B-Vitamin Therapy for Kidney Transplant Recipients Lowers Homocysteine and Improves Selective Cognitive Outcomes in the Randomized FAVORIT Ancillary Cognitive Trial

Vitamin B6 and vitamin D deficiency co-occurrence in geriatric memory patients

INTRODUCTION

Vitamin B6 and D levels are not assessed routinely in geriatric memory patients. This study examined vitamin levels to determine the potential effects on cognition.

METHODS

A chart review was conducted of 203 consecutive patients over a 12-month period. Levels of vitamins B1, B6, B12, and D were obtained on the day of clinic to identify deficiencies. A mental status exam (Mini Mental State Examination [MMSE]) was also performed.

RESULTS

One hundred sixty-seven patients had one or more vitamin levels obtained on the day of clinical evaluation. Vitamin B6 deficiency was the most common (37.5%), followed by vitamin D deficiency (36.8%). A chi-square test revealed significant co-occurrence of deficiency of vitamins B6 and D (p < 0.001). Vitamin B6 and D deficiencies were associated with lower MMSE scores (p < 0.05).

DISCUSSION

Vitamin B6 and D deficiencies are common in geriatric patients. The coexistence of these vitamin deficiencies has a significant association with cognitive performance, indicating the clinical importance of monitoring and supplementation.

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.

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.

Minor allele of rs55763075 located in MTHFR is associated with the risk of cognitive impairment after anesthesia via modulating miR-34b

This study aimed to investigate the association between cognitive impairment after general anesthesia and rs55763075 polymorphisms. We enrolled and grouped patients undergoing general anesthesia according to their genotypes of rs55763075 polymorphism. Mini–Mental State Examination (MMSE) scoring was performed to evaluate the cognitive status of patients. Quantitative real-time PCR was carried out to analyze the expression of methylenetetrahydrofolate reductase (MTHFR) mRNA and miR-34b while Western blot was performed to evaluate the expression of MTHFR protein. Furthermore, we studied the effect of rs55763075 polymorphism on the expression of MEHFR via luciferase assay. Accordingly, we found that the MMSE score in GG/GA groups was significantly higher than that in AA group. And a significant reduction of MTHFR mRNA expression was observed in the serum and peripheral blood mononuclear cells (PBMCs) of patients carrying AA genotype compared with the patients carrying GG/GA genotypes. Moreover, the MTHFR expression was much lower in the cultured AA-genotyped cells transfected with miR-34b. Luciferase assay results also showed that miR-34b transfection reduced luciferase activity in the cells carrying A allele but not in cells carrying G allele. In summary, the data of this study showed that minor allele (A) of rs55763075 polymorphisms in the 3'-untranslated region of MTHFR mRNA generated a potential binding site for miR-34b, which led to reduced level of folic acid in the patients carrying the AA genotype. Furthermore, we found that the MMSE score of AA-genotyped patients was lower than that of patients carrying GG/GA genotypes.

Interventions to Preserve Cognitive Functioning Among Older Kidney Transplant Recipients

PURPOSE OF REVIEW

To summarize the research on effective interventions for preserving cognitive function and prevent cognitive decline in patients with end-stage kidney disease (ESKD) who are undergoing dialysis and/or kidney transplantation (KT).

RECENT FINDINGS

Among ESKD patients undergoing hemodialysis, exercise training has been administered through home-based and intradialytic interventions. Additionally, one pilot study identified intradialytic cognitive training, electronic brain games, as an intervention to preserve cognitive function among patients undergoing hemodialysis. Fewer studies have investigated interventions to preserver cognitive function among KT recipients. To date, the only randomized controlled trial in this population identified B-vitamin supplements as an intervention to preserve cognitive function. The evidence from these trials support a short-term benefit of cognitive and exercise training as well as B-vitamin supplementation among patients with ESKD. Future studies should: 1) replicate these findings, 2) identify interventions specific to KT candidates, and 3) investigate the synergistic impact of both cognitive and exercise training.

SUMMARY

Cognitive prehabilitation, with cognitive and/or exercise training, may be novel interventions for KT candidates that not only reduces delirium risk and long-term post-KT cognitive decline but also prevents dementia.

Efficacy of Vitamins on Cognitive Function of Non-Demented People: A Systematic Review and Meta-Analysis

Previous evidence has suggested that vitamins might be beneficial for cognition. This systematic review aimed to investigate the efficacy of B vitamins, antioxidant vitamins, and vitamin D on the cognitive function of non-demented middle-aged or older people. Randomized or quasi-randomized controlled trials of individuals aged 40 years or older were included. PubMed/MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Library databases, and other grey literature sources were searched up to November 2019. Their methodological quality was evaluated using the Cochrane Risk of Bias tool. Twenty-three studies on B vitamins (n = 22-1053; comprising folate, B6, and B12), nine on antioxidant vitamins (n = 185-20,469), and six on vitamin D (n = 55-4122) were included. Taking B vitamins for over 3 months was beneficial for global cognition (standardized mean difference (SMD) -0.18, 95% CI -0.30 to -0.06) and episodic memory (SMD -0.09, 95% CI -0.15 to -0.04). However, antioxidant vitamins (SMD -0.02, 95% CI -0.08 to 0.03) and vitamin D (SMD -0.06, 95% CI -0.36 to 0.23) were not. Antioxidant vitamins were beneficial for global cognition in sensitivity analyses using final measurement data as mean difference estimates (SMD, -0.04, 95% CI -0.08 to -0.01). Taking B vitamins and possibly antioxidant vitamins may be beneficial for the cognitive function of non-demented people.

Folic Acid and Vitamin B12 Administration in CKD, Why Not?

Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Since traditional risk factors cannot fully explain such increased cardiovascular risk, interest in non-traditional risk factors, such as hyperhomocysteinemia and folic acid and vitamin B12 metabolism impairment, is growing. Although elevated homocysteine blood levels are often seen in patients with CKD and ESRD, whether hyperhomocysteinemia represents a reliable cardiovascular and mortality risk marker or a therapeutic target in this population is still unclear. In addition, folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. The purpose of this review was to highlight homocysteine, folic acid and vitamin B12 metabolism impairment in CKD and ESRD and to summarize available evidences on hyperhomocysteinemia, folic acid and vitamin B12 as cardiovascular risk markers, therapeutic target and risk factors for CKD progression.