Cell cycle arrest and p53 prevent ON-target megabase-scale rearrangements induced by CRISPR-Cas9.

The CRISPR-Cas9 system has revolutionized our ability to precisely modify the genome and has led to gene editing in clinical applications. Comprehensive analysis of gene editing products at the targeted cut-site has revealed a complex spectrum of outcomes. ON-target genotoxicity is underestimated with standard PCR-based methods and necessitates appropriate and more sensitive detection methods. Here, we present two complementary Fluorescence-Assisted Megabase-scale Rearrangements Detection (FAMReD) systems that enable the detection, quantification, and cell sorting of edited cells with megabase-scale loss of heterozygosity (LOH). These tools reveal rare complex chromosomal rearrangements caused by Cas9-nuclease and show that LOH frequency depends on cell division rate during editing and p53 status. Cell cycle arrest during editing suppresses the occurrence of LOH without compromising editing. These data are confirmed in human stem/progenitor cells, suggesting that clinical trials should consider p53 status and cell proliferation rate during editing to limit this risk by designing safer protocols.

Melatonin: Facts, Extrapolations and Clinical Trials.

Melatonin is a fascinating molecule that has captured the imagination of many scientists since its discovery in 1958. In recent times, the focus has changed from investigating its natural role as a transducer of biological time for physiological systems to hypothesized roles in virtually all clinical conditions. This goes along with the appearance of extensive literature claiming the (generally) positive benefits of high doses of melatonin in animal models and various clinical situations that would not be receptor-mediated. Based on the assumption that melatonin is safe, high doses have been administered to patients, including the elderly and children, in clinical trials. In this review, we critically review the corresponding literature, including the hypotheses that melatonin acts as a scavenger molecule, in particular in mitochondria, by trying not only to contextualize these interests but also by attempting to separate the wheat from the chaff (or the wishful thinking from the facts). We conclude that most claims remain hypotheses and that the experimental evidence used to promote them is limited and sometimes flawed. Our review will hopefully encourage clinical researchers to reflect on what melatonin can and cannot do and help move the field forward on a solid basis.

Southern ocean carbon and heat impact on climate.

The Southern Ocean greatly contributes to the regulation of the global climate by controlling important heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal timescales are therefore impacted by oceanic processes taking place in the Southern Ocean, yet too little is known about these processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent processes at scales that are not well captured in current Earth system models. The Southern Ocean Carbon and Heat Impact on Climate programme was launched to address this knowledge gap, with the overall objective to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches. Here, we provide a brief overview of the programme, as well as a summary of some of the scientific progress achieved during its first half. Advances range from new evidence of the importance of specific processes in Southern Ocean ventilation rate (e.g. storm-induced turbulence, sea-ice meltwater fronts, wind-induced gyre circulation, dense shelf water formation and abyssal mixing) to refined descriptions of the physical changes currently ongoing in the Southern Ocean and of their link with global climate. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.

Particulate suspension coating of capillary tubes.

The displacement of a suspension of particles by an immiscible fluid in a capillary tube or in porous media is a canonical configuration that finds application in a large number of natural and industrial applications, including water purification, dispersion of colloids and microplastics, coating and functionalization of tubings. The influence of particles dispersed in the fluid on the interfacial dynamics and on the properties of the liquid film left behind remain poorly understood. Here, we study the deposition of a coating film on the walls of a capillary tube induced by the translation of a suspension plug pushed by air. We identify the different deposition regimes as a function of the translation speed of the plug, the particle size, and the volume fraction of the suspension. The thickness of the coating film is characterized, and we show that similarly to dip coating, three coating regimes are observed, liquid only, heterogeneous, and thick films. We also show that, at first order, the thickness of films thicker than the particle diameter can be predicted using the effective viscosity of the suspension. Nevertheless, we also report that for large particles and concentrated suspensions, a shear-induced migration mechanism leads to local variations in volume fraction and modifies the deposited film thickness and composition.

CRISPR-Cas9 globin editing can induce megabase-scale copy-neutral losses of heterozygosity in hematopoietic cells.

CRISPR-Cas9 is a promising technology for gene therapy. However, the ON-target genotoxicity of CRISPR-Cas9 nuclease due to DNA double-strand breaks has received little attention and is probably underestimated. Here we report that genome editing targeting globin genes induces megabase-scale losses of heterozygosity (LOH) from the globin CRISPR-Cas9 cut-site to the telomere (5.2 Mb). In established lines, CRISPR-Cas9 nuclease induces frequent terminal chromosome 11p truncations and rare copy-neutral LOH. In primary hematopoietic progenitor/stem cells, we detect 1.1% of clones (7/648) with acquired megabase LOH induced by CRISPR-Cas9. In-depth analysis by SNP-array reveals the presence of copy-neutral LOH. This leads to 11p15.5 partial uniparental disomy, comprising two Chr11p15.5 imprinting centers (H19/IGF2:IG-DMR/IC1 and KCNQ1OT1:TSS-DMR/IC2) and impacting H19 and IGF2 expression. While this genotoxicity is a safety concern for CRISPR clinical trials, it is also an opportunity to model copy-neutral-LOH for genetic diseases and cancers.

Spleen route accelerates engraftment of human hematopoietic stem cells.

Intravenous injections of human hematopoietic stem cells (hHSCs) is routinely used in clinic and for modeling hematopoiesis in mice. However, unspecific dilution in vascular system and non-hematopoietic organs challenges engraftment efficiency. Although spleen is capable of extra medullar hematopoiesis, its ability to support human HSC transplantation has never been evaluated. We demonstrate that intra-splenic injection results in high and sustained engraftment of hHSCs into immune-deficient mice, with higher chimerisms than with intravenous or intra-femoral injections. Our results support that spleen microenvironment provides a niche for HSCs amplification and offers a new route for efficient HSC transplantation.

[Renal cell carcinoma in candidates for renal transplantation and recipients of a kidney transplant: The French guidelines from CTAFU]. / Recommandations françaises du Comité de transplantation de l'association française d'urologie (CTAFU) : carcinome rénal sur reins natifs chez le patient transplanté rénal ou en attente de transplantation.

OBJECTIVE: To define guidelines for the management of renal cell carcinoma of the native kidney (NKRCC) in kidney transplant (KTx) recipients and renal cell carcinoma (RCC) in end-stage renal disease (ESRD) patients candidates for renal transplantation. METHOD: A review of the literature following a systematic approach (Medline) was conducted by the CTAFU to report renal cell carcinoma epidemiology, screening, diagnosis and management in KTx candidates and recipients. References were assessed according to a predefined process to propose recommendations with the corresponding levels of evidence. RESULTS: ESRD patients are at higher risk of RCC with a standardized incidence ratio of approximately 4,5 as compared with general population. NKRCC tumors occur in 1 to 3 % of KTx recipients with a 10 to 15-fold increased risk as compared with general population, especially in patients with acquired multicystic kidney disease. Most authors suggest yearly monitoring of the native kidneys using ultrasound imaging. Radical nephrectomy (either open or laparoscopic approach) is the preferred treatment of NKRCC in KTx recipients and RCC in ESRD. Surveillance in a valid option in small or cystic renal masses. In the localized setting, change in immunosuppressive therapy is not recommended besides perioperative avoidance of mTOR inhibitor to limit morbidity. CTAFU does not recommend a mandatory waiting time after nephrectomy for RCC in ESRD patients candidates for renal tranplantation when tumor stage

[Urothelial carcinoma in kidney transplant recipients and candidates: The French guidelines from CTAFU]. / Recommandations françaises du Comité de transplantation de l'association française d'urologie (CTAFU) : carcinome urothélial chez le patient transplanté rénal et le candidat à la transplantation rénale.

OBJECTIVE: To propose surgical recommendations for urothelial carcinoma management in kidney transplant recipients and candidates. METHOD: A review of the literature (Medline) following a systematic approcah was conducted by the CTAFU regarding the epidemiology, screening, diagnosis and treatment of urothelial carcinoma in kidney transplant recipients and candidates for renal transplantation. References were assessed according to a predefined process to propose recommendations with levels of evidence. RESULTS: Urothelial carcinomas occur in the renal transplant recipient population with a 3-fold increased incidence as compared with general population. While major risk factors for urothelial carcinomas are similar to those in the general population, aristolochic acid nephropathy and BK virus infection are more frequent risk factors in renal transplant recipients. As compared with general population, NMIBC in the renal transplant recipients are associated with earlier and higher recurrence rate. The safety and efficacy of adjuvant intravesical therapies have been reported in retrospective series. Treatment for localized MIBC in renal transplant recipients is based on radical cystectomy. In the candidate for a kidney transplant with a history of urothelial tumor, it is imperative to perform follow-up cystoscopies according to the recommended frequency, depending on the risk of recurrence and progression of NMIBC and to maintain this follow-up at least every six months up to transplantation whatever the level of risk of recurrence and progression. Based on current data, the present recommendations propose guidelines for waiting period before active wait-listing renal transplant candidates with a history of urothelial carcinoma. CONCLUSION: The french recommendations from CTAFU should contribute to improve the management of urothelial carcinoma in renal transplant patients and renal transplant candidates by integrating both oncologic objectives and access to transplantation.

[Acute renal failure of the donor in encephalic death: A real contraindication to kidney transplantation?] / L'insuffisance rénale aiguë du donneur en mort encéphalique : une réelle contre-indication à la transplantation rénale ?

INTRODUCTION: The shortage of kidney transplants encourages the expansion of the limits of eligibility criteria for donation. Many donors who are brain dead display acute renal failure at the time of death; is this a real contraindication to harvesting? The aim of this study was to assess kidney graft survival from donors after brain death with confirmed acute renal failure, with or without anuria previous donation. MATERIALS AND METHODS: All of the transplants performed in two university hospitals between 2010 and 2017 were analyzed retrospectively. All patients who underwent single kidney transplant from a brain-dead donor with acute renal failure (ARF) were included in this study. ARI was defined here by a decrease over 50 % of glomerular filtration rate (GFR) to a threshold below 45mL/min/1.73 m2 at the time of kidney procurement. Kidney graft survival, incidence of delayed graft function (DGF) and the GFR at 12 months were analyzed. Analysis of kidney transplant survival based on pre-implantation biopsies was additionally done. RESULTS: One hundred and sixty four patients were transplanted with a kidney from donor with ARF during the selected period. At the admission in ICU the average GFR was 67,7±19mL/min/1,73m2. At the time of donation, the average age of donors was 56.4±17.7 years, the GFR was 33.7±8.0mL/min/1.73 m2 16 % of donors were anuric. Cold ischemia time (CIT) was 16.8±5.0hours. The average age of recipients was 55.6±14.1 years. 81 % of the cases were primary transplants. Graft function took place within 7.8±9.4 days after transplantation. There were two non-primary functions (PNF). One hundred and fifty two patients (93 %) had a functional graft at 12 months. The mean GFR at 12 months was 46.8±20.1mL/min/1.73 m2 and 122 patients (73 %) had a GFR greater than 30mL/min/1.73 m2. Seventy-one percent of preimplantation biopsies revealed acute tubular necrosis (ATU); no cortical necrosis was observed. Survival of theses grafts was 85 %, comparable to the total population of study (P=0,21) CONCLUSION: The acute renal failure of the brain-dead donor should not alone be systematically a contraindication to harvesting and kidney transplantation.

The PINK1 kinase-driven ubiquitin ligase Parkin promotes mitochondrial protein import through the presequence pathway in living cells.

Most of over a thousand mitochondrial proteins are encoded by nuclear genes and must be imported from the cytosol. Little is known about the cytosolic events regulating mitochondrial protein import, partly due to the lack of appropriate tools for its assessment in living cells. We engineered an inducible biosensor for monitoring the main presequence-mediated import pathway with a quantitative, luminescence-based readout. This tool was used to explore the regulation of mitochondrial import by the PINK1 kinase-driven Parkin ubiquitin ligase, which is dysfunctional in autosomal recessive Parkinson's disease. We show that mitochondrial import was stimulated by Parkin, but not by disease-causing Parkin variants. This effect was dependent on Parkin activation by PINK1 and accompanied by an increase in the abundance of K11 ubiquitin chains on mitochondria and by ubiquitylation of subunits of the translocase of outer mitochondrial membrane. Mitochondrial import efficiency was abnormally low in cells from patients with PINK1- and PARK2-linked Parkinson's disease and was restored by phosphomimetic ubiquitin in cells with residual Parkin activity. Altogether, these findings uncover a role of ubiquitylation in mitochondrial import regulation and suggest that loss of this regulatory loop may underlie the pathophysiology of Parkinson's disease, providing novel opportunities for therapeutic intervention.

Pierre Richet (1904-1983), fighting onchocerciasis and totalitarism.

While Eugène Jamot's name is associated with the combat against sleeping sickness, Pierre Richet is permanently linked to the battle against river blindness, which he first reported in 1936 in two neighboring households in Garango (Burkina Faso). Onchocerciasis remained a continuous interest, through his last article "The OCCGE and Onchocerciasis", written in 1983. Nonetheless over the course of these five decades, Richet's trajectory was far from that of a specialist dedicating his life to a single disease. After a decade essentially spent fighting trypanosomiasis, came a decade of war in which the specialist in endemism joined the Free French Army and put his organizational know-how at General Lerclerc's disposal, from Morocco to Indochina, via Germany. On his return to Africa in 1953, he extended the principle of mobile teams to the other major endemic diseases accessible to treatment and to vaccines. Richet organized first the combat against leprosy and launched vaccination programs. In 1955, he returned to the battle against onchocerciasis and deployed the first large-scale insecticide program in Chad. The intermediate term failure of this prototype fermented his scientific, interdisciplinary, and organizational thought, which flourished at Bobo-Dioulasso. At the dawn of the independence of French-speaking African countries, and against the political tides of the time, he obtained in 1960 the creation of a supranational organization, the OCCGE, common to 8 countries of West Africa, and he headed it for a decade. Drawing lessons from the past and in the absence of effective pharmaceutical treatment, Richet the physician played the entomological card with one hand, with technical support from Orstom (IRD); this detailed work enabled the development of a strategy. With the other hand, he played the multilateral card, which led in 1974 to the launching of the extraordinary Onchocerciasis Control Program (OCP). If it is Jamot who awakened Africa, Richet is the person who restored its view but also millions of hectares of cultivable land.

Neglected tropical diseases (NTD): French-speaking researchers-fighters call for an integrated approach to diagnosis.

The French-speaking Network for Neglected Tropical Diseases (RFMTN), created under the aegis of Aviesan in April, 2016, has among its 5 objectives, those to promote interactions between the French-speaking institutions who are members, to develop collaborative programs making it possible to respond to requests for proposals and to advocate effectively to political bodies and funders. To mark the milestone of its first two years of existence, it held a plenary conference in Montpellier (France) on October 22 and 23, 2018, at which experts from numerous African, French and international scientific institutions participated very actively. This article presents the essence of the debates.

Robot-assisted renal transplantation using the retroperitoneal approach (RART) with more than one year follow up: Description of the technique and results.

OBJECTIVES: To describe the technique and report our first experience of robotic-assisted renal transplantation (RART) with more than one year follow up. PATIENTS AND METHODS: In our center the first case of RART was realized in October 2013 with a cadaveric graft. We used the combined extra- and intraperitoneal robot assisted laparoscopic route with extraperitoneal positioning of the graft and intraperitoneal transplantation. The patient was placed in the supine position with arms along the body; the robot came from the right inferior part of the patient. Access to the retroperitoneal space was obtained using an Alexis trocar that permitted the insertion of the kidney with ice without losing the pneumoperitoneum. Ports included a 12-mm camera port (placed under the ombilicus), two 8-mm robotic ports (placed 6cms laterally from the previous port) and a 12-mm assistant port (placed between the upper port and the ombilic). All the pre-, per- and postoperative data were prospectively included in a database. We report the results of the initial experience of RART, performed with more than one year follow-up. RESULTS: This technique is the first described using the retroperitoneal approach that is the routine approach for conventional open renal transplantation. This approach permitted to perform excellent arterial, veinous and ureteral anastomosis. Eight cases of RART were conducted between October 2013 and November 2015 (five men and three women). The average age was 58 years (range 39-75years). The average body mass index was 28 (range 22-38). Five patients had history of abdominal surgery and were dialyzed for 30 months on average (range 3-63months). Three left and five right cadavers kidneys were transplanted in the right iliac fossa. The mean graft size was 109mm (range 90-130). The mean length of the incision for insertion of the graft was 60 mms (40-100mms). Mean warm ischemia time was 63minutes (range 46-84). The total operative time was 200minutes (149-245). No patient was transfused during surgery and two were transfused postoperatively. Median length of hospital stay was 14 days (range 10-30 days). Only one patient needed postoperative morphine, the pain visual analogic scale 12hours postoperatively was 2 (0-5). Mean serum creatinine at seven days, at three months and at one year was 400 (98-639micromol/L), 151 (80-235micromol/L) and 129 (86-194micromol/L) respectively. At one year follow-up, no patient had a wound infection or incisional hernia. One patient was re-operated for ureteral anastomosis stricture. CONCLUSION: The retroperitoneal approach for RART permits the kidney to be cooled and a direct access to the iliac vessels and bladder. This initial series with more than a year of post-monitoring RART shows promising results despite some initial technical difficulties. The procedure can still be improved and hoped to see an improvement in the results. A comparison to the results of the conventional route is necessary before diffusing the robot-assisted technique. LEVEL OF PROOF: 3.

Management of renal transplant urolithiasis: a multicentre study by the French Urology Association Transplantation Committee.

PURPOSE: Urolithiasis is rare among renal transplant recipients and its management has not been clearly defined. METHODS: This multicentre retrospective study was organised by the Comité de Transplantation de l'Association Française d'Urologie (French Urology Association transplantation committee). Statistical analysis was performed with SPSS 19 software. RESULTS: Ninety-five patients were included in this study. Renal transplant urolithiasis was an incidental finding in 55% of cases, mostly on a routine follow-up ultrasound examination. One half of symptomatic stones were due to urinary tract infection and the other half were due to an episode of acute renal failure. The initial management following diagnosis of urolithiasis was double J stenting (27%), nephrostomy tube placement (21%), or watchful waiting (52%). Definitive management consisted of: watchful waiting (48%), extracorporeal lithotripsy (13%), rigid or flexible ureteroscopy (26%), percutaneous nephrolithotomy (11%) and surgical pyelotomy (2%). All transplants remained functional following treatment of the stone. The main limitation is the retrospective design. CONCLUSIONS: The incidence of lithiasis could be higher in kidney transplanted patients due to a possible anatomical or metabolical abnormalities. The therapeutic management of renal transplant urolithiasis appears to be comparable to that of native kidney urolithiasis.

[Impact of learning curve in renal transplantation]. / Impact de la courbe d'apprentissage dans la transplantation rénale.

OBJECTIVES: Renal transplantation is performed only in university hospital centres, in accredited transplanting centres. The aim of this study is to analyse the learning curve of this operation and its impact on the graft survival. PATIENTS-METHODS: Monocentric retrospective study in which 3 groups have been defined: Juniors 1, Juniors 2 and Seniors corresponding respectively to the first thirty transplantations and to the last thirty transplantations of 5 clinical leaders, and 30 transplantation graft of referent seniors. Data have been registered in a database. Operation times, lukewarm ischemic times and postoperative complications have been compared within the 3 groups. RESULTS: A clear difference of operation time has been noted within the 3 groups with an average time of 202 minutes for Juniors 1, 173 minutes for Juniors 2 and 140 minutes for Seniors (P<0.0001). Likewise, concerning lukewarm ischemic time and vascular anastomosis time respectively with an average time of 72, 59 and 40 min (P<0.0001). Vascular complications occurred in 20% of cases in Juniors 1, 44.3% of cases in Juniors 2 and 17% of cases in Seniors (P=0.65). There were no significant differences of survival without urinary complications: 20% of complications for Juniors 1, 10% for Juniors 2 and 17% for Seniors (P=0.63). Similarly results have been obtained with analysing complications following Clavien's order. CONCLUSION: This study reveals that renal transplantations operated by young surgeons require longer operation and lukeward ischemic time but without significant repercussions on the surgical complication rate and the global survival. This stresses on the importance of surgical training during medicine internship.