Prevalence of hyperhomocysteinemia in an elderly population

A micronutrient supplement modulates homocysteine levels regardless of vitamin B biostatus in elderly subjects

Elevated homocysteine (Hcy) levels (≥15 μmol/L) in the elderly are frequently associated with a higher risk of cardiovascular disease and cognitive decline. Several studies have already shown an Hcy-lowering effect of B vitamin supplementation in cohorts deficient in these nutrients. The aim of this randomized, double-blinded 12-week intervention study was to investigate whether Hcy levels in healthy elderly subjects (75.4±4.5 years, n=133) could be lowered with a micronutrient supplement (i.e., 400 μg folic acid, 100 μg cobalamin). Difference in mean initial Hcy levels between intervention (17.6±7.1 μmol/L, n=65) and placebo group (18.9±6.1 μmol/L, n=68) was not significant. The prevalence of cobalamin and folate deficiency in the total study population was low: 27% had serum-cobalamin levels ≤150 pmol/L, 12% holo-transcobalamin (Holo-TC) levels ≤50 pmol/L, 13% low cobalamin status using the aggregated cobalamin marker 4cB12 and 10% red blood cell (RBC) folate ≤570 nmol/L. Nevertheless, the treated subjects still showed improved cobalamin and folate biostatus (serum cobalamin Δt12-t0: 63±48 pmol/L; Holo-TC Δt12-t0: 17±19 pmol/L; RBC folate Δt12-t0: 326±253 nmol/L) and Hcy levels (Δt12-t0: -3.6±5.7 μmol/L). The effects were statistically significant compared to the placebo group with p=0.005 (serum cobalamin), p=0.021 (Holo-TC), p=0.014 (RBC-folate) and p<0.001 (Hcy). The Hcy-lowering effect was dependent on the initial Hcy levels (p<0.001). Our findings suggest that elevated Hcy levels in elderly subjects can be lowered regardless of the initial cobalamin and folate biostatus.

Effects of Supplementation with Folic Acid and Its Combinations with Other Nutrients on Cognitive Impairment and Alzheimer's Disease: A Narrative Review

Cognitive impairment and Alzheimer's Disease, among other cognitive dysfunctions, has been recognized as a major public health problem. Folic acid is a well-known essential nutrient whose deficiency has been linked to neurocognitive dysfunctions, owing to hyperhomocysteinemia, an independent risk factor for cardio- and cerebrovascular diseases, including cognitive impairment, Alzheimer's Disease, and vascular dementia. However, to date, there is certain controversy about the efficacy of vitamin supplementation in patients with these pathologies. Therefore, we have reviewed the available dietary intervention studies based on folic acid, either alone or in combination with different vitamins or nutrients into the progression of Alzheimer's Disease and Cognitive impairment, highlighting the cognition and biochemical markers employed for the evaluation of the disease progression. Undeniably, the compiled information supports the potential benefits of vitamin supplementation in these pathologies, especially relevant to the aging process and quality of life, although more research is urgently needed to confirm these positive findings.

Impact of supplementation with vitamins B6 , B12 , and/or folic acid on the reduction of homocysteine levels in patients with mild cognitive impairment: A systematic review

Hyperhomocysteinemia is an independent predictor of the risk for cognitive decline and may be a result of low levels of vitamins B₁₂ , B₆ , and folate. Previous findings suggest that adequate intake of these vitamins may reduce homocysteine levels. This review aimed to assess the effects of treatment with vitamins B_6, B₁₂ , and/or folic acid in the homocysteine levels in patients with mild cognitive impairment (MCI). A systematic literature review was conducted in EMBASE, MEDLINE®, PsycINFO, and Cochrane Central Register of Controlled Trials. The research question was formulated using the Population, Intervention, Comparison, and Outcome (PICO) framework: in patients with MCI (P); what is the efficacy of vitamins B₆ , B₁₂ , and/or folic acid intake (I); compared with baseline values, and/or compared with controls (C); in reducing homocysteine levels from baseline (O). A total of eight primary studies with a total of 1,140 participants were included in the review. Four were randomized controlled trials, one was a quasi-controlled trial, and three were observational studies. All studies included folic acid in their intervention, seven vitamin B₁₂ , and four vitamin B₆ . Mean (SD) length of the intervention period was 18.8 (19.3) months, ranging from 1 to 60 months. All studies showed a statistically significant decrease in homocysteine levels in groups treated with vitamins B_6, B₁₂ , and/or folic acid compared to controls, with a mean decline of homocysteine concentration of 31.9% in the intervention arms whereas it increased by 0.7% in the control arm. This review identified evidence of a reduction of plasma homocysteine levels in MCI patients taking vitamins B_6, B₁₂ , and/or folic acid supplements, with statistically significant declines being observed after 1 month of supplementation. Findings support that supplementation with these vitamins might be an option to reduce homocysteine levels in people with MCI and elevated plasma homocysteine.

Hyperhomocysteinemia and its relations to conventional risk factors for cardiovascular diseases in adult Nigerians: the REMAH study

BACKGROUND

Evidence linking homocysteine (Hcy) with cardiovascular diseases (CVD) or its risk factors are limited in a sub-Saharan black population.

OBJECTIVE

We set out to evaluate the association between Hcy and hypertension and other CVD risk factors in a population of adult Nigerians.

METHODS

Data of 156 adults aged 18-70 years was accessed from the North Central study site of the REmoving the MAsk on Hypertension (REMAH) study. Homocysteine, blood glucose and lipid profile in whole blood/serum were measured using standard laboratory methods. Hypertension was diagnosed if average of 5 consecutive blood pressure (BP) measurements obtained using a mercury sphygmomanometer was equal to or higher than 140 systolic and/or 90 mmHg diastolic or the individual is on antihypertensive medication. Hyperhomocysteinemia (HHcy) was defined as Hcy > 10 µmol/L.

RESULTS

Of the 156 participants, 72 (43.5%) were hypertensive, of whom 18 had HHcy. Subjects with HHcy were significantly (p < 0.05) older (41.5 vs. 40.6yrs), had lower HDL-cholesterol (0.6 vs. 0.8 mmol/L) and higher systolic (145.5 vs. 126.0 mmHg) and diastolic BP (92.9 vs. 79.6 mmHg), compared to those without HHcy. Intake of alcohol and a 1 yr increase in age were respectively and significantly (p < 0.05) associated with a 1.54 and 0.10 µmol/L increase in Hcy. In a multivariable model adjusted for age, sex and body mass index, a 1 µmol/L increase in Hcy, was associated with a 1.69 mmHg and 1.34 mmHg increase in systolic and diastolic pressure (p < 0.0001) respectively; and a 0.01 mmol/L decrease in HDL-cholesterol (p < 0.05).

CONCLUSION

HHcy occurs among hypertensive Nigerians and it is independently associated with age, HDL-cholesterol, systolic and diastolic BP.

Hyperhomocysteinemia is an emerging comorbidity in ischemic stroke

Hyperhomocysteinemia or systemic elevation of the amino acid homocysteine is a common metabolic disorder that is considered to be a risk factor for ischemic stroke. However, it is still unclear whether predisposition to hyperhomocysteinemia could contribute to the severity of stroke outcome. This review highlights the advantages and limitations of the current rodent models of hyperhomocysteinemia, describes the consequence of mild hyperhomocysteinemia on the severity of ischemic brain damage in preclinical studies and summarizes the mechanisms involved in homocysteine induced neurotoxicity. The findings provide the premise for establishing hyperhomocysteinemia as a comorbidity for ischemic stroke and should be taken into consideration while developing potential therapeutic agents for stroke treatment.

Microglial-associated responses to comorbid amyloid pathology and hyperhomocysteinemia in an aged knock-in mouse model of Alzheimer's disease

BACKGROUND

Elevated blood homocysteine levels, termed hyperhomocysteinemia (HHcy), is a prevalent risk factor for Alzheimer's disease (AD) in elderly populations. While dietary supplementation of B-vitamins is a generally effective method to lower homocysteine levels, there is little if any benefit to cognition. In the context of amyloid pathology, dietary-induced HHcy is known to enhance amyloid deposition and certain inflammatory responses. Little is known, however, about whether there is a more specific effect on microglia resulting from combined amyloid and HHcy pathologies.

METHODS

The present study used a knock-in mouse model of amyloidosis, aged to 12 months, given 8 weeks of B-vitamin deficiency-induced HHcy to better understand how microglia are affected in this comorbidity context.

RESULTS

We found that HHcy-inducing diet increased amyloid plaque burden, altered the neuroinflammatory milieu, and upregulated the expression of multiple damage-associated and "homeostatic" microglial genes.

CONCLUSIONS

Taken together, these data indicate complex effects of comorbid pathologies on microglial function that are not driven solely by increased amyloid burden. Given the highly dynamic nature of microglia, their central role in AD pathology, and the frequent occurrence of various comorbidities in AD patients, it is increasingly important to understand how microglia respond to mixed pathological processes.

Hyperhomocysteinemia leads to exacerbation of ischemic brain damage: Role of GluN2A NMDA receptors

Hyperhomocysteinemia has been implicated in several neurodegenerative disorders including ischemic stroke. However, the pathological consequences of ischemic insult in individuals predisposed to hyperhomocysteinemia and the associated etiology are unknown. In this study, we evaluated the outcome of transient ischemic stroke in a rodent model of hyperhomocysteinemia, developed by subcutaneous implantation of osmotic pumps containing L-homocysteine into male Wistar rats. Our findings show a 42.3% mortality rate in hyperhomocysteinemic rats as compared to 7.7% in control rats. Magnetic resonance imaging of the brain in the surviving rats shows that mild hyperhomocysteinemia leads to exacerbation of ischemic injury within 24 h, which remains elevated over time. Behavioral studies further demonstrate significant deficit in sensorimotor functions in hyperhomocysteinemic rats compared to control rats. Using pharmacological inhibitors targeting the NMDAR subtypes, the study further demonstrates that inhibition of GluN2A-containing NMDARs significantly reduces ischemic brain damage in hyperhomocysteinemic rats but not in control rats, indicating that hyperhomocysteinemia-mediated exacerbation of ischemic brain injury involves GluN2A-NMDAR signaling. Complementary studies in GluN2A-knockout mice show that in the absence of GluN2A-NMDARs, hyperhomocysteinemia-associated exacerbation of ischemic brain injury is blocked, confirming that GluN2A-NMDAR activation is a critical determinant of the severity of ischemic damage under hyperhomocysteinemic conditions. Furthermore, at the molecular level we observe GluN2A-NMDAR dependent sustained increase in ERK MAPK phosphorylation under hyperhomocysteinemic condition that has been shown to be involved in homocysteine-induced neurotoxicity. Taken together, the findings show that hyperhomocysteinemia triggers a unique signaling pathway that in conjunction with ischemia-induced pathways enhance the pathology of stroke under hyperhomocysteinemic conditions.

Blood Flow Deficits and Cerebrovascular Changes in a Dietary Model of Hyperhomocysteinemia

Elevated homocysteine in the blood, or hyperhomocysteinemia, is a recognized risk factor for multiple causes of dementia including Alzheimer’s disease. While reduction of homocysteine levels can generally be accomplished in a straightforward manner, the evidence regarding the cognitive benefits of this approach is less clear. To identify adjunct therapeutic targets that might more effectively restore cognition, the present series of experiments characterizes early and later cerebrovascular changes in a model of hyperhomocysteinemia. Sex-balanced groups of adult C57BL/6J mice were administered a diet deficient in vitamins B6, B12, and B9 (folate) and supplemented with excess methionine. They were subsequently assessed for changes in cerebral blood flow, memory, blood–brain barrier permeability, and selected vascular-associated genes. Blood flow deficits and barrier permeability changes occurred alongside changes in memory and in genes associated with metabolism, endothelial nitric oxide signaling, barrier integrity, and extracellular matrix remodeling. Significant sexually dimorphic responses to the diet were also detected. Taken together, these data deepen our understanding of a major contributor to dementia burden.

Vitamin Status and the Development of Postoperative Cognitive Decline in Elderly Surgical Oncologic Patients

Background

This study aimed to evaluate the influence that serum levels of vitamin B12, folate, and homocysteine have on the development of short-term postoperative cognitive decline in the elderly surgical oncology patient.

Methods

This study was part of a prospective cohort study focused on postoperative cognitive outcomes for patients 65 years of age or older undergoing surgery for a solid malignancy. Postoperative cognitive decline was defined as the change in the combined results of the Ruff Figural Fluency Test and the Trail-Making Test Parts A and B. Patients with the highest change in scores 2 weeks postoperatively compared with baseline were considered to be patients with cognitive decline. Patients with the lowest change were considered to be patients without cognitive decline. To analyze the effect of vitamin levels on the changes in postoperative cognitive scores, uni- and multivariate logistic regression analysis were performed.

Results

The study enrolled 61 patients with and 59 patients without postoperative cognitive decline. Hyperhomocysteinemia was present in 14.2% of the patients. Patients with postoperative cognitive decline more often had hyperhomocysteinemia (27.9 vs 10.2%). Hyperhomocysteinemia was associated with a higher chance for the development of postoperative cognitive decline (odds ratio_adjusted, 11.9; 95% confidence interval, 2.4–59.4). Preoperative vitamin B12 or folate deficiency were not associated with the development of postoperative cognitive decline.

Conclusion

Preoperative hyperhomocysteinemia is associated with the development of postoperative cognitive decline. The presence of preoperative hyperhomocysteinemia could be an indicator for an increased risk of postoperative cognitive decline developing in the elderly.

Incorporation of a high level of vitamin B12 into a vegetable, kaiware daikon (Japanese radish sprout), by the absorption from its seeds

High level of vitamin B(12) was incorporated into kaiware daikon (Japanese radish sprout) by soaking its seeds in B(12) solutions. Vitamin B(12) amount incorporated into kaiware daikon increased up to 1.5 microg/g wet sprout with the soaking time of seeds in 0-200 microg/ml B(12) solution. Vitamin B(12) could be extracted more from the sample heated for a short time than from that of control without heat treatment.