Histochem Cell Biol DOI 10.1007/s00418-007-0372-9 123 ORIGINAL PAPER Expression of glucose transporters GLUT-1, GLUT-3, GLUT-9 and HIF-1 in normal and degenerate human intervertebral disc S. M. Richardson · R. Knowles · J. Tyler · A. Mobasheri · J. A. Hoyland Accepted: 9 December 2007 © Springer-Verlag 2007 Abstract The glucose transporters GLUT-1 and GLUT-3 are targets of the hypoxia-inducible transcription factor HIF-1 and it has been shown that nucleus pulposus (NP) cells in rat intervertebral discs (IVD) express both HIF-1 and GLUT-1. However, there is limited data on the expres- sion of HIF-1 and GLUTs in human IVD. The aim here was to (1) determine whether, like articular chondrocytes, human IVD cells express GLUT-1, 3 and 9 and whether there was any co-expression with HIF-1; and (2) to local- ise expression of the GLUT isoforms in the disc and iden- tify any changes during degeneration. Real-time PCR was used to identify expression of GLUT1, 3, 9 and HIF-1 mRNAs and immunohistochemistry was used to analyse protein expression and localisation of GLUTs in normal and degenerate IVD biopsies. Results conWrmed HIF-1, GLUT1, 3 and 9 mRNA expression in NP and AF and co- expression of each GLUT isoform with HIF-1 in the NP, but not the AF. Immunohistochemistry demonstrated regional diVerences in GLUT expression, with the highest expression being in the NP. GLUT expression also changed as degeneration progressed. This study demonstrates that NP and AF cells have diVerent GLUT expression proWles that suggest regional diVerences in the metabolic nature of the human IVD and that this environment changes during degeneration. Keywords Intervertebral disc · Degeneration · Hypoxia · HIF-1 · GLUT-1 · GLUT-3 · GLUT-9 · Immunohistochemistry · Real-time PCR Introduction Degenerative disorders of the intervertebral disc (IVD) and articular cartilage are generally characterised by disequilib- rium between extracellular matrix repair and degradative processes (Le Maitre et al. 2004; Freemont et al. 2002). Molecular alterations include elevated matrix metallopro- teinase (Goupille et al. 1998; Crean et al. 1997) and aggre- canase activity (Pockert et al. 2006), increased expression of (and sensitivity to) catabolic cytokines (Le Maitre et al. 2005) and disc cell senescence (Le Maitre et al. 2007) and apoptosis (Gruber and Hanley 1998). These changes lead to narrowing of the disc space (Yasuma et al. 1990) and mechanical failure of the disc (Thompson et al. 2000; Iatri- dis et al. 1999). Cell density in the fully developed, healthy IVD is very low (approximately 4,000 mm ¡3 in the NP) (Maroudas et al. 1975) and the poor diVusion of nutrients (i.e. O 2 and glucose) and accumulation of metabolic waste products such as lactate (Ohshima and Urban 1992; Bartels et al. 1998) present disc cells with further environmental challenges because of the absence of microvasculature (Repanti et al. 1998). Normally the cells of the outer annu- lus Wbrosus (OAF) are supplied with nutrients by the blood vessels within the outer surface of the AF, but the cells of the inner annulus Wbrosus (IAF) and nucleus pulposus (NP) S. M. Richardson · R. Knowles · J. Tyler · J. A. Hoyland (&) Tissue Injury and Repair Group, Clinical and Laboratory Sciences, Faculty of Medical and Human Sciences, The University of Manchester, Manchester M13 9PT, UK e-mail: judith.a.hoyland@manchester.ac.uk S. M. Richardson e-mail: s.richardson@manchester.ac.uk A. Mobasheri Division of Veterinary Medicine, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, College Road, Sutton Bonington, Leicestershire LE12 5RD, UK