Remote Ischemic conditioning as an emerging tool to improve corticospinal transmission in individuals with chronic spinal cord injury.

PURPOSE OF REVIEW: Remote ischemic conditioning (RIC) involves transient blood flow restriction to one limb leading to systemic tissue-protective effects. RIC shares some potential underlying mechanisms with intermittent hypoxia (IH), in which brief bouts of systemic hypoxia trigger increases in growth factor expression and neural plasticity. RIC has shown promise in acute myocardial infarction and stroke but may be applicable toward chronic neuropathology as well. Consequently, this review discusses similarities and differences between RIC and IH and presents preliminary and ongoing research findings regarding RIC. RECENT FINDINGS: Several publications demonstrated that combining RIC with motor training may enhance motor learning in adults with intact nervous systems, though the precise mechanisms were unclear. Our own preliminary data has found that RIC, in conjunction with task specific exercise, can increase corticospinal excitability in a subset of people without neurological injury and in those with chronic cervical spinal cord injury or amyotrophic lateral sclerosis. SUMMARY: RIC is a low-cost intervention easy to deliver in a clinical or home setting. Its potential application to facilitate neural plasticity and motor learning during rehabilitation training for individuals with chronic neurological disorders is a novel concept requiring further investigation to characterize mechanisms, safety, and efficacy.

Health impacts reported in the Spinal Cord Injury COVID-19 Pandemic Experience Survey (SCI-CPES).

CONTEXT: In people with spinal cord injury (SCI), infections are a leading cause of death, and there is a high prevalence of diabetes mellitus, obesity, and hypertension, which are all comorbidities associated with worse outcomes after COVID-19 infection. OBJECTIVE: To characterize self-reported health impacts of COVID-19 on people with SCI related to exposure to virus, diagnosis, symptoms, complications of infection, and vaccination. METHODS: The Spinal Cord Injury COVID-19 Pandemic Experience Survey (SCI-CPES) study was administered to ask people with SCI about their health and other experiences during the COVID-19 pandemic. RESULTS: 223 community-living people with SCI (male = 71%; age = 52±15 years [mean±SD]; paraplegia = 55%) completed the SCI-CPES. Comorbidities first identified in the general population as associated with poor outcomes after COVID-19 infection were commonly reported in this SCI sample: hypertension (30%) and diabetes (13%). 23.5% of respondents reported a known infection exposure from someone who visited (13.5%) or lived in their home (10%). During the study, which included a timeframe when testing was either unavailable or scarce, 61% of respondents were tested for COVID-19; 14% tested or were presumed positive. Fever, fatigue, and chills were the most common symptoms reported. Of the 152 respondents surveyed after COVID-19 vaccines became available, 82% reported being vaccinated. Race and age were significantly associated with positive vaccination status: most (78%) individuals who were vaccinated identified as Non-Hispanic White and were older than those who reported being unvaccinated (57±14 vs. 43±13 years, mean±SD). CONCLUSIONS: Self-reported COVID-19 symptoms were relatively uncommon and not severe in this sample of people with SCI. Potential confounders and limitations include responder, recruitment and self-reporting biases and changing pandemic conditions. Future studies on this topic should query social distancing and other behavioral strategies. Large retrospective chart review studies may provide additional data on incidence and prevalence of COVID-19 infections, symptoms, and severities in the SCI population.

Development of the Spinal Cord Injury COVID-19 Pandemic Experience Survey (SCI-CPES).

CONTEXT: Early during the COVID-19 pandemic, rehabilitation providers received reports from people with spinal cord injury (SCI) of considerable disruptions in caregiver services, medical and nursing care, and access to equipment and supplies; concomitantly, the medical community raised concerns related to the elevated risk of acquiring the infection due to SCI-specific medical conditions. Due to the novel nature of the pandemic, few tools existed to systematically investigate the outcomes and needs of people with SCI during this emergency. OBJECTIVE: To develop a multidimensional assessment tool for surveying the experience of the COVID-19 pandemic on physical and psychological health, employment, caregiving services, medical supplies and equipment, and the delivery of medical care for people with SCI. METHODS: The Spinal Cord Injury COVID-19 Pandemic Experience Survey (SCI-CPES) study, conducted between July 2020 through August 2021, surveyed people with SCI about their experiences during the early COVID-19 pandemic. The SCI-CPES was developed by a SCI care and research consortium using an iterative process. RESULTS: Two hundred and twenty-three people completed the survey. Most respondents resided in the consortium catchment area. As the survey progressed, online informed consent became available allowing dissemination of the SCI-CPES nationally. CONCLUSIONS: The consortium rapidly implemented the capture of experiences with COVID-19 pandemic directly from people with SCI, including survey creation, institutional approvals, distribution, online e-consenting, and data collection. In the future, the SCI-CPES is adaptable for use in other types of emergencies and disasters.

Experiences and recommendations from people with spinal cord injury following participation in a disability education session at an allopathic medical school: a qualitative study.

BACKGROUND: Students in half of US medical schools do not receive formal instruction in providing medical care for people with disabilities. To address this gap in training, our medical school developed several strategies, including a session for second year medical students to address communication skills, knowledge, and attitudes relevant to delivering healthcare for people with disabilities. Here, our objective was to explore perceptions of people with spinal cord injury (SCI) who participated in the session on its content and structure. METHODS: Qualitative research using a focus group of people with SCI who participated in an educational session for medical students in an LCME accredited allopathic US medical school. A purposive sample of adults with SCI (N = 8) participated in a focus group. Data were analyzed using a six-phase thematic analysis. RESULTS: Participants favorably viewed the educational session, felt their participation was valuable, and had suggestions for its improvement. Four major themes were identified: (1) session format, content; (2) addressing student discomfort and avoidance behaviors; (3) increasing student knowledge and preparation; and (4): important lessons from discussions of past and role-played doctor-patient interactions. CONCLUSIONS: First-person input from people with SCI is critical to improve medical education and healthcare provision to the SCI community. To our knowledge, this is the first study to report feedback from stakeholders providing specific recommendations for teaching disabilities awareness to undergraduate medical students. We expect these recommendations to be relevant to the SCI and medical education communities in improving healthcare for people with SCI and other disabilities.

Profiling Immunological Phenotypes in Individuals During the First Year After Traumatic Spinal Cord Injury: A Longitudinal Analysis.

Abstract Individuals with SCI are severely affected by immune system changes, resulting in increased risk of infections and persistent systemic inflammation. While recent data support that immunological changes after SCI differ in the acute and chronic phases of living with SCI, only limited immunological phenotyping in humans is available. To characterize dynamic molecular and cellular immune phenotypes over the first year, we assess RNA (bulk-RNA sequencing), protein, and flow cytometry (FACS) profiles of blood samples from 12 individuals with SCI at 0-3 days and at 3, 6, and 12 months post injury (MPI) compared to 23 uninjured individuals (controls). We identified 967 differentially expressed (DE) genes in individuals with SCI (FDR <0.001) compared to controls. Within the first 6 MPI we detected a reduced expression of NK cell genes, consistent with reduced frequencies of CD56bright, CD56dim NK cells present at 12 MPI. Over 6MPI, we observed increased and prolonged expression of genes associated with inflammation (e.g. HMGB1, Toll-like receptor signaling) and expanded frequencies of monocytes acutely. Canonical T-cell related DE genes (e.g. FOXP3, TCF7, CD4) were upregulated during the first 6 MPI and increased frequencies of activated T cells at 3-12 MPI. Neurological injury severity was reflected in distinct whole blood gene expression profiles at any time after SCI, verifying a persistent 'neurogenic' imprint. Overall, 2876 DE genes emerge when comparing motor complete to motor incomplete SCI (ANOVA, FDR <0.05), including those related to neutrophils, inflammation, and infection. In summary, we identify a dynamic immunological phenotype in humans, including molecular and cellular changes which may provide potential targets to reduce inflammation, improve immunity, or serve as candidate biomarkers of injury severity.

Pressure injury prevalence and characteristics in patients with COVID-19 admitted to acute inpatient rehabilitation unit.

Objective: To investigate the incidence and severity of pressure injuries among COVID-19 patients who required acute hospitalization and subsequent acute inpatient rehabilitation (AIR). Design: Data was collected retrospectively from medical charts of COVID-19 patients who were admitted to AIR during April 2020-April 2021. Setting: Acute Inpatient Rehabilitation at a single hospital in the greater New York metropolitan area. Participants: Subjects included COVID-19 patients (N = 120) who required acute hospitalization and subsequent acute inpatient rehabilitation, of whom 39 (32.5%) had pressure injuries. Interventions: Not applicable. Main outcome measures: The incidence, location, and severity of pressure injuries in COVID-19 patients, as well as demographic and clinical characteristics of the acute hospitalization. Results: Among patients who developed pressure injuries, more patients received mechanical ventilation (59% vs. 33%, P < 0.05) and tracheostomy (67% vs. 17%, P < 0.00001). The lengths of stay were longer in both the intensive care unit (ICU) (34 vs. 15 days, P < 0.005), and in acute inpatient rehabilitation (22 vs. 17 days P < 0.05). Conclusion: Pressure injuries were more common in COVID-19 patients who had longer lengths of stay, received mechanical ventilation or tracheostomy, during acute hospitalization. This supports the use of protocols to prioritize pressure offloading in this patient population.

Macrophage Migration Inhibitory Factor (MIF) Makes Complex Contributions to Pain-Related Hyperactivity of Nociceptors after Spinal Cord Injury.

Neuropathic pain is a major, inadequately treated challenge for people with spinal cord injury (SCI). While SCI pain mechanisms are often assumed to be in the central nervous system, rodent studies have revealed mechanistic contributions from primary nociceptors. These neurons become chronically hyperexcitable after SCI, generating ongoing electrical activity (OA) that promotes ongoing pain. A major question is whether extrinsic chemical signals help to drive OA after SCI. People living with SCI exhibit acute and chronic elevation of circulating levels of macrophage migration inhibitory factor (MIF), a cytokine implicated in preclinical pain models. Probable nociceptors isolated from male rats and exposed to a MIF concentration reported in human plasma (1 ng/ml) showed hyperactivity similar to that induced by SCI, although, surprisingly, a ten-fold higher concentration failed to increase excitability. Conditioned behavioral aversion to a chamber associated with peripheral MIF injection suggested that MIF stimulates affective pain. A MIF inhibitor, Iso-1, reversed SCI-induced hyperexcitability. Unlike after SCI, acute MIF-induced hyperexcitability was only partially abrogated by inhibiting ERK signaling. Unexpectedly, MIF concentrations that induced hyperactivity in nociceptors from Naïve animals, after SCI induced a long-lasting conversion from a highly excitable nonaccommodating type to a rapidly accommodating, hypoexcitable type, possibly as a homeostatic response to prolonged depolarization. Treatment with conditioned medium from cultures of dorsal root ganglion (DRG) cells obtained after SCI was sufficient to induce MIF-dependent hyperactivity in neurons from Naïve rats. Thus, changes in systemic and DRG levels of MIF may help to maintain SCI-induced nociceptor hyperactivity that persistently promotes pain.Significance Statement:Chronic neuropathic pain is a major challenge for people with spinal cord injury (SCI). Pain can drastically impair quality of life, and produces substantial economic and social burdens. Available treatments, including opioids, remain inadequate. This study shows that the cytokine macrophage migration inhibitory factor (MIF) can induce pain-like behavior and plays an important role in driving persistent ongoing electrical activity in injury-detecting sensory neurons (nociceptors) in a rat SCI model. The results indicate that SCI produces an increase in MIF release within sensory ganglia. Low MIF levels potently excite nociceptors, but higher levels trigger a long-lasting hypoexcitable state. These findings suggest that therapeutic targeting of MIF in neuropathic pain states may reduce pain and sensory dysfunction by curbing nociceptor hyperactivity.

Activating Transcription Factor 3 (ATF3) is a Highly Conserved Pro-regenerative Transcription Factor in the Vertebrate Nervous System.

The vertebrate nervous system exhibits dramatic variability in regenerative capacity across species and neuronal populations. For example, while the mammalian central nervous system (CNS) is limited in its regenerative capacity, the CNS of many other vertebrates readily regenerates after injury, as does the peripheral nervous system (PNS) of mammals. Comparing molecular responses across species and tissues can therefore provide valuable insights into both conserved and distinct mechanisms of successful regeneration. One gene that is emerging as a conserved pro-regenerative factor across vertebrates is activating transcription factor 3 (ATF3), which has long been associated with tissue trauma. A growing number of studies indicate that ATF3 may actively promote neuronal axon regrowth and regeneration in species ranging from lampreys to mammals. Here, we review data on the structural and functional conservation of ATF3 protein across species. Comparing RNA expression data across species that exhibit different abilities to regenerate their nervous system following traumatic nerve injury reveals that ATF3 is consistently induced in neurons within the first few days after injury. Genetic deletion or knockdown of ATF3 expression has been shown in mouse and zebrafish, respectively, to reduce axon regeneration, while inducing ATF3 promotes axon sprouting, regrowth, or regeneration. Thus, we propose that ATF3 may be an evolutionarily conserved regulator of neuronal regeneration. Identifying downstream effectors of ATF3 will be a critical next step in understanding the molecular basis of vertebrate CNS regeneration.

Exploring the vagus nerve and the inflammatory reflex for therapeutic benefit in chronic spinal cord injury.

PURPOSE OF REVIEW: To describe features and implications of chronic systemic inflammation in individuals with spinal cord injury (SCI) and to summarize the growing therapeutic possibilities to explore the vagus nerve-mediated inflammatory reflex in this context. RECENT FINDINGS: The discovery of the inflammatory reflex provides a rationale to explore neuromodulation modalities, that is, electrical vagus nerve stimulation and pharmacological cholinergic modalities to regulate inflammation after SCI. SUMMARY: Inflammation in individuals with SCI may negatively impact functional recovery and medical consequences after SCI. Exploring the potential of the vagus nerve-based inflammatory reflex to restore autonomic regulation and control inflammation may provide a novel approach for functional improvement in SCI.