Reduction of Outdoor and Indoor PM2.5 Source Contributions via Portable Air Filtration Systems in a Senior Residential Facility in Detroit, Michigan

Background: The Reducing Air Pollution in Detroit Intervention Study (RAPIDS) was designed to evaluate cardiovascular health benefits and personal fine particulate matter (particulate matter < 2.5 μm in diameter, PM2.5) exposure reductions via portable air filtration units (PAFs) among older adults in Detroit, Michigan. This double-blind randomized crossover intervention study has shown that, compared to sham, air filtration for 3 days decreased 3-day average brachial systolic blood pressure by 3.2 mmHg. The results also showed that commercially available HEPA-type and true HEPA PAFs mitigated median indoor PM2.5 concentrations by 58% and 65%, respectively. However, to our knowledge, no health intervention study in which a significant positive health effect was observed has also evaluated how outdoor and indoor PM2.5 sources impacted the subjects. With that in mind, detailed characterization of outdoor and indoor PM2.5 samples collected during this study and a source apportionment analysis of those samples using a positive matrix factorization model were completed. The aims of this most recent work were to characterize the indoor and outdoor sources of the PM2.5 this community was exposed to and to assess how effectively commercially available HEPA-type and true HEPA PAFs were able to reduce indoor and outdoor PM2.5 source contributions. Methods: Approximately 24 h daily indoor and outdoor PM2.5 samples were collected on Teflon and Quartz filters from the apartments of 40 study subjects during each 3-day intervention period. These filters were analyzed for mass, carbon, and trace elements. Environmental Protection Agency Positive Matrix Factorization (PMF) 5.0 was utilized to determine major emission sources that contributed to the outdoor and indoor PM2.5 levels during this study. Results: The major sources of outdoor PM2.5 were secondary aerosols (28%), traffic/urban dust (24%), iron/steel industries (15%), sewage/municipal incineration (10%), and oil combustion/refinery (6%). The major sources of indoor PM2.5 were organic compounds (45%), traffic + sewage/municipal incineration (14%), secondary aerosols (13%), smoking (7%), and urban dust (2%). Infiltration of outdoor PM2.5 for sham, HEPA-type, and true HEPA air filtration was 79 ± 24%, 61 ± 32%, and 51 ± 34%, respectively. Conclusions: The results from our study showed that intervention with PAFs was able to significantly decrease indoor PM2.5 derived from outdoor and indoor PM2.5 sources. The PAFs were also able to significantly reduce the infiltration of outdoor PM2.5. The results of this study provide insights into what types of major PM2.5 sources this community is exposed to and what degree of air quality and systolic blood pressure improvements are possible through the use of commercially available PAFs in a real-world setting.

Neuroinflammatory and Neurometabolomic Consequences From Inhaled Wildfire Smoke-Derived Particulate Matter in the Western United States

Utilizing a mobile laboratory located >300 km away from wildfire smoke (WFS) sources, this study examined the systemic immune response profile, with a focus on neuroinflammatory and neurometabolomic consequences, resulting from inhalation exposure to naturally occurring wildfires in California, Arizona, and Washington in 2020. After a 20-day (4 h/day) exposure period in a mobile laboratory stationed in New Mexico, WFS-derived particulate matter (WFPM) inhalation resulted in significant neuroinflammation while immune activity in the peripheral (lung, bone marrow) appeared to be resolved in C57BL/6 mice. Importantly, WFPM exposure increased cerebrovascular endothelial cell activation and expression of adhesion molecules (VCAM-1 and ICAM-1) in addition to increased glial activation and peripheral immune cell infiltration into the brain. Flow cytometry analysis revealed proinflammatory phenotypes of microglia and peripheral immune subsets in the brain of WFPM-exposed mice. Interestingly, endothelial cell neuroimmune activity was differentially associated with levels of PECAM-1 expression, suggesting that subsets of cerebrovascular endothelial cells were transitioning to resolution of inflammation following the 20-day exposure. Neurometabolites related to protection against aging, such as NAD+ and taurine, were decreased by WFPM exposure. Additionally, increased pathological amyloid-beta protein accumulation, a hallmark of neurodegeneration, was observed. Neuroinflammation, together with decreased levels of key neurometabolites, reflect a cluster of outcomes with important implications in priming inflammaging and aging-related neurodegenerative phenotypes.

Catalytic activity of Co-nanocrystal-doped tungsten carbide arising from an internal magnetic field

Pt is an excellent and widely used hydrogen evolution reaction (HER) catalyst. However, it is a rare and expensive metal, and alternative catalysts are being sought to facilitate the hydrogen economy. As tungsten carbide (WC) has a Pt-like occupied density of states, it is expected to exhibit catalytic activity. However, unlike Pt, excellent catalytic activity has not yet been observed for mono WC. One of the intrinsic differences between WC and Pt is in their magnetic properties; WC is non-magnetic, whereas Pt exhibits high magnetic susceptibility. In this study, the WC lattice was doped with ferromagnetic Co nanocrystals to introduce an ordered-spin atomic configuration. The catalytic activity of the Co-doped WC was ∼30% higher than that of Pt nanoparticles for the HER during the hydrolysis of ammonia borane (NH₃BH₃), which is currently attracting attention as a hydrogen fuel source. Measurements of the magnetisation, enthalpy of adsorption, and activation energy indicated that the synergistic effect of the WC matrix promoting hydrolytic cleavage of NH₃BH₃ and the ferromagnetic Co crystals interacting with the nucleus spin of the protons was responsible for the enhanced catalytic activity. This study presents a new catalyst design strategy based on the concept of an internal magnetic field. The WC–Co material presented here is expected to have a wide range of applications as an HER catalyst.

The catalytic activity of the Co-doped WC is 30% higher than that of Pt nanoparticles for the hydrogen evolution reaction arising from an internal magnetic field.

Assessment of particulate matter toxicity and physicochemistry at the Claim 28 uranium mine site in Blue Gap, AZ

Thousands of abandoned uranium mines (AUMs) exist in the western United States. Due to improper remediation, windblown dusts generated from AUMs are of significant community concern. A mobile inhalation lab was sited near an AUM of high community concern ("Claim 28") with three primary objectives: to (1) determine the composition of the regional ambient particulate matter (PM), (2) assess meteorological characteristics (wind speed and direction), and (3) assess immunological and physiological responses of mice after exposures to concentrated ambient PM (or CAPs). C57BL/6 and apolipoprotein E-null (ApoE^-/-) mice were exposed to CAPs in AirCARE1 located approximately 1 km to the SW of Claim 28, for 1 or 28 days for 4 hr/day at approximately 80 µg/m³ CAPs. Bronchoalveolar lavage fluid (BALF) analysis revealed a significant influx of neutrophils after a single-day exposure in C57BL/6 mice (average PM_2.5 concentration = 68 µg/m³). Lungs from mice exposed for 1 day exhibited modest increases in Tnfa and Tgfb mRNA levels in the CAPs exposure group compared to filtered air (FA). Lungs from mice exposed for 28 days exhibited reduced Tgfb (C57BL/6) and Tnfa (ApoE^-/-) mRNA levels. Wind direction was typically moving from SW to NE (away from the community) and, while detectable in all samples, uranium concentrations in the PM_2.5 fraction were not markedly different from published-reported values. Overall, exposure to CAPs in the region of the Blue GAP Tachee's Claim-28 uranium mine demonstrated little evidence of overt pulmonary injury or inflammation or ambient air contamination attributed to uranium or vanadium.

Serum-borne factors alter cerebrovascular endothelial microRNA expression following particulate matter exposure near an abandoned uranium mine on the Navajo Nation

Background

Commercial uranium mining on the Navajo Nation has subjected communities on tribal lands in the Southwestern United States to exposures from residual environmental contamination. Vascular health effects from these ongoing exposures are an active area of study. There is an association between residential mine-site proximity and circulating biomarkers in residents, however, the contribution of mine-site derived wind-blown dusts on vascular and other health outcomes is unknown. To assess neurovascular effects of mine-site derived dusts, we exposed mice using a novel exposure paradigm, the AirCARE1 mobile inhalation laboratory, located 2 km from an abandoned uranium mine, Claim 28 in Blue Gap Tachee, AZ. Mice were exposed to filtered air (FA) (n = 6) or concentrated ambient particulate matter (CAPs) (n = 5) for 2 wks for 4 h per day.

Results

To assess miRNA differential expression in cultured mouse cerebrovascular cells following particulate matter (PM) exposure (average: 96.6 ± 60.4 μg/m³ for all 4 h exposures), the serum cumulative inflammatory potential (SCIP) assay was employed. MiRNA sequencing was then performed in cultured mouse cerebrovascular endothelial cells (mCECs) to evaluate transcriptional changes. Results indicated 27 highly differentially expressed (p < 0.01) murine miRNAs, as measured in the SCIP assay. Gene ontology (GO) pathway analysis revealed notable alterations in GO enrichment related to the cytoplasm, protein binding and the cytosol, while significant KEGG pathways involved pathways in cancer, axon guidance and Wnt signaling. Expression of these 27 identified, differentially expressed murine miRNAs were then evaluated in the serum. Nine of these miRNAs (~ 30%) were significantly altered in the serum and 8 of those miRNAs demonstrated the same directional change (either upregulation or downregulation) as cellular miRNAs, as measured in the SCIP assay. Significantly upregulated miRNAs in the CAPs exposure group included miRNAs in the let-7a family. Overexpression of mmu-let-7a via transfection experiments, suggested that this miRNA may mediate mCEC barrier integrity following dust exposure.

Conclusions

Our data suggest that mCEC miRNAs as measured in the SCIP assay show similarity to serum-borne miRNAs, as approximately 30% of highly differentially expressed cellular miRNAs in the SCIP assay were also found in the serum. While translocation of miRNAs via exosomes or an alternative mechanism is certainly possible, other yet-to-be-identified factors in the serum may be responsible for significant miRNA differential expression in endothelium following inhaled exposures. Additionally, the most highly upregulated murine miRNAs in the CAPs exposure group were in the let-7a family. These miRNAs play a prominent role in cell growth and differentiation and based on our transfection experiments, mmu-let-7a may contribute to cerebrovascular mCEC alterations following inhaled dust exposure.

AB0387 TREATMENT STATUS FOR OSTEOPOROSIS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: CROSS-SECTIONAL ANALYSIS FROM A LUPUS REGISTRY OF NATIONWIDE INSTITUTIONS (LUNA)

Background:

Osteoporosis is one of the most important adverse effects of glucocorticoids in patients with systemic lupus erythematosus (SLE). Because osteoporosis is accelerated by chronic kidney disease (CKD), more attention should be paid to the treatment for osteoporosis in SLE patients with CKD. Many treatment options for osteoporosis have emerged recently, but treatment status in patients with SLE is not elucidated.

Objectives:

The purpose of this study is to elucidate the treatment status for osteoporosis in patients with SLE among the CKD stages.

Methods:

Using data from lupus registry of nationwide institutions (LUNA), a cross-sectional analysis was performed. We firstly described treatment status for osteoporosis in all enrolled patients. Secondary, treatment status for osteoporosis was compared among CKD stages. Finally, bone damage in Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) was compared among CKD stages.

Results:

The median age (interquartile range [IQR]) of enrolled 917 patients was 44 (34- 57) years and 809 patients (88%) were female. CKD stages were follows: CKD stage 1, 234 (26%); CKD stage 2, 465 (51%); CKD stage 3, 189 (21%); CKD stage 4, 9 (1%); CKD stage 5, 16 (2%). Median (IQR) age, female sex, and median (IQR) previous maximum dose of prednisolone in patients with and without CKD (≥CKD stage 3) were 56 (46.5-66) and 41 (32-50), 191 (89%) and 615 (88%), and 40 (30-60) and 40 (30-55) mg/day, respectively. Bisphosphonate was administered in 388 (42%) patients, vitamin D supplements in 448 (49%), Ca supplements in 36 (4%), denosumab in 20 (2%) and teriparatide in 14 (2%), respectively. Of enrolled patients, any treatment for osteoporosis was not administered in 226 (25%) patients. In spite of more frequent bone damage in patients with CKD compared to those without CKD (15% vs 10%, p=0.036), treatment status did not differ between patients with and without CKD (bisphosphonate: 41% vs 46%, p=0.29; vitamin D supplements: 50% vs 44%, p=0.14).

Conclusion:

About a quarter of patients with SLE did not take any treatment for osteoporosis. Treatment for osteoporosis might be strengthened to prevent bone damage in SLE patients with CKD.

Disclosure of Interests:

KEN-EI SADA Speakers bureau: I received speaker’s fee from GSK and Astra Zeneca K.K., Keigo Hayashi: None declared, Yosuke ASANO: None declared, Yu Katayama: None declared, Sumie Hiramatsu Asano: None declared, Keiji Ohashi: None declared, Michiko Morishita: None declared, Haruki Watanabe: None declared, Mariko Narazaki: None declared, Yoshinori Matsumoto: None declared, Nobuyuki Yajima: None declared, Ryusuke Yoshimi: None declared, Yasuhiro Shimojima: None declared, Shigeru Ono: None declared, Hiroshi Kajiyama: None declared, Kunihiro Ichinose: None declared, Shuzo Sato: None declared, Michio Fujiwara: None declared, Jun Wada: None declared

Damage accrual related to pregnancies before and after diagnosis of systemic lupus erythematosus: a cross-sectional and nested case-control analysis from a lupus registry

OBJECTIVE

The objective of this study was to evaluate the chronic damage associated with pregnancies before and after the diagnosis of systemic lupus erythematosus (SLE).

METHODS

Using childbearing-aged female SLE patient data registered at the Okayama and Showa University Hospitals, a nested case-control analysis was performed to investigate the relationship between pregnancy and chronic damage using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI).

RESULTS

Pregnancy occurred in 22 patients before and 13 patients after the diagnosis of SLE in 104 eligible patients. Live births occurred in 82% (33/40) and 50% (9/18) of the pregnancies before and after the diagnosis of SLE, respectively. After matching age and disease duration, 33 case patients with chronic damage (SDI ≥ 1) and 33 control patients without chronic damage (SDI = 0) were selected. Hypertension was more frequent in cases than in controls (48% vs. 24%, p = 0.041). Pregnancies before and after the diagnosis of SLE were comparable between cases and controls (before the diagnosis: nine case patients and eight control patients; after the diagnosis: three case patients and five control patients; p = 1.00). Even after adjusting for hypertension using multivariate analysis, the pregnancies before and after the diagnosis were not significant predictors for chronic damage (odds ratio = 1.48 (95% confidence interval 0.33-6.65)), p = 0.60 of the pregnancy before the diagnosis; odds ratio = 0.78 (95% confidence interval 0.13-4.74), p = 0.78 of the pregnancy after the diagnosis).

CONCLUSION

Pregnancies, either before or after the diagnosis of SLE, did not show any differences in chronic damage. Our results help alleviate fears regarding childbearing in female patients with SLE and their families.

Acute Blood Pressure and Cardiovascular Effects of Near-Roadway Exposures With and Without N95 Respirators

BACKGROUND

The risk for cardiovascular events increases within hours of near-roadway exposures. We aimed to determine the traffic-related air pollution (TRAP) and biological mechanisms involved and if reducing particulate matter <2.5 µm (PM2.5) inhalation is protective.

METHODS

Fifty healthy-adults underwent multiple 2-hour near-roadway exposures (Tuesdays to Fridays) in Ann Arbor during 2 separate weeks (randomized to wear an N95 respirator during 1 week). Monday both weeks, participants rested 2 hours in an exam room (once wearing an N95 respirator). Brachial blood pressure, aortic hemodynamics, and heart rate variability were repeatedly measured during exposures. Endothelial function (reactive hyperemia index [RHI]) was measured post-exposures (Thursdays). Black carbon (BC), total particle count (PC), PM2.5, noise and temperature were measured throughout exposures.

RESULTS

PM2.5 (9.3 ± 7.7 µg/m3), BC (1.3 ± 0.6 µg/m3), PC (8,375 ± 4,930 particles/cm3) and noise (69.2 ± 4.2 dB) were higher (P values <0.01) and aortic hemodynamic parameters trended worse while near-roadway (P values<0.15 vs. exam room). Other outcomes were unchanged. Aortic hemodynamics trended towards improvements with N95 respirator usage while near-roadway (P values<0.15 vs. no-use), whereas other outcomes remained unaffected. Higher near-roadway PC and BC exposures were associated with increases in aortic augmentation pressures (P values<0.05) and trends toward lower RHI (P values <0.2). N95 respirator usage did not mitigate these adverse responses (nonsignificant pollutant-respirator interactions). Near-roadway outdoor-temperature and noise were also associated with cardiovascular changes.

CONCLUSIONS

Exposure to real-world combustion-derived particulates in TRAP, even at relatively low concentrations, acutely worsened aortic hemodynamics. Our mixed findings regarding the health benefits of wearing N95 respirators support that further studies are needed to validate if they adequately protect against TRAP given their growing worldwide usage.

Reduction of personal PM2.5 exposure via indoor air filtration systems in Detroit: an intervention study

The adverse health effects of fine particulate matter (PM < 2.5 μm in diameter [PM_2.5]) air pollution are well-documented. There is a growing body of evidence that high-efficiency particulate arrestance (HEPA) filtration can reduce indoor PM_2.5 concentrations and deliver some health benefits via the reduction of exposure to PM. However, few studies have tested the ability of portable air filtration systems to lower overall personal-level PM_2.5 exposures. The Reducing Air Pollution in Detroit Intervention Study (RAPIDS) was designed to evaluate cardiovascular health benefits and personal PM_2.5 exposure reductions via indoor portable air filtration systems among senior citizens in Detroit, Michigan. We evaluated the utility of two commercially available high-efficiency (HE: true-HEPA) and low-efficiency (LE: HEPA-type) indoor air filtration to reduce indoor PM_2.5 concentrations and personal PM_2.5 exposures for 40 participants in a double-blinded randomized crossover intervention. Each participant was subjected to three intervention scenarios: HE, LE, or no filter (control) of three consecutive days each, during which personal, indoor, and outdoor PM_2.5 concentrations were measured daily. For mean indoor PM_2.5 concentrations, we observed 60 and 52% reductions using HE and LE filters, respectively, relative to no filtration. Personal PM_2.5 exposures were reduced by 53 and 31% using HE and LE filters, respectively, when compared with the control scenario. To our knowledge, this is the first indoor air filtration intervention study to examine the effectiveness of both HE and LE filters in reducing personal PM_2.5 exposures.

Neighborhood air pollution and household environmental health as it relates to respiratory health and healthcare utilization among elderly persons with asthma

Objective: The study investigated the associations between fine particulate matter (PM_2.5; <2.5 μm in diameter), indoor environment, pulmonary function, and healthcare utilization in a vulnerable group of elderly persons with asthma. We hypothesized that environmental conditions were associated with adverse pulmonary health outcomes. Methods: The study involved elderly (n = 76; mean age 64.6 years; 48 women) vulnerable persons in Detroit, Michigan, USA, with physician-diagnosed asthma. Exposure variables included measured outdoor PM_2.5, self-rated outdoor and household environmental pollutants. Outcome variables were self-rated and measured pulmonary function, and asthma-related healthcare utilization. Results: Mean ambient PM_2.5 concentrations during the study was 14.14 ± (S.D. 6.36) µg/m³ during the summer and 14.20 (6.33) during the winter (p = 0.95). In multiple regression analyses, adjusting for age and gender, mean 6-month concentration of PM_2.5 was related to shortness of breath (SHOB; standardized β = 0.26, p = 0.02) and inversely with self-rated respiratory health (SRRH; β = 0.28, p = 0.02). However, PM_2.5 did not predict lung function (FEV₁% predicted and FEV₁/FVC). However, PM_2.5 was related to use of asthma controller drugs (β = 0.38, p = 0.001). Participants' air pollution ratings predicted total healthcare utilization (β = 0.33, p = 0.01). Conclusions: In elderly persons with asthma, living near heavy industry and busy highways, objective and perceived environmental pollution relate to participants' respiratory health and healthcare utilization. Importantly, air pollution might increase use of asthma controller drugs containing corticosteroids with implication for elderly persons' risk to develop osteoporosis and cardiovascular disease.

Progressive reduction of serum complement levels: a risk factor for relapse in patients with hypocomplementemia in systemic lupus erythematosus

Objective

Serologically active clinically quiescent (SACQ)-SLE is a subtype of systemic lupus erythematosus (SLE); most SACQ-SLE patients relapse. Although complement and/or anti-dsDNA level fluctuations during SACQ status are reportedly not useful for predicting relapse, they might be useful in specific clinical settings. We aimed to assess the correlation between future relapse and progressive reductions in serum complement levels following remission in patients with hypocomplementemia .

Methods

We retrospectively reviewed patients aged ≥15 years who were treated with ≥20 mg/day of prednisolone for remission induction. After achieving remission, the patients treated with prednisolone tapered to ≤15 mg/day without relapse and followed by hypocomplementemia (first hypocomplementemia point) were analyzed. The primary outcome was the relapse during the first 24 months.

Results

Seventy-six patients were enrolled; 31 (40.8%) relapsed. A ≥10% reduction after the first hypocomplementemia point in serum C3, C4, and CH50 levels was found in 10, 21, and 16 patients, respectively. Hazard ratios (95% confidence intervals) for relapse were 2.32 (0.92–5.12) for serum C3 levels and 2.46 (1.18–5.01) for serum C4 levels. Progressive reductions in serum C3 and C4 levels had relatively high specificity (93.3% and 82.2%) but limited sensitivity (22.6% and 41.9%) for predicting relapse. However, simultaneous progressive reduction in C3 levels and increase in anti-dsDNA antibody levels had the highest specificity (97.8%), and simultaneous progressive reduction in C4 levels or increase in anti-dsDNA antibody levels had the highest sensitivity (71.0%).

Conclusion

Simultaneous progressive reductions in complement levels and increases in anti-dsDNA antibody levels may indicate future relapse SACQ-SLE patients.

Effect of Portable Air Filtration Systems on Personal Exposure to Fine Particulate Matter and Blood Pressure Among Residents in a Low-Income Senior Facility: A Randomized Clinical Trial

IMPORTANCE

Fine particulate matter (smaller than 2.5 μm) (PM2.5) air pollution is a major global risk factor for cardiovascular (CV) morbidity and mortality. Few studies have tested the benefits of portable air filtration systems in urban settings in the United States.

OBJECTIVE

To investigate the effectiveness of air filtration at reducing personal exposures to PM2.5 and mitigating related CV health effects among older adults in a typical US urban location.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, double-blind crossover intervention study was conducted from October 21, 2014, through November 4, 2016, in a low-income senior residential building in Detroit, Michigan. Forty nonsmoking older adults were enrolled, with daily CV health outcome and PM2.5 exposure measurements.

INTERVENTIONS

Participants were exposed to the following three 3-day scenarios separated by 1-week washout periods: unfiltered air (sham filtration), low-efficiency (LE) high-efficiency particulate arrestance (HEPA)-type filtered air, and high-efficiency (HE) true-HEPA filtered air using filtration systems in their bedroom and living room.

MAIN OUTCOMES AND MEASURES

The primary outcome was brachial blood pressure (BP). Secondary outcomes included aortic hemodynamics, pulse-wave velocity, and heart rate variability. Exposures to PM2.5 were measured in the participants' residences and by personal monitoring.

RESULTS

The 40 participants had a mean (SD) age of 67 (8) years (62% men). Personal PM2.5 exposures were significantly reduced by air filtration from a mean (SD) of 15.5 (10.9) μg/m3 with sham filtration to 10.9 (7.4) μg/m3 with LE fitration and 7.4 (3.3) μg/m3 with HE filtration. Compared with sham filtration, any filtration for 3 days decreased brachial systolic and diastolic BP by 3.2 mm Hg (95% CI, -6.1 to -0.2 mm Hg) and 1.5 mm Hg (95% CI, -3.3 to 0.2 mm Hg), respectively. A continuous decrease occurred in systolic and diastolic BP during the 3-day period of LE filtration, with a mean of 3.4 mm Hg (95% CI, -6.8 to -0.1 mm Hg) and 2.2 mm Hg (95% CI, -4.2 to -0.3 mm Hg), respectively. For HE filtration, systolic and diastolic BP decreased by 2.9 mm Hg (95% CI, -6.2 to 0.5 mm Hg) and 0.8 mm Hg (95% CI, -2.8 to 1.2 mm Hg), respectively. Most secondary outcomes were not significantly improved.

CONCLUSIONS AND RELEVANCE

Results of this study showed that short-term use of portable air filtration systems reduced personal PM2.5 exposures and systolic BP among older adults living in a typical US urban location. The use of these relatively inexpensive systems is potentially cardioprotective against PM2.5 exposures and warrants further research.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03334565.

Short-Term Blood Pressure Responses to Ambient Fine Particulate Matter Exposures at the Extremes of Global Air Pollution Concentrations

BACKGROUND

Fine particulate matter (PM2.5) air pollution is a leading cause of global cardiovascular mortality. A key mechanism may be PM2.5-induced blood pressure (BP) elevations. Whether consistent prohypertensive responses persist across the breadth of worldwide pollution concentrations has never been investigated.

METHODS

We evaluated the hemodynamic impact of short-term exposures to ambient PM2.5 in harmonized studies of healthy normotensive adults (4 BP measurements per participant) living in both a highly polluted (Beijing) and clean (Michigan) location.

RESULTS

Prior 7-day outdoor-ambient and 24-hour personal-level PM2.5 concentration averages were much higher in Beijing (86.7 ± 52.1 and 52.4 ± 79.2 µg/m3) compared to Michigan (9.1 ± 1.8 and 12.2 ± 17.0 µg/m3). In Beijing (n = 73), increased outdoor-ambient exposures (per 10 µg/m3) during the prior 1-7 days were associated with significant elevations in diastolic BP (0.15-0.17 mm Hg). In overweight adults (body mass index ≥25 kg/m2), significant increases in both systolic (0.34-0.44 mm Hg) and diastolic (0.22-0.66 mm Hg) BP levels were observed. Prior 24-hour personal-level exposures also significantly increased BP (0.41/0.61 mm Hg) in overweight participants. Conversely, low PM2.5 concentrations in Michigan (n = 50), on average within Air Quality Guidelines, were not associated with BP elevations.

CONCLUSIONS

Our findings demonstrate that short-term exposures to ambient PM2.5 in a highly polluted environment can promote elevations in BP even among healthy adults. The fact that no adverse hemodynamic responses were observed in a clean location supports the key public health importance of international efforts to improve air quality as part of the global battle against hypertension.

Refractory neuromyelitis optica spectrum disorder in systemic lupus erythematosus successfully treated with rituximab

We present a case of a woman with systemic lupus erythematosus (SLE) who had refractory episodes of neuromyelitis optica spectrum disorder (NMOSD) and was successfully treated with rituximab. She was positive for anti-aquaporin-4 (AQP4) antibody and had typical cranial and longitudinally extended spinal lesions but no optic nerve involvement. There is no established treatment for NMOSD/SLE overlap cases. Our experience suggests that rituximab may be effective for patients with combined SLE and anti-AQP4 antibody-positive NMOSD.

Refractory neuromyelitis optica spectrum disorder in systemic lupus erythematosus successfully treated with rituximab

We present a case of a woman with systemic lupus erythematosus (SLE) who had refractory episodes of neuromyelitis optica spectrum disorder (NMOSD) and was successfully treated with rituximab. She was positive for anti-aquaporin-4 (AQP4) antibody and had typical cranial and longitudinally extended spinal lesions but no optic nerve involvement. There is no established treatment for NMOSD/SLE overlap cases. Our experience suggests that rituximab may be effective for patients with combined SLE and anti-AQP4 antibody-positive NMOSD.

Personal-level exposure to environmental temperature is a superior predictor of endothelial-dependent vasodilatation than outdoor-ambient level

Environmental temperatures influence cardiovascular physiology. However, the majority of time is spent indoors, making outdoor-ambient temperatures inaccurate estimates of true exposures encountered by most individuals. We evaluated in 50 healthy adults the associations between previous 7-day outdoor-ambient (four occasions) and prior 24-hour personal-level (two occasions) environmental temperature exposures with blood pressure, heart rate variability, sleep parameters, and endothelial-dependent vasodilatation (brachial flow-mediated dilatation [FMD]) using generalized estimating equations. Participants (34 females; age, 32.1 ± 9.6 years) had normal blood pressures (107.8 ± 13.3/70.2 ± 9.4 mm Hg), FMD (7.4 ± 2.8%), as well as sleep and heart rate variability parameters. Mean 7-day outdoor-ambient (4.6 ± 9.7°C) differed from personal-level temperature exposures (22.0 ± 3.0°C). Colder outdoor-ambient temperatures (per -10°C) over the previous 1-6 days (rolling averages) were associated with decreases in FMD: -0.57% (95% confidence interval [CI]: -1.14% to 0.01%, P = .055) to -0.62% (95% CI: -1.07% to -0.18%, P = .006). However, a 10°C decrease in personal-level temperature during the prior 24 hours was associated with a greater decrement in FMD: -2.44% (95% CI: -4.74% to -0.13%, P = .038). Both were also linearly related to FMD during all seasons and without a threshold temperature. Other end points were not significantly related to either temperature level in this study. Short-term exposures to colder environmental temperatures reduced endothelial-dependent vasodilatation, supporting the epidemiologic associations with heightened cardiovascular risk. We show here for the first time that temperature exposures characterized at the personal level may be more robust predictors of endothelial function than outdoor-ambient levels.

Characterization of Urban Atmospheres during Inhalation Exposure Studies in Detroit and Grand Rapids, Michigan

An inhalation exposure study for particulate matter (PM) investigates links between exposure and observed changes in respiratory function by evaluating the interactions of chemical and physical properties of the PM with physiological mechanisms. Laboratory studies are useful in this regard, but provide limited information because of the difficulty in reproducing real atmospheric PM compositions and processes. To better understand the types of particles to which people are actually exposed in their daily lives, and the human health risks for source-specific PM, a real world assessment of the source-to-receptor pathways for ambient PM is vital. This was accomplished using a unique mobile air research laboratory (AirCARE1) which enables inhalation exposure studies in real-world settings. The overall goal of this study was to determine the effects of concentrated air particulates (CAPs) from 2 different urban atmospheres in Michigan on the lungs of ovalbumin-sensitized rats concurrently challenged with the allergen. Our work demonstrated that short-term (8 hours) exposure to ambient fine particulate matter (aerodynamic diameter ≤ 2.5 μm; PM2.5) concentrated from 2 different urban atmospheres in Michigan induced distinct allergic responses in the lungs of rats. This paper presents detailed characterization of CAPs and their sources in an effort to define possible associations between the observed health effects and source-specific ambient PM2.5.

Repeated dose (28-day) administration of silver nanoparticles of varied size and coating does not significantly alter the indigenous murine gut microbiome

Silver nanoparticles (AgNPs) have been used as antimicrobials in a number of applications, including topical wound dressings and coatings for consumer products and biomedical devices. Ingestion is a relevant route of exposure for AgNPs, whether occurring unintentionally via Ag dissolution from consumer products, or intentionally from dietary supplements. AgNP have also been proposed as substitutes for antibiotics in animal feeds. While oral antibiotics are known to have significant effects on gut bacteria, the antimicrobial effects of ingested AgNPs on the indigenous microbiome or on gut pathogens are unknown. In addition, AgNP size and coating have been postulated as significantly influential towards their biochemical properties and the influence of these properties on antimicrobial efficacy is unknown. We evaluated murine gut microbial communities using culture-independent sequencing of 16S rRNA gene fragments following 28 days of repeated oral dosing of well-characterized AgNPs of two different sizes (20 and 110 nm) and coatings (PVP and Citrate). Irrespective of size or coating, oral administration of AgNPs at 10 mg/kg body weight/day did not alter the membership, structure or diversity of the murine gut microbiome. Thus, in contrast to effects of broad-spectrum antibiotics, repeat dosing of AgNP, at doses equivalent to 2000 times the oral reference dose and 100-400 times the effective in vitro anti-microbial concentration, does not affect the indigenous murine gut microbiome.

Oil sands development and its impact on atmospheric wet deposition of air pollutants to the Athabasca Oil Sands Region, Alberta, Canada

Characterization of air pollutant deposition resulting from Athabasca oil sands development is necessary to assess risk to humans and the environment. To investigate this we collected event-based wet deposition during a pilot study in 2010-2012 at the AMS 6 site 30 km from the nearest upgrading facility in Fort McMurray, AB, Canada. Sulfate, nitrate and ammonium deposition was (kg/ha) 1.96, 1.60 and 1.03, respectively. Trace element pollutant deposition ranged from 2 × 10(-5) - 0.79 and exhibited the trend Hg < Se < As < Cd < Pb < Cu < Zn < S. Crustal element deposition ranged from 1.4 × 10(-4) - 0.46 and had the trend: La < Ce < Sr < Mn < Al < Fe < Mg. S, Se and Hg demonstrated highest median enrichment factors (130-2020) suggesting emissions from oil sands development, urban activities and forest fires were deposited. High deposition of the elements Sr, Mn, Fe and Mg which are tracers for soil and crustal dust implies land-clearing, mining and hauling emissions greatly impacted surrounding human settlements and ecosystems.

Effects of particle size and coating on toxicologic parameters, fecal elimination kinetics and tissue distribution of acutely ingested silver nanoparticles in a mouse model

Consumer exposure to silver nanoparticles (AgNP) via ingestion can occur due to incorporation of AgNP into products such as food containers and dietary supplements. AgNP variations in size and coating may affect toxicity, elimination kinetics or tissue distribution. Here, we directly compared acute administration of AgNP of two differing coatings and sizes to mice, using doses of 0.1, 1 and 10 mg/kg body weight/day administered by oral gavage for 3 days. The maximal dose is equivalent to 2000× the EPA oral reference dose. Silver acetate at the same doses was used as ionic silver control. We found no toxicity and no significant tissue accumulation. Additionally, no toxicity was seen when AgNP were dosed concurrently with a broad-spectrum antibiotic. Between 70.5% and 98.6% of the administered silver dose was recovered in feces and particle size and coating differences did not significantly influence fecal silver. Peak fecal silver was detected between 6- and 9-h post-administration and <0.5% of the administered dose was cumulatively detected in liver, spleen, intestines or urine at 48 h. Although particle size and coating did not affect tissue accumulation, silver was detected in liver, spleen and kidney of mice administered ionic silver at marginally higher levels than those administered AgNP, suggesting that silver ion may be more bioavailable. Our results suggest that, irrespective of particle size and coating, acute oral exposure to AgNP at doses relevant to potential human exposure is associated with predominantly fecal elimination and is not associated with accumulation in tissue or toxicity.

Exposure to concentrated ambient particulate matter induces reversible increase of heart weight in spontaneously hypertensive rats

BACKGROUND

Exposure to ambient PM2.5 increases cardiovascular mortality and morbidity. To delineate the underlying biological mechanism, we investigated the time dependence of cardiovascular response to chronic exposure to concentrated ambient PM2.5 (CAP).

METHODS

Spontaneously hypertensive rats (SHR) were exposed to CAP for 15 weeks, and blood pressure (BP), cardiac function and structure, and inflammations of lung, hypothalamus, and heart were measured at different time points.

RESULTS

Chronic exposure to CAP significantly increased BP, and withdrawal from CAP exposure restored BP. Consistent with its BP effect, chronic exposure to CAP significantly decreased cardiac stroke volume and output in SHR, accompanied by increased heart weight and increased cardiac expression of hypertrophic markers ACTA1 and MYH7. Withdrawal from CAP exposure restored cardiac function, weight, and expression of hypertrophic markers, supporting the notion that cardiac dysfunction and hypertrophy is subsequent to hypertension. In agreement with the role of systemic inflammation in mediating the cardiovascular effects of CAP exposure, chronic exposure to CAP markedly increased expression of pro-inflammatory cytokines in lung, heart, and hypothalamus. However, withdrawal from exposure resolves inflammation in the heart and hypothalamus, but not in the lung, suggesting that CAP exposure-induced systemic inflammation may be independent of pulmonary inflammation.

CONCLUSION

Chronic exposure to CAP induces reversible cardiac dysfunction and hypertrophy, which is likely to be subsequent to the elevation in BP and induction of systemic inflammation as evidenced by increased mRNA expression of pro-inflammatory cytokines in diverse tissues.

Higher fine particulate matter and temperature levels impair exercise capacity in cardiac patients

OBJECTIVE

Fine particulate matter (PM2.5) air pollution and variations in ambient temperature have been linked to increased cardiovascular morbidity and mortality. However, no large-scale study has assessed their effects on directly measured aerobic functional capacity among high-risk patients.

METHODS

Using a cross-sectional observational design, we evaluated the effects of ambient PM2.5 and temperature levels over 7 days on cardiopulmonary exercise test results performed among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from January 2003 to August 2011) using multiple linear regression analyses (controlling for age, sex, body mass index).

RESULTS

Peak exercise oxygen consumption was significantly decreased by approximately 14.9% per 10 μg/m(3) increase in ambient PM2.5 levels (median 10.7 μg/m(3), IQR 10.1 μg/m(3)) (lag days 6-7). Elevations in PM2.5 were also related to decreases in ventilatory threshold (lag days 5-7) and peak heart rate (lag days 2-3) and increases in peak systolic blood pressure (lag days 4-5). A 10°C increase in temperature (median 10.5°C, IQR 17.5°C) was associated with reductions in peak exercise oxygen consumption (20.6-27.3%) and ventilatory threshold (22.9-29.2%) during all 7 lag days. In models including both factors, the outcome associations with PM2.5 were attenuated whereas the effects of temperature remained significant.

CONCLUSIONS

Short-term elevations in ambient PM2.5, even at low concentrations within current air quality standards, and/or higher temperatures were associated with detrimental changes in aerobic exercise capacity, which can be linked to a worse quality of life and cardiovascular prognosis among cardiac rehabilitation patients.

Understanding Air Pollution and Cardiovascular Diseases: Is It Preventable?

Fine particulate matter (<2.5 µm, PM_2.5) air pollution is a leading risk factor for morbidity and mortality worldwide. The largest portion of adverse health effects is from cardiovascular diseases. In North America, PM_2.5 concentrations have shown a steady decline over the past several decades; however, the opposite trend has occurred throughout much of the developing world whereby daily concentrations commonly reach extraordinarily high levels. While air quality regulations can reduce air pollution at a societal level, what individuals can do to reduce their personal exposures remains an active field of investigation. Here, we review the emerging evidence that several interventions (e.g., air filters) and/or behavioral changes can lower PM pollution exposure and as such, may be capable of mitigating the ensuing adverse cardiovascular health consequences. Air pollution remains a worldwide epidemic and a multi-tiered prevention strategy is required in order to optimally protect global public health.

Exploration of the composition and sources of urban fine particulate matter associated with same-day cardiovascular health effects in Dearborn, Michigan

The objective was to explore associations of chemical components and source factors of ambient fine particulate matter (aerodynamic diameter ≤ 2.5 μm; PM2.5) with cardiovascular (CV) changes following same-day exposure to ambient PM2.5. Twenty-five healthy adults living in rural Michigan were exposed to ambient air in an urban/industrial community for 4 to 5 h daily for five consecutive days. CV health outcomes were measured 1-2 h post exposure. Contributing emission sources were identified via positive matrix factorization. We examined associations between PM2.5 mass, composition and source factors, and same-day changes in CV outcomes using mixed-model analyses. PM2.5 mass (10.8 ± 6.8 μg/m(3)), even at low ambient levels, was significantly associated with increased heart rate (HR). Trace elements as well as secondary aerosol, diesel/urban dust and iron/steel manufacturing factors potentially explained the HR changes. However, trace element analysis demonstrated additional associations with other CV responses including changes in blood pressure (BP), arterial compliance, autonomic balance and trends toward reductions in endothelial function. Two factors were related to BP changes (diesel/urban dust, motor vehicle) and trends toward impaired endothelial function (diesel/urban dust). This study indicates composition of PM2.5 and its sources may contribute to CV health effects independently of PM2.5 mass.

The characteristics of coarse particulate matter air pollution associated with alterations in blood pressure and heart rate during controlled exposures

Although fine particulate matter (PM) air pollution <2.5 μm in aerodynamic diameter (PM2.5) is a leading cause of global morbidity and mortality, the potential health effects of coarse PM (2.5-10 μm in aerodynamic diameter; PM10-2.5) remain less clearly understood. We aimed to elucidate the components within coarse PM most likely responsible for mediating these hemodynamic alterations. Thirty-two healthy adults (25.9 ± 6.6 years) were exposed to concentrated ambient coarse PM (CAP) (76.2 ± 51.5 μg/m(3)) and filtered air (FA) for 2 h in a rural location in a randomized double-blind crossover study. The particle constituents (24 individual elements, organic and elemental carbon) were analyzed from filter samples and associated with the blood pressure (BP) and heart rate (HR) changes occurring throughout CAP and FA exposures in mixed model analyses. Total coarse PM mass along with most of the measured elements were positively associated with similar degrees of elevations in both systolic BP and HR. Conversely, total PM mass was unrelated, whereas only two elements (Cu and Mo) were positively associated with and Zn was inversely related to diastolic BP changes during exposures. Inhalation of coarse PM from a rural location rapidly elevates systolic BP and HR in a concentration-responsive manner, whereas the particulate composition does not appear to be an important determinant of these responses. Conversely, exposure to certain PM elements may be necessary to trigger a concomitant increase in diastolic BP. These findings suggest that particulate mass may be an adequate metric of exposure to predict some, but not all, hemodynamic alterations induced by coarse PM mass.

No effect of acute exposure to coarse particulate matter air pollution in a rural location on high-density lipoprotein function

CONTEXT

High-density lipoprotein (HDL) particles perform numerous vascular-protective functions. Animal studies demonstrate that exposure to fine or ultrafine particulate matter (PM) can promote HDL dysfunction. However, the impact of PM on humans remains unknown.

OBJECTIVE

We aimed to determine the effect of exposure to coarse concentrated ambient particles (CAP) on several metrics of HDL function in healthy humans.

METHODS

Thirty-two adults (25.9 ± 6.6 years) were exposed to coarse CAP [76.2 ± 51.5 µg·m(-3)] in a rural location and filtered air (FA) for 2 h in a randomized double-blind crossover study. Venous blood collected 2- and 20-h post-exposures was measured for HDL-mediated efflux of [(3)H]-cholesterol from cells and 20-h exposures for HDL anti-oxidant capacity by a fluorescent assay and paraoxonase activity. The changes [median (first, third quartiles)] between exposures among 29 subjects with available results were compared by matched Wilcoxon tests.

RESULTS

HDL-mediated cholesterol efflux capacity did not differ between exposures at either time point [16.60% (15.17, 19.19) 2-h post-CAP versus 17.56% (13.43, 20.98) post-FA, p  =  0.768 and 14.90% (12.47, 19.15) 20-h post-CAP versus 17.75% (13.22, 23.95) post-FA, p  =  0.216]. HOI [0.26 (0.24, 0.35) versus 0.28 (0.25, 0.40), p = 0.198] and paraoxonase activity [0.54 (0.39, 0.82) versus 0.60 μmol·min(-1 )ml plasma(-1) (0.40, 0.85), p = 0.137] did not differ 20-h post-CAP versus FA, respectively.

CONCLUSIONS

Brief inhalation of coarse PM from a rural location did not acutely impair several facets of HDL functionality. Whether coarse PM derived from urban sites, fine particles or longer term PM exposures can promote HDL dysfunction warrant future investigations.

Hemodynamic, autonomic, and vascular effects of exposure to coarse particulate matter air pollution from a rural location

BACKGROUND

Fine particulate matter (PM) air pollution is associated with numerous adverse health effects, including increased blood pressure (BP) and vascular dysfunction. Coarse PM substantially contributes to global air pollution, yet differs in characteristics from fine particles and is currently not regulated. However, the cardiovascular (CV) impacts of coarse PM exposure remain largely unknown.

OBJECTIVES

Our goal was to elucidate whether coarse PM, like fine PM, is itself capable of eliciting adverse CV responses.

METHODS

We performed a randomized double-blind crossover study in which 32 healthy adults (25.9 ± 6.6 years of age) were exposed to concentrated ambient coarse particles (CAP; 76.2 ± 51.5 μg/m(3)) in a rural location and filtered air (FA) for 2 hr. We measured CV outcomes during, immediately after, and 2 hr postexposures.

RESULTS

Both systolic (mean difference = 0.32 mmHg; 95% CI: 0.05, 0.58; p = 0.021) and diastolic BP (0.27 mmHg; 95% CI: 0.003, 0.53; p = 0.05) linearly increased per 10 min of exposure during the inhalation of coarse CAP when compared with changes during FA exposure. Heart rate was on average higher (4.1 bpm; 95% CI: 3.06, 5.12; p < 0.0001) and the ratio of low-to-high frequency heart rate variability increased (0.24; 95% CI: 0.07, 0.41; p = 0.007) during coarse particle versus FA exposure. Other outcomes (brachial flow-mediated dilatation, microvascular reactive hyperemia index, aortic hemodynamics, pulse wave velocity) were not differentially altered by the exposures.

CONCLUSIONS

Inhalation of coarse PM from a rural location is associated with a rapid elevation in BP and heart rate during exposure, likely due to the triggering of autonomic imbalance. These findings add mechanistic evidence supporting the biological plausibility that coarse particles could contribute to the triggering of acute CV events.

Exaggerated effects of particulate matter air pollution in genetic type II diabetes mellitus

Background

Prior experimental and epidemiologic data support a link between exposure to fine ambient particulate matter (<2.5 μm in aerodynamic diameter, PM_2.5) and development of insulin resistance/Type II diabetes mellitus. This study was designed to investigate whether inhalational exposure of concentrated PM_2.5 in a genetically susceptible animal model would result in abnormalities in energy metabolism and exacerbation of peripheral glycemic control.

Methods

KKay mice, which are susceptible to Type II DM, were assigned to either concentrated ambient PM_2.5 or filtered air (FA) for 5–8 weeks via a whole body exposure system. Glucose tolerance, insulin sensitivity, oxygen consumption and heat production were evaluated. At euthanasia, blood, spleen and visceral adipose tissue were collected to measure inflammatory cells using flow cytometry. Standard immnunohistochemical methods, western blotting and quantitative PCR were used to assess targets of interest.

Results

PM_2.5 exposure influenced energy metabolism including O₂ consumption, CO₂ production, respiratory exchange ratio and thermogenesis. These changes were accompanied by worsened insulin resistance, visceral adiposity and inflammation in spleen and visceral adipose depots. Plasma adiponectin were decreased in response to PM_2.5 exposure while leptin levels increased. PM_2.5 exposure resulted in a significant increase in expression of inflammatory genes and decreased UCP1 expression in brown adipose tissue and activated p38 and ERK pathways in the liver of the KKay mice.

Conclusions

Concentrated ambient PM_2.5 exposure impairs energy metabolism, concomitant with abnormalities in glucose homeostasis, increased inflammation in insulin responsive organs, brown adipose inflammation and results in imbalance in circulating leptin/adiponectin levels in a genetically susceptible diabetic model. These results provide additional insights into the mechanisms surrounding air pollution mediated susceptibility to Type II DM.

PM2.5-induced cardiovascular dysregulation in rats is associated with elemental carbon and temperature-resolved carbon subfractions

Background

We tested the hypothesis that cardiovascular responses to PM_2.5 exposure will be enhanced in hypertensive rats and linked to specific carbonaceous pollutants in an urban industrial setting.

Methods

Spontaneously hypertensive rats were exposed by inhalation to concentrated PM_2.5 in an industrial area of Dearborn, Michigan, for four consecutive summer days. Blood pressure (BP), heart rate (HR) and HR variability (HRV) metrics (SDNN, RMSSD) were assessed by radiotelemetry and compared to 1 h- and 8 h-averaged fluctuations in PM_2.5 composition, with a focus on elemental and organic carbon (EC and OC, respectively), and temperature-resolved subfractions (EC1-EC5, PC (pyrolized carbon), and OC1-OC4), as well as other major and minor PM components.

Results

Mean HR and BP were increased, while HRV was decreased over 4 days of exposure. Using 1 h averages, EC (1 μg/m³ increase) was associated with increased HR of 11-32 bpm (4-11% increase), 1.2-1.5 ms (22-27%) decreases in SDNN, 3-14 mmHg (1.5-8%) increases in systolic BP, and 5-12 mmHg (4-9%) increases in diastolic BP. By comparison, associations with OC were negligible. Using 8 h averages, EC subfractions were linked with increased heart rate (EC1: 13 bpm; EC2, EC3, PC: <5 bpm) and SDNN (EC1> > EC2 > EC3, EC4, PC), but with decreased RMSSD (EC2, EC5 > EC3, EC4). Minimal effects were associated with OC and OC1. Associations between carbon subfractions and BP were negligible. Associations with non-carbonaceous components and trace elements were generally non-significant or of negligible effect size.

Conclusions

These findings are the first to describe associations between acute cardiovascular responses and thermally resolved carbon subfractions. We report that cardiovascular responses to PM_2.5 carbonaceous materials appear to be driven by EC and its EC1 fraction.

Abstract 405: Central IKKß Inhibition Prevents Air Pollution--Mediated Peripheral Inflammation and Exaggeration of Type 2 Diabetes

Objective: Prior experimental and epidemiologic data support a link between exposure to fine ambient particulate matter (<2.5 μm in aerodynamic diameter, PM 2.5 ) and development of insulin resistance/Type II diabetes mellitus (Type II DM). We investigated the role of hypothalamic inflammation in PM 2.5 -mediated diabetes development and the underlying mechanism.

Approach and results: KKay mice, which are susceptible to Type II DM, were assigned to either concentrated PM 2.5 or filtered air (FA) for 4-8 weeks via a versatile aerosol concentrator and exposure system (n=7-8 for each group). PM 2.5 exposure led to hyperglycemia and insulin resistance, which were accompanied by increased hypothalamic IL-6, TNFα, and IKKβ mRNA expression and increased microglial/astrocyte reactivity. Targeting the NFκB pathway with intra-cerebroventricular administration of an IKKβ inhibitor (IMD-0354, n=8 for each group), but not TNFα blockade with infliximab (n=6) for each group), improved glucose tolerance, insulin sensitivity, rectified energy homeostasis (O 2 consumption, CO 2 production, respiratory exchanging ratio and heat generation) and reduced peripheral inflammation in response to PM 2.5 .

Conclusions: Central inhibition of IKKβ prevents PM 2.5 mediated peripheral inflammation and exaggeration of type II diabetes. These results provide novel insights into how air pollution may mediate susceptibility to insulin resistance and Type II DM.

Spatial patterns in wet and dry deposition of atmospheric mercury and trace elements in central Illinois, USA

An intensive 1-month atmospheric sampling campaign was conducted concurrently at eight monitoring sites in central Illinois, USA, from June 9 to July 3, 2011 to assess spatial patterns in wet and dry deposition of mercury and other trace elements. Summed wet deposition of mercury ranged from 3.1 to 5.4 μg/m(2) across sites for the total study period, while summed dry deposition of reactive mercury (gaseous oxidized mercury plus particulate bound mercury) ranged from 0.7 to 1.6 μg/m(2), with no statistically significant differences found spatially between northern and southern sites. Ratios of summed wet to summed dry mercury deposition across sites ranged from 2.2 to 4.9 indicating that wet deposition of mercury was dominant during the study period. Volume-weighted mean mercury concentrations in precipitation were found to be significantly higher at northern sites, while precipitation depth was significantly higher at southern sites. These results showed that substantial amounts of mercury deposition, especially wet deposition, occurred during the study period relative to typical annual wet deposition levels. Summed wet deposition of anthropogenic trace elements was much higher, compared to summed dry deposition, for sulfur, selenium, and copper, while at some sites summed dry deposition dominated summed wet deposition for lead and zinc. This study highlights that while wet deposition of Hg was dominant during this spring/summer-season study, Hg dry deposition also contributed an important fraction and should be considered for implementation in future Hg deposition monitoring studies.

Long-term exposure to concentrated ambient PM2.5 increases mouse blood pressure through abnormal activation of the sympathetic nervous system: a role for hypothalamic inflammation

BACKGROUND

Exposure to particulate matter≤2.5 μm in diameter (PM2.5) increases blood pressure (BP) in humans and animal models. Abnormal activation of the sympathetic nervous system may have a role in the acute BP response to PM2.5 exposure. The mechanisms responsible for sympathetic nervous system activation and its role in chronic sustenance of hypertension in response to PM2.5 exposure are currently unknown.

OBJECTIVES

We investigated whether central nervous system inflammation may be implicated in chronic PM2.5 exposure-induced increases in BP and sympathetic nervous system activation.

METHODS

C57BL/6J mice were exposed to concentrated ambient PM2.5 (CAPs) for 6 months, and we analyzed BP using radioactive telemetric transmitters. We assessed sympathetic tone by measuring low-frequency BP variability (LF-BPV) and urinary norepinephrine excretion. We also tested the effects of acute pharmacologic inhibitors of the sympathetic nervous system and parasympathetic nervous system.

RESULTS

Long-term CAPs exposure significantly increased basal BP, paralleled by increases in LF-BPV and urinary norepinephrine excretion. The increased basal BP was attenuated by the centrally acting α2a agonist guanfacine, suggesting a role of increased sympathetic tone in CAPs exposure-induced hypertension. The increase in sympathetic tone was accompanied by an inflammatory response in the arcuate nucleus of the hypothalamus, evidenced by increased expression of pro-inflammatory genes and inhibitor kappaB kinase (IKK)/nuclear factor-kappaB (NF-κB) pathway activation.

CONCLUSION

Long-term CAPs exposure increases BP through sympathetic nervous system activation, which may involve hypothalamic inflammation.

Cardiovascular depression in rats exposed to inhaled particulate matter and ozone: effects of diet-induced metabolic syndrome

BACKGROUND

High ambient levels of ozone (O3) and fine particulate matter (PM2.5) are associated with cardiovascular morbidity and mortality, especially in people with preexisting cardiopulmonary diseases. Enhanced susceptibility to the toxicity of air pollutants may include individuals with metabolic syndrome (MetS).

OBJECTIVE

We tested the hypothesis that cardiovascular responses to O3 and PM2.5 will be enhanced in rats with diet-induced MetS.

METHODS

Male Sprague-Dawley rats were fed a high-fructose diet (HFrD) to induce MetS and then exposed to O3, concentrated ambient PM2.5, or the combination of O3 plus PM2.5 for 9 days. Data related to heart rate (HR), HR variability (HRV), and blood pressure (BP) were collected.

RESULTS

Consistent with MetS, HFrD rats were hypertensive and insulin resistant, and had elevated fasting levels of blood glucose and triglycerides. Decreases in HR and BP, which were found in all exposure groups, were greater and more persistent in HFrD rats compared with those fed a normal diet (ND). Coexposure to O3 plus PM2.5 induced acute drops in HR and BP in all rats, but only ND rats adapted after 2 days. HFrD rats had little exposure-related changes in HRV, whereas ND rats had increased HRV during O3 exposure, modest decreases with PM2.5, and dramatic decreases during O3 plus PM2.5 coexposures.

CONCLUSIONS

Cardiovascular depression in O3- and PM2.5-exposed rats was enhanced and prolonged in rats with HFrD-induced MetS. These results in rodents suggest that people with MetS may be prone to similar exaggerated BP and HR responses to inhaled air pollutants.

Air pollution-mediated susceptibility to inflammation and insulin resistance: influence of CCR2 pathways in mice

BACKGROUND

Epidemiologic and experimental studies support an association between PM2.5 exposure and insulin resistance (IR). Innate immune cell activation has been suggested to play a role in the pathogenesis of these effects.

OBJECTIVES

We sought to evaluate the role of CC-chemokine receptor 2 (CCR2) in PM2.5-mediated inflammation and IR.

METHODS

Wild-type C57BL/6 and CCR2-/- male mice were fed a high-fat diet and exposed to either concentrated ambient PM2.5 or filtered air for 17 weeks via a whole-body exposure system. We evaluated glucose tolerance and insulin sensitivity. At euthanasia, blood, spleen, and visceral adipose tissue (VAT) were collected, and inflammatory cells were measured using flow cytometry. We used standard immunoblots, immunohistochemical methods, and quantitative PCR (polymerase chain reaction) to assess pathways of interest involving insulin signaling, inflammation, and lipid and glucose metabolism in various organs. Vascular function was assessed using myography.

RESULTS

PM2.5 exposure resulted in whole-body IR and increased hepatic lipid accumulation in the liver, which was attenuated in CCR2-/- mice by inhibiting SREBP1c-mediated transcriptional programming, decreasing fatty acid uptake, and suppressing p38 MAPK activity. Abnormal phosphorylation levels of AKT, AMPK in VAT, and adipose tissue macrophage content in wild-type mice were not present in CCR2-/- mice. However, the impaired whole-body glucose tolerance and reduced GLUT-4 in skeletal muscle in response to PM2.5 was not corrected by CCR2 deficiency.

CONCLUSIONS

PM2.5 mediates IR by regulating VAT inflammation, hepatic lipid metabolism, and glucose utilization in skeletal muscle via both CCR2-dependent and -independent pathways. These findings provide new mechanistic links between air pollution and metabolic abnormalities underlying IR.

Ambient fine particulate matter and ozone exposures induce inflammation in epicardial and perirenal adipose tissues in rats fed a high fructose diet

Background

Inflammation and oxidative stress play critical roles in the pathogenesis of inhaled air pollutant-mediated metabolic disease. Inflammation in the adipose tissues niches are widely believed to exert important effects on organ dysfunction. Recent data from both human and animal models suggest a role for inflammation and oxidative stress in epicardial adipose tissue (EAT) as a risk factor for the development of cardiovascular disease. We hypothesized that inhalational exposure to concentrated ambient fine particulates (CAPs) and ozone (O₃) exaggerates inflammation and oxidative stress in EAT and perirenal adipose tissue (PAT).

Methods

Eight- week-old Male Sprague–Dawley rats were fed a normal diet (ND) or high fructose diet (HFr) for 8 weeks, and then exposed to ambient AIR, CAPs at a mean of 356 μg/m³, O₃ at 0.485 ppm, or CAPs (441 μg/m³) + O₃ (0.497 ppm) in Dearborn, MI, 8 hours/day, 5 days/week, for 9 days over 2 weeks.

Results

EAT and PAT showed whitish color in gross, and less mitochondria, higher mRNA expression of white adipose specific and lower brown adipose specific genes than in brown adipose tissues. Exposure to CAPs and O₃ resulted in the increase of macrophage infiltration in both EAT and PAT of HFr groups. Proinflammatory genes of Tnf-α, Mcp-1 and leptin were significantly upregulated while IL-10 and adiponectin, known as antiinflammatory genes, were reduced after the exposures. CAPs and O₃ exposures also induced an increase in inducible nitric oxide synthase (iNOS) protein expression, and decrease in mitochondrial area in EAT and PAT. We also found significant increases in macrophages of HFr-O₃ rats. The synergetic interaction of HFr and dirty air exposure on the inflammation was found in most of the experiments. Surprisingly, exposure to CAPs or O₃ induced more significant inflammation and oxidative stress than co-exposure of CAPs and O₃ in EAT and PAT.

Conclusion

EAT and PAT are both white adipose tissues. Short-term exposure to CAPs and O₃, especially with high fructose diet, induced inflammation and oxidative stress in EAT and PAT in rats. These findings may provide a link between air-pollution exposure and accelerated susceptibility to cardiovascular disease and metabolic complications.

The effect of acute exposure to coarse particulate matter air pollution in a rural location on circulating endothelial progenitor cells: results from a randomized controlled study

CONTEXT

Fine particulate matter (PM) air pollution has been associated with alterations in circulating endothelial progenitor cell (EPC) levels, which may be one mechanism whereby exposures promote cardiovascular diseases. However, the impact of coarse PM on EPCs is unknown.

OBJECTIVE

We aimed to determine the effect of acute exposure to coarse concentrated ambient particles (CAP) on circulating EPC levels.

METHODS

Thirty-two adults (25.9 ± 6.6 years) were exposed to coarse CAP (76.2 ± 51.5 μg m(-3)) in a rural location and filtered air (FA) for 2 h in a randomized double-blind crossover study. Peripheral venous blood was collected 2 and 20 h post-exposures for circulating EPC (n = 21), white blood cell (n = 24) and vascular endothelial growth factor (VEGF) (n = 16-19) levels. The changes between exposures were compared by matched Wilcoxon signed-rank tests.

RESULTS

Circulating EPC levels were elevated 2 [108.29 (6.24-249.71) EPC mL(-1); median (25th-75th percentiles), p = 0.052] and 20 h [106.86 (52.91-278.35) EPC mL(-1), p = 0.008] post-CAP exposure compared to the same time points following FA [38.47 (0.00-84.83) and 50.16 (0.00-104.79) EPC mL(-1)]. VEGF and white blood cell (WBC) levels did not differ between exposures.

CONCLUSIONS

Brief inhalation of coarse PM from a rural location elicited an increase in EPCs that persisted for at least 20 h. The underlying mechanism responsible may reflect a systemic reaction to an acute "endothelial injury" and/or a circulating EPC response to sympathetic nervous system activation.

Reduced metabolic insulin sensitivity following sub-acute exposures to low levels of ambient fine particulate matter air pollution

Epidemiological studies suggest that fine particulate matter (PM2.5) may increase the risk for developing diabetes mellitus (DM). To evaluate possible mechanisms explaining these associations, we investigated if sub-acute ambient-level exposures can impair insulin sensitivity. Twenty-five healthy adults living in rural Michigan were transported to an urban location for 5 consecutive days (exposure-block) of daily 4- to 5-hour-long ambient air pollution exposures. Health outcomes, including the homeostasis model assessment of insulin resistance (HOMA-IR) the primary outcome of insulin sensitivity, were measured at 3 time points in relation to exposure-blocks: 7days prior to start; on the last exposure-day; and 7days after completion. PM2.5 was monitored at the urban exposure site and at community monitors near subjects' residences. We calculated 3 "sub-acute" exposure periods (approximately 5-days-long) starting retrospective from the time of health outcome measurements (PM2.5 ranges: 9.7±3.9 to 11.2±3.9μg·m(-3)). A 10μg·m(-3) increase in sub-acute PM2.5 exposures was associated with increased HOMA-IR (+0.7, 95% confidence interval (CI) 0.1 to 1.3; p=0.023) and reduced heart rate variability (standard deviation of normal-to-normal intervals [-13.1ms, 95%CI -25.3 to -0.9; p=0.035]). No alterations in other outcomes (inflammatory markers, vascular function) occurred in relation to PM2.5 exposures. Our findings suggest that ambient PM2.5, even at low levels, may reduce metabolic insulin sensitivity supporting the plausibility that air pollution could potentiate the development of DM.

A. actinomycetemcomitans LPS Enhances Foam Cell Formation Induced by LDL

The objective of this study was to examine whether native low-density lipoprotein (LDL) induces foam cell formation by macrophages and to examine the effect of lipopolysaccharide (LPS) on native LDL-induced foam cell formation by macrophages in vitro. RAW 264.7 cells were cultured with LDL or high-density lipoprotein (HDL) in the presence of LPS derived from Aggregatibacter actinomycetemcomitans. Foam cell formation was determined by staining with Oil-red-O to visualize cytoplasmic lipid droplet accumulation. The expression of LDL-receptor and the degree of internalization of FITC-conjugated LDL in RAW 264.7 cells were examined by immunofluorescence microscopy. The images were digitally recorded and analyzed with Image J software. Statistical analysis was performed by JMP software. Foam cell formation was induced by the addition of native LDL in dose- and time-dependent manners, whereas HDL showed no effect. LPS enhanced the foam cell formation induced by native LDL. In addition, LPS stimulated the expression of LDL-receptor protein on RAW 264.7 cells and enhanced the internalization of LDL. The enhancement of foam cell formation induced by LPS and LDL was inhibited by the depolymerizing agent nocodazole and amiloride analog 5-(N-ethyl-N-isoprophyl) amiloride (EIPA). Our findings indicate that LPS plays an important role in foam cell formation by LDL-stimulated macrophages.

Divergent effects of urban particulate air pollution on allergic airway responses in experimental asthma: a comparison of field exposure studies

BACKGROUND

Increases in ambient particulate matter of aerodynamic diameter of 2.5 μm (PM2.5) are associated with asthma morbidity and mortality. The overall objective of this study was to test the hypothesis that PM2.5 derived from two distinct urban U.S. communities would induce variable responses to aggravate airway symptoms during experimental asthma.

METHODS

We used a mobile laboratory to conduct community-based inhalation exposures to laboratory rats with ovalbumin-induced allergic airways disease. In Grand Rapids exposures were conducted within 60 m of a major roadway, whereas the Detroit was located in an industrial area more than 400 m from roadways. Immediately after nasal allergen challenge, Brown Norway rats were exposed by whole body inhalation to either concentrated air particles (CAPs) or filtered air for 8 h (7:00 AM - 3:00 PM). Both ambient and concentrated PM2.5 was assessed for mass, size fractionation, and major component analyses, and trace element content. Sixteen hours after exposures, bronchoalveolar lavage fluid (BALF) and lung lobes were collected and evaluated for airway inflammatory and mucus responses.

RESULTS

Similar CAPs mass concentrations were generated in Detroit (542 μg/m3) and Grand Rapids (519 μg/m3). Exposure to CAPs at either site had no effects in lungs of non-allergic rats. In contrast, asthmatic rats had 200% increases in airway mucus and had more BALF neutrophils (250% increase), eosinophils (90%), and total protein (300%) compared to controls. Exposure to Detroit CAPs enhanced all allergic inflammatory endpoints by 30-100%, whereas inhalation of Grand Rapids CAPs suppressed all allergic responses by 50%. Detroit CAPs were characterized by high sulfate, smaller sized particles and were derived from local combustion sources. Conversely Grand Rapids CAPs were derived primarily from motor vehicle sources.

CONCLUSIONS

Despite inhalation exposure to the same mass concentration of urban PM2.5, disparate health effects can be elicited in the airways of sensitive populations such as asthmatics. Modulation of airway inflammatory and immune responses is therefore dependent on specific chemical components and size distributions of urban PM2.5. Our results suggest that air quality standards based on particle speciation and sources may be more relevant than particle mass to protect human health from PM exposure.