Abstract 17139: Vascular Smooth Muscle Cells Retain Cell Physiological Abnormalities as a Function of Underlying Type-2 Diabetes.
Rationale: Few methods enable molecular and cellular studies of human vascular aging or type-2 diabetes (T2D).
Objective: To characterize functional responses of human vascular smooth muscle cells (VSMC) differentiated from progenitors found in skin.
Methods and Results: Small biopsies (~1 cm2) 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/g: 0.22±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 Ca2+ concentrations (AU: 1,968±160, N=7 vs. 1,386±170, N=13, P<0.05), a trend towards greater Ca2+ cycling responses to phenylephrine (AUC: 171,545±10,094, N=7 vs. 128,034±14,214, N=13, P=0.06), a reduced frequency of Ca2+ cycling (events ms-1 cell-1: 0.010±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 nM: 72.3±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 (pixel2: 21.9±3.6, N=4 vs. 67.0±10.3, N=4, P<0.05), resembling the impaired wound closure known to occur in T2D.
Conclusion: Skin 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.
Author Disclosures: S.K. Steinbach: None. T. Yau: None. M. Ouzounian: None. H. Abdel-Qadir: None. A. Leligdowicz: None. M. Chandy: None. T. Waddell: None. M. Husain: None.
- © 2016 by American Heart Association, Inc.