An Increase in Vascular Stiffness is Positively Associated with Mitochondrial Bioenergetics Impairment of Peripheral Blood Mononuclear Cells in the Elderly Population

The cardio-ankle vascular index (CAVI) is a non-invasive parameter reflecting vascular stiffness. CAVI correlates with the burden of atherosclerosis and future cardiovascular events. Mitochondria of peripheral blood mononuclear cells (PBMCs) have been identified as a non-invasive source for assessing systemic mitochondrial bioenergetics. This study aimed to investigate the relationship between CAVI values and mitochondrial bioenergetics of PBMCs in the elderly population. This cross-sectional study enrolled participants from the Electricity Generating Authority of Thailand (EGAT) between 2017 and 2018. 1640 participants with an ankle-brachial index greater than 0.9 were included in this study. All participants were stratified into three groups based on their CAVI values as high (CAVI ≥9), moderate (9 >CAVI ≥8), and low (CAVI <8), in which each group comprised 702, 507 and 431 participants, respectively. The extracellular flux analyzer was used to measure mitochondrial respiration of isolated PBMCs. The mean age of the participants was 67.9 years, and 69.6% of them were male. After adjusted with potential confounders including age, sex, smoking status, body mass index, diabetes, dyslipidemia, hypertension, and creatinine clearance, participants with high CAVI values were independently associated with impaired mitochondrial bioenergetics, including decreased basal respiration, maximal respiration, and spare respiratory capacity, as well as increased mitochondrial reactive oxygen species. This study demonstrated that CAVI measurement reflects the underlying impairment of cellular mitochondrial bioenergetics in PBMCs. Further longitudinal studies are necessary to establish both a causal relationship between CAVI measurement and underlying cellular dysfunction.

Biological age as estimated by baseline circulating metabolites is associated with incident diabetes and mortality

OBJECTIVES

It is unclear how metabolomic assessment of biological aging performs in non-White populations and whether such an approach can predict future mortality. We aimed to evaluate the application of serum metabolomics combined with machine learning methodologies to predict incident diabetes and mortality in a Thai population.

DESIGN, SETTING AND PARTICIPANTS

We analyzed serum samples and mortality data over 11 years from among 454 participants with no previous history of diabetes and with a fasting plasma glucose ≥85th percentile (5.4 mmol/L) but <7 mmol/L.

MEASUREMENTS

Untargeted serum metabolomics were assessed using liquid chromatography/mass spectrometry. A deep artificial neural network was used to predict biological age based on serum metabolite profiles and chronological age.

RESULTS

The mean age of participants was 40.5 ± 6.4 years, and 70.8% were men. We found a significant positive correlation between metabolomic age and chronological age (r = 0.71, P < 0.001). After 5 years, 61 of 404 participants with available glycated hemoglobin status (15.1%) progressed to diabetes. Chronological age was associated with incident diabetes but was not significant (P = 0.08), after adjusting for BMI and sex. Metabolomic age was significantly related to incident diabetes after controlling for BMI and sex (P < 0.05). Over the 11-year follow-up, 10 participants died owing to non-accidental causes. When metabolomic age and chronological age were included together in the model, metabolomic age (but not chronological age) was associated with mortality, independent of age, sex, and BMI. Among all identifiable metabolites, beta-D-mannosylphosphodecaprenyl and phosphatidylserines were the five leading metabolites associated with mortality.

CONCLUSION

We concluded that serum metabolomic profile was associated with incident diabetes as well as mortality over our 11-year study period, which may render it potentially useful in assessing biological aging in humans.

Associations between residential greenness and air pollution and the incident metabolic syndrome in a Thai worker cohort

Increasing air pollution and decreasing exposure to greenness may contribute to the metabolic syndrome (MetS). We examined associations between long-term exposure to residential greenness and air pollution and MetS incidence in the Bangkok Metropolitan Region, Thailand. Data from 1369 employees (aged 52-71 years) from the Electricity Generating Authority of Thailand cohort from 2002 to 2017 were analyzed. The greenness level within 500 m of each participant's residence was measured using the satellite-derived Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI). The kriging approach was used to generate the average concentration of each air pollutant (PM10, CO, SO2, NO2, and O3) at the sub-district level. The average long-term exposure to air pollution and greenness for each participant was calculated over the same period of person-time. Cox proportional hazards models were used to analyze the greenness-air pollution-MetS associations. The adjusted hazard ratio of MetS was 1.42 (95% confidence interval (CI): 1.32, 1.53), 1.22 (95% CI: 1.15, 1.30), and 2.0 (95% CI: 1.82, 2.20), per interquartile range increase in PM10 (9.5 μg/m3), SO2 (0.9 ppb), and CO (0.3 ppm), respectively. We found no clear association between NDVI or EVI and the incidence of MetS. On the contrary, the incident MetS was positively associated with NDVI and EVI for participants exposed to PM10 at concentrations more than 50 μg/m3. In summary, the incidence of MetS was positively associated with long-term exposure to air pollution. In areas with high levels of air pollution, green spaces may not benefit health outcomes.

Longitudinal study of vitamin D status among Thai individuals in a sun-abundant country

Background

Vitamin D deficiency is a major public health problem worldwide, even in countries with abundant sunshine. Understanding the risk factors for vitamin D deficiency is important to inform public health recommendations. We conducted a longitudinal analysis of vitamin D status in Thai individuals to assess changes in vitamin D status over time and identify potential determinants.

Study design

This study is a long term prospective cohort study.

Methods

Of the 1239 participants who were employees of the Electricity Generating Authority of Thailand, serum 25-hydroxyvitamin D (25(OH)D) levels were measured by liquid chromatography/tandem mass spectrometry from samples collected in 2009 and 2019.

Results

There was a significant 14.8% increase in serum total 25(OH)D (P < 0.001) from 2009 to 2019, which resulted from significant increases in both 25(OH)D3 and 25(OH)D2. The epimeric form of 25(OH)D2 also increased significantly, while there was no increase in the epimeric form of 25(OH)D3. A univariate analysis showed significant associations between increased total 25(OH)D and increasing age, male sex, and lower body mass index. After controlling for baseline vitamin D status, multivariate regression analyses found that the direction of association and significance from univariate analyses persisted for total 25(OH)D and 25(OH)D3. However, a univariate association found between female sex and an increase in 25(OH)D2 was not significant in multivariate regression analysis.

Conclusions

A long-term trend of improved vitamin D status was found among Thai adult individuals over a 10-year period; however, improvements were less noticeable in women.

Residential greenness and kidney function: A cohort study of Thai employees

Higher residential greenness is associated with a lower risk of chronic kidney disease, but evidence on the association between greenness exposure and kidney function has not been conducted. Using cohort data from Electricity Generating Authority of Thailand (EGAT) employees, we investigated the association between long-term exposure to greenness and kidney function using estimated glomerular filtration rate (eGFR) in Bangkok Metropolitan Region (BMR), Thailand. We analyzed data from 2022 EGAT workers (aged 25-55 years at baseline) from 2009 to 2019. The level of greenness was calculated using the satellite-derived Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI). From 2008 to 2019, the average concentration of each air pollutant (PM₁₀, O₃, NO₂, SO₂, and CO) at the sub-district level in BMR was generated using the Kriging method. Long-term exposure for each participant was defined as the 1-year average concentrations before the date of the physical examination in 2009, 2014, and 2019. We employed linear mixed effects models to evaluate associations of NDVI and EVI with eGFR. The robustness of the results was also tested by including air pollutants in the models. After relevant confounders were controlled, the interquartile range increase in NDVI was associated with higher eGFR [1.03% (95%CI: 0.33, 1.74)]. After PM₁₀ and SO₂ were included in the models, the associations between NDVI and eGFR became weaker. The additions of O₃, NO₂, and CO strengthened the associations between them. In contrast, we did not find any association between EVI and eGFR. In conclusion, there was a positive association between NDVI and eGFR, but not for EVI. Air pollutants had a significant impact on the relationship between NDVI and eGFR. Additional research is needed to duplicate this result in various settings and populations to confirm our findings.

Increased Efficiency of Mitochondrial Coupling With a Reduction in Other Mitochondrial Respiratory Parameters in Peripheral Blood Mononuclear Cells Is Observed in Older Adults

Mitochondrial dysfunction is a factor potentially contributing to the Aging process. However, evidence surrounding changes in mitochondrial function and aging is still limited; therefore, this study aimed to investigate further the association between them. Possible confounding factors were included in the statistical analysis to explore the possibility of any independent associations. One thousand seven hundred and sixty-nine participants (619 middle-aged adults [age < 65] and 1,150 older adults [age ≥ 65]) from the Electricity Generating Authority of Thailand were enrolled in the study. The clinical characteristics and medical history were collected. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and used for analysis of mitochondrial function. Several parameters pertinent to mitochondrial respiration including non-mitochondrial respiration, basal respiration, maximal respiration, proton leak, and spare respiratory capacity were found to be two to three times lower in the mitochondria isolated from the cells of older adults. Interestingly, the mitochondrial ATP production was only slightly reduced, and the percentage of coupling efficiency of PBMC mitochondria was significantly higher in the older adult group. The mitochondrial mass and oxidative stress were significantly reduced in older adult participants; however, the ratio of oxidative stress to mass was significantly increased. The association of these parameters with age was still shown to be the same from the outcome of the multivariate analyses. The mitochondrial functions and mitochondrial mass in PBMCs were shown to decline in association with age. However, the upregulation of mitochondrial oxidative stress production and mitochondrial coupling efficiency might indicate a compensatory response in mitochondria during aging.

Targeted metabolomics suggests a probable role of the FTO gene in the kynurenine pathway in prediabetes

Background

Genome-wide association studies have identified the alpha-ketoglutarate dependent dioxygenase gene (FTO) as the first susceptibility gene of obesity. In the present study, we utilized targeted metabolomics in an attempt to further elucidate mechanisms underlying the action of the FTO gene.

Methods

This study was part of a health survey of employees of the Electricity Generating Authority of Thailand (n = 79, 10 female and 69 male). Targeted metabolomics was performed by liquid chromatography-mass spectrometry using Biocrates AbsoluteIDQ-p180 kit. Genotyping of FTO rs9939609 was performed by real-time PCR (TaqMan™ MGB probes).

Results

Using OPLS-DA variable importance in projection (VIP), tryptophan was found to be among the metabolites with the 10 highest VIP scores. Pearson's correlation analysis showed that kynurenine and tryptophan were positively correlated only in subjects with the rs9939609 A allele (n = 32, r = 0.56, p < 0.001) and the correlation coefficients were significantly higher in subjects having the A allele than in those without the A allele (p < 0.05). Moreover, the kynurenine/tryptophan ratio was significantly associated with the presence of the A allele, independently of body mass index and sex.

Conclusions

The FTO gene is likely to influences the conversion of tryptophan to kynurenine.

Long-term air pollution exposure and decreased kidney function: A longitudinal cohort study in Bangkok Metropolitan Region, Thailand from 2002 to 2012

BACKGROUND

Kidney dysfunction is considered a cardiovascular risk factor. However, few longitudinal studies have examined the effects of air pollution on kidney function. We evaluated associations between long-term air pollution exposure and estimated glomerular filtration rate (eGFR) using data from a cohort of the Electricity Generating Authority of Thailand (EGAT) study in Bangkok Metropolitan Region, Thailand.

METHODS

This longitudinal study included 1839 subjects (aged 52-71 years in 2002) from the EGAT1 cohort study during 2002-2012. eGFR, based on creatinine, was measured in 2002, 2007, and 2012. Annual mean concentrations of air pollutants (i.e., particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO)) prior to a measurement of creatinine were assessed with the ordinary kriging method. Mixed-effect linear regression models were used to assess associations between air pollutants and eGFR, while controlling for potential covariates. eGFR values are expressed as percent change per interquartile range (IQR) increments of each pollutant.

RESULTS

Lower eGFR was associated with higher concentrations of PM₁₀ (-1.99%, 95% confidence interval (CI): -3.33, -0.63), SO₂ (-4.89%, 95%CI: -6.69, -3.07), and CO (-0.97%, 95%CI: -1.96, 0.03). However, after adjusting for temperature, relative humidity, PM₁₀, and SO₂, no significant association was observed between CO and eGFR.

CONCLUSIONS

Our findings support the hypothesis that long-term exposure to high concentrations of PM₁₀ and SO₂ is associated with the progression of kidney dysfunction in subjects of the EGAT cohort study.

Herbal or traditional medicine consumption in a Thai worker population: pattern of use and therapeutic control in chronic diseases

Background

Herbal and traditional medicines (HTM) are widely used in Asian countries. Specific data on prevalent of HTM usage and association with chronic diseases in the Thai population is currently lacking. We examined the prevalence and factors associated with HTM use in a Thai worker population. In addition, we explored the relationship between HTM use and therapeutic control of cardiovascular risk factors and documented the most common types of HTM used in various chronic diseases.

Methods

Employees of EGAT (The Electric Generating Authority of Thailand) who had participated in a health examination were studied. Each participant documented their HTM consumption and self-reported chronic diseases in a questionnaire. Clinical disease and therapeutic control were also defined by concomitant laboratory tests.

Results

Of a total of 6592 subjects, 32.6% were HTM-users. Age < 50 years, female gender, self-reported history of diabetes, liver disease, cancer, dyslipidemia, and alcohol use were independently associated with HTM use. HTM consumption increased in proportion to the numbers of self-reported chronic diseases. There were no differences in the therapeutic control of cardiovascular risk factors between HTM users and non-users. Liver and kidney function were not different. The most commonly used HTM was turmeric.

Conclusions

HTM consumption is common in community-based Thai subjects, with higher use among those with chronic diseases. Although there were no differences in control of cardiovascular risk factors between HTM users and non-users, many of the commonly used herbs have relevant biological activities for chronic disease prevention or treatment.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2652-z) contains supplementary material, which is available to authorized users.

Risk scores to predict decreased glomerular filtration rate at 10 years in an Asian general population

Background

Asians have among the highest prevalence of chronic kidney disease (CKD) or end-stage renal disease in the world. A risk score capable of identifying high risk individuals at the primary care level could allow targeted therapy to prevent future development of CKD. Risk scores for new CKD have been developed in US general populations, but the impact of various risks factors for development of CKD may differ in Asian subjects. In this study, we aimed to develop risk models and simplified risk scores to predict the development of decreased glomerular filtration rate (GFR) at 10 years in an Asian general population using readily obtainable clinical and laboratory parameters.

Methods

Employees of EGAT (The Electric Generating Authority of Thailand) were studied prospectively. Multivariable logistic regression models were used to assess risk factors and used to derive risk models and risk scores for developing decreased GFR at 10 years: Model 1 (Clinical only), Model 2 (Clinical + Limited laboratory tests), and Model 3 (Clinical + Full laboratory tests). The performance of the risk models or risk scores to predict incident cases with decreased GFR were evaluated by tests of calibration and discrimination.

Results

Of 3186 subjects with preserved GFR (eGFR ≥60) at baseline, 271 (8.5%) developed decreased GFR (eGFR < 60) at 10 years. Model 1 (Age, sex, systolic blood pressure, history of diabetes, and waist circumference) had good performance (χ² = 9.02; AUC = 0.72). Model 2 (Age, Sex, systolic blood pressure, diabetes, glomerular filtration rate) had better discrimination (χ² = 10.87, AUC = 0.79) than Model 1. Model 3 (Model 2+ Uric acid, Hemoglobin) did not provide significant improvement over Model 2. Based on these findings, simplified categorical risk scores were developed for Models 1 and 2.

Conclusions

Clinical or combined clinical and laboratory risk models or risk scores using tests readily available in a resource-limited setting had good accuracy and discrimination power to estimate the 10-year probability of developing decreased GFR in a Thai general population. The benefits of the risk scores in identifying high risk individuals in the Thai or other Asian communities for special intervention requires further studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0653-z) contains supplementary material, which is available to authorized users.