Effects of secreted factors in culture medium of annulus fibrosus cells on microvascular endothelial cells: Elucidating the possible pathomechanisms of matrix degradation and nerve in-growth in disc degeneration

Hong Joo Moon, T. Yurube, T. P. Lozito, P. Pohl, R. A. Hartman, G. A. Sowa, J. D. Kang, N. V. Vo

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Objective: To test whether the interaction between annulus fibrosus cells (AFCs) and endothelial cells (ECs) disrupts matrix homeostasis and stimulates production of innervation mediators. Methods: Human microvascular ECs were cultured in the conditioned media of AF cell culture derived from degenerated human surgical specimen. Matrix-metalloproteinases (MMPs) and platelet-derived growth factor (PDGF) of ECs of this culture were analyzed by qRT-PCR, Western, and immunofluorescence. Vascular endothelial growth factor (VEGF), Interleukin-8 (IL-8), and nerve growth factor (NGF) in the media of this cell culture were assayed by ELISA. To determine the effects of ECs on AFCs, qRT-PCR was performed to determine mRNA levels of collagen I, II and aggrecan in AFCs cultured in EC conditioned media. Results: Compared to ECs cultured in naïve media, ECs exposed to AFC conditioned media expressed higher mRNA and protein levels of key biomarkers of invasive EC phenotype, MMP-2 (2×), MMP-13 (4×), and PDGF-B (1.5-2×), and NGF (24.9±15.2pg/mL vs 0 in naïve media). Treatment of AF cells with EC culture conditioned media decreased collagen type II expression two fold. Considerable quantities of pro-angiogenic factors IL-8 (396.7±302.0pg/mL) and VEGF (756.2±375.9pg/mL) were also detected in the conditioned media of untreated AF cell culture. Discussion: AFCs from degenerated discs secreted factors which stimulated EC production of factors known to induce matrix degradation, angiogenesis, and innervation. IL-8 and VEGF maybe the secreted factors from AFCs which mediate a pro-angiogenic stimulus often implicated in the development of disc degeneration.

Original languageEnglish
Pages (from-to)344-354
Number of pages11
JournalOsteoarthritis and Cartilage
Volume22
Issue number2
DOIs
Publication statusPublished - 2014 Feb 1

Keywords

  • Angiogenesis
  • Annulus fibrosus
  • Endothelial cells
  • Intervertebral disc degeneration
  • Metalloproteinases
  • Tip cells

ASJC Scopus subject areas

  • Rheumatology
  • Biomedical Engineering
  • Orthopedics and Sports Medicine

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