The Maastricht Acquisition Platform for Studying Mechanisms of Cell-Matrix Crosstalk (MAPEX): An Interdisciplinary and Systems Approach towards Understanding Thoracic Aortic Disease

Current management guidelines for ascending thoracic aortic aneurysms (aTAA) recommend intervention once ascending or sinus diameter reaches 5-5.5 cm or shows a growth rate of >0.5 cm/year estimated from echo/CT/MRI. However, many aTAA dissections (aTAAD) occur in vessels with diameters below the surgical intervention threshold of <55 mm. Moreover, during aTAA repair surgeons observe and experience considerable variations in tissue strength, thickness, and stiffness that appear not fully explained by patient risk factors. To improve the understanding of aTAA pathophysiology, we established a multi-disciplinary research infrastructure: The Maastricht acquisition platform for studying mechanisms of tissue-cell crosstalk (MAPEX). The explicit scientific focus of the platform is on the dynamic interactions between vascular smooth muscle cells and extracellular matrix (i.e., cell-matrix crosstalk), which play an essential role in aortic wall mechanical homeostasis. Accordingly, we consider pathophysiological influences of wall shear stress, wall stress, and smooth muscle cell phenotypic diversity and modulation. Co-registrations of hemodynamics and deep phenotyping at the histological and cell biology level are key innovations of our platform and are critical for understanding aneurysm formation and dissection at a fundamental level. The MAPEX platform enables the interpretation of the data in a well-defined clinical context and therefore has real potential for narrowing existing knowledge gaps. A better understanding of aortic mechanical homeostasis and its derangement may ultimately improve diagnostic and prognostic possibilities to identify and treat symptomatic and asymptomatic patients with existing and developing aneurysms.

Does statins promote vascular calcification in chronic kidney disease?

BACKGROUND

In end-stage renal disease (ESRD), coronary artery calcification (CAC) and inflammation contribute to cardiovascular disease (CVD). Statins do not improve survival in patients with ESRD, and their effect on vascular calcification is unclear. We explored associations between CAC, inflammatory biomarkers, statins and mortality in ESRD.

MATERIALS AND METHODS

In 240 patients with ESRD (63% males; median age 56 years) from cohorts including 86 recipients of living donor kidney transplant (LD-Rtx), 96 incident dialysis patients and 58 prevalent peritoneal dialysis patients, associations of CAC score (Agatston Units, AUs), interleukin-6 (IL-6) with high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor (TNF), use of statins and all-cause mortality were analysed. Cardiac CT was repeated in 35 patients after 1·5 years of renal replacement therapy. In vitro, human vascular smooth muscle cells (hVSMCs) were used to measure vitamin K metabolism.

RESULTS

Among 240 patients, 129 (53%) had a CAC score > 100 AUs. Multivariate analysis revealed that independent predictors of 1-SD higher CAC score were age, male gender, diabetes and use of statins. The association between CAC score and mortality remained significant after adjustment for age, gender, diabetes, CVD, use of statins, protein-energy wasting and inflammation. Repeated CAC imaging in 35 patients showed that statin therapy was associated with greater progression of CAC. In vitro synthesis of menaquinone-4 by hVSMCs was significantly impaired by statins.

CONCLUSION

Elevated CAC score is a mortality risk factor in ESRD independent of inflammation. Future studies should resolve if statins promote vascular calcification and inhibition of vitamin K synthesis in the uremic milieu.