Heart failure is a disease with increasing prevalence, while present treatment options, especially for heart failure with preserved ejection fraction (HFpEF), are inadequate. Hypertension and obesity-related metabolic dysfunctions are important risk factors for HFpEF development and progression. Nitro-oleic acid (NO2-OA) impacts metabolic processes by improving glucose tolerance and adipocyte function. We sought to unravel effects of NO2-OA on cardiac function. Mice were fed for 15 weeks with high fat diet combined with endothelial nitric oxide synthase inhibitor (L-NAME). During the last 4 weeks treatment with nitro-oleic acid or vehicle was administered via osmotic pumps. Finally mice were sacrificed, left ventricular tissue harvested, snapfrozen in liquid nitrogen and stored at -80°C until protein isolation.