POS0056 GLOBAL STEROID METABOLISM IN MACROPHAGES: SHAPING INFLAMMATORY FUNCTION AND DISEASE ACTIVITY IN RHEUMATOID ARTHRITIS

Background

Macrophages are key drivers of joint destruction and disease pathophysiology in rheumatoid arthritis (RA), where their inflammatory function is influenced by steroid hormones such as androgens and glucocorticoids (GCs). Local bioavailability of these steroids is determined by both systemic adrenal/gonadal synthesis and local metabolism in peripheral target tissues. The inflammatory regulation and function of steroid hormone metabolism by key rate limiting enzymes in chronic inflammatory diseases such as RA remain poorly defined and could present new therapeutic targets.

Objectives

Characterise regulation of global steroid metabolism in macrophages in RA and determine its contribution to androgen and GC availability, macrophage function and disease activity.

Methods

Bulk and single cell RNA-sequencing of FACS-sorted macrophages were analysed using previously published datasets from RA patients (27 female, 8 male)(1, 2). Gene expression of rate limiting steroid metabolism enzymes were assessed in macrophages and their subsets and correlated to clinical parameters of disease activity. Primary human monocyte-derived macrophages were polarised to non-inflammatory (M-CSF 20ng/ml) and inflammatory activated (M-CSF 20ng/ml, IFNγ 20ng/ml, TNFα 10ng/ml) subsets and treated with active or inactive metabolites of GCs (cortisol/cortisone 100nmol/l) and androgens (androstenedione/testosterone/DHEA 100nmol/l; DHT 10nmol/l). Metabolism and functional effects were assessed in primary cultures and RA synovial fluids by liquid chromatography mass spectrometry, RT-qPCR and ELISA.

Results

Significant differentially expressed genes (DEGs) were identified in the GC and androgen metabolism pathways in synovial macrophages when stratified for high and low disease activity by DAS28-CRP. Expression of the GC-activating enzyme HSD11B1 and androgen activating enzyme SRD5A1 were significantly increased and positively correlated with disease severity. The androgen activating enzyme AKR1C3 was significantly suppressed and negatively correlated with disease severity. SRD5A1 and HSD11B1 expression were localised to S100A12pos and SPP1pos subsets associated with active RA, whilst AKR1C3 was primarily expressed by MerTKposTREM2high subsets associated with RA remission. Inflammatory activation of primary macrophages decreased AKR1C3, and increased HSD11B1 and SRD5A1 expression. This resulted in a shift in intracrine production of active GCs and androgens favouring increased levels of the active GC cortisol and the potent androgen DHT. The resulting changes in steroid ratios in inflammatory activated macrophages resulted in lower expression and release of the pro-inflammatory mediators TNFα, IL6 and IL12 indicating functional significance. In vivo, metabolic changes favouring increased GC activation and reduced androgen activation correlated with disease severity determined by DAS28-CRP.

Conclusion

We have shown for the first time a role for macrophages and their tissue subsets in the inflammatory metabolism and activation of GCs and androgens in RA, which influence macrophage function and disease activity. Targeting these key metabolic pathways represents a novel route to modifying and suppressing disease activity and joint destruction in chronic polyarthritis.

References

[1]Zhang F, Wei K, Slowikowski K, Fonseka CY, Rao DA, Kelly S, et al. Defining inflammatory cell states in rheumatoid arthritis joint synovial tissues by integrating single-cell transcriptomics and mass cytometry. Nature Immunology. 2019;20(7):928-+.

[2]Alivernini S, MacDonald L, Elmesmari A, Finlay S, Tolusso B, Gigante MR, et al. Distinct synovial tissue macrophage subsets regulate inflammation and remission in rheumatoid arthritis. Nature Medicine. 2020;26(8):1295-+.

Acknowledgements

This research was funded by the Wellcome Trust (ref: 215243/Z/19/Z)

Disclosure of Interests

None declared

FIT & STRONG! PLUS: DESCRIPTIVE DEMOGRAPHIC AND RISK CHARACTERISTICS IN A COMPARATIVE EFFECTIVENESS TRIAL FOR OLDER AFRICAN-AMERICAN ADULTS WITH OSTEOARTHRITIS

Objectives

The prevalence of osteoarthritis (OA) has increased in the US. We report on a comparative effectiveness trial that compares Fit & Strong!, an existing evidence-based physical activity (PA) program, to Fit & Strong! Plus, which combines the Fit & Strong! intervention with a weight management intervention.

Methods

Participants included 413 overweight/obese (BMI 25-50 kg/m²) adults with lower extremity (LE) OA. The majority of the sample was African-American and female. Both interventions met 3 times weekly for 8 weeks. Primary measures included diet and weight.

Results

The baseline mean BMI for all participants was 34.8 kg/m^², percentage of calories from fat was high, and self-reported PA was low.

Discussion

This sample of overweight/obese African-American adults had lifestyle patterns at baseline that were less than healthful, and there were differences between self-report and performance-based measures as a function of age.

The KTx360°-study: a multicenter, multisectoral, multimodal, telemedicine-based follow-up care model to improve care and reduce health-care costs after kidney transplantation in children and adults

Background

Follow-up care after kidney transplantation is performed in transplant centers as well as in local nephrologist’s practices in Germany. However, organized integrated care of these different sectors of the German health care system is missing. This organizational deficit as well as non-adherence of kidney recipients and longterm cardiovascular complications are major reasons for an impaired patient and graft survival.

Methods

The KTx360° study is supported by a grant from the Federal Joint Committee of the Federal Republic of Germany.

The study will include 448 (39 children) incident patients of all ages with KTx after study start in May 2017 and 963 (83 children) prevalent patients with KTx between 2010 and 2016.

The collaboration between transplant centers and nephrologists in private local practices will be supported by internet-based case-files and scheduled virtual visits (patient consultation via video conferencing). At specified points of the care process patients will receive cardiovascular and adherence assessments and respective interventions. Care will be coordinated by an additional case management.

The goals of the study will be evaluated by an independent institute using claims data from the statutory health insurances and data collected from patients and their caregivers during study participation. To model longitudinal changes after transplantation and differences in changes and levels of immunosuppresive therapy after transplantation between study participants and historical data as well as data from control patients who do not participate in KTx360°, adjusted regression analyses, such as mixed models with repeated measures, will be used. Relevant confounders will be controlled in all analyses.

Discussion

The study aims to prolong patient and graft survival, to reduce avoidable hospitalizations, co-morbidities and health care costs, and to enhance quality of life of patients after kidney transplantation.

Trial registration

ISRCTN29416382 (retrospectively registered on 05.05.2017)

The steroid metabolite 16(β)-OH-androstenedione generated by CYP21A2 serves as a substrate for CYP19A1

The 21-hydroxylase (CYP21A2) is a steroidogenic enzyme crucial for the synthesis of mineralo- and glucocorticoids. It is described to convert progesterone as well as 17-OH-progesterone, through a hydroxylation at position C21, into 11-deoxycorticosterone (DOC) and 11-deoxycortisol (RSS), respectively. In this study we unraveled CYP21A2 to have a broader steroid substrate spectrum than assumed. Utilizing a reconstituted in vitro system, consisting of purified human CYP21A2 and human cytochrome P450 reductase (CPR) we demonstrated that CYP21A2 is capable to metabolize DOC, RSS, androstenedione (A4) and testosterone (T). In addition, the conversion of A4 rendered a product whose structure was elucidated through NMR spectroscopy, showing a hydroxylation at position C16-beta. The androgenic properties of this steroid metabolite, 16(β)-OH-androstenedione (16bOHA4), were investigated and compared with A4. Both steroid metabolites were shown to be weak agonists for the human androgen receptor. Moreover, the interaction of 16bOHA4 with the aromatase (CYP19A1) was compared to that of A4, indicating that the C16 hydroxyl group does not influence the binding with CYP19A1. In contrast, the elucidation of the kinetic parameters showed an increased K_m and decreased k_cat value resulting in a 2-fold decreased catalytic efficiency compared to A4. These findings were in accordance with our docking studies, revealing a similar binding conformation and distance to the heme iron of both steroids. Furthermore, the product of 16bOHA4, presumably 16-hydroxy-estrone (16bOHE1), was investigated with regard to its estrogenic activity, which was negligible compared to estradiol and estrone. Finally, 16bOHA4 was found to be present in a patient with 11-hydroxylase deficiency and in a patient with an endocrine tumor. Taken together, this study provides novel information on the steroid hormone biosynthesis and presents a new method to detect further potential relevant novel steroid metabolites.

[Rehabilitation after kidney transplantation: Old problems and new structures]

Kidney transplantation is currently the best therapeutic option for patients with end stage renal disease. Alternative treatment with hemo- or peritoneal dialysis is associated with higher comorbidities, higher morbidity/mortality, and reduced quality of life. Thus, a major aim in posttransplant care is to develop strategies to increase transplant survival and reduce known risk factors and comorbidities. In this overview, we propose a concept to include rehabilitation clinics in all aspects of the transplant process. This concept includes pretransplant care on the waiting list to prepare the patient for the transplant, the direct postoperative treatment phase, and repeated and risk adapted stays in rehabilitation clinics during long-term follow-up to address specific and individual problems.

CXCL13 as a new biomarker of systemic lupus erythematosus and lupus nephritis - from bench to bedside?

Different studies over the last decade have linked the B cell-attracting chemokine CXC ligand 13 (CXCL13) to the autoimmune disease systemic lupus erythematosus (SLE). A pathogenetic role of this chemokine for disease manifestation in SLE was described initially in mouse models for SLE. Mechanisms of CXCL13 actions were also identified in SLE patients. Moreover, various clinical studies have identified CXCL13 serum levels as a useful biomarker in patients with SLE of different ethnicities for disease activity. In addition, CXCL13 seems to be a promising marker for the diagnosis of lupus nephritis, one of the most severe complications of SLE. However, its exact place within the mechanisms that lead to SLE remains to be defined. Further research is needed to resolve more details of the pathomechanism and the signalling pathway of CXCL13 in SLE. Blocking CXCL13 or the signal pathways of CXCL13 is seen as a promising therapeutic approach for SLE and will be addressed in the near future. This review summarizes all papers that linked CXCL13 to SLE and highlights its importance in the pathogenesis and diagnosis of SLE.

Pathogenetic role of glomerular CXCL13 expression in lupus nephritis

Podocytes maintain the structure and function of the glomerular filtration barrier. However, podocytes have recently been implicated in the innate immune response, and their function as non-haematopoietic antigen-presenting cells was highlighted. We have shown previously that excessive expression of the chemokine CXCL13 is a distinctive early event for nephritis in a murine model of systemic lupus erythematosus (SLE). Furthermore, we found that CXCL13 is elevated significantly in the serum of patients with SLE-nephritis. In this study, we were able to show for the first time that (i) CXCL13 is expressed locally in glomeruli in a model for SLE-nephritis in mice and that (ii) incubation of human podocytes with CXCL13 induces receptor stimulation of CXCR5 with activation of signalling pathways, resulting in (iii) secretion of proinflammatory cytokines and chemokines in culture supernatant. This cytokine/chemokine cocktail can lead to (iv) a neutrophil respiratory burst in isolated human granulocytes. Taken together, our results provide further evidence that CXCL13 is involved in the pathogenesis of glomerulonephritis and that podocytes can play an active role in local proinflammatory immune responses. Thus, CXCL13 could be a direct target for the therapy of glomerulonephritis in general and for SLE-nephritis in particular.

CXCL13 as a novel marker for diagnosis and disease monitoring in pediatric PTLD

Posttransplant lymphoproliferative disease (PTLD) is a severe complication of immunosuppressive treatment in organ-grafted children. Early diagnosis of PTLD is hampered by both unspecific clinical symptoms and lack of easy accessible markers. The homeostatic chemokine CXCL13, which plays a crucial role in B-cell homing and lymphoid organ development, is expressed in some lymphomatous diseases. This study aims to investigate whether serum CXCL13 (sCXCL13) levels correlate with occurrence and regression of PTLD in pediatric solid-organ graft recipients. Serum samples from PTLD patients (n = 21), patients with Epstein-Barr virus (EBV) reactivation (n = 18), and healthy age-matched controls (n = 19) were tested for CXCL13 using a commercially available ELISA kit. sCXCL13 levels were significantly higher in PTLD patients than in healthy children. PTLD patients had also higher sCXCL13 values than pediatric solid-organ recipients with EBV reactivation. An increase in sCXCL13 levels was observed from EBV reactivation to PTLD diagnosis in most cases. Elevated sCXCL13 levels were detected up to 2 years prior to PTLD diagnosis and correlated well with response to cytoreductive treatment in individual patients. sCXCL13, thus, may be a readily available surrogate marker for the diagnosis of PTLD and for monitoring of response to treatment in patients with initially elevated sCXCL13 levels.

Elevation of serum CXCL13 in SLE as well as in sepsis

Recent studies have demonstrated that CXCL13 serum levels correlate significantly with systemic lupus erythematosus (SLE) disease activity. However, experimental studies show that CXCL13 production can also be induced by bacterial exposure as well as in response to inflammatory cytokines. This report asks whether CXCL13 serum levels are elevated in patients with evidence of bacterial infections and whether there is a correlation with the C-reactive protein (CRP) levels or the severity of illness in critically ill patients. CXCL13 levels were compared in 39 patients with active SLE (without concomitant infection), 40 non-SLE patients with sepsis, and 40 healthy controls by enzyme-linked immunosorbent assay (ELISA) methodology. We also tested storage conditions and freeze–thaw cycles for stability of CXCL13 in serum samples. Our studies demonstrated that the median CXCL13 serum levels were significantly elevated in patients with SLE [median 83 pg/ml (interquartile range 38–366)] or sepsis [359 pg/ml (151–459)] compared with healthy controls [32 pg/ml (27–41), p < 0.001]. The CXCL13 serum levels correlated with disease activity in SLE (CXCL13 vs. SLEDAI r = 0.65, p < 0.001), but were not associated with severity of illness score in critically ill patients (CXCL13 vs. SOFA r = −0.15, p = 0.35). However, CXCL13 serum levels were clearly associated with CRP levels in both sepsis ( r = 0.45, p = 0.003) and SLE ( r = 0.39, p = 0.02). In conclusion, CXCL13 is a stable serum marker for disease activity in SLE patients, but concomitant infections can also lead to increased CXCL13 levels.

Oats and soy in lipid-lowering diets for women with hypercholesterolemia: is there synergy?

OBJECTIVES

To study possible synergistic effects of oats and soy on reducing total and low-density lipoprotein cholesterol (LDL-C) concentrations in human beings and the efficacy and feasibility of including these adjustments to a National Cholesterol Education Program Step I diet. SUBJECT/SETTING: One hundred twenty-seven postmenopausal women with moderate hypercholesterolemia were recruited from a large Midwestern workforce and senior centers in the surrounding community. Intervention and clinical visits were conducted in these same facilities.

DESIGN

After a 3-week lead-in period on the Step I diet, participants were randomly assigned to 1 of 4 dietary treatments for an additional 6 weeks: an oats/milk group, a wheat/soy group, an oats/soy group, and a wheat/milk group. Clinical measurements included blood draws, body weight and height, blood pressure, and medical history data. Three-day food records were collected at baseline and Weeks 3 and 9 of the intervention. Randomization was stratified based on the status of hormone replacement therapy and was blocked with sizes 4 or 8 for group assignment.

RESULTS

After 3 weeks on the Step I diet, total cholesterol, LDL-C, and triglyceride levels; total fat and saturated fat intake, dietary cholesterol intake, Keys score, and body mass index were all reduced. Following an additional 6 weeks on the Step I diet plus intervention, total cholesterol and LDL-C were further reduced for both the oats/soy group and oats/milk group. There were no significant further changes in total cholesterol, LDL-C, or high-density lipoprotein cholesterol levels in the wheat/soy and wheat/milk groups. Body mass index remained stable in all groups from Week 3 to Week 9.

APPLICATIONS

Nonpharmacologic dietary interventions like the Step I diet are feasible in a community setting and can produce rapid and significant lipid-lowering benefits. Daily consumption of 2 servings of oats can contribute to further lipid alterations in this population although soy intake at this dose may not. Palatability and convenience are important considerations in achieving dietary adherence.

Brain-tumor cell kinetics correlated with survival

In a review of 38 glioblastoma patients for whom fresh tissue kinetic data were available before any therapy was instituted, no correlation between the labeling index and survival time could be statistically determined. This relationship seems entirely consistent with the published theoretical determinants of tumor behavior: that is, altered ability for growth arrest and differentiation, constantly evolving mutant sublines, genetic instability, and an ever-changing metabolic and vascular environment.

The measurement of extracellular water volumes in tissues by gadolinium modification of 1H-NMR spin lattice (T1) relaxation

The present studies were conducted in RIF-1, M5076 and Panc02 murine tumor models to compare extracellular water measurements made by 51Cr-EDTA dilution techniques and a new method which exploits the concentration dependent modification of 1H-NMR proton relaxation by Gadolinium-DTPA-dimethyl glucamine (Gd-DTPA-dimeg) in plasma and tissues. The time dependent changes in T1 modification in tissue and plasma were determined at various intervals after i.v. injection of 0.1 ml of 100 mM Gd-DTPA-dimeg and Gd concentrations determined from standard curves of Gd concentration dependent T1 modification of mouse plasma. Comparison of tissue and plasma Gd concentrations permitted the calculation of Gd-DTPA-dimeg distribution volumes. In unperturbed RIF-1, M5076 and Panc02 tumors, Gd-DTPA-dimeg distribution volumes determined by the T1 modification technique were similar to extracellular water spaces determined by 51Cr-EDTA dilution assays. In mouse liver, the 51Cr-EDTA assay resulted in artifactually high extracellular water space estimates due to internalization of the probe; Gd-DTPA-dimeg distribution volumes determined in liver with both the 153Gd-DTPA-dimeg and by the T1 modification method were approximately 150 ul/gram. The Gd-DTPA-dimeg T1 modification method also provided good approximations of changes in extracellular water volumes in RIF-1 tumors after dexamethasone and cyclophosphamide treatments. These results indicate that Gd-DTPA-dimeg modification of proton relaxation may be extremely useful for monitoring changes in tumor water dynamics during cancer therapy.