Vitamin B12 and progression of white matter lesions. A 2-year follow-up study in first-ever lacunar stroke patients

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.

Effects of vitamin B12 deficiency on risk and outcome of ischemic stroke

Ischemic stroke is the most prevalent form of stroke and has a high incidence in older adults, characterized by high morbidity, mortality, disability, and recurrence rate. Vitamin B₁₂ deficiency is prevalent in the elderly and has been reported to be associated with ischemic stroke. The mechanisms maybe include the disorder of methylation metabolism, accumulation of toxic metabolites, immune dysfunction, affecting gut microbial composition and gut-brain immune homeostasis, and toxic stress responses to the brain. Vitamin B₁₂ deficiency may lead to cerebral artery atherosclerosis, change myelination, influence the metabolism and transmission between nerve tissue, and ultimately causes the occurrence and development of ischemic stroke. This paper reviews the correlation between vitamin B₁₂ deficiency and ischemic stroke, looking forward to improving clinicians' understanding and providing new therapeutic directions for ischemic stroke.

Non-Linear Association between Folate/Vitamin B12 Status and Cognitive Function in Older Adults

Although folate and vitamin B12 status have long been implicated in cognitive function, there is no consensus on the threshold of folate and vitamin B12 for assessing their impacts on cognition. The goal of this study was to detail the association between folate and vitamin B12 with cognitive performance. We analyzed cross-sectional data of older adults (≥60 y; n = 2204) from the NHANES (National Health and Nutrition Examination Surveys) cohort from 2011–2014. The restricted cubic spline model was used for describing the associations between serum total folate, RBC folate, 5-methyltetrahydrofolate, and vitamin B12 and the Consortium to Establish a Registry for Alzheimer’s Disease Word Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tests, the Animal Fluency (AF) test, and the Digit Symbol Substitution Test (DSST), respectively. Older adults with a different folate and vitamin B12 status were clustered by artificial intelligence unsupervised learning. The statistically significant non-linear relationships between the markers of folate or vitamin B12 status and cognitive function were found after adjustments for potential confounders. Inverse U-shaped associations between folate/vitamin B12 status and cognitive function were observed, and the estimated breakpoint was described. No statistically significant interaction between vitamin B12 and folate status on cognitive function was observed in the current models. In addition, based on the biochemical examination of these four markers, older adults could be assigned into three clusters representing relatively low, medium, and high folate/vitamin B12 status with significantly different scores on the CERAD-DR and DSST. Low or high folate and vitamin B12 status affected selective domains of cognition, and was associated with suboptimal cognitive test outcomes.

Parkinsonism and cerebrovascular disease

The relationship between cerebrovascular disease and parkinsonism is commonly seen in everyday clinical practice but remains ill-defined and under-recognised with little guidance for the practising neurologist. We attempt to define this association and to illustrate key clinical, radiological and pathological features of the syndrome of Vascular Parkinsonism (VaP). VaP is a major cause of morbidity in the elderly associated with falls, hip fractures and cognitive impairment. Although acute parkinsonism is reported in the context of an acute cerebrovascular event, the vast majority of VaP presents as an insidious syndrome usually in the context of vascular risk factors and radiological evidence of small vessel disease. There may be an anatomic impact on basal ganglia neuronal networks, however the effect of small vessel disease (SVD) on these pathways is not clear. There are now established reporting standards for radiological features of SVD on MRI. White matter hyperintensities and lacunes have been thought to be the representative radiological features of SVD but other features such as the perivascular space are gaining more importance, especially in context of the glymphatic system. It is important to consider VaP in the differential diagnosis of Parkinson disease (PD) and in these situations, neuroimaging may offer diagnostic benefit especially in those patients with atypical presentations or refractoriness to levodopa. Proactive management of vascular risk factors, monitoring of bone density and an exercise program may offer easily attainable therapeutic targets in PD and VaP. Levodopa therapy should be considered in patients with VaP, however the dose and effect may be different from use in PD. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Association between Vitamin B12 levels and cognitive function in the elderly Korean population

Vitamin B12 (B12), also known as cobalamin, is a water-soluble vitamin. It is a cofactor in DNA synthesis and is involved in the metabolism of every cell of the human body, including the central nervous system. Those with a deficiency of B12 can present with peripheral neuropathy, pernicious anemia, or a cognitive disorder. Previous studies have revealed that a deficiency of B12 is associated with cognitive decline or Alzheimer disease.The data of 2991 people were evaluated from 2 years of the Korean Frailty and Aging Cohort Study, a nationwide multicenter survey. To assess cognitive function, a short form of the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) was used. Of the CERAD-K tests, we included the Mini-Mental State Examination in the Korean version of the CERAD assessment packet (MMSE-KC), the word list: memory/recall/recognition, digit span (forward, backward), trail making test-A, and the frontal assessment battery. B12 concentrations were classified into clinically relevant categories, insufficient (<350 pg/mL) and sufficient (≥350 pg/mL). A linear regression analysis was used to evaluate the relationship between cognitive function and B12 levels.The mean age of the 2991 participants was 76.4 ± 3.9 years old. Overall, 414 (13.8%) were classified as B12 insufficient, and 2577 (86.2%) as B12 sufficient. The sufficient B12 group performed better in the MMSE-KC, Wordlist: memory, Wordlist: recognition, TMT-A test, digit span, and FAB tests. This was statistically significant (P < .05). However, in the multivariable linear regression analysis, after adjusting for age, sex, education period, marriage, smoking and drinking habits, and comorbidities, the association between the B12 group and cognitive function was not statistically significant.Although our study does not show that B12 insufficiency is a direct risk factor to cognitive decline, B12 levels could be a contributing factor to cognitive function. Our results suggest that cognition was affected by the B12 levels, along with demographic and sociological variables.

B Vitamins and Fatty Acids: What Do They Share with Small Vessel Disease-Related Dementia?

Many studies have been written on vitamin supplementation, fatty acid, and dementia, but results are still under debate, and no definite conclusion has yet been drawn. Nevertheless, a significant amount of lab evidence confirms that vitamins of the B group are tightly related to gene control for endothelium protection, act as antioxidants, play a co-enzymatic role in the most critical biochemical reactions inside the brain, and cooperate with many other elements, such as choline, for the synthesis of polyunsaturated phosphatidylcholine, through S-adenosyl-methionine (SAM) methyl donation. B-vitamins have anti-inflammatory properties and act in protective roles against neurodegenerative mechanisms, for example, through modulation of the glutamate currents and a reduction of the calcium currents. In addition, they also have extraordinary antioxidant properties. However, laboratory data are far from clinical practice. Many studies have tried to apply these results in everyday clinical activity, but results have been discouraging and far from a possible resolution of the associated mysteries, like those represented by Alzheimer's disease (AD) or small vessel disease dementia. Above all, two significant problems emerge from the research: No consensus exists on general diagnostic criteria-MCI or AD? Which diagnostic criteria should be applied for small vessel disease-related dementia? In addition, no general schema exists for determining a possible correct time of implementation to have effective results. Here we present an up-to-date review of the literature on such topics, shedding some light on the possible interaction of vitamins and phosphatidylcholine, and their role in brain metabolism and catabolism. Further studies should take into account all of these questions, with well-designed and world-homogeneous trials.

Subcortical lesions due to cobalamin deficiency: an unusual MRI lesion pattern

We present a 44-year-old male patient with new onset of right focal epilepsy and bilateral hand hypesthesia. Cerebral MRI showed bilateral T2w/DWI hyperintense subcortical lesions in the cingulate gyrus, insula, and amygdala, whereas spinal MRI revealed a cervical posterior column lesion, corresponding to subacute combined degeneration. Laboratory workup revealed a cobalamin deficiency due to type A gastritis, and no evidence of antibodies associated with limbic encephalitis. After sufficient cobalamin substitution, the cerebral and spinal lesions gradually regressed. Our case represents a unique cerebral subcortical MRI lesion pattern in a patient with epilepsy and cobalamin deficiency. Thus, the latter represents an important differential diagnosis for autoimmune encephalitis.

Risk factors of pure leukoaraiosis and the association with preclinical carotid atherosclerosis

BACKGROUND AND AIMS

The risk factors of cerebral large artery disease (carotid atherosclerosis) have been well recognized, but not of small artery disease, especially leukoaraiosis. In this study, we investigated the risk factors of pure leukoaraiosis (without stroke), and the association with preclinical carotid atherosclerosis.

METHODS

Data from 384 subjects with leukoaraiosis and 379 controls with normal cerebral parenchyma were collected at the Beijing Tiantan Hospital from 1 January, 2009 to 31 December, 2015. Entry criteria: 1) age over 40 years; 2) not taking lipid lowering drugs and vitamin B; 3) normal cerebral parenchyma or leukoaraiosis on brain MRI scan; 4) intra- and extra-cranial large artery stenosis less than 50%.

EXCLUSION CRITERIA

1) any brain lesions except cerebral leukoaraiosis; 2) severe systemic diseases. Age, gender, well-known vascular risk factors, serum lipid profile, levels of total homocysteine, vitamin B12, folic acid were analyzed with multivariable logistic regression model.

RESULTS

Age and hypertension, but not serum homocysteine, vitamin B12, folic acid, or serum lipid profile, were independently associated with leukoaraiosis. Furthermore, there was no significant association between pure leukoaraiosis and preclinical carotid atherosclerosis after adjusting for age.

CONCLUSIONS

Only age and hypertension are independently related to pure leukoaraiosis, and there is no association between pure leukoaraiosis and preclinical carotid atherosclerosis.

Vitamin B12

The biosynthesis of B₁₂, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B₁₂, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B₁₂ deficiency. However, there is no sharp cutoff for B₁₂ deficiency; rather, there is a continuous inverse relationship between serum B₁₂ and a variety of undesirable outcomes, including neural tube defects, stroke, and dementia. The brain is particularly vulnerable; in children, inadequate B₁₂ stunts brain and intellectual development. Suboptimal B₁₂ status (serum B₁₂<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in pregnant women and in less-developed countries. Thus, many tens of millions of people in the world may suffer harm from having a poor B₁₂ status. Public health steps are urgently needed to correct this inadequacy.

Serum Vitamin B12, Homocysteine and Methylmalonic Acid Levels in Patients With Parenchymal Neuro-Behçet's Syndrome

Objectives

This study aims to investigate the role of serum levels of vitamin B12 (VitB12), homocysteine (Hcy), and methylmalonic acid (MMA) in the development of parenchymal neuro-Behçet's syndrome (NBS) and to compare them with healthy controls and Behçet's syndrome (BS) patients without NBS.

Patients and methods

Serum VitB12, Hcy, and MMA were measured using enzyme-linked immunosorbent assay in 64 patients (36 males, 28 females; mean age 36±8.3 years; range 20 to 56 years) who met the criteria of the International Study Group for Behçet's Disease and 30 matched healthy controls (17 males, 13 females; mean age 35.76±9.6 years; range 20 to 50 years). The study participants were grouped as BS patients with NBS, BS patients without NBS, and healthy controls.

Results

There was no significant difference between the groups regarding serum VitB12, Hcy, and MMA levels (p>0.05). Serum VitB12 levels were below the lower limit and serum Hcy levels were above the upper limit in all participants. MMA levels were normal in all participants. There was no correlation between the serum levels of VitB12, Hcy, and MMA and disease activity (p>0.05).

Conclusion

The results of this study suggest that there is no significant association between VitB12 deficiency and parenchymal NBS. Further studies are needed to investigate the underlying mechanisms of the variable effects of VitB12 deficiency on different clinical manifestations of BS.