Potentiated adrenomedullin-induced vasorelaxation during hypoxia in organ cultured porcine coronary arteries

Circulating Midregional Proadrenomedullin and Risk of Incident Abdominal Aortic Aneurysm: A Prospective Longitudinal Cohort Study

Prospective clinical plasma biomarker studies in abdominal aortic aneurysm (AAA) pathogenesis have been hampered by the need for very large cohorts and long follow-up time. The main aim of the present study was to evaluate the association of adrenomedullin, a cardiovascular (CV) stress marker, and incident AAA risk. Prospective longitudinal cohort of middle-aged individuals from the CV cohort of the Malmö Diet and Cancer Study (n = 5551; 1991-1994) was assessed. Plasma concentrations of midregional proadrenomedullin (MR-proADM), C-reactive protein (CRP), and conventional risk factors were measured at baseline. Incidence of AAA was studied up to December 31, 2013. Cumulative incidence of AAA was 1.5% (men 2.9%, women 0.5%). Mean age of individuals with incident AAA was 59.7 years at study entry, and AAA was diagnosed on average 14 years later. Adjusting for age, gender, smoking, body mass index, hypertension, diabetes mellitus, and CRP, MR-proADM (hazard ratio: 1.28; 95% confidence interval: 1.01-1.62) was independently associated with incident AAA. The plasma biomarker MR-proADM seems to be a marker of AAA risk, implying that AAA development may be driven by long-standing CV stress on the aortic wall.

Adrenomedullin and tumour microenvironment

Adrenomedullin (AM) is a regulatory peptide whose involvement in tumour progression is becoming more relevant with recent studies. AM is produced and secreted by the tumour cells but also by numerous stromal cells including macrophages, mast cells, endothelial cells, and vascular smooth muscle cells. Most cancer patients present high levels of circulating AM and in some cases these higher levels correlate with a worst prognosis. In some cases it has been shown that the high AM levels return to normal following surgical removal of the tumour, thus indicating the tumour as the source of this excessive production of AM. Expression of this peptide is a good investment for the tumour cell since AM acts as an autocrine/paracrine growth factor, prevents apoptosis-mediated cell death, increases tumour cell motility and metastasis, induces angiogenesis, and blocks immunosurveillance by inhibiting the immune system. In addition, AM expression gets rapidly activated by hypoxia through a HIF-1α mediated mechanism, thus characterizing AM as a major survival factor for tumour cells. Accordingly, a number of studies have shown that inhibition of this peptide or its receptors results in a significant reduction in tumour progression. In conclusion, AM is a great target for drug development and new drugs interfering with this system are being developed.