Anemia is associated with long-term exposure to PM2.5 and its components: a large population-based study in Southwest China

Effects of PM2.5 exposure on hematopoiesis and coupled immune disorder in adult male mice

Fine particulate matter, namely PM2.5, increases the risk of morbidity and mortality in various systems, including the hematopoietic and immune systems. However, there is limited experimental evidence supporting the association between PM2.5 exposure and hematopoietic outcomes as most studies focus on epidemiological data. In this study, adult male mice were exposed to PM2.5 for a long time to investigate hematopoietic toxicity. There were significant increases in red blood cells (RBC), hemoglobin (HGB), and white blood cells (WBC) in peripheral blood after 5-month real-environmental PM2.5 exposure, indicating elevated circulatory inflammation and potential hematopoietic abnormality. Moreover, we observed abnormal proliferation and differentiation of hematopoietic stem and progenitor cells (HSPCs), along with altered mRNA levels of hematopoietic genes and increased proinflammatory factors in the bone marrow (BM). Transcriptomic analysis of BM cells suggested that PM2.5 exposure activated immune responses associated with lymphocytes. Then, PM2.5 exposure via intratracheal instillation was performed for 8 weeks to verify the toxic effect. The results of the complete blood count were similar to those of real-environmental exposure, with drastic changes in the number and function of HSPCs, as well as mRNA levels of the hematopoietic genes and increased inflammatory factors in the BM being detected. Furthermore, lymphocyte subsets changed significantly in the BM and spleen, confirming immune disorder following PM2.5 exposure. In conclusion, PM2.5 interfered with the process of BM hematopoiesis by triggering inflammation and leading to immune disorder. Our study provided experimental evidence for the hematopoietic toxicity of PM2.5 and highlighted the significance of reducing air pollution.

Colemanite and Biological Disruptions: Behavioral, Neurological, and Physiological Findings

Colemanite (COL), a boron-containing mineral, has shown potential therapeutic applications, particularly in the fields of drug delivery and bone health. However, despite its promising bioactive properties, there is a lack of comprehensive toxicological data on its safety, especially regarding its potential medical use. Previous studies have primarily focused on its industrial applications, with limited investigation into its biological effects. This gap in knowledge prompted the current study, which aimed to investigate the subacute toxicity of colemanite in rats using behavioral, hematological, biochemical, genotoxic, and histopathological analyses. Over a 7-day period, rats were treated with doses of 10, 30, and 300 mg/kg. Behavioral assessments, including locomotor activity and elevated plus maze tests, indicated enhanced exploratory behaviors, indicating heightened curiosity or activity and no alterations in motor coordination or anxiety-like behaviors. Hematological findings revealed dose-dependent reductions in hematocrit, hemoglobin, and red blood cell counts, while biochemical analyses showed elevated aspartate aminotransferase, lactate dehydrogenase, and cholesterol levels at higher doses, suggesting hepatotoxicity and lipid metabolism disruption. Genotoxicity analysis demonstrated increased micronucleus formation at 30 and 300 mg/kg, indicative of chromosomal instability possibly linked to oxidative stress. Histopathological evaluations revealed mild hepatocyte degeneration and hyperemia in the liver and brain tissues at the highest dose. Importantly, no significant toxic effects were observed at the 10 mg/kg dose. These findings highlight the dose-dependent toxicity of colemanite, with low doses exhibiting a favorable safety profile. This study underscores the need for dose optimization and further research to elucidate the molecular mechanisms underlying colemanite's toxicological effects, including its impact on various organs over both short-term and long-term exposures. Additionally, future studies should focus on assessing the human relevance of these effects to ensure its safe and effective therapeutic application.

Machine learning identifies routine blood tests as accurate predictive measures of pollution-dependent poor cognitive function

Background

Several modifiable risk factors for dementia and related neurodegenerative diseases have been identified including education level, socio-economic status, and environmental exposures - however, how these population-level risks relate to individual risk remains elusive. To address this, we assess over 450 potential risk factors in one deeply clinically and demographically phenotyped cohort using random forest classifiers to determine predictive markers of poor cognitive function. This study aims to understand early risk factors for dementia by identifying predictors of poor cognitive performance amongst a comprehensive battery of imaging, blood, atmospheric pollutant and socio-economic measures.

Methods

Random forest modelling was used to determine significant predictors of poor cognitive performance in a cohort of 324 individuals (age 61.6 ± 4.8 years; 150 males, 174 females) without extant neurological disease. 457 features were assessed including brain imaging measures of volume and iron deposition, blood measures of anaemia, inflammation, and heavy metal levels, social deprivation indicators and atmospheric pollution exposure.

Results

Routinely assessed markers of anaemia including mean corpuscular haemoglobin concentration were identified as robust predictors of poor general cognition, where both extremes (low and high) were associated with poor cognitive performance. The strongest, most consistent predictors of poor cognitive performance were environmental measures of atmospheric pollution, in particular, lead, carbon monoxide, and particulate matter. Feature analysis demonstrated a significant negative relationship between low mean corpuscular haemoglobin concentration and high levels of atmospheric pollutants highlighting the potential of routinely assessed blood tests as a predictive measure of pollution-dependent cognitive functioning, at an individual level.

Conclusions

Taken together, these data demonstrate how routine, inexpensive medical testing and local authority initiatives could help to identify and protect at-risk individuals. These findings highlight the potential to identify individuals for targeted, cost effective medical and social interventions to improve population cognitive health.

Exposure to air pollution as a risk factor for anaemia: a global scoping review

Anaemia is an important global health issue with various factors responsible for its occurrence. Though nutritional deficiency is one of the main causes of the disease, evidence suggests a potential link between long-term exposure to ambient air pollution and an increased risk of developing anaemia. Our scoping review evaluates studies conducted across the world to examine possible associations between anaemia and ambient air pollution. Six databases were searched, 153 sources were identified, and 21 articles were included in the review. Apart from one article which showed no significant effect, studies reported positive associations between anaemia and air pollution. This was true for both indoor and outdoor air pollution, various types of particulate matter exposure, and across demographic groups. The review highlights the importance of recognizing exposure to air pollution as a potential risk factor for anaemia and emphasizes the imperative for focused interventions and policy measures to mitigate air pollution.

Burden of Child Anemia Attributable to Fine Particulate Matters Brought by Sand Dusts in Low- and Middle-Income Countries

Addressing environmental factors has recently been recommended to curb the growing trend of anemia in low- and middle-income countries (LMICs). Fine particulate matter (PM2.5) generated by dust storms were concentrated in place with a high prevalence of anemia. In a multicounty, multicenter study, we analyzed the association between anemia and life-course averaged exposure to dust PM2.5 among children aged <5 years based on 0.65 million records from 47 LMICs. In the fully adjusted mixed effects model, each 10 μg/m3 increase in life-course averaged exposure to dust PM2.5 was associated with a 9.3% increase in the odds of anemia. The estimated exposure-response association was nonlinear, with a greater effect of dust PM2.5 exposure seen at low concentrations. Applying this association, we found that, in 2017, among all children aged <5 years in the 125 LMICs, dust PM2.5 contributed to 37.98 million cases of anemia. Results indicated that dust PM2.5 contributed a heavier burden than all of the well-identified risk factors did, except for iron deficiency. Our study revealed that long-term exposure to dust PM2.5 can be a novel risk factor, pronouncedly contributed to the burden of child anemia in LMICs, affected by land degradations or arid climate.