Striated muscle-specific serine/threonine-protein kinase beta (SPEGβ) segregates with high- versus low-responsiveness to endurance exercise training

Bi-directional selection for either high- or low-responsiveness to endurance running has created divergent rat phenotypes of high-response trainers (HRT) and low-response trainers (LRT). We conducted proteome profiling of HRT and LRT gastrocnemius of 10 female rats (body weight 279 ± 35 g; n=5 LRT and n=5 HRT) from generation 8 of selection. Differential analysis of soluble proteins from gastrocnemius was conducted using label-free quantitation.Genetic association studies were conducted in 384 Russian international-level athletes (age 23.8 ± 3.4 y; 202 males and 182 females) stratified to endurance or power disciplines. Proteomic analysis encompassed 1,024 proteins, 76 of which exhibited statistically significant (P<0.05, FDR <1 %) differences between HRT and LRT muscle. There was significant enrichment of enzymes involved in glycolysis/ gluconeogenesis in LRT muscle but no enrichment of gene ontology phrases in HRT muscle. Striated muscle-specific serine/threonine-protein kinase beta (SPEGβ) exhibited the greatest difference in abundance and was 2.64-fold greater (P=0.0014) in HRT muscle. Co-immunoprecipitation identified 24 potential binding partners of SPEGβ in HRT muscle. The frequency of the G variant of the rs7564856 polymorphism that increases SPEG gene expression, was significantly greater (32.9 vs 23.8%; OR = 1.6, P = 0.009) in international-level endurance athletes (n=258) compared to power athletes (n=126) and was significantly associated (β = 8.345, P = 0.0048) with a greater proportion of slow-twitch fibres in vastus lateralis of female endurance athletes. Co-immunoprecipitation of SPEGβ in HRT muscle discovered putative interacting proteins that link with previously reported differences in transforming growth factor-β signalling in exercised muscle

Relationship of bone mineral density with disease activity and functional ability in patients with ankylosing spondylitis: a cross-sectional study

In ankylosing spondylitis, inflammatory activity probably plays a key role in the pathophysiology of bone loss. The aim of the study was to investigate the relationship of bone mineral density (BMD) at the lumbar spine and hip region with some measures of disease activity and functional ability in patients with ankylosing spondylitis. In 80 patients with established ankylosing spondylitis, disease activity and functional ability were determined by C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI). Spinal pain and patient global health were assessed using horizontal visual analog scale. BMD was measured by dual-energy X-ray absorptiometry. There was a significant negative correlation of bone density T scores with acute-phase reactants (i.e., patients with lower T scores had higher level of CRP and ESR). That relationship was reflected more reliably at proximal femur sites than at the lumbar spine. There were also significant differences in ESR, BASDAI, BASFI, spinal pain and global health between three groups of patients according to WHO classification of osteoporosis (normal, osteopenic and osteoporotic). Significantly, more patients with osteopenia at the lumbar spine had lower BASDAI index than those with normal BMD (P = 0.030). Our results indicate an association of low BMD with high disease activity in patients with AS. Femoral BMD seems to be more associated with disease activity and functional ability than lumbar spine BMD

Osteoporosis in psoriatic arthritis: is there any?

AIMS: Although considered as a feature of inflammatory rheumatic diseases, there is a lot of controversy around low bone mass in patients with psoriatic arthritis. The aim of this cross-sectional study was to analyze bone mineral density in patients with psoriatic arthritis, as well as to investigate its possible association with some measures of disease activity and functional capacity. ----- SUBJECTS AND METHODS: Sixty-nine patients with established psoriatic arthritis (mean age 56.20 ± 12.23 years) and who have not been treated with specific antiosteoporotic drugs were recruited from the out-patient clinic database. Bone mineral density was measured by dual-energy X-ray absorptiometry at the lumbar spine and at the left hip. Disease activity measures included: duration of morning stiffness, tender and swollen joint count, patient's and physician's global assessment, presence of dactylitis and enthesitis, ESR, CRP and Disease Activity Score 28. Health Assessment Questionnaire was used to assess functional status. ----- RESULTS: According to WHO definition, spinal osteoporosis was found in 7.2% of patients, total hip osteoporosis in 1.4% of patients and femoral neck osteoporosis in 2.9% of patients. There was no significant association of any of the measures of disease activity with BMD at any site. Higher HAQ scores were associated with lower total hip BMD. ----- CONCLUSIONS: In our sample of patients with psoriatic arthritis we did not find increased prevalence of osteoporosis. There was no association of BMD with indices of disease activity, while negative correlation was found between HAQ and total hip BMD