USC study shows persistent organic pollutants are associated with higher blood pressure in teenagers after weight loss surgery

Researchers from the Keck School of Medicine of USC have found that persistent organic pollutants (POPs)—synthetic toxic chemicals often found in food sources and stored in body fat — are associated with long term higher blood pressure in adolescents who have undergone bariatric surgery, a weight-loss intervention.

The study, funded by the National Institutes of Health and published in the ACS journal Environmental Science & Technology, suggested that POPs diminished the beneficial effect of bariatric surgery on improved blood pressure due to disruptions in lipid metabolism, which is how the body processes fat. The researchers also identified a plausible biological pathway explaining the relationship between POPs and changes in blood pressure.

These findings could eventually lead to treatments to reduce adverse health effects of exposure to these environmental chemicals on individuals with obesity, particularly for those pursuing weight-loss interventions such as bariatric surgery.

“While bariatric surgery is an effective treatment used to address severe obesity and improve cardiometabolic health, it also releases POPs stored in fat into the bloodstream,” says Shudi Pan, the study’s first author and a fourth year PhD candidate in the Department of Population and Public Health Sciences at Keck School of Medicine of USC. 

Although their toxicity led many countries to start restricting the use of POPS more than 20 years ago, they remain a global health challenge since they persist for long periods in the environment. They have been detected at concerning levels worldwide even in regions where these chemicals were never manufactured or used.  

“POPs are considered an emerging risk factor for hypertension and our study provided us a unique opportunity to evaluate the relationship between POPs exposure and blood pressure. Until now, few studies have examined how POPs exposures in adipose tissue affect blood pressure,” says Pan. “Similarly, the mechanisms underlying the relationship between POP mixtures and blood pressure have been unclear.” 

The study included data from 57 adolescents from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) consortium, who underwent bariatric surgery.

“We measured the level of POPs stored in adipose tissue before surgery. After, we assessed whether it affected blood pressure in the short term—at 6 months, and then five years after surgery,” says Pan.

Pan’s research found that POPs mixtures were linked to higher systolic blood pressure five years after bariatric surgery. Additionally, the researchers incorporated metabolomics to understand the underlying mechanisms of POP mixtures in adipose tissue on changes in blood pressure. Metabolomics refers to the study of metabolites which are small molecules or substances made when the body breaks down food, chemicals, or its own tissue—in this case the breakdown of body fat after bariatric surgery. 

“Through a technique called high-resolution mass spectrometry, we assessed these metabolites, thousands at a time, to determine what complex biological changes were occurring that led to changes in blood pressure,” says Pan. 

The researchers’ analysis revealed that one particular pathway involved in the production of prostaglandin was key in influencing blood pressure changes in the long-term, making this one of the first studies to identify a plausible rationale. Prostaglandin has long been proved to be involved in blood pressure regulation, and this study found that POPs modified prostaglandin pathways, contributing to disruptions in blood pressure regulations. 

“While our study had a small sample size, we think the prostaglandin pathway is a key player in understanding the biological mechanism between POPs and the development of high blood pressure in this demographic and more research is needed to further understand this particular pathway linking POP exposures to blood pressure regulation,” says Pan. 

High blood pressure in adolescence is associated with an increased risk of cardiovascular disease and cardiovascular diseases mortality in adulthood. Interventions that can address early life hypertension can help reduce the risk of cardiovascular disease, which remains a leading cause of death worldwide. 

About this study

In addition to Pan, the study’s other authors are Zhenjiang Li, Brittney O. Baumert, Hongxu Wang, Jesse A. Goodrich, Sarah Rock, Erika Garcia, Max T. Aung, Sandrah P. Eckel, Rob McConnell, David V. Conti, and Lida Chatzi  from the Department of Population and Public Health Sciences, Keck School of Medicine of the University of Southern California; Douglas I. Walker and Catherine  E. Mullins from Emory University, Georgia;  Thomas H. Inge and Justin R. Ryder from Northwestern University, Illinois; Todd M. Jenkins and Stavra Xanthakos from the University of Cincinnati; Stephanie Sisley from Baylor College of Medicine, Texas; Scott M. Bartell from the University of California, Irvine; Xiangping Lin from Stanford University, California; Brooklynn McNeil from Columbia University, New York; Anna  R. Robuck from the Icahn School of Medicine at Mount Sinai, New York;   and Michele  A. LaMerill from the University of California, Davis. 

This work was primarily funded by a grant from the National Institute of Environmental Health Sciences (NIEHS) [R01ES030364]. Additional funding came from the National Institutes of Health [U01HG013288, R01ES030691, R01ES029944, and P30ES007048], the American Heart Association [24PRE1187910], and NIEHS [T32-ES013678, R01ES03069]. The Teen-LABS consortium is supported by cooperative agreements with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) through grants for a clinical coordinating center [UM1DK072493] and the Data Coordinating Center [UM1DK095710].