is the most common arthritic condition. OA causes joint pain, loss of mobility and significantly affects the quality of life for the affected individual. The major burden to patients with arthritis is pain. However, often radiological joint destruction and the extent of pain do not correlate. This causes a dilemma for clinicians in advising timing for joint replacement surgery. In arthritis, concentrations of the neurotransmitter, glutamate is increased within the synovial fluid activating both peripheral pain mechanisms and pathological processes (1). Other pathological/pain related metabolites are also released into synovial fluid, which provides a real time snap shot of the joint pathology. We have tested the hypothesis that ‘The increased levels of pain and disease-related metabolites within human synovial fluids from arthritic joints can be detected and quantified ex vivo using high resolution 1H-NMR.’ OA synovial fluid samples were obtained during arthroscopy or total knee replacements from patients with varying degrees of pain and pathology (cartilage graded 0-4; n=21). Pain perception was determined using the Oxford knee score and samples sub-classified as mild, moderate and severe pain. All samples were analysed using 500 MHz 1H NMR spectroscopy. Chemical shifts were referenced to a known concentration NMR internal standard (TSP), peaks identified by reference to published synovial fluid NMR spectra (2) and peak integrals measured using the Bruker software Topspin 2.0. Results: Using NMR we were able to detect around 26 metabolite-specific peaks in synovial fluid spectra (such as glutamate/glutamine, isoleucine, acetyl glucoproteins, beta-hydroxbutyrate, CH2 lipids, lactate, glucose). Some specific metabolites varied significantly with pain or pathological score. For example, we found significantly more glutamate/glutamine, isoleucine and beta-hydroxybutyrate (p<0.05, T test) in OA samples reporting mild to moderate levels of pain (n=14) compared to severe pain (n=7). Significantly more CH2 lipids (p<0.05, T-test) were also present in samples indicating severe pain compared to mild/moderate pain.Osteoarthritis (OA)
Method
Meniscal tears commonly occur after a traumatic twisting injury to the knee (acute) or can form over time (degenerate). Symptoms include pain, swelling, and ‘locking’ of the knee. These symptoms are also commonly associated with osteoarthritis (OA). In some cases of OA, degenerative meniscal tears can also be present making it difficult to determine the cause of symptoms. Furthermore, acute meniscal lesions may be associated with early stage OA but often no radiological signs are evident. Many metabolites associated with joint disorders are released into the synovial fluid providing a real-time snap shot of joint pathology. The ability to examine concentrations of specific metabolites within synovial fluid could provide invaluable clinical information about the cause and stage of joint pathology. We have tested the hypothesis that ‘high resolution 1H-NMR can discriminate between osteoarthritic and meniscal tear-related metabolites within human synovial fluids and aid in clinical diagnosis.’ Synovial fluid samples have been obtained during arthroscopy or knee replacement from patients with varying degrees of joint pathology (cartilage graded 0-4; meniscal tears classified as acute or degenerative). Samples were also taken from patients undergoing Anterior Cruciate Ligament (ACL) reconstruction with no additional pathology. Samples were analysed using 500 MHz 1H NMR spectroscopy. Chemical shifts were referenced to known concentration NMR internal standard (TSP), peaks identified by reference to published synovial fluid NMR spectra (1) and peak integrals measured using the Bruker software Topspin 2.0. Spectroscopy revealed a number of differences in metabolites between OA, meniscal tear and ACL pathologies. These included significantly increased concentrations of glutamate, n-acetyl glycoprotein and β-hydroxybutyrate in OA (n=10) and acute meniscal tears (n=6) compared to ACL samples (p<0.05, T-test, n=6). Specific metabolites were also able to discriminate between OA with no meniscal tear and OA with meniscal tear synovial fluids. For example, concentrations of n-acetyl glycoproteins, glutamate and CH3 lipids were significantly increased in OA without tears (n=10) compared to OA plus meniscal tears (n=12); conversely ceramide concentrations were significantly increased in OA plus tears compared to OA only samples (p<0.05, T-test).Method
Results
