Human liver stem cells and derived products in experimental models of liver ischemia reperfusion injury and of liver isolated normothermic perfusion.

Ischemia reperfusion injury (IRI) is an antigen-independent inflammatory event that affects several clinical settings, including surgical procedures such as liver resection and liver transplantation. IRI is still a major concern in the transplantation setting, causing up to 10% of early graft failure and leading to a higher incidence of acute and chronic rejection. IRI is initiated by Kuppfer cells and hepatocytes through a massive production of reactive oxygen species (ROS) during the ischemic phase and, in a major degree, during the post-reperfusion phase. ROS directly damage hepatocytes and endothelial cells and promote the recruiment of neutrophils and T-cells, starting an inflammatory cascade that triggers apoptosis and necrosis. Human Liver Stem Cells (HLSC) have been identified as a population of pluripotent resident liver cells able to express markers characteristic of the mesenchymal lineage (CD73, CD90, CD29, CD44) together with hepatic markers (alpha-fetoprotein, cytokeratin 18, cytokerain 8 and albumin), suggesting a partial hepatic commitment. HLSC share self-renewal properties with mesenchymal stem cells and can actively take part to tissue remodeling and liver regeneration. We found that HLSC are able to localize within the injured tissue and promote liver regeneration in a murine model of fulminant liver failure and to generate a functional “humanized liver-like tissue” when injected in rat acellular liver scaffolds. Growing evidence suggests that the biological effects of stem cells on neighboring cells are mediated by paracrine mechanisms including the release of extracellular vesicles (EV). EV are an heterogeneous population of cell-secreted vesicles originating from the endosomal compartment or from direct budding of plasma membrane that are able to modify the phenotype and function of neighboring cells. The regenerative effects of EV are well documented and ascribed to a horizontal transfer of proteins, lipids and, above all, specific subsets of mRNA and miRNA. In a rat model of 70% hepatectomy, animals treated with Human Liver Stem Cells-derived Extracellular Vesicles (HLSC-EV) revealed a significant reduction of liver injury and higher regeneration rate of the remnant liver after surgery . The effect of HLSC-EV was investigated on two different experimental models: First Project We set up a short-duration model of ex vivo isolated rat liver Normothermic Machine Perfusion (NMP) in which oxygen delivery was kept suboptimal through a low hemoglobin content in the perfusate. In this model, we investigated whether adding HLSC-EV to the circuit could result in i) their rapid uptake by the liver, and ii) an appreciable reduction of the hypoxic tissue injury. Second Project An in-vivo model of IRI was set up in mice. The aim of this study was to investigate the effects of systemic administration of HLSC-EV on tissue injury after partial clamping of the hepatic hilum (70%)

Effective pointing of the ASTRI-Horn telescope using the Cherenkov camera with the Variance method

Cherenkov telescope cameras are not suitable to perform astrometrical pointing calibration since they are not designed to produce images of the sky, but rather to detect nanosecond atmospheric flashes due to very high-energy cosmic radiation. Indeed, these instruments show only a moderate angular resolution (fractions of degrees) and are almost blind to the steady or slow-varying optical signal of starlight. For this reason, auxiliary optical instruments are typically adopted to calibrate the telescope pointing. However, secondary instruments are possible sources of systematic errors. Furthermore, the Cherenkov camera is the only one framing exactly the portion of the sky under study, and hence its exploitation for pointing calibration purposes would be desirable. In this contribution, we present a procedure to assess the pointing accuracy of the ASTRI-Horn telescope by means of its innovative Cherenkov camera. This instrument is endowed with a statistical method, the so-called Variance method, implemented in the logic board and able to provide images of the night sky background light as ancillary output. Taking into account the convolution between the optical point spread function and the pixel distribution, Variance images can be used to evaluate the position of stars with sub-pixel precision. In addition, the rotation of the field of view during observations can be exploited to verify the alignment of the Cherenkov camera with the optical axis of the telescope, with a precision of a few arcminutes, as upper limit. This information is essential to evaluate the effective pointing of the telescope, enhancing the scientific accuracy of the system.Comment: 7 pages, 5 figures, Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, German

The future direction of imaging in prostate cancer: MRI with or without contrast injection

Background: Multiparametric MRI (mpMRI) is the "state of the art" management tool for patients with prostate cancer (PCa) suspicion. The role of non-contrast MRI is investigated to move toward a more personalized, less invasive, and highly cost-effective PCa diagnostic workup. Objective: To perform a non-systematic review of the existing literature to highlight strength and flaws of performing non-contrast MRI, and to provide a critical overview of the international scientific production on the topic. Materials and methods: Online databases (Medline, PubMed, and Web of Science) were searched for original articles, systematic review and meta-analysis, and expert opinion papers. Results: Several investigations have shown comparable diagnostic accuracy of biparametric (bpMRI) and mpMRI for the detection of PCa. The advantage of abandoning contrast-enhanced sequences improves operational logistics, lowering costs, acquisition time, and side effects. The main limitations of bpMRI are that most studies which compared the non-contrast and contrast MRI come from centers with high expertise that might not be reproducible in the general community setting; besides, reduced protocols might be insufficient for estimation of the intra- and extra-prostatic extension and regional disease. The mentioned observations suggest that low quality mpMRI for the general population, might represent the main shortage to overcome. Discussion: Non-contrast MRI future trends are likely represented by PCa screening and the application of artificial intelligence (AI) tools. PCa screening is still a controversial topic and bpMRI, and has become one of the most promising diagnostic applications, as it is a more sensitive test for PCa early detection, compared to serum PSA level test. Also, AI applications and radiomic have been the object of several studies investigating PCa detection using bpMRI, showing encouraging results. Conclusion: Today, the accessibility to MRI for early detection of PCa is a priority. Results from prospective, multicenter, multireader and paired validation studies are needed to provided evidence supporting its role in the clinical practice

Outcome of liver transplantation with grafts from brain-dead donors treated with dual hypothermic oxygenated machine perfusion, with particular reference to elderly donors

Prompted by the utilization of extended criteria donors, dual hypothermic oxygenated machine perfusion (D‐HOPE) was introduced in liver transplantation to improve preservation. When donors after neurological determination of death (DBD) are used, D‐HOPE effect on graft outcomes is unclear. To assess D‐HOPE value in this setting and to identify ideal scenarios for its use, data on primary adult liver transplant recipients from January 2014 to April 2021 were analyzed using inverse probability of treatment weighting, comparing outcomes of D‐HOPE‐treated grafts (n = 121) with those preserved by static cold storage (n = 723). End‐ischemic D‐HOPE was systematically applied since November 2017 based on donor and recipient characteristics and transplant logistics. D‐HOPE use was associated with a significant reduction of early allograft failure (OR: 0.24; 0.83; p = .024), grade ≥3 complications (OR: 0.57; p = .046), comprehensive complication index (−7.20 points; p = .003), and improved patient and graft survival. These results were confirmed in the subset of elderly donors (>75‐year‐old). Although D‐HOPE did not reduce the incidence of biliary complications, its use was associated with a reduced severity of ischemic cholangiopathy. In conclusion, D‐HOPE improves postoperative outcomes and reduces early allograft loss in extended criteria DBD grafts

An 1H NMR study of the cytarabine degradation in clinical conditions to avoid drug waste, decrease therapy costs and improve patient compliance in acute leukemia

Cytarabine, the 4-amino-1-(β-D-arabinofuranosyl)-2(1H)-pyrimidinone, (ARA-C) is an antimetabolite cytidine analogue used worldwide as key drug in the management of leukaemia. As specified in the manufacturers' instructions, once the components-sterile water and cytarabine powder-are unpackaged and mixed, the solution begins to degrade after 6 hours at room temperature and 12 hours at 4°C. To evaluate how to avoid wasting the drug in short-term, low-dose treatment regimens, the reconstituted samples, stored at 25°C and 4°C, were analyzed every day of the test week by reversed-phase HPLC and high-field NMR spectroscopy. All the samples remained unchanged for the entire week, which corresponds to the time required to administer the entire commercial drug package during low-dose therapeutic regimens. The drug solution was stored in a glass container at 4°C in an ordinary freezer and drawn with sterile plastic syringes; during this period, no bacterial or fungal contamination was observed. Our findings show that an cytarabine solution prepared and stored in the original vials retains its efficacy and safety and can, therefore, be divided into small doses to be administered over more days, thus avoiding unnecessary expensive and harmful waste of the drug preparation. Moreover, patients who require daily administration of the drug could undergo the infusion at home without need to go to hospital. The stability of the aliquots would help decrease hospitalization costs