LONDON / RankWire.AI / – A naturally occurring compound linked to pomegranates has improved several measures of heart function in experimental models of HFpEF. The compound, urolithin A, helped the heart relax more effectively between beats. It also reduced fibrosis and abnormal enlargement of heart muscle cells. Some measurements improved by as much as 80% compared with untreated animal models. Researchers also recorded benefits in engineered human heart tissue, adding another layer of laboratory evidence to the findings.
HFpEF, or heart failure with preserved ejection fraction, develops when the heart can still pump normally but cannot relax properly. That limits how well the chambers fill with blood between contractions. Patients can experience breathlessness, fatigue and reduced exercise capacity. The condition accounts for about half of heart failure cases in the United Kingdom. Urolithin A forms when gut microbes process certain compounds found in pomegranates, walnuts and several berries, although production differs from person to person.
Researchers traced the effect to PKGIα, a protein that supports normal blood vessel function and heart muscle relaxation. Urolithin A modified a specific part of the protein known as cysteine 42. That action activated a pathway linked to cardiovascular function. The study also examined how the compound affected the structure of heart tissue. King’s College London researchers reported better diastolic function, less tissue scarring and reduced enlargement of heart muscle cells in treated experimental models.
Urolithin A improved heart relaxation in laboratory models
The animal findings focused on diastolic function, which measures how well the heart relaxes and fills after each contraction. Treated models showed better performance across several measures than untreated controls. Researchers also found lower levels of fibrosis, which can make heart tissue stiffer and impair filling. The reported improvement of up to 80% applied to selected experimental measurements. It did not mean patients experienced an 80% improvement, and the research did not test clinical outcomes in people.
The team also tested urolithin A in engineered human heart tissue made from stem cells. These laboratory models allow scientists to study human cardiac tissue under controlled conditions. The compound improved both relaxation and contraction patterns in those samples. Earlier human studies of urolithin A for other uses have reported a favorable safety profile. The new heart failure research did not include patients with HFpEF, so its findings remain based on animal models and engineered human tissue.
Human trials are still needed to test heart failure benefits
The British Heart Foundation funded the research and highlighted the compound’s effect on heart relaxation in early-stage testing. The organization also noted that the findings do not establish a treatment for people with HFpEF. Researchers cautioned against reading the results as proof that eating pomegranates can treat heart failure. The study examined urolithin A and its biological activity, not dietary pomegranate consumption. No food tested in the research showed an ability to prevent or treat heart failure.
The work identifies PKGIα cysteine 42 as a specific biological target in HFpEF research. It also provides laboratory evidence that urolithin A can activate that pathway and improve several markers tied to cardiac relaxation. HFpEF often occurs alongside high blood pressure, obesity and diabetes. The condition remains a major form of heart failure worldwide. Clinical trials would need to test whether the compound produces similar effects in patients and whether those effects translate into measurable health benefits.