Association of regular glucosamine use with incident dementia: evidence from a longitudinal cohort and Mendelian randomization study

Does Walking Have an Association with Osteoarthritis? A Two-Sample Mendelian Randomization Analysis

Objective

Osteoarthritis (OA) is one of the major disabling human diseases. The related studies indicate a potential correlation between walking and OA. However, there is still a lack of evidence in genetics to support the correlation between walking and OA. Therefore, this study aimed to explore the relationship between walking and OA at the genetic level.

Methods

The publicly available Genome Wide Association Study (GWAS) data were used, with inverse variance weighting (IVW, the random-effects model) as the main analysis method, whereas MR-Egger, Weighted median, Simple mode, and Weighted mode as the secondary analysis methods. In addition, Cochran's Q test, pleiotropy test, and MR-Egger intercept test were conducted to examine the heterogeneity and pleiotropy of the outcome.

Results

In the MR analysis, IVW results showed a negative correlation between types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and OA (KOA or HOA) (odds ratio (OR) = 0.3224, 95% confidence interval (CI): 0.1261 to 0.8243), and the difference was of statistical significance (P = 0.0181). Moreover, IVW results also revealed a negative correlation between types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and KOA (OR = 0.1396, 95% CI: 0.0484 to 0.4026), and the difference was statistically significant (P = 0.0003). However, IVW results did not demonstrate any statistical significance types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and HOA (OR = 1.2075, 95% CI: 0.1978 to 7.3727, P = 0.8381).

Conclusion

From genetic studies, types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) is negatively correlated with knee osteoarthritis (KOA), but there is no clear evidence supporting its correlation with hip osteoarthritis (HOA).

Structural Insights into the Catalytic Activity of Cyclobacterium marinum N-Acetylglucosamine Deacetylase

N-Acetylglucosamine deacetylase from Cyclobacterium marinum (CmCBDA) is a highly effective and selective biocatalyst for the production of d-glucosamine (GlcN) from N-acetylglucosamine (GlcNAc). However, the underlying catalytic mechanism remains elusive. Here, we show that CmCBDA is a metalloenzyme with a preference for Ni2+ over Mn2+. Crystal structures of CmCBDA in complex with Ni2+ and Mn2+ revealed slight remodeling of the CmCBDA active site by the metal ions. We also demonstrate that CmCBDA exists as a mixture of homodimers and monomers in solution, and dimerization is indispensable for catalytic activity. A mutagenesis analysis also indicated that the active site residues Asp22, His72, and His143 as well as the residues involved in dimerization, Pro52, Trp53, and Tyr55, are essential for catalytic activity. Furthermore, a mutation on the protein surface, Lys219Glu, resulted in a 2.3-fold improvement in the deacetylation activity toward GlcNAc. Mechanistic insights obtained here may facilitate the development of CmCBDA variants with higher activities.

Comprehensive Analysis of Metabolites in Postmortem Brains of Patients with Alzheimer's Disease

BACKGROUND

Disturbed metabolism has been proposed as being involved in the pathogenesis of Alzheimer's disease (AD), and more evidence from human AD brains is required.

OBJECTIVE

In this study, we attempted to identify or confirm modulations in the levels of metabolites associated with AD in postmortem AD brains.

METHODS

We performed metabolomics analyses using a gas chromatography mass spectrometry system in postmortem brains of patients with confirmed AD, patients with CERAD score B, and control subjects.

RESULTS

Impaired phosphorylation of glucose and elevation of several tricarboxylic acid (TCA) metabolites, except citrate, were observed and the degree of impaired phosphorylation and elevation in the levels of the TCA cycle metabolites were negatively and positively correlated, respectively, with the clinical phenotypes of AD. The levels of uronic acid pathway metabolites were modulated in AD and correlated positively with the amyloid-β content. The associations of nucleic acid synthesis and amino acid metabolites with AD depended on the kinds of metabolites; in particular, the contents of ribose 5-phosphate, serine and glycine were negatively correlated, while those of ureidosuccinic acid and indole-3-acetic acid were positively modulated in AD. Comprehensive statistical analyses suggested that alterations in the inositol pathway were most closely associated with AD.

CONCLUSIONS

The present study revealed many novel associations between metabolites and AD, suggesting that some of these might serve as novel potential therapeutic targets for AD.

Causal associations between common musculoskeletal disorders and dementia: a Mendelian randomization study

Introduction

Dementia and musculoskeletal disorders (MSDs) are major public health problems. We aimed to investigate the genetic causality of common MSDs and dementia.

Methods

Two-sample Mendelian randomization (MR) was used in this study. MR analysis based on gene-wide association study (GWAS) data on osteoarthritis (OA), dementia with Lewy bodies, and other MSDs and dementia types were obtained from the Genetics of Osteoarthritis consortium, IEU-open GWAS project, GWAS catalog, and FinnGen consortium. Rigorously selected single-nucleotide polymorphisms were regarded as instrumental variables for further MR analysis. Inverse-variance weighted, MR-Egger regression, weight median, simple mode, and weight mode methods were used to obtain the MR estimates. Cochran's Q test, MR-Egger and MR-Pleiotropy Residual Sum and Outlier analysis, and the leave-one-out test were applied for sensitivity testing.

Results

The inverse-variance weighted method showed that hip OA was genetically associated with a lower risk of dementia, unspecified dementia, dementia in Alzheimer's disease, and vascular dementia. Kneehip OA was inversely associated with unspecified dementia and vascular dementia. Rheumatoid arthritis, juvenile idiopathic arthritis and seronegative rheumatoid arthritis were inversely associated with frontotemporal dementia, and rheumatoid arthritis was inversely associated with unspecified dementia. Simultaneously, ankylosing spondylitis was an independent risk factor for dementia, dementia with Lewy bodies, and dementia in Alzheimer's disease. Sensitivity tests showed that heterogeneity and horizontal pleiotropy did not exist in these associations. The leave-one-out test showed that these associations were stable.

Conclusion

We found that some MSDs were associated with the risk of dementia and provide evidence for the early detection of dementia in patients with MSDs and for the impact of inflammation on the central nervous system.

A two-sample Mendelian randomization study of atherosclerosis and dementia

The causality between atherosclerosis and dementia remains unclear. This study aimed to explore the causal effect of atherosclerosis related indicators on dementia risk based on two-sample Mendelian randomization (MR) using summary statistics of genome-wide association studies (GWASs). The inverse variance weighted (IVW) method was performed as the main analysis, supplemented by different sensitivity analyses. Suggestive evidence indicated that peripheral arterial disease (PAD) (odds ratio (OR): 0.864, 95% confidence interval (CI): 0.797-0.937), coronary atherosclerosis (CoAS) (OR: 0.927, 95% CI: 0.860-0.998) and atherosclerosis, excluding cerebral, coronary, and PAD (ATHSCLE) (OR: 0.812, 95% CI: 0.725-0.909) were inversely associated with the risk of AD. The sensitivity analysis confirmed a suggestive reverse effect of ATHSCLE on the risk of frontotemporal dementia (FTD) (OR, 0.812, 95% CI, 0.725-0.909). Findings provide suggestive evidence that PAD, CoAS, and ATHSCLE might be associated with the risk of AD or FTD, which requires further exploration in larger samples.

Habitual glucosamine use, APOE genotypes, and risk of incident cause-specific dementia in the older population

BACKGROUND

The relationship of glucosamine use with incident dementia in the older population remains uncertain. We aimed to evaluate the longitudinal association between habitual glucosamine supplement and the risk of cause-specific dementia and examine the possible effect modifiers on this association.

METHODS

The study included 214,945 participants over the age of 60 who had available information on glucosamine use and did not have dementia at baseline in the UK Biobank. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. The primary outcome was incident vascular dementia, incident Alzheimer's disease, and incident frontotemporal dementia, respectively.

RESULTS

Over a median follow-up duration of 12 years, 1039, 1774, and 122 participants developed vascular dementia, Alzheimer's disease, and frontotemporal dementia, respectively. Overall, habitual glucosamine use was significantly associated with a lower risk of incident vascular dementia (adjusted HR, 0.82; 95%CI, 0.70-0.96), but not significantly associated with incident Alzheimer's disease (adjusted HR, 1.02; 95%CI, 0.92-1.14) and incident frontotemporal dementia (adjusted HR, 0.95; 95%CI, 0.63-1.43). Moreover, the inverse association between habitual glucosamine use and incident vascular dementia was more pronounced in participants with concomitant supplement of calcium (P-interaction = 0.011), and those without concomitant supplement of zinc (P-interaction = 0.018). However, APOE ε4 dosage and baseline cognitive function did not significantly modify the relationships of glucosamine use with incident vascular dementia or Alzheimer's disease (All P-interactions > 0.05).

CONCLUSIONS

Regardless of APOE genotypes and baseline cognitive function, habitual glucosamine use was significantly inversely associated with incident vascular dementia in the older population.

Causal Effect of Chondroitin, Glucosamine, Vitamin, and Mineral Intake on Kidney Function: A Mendelian Randomization Study

The causal effects of chondroitin, glucosamine, and vitamin/mineral supplement intake on kidney function remain unknown, despite being commonly used. We conducted a two-sample summary-level Mendelian randomization (MR) analysis to test for causal associations between regular dietary supplement intake and kidney function. Genetic instruments for chondroitin, glucosamine, and vitamin/mineral supplement intake were obtained from a genome-wide association study of European ancestry. Summary statistics for the log-transformed estimated glomerular filtration rate (log-eGFR) were provided by the CKDGen consortium. The multiplicative random-effects inverse-variance weighted method showed that genetically predicted chondroitin and glucosamine intake was causally associated with a lower eGFR (chondroitin, eGFR change beta = -0.113%, standard error (SE) = 0.03%, p-value = 2 × 10-4; glucosamine, eGFR change beta = -0.240%, SE = 0.035%, p-value = 6 × 10-12). However, a genetically predicted vitamin/mineral supplement intake was associated with a higher eGFR (eGFR change beta = 1.426%, SE = 0.136%, p-value = 1 × 10-25). Validation analyses and pleiotropy-robust MR results for chondroitin and vitamin/mineral supplement intake supported the main results. Our MR study suggests a potential causal effect of chondroitin and glucosamine intake on kidney function. Therefore, clinicians should carefully monitor their long-term effects.