Differences between serum polar lipid profiles of male and female rheumatoid arthritis patients in response to glucocorticoid treatment

High-throughput metabolomics exploring the pharmacological effects and mechanism of icariin on rheumatoid arthritis rat based on ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Introduction

Metabolomics could provide insights into the pharmacological effects and action mechanisms of drugs through assessment of the changes in relevant biomarkers and biological pathways. Icariin (ICA) is a promising ffavonoid compound known to have significant anticancer activity; however, the pharmacological mechanisms of ICA in the treatment of rheumatoid arthritis (RA) need to be explored further.

Methods

The changes in the metabolic profiles of serum samples were revealed using non-targeted metabolomics based on ultrahigh-performance liquid chromatography coupled with quadrupole time-of-fight mass spectrometry. Tissue histopathology, physical parameters, and biochemical indicators were also measured and analyzed to reveal the mechanisms of ICA in the treatment of RA.

Results and discussion

Thirty-one potential biomarkers were identified to highlight the metabolic disorders in an RA animal model, out of which twenty-three were regulated by ICA treatment. These biomarkers were mainly involved in alanine, aspartate, and glutamate metabolism; arachidonic acid metabolism; citrate cycle; pyruvate metabolism; and glycolysis/gluconeogenesis pathways. The anticancer mechanism of ICA on RA may be attributed to amelioration of the amino acid metabolism, unsaturated fatty acid metabolism, citrate cycle, pyruvate metabolism, and others, which in turn regulate the oxidative stress state and inflammatory effects. Thus, metabolomics is a promising approach for revealing the biomarker distribution and pathways of RA to determine the effects and mechanisms of ICA, which can benefit the development of natural medicines.

Sex difference in human diseases: mechanistic insights and clinical implications

Sex characteristics exhibit significant disparities in various human diseases, including prevalent cardiovascular diseases, cancers, metabolic disorders, autoimmune diseases, and neurodegenerative diseases. Risk profiles and pathological manifestations of these diseases exhibit notable variations between sexes. The underlying reasons for these sex disparities encompass multifactorial elements, such as physiology, genetics, and environment. Recent studies have shown that human body systems demonstrate sex-specific gene expression during critical developmental stages and gene editing processes. These genes, differentially expressed based on different sex, may be regulated by androgen or estrogen-responsive elements, thereby influencing the incidence and presentation of cardiovascular, oncological, metabolic, immune, and neurological diseases across sexes. However, despite the existence of sex differences in patients with human diseases, treatment guidelines predominantly rely on male data due to the underrepresentation of women in clinical trials. At present, there exists a substantial knowledge gap concerning sex-specific mechanisms and clinical treatments for diverse diseases. Therefore, this review aims to elucidate the advances of sex differences on human diseases by examining epidemiological factors, pathogenesis, and innovative progress of clinical treatments in accordance with the distinctive risk characteristics of each disease and provide a new theoretical and practical basis for further optimizing individualized treatment and improving patient prognosis.

Relationship Between the Lipidome Profile and Disease Activity in Patients with Rheumatoid Arthritis

Lipid mediators have been suggested to play important roles in the pathogenesis of rheumatoid arthritis (RA). Lipidomics has recently allowed for the comprehensive analysis of lipids and has revealed the potential of lipids as biomarkers for the early diagnosis of RA and prediction of therapeutic responses. However, the relationship between disease activity and the lipid profile in RA remains unclear. In the present study, we performed a plasma lipidomic analysis of 278 patients with RA during treatment and examined relationships with disease activity using the Disease Activity Score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR). In all patients, five lipids positively correlated and seven lipids negatively correlated with DAS28-ESR. Stearic acid [FA(18:0)] (r = -0.45) and palmitic acid [FA(16:0)] (r = -0.38) showed strong negative correlations. After adjustments for age, body mass index (BMI), and medications, stearic acid, palmitic acid, bilirubin, and lysophosphatidylcholines negatively correlated with disease activity. Stearic acid inhibited osteoclast differentiation from peripheral blood monocytes in in vitro experiments, suggesting its contribution to RA disease activity by affecting bone metabolism. These results indicate that the lipid profile correlates with the disease activity of RA and also that some lipids may be involved in the pathogenesis of RA.

Polymyalgia rheumatica shows metabolomic alterations that are further altered by glucocorticoid treatment: Identification of metabolic correlates of fatigue

OBJECTIVE

In polymyalgia rheumatica (PMR), glucocorticoids (GCs) relieve pain and stiffness, but fatigue may persist. We aimed to explore the effect of disease, GCs and PMR symptoms in the metabolite signatures of peripheral blood from patients with PMR or the related disease, giant cell arteritis (GCA).

METHODS

Nuclear magnetic resonance spectroscopy was performed on serum from 40 patients with untreated PMR, 84 with new-onset confirmed GCA, and 53 with suspected GCA who later were clinically confirmed non-GCA, and 39 age-matched controls. Further samples from PMR patients were taken one and six months into glucocorticoid therapy to explore relationship of metabolites to persistent fatigue. 100 metabolites were identified using Chenomx and statistical analysis performed in SIMCA-P to examine the relationship between metabolic profiles and, disease, GC treatment or symptoms.

RESULTS

The metabolite signature of patients with PMR and GCA differed from that of age-matched non-inflammatory controls (R2 > 0.7). There was a smaller separation between patients with clinically confirmed GCA and those with suspected GCA who later were clinically confirmed non-GCA (R2 = 0.135). In PMR, metabolite signatures were further altered with glucocorticoid treatment (R2 = 0.42) but did not return to that seen in controls. Metabolites correlated with CRP, pain, stiffness, and fatigue (R2 ≥ 0.39). CRP, pain, and stiffness declined with treatment and were associated with 3-hydroxybutyrate and acetoacetate, but fatigue did not. Metabolites differentiated patients with high and low fatigue both before and after treatment (R2 > 0.9). Low serum glutamine was predictive of high fatigue at both time points (0.79-fold change).

CONCLUSION

PMR and GCA alter the metabolite signature. In PMR, this is further altered by glucocorticoid therapy. Treatment-induced metabolite changes were linked to measures of inflammation (CRP, pain and stiffness), but not to fatigue. Furthermore, metabolite signatures distinguished patients with high or low fatigue.

Are comorbidities of patients with adrenal incidentaloma tied to sex?

Background

A recent cross-sectional study showed that both comorbidities and mortality in patients with adrenal incidentaloma (AI) are tied to sex. However, few longitudinal studies evaluated the development of arterial hypertension, hyperglycemia, dyslipidemia and bone impairment in patients with AI. The aim of this study is to analyze the impact of sex in the development of these comorbidities during long-term follow-up.

Methods

We retrospectively evaluated 189 patients (120 females, 69 males) with AI, from four referral centers in Italy and Croatia. Clinical characteristics, comorbidities and cortisol after 1-mg dexamethasone suppression test (1-mg DST) were assessed at baseline and at last follow-up visit (LFUV). Median follow-up was 52 (Interquartile Range 25-86) months.

Results

The rates of arterial hypertension and hyperglycemia increased over time both in females (65.8% at baseline versus 77.8% at LFUV, p=0.002; 23.7% at baseline versus 39.6% at LFUV, p<0.001; respectively) and males (58.0% at baseline versus 69.1% at LFUV, p=0.035; 33.8% at baseline versus 54.0% at LFUV, p<0.001; respectively). Patients were stratified in two groups using 1.8 µg/dl as cut-off of cortisol following 1-mg DST: non-functional adrenal tumors (NFAT) and tumors with mild autonomous cortisol secretion (MACS). In the NFAT group (99 patients, females 62.6%), at baseline, we did not observe any difference in clinical characteristics and comorbidities between males and females. At LFUV, males showed a higher frequency of hyperglycemia than females (57.6% versus 33.9%, p=0.03). In the MACS group (89 patients, females 64.0%), at baseline, the prevalence of hypertension, hyperglycemia and dyslipidemia was similar between sexes, despite females were younger (60, IQR 55-69 versus 67.5, IQR 61-73, years; p=0.01). Moreover, females presented higher rates of bone impairment (89.3% versus 54.5%, p=0.02) than males. At LFUV, a similar sex-related pattern was observed.

Conclusion

Patients with AI frequently develop arterial hypertension and hyperglycemia and should be periodically checked for these comorbidities, regardless of sex. In patients with MACS, the lack of difference between sexes in the frequency of cardiometabolic comorbidities despite that females are younger, and the higher frequency of bone impairment in females, suggest a sex-specific effect of cortisol.

Sexual dimorphism in the gut microbiota and sexual dimorphism in chronic diseases: Association or causation?

Understanding the sexual dimorphism in diseases is essential to investigate the pathogenesis of some chronic diseases (e.g., autoimmune diseases, etc). The gut microbiota has been found to show a notable impact on the pathology of several chronic diseases in recent years. Intriguingly, the composition of the gut microbiota varies between sexes. Here, we reviewed 'facts and fiction' regarding sexual dimorphism in chronic diseases and sexual dimorphism in the gut microbiota respectively. The association and causative relationship between them aiming to elucidate the pathological mechanisms of sexual dimorphism in chronic diseases were further explored. The development of gender-special food products based on the sexual dimorphism in the gut microbiota were recommended, which would be beneficial to facilitating the personalized treatment.

Single-cell RNA transcriptomic and plasma Lipidomic reveal the potential mechanisms of a Methotrexate-based therapy against Rheumatoid Arthritis

OBJECTIVE

To assess whether a Methotrexate-based therapy could achieve more clinical benefit, we arranged a Simon 2-Stage Phase 1 Trial. Single-cell RNA sequencing and lipidomic profiling were performed to reveal the potential mechanisms.

METHODS

Patients were enrolled in an open-label, Simon 2-stage, single-center, single-arm trial at Guangdong Provincial Hospital of Chinese Medicine. Main inclusion criteria were defined as follows: Aged 18 to 70, low to medium disease activity, fulfilled the RA classification criteria of EULAR/ACR 2010. Patients received the oral medication of MTX 10-15 mg weekly and natural product granules twice a day. Primary outcome was the American College of Rheumatology (ACR) 20% preliminary definition of improvement. Single-cell RNA sequencing(scRNA-seq) on peripheral blood mononuclear cells (PBMCs) was used to show the aberrant metabolism before and after the trial. Plasma lipidomic profiling quantified the lipid changes caused by this MTX-based therapy. Finally, post-hoc analysis on responders and non-responders were used for further analysis.

RESULTS

Between October 2020 and June 2022, 46 patients received treatment, while 42 finished follow-ups. 27 of 46 (58.70%) patients achieved ACR20, and significant changes were observed in several secondary outcomes. Comparative scRNA-seq analysis before and after the treatment revealed that lipidomic metabolism was broadly downregulated. Plasma lipidomic profiling reveals that 40 lipids were observed significantly changed. Post-hoc analysis showed the lipid changes were separately linked to clinical parameters in responders and non-responders.

CONCLUSION

The study reveals that the combination therapy of HQT+MTX is effective and has a certain correlation with lipid metabolism, but more rigorous study design is still needed to confirm this speculation.

Metabolomics in rheumatoid arthritis: Advances and review

Rheumatoid arthritis (RA) is an autoimmune disease accompanied by metabolic alterations. The metabolic profiles of patients with RA can be determined using targeted and non-targeted metabolomics technology. Metabolic changes in glucose, lipid, and amino acid levels are involved in glycolysis, the tricarboxylic acid cycle, the pentose phosphate pathway, the arachidonic acid metabolic pathway, and amino acid metabolism. These alterations in metabolic pathways and metabolites can fulfill bio-energetic requirements, promote cell proliferation, drive inflammatory mediator secretion, mediate leukocyte infiltration, induce joint destruction and muscle atrophy, and regulate cell proliferation, which may reflect the etiologies of RA. Differential metabolites can be used as biomarkers for the diagnosis, prognosis, and risk prediction, improving the specificity and accuracy of diagnostics and prognosis prediction. Additionally, metabolic changes associated with therapeutic responses can improve the understanding of drug mechanism. Metabolic homeostasis and regulation are new therapeutic strategies for RA. In this review, we provide a comprehensive overview of advances in metabolomics for RA.

A Review of Metabolomic Profiling in Rheumatoid Arthritis: Bringing New Insights in Disease Pathogenesis, Treatment and Comorbidities

Metabolomic analysis provides a wealth of information that can be predictive of distinctive phenotypes of pathogenic processes and has been applied to better understand disease development. Rheumatoid arthritis (RA) is an autoimmune disease with the establishment of chronic synovial inflammation that affects joints and peripheral tissues such as skeletal muscle and bone. There is a lack of useful disease biomarkers to track disease activity, drug response and follow-up in RA. In this review, we describe potential metabolic biomarkers that might be helpful in the study of RA pathogenesis, drug response and risk of comorbidities. TMAO (choline and trimethylamine oxide) and TCA (tricarboxylic acid) cycle products have been suggested to modulate metabolic profiles during the early stages of RA and are present systemically, which is a relevant characteristic for biomarkers. Moreover, the analysis of lipids such as cholesterol, FFAs and PUFAs may provide important information before disease onset to predict disease activity and treatment response. Regarding therapeutics, TNF inhibitors may increase the levels of tryptophan, valine, lysine, creatinine and alanine, whereas JAK/STAT inhibitors may modulate exclusively fatty acids. These observations indicate that different disease modifying antirheumatic drugs have specific metabolic profiles and can reveal differences between responders and non-responders. In terms of comorbidities, physical impairment represented by higher fatigue scores and muscle wasting has been associated with an increase in urea cycle, FFAs, tocopherols and BCAAs. In conclusion, synovial fluid, blood and urine samples from RA patients seem to provide critical information about the metabolic profile related to drug response, disease activity and comorbidities.

Metabolomics in Autoimmune Diseases: Focus on Rheumatoid Arthritis, Systemic Lupus Erythematous, and Multiple Sclerosis

The metabolomics approach represents the last downstream phenotype and is widely used in clinical studies and drug discovery. In this paper, we outline recent advances in the metabolomics research of autoimmune diseases (ADs) such as rheumatoid arthritis (RA), multiple sclerosis (MuS), and systemic lupus erythematosus (SLE). The newly discovered biomarkers and the metabolic mechanism studies for these ADs are described here. In addition, studies elucidating the metabolic mechanisms underlying these ADs are presented. Metabolomics has the potential to contribute to pharmacotherapy personalization; thus, we summarize the biomarker studies performed to predict the personalization of medicine and drug response.

Circulating Pro- and Anti-Inflammatory Metabolites and Its Potential Role in Rheumatoid Arthritis Pathogenesis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that affects synovial joints, leading to inflammation, joint destruction, loss of function, and disability. Although recent pharmaceutical advances have improved the treatment of RA, patients often inquire about dietary interventions to improve RA symptoms, as they perceive pain and/or swelling after the consumption or avoidance of certain foods. There is evidence that some foods have pro- or anti-inflammatory effects mediated by diet-related metabolites. In addition, recent literature has shown a link between diet-related metabolites and microbiome changes, since the gut microbiome is involved in the metabolism of some dietary ingredients. But diet and the gut microbiome are not the only factors linked to circulating pro- and anti-inflammatory metabolites. Other factors including smoking, associated comorbidities, and therapeutic drugs might also modify the circulating metabolomic profile and play a role in RA pathogenesis. This article summarizes what is known about circulating pro- and anti-inflammatory metabolites in RA. It also emphasizes factors that might be involved in their circulating concentrations and diet-related metabolites with a beneficial effect in RA.

Changes in the Canine Plasma Lipidome after Short- and Long-Term Excess Glucocorticoid Exposure

Glucocorticoids (GCs) are critical regulators of metabolic control in mammals and their aberrant function has been linked to several pathologies. GCs are widely used in human and veterinary clinical practice as potent anti-inflammatory and immune suppressive agents. Dyslipidaemia is a frequently observed consequence of GC treatment, typified by increased lipolysis, lipid mobilization, liponeogenesis, and adipogenesis. Dogs with excess GC show hyperlipidaemia, hypertension, and a higher risk of developing type 2 diabetes mellitus, but the risk of developing atherosclerotic lesions is low as compared to humans. This study aimed to examine alterations in the canine plasma lipidome in a model of experimentally induced short-term and long-term GC excess. Both treatments led to significant plasma lipidome alterations, which were more pronounced after long-term excess steroid exposure. In particular, monohexosylceramides, phosphatidylinositols, ether phosphatidylcholines, acyl phosphatidylcholines, triacylglycerols and sphingosine 1-phosphates showed significant changes. The present study highlights the hitherto unknown effects of GCs on lipid metabolism, which will be important in the further elucidation of the role and function of GCs as drugs and in metabolic and cardiovascular diseases.