Elevated PCBs Associated with Increased Risk of Cardiovascular Disease

MedicalResearch.com Interview with:

Monica Lind, PhD, Professor, Environmental toxicologistOccupational and Environmental MedicineUppsala University HospitalVisiting adress: Dag Hammarskjölds väg 60Uppsala Sweden 

Dr. Lind

Monica Lind, PhD,
Professor, Environmental toxicologist
Occupational and Environmental Medicine
Uppsala University Hospital
Visiting adress: Dag Hammarskjölds väg 60
Uppsala Sweden

MedicalResearch.com: What is the background for this study?

Response: Previous studies in workers exposed to very high levels of polychlorinated biphenyls (PCBs) have suggested hazardous health effects. However, circulating PCB levels are detected in almost all indivuduals in industrialized countries, but the health effects of moderately elevated levels as seen in the general population are not well established.

We investigated levels of PCBs in around 1,000 individuals, all aged 70 years, randomly chosen from the City of Uppsala, Sweden.

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Chemicals in Household Dust May Promote Fat-Cell Development

MedicalResearch.com Interview with:

Christopher D. Kassotis, Ph.D.NRSA Postdoctoral Research ScholarStapleton LabDuke UniversityNicholas School of the EnvironmentDurham, NC 27708 

Dr. Kassotis

Christopher D. Kassotis, Ph.D.
NRSA Postdoctoral Research Scholar
Stapleton Lab
Duke University
Nicholas School of the Environment
Durham, NC 27708 

MedicalResearch.com: What is the background for this study? What are the main findings?

  • So this was something that Heather Stapleton had been curious about for years, as she’s been one of several researchers characterizing the hundreds of chemicals that have been measured in indoor house dust. Before I came to Duke, one of her PhD students had measured the ability of many common indoor contaminants to activate the peroxisome proliferator activated receptor gamma (PPARg). The majority of these chemicals did, often quite well, which led to them testing indoor house dust extracts, also finding that the majority of dust extracts were also able to do so at very low levels. As PPARg is often considered the master regulator of fat cell development, the next obvious question was whether these common contaminants (and house dust) could promote fat cell development in cell models. My first work at Duke evaluated a suite of common indoor contaminants, finding that many of these chemicals could promote fat cell development, and that low levels of house dust extracts did as well.
  • We next explored this more systematically in a group of adults involved in a thyroid cancer cohort (this was just recently published in Science of the Total Environment:
  • In this study we evaluated the extent to which house dust extracts could promote fat cell development in a common cell model, and associated this with the metabolic health of adults living in these homes. We found that the greater extent of fat cell development was associated with significantly greater thyroid stimulating hormone concentrations (control residents only, with no evidence of thyroid dysfunction) and lower free triiodothyronine (T3) and thyroxine (T4). We further found a significant and positive association between extent of fat cell development and the body mass index (BMI) of all adults in the study. So this suggested that the indoor environment might play a role in the BMI and metabolic health of residents, and we next wondered if this would be more pronounced in children, who may be exposed to these contaminants during a critical window of development.
  • The next step, for our current work, was to substantiate these effects in a larger group of households, each with children.
  • Our major conclusions thus far have been that ~80% of house dust extracts promote significant fat cell development in a cell model – either via development from precursor cells into mature fat cells, measured via accumulation of lipids into the cells, or via the proliferation of those precursor fat cells. We also reported positive correlations of fat cell development with the concentrations of 70 different contaminants in the dust from these homes, suggesting that mixtures of contaminants are likely all acting weakly to produce these effects in combination. We’ve also begun to assess the other chemicals present in dust – chemistry can be either targeted (measuring concentrations of specific known chemicals in a sample), or non-targeted, where you try and determine the identity of the other chemicals in a sample. This has greater utility for identifying many more chemicals, though you will often not get chemical concentrations from this, nor absolute confirmed identification – just varying degrees of certainty based on evidence.

    Thus far we report approximately 35,000 chemicals in house dust samples across this study, and differential analyses have begun to pick out the few (less than 10 in each case) chemicals most differentially expressed between samples that exhibit high degrees of fat cell development in the lab vs inactive samples, for example, or which are differentially present in the homes of children categorized as obese or overweight. We are now working to confirm identity of these select contaminants that are more likely to be causative factors in the results we have observed.

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Triclosan in Household Dust Linked To Antibiotic Resistance

MedicalResearch.com Interview with:

Erica Marie Hartmann PhD Assistant Professor Dept. of Civil & Environmental Engineering Northwestern University Evanston, IL 60208

Dr. Erica Hartmann

Erica Marie Hartmann PhD
Assistant Professor
Dept. of Civil & Environmental Engineering
Northwestern University
Evanston, IL 60208

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The antimicrobial chemical triclosan has been found in almost every dust sample that has ever been tested worldwide, and we already know that triclosan can cause an increase in antibiotic resistance genes in wastewater. This study is the first to show a link between antibiotic resistance genes and antimicrobial chemicals in indoor dust, which people tend to come into contact with more than wastewater.

This finding is important because the World Health Organization has identified a huge information gap in community-acquired antibiotic-resistant infections; the use of antimicrobial chemicals in homes and other non-medical buildings could be contributing to the development of antibiotic resistance outside of hospital settings. This study was published in the wake of the FDA decision last week to ban the use of triclosan and several other antimicrobial chemicals in soaps. While the FDA decision is a good first step, it’s not the end the problem. Antimicrobial chemicals like triclosan are in a lot of different products. Right now, we don’t know how much of the triclosan we see in dust comes from soap vs. other products (building materials, paints, plastics, etc.).

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