Osteoarthritis severity is associated with increased articularis genu muscle pain receptor expression
Location
Medical Education Building, LSUHSC-NO
Presentation Date
10-10-2019 10:00 AM
End Date
10-10-2019 12:00 PM
Description
Osteoarthritis (OA) is a common chronic health condition causing pain and reduced joint motion. The knee is commonly affected by OA, and knee OA has been shown to induce muscle atrophy. The articularis genu muscle is a small muscle that is part of the quadriceps muscle complex and functions to pull the suprapatellar bursa proximally during extension. Quadricep muscle weakness has been associated with osteoarthritis. The aim of the current study is to identify the relationship between OA severity and measures of muscle atrophy and pain receptor expression in the articularis genu muscle of OA patients. Samples of articularis genu muscles collected from 26 female patients at the time of knee replacement surgery were used. Patients had an average age of 70 ± 6 years and an average BMI of 33.4 ± 4.8 kg/m². OA score and Knee Osteoarthritis Outcome Scores (KOOS) were obtained from the patients as measures of OA severity. Total RNA was extracted from the skeletal muscle, and cDNA was synthesized. Specific primers were used to target genes of interest including: muscle ring finger-1 (MuRF1) and atrogin-1 (ubiquitin ligases), transforming growth factor-1 (TGFß1) (fibrosis indicator), transient receptor potential cation channel V1 (TRPV1) (pain receptor), and histone deacetylase 4 (HDAC4). Quantitative PCR (qPCR) was used to determine absolute copy number of genes normalized to RPS13 in each muscle sample. Muscle fiber size was also determined by measuring H&E stained sections on Image J. TRPV1 expression positively correlated with OA score (R²=0.20, p<0.05) and negatively correlated with KOOS Quality of Life (R²=0.17, p<0.05). TRPV1 positively correlated with MuRF1 (R²=0.50, p<0.0001), Atrogin-1 (R²=0.53, p<0.0001), and TGFß1 (R²=0.61, p<0.0001). TRPV1 expression also correlated with HDAC4 expression (R²=0.90, p<0.0001), which has been shown to be required for TRPV1 expression. Measures of muscle atrophy and fibrosis did not significantly correlate with measures of OA severity. In conclusion, muscle pain receptor TRPV1 expression positively correlates with measures of osteoarthritis severity and is positively associated with expression of muscle atrophy and fibrotic markers in osteoarthritic patients. Future work will look at TRPV1 expression in peripheral blood mononuclear cells (PBMCs) at surgery and 3 months post-surgery along with KOOS measures 3 months post-surgery to see if TPRV1 can be used as a biomarker for predicting surgery outcomes.
Recommended Citation
Bourgeois, Brianna L., "Osteoarthritis severity is associated with increased articularis genu muscle pain receptor
expression" (2019). Medical Student Research Poster Symposium. 3.
https://digitalscholar.lsuhsc.edu/sommrd/2019/posters/3
Osteoarthritis severity is associated with increased articularis genu muscle pain receptor expression
Medical Education Building, LSUHSC-NO
Osteoarthritis (OA) is a common chronic health condition causing pain and reduced joint motion. The knee is commonly affected by OA, and knee OA has been shown to induce muscle atrophy. The articularis genu muscle is a small muscle that is part of the quadriceps muscle complex and functions to pull the suprapatellar bursa proximally during extension. Quadricep muscle weakness has been associated with osteoarthritis. The aim of the current study is to identify the relationship between OA severity and measures of muscle atrophy and pain receptor expression in the articularis genu muscle of OA patients. Samples of articularis genu muscles collected from 26 female patients at the time of knee replacement surgery were used. Patients had an average age of 70 ± 6 years and an average BMI of 33.4 ± 4.8 kg/m². OA score and Knee Osteoarthritis Outcome Scores (KOOS) were obtained from the patients as measures of OA severity. Total RNA was extracted from the skeletal muscle, and cDNA was synthesized. Specific primers were used to target genes of interest including: muscle ring finger-1 (MuRF1) and atrogin-1 (ubiquitin ligases), transforming growth factor-1 (TGFß1) (fibrosis indicator), transient receptor potential cation channel V1 (TRPV1) (pain receptor), and histone deacetylase 4 (HDAC4). Quantitative PCR (qPCR) was used to determine absolute copy number of genes normalized to RPS13 in each muscle sample. Muscle fiber size was also determined by measuring H&E stained sections on Image J. TRPV1 expression positively correlated with OA score (R²=0.20, p<0.05) and negatively correlated with KOOS Quality of Life (R²=0.17, p<0.05). TRPV1 positively correlated with MuRF1 (R²=0.50, p<0.0001), Atrogin-1 (R²=0.53, p<0.0001), and TGFß1 (R²=0.61, p<0.0001). TRPV1 expression also correlated with HDAC4 expression (R²=0.90, p<0.0001), which has been shown to be required for TRPV1 expression. Measures of muscle atrophy and fibrosis did not significantly correlate with measures of OA severity. In conclusion, muscle pain receptor TRPV1 expression positively correlates with measures of osteoarthritis severity and is positively associated with expression of muscle atrophy and fibrotic markers in osteoarthritic patients. Future work will look at TRPV1 expression in peripheral blood mononuclear cells (PBMCs) at surgery and 3 months post-surgery along with KOOS measures 3 months post-surgery to see if TPRV1 can be used as a biomarker for predicting surgery outcomes.
Comments
Mentor: Liz Simon, MVSc., PhD (Department of Physiology)