Hill Lab
Recent Highlights
Publication!
7/8/2026
Kyle’s paper titled “Dietary branched-chain amino acids modify the cardiac growth response to exercise in male mice” was published in the Journal of Molecular and Cellular Cardiology. This study shows that circulating branched-chain amino acid levels increase transiently after a single bout of high-intensity exercise and that dietary BCAA availability can shape how the heart grows in response to exercise training. In male mice, a high-BCAA diet supported the expected increase in heart size after treadmill training, whereas a low-BCAA diet blunted this exercise-induced cardiac growth. Interestingly, exercise capacity improved regardless of diet, and female mice improved exercise capacity without showing significant cardiac growth. These findings suggest that nutrition can modify physiological cardiac remodeling and raise important questions about whether cardiac growth is required for improved exercise performance. We are continuing work to understand how metabolism and nutrition regulate exercise-induced cardiac remodeling and cardiovascular adaptation. Shown to the right is the Graphical Abstract, which illustrates the exercise training and dietary BCAA design, the changes in circulating BCAAs, and the effects of diet and exercise on exercise capacity and cardiac growth.
Publication!
7/8/2026
Daniel’s paper titled “TAK1 drives inflammatory fibroblast acquisition and shapes myocardial infarction responses in male mice” was published in Nature Communications. This study shows that TAK1 signaling in cardiac fibroblasts helps drive the formation of inflammatory fibroblasts after myocardial infarction. These fibroblasts produce chemokines, cytokines, and other injury-response signals that influence immune cell recruitment to the damaged heart. Deleting TAK1 specifically in fibroblasts reduced inflammatory cell recruitment after myocardial infarction and was associated with improved cardiac remodeling and function in male mice. The findings of this study help define how fibroblasts regulate inflammation after cardiac injury and identify TAK1 as an important signaling node linking fibroblast activation, immune cell recruitment, and post-infarction remodeling. We are continuing work to understand how fibroblast inflammatory signaling regulates cardiac repair and how these pathways may be targeted to improve outcomes after myocardial infarction.
Publication!
7/10/2025
Collin's paper titled "Pyruvate kinase splice variants in fibroblasts influence cardiac remodeling after myocardial infarction in male mice" was published in the Journal of Molecular and Cellular Cardiology. This study shows that the pyruvate kinase splice variant, Pkm2, is increased in the post-infarcted heart and that switching of the less enzymatically active Pkm2 variant with the more active Pkm1 variant improves ventricular remodeling after myocardial infarction in male mice. The findings of this study provide yet another example of how changes in metabolism can regulate fibroblast biology and cardiac remodeling after myocardial infarction. Collin has now left the laboratory for an exciting postdoctoral position in Dr. Tim McKinsey's laboratory at the University of Colorado. We are continuing work to understand how changes in glucose metabolism regulate fibroblast fate and function and influence ventricular remodeling. Shown to the right is an image of infarcted heart tissue, with Pkm2 staining (red) shown in areas of replacement fibrosis. The green staining (alpha-sarcomeric actin) indicates the presence of cardiomyocytes.
Kara and Collin go "back-to-back" to defend their dissertations!
5/29/25 and 5-30-2025
Kara Gouwens (MD/PhD student) and Collin Wells (PhD student) defended their respective theses on May 29th and May 30th. Both did very well. Kara defended her dissertation on the role of cardiac ketone body oxidation on myocardial hyperemia and exercise performance, and Collin defended his work on the role of metabolism in cardiac fibroblast phenotype and function. Both of these fine scientists have bright futures ahead. Next stops: Kara will enter her M3 year of medical school, and Collin will be heading to the University of Colorado for a postdoctoral position in the laboratory of Dr. Tim McKinsey. These two, along with Dan Nguyen, are the major hitters in our lineup. They will be missed!
Publication!
5-28-2025
Kara's paper was published in Circulation Research. This study shows that cardiac ketone body oxidation is required for hyperketonemia-induced improvements in exercise capacity. The study used a commercially available and widely used ketone body supplement and showed that its effects on exercise performance are underpinned by the ability of the heart to metabolize 3-hydroxybutyrate.
Hooding!
5-09-2025
Daniel was hooded! He will now move to his M3 year of the MD/PhD program. Selfishly, we will miss Dan, but we are excited to see him continue to succeed!
Publication!
2-14-2025
Daniel's paper titled, "Dietary Branched‐Chain Amino Acids Modify Postinfarct Cardiac Remodeling and Function in the Murine Heart" was published in Journal of the American Heart Association. This study provides proof‐of‐principle using a preclinical mouse model that dietary constituents can have marked effects on cardiac remodeling after myocardial infarction.
Successful Defense!
2-12-2025
Congratulations to Daniel Nguyen, who successfully defended his dissertion today! He will be returning to medical school to complete the rest of his MD/PhD training. The man is a beast (in the best possible way!) and he will be a stellar physician-scientist!
Publication!
12-12-2024
Kara's paper titled, "Myocardial Hyperemia via Cardiomyocyte Catabolism of β-Hydroxybutyrate" was published in Arteriosclerosis, Thrombosis, and Vascular Biology. This study shows that the circulating ketone, β-Hydroxybutyrate, increases myocardial perfusion and that its hyperemic effects are dependent on cardiomyocyte catabolism. The article was chosen for the cover image of the journal, with a local artist, Mr. Trevor Inkwell, kindly providing his artwork titled "Main Squeeze."
Publication!
01-2025
Tyler Jobe's paper titled, "Phase partitioning of the neutrophil oxidative burst is coordinated by accessory pathways of glucose metabolism and mitochondrial activity" was published in The Journal of Biological Chemistry. This study shows how neutrophils leverage multiple metabolic pathways to titrate the oxidative burst. This study is an example of the highly collaborative environment in the Center for Cardiometabolic Science. Tyler is a student of Dr. Marcin Wysoczynski, with whom we have collaborative projects.
