Depressive symptoms, pain, chronic medical morbidity, and interleukin-6 among primary care patients

Composite Biomarkers, Behavioral Symptoms, and Comorbidities in Axial Low Back Pain: A Systematic Review

PURPOSE

Proinflammatory cytokines play a critical role in chronic inflammation and pain and contribute to behavioral symptoms (depressive symptoms, anxiety, fatigue, sleep disturbance) and comorbidities (diabetes, cardiac diseases, cancer). Evidence is lacking on the specific proinflammatory cytokines associated with these behavioral symptoms/comorbidities co-occurring with axial low back pain (aLBP). This review aimed to systematically analyze the following: (1) specific proinflammatory cytokines associated with aLBP in adults, (2) associations among proinflammatory cytokines and behavioral symptoms in aLBP, and (3) relationships among proinflammatory cytokines and comorbidities in aLBP, to develop a new clinical framework for future diagnostic and intervention targets for patients with aLBP.

METHODS

Electronic databases, including PubMed/MEDLINE, ProQuest Nursing & Allied Health Source, and CINAHL Complete (EBSCO) were searched for the period January 2012 to February 2023. Eligible studies included cross-sectional, case-control, longitudinal, and cohort studies in which proinflammatory cytokines were reported in adults above 18 years with aLBP. Intervention studies and randomized controlled trails were excluded. The Joanna Briggs Institute (JBI) criteria were used for quality evaluation.

RESULTS

Findings from 11 studies showed 3 proinflammatory cytokines associated with pain intensity in adult patients with aLBP: C-Reactive Protein (CRP), Tumor Necrosis Factor (TNF-α), and Interleukin (IL-6). Some studies assessed associations between proinflammatory cytokines and depressive symptoms; none explored the association of proinflammatory cytokines with fatigue, anxiety, sleep disturbance, or comorbidities (diabetes, cardiac diseases, and cancer) in aLBP.

CONCLUSIONS

Proinflammatory cytokines in aLBP can serve as composite biomarkers for pain, associated symptoms, and comorbidities and may serve as a target for future interventions. There is need for well-designed studies assessing associations among chronic inflammation, behavioral symptoms, and comorbidities.

Common Pathways for Pain and Depression-Implications for Practice

BACKGROUND

Pain and depression have a high impact on caring for the people who need palliative care, but both of these are neglected compared with the approach for other symptoms encountered by these patients.

AREAS OF UNCERTAINTY

There are few studies in humans that support the existence of common neural circuits between depression and pain that also explore the use of drugs with effects in both conditions. More knowledge is needed about the relationship of these clinical entities that will lead to the optimization of the treatment and improvement of quality of life.

DATA SOURCES

We conducted a search in PubMed to identify relevant articles and reviews that have been published in the last 5 years, concerning the topic of common pathways between depression and pain (2014-April 2019).

THERAPEUTIC ADVANCES

The connections between the 2 clinical entities start at the level of the cortical regions. The hippocampus is the main site of neural changes, modification of the immune system, neuromodulators, neurotransmitters, and signaling pathways implicated in both conditions. Increased levels of peripheral proinflammatory cytokines and neuroinflammatory changes are related to the physiopathology of these entities. Inflammation links depression and pain by altering neural circuits and changes in their common cortical regions. Antidepressants are used to treat depression and chronic, pain but more experimental studies are needed to determine which antidepressant drugs are the most effective in treating the 2 entities.

CONCLUSIONS

Pharmacological and nonpharmacological interventions targeting cortical changes in pain and depression are promising, but more clinical studies are needed to validate their usefulness.

Biological Evaluation of Aegle marmelos Fruit Extract and Isolated Aegeline in Alleviating PainDepression Dyad: In Silico Analysis of Aegeline on MAO-A and iNOS

Pain and depression have been assessed to co-occur in up to 80% of patients, and this comorbidity is more debilitating and pricier for the patients as compared to either of these disorders alone. Aegle marmelos is a well-known medicinal plant with a broad spectrum of pharmacological activities. Aegeline is a relatively unexplored molecule present in Aegle marmelos. Therefore, the current investigation aims to explore the potential of Aegle marmelos fruit extract (AMFE) and isolated aegeline against the reserpine-induced pain-depression dyad. In the current investigation, aegeline was isolated from AMFE, followed by spectroscopic characterization, i.e., using NMR and mass analyses. AMFE (200 mg kg^-1 p.o) and aegeline (10 mg kg^-1 p.o.) were administered to reserpinized (0.5 mg kg^-1 s.c.) mice, and clorgyline (3 mg kg^-1 i.p.) was taken as the standard drug. AMFE and aegeline significantly alleviated the reserpine-induced reduction in a pain threshold and an increase in immobility as observed in behavioral tests of pain and depression, respectively. In silico molecular docking studies of aegeline showed a good binding interaction at the active sites of MAO-A and iNOS. The in vivo analysis showed that AMFE and aegeline treatment significantly decreased the monoamine oxidase-A (MAO-A) activity, serum interleukin-6 (IL-6) level, and lipid peroxidation, along with an increase in the reduced glutathione level in comparison to the reserpine-treated group. Immunofluorescence studies also showed that AMFE and aegeline abrogated the reserpine-induced increase in iNOS expression. Conclusively, the results delineate that AMFE and aegeline might exert a protective effect via downregulating the MAO-A hyperactivity, IL-6 level, oxidative and nitrosative stress.

Behavioral Symptom Clusters, Inflammation, and Quality of Life in Chronic Low Back Pain

BACKGROUND

Chronic low back pain is a prevalent condition, often involving an inflammatory process. Behavioral symptoms, including depressed mood, fatigue, and sleep disturbance, intensifies pain and reduces quality of life.

AIMS

The objectives of this pilot study were to identify behavioral symptom clusters (depressive mood, fatigue, poor sleep) in individuals with chronic low back pain, and to determine whether there are differences in pain, quality of life and inflammation (plasma IL-6) based on cluster membership.

DESIGN AND SETTINGS

A cross-sectional study was conducted in a pain clinic.

PARTICIPANTS/ SUBJECTS

Participants between ages 21 to 70 years (N=69) were enrolled if they had chronic low back pain for at least six months.

METHODS

Participants completed instruments measuring, pain, depressive mood, fatigue, sleep, and demographic form. Blood (10ml) was obtained. Latent class analysis was used to identify clusters.

RESULTS AND CONCLUSIONS

Findings revealed a two-class model, with Class 1 characterized by more depressive mood, fatigue, and sleep disturbance compared to Class 2. Class 1 participants reported worse quality of life than those in Class 2. Pain severity and pain interference were not significantly different between the classes. Levels of IL-6 were significantly greater in Class 1 participants compared to Class 2 with higher levels of IL-6 correlating with greater pain severity and sleep disturbances. Logistic regression revealed higher levels of IL-6 predicted Class 1 membership. Behavioral symptoms cluster exist in chronic low back pain patients and impact quality of life. Inflammation may contribute to relationship between behavioral symptoms and pain severity.

Cardiometabolic disease, depressive symptoms, and sleep disorders in middle-aged adults with functional disabilities: NHANES 2007-2014

Purpose: This study examined whether depressive symptoms and sleep disorders modified the association between functional disabilities and cardiometabolic disease profiles in middle-aged adults (40-64 years).Methods: Participants came from the 2007-2014 NHANES. Information regarding cardiometabolic diseases, demographics, depressive symptoms, and sleep disorders were obtained. Logistic regression analyses were performed with group as the exposure and cardiometabolic diseases as the response.Results: Adults with moderate (n = 550) and severe (n = 556) functional disabilities had a higher prevalence of cardiometabolic diseases, depressive symptoms, and sleep disorders compared to adults without functional disabilities (n = 3765; p < 0.05). After adjusting for demographics, the odds of cardiovascular disease and diabetes were higher in adults with severe functional disabilities (OR: 1.47 and 1.76, p < 0.05), but not in adults with moderate functional disabilities (OR: 1.21 and 1.22, p > 0.05). With further adjustment for depressive symptoms and sleep disorders, the odds of cardiovascular disease (OR: 1.47) and diabetes (OR: 1.76) remained increased (p < 0.05) in adults with severe functional disabilities.Conclusions: By middle-age, adults with functional disabilities have an elevated prevalence of cardiometabolic diseases, depressive symptoms, and sleep disorders compared to adults without functional disabilities. The elevated cardiometabolic disease profiles are present in adults with severe functional disabilities even after adjusting depressive symptoms and sleep disorders.IMPLICATIONS FOR REHABILITATIONIn the elderly population, cardiometabolic diseases, depression, and sleep disorders are prevalent conditions and are often co-morbid.In a nationally representative sample of middle-aged adults, study findings found that those with severe functional disabilities had an elevated cardiometabolic disease prevalence compared to adults without functional disabilities, even after accounting for the higher prevalence of depressive symptoms and sleep disorders.Earlier screening for cardiometabolic diseases, depression, and sleep disorders in adults with functional disabilities, or those who are at risk for developing functional disabilities, are warranted.Interventions pertaining to physical, pharmacological, or care coordination focused on improving cardiometabolic disease profiles among adults with functional disabilities are needed.

Low-grade inflammation may moderate the effect of behavioral treatment for chronic pain in adults

The purpose of the present pilot study was to explore the moderating role of basal inflammation on the effects of behavioral pain treatment in 41 patients with long-standing pain. Baseline pro-inflammatory status moderated behavioral treatment outcomes: higher pre-treatment levels of Tumor Necrosis Factor (TNF)-α and Interleukin (IL)-6 were related to less improvement in pain intensity, psychological inflexibility and in mental health-related quality of life. The treatment outcomes improved in the subgroup that had low levels of pro-inflammatory cytokines at baseline, while the subjects with higher pro-inflammatory status did not. Altogether, results indicate that low-grade inflammation may influence the behavioral treatment outcomes and provide a possible explanation of the heterogeneity in treatment response.

Interleukin-6 and tumor necrosis factor-α are associated with quality of life-related symptoms in pulmonary arterial hypertension

RATIONALE

Inflammation is associated with symptoms in many chronic illnesses; however, this link has not been established in pulmonary arterial hypertension.

OBJECTIVES

The objective of this study was to investigate the association between inflammatory markers and quality of life-related symptoms in patients with pulmonary arterial hypertension. We hypothesized that higher circulating IL-6 and tumor necrosis factor-α levels would be associated with worse quality of life-related symptoms.

METHODS

We performed a secondary analysis using baseline and 3-month assessments of 62 subjects in a clinical trial of aspirin and simvastatin to determine the association between plasma IL-6 and tumor necrosis factor-α levels and the Medical Outcomes Study Short Form-36 subscales (pain, vitality, mental health).

MEASUREMENTS AND MAIN RESULTS

The mean age was 49.7±13.4 years; 87% were female. Higher IL-6 levels were significantly associated with lower Medical Outcomes Study Short Form-36 subscale scores, indicating worse bodily pain, vitality, and mental health (all P<0.01). Higher tumor necrosis factor-α levels were significantly associated with increased bodily pain, but better mental health scores.

CONCLUSIONS

IL-6 and tumor necrosis factor-α levels are associated with certain quality of life domains in patients with pulmonary arterial hypertension. Clinical trial registered with www.clinicaltrials.gov (NCT00384865).

Comparison of pro-inflammatory cytokines among patients with bipolar disorder and unipolar depression and normal controls

OBJECTIVE

Research evidence has shown that bipolar disorder (BD) and unipolar depression (UD) are both related to inflammatory dysregulation, but few studies have compared the levels of cytokines between these two disorders.

METHODS

Study subjects were age- and gender-matched outpatients with BD or UD and normal controls (NC). Severities of depression and mania symptoms were assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Young Mania Rating Scale (YMRS). Pro-inflammatory cytokines, including soluble interleukin-6 receptor (sIL-6R), soluble interleukin-2 receptor (sIL-2R), C-reactive protein (CRP), soluble tumor necrosis factor receptor type 1 (sTNF-R1), soluble p-selectin receptor (sP-selectin), and monocyte chemotactic protein-1 (MCP-1), were assessed in all subjects by enzyme-linked immunosorbent assays.

RESULTS

In all, 130 patients with BD, 149 patients with UD, and 130 NC were enrolled in the study; 67.6% were female and the average age was mean ± standard deviation (SD) 43.5 ± 11.8 years. The BD group had a significantly higher smoking rate, more medical comorbidity, higher body mass index (BMI), and higher levels of sIL-2R, sIL-6R, CRP, sTNF-R1, and MCP-1 (all p < 0.01) than the UD and NC groups. When the remitted patients with BD (YMRS scores ≤ 12) were compared with the patients with UD, controlling for age, MADRS score, smoking, medical comorbidity, and BMI in the regression model, the results showed that the BD group had significantly higher levels of sIL-6R (p < 0.001), CRP (p = 0.045), sTNF-R1 (p = 0.036), and MCP-1 (p = 0.001) than the UD group.

CONCLUSIONS

Higher levels of sIL-6R, CRP, sTNF-R1, and MCP-1 were noted in BD than in UD. These results may suggest a more severe inflammatory dysregulation in BD. Further studies are required to investigate whether these cytokines could be biomarkers for affective disorders.