Locomotor Exercise Enhances Supraspinal Control of Lower-Urinary-Tract Activity to Improve Micturition Function after Contusive Spinal-Cord Injury

The Perfect Step is the first one: Improving the quality of life for patients with spinal cord injuries through structured exercise

CONTEXT

More than 1 million people live with spinal cord injuries (SCI) in the United States alone. Despite research suggesting improvement in functional activities in patients who participate in regular physical activity, there is limited data on the specific impact of exercise as it pertains to patient-reported quality-of-life (QoL) measures of mood, pain, independence, or medical complications. Patients with SCI participating in a longitudinal exercise program at a community-based fitness facility (The Perfect Step) in Pomona, California were invited to participate in this study. This program consisted of at least two hours a week of exercise-based therapy, loadbearing, and neuroplasticity retraining for two years. Participants were asked to retrospectively rate patient-reported quality-of-life outcomes at the start of participation in the program, and at 6, 12, and 24 months after the program start as measured by an 89-item SCI QoL questionnaire covering domains including mood (39 items), pain (16 items), independence (7 items), bladder function (14 items), and pressure ulcers (13 items). 24 patients with SCI (16 cervical, 4 thoracic, 3 lumbar, 1 unspecified) were included in the final analysis.

FINDINGS

Wilcoxon rank sum tests were used to compare patient-reported outcome measures over time. Patients reported statistically significantly improved outcomes across all domains at all timepoints to varying degrees, with improvement in 73/89 items at 6 months, 57/89 at 12 months, and 65/89 at 24 months after participation start (P < 0.05, all).

CONCLUSION/CLINICAL RELEVANCE

Patients with SCI engaging in a structured exercise program demonstrated sustainable, longitudinal improvements in mood, pain control, independence, and fewer impairments related to bladder function and pressure ulcers. Physicians should consider the integration of structured exercise into the rehabilitation program alongside traditional medical care to optimize the quality of life for those with SCI. Future research should involve a direct comparison of QoL in patients with SCI participating in structured exercise versus those who are not.

Differential effects of exercise and hormone treatment on spinal cord injury-induced changes in micturition and morphology of external urethral sphincter motoneurons

Background

Spinal cord injury (SCI) results in lesions that destroy tissue and spinal tracts, leading to deficits in locomotor and autonomic function. We have previously shown that after SCI, surviving motoneurons innervating hindlimb muscles exhibit extensive dendritic atrophy, which can be attenuated by treadmill training or treatment with gonadal hormones post-injury. We have also shown that following SCI, both exercise and treatment with gonadal hormones improve urinary function. Animals exercised with forced running wheel training show improved urinary function as measured by bladder cystometry and sphincter electromyography, and treatment with gonadal hormones improves voiding patterns as measured by metabolic cage testing.

Objective

The objective of the current study was to examine the potential protective effects of exercise or hormone treatment on the structure and function of motoneurons innervating the external urethral sphincter (EUS) after contusive SCI.

Methods

Gonadally intact young adult male rats received either a sham or a thoracic contusion injury. Immediately after injury, one cohort of animals was implanted with subcutaneous Silastic capsules filled with estradiol (E) and dihydrotestosterone (D) or left blank; continuous hormone treatment occurred for 4 weeks post-injury. A separate cohort of SCI-animals received either 12 weeks of forced wheel running exercise or no exercise treatment starting two weeks after injury. At the end of treatment, urinary void volume was measured using metabolic cages and EUS motoneurons were labeled with cholera toxin-conjugated horseradish peroxidase, allowing for assessment of dendritic morphology in three dimensions.

Results

Locomotor performance was improved in exercised animals after SCI. Void volumes increased after SCI in all animals; void volume was unaffected by treatment with exercise, but was dramatically improved by treatment with E + D. Similar to what we have previously reported for hindlimb motoneurons after SCI, dendritic length of EUS motoneurons was significantly decreased after SCI compared to sham animals. Exercise did not reverse injury-induced atrophy, however E + D treatment significantly protected dendritic length.

Conclusions

These results suggest that some aspects of urinary dysfunction after SCI can be improved through treatment with gonadal hormones, potentially through their effects on EUS motoneurons. Moreover, a more comprehensive treatment regime that addresses multiple SCI-induced sequelae, i.e., locomotor and voiding deficits, would include both hormones and exercise.