Economic Impact of Hyperhomocysteinemia in Switzerland

Novel Therapy of Hyperhomocysteinemia in Mild Cognitive Impairment, Alzheimer's Disease, and Other Dementing Disorders

OBJECTIVES

Studies have produced conflicting results assessing hyperhomocysteinemia (HYH) treatment with B vitamins in patients with normal cognition, Alzheimer's disease and related disorders (ADRD). This study examined the effect of HYH management with L-methylfolate (LMF), methylcobalamin (MeCbl; B12), and N-acetyl-cysteine (CFLN: Cerefolin®/Cerefolin-NAC®) on cognitive decline.

DESIGN

Prospective, case-control study of subjects followed longitudinally.

SETTING

Outpatient clinic for cognitive disorders.

PARTICIPANTS

116 ADRD patients (34 with HYH, 82 with No-HYH) met inclusion and exclusion criteria to participate. No study participant took B vitamins.

INTERVENTION

HYH patients received CFLN, and No-HYH patients did not.

MEASUREMENTS

Cognitive outcome measures included MCI Screen (memory), CERAD Drawings (constructional praxis), Ishihara Number Naming (object recognition), Trails A and B (executive function), and F-A-S test (verbal fluency). Dependent or predictor measures included demographics, functional severity, CFLN and no CFLN treatment duration, ADRD diagnosis, memantine and cholinesterase inhibitor treatment. Linear mixed effects models with covariate adjustment were used to evaluate rate of change on cognitive outcomes.

RESULTS

The duration of CFLN treatment, compared to an equivalent duration without CFLN treatment, significantly slowed decline in learning and memory, constructional praxis, and visual-spatial executive function (Trails B). CFLN treatment slowed cognitive decline significantly more for patients with milder baseline severity. CFLN treatment effect increased as baseline functional severity decreased. The analytical model showed that treatment duration must exceed some minimum period of at least one year to slow the rate of cognitive decline.

CONCLUSION

After covariate adjustment, HYH+CFLN significantly slowed cognitive decline compared to No-HYH+No-CFLN. Longer CFLN treatment duration, milder baseline severity, and magnitude of homocysteine reduction from baseline were all significant predictors. There are a number of factors that could account for disagreement with other clinical trials of B vitamin treatment of HYH. Moreover, CFLN is chemically distinct from commonly used B vitamins as both LMF and MeCbl are the fully reduced and bioactive functional forms; CLFN also contains the glutathione precursor, N-acetyl-cysteine. The findings of other B vitamin trials of HYH can, therefore, only partly account for treatment effects of CFLN. These findings warrant further evaluation with a randomized, placebo-controlled trial.

Correlation of methylenetetrahydrofolate reductase polymorphisms with homocysteine metabolism in healthy Lebanese adults

Hyperhomocysteinemia is associated with several vascular and teratogenic conditions. Determinants of total homocysteine concentrations include genetic and nutritional factors. This study assesses the relation between homocysteine concentrations and MTHFR gene polymorphisms at two common alleles (C677T (rs1801133) and A1298C (rs1801131)) as well as other predictors of homocysteine (folate, vitamin B(12), body mass index (BMI), age, and gender) in a group of healthy Lebanese: 109 males and 124 females aged 17-55years. We used serum for the determination of homocysteine, folate and vitamin B(12) levels and blood drawn in EDTA tubes for molecular analysis of MTHFR polymorphisms. Hyperhomocysteinemia was present in 59/233 (25.3%) of the subjects, with male/female ratio of 1.95. Multivariable regression analysis showed that homocysteine levels were negatively related to folate and vitamin B(12) and positively related to male gender and C677T homozygosity; but not A1298C polymorphism, BMI or age. The prevalence of wild, heterozygous, and homozygous C677T genotypes was 45.0%, 43.3% and 11.6%, respectively; with a carrier frequency of 54.9% and allelic frequency of 33.3%. The A1298C genotypic prevalence was 39.5%, 30.9%, and 29.6% respectively; with a carrier frequency of 60.5% and allelic frequency of 45.1%. C677T/A1289C compound heterozygosity was present in 47/233 (20.2%) of volunteers. In this first pilot study, gender, folate, vitamin B(12) and C677T mutational status could explain around 32% of homocysteine variations. Future larger studies are recommended to investigate other predictors of homocysteine variation and combine them with markers explored in this and other studies, in order to evaluate their impact on vascular and/or congenital diseases.