Neonatal Hyperbilirubinemia: <i>in vivo</i> Characterization of Mechanisms of Bilirubin Neurotoxicity and Pharmacological Treatments

Neonatal jaundice or hyperbilirubinemia is the result of alterations in the bilirubin metabolism. Prolonged and uncontrolled high levels of unconjugated bilirubin lead to bilirubin-induced neurological dysfunction and, if untreated, eventually death by kernicterus. Severe hyperbilirubinemia results in the saturation of the bilirubin binding capacity of plasma albumin, with the consequent increase in the fraction of unconjugated bilirubin (UCB) not bound to albumin (free bilirubin, Bf) that, due to its lipophilicity, crosses the blood brain barrier accumulating in the brain and triggering the neuronal injury. In the developing central nervous system, a wide range of cellular functions are affected and the concerted disruption of their regulation results in cellular damage. Patients experiencing prolonged toxic bilirubin levels are characterized by a number of neurological deficits, such as abnormalities in motor, sensitive and cognitive functions. Despite intensive studies, several aspects of the mechanisms operating at the onset of the disease are still partially understood. To study severe neonatal hyperbilirubinemia and possible therapies, I took advantage of the Ugt1-/- mouse model previously generated in my laboratory. Homozygous mutant mice develop jaundice and accumulate bilirubin in the brain due to the lack of the Ugt1a1 enzyme. If untreated, mutant mice show neurological deficits leading to early neonatal lethality. The work performed in this Thesis explores three different aspects of bilirubin neurotoxicity: 1. The role of Bf in vivo by the administration of human serum albumin; 2. The events preceding death by a time-course analysis of mutant pups; 3. The investigation of the role of neuroinflammation by the administration of a neuroprotective and anti-inflammatory drug. The obtained results showed that increasing plasma bilirubin-binding capacity by albumin supplementation decreases bilirubin neurotoxicity. In fact, daily albumin administration avoided the accumulation of Bf in the brain by its mobilization from tissues to plasma, resulting in the complete rescue of bilirubin-induced brain impairment and lethality. Moreover, this study highlighted the reliability of Bf as the best marker to predict neurotoxicity risk. The time-course investigation of the events occurring in the cerebellum of Ugt1-/- pups leading to bilirubin-brain damage showed the prevalence of ER stress, oxidative stress and neuroinflammation at the onset of neonatal hyperbilirubinemia that, in turn, affected brain integrity by their concerted effect resulting in neurodegeneration. Finally, the administration of minocycline (MNC), an antibiotic with neuroprotective and anti-inflammatory properties, partially prevented lethality by hyperbilirubinemia and rescued animals by significantly reducing neurodegenerative and neuroinflammatory features that characterized the untreated Ugt1-/- mouse model. This study demonstrates the contribution of ER stress and inflammation in the onset of the disease, the relevance of these mechanisms during the attenuation of neurodegeneration by MNC administration, and that albumin supplementation is a potential therapeutic alternative to treat bilirubin neurotoxicity in acute cases in which prompt exchange transfusion is required

Pengembangan Perangkat Pembelajaran Flipped Classroom Pada Materi Getaran Harmonis

The aims of this research are to determine the validity of the product by experts and practitioners as well as to describe the attractiveness, the easiness and the expediency of the product. Development models used in this research is the ADDIE model which consists of five stages: analysis, design, development, implementation, and evaluation. The stage at this research explains only at the stage of development. The results obtained from expert validation test with an average score of 3.60 with the qualifying products is very valid, practitioners test results obtained an average score of 3.28 with very valid qualifying, and one by one test results of the product showed that the product was very attractive, very easy to use, and helpful. Penelitian ini bertujuan untuk mengetahui validitas produk oleh ahli dan praktisi serta untuk mendeskripsikan kemenarikan, kemudahan, dan kemanfaatan dari produk pengembangan. Model pengembangan yang digunakan dalam penelitian ini adalah model ADDIE yang terdiri dari lima tahapan, yaitu analisis, desain, pengembangan, implementasi, dan evaluasi. Pada penelitian ini, tahapan yang dilakukan hanya sampai pada tahap pengembangan. Hasil penelitian yang diperoleh dari uji validasi ahli yaitu rata-rata skor produk 3,60 dengan kualifikasi sangat valid, hasil uji praktisi diperoleh rata-rata skor 3,28 dengan kualifikasi sangat valid, dan hasil uji 1-1 menunjukkan bahwa produk memiliki kualitas sangat menarik, sangat mudah digunakan, dan bermanfaat

Albumin administration prevents neurological damage and death in a mouse model of severe neonatal hyperbilirubinemia

Therapies to prevent severe neonatal unconjugated hyperbilirubinemia and kernicterus are phototherapy and, in unresponsive cases, exchange transfusion, which has significant morbidity and mortality risks. Neurotoxicity is caused by the fraction of unconjugated bilirubin not bound to albumin (free bilirubin, Bf). Human serum albumin (HSA) administration was suggested to increase plasma bilirubin-binding capacity. However, its clinical use is infrequent due to difficulties to address its potential preventive and curative benefits, and to the absence of reliable markers to monitor bilirubin neurotoxicity risk. We used a genetic mouse model of unconjugated hyperbilirubinemia showing severe neurological impairment and neonatal lethality. We treated mutant pups with repeated HSA administration since birth, without phototherapy application. Daily intraperitoneal HSA administration completely rescued neurological damage and lethality, depending on dosage and administration frequency. Albumin infusion increased plasma bilirubin-binding capacity, mobilizing bilirubin from tissues to plasma. This resulted in reduced plasma Bf, forebrain and cerebellum bilirubin levels. We showed that, in our experimental model, Bf is the best marker to determine the risk of developing neurological damage. These results support the potential use of albumin administration in severe acute hyperbilirubinemia conditions to prevent or treat bilirubin neurotoxicity in situations in which exchange transfusion may be required.</p

A new laser device for ultra-rapid and sustainable aerosol sterilization

The current COVID-19 pandemic has highlighted the importance of aerosol-based transmission of human pathogens; this therefore calls for novel medical devices which are able to sterilize contaminated aerosols. Here we describe a new laser device able to sterilize droplets containing either viruses or bacteria. Using engineered viral particles, we determined the 10,600 nm wavelength as the most efficient and exploitable laser source to be manufactured in a commercial device. Given the lack of existing working models to reproduce a human aerosol containing living microbial particles, we developed a new system mimicking human droplet formation and preserving bacterial and viral viability. This evidenced the efficacy of 10,600 nm laser light to kill two aerosol transmitted human pathogens, Legionella pneumophila and SARS-CoV-2. The minimal exposure time of &lt;15 ms was required for the inactivation of over 99% pathogens in the aerosol; this is a key element in the design of a device that is safe and can be used in preventing inter-individual transmission. This represents a major advantage over existing devices, which mainly aim at either purifying incoming air by filters or sterilizing solid surfaces, which are not the major transmission routes for airborne communicable diseases

Genetic lineage tracing reveals poor angiogenic potential of cardiac endothelial cells.

Abstract Aims Cardiac ischaemia does not elicit an efficient angiogenic response. Indeed, lack of surgical revascularization upon myocardial infarction results in cardiomyocyte death, scarring, and loss of contractile function. Clinical trials aimed at inducing therapeutic revascularization through the delivery of pro-angiogenic molecules after cardiac ischaemia have invariably failed, suggesting that endothelial cells in the heart cannot mount an efficient angiogenic response. To understand why the heart is a poorly angiogenic environment, here we compare the angiogenic response of the cardiac and skeletal muscle using a lineage tracing approach to genetically label sprouting endothelial cells. Methods and results We observed that overexpression of the vascular endothelial growth factor in the skeletal muscle potently stimulated angiogenesis, resulting in the formation of a massive number of new capillaries and arterioles. In contrast, response to the same dose of the same factor in the heart was blunted and consisted in a modest increase in the number of new arterioles. By using Apelin-CreER mice to genetically label sprouting endothelial cells we observed that different pro-angiogenic stimuli activated Apelin expression in both muscle types to a similar extent, however, only in the skeletal muscle, these cells were able to sprout, form elongated vascular tubes activating Notch signalling, and became incorporated into arteries. In the heart, Apelin-positive cells transiently persisted and failed to give rise to new vessels. When we implanted cancer cells in different organs, the abortive angiogenic response in the heart resulted in a reduced expansion of the tumour mass. Conclusion Our genetic lineage tracing indicates that cardiac endothelial cells activate Apelin expression in response to pro-angiogenic stimuli but, different from those of the skeletal muscle, fail to proliferate and form mature and structured vessels. The poor angiogenic potential of the heart is associated with reduced tumour angiogenesis and growth of cancer cells

Author Correction: Mutant p53 sustains serine-glycine synthesis and essential amino acids intake promoting breast cancer growth

Reprogramming of amino acid metabolism, sustained by oncogenic signaling, is crucial for cancer cell survival under nutrient limitation. Here we discovered that missense mutant p53 oncoproteins stimulate de novo serine/glycine synthesis and essential amino acids intake, promoting breast cancer growth. Mechanistically, mutant p53, unlike the wild-type counterpart, induces the expression of serine-synthesis-pathway enzymes and L-type amino acid transporter 1 (LAT1)/CD98 heavy chain heterodimer. This effect is exacerbated by amino acid shortage, representing a mutant p53-dependent metabolic adaptive response. When cells suffer amino acids scarcity, mutant p53 protein is stabilized and induces metabolic alterations and an amino acid transcriptional program that sustain cancer cell proliferation. In patient-derived tumor organoids, pharmacological targeting of either serine-synthesis-pathway and LAT1-mediated transport synergizes with amino acid shortage in blunting mutant p53-dependent growth. These findings reveal vulnerabilities potentially exploitable for tackling breast tumors bearing missense TP53 mutation

Mutant p53 sustains serine-glycine synthesis and essential amino acids intake promoting breast cancer growth

Reprogramming of amino acid metabolism, sustained by oncogenic signaling, is crucial for cancer cell survival under nutrient limitation. Here we discovered that missense mutant p53 oncoproteins stimulate de novo serine/glycine synthesis and essential amino acids intake, promoting breast cancer growth. Mechanistically, mutant p53, unlike the wild-type counterpart, induces the expression of serine-synthesis-pathway enzymes and L-type amino acid transporter 1 (LAT1)/CD98 heavy chain heterodimer. This effect is exacerbated by amino acid shortage, representing a mutant p53-dependent metabolic adaptive response. When cells suffer amino acids scarcity, mutant p53 protein is stabilized and induces metabolic alterations and an amino acid transcriptional program that sustain cancer cell proliferation. In patient-derived tumor organoids, pharmacological targeting of either serine-synthesis-pathway and LAT1-mediated transport synergizes with amino acid shortage in blunting mutant p53-dependent growth. These findings reveal vulnerabilities potentially exploitable for tackling breast tumors bearing missense TP53 mutations.Mutant p53 induces serine/glycine synthesis and essential amino acids intake. Under amino acid restriction, mutant p53 is stabilized and activates a transcriptional program that sustains a metabolic adaptive response promoting breast cancer cells growt

Ischemic wound revascularization by the stromal vascular fraction relies on host-donor hybrid vessels

Nonhealing wounds place a significant burden on both quality of life of affected patients and health systems. Skin substitutes are applied to promote the closure of nonhealing wounds, although their efficacy is limited by inadequate vascularization. The stromal vascular fraction (SVF) from the adipose tissue is a promising therapy to overcome this limitation. Despite a few successful clinical trials, its incorporation in the clinical routine has been hampered by their inconsistent results. All these studies concluded by warranting pre-clinical work aimed at both characterizing the cell types composing the SVF and shedding light on their mechanism of action. Here, we established a model of nonhealing wound, in which we applied the SVF in combination with a clinical-grade skin substitute. We purified the SVF cells from transgenic animals to trace their fate after transplantation and observed that it gave rise to a mature vascular network composed of arteries, capillaries, veins, as well as lymphatics, structurally and functionally connected with the host circulation. Then we moved to a human-in-mouse model and confirmed that SVF-derived endothelial cells formed hybrid human-mouse vessels, that were stabilized by perivascular cells. Mechanistically, SVF-derived endothelial cells engrafted and expanded, directly contributing to the formation of new vessels, while a population of fibro-adipogenic progenitors stimulated the expansion of the host vasculature in a paracrine manner. These data have important clinical implications, as they provide a steppingstone toward the reproducible and effective adoption of the SVF as a standard care for nonhealing wounds

Towards standardization of echocardiography for the evaluation of left ventricular function in adult rodents : a position paper of the ESC Working Group on Myocardial Function

This work was supported by AIRC IG grant 2016 19032 to S.Z.; FEDER through Compete 2020 –Programa Operacional Competitividade E Internacionalização(POCI), the project DOCNET (norte-01-0145-feder-000003), supported by Norte Portugal regional operational programme (norte 2020), under the Portugal 2020 partnership agreement, through the European Regional Development Fund (ERDF), the project NETDIAMOND (POCI-01-0145-FEDER-016385), supported by European Structural And Investment Funds, Lisbon’s regional operational program 2020 to I.P.F.; grants from FSR-FNRS, FRC (Cliniques Universitaires Saint-Luc) and from Action de Recherche Concertée (UCLouvain) to C.B., E.P.D. and L.B; the ERA-Net-CVD project MacroERA,01KL1706, FP7-Homage N° 305507, and IMI2-CARDIATEAM (N° 821508)to S.H.,the DZHK (German Centre for Cardiovascular Research) and the German Ministry of Research and Education (BMBF)to F.W., T.E. and L.C., the Netherlands Cardiovascular Research Initiative, an initiative with support of the Dutch Heart Foundation, CVON2016-Early HFPEF, 2015-10, CVON She-PREDICTS, grant 2017-21, CVON Arena-PRIME, 2017-18, Flemish Research FoundationFWO G091018N and FWO G0B5930N to S.H.; Federico II University/Ricerca di Ateneo grant to C.G..T.; the European Research Area Networks on Cardiovascular Diseases (ERA-CVD) [LYMIT-DIS 2016, MacroERA], Fonds Wetenschappelijk Onderzoek [1160718N] to I.C; the Deutsche Forschungsgemeinschaft (DFG TH903/20-1, KFO311), the Transregio-SFB INST 95/15641 and the EU Horizon 2020 project Cardioregenix (GA 825670)to T.TPeer reviewedPostprin

Age-dependent pattern of cerebellar susceptibility to bilirubin neurotoxicity in vivo in mice

Neonatal jaundice is caused by high levels of unconjugated bilirubin. It is usually a temporary condition caused by delayed induction of UGT1A1, which conjugates bilirubin in the liver. To reduce bilirubin levels, affected babies are exposed to phototherapy (PT), which converts toxic bilirubin into water-soluble photoisomers that are readily excreted out. However, in some cases uncontrolled hyperbilirubinemia leads to neurotoxicity. To study the mechanisms of bilirubin-induced neurological damage (BIND) in vivo, we generated a mouse model lacking the Ugt1a1 protein and, consequently, mutant mice developed jaundice as early as 36 hours after birth. The mutation was transferred into two genetic backgrounds (C57BL/6 and FVB/NJ). We exposed mutant mice to PT for different periods and analyzed the resulting phenotypes from the molecular, histological and behavioral points of view. Severity of BIND was associated with genetic background, with 50% survival of C57BL/6‑Ugt1−/− mutant mice at postnatal day 5 (P5), and of FVB/NJ-Ugt1−/− mice at P11. Life-long exposure to PT prevented cerebellar architecture alterations and rescued neuronal damage in FVB/NJ-Ugt1−/− but not in C57BL/6-Ugt1−/− mice. Survival of FVB/NJ-Ugt1−/− mice was directly related to the extent of PT treatment. PT treatment of FVB/NJ-Ugt1−/− mice from P0 to P8 did not prevent bilirubin-induced reduction in dendritic arborization and spine density of Purkinje cells. Moreover, PT treatment from P8 to P20 did not rescue BIND accumulated up to P8. However, PT treatment administered in the time-window P0–P15 was sufficient to obtain full rescue of cerebellar damage and motor impairment in FVB/NJ-Ugt1−/− mice. The possibility to modulate the severity of the phenotype by PT makes FVB/NJ-Ugt1−/− mice an excellent and versatile model to study bilirubin neurotoxicity, the role of modifier genes, alternative therapies and cerebellar development during high bilirubin conditions