Mutant huntingtin interacts with the sterol regulatory element-binding proteins and impairs their nuclear import.

Brain cholesterol homeostasis is altered in Huntington's disease (HD), a neurodegenerative disorder caused by the expansion of a CAG nucleotide repeat in the HTT gene. Genes involved in the synthesis of cholesterol and fatty acids were shown to be downregulated shortly after the expression of mutant huntingtin (mHTT) in inducible HD cells. Nuclear levels of the transcription factors that regulate lipid biogenesis, the sterol regulatory element-binding proteins (SREBP1 and SREBP2), were found to be decreased in HD models compared to wild-type, but the underlying causes were not known. SREBPs are synthesized as inactive endoplasmic reticulum-localized precursors. Their mature forms (mSREBPs) are generated upon transport of the SREBP precursors to the Golgi and proteolytic cleavage, and are rapidly imported into the nucleus by binding to importin ß. We show that, although SREBP2 processing into mSREBP2 is not affected in YAC128 HD mice, mSREBP2 is mislocalized to the cytoplasm. Chimeric mSREBP2-and mSREBP1-EGFP proteins are also mislocalized to the cytoplasm in immortalized striatal cells expressing mHTT, in YAC128 neurons and in fibroblasts from HD patients. We further show that mHTT binds to the SREBP2/importin ß complex required for nuclear import and sequesters it in the cytoplasm. As a result, HD cells fail to upregulate cholesterogenic genes under sterol-depleted conditions. These findings provide mechanistic insight into the downregulation of genes involved in the synthesis of cholesterol and fatty acids in HD models, and have potential implications for other pathways modulated by SREBPs, including autophagy and excitotoxicity.

Tuning the Potency of Farnesol-Modified Polyethylenimine with Polyanionic Trans-Booster to Enhance DNA Delivery.

Low molecular weight polyethylenimine (PEI) based lipopolymers become an attractive strategy to construct nonviral therapeutic carriers with promising transfection efficiency and minimal toxicity. Herein, this paper presents the design and synthesis of novel farnesol (Far) conjugated PEI, namely PEI1.2k-SA-Far7. The polymers had quick DNA complexation, effective DNA unpacking (dissociation), and cellular uptake abilities when complexed with plasmid DNA. However, they were unable to provide robust transfection in culture, indicating inability of Far grafting to improve the transfection efficacy significantly. To overcome this limitation, the commercially available polyanionic Trans-Booster additive, which is capable of displaying electrostatic interaction with PEI1.2k-SA-Far7, has been used to enhance the uptake of pDNA polyplexes and transgene expression. pDNA condensation was successfully achieved in the presence of the Trans-Booster with more stable polyplexes, and in vitro transfection efficacy of the polyplexes was improved to be comparable to that obtained with an established reference reagent. The PEI1.2k-SA-Far7/pDNA/Trans-Booster ternary complex exhibited good compatibility with cells and minimal hemolysis activity. This work demonstrates the exemplary potency of using additives in polyplexes and the potential of resultant ternary complexes for effective pDNA delivery.

Preventing Complications During Mapping and Ablation of Left Ventricular Summit Arrhythmias.

The left ventricular summit is a site of origin for idiopathic ventricular arrhythmias. With advancements in mapping and ablation techniques, sites previously considered inaccessible can now be approached. Anatomical knowledge of the 3-dimensional landmarks of this space is important, as critical structures reside within its boundaries and are potentially liable to collateral injury during ablation. This article reviews reported complications from ablation of ventricular arrhythmias arising from the left ventricular summit and its vicinity and discusses the pros and cons of different ablation technique and the role of an individualized anatomical approach to reduce procedural related complications and improve outcomes.

Transfection Efficacy and Cellular Uptake of Lipid-Modified Polyethyleneimine Derivatives for Anionic Nanoparticles as Gene Delivery Vectors.

Cationic polyethylenimine (PEI)-based nonviral gene carriers have been desirable to overcome the limitations of viral vectors in gene therapy. A range of PEI derivatives were designed, synthesized, and evaluated for nonviral delivery applications of plasmid DNA (pDNA). Linolenic acid, lauric acid, and oleic acid were covalently conjugated with low-molecular-weight PEI (Mw ∼ 1200 Da) via two different linkers, gallic acid (GA) and p-hydroxybenzoic acid (PHPA), that allows a differential loading of lipids per modified amine (3 vs 1, respectively). 1H NMR spectrum confirmed the expected structure of the conjugates as well as the level of lipid substitution. SYBR Green binding assay performed to investigate the 50% binding concentration (BC50) of lipophilic polymers to pDNA revealed increased BC50 with an increased level of lipid substitution. The particle analysis determined that GA- and PHPA-modified lipopolymers gave pDNA complexes with ∼300 and ∼100 nm in size, respectively. At the polymer/pDNA ratio of 5.0, the ζ-potentials of the complexes were negative (-6.55 to -10.6 mV) unlike the complexes with the native PEI (+11.2 mV). The transfection experiments indicated that the prepared lipopolymers showed higher transfection in attachment-dependent cells than in suspension cells based on the expression of the reporter green fluorescent protein (GFP) gene. When loaded with Cy3-labeled pDNA, the lipopolymers exhibited effective cellular uptake in attachment-dependent cells while the cellular uptake was limited in suspension cells. These results demonstrate the potential of lipid-conjugated PEI via GA and PHPA linkers, which are promising for the modification of anchorage-dependent cells.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction.

BACKGROUND: Our main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given. METHODS: An expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review. RESULTS: Numerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices. CONCLUSIONS: In some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

In-Cell Labeling Coupled to Direct Analysis of Extracellular Vesicles in the Conditioned Medium to Study Extracellular Vesicles Secretion with Minimum Sample Processing and Particle Loss.

Extracellular vesicles (EVs) are involved in a multitude of physiological functions and play important roles in health and disease. The largest proportion of studies on EVs is based on the analysis and characterization of EVs secreted in the cell culture medium. These studies remain challenging due to the small size of the EV particles, a lack of universal EV markers, and sample loss or technical artifacts that are often associated with EV labeling for single particle tracking and/or separation techniques. To address these problems, we characterized and validated a method for in-cell EV labeling with fluorescent lipids coupled with direct analysis of lipid-labeled EVs in the conditioned medium by imaging flow cytometry (IFC). This approach significantly reduces sample processing and loss compared to established methods for EV separation and labeling in vitro, resulting in improved detection of quantitative changes in EV secretion and subpopulations compared to protocols that rely on EV separation by size-exclusion chromatography and ultracentrifugation. Our optimized protocol for in-cell EV labeling and analysis of the conditioned medium reduces EV sample processing and loss, and is well-suited for cell biology studies that focus on modulation of EV secretion by cells in culture.

Neonatal progeroid syndrome (Wiedemann-Rautenstrauch syndrome): report of three affected sibs.

The Wiedemann-Rautenstrauch syndrome (WRS) (OMIM 264090) is a rare progeroid entity. WRS patients are characterized by premature aging present at birth including pseudohydrocephalus, cranio-facial disproportion, reduced subcutaneous fat, thin skin, rigid and thick joints, and neonatal teeth in some cases. Here we describe three sibs with WRS from unaffected parents and without consanguinity. Our findings support autosomal recessive inheritance in WRS and support the possibility of homozygocity mapping as a good approach to find the causative gene.

Sudden onset dyspnea caused by Bochdalek diaphragmatic hernia in an adult: a case report.

BACKGROUND: Bochdalek diaphragmatic hernia is a developmental defect of the posterolateral portion of the diaphragm. This defect may allow abdominal contents to abnormally occupy the thoracic cavity, resulting in most cases in the compression of the developing lungs. Signs are typically shown during early childhood since the defect is usually present during development. In exceptional cases, however, Bochdalek diaphragmatic hernia can be observed in asymptomatic adult patients, or in those whose initial diagnosis may include common respiratory pathologies such as asthma. CASE PRESENTATION: Here we describe the case of a 31-year-old Mestizo female patient admitted to the emergency room owing to sudden onset of pain in the left hypochondrium and in epigastrium, as well as signs of respiratory distress. Soon after admission, the patient entered cardiorespiratory arrest, and advanced cardiac life support was provided for 45 minutes without success. The patient was declared dead 1 hour 40 minutes after admission. Clinical autopsy concluded that cause of death was respiratory failure as a complication of a previously undiagnosed Bochdalek diaphragmatic hernia. CONCLUSIONS: We report an exceptional case of Bochdalek diaphragmatic hernia as the cause of rapid-onset respiratory failure and death in an adult. Unfortunately, due to its unusual presentation, Bochdalek diaphragmatic hernia is rarely considered among the list of differential diagnoses when admitting an adult patient with respiratory symptoms. By reporting this case, we encourage the medical community and trainees to consider diaphragmatic defects when approaching a patient with sudden onset of abdominal pain with concomitant respiratory symptoms.

Regulation of ceramide-induced neuronal death: cell metabolism meets neurodegeneration.

The present review explores the role of ceramides in neuronal apoptosis, as well as the recent discovery of the signaling pathways involved in this process placing particular emphasis on the correlation between cellular metabolism and neuronal death. Endogenous levels of ceramides are increased following various pro-apoptotic stimuli which have been identified as potential causes of chronic and acute neurodegenerative diseases. Ceramides induce changes in multiple enzymes and cell signaling components. The early inhibition of the neuronal survival pathway regulated by phosphatidil-inositol-3-kinase/protein kinase B or AKT mediated by ceramide may be a relevant early event in the decision of neuronal survival/death. It may perturb several molecular and metabolic functions. In particular it might decrease glycolysis through rapid modulation of hexokinase activity. This would in turn generate limited amounts of mitochondrial substrates leading to mitochondrial dysfunction and neuronal apoptosis. Subtle and early metabolic alterations caused by inhibition of the PI3K/AKT pathway mediated by ceramide may potentially work with genes associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Together they may be determinant steps in downstream events leading to neuronal apoptosis. Therefore, reinforcement of the PI3K/AKT pathway could constitute an important neuroprotective strategy.

Slc7a5 regulates Kv1.2 channels and modifies functional outcomes of epilepsy-linked channel mutations.

Kv1.2 is a prominent voltage-gated potassium channel that influences action potential generation and propagation in the central nervous system. We explored multi-protein complexes containing Kv1.2 using mass spectrometry followed by screening for effects on Kv1.2. We report that Slc7a5, a neutral amino acid transporter, has a profound impact on Kv1.2. Co-expression with Slc7a5 reduces total Kv1.2 protein, and dramatically hyperpolarizes the voltage-dependence of activation by -47 mV. These effects are attenuated by expression of Slc3a2, a known binding partner of Slc7a5. The profound Slc7a5-mediated current suppression is partly explained by a combination of gating effects including accelerated inactivation and a hyperpolarizing shift of channel activation, causing channels to accumulate in a non-conducting state. Two recently reported Slc7a5 mutations linked to neurodevelopmental delay exhibit a localization defect and have attenuated effects on Kv1.2. In addition, epilepsy-linked gain-of-function Kv1.2 mutants exhibit enhanced sensitivity to Slc7a5.

Disease-modifying effects of ganglioside GM1 in Huntington's disease models.

Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by motor, cognitive and psychiatric problems. Previous studies indicated that levels of brain gangliosides are lower than normal in HD models and that administration of exogenous ganglioside GM1 corrects motor dysfunction in the YAC128 mouse model of HD In this study, we provide evidence that intraventricular administration of GM1 has profound disease-modifying effects across HD mouse models with different genetic background. GM1 administration results in decreased levels of mutant huntingtin, the protein that causes HD, and in a wide array of beneficial effects that include changes in levels of DARPP32, ferritin, Iba1 and GFAP, modulation of dopamine and serotonin metabolism, and restoration of normal levels of glutamate, GABA, L-Ser and D-Ser. Treatment with GM1 slows down neurodegeneration, white matter atrophy and body weight loss in R6/2 mice. Motor functions are significantly improved in R6/2 mice and restored to normal in Q140 mice, including gait abnormalities that are often resistant to treatments. Psychiatric-like and cognitive dysfunctions are also ameliorated by GM1 administration in Q140 and YAC128 mice. The widespread benefits of GM1 administration, at molecular, cellular and behavioural levels, indicate that this ganglioside has strong therapeutic and disease-modifying potential in HD.

Impacto de la pandemia COVID-19 en la práctica de la electrofisiología cardíaca en Latinoamérica: una encuesta de la Sociedad Latinoamericana del Ritmo Cardíaco / Impact of the COVID-19 pandemic on the practice of cardiac electrophysiology in Latin America: a survey of the Latin American Heart Rhythm Society / Impacto da pandemia COVID-19 na prática da eletrofisiologia cardíaca na América Latina: uma pesquisa da Sociedade Latino-Americana de Ritmo Cardíaco

Al comienzo de la pandemia COVID-19 se implementaron pautas clínicas restrictivas de la asistencia que incluyeron los Servicios de Electrofisiología (SEF). Objetivo: analizar la actividad asistencial y conocer la situación de los SEF en Latinoamérica a dos meses de iniciadas las restricciones. Método: estudio observacional descriptivo-analítico y transversal, utilizando una encuesta a médicos electrofisiólogos en marzo/2020. Se comparó la actividad clínica e invasiva que se realizaba antes y durante la pandemia. Resultados: se incluyeron 147 encuestas, de 74 ciudades y 18 países de Latinoamérica. Los actos clínicos semanales se redujeron de 75 (45/127) a 20 (10/40) (p<0,001), bajaron 71%. Los procedimientos invasivos mensuales se redujeron de 26 (13/39) a 4 (2/9) (p<0,001), bajaron 77%. El 49% encuestado trabajaban en ≥3 centros asistenciales y 89% compartía laboratorio con un servicio de hemodinamia. La ocupación de camas en los hospitales era baja 37%, intermedia 28% y alta 35%. El 30% refirió algún médico de su equipo fue puesto en cuarentena por infección/contacto. El 53% refirió no se hacía ninguna prueba de tamizaje a los pacientes previa a los procedimientos y 77% al personal. La mayoría percibía dificultades como importantes o muy importantes, pero 63% estaba considerando la reapertura al funcionamiento normal. Conclusiones: hubo una reducción importante de la actividad clínica e invasiva. La mayoría no tenía alta ocupación de camas. Los encuestados trabajaban en varios centros y en salas de hemodinamia. Aún no se habían implementado totalmente las medidas de prevención. Existía la percepción de que en poco tiempo se retomaría la normalidad

At the beginning of the COVID-19 pandemic, restrictive clinical guidelines were implemented, including Electrophysiology Services (EFS). Objectives: analyze the healthcare activity and to know the situation of the EFS in Latin America two months after the restrictions began. Method: descriptive-analytical and cross-sectional observational study, using a survey of electrophysiologists in March / 2020. The clinical and invasive activity carried out before and during the pandemic was compared. Results: 147 surveys were included, from 74 cities in 18 Latin American countries. Weekly clinical events were reduced from 75 (45/127) to 20 (10/40) (p <0.001), they fell 71%. Monthly invasive procedures were reduced from 26 (13/39) to 4 (2/9) (p <0.001), down 77%. Forty-nine percent surveyed worked in ≥3 healthcare centers and 89% shared a laboratory with a hemodynamic service. Hospital bed occupancy was low 37%, intermediate 28% and high 35%. Thirty percent referred a doctor from their team was quarantined for infection / contact. Fifty-three percent reported that no screening test was done on the patients prior to the procedures and 77% on the staff. Most perceived difficulties as important or very important, but 63% were considering reopening to normal functioning. Conclusion: There was a significant reduction in clinical and invasive activity. Most did not have high bed occupancy. Respondents worked in various centers and in hemodynamic rooms. Prevention measures had not yet been fully implemented yet. There was a perception that in a short time normality would return.

No início da pandemia de COVID-19 foram implementadas diretrizes clínicas, incluindo os Serviços de Eletrofisiologia (SEF). Objetivo: analisar a atividade assistencial e conhecer a situação do SEF na América Latina dois meses após o início das restrições. Método: estudo descritivo-analítico e observacional transversal, por meio de questionário com eletrofisiologistas em março / 2020. Foi comparada a atividade clínica e invasiva realizada antes e durante a pandemia. Resultados: foram incluídos 147 inquéritos, de 74 cidades e 18 países latino-americanos. O número de procedimentos semanais foi reduzido de 75 (45/127) para 20 (10/40) (p <0,001), com redução de 71%. Os procedimentos invasivos mensais foram reduzidos de 26 (13/39) para 4 (2/9) (p <0,001), com redução de 77%. Dos eletrofisiologistas que responderam ao questionário, 49% trabalhavam em 3 ou mais centros, e 89% compartilhavam o laboratório com serviço de hemodinâmica. A ocupação de leitos hospitalares foi baixa em 37%, intermediária em 28% e alta em 35%. Dos que responderam al questionário, 30% relataram que um médico de sua equipe foi colocado em quarentena por infecção ou contato. Foi relatado que, dentre os que responderam, 53% não realizava teste de triagem nos pacientes antes dos procedimentos, e em 77% na equipe. A maioria percebeu as dificuldades como importantes ou muito importantes, mas 63% consideravam a reabertura ao funcionamento. Conclusões: houve redução significativa da atividade clínica e invasiva. A maioria não tinha grande ocupação de leitos. Os entrevistados trabalhavam em vários centros e em salas de hemodinâmica. As medidas de prevenção ainda não haviam sido totalmente implementadas, porém havia a percepção de que em pouco tempo a normalidade voltaria

Masa en cuello secundaria a electrodo de estimulación cardiaca abandonado / Neck mass secondary to an abandoned pacing lead

Mujer de 70 años de edad, con historia de un electrodo de estimulación cardiaca abandonado, que genera: un trastorno de la deglución y una deformidad estética que la hacen consultar en múltiples oportunidades. A pesar de que se planteó la opción del retiro quirúrgico, se logró una extracción endovascular por la tracción de un electrodo. Describimos la utilidad del eco intracardiaco y el catéter ENSnare®, para la extracción de los electrodos en este tipo de casos.

70-year-old woman with a history of an abandoned pacing lead who developed a deglutition disorder and an aesthetic deformity that made her consult in multiple specialties. Even though surgical removal was considered, endovascular extraction was accomplished with the traction of the lead. We describe the usefulness of the intracardiac echocardiography and the ENSnare® catheter for this type of lead extractions.

Differential regulation of AKT, MAPK and GSK3ß during C2-ceramide-induced neuronal death.

Evidence has implicated apoptosis as a mechanism underlying cell demise in diverse neurodegenerative diseases including Parkinson's disease (PD). Endogenous toxins and other stress signals activate the sphingomyelin pathway increasing the levels of ceramide, an important regulator of cell death. In the present paper we have analysed the contribution of PI3K/AKT-GSK3ß and MAPK (ERK and JNK) pathways to cell death in a catecholaminergic cell line following exposure to C(2)-ceramide. We also explored the potential neuroprotective action of insulin-like growth factor-1 (IGF-1) and neurotrophin-3 (NT3). We demonstrated that C(2)-ceramide-induced cell death is associated to an early decrease in phosphorylation (inhibition) of PI3K/AKT and ERK, followed by phosphorylation (activation) of JNK and de-phosphorylation (activation) of glycogen synthase kinase-3 beta (GSK3ß). NT3 and IGF-1 increased survival at early time points, but only IGF-1 is capable to attenuate C(2)-ceramide-mediated neuronal death, and this neuroprotection is associated to strong and permanent activation of AKT and inhibition of GSK3ß. In conclusion, C(2)-ceramide initiates a series of events including an early inactivation of PI3K/AKT and ERK pathways followed by activation of JNK and activation of GSK3ß and neuronal death, changes that are counteracted by IGF-1.

Fractura subtrocantérica patológica asociada al uso crónico de bifosfonatos: reporte de caso / Chronic use of biphosphonates associated with a pathological subthrocanteric femur fracture: case report

Se reporta el caso de una mujer de 65 años que había iniciado la toma de bifosfonatos (alendronato) secundario a una histerectomía total y a un diagnóstico de osteopenia hace 10 años. La paciente refiere inicialmente dolor en el tercio proximal del muslo de manera intermitente y posteriormente presenta una fractura subtrocantérica patológica de fémur. Por medio de lo encontrado en la literatura actual, se logra llegar a un diagnóstico y se cree que el uso crónico de alendronato pudo ser la causa de dicha fractura. El objetivo de este reporte de caso es alertar sobre el riesgo de fracturas subtrocantéricas de fémur con mínimo esfuerzo, además de la alteración de la consolidación de la misma, por el uso crónico de bifosfonatos.

Osteosíntesis Estable en Fracturas Conminutas de la Cúpula Radial

The goal of treatment of fractures of the radial head is full recovery of function with preservation of the elbow flexion and extension as well as pronation and supination of the forearm. Considerable confusion, however, continues to exist on how best to treat this type of fractures and that incluides: Type of classification. Type of treatment: 1. Conservative: there is no agreement concerning the period of movilization, should it be 1 week, 10 days, 3 weeks? 2.Operative: Parcial or total excision? head substitution? Timing of surgery: inmediate, delay? Long-term functional results have not been satisfactory in a considerable number of patients using these convetional techniques. Residual pain, and post-traumatic arthritis are not infrequent. Modern operative treatment of major intra-articular fractures according to the AO/ASIF methods and techniques have dramatically improved the overall results and we feel that these principles are perfectly valid in small joints like the radial head. Excellent preliminary results in 5 selected cases are presented and discussed