Changes in brain white matter structure are associated with urine proteins in urologic chronic pelvic pain syndrome (UCPPS): A MAPP Network study

What has brain diffusion magnetic resonance imaging taught us about chronic primary pain: a narrative review

ABSTRACT

Chronic pain is a pervasive and debilitating condition with increasing implications for public health, affecting millions of individuals worldwide. Despite its high prevalence, the underlying neural mechanisms and pathophysiology remain only partly understood. Since its introduction 35 years ago, brain diffusion magnetic resonance imaging (MRI) has emerged as a powerful tool to investigate changes in white matter microstructure and connectivity associated with chronic pain. This review synthesizes findings from 58 articles that constitute the current research landscape, covering methods and key discoveries. We discuss the evidence supporting the role of altered white matter microstructure and connectivity in chronic primary pain conditions, highlighting the importance of studying multiple chronic pain syndromes to identify common neurobiological pathways. We also explore the prospective clinical utility of diffusion MRI, such as its role in identifying diagnostic, prognostic, and therapeutic biomarkers. Furthermore, we address shortcomings and challenges associated with brain diffusion MRI in chronic primary pain studies, emphasizing the need for the harmonization of data acquisition and analysis methods. We conclude by highlighting emerging approaches and prospective avenues in the field that may provide new insights into the pathophysiology of chronic pain and potential new therapeutic targets. Because of the limited current body of research and unidentified targeted therapeutic strategies, we are forced to conclude that further research is required. However, we believe that brain diffusion MRI presents a promising opportunity for enhancing our understanding of chronic pain and improving clinical outcomes.

This pain drives me crazy: Psychiatric symptoms in women with interstitial cystitis/bladder pain syndrome

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is an at least 6-mo noninfectious bladder inflammation of unknown origin characterized by chronic suprapubic, abdominal, and/or pelvic pain. Although the term cystitis suggests an inflammatory or infectious origin, no definite cause has been identified. It occurs in both sexes, but women are twice as much affected.

AIM

To systematically review evidence of psychiatric/psychological changes in persons with IC/BPS.

METHODS

Hypothesizing that particular psychological characteristics could underpin IC/BPS, we investigated in three databases the presence of psychiatric symptoms and/or disorders and/or psychological characteristics in patients with IC/BPS using the following strategy: ("interstitial cystitis" OR "bladder pain syndrome") AND ("mood disorder" OR depressive OR antidepressant OR depression OR depressed OR hyperthymic OR mania OR manic OR rapid cyclasterisk OR dysthymiasterisk OR dysphoriasterisk).

RESULTS

On September 27, 2023, the PubMed search produced 223 articles, CINAHL 62, and the combined PsycLIT/ PsycARTICLES/PsycINFO/Psychology and Behavioral Sciences Collection search 36. Search on ClinicalTrials.gov produced 14 studies, of which none had available data. Eligible were peer-reviewed articles reporting psychiatric/psychological symptoms in patients with IC/BPS, i.e. 63 articles spanning from 2000 to October 2023. These studies identified depression and anxiety problems in the IC/BPS population, along with sleep problems and the tendency to catastrophizing.

CONCLUSION

Psychotherapies targeting catastrophizing and life stress emotional awareness and expression reduced perceived pain in women with IC/BPS. Such concepts should be considered when implementing treatments aimed at reducing IC/BPS-related pain.

Implicit Motor Imagery for Chronic Pelvic Pain: A Cross-Sectional Case-Control Study

Implicit motor imagery (IMI), with an image laterality discrimination (LD) task, has been proposed as a useful therapeutic tool to restore body schema in patients with chronic pelvic pain (CPP). The aim of this study was to analyse the existence of differences between patients with CPP and healthy individuals in order to justify the use of IMI. An observational, cross-sectional study with non-probabilistic sampling was designed as a one-to-one matched case-control study. Through a web link designed for this purpose, a total of 40 abdominoperineal images were shown to 130 participants during the laterality task. Outcome measures were pain intensity (visual analogue scale, VAS), accuracy, response time (RT), and CPPQ-Mohedo score (Chronic Pelvic Pain Questionnaire-Mohedo). This was an observational, cross-sectional study with a total of 64 CPP patients and 66 healthy individuals. The comparative analysis between groups revealed significant differences in accuracy, CPPQ-Mohedo and VAS (p < 0.001), but not in RT; in patients with CPP, accuracy was correlated with a lower CPPQ-Mohedo score and RT and, the greater the pain intensity, the higher the CPPQ-Mohedo score and RT, and the lower the accuracy. In the LD task, the patients with CPP made more mistakes than the healthy individuals. IMI could be a useful and complementary tool in the therapeutic approach for patients with CPP.

How Well Do Current Laboratory Biomarkers Inform Clinical Decision-Making in Chronic Pain Management?

OBJECTIVE

Decision-making in chronic pain patients involves a combination of subjective and objective criteria, including patient history, physical examination, imaging, and patient response to prior treatments, clinical experience, probabilities, and recognition of patterns. However, there is a distinct lack of objective laboratory biomarkers in use in routine clinical care. The objective was to review the literature to identify and describe specific biomarkers in chronic pain management.

METHODS

This is a narrative review of the literature regarding the use of laboratory biomarkers in chronic pain. A librarian-assisted literature search of the PubMed, Science Direct, and Google Scholar databases was performed and resulted in 304 possible manuscripts. We included manuscripts assessing laboratory collected biomarkers from urine, serum, cerebrospinal fluid, and saliva. After screening and review of the initial literature search results, a total of 75 manuscripts were included in the narrative review.

CONCLUSION

The studies reviewed suggested that specific biomarkers may help identify those patients at risk of disease development and function as a prognostic indicator for disease progression and treatment response. However, additional research is necessary before specific recommendations can be made, and current clinical decision-making is modified.

Preliminary Analysis of Brain Footprints in Multiple Sclerosis Females with Detrusor Sphincter Dyssynergia: A Concurrent Urodynamic and Functional Magnetic Resonance Imaging Study

Purpose

This study evaluates the grey and white brain matter characteristics in women with multiple sclerosis (MS) and detrusor sphincter dyssynergia (DSD). Grey matter is assessed via the functional connectivity (FC) of brain regions activated during voiding, using functional magnetic resonance imaging (fMRI). Two white matter tracts involved in bladder function, the anterior thalamic radiation (ATR) and superior longitudinal fasciculus (SLF), were evaluated using diffusion tensor imaging (DTI).

Methods

Twenty-seven women with MS (two groups: no-DSD (n=23) or DSD (n=4)), and eight healthy controls (HC) underwent concurrent urodynamic-fMRI evaluation with four cycles of bladder filling and emptying. A FC similarity measure (FC_sim) was calculated for each subject to express the similarity of individual FC at voiding initiation compared to all FC patterns. ATR and SLF tracts were traced and their fractional anisotropy (FA) and mean diffusivity (MD) were recorded.

Results

Mean FC_sim values were significantly different among the three groups indicating distinct FC patterns; however, no significant difference was found between DSD and no-DSD groups. DSD group showed trends of lower FA and higher MD - indicating loss of coherence - in all tracts compared to HCs, and in the left and right ATR when compared to MS women with neither DSD nor voiding dysfunction (VD), suggesting more damage in these tracts for MS women with DSD.

Conclusions

Women with MS show distinctly different FC patterns compared to HCs. There are trends showing more damage in the ATR in women with MS and DSD compared to those with neither DSD nor VD.

Cognitive behavioral therapy for irritable bowel syndrome induces bidirectional alterations in the brain-gut-microbiome axis associated with gastrointestinal symptom improvement

BACKGROUND

There is growing recognition that bidirectional signaling between the digestive tract and the brain contributes to irritable bowel syndrome (IBS). We recently showed in a large randomized controlled trial that cognitive behavioral therapy (CBT) reduces IBS symptom severity. This study investigated whether baseline brain and gut microbiome parameters predict CBT response and whether response is associated with changes in the brain-gut-microbiome (BGM) axis.

METHODS

Eighty-four Rome III-diagnosed IBS patients receiving CBT were drawn from the Irritable Bowel Syndrome Outcome Study (IBSOS; ClinicalTrials.gov NCT00738920) for multimodal brain imaging and psychological assessments at baseline and after study completion. Fecal samples were collected at baseline and post-treatment from 34 CBT recipients for 16S rRNA gene sequencing, untargeted metabolomics, and measurement of short-chain fatty acids. Clinical measures, brain functional connectivity and microstructure, and microbiome features associated with CBT response were identified by multivariate linear and negative binomial models.

RESULTS

At baseline, CBT responders had increased fecal serotonin levels, and increased Clostridiales and decreased Bacteroides compared to non-responders. A random forests classifier containing 11 microbial genera predicted CBT response with high accuracy (AUROC 0.96). Following treatment, CBT responders demonstrated reduced functional connectivity in regions of the sensorimotor, brainstem, salience, and default mode networks and changes in white matter in the basal ganglia and other structures. Brain changes correlated with microbiome shifts including Bacteroides expansion in responders.

CONCLUSIONS

Pre-treatment intestinal microbiota and serotonin levels were associated with CBT response, suggesting that peripheral signals from the microbiota can modulate central processes affected by CBT that generate abdominal symptoms in IBS. CBT response is characterized by co-correlated shifts in brain networks and gut microbiome that may reflect top-down effects of the brain on the microbiome during CBT. Video abstract.

Relationship of Bladder Pain With Clinical and Urinary Markers of Neuroinflammation in Women With Urinary Urgency Without Urinary Incontinence

PURPOSE

The pathogenesis of bladder pain is poorly understood. Our hypothesis is that in women with urinary urgency without incontinence, bladder pain is associated with the presence of neurogenic inflammation in the bladder wall and neuroinflammatory biomarkers in the urine.

METHODS

We conducted a prospective cross-sectional study of women with urinary urgency without incontinence. Urinary symptoms were measured using Female Genitourinary Pain Index. Neuropathic pain, a clinical biomarker of neuroinflammation, was measured using the PainDETECT questionnaire. Inflammatory neuropeptides measured in the urine included nerve growth factor (NGF), brain-derived neurotrophic factor, vascular endothelial growth factor, and osteopontin. Neuropathic pain scores and urinary neuropeptide levels were compared between patients with and without bladder pain using univariable and multivariable analyses.

RESULTS

In 101 women with urinary urgency without incontinence, 62 (61%) were in the bladder pain group (visual analog scale score, ≤ 3), whereas 39 (39%) were in the no bladder pain group. Urinary symptom scores (5.0 ± 3.1 versus 3.5 ± 2.4, P < 0.001) and neuropathic pain scores (13.3 ± 8.6 vs 5.1 ± 4.8, P < 0.001) were significantly higher for the bladder pain group than for the no bladder pain group. On multivariable analysis after controlling for age, body mass index, and severity of urinary urgency, bladder pain score was significantly associated with elevated urinary levels of vascular endothelial growth factor (P = 0.04) and osteopontin (P = 0.02), whereas the neuropathic pain score was significantly associated with an increased NGF level (P = 0.03).

CONCLUSIONS

In women with urinary urgency without incontinence, bladder pain is associated with the presence of clinical and urinary biomarkers of neuroinflammation.

Are White Matter Tract Integrities Different in Multiple Sclerosis Women With Voiding Dysfunction?

OBJECTIVES

Two white matter tracts (WMTs) are proposed to be involved in bladder function: anterior thalamic radiation and superior longitudinal fasciculus. Multiple sclerosis (MS) patients with voiding dysfunction (VD) may have distinct changes in these 2 WMTs. This study aims to compare the fractional anisotropy (FA) and mean diffusivity (MD) from diffusion tensor imaging of MS females with and without VD versus healthy controls (HCs).

METHODS

Prospective observational cohorts of 28 female MS patients and 11 HCs were recruited. Multiple sclerosis patients were divided into 2 groups: voiders (patients without VD, n = 14) and VD (patients with VD, n = 14). Diffusion tensor imaging of each subject was obtained, from which FA and MD maps were generated. The mean FA and MD of each WMT on both sides were analyzed using one-way analysis of variance and pairwise comparison with adjusted P values.

RESULTS

Overall MS patients had significantly lower mean FA (loss of coherence) and significantly higher mean MD (increased free diffusion) than HCs in both WMTs, indicating more damage. Furthermore, VD showed a trend of loss of integrity in both WMTs when compared with voiders with lower FA and higher MD.

CONCLUSIONS

There is damage reflected by lower FA and higher MD values in the proposed WMTs involved in bladder function in MS women. Voiding dysfunction in this patient population can be attributed to these damages considering women with VD demonstrated a trend of deterioration in these WMTs compared with women without VD. Future studies with larger sample sizes should be done to further confirm this correlation.

Association of Longitudinal Changes in Symptoms and Urinary Biomarkers in Patients with Urological Chronic Pelvic Pain Syndrome: A MAPP Research Network Study

PURPOSE

We analyzed a series of novel noninvasive urinary biomarkers for their ability to objectively monitor the longitudinal clinical status of patients with urological chronic pelvic pain syndrome.

MATERIALS AND METHODS

Baseline, 6 and 12-month urine samples were collected (216) and used to quantify vascular endothelial growth factor, vascular endothelial growth factor (VEGF) receptor 1 (R1), neutrophil gelatinase associated lipocalin (NGAL), matrix metalloproteinase-2, matrix metalloproteinase (MMP)-9, and MMP-9/NGAL complex by enzyme-linked immunosorbent assays. Patient symptom changes were classified as improved, stable or worse using a functional clustering algorithm. Proportional odds models were used to evaluate the association between symptom change and urinary biomarkers.

RESULTS

Across all sampled participants, longitudinal decreases in normalized VEGF concentration (pg/μg) were associated with pain severity improvement, and decreases in MMP-9, NGAL and VEGF-R1 concentration (pg/ml) as well as NGAL normalized concentration were associated with improved urinary symptoms. Longitudinal decreases in normalized VEGF-R1 were associated with pain improvement in patients with moderate widespreadness, no bladder symptoms and no painful filling. Lower baseline normalized VEGF-R1 concentration was associated with pain improvement in patients with pelvic pain only. Higher baseline MMP-9/NGAL levels were associated with pain and urinary improvement across all participants. Moreover, longitudinal increases in MMP-2 concentration was associated with improved pain in men and patients with painful filling.

CONCLUSIONS

Our results suggest these urinary biomarkers may be useful in monitoring urological chronic pelvic pain syndrome symptom changes with respect to both urinary severity and pain severity. With further testing, they may represent objective biological measures of urological chronic pelvic pain syndrome progression and/or resolution while also providing insight into the pathophysiology of urological chronic pelvic pain syndrome.