J Clin Med

Frailty and sarcopenia are characterized by a loss of muscle mass and functionality and are diagnosed mainly by functional tests and imaging parameters. However, more muscle specific biomarkers are needed to improve frailty diagnosis. Plasma 3-methylhistidine (3-MH), as well as the 3-MH-to-creatinine (3-MH/Crea) and 3-MH-to-estimated glomerular filtration rate (3-MH/eGFR) ratios might support the diagnosis of frailty. Therefore, we investigated the cross-sectional associations between plasma 3-MH, 3-MH/Crea and 3-MH/eGFR with the frailty status of community-dwelling individuals (>65 years). 360 participants from two French cohorts of the FRAILOMIC initiative were classified into robust, pre-frail and frail according to Fried's frailty criteria. General linear models as well as bivariate and multiple linear and logistic regression models, which were adjusted for several confounders, were applied to determine associations between biomarkers and frailty status. The present study consisted of 37.8% robust, 43.1% pre-frail and 19.2% frail participants. Frail participants had significantly higher plasma 3-MH, 3-MH/Crea and 3-MH/eGFR ratios than robust individuals, and these biomarkers were positively associated with frailty status. Additionally, the likelihood to be frail was significantly higher for every increase in 3-MH (1.31-fold) and 3-MH/GFR (1.35-fold) quintile after adjusting for confounders. We conclude that 3-MH, 3-MH/Crea and 3-MH/eGFR in plasma might be potential biomarkers to identify frail individuals or those at higher risk to be frail, and we assume that there might be biomarker thresholds to identify these individuals. However, further, especially longitudinal studies are needed

Plasma carotenoids, tocopherols and retinol: Association with age in the Berlin Aging Study II

Regular consumption of fruits and vegetables, which is related to high plasma levels of lipid-soluble micronutrients such as carotenoids and tocopherols, is linked to lower incidences of various age-related diseases. Differences in lipid-soluble micronutrient blood concentrations seem to be associated with age. Our retrospective analysis included men and women aged 22–37 and 60–85 years from the Berlin Aging Study II. Participants with simultaneously available plasma samples and dietary data were included (n = 1973). Differences between young and old groups were found for plasma lycopene, α-carotene, α-tocopherol, β-cryptoxanthin (only in women), and γ-tocopherol (only in men). β-Carotene, retinol and lutein/zeaxanthin did not differ between young and old participants regardless of the sex. We found significant associations for lycopene, α-carotene (both inverse), α-tocopherol, γ-tocopherol, and β-carotene (all positive) with age. Adjusting for BMI, smoking status, season, cholesterol and dietary intake confirmed these associations, except for β-carotene. These micronutrients are important antioxidants and associated with lower incidence of age-related diseases, therefore it is important to understand the underlying mechanisms in order to implement dietary strategies for the prevention of age-related diseases. To explain the lower lycopene and α-carotene concentration in older subjects, bioavailability studies in older participants are necessary

Dietary Inflammatory Index and Cross-Sectional Associations with Inflammation, Muscle Mass and Function in Healthy Old Adults

IMORTANCE: Inflammaging is considered a driver of age-related loss of muscle mass and function (sarcopenia). As nutrition might play a role in this process, the Dietary Inflammatory Index® (DII) has been developed to quantify the inflammatory potential of an individual diet. OBJECTIVES: We aimed to examine associations between the DII, inflammation, oxidative stress and sarcopenia-related parameters in healthy old compared to young adults. Design, Setting, and Participants This cross-sectional study included data of 79 community-dwelling, healthy old adults (65–85 years) and 59 young adults (18–35 years) who participated in a randomized controlled trial from April to December 2019. MEASUREMENTS: The DII was computed with dietary data collected from 24-h recall interviews. Associations between the DII, inflammatory and oxidative stress markers as well as bioimpedance-derived body composition, handgrip strength and gait speed were determined with multiple linear regression analyses adjusted for age, sex, physical activity and insulin resistance. RESULTS: Regression analyses revealed significant relationships between a higher interleukin (IL) 6 and IL-6:IL-10-ratio and higher percentage fat mass (%FM), waist-to-height-ratio (WHtR) as well as lower percentage skeletal muscle mass (%SMM) and gait speed exclusively in old adults. Subsequent analyses showed that IL-6 was associated with a pro-inflammatory diet as indicated by a higher DII, again exclusively in old adults (beta coefficient (β)= 0.027, standard error (SE) 0.013, p=0.037). While the DII was not related with handgrip strength or oxidative stress in neither old nor young adults, linear models confirmed that a higher DII was inversely associated with gait speed in old participants (β= −0.022, SE 0.006, p<0.001). Finally, a pro-inflammatory diet was significantly associated with higher %FM, WHtR and lower %SMM in both age groups. CONCLUSION AND RELEVANCE: A pro-inflammatory diet reflected by the DII is associated with higher systemic inflammation, slower gait speed as well as lower muscle mass in old adults. Intervention studies are needed to examine whether anti-inflammatory dietary approaches can help to improve muscle mass and function and thus minimize the risk for sarcopenia in the long-term

J Cachexia Sarcopenia Muscle

BACKGROUND: A poor fat-soluble micronutrient (FMN) and a high oxidative stress status are associated with frailty. Our aim was to determine the cross-sectional association of FMNs and oxidative stress biomarkers [protein carbonyls (PrCarb) and 3-nitrotyrosine] with the frailty status in participants older than 65 years. METHODS: Plasma levels of vitamins A (retinol), D3 , E (alpha-tocopherol and gamma-tocopherol) and carotenoids (alpha-carotene and beta-carotene, lycopene, lutein/zeaxanthin, and beta-cryptoxanthin), PrCarb, and 3-nitrotyrosine were measured in 1450 individuals of the FRAILOMIC initiative. Participants were classified into robust, pre-frail, and frail using Fried's frailty criteria. Associations between biomarkers and frailty status were assessed by general linear and logistic regression models, both adjusted for cohort, season of blood sampling, gender, age, height, weight, and smoking. RESULTS: Robust participants had significantly higher vitamin D3 and lutein/zeaxanthin concentrations than pre-frail and frail subjects; had significantly higher gamma-tocopherol, alpha-carotene, beta-carotene, lycopene, and beta-cryptoxanthin concentrations than frail subjects, and had significantly lower PrCarb concentrations than frail participants in multivariate linear models. Frail subjects were more likely to be in the lowest than in the highest tertile for vitamin D3 (adjusted odds ratio: 2.15; 95% confidence interval: 1.42-3.26), alpha-tocopherol (2.12; 1.39-3.24), alpha-carotene (1.69; 1.00-2.88), beta-carotene (1.84; 1.13-2.99), lycopene (1.94; 1.24-3.05), lutein/zeaxanthin (3.60; 2.34-5.53), and beta-cryptoxanthin (3.02; 1.95-4.69) and were more likely to be in the highest than in the lowest tertile for PrCarb (2.86; 1.82-4.49) than robust subjects in multivariate regression models. CONCLUSIONS: Our study indicates that both low FMN and high PrCarb concentrations are associated with pre-frailty and frailty

Frailty is characterized by biomarker patterns reflecting inflammation or muscle catabolism in multi-morbid patients

BACKGROUND: Frailty development is partly dependent on multiple factors like low levels of nutrients and high levels of oxidative stress (OS) and inflammation potentially leading to a muscle-catabolic state. Measures of specific biomarker patterns including nutrients, OS and inflammatory biomarkers as well as muscle related biomarkers like 3-methylhistidine (3MH) may improve evaluation of mechanisms and the complex networks leading to frailty. METHODS: In 220 multi-morbid patients (≥ 60 years), classified as non-frail (n = 104) and frail (n = 116) according to Fried's frailty criteria, we measured serum concentrations of fat-soluble micronutrients, amino acids (AA), OS, interleukins (IL) 6 and 10, 3MH (biomarker for muscle protein turnover) and serum spectra of fatty acids (FA). We evaluated biomarker patterns by principal component analysis (PCA) and their cross-sectional associations with frailty by multivariate logistic regression analysis. RESULTS: Two biomarker patterns [principal components (PC)] were identified by PCA. PC1 was characterized by high positive factor loadings (FL) of carotenoids, anti-inflammatory FA and vitamin D3 together with high negative FL of pro-inflammatory FA, IL6 and IL6/IL10, reflecting an inflammation-related pattern. PC2 was characterized by high positive FL of AA together with high negative FL of 3MH-based biomarkers, reflecting a muscle-related pattern. Frail patients had significantly lower factor scores than non-frail patients for both PC1 [median: −0.27 (interquartile range: 1.15) vs. 0.27 (1.23); P = 0.001] and PC2 [median: −0.15 (interquartile range: 1.13) vs. 0.21 (1.38); P = 0.002]. Patients with higher PC1 or PC2 factor scores were less likely to be frail [odds ratio (OR): 0.62, 95% CI: 0.46–0.83, P = 0.001 for PC1; OR: 0.64, 95% CI: 0.48–0.86, P = 0.003 for PC2] compared with patients with lower PC1 or PC2 factor scores. This indicates that increasing levels of anti-inflammatory biomarkers and increasing levels of muscle-anabolic biomarkers are associated with a reduced likelihood (38% and 36%, respectively) for frailty. Significant associations remained after adjusting the regression models for potential confounders. CONCLUSIONS: We conclude that two specific patterns reflecting either inflammation-related or muscle-related biomarkers are both significantly associated with frailty among multi-morbid patients and that these specific biomarker patterns are more informative than single biomarker analyses considering frailty identification

Quantifying technical confounders in microbiome studies

AIMS: Recent technical developments have allowed the study of the human microbiome to accelerate at an unprecedented pace. Methodological differences may have considerable impact on the results obtained. Thus, we investigated how different storage, isolation and DNA extraction methods can influence the characterization of the intestinal microbiome, compared to the impact of true biological signals such as intraindividual variability, nutrition, health and demographics. METHODS AND RESULTS: An observative cohort study in 27 healthy subjects was performed. Participants were instructed to collect stool samples twice spaced by a week, using six different methods (naive and Zymo DNA/RNA Shield on dry ice, OMNIgene GUT, RNALater, 95% ethanol, Zymo DNA/RNA Shield at room temperature). DNA extraction from all samples was performed comparatively using QIAamp Power Fecal and ZymoBIOMICS DNA kits. 16S rRNA sequencing of the gut microbiota as well as qPCRs were performed on the isolated DNA. Metrics included alpha diversity as well as multivariate and univariate comparisons of samples, controlling for covariate patterns computationally. Interindividual differences explained 7.4% of overall microbiome variability, whereas the choice of DNA extraction method explained a further 5.7%. At phylum level, the tested kits differed in their recovery of gram-positive bacteria, which is reflected in a significantly skewed enterotype distribution. CONCLUSIONS: DNA extraction methods had the highest impact on observed microbiome variability, and were comparable to interindividual differences, thus may spuriously mimic the microbiome signatures of various health and nutrition factors. Conversely, collection methods had a relatively small influence on microbiome composition. The present study provides necessary insight into the technical variables which can lead to divergent results from seemingly similar study designs. We anticipate that these results will contribute to future efforts towards standardization of microbiome quantification procedures in clinical research. TRANSLATIONAL PERSPECTIVES: By applying a framework which is typical for the investigation of the microbiome in cardiovascular disease patients, we assess the role of these confounders under realistic circumstances. Our work allows quality control and design improvement for upcoming translational microbiome studies such as the search for disease biomarkers or efficacy predictors for personalized treatment regimes

Medication Intake Is Associated with Lower Plasma Carotenoids and Higher Fat-Soluble Vitamins in the Cross-Sectional MARK-AGE Study in Older Individuals

The regular use of medication may interfere with micronutrient metabolism on several levels, such as absorption, turnover rate, and tissue distribution, and this might be amplified during aging. This study evaluates the impact of self-reported medication intake on plasma micronutrients in the MARK-AGE Project, a cross-sectional observational study in 2217 subjects (age- and sex-stratified) aged 35-75 years from six European countries that were grouped according to age. Polypharmacy as possible determinant of micronutrient concentrations was assessed using multiple linear regression models adjusted for age-group, dietary fruit, vegetables, and juice intake, and other confounders. Younger participants reported taking fewer drugs than older participants. Inverse associations between medication intake and lutein (-3.31% difference per increase in medication group), beta-carotene (-11.44%), alpha-carotene (-8.50%) and positive associations with retinol (+2.26%), alpha-tocopherol/cholesterol (+2.89%) and gamma-tocopherol/cholesterol (+1.36%) occurred in multiple adjusted regression models. Combined usage of a higher number of medical drugs was associated with poorer status of carotenoids on the one hand and higher plasma concentrations of retinol, alpha- and gamma-tocopherol on the other hand. Our results raise concerns regarding the safety of drug combinations via the significant and surprisingly multifaceted disturbance of the concentrations of relevant micronutrients

A robust machine learning framework to identify signatures for frailty: a nested case-control study in four aging European cohorts

Phenotype-specific omic expression patterns in people with frailty could provide invaluable insight into the underlying multi-systemic pathological processes and targets for intervention. Classical approaches to frailty have not considered the potential for different frailty phenotypes. We characterized associations between frailty (with/without disability) and sets of omic factors (genomic, proteomic, and metabolomic) plus markers measured in routine geriatric care. This study was a prevalent case control using stored biospecimens (urine, whole blood, cells, plasma, and serum) from 1522 individuals (identified as robust (R), pre-frail (P), or frail (F)] from the Toledo Study of Healthy Aging (R=178/P=184/F=109), 3 City Bordeaux (111/269/100), Aging Multidisciplinary Investigation (157/79/54) and InCHIANTI (106/98/77) cohorts. The analysis included over 35,000 omic and routine laboratory variables from robust and frail or pre-frail (with/without disability) individuals using a machine learning framework. We identified three protective biomarkers, vitamin D3 (OR: 0.81 [95% CI: 0.68–0.98]), lutein zeaxanthin (OR: 0.82 [95% CI: 0.70–0.97]), and miRNA125b-5p (OR: 0.73, [95% CI: 0.56–0.97]) and one risk biomarker, cardiac troponin T (OR: 1.25 [95% CI: 1.23–1.27]). Excluding individuals with a disability, one protective biomarker was identified, miR125b-5p (OR: 0.85, [95% CI: 0.81–0.88]). Three risks of frailty biomarkers were detected: pro-BNP (OR: 1.47 [95% CI: 1.27–1.7]), cardiac troponin T (OR: 1.29 [95% CI: 1.21–1.38]), and sRAGE (OR: 1.26 [95% CI: 1.01–1.57]). Three key frailty biomarkers demonstrated a statistical association with frailty (oxidative stress, vitamin D, and cardiovascular system) with relationship patterns differing depending on the presence or absence of a disability