Aruni Bhatnagar

Director, Christina Lee Brown Envirome Institute
Professor, School of Medicine

Posted: April 30, 2025

For Aruni Bhatnagar, cardiovascular health has always been at the heart of the matter.

A professor at the University of Louisville School of Medicine, Bhatnagar’s interest in the heart and physiology began while he was growing up. But after losing his father to a sudden cardiac event when Bhatnagar was 19 years old, he found a personal motivation to pursue answers on why people develop heart disease and what could be done to solve those issues.

Bhatnagar came to the U.S. from his native India after receiving a PhD in chemistry and conducted his post-doctoral training at a university in Galveston, Texas, known as a top school for studying cardiac arrythmias — a leading cause of sudden cardiac events. He remained a Texan for 14 years and, when it came time to consider his next move, UofL wasn’t even on his radar. But a positive recruitment effort from the university and Bucks-for-Brains, a program championed by former Kentucky governor Paul E. Patton to bring world-class researchers to Kentucky, made the possibilities at UofL more visible and Bhatnagar followed his heart.

“I didn’t know where Louisville was on the map,” Bhatnagar said. “I had offers from five other universities and two were seriously pursuing me, but the resources UofL offered – and the Bucks-for-Brains program – made UofL very attractive.”

Now, 25 years later (“I’ve been in Louisville longer than India,” Bhatnagar jokes), a score of research achievements and two prominent posts as chief of the division of environmental medicine and director of UofL’s Christina Lee Brown Envirome Institute have proven that Bhatnagar and Louisville were a perfect match.

The department of environmental medicine was formed in 2018 and is a leading national program in that discipline thanks to Bhatnagar’s stewardship and the department’s unique perspective on what makes up the collective environment we exist within and create for ourselves. Bhatnagar noted that up to 70-80% of heart diseases and 97% of known cancers are non-genetic, positioning environmental medicine to focus on the environmental factors that contribute to disease generation, risk and remediation.

“We need to understand the environment as a multidomain entity,” Bhatnagar said. “There has not been such a comprehensive view of the environment done anywhere else like what we are doing here at UofL.”

It’s that type of outside-the-paradigm thinking that led Bhatnagar to develop one of the crown jewels of his research career thus far – the Green Heart Project.

The Green Heart Project, an Envirome Institute clinical trial where trees are medicine, addressed how improving air quality can enhance community health outcomes. The seed of the idea for the project came from weighing what the options would be to lower air pollution in Louisville, a city with historically poor air quality (just ask anyone during allergy season). Bhatnagar said researchers had two options to solve the issue. One, argue for things like emission regulations, cleaner cars or a reduction in coal plants – each difficult to achieve and each not enough to alleviate the issue. The second option? Getting their hands dirty.

“It started as a joke that maybe we could plant a lot of trees because of some studies indicating that trees could be good in preventing air pollution,” Bhatnagar said. It was assumed that greener spaces have lower levels of pollution, but there were no studies showing that through a health lens. At first, Bhatnagar thought the study would not be viable because a researcher would need 30 years or more for trees to mature so the study could be properly conducted. But a conversation with environmental nonprofit The Nature Conservancy, who said, yes, mature trees can be planted, changed everything and allowed Bhatnagar’s research to take root.

Greening the study’s zone in South Louisville began in 2019 through collaboration with The Nature Conservancy, who raised over $8 million to fund the tree purchase and planting. Ultimately, over 8,000 trees were planted in parks, on private properties and along the Watterson Expressway that bisects the area. The study’s findings were released in 2024, revealing that residents who lived in the green-intervention zones showed lower levels of markers of inflammation used to identify and diagnosis diseases associated with cardiovascular health, among others.

“Before the Green Heart Project, I have not found anybody, anyplace, anywhere conducing evidence-based planting directed toward improving the health of people,” Bhatnagar said. Now, he receives calls from leaders in places as far away Sao Paolo, Brazil, or Sydney, Australia, interested in bringing the same health-enhancing greening measures to their cities. With the results his research has been able to produce, Bhatnagar hopes the Green Heart Project will encourage others to plant their city landscapes to promote better air quality and protect their communities.

Here at home, Bhatnagar said that UofL has made a very concerted effort to engage the community, even long before the Green Heart Project.

“We went to the community, and we talked to people. That built the trust that we are going to be here with you,” he said, adding that UofL’s charter is to be a premier metropolitan university focused on research and innovation to serve the community. And it isn’t charity – it’s collaboration. It’s building trust to create knowledge that not only benefits Louisville but the rest of the world as well.

“That’s the type of model the university has created, and I think that’s very gratifying and makes it such a great place to work. You can’t do this work anywhere else. We have a small enough city to really know each other, and we are a good community, and we can do big things,” Bhatnagar said. “And I think UofL is the right place to do big things.”