Proteomic investigations into hypertension: what's new and how might it affect clinical practice?

Introduction: Hypertension is a multifactorial disease that has, thus far, proven to be a difficult target for pharmacological intervention. The application of proteomic strategies may help to identify new biomarkers for the early diagnosis and prompt treatment of hypertension, in order to control blood pressure and prevent organ damage. Areas covered: Advances in proteomics have led to the discovery of new biomarkers to help track the pathophysiological processes implicated in hypertension. These findings not only help to better understand the nature of the disease, but will also contribute to the clinical needs for a timely diagnosis and more precise treatment. In this review, we provide an overview of new biomarkers identified in hypertension through the application of proteomic techniques, and we also discuss the difficulties and challenges in identifying biomarkers in this clinical setting. We performed a literature search in PubMed with the key words 'hypertension' and 'proteomics', and focused specifically on the most recent literature on the utility of proteomics in hypertension research. Expert opinion: There have been several promising biomarkers of hypertension identified by proteomics, but too few have been introduced to the clinic. Thus, further investigations in larger cohorts are necessary to test the feasibility of this strategy for patients. Also, this emerging field would profit from more collaboration between clinicians and researchers.

Estudio del riesgo cardiovascular en pacientes con bloqueo del sistema renina-angiotensina a través del proteoma de las vesículas extracelulares circulantes / Cardiovascular risk study in patients with renin-angiotensin system blockade by means of the proteone of circulating extracellular vesicles

Introducción: Las vesículas extracelulares (EV) son liberadas al torrente circulatorio por determinados tipos celulares a consecuencia de procesos de transporte, activación o muerte celular. El recuento de EV circulantes de origen plaquetario y endotelial ha demostrado tener un importante papel como biomarcador de riesgo cardiovascular. Por lo tanto, el proteoma de estas EV podría reflejar los procesos celulares subyacentes en pacientes con hipertensión arterial y albuminuria. Material y métodos: El contenido proteico de las EV circulantes se ha analizado mediante cromatografía líquida acoplada a espectrometría de masas. Las EV han sido aisladas mediante un protocolo de ultracentrifugación optimizado para evitar la contaminación de proteínas del plasma. La pureza de la fracción aislada ha sido verificada mediante microscopia electrónica y confocal, y por citometría de flujo. Resultados: En este estudio mostramos un método de gran rendimiento y pureza para obtener extractos proteicos de EV circulantes de pacientes hipertensos con/sin albuminuria para análisis proteómico. Además, aportamos el proteoma de referencia de EV de estos pacientes, compuesto por 2.463 proteínas, y demostramos que las proteínas transportadas por estas vesículas están relacionadas con procesos cruciales involucrados en el riesgo cardiovascular asociado. Conclusión: El proteoma de las EV circulantes constituye una interesante fuente de indicadores para la evaluación de procesos relacionados con el riesgo cardiovascular en pacientes hipertensos con bloqueo del sistema renina-angiotensina

Introduction: Extracellular vesicles (EVs) are released to the bloodstream by certain cell types due to transport, activation and cell death processes. Blood count of EVs from platelet and endothelial origin has been proved to be a cardiovascular risk biomarker. Thus, EVs proteome might reflect the underlying cellular processes in hypertensive patients with albuminuria. Material and methods: Protein content of circulating EVs was analyzed by liquid chromatography coupled to mass spectrometry. EVs were isolated by an ultracentrifugation protocol optimized in order to avoid contamination by blood plasma proteins. Purity of the isolated fraction was verified by electronic and confocal microscopy, and by flow cytometry. Results: We hereby show a method to isolate circulating EVs from hypertensive patients with/without albuminuria with high yield and purity. Besides, we provide a reference proteome of the EVs of these patients, composed of 2,463 proteins, and prove that the proteins carried by these vesicles are associated with crucial processes involved in the inherent cardiovascular risk. Conclusion: The proteome of circulating EVs is an interesting source of indicators in the evaluation of cardiovascular risk in hypertensive patients with renin-angiotensin system blockage

[Cardiovascular risk study in patients with renin-angiotensin system blockade by means of the proteone of circulating extracellular vesicles]. / Estudio del riesgo cardiovascular en pacientes con bloqueo del sistema renina-angiotensina a través del proteoma de las vesículas extracelulares circulantes.

INTRODUCTION: Extracellular vesicles (EVs) are released to the bloodstream by certain cell types due to transport, activation and cell death processes. Blood count of EVs from platelet and endothelial origin has been proved to be a cardiovascular risk biomarker. Thus, EVs proteome might reflect the underlying cellular processes in hypertensive patients with albuminuria. MATERIAL AND METHODS: Protein content of circulating EVs was analyzed by liquid chromatography coupled to mass spectrometry. EVs were isolated by an ultracentrifugation protocol optimized in order to avoid contamination by blood plasma proteins. Purity of the isolated fraction was verified by electronic and confocal microscopy, and by flow cytometry. RESULTS: We hereby show a method to isolate circulating EVs from hypertensive patients with/without albuminuria with high yield and purity. Besides, we provide a reference proteome of the EVs of these patients, composed of 2,463 proteins, and prove that the proteins carried by these vesicles are associated with crucial processes involved in the inherent cardiovascular risk. CONCLUSION: The proteome of circulating EVs is an interesting source of indicators in the evaluation of cardiovascular risk in hypertensive patients with renin-angiotensin system blockage.

Proteomic characterization of EPCs and CECs "in vivo" from acute coronary syndrome patients and control subjects.

BACKGROUND: Circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) represent two scarce blood populations that are thought to play important roles in tissue vascularization. They have also been proposed as potential markers for more than a dozen pathologies. Moreover, EPCs have arisen as a new therapeutic option for cardiovascular disease. However nowadays there is certain controversy about their roles and a better understanding of EPC biology is required to develop new strategies for forthcoming therapies. METHODS: Flow cytometry analysis was performed on freshly isolated mononuclear cells from control subjects and Acute Coronary Syndrome (ACS) patients. EPCs and CECs for both groups were isolated and quantified. Statistical analyses were performed to test the potential biomarker usefulness of both populations in ACS together with the first "in vivo" proteomic characterizations of these populations. RESULTS: Our results do not show statistical differences in the quantification of CECs and EPCs in control subjects and ACS patients. The proteomic characterization allowed us to identify 673 proteins associated to CECs (389 in controls and 462 in ACS patients), and another 502 proteins in EPCs (350 in controls and 274 in ACS patients). CONCLUSIONS: Our data show the necessity to obtain a more accurate and specific phenotype of CECs and EPCs cells as well as a flow cytometry "golden standard" protocol, before they can be considered useful clinical markers. GENERAL SIGNIFICANCE: The proteomic data suggest a potential effect of ACS in the protein profiles of these cells.