Racial differences in tumor necrosis factor-α-induced endothelial microparticles and interleukin-6 production

Vasc Health Risk Manag. 2011;7:541-50. doi: 10.2147/VHRM.S22930. Epub 2011 Aug 26.

Abstract

African Americans (AA) tend to have heightened systemic inflammation and endothelial dysfunction. Endothelial microparticles (EMP) are released from activated/apoptotic endothelial cells (EC) when stimulated by inflammation. The purpose of our study was to assess EMP responses to inflammatory cytokine (TNF-α) and antioxidant (superoxide dismutase, SOD) conditions in human umbilical vein ECs (HUVECs) obtained from AA and Caucasians. EMPs were measured under four conditions: control (basal), TNF-α, SOD, and TNF-α + SOD. Culture supernatant was collected for EMP analysis by flow cytometry and IL-6 assay by ELISA. IL-6 protein expression was assessed by Western blot. AA HUVECs had greater EMP levels under the TNF-α condition compared to the Caucasian HUVECs (6.8 ± 1.1 vs 4.7% ± 0.4%, P = 0.04). The EMP level increased by 89% from basal levels in the AA HUVECs under the TNF-α condition (P = 0.01) compared to an 8% increase in the Caucasian HUVECs (P = 0.70). Compared to the EMP level under the TNF-α condition, the EMP level in the AA HUVECs was lower under the SOD only condition (2.9% ± 0.3%, P = 0.005) and under the TNF-α + SOD condition (2.1% ± 0.4%, P = 0.001). Basal IL-6 concentrations were 56.1 ± 8.8 pg/mL/μg in the AA and 30.9 ± 14.9 pg/mL/μg in the Caucasian HUVECs (P = 0.17), while basal IL-6 protein expression was significantly greater (P < 0.05) in the AA HUVECs. These preliminary observational results suggest that AA HUVECs may be more susceptible to the injurious effects of the proinflammatory cytokine, TNF-α.

Keywords: African Americans; endothelial microparticles; endothelium; inflammation.

Publication types

  • Comparative Study
  • Video-Audio Media

MeSH terms

  • African Americans*
  • Blotting, Western
  • Cell Shape
  • Cell-Derived Microparticles / immunology*
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay
  • European Continental Ancestry Group*
  • Flow Cytometry
  • Human Umbilical Vein Endothelial Cells / immunology*
  • Humans
  • Inflammation Mediators / metabolism*
  • Interleukin-6 / metabolism*
  • Philadelphia / epidemiology
  • Recombinant Proteins / metabolism
  • Superoxide Dismutase / metabolism
  • Tumor Necrosis Factor-alpha / metabolism*

Substances

  • IL6 protein, human
  • Inflammation Mediators
  • Interleukin-6
  • Recombinant Proteins
  • Tumor Necrosis Factor-alpha
  • Superoxide Dismutase