Urinary methylmalonic acid levels in patients with acute ischemic stroke

Low concentration of serum vitamin B12 may be a strong predictor of large-artery atherosclerosis stroke: A case-control study

INTRODUCTION

Identifying controllable risk factors for large-artery atherosclerosis (LAA) stroke is crucial due to its significant role as a leading cause of ischemic stroke. We aimed to validate the correlation of serum vitamin B12 with LAA stroke.

METHODS

Inpatients with LAA stroke and healthy controls were retrospectively collected for a case-control study from January 2020 to May 2022. Serum vitamin B12 concentration and other blood indicators, demographic, lifestyle factors and comorbidities were investigated. Logistic regression analysis was used to identify the correlation of serum vitamin B12 concentrations with LAA stroke, meanwhile adjusted for confounding factors.

RESULTS

Patients with LAA stroke had significantly lower serum vitamin B12 concentrations in comparison to those of controls. In the fully adjusted model, vitamin B12 (per 1 interquartile range increase, odds ratio [OR] = 0.84, 95 % confidence interval [CI]: 0.77-0.91), vitamin B12 < 200 pg/mL (OR=7.70, 95 %CI: 2.19-27.03) and vitamin B12 < 300 pg/mL (OR=4.19, 95 %CI: 1.82-9.66) were independently factors for LAA stroke. Furthermore, the optimal cut-off values for vitamin B12 to predict LAA stroke were 305.25 pg/mL (area under the curve [AUC] = 0.71) when unadjusted and 308.25 pg/mL when adjusted for age and sex (AUC=0.68). Lower vitamin B12 concentrations were significantly associated with male sex, smoking, older age, higher neutrophil count, higher creatinine, lower folate and higher total homocysteine.

CONCLUSION

Results indicate that low concentration of serum vitamin B12 may be a strong predictor for the risk of LAA stroke.

The association between methylmalonic acid, a biomarker of mitochondria dysfunction, and phenotypic age acceleration: A population-based study

Phenotypic age acceleration (PAA) is a sensitive marker of biological aging. Circulating methylmalonic acid (MMA) is a novel biomarker of mitochondrial dysfunction and has been associated with age-related disorders. Our study aimed to investigate to what extent circulating MMA was associated with PAA, and whether the association was independent of vitamin B12 status and renal function in the general population. We analyzed cross-sectional data from 13,023 participants across a wide age range (mean age: 38.9 years, range: 12 - 85 years, 51.1% women) from the US National Health and Nutrition Examination Survey (NHANES). PAA was calculated based on the published algorithm. Linear regression models were performed to assess the association between circulating MAA and PAA. Only 31% of the variation in MMA levels was explained by age, sex, race/ethnicity, social economic status, vitamin B12 status, and renal function. Per unit increase in circulating MAA (1.0 nmol/L) was associated with 1.59 years increase in PAA (β = 1.59, 95% CI: 1.17, 2.00, p < 0.001) after adjusting for multiple confounders. Importantly, PAA increased with circulating MMA levels independent of vitamin B12, creatine, and homocysteine levels. The association was more pronounced in subgroups of age ≥ 65 years, women, underweight, vitamin B12 < 400 μmol/L, and homocysteine ≥ 10 μmol/L. The association was much stronger among participants with cardiovascular diseases (CVDs) than without CVDs. In conclusion, our current population-based study showed that mitochondria-derived circulating MMA was associated with increased phenotypic age acceleration in the general population.

Hyperhomocysteinemia and Ischemic Stroke: A Potential Dose-Response Association-A Systematic Review and Meta-analysis

Background and Purpose  Previous studies suggest an association between increased homocysteine (Hcy) and risk of ischemic stroke. Yet, it remains unknown whether a dose-response association exists between Hcy levels and risk of ischemic stroke. Methods  Systematic literature searches were performed in PubMed, Embase, Scopus, and Web of Science. Inclusion criteria were studies investigating ischemic stroke risk in an adult population with measured Hcy levels. We computed odds ratios (ORs) for a 5 µmol/L increase in Hcy levels using a random effects meta-analysis. Results  In total, 108 studies met the inclusion criteria of which 22 were rated as high-quality studies, and 20 studies included a dose-response analysis. Hcy levels were analyzed either as a continuous or categorical variable. The majority of the studies found an increased risk of ischemic stroke when comparing the highest-to-lowest Hcy strata. A graded association was observed over the Hcy strata, indicating a dose-response association, with the most apparent effect when Hcy levels exceeded approximately 15 µmol/L. No studies explored a potential nonlinear association between Hcy levels and ischemic stroke. Six studies were included in a meta-analysis, showing an OR of 1.43 (95% confidence interval [CI]: 1.28-1.61) per 5 µmol/L increase in Hcy levels. Conclusion  This review and meta-analysis indicate a dose-response association between Hcy levels and ischemic stroke. An evident increase in effect measures was observed when Hcy levels exceeded 15 µmol/L, indicating a nonlinear association between ischemic stroke and Hcy levels. This nonlinear association warrants further study. This study is registered with clinical trial ( https://www.crd.york.ac.uk/prospero/ ; unique identifier: CRD42019130371).

Elevated Urinary Methylmalonic Acid/creatinine ratio and Serum Sterol levels in Patients with Acute Ischemic Stroke

Introduction: Sitosterolemia, defined as phytosterolemia, is a rare autosomal recessive disease characterized by elevated blood sterol levels. Our aim was to investigate serum plant sterols, methylmalonic acid, vitamin B12, oxidized-LDL and homocysteine levels in ischemic and hemorrhagic stroke patients and healthy subjects. Material and Methods: 50 healthy subjects (without a family history of coronary artery disease) and 89 patients hospitalized in the Selcuk University neurology clinic or intensive care unit with a diagnosis of stroke were included in this study. Serum plant sterols, homocysteine and methylmalonic acid, oxidized-LDL, total cholesterol, triglycerides, HDL-Cholesterol and vitamin B12 levels were analyzed by gas chromatography-mass spectrometry, liquid-chromatography tandem mass spectrometry, commercially available ELISA kit, spectrophotometry and chemiluminescence methods, respectively. Results: Urinary methylmalonic acid/creatinine ratio (p< 0.05), serum β-sitosterol levels and β-sitosterol/ cholesterol ratio were significantly higher (p <0.01) in patients compared to the control group. There was a significant positive correlation between the serum OxLDL- methylmalonic acid, serum homocysteine- urinary methylmalonic acid /creatinine ratio, serum methylmalonic acid - Urinary methylmalonic acid (p<0.05), serum homocysteine- urinary methylmalonic acid, urinary methylmalonic acid-methylmalonic acid/creatinine ratio, serum methylmalonic acid- methylmalonic acid/creatinine ratio, serum beta-sitosterol- beta-sitosterol /cholesterol, total cholesterol-HDL, total cholesterol-LDL (p <0.01) levels and negative correlation between vitamin B12- serum methylmalonic acid (p<0.05), cholesterol-stigmasterol/cholesterol, LDL- stigmasterol/cholesterol (p <0.01) levels in the patient group. Conclusion: Our findings presented that the serum sitosterol levels were significantly higher in stroke patients compared to controls.