Leptin promoter methylation in female patients with painful multisomatoform disorder and chronic widespread pain

Serum choline, leptin and interleukin-6 levels in fibromyalgia syndrome-induced pain: a case-control study

BACKGROUND

Fibromyalgia Syndrome (FMS) predominantly affects middle-aged women, characterized by musculoskeletal pain, fatigue, and cognitive issues. Choline, an endogenous molecule, may influence FMS due to its analgesic and anti-inflammatory properties. This study compared choline, leptin, and interleukin-6 (IL-6) levels in FMS patients and controls and examining their association with pain severity.

METHODS

Volunteers with FMS were clinically diagnosed at a Physical Medicine and Rehabilitation Department. The control group included pain-free volunteers. Pain severity was gauged using a numeric scale, dietary choline intake through a questionnaire. Serum choline, leptin and (interleukin)IL-6 levels were measured from fasting blood samples of volunteers with enzyme-linked immunosorbent assays (ELISA).

RESULTS

All FMS patients (n = 38) and healthy volunteers (n = 38) were female. Pain score in patients with FMS was 7.6 ± 0.2. Dietary choline intake was lower in patients with FMS than the controls (p = 0.036). Serum choline and leptin levels were lower in the FMS group compared to control (p = 0.03). Serum IL-6 levels were higher in the FMS group than in the control (p < 0.001). There was weak positive correlation between IL-6 levels and pain scores and there were no correlation between leptin levels and pain scores in FMS.

CONCLUSIONS

This research highlights FMS's complex nature, involving neurochemical, immunological, and nutritional factors. It suggests the significance of choline's anti-inflammatory effect, leptin's metabolic function, and IL-6's role in FMS pathology. The results suggest that reduced dietary choline might influence serum choline, leptin, and IL-6 levels, potentially impacting FMS-related pain. This points to the potential of supplementary choline intake in FMS management.

TRIAL REGISTRATION

Not applicable (Non-interventional study).

Divergent sex-specific pannexin-1 mechanisms in microglia and T cells underlie neuropathic pain

Chronic pain is a leading cause of disability, affecting more women than men. Different immune cells contribute to this sexual divergence, but the mechanisms, especially in females, are not well defined. We show that pannexin-1 (Panx1) channels on microglia and T cells differentially cause mechanical allodynia, a debilitating symptom of neuropathic pain. In male rodents, Panx1 drives vascular endothelial growth factor-A (VEGF-A) release from microglia. Cell-specific knockdown of microglial Panx1 or pharmacological blockade of the VEGF receptor attenuated allodynia in nerve-injured males. In females, nerve injury increased spinal CD8+ T cells and leptin levels. Leptin release from female-derived CD8+ T cells was Panx1 dependent, and intrathecal leptin-neutralizing antibody injection sex-specifically reversed allodynia. Adoptive transfer of female-derived CD8+ T cells caused robust allodynia, which was prevented by a leptin-neutralizing antibody or leptin small interfering RNA (siRNA) knockdown. Panx1-targeted approaches may alleviate neuropathic pain in both sexes, while T cell- and leptin-directed treatments could have sex-dependent benefits for women.

Epigenetic Landscapes of Pain: DNA Methylation Dynamics in Chronic Pain

Chronic pain is a prevalent condition with a multifaceted pathogenesis, where epigenetic modifications, particularly DNA methylation, might play an important role. This review delves into the intricate mechanisms by which DNA methylation and demethylation regulate genes associated with nociception and pain perception in nociceptive pathways. We explore the dynamic nature of these epigenetic processes, mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) enzymes, which modulate the expression of pro- and anti-nociceptive genes. Aberrant DNA methylation profiles have been observed in patients with various chronic pain syndromes, correlating with hypersensitivity to painful stimuli, neuronal hyperexcitability, and inflammatory responses. Genome-wide analyses shed light on differentially methylated regions and genes that could serve as potential biomarkers for chronic pain in the epigenetic landscape. The transition from acute to chronic pain is marked by rapid DNA methylation reprogramming, suggesting its potential role in pain chronicity. This review highlights the importance of understanding the temporal dynamics of DNA methylation during this transition to develop targeted therapeutic interventions. Reversing pathological DNA methylation patterns through epigenetic therapies emerges as a promising strategy for pain management.

Identification and validation of aging-related genes in neuropathic pain using bioinformatics

Background

Neuropathic pain (NP) is a debilitating and refractory chronic pain with a higher prevalence especially in elderly patients. Cell senescence considered a key pathogenic factor in NP. The objective of this research is to discover genes associated with aging in peripheral blood of individuals with NP using bioinformatics techniques.

Methods

Two cohorts (GSE124272 and GSE150408) containing peripheral blood samples of NP were downloaded from the GEO database. By merging the two cohorts, differentially expressed aging-related genes (DE-ARGs) were obtained by intersection with aging-related genes. The potential biological mechanisms of DE-ARGs were further analyzed through GO and KEGG. Three machine learning methods, namely, LASSO, SVM-RFE, and Random Forest, were utilized to identify diagnostic biomarkers. A Nomogram model was developed to assess their diagnostic accuracy. The validation of biomarker expression and diagnostic effectiveness was conducted in three distinct pain cohorts. The CIBERSORT algorithm was employed to evaluate the immune cell composition in the peripheral blood of patients with NP and investigate its association with the expression of diagnostic biomarkers.

Results

This study identified a total of 24 DE-ARGs, mainly enriched in "Chemokine signaling pathway," "Inflammatory mediator regulation of TRP channels," "HIF-1 signaling pathway" and "FOXO signaling pathway". Three machine learning algorithms identified a total of four diagnostic biomarkers (CEBPA, CEACAM1, BTG3 and IL-1R1) with good diagnostic performance and the similar expression difference trend in different types of pain cohorts. The expression levels of CEACAM1 and IL-1R1 exhibit a positive correlation with the percentage of neutrophils.

Conclusion

Using machine learning techniques, our research identified four diagnostic biomarkers related to aging in peripheral blood, providing innovative approaches for the diagnosis and treatment of NP.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

DNA Methylation Changes in Blood Cells of Fibromyalgia and Chronic Fatigue Syndrome Patients

Purpose

Fibromyalgia (FM) and Chronic Fatigue Syndrome (CFS) affect 0.4% and 1% of society, respectively, and the prevalence of these pain syndromes is increasing. To date, no strong association between these syndromes and the genetic background of affected individuals has been shown. Therefore, it is plausible that epigenetic changes might play a role in the development of these syndromes.

Patients and Methods

Three previous studies have attempted to elaborate the involvement of genome-wide methylation changes in blood cells in the development of fibromyalgia and chronic fatigue syndrome. These studies included 22 patients with fibromyalgia and 127 patients with CFS, and the results of the studies were largely discrepant. Contradicting results of those studies may be attributed to differences in the omics data analysis approaches used in each study. We reanalyzed the data collected in these studies using an updated and coherent data-analysis framework.

Results

Overall, the methylation changes that we observed overlapped with previous results only to some extent. However, the gene set enrichment analyses based on genes annotated to methylation changes identified in each of the analyzed datasets were surprisingly coherent and uniformly associated with the physiological processes that, when affected, may result in symptoms characteristic of fibromyalgia and chronic fatigue syndrome.

Conclusion

Methylomes of the blood cells of patients with FM and CFS in three independent studies have shown methylation changes that appear to be implicated in the pathogenesis of these syndromes.

Associations between chronic widespread pain, pressure pain thresholds, leptin, and metabolic factors in individuals with knee pain

OBJECTIVE

The aim was to study associations between chronic widespread pain, widespread pain sensitivity, leptin, and metabolic factors in individuals with knee pain. A secondary aim was to study these associations in a subgroup of individuals with normal BMI.

METHOD

This cross-sectional study included 265 individuals. The participants were categorised into three different pain groups: Chronic widespread pain (CWP), chronic regional pain (ChRP), or no chronic pain (NCP). The pressure pain thresholds (PPTs) were assessed using computerised pressure algometry. Low PPTs were defined as having PPTs in the lowest third of all tender points. Leptin and metabolic factors such as BMI, visceral fat area (VFA), lipids, and glucose were also assessed.

RESULT

Sixteen per cent reported CWP, 15% had low PPTs, and 4% fulfilled both criteria. Those who fulfilled the criteria for CWP were more often women, more obese, and had increased leptin levels. In logistic regression, adjusted for age and gender, leptin was associated with fulfilling criteria for CWP, OR 1.015 (95% CI 1.004-1.027, p = 0.008). In logistic regression, adjusted for age and gender, leptin was associated with low PPTs, OR 1.016 (95% CI 1.004-1.029, p = 0.012). Leptin was also associated with fulfilling both criteria, adjusted for age, sex, and visceral fat area (VFA), OR 1.030 (95% CI 1.001-1.060), p = 0.040.

CONCLUSION

Leptin was associated with fulfilling the combined criteria for chronic widespread pain and low PPTs, even after adjusting for the visceral fat area (VFA). Longitudinal studies are needed to study the causal relationships between leptin and the development of widespread pain.

TRIAL REGISTRATION

clinicalTrials.gov Identifier: NCT04928170.

A Comprehensive Review of the Genetic and Epigenetic Contributions to the Development of Fibromyalgia

This narrative review summarizes the current knowledge of the genetic and epigenetic contributions to the development of fibromyalgia (FM). Although there is no single gene that results in the development of FM, this study reveals that certain polymorphisms in genes involved in the catecholaminergic pathway, the serotonergic pathway, pain processing, oxidative stress, and inflammation may influence susceptibility to FM and the severity of its symptoms. Furthermore, epigenetic changes at the DNA level may lead to the development of FM. Likewise, microRNAs may impact the expression of certain proteins that lead to the worsening of FM-associated symptoms.

Neuroendocrine and neuroimmune mechanisms underlying comorbidity of pain and obesity

Pain and obesity, as well as their associated impairments, are major health concerns. Understanding the relationship between the two is the focus of a growing body of research. However, early researches attribute increased mechanical stress from excessive weight as the main factor of obesity-related pain, which not only over-simplify the association, but also fail to explain some controversial outcomes arising from clinical investigations. This review focuses on neuroendocrine and neuroimmune modulators importantly involved in both pain and obesity, analyzing nociceptive and anti-nociceptive mechanisms based on neuroendocrine pathways including galanin, ghrelin, leptin and their interactions with other neuropeptides and hormone systems which have been reported to play roles in pain and obesity. Mechanisms of immune activities and metabolic alterations are also discussed, due to their intense interactions with neuroendocrine system and crucial roles in the development and maintenance of inflammatory and neuropathic pain. These findings have implications for health given rising rates of obesity and pain-related diagnoses, by providing novel weight-control and analgesic therapies targeted on specific pathways.

The interplay of chronic stress and genetic traits discriminates between patients suffering from multisomatoform disorder with pain as the leading symptom and matched controls

OBJECTIVE

Somatoform disorders and functional somatic syndromes (FSS) with symptoms that are not sufficiently explained by physical or technical examination are among the most challenging underlying causes. Many different somatoform disorders and FSS have overlapping symptoms, often with pain as the most prevalent one, leading to a high burden of disease. The concept of multisomatoform disorder (MSD) has been developed to acknowledge that fact. We analyzed a group of 151 patients and 149 matched controls to identify interactions of genetic and environmental factors with a possible influence on the development of MSD.

DESIGN

In a retrospective case-control study, we performed a statistical analysis on 151 patients and 149 matched controls using logistic regression and a Classification and Regression Tree (CART) analysis.

RESULTS

The logistic regression analysis of genes and environmental factors demonstrated significant differences in the results of the Trier Inventory of Chronic Stress (TICS) questionnaire, the single nucleotide polymorphism rs1800955 of the dopamine receptor D4 and the single nucleotide polymorphism rs4818 of the enzyme catechol-O-methyltransferase between patients with MSD and healthy controls. The resulting decision tree of the CART analysis determined that the TICS questionnaire was able to differentiate patients and controls most accurately, followed by certain genotypes of the 5-hydroxytryptamine receptor 2A and a single nucleotide polymorphism of the enzyme catechol-O-methyltransferase.

CONCLUSIONS

The results of the statistical analysis identified a gene-environmental interaction possibly leading to MSD. The resulting identifiers could be used as a reference to inform diagnostic algorithms to easier identify patients suffering from MSD.