Intramuscular fatty infiltration and its correlation with muscle composition and function in hip osteoarthritis.

Background: Hip osteoarthritis patients display higher levels of fatty infiltration (FI) in the gluteus minimus (GM) compared to other hip muscles. We investigated specific histological factors such as fiber type composition and collagen deposition, and functional outcomes like muscle strength and activation associated with FI in these patients.

Methods: In twelve men (67 ± 6 y) undergoing total hip replacement (THR), hip and knee muscle strength and activation (electromyography, EMG) were assessed bilaterally.

GLUD1 determines murine muscle stem cell fate by controlling mitochondrial glutamate levels.

Muscle stem cells (MuSCs) enable muscle growth and regeneration after exercise or injury, but how metabolism controls their regenerative potential is poorly understood. We describe that primary metabolic changes can determine murine MuSC fate decisions. We found that glutamine anaplerosis into the tricarboxylic acid (TCA) cycle decreases during MuSC differentiation and coincides with decreased expression of the mitochondrial glutamate deaminase GLUD1.

MME fibro-adipogenic progenitors are the dominant adipogenic population during fatty infiltration in human skeletal muscle.

Fatty infiltration, the ectopic deposition of adipose tissue within skeletal muscle, is mediated via the adipogenic differentiation of fibro-adipogenic progenitors (FAPs). We used single-nuclei and single-cell RNA sequencing to characterize FAP heterogeneity in patients with fatty infiltration. We identified an MME FAP subpopulation which, based on ex vivo characterization as well as transplantation experiments, exhibits high adipogenic potential.

Tender to touch-Prevalence and impact of concomitant fibromyalgia and enthesitis in spondyloarthritis: An ancillary analysis of the ASAS PerSpA study.

Objectives: The primary objective was to evaluate the co-existence of fibromyalgia (FM) & enthesitis in individuals with spondyloarthritis (SpA). Secondary objectives were to identify clinical features associated with the presence of FM in enthesitis and analyse sex-specific differences.

Methods: This was an ancillary analysis of the Assessment of SpondyloArthritis International Society Peripheral Involvement in SpA (PerSpA) study.

Advances in treatment of axial spondyloarthritis are associated with improved patient outcomes: data from the Ankylosing Spondylitis Registry of Ireland (ASRI).

The Ankylosing Spondylitis Registry of Ireland (ASRI) captures both radiographic and non-radiographic axial spondyloarthritis (axSpA) in a large, well characterised cohort. This is a valuable resource for studies in therapeutics and burden of disease, following a period of rapid change in the field of axSpA. This study aims to perform a focused analysis on patient outcomes and pattern of medication usage in axSpA.

Exercise-induced angiogenesis is dependent on metabolically primed ATF3/4 endothelial cells.

Exercise is a powerful driver of physiological angiogenesis during adulthood, but the mechanisms of exercise-induced vascular expansion are poorly understood. We explored endothelial heterogeneity in skeletal muscle and identified two capillary muscle endothelial cell (mEC) populations that are characterized by differential expression of ATF3/4. Spatial mapping showed that ATF3/4 mECs are enriched in red oxidative muscle areas while ATF3/4 ECs lie adjacent to white glycolytic fibers.

COVID-19: What Do Rheumatologists Need to Know?

Purpose Of Review: Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) emerged in December 2019, rapidly reaching global pandemic proportions. Coronavirus disease 2019 (COVID-19) has presented unique challenges to the rheumatology community. It is known that many individuals with rheumatic disease are at increased risk of severe disease from other infections, sparking a similar fear for COVID-19.

Pharmacological treatment for managing bone health in axial spondyloarthropathy: systematic review and meta-analysis.

Axial spondyloarthropathy (axSpA) is associated with an increased prevalence of osteoporosis, but no recommendations exist to guide management. This systematic review and meta-analysis aim to assess the efficacy of pharmacological and non-pharmacological interventions on bone mineral density (BMD) in axSpA. Electronic databases were searched from inception to June 2019 for randomised controlled trials (RCTs) and quasi (q)-RCTs with pharmacological and non-pharmacological interventions.

Endothelial Lactate Controls Muscle Regeneration from Ischemia by Inducing M2-like Macrophage Polarization.

Endothelial cell (EC)-derived signals contribute to organ regeneration, but angiocrine metabolic communication is not described. We found that EC-specific loss of the glycolytic regulator pfkfb3 reduced ischemic hindlimb revascularization and impaired muscle regeneration. This was caused by the reduced ability of macrophages to adopt a proangiogenic and proregenerative M2-like phenotype.

Calcaneal quantitative ultrasound has a role in out ruling low bone mineral density in axial spondyloarthropathy.

Objective: The aim of this study was to investigate the role of quantitative ultrasound (QUS) of the calcaneus in screening for osteoporosis in adults with axial spondyloarthropathy (axSpA).

Method: Postmenopausal women and men over 50 years with axSpA were recruited for this observational cross-sectional study. Dual-energy x-ray absorptiometry (DXA) assessed bone mineral density (BMD) of the spine and hip.

PHD1 controls muscle mTORC1 in a hydroxylation-independent manner by stabilizing leucyl tRNA synthetase.

mTORC1 is an important regulator of muscle mass but how it is modulated by oxygen and nutrients is not completely understood. We show that loss of the prolyl hydroxylase domain isoform 1 oxygen sensor in mice (PHD1) reduces muscle mass. PHD1 muscles show impaired mTORC1 activation in response to leucine whereas mTORC1 activation by growth factors or eccentric contractions was preserved.

Measuring bone density in axial spondyloarthropathy: Time to turn things on their side?

Aim: Osteoporosis in axial spondyloarthropathy (axSpA) is difficult to accurately diagnose due to osteoproliferation of the spine interfering with conventional (anteroposterior, AP) dual-energy X-ray absorptiometry (DXA). This study compares AP and lateral projections of DXA when assessing bone mineral density (BMD) of the spine and investigates the impact of osteoproliferation on AP DXA.

Method: In this cross-sectional study, structured standardized assessments collected demographic, clinical, laboratory and radiographic data.

Multimorbidity in Axial Spondyloarthropathy and Its Association with Disease Outcomes: Results from the Ankylosing Spondylitis Registry of Ireland Cohort.

Objective: Multimorbidity, the coexistence of 2 or more conditions in an individual, is associated with morbidity and mortality in the general population. This study aims to describe the prevalence of multimorbidity in axial spondyloarthropathy (axSpA) and assess its association with disease outcome measures.

Methods: This cross-sectional study was conducted within the Ankylosing Spondylitis Registry of Ireland (ASRI) cohort.

The Warburg Effect in Endothelial Cells and its Potential as an Anti-angiogenic Target in Cancer.

Endothelial cells (ECs) make up the lining of our blood vessels and they ensure optimal nutrient and oxygen delivery to the parenchymal tissue. In response to oxygen and/or nutrient deprivation, ECs become activated and sprout into hypo-vascularized tissues forming new vascular networks in a process termed angiogenesis. New sprouts are led by migratory tip cells and extended through the proliferation of trailing stalk cells.

The Fascinating Paradox of Osteoporosis in Axial Spondyloarthropathy.

Low bone mineral density (BMD) is a recognized feature of axial spondyloarthropathy (axSpA). However, the osteoproliferation inherent in axSpA can make traditional dual-energy x-ray absorptiometry assessment inaccurate, particularly in structurally advanced disease. As a result, much about osteoporosis in axSpA is unknown.