Urolithin A Provides Cardioprotection and Mitochondrial Quality Enhancement Preclinically and Improves Cardiovascular Health Biomarkers in Humans
Cardiovascular diseases (CVDs) remain the primary cause of global mortality. Nutritional interventions hold promise to reduce CVD risks in an increasingly aging population. However, few nutritional interventions are proven to support heart health and act mostly on blood lipid homeostasis rather than at cardiac cell level.  Here, we show that mitochondrial quality and dysfunction are a common hallmark in human cardiomyocytes upon heart aging and in chronic conditions. Preclinically, the post-biotic and mitophagy activator, Urolithin A (UA), reduced both systolic and diastolic cardiac dysfunction in models of natural aging and heart failure. At a cellular level, this was associated with a recovery of mitochondrial ultrastructural defects and mitophagy. In humans, UA supplementation for 4 months in healthy older adults significantly reduced plasma ceramides clinically validated to predict CVD risks. These findings extend and translate UA's benefits to heart health, making UA a promising nutritional intervention to support cardiovascular function as we age. Overall design: Fifty Wistar male rats were purchased from Janvier Labs (France). Animals were collectively housed in cages at SYNCOROSOME's facilities and had free access to food (RM1, SDS Dietex) and drinking water ad libitium.  Surgery was initiated in 7-week-old rats that were separated into three groups. MI was induced in animals from Surgery Vehicle (n=20) and Surgery UA (n=20), by chronic left anterior descending coronary artery (LAD) ligation performed at day 0. Rats were anesthetized by an intraperitoneal injection (IP) of Medetomidine (0.5 mg/kg) and Ketamine (50mg/kg). The animals were then intubated and ventilated at 10 ml/kg tidal volume and 70-80 cycles/minutes. The body temperature was maintained around 37°C using a thermoregulated heating pad connected to a rectal probe. Rats were placed in supine position, chest-shaved and prepared for standard surgical aseptic conditions. A left lateral thoracotomy was carefully performed to expose the heart. Suture was placed around the LAD (4/0 Silk, Ethicon), around 2 mm below the left atrium and close to the interventricular junction, to obtain infarct size (IS) near 40% of the total left ventricular (LV) area. The chest was closed, air was expelled from the rib cage to avoid pneumothorax and quick reanimation was performed using atipamezole hydrochloride (IM, 0,5 mg/ml, Zoetis). The sham vehicle animals (n=10) were subjected to the same protocol. However, after the left lateral thoracotomy exposing the heart, the rib cage was closed without passing the suture thread around LAD.  A peri-operative care of the animals was performed during the surgery. For 8 weeks, starting 24 hours after the surgery UA animals were daily treated with Urolithin A at 50 mg/ml by oral gavage. The rats from sham vehicle and surgery vehicle group received the same dose of a vehicle solution (0.5% carboxymethylcellulose) at the same time. The volume of administration was adjusted every week based on the mean body weight.  One day after the last dosing, overnight-fasted rats were anesthetized with 2.5% isoflurane in 50% O2  50% air mixture followed by an injection of buprenorphine (0.03mg/kg). Hearts were stopped in diastole (KCL 2M, 1ml/kg) by jugular injections. The atria were removed, the hearts were washed in cold PBS and quickly sponged to remove the liquid from the ventricles. LV was separated from the remaining part of the heart, weighed and incubated in NBF 10% for 48h. Hearts were transferred in ethanol 70%, cut in three transverse sections and embedded in paraffin in three different blocks, deriving from apical, middle and basal LV regions (Group 1, N=10, group2 and N=20).