Genome-Wide Genetic Analysis of Dropout in a Controlled Exercise Intervention in Sedentary Adults With Overweight or Obesity and Cardiometabolic Disease

BACKGROUND

Despite the benefits of exercise, many individuals are unable or unwilling to adopt an exercise intervention.

PURPOSE

The purpose of this analysis was to identify putative genetic variants associated with dropout from exercise training interventions among individuals in the STRRIDE trials.

METHODS

We used a genome-wide association study approach to identify genetic variants in 603 participants initiating a supervised exercise intervention. Exercise intervention dropout occurred when a subject withdrew from further participation in the study or was otherwise lost to follow-up.

RESULTS

Exercise intervention dropout was associated with a cluster of single-nucleotide polymorphisms with the top candidate being rs722069 (T/C, risk allele = C) (unadjusted p = 2.2 × 10-7, odds ratio = 2.23) contained within a linkage disequilibrium block on chromosome 16. In Genotype-Tissue Expression, rs722069 is an expression quantitative trait locus of the EARS2, COG7, and DCTN5 genes in skeletal muscle tissue. In subsets of the STRRIDE genetic cohort with available muscle gene expression (n = 37) and metabolic data (n = 82), at baseline the C allele was associated with lesser muscle expression of EARS2 (p < .002) and COG7 (p = .074) as well as lesser muscle concentrations of C2- and C3-acylcarnitines (p = .026).

CONCLUSIONS

Our observations imply that exercise intervention dropout is genetically moderated through alterations in gene expression and metabolic pathways in skeletal muscle. Individual genetic traits may allow the development of a biomarker-based approach for identifying individuals who may benefit from more intensive counseling and other interventions to optimize exercise intervention adoption.

CLINICAL TRIAL INFORMATION

STRRIDE I = NCT00200993; STRRIDE AT/RT = NCT00275145; STRRIDE-PD = NCT00962962.

Mycophenolate mofetil inhibits Merkel cell carcinoma growth

The direct antitumour effects of mTOR inhibitors against cutaneous squamous cell carcinoma (SCC) have prompted a paradigm shift towards using sirolimus for allograft rejection prophylaxis in patients with high-risk SCC who have had a solid organ transplant (SOT). Patients who have had an SOT are at higher risk for Merkel cell carcinoma (MCC), yet there is little evidence concerning potential antitumour effects of immunosuppressive drugs against MCC. Screening seven immunosuppressive drugs in six MCC cell lines revealed that mycophenolate mofetil (MMF) had strong antitumour activity (surpassing mTOR inhibitors) and higher potency in MCC vs. other cancer types. MMF also inhibited MCC tumour growth in mice. Our preclinical findings strongly suggest the utility of MMF in patients with MCC who require immunosuppression.

Digital biobanks are underutilized in dermatology and create opportunities to reduce the burden of skin disease

Digital biobanks that integrate genetic data with health data captured by digital sources are used routinely to discover genes, biomarkers, gene–environment interactions and pharmacogenetic relationships across many clinical areas. There remain many opportunities in dermatology to further use biobank data to increase our knowledge about the genetic architecture of skin disease, to resolve disease mechanisms that can be modulated by medical interventions and to discover genetically derived disease relationships that inform on drug repurposing and adverse events. Such knowledge promises to reduce the global burden of skin disease and facilitates the development of tailored medical care.

Participant-guided development of bilingual genomic educational infographics for Electronic Medical Records and Genomics Phase IV study

OBJECTIVE

Developing targeted, culturally competent educational materials is critical for participant understanding of engagement in a large genomic study that uses computational pipelines to produce genome-informed risk assessments.

MATERIALS AND METHODS

Guided by the Smerecnik framework that theorizes understanding of multifactorial genetic disease through 3 knowledge types, we developed English and Spanish infographics for individuals enrolled in the Electronic Medical Records and Genomics Network. Infographics were developed to explain concepts in lay language and visualizations. We conducted iterative sessions using a modified "think-aloud" process with 10 participants (6 English, 4 Spanish-speaking) to explore comprehension of and attitudes towards the infographics.

RESULTS

We found that all but one participant had "awareness knowledge" of genetic disease risk factors upon viewing the infographics. Many participants had difficulty with "how-to" knowledge of applying genetic risk factors to specific monogenic and polygenic risks. Participant attitudes towards the iteratively-refined infographics indicated that design saturation was reached.

DISCUSSION

There were several elements that contributed to the participants' comprehension (or misunderstanding) of the infographics. Visualization and iconography techniques best resonated with those who could draw on prior experiences or knowledge and were absent in those without. Limited graphicacy interfered with the understanding of absolute and relative risks when presented in graph format. Notably, narrative and storytelling theory that informed the creation of a vignette infographic was most accessible to all participants.

CONCLUSION

Engagement with the intended audience who can identify strengths and points for improvement of the intervention is necessary to the development of effective infographics.

Implications of the accuracy of diagnostic algorithms for systemic lupus on our understanding of racial disparities in pregnancy outcomes

OBJECTIVE

Disparities in pregnancy outcomes among women with SLE remain understudied, with few available racially diverse datasets. We sought to identify disparities between Black and White women in pregnancy outcomes within academic institutions in the United States.

METHODS

Using the Common Data Model electronic medical record (EMR)-based datasets within the Carolinas Collaborative, we identified women with pregnancy delivery data (2014-2019) and ≥1 SLE International Classification of Diseases 9 or 10 code (ICD9/10) code. From this dataset, we identified four cohorts of SLE pregnancies, three based on EMR-based algorithms and one confirmed with chart review. We compared the pregnancy outcomes identified in each of these cohorts for Black and White women.

RESULTS

Of 172 pregnancies in women with ≥1 SLE ICD9/10 code, 49% had confirmed SLE. Adverse pregnancy outcomes occurred in 40% of pregnancies in women with ≥1 ICD9/10 SLE code and 52% of pregnancies with confirmed SLE. SLE was frequently over-diagnosed in women who were White, resulting in 40-75% lower rates of adverse pregnancy outcomes in EMR-derived vs confirmed SLE cohorts. Over-diagnosis was less common for Black women with pregnancy outcomes 12-20% lower in EMR-derived vs confirmed SLE cohorts. Black women had higher rates of adverse pregnancy outcomes than White women in the EMR-derived, but not the confirmed cohorts.

CONCLUSION

EMR-derived cohorts of pregnancies in women who are Black, but not White, provided accurate estimations of pregnancy outcomes. The data from the confirmed SLE pregnancies suggest that all women with SLE, regardless of race, referred to academic centres remain at very high risk for adverse pregnancy outcome.

Mechanisms of Ovarian Cancer-Associated Cachexia

Cancer-associated cachexia occurs in 50% to 80% of cancer patients and is responsible for 20% to 30% of cancer-related deaths. Cachexia limits survival and treatment outcomes, and is a major contributor to morbidity and mortality during cancer. Ovarian cancer is one of the leading causes of cancer-related deaths in women, and recent studies have begun to highlight the prevalence and clinical impact of cachexia in this population. Here, we review the existing understanding of cachexia pathophysiology and summarize relevant studies assessing ovarian cancer-associated cachexia in clinical and preclinical studies. In clinical studies, there is increased evidence that reduced skeletal muscle mass and quality associate with worse outcomes in subjects with ovarian cancer. Mouse models of ovarian cancer display cachexia, often characterized by muscle and fat wasting alongside inflammation, although they remain underexplored relative to other cachexia-associated cancer types. Certain soluble factors have been identified and successfully targeted in these models, providing novel therapeutic targets for mitigating cachexia during ovarian cancer. However, given the relatively low number of studies, the translational relevance of these findings is yet to be determined and requires more research. Overall, our current understanding of ovarian cancer-associated cachexia is insufficient and this review highlights the need for future research specifically aimed at exploring mechanisms of ovarian cancer-associated cachexia by using unbiased approaches and animal models representative of the clinical landscape of ovarian cancer.

Electroconductivity, a regenerative engineering approach to reverse rotator cuff muscle degeneration

Muscle degeneration is one the main factors that lead to the high rate of retear after a successful repair of rotator cuff (RC) tears. The current surgical practices have failed to treat patients with chronic massive rotator cuff tears (RCTs). Therefore, regenerative engineering approaches are being studied to address the challenges. Recent studies showed the promising outcomes of electroactive materials (EAMs) on the regeneration of electrically excitable tissues such as skeletal muscle. Here, we review the most important biological mechanism of RC muscle degeneration. Further, the review covers the recent studies on EAMs for muscle regeneration including RC muscle. Finally, we will discuss the future direction toward the application of EAMs for the augmentation of RCTs.

Performance of the 2016 ACR-EULAR myositis response criteria in juvenile dermatomyositis therapeutic trials and consensus profiles

OBJECTIVES

The 2016 ACR-EULAR Response Criteria for JDM was developed as a composite measure with differential weights of six core set measures (CSMs) to calculate a Total Improvement Score (TIS). We assessed the contribution of each CSM, representation of muscle-related and patient-reported CSMs towards improvement, and frequency of CSM worsening across myositis response criteria (MRC) categories in validation of MRC.

METHODS

Data from JDM patients in the Rituximab in Myositis trial (n = 48), PRINTO JDM trial (n = 139), and consensus patient profiles (n = 273) were included. Observed vs expected CSM contributions were compared using Sign test. Characteristics of MRC categories were compared by Wilcoxon tests with Bonferroni adjustment. Spearman correlation of changes in TIS and individual CSMs were examined. Agreement between physician-assessed change and MRC categories was evaluated by weighted Cohen's kappa.

RESULTS

Of 457 JDM patients with IMACS CSMs and 380 with PRINTO CSMs, 9-13% had minimal, 19-23% had moderate and 41-50% had major improvement. The number of improved and absolute percentage change of CSMs increased by MRC improvement level. Patients with minimal improvement by MRC had a median of 0-1 CSM worsened, and those with moderate/major improvement had a median of zero worsening CSMs. Of patients improved by MRC, 94-95% had improvement in muscle strength and 93-95% had improvement in ≥1 patient-reported CSM. IMACS and PRINTO CSMs performed similarly. Physician-rated change and MRC improvement categories had moderate-to-substantial agreement (Kappa 0.5-0.7).

CONCLUSION

The ACR-EULAR MRC perform consistently across multiple studies, supporting its further use as an efficacy end point in JDM trials.

CONQUER Scleroderma: association of gastrointestinal tract symptoms in early disease with resource utilization

OBJECTIVES

SSc is associated with increased health-care resource utilization and economic burden. The Collaborative National Quality and Efficacy Registry (CONQUER) is a US-based collaborative that collects longitudinal follow-up data on SSc patients with <5 years of disease duration enrolled at scleroderma centres in the USA. The objective of this study was to investigate the relationship between gastrointestinal tract symptoms and self-reported resource utilization in CONQUER participants.

METHODS

CONQUER participants who had completed a baseline and 12-month Gastrointestinal Tract Questionnaire (GIT 2.0) and a Resource Utilization Questionnaire (RUQ) were included in this analysis. Patients were categorized by total GIT 2.0 severity: none-to-mild (0-0.49); moderate (0.50-1.00), and severe-to-very severe (1.01-3.00). Clinical features and medication exposures were examined in each of these categories. The 12-month RUQ responses were summarized by GIT 2.0 score categories at 12 months.

RESULTS

Among the 211 CONQUER participants who met the inclusion criteria, most (64%) had mild GIT symptoms, 26% had moderate symptoms, and 10% severe GIT symptoms at 12 months. The categorization of GIT total severity score by RUQ showed that more upper endoscopy procedures and inpatient hospitalization occurred in the CONQUER participants with severe GIT symptoms. These patients with severe GIT symptoms also reported the use of more adaptive equipment.

CONCLUSION

This report from the CONQUER cohort suggests that severe GIT symptoms result in more resource utilization. It is especially important to understand resource utilization in early disease cohorts when disease activity, rather than damage, primarily contributes to health-related costs of SSc.

Improved lung cancer clinical outcomes in patients with autoimmune rheumatic diseases

PURPOSE

Concomitant autoimmune rheumatic diseases (ARD) can add morbidity and complicate treatment decisions for patients with lung cancer. We evaluated the tumour characteristics at diagnosis and clinical outcomes in lung cancer patients with or without ARD.

METHODS

This retrospective cohort study included 10 963 patients with lung cancer, treated at Johns Hopkins. Clinical data including tumour characteristics and outcomes were extracted from the cancer registry. Data on patients' history of 20 ARD were extracted from the electronic medical record. Logistic regression was used to compare tumour characteristics between those with and without ARD; Kaplan-Meier curves and Cox proportional hazards models were performed to compare survival outcomes.

RESULTS

ARD was present in 3.6% of patients (n=454). The mean age at diagnosis was 69 (SD 10) and 68 (SD 12) in patients with and without ARD (p=0.02). Female sex and smoking history were significantly associated with a history of ARD (OR: 1.75, OR: 1.46, p<0.05). Patients with ARD were more likely to be diagnosed with stage 1 lung cancer (36.8% vs 26.9%, p<0.001) and with smaller tumour size (OR: 0.76, p=0.01), controlling for sex, race and histology. Notably, lung cancer patients with ARD had a significantly prolonged median overall survival (OS) (7.11 years vs 1.7 years, p<0.001), independent of stage.

CONCLUSION

Patients with ARD and lung cancer had better OS compared with their counterparts, independent of cancer stage and treatments and were less likely to have advanced stage lung cancer at diagnosis. Additional studies are needed to investigate the differential immunological anti-tumour immune activity and genomic variations in patients with and without ARD.

MyD88 dimerization inhibitor ST2825 targets the aggressiveness of synovial fibroblasts in rheumatoid arthritis patients

BACKGROUND

Dimerization of the myeloid differentiation primary response 88 protein (MyD88) plays a pivotal role in the exacerbated response to innate immunity-dependent signaling in rheumatoid arthritis (RA). ST2825 is a highly specific inhibitor of MyD88 dimerization, previously shown to inhibit the pro-inflammatory gene expression in peripheral blood mononuclear cells from RA patients (RA PBMC). In this study, we elucidated the effect of disrupting MyD88 dimerization by ST2825 on the pathological properties of synovial fibroblasts from RA patients (RA SFs).

METHODS

RA SFs were treated with varying concentrations of ST2825 in the presence or absence of bacterial lipopolysaccharides (LPS) to activate innate immunity-dependent TLR signaling. The DNA content of the RA SFs was quantified by imaging cytometry to investigate the effect of ST2825 on different phases of the cell cycle and apoptosis. RNA-seq was used to assess the global response of the RA SF toward ST2825. The invasiveness of RA SFs in Matrigel matrices was measured in organoid cultures. SFs from osteoarthritis (OA SFs) patients and healthy dermal fibroblasts were used as controls.

RESULTS

ST2825 reduced the proliferation of SFs by arresting the cells in the G0/G1 phase of the cell cycle. In support of this finding, transcriptomic analysis by RNA-seq showed that ST2825 may have induced cell cycle arrest by primarily inhibiting the expression of critical cell cycle regulators Cyclin E2 and members of the E2F family transcription factors. Concurrently, ST2825 also downregulated the genes encoding for pain, inflammation, and joint catabolism mediators while upregulating the genes required for the translocation of nuclear proteins into the mitochondria and members of the mitochondrial respiratory complex 1. Finally, we demonstrated that ST2825 inhibited the invasiveness of RA SFs, by showing decreased migration of LPS-treated RA SFs in spheroid cultures.

CONCLUSIONS

The pathological properties of the RA SFs, in terms of their aberrant proliferation, increased invasiveness, upregulation of pain and inflammation mediators, and disruption of mitochondrial homeostasis, were attenuated by ST2825 treatment. Taken together with the previously reported anti-inflammatory effects of ST2825 in RA PBMC, this study strongly suggests that targeting MyD88 dimerization could mitigate both systemic and synovial pathologies in a variety of inflammatory arthritic diseases.

ZIC1 Dictates Osteogenesis Versus Adipogenesis in Human Mesenchymal Progenitor Cells Via a Hedgehog Dependent Mechanism

Numerous intrinsic factors regulate mesenchymal progenitor commitment to a specific cell fate, such as osteogenic or adipogenic lineages. Identification and modulation of novel intrinsic regulatory factors represent an opportunity to harness the regenerative potential of mesenchymal progenitors. In the present study, the transcription factor (TF) ZIC1 was identified to be differentially expressed among adipose compared with skeletal-derived mesenchymal progenitor cells. We observed that ZIC1 overexpression in human mesenchymal progenitors promotes osteogenesis and prevents adipogenesis. ZIC1 knockdown demonstrated the converse effects on cell differentiation. ZIC1 misexpression was associated with altered Hedgehog signaling, and the Hedgehog antagonist cyclopamine reversed the osteo/adipogenic differentiation alterations associated with ZIC1 overexpression. Finally, human mesenchymal progenitor cells with or without ZIC1 overexpression were implanted in an ossicle assay in NOD-SCID gamma mice. ZIC1 overexpression led to significantly increased ossicle formation in comparison to the control, as assessed by radiographic and histologic measures. Together, these data suggest that ZIC1 represents a TF at the center of osteo/adipogenic cell fate determinations-findings that have relevance in the fields of stem cell biology and therapeutic regenerative medicine.

Potential bias and lack of generalizability in electronic health record data: reflections on health equity from the National Institutes of Health Pragmatic Trials Collaboratory

Embedded pragmatic clinical trials (ePCTs) play a vital role in addressing current population health problems, and their use of electronic health record (EHR) systems promises efficiencies that will increase the speed and volume of relevant and generalizable research. However, as the number of ePCTs using EHR-derived data grows, so does the risk that research will become more vulnerable to biases due to differences in data capture and access to care for different subsets of the population, thereby propagating inequities in health and the healthcare system. We identify 3 challenges-incomplete and variable capture of data on social determinants of health, lack of representation of vulnerable populations that do not access or receive treatment, and data loss due to variable use of technology-that exacerbate bias when working with EHR data and offer recommendations and examples of ways to actively mitigate bias.

A novel ELOVL4 variant, L168S, causes early childhood-onset Spinocerebellar ataxia-34 and retinal dysfunction: a case report

Spinocerebellar ataxia 34 (SCA34) is an autosomal dominant inherited disease characterized by age-related cerebellar degeneration and ataxia caused by mutations in the Elongation of Very Long Chain Fatty Acid-4 (ELOVL4) gene. The ELOVL4 enzyme catalyzes the biosynthesis of both very long chain saturated fatty acids (VLC-SFA) and very long chain polyunsaturated fatty acids (VLC-PUFA) that are important for neuronal, reproductive, and skin function. Several variants in ELOVL4 have been shown to cause different tissue-specific disorders including SCA34 with or without Erythrokeratodermia Variabilis (EKV), a skin condition characterized by dry, scaly skin, Autosomal Dominant Stargardt-Like Macular Dystrophy (STGD3), and seizures associated with neuro-ichthyotic disorders. What is puzzling is how different mutations in the same gene seem to cause different tissue-specific disorders. To date, no SCA34 patients have presented with both SCA34 and STGD3 pathology that is caused by ELOVL4 variants that cause truncation of ELOVL4. Here, we report a novel case of an early childhood onset and rapidly progressive cerebellar degeneration and retinal dysfunction in a Belgian-Italian girl who developed severe dysarthria and gait problems starting at about 3.5 years of age and progressed to immobility by 4.5 years of age. Brain magnetic resonance imaging (MRI) revealed progressive vermian, cerebellar, cortical atrophy, progressive corpus callosum slimming, and hot cross bun sign visible on the MRI. Ophthalmological examinations also revealed progressive macular dysfunction as measured by electroretinography. Using exome sequencing, we identified a novel heterozygous ELOVL4 variant, c.503 T > C (p. L168S) in the patient. To understand the enzymatic function of this novel ELOVL4 variant and how it alters the levels of VLC-PUFA and VLC-SFA biosynthesis to contribute to cerebellar and retinal dysfunction, we expressed wild-type ELOVL4 or the L168S ELOVL4 variant in cell culture and supplemented the cultures with VLC-PUFA or VLC-SFA precursors. We showed that the L168S ELOVL4 variant is deficient in the biosynthesis of VLC-SFA and VLC-PUFA. Our work suggests that differential depletion of these fatty acids may be a contributing factor to the pathogenic mechanism of SCA34 with or without EKV. Further studies will help further define how the different ELOVL4 variants cause different tissue-specific disorders with variable ages of onset.

Aldehyde Dehydrogenase, a Marker of Normal and Malignant Stem Cells, Typifies Mesenchymal Progenitors in Perivascular Niches

Innate mesenchymal stem cells exhibiting multilineage differentiation and tissue (re)generative-or pathogenic-properties reside in perivascular niches. Subsets of these progenitors are committed to either osteo-, adipo-, or fibrogenesis, suggesting the existence of a developmental organization in blood vessel walls. We evaluated herein the activity of aldehyde dehydrogenase, a family of enzymes catalyzing the oxidation of aldehydes into carboxylic acids and a reported biomarker of normal and malignant stem cells, within human adipose tissue perivascular areas. A progression of ALDHLow to ALDHHigh CD34+ cells was identified in the tunica adventitia. Mesenchymal stem cell potential was confined to ALDHHigh cells, as assessed by proliferation and multilineage differentiation in vitro of cells sorted by flow cytometry with a fluorescent ALDH substrate. RNA sequencing confirmed and validated that ALDHHigh cells have a progenitor cell phenotype and provided evidence that the main isoform in this fraction is ALDH1A1, which was confirmed by immunohistochemistry. This demonstrates that ALDH activity, which marks hematopoietic progenitors and stem cells in diverse malignant tumors, also typifies native, blood vessel resident mesenchymal stem cells.

Mechanisms of Skeletal Muscle Atrophy and Molecular Circuitry of Stem Cell Fate in Skeletal Muscle Regeneration and Aging

Skeletal muscle is a complex and highly adaptable tissue. With aging, there is a progressive loss of muscle mass and function, known as sarcopenia, and a reduced capacity for regeneration and repair following injury. A review of the literature shows that the primary mechanisms underlying the age-related loss of muscle mass and the attenuated growth response are multi-factorial and related to alterations in multiple processes, including proteostasis, mitochondrial function, extracellular matrix remodeling, and neuromuscular junction function. Multiple factors influence the rate of sarcopenia, including acute illness and trauma, followed by incomplete recovery and repair. Regeneration and repair of damaged skeletal muscle involve an orchestrated cross-talk between multiple cell populations, including satellite cells, immune cells, and fibro-adipogenic precursor cells. Proof-of-concept studies in mice have demonstrated that reprogramming of this disrupted orchestration, resulting in the normalization of muscle function, may be possible using small molecules that target muscle macrophages. During aging, as well as in muscular dystrophies, disruptions in multiple signaling pathways and in the cross-talk between different cell populations contribute to the failure to properly repair and maintain muscle mass and function.

Total cortical interstitial inflammation predicts chronic kidney disease progression in patients with lupus nephritis

BACKGROUND

End-stage kidney disease (ESKD) from lupus nephritis (LN) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Kidney biopsy is the gold standard for diagnosis and prognostication of LN. While interstitial fibrosis and tubular atrophy (IFTA) predict progression to ESKD, the National Institutes of Health (NIH) classification of interstitial inflammation in unscarred cortical parenchyma is not predictive of chronic kidney disease (CKD) progression. The objective of this study was to determine whether total cortical interstitial inflammation that accounts for inflammation in the entire cortical parenchyma could predict CKD progression in patients with LN. Early identification of at-risk patients may improve outcomes.

METHODS

This retrospective cohort study included 125 SLE patients with LN class III, IV, V or mixed (III/V, IV/V) on the index biopsy (2005-2018). Kidney biopsies were reviewed and assigned based on the 2018 NIH Activity Index (AI) and tubulointerstitial lesion categories. Total interstitial inflammation in the entire cortical parenchyma was graded as 0, 1, 2 or 3, corresponding to <10%, 10-25%, 26-50% and >50%, respectively, of the total cortical parenchyma containing an inflammatory infiltrate (similar to the definition used in the Banff total inflammation score). CKD progression was defined as an estimated glomerular filtration rate decrease of ≥30% within 5 years after the index biopsy. Kaplan-Meier survival curves and Cox proportional hazards models were performed to compare the two scoring systems, the total cortical intestinal inflammation score and the NIH interstitial inflammation score as predictors of CKD progression.

RESULTS

Of 125 patients, 46 experienced CKD progression; 21 of 46 subsequently developed ESKD, 28 (22.4%) had moderate-severe total cortical interstitial inflammation and 8 (6.4%) had moderate-severe NIH interstitial inflammation. There were no differences in baseline characteristics between progressors and nonprogressors. Total cortical interstitial inflammation was associated with CKD progression in time-dependent analyses [hazard ratio 2.45 (95% confidence interval 1.2-4.97)] adjusted for age at biopsy, race, sex, LN class and hypertensive vascular change on kidney biopsy. The NIH interstitial inflammation was not associated with CKD progression.

CONCLUSIONS

In contrast to the current NIH interstitial inflammation classification, accounting for interstitial inflammation in the entire cortical parenchyma allows identification of patients at risk for CKD progression in LN.

CHRNA5-A3-B4 and DRD2 Genes and Smoking Cessation Throughout Adulthood: A Longitudinal Study of Women

INTRODUCTION

Smoking cessation is more than 50% heritable. Genetic studies of smoking cessation have been limited by short-term follow-up or cross-sectional design.

AIMS AND METHODS

This study tests single nucleotide polymorphism (SNP) associations with cessation during long-term follow-up throughout adulthood in women. The secondary aim tests whether genetic associations differ by smoking intensity. Associations between 10 SNPs in CHRNA5, CHRNA3, CHRNB2, CHRNB4, DRD2, and COMT and the probability of smoking cessation over time were evaluated in two longitudinal cohort studies of female nurses, the Nurses' Health Study (NHS) (n = 10 017) and NHS-2 (n = 2793). Participant follow-up ranged from 2 to 38 years with data collected every 2 years.

RESULTS

Women with the minor allele of either CHRNA5 SNP rs16969968 or CHRNA3 SNP rs1051730 had lower odds of cessation throughout adulthood [OR = 0.93, p-value = .003]. Women had increased odds of cessation if they had the minor allele of CHRNA3 SNP rs578776 [OR = 1.17, p-value = .002]. The minor allele of DRD2 SNP rs1800497 was associated with lower odds of cessation in moderate-to-heavy smokers [OR = 0.92, p-value = .0183] but increased odds in light smokers [OR = 1.24, p-value = .096].

CONCLUSIONS

Some SNP associations with short-term smoking abstinence observed in prior studies were shown in the present study to persist throughout adulthood over decades of follow-up. Other SNP associations with short-term abstinence did not persist long-term. The secondary aim findings suggest genetic associations may differ by smoking intensity.

IMPLICATIONS

The results of the present study expand on previous studies of SNP associations in relation to short-term smoking cessation to demonstrate some of these SNPs were associated with smoking cessation throughout decades of follow-up, whereas other SNP associations with short-term abstinence did not persist long-term. The rate of relapse to smoking remains high for several years after quitting smoking, and many smokers experience multiple quit attempts and relapse episodes throughout adulthood. Understanding genetic associations with long-term cessation has potential importance for precision medicine approaches to long-term cessation management.

Systemic sclerosis associated interstitial lung disease: a conceptual framework for subclinical, clinical and progressive disease

OBJECTIVES

To establish a framework by which experts define disease subsets in systemic sclerosis associated interstitial lung disease (SSc-ILD).

METHODS

A conceptual framework for subclinical, clinical and progressive ILD was provided to 83 experts, asking them to use the framework and classify actual SSc-ILD patients. Each patient profile was designed to be classified by at least four experts in terms of severity and risk of progression at baseline; progression was based on 1-year follow-up data. A consensus was reached if ≥75% of experts agreed. Experts provided information on which items were important in determining classification.

RESULTS

Forty-four experts (53%) completed the survey. Consensus was achieved on the dimensions of severity (75%, 60 of 80 profiles), risk of progression (71%, 57 of 80 profiles) and progressive ILD (60%, 24 of 40 profiles). For profiles achieving consensus, most were classified as clinical ILD (92%), low risk (54%) and stable (71%). Severity and disease progression overlapped in terms of framework items that were most influential in classifying patients (forced vital capacity, extent of lung involvement on high resolution chest CT [HRCT]); risk of progression was influenced primarily by disease duration.

CONCLUSIONS

Using our proposed conceptual framework, international experts were able to achieve a consensus on classifying SSc-ILD patients along the dimensions of disease severity, risk of progression and progression over time. Experts rely on similar items when classifying disease severity and progression: a combination of spirometry and gas exchange and quantitative HRCT.

Sex-dependent variation in cartilage adaptation: from degeneration to regeneration

Despite acknowledgement in the scientific community of sex-based differences in cartilage biology, the implications for study design remain unclear, with many studies continuing to arbitrarily assign demographics. Clinically, it has been well-established that males and females differ in cartilage degeneration, and accumulating evidence points to the importance of sex differences in the field of cartilage repair. However, a comprehensive review of the mechanisms behind this trend and the influence of sex on cartilage regeneration has not yet been presented. This paper aims to summarize current findings regarding sex-dependent variation in knee anatomy, sex hormones' effect on cartilage, and cartilaginous degeneration and regeneration, with a focus on stem cell therapies. Findings suggest that the stem cells themselves, as well as their surrounding microenvironment, contribute to sex-based differences. Accordingly, this paper underscores the contribution of both stem cell donor and recipient sex to sex-related differences in treatment efficacy. Cartilage regeneration is a field that needs more research to optimize strategies for better clinical results; taking sex into account could be a big factor in developing more effective and personalized treatments. The compilation of this information emphasizes the importance of investing further research in sex differences in cartilage biology.

A data-driven approach finds RNA polymerase III antibody and tendon friction rubs as enrichment tools for early diffuse scleroderma trials

OBJECTIVE

Clinical trials in early diffuse SSc have consistently shown a placebo group response with a declining modified Rodnan skin score (mRSS), with negative outcomes. Our objective was to identify strategies using clinical characteristics or laboratory values to improve trial design.

METHODS

We identified early diffuse SSc patients first seen at the University of Pittsburgh from 1980-2015. Eligible patients had ≥3 visits, with at least two mRSS scores within the first year of follow-up. We performed Kaplan-Meier analyses, group-based trajectory analysis of mRSS scores, followed by multivariable regression analysis and classification tree analysis. We applied the results to the abatacept in early diffuse systemic sclerosis (ASSET) trial outcome data.

RESULTS

We identified 403 patients with <18 months, and 514 with <36 months disease duration. The median number of mRSS follow-up scores was 14 (interquartile range 8, 25). All methodologic approaches identified skin thickness progression rate, RNA polymerase III (RNAP3) antibody positivity and presence of tendon friction rubs (TFR) as predictors of mRSS trajectory over 5 years of follow-up, and thereby as potential enrichment variables. When applied to the ASSET data, adjustment for both RNAP3 and TFR demonstrated reduction of the placebo mRSS response, particularly at 6 months. A significant difference in the ACR Composite Response Index in Systemic Sclerosis (CRISS) score was found with adjustment by RNAP3 at 6 months, and TFR or RNAP3 at 12 months.

CONCLUSION

Adjustment for both RNAP3 and TFR predicts mRSS trajectory and diminished the mRSS decline in ASSET placebo group, and identified significant differences in CRISS. RNAP3, particularly, is a stratification or enrichment approach to improve early diffuse SSc trial design.

Risk of relapse of ANCA-associated vasculitis among patients homozygous for the proteinase 3 gene Val119Ile polymorphism

BACKGROUND

The frequency of proteinase 3 gene (PRTN3) polymorphisms in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is not fully characterised. We hypothesise that the presence of a PRTN3 gene polymorphism (single nucleotide polymorphism (SNP) rs351111) is relevant for clinical outcomes.

METHODS

DNA variant calling for SNP rs351111 (chr.19:844020, c.355G>A) in PRTN3 gene assessed the allelic frequency in patients with PR3-AAV included in the Rituximab in ANCA-Associated Vasculitis trial. This was followed by RNA-seq variant calling to characterise the mRNA expression. We compared clinical outcomes between patients homozygous for PRTN3-Ile119 or PRTN3-Val119.

RESULTS

Whole blood samples for DNA calling were available in 188 patients. 75 patients with PR3-AAV had the allelic variant: 62 heterozygous PRTN3-Val119Ile and 13 homozygous for PRTN3-Ile119. RNA-seq was available for 89 patients and mRNA corresponding to the allelic variant was found in 32 patients with PR3-AAV: 25 heterozygous PRTN3-Val119Ile and 7 homozygous for PRTN3-Ile119. The agreement between the DNA calling results and mRNA expression of the 86 patients analysed by both methods was 100%. We compared the clinical outcomes of 64 patients with PR3-AAV: 51 homozygous for PRTN3-Val119 and 13 homozygous for PRTN3-Ile119. The frequency of severe flares at 18 months in homozygous PRTN3-Ile119 was significantly higher when compared with homozygous PRTN3-Val119 (46.2% vs 19.6%, p=0.048). Multivariate analysis identified homozygous PR3-Ile119 as main predictor of severe relapse (HR 4.67, 95% CI 1.16 to 18.86, p=0.030).

CONCLUSION

In patients with PR3-AAV, homozygosity for PRTN3-Val119Ile polymorphism appears associated with higher frequency of severe relapse. Further studies are necessary to better understand the association of this observation with the risk of severe relapse.

Spectrum of Clinical Presentations, Imaging Findings, and HLA Types in Immune Checkpoint Inhibitor-Induced Hypophysitis

Context

Hypophysitis is a known immune-related adverse event (irAE) of immune checkpoint inhibitors (CPIs), commonly associated with CTLA-4 inhibitors and less often with PD-1/PD-L1 inhibitors.

Objective

We aimed to determine clinical, imaging, and HLA characteristics of CPI-induced hypophysitis (CPI-hypophysitis).

Methods

We examined the clinical and biochemical characteristics, magnetic resonance imaging (MRI) of the pituitary, and association with HLA type in patients with CPI-hypophysitis.

Results

Forty-nine patients were identified. Mean age was 61.3 years, 61.2% were men, 81.6% were Caucasian, 38.8% had melanoma, and 44.5% received PD-1/PD-L1 inhibitor monotherapy while the remainder received CTLA-4 inhibitor monotherapy or CTLA-4/PD-1 inhibitor combination therapy. A comparison of CTLA-4 inhibitor exposure vs PD-1/PD-L1 inhibitor monotherapy revealed faster time to CPI-hypophysitis (median 84 vs 185 days, P < .01) and abnormal pituitary appearance on MRI (odds ratio 7.00, P = .03). We observed effect modification by sex in the association between CPI type and time to CPI-hypophysitis. In particular, anti-CTLA-4 exposed men had a shorter time to onset than women. MRI changes of the pituitary were most common at the time of hypophysitis diagnosis (55.6% enlarged, 37.0% normal, 7.4% empty or partially empty) but persisted in follow-up (23.8% enlarged, 57.1% normal, 19.1% empty or partially empty). HLA typing was done on 55 subjects; HLA type DQ0602 was over-represented in CPI-hypophysitis relative to the Caucasian American population (39.4% vs 21.5%, P = 0.01) and CPI population.

Conclusion

The association of CPI-hypophysitis with HLA DQ0602 suggests a genetic risk for its development. The clinical phenotype of hypophysitis appears heterogenous, with differences in timing of onset, changes in thyroid function tests, MRI changes, and possibly sex related to CPI type. These factors may play an important role in our mechanistic understanding of CPI-hypophysitis.

Differences in symptom experience among patients with systemic sclerosis: a cluster analytic approach to identifying subgroups

OBJECTIVES

Symptoms of people who have SSc are heterogeneous and difficult to address clinically. Because diverse symptoms often co-occur and may share common underlying mechanisms, identifying symptoms that cluster together may better target treatment approaches. We sought to identify and characterize patient subgroups based on symptom experience.

METHODS

An exploratory hierarchical agglomerative cluster analysis was conducted to identify subgroups from a large SSc cohort from a single US academic medical centre. Patient-reported symptoms of pain interference, fatigue, sleep disturbance, dyspnoea, depression and anxiety were used for clustering. A multivariate analysis of variance (MANOVA) was used to examine the relative contribution of each variable across subgroups. Analyses of variance were performed to determine participant characteristics based on subgroup assignment. Presence of symptom clusters were tallied within subgroup.

RESULTS

Participants (n = 587; 84% female, 41% diffuse cutaneous subtype, 59% early disease) divided into three subgroups via cluster analysis based on symptom severity: (i) no/minimal, (ii) mild, and (iii) moderate. Participants in mild and moderate symptoms subgroups had similar disease severity, but different symptom presentation. In the mild symptoms subgroup, pain, fatigue and sleep disturbance was the main symptom cluster. Participants in the moderate symptoms subgroup were characterized by co-occurring pain, fatigue, sleep disturbance, depression and anxiety.

CONCLUSION

Identification of distinct symptom clusters, particularly among SSc patients who experience mild and moderate symptoms, suggests potential differences in treatment approach and in mechanisms underlying symptom experience that require further study.

Risks of mortality and severe coronavirus disease 19 (COVID-19) outcomes in patients with or without systemic lupus erythematosus

OBJECTIVES

We compared the outcomes of patients with or without systemic lupus erythematosus (SLE) who were diagnosed with coronavirus disease 19 (COVID-19) and evaluated factors within patients with SLE associated with severe outcomes.

METHODS

This retrospective cohort study used the deidentified Optum COVID-19 electronic health record dataset to identify patients with COVID-19 from 1/1/2020 to 31/12/2020. Cases with SLE were matched with general controls at a ratio of 1:10 by age, sex, race and ethnicity and COVID-19 diagnosis date. Outcomes included 30-day mortality, mechanical ventilation, hospitalisation and intensive care unit admission. We evaluated the relationship between COVID-19-related outcomes and SLE using multivariable logistic regression. In addition, within SLE cases, we examined factors associated with COVID-19 related outcomes, including disease activity and SLE therapy.

RESULTS

We included 687 patients matched with 6870 controls. Unadjusted rates of outcomes for patients with SLE were significantly worse than for matched controls including mortality (3.6% vs 1.8%), mechanical ventilation (6% vs 2.5%) and hospitalisation (31% vs 17.7%) (all p<0.001). After multivariable adjustment, patients with SLE had increased risks of mechanical ventilation (OR 1.81, 95% CI 1.16 to 2.82) and hospitalisation (OR 1.32, 95% CI 1.05 to 1.65). Among patients with SLE, severe disease activity was associated with increased risks of mechanical ventilation (OR 5.83, 95% CI 2.60 to 13.07) and hospitalisation (OR 3.97, 95% CI 2.37 to 6.65). Use of glucocorticoids, mycophenolate and tacrolimus before COVID-19 was associated with worse outcomes.

CONCLUSION

Patients with SLE had increased risk of severe COVID-19-related outcomes compared with matched controls. Patients with severe SLE disease activity or prior use of corticosteroids experienced worse outcomes.

Advances in Skin Tissue Engineering and Regenerative Medicine

There are an estimated 500,000 patients treated with full-thickness wounds in the United States every year. Fire-related burn injuries are among the most common and devastating types of wounds that require advanced clinical treatment. Autologous split-thickness skin grafting is the clinical gold standard for the treatment of large burn wounds. However, skin grafting has several limitations, particularly in large burn wounds, where there may be a limited area of non-wounded skin to use for grafting. Non-cellular dermal substitutes have been developed but have their own challenges; they are expensive to produce, may require immunosuppression depending on design and allogenic cell inclusion. There is a need for more advanced treatments for devastating burns and wounds. This manuscript provides a brief overview of some recent advances in wound care, including the use of advanced biomaterials, cell-based therapies for wound healing, biological skin substitutes, biological scaffolds, spray on skin and skin bioprinting. Finally, we provide insight into the future of wound care and technological areas that need to be addressed to support the development and incorporation of these technologies.

Approach to Hypophosphatemic Rickets

Hypophosphatemic rickets typically presents in infancy or early childhood with skeletal deformities and growth plate abnormalities. The most common causes are genetic (such as X-linked hypophosphatemia), and these typically will result in lifelong hypophosphatemia and osteomalacia. Knowledge of phosphate metabolism, including the effects of fibroblast growth factor 23 (FGF23) (an osteocyte produced hormone that downregulates renal phosphate reabsorption and 1,25-dihydroxyvitamin-D (1,25(OH)2D) production), is critical to determining the underlying genetic or acquired causes of hypophosphatemia and to facilitate appropriate treatment. Serum phosphorus should be measured in any child or adult with musculoskeletal complaints suggesting rickets or osteomalacia. Clinical evaluation incudes thorough history, physical examination, laboratory investigations, genetic analysis (especially in the absence of a guiding family history), and imaging to establish etiology and to monitor severity and treatment course. The treatment depends on the underlying cause, but often includes active forms of vitamin D combined with phosphate salts, or anti-FGF23 antibody treatment (burosumab) for X-linked hypophosphatemia. The purpose of this article is to explore the approach to evaluating hypophosphatemic rickets and its treatment options.

Gastroparesis in systemic sclerosis: a detailed analysis using whole-gut scintigraphy

OBJECTIVES

Gastroparesis is a common complication of SSc. We sought to determine the degree of overlap between gastroparesis and dysmotility in other areas of the gut, correlate our findings with gastrointestinal (GI) symptoms, and examine associations between gastroparesis and SSc features.

METHODS

Whole-gut scintigraphy was performed on SSc patients who were enrolled in the Johns Hopkins Scleroderma Cohort, for whom detailed longitudinal clinical and serologic data are collected. A subset of patients completed the University of California Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract Instrument 2.0 (UCLA GIT 2.0) to quantify their GI symptoms. We examined associations between the presence and severity of gastroparesis, GI symptoms, and SSc clinical features.

RESULTS

Ninety-seven SSc patients with and without GI symptoms underwent whole-gut scintigraphy and completed the gastric emptying study. Of the 97, 34 (35%) met criteria for gastroparesis. Of the measures assessed, delayed liquid emptying captured more patients with delayed gastric transit than delayed solid emptying (74% vs 55%), and percentage liquid emptying correlated best with GIT Reflux (ρ = -0.33, P = 0.01) and Distension (ρ = -0.30, P = 0.03) scores. Of 33 patients with gastroparesis, 30 (91%) had abnormal transit in other areas of the GI tract. Higher anti-centromere protein B (CENP-B) titres correlated with slower gastric emptying (ρ = -0.26, P = 0.03), but no specific clinical features of SSc were associated with gastroparesis.

CONCLUSIONS

Gastric emptying of liquids when given alongside solids may be more sensitive and provide a more clinically relevant measure of gastroparesis in SSc than solid gastric emptying or liquid gastric emptying alone. SSc patients with gastroparesis frequently have dysmotility in other areas of the GI tract, underscoring the need for whole-gut scintigraphy to evaluate the entire gut.

Sourcing cells for in vitro models of human vascular barriers of inflammation

The vascular system plays a critical role in the progression and resolution of inflammation. The contributions of the vascular endothelium to these processes, however, vary with tissue and disease state. Recently, tissue chip models have emerged as promising tools to understand human disease and for the development of personalized medicine approaches. Inclusion of a vascular component within these platforms is critical for properly evaluating most diseases, but many models to date use "generic" endothelial cells, which can preclude the identification of biomedically meaningful pathways and mechanisms. As the knowledge of vascular heterogeneity and immune cell trafficking throughout the body advances, tissue chip models should also advance to incorporate tissue-specific cells where possible. Here, we discuss the known heterogeneity of leukocyte trafficking in vascular beds of some commonly modeled tissues. We comment on the availability of different tissue-specific cell sources for endothelial cells and pericytes, with a focus on stem cell sources for the full realization of personalized medicine. We discuss sources available for the immune cells needed to model inflammatory processes and the findings of tissue chip models that have used the cells to studying transmigration.

The Effects of Combined Respiratory-Gated Auricular Vagal Afferent Nerve Stimulation and Mindfulness Meditation for Chronic Low Back Pain: A Pilot Study

OBJECTIVE

Respiratory-gated Auricular Vagal Afferent Nerve stimulation (RAVANS) is a safe nonpharmacological approach to managing chronic pain. The purpose of the current study was to examine (1) the feasibility and acceptability of RAVANS, combined with mindful meditation (MM) for chronic low back pain (CLBP), (2) the potential synergy of MM+RAVANS on improving pain, and (3) possible moderators of the influence of MM+RAVANS on pain.

DESIGN

Pilot feasibility and acceptability study.

SETTING

Pain management center at large academic medical center.

SUBJECTS

Nineteen adults with CLBP and previous MM training.

METHODS

Participants attended two sessions during which they completed quantitative sensory testing (QST), rated pain severity, and completed a MM+stimulation session. Participants received RAVANS during one visit and sham stimulation during the other, randomized in order. Following intervention, participants repeated QST.

RESULTS

MM+RAVANS was well tolerated, acceptable, and feasible to provide relief for CLBP. Both MM+stimulation sessions resulted in improved back pain severity, punctate pain ratings, and pressure pain threshold. Individuals with greater negative affect showed greater back pain improvement from MM+RAVANS while those with greater mindfulness showed greater back pain improvement from MM+sham.

CONCLUSIONS

Results suggest that for CLBP patients with prior MM training, the analgesic effects of MM may have overshadowed effects of RAVANS given the brief single session MM+RAVANS intervention. However, those with greater negative affect may benefit from combined MM+RAVANS.

Medullary kappa-opioid receptor neurons inhibit pain and itch through a descending circuit

In perilous and stressful situations, the ability to suppress pain can be critical for survival. The rostral ventromedial medulla contains neurons that robustly inhibit nocioception at the level of the spinal cord through a top-down modulatory pathway. Although much is known about the role of the rostral ventromedial medulla in the inhibition of pain, the precise ability to directly manipulate pain-inhibitory neurons in the rostral ventromedial medulla has never been achieved. We now expose a cellular circuit that inhibits nocioception and itch in mice. Through a combination of molecular, tracing and behavioural approaches, we found that rostral ventromedial medulla neurons containing the kappa-opioid receptor inhibit itch and nocioception. With chemogenetic inhibition, we uncovered that these neurons are required for stress-induced analgesia. Using intersectional chemogenetic and pharmacological approaches, we determined that rostral ventromedial medulla kappa-opioid receptor neurons inhibit nocioception and itch through a descending circuit. Lastly, we identified a dynorphinergic pathway arising from the periaqueductal grey that modulates nociception within the rostral ventromedial medulla. These discoveries highlight a distinct population of rostral ventromedial medulla neurons capable of broadly and robustly inhibiting itch and nocioception.

OUP accepted manuscript

Metabolism regulates neuronal activity and modulates the occurrence of epileptic seizures. Here, using two rodent models of absence epilepsy, we show that hypoglycaemia increases the occurrence of spike-wave seizures. We then show that selectively disrupting glycolysis in the thalamus, a structure implicated in absence epilepsy, is sufficient to increase spike-wave seizures. We propose that activation of thalamic AMP-activated protein kinase, a sensor of cellular energetic stress and potentiator of metabotropic GABA_B-receptor function, is a significant driver of hypoglycaemia-induced spike-wave seizures. We show that AMP-activated protein kinase augments postsynaptic GABA_B-receptor-mediated currents in thalamocortical neurons and strengthens epileptiform network activity evoked in thalamic brain slices. Selective thalamic AMP-activated protein kinase activation also increases spike-wave seizures. Finally, systemic administration of metformin, an AMP-activated protein kinase agonist and common diabetes treatment, profoundly increased spike-wave seizures. These results advance the decades-old observation that glucose metabolism regulates thalamocortical circuit excitability by demonstrating that AMP-activated protein kinase and GABA_B-receptor cooperativity is sufficient to provoke spike-wave seizures.

Reducing Skin Toxicities from EGFR Inhibitors with Topical BRAF Inhibitor Therapy

Treatment of cancer with EGFR inhibitors is limited by on-target skin toxicities induced by inhibition of the MAPK pathway. BRAF inhibitors are known to paradoxically activate the MAPK downstream of EGFR, which we confirmed using human skin keratinocytes. We then conducted a phase I clinical trial testing the hypothesis that topical therapy with the BRAF inhibitor LUT014 could improve skin toxicities induced by EGFR inhibitors. Ten patients with metastatic colorectal cancer who had developed acneiform rash while being treated with cetuximab or panitumumab were enrolled in three cohorts. LUT014 was well tolerated, and there were no dose-limiting toxicities. The acneiform rash improved in the 6 patients who started with grade 2 rash in the low and intermediate cohorts. We conclude that topical LUT014 is safe and efficacious in improving rash from EGFR inhibitors, consistent with the mechanism of action inducting paradoxical MAPK activation. SIGNIFICANCE: BRAF inhibitor topical therapy could avoid dose reductions of EGFR inhibitors, locally treating the main dose-limiting skin toxicity of this class of agents.This article is highlighted in the In This Issue feature, p. 2113.

A comparison of physical function instruments in psoriatic arthritis: HAQ-DI vs MDHAQ vs PROMIS10 global physical health

OBJECTIVES

Physical function is a core outcome in PsA. We examined the construct validity and responsiveness of three commonly used instruments to assess physical function in PsA: HAQ disability index (HAQ-DI), MultiDimensional HAQ (MDHAQ) and the Patient-Reported Outcomes Measurement Information System (PROMIS®) Global-10.

METHODS

Between 2016 and 2019, patients with PsA were enrolled in the Psoriatic Arthritis Research Consortium longitudinal cohort study in the USA. Correlations were calculated at baseline and among change scores using Spearman's correlation coefficient. Standardized response means were calculated. Agreement with the 20% improvement cut-off was used to determine the potential effect of using MDHAQ or the PROMIS Global-10 physical health (GPH) subscore in place of HAQ-DI when assessing the ACR20.

RESULTS

A total of 274 patients were included in the analysis. The mean age of patients was 49 years and 51% were male. At baseline, the mean HAQ-DI was 0.6 (s.d. 0.6; range 0-3), the mean MDHAQ was 1.8 (s.d. 1.6; range 0-10) and the mean GPH T-score was 43.4 (s.d. 9.3; range 0-100). All three instruments were strongly correlated at baseline (rho 0.75-0.85). Change scores were moderately correlated (rho 0.42-0.71). Among therapy initiators, the mean change between two visits in HAQ-DI, MDHAQ and GPH was -0.1 (s.d. 0.4), -0.2 (s.d. 1.2) and 2.5 (s.d. 6.1), respectively. The standardized response means were 0.18, 0.16 and 0.41, respectively.

CONCLUSION

The three instruments tested are not directly interchangeable but have overall similar levels of responsiveness.

Def6 regulates endogenous type-I interferon responses in osteoblasts and suppresses osteogenesis

Bone remodeling involves a balance between bone resorption and formation. The mechanisms underlying bone remodeling are not well understood. DEF6 is recently identified as a novel loci associated with bone mineral density. However, it is unclear how Def6 impacts bone remodeling. We identify Def6 as a novel osteoblastic regulator that suppresses osteoblastogenesis and bone formation. Def6 deficiency enhances both bone resorption and osteogenesis. The enhanced bone resorption in Def6-/- mice dominates, leading to osteoporosis. Mechanistically, Def6 inhibits the differentiation of both osteoclasts and osteoblasts via a common mechanism through endogenous type-I IFN-mediated feedback inhibition. RNAseq analysis shows expression of a group of IFN stimulated genes (ISGs) during osteoblastogenesis. Furthermore, we found that Def6 is a key upstream regulator of IFNβ and ISG expression in osteoblasts. Collectively, our results identify a novel immunoregulatory function of Def6 in bone remodeling, and shed insights into the interaction between immune system and bone.

Extra-Large Gα Protein (XLαs) Deficiency Causes Severe Adenine-Induced Renal Injury with Massive FGF23 Elevation

Fibroblast growth factor-23 (FGF23) is critical for phosphate and vitamin D homeostasis. Cellular and molecular mechanisms underlying FGF23 production remain poorly defined. The extra-large Gα subunit (XLαs) is a variant of the stimulatory G protein alpha-subunit (Gsα), which mediates the stimulatory action of parathyroid hormone in skeletal FGF23 production. XLαs ablation causes diminished FGF23 levels in early postnatal mice. Herein we found that plasma FGF23 levels were comparable in adult XLαs knockout (XLKO) and wild-type littermates. Upon adenine-rich diet-induced renal injury, a model of chronic kidney disease, both mice showed increased levels of plasma FGF23. Unexpectedly, XLKO mice had markedly higher FGF23 levels than WT mice, with higher blood urea nitrogen and more severe tubulopathy. FGF23 mRNA levels increased substantially in bone and bone marrow in both genotypes; however, the levels in bone were markedly higher than in bone marrow. In XLKO mice, a positive linear correlation was observed between plasma FGF23 and bone, but not bone marrow, FGF23 mRNA levels, suggesting that bone, rather than bone marrow, is an important contributor to severely elevated FGF23 levels in this model. Upon folic acid injection, a model of acute kidney injury, XLKO and WT mice exhibited similar degrees of tubulopathy; however, plasma phosphate and FGF23 elevations were modestly blunted in XLKO males, but not in females, compared to WT counterparts. Our findings suggest that XLαs ablation does not substantially alter FGF23 production in adult mice but increases susceptibility to adenine-induced kidney injury, causing severe FGF23 elevations in plasma and bone.

Gut Microbiota in Human Systemic Lupus Erythematosus and a Mouse Model of Lupus

Gut microbiota dysbiosis has been observed in a number of autoimmune diseases. However, the role of the gut microbiota in systemic lupus erythematosus (SLE), a prototypical autoimmune disease characterized by persistent inflammation in multiple organs of the body, remains elusive. Here we report the dynamics of the gut microbiota in a murine lupus model, NZB/W F1, as well as intestinal dysbiosis in a small group of SLE patients with active disease. The composition of the gut microbiota changed markedly before and after the onset of lupus disease in NZB/W F1 mice, with greater diversity and increased representation of several bacterial species as lupus progressed from the predisease stage to the diseased stage. However, we did not control for age and the cage effect. Using dexamethasone as an intervention to treat SLE-like signs, we also found that a greater abundance of a group of lactobacilli (for which a species assignment could not be made) in the gut microbiota might be correlated with more severe disease in NZB/W F1 mice. Results of the human study suggest that, compared to control subjects without immune-mediated diseases, SLE patients with active lupus disease possessed an altered gut microbiota that differed in several particular bacterial species (within the genera Odoribacter and Blautia and an unnamed genus in the family Rikenellaceae) and was less diverse, with increased representation of Gram-negative bacteria. The Firmicutes/Bacteroidetes ratios did not differ between the SLE microbiota and the non-SLE microbiota in our human cohort.IMPORTANCE SLE is a complex autoimmune disease with no known cure. Dysbiosis of the gut microbiota has been reported for both mice and humans with SLE. In this emerging field, however, more studies are required to delineate the roles of the gut microbiota in different lupus-prone mouse models and people with diverse manifestations of SLE. Here, we report changes in the gut microbiota in NZB/W F1 lupus-prone mice and a group of SLE patients with active disease.