A periodized training attenuates thigh intermuscular fat and improves muscle quality in patients with knee osteoarthritis: results from a randomized controlled trial

Thigh muscle composition changes in knee osteoarthritis patients during weight loss: Sex-specific analysis using data from osteoarthritis initiative

OBJECTIVES

Sex of patients with knee osteoarthritis (KOA) may impact changes in thigh muscle composition during weight loss, the most well-known disease-modifying intervention. We investigated longitudinal sex-based changes in thigh muscle quality during weight loss in participants with KOA.

METHODS

Using Osteoarthritis Initiative (OAI) cohort data, we included females and males with baseline radiographic KOA who experienced > 5 % reduction in Body Mass Index (BMI) over four years. Using a previously validated deep-learning algorithm, we measured Magnetic Resonance Imaging (MRI)-derived biomarkers of thigh muscles at baseline and year-4. Outcomes were the intra- and inter-muscular adipose tissue (Intra-MAT and Inter-MAT) and contractile percentage of thigh muscles between females and males. The analysis adjusted for potential confounders, such as demographics, risk factors, BMI change, physical activity, diet, and KOA status.

RESULTS

A retrospective selection of available thigh MRIs from KOA participants who also had a 4-year weight loss (>5 % of BMI) yielded a sample comprising 313 thighs (192 females and 121 males). Female and male participants exhibited a comparable degree of weight loss (females: -9.72 ± 4.38, males: -8.83 ± 3.64, P-value=0.060). However, the changes in thigh muscle quality were less beneficial for females compared to males, as shown by a less degree of longitudinal decrease in Intra-MAT (change difference,95 %CI: 783.44 mm2/4-year, 505.70 to 1061.19, P-value<0.001) and longitudinal increase in contractile percentage (change difference,95 %CI: -3.9 %/4-year, -6.5 to -1.4, P-value=0.019).

CONCLUSIONS

In participants with KOA and 4-year weight loss, the longitudinal changes in thigh muscle quality were overall beneficial but to a less degree in females compared to males. Further research is warranted to investigate the underlying mechanisms and develop sex-specific interventions to optimize muscle quality during weight loss.

Comparative Efficacy of Various Exercise Therapies and Combined Treatments on Inflammatory Biomarkers and Morphological Measures of Skeletal Muscle among Older Adults with Knee Osteoarthritis: A Network Meta-Analysis

Osteoarthritis is associated with high risks of sarcopenia in older populations. Exercise interventions are promising treatments for musculoskeletal impairments in knee osteoarthritis (KOA). The purpose of this study was to identify the comparative effects of exercise monotherapy and its adjunct treatments on muscle volume and serum inflammation for older individuals with KOA. A literature search in the electronic databases was comprehensively performed from this study's inception until April 2024 to identify relevant randomized controlled trials (RCTs) that reported muscle morphology and inflammation outcomes after exercise. The included RCTs were analyzed through a frequentist network meta-analysis (NMA). The standard mean difference (SMD) with a 95% confidence interval was estimated for treatment effects on muscle morphology and inflammation biomarkers. The relative effects on each main outcome among all treatment arms were compared using surface under the cumulative ranking (SUCRA) scores. The certainty of evidence (CoE) was assessed by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) ranking system. Probable moderators of the treatment efficacy were investigated by network meta-regression analysis. This study included 52 RCTs (4255 patients) for NMA. Among the 27 identified treatment arms, isokinetic training plus physical modality as well as low-load resistance training plus blood-flow restriction yielded the most optimal treatment for inflammation reduction (-1.89; SUCRA = 0.97; CoE = high) and muscle hypertrophy (SMD = 1.28; SUCRA = 0.94; CoE = high). The patient's age (β = -0.73), the intervention time (β = -0.45), and the follow-up duration (β = -0.47) were identified as significant determinants of treatment efficacy on muscle hypertrophy. Exercise therapy in combination with noninvasive agents exert additional effects on inflammation reduction and muscle hypertrophy compared to its corresponding monotherapies for the KOA population. However, such treatment efficacy is likely moderated by the patient's age, the intervention time, and the follow-up duration.

Fibro-adipogenic progenitors in physiological adipogenesis and intermuscular adipose tissue remodeling

Excessive accumulation of intermuscular adipose tissue (IMAT) is a common pathological feature in various metabolic and health conditions and can cause muscle atrophy, reduced function, inflammation, insulin resistance, cardiovascular issues, and unhealthy aging. Although IMAT results from fat accumulation in muscle, the mechanisms underlying its onset, development, cellular components, and functions remain unclear. IMAT levels are influenced by several factors, such as changes in the tissue environment, muscle type and origin, extent and duration of trauma, and persistent activation of fibro-adipogenic progenitors (FAPs). FAPs are a diverse and transcriptionally heterogeneous population of stromal cells essential for tissue maintenance, neuromuscular stability, and tissue regeneration. However, in cases of chronic inflammation and pathological conditions, FAPs expand and differentiate into adipocytes, resulting in the development of abnormal and ectopic IMAT. This review discusses the role of FAPs in adipogenesis and how they remodel IMAT. It highlights evidence supporting FAPs and FAP-derived adipocytes as constituents of IMAT, emphasizing their significance in adipose tissue maintenance and development, as well as their involvement in metabolic disorders, chronic pathologies and diseases. We also investigated the intricate molecular pathways and cell interactions governing FAP behavior, adipogenesis, and IMAT accumulation in chronic diseases and muscle deconditioning. Finally, we hypothesize that impaired cellular metabolic flexibility in dysfunctional muscles impacts FAPs, leading to IMAT. A deeper understanding of the biology of IMAT accumulation and the mechanisms regulating FAP behavior and fate are essential for the development of new therapeutic strategies for several debilitating conditions.

Erosive hand osteoarthritis and sarcopenia: data from Osteoarthritis Initiative cohort

OBJECTIVES

There is no evidence linking specific osteoarthritis (OA) types, such as erosive hand OA (EHOA), with distant generalised changes in muscle composition (sarcopenia), which can potentially be modified. This study pioneers the exploration of the association between EHOA and sarcopenia, both of which are predominantly observed in the older adults.

METHODS

Using the Osteoarthritis Initiative cohort, we selected hand OA (modified Kellgren and Lawrence (grade ≥2 in ≥1 hand joint) participants with radiographic central erosions in ≥1 joints (EHOA group) and propensity score-matched hand OA participants with no erosion (non-EHOA group). MRI biomarkers of thigh muscles were measured at baseline, year 2 and year 4 using a validated deep-learning algorithm. To adjust for 'local' effects of coexisting knee OA (KOA), participants were further stratified according to presence of radiographic KOA. The outcomes were the differences between EHOA and non-EHOA groups in the 4-year rate of change for both intramuscular adipose tissue (intra-MAT) deposition and contractile (non-fat) area of thigh muscles.

RESULTS

After adjusting for potential confounders, 844 thighs were included (211 EHOA:633 non-EHOA; 67.1±7.5 years, female/male:2.9). Multilevel mixed-effect regression models showed that EHOA is associated a different 4-year rate of change in intra-MAT deposition (estimate, 95% CI: 71.5 mm2/4 years, 27.9 to 115.1) and contractile area (estimate, 95% CI: -1.8%/4 years, -2.6 to -1.0) of the Quadriceps. Stratified analyses showed that EHOA presence is associated with adverse changes in thigh muscle quality only in participants without KOA.

CONCLUSIONS

EHOA is associated with longitudinal worsening of thigh muscle composition only in participants without concomitant KOA. Further research is needed to understand the systemic factors linking EHOA and sarcopenia, which unlike EHOA is modifiable through specific interventions.

Longitudinal Changes in Quadriceps Morphology over the First 3 Months after Anterior Cruciate Ligament Reconstruction

PURPOSE

Neuromuscular deficits and atrophy after anterior cruciate ligament reconstruction (ACLR) may be accompanied by changes in muscle composition and poor quadriceps muscle quality (QMQ). Quadriceps atrophy occurs after ACLR but improves within the first three postoperative months, yet this hypertrophy could be attributable to increases in noncontractile tissue (i.e., poor QMQ). The purposes of this study were to evaluate changes in QMQ after ACLR and to determine if changes in QMQ and cross-sectional area (CSA) occur in parallel or independently.

METHODS

A longitudinal prospective cohort design was implemented to evaluate QMQ and CSA in 20 individuals with ACLR and 12 healthy controls. Participants completed three testing sessions (baseline/presurgery, 1 month, and 3 months) during which ultrasound images were obtained from the vastus lateralis (VL) and rectus femoris (RF). QMQ was calculated as the echo intensity (EI) of each image, with high EI representing poorer QMQ. Anatomical CSA was also obtained from each image.

RESULTS

RF and VL EI were greater at 1 and 3 months in the ACLR limb compared with baseline and the contralateral limb and did not change between 1 and 3 months. VL and RF CSA in the ACLR limb were smaller at 1 and 3 months compared with the contralateral limb and controls (VL only) but increased from 1 to 3 months. Changes in QMQ and CSA were not correlated.

CONCLUSIONS

QMQ declines within the first month after ACLR and does not improve by 3 months although hypertrophy occurs, suggesting that these morphological characteristics change independently after ACLR. Poorer QMQ represents greater concentration of noncontractile tissues within the muscle and potentially contributes to chronic quadriceps dysfunction observed after ACLR.

Effects of neuromuscular control and strengthening exercises on MRI-measured thigh tissue composition and muscle properties in people with knee osteoarthritis - an exploratory secondary analysis from a randomized controlled trial

OBJECTIVE

To investigate the effects of adding strength training to neuromuscular control exercises on thigh tissue composition and muscle properties in people with radiographic-symptomatic knee osteoarthritis (KOA).

METHODS

In this exploratory secondary analysis of a randomized controlled trial, using a complete-case approach, participants performed 12 weeks of twice-weekly neuromuscular control exercise and patient education (NEMEX, n = 34) or NEMEX plus quadriceps strength training (NEMEX+ST, n = 29). Outcomes were MRI-measured inter- and intramuscular adipose tissue (InterMAT, IntraMAT), quadriceps muscle cross-sectional area (CSA), knee-extensor strength, specific strength (strength/lean CSA) and 30 s chair-stands. Between-group effects were compared using a mixed model analysis of variance.

RESULTS

At 12 weeks, responses to NEMEX+ST overlapped with NEMEX for all outcomes. Both groups reduced InterMAT (NEMEX+ST=25 %, NEMEX=21 %); between-group difference: 0.8cm2 (95 % CI: -0.1, 1.7). NEMEX+ST decreased IntraMAT (2 %) and NEMEX increased IntraMAT (4 %); between-group difference 0.1 %-points (-0.3, 0.5). Both groups increased quadriceps CSA and lean CSA (CSA minus IntraMAT), improved knee-extensor strength and specific strength, and improved chair-stand performance with a trend towards greater effects in NEMEX+ST.

CONCLUSION

Adding strength training to 12 weeks of neuromuscular control exercises provided largely similar effects to neuromuscular control exercises alone in decreasing InterMAT and IntraMAT, in improving knee-extensor strength, CSA and in improving performance-based function in KOA persons, with a trend towards greater effects with additional strength training. Notably, both groups substantially reduced InterMAT and improved specific strength (an index of muscle quality). Our hypothesis-generating work warrants exploration of the roles played by InterMAT and IntraMAT in exercise effects in KOA.

Quadriceps composition and function influence downhill gait biomechanics >1 year following anterior cruciate ligament reconstruction

BACKGROUND

Quadriceps dysfunction is common following anterior cruciate ligament reconstruction and contributes to aberrant gait biomechanics. Changes in quadriceps composition also occur in these patients including greater concentrations of non-contractile tissue. The purpose of this study was to evaluate associations between quadriceps composition, function, and gait biomechanics in individuals with anterior cruciate ligament reconstruction.

METHODS

Forty-eight volunteers with anterior cruciate ligament reconstruction completed gait biomechanics and quadriceps function and composition assessments. Gait biomechanics were sampled during downhill walking (-10° slope) on an instrumented treadmill. Quadriceps function (peak torque and rate of torque development) was assessed via maximal isometric contractions, while composition was evaluated via ultrasound echo intensity.

FINDINGS

Greater quadriceps peak torque was associated with a greater peak knee extension moment (r = 0.365, p = 0.015). Greater vastus lateralis echo intensity (i.e. poorer muscle quality) was associated with less knee flexion displacement (r = -0.316, p = 0.032). Greater echo intensity of the vastus lateralis (r = -0.298, p = 0.044) and rectus femoris (r = -0.322, p = 0.029) was associated with a more abducted knee angle at heel strike. Quadriceps peak torque explained 11-16% of the variance in echo intensity.

INTERPRETATION

Both quadriceps function and composition influence aberrant gait biomechanics following anterior cruciate ligament reconstruction. Quadriceps composition appears to provide insight into quadriceps dysfunction independent of muscle strength, as they associated with different gait biomechanics outcomes and shared minimal variance. Future research is necessary to determine the influence of changes in quadriceps composition on joint health outcomes.

Effect of intramuscular fat in the thigh muscles on muscle architecture and physical performance in the middle-aged women with knee osteoarthritis

BACKGROUND

We investigated intramuscular fat (IMF) in quadriceps femoris (QF) and hamstring muscles in the middle-aged women with knee osteoarthritis (KOA). We also examined the relationship between muscular infiltration of QF and hamstring muscles and muscle architecture and physical performance of the women with KOA.

METHODS

In this cross-sectional study, 72 women were included. Body muscle and fat mass were measured by BIA, isometric muscle strength was evaluated by hand-held dynamometer. IMF and muscle architecture were calculated from rectus femoris (RF), vastus intermedius (VIM), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), semitendinosus (ST) and semimembranosus (SM) using B-mode ultrasonography. KOA-related symptoms and functions were assessed with KOOS. The functional performance assessments were evaluated with Stair Climbing Test, 20-Meter Walking Test.

RESULTS

Women with KOA had more IMF in RF, VIM, VL, VM and BF, ST, SM muscles compared to the healthy women. Pennation angles decreased as the IMF in the RF, VM, BF and ST decreased. As the IMF of the RF and VM increased isometric knee extensor strength decreased and KOOS symptom score, pain score and ADL score increased in women with KOA. Walking and stair climbing speed deteriorated as the IMF in RF, VIM, VM, BF increased in the middle-aged women. As the IMF in BF increased isometric knee flexor strength decreased and KOOS scores increased. Physical performance scores deteriorated as the IMF in BF increased in middle-aged women with KOA.

CONCLUSION

IMF in QF and hamstring muscles were higher in the middle-aged women with KOA group compared with that in the healthy group. Weakness of the QF and hamstring muscles may due to the changes in architectural properties of muscle depending on muscular infiltration. IMF in knee muscles is an important determining factor in performance and physical function of middle-aged women with KOA.

Face-to-face and telerehabilitation delivery of circuit training have similar benefits and acceptability in patients with knee osteoarthritis: a randomised trial

QUESTION

Is periodised circuit training delivered via a telerehabilitation model of care as effective as the same training applied face-to-face for improving pain intensity, physical function, muscle strength, pain catastrophising, body composition, intermuscular adipose tissue and muscle architecture in people with knee osteoarthritis (OA)?

DESIGN

Randomised controlled, non-inferiority trial with concealed allocation, blinded assessors and intention-to-treat analysis.

PARTICIPANTS

One hundred adults aged ≥ 40 years with knee OA and pain for ≥ 3 months, with current pain ≥ 40 mm on a 100-mm visual analogue scale (VAS).

INTERVENTION

The experimental group received 14 weeks of circuit training delivered via telerehabilitation using video recordings, followed by periodic phone calls in order to motivate and instruct participants. The control group received the same circuit training program in a face-to-face format.

OUTCOME MEASURES

The primary outcomes were pain VAS and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale, measured at 14 weeks. Secondary outcomes included objective physical function, strength, pain catastrophising and morphological measures (muscle architecture and thigh and body composition). Outcomes were measured at 14 and 26 weeks.

RESULTS

Periodised circuit training delivered via telerehabilitation had equivalent effects to face-to-face delivery for pain intensity, physical function, muscle strength, pain catastrophising, thigh composition, intermuscular adipose tissue and muscle architecture. Whole body composition did not change appreciably in either group. Adherence to the training was excellent and participants in each group reported good perceptions of their randomised intervention.

CONCLUSION

A periodised circuit training protocol can be delivered to people with knee OA in their own homes, using available technology while maintaining high levels of acceptability. More importantly, telerehabilitation appears to cause non-inferior physical and functional outcomes to face-to-face rehabilitation programs.

TRIAL REGISTRATION

RBR-662hn2.

Dose-Response Relationships of Resistance Training in Adults With Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND AND PURPOSE

To determine the effects of resistance training (RT) on symptoms, function, and lower limb muscle strength in patients with knee osteoarthritis (KOA), and to determine the optimal dose-response relationships.

DATA SOURCES

We searched the PubMed, MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and ClinicalTrials.gov databases from inception to January 23, 2022.

ELIGIBILITY CRITERIA

Randomized controlled trials that examined the effects of RT in KOA patients (mean age ≥50 years) were included.

DATA SYNTHESIS

We applied Hedges' g of the random-effects model to calculate the between-subject standardized mean difference (SMDbs). A random-effects metaregression was calculated to explain the influence of key training variables on the effectiveness of RT. We used the Grading of Recommendations Assessments, Development and Evaluation (GRADE) method to appraise the certainty of evidence.

RESULTS

A total of 46 studies with 4289 participants were included. The analysis revealed moderate effects of RT on symptoms and function (SMDbs =-0.52; 95% CI: -0.64 to -0.40), and lower limb muscle strength (SMDbs = 0.53; 95% CI: 0.42 to 0.64) in the intervention group compared with the control group. The results of the metaregression revealed that only the variable "training period" (P< .001) had significant effects on symptoms, function, and lower limb muscle strength, and the 4 to 8 weeks of training subgroup showed greater effects than other subgroups (SMDbs =-0.70, -0.91 to -0.48; SMDbs = 0.76, 0.56 to 0.96).

CONCLUSIONS

Compared with inactive treatments, RT is strongly recommended to improve symptoms, function, and muscle strength in individuals with KOA. Dose-response relationship analysis showed that 4 to 8 weeks of RT had more benefits.

Aerobic and Resistance Training Attenuate Differently Knee Joint Damage Caused by a High-Fat-High-Sucrose Diet in a Rat Model

OBJECTIVE

Obesity and associated low-level local systemic inflammation have been linked to an increased rate of developing knee osteoarthritis (OA). Aerobic exercise has been shown to protect the knee from obesity-induced joint damage. The aims of this study were to determine (1) if resistance training provides beneficial metabolic effects similar to those previously observed with aerobic training in rats consuming a high-fat/high-sucrose (HFS) diet and (2) if these metabolic effects mitigate knee OA in a diet-induced obesity model in rats.

DESIGN

Twelve-week-old Sprague-Dawley rats were randomized into 4 groups: (1) a group fed an HFS diet subjected to aerobic exercise (HFS+Aer), (2) a group fed an HFS diet subjected to resistance exercise (HFS+Res), (3) a group fed an HFS diet with no exercise (HFS+Sed), and (4) a chow-fed sedentary control group (Chow+Sed). HFS+Sed animals were heavier and had greater body fat, higher levels of triglycerides and total cholesterol, and more joint damage than Chow+Sed animals.

RESULTS

The HFS+Res group had higher body mass and body fat than Chow+Sed animals and higher OA scores than animals from the HFS+Aer group. Severe bone lesions were observed in the HFS+Sed and Chow+Sed animals at age 24 weeks, but not in the HFS+Res and HFS+Aer group animals.

CONCLOSION

In summary, aerobic training provided better protection against knee joint OA than resistance training in this rat model of HFS-diet-induced obesity. Exposing rats to exercise, either aerobic or resistance training, had a protective effect against the severe bone lesions observed in the nonexercised rats.

Levothyroxine use and longitudinal changes in thigh muscles in at-risk participants for knee osteoarthritis: preliminary analysis from Osteoarthritis Initiative cohort

BACKGROUND

We examined the association between levothyroxine use and longitudinal MRI biomarkers for thigh muscle mass and composition in at-risk participants for knee osteoarthritis (KOA) and their mediatory role in subsequent KOA incidence.

METHODS

Using the Osteoarthritis Initiative (OAI) data, we included the thighs and corresponding knees of participants at risk but without established radiographic KOA (baseline Kellgren-Lawrence grade (KL) < 2). Levothyroxine users were defined as self-reported use at all annual follow-up visits until the 4th year and were matched with levothyroxine non-users for potential confounders (KOA risk factors, comorbidities, and relevant medications covariates) using 1:2/3 propensity score (PS) matching. Using a previously developed and validated deep learning method for thigh segmentation, we assessed the association between levothyroxine use and 4-year longitudinal changes in muscle mass, including cross-sectional area (CSA) and muscle composition biomarkers including intra-MAT (within-muscle fat), contractile percentage (non-fat muscle CSA/total muscle CSA), and specific force (force per CSA). We further assessed whether levothyroxine use is associated with an 8-year risk of standard KOA radiographic (KL ≥ 2) and symptomatic incidence (incidence of radiographic KOA and pain on most of the days in the past 12 months). Finally, using a mediation analysis, we assessed whether the association between levothyroxine use and KOA incidence is mediated via muscle changes.

RESULTS

We included 1043 matched thighs/knees (266:777 levothyroxine users:non-users; average ± SD age: 61 ± 9 years, female/male: 4). Levothyroxine use was associated with decreased quadriceps CSAs (mean difference, 95%CI: - 16.06 mm2/year, - 26.70 to - 5.41) but not thigh muscles' composition (e.g., intra-MAT). Levothyroxine use was also associated with an increased 8-year risk of radiographic (hazard ratio (HR), 95%CI: 1.78, 1.15-2.75) and symptomatic KOA incidence (HR, 95%CI: 1.93, 1.19-3.13). Mediation analysis showed that a decrease in quadriceps mass (i.e., CSA) partially mediated the increased risk of KOA incidence associated with levothyroxine use.

CONCLUSIONS

Our exploratory analyses suggest that levothyroxine use may be associated with loss of quadriceps muscle mass, which may also partially mediate the increased risk of subsequent KOA incidence. Study interpretation should consider underlying thyroid function as a potential confounder or effect modifier. Therefore, future studies are warranted to investigate the underlying thyroid function biomarkers for longitudinal changes in the thigh muscles.

Diabetes-associated thigh muscle degeneration mediates knee osteoarthritis-related outcomes: results from a longitudinal cohort study

OBJECTIVES

We examined the association between diabetes mellitus (DM) and longitudinal MRI biomarkers for thigh muscle degeneration in patients with knee osteoarthritis (KOA) and their mediatory role in worsening KOA-related symptoms.

METHODS

The Osteoarthritis Initiative (OAI) participants with radiographic KOA (Kellgren-Lawrence grade ≥ 2) were included. Thighs and corresponding knees of KOA patients with versus without self-reported DM were matched for potential confounders using propensity score (PS) matching. We developed and used a validated deep learning method for longitudinal thigh segmentation. We assessed the association of DM with 4-year longitudinal muscle degeneration in biomarkers of muscle cross-sectional area (CSA) and contractile percentage (non-fat CSA/total CSA). We further investigated whether DM is associated with 9-year risk of KOA radiographic progression, knee replacement (KR), and symptoms worsening. Finally, we evaluated whether the DM-KOA worsening association is mediated through preceding muscle degeneration.

RESULTS

After PS matching, 698 thighs/knees were included (185:513 with:without DM; average ± SD age:64 ± 8-years; female/male:1.4). Baseline DM was associated with a decreased contractile percent of total thigh muscles and quadriceps (mean difference, 95%CI -0.16%/year, -0.25 to -0.07, and -0.21%/year, -0.33 to -0.08). DM was also associated with an increased risk of worsening KOA-related symptoms (hazard ratio, 95%CI 1.70, 1.18-2.46) but not radiographic progression or KR. The decrease in quadriceps contractile percent partially mediated the increased risk of symptoms worsening in patients with DM.

CONCLUSIONS

Baseline DM is associated with thigh muscle degeneration and KOA-related symptoms worsening. As a potentially modifiable risk factor, DM-associated longitudinal thigh muscle degeneration may partially mediate the symptoms worsening in patients with DM and coexisting KOA.

KEY POINTS

• Diabetes mellitus (DM) is associated with worsening knee osteoarthritis (KOA)-related symptoms. • As a potentially modifiable factor, DM-associated thigh muscle (quadriceps) degeneration partially mediates the worsening of KOA-related symptoms.

Muscle transcriptomic circuits linked to periarticular physiology in end-stage osteoarthritis

The ability of individuals with end-stage osteoarthritis (OA) to functionally recover from total joint arthroplasty is highly inconsistent. The molecular mechanisms driving this heterogeneity have yet to be elucidated. Furthermore, OA disproportionately impacts females, suggesting a need for identifying female-specific therapeutic targets. We profiled the skeletal muscle transcriptome in females with end-stage OA (n = 20) undergoing total knee or hip arthroplasty using RNA-Seq. Single-gene differential expression (DE) analyses tested for DE genes between skeletal muscle overlaying the surgical (SX) joint and muscle from the contralateral (CTRL) leg. Network analyses were performed using Pathway-Level Information ExtractoR (PLIER) to summarize genes into latent variables (LVs), i.e., gene circuits, and link them to biological pathways. LV differences in SX versus CTRL muscle and across sources of muscle tissue (vastus medialis, vastus lateralis, or tensor fascia latae) were determined with ANOVA. Linear models tested for associations between LVs and muscle phenotype on the SX side (inflammation, function, and integrity). DE analysis revealed 360 DE genes (|Log2 fold-difference| ≥ 1, FDR ≤ 0.05) between the SX and CTRL limbs, many associated with inflammation and lipid metabolism. PLIER analyses revealed circuits associated with protein degradation and fibro-adipogenic cell gene expression. Muscle inflammation and function were linked to an LV associated with endothelial cell gene expression highlighting a potential regulatory role of endothelial cells within skeletal muscle. These findings may provide insight into potential therapeutic targets to improve OA rehabilitation before and/or following total joint replacement.

Effects of Circuit Training on Patients with Knee Osteoarthritis: A Systematic Review and Meta-Analysis

The most prevalent joint disease is osteoarthritis (OA), which affects an estimated 240 million individuals worldwide. Knee osteoarthritis (KOA) is one of the top 10 causes of disability worldwide. The aim of this study is to systematically evaluate the effect of circuit training (CT) on patients with KOA. We searched through PubMed, Scopus, ScienceDirect, Cochrane, and Google Scholar up to 12 February 2022. We used random-effects statistical analysis for continuous variables and reported the results as a standardized mean difference (SMD) with 95 percent confidence intervals (CI). Seven trials involving 346 patients were included. A significant improvement in the intervention group was observed for the parameter, pain level (SMD -0.96, 95% CI -1.77 to -0.14; p = 0.02; seven trials, 346 participants; high quality evidence), while no significant improvement was found in physical function (SMD 0.03, 95% CI -0.44-0.50; p = 0.89; five trials, 294 participants; high-quality evidence), quality of life (SMD -0.25, 95% CI -1.18-0.68; p = 0.60; three trials, 205 participants; high-quality evidence), the activity of daily living (SMD 0.81, 95% CI -0.85-2.48; p = 0.34; three trials, 223 participants; high-quality evidence), and knee stiffness (SMD -0.65, 95% CI -1.96-0.66; p = 0.33; two trials, 71 participants; high-quality evidence). The findings in this meta-analysis suggest that CT could effectively complement the conventional treatment of KOA, particularly in alleviating pain. However, comprehensive data on the guidelines for the CT approach would be needed to adequately examine the effects of CT on quality of life and biochemical markers in patients with KOA.

Role of Thigh Muscle Changes in Knee Osteoarthritis Outcomes: Osteoarthritis Initiative Data

Background Longitudinal data on the association of quantitative thigh muscle MRI markers with knee osteoarthritis (KOA) outcomes are scarce. These associations are of clinical importance, with potential use for thigh muscle-directed disease-modifying interventions. Purpose To measure KOA-associated longitudinal changes in MRI-derived muscle cross-sectional area (CSA) and adipose tissue and their association with downstream symptom worsening and knee replacement (KR). Materials and Methods In a secondary analysis of the Osteoarthritis Initiative multicenter prospective cohort (February 2004 through October 2015), knees of participants with available good-quality thigh MRI scans at baseline and at least one follow-up visit were included and classified as with and without KOA according to baseline radiographic Kellgren-Lawrence grade of 2 or higher and matched for confounders with use of propensity score matching. An automated deep learning model for thigh MRI two-dimensional segmentation was developed and tested. Markers of muscle CSA and intramuscular adipose tissue (intra-MAT) were measured at baseline and 2nd- and 4th-year follow-up (period 1) and compared between knees with and without KOA by using linear mixed-effect regression models. Furthermore, in knees with KOA, the association of period 1 changes in muscle markers with risk of KR (Cox proportional hazards) and symptom worsening (mixed-effect models) during the 4th to 9th year (period 2) was evaluated. Results This study included 4634 matched thighs (2317 with and 2317 without KOA) of 2344 participants (mean age, 62 years ± 9 [SD]; 1292 women). Compared with those without, knees with KOA had a decrease in quadriceps CSA (mean difference, -8.21 mm2/year; P = .004) and an increase in quadriceps intra-MAT (1.98 mm2/year; P = .007). Decreased CSA and increased intra-MAT of quadriceps during period 1 was predictive of downstream (period 2) KOA symptom worsening (Western Ontario and McMaster Universities Osteoarthritis Index total score: odds ratio, 0.24 [negative association] [P < .001] and 1.38 [P = .012], respectively). Quadriceps CSA changes were negatively associated with higher future KR risk (hazard ratio, 0.70; P < .001). Conclusion Knee osteoarthritis was associated with longitudinal MRI-derived decreased quadriceps cross-sectional area and increased intramuscular adipose tissue. These potentially modifiable risk factors were predictive of downstream symptom worsening and knee replacement. Clinical trial registration no. NCT00080171 © RSNA, 2022 Online supplemental material is available for this article.

Features of trunk muscle wasting during acute care and physical function recovery with aortic disease

BACKGROUND

Low skeletal muscle area or density, such as myosteatosis, identified on computed tomography (CT) is associated with poor prognosis in patients with cardiovascular diseases. However, there is a lack of evidence regarding the clinical process of skeletal muscle decline as a short-term change during acute care settings. This study focused on the use of routine CT imaging for aortic disease management and investigated the changes in skeletal muscle before and after acute care.

METHODS

This prospective study included 123 patients who underwent abdominal CT before and after acute care. The all-abdominal and each abdominal muscle areas were divided into eight parts (e.g. rectus abdominis, psoas, and erector spine), and their areas and densities were measured at the third lumbar vertebra level after the patients were discharged and de-identified with blinding to avoid measurement bias. Short physical performance battery (SPPB) was measured at the start and end of in-hospital cardiac rehabilitation. A generalized linear model with patients as random effects was made to investigate skeletal muscle loss during acute care. Multivariate linear regression analysis was also used to assess the relationship between the change in skeletal muscle during acute care and SPPB during in-hospital cardiac rehabilitation.

RESULTS

The median age of the patients was 70 (interquartile: 58-77) years, and 69.9% (86/123) were men. The median day between acute care from the day of surgery or hospital admission and follow-up CT was 7 (interquartile: 3-8) days. Overall muscle density declined after acute care (estimate value: -3.640, 95% confidence interval [CI]: -4.538 to -2.741), and each abdominal muscle density consistently declined (interaction: F value = 0.099, P = 0.998). In contrast, there was no significant change in the overall muscle area (estimate value: -0.863, 95% CI: -2.925 to 1.200). Changes in the muscle area were different for each skeletal muscle (interaction: F value = 2.142, P = 0.037), and only the erector spine muscle significantly declined (estimate value: -1.836, 95% CI: -2.507 to -1.165). After adjusting for confounding factors, a greater decline in muscle density was associated with lower recovery score on SPPB (β = 0.296, 95% CI: 0.066 to 0.400).

CONCLUSIONS

Muscle density consistently declined after acute care, especially the erector spine muscles, which also significantly decreased in size. A higher decline in muscle density was associated with a slower recovery of physical function during in-hospital cardiac rehabilitation in patients with aortic diseases.

Cross-sectional area of erector spinae muscles is associated with activities of daily living at discharge in middle- to older-aged patients with coronavirus disease 2019

Objectives

Measurement of skeletal muscle wasting using computed tomography (CT) is widely known to be useful in predicting prognosis. Although some reports have been found in patients with coronavirus disease 2019 (COVID-19), few reports have focused on the ability to perform activities of daily living (ADLs). This study retrospectively investigated the relationship between the erector spinae muscle area measured from CT images and ADL at the time of hospital discharge in patients with COVID-19.

Methods

Among patients aged 40 years or older, 271 patients (median age, 65 years; 180/271 male patients) who had CT cross-sectional images of the 12th thoracic vertebral level on admission were included. The Katz index was used to assess ADLs, and patients who were not completely independent were defined as dependent. Multivariable logistic and Poisson regression analyses were applied to examine the relationship between the cross-sectional area of the erector spinae muscles and the onset of ADL dependence at discharge.

Results

A total of 75 (27.7%) patients became dependent on ADL at the time of hospital discharge. Decreased erector spinae muscle area was significantly related to dependent ADL at discharge (adjusted odds ratio: 0.886, 95% confidence interval: 0.805–0.975). In addition, the erector spinae muscle area was significantly related to the number of ADL items for which independence was not achieved (adjusted incidence rate ratio: 0.959, P < 0.001).

Conclusions

The cross-sectional area of the erector spinae muscles from the thoracic CT image was associated with the ability to perform basic ADL at hospital discharge.

Effects of a periodized circuit training protocol delivered by telerehabilitation compared to face-to-face method for knee osteoarthritis: a protocol for a non-inferiority randomized controlled trial

BACKGROUND

Regular exercise is an effective method for reducing pain and disability in patients with knee osteoarthritis (OA), as well as improving body composition. Thus, a combination of both resistance and aerobic training (circuit training) has shown to be promising for this population. However, access to physical therapy is limited by physical distance, social isolation, and/or treatment costs. Remote rehabilitation seems to be an effective way to minimize these barriers, but the benefits are dependent on the participants' adherence to the interventions provided at a distance. The objectives of this protocol are to compare the effects of a periodized circuit training applied via telerehabilitation with the same protocol applied in the face-to-face model for individuals with knee OA.

METHODS

This study presents a single-blinded protocol for a non-inferiority randomized controlled trial. One hundred participants diagnosed with knee OA (grades II and III Kellgren and Lawrence system), aged 40 years or more, and BMI < 30 kg/m2 will be randomly divided into two groups: telerehabilitation (TR) and face-to-face (FtF) circuit training. The FtF group will perform a 14-week periodized circuit training protocol supervised by a physical therapist, 3 times a week. The TR group will perform the same exercise protocol at home, at least 3 times a week. In addition, the TR group will be able to follow the execution and orientations of the exercises by DVD, a website, and online file sharing tools, and they will receive periodic phone calls in order to motivate, clarify, and inform some aspects of knee OA. The primary outcomes are changes in self-reported pain intensity (visual analog scale (VAS)) and physical function (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), with a primary end-point of 14 weeks and a secondary end-point of 26 weeks. Secondary outcomes include changes in other clinical outcomes, in morphological characteristics, adherence, acceptability, and treatment perspective.

DISCUSSION

A circuit training through telerehabilitation may contribute to developing early intervention in the causative and potentiating factors of the knee OA, verifying the effects of a low-cost, non-pharmacological and non-invasive treatment.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (ReBEC) ID: RBR-662hn2. Registered on 31 March 2019. Link: http://www.ensaiosclinicos.gov.br ; Universal Trial Number (UTN) of World Health Organization: U1111-1230-9517.

Exercise Training to Decrease Ectopic Intermuscular Adipose Tissue in Individuals With Chronic Diseases: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to evaluate the effect of exercise training on ectopic fat within skeletal muscle (intermuscular adipose tissue [IMAT]) in adult populations with chronic diseases.

METHODS

A literature search was conducted in relevant databases to identify randomized controlled trials (RCTs) from inception. Selected studies examined the effect of aerobic training (AET), resistance training (RT), or combined training (COM) on IMAT as assessed by noninvasive magnetic resonance imagery or computed tomography. Eligibility was determined using Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Data extraction was performed using the population (P), intervention (I), comparison (C), outcome (O), timing (T), and settings (S) approach. Methodological quality was analyzed by the Cochrane risk of bias assessment. Standardized effect sizes (ES) with 95% CIs were calculated. Heterogeneity among studies was quantified using I2 statistics. Subgroup and meta-regression analyses were included. Risk of publication bias was examined by the Egger regression test.

RESULTS

Nineteen RCTs included 962 adults (628 women; age range = 34.8-93.4 years) with different chronic conditions that participated in 10 AET, 12 RT, and 5 COM interventions. The quality of studies was deemed moderate. Overall, the effect of exercise on IMAT was small (ES = 0.24; 95% CI = 0.10 to 0.37; heterogeneity I2 = 0.0%) compared with no exercise or control interventions. Moderate-intensity AET and COM had larger ES compared with RT regardless of intensity. This effect was associated with exercise-induced body weight and fat mass losses. Subgroup analysis revealed larger ES in studies assessing IMAT by magnetic resonance imagery compared with computed tomography in adults and middle-aged individuals compared with older adults and in participants who were HIV+ compared with other diagnoses.

CONCLUSION

AET and COM of moderate intensity reduce IMAT in individuals from 18 to 65 years of age who are affected by chronic diseases. This effect is associated with exercise-induced body weight and fat mass losses. In older individuals who are frail and patients at an advanced disease stage, exercise may result in a paradoxical IMAT accumulation.

IMPACT

In people affected by chronic conditions, IMAT accumulation induces muscle mass and strength losses, decline in physical performance, inflammation, and metabolic alterations. The present study shows that moderate-intensity AET or COM prevent or reduce IMAT in these conditions. Thus, the deleterious effect of IMAT on skeletal muscle homeostasis may be reverted by a properly prescribed exercise regime. The findings of the present systematic review are critical for physical therapists and health care professionals because they emphasize the therapeutic role of exercise and provide recommendations for exercise prescription that ultimately may have a positive impact on the course of disease, recovery of functionality, and independence.

LAY SUMMARY

Aerobic exercise (eg, walking/jogging, cycling) alone or combined with resistance exercise (strength training with free-weights, kettle bells, or gym equipment) is effective in reducing fat streaks that infiltrate muscles and impair muscle function and growth, particularly in adults affected by chronic diseases.

Association of Quadriceps Adiposity With an Increase in Knee Cartilage, Meniscus, or Bone Marrow Lesions Over Three Years

OBJECTIVE

To evaluate the association of fatty infiltration of the quadriceps and vastus medialis (VM) with an increase in knee cartilage, meniscus, or bone marrow lesions, using magnetic resonance imaging (MRI) in knee osteoarthritis (OA) over 3 years.

METHODS

Participants (n = 69) with and without radiographic knee OA underwent MRI at baseline and 3 years later. Chemical shift-based water/fat MRI was used to quantify the intramuscular fat fraction and the lean anatomical cross-sectional area (ACSA) for the VM and entire quadriceps muscles. MRI images of the knee were analyzed using the semiquantitative modified whole-organ MRI score (mWORMS) grading to assess change in lesions in the articular cartilage, meniscus, and bone marrow. Logistic regression was used to assess whether baseline quadriceps and VM fat fraction and lean ACSA were associated with an increase in mWORMS scores. Odds ratios (ORs) were adjusted for age, sex, and body mass index.

RESULTS

Overall, of the 69 subjects, 43 (62%) had an increase in cartilage lesions (26 of 43), meniscus lesions (19 of 43), or bone marrow lesions (22 of 43) scores. The quadriceps (OR 2.13 [95% confidence interval (95% CI) 1.09-4.15]) and VM (OR 2.05 [95% CI 1.25-3.36]) fat fraction were both associated with an increase in cartilage, meniscus, or bone marrow lesion scores over 3 years. The association of quadriceps or VM lean ACSA with the outcomes was not significant.

CONCLUSION

These longitudinal findings using quantitative MRI methods for assessment of muscle adiposity highlight the role of quadriceps adiposity, specifically in the VM, in knee OA progression. However, studies in larger cohorts are needed to confirm these findings.

Reductions of cardiovascular and metabolic risk factors after a 14-week periodized training model in patients with knee osteoarthritis: a randomized controlled trial

INTRODUCTION/OBJECTIVE

To evaluate the effects of a periodized circuit training (CT) compared with a conventional strength training (ST) and an educational protocol (EP) on body composition, metabolic parameters, muscle strength, pain, and physical performance in patients with knee osteoarthritis (KOA).

METHOD

This study followed a randomized controlled trial design. A sample of sixty-one patients with KOA, 40-65 years old and BMI < 30 kg/m², were randomly divided into three 14-week protocols: CT, ST, or EP. The CT performed whole body exercises organized in circuit, 3 times a week. The ST performed conventional resistance exercises also 3 times a week, and the EP joined in educational meetings twice a month. Body composition (dual-energy X-ray absorptiometry (DXA)); metabolic parameters (abdominal obesity, triglyceride, HDL, blood pressure and fasting glucose), knee maximal isometric voluntary contraction (MIVC) extension and flexion, performance-based tests (40-m walk test, 30-s chair test, and stair climb test), self-reported pain, stiffness, and physical function (WOMAC) and pain catastrophism were evaluated at baseline and follow-up. Repeated measures ANOVA were used to compare differences between groups (CTxSTxEP) at the different times of assessment (baseline × follow-up). When group-time interaction was found, a one-way ANOVA, followed by a Bonferroni post hoc test, was used to compare groups in each time point; while a paired t test was used to verify the time effect in each group. Additionally, the training effect was analyzed in terms of the percent change (Δ%). Effect size was calculated for post intervention (week 14) between groups. For all analyses a significance level of 5% was adopted (p < 0.05).

RESULTS

The CT was the only protocol that presented significant lower body mass (p = 0.018; Δ% = - 1.4), fat mass (p = 0.017; Δ% = - 10.3), %fat mass (p < 0.001; Δ% = - 13.9), adipose indices (%fat trunk/%fat legs p = 0.031; Δ% = 7.8; fat mass/height² p = 0.011; Δ% = - 15.1; trunk/limb fat mass p = 0.012; Δ% = - 8.2; visceral adipose tissue (VAT) volume (cm³) p = 0.039; Δ% = - 11.6; VAT area (cm²) p = 0.044; Δ% = - 12.2), blood pressure levels (SBP p = 0.042; Δ% = - 3.4 and DBP p = 0.001; Δ% = - 4.9), higher lean mass and HDL (p < 0.001; Δ% = 5.9) compared to baseline. CT and ST presented lower WOMAC pain, stiffness and physical function (p < 0.001; Δ% = - 64.0 for CT and p < 0.001; Δ% = 0.001; Δ% = - 46.4 for ST in WOMAC total score, pain catastrophizing (p < 0.001; Δ% = - 66.7 for CT and p < 0.001; Δ% = - 61.5 for ST) a higher functional performance (30 s chair test: p < 0.001; Δ% = 45.7 for CT and p < 0.001; Δ% = 26.9 for ST; 40 m walk test: p < 0.001; Δ% = 26.7 for CT and p < 0.001; Δ% = 12.5 for ST; stair climb test: p = 0.002; Δ% = - 33.9 for CT and p < 0.001; Δ% = - 18.8 for ST) and knee extension MIVC (p < 0.001; Δ% = 21.92 for CT and p < 0.001; Δ% = 30.25 for ST).

CONCLUSION

A periodized CT model reduces visceral adipose tissue, SBP and DBP, and improves HDL, important cardiovascular and metabolic risk factors, in patients with KOA. Both trained groups (CT and ST) improve self-reported clinical symptoms, muscle strength, and physical performance in this sample.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov , NCT02761590 (registered on May 4, 2016).

KEY POINTS

• A 14-week periodized circuit training reduces visceral adipose tissue, systolic and diastolic blood pressure, and improves HDL blood levels in patients with knee osteoarthritis. • Both periodized circuit training and conventional strength training improve clinical symptoms, functional performance and muscle strength in this sample.