Using peripheral blood mononuclear cells to determine proteome profiles in human cardiac failure

Peripheral Blood MicroRNA-21 as a Predictive Biomarker for Heart Failure With Preserved Ejection Fraction in Old Hypertensives

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a major health issue with high morbidity and mortality. The epidemiology and the factors that cause HFpEF have not been fully clarified, while accurate predictive biomarkers are lacking. Our aim was to determine whether levels of microRNA-21 (miR-21) in peripheral blood monocytes, which play a critical role in many pathophysiological pathways of hypertensive heart disease, can predict the occurrence of HFpEF in older hypertensives, as well as the associated mortality and morbidity.

METHODS

We enrolled 151 elderly patients >60 years old with essential hypertension but without HF at baseline. miRs expression levels in peripheral blood mononuclear cells had been quantified by real-time reverse transcription polymerase chain reaction.

RESULTS

During a median follow-up of 8.2 years, 56 patients (37%) had an event. Levels of miR-21 in peripheral mononuclear blood cells proved to be significantly associated with the occurrence of HFpEF. More specifically, the median HFpEF-free period was 110 months for those with miR-21 >2.1 and 114 months for those with miR-21 <2.1. In addition, multivariate analysis showed that miR-21 (hazard ratio 11.14), followed by hemoglobin (Hg) (hazard ratio 0.56 for Hg >13.6 g/dl, a 45% risk reduction), were independent and the most significant predictors of HFpEF events.

CONCLUSIONS

miR-21 levels in peripheral blood monocytes are associated with the development of future HFpEF. Our findings may alter the risk models of HFpEF and support the rationale for further research into the modulation of miRs as biomarkers and treatment targets for HFpEF.

Peripheral Blood MicroRNAs as Potential Biomarkers of Myocardial Damage in Acute Viral Myocarditis

Background: microRNAs (miRs) have emerged as important modulators of cardiovascular development and disease. Our aim was to determine whether cardiac-related miRs such as miR-21-5p and miR-1-3p were differentially expressed in acute viral myocarditis and whether any of them was related with the extent of myocardial damage and left ventricular dysfunction. Methods: We enrolled 40 patients with acute viral myocarditis. Blood samples were taken on admission and miRs expression levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Results: miR-21-5p, miR-1-3p were significantly elevated in acute myocarditis. miR-21-5p levels showed a strong correlation with global longitudinal strain (r = 0.71, p < 0.01), while miR-1-3p had significant correlations with troponin I (r = 0.79, p < 0.01). Conclusions: The expression of miR-21-5p and miR-1-3p in peripheral blood is increased in acute viral myocarditis, and this increase is correlated with myocardial damage and indicative of left ventricular systolic dysfunction in these patients.

Unlocking the Value of White Blood Cells for Heart Failure Diagnosis

Cardiovascular disease (CVD) is the single greatest cause of mortality and morbidity worldwide. Inciting 85% of CVD fatalities is heart failure, often resulting in or from a myocardial infarction. Early detection along with pharmacological treatment and lifestyle adaptation can result in better prognosis. Biomarkers are molecular or physiological measures that indicate disease presence, status, and severity. However, not all forms of heart failure are created equal. Current mainstay biomarkers for heart failure, including NT-pro-BNP and ejection fraction, lack sensitivity for many patients. Circulating white blood cells and peripheral blood mononuclear cells (PBMCs) are emerging as surrogate biopsies, reflecting molecular changes in the heart. We discuss the advantages of PBMCs over other sources, as well as limitations and considerations. We urge medical center biobanks to collect, isolate and store circulating white blood cells as a rich source of biomarkers to catalyze the discovery of novel diagnostic tools for heart failure.

Interindividual variation in the proteome of human peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMCs) are main actors in inflammatory processes and linked to many diseases, including rheumatoid arthritis, atherosclerosis, asthma, HIV and cancer. Moreover, they seem an interesting ‘surrogate tissue’ that can be used in biomarker discovery. In order to get a good experimental design for quantitative expression studies, the knowledge of the interindividual variation is an essential part. Therefore, PBMCs were isolated from 24 healthy volunteers (15 males, 9 females, ages 63–86) with no clinical signs of inflammation. The extracted proteins were separated using the two dimensional difference in gel electrophoresis technology (2D-DIGE), and the gel images were processed with the DeCyder 2D software. Protein spots present in at least 22 out of 24 healthy volunteers were selected for further statistical analysis. Determination of the coefficient of variation (CV) of the normalized spot volume values of these proteins, reveals that the total variation of the PBMC proteome varies between 12,99% to 148,45%, with a mean value of 28%. A supplemental look at the causes of technical variation showed that the isolation of PBMCs from whole blood is the factor which influences the experimental variance the most. This isolation should be handled with extra care and an additional washing step would be beneficial. Knowing the extent of variation, we show that at least 10 independent samples per group are needed to obtain statistical powerful data. This study demonstrates the importance of considering variance of a human population for a good experimental design for future protein profiling or biomarker studies.