Retrospective study of 59 cases of cancer-associated thrombotic microangiopathy: presentation and treatment characteristics.

BACKGROUND: Cancer-associated thrombotic microangiopathy (TMA) is a rare disease, with a poor prognosis. The classical treatment is urgent chemotherapy. Few data are available on the efficacy of plasma exchange (PE) and eculizumab in these patients. METHODS: Cases of cancer-related TMA treated between January 2008 and December 2019 in 12 French treatment centres were retrospectively analysed, excluding cases associated with chemotherapy and stem cell transplantation. Patients were divided into four groups depending on the treatment received: none, PE therapy alone, chemotherapy, with or without PE therapy, or eculizumab, with or without chemotherapy and PE therapy. RESULTS: The data of 59 patients with cancer-associated TMA were analysed. Twenty of these cases were related to a cancer recurrence. The cancer was metastatic in 90% of cases (53/59). Bone marrow invasion was observed in 20/41 biopsies. Some laboratory results, including disseminated intravascular coagulation high ferritin and C-reactive protein, were suggestive of cancer. None of the 16 patients whose alternative complement pathway was assessed had abnormal levels of protein expression or activity. The median survival time was 27 days. Chemotherapy was significantly associated with improved survival, with a 30-day survival rate of 85% (17/20) among patients who received PE and chemotherapy, versus 20% (3/15) among patients who received PE alone. Patients treated with eculizumab in addition to chemotherapy and PE therapy did not have longer overall survival or higher haematological remission rates than those treated with chemotherapy and PE therapy alone. Renal remission rates were non-significantly higher, and times to remission non-significantly shorter, in the eculizumab group. CONCLUSIONS: Nephrologists and oncologists should make themselves aware of cancer diagnoses in patients with TMA and bone marrow biopsies should be performed systematically in these cases. All 59 patients had poor survival outcomes, but patients treated with urgent initiation of chemotherapy survived significantly longer than those who were not.

Mechanisms of myostatin and activin A accumulation in chronic kidney disease.

BACKGROUND: Myostatin and activin A induce muscle wasting by activating the ubiquitin proteasome system and inhibiting the Akt/mammalian target of rapamycin pathway. In chronic kidney disease (CKD), myostatin and activin A plasma concentrations are increased, but it is unclear if there is increased production or decreased renal clearance. METHODS: We measured myostatin and activin A concentrations in 232 CKD patients and studied their correlation with estimated glomerular filtration rate (eGFR). We analyzed the myostatin gene (MSTN) expression in muscle biopsies of hemodialysis (HD) patients. We then measured circulating myostatin and activin A in plasma and the Mstn and Inhba expression in muscles, kidney, liver and heart of two CKD mice models (adenine and 5/6 nephrectomy models). Finally, we analyzed whether the uremic toxin indoxyl sulfate (IS) increased Mstn expression in mice and cultured muscle cells. RESULTS: In patients, myostatin and activin A were inversely correlated with eGFR. MSTN expression was lower in HD patients' muscles (vastus lateralis) than in controls. In mice with CKD, myostatin and activin A blood concentrations were increased. Mstn was not upregulated in CKD mice tissues. Inha was upregulated in kidney and heart. Exposure to IS did not induce Mstn upregulation in mouse muscles and in cultured myoblasts and myocytes. CONCLUSION: During CKD, myostatin and activin A blood concentrations are increased. Myostatin is not overproduced, suggesting only an impaired renal clearance, but activin A is overproduced in the kidney and heart. We propose to add myostatin and activin A to the list of uremic toxins.

Neutrophil:lymphocyte ratio correlates with the uremic toxin indoxyl sulfate and predicts the risk of death in patients on hemodialysis.

BACKGROUND: Chronic kidney disease (CKD) is a major public health issue associated with increased cardiovascular, infectious and all-cause mortality. The neutrophil:lymphocyte ratio (NLR) is a predictive marker of the risk of death and cardiovascular events. Uremic toxins, notably indoxyl sulfate (IS), are involved in immune deficiency and cardiovascular complications associated with CKD. The aim of this study was to assess whether the NLR was related to uremic toxins and could predict clinical outcome in hemodialysis (HD) patients. METHODS: We conducted a prospective cohort study of 183 patients on chronic HD. The main objective was to study the correlation between the NLR and uremic toxin serum levels. The secondary objective was to test if the NLR can predict the incidence of mortality, cardiovascular events and infectious events. RESULTS: Patients were separated into two groups according to the NLR median value (3.49). The NLR at inclusion was correlated with the NLR at the 6-month (r = 0.55, P < 0.0001) and 12-month (r = 0.62, P < 0.0001) follow-up. Among uremic toxins, IS levels were higher in the group with high NLR (104 µmol/L versus 81 µmol/L; P = 0.004). In multivariate analysis, the NLR remained correlated with IS (P = 0.03). The incidence of death, cardiovascular events and severe infectious events was higher in the group with high NLR [respectively, 38% versus 18% (P = 0.004), 45% versus 26% (P = 0.01) and 33% versus 21% (P = 0.02)] than in the low NLR group. Multivariate analysis showed an independent association of the NLR with mortality (P = 0.02) and cardiovascular events (P = 0.03) but not with severe infectious events. CONCLUSIONS: In HD patients, the NLR predicted mortality and cardiovascular events but not severe infections and correlated positively with the level of the uremic toxin IS. The NLR could be an interesting marker for monitoring the risk of clinical events in CKD patients.

Acute kidney injury in patients treated with anti-programmed death receptor-1 for advanced melanoma: a real-life study in a single-centre cohort.

BACKGROUND: Immune checkpoints inhibitors have transformed the prognosis of advanced melanoma but are associated with immune-related adverse events (irAEs). We evaluated the incidence, risk factors and causes of acute kidney injury (AKI) in a monocentric real-life cohort of patients treated with anti-programmed death receptor-1 (anti-PD1) antibodies for advanced melanoma. METHODS: Retrospective collection of medical charts and comprehensive analysis of lab results from patients treated with nivolumab or pembrolizumab for advanced melanoma between 2014 and 2018 was carried out. AKI was defined by Kidney Disease Improving Global Outcomes criteria, and causes were determined by chart review. Overall survival, survival without AKI and impact of AKI on survival were analysed. Risk factors for death and for AKI were identified. RESULTS: Two hundred and thirty-nine patients were included. Forty-one (17%) had at least one episode of AKI. Independent risk factors for AKI were treatment with renin-angiotensin-aldosterone system inhibitors (RAASi), pre-existing chronic kidney disease (CKD) and cumulated doses of anti-PD1. The main cause of AKI was prerenal, and only eight patients (3.3%) developed acute interstitial nephritis; 8% of patients developed CKD. The median overall survival was 13.4 months and was not affected by AKI. In multivariate analysis, the overall mortality was lower in overweight and obese patients and higher in patients treated with proton-pump inhibitors (PPI) or corticosteroids. CONCLUSIONS: AKI is common in patients treated with anti-PD1 for advanced melanoma but is mostly prerenal and favoured by the use of RAASi; renal irAE is rare. PPI and corticosteroids were associated with poor survival in this population, while overweight/obesity was protective.

Thrombotic microangiopathy associated with gemcitabine use: Presentation and outcome in a national French retrospective cohort.

AIMS: Gemcitabine has been associated with thrombotic microangiopathy (TMA). We conducted a national retrospective study of gemcitabine-associated TMA (G-TMA). METHODS: From 1998 to 2015, all cases of G-TMA reported to the French Pharmacovigilance Network and the French TMA Reference Center, and cases explored for complement alternative pathway abnormalities, were analysed. RESULTS: G-TMA was diagnosed in 120 patients (median age 61.5 years), after a median of 210 days of treatment, and a cumulative dose of 12 941 mg m-2 . Gemcitabine indications were: pancreatic (52.9%), pulmonary (12.6%) and breast (7.6%) cancers, metastatic in 34.2% of cases. Main symptoms were oedema (56.7%) and new-onset or exacerbated hypertension (62.2%). Most patients presented with haemolytic anaemia (95.6%) and thrombocytopenia (74.6%). Acute kidney injury was reported in 97.4% and dialysis was required in 27.8% of patients. Treatment consisted of: plasma exchange (PE; 39.8%), fresh frozen plasma (21.4%), corticosteroids (15.3%) and eculizumab (5.1%). A complete remission of TMA was obtained in 42.1% of patients and haematological remission in 23.1%, while 34.7% did not improve. The survival status was known for 52 patients, with 29 deaths (54.7%). Patients treated with PE, despite a more severe acute kidney injury, requiring dialysis more frequently, displayed comparable rates of remission, but with more adverse events. No abnormality in complement alternative pathway was documented in patients explored. CONCLUSION: This large cohort confirms the severity of G-TMA, associated with severe renal failure and death. Oedema and hypertension could be monitored in patients treated with gemcitabine to detect early TMA. The benefit of PE or eculizumab deserves further investigation.

Aryl hydrocarbon receptor is activated in patients and mice with chronic kidney disease.

Patients with chronic kidney disease (CKD) are exposed to uremic toxins and have an increased risk of cardiovascular disease. Some uremic toxins, like indoxyl sulfate, are agonists of the transcription factor aryl hydrocarbon receptor (AHR). These toxins induce a vascular procoagulant phenotype. Here we investigated AHR activation in patients with CKD and in a murine model of CKD. We performed a prospective study in 116 patients with CKD stage 3 to 5D and measured the AHR-Activating Potential of serum by bioassay. Compared to sera from healthy controls, sera from CKD patients displayed a strong AHR-Activating Potential; strongly correlated with eGFR and with the indoxyl sulfate concentration. The expression of the AHR target genes Cyp1A1 and AHRR was up-regulated in whole blood from patients with CKD. Survival analyses revealed that cardiovascular events were more frequent in CKD patients with an AHR-Activating Potential above the median. In mice with 5/6 nephrectomy, there was an increased serum AHR-Activating Potential, and an induction of Cyp1a1 mRNA in the aorta and heart, absent in AhR-/- CKD mice. After serial indoxyl sulfate injections, we observed an increase in serum AHR-AP and in expression of Cyp1a1 mRNA in aorta and heart in WT mice, but not in AhR-/- mice. Thus, the AHR pathway is activated both in patients and mice with CKD. Hence, AHR activation could be a key mechanism involved in the deleterious cardiovascular effects observed in CKD.

Clinical and genetic heterogeneity in familial steroid-sensitive nephrotic syndrome.

BACKGROUND: Familial steroid-sensitive nephrotic syndrome (SSNS) is a rare condition. The disease pathophysiology remains elusive. However, bi-allelic mutations in the EMP2 gene were identified, and specific variations in HLA-DQA1 were linked to a high risk of developing the disease. METHODS: Clinical data were analyzed in 59 SSNS families. EMP2 gene was sequenced in families with a potential autosomal recessive (AR) inheritance. Exome sequencing was performed in a subset of 13 families with potential AR inheritance. Two variations in HLA-DQA1 were genotyped in the whole cohort. RESULTS: Transmission was compatible with an AR (n = 33) or autosomal dominant (AD, n = 26) inheritance, assuming that familial SSNS is a monogenic trait. Clinical features did not differ between AR and AD groups. All patients, including primary (n = 7) and secondary steroid resistant nephrotic syndrone (SRNS), (n = 13) were sensitive to additional immunosuppressive therapy. Both HLA-DQA1 variations were found to be highly linked to the disease (OR = 4.34 and OR = 4.89; p < 0.001). Exome sequencing did not reveal any pathogenic mutation, neither did EMP2 sequencing. CONCLUSIONS: Taken together, these results highlight the clinical and genetic heterogeneity in familial SSNS. Clinical findings sustain an immune origin in all patients, whatever the initial steroid-sensitivity. The absence of a variant shared by two families and the HLA-DQA1 variation enrichments suggest a complex mode of inheritance.

Indole 3-acetic acid, indoxyl sulfate and paracresyl-sulfate do not influence anemia parameters in hemodialysis patients.

BACKGROUND: The main reason for anemia in renal failure patients is the insufficient erythropoietin production by the kidneys. Beside erythropoietin deficiency, in vitro studies have incriminated uremic toxins in the pathophysiology of anemia but clinical data are sparse. In order to assess if indole 3-acetic acid (IAA), indoxyl sulfate (IS), and paracresyl sulfate (PCS) -three protein bound uremic toxins- are clinically implicated in end-stage renal disease anemia we studied the correlation between IAA, IS and PCS plasmatic concentrations with hemoglobin and Erythropoietin Stimulating Agents (ESA) use in hemodialysis patients. METHODS: Between June and July 2014, we conducted an observational cross sectional study in two hemodialysis center. Three statistical approaches were conducted. First, we compared patients treated with ESA and those not treated. Second, we performed linear regression models between IAA, IS, and PCS plasma concentrations and hemoglobin, the ESA dose over hemoglobin ratio (ESA/Hemoglobin) or the ESA resistance index (ERI). Third, we used a polytomous logistic regression model to compare groups of patients with no/low/high ESA dose and low/high hemoglobin statuses. RESULTS: Overall, 240 patients were included in the study. Mean age ± SD was 67.6 ± 16.0 years, 55.4% were men and 42.5% had diabetes mellitus. When compared with ESA treated patients, patients with no ESA had higher hemoglobin (mean 11.4 ± 1.1 versus 10.6 ± 1.2 g/dL; p <0.001), higher transferrin saturation (TSAT, 31.1 ± 16.3% versus 23.1 ± 11.5%; p < 0.001), less frequently an IV iron prescription (52.1 versus 65.7%, p = 0.04) and were more frequently treated with hemodiafiltration (53.5 versus 36.7%). In univariate analysis, IAA, IS or PCS plasma concentrations did not differ between the two groups. In the linear model, IAA plasma concentration was not associated with hemoglobin, but was negatively associated with ESA/Hb (p = 0.02; R = 0.18) and with the ERI (p = 0.03; R = 0.17). IS was associated with none of the three anemia parameters. PCS was positively associated with hemoglobin (p = 0.03; R = 0.14), but negatively with ESA/Hb (p = 0.03; R = 0.17) and the ERI (p = 0.02; R = 0.19). In multivariate analysis, the association of IAA concentration with ESA/Hb or ERI was not statistically significant, neither was the association of PCS with ESA/Hb or ERI. Identically, in the subgroup of 76 patients with no inflammation (CRP <5 mg/L) and no iron deficiency (TSAT >20%) linear regression between IAA, IS or PCS and any anemia parameter did not reach significance. In the third model, univariate analysis showed no intergroup significant differences for IAA and IS. Regarding PCS, the Low Hb/High ESA group had lower concentrations. However, when we compared PCS with the other significant characteristics of the five groups to the Low Hb/high ESA (our reference group), the polytomous logistic regression model didn't show any significant difference for PCS. CONCLUSIONS: In our study, using three different statistical models, we were unable to show any correlation between IAA, IS and PCS plasmatic concentrations and any anemia parameter in hemodialysis patients. Indolic uremic toxins and PCS have no or a very low effect on anemia parameters.

The cardiovascular effect of the uremic solute indole-3 acetic acid.

In CKD, uremic solutes may induce endothelial dysfunction, inflammation, and oxidative stress, leading to increased cardiovascular risk. We investigated whether the uremic solute indole-3 acetic acid (IAA) predicts clinical outcomes in patients with CKD and has prooxidant and proinflammatory effects. We studied 120 patients with CKD. During the median study period of 966 days, 29 patients died and 35 experienced a major cardiovascular event. Kaplan-Meier analysis revealed that mortality and cardiovascular events were significantly higher in the higher IAA group (IAA>3.73 µM) than in the lower IAA group (IAA<3.73 µM). Multivariate Cox regression analysis demonstrated that serum IAA was a significant predictor of mortality and cardiovascular events after adjustments for age and sex; cholesterol, systolic BP, and smoking; C-reactive protein, phosphate, body mass index, and albumin; diastolic BP and history of cardiovascular disease; and uremic toxins p-cresyl sulfate and indoxyl sulfate. Notably, IAA level remained predictive of mortality when adjusted for CKD stage. IAA levels were positively correlated with markers of inflammation and oxidative stress: C-reactive protein and malondialdehyde, respectively. In cultured human endothelial cells, IAA activated an inflammatory nongenomic aryl hydrocarbon receptor (AhR)/p38MAPK/NF-κB pathway that induced the proinflammatory enzyme cyclooxygenase-2. Additionally, IAA increased production of endothelial reactive oxygen species. In conclusion, serum IAA may be an independent predictor of mortality and cardiovascular events in patients with CKD. In vitro, IAA induces endothelial inflammation and oxidative stress and activates an inflammatory AhR/p38MAPK/NF-κB pathway.

Immunoadsorption and Plasma Exchange are Comparable in Anti-Neutrophil Cytoplasmic Antibodies or Anti-Glomerular Basement Membrane Removal Kinetics.

Introduction: Apheresis allows the fast removal of autoantibodies in anti-glomerular basement membrane (anti-GBM) disease, and in severe antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis. The CINEVAS study tested whether immunoadsorption (IA) allowed a faster removal of ANCA and/or anti-GBM antibodies than plasma exchanges (PEx). Methods: CINEVAS was a prospective multicenter study comparing IA to PEx in consecutive patients with ANCA and/or anti-GBM vasculitides. The primary objective was the reduction rate in autoantibody titers between the beginning of the first and the end of the seventh apheresis session. Secondary objectives were number of sessions needed to obtain desired reduction rates; reduction rates of total Ig levels; tolerance of sessions; and patients' outcome. Results: The results of 38 patients (16 treated with IA and 22 with PEx), and 43 autoantibodies, were analyzed. There was no difference in the reduction rates in autoantibody titers between IA and PEx over 7 sessions (respectively 98% vs. 96%, P = 0.39). The numbers of sessions needed to obtain undetectable autoantibodies, or 50%, 75%, or 90% reductions, did not differ between techniques. Greater reduction rates of autoantibodies were observed when plasma was separated by filtration compared to centrifugation, with IA and PEx. IA allowed a greater reduction in total IgG levels, and better preservation of total IgA and IgM levels than PEx. PEx sessions required higher volumes of plasma, IA sessions higher volumes of citrate; IA sessions were longer. Conclusions: IA and PEx were comparable in ANCA or anti-GBM removal kinetics, despite a faster reduction in total IgG with IA.