Effectiveness of intense, activity-based physical therapy for individuals with spinal cord injury in promoting motor and sensory recovery: is olfactory mucosa autograft a factor?

Challenges in Translating Regenerative Therapies for Spinal Cord Injury

Regenerating the injured spinal cord is a substantial challenge with many obstacles that need to be overcome to achieve robust functional benefits. This abundance of hurdles can partly explain the limited success when applying regenerative intervention treatments in animal models and/or people. In this article, we elaborate on a few of these obstacles, starting with the applicability of animal models and how they compare to the clinical setting. We then discuss the requirement for combinatorial interventions and the associated problems in experimental design, including the addition of rehabilitative training. The article expands on differences in lesion sizes and locations between humans and common animal models, and how this difference can determine the success or failure of an intervention. An additional and frequently overlooked problem in the translation of interventions that applies beyond the field of neuroregeneration is the reporting bias and the lack of transparency in reporting findings. New data mandates are tackling this problem and will eventually result in a more balanced view of the field. Finally, we will discuss strategies to negotiate the challenging course of successful translation to facilitate successful translation of regeneration promoting interventions.

Early and intensive motor training to enhance neurological recovery in people with spinal cord injury: trial protocol

STUDY DESIGN

Protocol for a multi-centre randomised controlled trial (the SCI-MT trial).

OBJECTIVES

To determine whether 10 weeks of intensive motor training enhances neurological recovery in people with recent spinal cord injury (SCI).

SETTING

Fifteen spinal injury units in Australia, Scotland, England, Italy, Netherlands, Norway, and Belgium.

METHODS

A pragmatic randomised controlled trial will be undertaken. Two hundred and twenty people with recent SCI (onset in the preceding 10 weeks, American Spinal Injuries Association Impairment Scale (AIS) A lesion with motor function more than three levels below the motor level on one or both sides, or an AIS C or D lesion) will be randomised to receive either usual care plus intensive motor training (12 h of motor training per week for 10 weeks) or usual care alone. The primary outcome is neurological recovery at 10 weeks, measured with the Total Motor Score from the International Standards for Neurological Classification of SCI. Secondary outcomes include global measures of motor function, ability to walk, quality of life, participants' perceptions about ability to perform self-selected goals, length of hospital stay and participants' impressions of therapeutic benefit at 10 weeks and 6 months. A cost-effectiveness study and process evaluation will be run alongside the trial. The first participant was randomised in June 2021 and the trial is due for completion in 2025.

CONCLUSIONS

The findings of the SCI-MT Trial will guide recommendations about the type and dose of inpatient therapy that optimises neurological recovery in people with SCI.

TRIAL REGISTRATION

ACTRN12621000091808 (1.2.2021).

Cell therapies for spinal cord injury: a review of the clinical trials and cell-type therapeutic potential

Spinal cord injury (SCI) is an as yet untreatable neuropathology that causes severe dysfunction and disability. Cell-based therapies hold neuroregenerative and neuroprotective potential, but, although being studied in SCI patients for more than two decades, long-term efficacy and safety remain unproven, and which cell types result in higher neurological and functional recovery remains under debate. In a comprehensive scoping review of 142 reports and registries of SCI cell-based clinical trials, we addressed the current therapeutical trends and critically analysed the strengths and limitations of the studies. Schwann cells, olfactory ensheathing cells (OECs), macrophages and various types of stem cells have been tested, as well as combinations of these and other cells. A comparative analysis between the reported outcomes of each cell type was performed, according to gold-standard efficacy outcome measures like the ASIA impairment scale, motor and sensory scores. Most of the trials were in the early phases of clinical development (phase I/II), involved patients with complete chronic injuries of traumatic aetiology and did not display a randomized comparative control arm. Bone marrow stem cells and OECs were the most commonly tested cells, while open surgery and injection were the main methods of delivering cells into the spinal cord or submeningeal spaces. Transplantation of support cells, such as OECs and Schwann cells, resulted in the highest ASIA Impairment Scale (AIS) grade conversion rates (improvements in ∼40% of transplanted patients), which surpassed the spontaneous improvement rate expected for complete chronic SCI patients within 1 year post-injury (5-20%). Some stem cells, such as peripheral blood-isolated and neural stem cells, offer potential for improving patient recovery. Complementary treatments, particularly post-transplantation rehabilitation regimes, may contribute highly to neurological and functional recovery. However, unbiased comparisons between the tested therapies are difficult to draw, given the great heterogeneity of the design and outcome measures used in the SCI cell-based clinical trials and how these are reported. It is therefore crucial to standardize these trials when aiming for higher value clinical evidence-based conclusions.

Designing a Clinical Trial with Olfactory Ensheathing Cell Transplantation-Based Therapy for Spinal Cord Injury: A Position Paper

Spinal cord injury (SCI) represents an urgent unmet need for clinical reparative therapy due to its largely irreversible and devastating effects on patients, and the tremendous socioeconomic burden to the community. While different approaches are being explored, therapy to restore the lost function remains unavailable. Olfactory ensheathing cell (OEC) transplantation is a promising approach in terms of feasibility, safety, and limited efficacy; however, high variability in reported clinical outcomes prevent its translation despite several clinical trials. The aims of this position paper are to present an in-depth analysis of previous OEC transplantation-based clinical trials, identify existing challenges and gaps, and finally propose strategies to improve standardization of OEC therapies. We have reviewed the study design and protocols of clinical trials using OEC transplantation for SCI repair to investigate how and why the outcomes show variability. With this knowledge and our experience as a team of biologists and clinicians with active experience in the field of OEC research, we provide recommendations regarding cell source, cell purity and characterisation, transplantation dosage and format, and rehabilitation. Ultimately, this position paper is intended to serve as a roadmap to design an effective clinical trial with OEC transplantation-based therapy for SCI repair.

Current progress of rehabilitative strategies in stem cell therapy for spinal cord injury: a review

Stem cell-based regenerative therapy has opened an avenue for functional recovery of patients with spinal cord injury (SCI). Regenerative rehabilitation is attracting wide attention owing to its synergistic effects, feasibility, non-invasiveness, and diverse and systemic properties. In this review article, we summarize the features of rehabilitation, describe the mechanism of combinatorial treatment, and discuss regenerative rehabilitation in the context of SCI. Although conventional rehabilitative methods have commonly been implemented alone, especially in studies of acute-to-subacute SCI, the combinatorial effects of intensive and advanced methods, including various neurorehabilitative approaches, have also been reported. Separating the concept of combined rehabilitation from regenerative rehabilitation, we suggest that the main roles of regenerative rehabilitation can be categorized as conditioning/reconditioning, functional training, and physical exercise, all of which are indispensable for enhancing functional recovery achieved using stem cell therapies.

Pathophysiology, Biomarkers, and Therapeutic Modalities Associated with Skeletal Muscle Loss Following Spinal Cord Injury

A spinal cord injury (SCI) may lead to loss of strength, sensation, locomotion and other body functions distal to the lesion site. Individuals with SCI also develop secondary conditions due to the lack of skeletal muscle activity. As SCI case numbers increase, recent studies have attempted to determine the best options to salvage affected musculature before it is lost. These approaches include pharmacotherapeutic options, immunosuppressants, physical activity or a combination thereof. Associated biomarkers are increasingly used to determine if these treatments aid in the protection and reconstruction of affected musculature.

Multi-target approaches to CNS repair: olfactory mucosa-derived cells and heparan sulfates

Spinal cord injury (SCI) remains one of the biggest challenges in the development of neuroregenerative therapeutics. Cell transplantation is one of numerous experimental strategies that have been identified and tested for efficacy at both preclinical and clinical levels in recent years. In this Review, we briefly discuss the state of human olfactory cell transplantation as a therapy, considering both its current clinical status and its limitations. Furthermore, we introduce a mesenchymal stromal cell derived from human olfactory tissue, which has the potential to induce multifaceted reparative effects in the environment within and surrounding the lesion. We argue that no single therapy will be sufficient to treat SCI effectively and that a combination of cell-based, rehabilitation and pharmaceutical interventions is the most promising approach to aid repair. For this reason, we also introduce a novel pharmaceutical strategy based on modifying the activity of heparan sulfate, an important regulator of a wide range of biological cell functions. The multi-target approach that is exemplified by these types of strategies will probably be necessary to optimize SCI treatment.

Transcutaneous Electrical Spinal Stimulation Promotes Long-Term Recovery of Upper Extremity Function in Chronic Tetraplegia

Upper extremity function is the highest priority of tetraplegics for improving quality of life. We aim to determine the therapeutic potential of transcutaneous electrical spinal cord stimulation for restoration of upper extremity function. We tested the hypothesis that cervical stimulation can facilitate neuroplasticity that results in long-lasting improvement in motor control. A 62-year-old male with C3, incomplete, chronic spinal cord injury (SCI) participated in the study. The intervention comprised three alternating periods: 1) transcutaneous spinal stimulation combined with physical therapy (PT); 2) identical PT only; and 3) a brief combination of stimulation and PT once again. Following four weeks of combined stimulation and physical therapy training, all of the following outcome measurements improved: the Graded Redefined Assessment of Strength, Sensation, and Prehension test score increased 52 points and upper extremity motor score improved 10 points. Pinch strength increased 2- to 7-fold in left and right hands, respectively. Sensation recovered on trunk dermatomes, and overall neurologic level of injury improved from C3 to C4. Most notably, functional gains persisted for over 3 month follow-up without further treatment. These data suggest that noninvasive electrical stimulation of spinal networks can promote neuroplasticity and long-term recovery following SCI.

A Systematic Review of Experimental Strategies Aimed at Improving Motor Function after Acute and Chronic Spinal Cord Injury

While various approaches have been proposed in clinical trials aimed at improving motor function after spinal cord injury in humans, there is still limited information regarding the scope, methodological quality, and evidence associated with single-intervention and multi-intervention approaches. A systematic review performed using the PubMed search engine and the key words "spinal cord injury motor recovery" identified 1973 records, of which 39 were selected (18 from the search records and 21 from reference list inspection). Study phase ( clinicaltrials.org criteria) and methodological quality (Cochrane criteria) were assessed. Studies included proposed a broad range of single-intervention (encompassing cell therapies, pharmacology, electrical stimulation, rehabilitation) (encompassing cell therapies, pharmacology, electrical stimulation, rehabilitation) and multi-intervention approaches (that combined more than one strategy). The highest evidence level was for Phase III studies supporting the role of multi-intervention approaches that contained a rehabilitation component. Quality appraisal revealed that the percentage of selected studies classified with high risk of bias by Cochrane criteria was as follows: random sequence generation = 64%; allocation concealment = 77%; blinding of participants and personnel = 69%; blinding of outcome assessment = 64%; attrition = 44%; selective reporting = 44%. The current literature contains a high proportion of studies with a limited ability to measure efficacy in a valid manner because of low methodological strength in all items of the Cochrane risk of bias assessment. Recommendations to decrease bias are discussed and include increased methodological rigor in the study design and recruitment of study participants, and the use of electrophysiological and imaging measures that can assess functional integrity of the spinal cord (and may be sufficiently sensitive to detect changes that occur in response to therapeutic interventions).

Road collisions as a cause of traumatic spinal cord injury in ireland, 2001-2010

BACKGROUND

Road collisions remain the leading cause of traumatic spinal cord injury (TSCI) in the world. Half of all TSCIs in Ireland in 2000 were caused by road collisions. Since then, there has been a downward trend in road fatalities coincident with implemented road safety strategies.

OBJECTIVE

To examine the incidence of TSCI resulting from road collisions from 2001 to 2010.

METHOD

This is a retrospective study using the hospital inpatient enquiry database of the tertiary referral center, which houses the national spinal injuries unit. Information retrieved included total numbers of patients with TSCI and number of TSCIs due to road collisions from 2001 through 2010, age groups affected, and the gender balance.

RESULTS

Over the 10-year period studied, the incidence rate of TSCI due to road collisions declined, although this did not reach statistical significance. The largest numbers of all TSCIs and TSCIs due to road collisions were in the 20- to 29-year age category and the male gender.

CONCLUSIONS

As mortality due to road collisions declined, so did the number of TSCIs from the same etiology. An impactful road safety campaign is likely to have influenced these trends.

Activity-based therapy for recovery of walking in individuals with chronic spinal cord injury: results from a randomized clinical trial

OBJECTIVE

To examine the effects of activity-based therapy (ABT) on neurologic function, walking ability, functional independence, metabolic health, and community participation.

DESIGN

Randomized controlled trial with delayed treatment design.

SETTING

Outpatient program in a private, nonprofit rehabilitation hospital.

PARTICIPANTS

Volunteer sample of adults (N=48; 37 men and 11 women; age, 18-66y) with chronic (≥12mo postinjury), motor-incomplete (ASIA Impairment Scale grade C or D) spinal cord injury (SCI).

INTERVENTIONS

A total of 9h/wk of ABT for 24 weeks including developmental sequencing; resistance training; repetitive, patterned motor activity; and task-specific locomotor training. Algorithms were used to guide group allocation, functional electrical stimulation utilization, and locomotor training progression.

MAIN OUTCOME MEASURES

Neurologic function (International Standards for Neurological Classification of Spinal Cord Injury); walking speed and endurance (10-meter walk test, 6-minute walk test, and Timed Up and Go test); community participation (Spinal Cord Independence Measure, version III, and Reintegration to Normal Living Index); and metabolic function (weight, body mass index, and Quantitative Insulin Sensitivity Check).

RESULTS

Significant improvements in neurologic function were noted for experimental versus control groups (International Standards for Neurological Classification of Spinal Cord Injury total motor score [5.1±6.3 vs 0.9±5.0; P=.024] and lower extremity motor score [4.2±5.2 vs -0.6±4.2; P=.004]). Significant differences between experimental and control groups were observed for 10-meter walk test speed (0.096±0.14m/s vs 0.027±0.10m/s; P=.036) and 6-minute walk test total distance (35.97±48.2m vs 3.0±25.5m; P=.002).

CONCLUSIONS

ABT has the potential to promote neurologic recovery and enhance walking ability in individuals with chronic, motor-incomplete SCI. However, further analysis is needed to determine for whom ABT is going to lead to meaningful clinical benefits.