Predictors of inflammatory arthritis among new rheumatology referrals: a cross-sectional study.

Objectives: Early diagnosis and treatment of inflammatory arthritis (IA) is essential to optimize disease control. We aimed to identify variables that distinguish IA from non-inflammatory arthropathy by performing a cross-sectional study of rheumatology referral letters and visit records. Further work describes time to assessment and documentation of variables within referral letters. Methods: We reviewed rheumatology referral letters and new patient visits over a 6-month period. The diagnosis of IA was based on the clinical judgement of the assessing rheumatologist. IA diagnoses included RA, SpAs, unspecified IA, PMR, crystalline arthropathies and remitting seronegative symmetrical synovitis with pitting oedema. Univariate analysis was performed for each variable. Multivariable logistic regression was performed on statistically significant variables. Results: Of 697 patients referred for arthralgia, 25.7% were diagnosed with IA. Variables predictive of IA included tenderness and swelling on examination and ≥1 h of morning stiffness. Increasing arthralgia duration, fatigue and brain fog were negative predictors. The median time from referral to IA diagnosis was 55 days and 20.7% of these patients were seen within 6 weeks. Among referral letters, documentation of arthralgia duration, morning stiffness or joint examination findings was uncommon (31%, 20.5% and 56.7%, respectively). Conclusion: We identified positive and negative predictors of IA. Referral letters often missed key information required for the triaging process. Future efforts will be directed towards build a triaging tool to improve the referral quality and capture of those patients with IA who need earlier access to rheumatology care.

Efficacy of Combination Therapy with the JAK Inhibitor Baricitinib in the Treatment of COVID-19.

Coronavirus disease-19 (COVID-19), resulting from infection with SARS-CoV-2, spans a wide spectrum of illness. In severely ill patients, highly elevated serum levels of certain cytokines and considerable cytolytic T cell infiltrates in the lungs have been observed. These same patients may bear low to negligible viral burdens suggesting that an overactive immune response, often termed cytokine storm, contributes to the severity of COVID-19. We report the safety and efficacy of baricitinib combined with remdesivir and dexamethasone in a retrospective review of 45 hospitalized patients with COVID-19 pneumonia at a tertiary academic medical center. Patients received 7-day course of baricitinib, 5-day course of remdesivir, and 10-day course of dexamethasone. Clinical status and biomarkers were obtained daily. Outcomes assessed include mortality, duration of hospitalization, presence of shock, need for supplemental oxygen, need for non-invasive ventilation, need for mechanical ventilation, and development of thrombosis. Obesity and multiple medical comorbidities were associated with hospitalization in the setting of COVID-19. Treated patients demonstrated rapid declines of C-reactive protein (CRP), ferritin and D-dimer with gradual improvement in hemoglobin, platelet counts, and clinical status. Only 2 of 45 (4.4%) treated patients required mechanical ventilation after initiating treatment, and there were six deaths (13.3%). Only 2 of 45 (4.4%) treated patients required mechanical ventilation after initiating treatment. There were six deaths (13.3%) and these were associated with lower BMI. These findings support the utility of immunosuppression via JAK inhibition in moderate to severe COVID-19 pneumonia. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42399-022-01121-4.

Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis with Kidney Involvement in a Patient with AL Amyloidosis.

Antineutrophil cytoplasmic autoantibody (ANCA) vasculitis has occasionally been associated with other systemic glomerulonephritis, such as anti-glomerular basement membrane disease. Here, we report the first clinical case of ANCA-associated crescentic glomerulonephritis with AL amyloidosis. An 81-years-old gentleman presented to the hospital with acute kidney injury (serum creatinine 4.7 mg/dL) on a background of chronic kidney disease and volume overload. Autoimmune serology was remarkable for p-ANCA and myeloperoxidase positivity. A renal biopsy confirmed pauci-immune glomerulonephritis and lambda light-chain amyloid deposition (confirmed on liquid chromatography and tandem mass spectrometry). The patient was initially managed with rituximab and subsequently transitioned to bortezomib-based chemotherapy but died due to decompensated heart failure. This case report promotes greater awareness of the unusual presentation of amyloidosis and guides future research and treatment.

Parathyroid hormone-related protein is induced by hypoxia and promotes expression of the differentiated phenotype of human articular chondrocytes.

PTHrP (parathyroid hormone-related protein) is crucial for normal cartilage development and long bone growth and acts to delay chondrocyte hypertrophy and terminal differentiation in the growth plate. After growth plate closure adult HACs (human articular chondrocytes) still produce PTHrP, suggesting a possible role for this factor in the permanent articular cartilage. However, the expression regulation and function of PTHrP in the permanent articular cartilage is unknown. Human articular cartilage is an avascular tissue and functions in a hypoxic environment. The resident chondrocytes have adapted to hypoxia and use it to drive their tissue-specific functions. In the present study, we explored directly in normal articular chondrocytes isolated from a range of human donors the effect of hypoxia on PTHrP expression and whether PTHrP can regulate the expression of the permanent articular chondrocyte phenotype. We show that in HACs PTHrP is up-regulated by hypoxia in a HIF (hypoxia-inducible factor)-1α and HIF-2α-dependent manner. Using recombinant PTHrP, siRNA-mediated depletion of endogenous PTHrP and by blocking signalling through its receptor [PTHR1 (PTHrP receptor 1)], we show that hypoxia-induced PTHrP is a positive regulator of the key cartilage transcription factor SOX9 [SRY (sex determining region on the Y chromosome)-box 9], leading to increased COL2A1 (collagen type II, α1) expression. Our findings thus identify PTHrP as a potential factor for cartilage repair therapies through its ability to promote the differentiated HAC phenotype.

Hypoxia promotes the production and inhibits the destruction of human articular cartilage.

OBJECTIVE: To determine the effects of hypoxia on both anabolic and catabolic pathways of metabolism in human articular cartilage and to elucidate the roles played by hypoxia-inducible factors (HIFs) in these responses. METHODS: Normal human articular cartilage from a range of donors was obtained at the time of above-the-knee amputations due to sarcomas not involving the joint space. Fresh cartilage tissue explants and isolated cells were subjected to hypoxia and treatment with interleukin-1α. Cell transfections were performed on isolated human chondrocytes. RESULTS: Using chromatin immunoprecipitation, we found that hypoxia induced cartilage production in human tissue explants through direct binding of HIF-2α to a specific site in the master-regulator gene SOX9. Importantly, hypoxia also suppressed spontaneous and induced destruction of human cartilage in explant culture. We found that anticatabolic responses were predominantly mediated by HIF-1α. Manipulation of the hypoxia-sensing pathway through depletion of HIF-targeting prolyl hydroxylase-containing protein 2 (PHD-2) further enhanced cartilage responses as compared to hypoxia alone. Hypoxic regulation of tissue-specific metabolism similar to that in human cartilage was observed in pig, but not mouse, cartilage. CONCLUSION: We found that resident chondrocytes in human cartilage are exquisitely adapted to hypoxia and use it to regulate tissue-specific metabolism. Our data revealed that while fundamental regulators, such as SOX9, are key molecules both in mice and humans, the way in which they are controlled can differ. This is all the more important since it is upstream regulators such as this that need to be directly targeted for therapeutic benefit. HIF-specific hydroxylase PHD-2 may represent a relevant target for cartilage repair.

Inhibition of hypoxia-inducible factor-targeting prolyl hydroxylase domain-containing protein 2 (PHD2) enhances matrix synthesis by human chondrocytes.

Human articular cartilage is an avascular tissue, and therefore it functions in a hypoxic environment. Cartilage cells, the chondrocytes, have adapted to this and actually use hypoxia to drive tissue-specific functions. We have previously shown that human chondrocytes enhance cartilage matrix synthesis in response to hypoxia specifically through hypoxia-inducible factor 2alpha (HIF-2alpha)-mediated up-regulation of master regulator transcription factor SOX9, which in turn drives expression of the main cartilage-specific extracellular matrix genes. HIF-alpha isoforms are themselves regulated by specific prolyl hydroxylase domain-containing proteins, which target them for proteosomal degradation. In fact, prolyl hydroxylase domains are the direct oxygen sensors because they require molecular oxygen as a co-substrate. Here, we have identified PHD2 as the dominant isoenzyme regulating HIF-2alpha stability in human chondrocytes. Moreover, specific inhibition of PHD2 using RNA interference-mediated depletion caused an up-regulation of SOX9 and enhanced extracellular matrix protein production. Depletion of PHD2 resulted in greater HIF-2alpha levels and therefore enhanced SOX9-induced cartilage matrix production compared with the levels normally found in hypoxia (1% oxygen) implying that PHD2 inhibition offers a novel means to enhance cartilage repair in vivo. The need for HIF-specific hydroxylase inhibition was highlighted because treatment with the 2-oxoglutarate analogue dimethyloxalylglycine (which also inhibits the collagen prolyl 4-hydroxylases) prevented secretion of type II collagen, a critical cartilage matrix component.

Hypoxia. HIF-mediated articular chondrocyte function: prospects for cartilage repair.

In a chronically hypoxic tissue such as cartilage, adaptations to hypoxia do not merely include cell survival responses, but also promotion of its specific function. This review will focus on describing such hypoxia-mediated chondrocyte function, in particular in the permanent articular cartilage. The molecular details of how chondrocytes sense and respond to hypoxia and how this promotes matrix synthesis have recently been examined, and specific manipulation of hypoxia-induced pathways is now considered to have potential therapeutic application to maintenance and repair of articular cartilage.