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Abstract: TH-PO150

Endothelial Cell Dysfunction Promotes Phosphate-Induced Vascular Smooth Muscle Cell Calcification

Session Information

  • CKD-MBD: Targets and Outcomes
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

  • 401 Bone and Mineral Metabolism: Basic

Authors

  • Chen, Wei, Albert Einstein College of Medicine, Bronx, New York, United States
  • Riascos-Bernal, Dario F., Albert Einstein College of Medicine, Bronx, New York, United States
  • Zaslow, Shari J., Albert Einstein College of Medicine, Bronx, New York, United States
  • Ross, Michael J., Albert Einstein College of Medicine, Bronx, New York, United States
  • Mowrey, Wenzhu, Albert Einstein College of Medicine, Bronx, New York, United States
  • Chen, Yabing, The University of Alabama at Birmingham Department of Pathology, Birmingham, Alabama, United States
  • Sibinga, Nicholas, Albert Einstein College of Medicine, Bronx, New York, United States
Background

The study objective was to understand interactions between two major vascular cell types – endothelial cells (ECs) and vascular smooth muscle cells (SMCs) – in the pathogenesis of phosphate-induced vascular calcification. Since vascular calcification greatly resembles bone formation, understanding cellular interactions that are unique to the vasculature may help identify therapies that inhibit vascular calcification without adversely impacting bone health. Here, we tested the hypothesis that high phosphate (P) promotes EC dysfunction, which in turn enhances calcification of SMCs in culture.

Methods

To model distinct aspects of complex in vivo environment, we established an in vitro insert co-culture system of primary human aortic ECs and SMCs. We compared calcification of SMCs co-cultured with and without ECs. Calcification of SMCs was induced by high P media (2 mM calcium, 3 mM P), assessed by Alizarin Red staining, and quantified by calcium content. EC proliferation and viability were measured using a resazurin assay.

Results

After 7 days of incubation, SMCs co-cultured with ECs in regular media (1.6 mM calcium, 0.5 mM P) had minimal calcification (10 ± 8 µg calcium/mg protein). In contrast, SMCs co-cultured with ECs and high P media showed overt calcification. SMC calcium content was significantly greater when co-cultured with ECs (102 ± 18 µg calcium/mg protein) than without ECs (59 ± 17 µg calcium/mg protein, p=0.001; Figure). Compared to regular media, high P decreased EC proliferation (p=0.01), but did not change EC viability (p=0.56), suggesting P-induced EC dysfunction.

Conclusion

Using a physiological model of co-cultured primary human cells, we found that high P induced EC dysfunction, which in turn worsened P-induced SMC calcification. These findings support the significance of cellular interactions in the pathogenesis of vascular calcification. Further studies are needed to elucidate the molecular mechanisms underlying these interactions.

Human aortic ECs (HAECs) ehanced P-induced calcification of human aortic SMCs (HASMCs) in a co-culture system.

Funding

  • NIDDK Support