Metabolic and endocrine changes in persons aging with spinal cord injury

Distinct Genomic Expression Signatures after Low-Force Electrically Induced Exercises in Persons with Spinal Cord Injury

People with a spinal cord injury are at an increased risk of metabolic dysfunction due to skeletal muscle atrophy and the transition of paralyzed muscle to a glycolytic, insulin-resistant phenotype. Providing doses of exercise through electrical muscle stimulation may provide a therapeutic intervention to help restore metabolic function for people with a spinal cord injury, but high-frequency and high-force electrically induced muscle contractions increase fracture risk for the underlying osteoporotic skeletal system. Therefore, we investigated the acute molecular responses after a session of either a 3 Hz or 1 Hz electrically induced exercise program. Ten people with a complete spinal cord injury completed a 1 h (3 Hz) or 3 h (1 Hz) unilateral electrically induced exercise session prior to a skeletal muscle biopsy of the vastus lateralis. The number of pulses was held constant. Tissue samples were analyzed for genomic and epigenomic expression profiles. There was a strong acute response after the 3 Hz exercise leading to the upregulation of early response genes (NR4A3, PGC-1α, ABRA, IRS2, EGR1, ANKRD1, and MYC), which have prominent roles in regulating molecular pathways that control mitochondrial biogenesis, contractile protein synthesis, and metabolism. Additionally, these genes, and others, contributed to the enrichment of pathways associated with signal transduction, cellular response to stimuli, gene expression, and metabolism. While there were similar trends observed after the 1 Hz exercise, the magnitude of gene expression changes did not reach our significance thresholds, despite a constant number of stimuli delivered. There were also no robust acute changes in muscle methylation after either form of exercise. Taken together, this study supports that a dose of low-force electrically induced exercise for 1 h using a 3 Hz stimulation frequency is suitable to trigger an acute genomic response in people with chronic paralysis, consistent with an expression signature thought to improve the metabolic and contractile phenotype of paralyzed muscle, if performed on a regular basis.

Ergogenic effects of spinal cord stimulation on exercise performance following spinal cord injury

Cervical or upper-thoracic spinal cord injury (SCI, ≥T6) often leads to low resting blood pressure (BP) and impaired cardiovascular responses to acute exercise due to disrupted supraspinal sympathetic drive. Epidural spinal cord stimulation (invasive, ESCS) and transcutaneous spinal cord stimulation (non-invasive, TSCS) have previously been used to target dormant sympathetic circuits and modulate cardiovascular responses. This case series compared the effects of cardiovascular-optimised ESCS and TSCS versus sham ESCS and TSCS on modulating cardiovascular responses and improving submaximal upper-body exercise performance in individuals with SCI. Seven males with a chronic, motor-complete SCI between C6 and T4 underwent a mapping session to identify cardiovascular responses to spinal cord stimulation. Subsequently, four participants (two ESCS and two TSCS) completed submaximal exercise testing. Stimulation parameters (waveform, frequency, intensity, epidural electrode array configuration, and transcutaneous electrode locations in the lumbosacral region) were optimised to elevate cardiovascular responses (CV-SCS). A sham condition (SHAM-SCS) served as a comparison. Participants performed arm-crank exercise to exhaustion at a fixed workload corresponding to above ventilatory threshold, on separate days, with CV-SCS or SHAM-SCS. At rest, CV-SCS increased BP and predicted left ventricular cardiac contractility and total peripheral resistance. During exercise, CV-SCS increased time to exhaustion and peak oxygen pulse (a surrogate for stroke volume), relative to SHAM-SCS. Ratings of perceived exertion also tended to be lower with CV-SCS than SHAM-SCS. Comparable improvements in time to exhaustion with ESCS and TSCS suggest that both approaches could be promising ergogenic aids to support exercise performance or rehabilitation, along with reducing fatigue during activities of daily living in individuals with SCI.

Spinal Cord Injury Associated Disease of the Skeleton, an Unresolved Problem with Need for Multimodal Interventions

Spinal cord injury is associated with skeletal unloading, sedentary behavior, decreases in skeletal muscle mass, and exercise intolerance, which results in rapid and severe bone loss. To date, monotherapy with physical interventions such as weight-bearing in standing frames, computer-controlled electrically stimulated cycling and ambulation exercise, and low-intensity vibration are unsuccessful in maintaining bone density after SCI. Strategies to maintain bone density with commonly used osteoporosis medications also fail to provide a significant clinical benefit, potentially due to a unique pathology of bone deterioration in SCI. In this review, the available data is discussed on evaluating and monitoring bone loss, fracture, and physical and pharmacological therapeutic approaches to SCI-associated disease of the skeleton. The treatment of SCI-associated disease of the skeleton, the implications for clinical management, and areas of need are considered for future investigation.

Validation of basal metabolic rate equations in persons with innervated and denervated chronic spinal cord injury

Basal metabolic rate (BMR) measurement is time consuming and requires specialized equipment. Prediction equations allow clinicians and researchers to estimate BMR; however, their accuracy may vary across individuals with chronic spinal cord injury (SCI). The objective of this study was to investigate the validity of SCI-specific equations as well as able-bodied (AB) prediction equations in individuals with upper motor neuron (UMN), lower motor neuron (LMN), and females with SCI. Twenty-six men and women with chronic SCI (n = 12 innervated males, n = 6 innervated females, n = 8 denervated males) participated in this cross-sectional study. BMR values were measured by indirect calorimetry. Body composition (dual-energy X-ray absorptiometry and anthropometrics) assessment was conducted. AB-prediction equations [Cunningham, Nelson, Owen, Harris and Benedict, Mifflin, Schofield, Henry] and SCI-specific equations [Chun and Nightingale & Gorgey] were used to estimate and validate BMR. The accuracy of AB-specific FFM equations in predicting BMR was evaluated using Bland-Altman plots, paired t-tests, and error metrics. Measured BMR for innervated males, females, and denervated males was 1436 ± 213 kcal/day, 1290 ± 114, and 1597 ± 333 kcal/day, respectively. SCI-specific equations by Chun et al., Nightingale & Gorgey, and AB-specific FFM equations accurately predicted BMR for innervated males. For the denervated males, Model 4 equation by Nightingale & Gorgey was not different (p = 0.18), and Bland-Altman analyses showed negative mean bias but similar limits of agreement between measured and predicted BMR for the SCI-specific equations and AB-specific FFM equations. We demonstrated that SCI-specific equations accurately predicted BMR for innervated males but underpredicted it for denervated males. The Model 4 equation by Nightingale & Gorgey accurately estimated BMR in females with SCI. Findings from the current study will help to determine caloric needs in different sub-groups of SCI.

Bioactive role of vitamins as a key modulator of oxidative stress, cellular damage and comorbidities associated with spinal cord injury (SCI)

Introduction: Spinal cord injury (SCI) cause significant disability and impact the quality of life of those affected by it. The nutritional status and diet are fundamental to diminish the progression of complications; vitamins modulate the inflammatory response and oxidative stress, promote blood-spinal cord barrier preservation and the prompt recovery of homeostasis. A deep knowledge of the benefits achieved from vitamins in patients with SCI are summarized. Information of dosage, time, and effects of vitamins in these patients are also displayed. Vitamins have been extensively investigated; however, more clinical trials are needed to clarify the scope of vitamin supplementation.Objective: The objective of this review was to offer relevant therapeutic information based on vitamins supplementation for SCI patients.Methods: Basic and clinical studies that have implemented the use of vitamins in SCI were considered. They were selected from the year 2000-2022 from three databases: PubMed, Science Direct and Google Scholar.Results: Consistent benefits in clinical trials were shown in those who were supplemented with vitamin D (prevents osteoporosis and improves physical performance variables), B3 (improves lipid profile) and B12 (neurological prophylaxis of chronic SCI damage) mainly. On the other hand, improvement related to neuroprotection, damage modulation (vitamin A) and its prophylaxis were associated to B complex vitamins supplementation; the studies who reported positive results are displayed in this review.Discussion: Physicians should become familiar with relevant information that can support conventional treatment in patients with SCI, such as the use of vitamins, a viable option that can improve outcomes in patients with this condition.

Salsalate Improves Postprandial Glycemic and Some Lipid Responses in Persons With Tetraplegia: A Randomized Clinical Pilot Trial With Crossover Design

Objectives

To investigate the effects of salsalate on fasting and postprandial (PP) glycemic, lipidemic, and inflammatory responses in persons with tetraplegia.

Methods

This study was a randomized, double-blind, cross-over design. It was conducted at a university laboratory. Ten males aged 25 to 50 years with SCI at C5-8 levels for ≥1 year underwent 1 month of placebo and salsalate (4 g/day) treatment. Blood samples were drawn before and 4 hours after breakfast and lunch fast-food meal consumption.

Results

Descriptive statistics indicate that fasting and PP glucose values were reduced with salsalate (pre-post mean difference, 4 ± 5 mg/dL and 8 ± 8 mg/dL, respectively) but largely unchanged with placebo (0 ± 6 mg/dL and -0 ± 7 mg/dL, respectively). Insulin responses were generally reciprocal to glucose, however less pronounced. Fasting free fatty acids were significantly reduced with salsalate (191 ± 216 mg/dL, p = .021) but not placebo (-46 ± 116 mg/dL, p = .878). Results for triglycerides were similar (25 ± 34 mg/dL, p =.045, and 7 ± 29 mg/dL, p = .464). Fasting low-density lipoprotein (LDL) levels were higher after salsalate (-10 ± 12 mg/dL, p = .025) but not placebo (2 ± 9 mg/dL, p = .403) treatment. Inflammatory markers were largely unchanged.

Conclusion

In this pilot trial, descriptive values indicate that salsalate decreased fasting and PP glucose response to fast-food meal challenge at regular intervals in persons with tetraplegia. Positive effects were also seen for some lipid but not for inflammatory response markers. Given the relatively "healthy" metabolic profiles of the participants, it is possible that salsalate's effects may be greater and more consistent in people with less favorable metabolic milieus.

Diagnosis and Management of Cardiovascular Risk in Individuals With Spinal Cord Injury: A Narrative Review

More than 16 000 Americans experience spinal cord injury (SCI), resulting in chronic disability and other secondary sequelae, each year. Improvements in acute medical management have increased life expectancy. Cardiovascular disease is a leading cause of death in this population, and seems to occur earlier in individuals with SCI compared with the general population. People with SCI experience a high burden of traditional cardiovascular disease risk factors, including dyslipidemia and diabetes, and demonstrate anatomic, metabolic, and physiologic changes alongside stark reductions in physical activity after injury. They also experience multiple, complex barriers to care relating to disability and, in many cases, compounding effects of intersecting racial and socioeconomic health inequities. Given this combination of risk factors, some investigators have proposed that people with SCI are at increased risk for cardiovascular disease, beyond that associated with traditional risk factors, and SCI could be considered a risk-enhancing factor, analogous to other risk-enhancing factors defined by the 2019 American Heart Association/American College of Cardiology Primary Prevention Guidelines. However, more research is needed in this population to clarify the role of traditional risk factors, novel risk factors, health care access, social determinants of health, and intersectionality of disability, race, and socioeconomic status. There is an urgent need for primary care physicians and cardiologists to have awareness of the importance of timely diagnosis and management of cardiac risk factors for people with SCI.

Acute changes in antioxidants and oxidative stress to vigorous arm exercise: an intervention trial in persons with spinal cord injury and healthy controls

STUDY DESIGN

Intervention trial.

BACKGROUND

Literature remains unclear on possible health benefits and risks assosciated with high intensity exercise for persons with SCI. Elevated oxidative stress levels might influence their ability to exercise at high intensity. We investigated several biomarkers of oxidative stress and antioxidant defense at rest, during and after vigorous exercise among persons with chronic SCI.

SETTING

Sunnaas Rehabilitation Hospital, Norway.

METHODS

Six participants (five males) with chronic SCI (AIS A, injury level thoracic 2-8, >1 year postinjury) and six matched able-bodied controls performed two maximal arm-cranking tests, with one-three days in between. During the second exercise test, participants performed three bouts with four minutes arm cranking at high intensity (85-95% of peak heart rate (HR_peak)), before they reached maximal effort. Blood and urine biomarkers for oxidative stress and antioxidant levels were collected at six time points at the day of the second exercise test; baseline, at high intensity exercise, at maximal effort, at five, 30 and 60 min post-exercise, and 24 h post exercise.

RESULTS

Participants with SCI had significant lower levels of creatinine (∆16 µmol/L, p = 0.03), α-carotene (∆0.14 nmol/L, p < 0.001) and β-carotene (∆0.51 nmol/L, p = 0.001) at baseline compared to controls. Urine and blood biomarkers of oxidative stress and antioxidant levels showed similar response to vigorous exercise in the SCI and control group.

CONCLUSIONS

SCI participants showed similar changes in redox status during high intensity exercise compared to matched able-bodied. SCI participants had lower levels of exogen antioxidants both before, during and after vigorous exercise.

Propulsion kinetics of recumbent handcycling during high and moderate intensity exercise

People with spinal cord injuries (PwSCI) are at high risk of developing cardiovascular disease (CVD). While regular exercise can reduce risk of CVD, PwSCI face various barriers to exercise, including high rates of upper limb injuries, especially in the shoulder. Handcycling high intensity interval training (HIIT), which consists of periods of high intensity exercise followed by rest, is a potential exercise solution, but the musculoskeletal safety of HIIT is still unknown. In this study, we characterized three-dimensional continuous applied forces at the handle during handcycling HIIT and moderate intensity continuous training (MICT). These applied forces can give an early indication of joint loading, and therefore injury risk, at the shoulder. In all three directions (tangential, radial, and lateral), the maximum applied forces during HIIT were larger than those in MICT at all timepoints, which may indicate higher contact forces and loads on the shoulder during HIIT compared to MICT. The tangential and radial forces peaked twice in a propulsion cycle, while the lateral forces peaked once. Throughout the exercises, the location of tangential peak 2 and radial peak 1 was later in HIIT compared to MICT. This difference in maximum force location could indicate either altered kinematics or muscular fatigue at the end of the exercise protocol. These changes in kinematics should be more closely examined using motion capture or other modeling techniques. If we combine this kinetic data with kinematic data during propulsion, we can create musculoskeletal models that more accurately predict contact forces and injury risk during handcycling HIIT in PwSCI.

Consequences of spinal cord injury on the sympathetic nervous system

Spinal cord injury (SCI) damages multiple structures at the lesion site, including ascending, descending, and propriospinal axons; interrupting the conduction of information up and down the spinal cord. Additionally, axons associated with the autonomic nervous system that control involuntary physiological functions course through the spinal cord. Moreover, sympathetic, and parasympathetic preganglionic neurons reside in the spinal cord. Thus, depending on the level of an SCI, autonomic function can be greatly impacted by the trauma resulting in dysfunction of various organs. For example, SCI can lead to dysregulation of a variety of organs, such as the pineal gland, the heart and vasculature, lungs, spleen, kidneys, and bladder. Indeed, it is becoming more apparent that many disorders that negatively affect quality-of-life for SCI individuals have a basis in dysregulation of the sympathetic nervous system. Here, we will review how SCI impacts the sympathetic nervous system and how that negatively impacts target organs that receive sympathetic innervation. A deeper understanding of this may offer potential therapeutic insight into how to improve health and quality-of-life for those living with SCI.

Factors associated with sports participation amongst people with spinal cord injury in a Malaysian tertiary hospital

OBJECTIVE

To identify factors that are associated with sports participation following spinal cord injury (SCI).

STUDY DESIGN

Case-control study.

SETTING

Spinal Rehabilitation outpatient clinic in a tertiary hospital in Kuala Lumpur, Malaysia.

PARTICIPANTS

Thirty-one sports participants (SP) and thirty-four non-sports participants (NSP) (N = 65) met the following inclusion criteria; chronic SCI more than one year, age between 18 and 50 years, both traumatic and non-traumatic SCI at C5 level and below, complete or incomplete SCI (AIS A-D) and mobilizing with either manual or motorized wheelchair independently.

METHODS

Face-to-face interviews were performed with a 22-item self-constructed questionnaire which contained four domains of variables; socio-demographic, SCI-related, environmental and sports-related factors. Data collection was done between June 2017 and May 2018.

RESULTS

Traumatic SCI, pre-injury interest in sports, pre-injury sports participation, ability to drive own vehicles, and being employed were significantly associated with sports participation post-SCI (p < 0.05). Multiple logistic regression revealed traumatic SCI (p = 0.012, OR 34.70, CI 2.21-545.90) and pre-injury interest in sports (p = 0.046, OR 29.10, CI 1.06-798.95) to be independent predictors of sports participation post-SCI.

CONCLUSION

Traumatic SCI and pre-injury interest in sports were predictors of sports participation post-SCI. Pre-injury sports participation, being employed, and the ability to drive own vehicles were positively associated with sports participation. Findings from this study suggest a few crucial differences in facilitators and barriers to sports participation in Malaysia compared to other countries.

Acute Low Force Electrically Induced Exercise Modulates Post Prandial Glycemic Markers in People with Spinal Cord Injury

Regular exercise involves daily muscle contractions helping metabolize up to 70% of daily ingested glucose. Skeletal muscle increases glucose uptake through two distinct pathways: insulin signaling pathway and muscle contraction mediated AMPK pathway. People with paralysis are unable to contract their muscles which atrophy, transform into insulin resistant glycolytic muscle, and develop osteoporosis. Our goal is to determine if low force electrically induced exercise (LFE) will modulate the post prandial insulin and glucose response in people with and without spinal cord injury (SCI). 18 people with SCI and 23 without SCI (Non-SCI) participated in an assessment of metabolic biomarkers during passive sitting (CTL) and a bout of LFE delivered to the quadriceps/hamstring muscle groups after a glucose challenge. Baseline fasting insulin (p = 0.003) and lactate (p = 0.033) levels were higher in people with SCI, but glucose levels (p = 0.888) were similar compared to the non-SCI population. After 1-h of muscle contractions using LFE, heart rate increased (p < 0.001), capillary glucose decreased (p = 0.004), insulin decreased (p < 0.001), and lactate increased (p = 0.001) in the SCI population. These findings support that LFE attenuates certain metabolic blood biomarkers during a glucose challenge and may offer a lifestyle strategy to regulate metabolic responses after eating among people with SCI.

Metabolic and cardiopulmonary impact of aquatic exercise and nutritional guidance for four individuals with chronic motor incomplete spinal cord injury: a case series

BACKGROUND

Persons living with chronic spinal cord injury (SCI) demonstrate an increased risk of cardiovascular diseases.

Purpose The aim of this report was to assess the cardiopulmonary and metabolic impact of prescribed aquatic exercise in combination with dietary guidance for four individuals experiencing chronic SCI.

CASE DESCRIPTION

We measured peak oxygen consumption (peak VO₂), resting energy expenditure (REE), weight, food logs, fasting glucose, insulin and glycated hemoglobin (HbA1C) in four men with incomplete SCI, aged 34 to 63 years.

INTERVENTION

The men received a group aquatic exercise program three times per week for 10 weeks, and a weekly individual nutritional consultation by phone.

OUTCOMES

Peak VO₂ increased by 7.9% and 34.4% in participants #3 and #4 and decreased by 12% and 16.4% in #1 and #2. Glucose values decreased by 19.6% and 14.2% for #1 and #3, and increased by 9.3% for both #2 and #4. Body mass decreased by 9.9%, 3.0% and 5.7% for participants #1, #2 and #3, but demonstrated no change for participant #4. Dietary guidance and education produced positive changes, including reduced fat, carbohydrate, daily sugar, and average calorie intake.

CONCLUSION

Moderate exercise with weekly nutritional guidance appeared to positively impact body mass and dietary selections with varied metabolic and cardiopulmonary results.

Is Sleep Disordered Breathing Confounding Rehabilitation Outcomes in Spinal Cord Injury Research?

The purpose of this article is to highlight the importance of considering sleep-disordered breathing (SDB) as a potential confounder to rehabilitation research interventions in spinal cord injury (SCI). SDB is highly prevalent in SCI, with increased prevalence in individuals with higher and more severe lesions, and the criterion standard treatment with continuous positive airway pressure remains problematic. Despite its high prevalence, SDB is often untested and untreated in individuals with SCI. In individuals without SCI, SDB is known to negatively affect physical function and many of the physiological systems that negatively affect physical rehabilitation in SCI. Thus, owing to the high prevalence, under testing, low treatment adherence, and known negative effect on the physical function, it is contended that underdiagnosed SDB in SCI may be confounding physical rehabilitation research studies in individuals with SCI. Studies investigating the effect of treating SDB and its effect on physical rehabilitation in SCI were unable to be located. Thus, studies investigating the likely integrated relationship among physical rehabilitation, SDB, and proper treatment of SDB in SCI are needed. Owing to rapid growth in both sleep medicine and physical rehabilitation intervention research in SCI, the authors contend it is the appropriate time to begin the conversations and collaborations between these fields. We discuss a general overview of SDB and physical training modalities, as well as how SDB could be affecting these studies.

Functional electrical stimulation-assisted cycle ergometry-based progressive mobility programme for mechanically ventilated patients: randomised controlled trial with 6 months follow-up

PURPOSE

Functional electrical stimulation-assisted cycle ergometry (FESCE) enables in-bed leg exercise independently of patients' volition. We hypothesised that early use of FESCE-based progressive mobility programme improves physical function in survivors of critical care after 6 months.

METHODS

We enrolled mechanically ventilated adults estimated to need >7 days of intensive care unit (ICU) stay into an assessor-blinded single centre randomised controlled trial to receive either FESCE-based protocolised or standard rehabilitation that continued up to day 28 or ICU discharge.

RESULTS

We randomised in 1:1 ratio 150 patients (age 61±15 years, Acute Physiology and Chronic Health Evaluation II 21±7) at a median of 21 (IQR 19-43) hours after admission to ICU. Mean rehabilitation duration of rehabilitation delivered to intervention versus control group was 82 (IQR 66-97) versus 53 (IQR 50-57) min per treatment day, p<0.001. At 6 months 42 (56%) and 46 (61%) patients in interventional and control groups, respectively, were alive and available to follow-up (81.5% of prespecified sample size). Their Physical Component Summary of SF-36 (primary outcome) was not different at 6 months (50 (IQR 21-69) vs 49 (IQR 26-77); p=0.26). At ICU discharge, there were no differences in the ICU length of stay, functional performance, rectus femoris cross-sectional diameter or muscle power despite the daily nitrogen balance was being 0.6 (95% CI 0.2 to 1.0; p=0.004) gN/m2 less negative in the intervention group.

CONCLUSION

Early delivery of FESCE-based protocolised rehabilitation to ICU patients does not improve physical functioning at 6 months in survivors.

TRIAL REGISTRATION NUMBER

NCT02864745.

The use of simple muscle strength tests to reflect body compositions among individuals with spinal cord injury

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

To investigate the correlation between simple muscle strength tests (including handgrip test and upper limb loading during a seated push-up test [ULL-SPUT]) and body compositions among individuals with spinal cord injury (SCI).

SETTING

A tertiary rehabilitation center.

METHODS

Twenty-four participants with SCI (average age of 40 years) were cross-sectionally assessed using handgrip test, ULL-SPUT, and body compositions (including skeletal muscle mass, bone mineral content, and fat mass) using dual-energy X-ray absorptiometry scan.

RESULTS

The handgrip data had low-to-moderate correlation to body compositions of the arms (r_s = 0.474-0.515, p < 0.05), while the ULL-SPUT data were low-to-excellently correlated to all body compositions of the arms, legs, and trunk (r_s, r = 0.467-0.921, p < 0.05).

CONCLUSIONS

The findings extend clinical benefit of a SPUT apart from being a rehabilitation strategy to promote mobility of individuals with SCI. Simple measurement of the ULL-SPUT, which can be done using digital bathroom scales placed on a hard and even surface, appears to be strongly correlated with body compositions in a small sample of predominantly middle age, normal weight, men with paraplegia. More research is required to understand whether this test can be used clinically to assess body compositions in a more diverse SCI population, and whether it is responsive to changes in body compositions over time.

Feasibility of an Internet-Based Intervention to Promote Exercise for People With Spinal Cord Injury: Observational Pilot Study

BACKGROUND

People with spinal cord injury (SCI) are less likely to be physically active and have higher chronic disease risk than those in the general population due to physical and metabolic changes that occur postinjury. Few studies have investigated approaches to promote increased physical activity (PA) for people with SCI despite evidence that they face unique barriers, including lack of accessible transportation and exercise equipment. To address these obstacles, we adapted an evidence-based phone-delivered intervention that promoted increased PA among people with SCI into a web-based platform, titled the Workout on Wheels internet intervention (WOWii). The adapted program provides participants with weekly skill-building information and activities, basic exercise equipment, and ongoing support through weekly group videoconferencing.

OBJECTIVE

This pilot study was conducted to assess the feasibility of using a web-based and virtual format to deliver the WOWii program in a randomized controlled trial.

METHODS

We assessed the feasibility of the web-based program by delivering an abbreviated, 4-week version to 10 participants with SCI. Rates of weekly videoconference attendance, activity completion, and exercise activity as tracked by an arm-based activity monitor were recorded for all participants.

RESULTS

Participants averaged 3.3 of 4 (83%) weekly group videoconferences attended, 3.4 of 4 (85%) web-based module activities completed, and 2.3 of 4 (58%) weeks of using the arm-based activity monitor. The majority of the sample (9/10, 90%) synced their arm-based PA monitor at least once, and overall engagement as an average of each component across the 4 weeks was 75%.

CONCLUSIONS

The intervention had sufficiently high levels of engagement to be used in a full randomized controlled trial to test its effectiveness in improving levels of PA among people with SCI. The knowledge we gained from this pilot study informed improvements that were made in the full randomized controlled trial.

Metabolic Dysfunction in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder leading to paralysis, muscle atrophy, and death. Significant advances in antisense oligonucleotide treatment and gene therapy have made it possible for SMA patients to benefit from improvements in many aspects of the once devastating natural history of the disease. How the depletion of survival motor neuron (SMN) protein, the product of the gene implicated in the disease, leads to the consequent pathogenic changes remains unresolved. Over the past few years, evidence toward a potential contribution of gastrointestinal, metabolic, and endocrine defects to disease phenotype has surfaced. These findings ranged from disrupted body composition, gastrointestinal tract, fatty acid, glucose, amino acid, and hormonal regulation. Together, these changes could have a meaningful clinical impact on disease traits. However, it is currently unclear whether these findings are secondary to widespread denervation or unique to the SMA phenotype. This review provides an in-depth account of metabolism-related research available to date, with a discussion of unique features compared to other motor neuron and related disorders.

Neurogenic Obesity and Skeletal Pathology in Spinal Cord Injury

Spinal cord injury (SCI) results in dramatic changes in body composition, with lean mass decreasing and fat mass increasing in specific regions that have important cardiometabolic implications. Accordingly, the recent Consortium for Spinal Cord Medicine (CSCM) released clinical practice guidelines for cardiometabolic disease (CMD) in SCI recommending the use of compartmental modeling of body composition to determine obesity in adults with SCI. This recommendation is guided by the fact that fat depots impact metabolic health differently, and in SCI adiposity increases around the viscera, skeletal muscle, and bone marrow. The contribution of skeletal muscle atrophy to decreased lean mass is self-evident, but the profound loss of bone is often less appreciated due to methodological considerations. General-population protocols for dual-energy x-ray absorptiometry (DXA) disregard assessment of the sites of greatest bone loss in SCI, but the International Society for Clinical Densitometry (ISCD) recently released an official position on the use of DXA to diagnose skeletal pathology in SCI. In this review, we discuss the recent guidelines regarding the evaluation and monitoring of obesity and bone loss in SCI. Then we consider the possible interactions of obesity and bone, including emerging evidence suggesting the possible influence of metabolic, autonomic, and endocrine function on bone health in SCI.

Exercise Interventions Targeting Obesity in Persons With Spinal Cord Injury

Spinal cord injury (SCI) results in an array of cardiometabolic complications, with obesity being the most common component risk of cardiometabolic disease (CMD) in this population. Recent Consortium for Spinal Cord Medicine Clinical Practice Guidelines for CMD in SCI recommend physical exercise as a primary treatment strategy for the management of CMD in SCI. However, the high prevalence of obesity in SCI and the pleiotropic nature of this body habitus warrant strategies for tailoring exercise to specifically target obesity. In general, exercise for obesity management should aim primarily to induce a negative energy balance and secondarily to increase the use of fat as a fuel source. In persons with SCI, reductions in the muscle mass that can be recruited during activity limit the capacity for exercise to induce a calorie deficit. Furthermore, the available musculature exhibits a decreased oxidative capacity, limiting the utilization of fat during exercise. These constraints must be considered when designing exercise interventions for obesity management in SCI. Certain forms of exercise have a greater therapeutic potential in this population partly due to impacts on metabolism during recovery from exercise and at rest. In this article, we propose that exercise for obesity in SCI should target large muscle groups and aim to induce hypertrophy to increase total energy expenditure response to training. Furthermore, although carbohydrate reliance will be high during activity, certain forms of exercise might induce meaningful postexercise shifts in the use of fat as a fuel. General activity in this population is important for many components of health, but low energy cost of daily activities and limitations in upper body volitional exercise mean that exercise interventions targeting utilization and hypertrophy of large muscle groups will likely be required for obesity management.

The Prevalence and Risk of Type 2 Diabetes in Adults with Disabilities in Korea

BACKGROUND

People with disabilities are at risk of secondary conditions such as diabetes. The aim of this study was to evaluate the prevalence and risk of type 2 diabetes in South Korea, especially among people with all types of disabilities.

METHODS

We conducted a cross-sectional study using data from the Korean National Health Insurance Service, with two disabilityfree controls matched for each participant with disabilities by age and sex. Information regarding the type, severity and grade of disabilities was obtained based on the National Disability Registry. Diagnosis of type 2 diabetes was defined according to the following criteria: presence of International Classification of Diseases, Tenth Revision, Clinical Modification codes E11, E12, E13, or E14 and claims for at least one oral anti-diabetic agent or insulin at baseline, or fasting glucose level ≥126 mg/dL.

RESULTS

We included 1,297,806 participants with disabilities and 2,943,719 control. Out of 4,241,525 participants, 841,990 (19.9%) were diagnosed with diabetes. The prevalence of diabetes was higher in the disability group compared with individuals without disabilities (23.1% vs. 18.4%). The odds of having diabetes was higher in the disability group compared with the control group (adjusted odds ratio, 1.34; 95% confidence interval, 1.33 to 1.34). The results showed higher prevalence of diabetes in the mildly disabled group (23.2%) than in the severely disabled group (22.7%).

CONCLUSION

The prevalence and risk of diabetes were higher in people with disabilities compared with the general population. Physicians and public health authorities should focus on people with disabilities for proper diabetes management.

Impact of short- and long-term electrically induced muscle exercise on gene signaling pathways, gene expression, and PGC1a methylation in men with spinal cord injury

Exercise attenuates the development of chronic noncommunicable diseases (NCDs). Gene signaling pathway analysis offers an opportunity to discover if electrically induced muscle exercise regulates key pathways among people living with spinal cord injury (SCI). We examined short-term and long-term durations of electrically induced skeletal muscle exercise on complex gene signaling pathways, specific gene regulation, and epigenetic tagging of PGC1a, a major transcription factor in skeletal muscle of men with SCI. After short- or long-term electrically induced exercise training, participants underwent biopsies of the trained and untrained muscles. RNA was hybridized to an exon microarray and analyzed by a gene set enrichment analysis. We discovered that long-term exercise training regulated the Reactome gene sets for metabolism (38 gene sets), cell cycle (36 gene sets), disease (27 gene sets), gene expression and transcription (22 gene sets), organelle biogenesis (4 gene sets), cellular response to stimuli (8 gene sets), immune system (8 gene sets), vesicle-mediated transport (4 gene sets), and transport of small molecules (3 gene sets). Specific gene expression included: oxidative catabolism of glucose including PDHB (P < 0.001), PDHX (P < 0.001), MPC1 (P < 0.009), and MPC2 (P < 0.007); Oxidative phosphorylation genes including SDHA (P < 0.006), SDHB (P < 0.001), NDUFB1 (P < 0.002), NDUFA2 (P < 0.001); transcription genes including PGC1α (P < 0.030) and PRKAB2 (P < 0.011); hypertrophy gene MSTN (P < 0.001); and the myokine generating FNDC5 gene (P < 0.008). Long-term electrically induced exercise demethylated the major transcription factor PGC1a. Taken together, these findings support that long-term electrically induced muscle activity regulates key pathways associated with muscle health and systemic metabolism.

Functional electrical stimulation-assisted cycle ergometry in the critically ill: protocol for a randomized controlled trial

BACKGROUND

Intensive care unit (ICU)-acquired weakness is the most important cause of failed functional outcome in survivors of critical care. Most damage occurs during the first week when patients are not cooperative enough with conventional rehabilitation. Functional electrical stimulation-assisted cycle ergometry (FES-CE) applied within 48 h of ICU admission may improve muscle function and long-term outcome.

METHODS

An assessor-blinded, pragmatic, single-centre randomized controlled trial will be performed. Adults (n = 150) mechanically ventilated for < 48 h from four ICUs who are estimated to need > 7 days of critical care will be randomized (1:1) to receive either standard of care or FES-CE-based intensified rehabilitation, which will continue until ICU discharge.

PRIMARY OUTCOME

quality of life measured by 36-Item Short Form Health Survey score at 6 months.

SECONDARY OUTCOMES

functional performance at ICU discharge, muscle mass (vastus ultrasound, N-balance) and function (Medical Research Council score, insulin sensitivity). In a subgroup (n = 30) we will assess insulin sensitivity and perform skeletal muscle biopsies to look at mitochondrial function, fibre typing and regulatory protein expression.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02864745. Registered on 12 August 2016.

Prevention and management of osteoporosis and osteoporotic fractures in persons with a spinal cord injury or disorder: A systematic scoping review

Objectives: The primary objective was to review the literature regarding methodologies to assess fracture risk, to prevent and treat osteoporosis and to manage osteoporotic fractures in SCI/D.Study Design: Scoping review.Settings/Participants: Human adult subjects with a SCI/D.Outcome measures: Strategies to identify persons with SCI/D at risk for osteoporotic fractures, nonpharmacological and pharmacological therapies for osteoporosis and management of appendicular fractures.Results: 226 articles were included in the scoping review. Risk of osteoporotic fractures in SCI is predicted by a combination of DXA-defined low BMD plus clinical and demographic characteristics. Screening for secondary causes of osteoporosis, in particular hyperparathyroidism, hyperthyroidism, vitamin D insufficiency and hypogonadism, should be considered. Current antiresorptive therapies for treatment of osteoporosis have limited efficacy. Use of surgery to treat fractures has increased and outcomes are good and comparable to conservative treatment in most cases. A common adverse event following fracture was delayed healing.Conclusions: Most of the research in this area is limited by small sample sizes, weak study designs, and significant variation in populations studied. Future research needs to address cohort definition and study design issues.

Congenital exercise ability ameliorates muscle atrophy but not spinal cord recovery in spinal cord injury mouse model

Spinal cord injury (SCI) can cause loss of mobility in the limbs, and no drugs, surgical procedures, or rehabilitation strategies provide a complete cure. Exercise capacity is thought to be associated with the causes of many diseases. However, no studies to date have assessed whether congenital exercise ability is related to the recovery of spinal cord injury. High congenital exercise ability (HE) and low congenital exercise ability (LE) mice were artificially bred from the same founder ICR mice. The HE and LE groups still exhibited differences in exercise ability after 13 generations of breeding. Histological staining and immunohistochemistry staining indicated no significant differences between the HE and LE groups on recovery of the spinal cord. In contrast, after SCI, the HE group exhibited better mobility in gait analysis and longer endurance times in the exhaustive swimming test than the LE group. In addition, after SCI, the HE group also exhibited less atrophy than the LE group, and no inflammatory cells appeared. In conclusion, we found that high congenital exercise ability may reduce the rate of muscle atrophy. This result can be applied to sports science and rehabilitation science as a reference for preventive medicine research.

Nutritional status in chronic spinal cord injury: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

The objective was to investigate nutritional status in chronic spinal cord injury (SCI), and compare macronutrient and micronutrient intake to the recommended values by the United States Department of Agriculture (USDA) 2015-2020 Dietary Guidelines for Americans.

SETTING

United States of America.

METHODS

A MEDLINE/PubMed, Google Scholar, Scopus, and Web of Science search was performed, identifying 268 papers. All papers included were English-language papers examining adults with chronic SCI. A meta-analysis was performed to produce weighted averages and 95% confidence intervals (CI) when summary statistics were provided.

RESULTS

The systematic review included 15 articles, while the meta-analysis included 12. Resting metabolic rate (1492 kcal/day; CI: 1414-1569) fell below the able-bodied average, and total energy (1876 kcal/day; CI: 1694-2059) and fiber (17 g/day; CI: 14-20) intake were below USDA guidelines. Protein (319 kcal/day; CI: 294-345) and carbohydrate (969 kcal/day; CI: 851-1087) intake were above guidelines. Fat intake (663 kcal/day; CI: 590-736) was within USDA guidelines. Vitamins A, B5, B7, B9, D, E, potassium, and calcium were deficient, while vitamins B1, B2, B3, B12, C, K, sodium, phosphorus, copper, and zinc were in excess according to USDA guidelines. Vitamin B6, iron, and magnesium were within USDA guidelines.

CONCLUSION

Findings indicate greater energy intake relative to energy needs in those with chronic SCI, and an imbalance in fiber intake and micronutrients compared to the USDA guidelines. Future research examining nutritional health status is needed in order to establish evidence-based, SCI-specific dietary guidelines.

Effects of ursolic acid on sub-lesional muscle pathology in a contusion model of spinal cord injury

Spinal Cord Injury (SCI) results in severe sub-lesional muscle atrophy and fiber type transformation from slow oxidative to fast glycolytic, both contributing to functional deficits and maladaptive metabolic profiles. Therapeutic countermeasures have had limited success and muscle-related pathology remains a clinical priority. mTOR signaling is known to play a critical role in skeletal muscle growth and metabolism, and signal integration of anabolic and catabolic pathways. Recent studies show that the natural compound ursolic acid (UA) enhances mTOR signaling intermediates, independently inhibiting atrophy and inducing hypertrophy. Here, we examine the effects of UA treatment on sub-lesional muscle mTOR signaling, catabolic genes, and functional deficits following severe SCI in mice. We observe that UA treatment significantly attenuates SCI induced decreases in activated forms of mTOR, and signaling intermediates PI3K, AKT, and S6K, and the upregulation of catabolic genes including FOXO1, MAFbx, MURF-1, and PSMD11. In addition, UA treatment improves SCI induced deficits in body and sub-lesional muscle mass, as well as functional outcomes related to muscle function, motor coordination, and strength. These findings provide evidence that UA treatment may be a potential therapeutic strategy to improve muscle-specific pathological consequences of SCI.

Nutritional Health Considerations for Persons with Spinal Cord Injury

Chronic spinal cord injury (SCI) often results in morbidity and mortality due to all-cause cardiovascular disease (CVD) and comorbid endocrine disorders. Several component risk factors for CVD, described as the cardiometabolic syndrome (CMS), are prevalent in SCI, with the individual risks of obesity and insulin resistance known to advance the disease prognosis to a greater extent than other established risks. Notably, adiposity and insulin resistance are attributed in large part to a commonly observed maladaptive dietary/nutritional profile. Although there are no evidence-based nutritional guidelines to address the CMS risk in SCI, contemporary treatment strategies advocate more comprehensive lifestyle management that includes sustained nutritional guidance as a necessary component for overall health management. This monograph describes factors in SCI that contribute to CMS risks, the current nutritional profile and its contribution to CMS risks, and effective treatment strategies including the adaptability of the Diabetes Prevention Program (DPP) to SCI. Establishing appropriate nutritional guidelines and recommendations will play an important role in addressing the CMS risks in SCI and preserving optimal long-term health.

Cutaneous microvascular perfusion responses to insulin iontophoresis are differentially affected by insulin resistance after spinal cord injury

NEW FINDINGS

What is the central question of this study? What impact does insulin resistance have on cutaneous perfusion responses to insulin iontophoresis in vascular beds with markedly reduced or functionally ablated sympathetic nervous system vasomotor function resulting from spinal cord injury? What is the main finding and its importance? Persons with spinal cord injury have sublesional microvascular endothelial dysfunction, as indicated by a blunted cutaneous perfusion response to acetylcholine iontophoresis, and the presence of insulin resistance has a further confounding effect on endothelium-mediated changes to cutaneous perfusion in the lower extremities. Endothelium-mediated mechanisms that regulate skin blood flow might play an integral role in optimizing skin perfusion in vascular beds with sympathetic nervous system vasomotor impairment, such as in spinal cord injury (SCI). Insulin is a vasoactive hormone and second messenger of nitric oxide that facilitates endothelium-mediated dilatation. The effects of insulin resistance (IR) on sublesional cutaneous perfusion responses to insulin provocation have yet to be described in persons with SCI. Persons with SCI and an able-bodied (AB) cohort were divided into subgroups based upon fasting plasma insulin concentration cut-offs for IR (≥13.13 mIU ml^-1 ) or insulin sensitivity (IS; <13.13 mIU ml^-1 ), as follows: AB, IS (ABIS, n = 21); SCI, IS (SCIS, n = 21); AB, IR (ABIR, n = 9); and SCI, IR (SCIR, n = 11). Laser Doppler flowmetry characterized peak blood perfusion unit (BPU) responses (percentage change from baseline) to insulin, acetylcholine or placebo iontophoresis in the lower extremities; BPU responses were log₁₀ transformed to facilitate comparisons, and the net insulin response (NetIns) BPU response was calculated (insulin minus placebo BPU response). The NetIns was significantly greater in both IS groups compared with their corresponding IR group. The acetylcholine-mediated BPU responses in the SCI subgroups were significantly lower than those in the ABIS group. The proportional BPU responses of NetIns to acetylcholine in the IS cohorts (i.e. ABIS and SCIS) were significantly greater (P < 0.05) than that of each IR subgroup. The presence of IR has a confounding effect on sublesional microvascular endothelium-mediated cutaneous perfusion responses to provocation. Preservation of endothelial sensitivity to its agonists appears to be an important modifiable risk factor to optimize cutaneous perfusion in the lower extremities of persons with SCI.

Prevalence and Etiology of Hypogonadism in Young Men With Chronic Spinal Cord Injury: A Cross-Sectional Analysis From Two University-Based Rehabilitation Centers

BACKGROUND

Spinal cord injury (SCI) triggers an "accelerated aging" process that may include development of hypogonadism, even among younger men with SCI; however, few studies have investigated the prevalence or etiology of hypogonadism in men with SCI. Young men with SCI also are at increased risk for developing metabolic dysfunction after injury, which may be exacerbated by concomitant testosterone (T) deficiency, thus identifying the prevalence and risk factors for T deficiency in men with SCI is important for their long-term health.

OBJECTIVE

To investigate the prevalence, risk factors, and etiology of T deficiency (hypogonadism) in otherwise-healthy men with chronic, motor complete SCI.

DESIGN

Secondary cross-sectional analysis.

SETTING

Rehabilitation research centers in Washington, DC, and Miami, Florida.

PARTICIPANTS

Men (n = 58) aged 18-45 years with chronic (≥1 year), motor complete SCI without comorbidities or use of testosterone therapy.

METHODS

Plasma concentrations of hormones were measured with standardized assays. Body composition was assessed with dual-energy x-ray absorptiometry scan.

MAIN OUTCOME MEASUREMENTS

Serum total T and calculated free T.

RESULTS

T deficiency was more common in men after SCI than in a matched cohort of similarly-aged men without SCI (25%, SCI versus 6.7%, non-SCI, P < .001). The risk of hypogonadism appeared to be increased in men with more extensive injury and with higher percent body fat. The majority of men with SCI with low T had low serum LH levels, suggesting that central suppression of the hypothalamic-pituitary-gonadal axis may be the most common etiology of hypogonadism after SCI.

CONCLUSIONS

Hypogonadism is more common in young men with SCI than in similarly aged men without SCI, suggesting that SCI should be identified as a risk factor for T deficiency and that routine screening for hypogonadism should be performed in the SCI population.

LEVEL OF EVIDENCE

II.

Distinct Skeletal Muscle Gene Regulation from Active Contraction, Passive Vibration, and Whole Body Heat Stress in Humans

Skeletal muscle exercise regulates several important metabolic genes in humans. We know little about the effects of environmental stress (heat) and mechanical stress (vibration) on skeletal muscle. Passive mechanical stress or systemic heat stress are often used in combination with many active exercise programs. We designed a method to deliver a vibration stress and systemic heat stress to compare the effects with active skeletal muscle contraction. Purpose: The purpose of this study is to examine whether active mechanical stress (muscle contraction), passive mechanical stress (vibration), or systemic whole body heat stress regulates key gene signatures associated with muscle metabolism, hypertrophy/atrophy, and inflammation/repair. Methods: Eleven subjects, six able-bodied and five with chronic spinal cord injury (SCI) participated in the study. The six able-bodied subjects sat in a heat stress chamber for 30 minutes. Five subjects with SCI received a single dose of limb-segment vibration or a dose of repetitive electrically induced muscle contractions. Three hours after the completion of each stress, we performed a muscle biopsy (vastus lateralis or soleus) to analyze mRNA gene expression. Results: We discovered repetitive active muscle contractions up regulated metabolic transcription factors NR4A3 (12.45 fold), PGC-1α (5.46 fold), and ABRA (5.98 fold); and repressed MSTN (0.56 fold). Heat stress repressed PGC-1α (0.74 fold change; p < 0.05); while vibration induced FOXK2 (2.36 fold change; p < 0.05). Vibration similarly caused a down regulation of MSTN (0.74 fold change; p < 0.05), but to a lesser extent than active muscle contraction. Vibration induced FOXK2 (p < 0.05) while heat stress repressed PGC-1α (0.74 fold) and ANKRD1 genes (0.51 fold; p < 0.05). Conclusion: These findings support a distinct gene regulation in response to heat stress, vibration, and muscle contractions. Understanding these responses may assist in developing regenerative rehabilitation interventions to improve muscle cell development, growth, and repair.

Early exercise after spinal cord injury ('Switch-On'): study protocol for a randomised controlled trial

Background

Spinal cord injury (SCI) leads to a profound muscular atrophy, bone loss and bone fragility. While there is evidence that exercising paralysed muscles may lead to reversal of muscle atrophy in the chronic period after SCI, there is little evidence that exercise can prevent muscle changes early after injury. Moreover, whether exercise can prevent bone loss and microarchitectural decay is not clear.

Methods/Design

A multi-centre, parallel group, assessor-blinded randomised controlled trial will be conducted. Fifty participants with acute spinal cord injury will be recruited from four SCI units in Australia and New Zealand. Participants will be stratified by site and AIS status and randomised to an experimental or control group. Experimental participants will receive a 12-week programme of functional electrical stimulation (FES)-assisted cycling. Control participants will receive a 12-week programme of passive cycling. The primary outcome is muscle cross-sectional area of the thigh and calf measured using magnetic resonance images (MRI) of the leg. Secondary outcomes include serum biomarkers of SCI osteoporosis (sclerostin, P1NP and β-CTX), markers of immune function (IL-6, IL-10, FGF2, INF-γ, TNF-α), neurological function, body composition, depression and quality of life. Leg MRIs will be measured by a single blinded assessor based in Melbourne. Serum samples will be analysed in a central laboratory. All other characteristics will be measured at baseline and 12 weeks by blinded and trained assessors at each site. The first participant was randomised on 27 November 2012.

Discussion

The results of this trial will determine the relative effectiveness of a 12-week programme of FES-assisted cycling versus passive cycling in preventing muscle atrophy and maintaining skeletal integrity after spinal cord injury.

Trial registration

ACTRN12611001079932 (18 October 2011)

Effects of circuit resistance training and timely protein supplementation on exercise-induced fat oxidation in tetraplegic adults

BACKGROUND

Substrate utilization during exercise in persons with spinal cord injury (SCI) remains poorly defined.

PURPOSE

To investigate effects of circuit resistance training (CRT) and timing of protein supplementation (PS) on fuel utilization in persons with tetraplegia.

METHODS

Eleven individuals with chronic tetraplegia underwent 6 months of CRT 3 times weekly. Five randomly assigned participants received immediate PS (iPS) administered in split doses prior to and following all exercise sessions. Other participants consumed a matched dose of PS that was delayed until 24 hours post-exercise (dPS). Participants underwent a maximal graded exercise test (GXT) to volitional exhaustion at 4 conditioning time points: 3 months before (-3mo), at the beginning of (0mo), 3 months into (3mo), and 6 months following (6mo) the CRT conditioning program. Respiratory measures were continuously obtained throughout the GXT via open-circuit spirometry. Fuel utilization and energy expenditure were computed from the respiratory data.

RESULTS

The differences in changes in substrate utilization between the PS groups were not significant as determined by the interaction of PS group and conditioning time point, F (3, 27) = 2.32, P = .098, η(2) P = .205. Maximal absolute fat oxidation did not change significantly from 0 to 6mo (mean difference, 0.014 ± 0.031 g/min; P = .170), and fat oxidation remained low never exceeding an average of 0.10 ± 0.09 g/min for any given exercise intensity.

CONCLUSION

Maximum fat utilization during exercise and fat utilization at matched exercise intensities were not increased in persons with tetraplegia, independent of PS, and levels of fat oxidation remained low after training.

Longitudinal changes in medical complications in adults with pediatric-onset spinal cord injury

OBJECTIVES

To determine longitudinal changes in the occurrence of medical complications in adults with pediatric-onset spinal cord injury (SCI).

DESIGN

Longitudinal study of long-term outcomes.

SETTING

Community.

PARTICIPANTS

Individuals who had sustained an SCI before age 19, were 23 years of age or older at initial interview, and followed annually between 1996 and 2011. They were classified into four American Spinal Injury Association (ASIA) Impairment Scale (AIS) severity groups: C1-4 AIS ABC, C5-8 AIS ABC, T1-S5 AIS ABC, AIS D.

OUTCOME MEASURES

Generalized estimating equation (GEE) models were formulated to obtain the odds ratio (OR) of having a medical complication over time.

RESULTS

A total of 1793 interviews were conducted among 226 men and 125 women (86% Caucasian; age at baseline, 26.7 ± 3.6 years; time since injury at baseline, 12.9 ± 5.2 years). Odds of complication occurrence over time varied among severity groups, with increased ORs of severe urinary tract infection (1.05, confidence interval (CI) 1.02-1.09), autonomic dysreflexia (AD) (1.09, CI 1.05-1.14), spasticity (1.06, CI 1.01-1.11), pneumonia/respiratory failure (1.09, CI 1.03-1.16), and hypertension/cardiac disease (1.07, CI 1.01-1.15) in the C1-4 ABC group; AD (1.08, CI 1.04-1.13) and pneumonia/respiratory failure (1.09, CI 1.02-1.16) in the C5-8 ABC group; and hypertension/cardiac disease (1.08, CI 1.02-1.14) in the T1-S5 ABC group. Upper extremity joint pain had increased odds of occurrence in all injury severity groups.

CONCLUSION

The significantly increased odds of having medical complications over time warrants awareness of risk factors and implementation of preventive measures to avoid adverse consequences of complications and to maintain independence in individuals with pediatric-onset SCI.

Spinal cord injury and type 2 diabetes: results from a population health survey

OBJECTIVE

The objective of this study was to evaluate the association between spinal cord injury (SCI) and type 2 diabetes in a large representative sample and to determine whether an association exists irrespective of known risk factors for type 2 diabetes.

METHODS

Data were obtained on 60,678 respondents to the Statistics Canada 2010 Cycle of the cross-sectional Canadian Community Health Survey. Multivariable logistic regression, incorporating adjustment for confounders and probability weights to account for the Canadian Community Health Survey sampling method, was conducted to quantify this association.

RESULTS

After adjustment for both sex and age, SCI was associated with a significant increased odds of type 2 diabetes (adjusted odds ratio = 1.66, 95% confidence interval 1.16-2.36). These heightened odds persisted after additional adjustment for smoking status, hypertension status, body mass index, daily physical activity, alcohol intake, and daily consumption of fruits and vegetables (fully adjusted odds ratio = 2.45, 95% confidence interval 1.34-4.47).

CONCLUSIONS

There is a strong association between SCI and type 2 diabetes, which is not explained by known risk factors for type 2 diabetes.

Physiological responses to exergaming after spinal cord injury

PURPOSE

To investigate whether exergaming satisfies guideline-based intensity standards for exercise conditioning (40%/50% oxygen uptake reserve [VO2R] or heart rate reserve (HRR), or 64%/70% of peak heart rate [HRpeak]) in persons with paraplegia.

METHODS

Nine men and women (18-65 years old) with chronic paraplegia (T1-L1, AIS A-C) underwent intensity-graded arm cycle exercise (AE) to evaluate VO2peak and HRpeak. On 2 randomized nonconsecutive days, participants underwent graded exercise using a custom arm cycle ergometer that controls the video display of a Nintendo Gamecube (GameCycle; Three Rivers Holdings LLC, Mesa, AZ) or 15 minutes of incrementally wrist-weighted tennis gameplay against a televised opponent (XaviX Tennis System; SSD Co Ltd, Kusatsu, Japan).

RESULTS

GameCycle exergaming (GCE) resistance settings ≥0.88 Nm evoked on average ≥50% VO2R. During XaviX Tennis System exergaming (XTSE) with wrist weights ≥2 lbs, average VO2 reached a plateau of ~40% VO2R. Measurements of HR were highly variable and reached average values ≥50% HRR during GCE at resistance settings ≥0.88 Nm. During XTSE, average HR did not reach threshold levels based on HRR for any wrist weight (20%-35% HRR).

CONCLUSIONS

On average, intensity responses to GCE at resistance setting ≥0.88 Nm were sufficient to elicit exercise intensities needed to promote cardiorespiratory fitness in individuals with SCI. The ability of XTSE to elicit cardiorespiratory fitness benefits is most likely limited to individuals with very low fitness levels and may become subminimal with time if used as a conditioning stimulus.

Normative blood pressure and heart rate in pediatric spinal cord injury

BACKGROUND

Cardiovascular measures in children with spinal cord injury (SCI) may vary depending on the child's age and physical development in addition to injury-related factors. Developmental changes should be considered when addressing cardiovascular complications in this population.

OBJECTIVES

To determine baseline blood pressure (BP) and heart rate (HR) measurements in youth with SCI, and to investigate differences in BP and HR in relation to age, gender, body mass index (BMI), and injury-related factors.

METHODS

Retrospective chart review was conducted for youth under 19 years who had been admitted for rehabilitation at 1 of 2 pediatric SCI programs. Systolic (SBP) and diastolic (DBP) blood pressures and HR were collected in the morning and afternoon on 3 consecutive days. Mean SBP, DBP, and HR were compared among 4 age groups (0-5 years, 6-12 years, 13-15 years, and 16-18 years) and by gender. Diurnal variations were determined according to level and severity of injury. Associations with BMI and injury-related factors were examined. Charts of 315 youths were reviewed: mean age was 12.3 years, 59% were male, 75% were Caucasian, 62% had complete injury, and 66% had paraplegia.

RESULTS

With increasing age, SBP and DBP increased and HR decreased. SBP and DBP were positively correlated with BMI. SBP was higher in males, those with incomplete injury, and those with paraplegia. HR was higher in females. There was no association between cardiovascular measures and injury duration.

CONCLUSION

BP and HR are a function of age, BMI, and completeness and level of injury in youth with SCI. Awareness of baseline measures will allow for more effective management of cardiovascular complications, especially in youth presenting with atypical symptoms.

Alterations in mouse hypothalamic adipokine gene expression and leptin signaling following chronic spinal cord injury and with advanced age

Chronic spinal cord injury (SCI) results in an accelerated trajectory of several cardiovascular disease (CVD) risk factors and related aging characteristics, however the molecular mechanisms that are activated have not been explored. Adipokines and leptin signaling are known to play a critical role in neuro-endocrine regulation of energy metabolism, and are now implicated in central inflammatory processes associated with CVD. Here, we examine hypothalamic adipokine gene expression and leptin signaling in response to chronic spinal cord injury and with advanced age. We demonstrate significant changes in fasting-induced adipose factor (FIAF), resistin (Rstn), long-form leptin receptor (LepRb) and suppressor of cytokine-3 (SOCS3) gene expression following chronic SCI and with advanced age. LepRb and Jak2/stat3 signaling is significantly decreased and the leptin signaling inhibitor SOCS3 is significantly elevated with chronic SCI and advanced age. In addition, we investigate endoplasmic reticulum (ER) stress and activation of the uncoupled protein response (UPR) as a biological hallmark of leptin resistance. We observe the activation of the ER stress/UPR proteins IRE1, PERK, and eIF2alpha, demonstrating leptin resistance in chronic SCI and with advanced age. These findings provide evidence for adipokine-mediated inflammatory responses and leptin resistance as contributing to neuro-endocrine dysfunction and CVD risk following SCI and with advanced age. Understanding the underlying mechanisms contributing to SCI and age related CVD may provide insight that will help direct specific therapeutic interventions.

Assessing stress in disability: developing and piloting the Disability Related Stress Scale

BACKGROUND

Stress negatively influences health, but few scales capture unique stressors encountered by people with physical disability.

OBJECTIVE/HYPOTHESIS

Conduct a pilot study to develop and evaluate the factor structure of a stress measure targeting unique stressors facing people with physical limitations due to impaired movement of the upper and lower extremities.

METHODS

Development of the Disability Related Stress Scale (DRSS) included: (1) obtaining input regarding content and items from focus groups and outside experts and (2) piloting the instrument. Participants recruited from an independent living center attended a focus group or completed the pilot survey. The piloted measure was a 107 item two-part survey. Part 1 assessed stressors encountered over the past week and Part 2 assessed stressors encountered over the past six months. Participants included a convenience sample of 143 adults who experienced a physical limitation; 26 attended focus groups and 117 completed the instrument. Respondents were predominantly women (60%), Caucasian (58%), and unemployed (92%). Respondents were 50.51 ± 14.46 years old and had lived with their disability for 15.64 ± 13.04 years.

RESULTS

Exploratory factor analyses revealed a 4-factor solution for Part 1 and a 2-factor solution for Part 2 of the DRSS. Estimates of internal consistency (Part 1 Cronbach's α = .78-84; Part 2 Cronbach's α = .72) and factor loadings (.40-1.00 for Part 1; .43-.87 for Part 2) indicate adequate reliability for all subscales.

CONCLUSIONS

Preliminary results provide initial support for the instrument's reliability and factor structure although further validation studies are warranted.

Systemic and cerebral hemodynamics during cognitive testing

OBJECTIVE

Cognitive deficits are reported in 10-60% of individuals with SCI, the primary etiology of these deficits is believed to be concomitant traumatic brain injury (TBI). We recently documented diminished memory and marginally deficient attention and processing speed in individuals with SCI discordant for hypotension but matched for TBI.

METHODS

Twenty-nine individuals participated: 16 non-SCI controls, 6 paraplegic (T2-T10) and 7 tetraplegic (C4-C8). The Stroop test was used to measure cognitive function and transcranial Doppler ultrasound was used to measure cerebral blood flow (CBF) while resting (5 min) and continuously during cognitive testing. Mean arterial pressure (MAP) was calculated from three brachial blood pressures and cerebral vascular resistance index was calculated as: CVRi = MAP/CBF.

RESULTS

The paraplegia group (54 ± 6) was marginally older than the non-SCI (42 ± 15; p = 0.06) and tetraplegic (42 ± 11; p = 0.09) groups. Compared to non-SCI group, normalized t-score on the Stroop Color (SC) task was significantly lower in the paraplegic group (p < 0.05). In the tetraplegic group, MAP was significantly lower (p < 0.05) than the non-SCI and paraplegic groups, and related to SC t-score (r (2) = 0.873; p < 0.01). In the paraplegic group, CBF was reduced (p < 0.05) and CVRi increased (p < 0.05) compared to the non-SCI group, and CVRi was increased compared to the tetraplegic group (p < 0.05). A significant inverse relationship was noted between change in CVRi and SC t-score in the non-SCI group.

CONCLUSION

Asymptomatic hypotension relates to cognitive performance in persons with tetraplegia; therefore, BP normalization should be considered. The inappropriate cerebral vascular response to cognitive testing and poor test performance should be investigated in persons with paraplegia.

Effects on Locomotion, Muscle, Bone, and Blood Induced by a Combination Therapy Eliciting Weight-Bearing Stepping in Nonassisted Spinal Cord–Transected Mice

Background. The health benefits associated with physical activity–based rehabilitation in patients with no lower-extremity motor function after a spinal cord injury (SCI) is uncertain. Methods. The authors assessed signs of efficacy, safety, and utility associated with a novel pharmacological combination therapy to activate central pattern generator (CPG) activity and corresponding locomotor activity in complete thoracic Th9/10-transected mice. Results. Subcutaneous administration 4 times per week for 1 month of 1.5 mg/kg buspirone, 1.5 mg/kg apomorphine, 12.5 mg/kg benserazide, and 50 mg/kg L-DOPA induced episodes of weight-bearing stepping on a treadmill in nonassisted paraplegic mice for 45-minute sessions. Hindlimb muscle cross-sectional area and fiber area values as well as several blood cell constituent levels assessed at 30 days postinjury were positively affected by the combination therapy, as compared with controls. Episodes of locomotion remained effective on each treatment. Femoral bone mineral density loss was not prevented by triple therapy. Conclusion. Although translation of these findings needs further experimentation, similar pharmacological activation of the CPG offers a novel therapeutic target to provide some health benefits in motor-complete SCI patients.

Oral administration of a tri-therapy for central pattern generator activation in paraplegic mice: proof-of-concept of efficacy

Spinal cord injury (SCI) is a neurological condition, for which no cure exists, typically leading to an immediate and irreversible loss of sensory and voluntary motor functions accompanied by significant health problems. We conducted proof-of-concept experiments aimed at assessing efficacy upon oral administration of a novel combination therapy for central pattern generator (CPG) activation and corresponding locomotor movement generation in completely paraplegic animals. Co-administration orally (by gavage) of buspirone, levodopa and carbidopa was found to dose-dependently induce episodes of steady weight-bearing stepping in low-thoracic (Th9/10) spinal cord-transected (Tx) mice (with no other form of assistance or training). Robust hindlimb stepping with weight-bearing capabilities was induced with the tri-therapy but not with clinically relevant doses of these compounds administered separately. These results provide evidence suggesting that this drug combination may be ideally suited to constitute a first-in-class therapy (CPG activator) for locomotor activity induction in chronic SCI individuals, given that efficacy was shown using commercially available brain-permeable small molecules, already known as safe for the treatment of various neurological indications.