Aortic stenosis (AS) is the most common form of valve disease. Once symptoms develop, there is an inexorable deterioration with a poor prognosis; currently there are no therapies capable of modifying disease progression, and aortic valve replacement is the only available treatment. Our goal is to study the progression of calcification by matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) and get new insights at molecular level that could help in the understanding of this disease. In this work, we analyzed consecutive slices from aortic valve tissue by MALDI-IMS, to establish the spatial distribution of proteins and peptides directly from the surface of the histological sections. The analysis showed different structures corresponding to regions observed in conventional histology, including large calcification areas and zones rich in collagen and elastic fibers. Peptide extraction from the tissue, followed by liquid chromatography mass spectrometry analysis, provided the identification of collagen VI α-3 and NDRG2 proteins which correlated with the masses obtained by MALDI-IMS and were confirmed by immunohistochemistry. These results highlighted the molecular mechanism implied in AS using MALDI-IMS, a novel technique never used before in this pathology. In addition, we can define specific regions proving a complementary resolution of the molecular histology.

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A lbuminuria is a risk factor strongly associated with cardiovascular and renal complications particularly when diabetes mellitus and hypertension are present. However, in the absence of these 2 processes, albuminuria can be equally relevant as a predictor.1 These facts reflect the enormous relevance of albuminuria to monitor cardiovascular disease, the first cause of death in the general population.2 Different factors promote the development of albuminuria 3 and lead finally to an increased albumin leakage through the glomerular barrier. [4][5][6][7] Renin-angiotensin system (RAS) suppression is considered the therapy of choice to prevent the development of new-onset albuminuria in naïf patients 8,9 and to diminish the amount of excreted albuminuria. 10 The positive effect depends on a reduction in blood pressure, 11 as well as a modification of intraglomerular hemodynamics and permeability.12 Recent studies conducted by our group have shown that despite an apparently adequate RAS suppression, a relevant percentage of hypertensive patients develop de novo albuminuria pointing to a progression of cardiovascular disease probably facilitated by an inappropriate therapeutic response to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. 13Moreover, we have also found an increased systemic oxidative damage in hypertensive patients who develop albuminuria under chronic RAS suppression suggesting that oxidative stress is one of the mechanisms underlying the development of albuminuria 14 in this situation. These considerations highlight the need to continue searching for potential mechanisms and indicators of the development and progression of albuminuria in hypertensive patients under RAS suppression, considering that it will contribute Abstract-Albuminuria is a risk factor strongly associated with cardiovascular disease, the first cause of death in the general population. It is well established that renin-angiotensin system suppressors prevent the development of new-onset albuminuria in naïf hypertensive patients and diminish its excretion, but we cannot forget the percentage of hypertensive patients who develop de novo albuminuria. Here, we applied multiple proteomic strategy with the purpose to elucidate specific molecular pathways involved in the pathogenesis and provide predictors and chronic organ damage indicators. Briefly, 1143 patients were followed up for a minimum period of 3 years. One hundred and twenty-nine hypertensive patients chronically renin-angiotensin system suppressed were recruited, classified in 3 different groups depending on their albuminuria levels (normoalbuminuria, de novo albuminuria, and sustained albuminuria), and investigated by multiple proteomic strategies. Our strategy allowed us to perform one of the deepest plasma proteomic analysis to date, which has shown 2 proteomic signatures: (1) with predictive value of de novo albuminuria and (2) sustained albuminuria indicator proteins. These proteins are involved in inflammation, immune as well as in the proteasome...