Mediating effect of depressive symptoms on the relationship of chronic pain and cardiovascular diseases among Chinese population: Evidence from the CHARLS

OBJECTIVE

Few studies have examined the direct or indirect effect of chronic pain on cardiovascular diseases (CVD) within Chinese population. The objective aimed to investigate the mediating role of depressive symptoms between chronic pain and CVD.

METHODS

6522 participants from China Health and Retirement Longitudinal Study were included in this retrospective cohort study. The main endpoint was the occurrence of CVD. Weighted multivariate logistic regression was used to assess the association between chronic pain and depressive symptoms. Distribution-of-product method was employed to examine the mediation effect of depressive symptoms. Subgroup analyses were performed.

RESULTS

219 developed CVD at the end of follow-up period. After adjusting all confounding variables, chronic pain was associated with increased risk of depressive symptoms in total population [odds ratio (OR) = 3.85, 95%confidence interval (CI): 3.35-4.42]. Among total population, there was a positive association of chronic pain and CVD [risk ratio (RR)a = 2.00, 95% CI: 1.33-3.00] (total effect). After further adjusting depressive symptoms, the association between chronic pain and CVD was significant (RRb = 1.67, 95% CI: 1.16-2.41) (direct effect). According to the distribution-of-product test, we observed a mediating effect of depressive symptoms on the relationship between chronic pain and CVD with the percentage of mediation of 32.8%. The mediating effect of depression was observed in individuals of aged45-65 years old, female participants, participants who never drinking and not have hypertension.

CONCLUSION

Chronic pain was positively associated with CVD for Chinese population, and depressive symptoms was considered to mediate the association between chronic pain and CVD.

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.

Inhibition of T-Type Calcium Channels With TTA-P2 Reduces Chronic Neuropathic Pain Following Spinal Cord Injury in Rats

Spinal cord injury (SCI)-induced neuropathic pain (SCI-NP) develops in up to 60 to 70% of people affected by traumatic SCI, leading to a major decline in quality of life and increased risk for depression, anxiety, and addiction. Gabapentin and pregabalin, together with antidepressant drugs, are commonly prescribed to treat SCI-NP, but their efficacy is unsatisfactory. The limited efficacy of current pharmacological treatments for SCI-NP likely reflects our limited knowledge of the underlying mechanism(s) responsible for driving the maintenance of SCI-NP. The leading hypothesis in the field supports a major role for spontaneously active injured nociceptors in driving the maintenance of SCI-NP. Recent data from our laboratory provided additional support for this hypothesis and identified the T-type calcium channels as key players in driving the spontaneous activity of SCI-nociceptors, thus providing a rational pharmacological target to treat SCI-NP. To test whether T-type calcium channels contribute to the maintenance of SCI-NP, male and female SCI and sham rats were treated with TTA-P2 (a blocker of T-type calcium channels) to determine its effects on mechanical hypersensitivity (as measured with the von Frey filaments) and spontaneous ongoing pain (as measured with the conditioned place preference paradigm), and compared them to the effects of gabapentin, a blocker of high voltage-activated calcium channels. We found that both TTA-P2 and gabapentin reduced mechanical hypersensitivity in male and females SCI rats, but surprisingly only TTA-P2 reduced spontaneous ongoing pain in male SCI rats. PERSPECTIVES: SCI-induced neuropathic pain, and in particular the spontaneous ongoing pain component, is notoriously very difficult to treat. Our data provide evidence that inhibition of T-type calcium channels reduces spontaneous ongoing pain in SCI rats, supporting a clinically relevant role for T-type channels in the maintenance of SCI-induced neuropathic pain.

Biomarkers mining for spinal cord injury based on integrated multi-transcriptome expression profile data

BACKGROUND

This study was aimed to discover more biomarkers associated with spinal cord injury (SCI) by constructing a competing endogenous RNA (ceRNA) network.

METHODS

The transcriptome expression profile data related to SCI (GSE45006 GSE20907) were downloaded from GEO database. The differentially expressed RNAs (DERs), including lncRNAs, miRNAs, and mRNAs, between SCI and control groups were selected, which were then performed function enrichment analyses. Following that, a SCI-related ceRNA regulatory network was constructed. PCA analysis was performed on the genes constituting the ceRNA regulatory network directly related to SCI.

RESULTS

In GSE45006 and GSE20907 datasets, there were respectively 3336 and 1453 DERs. Venn analysis showed that there were 429 DERs which had consistent differential expression direction. RGD1564534-miR-29b-5p relation pair and 103 miRNA-target regulatory pairs were integrated to construct the ceRNA regulatory network. Then a SCI-related ceRNA regulatory network including 8 mRNAs of IFNGR1, STAT2, CYBB, NFATC1, FCGR2B, HMOX1, TLR4, and HK2, a lncRNA of RGD1564534, and a miRNA of miR-29b-5p was constructed. Additionally, two pathways, osteoclast differentiation, and HIF-1 signaling pathway, were involved in this network. PCA indicated the samples before and after injury can be significantly distinguished based on the genes in the ceRNA network.

CONCLUSION

A total of 8 SCI-related mRNAs have been identified in the ceRNA network, including IFNGR1, STAT2, CYBB, NFATC1, FCGR2B, HMOX1, TLR4, and HK2. Moreover, RGD1564534 may serve as ceRNA by competitively binding to miR-29b-5p to regulate the expression of 8 SCI-related mRNAs. Therefore, these genes may serve as key biomarkers of SCI.

Neuropathic Low Back Pain and Burnout among Hungarian Workers

Burnout is an increasingly prevalent syndrome mainly involving those working in human services. Although it is categorized as an occupational phenomenon and not as a medical condition, it seems to be strongly associated with several diseases such as pain syndromes. However, no studies examined the association between neuropathic low back pain and burnout. This questionnaire-based study was carried out between April 2019 and March 2020 in three main sites among teachers, social workers and healthcare workers. Demographic criteria included age, gender, marital status, number of children, type of work, years spent with work, work schedule, legal relation, secondary employment. Included diseases were diabetes, hypertension, ischemic heart disease, generalized pain (pain involving more than one area of the body) and depression. Low back pain was assessed by the painDETECT questionnaire, burnout was measured with the Maslach Burnout Inventory (MBI) and depression was measured by the Beck Depression Inventory. Dysfunctional attitudes were also recorded. Overall, 1500 questionnaires were successfully delivered and 1141 responses received (response rate of 76%). Three hundred social workers, 399 teachers, 339 paramedics, 35 doctors and 68 medical attendants have completed our survey. In a multivariate analysis including of all factors (demographic criteria, burnout, depression, dysfunctional attitudes, comorbidity etc.) neuropathic low back pain was associated with age > 62 (OR = 3.981, p = 0.01), number of children ≥ 2 (OR = 2.638, p = 0.003), job type (being a social worker) (OR = 6.654, p < 0.001), burnout (OR = 2.577, p < 0.001), current depression (OR = 2.397, p < 0.001), and suffering from generalized pain (OR= 4.076, p < 0.001). This is the first study showing the association of burnout and neuropathic low back pain, which is the most common cause of disability. Based on our results neuropathic low back pain and burnout have similar risk factors and consequences which raises the possibility of similar pathophysiology.

Association of Secondary Health Conditions With Future Chronic Health Conditions Among Persons With Traumatic Spinal Cord Injury

BACKGROUND

Secondary health conditions (SHC) are physical and mental health conditions that are causally related to disabilities. Studies have found that SHC increase risk of negative health outcomes among people with traumatic spinal cord injury (TSCI). However, little has been done to assess the association of SHC with the risk of chronic health conditions (CHC) after TSCI.

OBJECTIVES

To identify the prevalence of CHC in adults with TSCI, changes in CHC at follow-up, and the associations of baseline SHC with future CHC.

METHODS

Participants included 501 adults with TSCI of at least 1-year duration, identified through a population-based surveillance system. Baseline and follow-up self-report assessments were completed. We measured seven SHC: fatigue, spasticity, pain, pressure ulcers, subsequent injury, fracture, and anxiety disorder, and measured seven CHC: diabetes, heart attack, coronary artery disease, stroke, cancer, hypertension, and high blood cholesterol. Control variables included gender, race/ethnicity, age at injury, years post injury, injury severity, smoking status, binge drinking, and taking prescription medication. We implemented a Poisson regression model for the multivariate analyses.

RESULTS

The total number of CHC, the percentage of participants having at least one CHC, and prevalence of three individual CHC (diabetes, cancer, and high cholesterol) increased from baseline to follow-up. After controlling for demographic, injury characteristics, and behavioral factors, pain interference and anxiety disorder at baseline were associated with the total number of CHC at follow-up.

CONCLUSION

CHC are common among adults with TSCI and increase significantly over time. Pain and anxiety disorders appear to be risk factors for future CHC.

Prevalence of chronic pain after spinal cord injury: a systematic review and meta-analysis

BACKGROUND

The reported prevalence of chronic pain after spinal cord injury (SCI) varies widely due, in part, to differences in the taxonomy of chronic pain. A widely used classification system is available to describe subcategories of chronic pain in SCI, but the prevalence of chronic pain in SCI based on this system is unknown.

OBJECTIVE

The primary objective of this systematic review and meta-analysis is to determine the prevalence of chronic pain after SCI based on the International Spinal Cord Injury Pain (ISCIP) classification system.

EVIDENCE REVIEW

A comprehensive search of databases from January 1980 to August 2019 was conducted. The risk of bias was assessed using a modified tool developed for uncontrolled studies. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess certainty in prevalence estimates.

FINDINGS

A total of 1305 records were screened, and 37 studies met inclusion criteria. The pooled prevalence of overall chronic pain was 68% (95% CI 63% to 73%). The pooled prevalence of neuropathic pain in 13 studies was 58% (95% CI 49% to 68%); the pooled prevalence of musculoskeletal pain in 11 studies was 56% (95% CI 41% to 70%); the pooled prevalence of visceral pain in 8 studies was 20% (95% CI 11% to 29%) and the pooled prevalence of nociceptive pain in 2 studies was 45% (95% CI 13% to 78%). Meta-regression of risk of bias (p=0.20), traumatic versus non-traumatic etiology of injury (p=0.59), and studies where pain was a primary outcome (p=0.32) demonstrated that these factors were not significant moderators of heterogeneity. Certainty in prevalence estimates was judged to be low due to unexplained heterogeneity.

CONCLUSION

This systematic review and meta-analysis extends the findings of previous studies by reporting the prevalence of chronic pain after SCI based on the ISCIP classification system, thereby reducing clinical heterogeneity in the reporting of pain prevalence related to SCI.

Contribution of T-Type Calcium Channels to Spinal Cord Injury-Induced Hyperexcitability of Nociceptors

A hyperexcitable state and spontaneous activity of nociceptors have been suggested to play a critical role in the development of chronic neuropathic pain following spinal cord injury (SCI). In male rats, we employed the action potential-clamp technique to determine the underlying ionic mechanisms responsible for driving SCI-nociceptors to a hyperexcitable state and for triggering their spontaneous activity. We found that the increased activity of low voltage activated T-type calcium channels induced by the injury sustains the bulk (∼60-70%) of the inward current active at subthreshold voltages during the interspike interval in SCI-nociceptors, with a modest contribution (∼10-15%) from tetrodotoxin (TTX)-sensitive and TTX-resistant sodium channels and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. In current-clamp recordings, inhibition of T-type calcium channels with 1 μm TTA-P2 reduced both the spontaneous and the evoked firing in response to current injections in SCI-nociceptors to a level similar to sham-nociceptors. Electrophysiology in vitro was then combined with the conditioned place preference (CPP) paradigm to determine the relationship between the increased activity of T-type channels in SCI-nociceptors and chronic neuropathic pain following SCI. The size of the interspike T-type calcium current recorded from nociceptors isolated from SCI rats showing TTA-P2-induced CPP (responders) was ∼6 fold greater than the interspike T-type calcium current recorded from nociceptors isolated from SCI rats without TTA-P2-induced CPP (non-responders). Taken together, our data suggest that the increased activity of T-type calcium channels induced by the injury plays a primary role in driving SCI-nociceptors to a hyperexcitable state and contributes to chronic neuropathic pain following SCI.SIGNIFICANCE STATEMENT Chronic neuropathic pain is a major comorbidity of spinal cord injury (SCI), affecting up to 70-80% of patients. Anticonvulsant and tricyclic antidepressant drugs are first line analgesics used to treat SCI-induced neuropathic pain, but their efficacy is very limited. A hyperexcitable state and spontaneous activity of SCI-nociceptors have been proposed as a possible underlying cause for the development of chronic neuropathic pain following SCI. Here, we show that the increased activity of T-type calcium channels induced by the injury plays a major role in driving SCI-nociceptors to a hyperexcitable state and for promoting their spontaneous activity, suggesting that T-type calcium channels may represent a pharmacological target to treat SCI-induced neuropathic pain.

Dementia, Depression, and Associated Brain Inflammatory Mechanisms after Spinal Cord Injury

Evaluation of the chronic effects of spinal cord injury (SCI) has long focused on sensorimotor deficits, neuropathic pain, bladder/bowel dysfunction, loss of sexual function, and emotional distress. Although not well appreciated clinically, SCI can cause cognitive impairment including deficits in learning and memory, executive function, attention, and processing speed; it also commonly leads to depression. Recent large-scale longitudinal population-based studies indicate that patients with isolated SCI (without concurrent brain injury) are at a high risk of dementia associated with substantial cognitive impairments. Yet, little basic research has addressed potential mechanisms for cognitive impairment and depression after injury. In addition to contributing to disability in their own right, these changes can adversely affect rehabilitation and recovery and reduce quality of life. Here, we review clinical and experimental work on the complex and varied responses in the brain following SCI. We also discuss potential mechanisms responsible for these less well-examined, important SCI consequences. In addition, we outline the existing and developing therapeutic options aimed at reducing SCI-induced brain neuroinflammation and post-injury cognitive and emotional impairments.

Modulation of P2Y11-related purinergic signaling in inflammation and cardio-metabolic diseases

Chronic inflammation is the hallmark of cardiovascular pathologies with a major role in both disease progression and occurrence of long-term complications. The massive release of ATP during the inflammatory process activates various purinergic receptors, including P2Y11. This receptor is less studied but ubiquitously expressed in all cells relevant for cardiovascular pathology: cardiomyocytes, fibroblasts, endothelial and immune cells. While several studies suggested a potential pro-inflammatory role for P2Y11 receptors, recent literature data are supportive of an anti-inflammatory profile characterized by the immunosuppression of dendritic cells, inhibition of fibroblast proliferation and of cytokines and ATP secretion. Moreover, modulation of its activity appears to mediate the positive inotropic effect of ATP and mitigate endothelial dysfunction, thus rendering this receptor a promising therapeutic target in the cardiovascular disease armamentarium. The aim of the present review is to summarize the current available knowledge on P2Y11-related purinergic signaling in the setting of inflammation and cardio-metabolic diseases.

MicroRNAs in contusion spinal cord injury: pathophysiology and clinical utility

Spinal cord injury (SCI) in humans is a common central nervous system trauma. Pathophysiologically, SCI involves both primary and secondary damages. Therapeutically, targeting secondary damage including inflammation, neuropathic pain, apoptosis, demyelination, and glial reaction to promote functional benefits for SCI patients has long been considered a potential treatment strategy by neuroscientists and clinicians. As a type of small non-coding RNA, microRNAs (miRNAs) have been shown to play essential roles in the regulation of pathophysiologic processes of SCI and are considered to be an effective treatment method for SCI. Dysregulated expression of miRNAs is observed in SCI patients and animal models of SCI. Furthermore, miRNAs might also be used as biomarkers for diagnostic and prognostic purposes in SCI. Given contusion injury is the most clinically relevant type of SCI, this review mainly focuses on the role of miRNAs in the pathophysiology of contusion SCI and the putative utilization of miRNAs as diagnostic biomarkers and therapeutic targets for contusion SCI.

Pain Prevalence and Pain Management in a Chinese Hospital

Background

Pain prevalence has been investigation in many developed countries, but integrated information about pain prevalence in Chinese hospitals is lacking. To achieve better pain treatment of hospitalized patients, pain management needs to be investigated. The present descriptive and cross-sectional study was performed to demonstrate the prevalence of pain by comparison with the 4 traditional vital signs, and to investigate pain management in a Chinese teaching hospital.

Material/Methods

Structured and systematic interviews were undertaken by independent researchers. During a patient’s hospitalization, the prevalence of pain and the 4 vital signs were recorded. Then, the catalog, severity, causes, duration of pain, and pain management were assessed.

Results

We found: (1) 63.36% of patients (3248 in total) suffered from pain while in hospital, which was 1.8~2.8 times higher than the prevalence of abnormality of the 4 vital signs. (2) 76% of patients had moderate pain and 21.98% had severe pain. (3) Pain intensity differed among patients with different diseases, but did not differ by demographic factors. (4) Acute and chronic pain were present in 68% and 26% of patients, respectively. In addition, 16% of the patients had neuropathic pain. (5) More than half of the patients with pain refused to receive pain-relief medication because they worried about addiction to opioids and the adverse effects of analgesics. (6) Most medical staff properly understood the 3 ladder analgesics.

Conclusions

The prevalence of pain is higher than the abnormality of the 4 traditional vital signs in a Chinese hospital. Although pain management has broadly improved, more patient education is necessary.

Bioinformatic Analysis of Potential Biomarkers for Spinal Cord-injured Patients with Intractable Neuropathic Pain

BACKGROUND

Neuropathic pain is one of the common complications after spinal cord injury (SCI), affecting individuals' quality of life. The molecular mechanism for neuropathic pain after SCI is still unclear. We aimed to discover potential genes and microRNAs (miRNAs) related to neuropathic pain by the bioinformatics method.

METHODS

Microarray data of GSE69901 were obtained from Gene Expression Omnibus (GEO) database. Peripheral blood samples from individuals with or without neuropathic pain after SCI were collected. Twelve samples from individuals with neuropathic pain and 13 samples from individuals without pain as controls were included in the downloaded microarray. Differentially expressed genes (DEGs) between the neuropathic pain group and the control group were detected using the GEO2R online tool. Functional enrichment analysis of DEGs was performed using the DAVID database. Protein-protein interaction network was constructed from the STRING database. MiRNAs targeting these DEGs were obtained from the miRNet database. A merged miRNA-DEG network was constructed and analyzed with Cytoscape software.

RESULTS

In total, 1134 DEGs were identified between individuals with or without neuropathic pain (case and control), and 454 biological processes were enriched. We identified 4 targeted miRNAs, including mir-204-5p, mir-519d-3p, mir-20b-5p, mir-6838-5p, which may be potential biomarkers for SCI patients.

CONCLUSION

Protein modification and regulation of the biological process of the central nervous system may be a risk factor in SCI. Certain genes and miRNAs may be potential biomarkers for the prediction of and potential targets for the prevention and treatment of neuropathic pain after SCI.

Is neuropathic pain associated with cardiac sympathovagal activity changes in patients with breast cancer?

Objective Heart rate variability (HRV) is a good indicator of the autonomic nervous system (ANS) activity. A few studies have been conducted recently and have shown a relationship between reduced HRV and conditions that lead to neuropathic pain (NP). In this study, we aimed to investigate whether NP is associated with changes in cardiac sympathovagal activity in patients with breast cancer (BC). Methods We used the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) questionnaire to evaluate NP in 70 patients with BC. The patients were subjected to a 24-h Holter ECG monitorization to determine heart rate variability (HRV). Standard deviation (SD) of the normal-to-normal RR intervals (SDNN), SD of the mean of the RR intervals (SDAAN), mean of the SD of the NN interval (SDNN Index), low-frequency component/high-frequency component ratio (LF/HF), and the mean heart rate of the patients were recorded. Results According to the LANSS questionnaire, 18 (25.7%) of the patients were classified as NP (+). The SDNN (P = 0.001), SDAAN (P = 0.003), and SDDN index (P = 0.007) were significantly lower in patients with NP than in patients without NP, whereas LF/HF ratio (P = 0.000) and mean heart rate were found to be significantly higher in patients with NP (P = 0.006). Conclusion According to our findings, NP (+) patients with BC had increased cardiac sympathetic activity, which was suggested to be associated with increased cardiovascular morbidity and mortality.

Chronic disruptive pain in emerging adults with and without chronic health conditions and the moderating role of psychiatric disorders: Evidence from a population-based cross-sectional survey in Canada

BACKGROUND AND AIMS

There has been a growth in the proportion of emerging adults vulnerable to pain-related sequelae of chronic health conditions (CHCs). Given the paucity of research during this important developmental period, this study investigated the association between CHCs and chronic disruptive pain among emerging adults and the extent to which psychiatric disorders moderate this association.

METHODS

Data come from the 2012 Canadian Community Health Survey - Mental Health (CCHS-MH). This cross-sectional survey included 5987 participants that were 15-30 years of age and self-reported their CHCs (n=2460, 41%) and the extent to which pain impacted daily functioning using items from the Health Utilities Index Mark 3 (HUI 3). Group comparisons between respondents with CHCs and healthy controls were made using chi-square tests. Odds ratios (OR) and 95% confidence intervals (CI) were computed from ordinal logistic regression models adjusting for sociodemographic covariates. Product-term interactions between CHCs and psychiatric disorders were included in the models to explore moderating effects. All analyses were weighted to maintain representativeness of the study sample to the Canadian population.

RESULTS

The mean age of participants was 23.5 (SE 0.1) years and 48% were female. Compared to healthy controls, a greater proportion of participants with CHCs reported having chronic pain (20.3% vs. 4.5%, p<0.001). Among those with chronic pain, respondents with CHCs reported a greater number of activities prevented because of chronic disruptive pain (χ²=222.28, p<0.001). Similarly, in logistic regression models, participants with CHCs had greater odds of reporting chronic disruptive pain (OR=4.94, 95% CI=4.08-5.99). Alcohol (β=-0.66; p=0.025) and drug abuse/dependence disorders (β=-1.24; p=0.012) were found to moderate the association between CHCs and chronic disruptive pain. Specifically, the probability of chronic disruptive pain was higher for emerging adults without CHCs and with alcohol or drug disorders; however, among participants with CHCs, probability was higher for those without these disorders.

CONCLUSIONS

There is a robust association between CHCs and chronic disruptive pain. The moderating effects suggest that alcohol or drug disorders are especially harmful for emerging adults without CHCs and contribute to higher levels of chronic disruptive pain; however, among those with CHCs, alcohol and illicit drugs may be used as a numbing agent to blunt chronic disruptive pain.

IMPLICATIONS

Findings from this study have implications for the integration and coordination of services to design strategies aimed at managing chronic disruptive pain and preventing pain-related disabilities later in life. Within the health system, healthcare providers should engage in dialogues about mental health and substance use regularly with emerging adults, be proactive in screening for psychiatric disorders, and continue to monitor the impact of pain on daily functioning. Given the age range of emerging adults, there is tremendous opportunity for clinicians to work cooperatively with colleagues in the education system to support emerging adults with and without CHCs. Overall, clinicians, researchers, educators, and those in social services should continue to be mindful of the complex interrelationships between physical and mental health and chronic disruptive pain and work cooperatively to optimize health outcomes and prevent pain-related disabilities among emerging adults.

Inflammatory Stress Effects on Health and Function After Spinal Cord Injury

Background: Injury to the spinal cord produces immediate, adaptive inflammatory responses that can exacerbate the initial injury and lead to secondary damage. Thus far, researchers and clinicians have focused on modulating acute inflammation to preserve sensorimotor function. However, this singular approach risks overlooking how chronic inflammation negatively impacts the broader health of persons with a spinal cord injury (SCI). Objective: The aim of this monograph was to discuss interrelated processes causing persistent inflammatory stress after SCI, along with associated health risks. We review archetypal factors that contribute to a chronic inflammatory state, including response to injury, acute infection, and autonomic dysreflexia. Secondary complications producing and exacerbating inflammation are also discussed, including pain, depression, obesity, and injury to the integumentary and skeletal systems. Finally, we discuss the role of bacteria and the gut microbiome in this process and then conclude with a discussion on how a pro-inflammatory phenotype promotes an elevated risk for cardiovascular disease after injury. Conclusions: Effectively managing chronic inflammation should be a high priority for clinicians and researchers who seek to improve the health and life quality of persons with SCI. Chronic inflammation worsens secondary medical complications and amplifies the risk for cardiometabolic disorders after injury, directly impacting both the quality of life and mortality risk after SCI. Inflammation can worsen pain and depression and even hinder neurological recovery. It is, therefore, imperative that countermeasures to chronic inflammation are routinely considered from the point of initial injury and proceeding throughout the lifespan of the individual with SCI.

Neuropathic pain following traumatic spinal cord injury: Models, measurement, and mechanisms

Neuropathic pain following spinal cord injury (SCI) is notoriously difficult to treat and is a high priority for many in the SCI population. Resolving this issue requires animal models fidelic to the clinical situation in terms of injury mechanism and pain phenotype. This Review discusses the means by which neuropathic pain has been induced and measured in experimental SCI and compares these with human outcomes, showing that there is a substantial disconnection between experimental investigations and clinical findings in a number of features. Clinical injury level is predominantly cervical, whereas injury in the laboratory is modeled mainly at the thoracic cord. Neuropathic pain is primarily spontaneous or tonic in people with SCI (with a relatively smaller incidence of allodynia), but measures of evoked responses (to thermal and mechanical stimuli) are almost exclusively used in animals. There is even the question of whether pain per se has been under investigation in most experimental SCI studies rather than simply enhanced reflex activity with no affective component. This Review also summarizes some of the problems related to clinical assessment of neuropathic pain and how advanced imaging techniques may circumvent a lack of patient/clinician objectivity and discusses possible etiologies of neuropathic pain following SCI based on evidence from both clinical studies and animal models, with examples of cellular and molecular changes drawn from the entire neuraxis from primary afferent terminals to cortical sensory and affective centers. © 2016 Wiley Periodicals, Inc.

Coronary artery disease and hypertension in a non-selected spinal cord injury patient population

STUDY DESIGN

Retrospective observational comparative study.

OBJECTIVES

The objectives of this study were to assess the atherosclerosis diseases and risk factors prevalence after spinal cored injury (SCI).

SETTING

Loewenstein Rehabilitation Hospital, Israel.

METHODS

Data of 154 traumatic and non-traumatic SCI patients were retrospectively collected. Coronary artery disease (CAD), myocardial infarction (MI), hypertension (HT) and risk factors for atherosclerotic diseases were examined after SCI for prevalence and effects, and compared with published corresponding data of the general population.

RESULTS

CAD, MI and HT were found in 11.7, 6.7 and 29.2% of 120 patients, aged 53.4±11.1 years, 83.3% males, who survived until the end of the follow-up. Corresponding values for the general population, adjusted for age, gender and years of education, are 8.5, 6.6 and 24.9% in Israel, and 10.2% for CAD and 40.3% for HT, in US. Body mass index>30 increased the odds of acquiring CAD (P=0.016). Hypercholesterolemia and older age at injury increased the hazard for HT (P=0.044; P=0.019, respectively). A steady partner decreased the risk of CAD (P=0.029). HT was more prevalent at T₄-T₆ than above T₄ (52 vs 23.3%, P=0.02). Patients with SCI below T₆ had a higher rate of diabetes mellitus, hypercholesterolemia, and past smoking, and fewer years of education than those with SCI above T₇ (P=0.016; P=0.032; P=0.034; P=0.014, respectively).

CONCLUSION

The prevalence of CAD, HT and some of their risk factors after SCI is generally, but not consistently and not statistically significant, slightly higher than in the corresponding general population. The challenge is to reduce the prevalence of atherosclerotic morbidity after SCI below that in the general population.

Neuromuscular Electrical Stimulation-Induced Resistance Training After SCI: A Review of the Dudley Protocol

BACKGROUND

Neuromuscular electrical stimulation (NMES), often referred to as functional electrical stimulation (FES), has been used to activate paralyzed skeletal muscle in people with spinal cord injury (SCI). The goal of NMES has been to reverse some of the dramatic losses in skeletal muscle mass, to stimulate functional improvements in people with incomplete paralysis, and to produce some of the health benefits associated with exercise.

OBJECTIVE

The purpose of this brief review is to describe a quantifiable resistance training form of NMES developed by Gary A. Dudley.

METHODS

People with motor complete SCI were first tested to confirm that an NMES-induced muscle contraction of the quadriceps muscle could be achieved. The contraction stimulus consisted of biphasic pulses at 35 Hz performed with increasing current up to what was needed to produce full knee extension. Four sets of 10 knee extensions were elicited, if possible. Training occurred biweekly for 3 to 6 months, with ankle weights being increased up to an added weight of 9.1 kg if the 40 repetitions could be performed successfully for 2 sessions.

RESULTS

Many participants have performed this protocol without adverse events, and all participants showed progression in the number of repetitions and/or the amount of weight lifted. Large increases in muscle mass occur, averaging 30% to 40%. Additional physiological adaptations to stimulated muscle have also been reported.

CONCLUSIONS

These results demonstrate that the affected skeletal muscle after SCI responds robustly to progressive resistance training many years after injury. Future work with NMES should determine whether gains in lean mass translate to improved health, function, and quality of life.

Severity of Depression, Anxious Distress and the Risk of Cardiovascular Disease in a Swedish Population-Based Cohort

Background

Depression is known to be associated with cardiovascular diseases (CVD). This population-based cohort study aimed to determine the association between depression of varying severity and risk for CVD and to study the effect of concomitant anxious distress on this association.

Methods

We utilized data from a longitudinal cohort study of mental health, work and relations among adults (20–64 years), with a total of 10,443 individuals. Depression and anxious distress were assessed using psychiatric rating scales and defined according to DSM-5. Outcomes were register-based and self-reported cardiovascular diseases.

Findings

Overall increased odds ratios of 1.5 to 2.6 were seen for the different severity levels of depression, with the highest adjusted OR for moderate depression (OR 2.1 (95% CI 1.3, 3.5). Similar odds ratios were seen for sub-groups of CVD: ischemic/hypertensive heart disease and stroke, 2.4 (95% CI 1.4, 3.9) and OR 2.1 (95%CI 1.2, 3.8) respectively. Depression with anxious distress as a specifier of severity showed OR of 2.1 (95% CI 1.5, 2.9) for CVD.

Conclusion

This study found that severity level of depression seems to be of significance for increased risk of CVD among depressed persons, although not in a dose-response manner which might be obscured due to treatment of depression. Further, we found a higher risk of CVD among depressed individuals with symptoms of anxious distress.