The Green Heart Louisville Project is a groundbreaking scientific study that is testing the hypothesis that introducing more green trees and shrubs into a neighborhood can directly lower the risk of cardiovascular disease, the leading cause of death worldwide.

“Receiving this award is a great honor not only for our investigators, but also our partners and communities,” said Aruni Bhatnagar, director of the at University of Louisville and project leader for Green Heart Louisville. “It validates years of work which has shown that thoughtfully planned greening can improve cardiovascular and community health, and it affirms that the Green Heart project is not only good science, but also a model for how to improve human health in urban environments. The recognition gives us new momentum to scale this work across Louisville and beyond.”

The Witte-Sakamoto Family Medal in City and Regional Planning was established in 2019 by William Witte, an alumnus of the Weitzman School, and his wife, Keiko Sakamoto to recognize a firm, team or professional for an exemplary plan that advances the field of plan making in at least four of the following areas: social equity, environmental quality, design, public health, mobility, housing affordability and economic development. The juries for the Witte-Sakamoto Family Medal and Prize were chaired by Megan Ryerson, UPS Foundation Chair of Transportation, chair of city and regional planning, and professor of city and regional planning and electrical and systems engineering at Weitzman.

“Green Heart Louisville exemplifies a holistic way of looking at public health – a marriage of design, planning and science to emulate,” said Fritz Steiner, dean and Paley Professor at Weitzman, and a member of the jury who selected Green Heart Louisville for the award.

Launched in 2018 by UofL’s Christina Lee Brown Envirome Institute with support from The Nature Conservancy, the study investigates whether and how living among more densely greened surroundings contributes to better heart health. The Green Heart team applied the treatment – the addition of thousands of mature trees and shrubs – to the center of a four-square-mile area in south Louisville.

The first clinical outcomes from the study, , indicate that people living in neighborhoods where the number of trees and shrubs was more than doubled showed lower levels of a blood marker of inflammation than those living in the control area. General inflammation is an important risk indicator for heart disease and other chronic diseases.

The Green Heart Project’s work to establish a scientific link between nature – specifically urban greenery – and human health is already influencing projects worldwide. The first clinical outcomes announcement garnered widespread national media attention. Many research papers, posters and talks on the project have been delivered to both scientists and laypeople since the project’s inception, and robust research and outreach for the project continues.

Scientists at UofL, along with colleagues from Boston University and the University of Massachusetts Lowell, have identified perfluorooctane sulfonate (PFOS) as a potential environmental factor that worsens alcohol-associated liver disease.

PFOS is a man-made chemical belonging to the group known as per- and polyfluoroalkyl substances (PFAS), often referred to as “forever chemicals” because they do not readily break down in the environment or the human body. These substances have been used for decades in products such as non-stick cookware, water-resistant clothing, fast-food packaging, stain-resistant carpets and upholstery, and firefighting foams. Their extensive use has led to widespread contamination in the environment. show that PFAS can be detected in approximately 95% of Americans, sparking increasing concern about their long-term health effects.

At the same time, alcohol consumption remains a significant global health issue. , and its consumption continues to rise globally. In the U.S. alone, excessive alcohol use is responsible for approximately 95,000 deaths annually, making it one of the leading causes of preventable death and a major contributor to liver disease.

“Given the increasing prevalence of alcohol consumption and the widespread presence of PFAS in the environment, many individuals who drink alcohol may be inevitably exposed to these persistent pollutants. This makes it critically important to study how combined exposures to alcohol and environmental chemicals like PFOS might influence liver health,” said Matthew Cave, UofL professor of medicine and publication co-author.

Although it is well known that both alcohol and PFOS cause liver damage individually, little has been understood about their combined effects until now. , indicating that additional factors such as genetics, sex, microbiome and environmental exposures may contribute to individual susceptibility.

“This work helps explain why two people with similar alcohol consumption may experience very different liver outcomes,” said Frederick Ekuban, assistant professor of medicine at UofL and first author of the study. “Environmental exposures like PFOS may be the missing link.”

Using animal models, the researchers simulated real-world exposures to both alcohol and PFOS. The study showed that co-exposure to alcohol and PFOS significantly increased fat accumulation and markers of liver damage, as well as clear signs of disrupted metabolism and activation of genes and pathways predicted to be associated with oxidative stress and cancer development.

In short, the study demonstrates that PFOS exposure can significantly worsen liver damage when combined with alcohol consumption. While this research used high levels of alcohol to understand the underlying mechanisms, the findings reveal important biological pathways that warrant further investigation across different drinking patterns.

The research team also found that PFOS interferes with the liver’s ability to manage fats, disrupts its natural protective and repair systems and activates pathways that promote liver injury.

“While the liver typically has a remarkable capacity to recover from alcohol-induced stress, PFOS appears to push that resilience beyond its limits, resulting in compounded and more severe damage,” said Jennifer Schlezinger professor of environmental health at Boston University and co-author of the publication.

Perhaps most concerning, the team discovered that 60% of all PFOS exposure ended up concentrated in the liver, exactly where alcohol damage occurs.

Ongoing research at UofL is examining how other PFAS compounds may interact with alcohol, whether males and females respond differently to these exposures and what the long-term consequences of combined exposures might be. The team is also exploring whether targeted therapies can be developed to prevent or mitigate this type of liver damage.

Although more studies are needed, people can take practical steps now to limit their exposure to PFAS. These include:

• Choose stainless steel or cast-iron cookware instead of non-stick pans
• Use water filters, especially in areas near industrial zones
• Avoid stain-resistant treatments on furniture and carpets
• Reduce consumption of packaged fast foods and microwave popcorn.
• Select household products with PFAS-free labels

Given that liver disease affects millions of Americans and is becoming more prevalent worldwide, the findings of this research support growing calls for stronger regulation and oversight of persistent chemical contaminants. By better understanding the hidden interactions between environmental toxicants and lifestyle behaviors, scientists and policymakers may be better equipped to prevent and treat liver disease.

��Article by Sarah Jump

DeJarnett has accepted a one-year fellowship as deputy director for environmental justice data and evaluation for the . The council coordinates the federal government’s efforts to improve, preserve and protect public health and the environment. It also advises the president and develops policies on climate change, environmental justice, federal sustainability, public lands, oceans and wildlife conservation.

DeJarnett is on leave from UofL for the one-year fellowship, but she will be working remotely, so she will remain in Louisville and stay connected with her UofL colleagues.

UofL News talked with about the fellowship and what she hopes to gain from the experience that she can bring back to UofL.

UofL News: What will be your role as deputy director for environmental justice data and evaluation?

�ٱ𴳲����Ա�ٳ�:��The White House Council on Environmental Quality (CEQ) has created the . Version 1.0 was , and we’re continuing to mold it with input from stakeholders across the U.S. and experts in the field. I will continue that process and engage people and experts around the tool. We are also developing an Environmental Justice Scorecard that will track government agencies’ progress on environmental justice.

I’m very excited to see how the information from these environmental justice tools will be used to identify communities across the U.S. that are disadvantaged and thereby uniquely susceptible to the health hazards of climate and environmental exposures, but ultimately how climate and environmental justice investments in these communities will benefit health.

My interest is in advancing environmental health for everyone, particularly the populations that have borne the greatest burden, that have frequently experienced these exposures and communities that may be less resilient to these health threats. I want to help equip those communities and ensure that future actions and activities and efforts to protect health do not leave certain groups behind. If marginalized communities do not benefit from these actions, then injustice continues to perpetuate.

UofL News:�� What is environmental justice?

DeJarnett: According to the Environmental Protection Agency, environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin or income with respect to the development, implementation and enforcement of environmental laws, regulations and policies. This goal will be achieved when everyone enjoys the same degree of protection from environmental and health hazards and have equal access to the decision-making process to have a healthy environment in which to live, learn and work.

UofL News: What are some examples of environmental injustice?

DeJarnett: ��I have a personal example. I’m from here in Kentucky, but the greater portion of my family is from Birmingham, Alabama, where my parents and my grandparents lived in an area of environmental injustice.

Their community was home to numerous steel mills. Some still are in the neighborhood today. Also, a major interstate runs right through their community, another interstate is south of it, the airport is just south of their neighborhoods, there were hazardous waste sites and so forth. There was documented soil contamination in their community that has been remediated. But the community continues to deal with poor air quality and there are a number of health disparities present – cardiovascular disease, low birth weight and other chronic conditions.

We have similar experiences right here in Louisville in Rubbertown, which at its height, had 11 to 13 chemical manufacturers in a community that’s largely populated by low-wealth individuals and people of color. Another example is in southeastern Louisiana in an area known as cancer alley.

Flint, Michigan’s water crisis and formerly redlined communities that have warmer surface temperatures, poorer air quality and are more flood prone are other examples.

You have places where there are large industrial exposures, hazardous waste sites or other environmental toxins that people are being exposed to and we often find that those happen to certain segments of our population. It could be on tribal lands; it could be communities of low wealth.

UofL News: What do you hope to contribute to the council’s mission?

DeJarnett: My interest overall is to contribute to the advancement of environmental justice for the advancement of public health. I am super excited that I may be able to contribute to actions, activities, resources and tools that could contribute to improved health across our nation, particularly for communities that bear a heavier burden and that have higher risk.

I hope to be able to make a difference for communities like that of my family in Birmingham and Rubbertown here in Louisville, in Mossville, Louisiana and all across the nation. These and other communities have not always been given a voice in their exposure to environmental burdens and are not able to – nor should they have to – just up and move.

We all deserve clean air to breathe, we all deserve safe water to drink, and I hope to contribute to activities that support upholding those rights.

UofL News: What in your previous experience makes this a perfect position for you?

DeJarnett: At UofL, I was doing research on climate change and health and was looking at extreme heat exposure and cardiovascular disease risk as well as poor air quality and cardiovascular disease risk. In addition, I was examining environmental health disparities.

Before I came to UofL, I worked at two national nonprofits, the American Public Health Association and the National Environmental Health Association. There I did a lot of work building partnerships and facilitating opportunities for multiple people to weigh in with their expertise and contribute to an end product.

I have appreciated opportunities to build consensus among national leaders and to identify emerging trends and share environmental health resources.

In this role I’ll need to work between agencies and be able to put on multiple hats and speak to multiple audiences. I love opportunities to try to meet people where they are, find what we have in common, what values we share and how can we move from there with shared vision.

UofL News: How will this experience be helpful to you and the mission of the Envirome Institute once you return to UofL?

DeJarnett: I will get a national picture of the current state of environmental justice research and data that exists and a deeper understanding of the gaps in knowledge in environmental health and environmental injustice across the U.S. This will help me understand where academic research may be able to fill those gaps.

In addition, this opportunity will expose me to environmental justice data tools that our communities can utilize to inform local action.

Our center is committed to human health, to improving, advancing and protecting health in our communities. Environmental justice is a key aspect of health in our community. Plus, I’ll get a lot of experience with data and analysis, and that always benefits in environmental epidemiologist.

I love being at the University of Louisville. I love the expansion and direction that’s happening right here within the Envirome Institute, so I’m grateful for the support to have this life-bridging opportunity and to be able to bring that back here.

Over the next six months, the , part of the Department of Urban and Public Affairs, will explore how the city of Louisville can serve as a living laboratory for research, education and experimentation at the Healthful City Design Studio at 429 W. Muhammad Ali Blvd. This temporary pop-up location, an addition to the current UDS location in the Portland neighborhood, offers a space in which community members can dive into issues and opportunities specific to the heart of downtown.

“This is an exciting opportunity to pull together the threads of urban planning and design, public health, equity, ecology, engineering, economics and more to focus on how these overlapping facets of the city can not only solve problems we face now, but also position our downtown and city for the future,” said UDS Director Patrick Piuma. “I believe we have the talented minds throughout our community to examine these aspects of our city, and our hope is to find ways to unlock the creativity needed to become a leader in this space.”

To kick off the pop-up, Piuma, alongside colleague and entrepreneur Sylvanus Hudson, will develop a series of events, workshops, demonstration projects and more to bring together professionals and the local community to explore how the built environment affects health and what it means to be a healthy city. The team will be joined by collaborators from other UofL departments, Louisville Metro Government, the University of Kentucky and related organizations and individuals as the direction of the initiative takes shape.

Early events and activities will be focused on outreach and education, getting people together to share ideas about what a healthy city looks like and collaborative demonstration projects to communicate the importance of cooling urban heat islands, improving air and water quality, planting trees and other vegetation, public safety, welcoming environments and the health benefits of reintroducing nature into urban environments.

“The pandemic has revealed the importance of the built environment on health and how valuable safe and healthy places are in promoting public health and resilience,” said Aruni Bhatnagar, director of the Christina Lee Brown Envirome Institute.

The goal of the effort will be to create a unique urban laboratory for innovation where UofL becomes a stronger partner with the community, public officials and others to develop novel solutions to the challenges our city faces. This initiative is an offshoot of the Downtown Revitalization Team’s Action Plan that calls for making downtown more vibrant, clean, safe and welcoming.

“It is critical for Louisville to invest in its natural and built environments to improve residents’ health, as well as be a competitive city in the 21^st Century,” said Jeff O’Brien, co-chief of Louisville Forward. “We can design our cities to prepare us for the changing climate and improve our health, all while making the city a more vibrant and equitable place.”

The UDS initiative will draw on past programs such as the Sustainable City Series’ public forums that raised awareness of sustainable practices and has led to place-making projects such as and .

The Healthful City Design Studio opens Monday, Nov. 8.

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The research, led by Aruni Bhatnagar, professor of medicine and director of the UofL Christina Lee Brown Envirome Institute, was published ahead of print in the .

Previous studies have shown that proximity to green space — trees and other vegetation — can lower blood pressure levels and the risk of heart disease. A number of environmental factors may come into play, including increased opportunity for outdoor exercise, reduced mental stress and socioeconomic status. However, the relationship between vascular (blood vessel) health, green space and air pollution has not been fully explored.

In this , researchers looked at the arterial stiffness of adult volunteers with co-occurring conditions such as obesity, high blood pressure, diabetes and high cholesterol, that put the volunteers in the moderate-to-severe risk category for heart disease.

“Although we have known for a long time that exposure to air pollution has adverse effects on our blood vessels, this study shows that those who live in greener neighborhoods may be less affected,” Bhatnagar said. “Therefore, one way of preventing the harmful health effects of air pollution may be to make neighborhoods more green.”

Using study participants’ residential addresses and data from the U.S. Geological Survey and local Environmental Protection Agency monitoring stations, the research team analyzed environmental factors where the volunteers lived, including:

• Vegetation index, including the amount of and variation in greenness levels within 200-meter and one-kilometer (0.62 miles) radii around each volunteer’s home.
• Particulate matter, tiny toxic particles invisible to the naked eye, in the air.
• Levels of ozone, a colorless, toxic gas and significant air pollutant.

At times when the particulate matter and ozone levels were high, participants had higher levels of arterial stiffness, however, those who lived in areas with more flora had better blood vessel function. Trees and other greenery offset vascular dysfunction that air pollution causes, the researchers explained.

In previous work, the researchers found that individuals who live in areas with a large amount of greenness show lower exposure to volatile chemicals and have greater household income. In the current study, they explored the relationships between greenery, air pollution and arterial stiffness and found a similar correlation between the U.S. Geological Survey’s normalized difference vegetation index and average household income. Even when adjusting for self-reported lifestyle habits such as exercise and smoking — 70% of the volunteers were nonsmokers — the researchers found that “the effects of green spaces on hemodynamic function are largely independent of median household income, physical activity levels and tobacco use.”

“These findings indicate that living in green areas may be conducive for vascular health and that the [favorable] effects of greenness may be attributable, in part, to attenuated exposure to air pollutants such as [particulate matter] and ozone,” said Daniel Riggs, UofL biostatistician and the study’s first author.

This research was conducted in conjunction with the Green Heart Project, a first-of-its-kind study of the effects of plants on human health, led by researchers at the .