CanVasc consensus recommendations for the use of avacopan in antineutrophil cytoplasm antibody-associated vasculitis: 2022 addendum.

OBJECTIVE: In 2020, the Canadian Vasculitis Research Network (CanVasc) published their updated recommendations for the management of ANCA-associated vasculitides (AAV). The current addendum provides further recommendations regarding the use of avacopan in AAV based on a review of newly available evidence. METHODS: An updated systematic literature review on avacopan (formerly, CCX168) using Medline, Embase, and the Cochrane Library was performed for publications up to September 2022. New recommendations were developed and categorized according to the EULAR grading levels, as done for previous CanVasc recommendations. A modified Delphi procedure and videoconferences were used to reach ≥80% consensus on the inclusion, wording and grading of each recommendation. RESULTS: Three new recommendations were developed. They focus on avacopan therapy indication and duration, as well as timely glucocorticoid tapering. CONCLUSION: These 2022 addended recommendations provide rheumatologists, nephrologists and other specialists caring for patients with AAV with guidance for the use of avacopan, based on current evidence and consensus from Canadian experts.

Complement-Amplifying Conditions in Atypical Hemolytic Uremic Syndrome: A Canadian Case Series.

Rationale: Thrombotic microangiopathies (TMAs) are systemic disorders that often affect the kidneys and encompass a heterogeneous group of conditions, including atypical hemolytic uremic syndrome (aHUS). The complement pathway is thought to play a crucial role in the pathogenesis of aHUS, and a favorable response can be obtained through complement C5 inhibition. There is emerging evidence to suggest that the same is also true for several other forms of TMA. Objective: The purpose of this series is to report cases of aHUS in which both an innate defect of the alternative complement pathway and a complement-amplifying condition were suspected. Methods: This case series describes 8 patients who were managed in Canadian tertiary centers for aHUS and who presented initially with complement-amplifying conditions. Results: In all cases, aHUS was associated with organ dysfunction and in some, with an innate defect of the alternative complement pathway. The complement-amplifying conditions identified were diverse including immune disorders, pregnancy, and a Shiga toxin infection. Patients improved rapidly when treated with eculizumab or plasma exchange. Conclusions: These observations illustrate the seriousness of secondary aHUS. They also add to existing lines of evidence that the complement pathway is potentially involved in this condition and that it should be considered as a therapeutic target of interest under such circumstances.

Justification: Les microangiopathies thrombotiques (MAT) sont des troubles systémiques qui affectent souvent les reins et qui englobent un groupe hétérogène d'affections, notamment le syndrome hémolytique et urémique atypique (SHUa). On pense que la voie du complément joue un rôle crucial dans la pathogenèse du SHUa et qu'une réponse favorable pourrait être obtenue par inhibition du complément C5. De nouvelles preuves suggèrent qu'il en serait de même pour plusieurs autres formes de MAT. Objectif: Cette série vise à rapporter des cas de SHUa pour lesquels on soupçonnait à la fois une anomalie congénitale de la voie alterne du complément et une condition d'amplification du complément. Méthodologie: Cette série décrit les cas de huit patients qui présentaient initialement des conditions d'amplification du complément et qui ont été pris en charge pour un SHUa dans des centres tertiaires canadiens. Résultats: Dans tous les cas, le SHUa était associé à un dysfonctionnement d'organe et, dans certains cas, à une anomalie congénitale de la voie alterne du complément. Les conditions d'amplification du complément identifiées étaient diverses, notamment des troubles immunitaires, une grossesse et une infection à une shigatoxine. L'état des patients s'est rapidement amélioré après un traitement avec éculizumab ou des échanges plasmatiques. Conclusion: Ces observations illustrent la gravité du SHUa secondaire. Elles s'ajoutent aux preuves existantes qui suggèrent que la voie du complément est potentiellement impliquée dans cette pathologie et qu'elle devrait être considérée comme une cible thérapeutique d'intérêt dans de telles circonstances.

Making the Correct Diagnosis in Thrombotic Microangiopathy: A Narrative Review.

PURPOSE OF REVIEW: Thrombotic microangiopathy (TMA) is suspected in patients presenting with thrombocytopenia and evidence of a microangiopathic hemolytic anemia. Patients with TMA can be critically ill, so rapid and accurate identification of the underlying etiology is essential. Due to better insights into pathophysiology and causes of TMA, we can now categorize TMAs as thrombotic thrombocytopenic purpura, postinfectious (mainly Shiga toxin-producing Escherichia coli-induced) hemolytic uremic syndrome (HUS), TMA associated with a coexisting condition, or atypical HUS (aHUS). We recognized an unmet need in the medical community to guide the timely and accurate identification of TMA, the selection of tests to clarify its etiology, and the sequence of steps to initiate treatment. SOURCES OF INFORMATION: Key published studies relevant to the identification, classification, and treatment of TMAs in children or adults. These studies were obtained through literature searches conducted with PubMed or based on the prior knowledge of the authors. METHODS: This review is the result of a consultation process that reflects the consensus of experts from Canada, the United States, and the United Arab Emirates. The members represent individuals who are clinicians, researchers, and teachers in pediatric and adult medicine from the fields of hematology, nephrology, and laboratory medicine. Authors, through an iterative review process identified and synthesized information from relevant published studies. KEY FINDINGS: Thrombotic thrombocytopenic purpura occurs in the setting of insufficient activity of the von Willebrand factor protease known as ADAMTS13. Shiga toxin-producing Escherichia coli-induced hemolytic uremic syndrome, also known as "typical" HUS, is caused by gastrointestinal infections with bacteria that produce Shiga toxin (initially called verocytotoxin). A variety of clinical conditions or drug exposures can trigger TMA. Finally, aHUS occurs in the setting of inherited or acquired abnormalities in the alternative complement pathway leading to dysregulated complement activation, often following a triggering event such as an infection. It is possible to break the process of etiological diagnosis of TMA into 2 distinct steps. The first covers the initial presentation and diagnostic workup, including the processes of identifying the presence of TMA, appropriate initial tests and referrals, and empiric treatments when appropriate. The second step involves confirming the etiological diagnosis and moving to definitive treatment. For many forms of TMA, the ultimate response to therapies and the outcome of the patient depends on the rapid and accurate identification of the presence of TMA and then a standardized approach to seeking the etiological diagnosis. We present a structured approach to identifying the presence of TMA and steps to identifying the etiology including standardized lab panels. We emphasize the importance of early consultation with appropriate specialists in hematology and nephrology, as well as identification of whether the patient requires plasma exchange. Clinicians should consider appropriate empiric therapies while following the steps we have recommended toward definitive etiologic diagnosis and management of the TMA. LIMITATIONS: The evidence base for our recommendations consists of small clinical studies, case reports, and case series. They are generally not controlled or randomized and do not lend themselves to a stricter guideline-based methodology or a Grading of Recommendations Assessment, Development and Evaluation (GRADE)-based approach.

JUSTIFICATION: La microangiopathie thrombotique (MAT) est suspectée chez les patients présentant une thrombocytopénie et la preuve d'une anémie hémolytique microangiopathique (AHMA). Les patients atteints de MAT peuvent être gravement malades, il est donc essentiel de déterminer rapidement et précisément l'étiologie sous-jacente. Grâce à une meilleure connaissance de la physiopathologie et des causes de la MAT, nous pouvons désormais classer les MAT par catégorie: purpura thrombocytopénique thrombotique (PTT), syndrome hémolytique urémique post-infectieux (SHU) principalement induit par STEC (Escherichia coli produisant la toxine Shiga), ou MAT associée à une affection coexistante ou à un SHU atypique (SHUa). Nous avons constaté un besoin dans la communauté médicale pour guider à la fois la détection rapide et précise de la MAT, la sélection des tests pour clarifier son étiologie et la séquence des étapes menant à l'initiation du traitement. SOURCES: Des recherches documentaires sur PubMed et les connaissances antérieures des auteurs ont permis de colliger les principales études publiées portant sur la détection, la classification et le traitement de la MAT chez les enfants ou les adultes. MÉTHODOLOGIE: Cet examen est le résultat d'un processus de consultation qui reflète le consensus des experts du Canada, des États-Unis et des Émirats arabes Unis. Les membres représentent des cliniciens, des chercheurs et des enseignants en médecine pédiatrique et adulte dans les domaines de l'hématologie, de la néphrologie et de la médecine de laboratoire. Les auteurs, par le biais d'un processus d'examen itératif, ont colligé et synthétisé l'information provenant des études publiées jugées pertinentes. PRINCIPAUX RÉSULTATS: Le PTT survient lors d'une activité insuffisante de la protéase du facteur Willebrand connue sous le nom d'ADAMTS13. Le SHU-STEC, aussi appelé SHU « typique ¼, est causé par des infections gastro-intestinales dues à des bactéries produisant la toxine Shiga (initialement appelée vérocytotoxine). Plusieurs états pathologiques ou expositions à des médicaments peuvent déclencher la MAT. Quant au SHU atypique (SHUa), il survient en présence d'anomalies héréditaires ou acquises de la voie du complément alternatif qui mènent à un dérèglement de l'activation du complément, souvent à la suite d'un événement déclencheur comme une infection. On peut diviser le processus de diagnostic étiologique de la MAT en deux étapes distinctes. La première couvre la présentation initiale et le diagnostic, y compris les processus de détection de la MAT, les tests initiaux et aiguillages appropriés, ainsi que les traitements empiriques si nécessaire. La deuxième étape consiste à confirmer le diagnostic étiologique et à procéder au traitement définitif. Pour de nombreuses formes de MAT, la réponse ultime aux traitements et le résultat du patient dépendent de la détection rapide et précise de la MAT et ensuite, d'une approche standardisée pour la recherche du diagnostic étiologique. Nous présentons une approche structurée pour détecter la présence de MAT ainsi qu'une démarche pour rechercher l'étiologie, y compris des tableaux de laboratoire normalisés. Nous soulignons l'importance d'une consultation précoce avec les spécialistes appropriés en hématologie et en néphrologie, et de la détermination d'un éventuel besoin d'échange de plasma (PLEX) pour le patient. Les cliniciens devraient envisager les traitements empiriques appropriés tout en suivant la démarche que nous recommandons pour le diagnostic étiologique définitif et la gestion de la MAT. LIMITES: La base factuelle de nos recommandations est constituée de petites études cliniques, de rapports de cas et de séries de cas. Ces études ne sont généralement pas contrôlées ou randomisées et ne se prêtent pas à une méthodologie plus stricte basée sur des lignes directrices ni à une approche fondée sur le GRADE (Grading of Recommendations Assessment, Development and Evaluation).

CanVasc Consensus Recommendations for the Management of Antineutrophil Cytoplasm Antibody-associated Vasculitis: 2020 Update.

OBJECTIVE: In 2015, the Canadian Vasculitis Research Network (CanVasc) created recommendations for the management of antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) in Canada. The current update aims to revise existing recommendations and create additional recommendations, as needed, based on a review of new available evidence. METHODS: A needs assessment survey of CanVasc members informed questions for an updated systematic literature review (publications spanning May 2014 to September 2019) using Medline, Embase, and Cochrane. New and revised recommendations were developed and categorized according to the level of evidence and strength of each recommendation. The CanVasc working group used a 2-step modified Delphi procedure to reach > 80% consensus on the inclusion, wording, and grading of each new and revised recommendation. RESULTS: Eleven new and 16 revised recommendations were created and 12 original (2015) recommendations were retained. New and revised recommendations are discussed in detail within this document. Five original recommendations were removed, of which 4 were incorporated into the explanatory text. The supplementary material for practical use was revised to reflect the updated recommendations. CONCLUSION: The 2020 updated recommendations provide rheumatologists, nephrologists, and other specialists caring for patients with AAV in Canada with new management guidance, based on current evidence and consensus from Canadian experts.

Updated Canadian Expert Consensus on Assessing Risk of Disease Progression and Pharmacological Management of Autosomal Dominant Polycystic Kidney Disease.

PURPOSE: The purpose of this article is to update the previously published consensus recommendations from March 2017 discussing the optimal management of adult patients with autosomal dominant polycystic kidney disease (ADPKD). This document focuses on recent developments in genetic testing, renal imaging, assessment of risk regarding disease progression, and pharmacological treatment options for ADPKD. SOURCES OF INFORMATION: Published literature was searched in PubMed, the Cochrane Library, and Google Scholar to identify the latest evidence related to the treatment and management of ADPKD. METHODS: All pertinent articles were reviewed by the authors to determine if a new recommendation was required, or if the previous recommendation needed updating. The consensus recommendations were developed by the authors based on discussion and review of the evidence. KEY FINDINGS: The genetics of ADPKD are becoming more complex with the identification of new and rarer genetic variants such as GANAB. Magnetic resonance imaging (MRI) and computed tomography (CT) continue to be the main imaging modalities used to evaluate ADPKD. Total kidney volume (TKV) continues to be the most validated and most used measure to assess disease progression. Since the publication of the previous consensus recommendations, the use of the Mayo Clinic Classification for prognostication purposes has been validated in patients with class 1 ADPKD. Recent evidence supports the benefits of a low-osmolar diet and dietary sodium restriction in patients with ADPKD. Evidence from the Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD (REPRISE) trial supports the use of ADH (antidiuretic hormone) receptor antagonism in patients with ADPKD 18 to 55 years of age with eGFR (estimated glomerular filtration rate) of 25 to 65 mL/min/1.73 m2 or 56 to 65 years of age with eGFR of 25 to 44 mL/min/1.73 m2 with historical evidence of a decline in eGFR >2.0 mL/min/1.73 m2/year. LIMITATIONS: Available literature was limited to English language publications and to publications indexed in PubMed, the Cochrane Library, and Google Scholar. IMPLICATIONS: Advances in the assessment of the risk of disease progression include the validation of the Mayo Clinic Classification for patients with class 1 ADPKD. Advances in the pharmacological management of ADPKD include the expansion of the use of ADH receptor antagonism in patients 18 to 55 years of age with eGFR of 25 to 65 mL/min/1.73 m2 or 56 to 65 years of age with eGFR of 25 to 44 mL/min/1.73 m2 with historical evidence of a decline in eGFR >2.0 mL/min/1.73 m2/year, as per the results of the REPRISE study.

MOTIF: L'objet de cet article est de faire une mise à jour des recommandations consensuelles publiées en mars 2017 traitant de la prise en charge des patients adultes atteints de la maladie polykystique autosomique dominante (MPAD). Ce document s'intéresse aux développements récents en matière de dépistage génétique, d'imagerie rénale, d'évaluation des risques de progression de la maladie et des options de traitement pharmacologique de la MPAD. SOURCES: Les plus récents développements liés à la prise en charge et au traitement de la MPAD ont été colligés à partir des articles publiés sur le sujet dans PubMed, la bibliothèque Cochrane et Google Scholar. MÉTHODOLOGIE: Les auteurs ont relu tous les articles pertinents pour déterminer si de nouvelles recommandations étaient requises ou si les recommandations ultérieures nécessitaient une mise à jour. Les recommandations consensuelles ont été élaborées par les auteurs à partir de la discussion et de la révision des données probantes. PRINCIPAUX RÉSULTATS: Les caractéristiques génétiques de la MPAD deviennent de plus en plus complexes avec l'identification de nouvelles et de plus rares variantes telles que GANAB. L'IRM et la tomodensitométrie demeurent les principales modalités d'imagerie utilisées pour le diagnostic et l'évaluation de la MPAD. Le volume rénal total (VRT) continue d'être la mesure la mieux validée et la plus employée pour évaluer la progression de la maladie. Depuis la publication des précédentes recommandations consensuelles, le recours à la classification de la Clinique Mayo a été validé à des fins pronostiques chez les patients atteints de MPAD de type 1. Des données récentes soutiennent les bienfaits d'une diète à faible osmolarité et des restrictions alimentaires pour le sodium chez les patients atteints de la MPAD. Les résultats de l'essai REPRISE (Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD) viennent appuyer le recours à des antagonistes des récepteurs de l'ADH chez les patients atteints de la MPAD âgés de 18 à 55 ans et dont le DFGe se situe entre 25 et 65 mL/min/1,73 m2 ou chez ceux qui sont âgés de 56 à 65 ans et dont le DFGe se situe entre 25 et 44 mL/min/1,73 m2 et dont les antécédents montrent un déclin du DFGe supérieur à 2,0 mL/min/1,73 m2 par année. LIMITES: La recherche s'est limitée aux publications en anglais et indexées sur PubMed, Google Scholar et dans la bibliothèque Cochrane. IMPLICATIONS: Les avancées dans l'évaluation du risque de progression de la maladie incluent la validation de la classification de la clinique Mayo pour les patients atteints de MPAD de type 1. Les développements dans la prise en charge pharmacologique de la MPAD incluent les résultats obtenus lors de l'essai REPRISE; soit l'élargissement de l'utilisation des antagonistes des récepteurs de l'ADH aux patients âgés de 18 à 25 ans dont le DFGe se situe entre 25 et 65 mL/min/1,73 m2 ou à ceux âgés de 56 à 65 ans dont le DFGe se situe entre 25 et 44 mL/min/1,73 m2 et dont les antécédents montrent un déclin du DFGe supérieur à 2,0 mL/min/1,73 m2 par année.

Assessing Risk of Disease Progression and Pharmacological Management of Autosomal Dominant Polycystic Kidney Disease: A Canadian Expert Consensus.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder worldwide. The disease is characterized by renal cysts and progressive renal failure due to progressive enlargement of cysts and renal fibrosis. An estimated 45% to 70% of patients with ADPKD progress to end-stage renal disease by age 65 years. Although both targeted and nontargeted therapies have been tested in patients with ADPKD, tolvaptan is currently the only pharmacological therapy approved in Canada for the treatment of ADPKD. The purpose of this consensus recommendation is to develop an evidence-informed recommendation for the optimal management of adult patients with ADPKD. This document focuses on the role of genetic testing, the role of renal imaging, predicting the risk of disease progression, and pharmacological treatment options for ADPKD. These areas of focus were derived from 2 national surveys that were disseminated to nephrologists and patients with ADPKD with the aim of identifying unmet needs in the management of ADPKD in Canada. Specific recommendations are provided for the treatment of ADPKD with tolvaptan.

La polykystose rénale autosomique dominante (PKRAD) est le trouble rénal héréditaire le plus fréquent dans le monde. La maladie est caractérisée par la présence de kystes rénaux et par une insuffisance rénale progressive provoquée par l'élargissement progressif des kystes et par une fibrose rénale. Environ 45 à 70% des patients atteints de PKRAD verront leur état évoluer vers l'insuffisance rénale terminale avant l'âge de 65 ans. Bien que les thérapies ciblées et non ciblées aient été testées chez des patients atteints de PKRAD, le tolvaptan est le seul médicament approuvé au Canada pour le traitement de la PKRAD. L'objectif de cette recommandation consensuelle est l'élaboration de recommandations fondées sur des données probantes pour une prise en charge optimale des patients adultes atteints de PKRAD. Ce document met l'accent sur le rôle du dépistage génétique et de l'imagerie rénale, sur les façons de prédire le risque de progression de la maladie et sur les options de traitement pharmacologique de la PKRAD. Ces domaines d'action dérivent de deux enquêtes nationales diffusées aux néphrologues et aux patients canadiens atteints de PKRAD, et qui avaient pour but d'identifier les besoins non satisfaits dans la prise en charge le la PKRAD au Canada. Des recommandations spécifiques sont fournies pour le traitement de la PKD avec le tolvaptan.

Complication rates after left- versus right-sided carotid endarterectomy.

BACKGROUND: Studies suggest that the side of carotid endarterectomy (CE) may influence the rate of postoperative complications. We sought to clarify this by (1) analysis of individual-level data from 3 large studies and (2) systematic review and meta-analysis of additional published descriptions of outcomes by side. METHODS AND RESULTS: The Western Canada Carotid Endarterectomy (WCCE) study (n=3164) was analyzed for outcomes by side along with data from the North American Symptomatic Carotid Endarterectomy Trial (NASCET; n=1415), and the ASA [Acetylsalicylic Acid] in Carotid Endarterectomy Trial (ACE; n=2469). Pooled analysis of individual-level data from these three studies allowed calculation of rate ratios for stroke or death by side. Medline and EMBASE were searched to identify additional studies reporting CE outcomes by side, and an overall risk ratio for outcomes by side was determined with fixed-effects meta-analysis. The WCCE in-hospital stroke or death rates for left and right-sided CE were 3.72% and 3.07%, respectively (P=0.27). A pooled analysis of the NASCET and ACE trials also revealed higher stroke or death rates for left-sided CE (5.39% versus 2.96%; P<0.001). The corresponding risk-adjusted rate ratios for stroke or death for left- versus right-sided surgery were 1.22 (95% CI, 0.83 to 1.77) for WCCE and 1.82 (1.32 to 2.50) for the pooled NASCET and ACE trials. Systematic review of the literature identified 2 additional studies. Meta-analysis of all 5 available studies yielded a corresponding pooled rate ratio for stroke or death of 1.36 (1.18 to 1.56). CONCLUSIONS: Left-sided CE is consistently associated with higher postoperative adverse event rates. Research into potential mechanisms is required to explain and address this finding.

PABPN1 overexpression leads to upregulation of genes encoding nuclear proteins that are sequestered in oculopharyngeal muscular dystrophy nuclear inclusions.

Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset disease caused by expanded (GCN)12-17 stretches encoding the N-terminal polyalanine domain of the poly(A) binding protein nuclear 1 (PABPN1). OPMD is characterized by intranuclear inclusions (INIs) in skeletal muscle fibers, which contain PABPN1, molecular chaperones, ubiquitin, proteasome subunits, and poly(A)-mRNA. We describe an adenoviral model of PABPN1 expression that produces INIs in most cells. Microarray analysis revealed that PABPN1 overexpression reproducibly changed the expression of 202 genes. Sixty percent of upregulated genes encode nuclear proteins, including many RNA and DNA binding proteins. Immunofluorescence microscopy revealed that all tested nuclear proteins encoded by eight upregulated genes colocalize with PABPN1 within the INIs: CUGBP1, SFRS3, FKBP1A, HMG2, HNRPA1, PRC1, S100P, and HSP70. In addition, CUGBP1, SFRS3, and FKBP1A were also found in OPMD muscle INIs. This study demonstrates that a large number of nuclear proteins are sequestered in OPMD INIs, which may compromise cellular function.

Polymorphism, shared functions and convergent evolution of genes with sequences coding for polyalanine domains.

Mutations causing expansions of polyalanine domains are responsible for nine hereditary diseases. Other GC-rich sequences coding for some polyalanine domains were found to be polymorphic in human. These observations prompted us to identify all sequences in the human genome coding for polyalanine stretches longer than four alanines and establish their degree of polymorphism. We identified 494 annotated human proteins containing 604 polyalanine domains. Thirty-two percent (31/98) of tested sequences coding for more than seven alanines were polymorphic. The length of the polyalanine-coding sequence and its GCG or GCC repeat content are the major predictors of polymorphism. GCG codons are over-represented in human polyalanine coding sequences. Our data suggest that GCG and GCC codons play a key role in polyalanine-coding sequence appearance and polymorphism. The grouping by shared function of polyalanine-containing proteins in Homo sapiens, Drosophila melanogaster and Caenorhabditis elegans shows that the majority are involved in transcriptional regulation. Phylogenetic analyses of HOX, GATA and EVX protein families demonstrate that polyalanine domains arose independently in different members of these families, suggesting that convergent molecular evolution may have played a role. Finally polyalanine domains in vertebrates are conserved between mammals and are rarer and shorter in Gallus gallus and Danio rerio. Together our results show that the polymorphic nature of sequences coding for polyalanine domains makes them prime candidates for mutations in hereditary diseases and suggests that they have appeared in many different protein families through convergent evolution.