Challenges in Brugada Syndrome Stratification: Investigating SCN5A Mutation Localization and Clinical Phenotypes

Brugada Syndrome (BrS) is a genetic heart condition linked to sudden cardiac death. Though the SCN5A gene is primarily associated with BrS, there is a lack of comprehensive studies exploring the connection between SCN5A mutation locations and the clinical presentations of the syndrome. This study aimed to address this gap and gain further understanding of the syndrome. The investigation classified 36 high-risk BrS patients based on SCN5A mutations within the transmembrane/structured (TD) and intra-domain loops (IDLs) lacking a 3D structure. We characterized the intrinsically disordered regions (IDRs) abundant in IDLs, using bioinformatics tools to predict IDRs and post-translational modifications (PTMs) in NaV1.5. Interestingly, it was found that current predictive tools often underestimate the impacts of mutations in IDLs and disordered regions. Moreover, patients with SCN5A mutations confined to IDL regions-previously deemed 'benign'-displayed clinical symptoms similar to those carrying 'damaging' variants. Our research illuminates the difficulty in stratifying patients based on SCN5A mutation locations, emphasizing the vital role of IDLs in the NaV1.5 channel's functioning and protein interactions. We advocate for caution when using predictive tools for mutation evaluation in these regions and call for the development of improved strategies in accurately assessing BrS risk.

Interplay of Modified Sialic Acid Inhibitors and the Human Parainfluenza Virus 1 Hemagglutinin-Neuraminidase Active Site

In the search for effective antivirals against Paramyxoviridae, the dynamics of human parainfluenza virus type 1 hemagglutinin-neuraminidase (hPIV1-HN) inhibition offers a promising perspective. This study focuses on the potential of C5- and C4-modified 2,3-unsaturated sialic acid (DANA) inhibitors and highlights their interaction with the hPIV1-HN enzyme. We show that a strategic substitution, replacing the C5 isopropyl group in BCX 2798 with a trifluoroacetyl function, increases inhibitory potency 3- to 4-fold. At the same time, we explore the special properties of the catalytic site of hPIV1-HN, which harbors only small substituents and favors a C4 sulfonylamido function over a carbonyl function, in contrast to the C4 pocket of Newcastle disease virus hemagglutinin-neuraminidase (NDV-HN). Based on these findings, we present a newly identified potent inhibitor that has the preferred C5 trifluoroacetamido and C4 trifluorosulfonylamide groups. The results of this study pave the way for a deeper understanding of the C4 and C5 binding pockets of hPIV1-HN and promote the development of new, more selective inhibitors.

Age-induced alterations of granulopoiesis generate atypical neutrophils that aggravate stroke pathology

Aging accounts for increased risk and dismal outcome of ischemic stroke. Here, we investigated the impact of age-related changes in the immune system on stroke. Upon experimental stroke, compared with young mice, aged mice had increased neutrophil clogging of the ischemic brain microcirculation, leading to worse no-reflow and outcomes. Aged mice showed an enhanced granulopoietic response to stroke that led to the accumulation of CD101+CD62Llo mature and CD177hiCD101loCD62Llo and CD177loCD101loCD62Lhi immature atypical neutrophils in the blood, endowed with increased oxidative stress, phagocytosis and procoagulant features. Production of CXCL3 by CD62Llo neutrophils of the aged had a key role in the development and pathogenicity of aging-associated neutrophils. Hematopoietic stem cell rejuvenation reverted aging-associated neutropoiesis and improved stroke outcome. In elderly patients with ischemic stroke, single-cell proteome profile of blood leukocytes identified CD62Llo neutrophil subsets associated with worse reperfusion and outcome. Our results unveil how stroke in aging leads to a dysregulated emergency granulopoiesis impacting neurological outcome.

Analysis of the intramolecular 1,7-lactone of N-acetylneuraminic acid using HPLC-MS: relationship between detection and stability

A subclass of the sialic acid family consists of intramolecular lactones that may function as key indicators of physiological and pathological states. However, the existence of these compounds in free form is highly improbable, since they are unlikely to exist in an aqueous solution due to their lability. Current analytical method used to detect them in biological fluids has not recognized their reactivity in solution and is prone to misidentification. However, recent advances in synthetic methods for 1,7-lactones have allowed the preparation of these sialic acid derivatives as authentic reference standards. We report here the development of a new HPLC-MS method for the simultaneous detection of the 1,7-lactone of N-acetylneuraminic acid, its γ-lactone derivative, and N-acetylneuraminic acid that overcomes the limitations of the previous analytical procedure for their identification.

Design, Synthesis, and Antiviral Evaluation of Sialic Acid Derivatives as Inhibitors of Newcastle Disease Virus Hemagglutinin-Neuraminidase: A Translational Study on Human Parainfluenza Viruses

Global infections with viruses belonging to the Paramyxoviridae, such as Newcastle disease virus (NDV) or human parainfluenza viruses (hPIVs), pose a serious threat to animal and human health. NDV-HN and hPIVs-HN (HN hemagglutinin-neuraminidase) share a high degree of similarity in catalytic site structures; therefore, the development of an efficient experimental NDV host model (chicken) may be informative for evaluating the efficacy of hPIVs-HN inhibitors. As part of the broad research in pursuit of this goal and as an extension of our published work on antiviral drug development, we report here the biological results obtained with some newly synthesized C4- and C5-substituted 2,3-unsaturated sialic acid derivatives against NDV. All developed compounds showed high neuraminidase inhibitory activity (IC₅₀ 0.03-13 μM). Four molecules (9, 10, 23, 24) confirmed their high in vitro inhibitory activity, which caused a significant reduction of NDV infection in Vero cells, accompanied by very low toxicity.

Sphingolipids and Atherosclerosis: The Dual Role of Ceramide and Sphingosine-1-Phosphate

Sphingolipids are bioactive molecules that play either pro- and anti-atherogenic roles in the formation and maturation of atherosclerotic plaques. Among SLs, ceramide and sphingosine-1-phosphate showed antithetic properties in regulating various molecular mechanisms and have emerged as novel potential targets for regulating the development of atherosclerosis. In particular, maintaining the balance of the so-called ceramide/S1P rheostat is important to prevent the occurrence of endothelial dysfunction, which is the trigger for the entire atherosclerotic process and is strongly associated with increased oxidative stress. In addition, these two sphingolipids, together with many other sphingolipid mediators, are directly involved in the progression of atherogenesis and the formation of atherosclerotic plaques by promoting the oxidation of low-density lipoproteins (LDL) and influencing the vascular smooth muscle cell phenotype. The modulation of ceramide and S1P levels may therefore allow the development of new antioxidant therapies that can prevent or at least impair the onset of atherogenesis, which would ultimately improve the quality of life of patients with coronary artery disease and significantly reduce their mortality.

V-015 ROBOTIC TARUP: TECHNICAL DETAILS AND INNOVATIVE METHOD OF FIXATION

Aim

With the recent evolution of minimally invasive hernia repairing techniques, robotic platform has exponentially gained consensus in the field of abdominal wall surgery, leading to the placement of retromuscolar synthetic meshes avoiding the need of extensive tissue dissection as the open approach.

Our aim was to describe the introduction of Robotic Transabdominal Retromuscular Umbilical Prosthetic Hernia Repair (TARUP) at a referral centre for advanced mini-invasive surgery, by reporting the preliminary experience and the technical aspects of the procedure.

Material & Methods

We present a case of a 3 cm umbilical defect associated to supraumbilical diastasis in a young man undergoing TARUP with the Da Vinci Xi system. The robotic boom was placed on the patient's right side, with three trocars on the anterior axillary line. The outline for the mesh was marked by centering the hernia defect with transcutaneous needles to delineate the extent of dissection corresponding to mesh area. Intra-abdominal pressure was of 8–12 mmHg. A retromuscolar plane was created starting from the incision of the ipsilateral posterior rectus sheat. The hernia content was reduced. The junction between the anterior and posterior rectus fascia was incised to cross-over the linea alba and continue the dissection controlaterally. A 15×15 cm polypropylene mesh was positioned in the retrorectus space and fixed with cyanoacrylic glue tack.

Results

Intervention lenght was of 100 minutes. No intra- or post-operative complications occurred.

At present, no early recurrences were observed.

Conclusions

Robotic TARUP represents a safe and reproducible alternative in selected cases where retromuscolar mesh is preferred.

V-016 PARAHIATAL HERNIA: A RARE CASE OF DIAPHRAGMATIC HERNIA ROBOTICALLY REPAIRED

Aim

Parahiatal hernia is a rare type of diaphragmatic hernia, consisting in a adjacent but separated defect, lateral to the oesophageal hiatus and crus. It's not so familiar for surgeons, preoperative diagnosis is unlikely to be confirmed, and it is mostly found incidentally during intervention, leading to a complex and difficult repair.

We present a case of parahiatal hernia robotically treated with the aim of emphasizing how robotic system can successfully help surgeons in performing even unexpected confusing and challenging anatomic dissections and procedures.

Material and Methods

A 65-year-old woman underwent robotic parahiatal hernia repair at our Institution. Four robotic trocars were positioned along the transverse umbilical line with the additional Air-seal port at the periumbilical left side for assistant's use.

Dissection and isolation of both parahiatal defect and crural musculature were performed; the defect was closed with not absorbable barbed suture, conventional iatoplasty was also performed and a biosynthetic mesh was placed and fixed as a reinforcement.

Results

The duration of the intervention was of 100 minutes. No. intr- or post-operative complications occurred. Blood loss were inferior than 100 millilitres. The patient started oral intake at the second post-operative day and after discharged.

At six months no recurrences were detected.

Conclusions

Parahiatal hernia are rare entities of which surgeons should be aware. Robotic treatment is safe and feasible and it represents a good tool for a successful management.

V-023 R-TAPP AS A TRAINING MODEL IN ROBOTIC SURGERY

Aim

The main aim of the project will be evaluating the effectiveness of an experimental structured didactic program in robotic surgery in filling the training gap caused by the pandemic. We intend to evaluate how establishing a training pathway could improve young surgeons’ robotic skills and implement their participation in robotic procedures during the COVID-19 pandemic. We will also evaluate the learning curve of robotic transabdominal preperitoneal inguinal hernia repair (TAPP) for young surgeons with limited experience as first operators at the dual console.

Matherials and Methods

We designed an experimental stepwise training program in robotic surgery that starts from a first step of theoretical and laboratory lessons, followed by a second phase of bedside assistance training, and finally the completion of low complexity procedures by the trainees proctored at the dual console by senior surgeons. Robotic TAPP was selected as training model. The performance of each trainee will be registered in an evaluation data sheet and Learning scores will be recorded by the tutor with the evaluation of 6 corner steps of the procedure.

Results

Preliminary results showed improved technical skills and increased team spirit and wellbeing.

Conclusions

TAPP is a good training model because involves technical steps useful for more complex procedures. The robotic dual console represent an extraordinary training tool and a structured training program positively impacts technical skills and could help filling the training gap caused by the pandemic.

Neonatal Hyperglycemia and Neurodevelopmental Outcomes in Preterm Infants: A Review

Glucose impairment is common in preterm infants but the impact of early neonatal hyperglycemia on long term neurodevelopment is still highly controversial. This review reports current evidence of the effect of hyperglycemia on neurodevelopmental outcome. It was conducted according to the PRISMA guidelines. We searched MEDLINE via PubMed; EMBASE via Ovid; the Cochrane Central Register of Controlled Trials; the Cochrane Library; ClinicalTrials.gov; and the World Health Organization's International Trials Registry and Platform. We included studies that investigated the association between hyperglycemia, defined as at least one episode of glycemia ≥8 mmol/L, and neurodevelopment outcome evaluated either through the Griffiths Mental Developmental Scales (GMDS) or the Bayley Scales of Infant Development (BSID) for the first 5 years of life, and the Wechsler Intelligence Scale for Children (WISC) and the Movement Assessment Battery for Children (MABC) for the following age category. We selected six studies, comprising 2226 infants in total and which included 1059 (48%) infants for whom neurodevelopment assessment was available. We found an association between hyperglycemia and neurological delay in the first two years of life, especially for motor functions; this result was confirmed in later childhood. The quality of evidence was poor; therefore, the negative influence of neonatal hyperglycemia on the neurological development of preterm infants must be investigated in further studies.

Abstract P1040: The Protective Effects Of Sialidase Neu3 Against Cardiac Ischemia And Reperfusion Injury

The salvage of myocardium after acute myocardial infarction (AMI) can only be achieved by timely reperfusion. This is life-saving, however it may also lead to additional damage in the form of ischemia and reperfusion injury (IRI). Protecting cardiac tissue from IRI remains one of the greatest unmet clinical needs in cardiology. Therefore, a better understanding of IRI pathophysiology is necessary. There has been increasing recognition that the activation of specific molecular mechanisms, including the Reperfusion Injury Salvage Kinase (RISK) pathway and HIF-1α contributes to cardioprotection against IRI. Along this line, we previously reported that sialidase Neu3, which removes sialic acid from glycosphingolipids, controls HIF-1α activation via a prolyl hydroxylase-independent pathway. In fact, we found that Neu3 was up-regulated under chronic hypoxia in cyanotic congenital cardiac patients and its overexpression increased muscle cells’ resistance to hypoxic stress by activating the RISK pathway. In light of these premises, the goal of this study was to determine Neu3's involvement in the cardiac response to IRI and establish whether its inducible activation could promote cardioprotection. An IRI model in mice, obtained by temporarily blocking the LAD coronary artery, showed that Neu3 is modulated during this process. Notably, Neu3 showed progressive downregulation during the ischemic phase followed by its reactivation during reperfusion. These results were similar to the Neu3 modulation we observed in human cardiac cells (AC16) exposed to an IRI model in vitro . The overexpression of Neu3 during ischemia had beneficial effects both in terms of cell proliferation and reduction of oxidative stress after reperfusion. We found that Neu3 promotes the activation of glycolytic enzymes during the ischemic phase as well as the maintenance of the mitochondrial membrane potential, suggesting that the Neu3-overexpressing human cardiomyocyte undergoes more aerobic metabolism even in oxygen-deficient environments. In conclusion, these results support a role for Neu3 in cardioprotection against IRI, suggesting that it may be a useful therapeutic target for improving the recovery of patients who have undergone acute myocardial infarction.

Abstract P1099: Evidence Of Sialylation Pathway Alterations In Peripheral Blood Of Brugada Syndrome Patients

Brugada syndrome (BrS) is a cardiac arrhythmia associated with a higher risk of SCD. BrS is considered a genetic disorder, and the most commonly mutated gene is SCN5A, encoding the alpha subunit of the voltage-gated cardiac sodium channel (NaV1.5). Mutations of SCN5A usually lead to impairment of NaV1.5 functionality, which is considered the main mechanism of the disease. However, SCN5A mutations are responsible for only 30% of BrS cases. Therefore, it is conceivable that other mechanisms such as post-translational modifications (PTMs) affect NaV1.5 activity. Among others, sialylation may alter ion channel activity by carrying a sugar with a negative charge. Alterations in sialylation have been described in several cardiovascular diseases, as myocardial infarction, Chagas disease, and congenital disorders of glycosylation. For these reasons, the aim was to investigate changes in sialylation in BrS patients to obtain new information on the pathogenesis of BrS. Peripheral blood mononuclear cells (PBMCs) were collected from BrS patients and healthy controls. SNA lectin, a sialic acid-binding protein, was used to characterize the protein sialylation status of PBMCs by Western blot and flow cytometry. Gene expression of enzymes involved in the sialic acid pathway was also examined. The results showed a significant decrease in intracellular and extracellular protein sialylation levels in BrS PBMCs compared with controls. In addition, changes in gene expression of enzymes involved in the sialic acid pathway were detected. Moreover, these changes correlated with clinical parameters associated with phenotypic expression of the disease, such as arrhythmogenic BrS substrate area and potential duration. These findings support that BrS should be considered a systemic disease and are consistent with the presence of overlapping non-cardiac pathologies, as epilepsy, cancer, diabetes, skeletal muscle channelopathies, and laminopathies in BrS patients. Moreover, the discovery that molecular alterations can be found in the peripheral blood of BrS patients supports the existence of a biomarker of the disease. It is a challenge to develop an effective diagnostic test to screen broadly for BrS. In this direction, a multiomic study is ongoing in our center.

Human Sarcopenic Myoblasts Can Be Rescued by Pharmacological Reactivation of HIF-1α

Sarcopenia, an age-related decline in muscle mass and strength, is associated with metabolic disease and increased risk of cardiovascular morbidity and mortality. It is associated with decreased tissue vascularization and muscle atrophy. In this work, we investigated the role of the hypoxia inducible factor HIF-1α in sarcopenia. To this end, we obtained skeletal muscle biopsies from elderly sarcopenic patients and compared them with those from young individuals. We found a decrease in the expression of HIF-1α and its target genes in sarcopenia, as well as of PAX7, the major stem cell marker of satellite cells, whereas the atrophy marker MURF1 was increased. We also isolated satellite cells from muscle biopsies and cultured them in vitro. We found that a pharmacological activation of HIF-1α and its target genes caused a reduction in skeletal muscle atrophy and activation of PAX7 gene expression. In conclusion, in this work we found that HIF-1α plays a role in sarcopenia and is involved in satellite cell homeostasis. These results support further studies to test whether pharmacological reactivation of HIF-1α could prevent and counteract sarcopenia.

Neu3 Sialidase Activates the RISK Cardioprotective Signaling Pathway during Ischemia and Reperfusion Injury (IRI)

Coronary reperfusion strategies are life-saving approaches to restore blood flow to cardiac tissue after acute myocardial infarction (AMI). However, the sudden restoration of normal blood flow leads to ischemia and reperfusion injury (IRI), which results in cardiomyoblast death, irreversible tissue degeneration, and heart failure. The molecular mechanism of IRI is not fully understood, and there are no effective cardioprotective strategies to prevent it. In this study, we show that activation of sialidase-3, a glycohydrolytic enzyme that cleaves sialic acid residues from glycoconjugates, is cardioprotective by triggering RISK pro-survival signaling pathways. We found that overexpression of Neu3 significantly increased cardiomyoblast resistance to IRI through activation of HIF-1α and Akt/Erk signaling pathways. This raises the possibility of using Sialidase-3 activation as a cardioprotective reperfusion strategy after myocardial infarction.

Clinical Considerations for a Family with Dilated Cardiomyopathy, Sudden Cardiac Death, and a Novel TTN Frameshift Mutation

Dilated cardiomyopathy (DCM) is the leading indication for heart transplantation. TTN gene truncating mutations account for about 25% of familial DCM cases and for 18% of sporadic DCM cases. The clinical relevance of specific variants in TTN has been difficult to determine because of the sheer size of the protein for which TTN encodes, as well as existing extensive genetic variation. Clinicians should communicate novel clinically-relevant variants and genotype–phenotype associations, so that animal studies evaluating the molecular mechanisms are always conducted with a focus on clinical significance. In the present study, we report for the first time the novel truncating heterozygous variant NM_001256850.1:c.72777_72783del (p.Phe24259Leufs*51) in the TTN gene and its association with DCM in a family with sudden death. This variant occurs in the A-band region of the sarcomere, in a known mutational hotspot of the gene. Truncating titin variants that occur in this region are the most common cause of DCM and have been rarely reported in asymptomatic individuals, differently from other pathogenic TTN gene variants. Further studies are warranted to better understand this particular clinically-relevant variant.

The antithetic role of ceramide and sphingosine-1-phosphate in cardiac dysfunction

Cardiovascular diseases (CVDs) are the leading cause of death globally and the number of cardiovascular patients, which is estimated to be over 30 million in 2018, represent a challenging issue for the healthcare systems worldwide. Therefore, the identification of novel molecular targets to develop new treatments is an ongoing challenge for the scientific community. In this context, sphingolipids (SLs) have been progressively recognized as potent bioactive compounds that play crucial roles in the modulation of several key biological processes, such as proliferation, differentiation, and apoptosis. Furthermore, SLs involvement in cardiac physiology and pathophysiology attracted much attention, since these molecules could be crucial in the development of CVDs. Among SLs, ceramide and sphingosine-1-phosphate (S1P) represent the most studied bioactive lipid mediators, which are characterized by opposing activities in the regulation of the fate of cardiac cells. In particular, maintaining the balance of the so-called ceramide/S1P rheostat emerged as an important novel therapeutical target to counteract CVDs. Thus, this review aims at critically summarizing the current knowledge about the antithetic roles of ceramide and S1P in cardiomyocytes dysfunctions, highlighting how the modulation of their metabolism through specific molecules, such as myriocin and FTY720, could represent a novel and interesting therapeutic approach to improve the management of CVDs.

HIF-1α Directly Controls WNT7A Expression During Myogenesis

Herein we unveil that Hypoxia-inducible factor-1α (HIF-1α) directly regulates WNT7A expression during myogenesis. In fact, chromatin immunoprecipitation (ChiP) and site-directed mutagenesis experiments revealed two distinct hypoxia response elements (HREs) that are specific HIF-1α binding sites on the WNT7A promoter. Remarkably, a pharmacological activation of HIF-1α induced WNT7A expression and enhanced muscle differentiation. On the other hand, silencing of WNT7A using CRISPR/Cas9 genome editing blocked the effects of HIF-1α activation on myogenesis. Finally, treatment with prolyl hydroxylases (PHDs) inhibitors improved muscle regeneration in vitro and in vivo in a cardiotoxin (CTX)-induced muscle injury mouse model, paving the way for further studies to test its efficacy on acute and chronic muscular pathologies.

Reversine: A Synthetic Purine with a Dual Activity as a Cell Dedifferentiating Agent and a Selective Anticancer Drug

The development of new therapeutic applications for adult and embryonic stem cells has dominated regenerative medicine and tissue engineering for several decades. However, since 2006, induced Pluripotent Stem Cells (iPSCs) have taken center stage in the field, as they promised to overcome several limitations of the other stem cell types. Nonetheless, other promising approaches for adult cell reprogramming have been attempted over the years, even before the generation of iPSCs. In particular, two years before the discovery of iPSCs, the possibility of synthesizing libraries of large organic compounds, as well as the development of high-throughput screenings to quickly test their biological activity, enabled the identification of a 2,6-disubstituted purine, named reversine, which was shown to be able to reprogram adult cells to a progenitor-like state. Since its discovery, the effect of reversine has been confirmed on different cell types, and several studies on its mechanism of action have revealed its central role in inhibitory activity on several kinases implicated in cell cycle regulation and cytokinesis. These key features, together with its chemical nature, suggested a possible use of the molecule as an anti-cancer drug. Remarkably, reversine exhibited potent cytotoxic activity against several tumor cell lines in vitro and a significant effect in decreasing tumor progression and metastatization in vivo. Thus, 15 years since its discovery, this review aims at critically summarizing the current knowledge to clarify the dual role of reversine as a dedifferentiating agent and anti-cancer drug.

Abstract 255: Cardiac Ischemia and Reperfusion Injury: The Emerging Role of Sialidase Neu3

Reperfusion strategies, together with thrombolytic therapies, represent life-saving approaches to restore the blood flow in the cardiac tissue after acute myocardial infarction (AMI). However, they inevitably induce the so-called ischemia/reperfusion injury (IRI), resulting in increased cardiomyocytes damage and heart failure. In this context, many efforts have been made to clarify the molecular mechanisms involved in IRI, and the activation of pro-survival kinases, such as Akt and Erk, as well as of the hypoxia-inducible factor (HIF) has been recognized to be critical. Along this line, we discovered a novel mechanism of HIF-1α activation mediated by sialidase Neu3, which is PHDs independent, and that it increased muscle cells resistance to hypoxic stress, through the activation of Akt and Erk pathways. Moreover, an upregulation of Neu3 expression was observed under chronic hypoxia in cyanotic congenital cardiac patients.On these premises, this study aims at investigating the role of Neu3 in protecting cardiac cells against IRI. In particular, H9C2 rat cardiomyoblasts were exposed to an IRI model in vitro revealing a marked reduction in cell proliferation. This was accompanied by the modulation of Neu3 that was characterized by its progressive down-regulation during the ischemic phase, followed by its reactivation during reperfusion. These experiments resembled Neu3 modulation we observed in an IRI mouse model, obtained by the temporary occlusion of the LAD coronary vessel. Interestingly, overexpression of Neu3 significantly increased cardiomyoblasts resistance to IRI, both in terms of cell proliferation and resistance to apoptosis, as well as promoted HIF-1α and Akt/Erk activation. Remarkably, the treatment with Akt and Erk inhibitors completely reverted the beneficial effects mediated by Neu3 upregulation. Likewise, sialidase Neu3 inhibition reduced Akt/Erk activation, resulting in the complete loss of Neu3-mediated cardioprotection. In conclusion, our results demonstrate the role of sialidase Neu3 in counteracting the detrimental effects of IRI, calling for further studies to unveil its full potential as a therapeutic target to support current strategies to manage cardiac damage and to improve patients recover after AMI.

2β-3,4-Unsaturated sialic acid derivatives: Synthesis optimization, and biological evaluation as Newcastle disease virus hemagglutinin-neuraminidase inhibitors

The optimization of the synthetic protocol to obtain the 3,4-unsaturated sialic acid derivatives, through the fine-tuning of both the Ferrier glycosylation conditions and the subsequent hydrolysis work-up, is herein reported. The accomplishment of the desired β-anomers and some selected α-ones, in pure form, led us to evaluate their specific inhibitory activity towards NDV-HN and human sialidase NEU3. Importantly, the resulting data allowed the identification, for the first time, of three active 3,4-unsaturated sialic acid analogs, showing IC₅₀ values against NDV-HN in the micromolar range.

[Ethical approach to the issue of confinement of the elderly in the context of the COVID-19 pandemic: Prevention of frailty versus risk of vulnerability]

La pandémie à COVID-19 touche particulièrement les personnes les plus âgées et expose à un risque de mortalité les plus fragiles. Des mesures de confinement, de distanciation sociale et d’isolement ont été mises en place pour limiter la propagation virale. S’il existe un rationnel clair pour réduire la contagiosité de l’infection par ce biais, les conséquences néfastes de cet isolement social, en particulier pour cette population hétérogène, âgée et fragile sont difficiles à appréhender. En particulier, la rupture avec les structures habituelles de support et de soutien à domicile ou en institution, mais aussi le risque d’une diminution de « l’empowerment » de la personne âgée par rapport à ses propres décisions de santé et de vie sociale, imposent une vigilance particulière pour éviter un risque d’âgisme sociétal. Il peut ainsi exister, en regard de cette population particulière, des conflits de valeurs entre protection individuelle et collective, d’une part, et respect de l’autonomie et de l’indépendance, d’autre part. Cet article propose une réflexion éthique de la question du confinement des personnes âgées à risque de fragilités, s’appuyant sur des principes de l’éthique médicale, pour ouvrir les pistes de réflexion qui permettent une approche positive de la vulnérabilité, garante du respect de la dignité de la personne et de l’équité dans l’accès aux soins.

Mid-transverse colon cancer and extended versus transverse colectomy: Results of the Italian society of surgical oncology colorectal cancer network (SICO CCN) multicenter collaborative study

INTRODUCTION

Transverse colon cancer (TCC) is poorly studied, and TCC cases are often excluded from large prospective randomized trials because of their complexity and their potentially high complication rate. The best surgical approach for TCC has yet to be established. The aim of this large retrospective multicenter Italian series is to investigate the advantages and disadvantages of both hemicolectomy and transverse colectomy in order to identify the best surgical approach.

MATERIALS AND METHODS

This was a retrospective cohort study of patients with mid-transverse colon cancer treated with a segmental colon resection or an extended hemicolectomy (right or left) between 2006 and 2016 in 28 high-volume (more than 70 procedures/year) Italian referral centers for colorectal surgery.

RESULTS

The study included 1529 patients, 388 of whom underwent a segmental resection while 1141 underwent an extended resection. A higher number of complications has been reported in the segmental group than in the extended group (30.1% versus 23.6%; p 0.010). In 42 cases the main complication was the anastomotic leak (4.4% versus 2.2%; p 0.020). Recovery outcomes also showed statistical differences: time to first flatus (p 0.014), time to first mobilization (p 0.040), and overall hospital stay (p < 0.001) were significantly shorter in the extended group. Even if overall survival were similar between the groups (95.1% versus 97%; p 0.384), 3-year disease-free survival worsened after segmental resection (78.1% versus 86.2%; p 0.001).

CONCLUSIONS

According to our results, an extended right colon resection for TCC seems to be surgically safer and more oncologically valid.

Inhibition of Sphingolipid Synthesis as a Phenotype-Modifying Therapy in Cystic Fibrosis

BACKGROUND/AIMS

Cystic Fibrosis (CF) is an inherited disease associated with a variety of mutations affecting the CFTR gene. A deletion of phenylalanine 508 (F508) affects more than 70% of patients and results in unfolded proteins accumulation, originating a proteinopathy responsible for inflammation, impaired trafficking, altered metabolism, cholesterol and lipids accumulation, impaired autophagy at the cellular level. Lung inflammation has been extensively related to the accumulation of the lipotoxin ceramide. We recently proved that inhibition of ceramide synthesis by Myriocin reduces inflammation and ameliorates the defence response against pathogens infection, which is downregulated in CF. Here, we aim at demonstrating the mechanisms of Myriocin therapeutic effects in Cystic Fibrosis broncho-epithelial cells.

METHODS

The effect of Myriocin treatment, on F508-CFTR bronchial epithelial cell line IB3-1 cells, was studied by evaluating the expression of key proteins and genes involved in autophagy and lipid metabolism, by western blotting and real time PCR. Moreover, the amount of glycerol-phospholipids, triglycerides, and cholesterols, sphingomyelins and ceramides were measured in treated and untreated cells by LC-MS. Finally, Sptlc1 was transiently silenced and the effect on ceramide content, autophagy and transcriptional activities was evaluated as above mentioned.

RESULTS

We demonstrate that Myriocin tightly regulates metabolic function and cell resilience to stress. Myriocin moves a transcriptional program that activates TFEB, major lipid metabolism and autophagy regulator, and FOXOs, central lipid metabolism and anti-inflammatory/anti-oxidant regulators. The activity of these transcriptional factors is associated with the induction of PPARs nuclear receptors activity, whose targets are genes involved in lipid transport compartmentalization and oxidation. Transient silencing of SPTCL1 recapitulates the effects induced by Myriocin.

CONCLUSION

Cystic Fibrosis bronchial epithelia accumulate lipids, exacerbating inflammation. Myriocin administration: i) activates the transcriptions of genes involved in enhancing autophagy-mediated stress clearance; ii) reduces the content of several lipid species and, at the same time, iii) enhances mitochondrial lipid oxidation. Silencing the expression of Sptlc1 reproduces Myriocin induced autophagy and transcriptional activities, demonstrating that the inhibition of sphingolipid synthesis drives a transcriptional program aimed at addressing cell metabolism towards lipid oxidation and at exploiting autophagy mediated clearance of stress. We speculate that regulating sphingolipid de novo synthesis can relieve from chronic inflammation, improving energy supply and anti-oxidant responses, indicating an innovative therapeutic strategy for CF.

Single-shot morpho-functional and structural characterization of the left-ventricle in a mouse model of acute ischemia-reperfusion injury with an optimized 3D IntraGate cine FLASH sequence at 7T MR

Preclinical cardiac MR is challenging and time-consuming. A fast and comprehensive acquisition protocol and standardized image post-processing may improve preclinical research, reducing acquisition time, costs and variability of results. In the present study, we evaluated the feasibility of a contrast-enhanced 3D IntraGate steady-state cine sequence (ce-3D-IG-cine) with short acquisition time (11 min) for a single-shot combined characterization of left ventricle (LV) remodeling and infarct size (IS) in a mouse model of acute ischemia-reperfusion injury. Sixteen male C57BL/6N mice underwent 7T cardiac MR (Bruker, BioSpec 70/30) including optimized ce-3D-IG-cine (total scan time 11 min) at day 1, 5 and 28 after surgery. LV end-diastolic volume (EDV_MR) and ejection fraction (EF_MR) extracted from MR were compared to ones from short-axis (SA-EDV_echo, SA-EF_echo) and parasternal long-axis (LA-EDV_echo, LA-EF_echo) echocardiography. IS was manually and semiautomatically segmented from ce-3D-IG-cine using different standard deviation (SD +2, +3, +4, +5, +6 in respect to a reference tissue). Mice were sacrificed at day 28, immediately after imaging. IS at day 28 was compared to injury burden at histology. MR and echocardiographic morpho-functional parameters were compared, as IS from MR and histology. Bland-Altman plots were used to assess the agreement in ischemic burden segmentation. Volumetric and functional parameters measured on ce-3D-IG-cine correlated to the correspondent echocardiographic parameter (EDV_MR vs SA-EDV_echo: ρ = 0.813; EDV_MR vs LA-EDV_echo: ρ = 0.845; EF_MR vs SA-EF_echo ρ = 0.612; EF_MR vs LA-EF_echo ρ = 0.791; p < 0.001 in all cases). Manually segmented IS strongly correlated with the scar at histology (ρ = 0.904, p < 0.001). A threshold of +3SD showed the highest performance for semiautomatic assessment of IS compared to manual segmentation (ρ = 0.965, p < 0.001), with an overall reproducibility of 73%, and a peak reproducibility of 80% at day 1. The ce-3D-IG-cine sequence, manually or semiautomatically segmented using 3SD threshold, allows fast and comprehensive LV morpho-functional and structural characterization in myocardial ischemia-reperfusion injury model.

The acidic hydrolysis of N-acetylneuraminic 4,5-oxazoline allows a direct functionalization of the C5 position of Neu5Ac2en (DANA)

The Neu5Ac 4,5-oxazoline ring-opening allows the direct generation of a free C5-amino group key to synthesize antiviral drugs.

Sphingolipid Synthesis Inhibition by Myriocin Administration Enhances Lipid Consumption and Ameliorates Lipid Response to Myocardial Ischemia Reperfusion Injury

Myocardial infarct requires prompt thrombolytic therapy or primary percutaneous coronary intervention to limit the extent of necrosis, but reperfusion creates additional damage. Along with reperfusion, a maladaptive remodeling phase might occur and it is often associated with inflammation, oxidative stress, as well as a reduced ability to recover metabolism homeostasis. Infarcted individuals can exhibit reduced lipid turnover and their accumulation in cardiomyocytes, which is linked to a deregulation of peroxisome proliferator activated receptors (PPARs), controlling fatty acids metabolism, energy production, and the anti-inflammatory response. We previously demonstrated that Myriocin can be effectively used as post-conditioning therapeutic to limit ischemia/reperfusion-induced inflammation, oxidative stress, and infarct size, in a murine model. In this follow-up study, we demonstrate that Myriocin has a critical regulatory role in cardiac remodeling and energy production, by up-regulating the transcriptional factor EB, PPARs nuclear receptors and genes involved in fatty acids metabolism, such as VLDL receptor, Fatp1, CD36, Fabp3, Cpts, and mitochondrial FA dehydrogenases. The overall effects are represented by an increased β–oxidation, together with an improved electron transport chain and energy production. The potent immunomodulatory and metabolism regulatory effects of Myriocin elicit the molecule as a promising pharmacological tool for post-conditioning therapy of myocardial ischemia/reperfusion injury.

Abstract 880: The Role of Sialidase Neu3 in the Cardiac Response to Ischemia and Reperfusion Injury

Reperfusion strategies are life-saving approaches to restore the blood flow in the cardiac tissue after acute myocardial infarction (AMI). However, they come with the drawback that they inevitably induce ischemia/reperfusion injury (IRI), resulting in increased cardiomyocytes damage and heart failure. In this context, the physiological activation of several pro-survival kinases, such as Akt and Erk, as well as of the hypoxia inducible factor (HIF) has been recognized to be critical during IRI. Along with this line, we recently discovered a novel, PHDs independent, mechanism of HIF-1; activation mediated by sialidase Neu3. Interestingly, Neu3 is upregulated under chronic hypoxia in cyanotic congenital cardiac patients. Moreover, induced activation of Neu3 increased myoblast resistance to hypoxic stress. Thus, in this study, we further investigated the possible role of Neu3 in protecting cardiac myoblasts during IRI. In particular, we set-up an in-vitro model of IRI on H9C2 rat cardiomyoblasts. Results showed a modulation of Neu3 during IRI, with a progressive down-regulation during the ischemic phase, followed by a reactivation during the reperfusion phase. Remarkably, overexpression of Neu3 significantly increased cardiomyoblasts resistance to IRI, both in terms of cell proliferation and resistance to apoptosis. Treatment with Akt and Erk inhibitors, as well as with a Neu3 specific inhibitor completely reverted the beneficial effects mediated by Neu3 upregulation. In conclusion, our results show that Neu3 activation has a cardioprotective effect during IRI, calling for further studies to unveil its full potential as a therapeutic target to treat cardiac ischemia and reperfusion injury and to improve patients recover after AMI.

Genotype/Phenotype Relationship in a Consanguineal Family With Brugada Syndrome Harboring the R1632C Missense Variant in the SCN5A Gene

Brugada syndrome (BrS) is a known cause of sudden cardiac death. The genetic basis of BrS is not well understood, and no one single gene is linked to even a majority of BrS cases. However, mutations in the gene SCN5A are the most common, although the high amount of phenotypic variability prevents a clear correlation between genotype and phenotype. Research techniques are limited, as most BrS cases still remain without a genetic diagnosis, thus impairing the implementation of experimental models representative of a general pathogenetic mechanism. In the present study, we report the largest family to-date with the segregation of the heterozygous variant NM_198056:c.4894C>T (p.Arg1632Cys) in the SCN5A gene. The genotype-phenotype relationship observed suggests a likely pathogenic effect of this variant. Functional studies to better understand the molecular effects of this variant are warranted.

Lactonization Method To Assign the Anomeric Configuration of the 3,4-Unsaturated Congeners of N-Acetylneuraminic Acid

Assigning the correct configuration at C2 in sialosides is a standing problem because of the absence of an anomeric hydrogen. All different empirical rules that have been proposed over the years lack general applicability. In particular, the correct configuration of several 3,4-unsaturated derivatives of N-acetylneuraminic acid (Neu5Ac), which have been recently shown to be novel sialidase/neuraminidase inhibitors, could only be tentatively assigned by similarity with the reported 3,4-unsaturated 2O-methyl sialosides. In this work, we overcome this problem as we devised a rapid synthetic method to unequivocally resolve the anomeric configuration of the 3,4-unsaturated Neu5Ac derivatives through the synthesis of the corresponding unreported unsaturated 1,7-lactones. Moreover, we discovered a diagnostic ¹³C nuclear magnetic resonance signal that allows the formulation of a new empirical rule for the direct assignment of the C2 stereochemistry of these molecules, even when only one of the two C2 epimers is available.

Calcium in Brugada Syndrome: Questions for Future Research

The Brugada syndrome (BrS) is characterized by coved-type ST-segment elevation in the right precordial leads on the electrocardiogram (ECG) and increased risk of sudden cardiac death (SCD). While it is an inheritable disease, determining the true prevalence is a challenge, since patients may report no known family history of the syndrome, present with a normal spontaneous ECG pattern at the time of examination, and test negative for all known BrS-causative genes. In fact, SCD is often the first indication that a person is affected by the syndrome. Men are more likely to be symptomatic than women. Abnormal, low-voltage, fractionated electrograms have been found in the epicardium of the right ventricular outflow tract (RVOT). Ablation of this area abolishes the abnormal electrograms and helps to prevent arrhythmic recurrences. BrS patients are more likely to experience ventricular tachycardia/fibrillation (VT/VF) during fever or during an increase in vagal tone. Isoproterenol helps to reverse the ECG BrS phenotype. In this review, we discuss roles of calcium in various conditions that are relevant to BrS, such as changes in temperature, heart rate, and vagal tone, and the effects of gender and isoproterenol on calcium handling. Studies are warranted to further investigate these mechanisms in models of BrS.

A finite element analysis of diaphragmatic hernia repair on an animal model

The diaphragm is a mammalian skeletal muscle that plays a fundamental role in the process of respiration. Alteration of its mechanical properties due to a diaphragmatic hernia contributes towards compromising its respiratory functions, leading to the need for surgical intervention to restore the physiological conditions by means of implants. This study aims to assess via numerical modeling biomechanical differences between a diaphragm in healthy conditions and a herniated diaphragm surgically repaired with a polymeric implant, in a mouse model. Finite Element models of healthy and repaired diaphragms are developed from diagnostic images and anatomical samples. The mechanical response of the diaphragmatic tendon is described by assuming an isotropic hyperelastic model. A similar constitutive model is used to define the mechanical behavior of the polymeric implant, while the muscular tissue is modeled by means of a three-element Hill's model, specifically adapted to mouse muscle fibers. The Finite Element Analysis is addressed to simulate diaphragmatic contraction in the eupnea condition, allowing the evaluation of diaphragm deformation in healthy and herniated-repaired conditions. The polymeric implant reduces diaphragm excursion compared to healthy conditions. This explains the possible alteration in the mechanical functionality of the repaired diaphragm. Looking to the surgical treatment of diaphragmatic hernia in human neonatal subjects, this study suggests the implementation of alternative approaches based on the use of biological implants.

Descending genicular artery injury following transient lateral patellar dislocation

Transient lateral patellar dislocation (TLPD) is a common lesion in young adults. Vascular injury as a complication of TLPD has not been previously described. We report a case of descending genicular artery (DGA) injury after TLPD. Immediate angiography demonstrated rupture of DGA. Embolization was performed with sudden interruption of bleeding. DGA injury should be considered as a complication after TLPD and prompt diagnosis and intervention are required. We propose selective embolization as a safe and effective procedure to stop bleeding.

Synthesis and chemical characterization of several perfluorinated sialic acid glycals and evaluation of their in vitro antiviral activity against Newcastle disease virus

Newcastle Disease Virus (NDV), belonging to the Paramyxoviridae family, causes a serious infectious disease in birds, resulting in severe losses in the poultry industry every year. Haemagglutinin neuraminidase glycoprotein (HN) has been recognized as a key protein in the viral infection mechanism, and its inhibition represents an attractive target for the development of new drugs based on sialic acid glycals, with the 2-deoxy-2,3-didehydro-d-N-acetylneuraminic acid (Neu5Ac2en) as their backbone. Herein we report the synthesis of several Neu5Ac2en glycals and of their perfluorinated C-5 modified derivatives, including their respective stereoisomers at C-4, together with evaluation of their in vitro antiviral activity. While all synthesized compounds were found to be active HN inhibitors in the micromolar range, we found that their potency was influenced by the chain-length of the C-5 perfluorinated acetamido functionality. Thus, the binding modes of the inhibitors were also investigated by performing a docking study. Moreover, the perfluorinated glycals were found to be more active than the corresponding normal C-5 acylic derivatives. Finally, cell-cell fusion assays on NDV infected cells revealed that the addition of a newly synthesized C-4α heptafluorobutyryl derivative almost completely inhibited NDV-induced syncytium formation.

A chemical approach to myocardial protection and regeneration

The possibility of generating induced pluripotent stem cells from mouse embryonic fibroblasts and human adult fibroblasts has introduced new perspectives for possible therapeutic strategies to repair damaged hearts. However, obtaining large numbers of adult stem cells is still an ongoing challenge, and the safety of genetic reprogramming with lenti- or retro-viruses has several drawbacks not easy to be addressed. Furthermore, the majority of adult stem cell-based clinical trials for heart regeneration have had generally poor and controversial results. Nonetheless, it is now clear that the injected cells activate the growth and differentiation of progenitor cells that are already present in the heart. This is achieved by the release of signalling factors and/or exosomes carrying them. Along this line, chemistry may play a major role in developing new strategies for activating resident stem cells to regenerate the heart. In particular, this review focuses on small molecule approaches for cell reprogramming, cell differentiation, and activation of cell protection.

NEU3 Sialidase Protein Interactors in the Plasma Membrane and in the Endosomes

NEU3 sialidase has been shown to be a key player in many physio- and pathological processes, including cell differentiation, cellular response to hypoxic stress, and carcinogenesis. The enzyme, peculiarly localized on the outer leaflet of the plasma membrane, has been shown to be able to remove sialic acid residues from the gangliosides present on adjacent cells, thus creating cell to cell interactions. Nonetheless, herein we report that the enzyme localization is dynamically regulated between the plasma membrane and the endosomes, where a substantial amount of NEU3 is stored with low enzymatic activity. However, under opportune stimuli, NEU3 is shifted from the endosomes to the plasma membrane, where it greatly increases the sialidase activity. Finally, we found that NEU3 possesses also the ability to interact with specific proteins, many of which are different in each cell compartment. They were identified by mass spectrometry, and some selected ones were also confirmed by cross-immunoprecipitation with the enzyme, supporting NEU3 involvement in the cell stress response, protein folding, and intracellular trafficking.

Association between postoperative thromboembolism prophylaxis and complications following urological surgery

Thromboembolism represents the most significant complication and cause of non-surgical mortality in major urological surgery. The aim of the present study was to assess the association between the type of pharmacological thromboembolism prophylaxis and the postoperative complication rate in a cohort of patients undergoing major urological surgery. All consecutive patients treated with major urological surgery between December 2011 and March 2013 were evaluated. For each patient, clinical and demographic data, as well as information on the post-surgical complications and the type of pharmacological thromboembolism prophylaxis, were collected. In total, 453 patients (mean age, 63.36±12.05 years) were recruited (43.5% for prostate surgery, 33.1% for renal surgery, 12.1% for bladder surgery and 11.3% for other surgery). Postoperative blood transfusions were required in 50 cases (11.0%). A total of 32 patients (7.1%) underwent re-intervention due to the occurrence of grade ≥3 complications, with a readmission rate of 2.0%. According to the Clavien-Dindo Classification, the complications were grade 1 in 36.0% of the cases, grade 2 in 19.4%, grade 3 in 6.0%, grade 4 in 2.0% and grade 5 (mortality) in 0.7%. Only 1 case of deep venous thrombosis not associated with pulmonary thromboembolism was observed. Univariate analyses showed a significant negative association (higher risk of complications) between the use of >4,000 IU enoxaparin as the thromboembolism prophylaxis and postoperative blood transfusion rate (P=0.045), re-intervention rate (P=0.001) and the occurrence of grade ≥3 complications (P<0.001). Multivariate analysis confirmed the significant association between the use of >4,000 IU enoxaparin and both re-intervention rate (P=0.013) and occurrence of grade ≥3 complications (P=0.002). High doses of enoxaparin (>4,000 IU) may lead to an increased risk of re-intervention and severe postoperative complications following major urological surgery. Randomised, controlled trials comparing the effect of different types of pharmacological thromboembolism prophylaxis on postoperative complications following major urological surgery are required.

Improvement of diaphragmatic performance through orthotopic application of decellularized extracellular matrix patch

Muscle tissue engineering can provide support to large congenital skeletal muscle defects using scaffolds able to allow cell migration, proliferation and differentiation. Acellular extracellular matrix (ECM) scaffold can generate a positive inflammatory response through the activation of anti-inflammatory T-cell populations and M2 polarized macrophages that together lead to a local pro-regenerative environment. This immunoregulatory effect is maintained when acellular matrices are transplanted in a xenogeneic setting, but it remains unclear whether it can be therapeutic in a model of muscle diseases. We demonstrated here for the first time that orthotopic transplantation of a decellularized diaphragmatic muscle from wild animals promoted tissue functional recovery in an established atrophic mouse model. In particular, ECM supported a local immunoresponse activating a pro-regenerative environment and stimulating host muscle progenitor cell activation and migration. These results indicate that acellular scaffolds may represent a suitable regenerative medicine option for improving performance of diseased muscles.

Synthesis and biological evaluation of several dephosphonated analogues of CMP-Neu5Ac as inhibitors of GM3-synthase

Previous studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new treatments for ischemic diseases. Herein, the synthesis of several dephosphonated CMP-Neu5Ac congeners and their anti-GM3-synthase activity is reported. Biological activity testes revealed that some inhibitors almost completely blocked the GM3-synthase activity in vitro and reduced the GM3 content in living embryonic kidney 293A cells, eventually activating the epidermal growth factor receptor (EGFR) signaling cascade.