Diagnostic performance of mid-regional pro-adrenomedullin as an analyte for the exclusion of left ventricular dysfunction

Mid-Regional Proadrenomedullin as a New Biomarker of Kidney and Cardiovascular Diseases-Is It the Future?

The increasing prevalence of cardiovascular disease and concomitant chronic kidney disease among the aging populations is responsible for considerable growth of mortality. Additionally, frequent, prolonged hospitalizations and long-term treatment generates progressive decline in bodily functions as well as substantial public health and economic burden. Accessibility to easy, non-invasive prognostic markers able to detect patients at risk of cardiovascular events may improve effective therapy and mitigate disease progression. Moreover, an early diagnosis allows time for implementation of prophylactic and educational programs that may result in decreased morbidity, improved quality of life and reduced public health expenditure. One of the promising candidates for a novel cardiovascular biomarker is mid-regional proadrenomedullin, a derivative of adrenomedullin. Adrenomedullin is a peptide hormone known for its vasodilatory, antioxidant, antiapoptotic and antifibrotic effects. A remarkable advantage of mid-regional proadrenomedullin is its longer half-life which is a prerequisite for plasma measurements. These review aims to discuss the importance of mid-regional proadrenomedullin with reference to its usefulness as a biomarker of increased cardiovascular risk and kidney disease progression.

Inflammation biomarkers and mortality prediction in patients with type 2 diabetes (ZODIAC-27)

BACKGROUND

C-reactive protein (CRP), procalcitonin (PCT) and pro-adrenomedullin (MR-proADM) are inflammation markers associated with long-term mortality risk. We compared the associations and predictive capacities of CRP, PCT and MR-proADM with cardiovascular and all-cause mortality in patients with type 2 diabetes.

METHODS

This study included primary care treated patients with type 2 diabetes participating in the ZODIAC cohort study. A total of 1005 out of 1688 patients (60%) had complete baseline variables. Baseline CRP, PCT and MR-proADM were assessed in relation to cardiovascular and all-cause mortality with Cox proportional hazard analyses. Hazard Ratios (HR) were adjusted for age, gender, BMI, smoking, systolic blood pressure, cholesterol-HDL ratio, duration of diabetes, HbA1c, history of cardiovascular diseases, albumin-creatinine ratio and creatinine. Risk prediction capabilities were assessed with Harrell's C statistics and proportion of explained variance (R(2)).

RESULTS

After a median follow-up of 11 years, 472 (47%) of 1005 patients had died. The likelihood ratio test showed that CRP and MR-proADM significantly improved prediction in cardiovascular mortality [HRs 1.20 (95%CI 1.09-1.33) and 1.56 (95%CI 1.06-2.30)] and in all-cause mortality [HRs 1.10 (95%CI: 1.03-1.18) and 1.31 (95%CI 1.02-1.69)]. Harrell's C values and R(2) measures showed slightly improved discrimination for cardiovascular mortality in patients without macrovascular disease (C: 0.80 to 0.81; R(2): 0.50 to 0.52) and MR-proADM (C: 0.80 to 0.82; R(2): 0.50 to 0.52).

CONCLUSIONS

CRP and MR-proADM, but not PCT, were independently associated with cardiovascular and all-cause mortality. In patients without macrovascular diseases, CRP and MR-proADM slightly improved discrimination, in absolute sense, of patients at risk for cardiovascular mortality.

Plasma levels of intermedin (adrenomedullin-2) in healthy human volunteers and patients with heart failure

Intermedin/adrenomedullin-2 (IMD) is a member of the adrenomedullin/CGRP peptide family. Less is known about the distribution of IMD than for other family members within the mammalian cardiovascular system, particularly in humans. The aim was to evaluate plasma IMD levels in healthy subjects and patients with chronic heart failure. IMD and its precursor fragments, preproIMD(25-56) and preproIMD(57-92), were measured by radioimmunoassay in 75 healthy subjects and levels of IMD were also compared to those of adrenomedullin (AM) and mid-region proadrenomedullin(45-92) (MRproAM(45-92)) in 19 patients with systolic heart failure (LVEF<45%). In healthy subjects, plasma levels (mean+SE) of IMD (6.3+0.6 pg ml(-1)) were lower than, but correlated with those of AM (25.8+1.8 pg ml(-1); r=0.49, p<0.001). Plasma preproIMD(25-56) (39.6+3.1 pg ml(-1)), preproIMD(57-92) (25.9+3.8 pg ml(-1)) and MRproAM(45-92) (200.2+6.7 pg ml(-1)) were greater than their respective bioactive peptides. IMD levels correlated positively with BMI but not age, and were elevated in heart failure (9.8+1.3 pg ml(-1), p<0.05), similarly to MRproAM(45-92) (329.5+41.9 pg ml(-1), p<0.001) and AM (56.8+10.9 pg ml(-1), p<0.01). IMD levels were greater in heart failure patients with concomitant renal impairment (11.3+1.8 pg ml(-1)) than those without (6.5+1.0 pg ml(-1); p<0.05). IMD and AM were greater in patients receiving submaximal compared with maximal heart failure drug therapy and were decreased after 6 months of cardiac resynchronization therapy. In conclusion, IMD is present in the plasma of healthy subjects less abundantly than AM, but is similarly correlated weakly with BMI. IMD levels are elevated in heart failure, especially with concomitant renal impairment, and tend to be reduced by high intensity drug or pacing therapy.

Midregional fragment of proadrenomedullin, new-onset albuminuria, and cardiovascular and all-cause mortality in patients with type 2 diabetes (ZODIAC-30)

OBJECTIVE

The midregional fragment of proadrenomedullin (MR-proADM) is a marker of endothelial dysfunction and has been associated with a variety of diseases. Our aim was to investigate whether MR-proADM is associated with new-onset albuminuria and cardiovascular (CV) and all-cause mortality in patients with type 2 diabetes treated in primary care.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes participating in the observational Zwolle Outpatient Diabetes Project Integrating Available Care (ZODIAC) study were included. Cox regression analyses were used to assess the relation of baseline MR-proADM with new-onset albuminuria and CV and all-cause mortality. Risk prediction capabilities of MR-proADM for new-onset albuminuria and CV and all-cause mortality were assessed with Harrell's C and the integrated discrimination improvement.

RESULTS

In 1,243 patients (mean age 67 [±12] years), the median follow-up was 5.6 years (interquartile range 3.1-10.1); 388 (31%) patients died, with 168 (12%) CV deaths. Log2 MR-proADM was associated with CV (hazard ratio 1.96 [95% CI 1.27-3.01]) and all-cause mortality (1.78 [1.34-2.36]) after adjusting for age, sex, BMI, smoking, systolic blood pressure, cholesterol-to-HDL ratio, duration of diabetes, HbA1c, ACE inhibitor/angiotensin receptor blocker, history of CV diseases, log serum creatinine, and log albumin-to-creatinine ratio. MR-proADM slightly improved mortality risk prediction. The age- and sex-adjusted, but not multivariate-adjusted, MR-proADM levels were associated with new-onset albuminuria.

CONCLUSIONS

MR-proADM was associated with CV and all-cause mortality in patients with type 2 diabetes after a median follow-up of 5.6 years. There was no independent relationship with new-onset albuminuria. In the availability of an extensive set of risk factors, there was little added effect of MR-proADM in risk prediction of CV and all-cause mortality.

Association of MR-proadrenomedullin with cardiovascular risk factors and subclinical cardiovascular disease

AIMS AND BACKGROUND

Midregional proadrenomedullin (MR-proADM) is a protein, which exerts various effects on the cardiovascular system. Recent studies underscored its prognostic implications in patients with acute dyspnea and cardiovascular diseases. Therefore, we aimed to determine the distribution of MR-proADM in the general population and to reveal potential associations of MR-proADM with cardiovascular risk factors and measures of subclinical cardiovascular disease.

METHODS AND RESULTS

MR-proADM plasma concentrations were determined in individuals of the population-based cohort of the Gutenberg Health Study (N = 5000) using a commercially available fluoroimmunoassay. Individuals were enrolled between April 2007 and October 2008. Subclinical cardiovascular disease was assessed using echocardiographic and functional measures of myocardial and vascular function. The mean age of the study population was 55.5 ± 10.9 years. In the overall population we determined a median MR-proADM plasma concentration of 0.44 nmol/L in men and women. MR-proADM concentrations were elevated in individuals with hypertension, diabetes, dyslipidemia, known cardiovascular disease, heart failure, peripheral artery disease, atrial fibrillation, and history of myocardial infarction and stroke. In men, we observed a positive association of MR-proADM with reduced ejection fraction, intraventricular septal diameter, wall thickness, and echocardiographic measures of diastolic dysfunction.

CONCLUSIONS

In this study, we present age-dependent reference values for MR-proADM in a representative population sample. Elevated MR-proADM plasma concentrations were strongly associated with classical cardiovascular risk factors and manifest cardiovascular diseases. Furthermore, we revealed a gender-specific association with echocardiographic measures of hypertension. MR-proADM seems to be a promising prognostic biomarker for subclinical and manifest cardiovascular disease.

Midregional pro-atrial natriuretic peptide: a novel marker of myocardial fibrosis in patients with hypertrophic cardiomyopathy

We aimed to determine the diagnostic performance of biomarkers in predicting myocardial fibrosis assessed by late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) in patients with hypertrophic cardiomyopathy (HCM). LGE CMR was performed in 40 consecutive patients with HCM. Left and right ventricular parameters, as well as the extent of LGE were determined and correlated to the plasma levels of midregional pro-atrial natriuretic peptide (MR-proANP), midregional pro-adrenomedullin (MR-proADM), carboxy-terminal pro-endothelin-1 (CT-proET-1), carboxy-terminal pro-vasopressin (CT-proAVP), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1) and interleukin-8 (IL-8). Myocardial fibrosis was assumed positive, if CMR indicated LGE. LGE was present in 26 of 40 patients with HCM (65%) with variable extent (mean: 14%, range: 1.3-42%). The extent of LGE was positively associated with MR-proANP (r = 0.4; P = 0.01). No correlations were found between LGE and MR-proADM (r = 0.1; P = 0.5), CT-proET-1 (r = 0.07; P = 0.66), CT-proAVP (r = 0.16; P = 0.3), MMP-9 (r = 0.01; P = 0.9), TIMP-1 (r = 0.02; P = 0.85), and IL-8 (r = 0.02; P = 0.89). After adjustment for confounding factors, MR-proANP was the only independent predictor associated with the presence of LGE (P = 0.007) in multivariate analysis. The area under the ROC curve (AUC) indicated good predictive performance (AUC = 0.882) of MR-proANP with respect to LGE. The odds ratio was 1.268 (95% confidence interval 1.066-1.508). The sensitivity of MR-proANP at a cut-off value of 207 pmol/L was 69%, the specificity 94%, the positive predictive value 90% and the negative predictive value 80%. The results imply that MR-proANP serves as a novel marker of myocardial fibrosis assessed by LGE CMR in patients with HCM.

Novel biomarkers in heart failure: an overview

Heart failure is a complex systemic syndrome resulting from significant impairment of cardiac function. A vast array of biological pathways is now known to be involved in heart failure, including deleterious pathways promoting its development and progression, as well as compensatory cardioprotective pathways. Some of the components of these pathways are now recognized as biomarkers of this condition, and can aid diagnosis, prognostication and guide management. As the understanding of the pathophysiology of heart failure progresses, further candidate biomarkers are being identified. This article reviews the literature regarding the more recently identified biomarkers and outlines areas requiring further study.