A new, deep learning-based method for the analysis of autopsy kidney samples used to study sex differences in glomerular density and size in a forensic population.

Artificial intelligence (AI) is increasingly used in forensic anthropology and genetics to identify the victim and the cause of death. The large autopsy samples from persons with traumatic causes of death but without comorbidities also offer possibilities to analyze normal histology with AI. We propose a new deep learning-based method to rapidly count glomerular number and measure glomerular density (GD) and volume in post-mortem kidney samples obtained in a forensic population. We assessed whether this new method detects glomerular differences between men and women without known kidney disease. Autopsies performed between 2009 and 2015 were analyzed if subjects were aged ≥ 18 years and had no known kidney disease, diabetes mellitus, or hypertension. A large biopsy was taken from each kidney, stained with hematoxylin and eosin, and scanned. An in-house developed deep learning-based algorithm counted the glomerular density (GD), number, and size. Out of 1165 forensic autopsies, 86 met all inclusion criteria (54 men). Mean (± SD) age was 43.5 ± 14.6; 786 ± 277 glomeruli were analyzed per individual. There was no significant difference in GD between men and women (2.18 ± 0.49 vs. 2.30 ± 0.57 glomeruli/mm2, p = 0.71); glomerular diameter, area, and volume also did not differ. GD correlated inversely with age, kidney weight, and glomerular area. Glomerular area and volume increased significantly with age. In this study, there were no sex differences in glomerular density or size. Considering the size of the kidney samples, the use of the presented deep learning method can help to analyze large renal autopsy biopsies and opens perspectives for the histological study of other organs.

[Anti-glomerular basement membrane disease]. / Maladie des anticorps anti-membrane basale glomérulaire.

Anti-glomerular basement membrane disease is a rare disease. In its classical presentation it associates rapidly progressive glomerulonephritis and diffuse alveolar hemorrhage, linked to the presence of antibodies targeting type IV collagen in the glomerular and alveolar basal membrane. Anti-GBM disease warrants prompt medical management to limit permanent kidney damage and mortality. Treatment includes plasma exchanges to quickly remove pathogenic antibodies and immunosuppressants to stop their production. This article reviews the pathogenesis and current treatments.

La maladie des anticorps anti-membrane basale glomérulaire (anti-MBG) est une entité rare. Dans sa présentation classique, elle associe une glomérulonéphrite rapidement progressive et une hémorragie alvéolaire diffuse liée à des anticorps dirigés contre le collagène de type IV des membranes basales glomérulaire et alvéolaire. Les pronostics rénal et vital sont engagés. Le traitement doit être prompt et comprend des plasmaphérèses visant à éliminer les anticorps pathogéniques ainsi qu'une immunosuppression destinée à supprimer leur production. Cet article passe en revue la pathogénie et les traitements actuels.

[Granulomatosis with polyangiitis: what's new?] / Granulomatose avec polyangéite : quoi de neuf ?

Within the group of antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides, granulomatosis with polyangiitis (GPA) is the most frequent. The incidence is around 10 to 20 cases/million/year. Clinical manifestations are varied, with ENT, lungs and kidneys most frequently involved. ANCA are pathogenic by triggering neutrophil activation, which leads to vascular damage. Detection of ANCA is most helpful in establishing the diagnosis, but serology may be negative in GPA limited to the airways. Diagnostic work-up and therapy require a multidisciplinary approach. Treatment includes an induction and maintenance phase, combining corticosteroids and immunosuppressive drugs. It aims at limiting the risk of relapses, which is important in GPA, and at reducing corticosteroids toxicity.

La granulomatose avec polyangéite (GPA) fait partie des vasculites associées aux anticorps anti-cytoplasme des polynucléaires neutrophiles (ANCA). La maladie touche principalement la sphère ORL, les poumons et les reins. Son incidence est de 10 à 20 cas/million/année. Les ANCA sont pathogéniques en induisant une activation des polynucléaires neutrophiles, entraînant des lésions endothéliales. Le diagnostic est facilité par la détection des ANCA, qui peuvent cependant être absents dans les formes ORL limitées. La prise en charge est multidisciplinaire. Le traitement comprend une phase d'induction et une autre de maintien de la rémission, associant corticostéroïdes et immunosuppresseurs. L'objectif du traitement est de limiter le risque important de rechute et de réduire la toxicité des corticostéroïdes.

Incidence of new onset glomerulonephritis after SARS-CoV-2 mRNA vaccination is not increased.

Numerous cases of glomerulonephritis manifesting shortly after SARS-CoV-2 vaccination have been reported, but causality remains unproven. Here, we studied the association between mRNA-based SARS-CoV-2 vaccination and new-onset glomerulonephritis using a nationwide retrospective cohort and a case-cohort design. Data from all Swiss pathology institutes processing native kidney biopsies served to calculate incidence of IgA nephropathy, pauci-immune necrotizing glomerulonephritis, minimal change disease, and membranous nephropathy in the adult Swiss population. The observed incidence during the vaccination campaign (January to August 2021) was not different from the expected incidence calculated using a Bayesian model based on the years 2015 to 2019 (incidence rate ratio 0.86, 95% credible interval 0.73-1.02) and did not cross the upper boundary of the 95% credible interval for any month. Among 111 patients 18 years and older with newly diagnosed glomerulonephritis between January and August 2021, 38.7% had received at least one vaccine dose before biopsy, compared to 39.5% of the general Swiss population matched for age and calendar-time. The estimated risk ratio for the development of new-onset biopsy-proven glomerulonephritis was not significant at 0.97 (95% confidence interval 0.66-1.42) in vaccinated vs. unvaccinated individuals. Patients with glomerulonephritis manifesting within four weeks after vaccination did not differ clinically from those manifesting temporally unrelated to vaccination. Thus, vaccination against SARS-CoV-2 was not associated with new-onset glomerulonephritis in these two complementary studies with most temporal associations between SARS-CoV-2 vaccination and glomerulonephritis likely coincidental.

Complement blockade with eculizumab to treat acute symptomatic humoral rejection after heart transplantation.

Antibody-mediated rejection (AMR) is a major barrier preventing successful discordant organ xenotransplantation, but it also occurs in allotransplantation due to anti-HLA antibodies. Symptomatic acute AMR is rare after heart allograft but carries a high risk of mortality, especially >1 year after transplant. As complement activation may play a major role in mediating tissue injury in acute AMR, drugs blocking the terminal complement cascade like eculizumab may be useful, particularly since "standards of care" like plasmapheresis are not based on strong evidence. Eculizumab was successfully used to treat early acute kidney AMR, a typical condition of "active AMR," but showed mitigated results in late AMR, where "chronic active" lesions are more prevalent. Here, we report the case of a heart recipient who presented with acute heart failure due to late acute AMR with eight de novo donor-specific anti-HLA antibodies (DSA), and who fully recovered allograft function and completely cleared DSA following plasmapheresis-free upfront eculizumab administration in addition to thymoglobulin, intravenous immunoglobulins (IVIG), and rituximab. Several clinical (acute onset, abrupt and severe loss of graft function), biological (sudden high-level production of DSA), and pathological features (microvascular injury, C4d deposits) of this cardiac recipient are shared with early kidney AMR and may indicate a strong role of complement in the pathogenesis of acute graft injury that may respond to drugs like eculizumab. Terminal complement blockade should be further explored to treat acute AMR in recipients of heart allografts and possibly also in recipients of discordant xenografts in the future.

A knock-in rat model unravels acute and chronic renal toxicity in glutaric aciduria type I.

Glutaric aciduria type I (GA-I, OMIM # 231670) is an autosomal recessive inborn error of metabolism caused by deficiency of the mitochondrial enzyme glutaryl-CoA dehydrogenase (GCDH). The principal clinical manifestation in GA-I patients is striatal injury most often triggered by catabolic stress. Early diagnosis by newborn screening programs improved survival and reduced striatal damage in GA-I patients. However, the clinical phenotype is still evolving in the aging patient population. Evaluation of long-term outcome in GA-I patients recently identified glomerular filtration rate (GFR) decline with increasing age. We recently created the first knock-in rat model for GA-I harboring the mutation p.R411W (c.1231 C>T), corresponding to the most frequent GCDH human mutation p.R402W. In this study, we evaluated the effect of an acute metabolic stress in form of high lysine diet (HLD) on young Gcdhki/ki rats. We further studied the chronic effect of GCDH deficiency on kidney function in a longitudinal study on a cohort of Gcdhki/ki rats by repetitive 68Ga-EDTA positron emission tomography (PET) renography, biochemical and histological analyses. In young Gcdhki/ki rats exposed to HLD, we observed a GFR decline and biochemical signs of a tubulopathy. Histological analyses revealed lipophilic vacuoles, thinning of apical brush border membranes and increased numbers of mitochondria in proximal tubular (PT) cells. HLD also altered OXPHOS activities and proteome in kidneys of Gcdhki/ki rats. In the longitudinal cohort, we showed a progressive GFR decline in Gcdhki/ki rats starting at young adult age and a decline of renal clearance. Histopathological analyses in aged Gcdhki/ki rats revealed tubular dilatation, protein accumulation in PT cells and mononuclear infiltrations. These observations confirm that GA-I leads to acute and chronic renal damage. This raises questions on indication for follow-up on kidney function in GA-I patients and possible therapeutic interventions to avoid renal damage.

[Pulmonary tumor embolism]. / Embolies pulmonaires tumorales.

Pulmonary tumor embolism is characterized by the occlusion of pulmonary vessels by tumor clots, which can be found in the proximal arteries (macro-embolism) or the small vessels (micro-embolism). The clinical presentation is mainly a progressive dyspnea associated with pulmonary hypertension and subacute cor pulmonale. The diagnosis is difficult, mostly made post-mortem. It is rarely obtained through a combination of multiple diagnostic tests (chest CT, ventilation-perfusion scanning, pulmonary artery cytology, biopsy). Treatment is based on the one of the underlying cancer. The prognosis is poor, and patients usually die within weeks to months. It is a rare cause of pulmonary hypertension that must be considered even without a prior oncological diagnosis.

Les embolies pulmonaires tumorales sont caractérisées par l'occlusion des vaisseaux pulmonaires par des emboles tumoraux pouvant toucher les artères proximales (macroemboles) ou les petits vaisseaux (microemboles). Elles se présentent principalement sous forme d'une dyspnée progressive associée à une hypertension pulmonaire (HTP) et un cœur pulmonaire subaigu. Le diagnostic est difficile, posé le plus souvent post-mortem. Il est rarement obtenu en combinant plusieurs examens (CT-scan thoracique, scintigraphie de ventilation-perfusion, cytologie de l'artère pulmonaire, biopsie). Le traitement repose sur celui de la maladie oncologique sous-jacente. Le pronostic est sombre et les patients décèdent généralement en quelques semaines à quelques mois. C'est une cause rare d'HTP à considérer même en l'absence de diagnostic oncologique préalable.

Upfront use of eculizumab to treat early acute antibody-mediated rejection after kidney allotransplantation and relevance for xenotransplantation.

Acute antibody-mediated rejection (AMR) early after transplant remains a challenge, both in allotransplantation and in xenotransplantation. We report the case of an early and severe acute AMR episode in a kidney transplant recipient that was successfully treated with upfront eculizumab. A 58-year-old woman had been on dialysis since 2014. She underwent a first kidney transplant in 2018 with primary non-function and received several blood transfusions. Postoperatively, she developed anti-HLA antibodies. One year later, she received a second allograft from a deceased donor. At day 0, there was only one preformed low-level donor-specific antibody (DSA) anti-DQ7. After initial excellent allograft function, serum creatinine increased on days 7-9, and this was associated with oligo-anuria. On day 7, there was an increase in her DSA anti-DQ7 and 4 de novo DSA had developed at high MFI values. Allograft biopsy showed severe active AMR with diffuse C4d deposits in peritubular capillaries. The early acute AMR episode was treated with upfront eculizumab administration (2 doses) with efficient CH50 blockade (< 10% CH50). Rituximab was also administered on day 12, and intravenous immunoglobulin (IVIG) was given over the following days. There was an excellent clinical response to eculizumab administration. Eculizumab administration rapidly reversed the acute AMR episode without the need for plasmapheresis. Rituximab and IVIG were also used as B-cell immunomodulators to decrease DSA. Blocking efficiently the terminal complement pathway may become a useful strategy to treat acute AMR in sensitized recipients of allografts, and possibly in recipients of discordant xenografts.

[Immune checkpoint inhibitors and renal toxicity†: update about an emerging pathology]. / Inhibiteurs de points de contrôle immunitaires et atteinte rénale†: mise au point sur une pathologie émergente.

Recently, comprehension of immune mechanisms involved in anti-tumor responses has permitted the development of new oncologic drugs called immune checkpoint inhibitors. These drugs act by restoring anti-tumor responses. With their increasing use, we note a rise in the incidence rate of immune related adverse events, which can affect many organs. Renal toxicity, more precisely tubulointerstitial nephritis, is still not well understood but an emerging complication.

Récemment, la compréhension des mécanismes immuns impliqués dans la réponse antitumorale a permis de développer de nouveaux traitements oncologiques, les inhibiteurs de points de contrôle immunitaires. L'action de ceux-ci repose sur une rupture des mécanismes de tolérance immune envers la tumeur. Avec leur développement, on observe l'apparition d'effets indésirables d'un nouveau genre, s'apparentant à une autoimmunité et touchant différents systèmes. La toxicité rénale, sous la forme d'une néphrite tubulo-interstitielle, est une complication encore méconnue mais émergeante.

Nonvascularized human skin chronic allograft rejection.

A 65-year-old man had extensive burns of the lower legs in 1991, at the age of 40 years. He was treated by nonvascularized and de-epithelialized, allogeneic split-thickness skin allograft and cyclosporine monotherapy for 2 months. Ulcers developed between 10 and 25 years after transplantation and a surgical debridement on the lower extremities was required. Analyses of the removed tissue allografts showed chronic antibody-mediated and cellular rejection with extensive and dense fibrosis, and diffuse capillary C4d deposits. An anti-DRB1*08:01, donor-specific antibody was present. A unique clinical condition with late immunopathological features of human skin chronic allograft rejection is reported.

[Clinical autopsy in Switzerland - a status report]. / Die Klinische Autopsie in der Schweiz ­ ein Statusbericht.

Clinical autopsy in Switzerland - a status report Abstract. The clinical autopsy is an important diagnostic instrument for quality assurance, for education and for the development of medicine in general. In recent decades, however, the number of clinical autopsies required by the clinicians and performed by pathologists has declined dramatically in many countries, including Switzerland. On the other hand, there are numerous efforts, especially from the field of pathology, in part in collaboration with clinical colleagues, aimed at improving the perception of autopsy in the clinic and the public in order to fulfill the duty of providing high quality and modern postmortem diagnostics. These activities include e. g. restructuring, communication concepts, intensified dialogue, as well as technical innovations. However, issues such as ethical, social and financial aspects are difficult and unclear. In this review, some of the activities to improve the state of autopsy in Switzerland are presented, but also relevant issues of the legal and economic framework are discussed.

Renal Fanconi Syndrome and Hypophosphatemic Rickets in the Absence of Xenotropic and Polytropic Retroviral Receptor in the Nephron.

Tight control of extracellular and intracellular inorganic phosphate (Pi) levels is critical to most biochemical and physiologic processes. Urinary Pi is freely filtered at the kidney glomerulus and is reabsorbed in the renal tubule by the action of the apical sodium-dependent phosphate transporters, NaPi-IIa/NaPi-IIc/Pit2. However, the molecular identity of the protein(s) participating in the basolateral Pi efflux remains unknown. Evidence has suggested that xenotropic and polytropic retroviral receptor 1 (XPR1) might be involved in this process. Here, we show that conditional inactivation of Xpr1 in the renal tubule in mice resulted in impaired renal Pi reabsorption. Analysis of Pi transport in primary cultures of proximal tubular cells or in freshly isolated renal tubules revealed that this Xpr1 deficiency significantly affected Pi efflux. Further, mice with conditional inactivation of Xpr1 in the renal tubule exhibited generalized proximal tubular dysfunction indicative of Fanconi syndrome, characterized by glycosuria, aminoaciduria, calciuria, and albuminuria. Dramatic alterations in the renal transcriptome, including a significant reduction in NaPi-IIa/NaPi-IIc expression, accompanied these functional changes. Additionally, Xpr1-deficient mice developed hypophosphatemic rickets secondary to renal dysfunction. These results identify XPR1 as a major regulator of Pi homeostasis and as a potential therapeutic target in bone and kidney disorders.

Absence of nonhematopoietic MHC class II expression protects mice from experimental autoimmune myocarditis.

Experimental autoimmune myocarditis (EAM) is a CD4(+) T-cell-mediated model of human inflammatory dilated cardiomyopathies. Heart-specific CD4(+) T-cell activation is dependent on autoantigens presented by MHC class II (MHCII) molecules expressed on professional APCs. In this study, we addressed the role of inflammation-induced MHCII expression by cardiac nonhematopoietic cells on EAM development. EAM was induced in susceptible mice lacking inducible expression of MHCII molecules on all nonhematopoietic cells (pIV-/- K14 class II transactivator (CIITA) transgenic (Tg) mice) by immunization with α-myosin heavy chain peptide in CFA. Lack of inducible nonhematopoietic MHCII expression in pIV-/- K14 CIITA Tg mice conferred EAM resistance. In contrast, cardiac pathology was induced in WT and heterozygous mice, and correlated with elevated cardiac endothelial MHCII expression. Control mice with myocarditis displayed an increase in infiltrating CD4(+) T cells and in expression of IFN-γ, which is the major driver of nonhematopoietic MHCII expression. Mechanistically, IFN-γ neutralization in WT mice shortly before disease onset resulted in reduced cardiac MHCII expression and pathology. These findings reveal a previously overlooked contribution of IFN-γ to induce endothelial MHCII expression in the heart and to progress cardiac pathology during myocarditis.

Successful therapy with mycophenolic acid in a membranous glomerulonephritis due to Kimura disease
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Kimura disease (KD) is a rare inflammatory soft tissue disorder of unknown origin most frequent in Asians, the prevalence of which is growing in Western countries. Painless papules and/or nodules with a predilection for the head and the neck region, lymphadenopathies, parotid gland involvement, eosinophilia, and raised IgE levels are parts of its presentation. Renal involvement with various forms of glomerulonephritis, including membranous nephropathy (MN), can occur and is generally associated with a proteinuria that encompasses nephrotic syndrome. Corticosteroids are the mainstay of treatment of KD-associated glomerulonephritis, but steroids withdrawal is often followed by relapsing nephrotic syndrome. Various immunosuppressive agents have been tested to prolong the remission of KD-associated nephrotic syndrome while tapering steroids, but they are only partly effective or associated with significant complications. To the best of our knowledge, we describe here the first case of KD-related membranous glomerulonephritis with a favorable evolution and a sustained remission of 4 years under prolonged therapy with mycophenolic acid (MPA). MPA and its active metabolite, mycophenolate mofetil (MMF), treatments as supportive therapies to corticosteroids and ACE inhibitors should be further investigated in KD-related membranous nephropathies.
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Blockade of C5 in Severe Acute Postinfectious Glomerulonephritis Associated With Anti-Factor H Autoantibody.

Activation of the complement cascade plays an important role in the pathogenesis of postinfectious glomerulonephritis. We report successful terminal complement pathway blockade using an anti-C5 monoclonal antibody (eculizumab) in an 8-year-old child with severe acute postinfectious glomerulonephritis requiring hemodialysis. The child presented with clinical, serologic, and histopathologic criteria for diffuse crescentic postinfectious glomerulonephritis. Complement measurements showed low C3 and C4 levels, with increased SC5b-9 titers. The presence of a transient anti-factor H autoantibody was also identified. Eculizumab (600mg, 2 doses at a 1-week interval) was administered, with a striking recovery of kidney function. There were no additional hemodialysis sessions needed after the first dose of eculizumab, and glomerular filtration rate measured using inulin clearance at 12 months of follow-up was within the normal range (92mL/min/1.73m2). Prompt terminal complement blockade may have improved the outcome in this case of severe acute postinfectious glomerulonephritis.

[Chronic kidney diseases do not always pass unnoticed]. / Les maladies rénales chroniques ne sont pas toutes silencieuses!

Kidney diseases are frequent, but most of the time, they develop unnoticed. This paucity of symptoms may lead to delayed diagnosis with important consequences on their outcome. Nevertheless, specific systemic signs such as skin lesions, joint pain or electrolytes disturbances may sometimes alert the clinician and direct the diagnosis to an underlying nephropathy. A high awareness of clinicians is warranted to recognize these red flags and diagnose these diseases early, as illustrated by two clinical cases discussed in this article.

[The role of medical autopsies as a quality control of patients management in internal medicine units]. / Les autopsies médicales comme contrôle de qualité de la prise en charge des patients en médecine interne.

The number of medical autopsies has declined in recent decades due to the development of imaging techniques and some risks linked to autopsies. However, the contribution of autopsy is diagnostically significant, even better than new technologies currently available. It is thus a good indicator of quality, but also a training tool, and has a significant impact in the grieving process. At the CHUV, under the leadership of Pathology Department, institutional projects have been implemented in order to increase the number of autopsies, including a pre- and post-graduate training and systematic request for autopsy, with significant gain for clinicians and pathologists, but also for families who get systematic and customized return results.

Le nombre des autopsies médicales a régressé ces dernières décennies en raison du développement des techniques d'imagerie et de certains risques autour de l'autopsie. Cependant, l'apport de l'autopsie est considérable sur le plan diagnostique, meilleur même que celui des nouvelles technologies actuellement à disposition. Elle représente un bon indicateur de qualité, mais aussi un outil de formation, avec un impact non négligeable dans le processus de deuil des proches. Au CHUV, des projets ont été mis en place en vue d'augmenter le nombre des autopsies : enseignement pré et postgrade et demande systématique lors de chaque décès avec un gain significatif pour les médecins, mais également pour les familles qui bénéficient d'un retour personnalisé des résultats.

PDZ domain-binding motif regulates cardiomyocyte compartment-specific NaV1.5 channel expression and function.

BACKGROUND: Sodium channel NaV1.5 underlies cardiac excitability and conduction. The last 3 residues of NaV1.5 (Ser-Ile-Val) constitute a PDZ domain-binding motif that interacts with PDZ proteins such as syntrophins and SAP97 at different locations within the cardiomyocyte, thus defining distinct pools of NaV1.5 multiprotein complexes. Here, we explored the in vivo and clinical impact of this motif through characterization of mutant mice and genetic screening of patients. METHODS AND RESULTS: To investigate in vivo the regulatory role of this motif, we generated knock-in mice lacking the SIV domain (ΔSIV). ΔSIV mice displayed reduced NaV1.5 expression and sodium current (INa), specifically at the lateral myocyte membrane, whereas NaV1.5 expression and INa at the intercalated disks were unaffected. Optical mapping of ΔSIV hearts revealed that ventricular conduction velocity was preferentially decreased in the transversal direction to myocardial fiber orientation, leading to increased anisotropy of ventricular conduction. Internalization of wild-type and ΔSIV channels was unchanged in HEK293 cells. However, the proteasome inhibitor MG132 rescued ΔSIV INa, suggesting that the SIV motif is important for regulation of NaV1.5 degradation. A missense mutation within the SIV motif (p.V2016M) was identified in a patient with Brugada syndrome. The mutation decreased NaV1.5 cell surface expression and INa when expressed in HEK293 cells. CONCLUSIONS: Our results demonstrate the in vivo significance of the PDZ domain-binding motif in the correct expression of NaV1.5 at the lateral cardiomyocyte membrane and underline the functional role of lateral NaV1.5 in ventricular conduction. Furthermore, we reveal a clinical relevance of the SIV motif in cardiac disease.