Abstract 17139: Vascular Smooth Muscle Cells Retain Cell Physiological Abnormalities as a Function of Underlying Type-2 Diabetes

• Published in: Circulation (New York, N.Y.) Vol. 134; no. Suppl_1 Suppl 1; p. A17139
• Main Authors: Steinbach, Sarah K, Yau, Terrance, Ouzounian, Maral, Abdel-Qadir, Husam, Leligdowicz, Aleksandra, Chandy, Mark, Waddell, Thomas, Husain, Mansoor
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 11-11-2016
• ISSN: 0009-7322; 1524-4539

RationaleFew methods enable molecular and cellular studies of human vascular aging or type-2 diabetes (T2D).ObjectiveTo characterize functional responses of human vascular smooth muscle cells (VSMC) differentiated from progenitors found in skin.Methods and ResultsSmall biopsies (~1 cm) taken from the edges of leg or chest incisions of subjects (N=123; males 72%; mean age=63±12 years) undergoing cardiothoracic surgery were used to isolate skin cells and quantify the number of skin-derived precursors (SKPs) that can be cultured. Multivariate analysis revealed that the numbers of cells isolated from skin biopsies (normalized to skin weight) were reduced as a function of age, dyslipidemia and coronary artery disease (CAD). Although SKPs could be subsequently cultured from these biopsies and differentiated into VSMCs at high efficiency (>80% yield), the numbers of SKPs isolated from subjects with T2D were ~50% lower than those without T2D (cells/g0.22±0.04, N=46 vs. 0.52±0.07, N=77, P<0.05). Of particular interest, even after a differentiation protocol and prolonged culture in vitro, SKP-derived VSMCs from subjects with T2D manifest higher Fluo-5F-determined baseline cytosolic Ca concentrations (AU1,968±160, N=7 vs. 1,386±170, N=13, P<0.05), a trend towards greater Ca cycling responses to phenylephrine (AUC171,545±10,094, N=7 vs. 128,034±14,214, N=13, P=0.06), a reduced frequency of Ca cycling (events ms cell0.010±0.005, N=7 vs. 0.027±0.003, N=13, P<0.05), and enhanced sensitivity to phenylephrine in an impedance-based assay (EC50 nM72.3±63.6, N=5 vs. 3,684±3,122, N=9, P<0.05). SKP-derived VSMCs from subjects with T2D also showed impaired scratch wound closure capacity in vitro (pixel21.9±3.6, N=4 vs. 67.0±10.3, N=4, P<0.05), resembling the impaired wound closure known to occur in T2D.ConclusionSkin biopsies from older adults undergoing surgery for a variety of underlying cardiac and thoracic diseases yield sufficient SKPs from which to differentiate VSMCs at high efficiency, which in turn reveal distinct cell physiological signatures as a function of whether their source subjects had T2D. This platform will allow mechanistic studies into the disturbed VSMC biology of T2D.