Objectives:

Heart failure is the leading cause of morbidity and mortality worldwide, and its prevalence is steadily increasing. Despite progressively improved pharmacologic and surgical treatment options, including left ventricular assist device implantation (LVAD) and heart transplantation (HTx), knowledge of molecular mechanisms is still minimal. In this study, we performed a comparative proteomic analysis of myocardial tissue samples to elucidate whether the regional proteome repertoire reflects disease manifestations and to decipher etiologic proteotypic factors that eventually offer novel treatments.

Methods:

We analysed tissue samples from the right and left ventricle (RV and LV) of explanted hearts from 101 patients who underwent an HTx  (67 males, 34 females, mean age 55.6 ± 10.2 years, mean BMI 25.7 ± 4.4). For 21 patients, myocardial samples from a prior LVAD implantation were also available and investigated. These samples were homogenised in a precellys homogeniser, and proteins extracted in 4% sodium deoxycholate, 10ug of protein lysate was subjected to the single pot (SP3) tryptic digestion, and 100ng were analysed in a high-resolution timsToF mass spectrometer scheduled for 20min chromatographic separations per sample operated in a data independent acquisition mode. Raw data were analysed using the neuronal network-based DiaNN algorithm, and statistical analysis of proteomic and clinical data was done with Perseus, InstanClue and SPSS software packages.

Results:

We successfully established a feasible and robust proteomic workflow in sample and data analysis time for human myocardial tissue samples. The number of identified proteins ranged between 2000 and 6000 across all models. Bioinformatic analysis revealed a significantly different proteome between the LV and RV samples, which are now correlated to clinical patient characteristics.

 Conclusions:

In this study, we analysed the myocardial proteome of over 100 heart failure patients with a newly implemented proteomic workflow, showing distinct differences in the proteome of the left and the right ventricle. The fact that we can locally identify differences in the relevant molecular pathways between the ventricles and the correlation to clinical patient history may help better to understand the mechanisms of distinct heart failure etiologies and develop new therapeutic interventions.