[A panel study on the effect of atmospheric PM2.5 exposure on the gut microbiome in healthy elderly people aged 60-69 years old].

Objective: To analyze the short-term effect of individual atmospheric PM2.5 exposure on the diversity, enterotype, and community structure of gut microbiome in healthy elderly people in Jinan, Shandong province. Methods: The present panel study recruited 76 healthy elderly people aged 60-69 years old in Dianliu Street, Lixia District, Jinan, Shandong Province, and followed them up five times from September 2018 to January 2019. The relevant information was collected by questionnaire, physical examination, precise monitoring of individual PM2.5 exposure, fecal sample collection and gut microbiome 16S rDNA sequencing. The Dirichlet multinomial mixtures (DMM) model was used to analyze the enterotype. Linear mixed effect model and generalized linear mixed effect model were used to analyze the effect of PM2.5 exposure on gut microbiome α diversity indices (Shannon, Simpson, Chao1, and ACE indices), enterotype and abundance of core species. Results: Each of the 76 subjects participated in at least two follow-up visits, resulting in a total of 352 person-visits. The age of 76 subjects was (65.0±2.8) years old with BMI (25.0±2.4) kg/m2. There were 38 males accounting for 50% of the subjects. People with an educational level of primary school or below accounted for 10.5% of the 76 subjects, and those with secondary school and junior college or above accounting for 71.1% and 18.4%. The individual PM2.5 exposure concentration of 76 subjects during the study period was (58.7±53.7) µg/m3. DMM model showed that the subjects could be divided into four enterotypes, which were mainly driven by Bacteroides, Faecalibacterium, Lachnospiraceae, Prevotellaceae, and Ruminococcaceae. Linear mixed effects model showed that different lag periods of PM2.5 exposure were significantly associated with a lower gut α diversity index (FDR<0.05 after correction). Further analysis showed that PM2.5 exposure was significantly associated with changes in the abundances of Firmicutes (Megamonas, Blautia, Streptococcus, etc.) and Bacteroidetes (Alistipes) (FDR<0.05 after correction). Conclusion: Short-term PM2.5 exposure is significantly associated with a decrease in gut microbiome diversity and changes in the abundance of several species of Firmicutes and Bacteroidetes in the elderly. It is necessary to further explore the underlying mechanisms between PM2.5 exposure and the gut microbiome, so as to provide a scientific basis for promoting the intestinal health of the elderly.

[Developmental effects of TCIPP and TnBP on zebrafish (Danio rerio) embryos].

Objective: To investigate the toxicity of tris (2-chloropropyl) phosphate (TCIPP) and tributyl phosphate (TnBP) on the growth and development of zebrafish embryos, as well as to explore the underlying mechanisms at the transcriptional level. Methods: With zebrafish as a model, two hpf zebrafish embryos were exposed to TCIPP and TnBP (0.1, 1, 10, 100, 500, and 1 000 µmol/L) using the semi-static method, and their rates of lethality and hatchability were determined. The transcriptome changes of 120 hpf juvenile zebrafish exposed to environmentally relevant concentrations of 0.1 and 1 µmol/L were measured. Results: The 50% lethal concentrations (LC50) of TCIPP and TnBP for zebrafish embryos were 155.30 and 27.62 µmol/L (96 hpf), 156.5 and 26.05 µmol/L (120 hpf), respectively. The 72 hpf hatching rates of TCIPP (100 µmol/L) and TnBP (10 µmol/L) were (23.33±7.72)% and (91.67±2.97)%, which were significantly decreased compared with the control group (P<0.05). Transcriptome analysis showed that TnBP had more differential genes (DEGs) than TCIPP, with a dose-response relationship. These DEGs were enriched in 32 pathways in total, including those involved in oxidative stress, energy metabolism, lipid metabolism, and nuclear receptor-related pathways, using the IPA pathway analysis. Among them, three enriched pathways overlapped between TCIPP and TnBP, including TR/RXR activation and CAR/RXR activation. Additionally, DEGs were also mapped onto pathways of LXR/RXR activation and oxidative stress for TnBP exposure only. Conclusion: Both TCIPP and TnBP have growth and developmental toxicities in zebrafish embryos, with distinct biomolecular mechanisms, and TnBP has a stronger effect than TCIPP.

[Comparative analysis of metagenomic and 16S rDNA sequencing in gut microbiota of healthy elderly].

Objective: To explore the differences in subsequent analysis between metagenomic and 16Sr DNA sequencing in compositionally characterizing gut microbiota of healthy elderly. Methods: By using a panel study design, five monthly repeated measurements were performed among 76 healthy older people in Jinan City, Shandong Province. Their fecal samples were collected, and genomic DNA was extracted and analyzed through metagenomic and 16Sr DNA sequencing to compare the composition and diversity of gut microbiota. The correlation between species abundance and α diversity was analyzed by Pearson correlation analysis, and the correlation between species abundance and ß diversity was determined by Procrustes analysis. Results: The age of 76 participants was (65.07±2.75), and the body mass index was (25.03±2.40) kg/m2. There were 38 males and 38 females. A total of 345 fecal samples were obtained from five monthly repeated measurements. Compared with 16S rDNA sequencing, metagenomic sequencing showed more annotated species at each level. The difference in the number of two sequencing species increased with the decrease of the level. Although there were significant differences in species richness between the two sequencing methods. Their species richness was highly correlated at both phylum (r=0.88, P<0.001) and genus (r=0.77, P<0.001) levels. Bacteroidetes and Firmicutes were the common dominant species. Gut microbiota diversity analysis further showed that there was a significantly positive correlation between α diversity (r=0.70, P<0.001) and ß diversities (M2=0.84, P<0.05) in the two groups. Conclusion: The annotation efficiency of metagenomic sequencing is much higher than that of 16S rDNA sequencing. The two sequencing methods are consistent in phylum abundance as well as α diversity.

[Associations between personal fine particulate matter and blood lipid profiles: A panel study in Chinese people aged 60-69 years].

Objective: To explore the association between short-term exposures to fine particulate matter (PM2.5) on blood lipids in the elderly. Methods: In this panel study, five repeated measurements were performed on 76 people aged 60-69 in Jinan city. Each participant had a PM2.5 monitor for 72 hours before each health examination, including a questionnaire survey, physical examination, and biological sample collection. Serum triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were examined, and non-HDL-C concentrations were calculated by subtracting HDL-C from TC. The generalized linear mixed-effects model was used to quantify the association of personal PM2.5 exposure at different lag with blood lipids and dyslipidemia. Results: The age of 70 participants was (65.0±2.8) years, of which 48.6% (34/70) were males. The BMI of participants was (25.0±2.5) kg/m2. Their TC, TG, LDL-C, HDL-C, and non-HDL-C concentrations were (5.75±1.32), (1.55±0.53), (3.27±0.94), (1.78±0.52), and (3.97±1.06) mmol/L, respectively. Generalized linear mixed-effects model showed that after adjusting for confounding factors, at lag 72 hours, each 10 µg/m3 increase in PM2.5 was associated with the percentage change in TC, LDL-C, HDL-C and non-HDL-C about 1.77% (95%CI: 1.22%-2.32%), 1.90% (95%CI: 1.18%-2.63%), 1.99% (95%CI: 1.37%-2.60%) and 1.74% (95%CI: 1.11%-2.37%), and the OR values (95%CI) of hypercholesterolemia, hypertriglyceridemia and hyperbetalipoproteinemia were 1.11 (1.01-1.22), 1.33 (1.03-1.71) and 1.15 (1.01-1.31), respectively. Conclusion: There is a significant association of short-term PM2.5 exposure with the concentration of blood lipids and the risk of dyslipidemia in the elderly.

[Research advances in the adverse effects of azo dyes].

China is the world's largest producer and user of dyes. The mass production and widespread use of disperse azo dyes led to environmental pollutions and potential human health risks. Azo dyes in environmental media (i.e., water, soil, air, and dust), food and clothing can enter the human body through multiple exposure routes, and some of them can be metabolized to produce more toxic metabolites, which can trigger toxic effects such as allergic reactions, tumor formation, and endocrine disruptions. This study systematically reviewed the production and use of azo dyes, environmental concentrations, human exposures, toxic effects and their underlying mechanisms, and regulations and standards. Meanwhile, the research trends of azo dyes were also discussed.