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Abstract Background Acute kidney injury (AKI) is frequent among critically ill patients. Renal replacement therapy (RRT) is often required to deal with severe complications of AKI. This technique is however associated with side effects such as hemodynamic instability and delayed renal recovery. In this study, we aimed to describe a novel model of hemodialysis in rats with AKI and depict a dialysis membrane performance. Methods Eighteen Sprague–Dawley rats received 0.75% adenine-rich diet to induce AKI. After 2 weeks, nine underwent an arterio-venous extracorporeal circulation (ECC) (ECC group) for 2 h without a dialysis membrane on the circuit and nine received a hemodialysis session (HD group) for 2 h with an ECC circuit. All rats were hemodynamically monitored, and glomerular filtration rate (GFR) was measured by transcutaneous fluorescence after the injection of FITC-Sinistrin. Blood samples were collected at different time points to assess serum creatinine and serum urea concentrations and to determine the Kt/V. Sinistrin concentration was also quantified in both plasma and dialysis effluent. Results After 2 weeks of adenine-rich diet, rats exhibited a decrease in GFR. Both serum urea and serum creatinine concentrations increased in the ECC group but remained stable in the HD group. We found no significant difference in serum creatinine and serum urea concentrations between groups. At the end of experiments, mean serum urea was 36.7 mmol/l (95%CI 19.7–46.9 mmol/l) and 23.6 mmol/l (95%CI 15.2–33.5 mmol/l) in the ECC and HD groups, respectively (p = 0.15), and mean serum creatinine concentration was 158.0 µmol/l (95%CI 108.1–191.9 µmol/l) and 114.0 µmol/l (95%CI 90.2–140.9 µmol/l) in the ECC and HD groups, respectively (p = 0.11). The Kt/V of the model was estimated at 0.23. Sinistrin quantity in the ultrafiltrate raised steadily during the dialysis session. After 2 h, the median quantity was 149.2 µg (95% CI 99.7–250.3 µg). Conclusions This hemodialysis model is an acceptable compromise between the requirement of hemodynamic tolerance which implies reducing extracorporeal blood volume (using a small dialyzer) and the demonstration that diffusion of molecules through the membrane is achieved.

Abstract Cardiorenal syndromes type 1 and 2 are complex disorders in which cardiac dysfunction leads to kidney dysfunction. However, the mechanisms remain incompletely explained, during pulmonary hypertension in particular. The objective of this study is to develop an original preclinical model of cardiorenal syndrome secondary to a pulmonary hypertension in piglets. Twelve 2-month-old Large White piglets were randomized in two groups: (1) induction of pulmonary hypertension by ligation of the left pulmonary artery and iterative embolizations of the right lower pulmonary artery, or (2) Sham interventions. We evaluated the cardiac function using right heart catheterization, echocardiography and measurement of biochemistry markers). Kidney was characterized using laboratory blood and urine tests, histological evaluation, immunostainings for renal damage and repair, and a longitudinal weekly assessment of the glomerular filtration rate using creatinine-based estimation and intravenous injection of an exogenous tracer on one piglet. At the end of the protocol (6 weeks), the mean pulmonary artery pressure (32 ± 10 vs. 13 ± 2 mmHg; p = 0.001), pulmonary vascular resistance (9.3 ± 4.7 vs. 2.5 ± 0.4 WU; p = 0.004) and central venous pressure were significantly higher in the pulmonary hypertension group while the cardiac index was not different. Piglets with pulmonary hypertension had higher troponin I. We found significant tubular damage and an increase in albuminuria in the pulmonary hypertension group and negative correlation between pulmonary hypertension and renal function. We report here the first porcine model of cardiorenal syndrome secondary to pulmonary hypertension.

Effective neutrophil migration to sites of inflammation is crucial for host immunity. A coordinated cascade of steps allows intravascular leukocytes to counteract the shear stress, transmigrate through the endothelial layer, and move toward the extravascular, static environment. Those events are tightly orchestrated by integrins, but, while the molecular mechanisms leading to their activation have been characterized, the regulatory pathways promoting their detachment remain elusive. In light of this, it has long been known that platelet-endothelial cell adhesion molecule (Pecam1, also known as CD31) deficiency blocks leukocyte transmigration at the level of the outer vessel wall, yet the associated cellular defects are controversial. In this study, we combined an unbiased proteomic study with in vitro and in vivo single-cell tracking in mice to study the dynamics and role of CD31 during neutrophil migration. We found that CD31 localizes to the uropod of migrating neutrophils along with closed β2-integrin and is required for essential neutrophil actin/integrin polarization. Accordingly, the uropod of Pecam1-/- neutrophils is unable to detach from the extracellular matrix, while antagonizing integrin binding to extracellular matrix components rescues this in vivo migratory defect. Conversely, we showed that sustaining CD31 co-signaling actively favors uropod detachment and effective migration of extravasated neutrophils to sites of inflammation in vivo. Altogether, our results suggest that CD31 acts as a molecular rheostat controlling integrin-mediated adhesion at the uropod of egressed neutrophils, thereby triggering their detachment from the outer vessel wall to reach the inflammatory sites.

BackgroundA written action plan (WAP) for managing asthma exacerbations is recommended. ObjectiveWe aimed to compare the effect on unscheduled medical contacts (UMCs) of a digital action plan (DAP) accessed via a smartphone web app combined with a WAP on paper versus that of the same WAP alone. MethodsThis randomized, unblinded, multicenter (offline recruitment in private offices and public hospitals), and parallel-group trial included children (aged 6-12 years) or adults (aged 18-60 years) with asthma who had experienced at least 1 severe exacerbation in the previous year. They were randomized to a WAP or DAP+WAP group in a 1:1 ratio. The DAP (fully automated) provided treatment advice according to the severity and previous pharmacotherapy of the exacerbation. The DAP was an algorithm that recorded 3 to 9 clinical descriptors. In the app, the participant first assessed the severity of their current symptoms on a 10-point scale and then entered the symptom descriptors. Before the trial, the wordings and ordering of these descriptors were validated by 50 parents of children with asthma and 50 adults with asthma; the app was not modified during the trial. Participants were interviewed at 3, 6, 9, and 12 months to record exacerbations, UMCs, and WAP and DAP use, including the subjective evaluation (availability and usefulness) of the action plans, by a research nurse. ResultsOverall, 280 participants were randomized, of whom 33 (11.8%) were excluded because of the absence of follow-up data after randomization, leaving 247 (88.2%) participants (children: n=93, 37.7%; adults: n=154, 62.3%). The WAP group had 49.8% (123/247) of participants (children: n=45, 36.6%; mean age 8.3, SD 2.0 years; adults: n=78, 63.4%; mean age 36.3, SD 12.7 years), and the DAP+WAP group had 50.2% (124/247) of participants (children: n=48, 38.7%; mean age 9.0, SD 1.9 years; adults: n=76, 61.3%; mean age 34.5, SD 11.3 years). Overall, the annual severe exacerbation rate was 0.53 and not different between the 2 groups of participants. The mean number of UMCs per year was 0.31 (SD 0.62) in the WAP group and 0.37 (SD 0.82) in the DAP+WAP group (mean difference 0.06, 95% CI −0.12 to 0.24; P=.82). Use per patient with at least 1 moderate or severe exacerbation was higher for the WAP (33/65, 51% vs 15/63, 24% for the DAP; P=.002). Thus, participants were more likely to use the WAP than the DAP despite the nonsignificant difference between the action plans in the subjective evaluation. Median symptom severity of the self-evaluated exacerbation was 4 out of 10 and not significantly different from the symptom severity assessed by the app. ConclusionsThe DAP was used less often than the WAP and did not decrease the number of UMCs compared with the WAP alone. Trial RegistrationClinicalTrials.gov NCT02869958; https://clinicaltrials.gov/ct2/show/NCT02869958

Abstract A recent article described a thickening of the glomerular basement membrane (GBM) along with changes in the expression of key components of the extracellular matrix in 6‐month‐old NPHS2‐Cre transgenic mice, which express the Cre recombinase specifically in podocytes. This transgenic line has been widely used to characterize the implication of candidate genes in glomerular diseases in younger mice. Using a different mouse strain (C57BL/6J) than the previous report (129S6/SvEvTac), we sought to characterize 3‐ and 6‐month‐old NPHS2‐Cre+/− mice in control and pathological conditions. At baseline, there was no difference in renal function and histology between control and NPHS2‐Cre+/− mice. Notably, GBM thickness evaluated by transmission electron microscopy was similar between the two groups. We then induced an immune‐mediated severe glomerular insult, the anti‐glomerular basement membrane glomerulonephritis model (anti‐GBM‐GN) in 3‐month‐old control and NPHS2‐Cre+/− mice. NPHS2‐Cre+/− mice exhibited the same alterations in renal function and structure as control mice. In summary, our study strongly suggests that NPHS2‐Cre+/− transgenic mice on a C57BL/6J background can be safely used for podocyte‐specific gene inactivation in control conditions and in the anti‐GBM‐GN model.

Author(s): Guillaume Dorval [sup.1] [sup.2] , Alice Hadchouel [sup.2] [sup.3] , Nathalie Biebuyck-Gougé [sup.1] [sup.2] , Henri Giniès [sup.1] , Marion Rabant [sup.2] [sup.4] , Laureline Berteloot [sup.2] [sup.5] , [...]

L-Methionine (Met) is an essential alpha-amino acid playing a key role in several metabolic pathways. Rare inherited metabolic diseases such as mutations affecting the MARS1 gene encoding methionine tRNA synthetase (MetRS) can cause severe lung and liver disease before the age of two years. Oral Met therapy has been shown to restore MetRS activity and improve clinical health in children. As a sulfur-containing compound, Met has a strongly unpleasant odor and taste. The objective of this study was to develop an optimized pediatric pharmaceutical formulation of Met powder, to be reconstituted with water, to obtain a stable oral suspension. Organoleptic characteristics and physicochemical stability of the powdered Met formulation and suspension were evaluated at three storage temperatures. Met quantification was assessed by a stability-indicating chromatographic method as well as microbial stability. The use of a specific fruit flavor (e.g., strawberry) with sweeteners (e.g., sucralose) was considered acceptable. No drug loss, pH changes, microbiological growth, or visual changes were observed at 23 ± 2 °C and 4 ± 2 °C with the powder formulation for 92 days, and the reconstituted suspension for at least 45 days. The developed formulation facilitates the preparation, administration, the dose adjustment and palatability of Met treatment in children.

Vascular Ehlers-Danlos syndrome is a rare inherited disorder caused by genetic variants in type III collagen. Its prognosis is especially hampered by unpredictable arterial ruptures and there is no therapeutic consensus. We created a knock-in Col3a1+/G182R mouse model and performed a complete genetic, molecular and biochemical characterization. Several therapeutic strategies were also tested. Col3a1+/G182R mice showed a spontaneous mortality caused by thoracic aortic rupture that recapitulates the vascular Ehlers-Danlos syndrome with a lower survival rate in males, thin non-inflammatory arteries and an altered arterial collagen. Transcriptomic analysis of aortas showed upregulation of genes related to inflammation and cell stress response. Compared to water, survival rate of Col3a1+/G182R mice was not affected by beta-blockers (propranolol or celiprolol). Two other vasodilating anti-hypertensive agents (hydralazine, amlodipine) gave opposite results on aortic rupture and mortality rate. There was a spectacular beneficial effect of losartan, reversed by the cessation of its administration, and a marked deleterious effect of exogenous angiotensin II. These results suggest that blockade of the renin angiotensin system should be tested as a first-line medical therapy in patients with vascular Ehlers-Danlos syndrome.

Gain-of-function mutations in with no lysine (K)1 (WNK1) and WNK4genes are responsible for familial hyperkalemic hypertension (FHHt), a rare, inherited disorder characterized by arterial hypertension and hyperkalemia with metabolic acidosis. More recently, FHHt-causing mutations in the Kelch-like 3-Cullin 3 (KLHL3-CUL3) E3 ubiquitin ligase complex have shed light on the importance of WNK's cellular degradation on renal ion transport. Using full exome sequencing for a 4-generation family and then targeted sequencing in other suspected cases, we have identified new missense variants in the WNK1 gene clustering in the short conserved acidic motif known to interact with the KLHL3-CUL3 ubiquitin complex. Affected subjects had an early onset of a hyperkalemic hyperchloremic phenotype, but normal blood pressure values' Functional experiments in Xenopus laevis oocytes and HEK293T cells demonstrated that these mutations strongly decrease the ubiquitination of the kidney-specific isoform KS-WNK1 by the KLHL3-CUL3 complex rather than the long ubiquitous catalytically active L-WNK1 isoform. A corresponding CRISPR/Cas9 engineered mouse model recapitulated both the clinical and biological phenotypes. Renal investigations showed increased activation of the Ste20 proline alanine-rich kinase-[Na.sup.+]-[Cl.sup.-] cotransporter (SPAK-NCC) phosphorylation cascade, associated with impaired ROMK apical expression in the distal part of the renal tubule. Together, these new WNK1 genetic variants highlight the importance of the KS-WNK1 isoform abundance on potassium homeostasis., Introduction Familial hyperkalemic hypertension (FHHt), also known as Gordon syndrome and pseudohypoaldosteronism type 2, is a rare disease associated with net positive [Na.sup.+] balance and renal [K.sup.+] retention resulting in [...]

Abstract Background The pathophysiology of congenital cystic adenomatoid malformations (CCAM) of the lung remains poorly understood. Aim This study aimed to identify more precisely the molecular mechanisms limited to a compartment of lung tissue, through a transcriptomic analysis of the epithelium of macrocystic forms. Methods Tissue fragments displaying CCAM were obtained during planned surgical resections. Epithelial mRNA was obtained from cystic and normal areas after laser capture microdissection (LCM). Transcriptomic analyses were performed and the results were confirmed by RT-PCR and immunohistochemistry in independent samples. Results After controlling for RNA quality, we analysed the transcriptomes of six cystic areas and five control areas. In total, 393 transcripts were differentially expressed in the epithelium, between CCAM and control areas. The most highly redundant genes involved in biological functions and signalling pathways differentially expressed between CCAM and control epithelium included TGFB2, TGFBR1, and MAP 2 K1. These genes were considered particularly relevant as they have been implicated in branching morphogenesis. RT-qPCR analysis confirmed in independent samples that TGFBR1 was more strongly expressed in CCAM than in control tissues (p

Renin is the key enzyme of the systemic renin–angiotensin–aldosterone system, which plays an essential role in regulating blood pressure and maintaining electrolyte and extracellular volume homeostasis. Renin is mainly produced and secreted by specialized juxtaglomerular (JG) cells in the kidney. In the present study, we report for the first time that the conserved transmembrane receptor neuropilin‐1 (NRP1) participates in the development of JG cells and plays a key role in renin production. We used the myelin protein zero‐Cre (P0‐Cre) to abrogate Nrp1 constitutively in P0‐Cre lineage‐labelled cells of the kidney. We found that the P0‐Cre precursor cells differentiate into renin‐producing JG cells. We employed a lineage‐tracing strategy combined with RNAscope quantification and metabolic studies to reveal a cell‐autonomous role for NRP1 in JG cell function. Nrp1‐deficient animals displayed abnormal levels of tissue renin expression and failed to adapt properly to a homeostatic challenge to sodium balance. These findings provide new insights into cell fate decisions and cellular plasticity operating in P0‐Cre–expressing precursors and identify NRP1 as a novel key regulator of JG cell maturation. Key points: Renin is a centrepiece of the renin–angiotensin–aldosterone system and is produced by specialized juxtaglomerular cells (JG) of the kidney.Neuropilin‐1 (NRP1) is a conserved membrane‐bound receptor that regulates vascular and neuronal development, cancer aggressiveness and fibrosis progression.We used conditional mutagenesis and lineage tracing to show that NRP1 is expressed in JG cells where it regulates their function.Cell‐specific Nrp1 knockout mice present with renin paucity in JG cells and struggle to adapt to a homeostatic challenge to sodium balance.The results support the versatility of renin‐producing cells in the kidney and may open new avenues for therapeutic approaches. [ABSTRACT FROM AUTHOR]

Acute kidney injury activates both proliferative and antiproliferative pathways, the consequences of which are not fully elucidated. If an initial proliferation of the renal epithelium is necessary for the successful repair, the persistence of proliferation markers is associated with the occurrence of chronic kidney disease. We hypothesized that proliferation in stress conditions impacts cell viability and renal outcomes. We found that proliferation is associated with cell death after various stresses in kidney cells. In vitro, the ATP/ADP ratio oscillates reproducibly throughout the cell cycle, and cell proliferation is associated with a decreased intracellular ATP/ADP ratio. In vivo, transcriptomic data from transplanted kidneys revealed that proliferation was strongly associated with a decrease in the expression of the mitochondria-encoded genes of the oxidative phosphorylation pathway, but not of the nucleus-encoded ones. These observations suggest that mitochondrial function is a limiting factor for energy production in proliferative kidney cells after injury. The association of increased proliferation and decreased mitochondrial function was indeed associated with poor renal outcomes. In summary, proliferation is an energy-demanding process impairing the cellular ability to cope with an injury, highlighting proliferative repair and metabolic recovery as indispensable and interdependent features for successful kidney repair. [ABSTRACT FROM AUTHOR]

Pleuropulmonary blastoma (PPB) is a very rare pediatric lung disease. It can progress from abnormal epithelial cysts to an aggressive sarcoma with poor survival. PPB is difficult to diagnose as it can be confounded with other cystic lung disorders, such as congenital pulmonary airway malformation (CPAM). PPB is associated with mutations in DICER1 that perturb the microRNA (miRNA) profile in lung. How DICER1 and miRNAs act during PPB pathogenesis remains unsolved. Lung epithelial deletion of the Yin Yang1 (Yy1) gene in mice causes a phenotype mimicking the cystic form of PPB and affects the expression of key regulators of lung development. Similar changes in expression were observed in PPB but not in CPAM lung biopsies, revealing a distinctive PPB molecular signature. Deregulation of molecules promoting epithelial–mesenchymal transition (EMT) was detected in PPB specimens, suggesting that EMT might participate in tumor progression. Changes in miRNA expression also occurred in PPB lung biopsies. miR-125a-3p, a candidate to regulate YY1 expression and lung branching, was abnormally highly expressed in PPB samples. Together, these findings support the concept that reduced expression of YY1, due to the abnormal miRNA profile resulting from DICER1 mutations, contributes to PPB development via its impact on the expression of key lung developmental genes. This article has an associated First Person interview with the joint first authors of the paper.

BackgroundThe use of simulation games (SG) to assess the clinical competence of medical students has been poorly studied. ObjectiveThe objective of this study was to assess whether an SG better reflects the clinical competence of medical students than a multiple choice questionnaire (MCQ). MethodsFifth-year medical students in Paris (France) were included and individually evaluated on a case of pediatric asthma exacerbation using three successive modalities: high-fidelity simulation (HFS), considered the gold standard for the evaluation of clinical competence, the SG Effic’Asthme, and an MCQ designed for the study. The primary endpoint was the median kappa coefficient evaluating the correlation of the actions performed by the students between the SG and HFS modalities and the MCQ and HFS modalities. Student satisfaction was also evaluated. ResultsForty-two students were included. The actions performed by the students were more reproducible between the SG and HFS modalities than between the MCQ and HFS modalities (P=.04). Students reported significantly higher satisfaction with the SG (P