Ribosomal DNA copy number associated with blood metal levels in school-age children: A follow-up study on a municipal waste incinerator in Zhejiang, China.

To evaluate the body burdens of heavy metals and explore the impact of environmental metal exposure on ribosomal DNA (rDNA) or mitochondrial DNA (mtDNA) copy number (CN) variation in school-age children living near a municipal waste incinerator (MWI), we conducted a follow-up study in 2019. A total of 146 sixth-grade children from a primary school located 1.2 km away from the MWI were recruited for our study. Metals, including vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), stannum (Sn), stibium (Sb), thallium (Tl), and lead (Pb), were determined by an inductively coupled plasma mass spectrometer method. Real-time qPCR was used to measure the rDNA and mtDNA CN. The blood metal levels followed this order: Zn > Cu > Se > Pb > Mn > Sb > As > Ni > Cd > Co > Cr > Sn > V > Tl. Blood Cr level was significantly correlated with 18 S, 2.5 S, and 45 S CN (ß = -0.25, -0.22, -0.26, p < 0.05); Ni was correlated with 5 S (ß = -0.36, p < 0.01); Cu was correlated with 28 S, 18 S, and 5.8 S (ß = -0.24, -0.24, -0.23, p < 0.05); while Zn was correlated with 18 S, 5.8 S, and 45 S (ß = -0.28, -0.32, -0.26, p < 0.05). In conclusion, school-age children living near the MWI had lower blood metal levels compared to children recruited in 2013, while rDNA CN loss was found to be correlated to several heavy metals in these children.

Serum apolipoprotein A-I depletion is causative to silica nanoparticles-induced cardiovascular damage.

The rapid development of nanotechnology has greatly benefited modern science and engineering and also led to an increased environmental exposure to nanoparticles (NPs). While recent research has established a correlation between the exposure of NPs and cardiovascular diseases, the intrinsic mechanisms of such a connection remain unclear. Inhaled NPs can penetrate the air-blood barrier from the lung to systemic circulation, thereby intruding the cardiovascular system and generating cardiotoxic effects. In this study, on-site cardiovascular damage was observed in mice upon respiratory exposure of silica nanoparticles (SiNPs), and the corresponding mechanism was investigated by focusing on the interaction of SiNPs and their encountered biomacromolecules en route. SiNPs were found to collect a significant amount of apolipoprotein A-I (Apo A-I) from the blood, in particular when the SiNPs were preadsorbed with pulmonary surfactants. While the adsorbed Apo A-I ameliorated the cytotoxic and proinflammatory effects of SiNPs, the protein was eliminated from the blood upon clearance of the NPs. However, supplementation of Apo A-I mimic peptide mitigated the atherosclerotic lesion induced by SiNPs. In addition, we found a further declined plasma Apo A-I level in clinical silicosis patients than coronary heart disease patients, suggesting clearance of SiNPs sequestered Apo A-I to compromise the coronal protein's regular biological functions. Together, this study has provided evidence that the protein corona of SiNPs acquired in the blood depletes Apo A-I, a biomarker for prediction of cardiovascular diseases, which gives rise to unexpected toxic effects of the nanoparticles.

[Studies on effect enhancement of the Schistosoma japonicum DNA vaccine pVIV02-IL12-Sj23 by vegetal polysaccharides].

OBJECTIVE: To enhance the immunogenicity of the recombinant pVIVO2-IL12-Sj23 vaccine of Schistosoma japonicum by using mixed vegetal polysaccharides as adjuvant. METHODS: The plasmid pVIVO2-IL12-Sj23 was constructed. 3 groups of BALB/C mice were injected intramuscularly with normal saline (Group A), pVIVO2-IL12-Sj23 plasmid DNA (B), and pVIVO2-IL12-Sj23 plus mixed vegetal polysaccharides (C) respectively, and challenged with S. japonicum cercariae on the 4th week after immunization. Mice were killed to calculate the worm reduction rate and egg reduction rate in liver tissue on the 6th week after infection. Before and 4 weeks after immunization blood samples were collected. RESULTS: The worm reduction rate and egg reduction rate were 64.3% and 79.9%, respectively in group C, 45.5% and 58.4%, respectively in group B, showing a remarkable difference hetween them (P < 0.05). ELISA analysis showed a significantly higher level of IgG specific for Sj23 4 weeks after vaccination in groups B and C (P < 0.05). However, there was no significant difference in IgG level between groups C and B (P > 0.05). CONCLUSION: When mixed vegetal polysaccharides are used as adjuvant, the effect of the vaccine pVIVO2-IL12-Sj23 can he considerably enhanced.