Actividad citotóxica y antiproliferativa de un extracto rico en fucoidan de Lessonia trabeculata sobre células de adenocarcinoma mamario murino 4T1

Introducción. Los tumores neoplásicos se caracterizan por su invasividad y metástasis. Las células neoplásicas tienen heterogeneidad genética, por lo cual pueden desarrollar resistencia a los quimioterápicos. Por esta razón, las plantas continúan siendo una fuente importante de nuevos productos anticancerígenos. Objetivo. Evaluar la actividad citotóxica y antiproliferativa de un extracto rico en fucoidan de Lessonia trabeculata nativa (EFLt) sobre la línea celular de adenocarcinoma mamario murino, triple negativo 4T1. Métodos. La citotoxicidad y la IC50 se determinaron en monocapas de 4T1 empleando el reactivo MTT. Para demostrar la actividad antiproliferativa se aplicaron los métodos de cierre de herida y anticlonogénico utilizando las IC50 del EFLt y Dox (doxorubicina). El cierre de herida fue evaluado mediante barrido de tiempos discretos; el efecto anticlonogénico fue evaluado 7 días postratamiento mediante el conteo de colonias y se determinó la fracción de sobrevivencia. Adicionalmente, se evaluaron la citotoxicidad y actividad antiproliferativa combinando las IC50 de EFLt y Dox. El porcentaje de migración y conteo de colonias se realizó con el programa ImageJ. Resultados. La IC50 del EFLt (950 μg/mL) produjo 56% de citotoxicidad, 80,3% de inhibición de la migración celular, 68% de inhibición en la formación de colonias. La IC50 de Dox fue 0,5 μg/mL. Conclusiones. El EFLt ejerce citotoxicidad dependiente de la concentración y tiene efecto antiproliferativo sobre 4T1. Se requiere continuar los ensayos en modelos de mayor complejidad que permitan esclarecer el potencial antitumoral del EFLt.

Introduction. Neoplastic tumors are characterized by invasiveness and metastasis. Neoplastic cells are genetically heterogeneous and can develop resistance to chemotherapeutic agents. For this reason, plants continue to be an important source of new anticancer products. Objective. To determine the cytotoxic and antiproliferative activity of a fucoidan-rich extract of native Lessonia trabeculata (EFLt) on the tripe negative murine mammary adenocarcinoma cell line 4T1. Methods. Cytotoxicity and IC50 were determined in 4T1 monolayers using the MTT reagent. To demonstrate antiproliferative activity, "wound" closure and anticlonogenic methods were applied using the IC50 of EFLt and Doc (doxorubicin). "Wound" closure was evaluated by discrete times sweep to determine percentage inhibition of cell migration; the anticlonogenic effect was evaluated by colony counting 7 days after treatment and the survival fraction was determined. In addition, cytotoxicity and antiproliferative activity were evaluated by combining the IC50 of EFLt and Dox. Percent migration and colony counts were performed using ImageJ software. Results. The IC50 (950 μg/mL) of EFLt was 56% cytotoxicity, 80,3% inhibition of cell migration, 68% inhibition of colony formation.The ICof Dox was 0,5 μg/mL. Conclusions. EFLt exerts concentration-dependent cytotoxicity and antiproliferative effect on 4T1. Further studies in more complex models are needed to elucidate the anti-tumor potential of EFLt.

Distal airway microbiome is associated with immunoregulatory myeloid cell responses in lung transplant recipients.

BACKGROUND: Long-term survival of lung transplant recipients (LTRs) is limited by the occurrence of bronchiolitis obliterans syndrome (BOS). Recent evidence suggests a role for microbiome alterations in the occurrence of BOS, although the precise mechanisms are unclear. In this study we evaluated the relationship between the airway microbiome and distinct subsets of immunoregulatory myeloid-derived suppressor cells (MDSCs) in LTRs. METHODS: Bronchoalveolar lavage (BAL) and simultaneous oral wash and nasal swab samples were collected from adult LTRs. Microbial genomic DNA was isolated, 16S rRNA genes amplified using V4 primers, and polymerase chain reaction (PCR) products sequenced and analyzed. BAL MDSC subsets were enumerated using flow cytometry. RESULTS: The oral microbiome signature differs from that of the nasal, proximal and distal airway microbiomes, whereas the nasal microbiome is closer to the airway microbiome. Proximal and distal airway microbiome signatures of individual subjects are distinct. We identified phenotypic subsets of MDSCs in BAL, with a higher proportion of immunosuppressive MDSCs in the proximal airways, in contrast to a preponderance of pro-inflammatory MDSCs in distal airways. Relative abundance of distinct bacterial phyla in proximal and distal airways correlated with particular airway MDSCs. Expression of CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP), an endoplasmic (ER) stress sensor, was increased in immunosuppressive MDSCs when compared with pro-inflammatory MDSCs. CONCLUSIONS: The nasal microbiome closely resembles the microbiome of the proximal and distal airways in LTRs. The association of distinct microbial communities with airway MDSCs suggests a functional relationship between the local microbiome and MDSC phenotype, which may contribute to the pathogenesis of BOS.

Extracorporeal membrane oxygenation in adults: A practical guide for internists.

The use of extracorporeal membrane oxygenation (ECMO) in adults has rapidly increased as the technology has evolved, although there is little definitive evidence that it is beneficial in this group. ECMO is now being used in acute respiratory distress syndrome (and was used extensively for this indication during the influenza H1N1 pandemic), as a bridge to lung or heart transplant, and in postcardiac arrest patients. We review the current evidence and indications for ECMO, focusing on its principles and practical aspects in adult patients with respiratory or cardiac failure.

Early initiation of extracorporeal membrane oxygenation improves survival in adult trauma patients with severe adult respiratory distress syndrome.

BACKGROUND: The use of extracorporeal membrane oxygenation (ECMO) in the trauma population has been reported to have a mortality benefit in patients with severe refractory hypoxic respiratory failure. This study compares the early initiation of ECMO for the management of severe adult respiratory distress syndrome (ARDS) versus a historical control immediately preceding the use of ECMO for trauma patients. METHODS: A retrospective study was conducted at a single verified Level I trauma center. The study population was limited to trauma patients diagnosed with severe ARDS using the Berlin definition (PaO2/FIO2 ratio < 100). Patients managed with ECMO versus conventional ventilation (CONV) were compared. The primary outcome of interest was mortality; secondary outcomes included hospital length of stay, intensive care unit-free days, and ventilator-free days. RESULTS: Fifteen ECMO patients managed from March 2013 to November 2014 were identified, as were 14 CONV patients managed from March 2012 to February 2013 who met the Berlin definition of severe ARDS. Data related to age, Injury Severity Scores (ISSs), admission lactic acid levels, base deficit, the number of transfused red blood cell units within the first 24 hours, and presence of severe traumatic brain injury were collected and were not statistically different between the groups. Likewise, Murray Lung Injury (MLI), Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores determined at the onset of severe ARDS were not statistically different between the groups. Median hospital stay (CONV, 28.0 days [14.0-47.0]; ECMO, 43.5 days [30.0-93.0]; p = 0.15), intensive care unit-free days (CONV, 0.0 days [0.0-5.0]; ECMO, 5.0 days [0.0-7.0]; p = 0.26), and ventilator-free days (CONV, 0.0 days [0.0-10.0]; ECMO, 8.0 days [0.0-19.0]; p = 0.13) were not statistically different between the groups. Mortality in the ECMO group was significantly reduced compared with the CONV group (ECMO, 13.3%; CONV, 64%; p = 0.01). Timing from the onset of severe ARDS to ECMO intervention occurred at a mean 1.9 ± 1.4 days. CONCLUSION: Patients who were treated with ECMO for severe ARDS had an improved mortality compared with historical controls. ECMO should be considered at the early onset of severe ARDS to improve survival. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Flexible Bronchoscopy Is Safe and Effective in Adult Subjects Supported With Extracorporeal Membrane Oxygenation.

BACKGROUND: Previous studies have demonstrated the safety of flexible bronchoscopy (FB) in mechanically ventilated subjects. However, the safety of FB in adult subjects receiving extracorporeal membrane oxygenation (ECMO) has not been described previously. METHODS: A retrospective review was conducted of all adult subjects who underwent FB while receiving ECMO support at the University of Alabama at Birmingham Hospital from January 1, 2013, to December 31, 2014. Physiologic variables, pre- and post-FB ECMO, and ventilator settings were recorded. RESULTS: 79 adult subjects underwent FB receiving ECMO with a total of 223 bronchoscopies. The most common indications for bronchoscopy included diagnostic evaluation of infection in subjects with pneumonia (29%) and clearance of excessive secretions (22%). In 70% of subjects, moderate or greater amounts of secretions were noted. FB yielded positive culture data in 37 subjects (47%), which resulted in a change to the antibiotic regimen in 14 subjects (38%) with positive culture data. No significant differences in mean PaO2 /FIO2 , mean ECMO flow, mean sweep gas, ventilator settings, or hemodynamic parameters (heart rate, oxygen saturation, and mean blood pressure) were noted before and after FB. Complications were mild and transient: blood-tinged secretions after FB in 21% cases, which resolved spontaneously, intraprocedural hypoxemia in 2.2% of cases, and dysrhythmia in <1% of cases. There were no episodes of ECMO cannula dislodgement or inadvertent extubation. CONCLUSIONS: FB can be used safely in adult subjects supported with ECMO and is not associated with significant hemodynamics changes, bleeding, or mechanical complications during ECMO support.

Automated Rotational Percussion Bed and Bronchoscopy Improves Respiratory Mechanics and Oxygenation in ARDS Patients Supported with Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) has been used to provide "lung rest" through the use of low tidal volume (6 ml/kg) and ultralow tidal volume (<6 ml/kg) ventilation in acute respiratory distress syndrome (ARDS). Low and ultralow tidal volume ventilation can result in low dynamic respiratory compliance and potentially increased retention of airway secretions. We present our experience using automated rotational percussion beds (ARPBs) and bronchoscopy in four ARDS patients to manage increased pulmonary secretions. These beds performed automated side-to-side tilt maneuver and intermittent chest wall percussion. Their use resulted in substantial reduction in peak and plateau pressures in two patients on volume control ventilation, while the driving pressures (inspiratory pressure) to attain the desired tidal volumes in patients on pressure control ventilation also decreased. In addition, mean partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2) ratio (109 pre-ARPB vs. 157 post-ARPB), positive end-expiratory pressure (10 cm H2O vs. 8 cm H2O), and FiO2 (0.88 vs. 0.52) improved after initiation of ARPB. The improvements in the respiratory mechanics and oxygenation helped us to initiate early ECMO weaning. Based on our experience, the use of chest physiotherapy, frequent body repositioning, and bronchoscopy may be helpful in the management of pulmonary secretions in patients supported with ECMO.

Use of ECMO in the Management of Severe Acute Respiratory Distress Syndrome: A Survey of Academic Medical Centers in the United States.

Mortality of severe acute respiratory distress syndrome (ARDS) remains high. Once conventional mechanical ventilation fails, alternative modes of therapy are used; most of which have limited evidence to support their use. No definitive guidelines exist for the management of these patients with alternate modalities of treatment. We conducted a cross-sectional national survey of 302 adult critical care training programs in the United States to understand the current preferences of intensivists regarding the use of different therapies for severe ARDS, including the use of extracorporeal membrane oxygenation (ECMO). A total of 381 responses were received: 203 critical care faculty and 174 critical care trainees. Airway pressure release ventilation was the initial choice of treatment reported by most when conventional mechanical ventilation strategy failed followed by inhaled nitric oxide and prone positioning. Extracorporeal membrane oxygenation availability was reported by 80% of the respondents at their institutions. Most respondents (83%) would consider ECMO in patients who fail optimal mechanical ventilation strategies, and the majority (60%) believed that ECMO use can facilitate lung protective ventilation, but few favored its use as a first-line modality. The majority of respondents reported limited knowledge of ECMO and desired specific ECMO education during training.

Successful Treatment of Severe Carbon Monoxide Poisoning and Refractory Shock Using Extracorporeal Membrane Oxygenation.

Carbon monoxide (CO) is the most common cause of poisoning and poisoning-related death in the United States. It is a tasteless and odorless poisonous gas produced from incomplete combustion of hydrocarbons, such as those produced by cars and heating systems. CO rapidly binds to hemoglobin to form carboxyhemoglobin, leading to tissue hypoxia, multiple-organ failure, and cardiovascular collapse. CO also binds to myocardial myoglobin, preventing oxidative phosphorylation in cardiac mitochondria and resulting in cardiac ischemia or stunning and cardiogenic pulmonary edema. Treatment of CO poisoning is mainly supportive, and supplemental oxygen remains the cornerstone of therapy, whereas hyperbaric oxygen therapy is considered for patients with evidence of neurological and myocardial injury. Extracorporeal membrane oxygenation (ECMO) has been utilized effectively in patients with respiratory failure and hemodynamic instability, but its use has rarely been reported in patients with CO poisoning. We report the successful use of venoarterial ECMO in a patient with severe CO poisoning and multiple-organ failure.

Extracorporeal membrane oxygenation after liver transplantation in a patient with hepatopulmonary syndrome and an atrial septal defect.

INTRODUCTION: Hepatopulmonary syndrome (HPS) is a rare complication of liver cirrhosis that may result in refractory hypoxemia even after liver transplantation. ECMO has been rarely used after liver transplantation or in patients with HPS. METHODS: We present a patient with HPS who underwent liver transplantation and developed refractory hypoxemia requiring postoperative ECMO support at our institution. During our review of literature we found nine reports of ECMO use for cardiorespiratory failure after liver transplant in the past. RESULTS: Our patient had persistent intrapulmonary shunting and developed severe respiratory failure after liver transplant. Additionally, the patient was found to have an atrial septal defect (ASD) and required percutaneous closure while receiving ECMO support. Literature review suggests that survival among these patients who were supported with ECMO after liver transplant was 50% and catastrophic bleeding complications were described in only one report. CONCLUSIONS: With careful selection of post-liver transplant patients and judicious management of anticoagulation, ECMO can be safely instituted in this cohort.

Modern use of extracorporeal life support in pregnancy and postpartum.

Extracorporeal membrane oxygenation (ECMO) use during pregnancy and the postpartum period are thought to be associated with an increased risk for maternal or fetal bleeding complications. We present our recent institutional experience in managing pregnant and postpartum patients with ECMO. We also performed a literature review of modern use of ECMO in pregnant and postpartum patients utilizing Pubmed and Embase databases. ECMO was used for severe cardiopulmonary failure due to multiple conditions. Based on published reports, overall maternal and fetal survival on ECMO were 80% and 70%, respectively. Mild-to-moderate vaginal bleeding was reported in a few cases, with rare occurrences of catastrophic postpartum hemorrhage. There was no consensus on an optimal anticoagulation strategy in these patients, though most preferred to keep anticoagulation at lower therapeutic levels. We conclude that ECMO, in well-selected pregnant and postpartum patients, appears to be safe and associated with low risk of maternal and fetal complications.

Influence of sex on chronic obstructive pulmonary disease risk and treatment outcomes.

Chronic obstructive pulmonary disease (COPD), one of the most common chronic diseases and a leading cause of death, has historically been considered a disease of men. However, there has been a rapid increase in the prevalence, morbidity, and mortality of COPD in women over the last two decades. This has largely been attributed to historical increases in tobacco consumption among women. But the influence of sex on COPD is complex and involves several other factors, including differential susceptibility to the effects of tobacco, anatomic, hormonal, and behavioral differences, and differential response to therapy. Interestingly, nonsmokers with COPD are more likely to be women. In addition, women with COPD are more likely to have a chronic bronchitis phenotype, suffer from less cardiovascular comorbidity, have more concomitant depression and osteoporosis, and have a better outcome with acute exacerbations. Women historically have had lower mortality with COPD, but this is changing as well. There are also differences in how men and women respond to different therapies. Despite the changing face of COPD, care providers continue to harbor a sex bias, leading to underdiagnosis and delayed diagnosis of COPD in women. In this review, we present the current knowledge on the influence of sex on COPD risk factors, epidemiology, diagnosis, comorbidities, treatment, and outcomes, and how this knowledge may be applied to improve clinical practices and advance research.

Characteristics of patients with pulmonary venoocclusive disease awaiting transplantation.

RATIONALE: Pulmonary venoocclusive disease (PVOD) is an uncommon cause of pulmonary arterial hypertension (PAH). However, unlike PAH, treatment options for PVOD are usually quite limited. The impact of the lung allocation score on access to transplantation for patients with PVOD and the clinical course of these patients have not been well-described. OBJECTIVES: To examine the association between the diagnosis of PVOD and lung transplantation for patients on the transplant waiting list. METHODS: Patients with a diagnosis of PVOD and PAH registered on the United Network for Organ Sharing wait list for transplantation from May 4, 2005 to May 3, 2013 were included. Lung transplantation was the primary outcome measure. Multivariable analyses were performed to determine the odds of dying or receiving a lung transplant after listing. Survival was compared using Kaplan-Meier and competing risks methods. RESULTS: Of 12,251 patients listed for lung transplantation, 49 with PVOD and 647 with PAH were identified. There were no significant differences in the lung allocation score between patients with PVOD and PAH at listing, transplant, or wait list removal for death/too sick for transplant. By 6 months, 22.6% of patients with PVOD had been removed from the wait list due to death, compared with 11.0% of patients with PAH (Chi-square P = 0.03). Patients with PVOD who died or were considered too sick for transplant were removed from the waiting list sooner after listing (22 vs. 105 d, P = 0.08). There was no difference in the proportion of patients with PVOD and PAH transplanted (50.0 vs. 47.6%, P = 0.60). CONCLUSIONS: In the lung allocation score era, patients with PVOD may be at higher risk for death while on the transplant waiting list. After wait list registration, close monitoring for disease progression is advised.

Acute demyelinating polyneuropathy after lung transplantation: guillain-barré syndrome or tacrolimus toxicity?

Guillain-Barré syndrome (GBS) has been described after solid organ and bone marrow transplantation mostly due to viral infections and possibly calcineurin inhibitors. Incidence after bone marrow transplant is 0.3-0.7%, though incidence in other transplants is not well known. We present the first description of tacrolimus associated GBS in lung transplant recipients in the English language literature. The pathophysiology of tacrolimus-induced polyneuropathy is not known, but some have hypothesized that tacrolimus induces an inflammatory phenomenon by differential effects on T cell subsets. Diagnosis of association may be challenging and requires high index of suspicion. The optimal treatment of GBS-associated with tacrolimus after lung transplantation is unknown, although drug discontinuation may result in improvement in some patients, while some reports suggest that the use of IVIG and/or plasmapheresis may be helpful and safe in organ transplant recipients with severe symptoms.

Epidemiology and prevalence of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) represents one of the main causes of morbidity and mortality worldwide. According to the World Health Organization, approximately 3 million people in the world die as a consequence of COPD every year. Tobacco use remains the main factor associated with development of disease in the industrialized world, but other risk factors are important and preventable causes of COPD, particularly in the developing world. The purpose of this review is to summarize the literature on the subject and to provide an update of the most recent advances in the field.

How to interpret surveys in medical research: a practical approach.

Surveys are being used increasingly in health-care research to answer questions that may be difficult to answer using other methods. While surveys depend on data that may be influenced by self-report bias, they can be powerful tools as physicians seek to enhance the quality of care delivered or the health care systems they work in. The purpose of this article is to provide readers with a basic framework for understanding survey research, with a goal of creating well-informed consumers. The importance of validation, including pretesting surveys before launch, will be discussed. Highlights from published surveys are offered as supplementary material.

COPD and gender differences: an update.

Chronic obstructive lung disease (COPD) is one of the most prevalent health conditions, and a major cause of morbidity and mortality around the globe. Once thought of primarily as a disease of men, COPD is now known to be increasingly prevalent among women. Although increasing tobacco consumption among women during the past several decades might explain some of this increase, the relationship may be more complex, including factors such as differential susceptibility to tobacco, anatomic and hormonal differences, behavioral differences, and differences in response to available therapeutic modalities. Moreover, women with COPD may present differently, may have a different pattern of comorbidities, and may have a better survival after acute exacerbations. Care providers continue to have a gender bias that may affect both diagnosis and treatment. Future work should focus on factors that lead to gender differences in COPD as well as gender-specific treatment strategies.