Inflammatory mediators in intervertebral disk degeneration and discogenic pain.
Although degeneration of the intervertebral disk has historically been described as a misbalance between anabolic and catabolic factors, the role of inflammatory mediators has long been neglected. However, past research clearly indicates that inflammatory mediators such as interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α are expressed at higher levels in "diseased" intervertebral disks. Both disk cells as well as invading macrophages can be the source of the detected cytokines. Importantly, occurrence of inflammatory mediators in the disk can worsen the progress of degeneration by inducing the expression of matrix degrading enzymes as well as by inhibiting extracellular matrix synthesis. In addition, inflammatory mediators play a crucial role in pain development during intervertebral disk herniation (i.e., sciatica) and disk degeneration (i.e., discogenic pain). This review provides information on the most relevant inflammatory mediators during different types of disk diseases and explains how these factors can induce disk degeneration and the development of discogenic and sciatic/radiculopathic pain.
Institute for Biomechanics, D-HEST, ETH Zurich, Zurich, Switzerland ; Competence Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland ; AOSpine Research Network, Duebendorf, Switzerland ; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
Karin
K
Wuertz
Competence Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland ; Orthopeadic Research Laboratory, Division of Orthopedic Surgery, McGill University, Montreal, Canada.
Lisbet
L
Haglund
cytokines; degenerative disk disease; discogenic pain; inflammatory mediators; innervation; intervertebral disk degeneration