Bone and non-contractile soft tissue changes following open kinetic chain resistance training and testosterone treatment in spinal cord injury: an exploratory study

Musculoskeletal and body composition response to high-dose testosterone with finasteride after chronic incomplete spinal cord injury-a randomized, double-blind, and placebo-controlled pilot study

Background

High-dose testosterone replacement therapy (TRT), paired with finasteride (type II 5α-reductase inhibitor), improves body composition, muscle strength, and bone mineral density (BMD) in older men, without inducing prostate enlargement-a side effect associated with TRT. Men with spinal cord injury (SCI) exhibit neuromuscular impairment, muscle atrophy, bone loss, and increased central adiposity, along with low testosterone. However, sparse evidence supports TRT efficacy after SCI.

Methods

This parallel-group, double-blind, placebo-controlled, and randomized clinical trial (RCT) is a pilot study that enrolled men (N = 12) with low to low-normal testosterone and gait impairments after chronic motor-incomplete SCI. Participants received high-dose intramuscular TRT (testosterone-enanthate, 125 mg/week) with finasteride (5 mg/day) vs. vehicle+placebo for 12 months. Change relative to baseline was determined for body composition, musculoskeletal outcomes, and prostate size, with effect sizes calculated between groups using Hedges' g. Adverse events and feasibility were assessed.

Results

TRT + finasteride consistently increased testosterone (g = 1.16-3.08) and estradiol (g = 0.43-3.48), while concomitantly reducing dihydrotestosterone (g = 0.31-2.27). Very large effect sizes at both 6 and 12 months suggest TRT + finasteride increased whole-body fat-free (lean) mass (+3-4% vs. baseline, g = 2.12-2.14) and knee extensor (KE) whole-muscle cross-sectional area (+8-11% vs. baseline, g = 2.06-2.53) more than vehicle+placebo. Moderate-to-large effect sizes suggest TRT + finasteride increased KE maximal voluntary isometric torque (+15-40% vs. baseline, g = 0.47-1.01) and femoral neck and distal femur BMD from 6 months onward (g = 0.51-1.13), compared with vehicle+placebo, and reduced fat mass 9-14% within the whole-body, trunk, and android (visceral) regions at 12 months (g = 0.77-1.27). TRT + finasteride also produced small effect sizes favoring lesser prostate growth than vehicle+placebo (g = 0.31-0.43). The participant retention, drug compliance, and incidence and severity of adverse events were similar among the groups.

Conclusion

These data provide proof-of-concept and rationale for larger RCTs aimed at discerning the impact of TRT + finasteride on body composition, musculoskeletal health, and physical function in men with SCI, along with effect sizes and variance of responses to assist in planning subsequent trials.

Clinical trial registration

ClinicalTrials.gov, identifier NCT02248701.

Bodyweight influences the relationship between serum testosterone and bone mineral density in men with spinal cord injury

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To examine the association between serum testosterone levels (T levels) and bone mineral density after spinal cord injury (SCI).

SETTING

Medical research center.

METHODS

Body composition assessments were measured in 53 men with chronic SCI. Serum T levels were measured after an overnight fast. Total and regional bone mineral density (BMD) and bone mineral content (BMC) were measured using dual-energy X-ray absorptiometry. Participants were classified into three groups based on their body weight [<65 kg, 65-80 kg, >80 kg] or serum T levels into low (400 ng/dl), mid-normal (401-544 ng/dl) and normal (>545 ng/dl) ranges.

RESULTS

Serum T level was negatively related to body weight (r = -0.33, P = 0.016), fat mass (r = -0.46, P < 0.001) and percentage fat mass (r = -0.48, P < 0.001). There were no significant relationships between serum T levels and any of the bone health measurements. Body weight was related to total, regional (P < 0.01 for both) and knee BMD (P < 0.05). T level was only related to total and regional BMD in the group with body weight of 65-80 kg.

CONCLUSION

Testosterone has no direct relationship with BMD except within a specific weight group. However, body weight or fat mass negatively influences circulating T levels in men with SCI. The relationship between serum T levels and BMD is mediated by body weight in men with SCI.

The Clinical Management of Electrical Stimulation Therapies in the Rehabilitation of Individuals with Spinal Cord Injuries

Background: People with spinal cord injuries (SCIs) often have trouble remaining active because of paralysis. In the past, exercise recommendations focused on the non-paralyzed muscles in the arms, which provides limited benefits. However, recent studies show that electrical stimulation can help engage the paralyzed extremities, expanding the available muscle mass for exercise. Methods: The authors provide an evidence-based approach using expertise from diverse fields, supplemented by evidence from key studies toward the management of electrical stimulation therapies in individuals with SCIs. Literature searches were performed separately using the PubMed, Medline, and Google Scholar search engines. The keywords used for the searches included functional electrical stimulation cycling, hybrid cycling, neuromuscular electrical stimulation exercise, spinal cord injury, cardiovascular health, metabolic health, muscle strength, muscle mass, bone mass, upper limb treatment, diagnostic and prognostic use of functional electrical stimulation, tetraplegic hands, and hand deformities after SCI. The authors recently presented this information in a workshop at a major rehabilitation conference. Additional information beyond what was presented at the workshop was added for the writing of this paper. Results: Functional electrical stimulation (FES) cycling can improve aerobic fitness and reduce the risk of cardiovascular and metabolic diseases. The evidence indicates that while both FES leg cycling and neuromuscular electrical stimulation (NMES) resistance training can increase muscle strength and mass, NMES resistance training has been shown to be more effective for producing muscle hypertrophy in individual muscle groups. The response to the electrical stimulation of muscles can also help in the diagnosis and prognosis of hand dysfunction after tetraplegia. Conclusions: Electrical stimulation activities are safe and effective methods for exercise and testing for motor neuron lesions in individuals with SCIs and other paralytic or paretic conditions. They should be considered part of a comprehensive rehabilitation program in diagnosing, prognosing, and treating individuals with SCIs to improve function, physical activity, and overall health.

Neuromuscular disorders in women and men with spinal cord injury are associated with changes in muscle and tendon architecture

OBJECTIVE

The present study aimed to determine the association between neuromuscular function, motor function impairment, and muscle and tendon structures in individuals with spinal cord injury (SCI) compared to a control (non-disabled) population.

DESIGN

A cross-sectional study with a control group.

SETTING

Center of Adapted Sports Training and Special Physical Education.

PARTICIPANTS

Fifteen individuals with SCI and motor function impairments participated in the study. A paired non-disabled group was recruited for comparison.

INTERVENTIONS

Not applicable.

OUTCOME MEASURES

Muscle (biceps brachii, rectus femoris, vastus lateralis, vastus medialis, and tibialis anterior) and tendon (quadriceps and patellar tendons) structures were assessed by ultrasound imaging (thickness, pennation angle, fascicle length, and echogenicity). Neuromuscular electrophysiological disorders were also assessed using electrodiagnosis techniques (stimulus non-responsivity and chronaxie) in the same muscles.

RESULTS

Except for the biceps brachii muscle, muscle thickness, pennation angle, and fascicle length were lower (p < 0.01) while echogenicity and chronaxie were greater (p < 0.01) in SCI participants. The SCI participants had a higher prevalence of neuromuscular electrophysiological disorders for all muscles, except the biceps brachii.

CONCLUSION

Neuromuscular disorders occur in association with muscle and tendon maladaptation in individuals with chronic SCI. A higher prevalence of electrophysiological disorders suggests an acquired polyneuromyopathy for muscles with motor function impairment even though the muscle was innerved, in addition to widespread muscle atrophy.

Predictors of muscle hypertrophy responsiveness to electrically evoked resistance training after spinal cord injury

The purpose of the study was to identify potential predictors of muscle hypertrophy responsiveness following neuromuscular electrical stimulation resistance training (NMES-RT) in persons with chronic spinal cord injury (SCI). Data for twenty individuals with motor complete SCI who completed twice weekly NMES-RT lasting 12-16 weeks as part of their participation in one of two separate clinical trials were pooled and retrospectively analyzed. Magnetic resonance imaging (MRI) was used to measure muscle cross-sectional area (CSA) of the whole thigh and knee extensor muscle before and after NMES-RT. Muscle biopsies and fasting biomarkers were also measured. Following the completion of the respective NMES-RT trials, participants were classified into either high-responders (n = 8; muscle CSA > 20%) or low-responders (n = 12; muscle CSA < 20%) based on whole thigh muscle CSA hypertrophy. Whole thigh muscle and knee extensors CSAs were significantly greater (P < 0.0001) in high-responders (29 ± 7% and 47 ± 15%, respectively) compared to low-responders (12 ± 3% and 19 ± 6%, respectively). There were no differences in total caloric intake or macronutrient intake between groups. Extensor spasticity was lower in the high-responders compared to the low-responders as was the dosage of baclofen. Prior to the intervention, the high-responders had greater body mass compared to the low-responders with SCI (87.8 ± 13.7 vs. 70.4 ± 15.8 kg; P = 0.012), body mass index (BMI: 27.6 ± 2.7 vs. 22.9 ± 6.0 kg/m2; P = 0.04), as well as greater percentage in whole body and regional fat mass (P < 0.05). Furthermore, high-responders had a 69% greater increase (P = 0.086) in total Akt protein expression than low-responders. High-responders also exhibited reduced circulating IGF-1 with a concomitant increase in IGFBP-3. Exploratory analyses revealed upregulation of mRNAs for muscle hypertrophy markers [IRS-1, Akt, mTOR] and downregulation of protein degradation markers [myostatin, MurF-1, and PDK4] in the high-responders compared to low-responders. The findings indicate that body composition, spasticity, baclofen usage, and multiple signaling pathways (anabolic and catabolic) are involved in the differential muscle hypertrophy response to NMES-RT in persons with chronic SCI.

The impact of rehabilitation in bone loss management of patients with spinal cord injury: A systematic review

BACKGROUND

Spinal cord injury (SCI) is a disabling condition characterized by multilevel skeletal muscle impairment and rapid cortical and trabecular bone loss. Rehabilitation is a cornerstone of the long-term management of patients with SCI; however, the optimal rehabilitation strategy for improving bone health has not been fully characterized.

OBJECTIVE

To characterize the current evidence supporting different rehabilitation interventions improving bone health in patients with SCI.

METHODS

On November 17th, 2022, five databases (PubMed, Scopus, Web of Science, Cochrane, and PEDro) were systematically searched for randomized controlled trials (RCTs) assessing SCI patients undergoing rehabilitation interventions. The primary outcomes were bone macroscopical effects. Secondary outcomes were changes in bone metabolisms and functional outcomes.

RESULTS

Out of 499 records, 11 RCTs met the eligibility criteria and were included. Electrical stimulation combined with physical exercise was assessed by 5 studies, standing intervention was assessed by 3 studies, vibration was assessed by 1 study, ultrasound therapy was assessed by 1 study, and electroacupuncture combined with a pulsed magnetic field was assessed by 1 study. The rehabilitation intervention was administered combined with pharmacological treatment (3 studies) or alone (8 studies). Positive effects in terms of BMD were reported by 3 studies. The quality assessment revealed some concerns in 9 out of 11 studies, in accordance with the Cochrane Risk of Bias assessment - version 2.

CONCLUSION

Our data suggest that multicomponent interventions including rehabilitation might be considered a suitable option to improve bone health management in SCI patients. Further studies are mandatory to characterize the optimal combination of non-pharmacological interventions reducing bone loss and improving the risk of fractures in patients with SCI.

A Systematic Review of Testosterone Therapy in Men With Spinal Cord Injury or Traumatic Brain Injury

Spinal cord injuries (SCI) and traumatic brain injuries (TBI) increase the risk of testosterone deficiency and result in adverse changes in body composition and poor functional outcomes. The current systematic review aims to provide insights into the use of testosterone therapy for treating men with SCI and TBI. The PubMed and EMBASE databases were systematically reviewed using appropriate terms, and resulting manuscripts were screened using defined Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The patient population included male patients with SCI or TBI. Further inclusion criteria were: a) human participants 18 years of age or older; b) manuscript published in English; c) study included an intervention with exogenous testosterone; and d) articles published in peer-reviewed journals with full text available. Two reviewers independently extracted data regarding injury type, intervention, and outcomes. Following screening for inclusion/exclusion criteria, a total of 12 primary research studies conducted over the last 30 years were included. Men with SCI were investigated in 11 articles. The combination of testosterone patches and resistance training with functional electrical stimulation (FES) for 16 weeks in men with SCI and an average baseline testosterone level above the cutoff for testosterone deficiency increased muscle mass, strength, bone quality, and basal metabolic rate while testosterone patches without exercise for 16 weeks produced no significant changes in these parameters. Testosterone patches for 12 months in men with SCI and testosterone deficiency also increased lean tissue mass (LTM) and resting energy expenditure (REE). In one study, men with TBI and testosterone deficiency receiving testosterone gel for eight weeks showed a non-statistically significant greater absolute change in functional independence measure (FIM) and grip strength compared to a placebo group. Testosterone therapy with exercise may help improve muscle mass, bone health, strength, energy expenditure, and cardiac health in men with SCI without major side effects. It is difficult to draw conclusions regarding the effects of testosterone therapy in men with TBI based on the limited available evidence. Further investigation is warranted to explore the relationship between testosterone therapy and recovery after SCI and TBI.

Promising Advances in Pharmacotherapy for Patients with Spinal Cord Injury-A Review of Studies Performed In Vivo with Modern Drugs

Spinal cord injury (SCI) is a pathological neurological condition that leads to significant motor dysfunction. It is a condition that occurs as a result of tragic accidents, violent acts, or as a consequence of chronic diseases or degenerative changes. The current treatments for patients with SCI have moderate efficacy. They improve the quality of life of patients, but they are still doomed to long-term disability. In response to the modern directions of research on possible therapeutic methods that allow for the recovery of patients with SCI, a scientific review publication is needed to summarize the recent developments in this topic. The following review is focused on the available pharmacological treatments for SCIs and the problems that patients face depending on the location of the injury. In the following review, the research team describes problems related to spasticity and neuropathic pain; possible therapeutic pathways are also described for neuroprotection and the improvement of neurotransmission within the injured spinal cord, and the review focuses on issues related to oxidative stress.

Employment of Neuromuscular Electrical Stimulation to Examine Muscle and Bone Qualities after Spinal Cord Injury

(1) Background: Resource intensive imaging tools have been employed to examine muscle and bone qualities after spinal cord injury (SCI). We tested the hypothesis that surface neuromuscular electrical stimulation (NMES) amplitude can be used to examine knee extensor muscle quality, distal femur and proximal tibia bone mineral density (BMD) in persons with SCI. (2) Methods: Seventeen persons (2 women) with chronic SCI participated in three weeks of NMES-resistance training twice weekly of 4 sets of 10 repetitions. Participants were classified according to the current amplitude (>100 mA) and the number of repetitions (>70 reps) of leg extension into greater (n = 8; 1 woman; group A) and lower (n = 9; 1 woman; group B) musculoskeletal qualities. Magnetic resonance imaging, dual energy x-ray absorptiometry, isometric peak torque, Modified Ashworth and Penn spasm frequency scales were conducted. (3) Results: In between group comparisons, current amplitude was lower (38−46%) in group A. Whole (27−32%; p = 0.02), absolute (26−33%, p = 0.02) thigh muscle and absolute knee extensor muscle cross-sectional areas (22−33%, p = 0.04) were greater in group A. Right distal femur (24%; p = 0.08) and proximal tibia (29%; p = 0.03) BMDs were lower in group B, and peak isometric torque (p < 0.01), extensor spasticity scorers (p = 0.04) and muscle spasm scores (p = 0.002) were significantly higher in group A. Regression models revealed that amplitude of current, repetitions and body weight can accurately predict musculoskeletal qualities in persons with SCI. (4) Conclusions: Surface NMES amplitude and repetitions of leg extension differentiated between SCI survivors with greater versus lower musculoskeletal qualities. The study may shed the light on the interplay between muscle and bone in persons with SCI.

Early Changes in Androgen Levels in Individuals with Spinal Cord Injury: A Longitudinal SwiSCI Study

We aimed to explore longitudinal changes in androgen levels in individuals with spinal cord injury (SCI) within initial inpatient rehabilitation stay and identify clinical/injury characteristics associated with hormone levels. Linear regression analysis was applied to explore the association between personal/injury characteristics and androgen hormones (total testosterone, free testosterone, sex hormone-binding globulin (SHBG), dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEA-S)) at admission to rehabilitation. Longitudinal changes in androgen levels were studied using linear mixed models. Analyses were stratified by sex and by injury type. We included 70 men and 16 women with SCI. We observed a non-linear association between age, time since injury, and androgens at baseline. At admission to initial rehabilitation, mature serum SHBG (full-length, protein form which lacks the N-terminal signaling peptide) was higher, while DHEA and DHEA-S were lower among opioid users vs. non-users. Serum levels of total testosterone and DHEA-S increased over rehabilitation period [β 3.96 (95%CI 1.37, 6.56), p = 0.003] and [β 1.77 (95%CI 0.73, 2.81), p = 0.01], respectively. We observed no significant changes in other androgens. Restricting our analysis to men with traumatic injury did not materially change our findings. During first inpatient rehabilitation over a median follow up of 5.6 months, we observed an increase in total testosterone and DHEA-S in men with SCI. Future studies need to explore whether these hormonal changes influence neurological and functional recovery as well as metabolic parameters during initial rehabilitation stay.

Prediction of Distal Femur and Proximal Tibia Bone Mineral Density From Total Body Dual Energy X-Ray Absorptiometry Scans in Persons with Spinal Cord Injury

Bone density decreases rapidly after spinal cord injury (SCI), increasing fracture risk. The most common fracture sites are at the knee (i.e., distal femur or proximal tibia). Despite this high fracture incidence, knee-specific scans for bone density using dual x-ray absorptiometry (DXA) were not available until 2014 and are still not routinely used in clinical practice today. This has made it difficult to determine the rehabilitation efficacy and hindered understanding of the long-term changes in knee areal bone density. The purpose of this investigation was to compare areal bone mineral density values for the knee from both total-body and knee-specific DXA scans in persons with SCI. A total of 20 participants (16 males) >1 yr-post spinal cord injury received two DXA scans; a total-body scan and a knee-specific scan. Standardized methods were used to create regions of interest to determine bone density of four regions - the epiphysis and metaphysis of the distal femur and proximal tibia - from the total-body scan. Linear regressions and Bland-Altman analyses were conducted to determine the correlation (r²) and agreement (mean bias ± 95% level of agreement) respectively between the two scan types for each region. Linear regression analyses showed strong significant (p < 0.001) relationships between the two scan types for the distal femur epiphysis (r² = 0.88) and metaphysis (r² = 0.98) and the proximal tibia epiphysis (r² = 0.88) and metaphysis (r² = 0.99). The mean bias ± 95% level of agreement were distal femur epiphysis (0.05 ± 0.1 g/cm²) and metaphysis (0.02 ± 0.04 g/cm²); proximal tibia epiphysis (-0.02 ± 0.1 g/cm²) and metaphysis (0.02 ± 0.03 g/cm²). Results suggest knee-specific bone density can be assessed using a total-body DXA scan. This may allow for more comprehensive use of DXA scans which would reduce the burden of multiple site-specific scans for persons with SCI and enable more widespread adoption of knee bone density assessment in this population.

The Effects of Exercise and Activity-Based Physical Therapy on Bone after Spinal Cord Injury

Spinal cord injury (SCI) produces paralysis and a unique form of neurogenic disuse osteoporosis that dramatically increases fracture risk at the distal femur and proximal tibia. This bone loss is driven by heightened bone resorption and near-absent bone formation during the acute post-SCI recovery phase and by a more traditional high-turnover osteopenia that emerges more chronically, which is likely influenced by the continual neural impairment and musculoskeletal unloading. These observations have stimulated interest in specialized exercise or activity-based physical therapy (ABPT) modalities (e.g., neuromuscular or functional electrical stimulation cycling, rowing, or resistance training, as well as other standing, walking, or partial weight-bearing interventions) that reload the paralyzed limbs and promote muscle recovery and use-dependent neuroplasticity. However, only sparse and relatively inconsistent evidence supports the ability of these physical rehabilitation regimens to influence bone metabolism or to increase bone mineral density (BMD) at the most fracture-prone sites in persons with severe SCI. This review discusses the pathophysiology and cellular/molecular mechanisms that influence bone loss after SCI, describes studies evaluating bone turnover and BMD responses to ABPTs during acute versus chronic SCI, identifies factors that may impact the bone responses to ABPT, and provides recommendations to optimize ABPTs for bone recovery.