission wavelength at 630 nm and a large Stokes shift (≈200 nm), enhancing detection accuracy. Low cytotoxicity and high time resolution make BT-DNBS suitable for live-cell imaging. Imaging of A431 cells confirmed intracellular biothiol detection, with NEM pre-treatment reducing fluorescence, verifying specificity. BT-DNBS holds promise for biomedical research, particularly in disease diagnostics.

Hyperhomocysteinemia is linked to MASLD

BACKGROUND AND AIMS

Homocysteine (Hcy) levels are elevated in different conditions, including cardiovascular diseases (CVD), diabetes, and metabolic-associated steatotic liver disease (MASLD). In this observational retrospective study, we analyzed Hcy levels in a population of 901 outpatients, considering its putative etiological role in MASLD.

METHODS

A total of 901 outpatients underwent physical and biochemical evaluations. Abdominal and carotid ultrasound were performed to assess liver steatosis, carotid intima-media thickness (IMT) and presence of atherosclerotic plaque.

RESULTS

Hyperhomocysteinemia (HHcy) was identified in 140 subjects (16 %). Patients with HHcy showed glucose metabolism impairment (p < 0.001), altered lipid profile (p < 0.001), low Vitamin D levels (p < 0.0001), increased cardiovascular risk (p < 0.001). We then investigated the relationship between Hcy and MASLD (OR=3.6, p < 0.0001), finding that the relationship remained significant also when accounting for confounding variables (age, sex) (OR=3.2, p < 0.0001). Hcy values were significantly higher (p < 0.0001) in patients with MASLD (n = 78, 29.4 ± 10.1μmol/l) compared to those without MASLD (20.4 ± 4.8 1μmol/l). Furthermore, in MASLD patients we found a direct correlation between Hcy level and waist circumference (r = 0.3, p < 0.001) and an inverse correlation with both HDL-c (r=-0.4, p < 0.001) and Vitamin D levels (r=-0.24, p < 0.05).

CONCLUSIONS

Our data suggest an intriguing scenario whereby HHcy is present in patients with MASLD and is associated to lower vitamin D and altered glucose and lipid profile. Thus, considering Hcy levels may help clinicians with the management of patients with increased MASLD risk.

The application and interpretation of laboratory biomarkers for the evaluation of vitamin B12 status

Vitamin B12 (cobalamin; B12) is an essential micronutrient, but deficiency is common. The prompt diagnosis and treatment of B12 deficiency protects against megaloblastic anaemia, neuropathy and neuropsychiatric changes. Biomarkers of B12 status include the measurement of serum B12 (also known as total B12 or serum cobalamin), holotranscobalamin (holoTC or 'active B12'), methylmalonic acid (MMA) and total plasma homocysteine (Hcy). There is no 'gold standard' test for deficiency and the sensitivity and specificity of each biomarker for the evaluation of B12 status is affected by analytical and biological factors that may confer a high degree of diagnostic uncertainty. Limited access to technical and clinical expertise can lead to an over-reliance on the serum B12 test, which is readily available and highly automated. In some cases, the sequential use of different B12 status biomarkers or the calculation of a composite B12 status score, derived from a panel of B12 biomarkers and adjusted for folate status and age, can be used to detect deficient states that may otherwise be overlooked when using a single biomarker approach. This review summarizes the utility of B12-related biomarkers and describes approaches to their application and interpretation.

A systematic review and meta-analysis of functional vitamin B12 status among adult vegans

The dietary intake of vitamin B12 among unsupplemented vegans is notably lower compared to both vegetarians and omnivores. Prolonged low intakes of vitamin B12, such as seen in those adhering to a vegan diet, lead to physiological deficiency of vitamin B12 and an elevated risk of B12-related morbidity. However, while serum B12 serves as a conventional biomarker for assessing B12 status, its utility is limited given its sensitivity and specificity in ascribing physiological deficiency of B12 and the functional vitamin B12 status of those adhering to vegan diets is unclear. We conducted a systematic review and meta-analysis using data based on the full panel of biomarkers of vitamin B12 status to test whether adherence to a vegan diet is associated with an elevated risk of functional vitamin B12 deficiency compared to vegetarian or omnivorous diets. In addition, subgroup analysis was carried out to look at the effect of vitamin B12 supplement use on B12 status among vegans. Our search identified 4002 records, of which 19 studies met the inclusion criteria for the systematic review and 17 studies were taken forward for the meta-analysis. Meta-analysis results revealed significantly lower serum B12, pmol/ (-0.72 [-1.26, -0.18]; p = 0.01) and elevated total homocysteine, μmol/L (tHcy) (0.57 [0.26, 0.89]; p < 0.001) concentrations, alongside elevated methylmalonic acid, nmol/L (MMA) (0.28 [-0.01, 0.57]; p = 0.06) and lower holotranscobalamin, pmol/ (HoloTC) (-0.42 [-0.91, 0.07]; p = 0.09) levels among vegan adults compared to omnivores, indicating increased functional B12 deficiency in addition to low vitamin B12 status in vegan adults. There were no differences between vegans and vegetarians in HoloTC (0.04 [-0.28, 0.35]; p = 0.814) or MMA (-0.05 [-0.29, 0.20]; p = 0.708), but differences were found in serum B12 (-0.25 [-0.40, -0.10]; p = 0.001) and for tHcy (0.24 [0.09, 0.39]; p = 0.002) concentrations. Subgroup analyses indicated that the use of vitamin B12 supplements among vegans contributes to significant improvements in all biomarker concentrations compared to their unsupplemented counterparts. Our findings underscore the need for improved strategies to redress poor vitamin B12 status with appropriate B12 supplementation use among those adhering to vegetarian and vegan diets.

Clinical, biochemical, molecular characteristics and clinical outcome of hyperhomocysteinemia in Malaysian children

BACKGROUND

Hyperhomocysteinemia can be due to various abnormalities of the complex interaction of methionine, folate and vitamin B12. It has been known to be a cardiovascular risk factor. This study aims to review the clinical presentation, underlying causes and clinical outcome in paediatric patients diagnosed with significant hyperhomocysteinemia in Malaysia.

DESIGN AND METHODS

Data were obtained from the medical records and the laboratory information system. Paediatric patients with significant hyperhomocysteinemia were identified from a selective high-risk screening of 96,721 patients, performed between 2010 and 2022. Inclusion criteria for the study were paediatric patients with significant hyperhomocysteinemia (>40 µmol/L).

RESULTS

Sixteen patients were identified. The average total homocysteine (tHcy) and methionine were 269 µmol/L and 499 µmol/L in cystathionine β-synthase deficiency (CBS), 127 µmol/L and 29 µmol/L in patients with remethylation defects and 390 µmol/L and 4 µmol/L in congenital B12 deficiency. We found c.609G>A as the most prevalent mutation in MMACHC gene and possible novel mutations for CBS (c.402del, c.1333C>T and c.1031T>G) and MTHFR genes (c.266T>A and c.1249del). Further subclassification revealed CBS was 5/16 patients (31 %), remethylation defects was 9/16 (56 %) and congenital B12 deficiency was 2/16 (13 %). All patients received standard treatment and regular monitoring of the main biomarkers. The average age at the time of diagnosis were 9.2 years (CBS) and 1.2 years (remethylation defects). Congenital B12 deficiency had slight delay in milestones, remethylation defects had mild to moderate learning disabilities, CBS had variable degree of intellectual disability, delayed milestones, ophthalmological abnormalities, and thrombosis at an early adolescent/adulthood.

CONCLUSIONS

The majority of significant hyperhomocysteinemia in Malaysian children was due to remethylation defects. Screening for hyperhomocysteinemia in Malaysian children is recommended for earlier treatment and improved clinical outcome.

Homocysteine, neurodegenerative biomarkers, and APOE ε4 in neurodegenerative diseases

INTRODUCTION

Elevated plasma homocysteine (Hcy) is associated with an increased risk of developing neurodegenerative diseases; however, its relationship with the apolipoprotein E (APOE) ε4 allele has not been well characterized.

METHODS

Participants clinically diagnosed with Alzheimer's disease or mild cognitive impairment (AD/MCI), frontotemporal dementia, Parkinson's disease, or cerebrovascular disease were stratified by the presence of the APOE ε4 allele. Volumetric magnetic resonance imaging, plasma amyloid/tau/neurodegeneration biomarkers, and cognitive performance were quantified.

RESULTS

Across all diagnostic groups, Hcy was associated with lower brain parenchymal fraction and greater neurofilament light chain in APOE ε4 non-carriers only. In AD/MCI, Hcy was associated with phosphorylated tau 217 in APOE ε4 non-carriers, but not in carriers. Exploratory analyses revealed interactions between Hcy and APOE ε4 on memory and visuospatial function.

DISCUSSION

Hcy may contribute to neurodegeneration depending on the presence of the APOE ε4 allele and specific disease processes. Trials on vitamin B12 supplementation may consider stratifying by APOE genotype. Highlights Homocysteine (Hcy) was associated with neurodegenerative biomarkers across disease groups. Relationships with Hcy were predominantly found in apolipoprotein E (APOE) ε4 non-carriers. In Alzheimer's disease, associations between Hcy and phosphorylated tau 217 were found in APOE ε4 non-carriers only. Significant interactions existed between Hcy and APOE ε4 status on cognition.

The L-Arginine pathway may act as a mediator in the association between impaired one- carbon metabolism and hypertension

Elevated fasting plasma total homocysteine (tHcy) and the methylenetetrahydrofolate reductase C677T polymorphism (rs1801133) have been associated with hypertension. Whether the L-Arginine pathway is involved, is unclear. We aimed to investigate whether the association between tHcy, the rs1801133 polymorphism and hypertension involves the L-Arginine pathway. THcy, plasma folate and cobalamin, erythrocyte glutathionine reductase activation coefficient, rs1801133 genotype, plasma L-Arginine, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) were determined in a cross-sectional study of 788 adults (aged 18 to 75), randomly selected from 2 town population registers. Participants participated in a medical checkup and provided a fasting blood sample. Associations between tHcy, rs1801133 genotype and L-Arginine pathway metabolites were assessed by multiple linear regression analysis and whether the tHcy and rs1801133 genotype are associated with hypertension via the L-Arginine pathway was investigated using mediation analysis. tHcy was positively associated with ADMA (B=0.003; SE=0.001; P<0.001) and SDMA (B=0.007; SE=0.002; P<0.001) and negatively associated with the L-Arginine/ADMA (B=-1.140; SE=0.451; P<0.05) and ADMA/SDMA (B=-0.006; SE=0.003; P<0.05) ratios. The MTHFR 677 CT vs CC genotype was negatively associated with ADMA (B=-0.013; SE=0.007; P<0.05) and with SDMA (B=-0.029; SE=0.013; P<0.05) in participants under 50 years. Each standard deviation increase (37.6) in the L-Arginine/ADMA ratio was associated with reduced hypertension risk (OR [95%CI], 0.6 [0.5, 0.8]). Mediation analysis showed that tHcy and ADMA were mediators in the association between the rs1801133 TT vs CC genotypes and hypertension. Our results support the L-Arginine pathway as a mediator in the association of impaired One-Carbon metabolism and hypertension.

Folate and cobalamin status, indicators, modulators, interactions, and reference ranges from early pregnancy until birth: the Reus-Tarragona birth cohort study

BACKGROUND

Folate and cobalamin status, although essential for pregnancy, are not routinely monitored in prenatal care.

OBJECTIVES

To investigate folate and cobalamin status and determinants throughout pregnancy, in the absence of mandatory folic acid (FA) fortification.

METHODS

In a cohort study of 831 mothers recruited at <12 gestational weeks (GW), plasma folate, total homocysteine (tHcy), cobalamin, holotranscobalamin (holoTC), methylmalonic acid (MMA), red blood cell folate (RBCF), and the combined cobalamin status indicator (cB12) were determined at ≤12, 15, 24-27, 34 GW, labor and in the cord. Single nucleotide polymorphisms affecting folate and cobalamin status were determined. FA, cobalamin, micronutrient supplement use, and dietary folate and cobalamin intake (food frequency questionnaire) were recorded. Folate and cobalamin status predictors were assessed by multiple linear regression analysis.

RESULTS

Only 36.1% of the participants took FA preconceptionally and 47.4% and 7.3% had suboptimal RBCF (<906 nmol/L) and plasma cobalamin status (≤221 pmol/L), respectively, at ≤12 GW. RBCF determinants included planned pregnancy, FA supplementation, plasma cobalamin, and methylenetetrahydrofolate (MTHFR) 677C>T genotype. Cobalamin supplementation was positively associated with plasma cobalamin and early holoTC. Smoking and BMI were inversely associated with plasma cobalamin and early holoTC, but none were associated with MMA. Only participants with the MTHFR 677TT genotype, exceeding FA supplement recommendations, improved their folate status (interaction term: B (95% CI):0.15 (0.01, 0.29), P = 0.032). Smoking was inversely associated with plasma cobalamin status in participants with the methionine synthase reductase (MTRR) 524CC genotype only (interaction term:0.07 (0.01, 0.04), P = 0.014). Mothers with low early pregnancy cobalamin status and also those with bigger newborns, had lower cobalamin status at labor.

CONCLUSIONS

Suboptimal early pregnancy folate or cobalamin status affected 47.4% and 7.3% of the participants, respectively. The MTHFR 677TT genotype predicted folate status throughout pregnancy. Smoking and BMI were negatively associated with cobalamin status throughout pregnancy. Clinical Trial Registry number and website where it was obtained: NCT01778205. www.

CLINICALTRIALS

gov.

Research Progress of Fluorescent Probes for Detection of Glutathione (GSH): Fluorophore, Photophysical Properties, Biological Applications

Intracellular biothiols, including cysteine (Cys), glutathione (GSH), and homocysteine (Hcy), play a critical role in many physiological and pathological processes. Among them, GSH is the most abundant non-protein mercaptan (1-10 mM) in cells, and the change in GSH concentration level is closely related to the occurrence of many diseases, such as Parkinson's disease, Alzheimer's disease, and neurological diseases. Fluorescent probes have attracted much attention due to their advantages of high specificity, high sensitivity, high selectivity, low cost, and high quantum yield. Methods that use optical probes for selective detection of GSH in vitro and in vivo are in high demand. In this paper, we reviewed the most recent five years of research on fluorescence probes for the detection of GSH, including the specific detection of GSH, dual-channel identification of GSH and other substances, and the detection of GSH and other biothiols. According to the type of fluorophore, we classified GSH fluorescent probes into eight classes, including BODIPY, 1,8-Naphthalimide, coumarin, xanthene, rhodamine, cyanine, benzothiazoles, and others. In addition, we roundly discuss the synthesis, detection mechanism, photophysical properties, and biological applications of fluorescent probes. We hope that this review will inspire the exploration of new fluorescent probes for GSH and other related analyses.

Estimating prevalence of classical homocystinuria in the United States using Optum's de-identified market clarity data

Background and objectives

Prevalence estimates for classical homocystinuria (HCU) are variable and likely underestimated due to underdiagnosis. Claims data represent a strong but seldom used resource to analyze prevalence of HCU. The aim of this study was to estimate a prevalence range of HCU in the US utilizing a combination of diagnosis codes, total homocysteine levels, and clinical presentations indicative of HCU.

Methods

This was a non-interventional retrospective cohort study, using Optum's de-identified Market Clarity Data, with a patient identification period from January 01, 2016, through September 30, 2021. An algorithm was developed to identify 2 cohorts of patients using broad and strict definitions of HCU. The index date was the date within the identification period on which the first criterion was met for the inclusion criteria. Baseline demographics, clinical characteristics, and complications were assessed and summarized using descriptive statistics. Crude and standardized prevalence estimates were calculated.

Results

There were 3880 and 633 patients that met the relevant inclusion criteria for the broad and strict cohorts, respectively. The projected US prevalence of HCU was calculated to be 17,631 and 3466 based on the broad and strict definitions, respectively. The average annual standardized prevalence across 2016-2020 was 5.29 and 1.04 per 100,000 people for the broad and strict cohorts, respectively.

Conclusions

Prevalence estimates of HCU vary depending on databases or datasets used and identification criteria. Many patients with clinical presentations suggesting a diagnosis of HCU did not have an associated diagnosis, potentially indicating underdiagnosis or underreporting. Future research should study alternative methods, such as the identification algorithm in our analysis, to better diagnose and understand the true prevalence of HCU.

Serum Vitamin B12 Levels as a Risk Factor and Prognostic Marker in Patients With Acute Ischemic Stroke at a Tertiary Care Center in Northern India: A Case-Control Study

Objective Stroke is a leading cause of death and disability globally, with its incidence, prevalence, and mortality rising significantly over the past decades. Beyond traditional risk factors, vitamin B12 has garnered attention for its role in stroke prevention due to its influence on homocysteine metabolism. Deficiencies in vitamin B12 are linked to hyperhomocysteinemia, which increases the risk of ischemic stroke. This study aims to compare vitamin B12 and homocysteine levels in stroke patients versus control subjects. Methodology This observational case-control study was conducted at King George's Medical University (KGMU), Lucknow, involving 75 acute ischemic stroke patients and 75 age- and sex-matched controls. Serum vitamin B12 and homocysteine levels were measured, and stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) score. The modified Rankin scale (MRS) evaluated functional outcomes at discharge. Statistical analysis was performed to identify associations between vitamin B12 levels, stroke severity, and patient outcomes. Results Stroke patients had significantly lower vitamin B12 levels (194.24 ± 91.11 pmol/L) and higher homocysteine levels (16.33 ± 3.29 µmol/L) compared to controls (271.13 ± 91.19 pmol/L and 9.76 ± 4.55 µmol/L, respectively). Vitamin B12 levels were lower, and homocysteine levels were higher in patients who died during the study. Additionally, vitamin B12 levels were negatively correlated with MRS scores at discharge and 28 days post-discharge, and positively correlated with NIHSS scores, indicating worse outcomes in patients with lower vitamin B12 levels. Conclusions  This study demonstrates a significant association between vitamin B12 deficiency and the occurrence and severity of ischemic stroke. Lower vitamin B12 levels correlated with higher stroke severity and poorer functional outcomes, highlighting the potential role of vitamin B12 in stroke management. Further research is needed to explore the therapeutic implications of vitamin B12 supplementation in reducing stroke risk and improving patient outcomes.

The effect of methionine and folic acid administered in ovo on the blood biochemical parameters of chickens (Gallus gallus domesticus)

Methionine is one of the most frequently supplemented amino acids in raising of poultry. However, an overdose of methionine can cause hyperhomocysteinemia. Folic acid, taking part in the process of homocysteine remethylation, is a factor affecting the reduction of the concentration of this amino acid. The study was carried out in 2 stages. The experiment of step I was to investigate the effect of methionine and/or folic acid administration in ovo in the early stage of embryogenesis (E4), and the experiment of the second stage - in the late stage of embryogenesis (E17) on the following biochemical parameters of chicken blood: glucose concentration in whole blood and concentration of homocysteine and uric acid in plasma of domestic chickens (Gallus gallus domesticus). Our results confirm that methionine supplementation may increase the concentration of uric acid and homocysteine. Moreover, we demonstrated that folic acid administered during embryogenesis decreased homocysteine concentration, also in groups simultaneously supplemented with methionine, especially in the initial stage of postnatal life of the bird.

The Role of Cobalamin in Multiple Sclerosis: An Update

Multiple sclerosis (MS) is a neurodegenerative condition that results in axonal and permanent damage to the central nervous system, necessitating healing owing to autoimmune reactions and persistent neuroinflammation. Antioxidant and anti-inflammatory drugs are essential for the management of oxidative stress and neuroinflammation. Additionally, multivitamin supplementation, particularly vitamin B12 (cobalamin), may be beneficial for neuronal protection. Although there is no documented connection between vitamin B12 deficiency and MS, researchers have explored its potential as a metabolic cause. This review highlights the therapeutic benefits of cobalamin (Cbl) in patients with MS.

A Mendelian randomisation, propensity score matching study to investigate causal association between serum homocysteine and intracranial aneurysm

BACKGROUND AND PURPOSE

Recent observational studies have reported that serum total homocysteine (tHcy) is associated with intracranial aneurysms (IAs). However, the causal effect of tHcy on IAs is unknown. We leveraged large-scale genetic association and real-world data to investigate the causal effect of tHcy on IA formation.

METHODS

We performed a two-sample Mendelian randomisation (MR) using publicly available genome-wide association studies summary statistics to investigate the causal relationship between tHcy and IAs, following the recommendations of the Strengthening the Reporting of Observational Studies in Epidemiology-MR statement. Furthermore, a propensity score matching (PSM) analysis was conducted to evaluate the detailed effects of tHcy on risk of IA formation by utilizing real-world multicentre data, including 9902 patients with and without IAs (1:1 matched). Further interaction and subgroup analyses were performed to elucidate how tHcy affects risk of IA formation.

RESULTS

MR analyses indicated that genetically determined tHcy was causally associated with IA risk (OR, 1.38, 95% CI 1.07 to 1.79; p=0.018). This is consistent with the more conservative weighted median analysis (OR, 1.41, 95% CI 1.03 to 1.93; p=0.039). Further sensitivity analyses showed no evidence of horizontal pleiotropy or heterogeneity of single nucleotide polymorphisms in causal inference. According to the PSM study, we found that, compared with low tHcy (≤15 µmol/L), moderate tHcy (>15-30 µmol/L) (OR 2.13, 95% CI 1.93 to 2.36) and high tHcy (>30 µmol/L) (OR 3.66, 95% CI 2.71 to 4.95) were associated with a higher IA risk (p trend <0.001). Subgroup analyses demonstrated significant ORs of tHcy in each subgroup when stratified by traditional cardiovascular risk factors. Furthermore, there was also a synergistic effect of tHcy and hypertension on IA risk (p interaction <0.001; the relative excess risk due to interaction=1.65, 95% CI 1.29 to 2.01).

CONCLUSION

Both large-scale genetic evidence and multicentre real-world data support a causal association between tHcy and risk of IA formation. Serum tHcy may serve as a biomarker to identify high-risk individuals who would particularly benefit from folate supplementation.

Vitamin B12-Related Biomarkers

BACKGROUND

Adult vitamin B12 (B12) deficiency may present itself with nonspecific mainly neurological symptoms, and thus plasma biomarkers are often judged to be of major importance in the further diagnostic process. Four biomarkers are of special relevance: total B12, holotranscobalamin (the part of B12 bound to the active transport protein, transcobalamin, also named holoTC or active B12) and the 2 so-called metabolic markers that accumulate if B12 is lacking, methylmalonic acid (MMA) and homocysteine.

OBJECTIVE

This article briefly reviews the inherent limitation of biomarkers, discusses its use in establishing the diagnosis and cause of B12 deficiency, and when following or discontinuing treatment with B12.

METHODS

The review is based on published papers, but also on knowledge gained from working within the area.

CONCLUSION

It is concluded that a combination of a B12 and a metabolic marker, for example, total B12 and MMA, may prove most useful in daily practice. An unexpectedly high level of total B12 is most often of no clinical importance, though sometimes related to the presence of underlying cancer. Measurement of total B12 is of limited value in patients on treatment with pharmacological doses of B12 but may be helpful if B12 treatment is discontinued.

Leukoaraiosis: Epidemiology, Imaging, Risk Factors, and Management of Age-Related Cerebral White Matter Hyperintensities

Leukoaraiosis (LA) manifests as cerebral white matter hyperintensities on T2-weighted magnetic resonance imaging scans and corresponds to white matter lesions or abnormalities in brain tissue. Clinically, it is generally detected in the early 40s and is highly prevalent globally in individuals aged >60 years. From the imaging perspective, LA can present as several heterogeneous forms, including punctate and patchy lesions in deep or subcortical white matter; lesions with periventricular caps, a pencil-thin lining, and smooth halo; as well as irregular lesions, which are not always benign. Given its potential of having deleterious effects on normal brain function and the resulting increase in public health burden, considerable effort has been focused on investigating the associations between various risk factors and LA risk, and developing its associated clinical interventions. However, study results have been inconsistent, most likely due to potential differences in study designs, neuroimaging methods, and sample sizes as well as the inherent neuroimaging heterogeneity and multi-factorial nature of LA. In this article, we provided an overview of LA and summarized the current knowledge regarding its epidemiology, neuroimaging classification, pathological characteristics, risk factors, and potential intervention strategies.

Highly-ordered assembled organic fluorescent materials for high-resolution bio-sensing: a review

Organic fluorescent materials (OFMs) play a crucial role in the development of biosensors, enabling the extraction of biochemical information within cells and organisms, extending to the human body. Concurrently, OFM biosensors contribute significantly to the progress of modern medical and biological research. However, the practical applications of OFM biosensors face challenges, including issues related to low resolution, dispersivity, and stability. To overcome these challenges, scientists have introduced interactive elements to enhance the order of OFMs. Highly-ordered assembled OFMs represent a novel material type applied to biosensors. In comparison to conventional fluorescent materials, highly-ordered assembled OFMs typically exhibit robust anti-diffusion properties, high imaging contrast, and excellent stability. This approach has emerged as a promising method for effectively tracking bio-signals, particularly in the non-invasive monitoring of chronic diseases. This review introduces several highly-ordered assembled OFMs used in biosensors and also discusses various interactions that are responsible for their assembly, such as hydrogen bonding, π-π interaction, dipole-dipole interaction, and ion electrostatic interaction. Furthermore, it delves into the various applications of these biosensors while addressing the drawbacks that currently limit their commercial application. This review aims to provide a theoretical foundation for designing high-performance, highly-ordered assembled OFM biosensors suitable for practical applications. Additionally, it sheds light on the evolving trends in OFM biosensors and their application fields, offering valuable insights into the future of this dynamic research area.

Health Patterns across Adulthood: An Age-Based Investigation of the Nutritional Status, Homocysteine, and CoQ10 of Bank Staff

BACKGROUND

This study aimed to evaluate age-specific variations in the blood levels of micronutrients, homocysteine, and CoQ10, along with physical activity (PA) patterns, among 123 Austrian adult bankers in operational and frontline roles (mean age: 43 years; 50% female).

METHODS

Blood analysis was conducted to assess micronutrients and the serum concentrations of homocysteine and CoQ10. The micronutrient values in whole blood were compared to sex-specific reference ranges and categorized as below, within, or above them. The Global Physical Activity Questionnaire was utilized to assess PA patterns. Participants were classified as young adults (18-34 years), middle-aged adults (35-49 years), and older adults (50-64 years).

RESULTS

Significant age-based differences were found in participants' mean homocysteine levels (p = 0.039) and homocysteine categories (p = 0.034), indicating an increasing prevalence of hyperhomocysteinemia with age. No significant difference between age categories was observed for sex, BMI, diet types, PA levels, sedentary behavior, and CoQ10 (p > 0.05). There was no significant age-based difference in the blood concentrations of most minerals and vitamins (p > 0.05), except for magnesium among females (p = 0.008) and copper among males (p = 0.042).

CONCLUSION

The findings offer initial evidence of the age-related differences in the health status of adult bankers, providing insights for customized approaches to occupational health that support the importance of metabolic health and overall well-being across adulthood.

Association between homocysteine and coronary artery disease-trend over time and across the regions: a systematic review and meta-analysis

BACKGROUND

The association of homocysteine with coronary artery disease (CAD) has been explored previously with mixed findings. The present Systematic Review and Meta-Analysis (SRMA) has assessed the pooled estimate of association between homocysteine (Hcy) and CAD, and its variation over the period and geography.

METHODS

Systematic literature search was done in PubMed, Scopus and Cochrane to identify the observational studies that have reported mean Hcy among cases (CAD) and control. The SRMA was registered in PROSPERO (ID-CRD42023387675).

RESULTS

Pooled standardized mean difference (SMD) of Hcy levels between the cases and controls was 0.73 (95% CI 0.55-0.91) from 59 studies. Heterogeneity was high (I2 94%). The highest SMD was found among the Asian studies (0.85 [95% CI 0.60-1.10]), while the European studies reported the lowest SMD between the cases and controls (0.32 [95% CI 0.18-0.46]). Meta-regression revealed that the strength of association was increasing over the years (Beta = 0.0227, p = 0.048).

CONCLUSIONS

Higher homocysteine levels might have a significant association with coronary artery diseases, but the certainty of evidence was rated low, owing to the observational nature of the studies, high heterogeneity, and publication bias. Within the population groups, Asian and African populations showed a greater strength of association than their European and American counterparts, and it also increased over the years.

Chicken meal is not an appropriate reference protein for estimating protein quality of ingredients used in extruded diets intended for dogs

The indicator amino acid oxidation (IAAO) method has been used to determine metabolic availability (MA) of amino acids in feedstuffs for pigs, humans, and preliminarily for cats. Peas are a commonly used protein source in grain-free extruded dog diets. However, peas have a poor sulfur amino acid (AA) ratio (methionine [Met]:cysteine) with Met being the first limiting AA. Furthermore, little is known about the MA of Met in peas fed to dogs. Therefore, our objective was to compare the MA of Met in peas to chicken meal (CM), as a gold-standard reference protein. The study was done as a replicated 5 × 5 complete Latin square design. Ten neutered male mixed-breed dogs (1.5 years old; 26.0 kg ± 2.4 kg body weight; BW) fed to maintain ideal BW received all dietary treatments: BAS: lamb-based diet (deboned lamb and lamb meal) providing Met at 50% of its requirement (0.27 g/100g dry matter [DM]), CHK: CM and lamb-based diet, and PEA: ground dried pea and lamb-based diet both providing Met at 68% of its requirement (0.35 and 0.37 g/100g DM, respectively). Two other treatments were created by blending BAS with PEA (BAP) and the BAS with CHK (BAC) to create diets with Met at 59% of requirement (0.32 and 0.31 g/100g DM, respectively). This resulted in three graded levels of Met for both CM and peas to allow for a slope-ratio assay approach to quantify MA with the BAS diet as the common first point. All other AAs were provided to meet at least 120% of the AAFCO recommendations for adult dogs. The BAS diet, with supplemental DL-Met, was fed for a 2-wk wash-in period. After 2 d of diet adaptation IAAO was performed. Dogs were fed 13 small meals where meal 6 contained a priming dose (9.4 mg/kg BW) of L-[1-13C]-phenylalanine (Phe; 99%) as well as a constant dose (2.4 mg/kg BW) in meals 6-13. Breath samples were collected and enrichment of 13CO2 was measured using isotope-ratio mass spectrometry to calculate the rate of Phe oxidation (F13CO2 umol/kg BW/h). Oxidation was analyzed via SAS using PROC GLIMMIX with dog and period as random effects, and diet, %Met, and their interaction as fixed effects. Unexpectedly, the slope of Phe oxidation, in response to increasing Met intake, from CM was 31% of that of peas, indicating a lower MA for Met in CM as compared to peas. This finding may be due to damage of AAs during rendering. At this time, CM in extruded diets is not an acceptable reference protein to determine MA of AAs in dogs, and the MA of Met from peas cannot be confidently assessed.

The Association of Physical Activity Level with Micronutrient and Health Status of Austrian Bank Employees

BACKGROUND

Favorable health benefits of an active lifestyle have been clearly documented within the context of occupational health. However, a knowledge gap exists regarding the monitoring and comparison of micronutrient status across varying levels of physical activity (PA). This study aimed to investigate the association of PA level with micronutrient status and the associated health biomarkers among a cohort of Austrian bank employees.

METHODS

Using a cross-sectional design, this study involved the participation of bank employees (n = 123; average age: 43 years; 49% males) from the federal state of Tyrol, located in the western part of Austria. To assess PA levels and sedentary behavior, the Global Physical Activity Questionnaire (GPAQ; developed by the WHO) was administered. Accordingly, participants were categorized into three groups: low PA, moderate PA, and high PA. Participants' blood samples were obtained to measure blood levels of micronutrients, homocysteine, and CoQ10. The values of vitamins and minerals in whole-blood were compared to sex-specific reference ranges and grouped into three categories: below, within, or exceeding the reference range.

RESULTS

The prevalence of a high PA level was 61%, while 18% of participants had a low PA level. Overweight/obesity was significantly less prevalent among participants with high PA levels (22%) compared to those with moderate (50%) and low (50%) PA levels (p = 0.045). No significant differences between PA levels were found for sex, age, diet type, homocysteine, or CoQ10 markers (p > 0.05). There was no significant PA-based difference in blood concentrations of most vitamins and minerals (p > 0.05), except for vitamin D (p = 0.001) among females, as well as selenium (p = 0.040) and vitamin B12 (p = 0.048) among males.

CONCLUSION

The present findings offer initial insights into the link between PA behaviors, micronutrient status, and health, highlighting potential implications in occupational health and lifestyle, specifically in developing tailored approaches based on PA levels.

Sensitively detecting endogenous homocysteine in human serum and cardiomyocytes with a specific fluorescent probe

The elevated level of homocysteine (Hcy) in circulating blood is generally regarded as a risk factor for a variety of diseases including acute myocardial infarction (AMI), but there is no clear answer to whether circulating Hcy can be used for AMI diagnosis. To address it, here we have designed a tetraazacycle-based fluorescent probe for sensitive detection of endogenous Hcy in AMI patients' serum and cardiomyocytes, showing a perfect selectivity over other biothiols (e.g. Cys and GSH). It mainly relies on the formation of a stable six-membered ring structure when this probe responds to Hcy, which is accompanied by a weakening of photoinduced electron transfer (PET) that induces a sharp increase in the fluorescence emission. In this way, Hcy can be probed in biofluids with high sensitivity. We then employed this fluorescent sensor to statistically analyze the levels of Hcy in human circulating blood, indicating a big difference between AMI patients and the healthy participants. To tell whether such a difference is applicable to AMI diagnosis, we further compare the expression levels of Hcy in cardiomyocytes and other tissue cells. It reveals a lower level of endogenous Hcy in cardiomyocytes, implying no direct relationship between the elevated Hcy and cardiomyocyte damage. This observation suggests that Hcy in circulating blood cannot be utilized as a potential biomarker for AMI diagnosis, although it is proven as a risk factor for this disease.

Causal relationship between blood metabolites and risk of five infections: a Mendelian randomization study

OBJECTIVE

Infectious diseases continue to pose a significant threat in the field of global public health, and our understanding of their metabolic pathogenesis remains limited. However, the advent of genome-wide association studies (GWAS) offers an unprecedented opportunity to unravel the relationship between metabolites and infections.

METHODS

Univariable and multivariable Mendelian randomization (MR) was commandeered to elucidate the causal relationship between blood metabolism and five high-frequency infection phenotypes: sepsis, pneumonia, upper respiratory tract infections (URTI), urinary tract infections (UTI), and skin and subcutaneous tissue infection (SSTI). GWAS data for infections were derived from UK Biobank and the FinnGen consortium. The primary analysis was conducted using the inverse variance weighted method on the UK Biobank data, along with a series of sensitivity analyses. Subsequently, replication and meta-analysis were performed on the FinnGen consortium data.

RESULTS

After primary analysis and a series of sensitivity analyses, 17 metabolites were identified from UK Biobank that have a causal relationship with five infections. Upon joint analysis with the FinGen cohort, 7 of these metabolites demonstrated consistent associations. Subsequently, we conducted a multivariable Mendelian randomization analysis to confirm the independent effects of these metabolites. Among known metabolites, genetically predicted 1-stearoylglycerol (1-SG) (odds ratio [OR] = 0.561, 95% confidence interval [CI]: 0.403-0.780, P < 0.001) and 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (CMPF) (OR = 0.780, 95%CI: 0.689-0.883, P < 0.001) was causatively associated with a lower risk of sepsis, and genetically predicted phenylacetate (PA) (OR = 1.426, 95%CI: 1.152-1.765, P = 0.001) and cysteine (OR = 1.522, 95%CI: 1.170-1.980, P = 0.002) were associated with an increased risk of UTI. Ursodeoxycholate (UDCA) (OR = 0.906, 95%CI: 0.829-0.990, P = 0.029) is a protective factor against pneumonia. Two unknown metabolites, X-12407 (OR = 1.294, 95%CI: 1.131-1.481, P < 0.001), and X-12847 (OR = 1.344, 95%CI: 1.152-1.568, P < 0.001), were also identified as independent risk factors for sepsis.

CONCLUSIONS

In this MR study, we demonstrated a causal relationship between blood metabolites and the risk of developing sepsis, pneumonia, and UTI. However, there was no evidence of a causal connection between blood metabolites and the risk of URTI or SSTI, indicating a need for larger-scale studies to further investigate susceptibility to certain infection phenotypes.

Association of Long-term Exposure to Air Pollution and Dementia Risk: The Role of Homocysteine, Methionine, and Cardiovascular Burden

BACKGROUND AND OBJECTIVES

Growing evidence links air pollution with dementia risk, but the biological mechanisms are largely unknown. We investigated the role played by homocysteine (tHcy) and methionine in this association and explored whether this could be explained by cardiovascular diseases (CVDs).

METHODS

Data were extracted from the ongoing Swedish National study on Aging and Care in Kungsholmen (SNAC-K), a longitudinal population-based study. At baseline, 2,512 dementia-free participants were examined up to 2013 (mean follow-up: 5.18 ± 2.96 years). Two air pollutants (particulate matter ≤2.5 μm [PM2.5] and nitrogen oxides [NOx]) were assessed yearly from 1990 until 2013 using dispersion models at residential addresses. The hazard ratio of dementia over air pollution levels was estimated using Cox models adjusted for age, sex, education, smoking, socioeconomic status, physical activity, retirement age, creatinine, year of assessment, and the use of supplements. The total effect of air pollutants on dementia was decomposed into 4 pathways involving tHcy/methionine: (1) direct effect; (2) indirect effect (mediation); (3) effect due to interaction; and (4) effect due to both mediation and interaction. To test whether the association was independent from CVDs (ischemic heart disease, atrial fibrillation, heart failure, and stroke), we repeated the analyses excluding those individuals who developed CVDs.

RESULTS

The mean age of the study participants was 73.4 years (SD: 10.4), and 62.1% were female individuals. During an average period of 5 years (mean: 5.18; SD: 2.96 years), 376 cases with incident dementia were identified. There was a 70% increased hazard of dementia per unit increase of PM2.5 during the 5 years before baseline (hazard ratio [HR]: 1.71; 95% CI 1.33-2.09). Overall, 50% (51.6%; 95% CI 9.0-94.1) of the total effect of PM2.5 on dementia was due to mediation of tHcy (6.6%; 95% CI 1.6-11.6) and/or interaction (47.8%; 95% CI 4.9-91.7) with tHcy and 48.4% (p = 0.03) to the direct effect of PM2.5 on dementia. High levels of methionine reduced the dementia hazard linked to PM2.5 by 31% (HR: 0.69; 95% CI 0.56-0.85) with 24.8% attributable to the interaction with methionine and 25.9% (p = 0.001) to the direct effect of PM2.5. No mediation effect was found through methionine. Attenuated results were obtained for NOx. Findings for tHcy were attenuated after excluding those who developed CVDs, while remained similar for methionine.

DISCUSSION

High levels of homocysteine enhanced the dementia risk attributed to air pollution, while high methionine concentrations reduced this risk. The impact of homocysteine on cardiovascular conditions partly explains this association. Alternative pathways other than cardiovascular mechanisms may be at play between methionine and dementia.

Visual Evoked Potentials in Patients With Vitamin B12 Deficiency

PURPOSE

The aim of this study was to investigate the subclinical involvement of the optic nerve in asymptomatic patients with vitamin B12 deficiency using visual evoked potentials.

METHODS

This study included 40 asymptomatic patients diagnosed with vitamin B12 deficiency (considered as serum levels below 150 pg/mL) and a control group of 40 healthy individuals. All participants underwent a visual evoked potential examination. Routine screening for homocysteine was performed for patients with vitamin B12 deficiency. The levels of vitamin B12 and homocysteine and the presence of megaloblastic anemia were analyzed statistically compared with P100, N75, and N135 latencies and amplitudes.

RESULTS

The mean vitamin B12 level was 96 pg/mL in the patient group and 374 pg/mL in the control group. In the patient group, 24 (60%) patients had hyperhomocysteinemia and 8 (20%) patients had megaloblastic anemia. The P100 wave latency of patients with vitamin B12 deficiency was significantly prolonged compared with the control group ( P < 0.01). There was no significant difference in the P100 amplitude between the patient group and the control group. P100 latencies were significantly longer in patients with hyperhomocysteinemia ( P = 0.002).

CONCLUSIONS

Our study showed that patients with vitamin B12 deficiency may have visual evoked potential abnormalities without visual symptoms or examination findings. In addition, high homocysteine levels led to a prolonged P100 latency in the patient group independent of vitamin B12 levels.

Serum 5-Methyltetrahydrofolate Status Is Associated with One-Carbon Metabolism-Related Metabolite Concentrations and Enzyme Activity Indicators in Young Women

Maintaining optimal one-carbon metabolism (OCM) is essential for health and pregnancy. In this cross-sectional study, folate status was assessed based on 5-methyltetrahydrofolate (5-MTHF) levels, and the association between 5-MTHF and OCM-related metabolites was investigated in 227 female Japanese university students aged 18-25 years. The participants were divided into high and low 5-MTHF groups based on their folate status. Serum samples of the participants were collected while they were fasting, and 18 OCM-related metabolites were measured using stable-isotope dilution liquid chromatography-electrospray tandem mass spectrometry. The association between serum 5-MTHF and OCM-related metabolite concentrations was assessed using Spearman's rank correlation coefficient. Serum 5-MTHF concentrations were negatively correlated with total homocysteine (tHcy) concentrations and positively correlated with S-adenosylmethionine (SAM) and total cysteine (tCys) concentrations. Serum 5-MTHF concentrations demonstrated a stronger negative correlation with tHcy/tCys than with tHcy alone. The negative correlation between betaine and tHcy concentrations was stronger in the low 5-MTHF group than in the high 5-MTHF group. The 5-MTHF status could be linked to Hcy flux into the transsulfuration pathway via SAM. Therefore, the tHcy/tCys ratio may be a more sensitive indicator of the 5-MTHF status than tHcy alone. Furthermore, a low 5-MTHF status can enhance Hcy metabolism via betaine.

Bioimaging of glutathione variation for early diagnosis of hepatocellular carcinoma using a liver-targeting ratiometric near-infrared fluorescent probe

Reliable biomarkers are crucial for early diagnosis of diseases and precise therapy. Biological thiols (represented by glutathione, GSH) play vital roles in the antioxidant defense system for maintaining intracellular redox homeostasis in organisms. However, the aberrant variation in the cellular concentration of GSH correlates with diverse diseases including cancer. Here, a ratiometric near-infrared fluorescent probe CyO-Disu is constructed for the specific sensing of GSH variation in live cells and mice models of hepatic carcinoma (HCC). CyO-Disu features three key elements, a response moiety of bis(2-hydroxyethyl) disulfide, a near-infrared fluorescence signal transducer of heptamethine ketone cyanine, and a targeting moiety of D-galactose. By virtue of its liver-targeting capability, CyO-Disu was utilized for evaluating GSH fluctuations in primary and metastatic hepatoma living cells. To evaluate the efficacy of CyO-Disuin vivo, orthotopic HCC and pulmonary metastatic hepatoma mice models were employed for GSH imaging using two-dimensional and three-dimensional fluorescence molecular tomographic imaging systems. The bioimaging results offered direct evidence that GSH displayed varied concentrations during the progression of HCC. Therefore, the as-synthesized probe CyO-Disu could serve as a potential powerful tool for the early diagnosis and precise treatment of HCC using GSH as a reliable biomarker.

Homocysteine-a retrospective and prospective appraisal

The biologically important amino acid homocysteine links sulfur, methionine, and one-carbon metabolism. This review describes its initial discovery, the identification of the clinical condition of "homocystinuria" and the recognition of its close relationship to folate and vitamin B12 metabolism. It discusses the history behind its current association with diverse diseases including neural tube defects, cardio- and cerebrovascular disease and, more recently, dementia and Alzheimer's Disease. It also explores current controversies and considers potential future research directions. It is intended to give a general overview of homocysteine in relation to health and disease.

A Label-Free Electrochemical Biosensor for Homocysteine Detection Using Molecularly Imprinted Polymer and Nanocomposite-Modified Electrodes

An essential biomarker for the early detection of cardiovascular diseases is serum homocysteine (Hcy). In this study, a molecularly imprinted polymer (MIP) and nanocomposite were used to create a label-free electrochemical biosensor for reliable Hcy detection. A novel Hcy-specific MIP (Hcy-MIP) was synthesized using methacrylic acid (MAA) in the presence of trimethylolpropane trimethacrylate (TRIM). The Hcy-MIP biosensor was fabricated by overlaying the mixture of Hcy-MIP and the carbon nanotube/chitosan/ionic liquid compound (CNT/CS/IL) nanocomposite on the surface of a screen-printed carbon electrode (SPCE). It showed high sensitivity, with a linear response of 5.0 to 150 µM (R² of 0.9753) and with a limit of detection (LOD) at 1.2 µM. It demonstrated low cross-reactivity with ascorbic acid, cysteine, and methionine. Recoveries of 91.10-95.83% were achieved when the Hcy-MIP biosensor was used for Hcy at 50-150 µM concentrations. The repeatability and reproducibility of the biosensor at the Hcy concentrations of 5.0 and 150 µM were very good, with coefficients of variation at 2.27-3.50% and 3.42-4.22%, respectively. This novel biosensor offers a new and effective method for Hcy assay compared with the chemiluminescent microparticle immunoassay at the correlation coefficient (R²) of 0.9946.

Homocysteine Levels in Severe OSA Patients Before and After TORS-OSA Surgery

OBJECTIVE

The increased risk of cardiovascular diseases owing to a high level of serum homocysteine has been widely reported. Literature has demonstrated that patients with obstructive sleep apnea/hypopnea syndrome (OSA) had a higher homocysteine level than control group. This study aimed to investigate the alteration of serum homocysteine levels in severe OSA patients receiving transoral robotic surgery (TORS).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary academic medical center.

METHODS

Data of polysomnography (PSG) and serum homocysteine levels before and at least 3 months after the surgery were collected and analyzed via paired t tests. A subgroup analysis based on the preoperative homocysteine level (≥15 mcmol/L, as hyperhomocysteinemia group) was conducted to compare the intergroup differences of homocysteine decrease. Pearson's correlation was used to survey the relationships between the changes of major PSG parameters and the levels of homocysteine decrease at baseline and after TORS-OSA surgery.

RESULTS

Two hundred sixty-one patients with severe OSA were enrolled. There were significant improvements in major PSG parameters after TORS-OSA surgery. Homocysteine levels significantly decreased from 12.1 ± 3.9 to 11.4 ± 3.7 mcmol/L (difference = -0.7 ± 2.8 mcmol/L, p = .001) postoperatively, which was shown in the hyperhomocysteinemia group (difference = -2.9 ± 4.7 mcmol/L, p = .007) to a greater extent. Pearson's correlation revealed that ΔODI (oxygen desaturation index/h) was the predominant estimate with a positive association with Δhomocysteine (r = 0.525, p = .012).

CONCLUSION

TORS-OSA surgery could decrease homocysteine levels in OSA patients. The effects were more relevant in severe OSA patients with abnormal preoperative homocysteine levels.

Coumarin-Based Fluorescence Probe for Differentiated Detection of Biothiols and Its Bioimaging in Cells

In this work, a coumarin derivative, SWJT-14, was synthesized as a fluorescence probe to distinguish cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in aqueous solutions. The detection limit of Cys, Hcy and GSH for the probe was 0.02 μM, 0.42 μM and 0.92 μM, respectively, which was lower than biothiols in cells. The probe reacted with biothiols to generate different products with different conjugated structures. Additionally, it could distinguish Cys, Hcy and GSH using fluorescence and UV-Vis spectra. The detection mechanism was confirmed by MS. SWJT-14 was successfully used in cellular experiments and detected both endogenous and exogenous biothiols.

Long-Term Intake of Folate, Vitamin B6, and Vitamin B12 and the Incidence of Parkinson's Disease in a Sample of U.S. Women and Men

BACKGROUND

Folate and vitamins B6 and B12 have been proposed as protective against the development of Parkinson's disease (PD). Two prior longitudinal studies were inconclusive.

OBJECTIVE

The aim was to examine the association of long-term intake of folate, vitamin B6, and vitamin B12 with the incidence of PD.

METHODS

The study population comprised 80,965 women (Nurses' Health Study, 1984-2016) and 48,837 men (Health Professionals Follow-up Study, 1986-2016) followed prospectively for the development of PD. Intake of B vitamins was measured at baseline and every 4 years thereafter using food frequency questionnaires. We estimated the hazard ratio (HR) and 95% confidence interval (CI) of PD based on quintiles of cumulative average intake adjusting for potential confounders. Secondary analyses considered different lagged exposure periods as well as baseline and recent intakes.

RESULTS

In separate analyses of cumulative average intake, total folate, B6, and B12 were not associated with the risk of PD. Results from 8-, 12-, and 16-year lag analyses were consistent with these findings. Results for baseline intake of folate and B6 also pointed toward a null association. In contrast, a lower PD risk was observed among individuals with higher baseline total intake of B12 (pooled HR top vs. bottom quintile: 0.80; 95% CI: 0.67-0.95; P-trend = 0.01); results from 20-year lag analyses were consistent with this finding.

CONCLUSIONS

Our results do not support the hypothesis that a higher intake of folate or vitamin B6 would reduce PD risk in this population. Our results provide moderate support for a possible protective effect of vitamin B12 on the development of PD. © 2023 International Parkinson and Movement Disorder Society.

Plasma Homocysteine, Folic Acid and Vitamin B12 in Abruptio Placentae: A Cross-Sectional Study of Their Role and Feto-Maternal Outcome

Background Out of the many causes of abruptio placentae, the micronutrient association with its occurrence and severity has not been researched extensively till now. We aim to measure the serum levels of homocysteine, folic acid and vitamin B12 in patients with abruptio placentae in the third trimester of pregnancy and compare the levels with those without the complication. We also propose to compare the feto-maternal outcome between the groups. Methods The cross-sectional study was undertaken in 50 pregnant women with abruption before or during delivery and 50 controls with uncomplicated pregnancy over 28 weeks of gestation. Serum levels of homocysteine, folic acid, and vitamin B12 were determined and feto-maternal outcome was compared between the groups Results Mean age of the cases and controls are 26.82 ± 5.5 and 28.82 ± 4.88 years respectively. Obstetric characteristics have significant difference between the groups in terms of gravidity, mode of delivery, timing of delivery, proportion of stillbirths and blood transfusion. The mean concentration of homocysteine and vitamin B12 between the groups also have a significant difference . The serum level of homocysteine is significantly correlated with serum vitamin B12 level (Pearson correlation= -0.601, P=0.000). However, folic acid concentration between the groups remains comparable. Conclusion Hence we conclude that vitamin B12 and homocysteine are significant determinants of abruptio placentae in pregnant women. Supplementation with the vitamin in the high-risk Indian population can avert a number of obstetric complications occurring due to raised homocysteine.

Cystathionine Beta-Synthase Deficiency: Three Consecutive Cases Detected in 40 Days by Newborn Screening in Emilia Romagna (Italy) and a Comprehensive Review of the Literature

Cysthiatonine beta-synthase (CBS) deficiency (CBSD) is an autosomal recessive rare disorder caused by variations on CBS that leads to impaired conversion of homocysteine (Hcy) to cystathionine. Marked hyperhomocysteinemia is the hallmark of the disease. The administration of pyridoxine, the natural cofactor of CBS, may reduce total plasma Hcy. Patient phenotype is classified on pyridoxine responsivity in two groups: pyridoxine-responsive and non-responsive patients. Ectopia lentis, bone deformities, developmental delay, and thromboembolism are the classic signs and symptoms of the disease. Early diagnosis and treatment impact patients' natural history. Therapy aims to lower promptly and maintain Hcy concentrations below 100 μmol/L. Depending on the patient's phenotype, the treatment goals could be obtained by the administration of pyridoxine and/or betaine associated with a methionine-restricted diet. CBSD could be diagnosed in the early days of life by expanded newborn screening (ENS), however, the risk of false negative results is not negligible. In Emilia-Romagna (Italy), during the first 10 years of screening experience, only three cases of CBSD identified have been diagnosed, all in the last two years (incidence 1:118,000 live births). We present the cases and a comprehensive review of the literature to emphasize the role of ENS for early diagnosis of CBSD and its potential pitfalls, reiterating the need for a more effective method to screen for CBSD.

Folic acid incorporated nitrogen-doped carbon dots as a turn-on fluorescence probe for homocysteine detection

This study describes the development of a low-cost fluorescence assay for detecting homocysteine (Hcy) without the interference of cysteine and glutathione using carbon quantum dots. Herein nitrogen-doped carbon quantum dots (NCDs) were synthesized from citric acid as the carbon source and urea as the dopant using a one-pot microwave-assisted method. The obtained NCDs were incorporated with folic acid (FA) by the direct ex situ addition method and were used as a fluorescence probe to detect Hcy. The probe exhibited a fluorescence turn-on response with increased Hcy concentration up to 50 μM with a limit of detection of 2.276 μM. The point of care detection of Hcy using the probe was also tested with a paper-based assay strip.

Proton pump inhibitor use and its effect on vitamin B12 and homocysteine levels among men and women: A large cross-sectional study

BACKGROUND

Previous studies have demonstrated an association between proton pump inhibitors (PPI) use and vitamin B12 deficiency. However, data regarding PPI use and elevated serum homocysteine level, an important marker of vitamin B12 deficiency, are scant.

METHODS

Data were collected from medical records of subjects examined at a screening center in Israel. Cross sectional analysis was conducted on 25,953 subjects. Levels of vitamin B12 and homocysteine were compared between subjects who consumed PPI medications and those who did not.

RESULTS

The mean age of the study population was 45 years and 33% were females. Subjects who received PPI medications had a minor higher vitamin B12 levels (320 pmol/L vs 300 pmol/L, p=0.024). Levels of vitamin B12 remained higher in females receiving PPI medications after performing a stratified analysis according to subjects' gender. Homocysteine levels were higher in subjects receiving PPI medications as compared to those who did not (12.0 μmol/L vs 11.6 0 μmol/L, p<0.001). Levels remained higher in female subjects after performing a stratified analysis according to subjects' sex. There was no statistically significant difference in the prevalence of vitamin B12 deficiency (according to two cutoffs: vitamin B12≤200 or ≤140 pmol/L) as well as the prevalence of hyperhomocysteinemia (defined as homocysteine >15.0 μmol/L) between the two groups.

CONCLUSIONS

According to our study, no association was found between PPI medication use and vitamin B12 deficiency or hyperhomocysteinemia. Patients receiving PPI medications had slightly higher levels of vitamin B12 and homocysteine, however these differences were too small to have any clinical relevance.

A 2-Year Randomized Controlled Trial With Low-Dose B-Vitamin Supplementation Shows Benefits on Bone Mineral Density in Adults With Lower B12 Status

Folate, vitamins B12, B6, and riboflavin are required for one-carbon metabolism and may affect bone health, but no previous randomized trial has investigated all four nutrients in this context. We investigated the effect of low-dose B-vitamins for 2 years on bone mineral density (BMD) in a dual-centered, 2-year randomized controlled trial (RCT) in adults aged ≥50 years. Eligible participants not consuming B-vitamin supplements or fortified foods >4 times weekly were randomized to receive daily either combined folic acid (200 μg), vitamin B12 (10 μg), vitamin B6 (10 mg), and riboflavin (5 mg), or "active" placebo, whereby both the intervention and placebo groups received vitamin D (10 μg). BMD was assessed before and after intervention using dual-energy X-ray absorptiometry (DXA) scanning of the total hip, femoral neck, and lumbar spine (L1 to L4). Of 205 eligible participants randomized, 167 completed the trial in full. B-vitamin intervention resulted in increases in serum folate (p < 0.001), serum B12 (p < 0.001), and plasma pyridoxal-5-phosphate (p < 0.001) and decreases in functional biomarkers of B-vitamin status, erythrocyte glutathione reductase activation coefficient (p < 0.001), serum methylmalonic acid (MMA; p < 0.001), and serum total homocysteine (p < 0.001). B-vitamin intervention had no overall effect on BMD, which declined in both treatment groups by approximately 1% (ranging from -0.7% to -1.4%). However, in participants with lower baseline B12 status (serum B12 <246 pmol/L or MMA ≥0.22 μmol/L), B-vitamin intervention reduced the 2-year BMD decline versus placebo: adjusted mean (95% confidence interval [CI]) change of -0.003 (-0.008, 0.002) versus -0.015 (-0.021, -0.010) g/cm² at the total hip and -0.004 (-0.010, 0.001) versus -0.013 (-0.018, -0.007) g/cm² at the femoral neck. In conclusion, the findings indicate that although low-dose B-vitamin intervention for 2 years had no overall effect on BMD, improving B-vitamin status appears to have specific benefits for bone health in adults with lower B12 status. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Resolving Geroplasticity to the Balance of Rejuvenins and Geriatrins

According to the cell centric hypotheses, the deficits that drive aging occur within cells by age dependent progressive damage to organelles, telomeres, biologic signaling pathways, bioinformational molecules, and by exhaustion of stem cells. Here, we amend these hypotheses and propose an eco-centric model for geroplasticity (aging plasticity including aging reversal). According to this model, youth and aging are plastic and require constant maintenance, and, respectively, engage a host of endogenous rejuvenating (rejuvenins) and gero-inducing [geriatrin] factors. Aging in this model is akin to atrophy that occurs as a result of damage or withdrawal of trophic factors. Rejuvenins maintain and geriatrins adversely impact cellular homeostasis, cell fitness, and proliferation, stem cell pools, damage response and repair. Rejuvenins reduce and geriatrins increase the age-related disorders, inflammatory signaling, and senescence and adjust the epigenetic clock. When viewed through this perspective, aging can be successfully reversed by supplementation with rejuvenins and by reducing the levels of geriatrins.

The effect of vitamin B supplementation on neuronal injury in people living with HIV: a randomized controlled trial

Effective antiretroviral therapy has radically changed the course of the HIV pandemic. However, despite efficient therapy, milder forms of neurocognitive symptoms are still present in people living with HIV. Plasma homocysteine is a marker of vitamin B deficiency and has been associated with cognitive impairment. People living with HIV have higher homocysteine concentrations than HIV-negative controls, and we have previously found an association between plasma homocysteine concentration and CSF concentration of neurofilament light protein, a sensitive marker for ongoing neuronal injury in HIV. This prompted us to perform this randomized controlled trial, to evaluate the effect of vitamin B supplementation on neuronal injury in a cohort of people living with HIV on stable antiretroviral therapy. At the Department of Infectious Diseases at Sahlgrenska University Hospital in Gothenburg, Sweden, 124 virally suppressed people living with HIV were screened to determine eligibility for this study. Sixty-one fulfilled the inclusion criteria by having plasma homocysteine levels at or above 12 μmol/l. They were randomized (1:1) to either active treatment (with cyanocobalamin 0.5 mg, folic acid 0.8 mg and pyridoxine 3.0 mg) q.d. or to a control arm with a cross over to active treatment after 12 months. Cognitive function was measured repeatedly during the trial, which ran for 24 months. We found a significant correlation between plasma neurofilament light protein and plasma homocysteine at screening (n = 124, r = 0.35, P < 0.0001). Plasma homocysteine levels decreased by 35% from a geometric mean of 15.7 μmol/l (95% confidence interval 14.7–16.7) to 10.3 μmol/l (95% confidence interval 9.3–11.3) in the active treatment arm between baseline and Month 12. No significant change was detected in the control arm during the same time period [geometric mean 15.2 (95% confidence interval 14.3–16.2) versus geometric mean 16.5 μmol/l (95% confidence interval 14.7–18.6)]. A significant difference in change in plasma homocysteine levels was seen between arms at 12 months [−40% (95% confidence interval −48 to −30%), P < 0.001]. However, no difference between arms was seen in either plasma neurofilament light protein levels [−6.5% (−20 to 9%), P = 0.39], or cognitive measures [−0.08 (−0.33 to 0.17), P = 0.53]. Our results do not support a vitamin B–dependent cause of the correlation between neurofilament light protein and homocysteine. Additional studies are needed to further elucidate this matter.

Homocysteine thiolactone contributes to the prognostic value of fibrin clot structure/function in coronary artery disease

Fibrin clot structure/function contributes to cardiovascular disease. We examined sulfur-containing metabolites as determinants of fibrin clot lysis time (CLT) and maximum absorbance (Absmax) in relation to outcomes in coronary artery disease (CAD) patients. Effects of B-vitamin/folate therapy on CLT and Absmax were studied. Plasma samples were collected from 1,952 CAD patients randomized in a 2 x 2 factorial design to (i) folic acid, vitamins B12, B6; (ii) folic acid, vitamin B12; (iii) vitamin B6; (iv) placebo for 3.8 years in the Western Norway B-Vitamin Intervention Trial. Clot lysis time (CLT) and maximum absorbance (Absmax) were determined using a validated turbidimetric assay. Acute myocardial infarction (AMI) and mortality were assessed during a 7-year follow-up. Data were analyzed using bivariate and multiple regression. Survival free of events was studied using Kaplan Mayer plots. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models. Baseline urinary homocysteine (uHcy)-thiolactone and plasma cysteine (Cys) were significantly associated with CLT while plasma total Hcy was significantly associated with Absmax, independently of fibrinogen, triglycerides, vitamin E, glomerular filtration rate, body mass index, age, sex plasma creatinine, CRP, HDL-C, ApoA1, and previous diseases. B-vitamins/folate did not affect CLT and Absmax. Kaplan-Meier analysis showed associations of increased baseline CLT and Absmax with worse outcomes. In Cox regression analysis, baseline CLT and Absmax (>cutoff) predicted AMI (CLT: HR 1.58, 95% CI 1.10-2.28; P = 0.013. Absmax: HR 3.22, CI 1.19-8.69; P = 0.021) and mortality (CLT: HR 2.54, 95% CI 1.40-4.63; P = 0.002. Absmax: 2.39, 95% CI 1.17-4.92; P = 0.017). After adjustments for other prognostic biomarkers these associations remained significant. Cys and uHcy-thiolactone, but not tHcy, were significant predictors of AMI in Cox regression models that included CLT. Conclusions uHcy-thiolactone and plasma Cys are novel determinants of CLT, an important predictor of adverse CAD outcomes. CLT and Absmax were not affected by B-vitamin/folate therapy, which could account for the lack of efficacy of such therapy in CAD. Trial registration: URL: http://clinicaltrials.gov. Identifier: NCT00354081.

Human ultrarare genetic disorders of sulfur metabolism demonstrate redundancies in H2S homeostasis

Regulation of H₂S homeostasis in humans is poorly understood. Therefore, we assessed the importance of individual enzymes in synthesis and catabolism of H₂S by studying patients with respective genetic defects. We analyzed sulfur compounds (including bioavailable sulfide) in 37 untreated or insufficiently treated patients with seven ultrarare enzyme deficiencies and compared them to 63 controls. Surprisingly, we observed that patients with severe deficiency in cystathionine β-synthase (CBS) or cystathionine γ-lyase (CSE) - the enzymes primarily responsible for H₂S synthesis - exhibited increased and normal levels of bioavailable sulfide, respectively. However, an approximately 21-fold increase of urinary homolanthionine in CBS deficiency strongly suggests that lacking CBS activity is compensated for by an increase in CSE-dependent H₂S synthesis from accumulating homocysteine, which suggests a control of H₂S homeostasis in vivo. In deficiency of sulfide:quinone oxidoreductase - the first enzyme in mitochondrial H₂S oxidation - we found normal H₂S concentrations in a symptomatic patient and his asymptomatic sibling, and elevated levels in an asymptomatic sibling, challenging the requirement for this enzyme in catabolizing H₂S under physiological conditions. Patients with ethylmalonic encephalopathy and sulfite oxidase/molybdenum cofactor deficiencies exhibited massive accumulation of thiosulfate and sulfite with formation of large amounts of S-sulfocysteine and S-sulfohomocysteine, increased renal losses of sulfur compounds and concomitant strong reduction in plasma total cysteine. Our results demonstrate the value of a comprehensive assessment of sulfur compounds in severe disorders of homocysteine/cysteine metabolism and provide evidence for redundancy and compensatory mechanisms in the maintenance of H₂S homeostasis.

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Cystathionine γ-lyase can compensate for decreased H₂S synthesis in cystathionine β-synthase deficiency.

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Sulfide:quinone oxidoreductase deficiency is compatible with normal H₂S plasma levels under non-stressed conditions.

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Persulfide dioxygenase deficiency (ethylmalonic encephalopathy) causes the largest accumulation of H₂S among disorders of sulfur metabolism.

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Excess sulfite forms S-sulfocysteine and S-sulfohomocysteine, and interferes with vitamin B₆ metabolism.

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S-sulfocysteine correlates directly with sulfite and is a stable biomarker of sulfite accumulation.

Role of Extracellular Matrix and Inflammation in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is one of the most dangerous cardiovascular diseases, occurring mainly in men over the age of 55 years. As it is asymptomatic, patients are diagnosed very late, usually when they suffer pain in the abdominal cavity. The late detection of AAA contributes to the high mortality rate. Many environmental, genetic, and molecular factors contribute to the development and subsequent rupture of AAA. Inflammation, apoptosis of smooth muscle cells, and degradation of the extracellular matrix in the AAA wall are believed to be the major molecular processes underlying AAA formation. Until now, no pharmacological treatment has been implemented to prevent the formation of AAA or to cure the disease. Therefore, it is important that patients are diagnosed at a very early stage of the disease. Biomarkers contribute to the assessment of the concentration level, which will help to determine the level and rate of AAA development. The potential biomarkers today include homocysteine, cathepsins, osteopontin, and osteoprotegerin. In this review, we describe the major aspects of molecular processes that take place in the aortic wall during AAA formation. In addition, biomarkers, the monitoring of which will contribute to the prompt diagnosis of AAA patients over the age of 55 years, are described.

Homocystinuria diagnosis and management: it is not all classical

Homocystinuria (HCU) refers to a group of inherited disorders of homocysteine metabolism associated with high blood homocysteine concentration, thromboembolic tendency and neurocognitive symptoms. The most common causes of a high blood homocysteine relate to underlying vitamin B12 or folate deficiency which must be excluded first. Thereafter, an inherited metabolic condition can be considered.The most prevalent inherited disorder of homocysteine metabolism is classical HCU caused by deficiency of the pyridoxine-dependent enzyme, cystathione beta-synthase, which converts homocysteine to cystathionine in the transsulphuration pathway. An alternative route for homocysteine metabolism is its remethylation to methionine by the cobalamin-dependent enzyme, methionine synthase, using the folate derivative, methyltetrahydrofolate, as a methyl donor. Remethylation defects are caused by impaired activity of methionine synthase itself, of an enzyme required to generate its methylcobalamin cofactor from dietary vitamin B12, or of the enzyme methyltetrahydrofolate reductase (MTHFR), which generates the methyl donor.The correct diagnosis can be inferred from additional laboratory investigations including a complete blood count and quantitation of methionine and methylmalonic acid. Methionine is high/normal in HCU and low in the remethylation disorders. In the latter, cobalamin defects are readily distinguished from MTHFR by a coexisting macrocytic anaemia and further delineated by presence or absence of methylmalonic acid in urine or plasma.Lowering homocysteine reverses thromboembolic risk. In HCU, this may be achieved with pyridoxine alone or with betaine as an alternative methyl donor. Some patients additionally follow a methionine-restricted diet. Betaine is the primary treatment for MTHFR and cobalamin disorders are managed with high-dose hydroxocobalamin.

B Vitamin Supplementation Slows Cognitive Decline in Mild Cognitive Impairment Patients with Frontal Lobe Atrophy

BACKGROUND

The effects of B vitamins on mild cognitive impairment (MCI) patients' cognition have been mixed, suggesting the existence of moderating factors.

OBJECTIVE

A post hoc analysis of a negative B vitamin trial was performed to examine the potential modulating effect of regional brain atrophy on the cognitive response to B vitamins in MCI patients.

METHODS

In the 24-month randomized trial, 279 MCI outpatients took 500μ#x03BC;g methylcobalamin and 400μ#x03BC;g folic acid once per day or placebo tablets once per day. Sixty-four aspirin users were excluded from analysis as aspirin use has been found to have significant negative interaction effects. Subjects were followed up at months 12 and 24. The primary cognitive outcome was clinical dementia rating scale sum of boxes (CDR_SOB). In a subgroup of 83 subjects, MRI brain scans were performed at baseline to estimate regional brain atrophy ratios.

RESULTS

Among the trial subjects who had MRI data, B vitamin supplementation had no significant effect on CDR_SOB, despite having significant homocysteine lowering effects. The atrophy ratio of the left frontal lobe significantly moderated the effect of B vitamin supplementation on CDR_SOB, after adjusting for confounders, in that B vitamin supplementation was associated with lower CDR_SOB scores (i.e., better cognitive function) at the 24th month among those patients with above median atrophy ratios, but not among those with lower atrophy ratios, in the left frontal lobe.

CONCLUSION

B vitamins may be more effective in slowing down cognitive decline in MCI patients with atrophy in the left frontal lobe.

Interrelation between homocysteine metabolism and the development of autism spectrum disorder in children

Evidence is emerging that dysregulation of circulating concentrations of homocysteine, an important intermediate in folate and vitamin B12 metabolism, is associated with autism spectrum disorder (ASD), but comprehensive assessments and correlations with disease characteristics have not been reported. Multivariate ordinal regression and restricted cubic spline (RCS) models were used to estimate independent correlations between serum homocysteine, folate, and vitamin B12 levels and clinical outcomes and severity of children with ASD. After adjusting for confounding factors, serum homocysteine levels were significantly higher in children with ASD than in healthy controls (β: 0.370; 95% CI: 0.299~0.441, p < 0.001). Moreover, homocysteine had a good diagnostic ability for distinguishing children with ASD from healthy subjects (AUC: 0.899, p < 0.001). The RCS model indicated a positive and linear association between serum homocysteine and the risk of ASD. The lowest quartile of folate was positively associated with ASD severity (OR: 4.227, 95% CI: 1.022~17.488, p = 0.041) compared to the highest quartile, and serum folate showed a negative and linear association with ASD severity. In addition, decreased concentrations of folate and vitamin B12 were associated with poor adaptive behavior developmental quotients of the Gesell Developmental Schedules (p < 0.05). Overall, an increased homocysteine level was associated with ASD in a linear manner and is thus a novel diagnostic biomarker for ASD. Decreased concentrations of folate and vitamin B12 were associated with poor clinical profiles of children with ASD. These findings suggest that homocysteine-lowering interventions or folate and vitamin B12 supplementation might be a viable treatment strategy for ASD.

The association of MTHFR (rs1801133) with hypertension in an indigenous south African population

Aims: The current study sought to investigate the association between the methylenetetrahydrofolate reductase (MTHFR) variant (rs1801133) and the risk of developing hypertension (HTN) in an indigenous South African population.

Methods: A total of 442 participants (hypertensive, n = 279 and non-hypertensive, n = 163) from the indigenous tribe residing in Mthatha, Eastern Cape (South Africa) were recruited. HTN was defined as a systolic (SBP) and diastolic blood pressure (DBP) of ≥130/80 mmHg following American Heart Association guidelines. The genotyping of MTHFR (rs1801133) was assessed using MassARRAY^® System. Thereafter, the association between rs1801133 in various genetic models and HTN was determined by logistic regression model analysis. Furthermore, the interaction between rs1801133 and selected risk factors on HTN was performed using the open-source multifactor dimensionality reduction (MDR).

Results: The low frequency of the T allele (5%) was also observed when compared with the C allele (95%) in both cases and controls. After adjusting for confounding factors (gender, smoking status, BMI, and blood glucose levels), there were no significant associations were observed between rs1801133 and the risk of HTN in all genetic models: genotypic (OR 0.75, 95% CI 0.29–1.95, p = 0.56), dominant (OR 0.86, 95% CI 0.35–2.16, p = 0.75), co-dominant (OR 1.33, 95% CI 0.51–3.48, p = 0.55) and allelic (OR 0.80, 95% CI 0.49–1.62, p = 0.70) in logistic regression analysis. However, a significant interaction was reported among rs1801133, age, and gender (p < 0.0001) with the risk of HTN.

Conclusion: The present study reports on the lack of association between MTHFR (rs1801133) and the risk of HTN in an indigenous South African tribe. However, an interaction between gender, age, and rs1801133 was observed. Thus, future studies with a large sample size are required to further validate these findings.