CRP is an acute-phase protein that is used as a biomarker to follow severity and progression in infectious and inflammatory diseases. Its pathophysiological mechanisms of action are still poorly defined. CRP in its pentameric form exhibits weak anti-inflammatory activity. The monomeric isoform (mCRP) exerts potent proinflammatory properties in chondrocytes, endothelial cells, and leucocytes. No data exist regarding mCRP effects in human intervertebral disc (IVD) cells. This work aimed to verify the pathophysiological relevance of mCRP in the aetiology and/or progression of IVD degeneration. We investigated the effects of mCRP and the signalling pathways that are involved in cultured human primary annulus fibrosus (AF) cells and in the human nucleus pulposus (NP) immortalized cell line HNPSV-1. We determined messenger RNA (mRNA) and protein levels of relevant factors involved in inflammatory responses, by quantitative real-time polymerase chain reaction (RT-qPCR) and western blot. We also studied the presence of mCRP in human AF and NP tissues by immunohistochemistry.Aims
Methods
Intervertebral disc (IVD) degeneration is a prominent cause of low back pain. IVD cells expressing angiopoietin-1 receptor Tie2 represent a progenitor cell population which decreases with progression of IVD degeneration. Homing of mesenchymal stem cells (MSCs) is a physiological mechanism aiming to enhance the regenerative capacity of the IVD. The purpose of this study was to assess the effect of MSC homing on the Tie2 positive IVD progenitor cell population, the IVD cell viability, and the proliferative phenotype of the IVD cells. Human MSCs were isolated from bone marrow aspirates and labelled with fluorescent dye. Whole IVDs with endplates were harvested from bovine tails; MSCs were placed on the endplates. Human traumatic, degenerative and healthy IVD tissues were obtained from patients and organ donors. MSCs were added onto tissue samples. After 5 days, IVD cells were isolated. Percentages of Tie2 positive, DAPI positive (dead) and Ki-67 positive (proliferative) IVD cells were determined. MSC homing or co-culture significantly increased the proportion of Tie2 positive progenitor IVD cells in bovine and 7/10 human IVDs, decreased the fraction of dead IVD cells in bovine and 7/10 human IVDs, and induced a proliferative phenotype in bovine and 5/6 human IVDs.Background and Purpose
Methods and Results
