Is There an Association Between Markers of Cardiovascular Autonomic Dysfunction at Discharge From Rehabilitation and Participation 1 and 5 Years Later in Individuals With Spinal Cord Injury?

Autonomic Cardiovascular Control, Psychological Well-Being, and Cognitive Performance in People With Spinal Cord Injury

PURPOSE

To examine associations between parameters of psychological well-being, injury characteristics, cardiovascular autonomic nervous system (ANS) control, and cognitive performance in persons with spinal cord injury (SCI) compared with age-matched uninjured controls. This is an observational, cross-sectional study including a total of 94 participants (52 with SCI and 42 uninjured controls: UIC). Cardiovascular ANS responses were continuously monitored at rest and during administration of the Paced Auditory Serial Addition Test (PASAT). Self-report scores on the SCI-Quality of Life questionnaires are reported for depression, anxiety, fatigue, resilience, and positive affect. Participants with SCI performed significantly more poorly on the PASAT compared with the uninjured controls. Although not statistically significant, participants with SCI tended to report more psychological distress and less well-being than the uninjured controls. In addition, when compared with uninjured controls, the cardiovascular ANS responses to testing were significantly altered in participants with SCI; however, these responses to testing did not predict PASAT performance. Self-reported levels of anxiety were significantly related to PASAT score in the SCI group, but there was no significant relationship between PASAT and the other indices of SCI-Quality of Life. Future investigations should more closely examine the relationship among cardiovascular ANS impairments, psychological disorders, and cognitive dysfunction to better elucidate the underpinnings of these deficits and to guide interventions aimed at improving physiological, psychological, and cognitive health after SCI. Tetraplegia, paraplegia, blood pressure variability, cognitive, mood.

Relationships between cardiovascular disease risk, neuropathic pain, mental health, and autonomic function in chronic spinal cord injury

STUDY DESIGN

Multicentre, cross-sectional study.

OBJECTIVES

To determine if clinical measures of poor mental health (MH-) and neuropathic pain (NP) are related to increased CVD risk in individuals with chronic spinal cord injury (SCI), and further elucidate the relationships between CVD risk, autonomic function, NP, and MH-.

SETTING

Eight SCI rehabilitation centres in the Netherlands.

METHODS

Individuals (n = 257) with a traumatic, chronic (≥10 yrs) SCI, with age at injury between 18-35 years, completed a self-report questionnaire and a one-day visit to a rehabilitation centre for testing. CVD risk was calculated using Framingham risk score. NP was inferred using The Douleur Neuropathique 4 clinical examination, and MH- was assessed using the five-item Mental Health Inventory questionnaire. Cardiovascular autonomic function was determined from peak heart rate during maximal exercise (HRpeak).

RESULTS

There was a high prevalence of both NP (39%) and MH- (45%) following SCI. MH- was significantly correlated with an adverse CVD risk profile (r = 0.174; p = 0.01), increased the odds of adverse 30-year CVD risk by 2.2 (CI 0.92-2.81, p = 0.02), and is an important variable in determining CVD risk (importance=0.74, p = 0.05). Females (p = 0.05) and those with a higher HRpeak (p = 0.046) tended to be more likely to have NP.

CONCLUSIONS

Clinical measures of MH-, but not NP, are important factors for increased CVD risk following SCI. NP tended to be more prevalent in those with more preserved cardiovascular autonomic function. The interrelationships between secondary consequences of SCI are complex and need further exploration.

Evaluation of Cardiovascular Autonomic Function during Inpatient Rehabilitation following Traumatic Spinal Cord Injury

Assessment of the degree of impaired autonomic nervous system (ANS) function is not part of routine clinical practice during inpatient rehabilitation following traumatic spinal cord injury (SCI). The goal of this investigation was to determine the utility of the International Standards for Neurologic Classification of SCI (ISNCSCI) and the recently revised International Standards to document remaining Autonomic Function after SCI (ISAFSCI) in documenting cardiovascular ANS impairment during inpatient rehabilitation following traumatic SCI. Beat-to-beat recording of supine heart rate (HR) and blood pressure (BP) were collected at the bedside for estimation of total cardiovascular ISAFSCI score, cardio-vagal modulation (i.e., high frequency HR variability [HFHRV]) and sympathetic vasomotor regulation (i.e., Mayer wave component of systolic BP [SBPmayer]). A total of 41 participants completed baseline testing, which was conducted 11 ± 5 days from the admission ISNCSCI examination. There were no differences in supine HR or BP based on the ISNCSCI or ISAFSCI assessments. The HFHRV was generally lower with more distal lesions (r2 = 0.15; p = 0.01), and SBPmayer was significantly lower in those with American Spinal Injury Association Impairment Scale (AIS) A compared with AIS B, C, D (Cohen's d = -1.4; p < 0.001). There were no significant differences in HFHRV or SBPmayer in patients with or without ISAFSCI evidence of cardiovascular ANS impairment. These preliminary data suggest that neither the ISNCSCI nor the ISAFSCI are sensitive to changes in ANS cardiovascular function following traumatic SCI. Bedside assessment of HR and BP variabilities may provide insight, but are not readily available in the clinical setting. Further research is required to evaluate methods that accurately assess the degree of ANS impairment following traumatic SCI.

Evaluation of cardiovascular disease risk in individuals with chronic spinal cord injury

STUDY DESIGN

Multicentre, cross-sectional study.

OBJECTIVES

To identify which markers of obesity, injury characteristics and autonomic function variables are related to cardiovascular disease (CVD) risk after spinal cord injury (SCI), and establish cut-points for detection and risk management.

SETTING

Eight SCI rehabilitation centres in the Netherlands.

METHODS

Individuals (n = 257) with a traumatic, chronic (≥10 years) SCI, with age at injury between 18 and 35 years, completed a self-report questionnaire and a one-day visit to a rehabilitation centre for testing. Three anthropometric measures were tested: body mass index (BMI); waist circumference (WC); and waist-to-height ratio (WHtR). Injury characteristics included: American Spinal Injury Association impairment scale (AIS); duration of injury (DOI); and neurological level of injury (LOI). Cardiovascular autonomic function was assessed from peak heart rate during maximal exercise (HR_peak). Systolic arterial pressure (SAP) and aerobic capacity (VO_2peak) were also determined. CVD risk was calculated using the Framingham risk score (FRS).

RESULTS

All anthropometric variables were associated with FRS, with WC showing the strongest correlation (r = 0.41, p < 0.001) and greatest area under the curve (0.73) for 10-year CVD risk (%). WC, DOI, SAP, HR_peak, LOI, and VO_2peak (variable importance: 0.81, 1.0, 0.98, 0.98, 0.66, 0.68, respectively) were important predictive variables for 10-year CVD risk in individuals with SCI.

CONCLUSIONS

We confirm that WC is a simple, practical measure of CVD risk, and along with DOI and markers of cardiovascular autonomic function, plays a role in the increased CVD risk following SCI.

Cell cycle and complement inhibitors may be specific for treatment of spinal cord injury in aged and young mice: Transcriptomic analyses

Previous studies have reported age-specific pathological and functional outcomes in young and aged patients suffering spinal cord injury, but the mechanisms remain poorly understood. In this study, we examined mice with spinal cord injury. Gene expression profiles from the Gene Expression Omnibus database (accession number GSE93561) were used, including spinal cord samples from 3 young injured mice (2-3-months old, induced by Impactor at Th9 level) and 3 control mice (2-3-months old, no treatment), as well as 2 aged injured mice (15-18-months old, induced by Impactor at Th9 level) and 2 control mice (15-18-months old, no treatment). Differentially expressed genes (DEGs) in spinal cord tissue from injured and control mice were identified using the Linear Models for Microarray data method, with a threshold of adjusted P < 0.05 and |logFC(fold change)| > 1.5. Protein-protein interaction networks were constructed using data from the STRING database, followed by module analysis by Cytoscape software to screen crucial genes. Kyoto encyclopedia of genes and genomes pathway and Gene Ontology enrichment analyses were performed to investigate the underlying functions of DEGs using Database for Annotation, Visualization and Integrated Discovery. Consequently, 1,604 and 1,153 DEGs were identified between injured and normal control mice in spinal cord tissue of aged and young mice, respectively. Furthermore, a Venn diagram showed that 960 DEGs were shared among aged and young mice, while 644 and 193 DEGs were specific to aged and young mice, respectively. Functional enrichment indicates that shared DEGs are involved in osteoclast differentiation, extracellular matrix-receptor interaction, nuclear factor-kappa B signaling pathway, and focal adhesion. Unique genes for aged and young injured groups were involved in the cell cycle (upregulation of PLK1) and complement (upregulation of C3) activation, respectively. These findings were confirmed by functional analysis of genes in modules (common, 4; aged, 2; young, 1) screened from protein-protein interaction networks. Accordingly, cell cycle and complement inhibitors may be specific treatments for spinal cord injury in aged and young mice, respectively.