Abstract Body (Do not enter title and authors here): Introduction
Adenine has been demonstrated to be involved in the development of diabetic kidney disease. We postulate that adenine may play a similar role in the progression of cardiovascular disease. The underlying metabolic changes in ischemic cardiomyopathy (ICM) progression are not fully understood and may present novel targets to mitigate ischemic heart injury. This study aims to identify common metabolic targets based on adenine metabolism in both coronary artery calcification and ICM.
Methods
Coronary arteries from human donor hearts with and without calcification were analyzed by mass spectrometry imaging (MSI) and serial section von Kossa’s staining for image co-registration with identified metabolites. Bulk tissue LC-MS of the same artery samples were measured for adenine pathway metabolites. Another cohort of human heart tissues from healthy donors and those with a history of ICM were analyzed for bulk left ventricle tissue LC-MS measurement of adenine pathway metabolites. Further, to evaluate a mechanistic role for adenine in the development of ICM, a rat model of MI was studied with and without pharmacologic inhibition of MTAP, the enzyme responsible for adenine production. Infarct size was used as the readout of heart injury.
Results
An untargeted analysis by MSI reveals an increase in adenine highly localized to arterial calcification as well as other metabolites such as glycolytic intermediates and C16 ceramide-derived lipids. Bulk tissue LC-MS showed calcified arteries have an overall increase in adenine, 5’-methylthioadenosine (MTA), S- adenosylmethionine (SAM). Left ventricle tissue from human donors with a history of ICM showed a significant increase in adenine by bulk LC-MS compared to controls (t-Test, **p<0.01). There was a negative correlation of heart adenine with LVEF (Pearson R = -0.6807, **p<0.01). In a rat model of MI, inhibition of MTAP resulted in significantly reduced infarct size (from 50% to 10%, t-Test, *p<0.05).
Conclusion
Spatial metabolomics revealed increased adenine, several glycolytic intermediates, and C16 ceramide-derived lipids as highly co-localized to arterial calcification. Further, adenine was found to be increased in LV tissues with ICM and was negatively correlated with LVEF. Inhibition of adenine production reduced infarct size in a rat model of MI by >80%. Taken together, multimodal metabolomics reveals adenine to be mechanistically involved in cardiovascular disease and presents as a novel therapeutic target.