Cerebral functional deficits in patients with ankylosing spondylitis- an fMRI study

Causal associations between common musculoskeletal disorders and dementia: a Mendelian randomization study

Introduction

Dementia and musculoskeletal disorders (MSDs) are major public health problems. We aimed to investigate the genetic causality of common MSDs and dementia.

Methods

Two-sample Mendelian randomization (MR) was used in this study. MR analysis based on gene-wide association study (GWAS) data on osteoarthritis (OA), dementia with Lewy bodies, and other MSDs and dementia types were obtained from the Genetics of Osteoarthritis consortium, IEU-open GWAS project, GWAS catalog, and FinnGen consortium. Rigorously selected single-nucleotide polymorphisms were regarded as instrumental variables for further MR analysis. Inverse-variance weighted, MR-Egger regression, weight median, simple mode, and weight mode methods were used to obtain the MR estimates. Cochran's Q test, MR-Egger and MR-Pleiotropy Residual Sum and Outlier analysis, and the leave-one-out test were applied for sensitivity testing.

Results

The inverse-variance weighted method showed that hip OA was genetically associated with a lower risk of dementia, unspecified dementia, dementia in Alzheimer's disease, and vascular dementia. Kneehip OA was inversely associated with unspecified dementia and vascular dementia. Rheumatoid arthritis, juvenile idiopathic arthritis and seronegative rheumatoid arthritis were inversely associated with frontotemporal dementia, and rheumatoid arthritis was inversely associated with unspecified dementia. Simultaneously, ankylosing spondylitis was an independent risk factor for dementia, dementia with Lewy bodies, and dementia in Alzheimer's disease. Sensitivity tests showed that heterogeneity and horizontal pleiotropy did not exist in these associations. The leave-one-out test showed that these associations were stable.

Conclusion

We found that some MSDs were associated with the risk of dementia and provide evidence for the early detection of dementia in patients with MSDs and for the impact of inflammation on the central nervous system.

Impairment in cognitive function in patients with axial spondyloarthritis and psoriatic arthritis

Spondyloarthritis may contribute to deficits in cognition. The objective of this study was to compare cognitive abilities in patients with axial spondyloarthritis (axSpA) or psoriatic arthritis (PsA) with matched reference groups. This investigator-initiated, cross-sectional, exploratory study of adults with axSpA or PsA was conducted at two German rheumatology centres (November 2018-September 2019). All data on patient and disease characteristics and cognitive abilities were collected at a single visit. Cognitive function was assessed by the previously validated Memory and Attention Test subscores of selective attention, episodic working memory, and episodic short-term memory and compared with subscores from healthy age-, sex-, and education-matched reference subjects. The mean patient age was 51.1 and 55.8 years in the axSpA (n = 101) and PsA (n = 117) groups, respectively, and mean symptom duration was 13.7 and 10.3 years. Compared with matched reference subjects, axSpA and PsA patients showed significant impairments in selective attention (mean difference of -6.5 and -4.5, respectively, on a 45-point scale; P < 0.001 for both) and no significant differences in episodic working memory. The PsA cohort, but not the axSpA cohort, had significantly better episodic short-term memory subscores compared with matched reference subjects (mean change of 2.0 on a 15-point scale; P < 0.001). Explorative subgroup analyses were unable to identify factors influencing cognitive changes, including disease activity, pain, and function, but may have been underpowered. We conclude that impairments in selective attention may impact the ability of axSpA and PsA patients to process information. These findings warrant additional studies, including longitudinal analyses, in patients with spondyloarthritis.

Altered cerebral blood flow patterns in ankylosing spondylitis: A three-dimensional pseudo-continuous arterial spin labeling study

Objective

This study aimed to detect the cerebral blood flow (CBF) values changes in patients with ankylosing spondylitis (AS) and to evaluate the correlation between the CBF values and the specific clinical characteristics.

Materials and methods

Forty-eight patients with AS (43 male and 5 female) and 42 healthy controls (HCs) (38 male and 4 female) were recruited. Three-dimensional pseudo-continuous arterial spin labeling (3D-pCASL) was performed on a 3.0T magnetic resonance imaging (MRI). CBF values were obtained on the Philips post-processing workstation based on arterial spin labeling (ASL) data. The two-sample t-test was used to compare CBF differences. The correlation between CBF values and specific clinical characteristics of AS was evaluated.

Results

The AS group showed increased CBF values in the right precentral gyrus, the left inferior frontal gyrus, and the left temporal pole compared with HCs the AS group also showed decreased CBF values in the left precuneus and the left superior occipital gyrus compared with HCs. There were no significant correlations between the CBF values and the clinical characteristics including total back pain (TBP), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).

Conclusion

Patients with AS displayed CBF changes compared with HCs using 3D-PCASL. These results may enhance our understanding of the neural substrates of AS and provide evidence of AS-related neurological impairment.

Cognitive impairment in patients with psoriatic arthritis

BACKGROUND

Psoriatic arthritis (PsA) is an inflammatory rheumatic disorder associated with cutaneous psoriasis. Neurological manifestations are not uncommon in rheumatic diseases and recent studies point to a possible underestimation of cognitive impairment in this group of diseases. Our aim was to assess the cognitive impairment in patients with PsA.

METHODS

We carried out a cross-sectional case-control study with consecutive patients with PsA. Trained interviewers conducted structured and standardized in-person assessments. At baseline, functional limitations were characterized using the Health Assessment Questionnaire (HAQ). Cognitive function was evaluated with the Montreal Cognitive Assessment (MoCA) and neuropsychiatric symptoms were investigated with the Hospital Anxiety and Depression Scale (HADS). Using a proper statistical analysis, we compared the differences in the neurological outcomes between cases and controls.

RESULTS

A total of 37 patients with PsA and 36 healthy controls were included in our study. Patients with PsA had a worse MoCA score when compared to controls (p = 0.01). The proportion of patients with cognitive impairment according to MoCA between cases and controls was also statistically significant (91.9% vs 58.3%, p = 0.002). Executive skills, naming, language, and abstraction were the most affected domains. There was no statistical difference between the prevalence of neuropsychiatric symptoms between the two groups. Patients with increased functional limitations are associated with poor cognitive performance (p < 0.05).

CONCLUSION

Cognitive impairment might be a neurological manifestation of PsA.

Temperament and Character Profiles of Ankylosing Spondylitis Patients Compared With Major Depression Patients and Healthy Controls

BACKGROUND/OBJECTIVE

Depressive disorder is common in patients with ankylosing spondylitis (AS), who exhibit specific brain imaging abnormalities resembling those in major depression (MD). We compared temperament and character profiles between patients with AS and MD.

METHODS

The study involved 36 patients with AS, 40 with MD, and 36 healthy controls (HCs). The participants were age-, sex-, and education-matched. Depression, anxiety, temperament, and character were evaluated using the Temperament and Character Inventory and physician-rated Hamilton Depression and Anxiety Scales. Disease severity was assessed using the Bath Ankylosing Spondylitis Disease Activity, Radiology, Metrology, and Functionality Indexes; erythrocyte sedimentation rate; and C-reactive protein.

RESULTS

Depression and anxiety scores were highest in MD, lowest in HCs, and intermediate in AS (p < 0.001). Harm avoidance was significantly higher in MD and AS than HCs (p = 0.01). Reward dependency was lower (p = 0.011) and self-transcendence higher in AS only (p = 0.034). Bath Ankylosing Spondylitis Radiology Index was negatively correlated with depression (p = 0.020). Bath Ankylosing Spondylitis Radiology Index and Bath Ankylosing Spondylitis Metrology Index were negatively correlated with harm avoidance (p < 0.05). Disease duration was negatively correlated with self-transcendence (p = 0.027). Harm avoidance was correlated with depression score (p = 0.029). Patients under tumor necrosis factor α inhibitor treatment had lower cooperativeness score (p = 0.022).

CONCLUSIONS

Patients with AS had a specific Temperament and Character Inventory pattern. Harm avoidance was common in both AS and MD. In AS, harm avoidance and depression decreased in patients with progression, probably because progressive fusion of the spinal segments causes decrease in pain. Harm avoidance (fear of pain) seemed to be an acting factor for occurrence of depressive symptoms in AS.

Altered Functional Connectivity of the Primary Visual Cortex in Patients With Iridocyclitis and Assessment of Its Predictive Value Using Machine Learning

Purpose

To explore the intrinsic functional connectivity (FC) alteration of the primary visual cortex (V1) between individuals with iridocyclitis and healthy controls (HCs) by the resting-state functional magnetic resonance imaging (fMRI) technique, and to investigate whether FC findings be used to differentiate patients with iridocyclitis from HCs.

Methods

Twenty-six patients with iridocyclitis and twenty-eight well-matched HCs were recruited in our study and underwent resting-state fMRI examinations. The fMRI data were analyzed by Statistical Parametric Mapping (SPM12), Data Processing and Analysis for Brain Imaging (DPABI), and Resting State fMRI Data Analysis Toolkit (REST) software. Differences in FC signal values of the V1 between the individuals with iridocyclitis and HCs were compared using independent two-sample t-tests. Significant differences in FC between two groups were chosen as classification features for distinguishing individuals with iridocyclitis from HCs using a support vector machine (SVM) classifier that involved machine learning. Classifier performance was evaluated using permutation test analysis.

Results

Compared with HCs, patients with iridocyclitis displayed significantly increased FC between the left V1 and left cerebellum crus1, left cerebellum 10, bilateral inferior temporal gyrus, right hippocampus, and left superior occipital gyrus. Moreover, patients with iridocyclitis displayed significantly lower FC between the left V1 and both the bilateral calcarine and bilateral postcentral gyrus. Patients with iridocyclitis also exhibited significantly higher FC values between the right V1 and left cerebellum crus1, bilateral thalamus, and left middle temporal gyrus; while they displayed significantly lower FC between the right V1 and both the bilateral calcarine and bilateral postcentral gyrus (voxel-level P<0.01, Gaussian random field correction, cluster-level P<0.05). Our results showed that 63.46% of the participants were correctly classified using the leave-one-out cross-validation technique with an SVM classifier based on the FC of the left V1; and 67.31% of the participants were correctly classified based on the FC of the right V1 (P<0.001, non-parametric permutation test).

Conclusion

Patients with iridocyclitis displayed significantly disturbed FC between the V1 and various brain regions, including vision-related, somatosensory, and cognition-related regions. The FC variability could distinguish patients with iridocyclitis from HCs with substantial accuracy. These findings may aid in identifying the potential neurological mechanisms of impaired visual function in individuals with iridocyclitis.

Assessment of spontaneous brain activity patterns in patients with iridocyclitis: a resting-state study

Several studies demonstrated that patients with iridocyclitis were associated with vision loss and cognitive decline, whereas alterations in spontaneous brain activity occur in iridocyclitis patients remains unknown. The study aimed to explore spontaneous brain activity changes in iridocyclitis patients. Twenty-six patients with iridocyclitis and 26 healthy controls were finally included in our study. Resting-state MRI (rs-MRI) scan was conducted on both groups and the whole brain amplitude of low-frequency fluctuations (ALFFs) value was collected to assess differences in spontaneous brain activity. A receiver operating characteristic (ROC) curve was analyzed to distinguish between the fMRI data of patients with iridocyclitis and healthy controls. Patients with iridocyclitis showed significantly lower ALFF values in the right inferior parietal lobule, right calcarine, right superior temporal gyrus and right precentral gyrus compared to healthy controls and significantly higher ALFF values in the left superior frontal gyrus (P < 0.01, false discovery rate correction). The ROC curve analysis of different brain areas showed that the accuracies of ALFF value specificity between the iridocyclitis and healthy controls of the area under the curve were over 0.8. Our study highlighted an altered spontaneous activity in multiple brain regions, including the visual cortex, default-mode network, auditory area and sensorimotor areas in iridocyclitis. This may provide valuable information about underlying pathogenic mechanisms of iridocyclitis. These findings also indicate that rs-fMRI serves as a potential tool in the disease detection and evaluation of neurologic impairment in iridocyclitis.

Disrupted Neural Activity in Individuals With Iridocyclitis Using Regional Homogeneity: A Resting-State Functional Magnetic Resonance Imaging Study

Objective: This study used the regional homogeneity (ReHo) technique to explore whether spontaneous brain activity is altered in patients with iridocyclitis.

Methods: Twenty-six patients with iridocyclitis (14 men and 12 women) and 26 healthy volunteers (15 men and 11 women) matched for sex and age were enrolled in this study. The ReHo technique was used to comprehensively assess changes in whole-brain synchronous neuronal activity. The diagnostic ability of the ReHo method was evaluated by means of receive operating characteristic (ROC) curve analysis. Moreover, associations of average ReHo values in different brain areas and clinical characteristics were analyzed using correlation analysis.

Result: Compared with healthy volunteers, reduced ReHo values were observed in patients with iridocyclitis in the following brain regions: the right inferior occipital gyrus, bilateral calcarine, right middle temporal gyrus, right postcentral gyrus, left superior occipital gyrus, and left precuneus. In contrast, ReHo values were significantly enhanced in the right cerebellum, left putamen, left supplementary motor area, and left inferior frontal gyrus in patients with iridocyclitis, compared with healthy volunteers (false discovery rate correction, P < 0.05).

Conclusion: Patients with iridocyclitis exhibited disturbed synchronous neural activities in specific brain areas, including the visual, motor, and somatosensory regions, as well as the default mode network. These findings offer a novel image-guided research strategy that might aid in exploration of neuropathological or compensatory mechanisms in patients with iridocyclitis.

Increased Left Putamen Volume Correlates With Pain in Ankylosing Spondylitis Patients

Ankylosing spondylitis (AS) mainly affects the axial skeleton and is an important factor leading to chronic lower back pain in young individuals. However, few studies have explored alterations of brain gray matter volume in AS patients. The purpose of the present study was to describe brain gray matter abnormalities associated with AS pain. A total of 61 AS patients and 52 healthy controls (HCs) were included in this study. Using voxel-based morphometrics, we detected abnormal gray matter volume in AS patients. Based on the voxel-wise analysis, the gray matter volume in the left putamen of the AS group was increased significantly compared with that of the HC group. In addition, we found that the gray matter volume of the left putamen was positively correlated with the duration of AS and total back pain scores, whereas it was not significantly correlated with Bath Ankylosing Spondylitis Disease Activity Index scores, C-reactive protein, or erythrocyte sedimentation rate in AS patients. Taken together, our findings improve our understanding of the neural substrates of pain in AS and provide evidence of AS-related neurological impairment. Hence, further investigation of the pathophysiology of the left putamen in AS is warranted.

Is There a Brain/Heart Interaction in Rheumatoid Arthritis and Seronegative Spondyloartropathies? A Combined Brain/Heart Magnetic Resonance Imaging Reveals the Answer

PURPOSE OF REVIEW

To present the interaction between brain/heart and emphasize the role of combined brain/heart magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA) and other seronegative spondyloarthropathies (SNA).

RECENT FINDINGS

Both traditional cardiovascular disease (CVD) risk factors and intrinsic RA/SNA features contribute to the increased CVD-related morbidity/mortality. CVD in RA usually occurs a decade earlier than age- and sex-matched controls, and RA patients are twice more likely to develop myocardial infarction irrespective of age, history of prior CVD, and traditional CVD risk factors. RA also increases risk of non-ischemic heart failure (HF), valvular disease, and myo-pericarditis. CVD in SNA affects more commonly patients with long-standing disease. Ascending aortitis, aortic/mitral insufficiency, conduction defects, and diastolic dysfunction are the commonest findings in ankylosing spondylitis (AS). CVD is also the leading cause of death in psoriatic arthritis (PsA), due to myopericarditis, diastolic dysfunction, and valvular disease. Brain damage, due to either ischemic or hemorrhagic stroke and silent vascular damage, such as white matter hyperenhancement (WMH), is increased in both RA/SNA and may lead to cognitive dysfunction, depression, and brain atrophy. Magnetic resonance imaging (MRI) is ideal for serial brain/heart evaluation of patients with systemic diseases. RA/SNA patients are at high risk for brain/heart damage at early age, irrespectively of classic risk factors. Until more data will be obtained, a combined brain/heart MRI evaluation can be proposed in RA/SNA with new onset of arrhythmia and/or HF, cognitive dysfunction and/or depression.

Pain- and Fatigue-Related Functional and Structural Changes in Ankylosing Spondylitis: An fRMI Study

Background: Chronic pain and fatigue are two cardinal features of ankylosing spondylitis (AS) and how to effectively treat these conditions continues to be a challenge. The underlying mechanisms and the relationship between AS-related pain and fatigue remain poorly understood. The present study was conducted, therefore, to explore the brain functional and structural changes associated with pain and fatigue in AS.

Methods: A total of 65 AS patients (48 men and 17 women; 32.33 ± 8.6 years) and 53 age- and sex-matched controls were enrolled in the study. The patients underwent clinical assessment based on Total Back Pain scores, Fatigue Severity Scale, Bath Ankylosing Spondylitis Disease Activity Index, (BASDAI), high-sensitivity C-reactive Protein (hsCRP), erythrocyte sedimentation rate (ESR), and Beck Depression Inventory (BDI). Using 3T magnetic resonance imaging (3T-MRI), we analyzed the brain functional (connectivity and nodal properties) and structural (covariance and gray matter volumes) differences between AS patients and controls. Furthermore, we extracted the values of the significantly changed regions in the AS cohort and explored their association with pain and fatigue.

Results: In AS patients, there were functional and structural abnormalities distributed in the default mode network (DMN), salience network (SN), sensory/somatomotor network (SMN), dorsal attention network (DAN), task control network (TCN), and visual network, and some regions showed both types of changes. Among these, the functional connectivity (FC) between the left insula and medial prefrontal cortex, the betweenness centrality of the left medial prefrontal cortex and the gray matter volume of the right putamen tracked both pain and fatigue. In addition, pain was related to within-DMN FC disruption and nodal function / gray matter volumes changes in DMN, SN, and the visual network, while fatigue mainly involved the SMN, DAN, and TCN. Moreover, certain changes were also related to BASDAI and inflammation level.

Conclusion: This study offers new insights into understanding the neural mechanism of AS-related pain and fatigue, and could help to stratify patients based on the correlation features and ultimately move towards a personalized therapy.

Inflammation and the Central Nervous System in Inflammatory Rheumatic Disease

PURPOSE OF REVIEW

To review how peripheral inflammation in rheumatic disease influences the central nervous system. We consider recent studies of rheumatic disease that employ functional and structural neuroimaging in the context of inflammation, as well as recent studies considering how immunosuppressive therapy is associated with changes in brain function and structure.

RECENT FINDINGS

The most compelling evidence thus far comes from studies of rheumatoid arthritis and indicates that higher levels of inflammation are associated with changes in cognitive, affective, and pain-processing brain regions, some of which may be rectified by anti-inflammatory treatment. Comorbid symptoms such as widespread pain and fatigue may also be associated with these changes. Inflammation may be associated with compensatory activation of brain regions to offset structural changes. This emerging line of evidence suggests that communication between the brain and immune system are an important and underappreciated aspect of inflammatory rheumatic disease.

Biomechanical Factors in Psoriatic Disease: Defective Repair Exertion as a Potential Cause. Hypothesis Presentation and Literature Review

Joining main clinical manifestations of psoriatic skin disorder are inflammatory arthritis and nail lesions. Repetitive microdamage has been postulated as a main triggering factor in lesions of psoriatic arthritis. This concept of psoriatic disease might also be admissible for triggering nail lesions because the nail is a frequently traumatized structure. Here, we aimed to describe the conjectural injury mechanisms of nail complex with regard to acting biomechanical factors. Tissue repair response to physical microdamage may be altered in psoriatic disease. It is plausible to consider that a defective repair process in the dysregulated prepsoriatic tissue may lead to innate immune activation and further development of autoinflammatory lesions, although excessive inflammation is known to impair wound healing. Recently published data have revealed the importance of mechanosensitive Wingless-type (Wnt) signaling in the pathophysiology of psoriasis and ankylosing spondylitis. The Wnt signaling system is involved in morphogenesis, repair, and regeneration as a biologic process main regulator. Wnt5a seems to be a dominating mediator in both psoriatic plaques and during the spondylitis process that might also be a linking molecule of psoriatic response to mechanical stress. Future studies should focus on complex responsive interactions of tissue repair regulators regarded in psoriatic disease.

New concepts of pain

Active research is being conducted on musculoskeletal pain, and recent concepts will help clinicians and researchers to develop better approaches: -the new pain taxonomy recently has been modified with a third descriptor with the concept of nociplastic pain. -the latest International Classification of Diseases (ICD-11) includes an IASP task force that developed a new classification system for pain. In this new classification, one can differentiate primary musculoskeletal pain including fibromyalgia and low back pain and secondary musculoskeletal pain related to specific etiologies. -the concept of central sensitization in inflammatory rheumatic diseases is increasingly discussed. In these conditions, even with very active biological treatment, almost a third of patients are still complaining of persisting pain. These persisting pain states under adequate treatment, without any sign of inflammation, led researchers to look for evidence of central sensitization states.