An Intercellular Flow of Glutathione Regulated by Interleukin 6 Links Astrocytes and the Liver in the Pathophysiology of Amyotrophic Lateral Sclerosis

Oxidative stress has been proposed as a major mechanism of damage to motor neurons associated with the progression of amyotrophic lateral sclerosis (ALS). Astrocytes are the most numerous glial cells in the central nervous system and, under physiological conditions, protect neurons from oxidative damage. However, it is uncertain how their reactive phenotype may affect motor neurons during ALS progression. In two different ALS mouse models (SOD1G93A and FUS-R521C), we found that increased levels of proinflammatory interleukin 6 facilitate glutathione (GSH) release from the liver to blood circulation, which can reach the astrocytes and be channeled towards motor neurons as a mechanism of antioxidant protection. Nevertheless, although ALS progression is associated with an increase in GSH efflux from astrocytes, generation of reactive oxygen species also increases, suggesting that as the disease progresses, astrocyte-derived oxidative stress could be key to motor-neuron damage

Oxidative Stress, Neuroinflammation and Mitochondria in the Pathophysiology of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron (MN) disease. Its primary cause remains elusive, although a combination of different causal factors cannot be ruled out. There is no cure, and prognosis is poor. Most patients with ALS die due to disease-related complications, such as respiratory failure, within three years of diagnosis. While the underlying mechanisms are unclear, different cell types (microglia, astrocytes, macrophages and T cell subsets) appear to play key roles in the pathophysiology of the disease. Neuroinflammation and oxidative stress pave the way leading to neurodegeneration and MN death. ALS-associated mitochondrial dysfunction occurs at different levels, and these organelles are involved in the mechanism of MN death. Molecular and cellular interactions are presented here as a sequential cascade of events. Based on our present knowledge, the discussion leads to the idea that feasible therapeutic strategies should focus in interfering with the pathophysiology of the disease at different steps

Glucocorticoid receptor antagonism overcomes resistance to BRAF inhibition in BRAFV600E-mutated metastatic melanoma

Clinical applications of glucocorticoids (GC) in Oncology are dependent on their pro-apoptotic action to treat lymphoproliferative cancers, and to alleviate side effects induced by chemotherapy and/or radiotherapy. However, the mechanism(s) by which GC may also promote tumor progression remains unclear. GC receptor (GR) knockdown decreases the antioxidant protection of highly metastatic B16-F10 melanoma cells. We hypothesize that a GR antagonist (RU486, mifepristone) could increase the efficacy of BRAF-related therapy in BRAFV600E-mutated metastatic melanoma. In vivo formed spontaneous skin tumors were reinoculated into nude mice to expand the metastases of different human BRAFV600E melanoma cells. The GR content of melanoma cell lines was measured by [3H]-labeled ligand binding assay. Nuclear Nrf2 and its transcription activity was investigated by RT-PCR, western blotting, and by measuring Nrf2- and redox state-related enzyme activities and metabolites. GR knockdown was achieved using lentivirus, and GR overexpression by transfection with the NR3C1 plasmid. shRNA-induced selective Bcl-xL, Mcl-1, AKT1 or NF-κB/p65 depletion was used to test the efficacy of vemurafenib (VMF) and RU486 against BRAFV600E-mutated metastatic melanoma. During early progression of skin melanoma metastases, RU486 and VMF induced a drastic metastases regression. However, treatment at an advanced stage of growth demonstrated the development of resistance to RU486 and VMF. This resistance was mechanistically linked to overexpression of specific proteins of the Bcl-2 family (Bcl-xL and Mcl-1 in our experimental models). We found that melanoma resistance is decreased if AKT and NF-κB signaling pathways are blocked. Our results highlight mechanisms by which metastatic melanoma cells adapt to survive.Medicin

Development and validation of a sample entropy-based method to identify complex patient-ventilator interactions during mechanical ventilation

Patient-ventilator asynchronies can be detected by close monitoring of ventilator screens by clinicians or through automated algorithms. However, detecting complex patient-ventilator interactions (CP-VI), consisting of changes in the respiratory rate and/or clusters of asynchronies, is a challenge. Sample Entropy (SE) of airway flow (SE-Flow) and airway pressure (SE-Paw) waveforms obtained from 27 critically ill patients was used to develop and validate an automated algorithm for detecting CP-VI. The algorithm’s performance was compared versus the gold standard (the ventilator’s waveform recordings for CP-VI were scored visually by three experts; Fleiss’ kappa = 0.90 (0.87–0.93)). A repeated holdout cross-validation procedure using the Matthews correlation coefficient (MCC) as a measure of effectiveness was used for optimization of different combinations of SE settings (embedding dimension, m, and tolerance value, r), derived SE features (mean and maximum values), and the thresholds of change (Th) from patient’s own baseline SE value. The most accurate results were obtained using the maximum values of SE-Flow (m = 2, r = 0.2, Th = 25%) and SE-Paw (m = 4, r = 0.2, Th = 30%) which report MCCs of 0.85 (0.78–0.86) and 0.78 (0.78–0.85), and accuracies of 0.93 (0.89–0.93) and 0.89 (0.89–0.93), respectively. This approach promises an improvement in the accurate detection of CP-VI, and future study of their clinical implications.This work was funded by projects PI16/01606, integrated in the Plan Nacional de R+D+I and co-funded by the ISCIII- Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER). RTC-2017-6193-1 (AEI/FEDER UE). CIBER Enfermedades Respiratorias, and Fundació Parc Taulí

Glucocorticoid receptor antagonism overcomes resistance to BRAF inhibition in BRAFV600E-mutated metastatic melanoma

Clinical applications of glucocorticoids (GC) in Oncology are dependent on their pro-apoptotic action to treat lymphoproliferative cancers, and to alleviate side effects induced by chemotherapy and/or radiotherapy. However, the mechanism(s) by which GC may also promote tumor progression remains unclear. GC receptor (GR) knockdown decreases the antioxidant protection of highly metastatic B16-F10 melanoma cells. We hypothesize that a GR antagonist (RU486, mifepristone) could increase the efficacy of BRAF-related therapy in BRAFV600E-mutated metastatic melanoma. In vivo formed spontaneous skin tumors were reinoculated into nude mice to expand the metastases of different human BRAFV600E melanoma cells. The GR content of melanoma cell lines was measured by [3H]-labeled ligand binding assay. Nuclear Nrf2 and its transcription activity was investigated by RT-PCR, western blotting, and by measuring Nrf2- and redox state-related enzyme activities and metabolites. GR knockdown was achieved using lentivirus, and GR overexpression by transfection with the NR3C1 plasmid. shRNA-induced selective Bcl-xL, Mcl-1, AKT1 or NF-κB/p65 depletion was used to test the efficacy of vemurafenib (VMF) and RU486 against BRAFV600E-mutated metastatic melanoma. During early progression of skin melanoma metastases, RU486 and VMF induced a drastic metastases regression. However, treatment at an advanced stage of growth demonstrated the development of resistance to RU486 and VMF. This resistance was mechanistically linked to overexpression of specific proteins of the Bcl-2 family (Bcl-xL and Mcl-1 in our experimental models). We found that melanoma resistance is decreased if AKT and NF-κB signaling pathways are blocked. Our results highlight mechanisms by which metastatic melanoma cells adapt to survive

Cardiopulmonary coupling indices to assess weaning readiness from mechanical ventilation

The ideal moment to withdraw respiratory supply of patients under Mechanical Ventilation at Intensive Care Units (ICU), is not easy to be determined for clinicians. Although the Spontaneous Breathing Trial (SBT) provides a measure of the patients’ readiness, there is still around 15–20% of predictive failure rate. This work is a proof of concept focused on adding new value to the prediction of the weaning outcome. Heart Rate Variability (HRV) and Cardiopulmonary Coupling (CPC) methods are evaluated as new complementary estimates to assess weaning readiness. The CPC is related to how the mechanisms regulating respiration and cardiac pumping are working simultaneously, and it is defined from HRV in combination with respiratory information. Three different techniques are used to estimate the CPC, including Time-Frequency Coherence, Dynamic Mutual Information and Orthogonal Subspace Projections. The cohort study includes 22 patients in pressure support ventilation, ready to undergo the SBT, analysed in the 24 h previous to the SBT. Of these, 13 had a successful weaning and 9 failed the SBT or needed reintubation –being both considered as failed weaning. Results illustrate that traditional variables such as heart rate, respiratory frequency, and the parameters derived from HRV do not differ in patients with successful or failed weaning. Results revealed that HRV parameters can vary considerably depending on the time at which they are measured. This fact could be attributed to circadian rhythms, having a strong influence on HRV values. On the contrary, significant statistical differences are found in the proposed CPC parameters when comparing the values of the two groups, and throughout the whole recordings. In addition, differences are greater at night, probably because patients with failed weaning might be experiencing more respiratory episodes, e.g. apneas during the night, which is directly related to a reduced respiratory sinus arrhythmia. Therefore, results suggest that the traditional measures could be used in combination with the proposed CPC biomarkers to improve weaning readiness

Cardiopulmonary coupling indices to assess weaning readiness from mechanical ventilation

The ideal moment to withdraw respiratory supply of patients under Mechanical Ventilation at Intensive Care Units (ICU), is not easy to be determined for clinicians. Although the Spontaneous Breathing Trial (SBT) provides a measure of the patients' readiness, there is still around 15-20% of predictive failure rate. This work is a proof of concept focused on adding new value to the prediction of the weaning outcome. Heart Rate Variability (HRV) and Cardiopulmonary Coupling (CPC) methods are evaluated as new complementary estimates to assess weaning readiness. The CPC is related to how the mechanisms regulating respiration and cardiac pumping are working simultaneously, and it is defined from HRV in combination with respiratory information. Three different techniques are used to estimate the CPC, including Time-Frequency Coherence, Dynamic Mutual Information and Orthogonal Subspace Projections. The cohort study includes 22 patients in pressure support ventilation, ready to undergo the SBT, analysed in the 24 h previous to the SBT. Of these, 13 had a successful weaning and 9 failed the SBT or needed reintubation -being both considered as failed weaning. Results illustrate that traditional variables such as heart rate, respiratory frequency, and the parameters derived from HRV do not differ in patients with successful or failed weaning. Results revealed that HRV parameters can vary considerably depending on the time at which they are measured. This fact could be attributed to circadian rhythms, having a strong influence on HRV values. On the contrary, significant statistical differences are found in the proposed CPC parameters when comparing the values of the two groups, and throughout the whole recordings. In addition, differences are greater at night, probably because patients with failed weaning might be experiencing more respiratory episodes, e.g. apneas during the night, which is directly related to a reduced respiratory sinus arrhythmia. Therefore, results suggest that the traditional measures could be used in combination with the proposed CPC biomarkers to improve weaning readiness

Objective and subjective cognition in survivors of COVID-19 one year after ICU discharge : the role of demographic, clinical, and emotional factors

Altres ajuts: This research was also supported by CIBER -Consorcio Centro de Investigación Biomédica en Red- CB06/06/1097, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea - European Regional Development Fund.Intensive Care Unit (ICU) COVID-19 survivors may present long-term cognitive and emotional difficulties after hospital discharge. This study aims to characterize the neuropsychological dysfunction of COVID-19 survivors 12 months after ICU discharge, and to study whether the use of a measure of perceived cognitive deficit allows the detection of objective cognitive impairment. We also explore the relationship between demographic, clinical and emotional factors, and both objective and subjective cognitive deficits. Critically ill COVID-19 survivors from two medical ICUs underwent cognitive and emotional assessment one year after discharge. The perception of cognitive deficit and emotional state was screened through self-rated questionnaires (Perceived Deficits Questionnaire, Hospital Anxiety and Depression Scale and Davidson Trauma Scale), and a comprehensive neuropsychological evaluation was carried out. Demographic and clinical data from ICU admission were collected retrospectively. Out of eighty participants included in the final analysis, 31.3% were women, 61.3% received mechanical ventilation and the median age of patients was 60.73 years. Objective cognitive impairment was observed in 30% of COVID-19 survivors. The worst performance was detected in executive functions, processing speed and recognition memory. Almost one in three patients manifested cognitive complaints, and 22.5%, 26.3% and 27.5% reported anxiety, depression and post-traumatic stress disorder (PTSD) symptoms, respectively. No significant differences were found in the perception of cognitive deficit between patients with and without objective cognitive impairment. Gender and PTSD symptomatology were significantly associated with perceived cognitive deficit, and cognitive reserve with objective cognitive impairment. One-third of COVID-19 survivors suffered objective cognitive impairment with a frontal-subcortical dysfunction 12 months after ICU discharge. Emotional disturbances and perceived cognitive deficits were common. Female gender and PTSD symptoms emerged as predictive factors for perceiving worse cognitive performance. Cognitive reserve emerged as a protective factor for objective cognitive functioning. Trial registration : ClinicalTrials.gov Identifier: NCT04422444; June 9, 2021. The online version contains supplementary material available at 10.1186/s13054-023-04478-7

Characterization of postintensive care syndrome in a prospective cohort of survivors of COVID-19 critical illness : a 12-month follow-up study

Purpose: Studies integrating an exhaustive longitudinal long-term follow-up of postintensive care syndrome (PICS) in critically ill COVID-19 survivors are scarce. We aimed to 1) describe PICS-related sequelae over a 12-month period after intensive care unit (ICU) discharge, 2) identify relevant demographic and clinical factors related to PICS, and 3) explore how PICS-related sequelae may influence health-related quality of life (HRQoL) in critically ill COVID-19 survivors. Methods: We conducted a prospective cohort study in adult critically ill survivors of SARS-CoV-2 infection that did or did not need invasive mechanical ventilation (IMV) during the COVID-19 pandemic in Spain (March 2020 to January 2021). We performed a telemedicine follow-up of PICS-related sequelae (physical/functional, cognitive, and mental health) and HRQoL with five data collection points. We retrospectively collected demographic and clinical data. We used multivariable mixed-effects models for data analysis. Results: We included 142 study participants in the final analysis, with a median [interquartile range] age of 61 [53-68] yr; 35% were female and 59% needed IMV. Fatigue/dyspnea, pain, impaired muscle function, psychiatric symptomatology and reduced physical HRQoL were prominent sequelae early after ICU discharge. Over the 12-month follow-up, functionality and fatigue/dyspnea improved progressively, while pain remained stable. We observed slight fluctuations in anxiety symptoms and perception of cognitive deficit, whereas posttraumatic stress disorder (PTSD) and depressive symptoms improved, with a mild rebound at the end of the follow-up. Female sex, younger age, and the need for IMV were risk factors for PICS, while having higher cognitive reserve was a potential protective factor. Physical HRQoL scores showed a general improvement over time, whereas mental HRQoL remained stable. Shorter ICU stay, better functionality, and lower scores for fatigue/dyspnea and pain were associated with better physical HRQoL, while lower scores for anxiety, depression, and PTSD were associated with better mental HRQoL. Conclusions: Postintensive care syndrome was common in COVID-19 critical illness survivors and persisted in a significant proportion of patients one year after ICU discharge, impacting HRQoL. The presence of risk factors for PICS may identify patients who are more likely to develop the condition and who would benefit from more specific and closer follow-up after ICU admission. Study registration: ClinicalTrials.gov (NCT04422444); first submitted 9 June 2020