Global plasma protein profiling reveals DCM characteristic protein signatures.

To identify potential biomarkers supporting better phenotyping and to improve understanding of the pathophysiology of dilated cardiomyopathy (DCM), this study comparatively analyzed plasma protein profiles of DCM patients and individuals with low normal and normal left ventricular ejection fraction (LVEF) by mass spectrometry. After plasma depletion using a MARS Hu-6 column, global proteome profiling was performed using a LTQ-Orbitrap Velos mass spectrometer. To compare and confirm results, two different discovery sets of samples were investigated. Differentially abundant proteins are involved in lipid metabolism, coagulation, and acute phase response. Serum paraoxonase 1 (PON1), cystatin C, lysozyme C, apolipoprotein A-II, and apolipoprotein M were validated by targeted protein analysis in a third independent patient cohort. Additionally, PON1 levels were also determined by an ELISA. These data highlight PON1 as a potential marker for differentiating DCM patients not only from patients with normal LVEF, but also from heart failure patients with preserved ejection fraction. The results highlight lipid metabolism and inflammation as the major pathways being altered in DCM patients in comparison to patients presenting with suspicious myocarditis to the hospital. SIGNIFICANCE: Several studies focused on the identification of heart failure (HF) associated protein signatures in blood plasma, but only few that are largely based on only small sample series considered specific HF pathologies. Therefore, we performed a comparative global blood plasma protein profiling of a larger sample of individuals with reduced left ventricular ejection fraction (LVEF) classified as dilated cardiomyopathy patients and individuals with normal LVEF but presenting with suspicious myocarditis. DCM patients displayed altered levels of proteins involved in lipid metabolism, coagulation, and acute phase response. The most reliable candidates, such as serum paraoxonase 1 (PON1), cystatin C, lysozyme C, apolipoprotein A-II, and apolipoprotein M were validated by targeted protein analysis in an independent patient cohort. PON1 levels were also determined by an ELISA. These data highlight PON1 as a potential marker for differentiating DCM patients not only from patients with normal LVEF, but also from heart failure patients with preserved ejection fraction.

In-depth proteomic analysis of the human cerumen-a potential novel diagnostically relevant biofluid.

Human cerumen, also called earwax, is a substance secreted by various glands in the outer ear canal. Although the variation of texture and color during otorhinolaryngological diseases is a generally known phenomenon, cerumen as biofluid remains relatively unexplored. However, there is an emerging interest for protein biomarkers which are easily accessible and predictive for diagnostics and therapy outcome. Here we provide a thorough investigation of human cerumen applying two different prefractionation techniques: i) 1D-PAGE prefractionation with subsequent LC-MS/MS, and ii) online SCX-fractionation coupled to LC-MS/MS. Additionally, individual variation was addressed by shotgun LC-MS/MS of specimens from 5 subjects. In total, we identified 11,562 distinct peptides representing 2013 proteins in human cerumen. The in-depth characterization revealed a high complexity of cerumen comparable with other human biofluids such as urine, plasma, or saliva. A probiotic or antibiotic character of cerumen has previously been discussed. In this study we provide further evidence for the important role of cerumen as an antimicrobial barrier and in local immune response, e.g. by assessing high amounts of zinc-alpha-2-glycoprotein. PRACTICAL IMPLICATIONS: Cerumen analysis might have promising potential as diagnostic body fluid for biomarker characterization and disease specific objectives. Disease-associated or infection-specific changes may support diagnostics in otorhinolaryngology and may lead to a better understanding of human cerumen's function in immune response. An easy-to-handle and standardized sample collection and preparation of cerumen can further improve individualized medicine strategies.