Granulocyte macrophage colony stimulating factor improves mucosal repair in a mouse model of acute colitis (P278)

Background and Aims: Granulocyte-macrophage colonystimulating factor (GM-CSF), a cytokine modulating the number and function of innate immune cells, has been shown to provide symptomatic benefit in some patients with Crohn's disease (CD). Since, it becomes widely appreciated that a timely and spatially regulated action of innate immune cells is critical for tissue regeneration, we tested whether GM-CSF therapy may favours intestinal mucosal repair in the acute mouse model of dextran sulfate sodium (DSS)-induced colitis. Methods: Mice treated with GM-CSF or saline were exposed for 7 days to DSS to induce colitis. On day 5, 7 and 10, mice were subjected to colonoscopy or sacrificed for evaluation of inflammatory reaction and mucosal healing. Results: GM-CSF therapy prevented body weight loss, diarrhea, dampened inflammatory reactions and ameliorated mucosal damages. Mucosal repair improvement in GM-CSF-treated mice was observed from day 7 on both by colonoscopy (ulceration score 1.2}0.3 (GM-CSF-treated) vs 3.1}0.5 (untreated), p = 0.01) and histological analysis (percentage of reepithelialized ulcers 55%}4% (GM-CSF-treated) vs 18%}13% (untreated), p = 0.01). GM-CSF therapy can still improve the colitis when hematopoietic, but not non-hematopoietic cells, are responsive to GM-CSF, as shown in WT→GM-CSFRKO chimeras. Lastly, we observed that GM-CSF-induced promotion of wound healing is associated with a modification of the cellular composition of DSS-induced colonic inflammatory infiltrate, characterized by the reduction of neutrophil numbers and early accumulation of CD11b+Gr1lo myeloid cells. Conclusion: Our study shows that GM-CSF therapy accelerates the complex program leading to tissue repair during acute colitis and suggests that GM-CSF promotion of mucosal repair might contribute to the symptomatic benefits of GM-CSF therapy observed in some CD patients.

RDM1, a novel RNA recognition motif (RRM)-containing protein involved in the cell response to cisplatin in vertebrates.

A variety of cellular proteins has the ability to recognize DNA lesions induced by the anti-cancer drug cisplatin, with diverse consequences on their repair and on the therapeutic effectiveness of this drug. We report a novel gene involved in the cell response to cisplatin in vertebrates. The RDM1 gene (for RAD52 Motif 1) was identified while searching databases for sequences showing similarities to RAD52, a protein involved in homologous recombination and DNA double-strand break repair. Ablation of RDM1 in the chicken B cell line DT40 led to a more than 3-fold increase in sensitivity to cisplatin. However, RDM1-/- cells were not hypersensitive to DNA damages caused by ionizing radiation, UV irradiation, or the alkylating agent methylmethane sulfonate. The RDM1 protein displays a nucleic acid binding domain of the RNA recognition motif (RRM) type. By using gel-shift assays and electron microscopy, we show that purified, recombinant chicken RDM1 protein interacts with single-stranded DNA as well as double-stranded DNA, on which it assembles filament-like structures. Notably, RDM1 recognizes DNA distortions induced by cisplatin-DNA adducts in vitro. Finally, human RDM1 transcripts are abundant in the testis, suggesting a possible role during spermatogenesis.

Corrigendum : Novel loci affecting iron homeostasis and their effects in individuals at risk for hemochromatosis

Absorption, transport and storage of iron are tightly regulated, as expected for an element, which is both essential and potentially toxic. Iron deficiency is the leading cause of anaemia, and it also compromises immune function and cognitive development. Iron overload damages the liver and other organs in hereditary hemochromatosis, and in thalassaemia patients with both transfusion and non-transfusionrelated iron accumulation. Excess iron has harmful effects in chronic liver diseases caused by excessive alcohol, obesity or viruses. There is evidence for involvement of iron in neurodegenerative diseases and in Type 2 diabetes. Variation in transferrin saturation, a biomarker of iron status, has been associated with mortality in patients with diabetes and in the general population13. All these associations between iron and either clinical disease or pathological processes make it important to understand the causes of variation in iron status. Importantly, information on genetic causes of variation can be used in Mendelian randomization studies to test whether variation in iron status is a cause or consequence of disease. We have used biomarkers of iron status (serum iron, transferrin, transferrin saturation and ferritin), which are commonly used clinically and readily measurable in thousands of individuals, and carried out a meta-analysis of human genomewide association study (GWAS) data from 11 discovery and eight replication cohorts. Our aims were to identify additional loci affecting markers of iron status in the general population and to relate the significant loci to information on gene expression to identify relevant genes. We also made an initial assessment of whether any such loci affect iron status in HFE C282Y homozygotes, who are at genetic risk of HFE-related iron overload (hereditary hemochromatosis type 1, OMIM #235200)

Antihypertensive Combination Treatment: State of the Art.

An adequate control of blood pressure is essential to reduce the risk of target organ damages and cardiovascular events in patients with hypertension. Yet, it is well recognized that a substantial proportion of treated patients remain hypertensive despite treatment. Several reasons have been evoked to explain why so many patients are not adequately controlled. Among them, medical inertia, a poor long-term adherence, and the need to prescribe several antihypertensive drugs to reach the target blood pressure have been identified as major limitations to the success of antihypertensive therapy. In this context, the use of single-pill combinations (SPC) containing two or three drugs in one pill has an important role in reducing the impact of some of these issues. Indeed, the use of SPC enables to reduce the pill burden and to improve the treatment efficacy without increasing the incidence of side effects. However, besides their major advantages, SPC have also some limitations such as a possible lack of flexibility or a higher cost. The purpose of this review is to discuss the place of SPC in the actual management of hypertension. The active development of new single-pill combinations in last years can be considered as a significant improvement in the physicians' capacity to treat hypertension effectively.

Apical closure device for transapical valve procedures?.

OBJECTIVES: Transapical transcatheter valve procedures are performed through a left minithoracotomy and require apical sutures to seal the apical access site. The use of large-calibre devices compromises any attempt to fully perform the procedure with a thoracoscopic approach or percutaneously. We report our preliminary experience in animals with a new sutureless self-expandable apical occluder, engineered to perform transapical access site closure in a minimally invasive setting with large-size introducer sheaths. METHODS: The apical occluder with extendable waist was implanted in six young pigs during an acute animal study. Under general anaesthesia, animals (mean weight: 62 ± 8 kg) received full heparinization (heparin: 100 UI/kg; activated clotting time above 250 s). Through a median sternotomy, a 21-Fr Certitude? introducer sheath (outer diameter: 25 Fr) was placed over the wire into the cardiac apex. The delivery catheter carrying the constrained apical plug was inserted into the sheath and deployed under fluoroscopic control, whereas the Certitude? was retrieved. After protamine infusion, we observed and recorded the 1-h bleeding with standard haemodynamic parameters. Animals were sacrificed, and hearts analysed. RESULTS: Six apical closure devices were successfully introduced and deployed in six pig hearts through large-size apical sheaths at first attempt. In all animals, the plugs guaranteed immediate apical sealing and traces of blood were collected in the pericardium during the 1-h observational period (mean of 16 ± 3.4 ml of blood loss per animal). Haemodynamic parameters remained stable during the entire study period and no plug dislodgement was detected with normal systemic blood pressure (mean arterial mean blood pressure: 65 ± 7 mmHg). Post-mortem analysis confirmed the full deployment and good fixation of all plugs, without macroscopic damages to the surrounding myocardium. CONCLUSIONS: This sutureless self-expandable apical occluder is a simple device capable of sealing large-size apical access sites (20-35 Fr) in an acute animal study. This approach is a step further towards less invasive transapical valve procedures in the clinical setting, and further animal tests will be performed to confirm the long-term efficacy and safety of this device.

Aldosterone effects on glomerular structure and function.

OBJECTIVE: Experimental evidence suggests that aldosterone directly contributes to organ damage by promoting cell growth, fibrosis, and inflammation. Based on these premises, this work aimed to assess the glomerular effects of aldosterone, alone and in combination with salt. METHODS: After undergoing uninephrectomy, 75 rats were allocated to five groups: control, salt diet, aldosterone, aldosterone + salt diet, aldosterone + salt diet and eplerenone, and they were all studied for four weeks. We focused on glomerular structural, functional, and molecular changes, including slit diaphragm components, local renin-angiotensin system activation, as well as pro-oxidative and profibrotic changes. RESULTS: Aldosterone significantly increased systolic blood pressure, led to glomerular hypertrophy, mesangial expansion, and it significantly increased the glomerular permeability to albumin and the albumin excretion rate, indicating the presence of glomerular damage. These effects were worsened by adding salt to aldosterone, while they were reduced by eplerenone. Aldosterone-induced glomerular damage was associated with glomerular angiotensin-converting enzyme (ACE) 2 downregulation, with ACE/ACE2 ratio increase, ANP decrease, as well as with glomerular pro-oxidative and profibrotic changes. CONCLUSIONS: Aldosterone damages not only the structure but also the function of the glomerulus. ACE/ACE2 upregulation, ACE2 and ANP downregulation, and pro-oxidative and profibrotic changes are possible mechanisms accounting for aldosterone-induced glomerular injury.

An interactive web-GIS tool for risk analysis: a case study in the Fella River basin, Italy

This paper presents a prototype of an interactive web-GIS tool for risk analysis of natural hazards, in particular for floods and landslides, based on open-source geospatial software and technologies. The aim of the presented tool is to assist the experts (risk managers) in analysing the impacts and consequences of a certain hazard event in a considered region, providing an essential input to the decision-making process in the selection of risk management strategies by responsible authorities and decision makers. This tool is based on the Boundless (OpenGeo Suite) framework and its client-side environment for prototype development, and it is one of the main modules of a web-based collaborative decision support platform in risk management. Within this platform, the users can import necessary maps and information to analyse areas at risk. Based on provided information and parameters, loss scenarios (amount of damages and number of fatalities) of a hazard event are generated on the fly and visualized interactively within the web-GIS interface of the platform. The annualized risk is calculated based on the combination of resultant loss scenarios with different return periods of the hazard event. The application of this developed prototype is demonstrated using a regional data set from one of the case study sites, Fella River of northeastern Italy, of the Marie Curie ITN CHANGES project.

Characterization of a MAF1 knockout mouse model

L'ARN polymérase 3 transcrit un petit groupe de gènes fortement exprimés et impliqués dans plusieurs mécanismes moléculaires. Les ARNs de transfert ou ARNt représentent plus ou moins la moitié du transcriptome de l'ARN polymérase 3. Ils sont directement impliqués dans la traduction des protéines en agissant comme transporteurs d'acides aminés qui sont incorporés à la chaîne naissante de polypeptides. Chez des levures cultivées dans un milieu jusqu'à épuisement des nutriments, Maf1 réprime la transcription par l'ARN polymérase 3, favorisant ainsi l'économie énergétique cellulaire. Dans un modèle de cellules de mammifères, MAF1 réprime aussi la transcription de l'ARN polymérase 3 dans des conditions de stress, cependant il n'existe aucune donnée quant à son rôle chez un mammifère vivant. Pendant mon doctorat, j'ai utilisé une souris délétée pour le gène Maf1 afin de connaître les effets de ce gène chez un mammifère. Etonnamment, la souris Maf1-­‐/-­‐ est résistante à l'obésité même si celle-­‐ci est nourrie avec une nourriture riche en matières grasses. Des études moléculaires et de métabolomiques ont montré qu'il existe des cycles futiles de production et dégradation des lipides et des ARNt, ce qui entraîne une augmentation de la dépense énergique et favorise la résistance à l'obésité. En plus de la caractérisation de la souris Maf1-­‐/-­‐, pendant ma thèse j'ai également développé une méthode afin de normaliser les données de ChIP-­‐sequencing. Cette méthode est fondée sur l'utilisation d'un contrôle interne, représenté ici par l'ajout d'une quantité fixe de chromatine provenant d'un organisme différent de celui étudié. La méthode a amélioré considérablement la reproductibilité des valeurs entre réplicas biologiques. Elle a aussi révélé des différences entre échantillons issus de conditions différentes. Une occupation supérieure de l'ARN polymérase 3 sur les gènes Pol 3 chez les souris Maf1 KO entraîne une augmentation du niveau de précurseurs d'ARNt, ayant pour effet probable la saturation de la machinerie de maturation des ARNt. En effet, chez les souris Maf1 KO, le pourcentage d'ARNt modifiés est plus faible que chez les souris type sauvage. Ce déséquilibre entre le niveau de précurseurs et d'ARNt matures entraîne une diminution de la traduction protéique. Ces résultats ont permis d'identifier de nouvelles fonctions pour la protéine MAF1, comme étant une protéine régulatrice à la fois de la transcription mais aussi de la traduction et en étant un cible potentielle au traitement à l'obésité. -- RNA polymerase III (Pol 3) transcribes a small set of highly expressed genes involved in different molecular mechanisms. tRNAs account for almost half of the Pol 3 transcriptome and are involved in translation, bringing a new amino into the nascent polypeptide chain. In yeast, under nutrient deprivation, Maf1 acts for cell energetic economy by repressing Pol 3 transcription. In mammalian cells, MAF1 also represses Pol 3 activity under conditions of serum deprivation or DNA damages but nothing is known about its role in a mammalian organism. During my thesis studies, I used a Maf1 KO mouse model to characterize the effects of Maf1 deletion in a living animal. Surprisingly, the MAF1 KO mouse developed an unexpected phenotype, being resistant to high fat diet-­‐induced obesity and displaying an extended lifespan. Molecular and metabolomics characterizations revealed futile cycles of lipids and tRNAs, which are produced and immediately degraded, which increases energy consumption in the Maf1 KO mouse and probably explains in part the protection to obesity. Additionally to the mouse characterization, I also developed a method to normalize ChIP-­‐seq data, based on the addition of a foreign chromatin to be used as an internal control. The method improved reproducibility between replicates and revealed differences of Pol 3 occupancy between WT and Maf1 KO samples that were not seen without normalization to the internal control. I then established that increased Pol 3 occupancy in the Maf1 KO mouse liver was associated with increased levels of tRNA precursor but not of mature tRNAs, the effective molecules involved in translation. The overproduction of precursor tRNAs associated with the deletion of Maf1 apparently overwhelms the tRNA processing machinery as the Maf1 KO mice have lower levels of fully modified tRNAs. This maturation defect directly impacts on translation efficiency as polysomic fractions and newly synthetized protein levels were reduced in the liver of the Maf1 KO mouse. Altogether, these results indicate new functions for MAF1, a regulator of both transcription and translation as well as a potential target for obesity treatment.

Apnea-like suppression of respiratory motion: First evaluation in radiotherapy.

BACKGROUND AND PURPOSE: Compensation for respiratory motion is needed while administering radiotherapy (RT) to tumors that are moving with respiration to reduce the amount of irradiated normal tissues and potentially decrease radiation-induced collateral damages. The purpose of this study was to test a new ventilation system designed to induce apnea-like suppression of respiratory motion and allow long enough breath hold durations to deliver complex RT. MATERIAL AND METHODS: The High Frequency Percussive Ventilation system was initially tested in a series of 10 volunteers and found to be well tolerated, allowing a median breath hold duration of 11.6min (range 3.9-16.5min). An evaluation of this system was subsequently performed in 4 patients eligible for adjuvant breast 3D conformal RT, for lung stereotactic body RT (SBRT), lung volumetric modulated arc therapy (VMAT), and VMAT for palliative pleural metastases. RESULTS: When compared to free breathing (FB) and maximal inspiration (MI) gating, this Percussion Assisted RT (PART) offered favorable dose distribution profiles in 3 out of the 4 patients tested. PART was applied in these 3 patients with good tolerance, without breaks during the "beam on time period" throughout the overall courses of RT. The mean duration of the apnea-like breath hold that was necessary for delivering all the RT fractions was 7.61min (SD=2.3). CONCLUSIONS: This first clinical implementation of PART was found to be feasible, tolerable and offers new opportunities in the field of RT for suppressing respiratory motion.