In vitro cellular models provide valuable insights into the adaptive biochemical mechanisms triggered by cells to cope with the stress situation induced by hypoxia and reoxygenation cycles. The first biological data generated in studies based on this micrometric life-scale has the potential to provide us a global overview about the main biochemical phenomena presented in some reported preconditioning therapies in life-scale of higher dimensions. Thus, in this study, a cell incubator was designed and manufactured to produce a cellular model of heart hypoxia followed by reoxygenation (HfR) through consecutive repetitions of hypoxia-normoxia gas exchange. Samples of cellular extracts and culture media were obtained from non-proliferative cardiomyocytes (CMs) cultivated under challenging HfR (stressed CMs) and regular cultivation (unstressed CMs) in rounds of four days for each case. Metabolomic based on proton magnetic resonance spectroscopy (1H-MRS) was used as an analytical approach to identify and quantify the metabolomes of these samples, the endo- and exo-metabolome. Despite the stressed CMs presented over 90% higher cellular death rate compared to the unstressed CMs, the metabolic profiles indicates that the surviving cells up-regulate their amino acid metabolism either by active protein degradation or by the consumption of culture media components to increase coenzyme A-dependent metabolic pathways. This cell auto-regulation mechanism could be well characterized in the first two days when the difference smears off under once the metabolomes become similar. The metabolic adaptations of stressed CMs identified the relevance of the cyclic oxidation/reduction reactions of nicotinamide adenine dinucleotide phosphate molecules, NADP+/NADPH, and the increased tricarboxylic acid cycle activity in an environment overloaded with such a powerful antioxidant agent to survive an extreme HfR challenge. Thus, the combination of cellular models based on CMs, investigative methods, such as metabolomic and 1H-MRS, and the instrumental development of hypoxia incubator shown in this work were able to provide the first biochemical evidences behind therapies of gaseous exchanges paving the way to future assays.
The interaction between silver nanoparticles (AgNPs) and molecules producing coronas plays a key role in cytotoxicity mechanisms. Once adsorbed coronas determine the destiny of nanomaterials in vivo, their effective deployment in the biomedical field requires a comprehensive understanding of the dynamic interactions of biomolecules with nanoparticles. In this work, we characterized 40 nm AgNPs in three different nutritional cell media at different molar concentrations and incubation times to study the binding mechanism of molecules on surface nanoparticles. In addition, their cytotoxic effects have been studied in three cell lineages used as tissue regeneration models: FN1, HUV-EC-C, RAW 264.7. According to the data, when biomolecules from DMEM medium were in contact with AgNPs, agglomeration and precipitation occurred. However, FBS medium proteins indicated the formation of coronas over the nanoparticles. Nonetheless, little adsorption of molecules around the nanoparticles was observed when compared to DMEM supplemented with 10% FBS. These findings indicate that when nanoparticles and bioproteins from supplemented media interact, inorganic salts from DMEM contribute to produce large bio-coronas, the size of which varies with the concentration and time. The static quenching mechanism was shown to be responsible for the fluorescence quenching of the bioprotein aggregates on the AgNPs surface. The calculated bioprotein-nanoparticle surface binding constants were on the order of 105 M-1 at 37 °C, with hydrophobic interactions driven by enthalpy and entropy playing a role, as confirmed by thermodynamic analysis. Cytotoxicity data showed a systematic degrowth in the viable cell population as the number of nanoparticles increased and the diameter of coronas decreased. Cytotoxic intervals associated with half decrease of cell population were established for AgNPs molar concentration of 75 µM for 24 h and 50 µM for 48 h. In summary, through the cytotoxicity mechanism of bio-coronas we are able to manipulate cells' expansion rates to promote specific processes, such inflammatory mechanisms, at different time instants.
Random-walk models are frequently used to model distinct natural phenomena such as diffusion processes, stock-market fluctuations, and biological systems. Here, we present a random-walk model to describe the dynamics of glucose uptake by the sodium-glucose transporter of type 2, SGLT2. Our starting point is the canonical alternating-access model, which suggests the existence of six states for the transport cycle. We propose the inclusion of two new states to this canonical model. The first state is added to implement the recent discovery that the Na+ion can exit before the sugar is released into the proximal tubule epithelial cells. The resulting model is a seven-state mechanism with stochastic steps. Then we determined the transition probabilities between these seven states and used them to write a set of master equations to describe the time evolution of the system. We showed that our model converges to the expected equilibrium configuration and that the binding of Na+and glucose to SGLT2 in the inward-facing conformation must be necessarily unordered. After that, we added another state to implement inhibition in the model. Our results reproduce the experimental dependence of glucose uptake on the inhibitor concentration and they reveal that the inhibitors act by decreasing the number of available SGLT2s, which increases the chances of glucose escaping reabsorption.
Sodium-Glucose Transporter 2 Inhibitors , Glucose/metabolism , Glucose Transport Proteins, Facilitative , Sodium/metabolism , Sodium-Glucose Transport Proteins , Sodium-Glucose Transporter 2/metabolism , Sodium-Glucose Transporter 2 Inhibitors/pharmacology
Objetivo: Analisar o conhecimento de médicos e enfermeiros da Estratégia Saúde da Família sobre as orientações nutricionais para diabetes mellitus tipo 2 (DM2) e hipertensão arterial sistêmica (HAS). Métodos: Estudo transversal e descritivo realizado com 67 médicos e enfermeiros de 11 Unidades de Atenção Primária à Saúde da Regional II do município de Fortaleza, Ceará, entre dezembro de 2019 e janeiro de 2020. Foram incluídos profissionais contratados, concursados ou participantes de programas de educação em serviço, aplicando-se um questionário fechado do tipo Likert, elaborado pelos pesquisadores, contendo 29 questões relacionadas às recomendações nutricionais das sociedades de referência em DM2 e HAS, e do Guia Alimentar para a População Brasileira. A análise dos dados ocorreu de forma descritiva, utilizando frequências absolutas e relativas e teste qui-quadrado. Resultados: A concordância com as diretrizes nutricionais das sociedades de referência de DM2 e HAS pelos profissionais foi de 17,9% (n=12) para a proporção de carboidratos na dieta do paciente diabético; 22,4% (n=15) para o consumo de café e controle da pressão arterial; 34,3% (n=23) para o consumo de açúcar pelo diabético e 37,3% (n=25) para o consumo de leite e controle da pressão arterial. Em relação às orientações do guia alimentar, a totalidade (n=67) dos entrevistados concordou que os alimentos ultraprocessados devem ser evitados, e que deve haver regularidade e atenção no consumo das refeições. Conclusão: Os profissionais apresentaram conhecimento insuficiente a respeito das recomendações nutricionais estabelecidas pelas principais sociedades nacionais e internacionais de DM2 e HAS.
Objective: To analyze the knowledge of doctors and nurses from the Family Health Strategy on nutritional guidelines for type 2 diabetes mellitus (DM2) and systemic arterial hypertension (SAH). Methods: Cross-sectional and descriptive study was carried out with 67 physicians and nurses from 11 Primary Health Care Units in Regional II in the city of Fortaleza, Ceará, between December 2019 and January 2020. service, applying a closed Likert-type questionnaire, prepared by the researchers, containing 29 questions related to the nutritional recommendations of reference societies in DM2 and SAH, and the Food Guide for the Brazilian Population. Data analysis was descriptive, using absolute and relative frequencies and the chi-square test. Results: The agreement of the nutritional guidelines of the reference societies of DM2 and SAH by the professionals was 17.9% (n=12) for the proportion of carbohydrates in the diabetic patient's diet; 22.4% (n=15) for coffee consumption and blood pressure control; 34.3% (n=23) for the consumption of sugar by the diabetic and 37.3% (n=25) for the consumption of milk and blood pressure control. Regarding the guidelines of the Food Guide, all (n=67) of the interviewees agreed that ultra-processed foods should be avoided and that there should be regularity and attention in the consumption of meals. Conclusion: The professionals showed a lack of knowledge about the nutritional recommendations established by the main national and international societies of DM2 and SAH.
Objetivo: Analizar el conocimiento de médicos y enfermeros de la Estrategia Salud de la Familia sobre las orientaciones nutricionales de la Diabetes Mellitus del tipo 2 (DM2) y la Hipertensión Arterial Sistémica (HAS). Métodos: Estudio transversal y descriptivo realizado con 67 médicos y enfermeros de 11 Unidades de Atención Primaria de Salud de la Regional II del municipio de Fortaleza, Ceará, Brasil, entre diciembre de 2019 y enero de 2020. Se ha incluido los profesionales contratados, los concursantes o los participantes de programas de educación en servicio aplicándose un cuestionario cerrado del tipo Likert elaborado por los investigadores con 29 preguntas relacionadas con las recomendaciones nutricionales de las sociedades de referencia en DM2 y HAS, y del Guía Alimentario para la Población Brasileña. El análisis de los datos se dio de modo descriptivo utilizándose las frecuencias absolutas y relativas y la prueba de chi-cuadrado. Resultados: La concordancia con las directrices nutricionales de las sociedades de referencia de DM2 y HAS por los profesionales ha sido del 17,9% (n=12) para la proporción de carbohidratos de la dieta del paciente diabético; el 22,4% (n=15) para el consumo de café y el control de la presión arterial; el 34,3% (n=23) para el consumo de azúcar por el diabético y el 37,3% (n=25) para el consumo de la leche y el control de la presión arterial. Respecto las orientaciones de la guía alimentaria, la totalidad (n=67) de los entrevistados estuvo de acuerdo de que se debe evitar a los alimentos ultra procesados y tener regularidad y atención con el consumo de las comidas. Conclusión: Los profesionales presentaron conocimiento insuficiente respecto las recomendaciones nutricionales establecidas por las principales sociedades nacionales e internacionales de DM2 y HAS.
Primary Health Care , Diabetes Mellitus , Recommended Dietary Allowances , Hypertension
We present a statistical mechanical model to describe the dynamics of an arbitrary cotransport system. Our starting point was the alternating access mechanism, which suggests the existence of six states for the cotransport cycle. Then we determined the 14 transition probabilities between these states, including a leak pathway, and used them to write a set of Master Equations for describing the time evolution of the system. The agreement between the asymptotic behavior of this set of equations and the result obtained from thermodynamics is a confirmation that leakage is compatible with the static head equilibrium condition and that our model has captured the essential physics of cotransport. In addition, the model correctly reproduced the transport dynamics found in the literature.
Knockout of multifunction gene cysteine- and glycine-rich protein 3 (CSRP3) in cardiomyocytes (CMs) of mice leads to heart dilation, severely affecting its functions. In humans, CSRP3 mutations are associated with hypertrophic (HCM) and dilated cardiomyopathy (DCM). The absence of the CSRP3 expression produces unknown effects on in vitro neonatal CMs' metabolism. The metabolome changes in culture media conditioned by CSRP3 knockout (KO-CSRP3), and wild type (WT) neonatal cardiomyocytes were investigated under untreated or after metabolic challenging conditions produced by isoproterenol (ISO) stimulation, by in vitro high-resolution proton magnetic resonance spectroscopy (1H-MRS)-based metabolomics. Metabolic differences between neonatal KO-CSRP3 and WT rats' CMs were identified. After 72 h of culture, ISO administration was associated with increased CMs' energy requirements and increased levels of threonine, alanine, and 3-hydroxybutyrate in both neonatal KO-CSRP3 and WT CMs conditioned media. When compared with KO-CSRP3, culture media derived from WT cells presented higher lactate concentrations either under basal or ISO-stimulated conditions. The higher activity of ketogenic biochemical pathways met the elevated energy requirements of the contractile cells. Both cells are considered phenotypically indistinguishable in the neonatal period of animal lives, but the observed metabolic stress responses of KO-CSRP3 and WT CMs to ISO were different. KO-CSRP3 CMs produced less lactate than WT CMs in both basal and stimulated conditions. Mainly, ISO-stimulated conditions produced evidence for lactate overload within KO-CSRP3 CMs, while WT CMs succeeded to manage the metabolic stress. Thus, 1H-MRS-based metabolomics was suitable to identify early inefficient energetic metabolism in neonatal KO-CSRP3 CMs. These results may reflect an apparent lower lactate transport and consumption, in association with protein catabolism.
Culture Media/chemistry , LIM Domain Proteins/metabolism , Muscle Proteins/metabolism , Myocytes, Cardiac/metabolism , Proton Magnetic Resonance Spectroscopy , Animals , Animals, Newborn , Cell Shape , Discriminant Analysis , Isoproterenol/pharmacology , LIM Domain Proteins/deficiency , Least-Squares Analysis , Muscle Proteins/deficiency , Myocytes, Cardiac/cytology , Myocytes, Cardiac/drug effects , Rats , Statistics as Topic
We present a new Monte Carlo method to simulate ionic liquids in slab geometry at constant potential. The algorithm is built upon two previous methods while retaining the advantages of each of them. The method is tested against a Poisson-Boltzmann theory and the constant surface charge ensemble, achieving consistency among all of them. We then analyze the computational time of the developed algorithm, showing substantial speedup in relation to the method of Kiyohara and Asaka [J. Chem. Phys., 2007, 126, 214704]. As an application of our method, we investigate crowding and overscreening in confined room-temperature ionic liquids. We show that we can switch between two behaviors of the double layer by changing the Bjerrum length alone.
BACKGROUND: Protective mechanical ventilation is recommended for patients with acute respiratory distress syndrome (ARDS), but it usually requires controlled ventilation and sedation. Using neurally adjusted ventilatory assist (NAVA) or pressure support ventilation (PSV) could have additional benefits, including the use of lower sedative doses, improved patient-ventilator interaction and shortened duration of mechanical ventilation. We designed a pilot study to assess the feasibility of keeping tidal volume (VT) at protective levels with NAVA and PSV in patients with ARDS. METHODS: We conducted a prospective randomized crossover trial in five ICUs from a university hospital in Brazil and included patients with ARDS transitioning from controlled ventilation to partial ventilatory support. NAVA and PSV were applied in random order, for 15 min each, followed by 3 h in NAVA. Flow, peak airway pressure (Paw) and electrical activity of the diaphragm (EAdi) were captured from the ventilator, and a software (Matlab, Mathworks, USA), automatically detected inspiratory efforts and calculated respiratory rate (RR) and VT. Asynchrony events detection was based on waveform analysis. RESULTS: We randomized 20 patients, but the protocol was interrupted for five (25%) patients for whom we were unable to maintain VT below 6.5 mL/kg in PSV due to strong inspiratory efforts and for one patient for whom we could not detect EAdi signal. For the 14 patients who completed the protocol, VT was 5.8 ± 1.1 mL/kg for NAVA and 5.6 ± 1.0 mL/kg for PSV (p = 0.455) and there were no differences in RR (24 ± 7 for NAVA and 23 ± 7 for PSV, p = 0.661). Paw was greater in NAVA (21 ± 3 cmH2O) than in PSV (19 ± 3 cmH2O, p = 0.001). Most patients were under continuous sedation during the study. NAVA reduced triggering delay compared to PSV (p = 0.020) and the median asynchrony Index was 0.7% (0-2.7) in PSV and 0% (0-2.2) in NAVA (p = 0.6835). CONCLUSIONS: It was feasible to keep VT in protective levels with NAVA and PSV for 75% of the patients. NAVA resulted in similar VT, RR and Paw compared to PSV. Our findings suggest that partial ventilatory assistance with NAVA and PSV is feasible as a protective ventilation strategy in selected ARDS patients under continuous sedation. Trial registration ClinicalTrials.gov (NCT01519258). Registered 26 January 2012, https://clinicaltrials.gov/ct2/show/NCT01519258.
OBJECTIVE: Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a disease that features a mechanical dysfunction involving chronic inflammation and altered tissue remodeling. In this study, we aim to evaluate the fibroblast morphology and its cellular traction force in primary fibroblasts cell cultures obtained from both healthy individuals (n=7) and patients with CRSwNP (n=8). METHODS: Using a Traction-force Microscopy we analyzed parameters of Force/Tension in fibroblasts cultures in both experimental groups. RESULTS: The analysis of the Projected Area of Cell revealed that fibroblasts derived from nasal mucosa of healthy individuals have an area on average 39.24% larger than the fibroblasts obtained from the nasal polyp tissue. We also observed that the parameters directly related to the force of the cell, Max Cumulative Force and Net Contractile Moment, presented a high Force/Tension per unit of area in the fibroblasts derived from the healthy nasal mucosa (on average 41% and 52.54% higher than the fibroblasts of the nasal polyp respectively). CONCLUSION: Our results demonstrate a cellular mechanism that may be associated with the mechanical dysfunction found in the Nasal Polyp tissue. The weak traction force of nasal polyp-derived fibroblast may, in lower dimensions, impact on the remodeling of nasal mucosa in CRSwNP.
Biomechanical Phenomena , Fibroblasts/ultrastructure , Nasal Polyps/ultrastructure , Pseudopodia/ultrastructure , Case-Control Studies , Chronic Disease , Female , Fibroblasts/pathology , Fibroblasts/physiology , Humans , Male , Microscopy, Atomic Force , Microscopy, Phase-Contrast , Middle Aged , Nasal Polyps/pathology , Nasal Polyps/physiopathology , Primary Cell Culture , Pseudopodia/pathology , Rhinitis/pathology , Sinusitis/pathology
Mechanisms whereby fibrillin-1 mutations determine thoracic aorta aneurysms/dissections (TAAD) in Marfan Syndrome (MFS) are unclear. Most aortic aneurysms evolve from mechanosignaling deregulation, converging to impaired vascular smooth muscle cell (VSMC) force-generating capacity accompanied by synthetic phenotype switch. However, little is known on VSMC mechanoresponses in MFS pathophysiology. Here, we investigated traction force-generating capacity in aortic VSMC cultured from 3-month old mg∆lpn MFS mice, together with morpho-functional and proteomic data. Cultured MFS-VSMC depicted marked phenotype changes vs. wild-type (WT) VSMC, with overexpressed cell proliferation markers but either lower (calponin-1) or higher (SM alpha-actin and SM22) differentiation marker expression. In parallel, the increased cell area and its complex non-fusiform shape suggested possible transition towards a mesenchymal-like phenotype, confirmed through several markers (e.g. N-cadherin, Slug). MFS-VSMC proteomic profile diverged from that of WT-VSMC particularly regarding lower expression of actin cytoskeleton-regulatory proteins. Accordingly, MFS-VSMC displayed lower traction force-generating capacity and impaired contractile moment at physiological substrate stiffness, and markedly attenuated traction force responses to enhanced substrate rigidity. Such impaired mechanoresponses correlated with decreased number, altered morphology and delocalization of focal adhesions, as well as disorganized actin stress fiber network vs. WT-VSMC. In VSMC cultured from 6-month-old mice, phenotype changes were attenuated and both WT-VSMC and MFS-VSMC generated less traction force, presumably involving VSMC aging, but without evident senescence. In summary, MFS-VSMC display impaired force-generating capacity accompanying a mesenchymal-like phenotype switch connected to impaired cytoskeleton/focal adhesion organization. Thus, MFS-associated TAAD involves mechanoresponse impairment common to other TAAD types, but through distinct mechanisms.
Marfan Syndrome/pathology , Muscle, Smooth, Vascular/pathology , Myocytes, Smooth Muscle/pathology , Actins/metabolism , Animals , Aorta/metabolism , Aorta/pathology , Aortic Aneurysm/metabolism , Aortic Aneurysm/pathology , Biomarkers/metabolism , Cell Differentiation/physiology , Cell Proliferation/physiology , Cells, Cultured , Cytoskeleton/metabolism , Cytoskeleton/pathology , Disease Models, Animal , Female , Fibrillin-1/metabolism , Focal Adhesions/metabolism , Focal Adhesions/pathology , Male , Marfan Syndrome/metabolism , Mice , Mice, Inbred C57BL , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/metabolism , Phenotype , Proteomics/methods
We present Monte Carlo simulations for the transport cycle of Escherichia coli lactose permease (LacY), using as a starting point the model proposed by Kaback et al. [Nat. Rev. Mol. Cell Biol. 2, 610 (2001)NRMCBP1471-007210.1038/35085077], which is based on functional properties of mutants and x-ray structures. Kaback's model suggests the existence of six states for the whole cycle of lactose-H^{+} symport. However, the free-energy differences between these states have not yet been reported in the literature. Here, we analyzed the biochemical structure of each state and determined a range of possible values for each one of the five free-energy variations. Then, using the Metropolis algorithm in a nonhomogeneous random walk model, we tested all the possible combinations with these values to find the free-energy curve that best reproduces the dynamics of LacY. The agreement between our model predictions and the experimental data suggests that our free-energy curve is appropriate for describing the lactose-H^{+} symport. We found not only this curve, but also the time of occupancy of the permease at each conformation. In addition, we paved the way in this work to solve an open question related to this transport mechanism, which is the importance of protonation for lactose binding.
Escherichia coli/enzymology , Membrane Transport Proteins/metabolism , Models, Biological , Biological Transport , Lactose/metabolism
Introduction The importance of our study lies in the fact that we have demonstrated the occurrence of mechanical dysfunction within polypoid tissues, which promotes the development of polyps in the nasal cavity. Objective To change the paradigm of nasal polyposis (NP). In this new conception, the chronic nasal inflammatory process that occurs in response to allergies, to pollution, to changes in the epithelial barrier, or to other factors is merely the trigger of the development of the disease in individuals with a genetic predisposition to an abnormal tissue remodeling process, which leads to a derangement of the mechanical properties of the nasal mucosa and, consequently, allows it to grow unchecked. Data Synthesis We propose a fundamentally new approach to intervening in the pathological process of NP, addressing biomechanical properties, fluid dynamics, and the concept of surface tension. Conclusion The incorporation of biomechanical knowledge into our understanding of NP provides a new perspective to help elucidate the physiology and the pathology of nasal polyps, and new avenues for the treatment and cure of NP.
Although redox processes closely interplay with mechanoresponses to control vascular remodeling, redox pathways coupling mechanostimulation to cellular cytoskeletal organization remain unclear. The peri/epicellular pool of protein disulfide isomerase-A1 (pecPDIA1) supports postinjury vessel remodeling. Using distinct models, we investigated whether pecPDIA1 could work as a redox-dependent organizer of cytoskeletal mechanoresponses. In vascular smooth muscle cells (VSMCs), pecPDIA1 immunoneutralization impaired stress fiber assembly in response to equibiaxial stretch and, under uniaxial stretch, significantly perturbed cell repositioning perpendicularly to stretch orientation. During cyclic stretch, pecPDIA1 supported thiol oxidation of the known mechanosensor ß1-integrin and promoted polarized compartmentalization of sulfenylated proteins. Using traction force microscopy, we showed that pecPDIA1 organizes intracellular force distribution. The net contractile moment ratio of platelet-derived growth factor-exposed to basal VSMCs decreased from 0.90 ± 0.09 (IgG-exposed controls) to 0.70 ± 0.08 after pecPDI neutralization ( P < 0.05), together with an enhanced coefficient of variation for distribution of force modules, suggesting increased noise. Moreover, in a single cell model, pecPDIA1 neutralization impaired migration persistence without affecting total distance or velocity, whereas siRNA-mediated total PDIA1 silencing disabled all such variables of VSMC migration. Neither expression nor total activity of the master mechanotransmitter/regulator RhoA was affected by pecPDIA1 neutralization. However, cyclic stretch-induced focal distribution of membrane-bound RhoA was disrupted by pecPDI inhibition, which promoted a nonpolarized pattern of RhoA/caveolin-3 cluster colocalization. Accordingly, FRET biosensors showed that pecPDIA1 supports localized RhoA activity at cell protrusions versus perinuclear regions. Thus, pecPDI acts as a thiol redox-dependent organizer and noise reducer mechanism of cytoskeletal repositioning, oxidant generation, and localized RhoA activation during a variety of VSMC mechanoresponses. NEW & NOTEWORTHY Effects of a peri/epicellular pool of protein disulfide isomerase-A1 (pecPDIA1) during mechanoregulation in vascular smooth muscle cells (VSMCs) were highlighted using approaches such as equibiaxial and uniaxial stretch, random single cell migration, and traction force microscopy. pecPDIA1 regulates organization of the cytoskeleton and minimizes the noise of cell alignment, migration directionality, and persistence. pecPDIA1 mechanisms involve redox control of ß1-integrin and localized RhoA activation. pecPDIA1 acts as a novel organizer of mechanoadaptation responses in VSMCs.
Adaptation, Physiological/physiology , Cytoskeleton/physiology , Myocytes, Smooth Muscle/physiology , Protein Disulfide-Isomerases/physiology , Actin Cytoskeleton/physiology , Animals , Biomechanical Phenomena , Cell Movement , Cells, Cultured , Gene Silencing , Integrin beta1/metabolism , Muscle, Smooth, Vascular/metabolism , Oxidants/metabolism , Pressoreceptors , Protein Disulfide-Isomerases/genetics , Rabbits , rhoA GTP-Binding Protein/metabolism
Introduction: The importance of our study lies in the fact that we have demonstrated the occurrence ofmechanical dysfunction within polypoid tissues, which promotes the development of polyps in the nasal cavity. Objective: To change the paradigm of nasal polyposis (NP). In this new conception, the chronic nasal inflammatory process that occurs in response to allergies, to pollution, to changes in the epithelial barrier, or to other factors is merely the trigger of the development of the disease in individuals with a genetic predisposition to an abnormal tissue remodeling process, which leads to a derangement of the mechanical properties of the nasal mucosa and, consequently, allows it to grow unchecked. Data: Synthesis We propose a fundamentally new approach to intervening in the pathological process of NP, addressing biomechanical properties, fluid dynamics, and the concept of surface tension. Conclusion: The incorporation of biomechanical knowledge into our understanding of NP provides a new perspective to help elucidate the physiology and the pathology of nasal polyps, and new avenues for the treatment and cure of NP (AU)
Humans , Nasal Polyps/physiopathology , Nasal Polyps/pathology , Inflammation/physiopathology , Sinusitis/physiopathology , Biomechanical Phenomena , Brazil , Flow Mechanics , Chronic Disease , Edema/physiopathology , Extracellular Matrix/pathology , Hydrostatic Pressure , Nasal Mucosa/physiopathology , Nasal Mucosa/pathology
Vascular smooth muscle cells (VSMCs) are essential components that keep the tonus of the arterial network, which is the channel used to conduct the blood from the heart to the peripheral areas of the body. It is known that mechanical and architectural changes in VSMCs may lead to functional modifications in the cardiovascular system; therefore, the quantitative characterization of these changes can help to elucidate questions that remain unclear in pathological situations, such as hypertension, vasospasm, vascular hypertrophy, and atherosclerosis. In this work, we have developed a new framework of image processing using the Sobel operator, associated with statistical analysis, to determine the degree of local alignment of actin filaments, which we found to be directly related with the distensibility of the arterial wall. We have also compared these results with the rigidity of the cytoskeleton of VSMCs. The results suggest that the alignment degree increases from peripheral arteries, such as carotid and femoral, to central arteries, as well coronary and thoracic aorta, which can indicate that the level of local alignment of the actin fibers in VSMCs is related with the mechanical behavior of the arterial wall. © 2018 International Society for Advancement of Cytometry.
Image Processing, Computer-Assisted/methods , Microscopy, Confocal/methods , Myocytes, Smooth Muscle/ultrastructure , Actin Cytoskeleton/ultrastructure , Animals , Swine
Neonatal cardiomyocytes are instrumental for disease modeling, but the effects of different cell extraction methods on basic cell biological processes remain poorly understood. We assessed the influence of two popular methods to extract rat neonatal cardiomyocytes, Pre-plating (PP), and Percoll (PC) on cell structure, metabolism, and function. Cardiomyocytes obtained from PP showed higher gene expression for troponins, titin, and potassium and sodium channels compared to PC. Also, PP cells displayed higher levels of troponin I protein. Cells obtained from PC displayed higher lactate dehydrogenase activity and lactate production than PP cells, indicating higher anaerobic metabolism after 8 days of culture. In contrast, reactive oxygen species levels were higher in PP cells as indicated by ethidium and hydroxyethidium production. Consistent with these data, protein nitration was higher in PP cells, as well as nitrite accumulation in cell medium. Moreover, PP cells showed higher global intracellular calcium under basal and 1 mM isoprenaline conditions. In a calcium-transient assessment under electrical stimulation (0.5 Hz), PP cells displayed higher calcium amplitude than cardiomyocytes obtained from PC and using a traction force microscope technique we observed that PP cardiomyocytes showed the highest relaxation. Collectively, we demonstrated that extraction methods influence parameters related to cell structure, metabolism, and function. Overall, PP derived cells are more active and mature than PC cells, displaying higher contractile function and generating more reactive oxygen species. On the other hand, PC derived cells display higher anaerobic metabolism, despite comparable high yields from both protocols.
Calcium/metabolism , Myocytes, Cardiac/cytology , Troponin I/genetics , Animals , Animals, Newborn , Cells, Cultured , Cytoplasm/genetics , Isoproterenol/pharmacology , Myocytes, Cardiac/physiology , Rats , Reactive Oxygen Species
BACKGROUND: Neurally Adjusted Ventilatory Assist (NAVA) is a proportional ventilatory mode that uses the electrical activity of the diaphragm (EAdi) to offer ventilatory assistance in proportion to patient effort. NAVA has been increasingly used for critically ill patients, but it has not been evaluated during spontaneous breathing trials (SBT). We designed a pilot trial to assess the feasibility of using NAVA during SBTs, and to compare the breathing pattern and patient-ventilator asynchrony of NAVA with Pressure Support (PSV) during SBTs. METHODS: We conducted a crossover trial in the ICU of a university hospital in Brazil and included mechanically ventilated patients considered ready to undergo an SBT on the day of the study. Patients underwent two SBTs in randomized order: 30 min in PSV of 5 cmH2O or NAVA titrated to generate equivalent peak airway pressure (Paw), with a positive end-expiratory pressure of 5 cmH2O. The ICU team, blinded to ventilatory mode, evaluated whether patients passed each SBT. We captured flow, Paw and electrical activity of the diaphragm (EAdi) from the ventilator and used it to calculate respiratory rate (RR), tidal volume (VT), and EAdi. Detection of asynchrony events used waveform analysis and we calculated the asynchrony index as the number of asynchrony events divided by the number of neural cycles. RESULTS: We included 20 patients in the study. All patients passed the SBT in PSV, and three failed the SBT in NAVA. Five patients were reintubated and the extubation failure rate was 25% (95% CI 9-49%). Respiratory parameters were similar in the two modes: VT = 6.1 (5.5-6.5) mL/Kg in NAVA vs. 5.5 (4.8-6.1) mL/Kg in PSV (p = 0.076) and RR = 27 (17-30) rpm in NAVA vs. 26 (20-30) rpm in PSV, p = 0.55. NAVA reduced AI, with a median of 11.5% (4.2-19.7) compared to 24.3% (6.3-34.3) in PSV (p = 0.033). CONCLUSIONS: NAVA reduces patient-ventilator asynchrony index and generates a respiratory pattern similar to PSV during SBTs. Patients considered ready for mechanical ventilation liberation may be submitted to an SBT in NAVA using the same objective criteria used for SBTs in PSV. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT01337271 ), registered April 12, 2011.
Interactive Ventilatory Support , Positive-Pressure Respiration , Ventilator Weaning/methods , Adult , Aged , Aged, 80 and over , Airway Extubation , Critical Illness , Cross-Over Studies , Diaphragm/physiopathology , Female , Humans , Intensive Care Units , Male , Middle Aged , Pilot Projects , Respiratory Rate , Simplified Acute Physiology Score , Single-Blind Method , Tidal Volume , Young Adult
BACKGROUND: In patients with post-extubation respiratory distress, delayed reintubation may worsen clinical outcomes. Objective measures of extubation failure at the bedside are lacking, therefore clinical parameters are currently used to guide the need of reintubation. Electrical activity of the diaphragm (EAdi) provides clinicians with valuable, objective information about respiratory drive and could be used to monitor respiratory effort. CASE PRESENTATION: We describe the case of a patient with Chronic Obstructive Pulmonary Disease (COPD), from whom we recorded EAdi during four different ventilatory conditions: 1) invasive mechanical ventilation, 2) spontaneous breathing trial (SBT), 3) unassisted spontaneous breathing, and 4) Noninvasive Positive Pressure Ventilation (NPPV). The patient had been intubated due to an exacerbation of COPD, and after four days of mechanical ventilation, she passed the SBT and was extubated. Clinical signs of respiratory distress were present immediately after extubation, and EAdi increased compared to values obtained during mechanical ventilation. As we started NPPV, EAdi decreased substantially, indicating muscle unloading promoted by NPPV, and we used the EAdi signal to monitor respiratory effort during NPPV. Over the next three days, she was on NPPV for most of the time, with short periods of spontaneous breathing. EAdi remained considerably lower during NPPV than during spontaneous breathing, until the third day, when the difference was no longer clinically significant. She was then weaned from NPPV and discharged from the ICU a few days later. CONCLUSION: EAdi monitoring during NPPV provides an objective parameter of respiratory drive and respiratory muscle unloading and may be a useful tool to guide post-extubation ventilatory support. Clinical studies with continuous EAdi monitoring are necessary to clarify the meaning of its absolute values and changes over time.
Diaphragm/physiopathology , Noninvasive Ventilation , Positive-Pressure Respiration , Respiratory Insufficiency/physiopathology , Respiratory Insufficiency/therapy , Airway Extubation/adverse effects , Female , Humans , Middle Aged , Monitoring, Physiologic , Pulmonary Disease, Chronic Obstructive/therapy , Respiratory Insufficiency/etiology
The cytoskeleton (CSK) is a tensed fiber framework that supports, shapes and stabilizes the cell. The CSK is in a constant state of remodeling, moreover, which is an active non-equilibrium thermodynamic process. We report here that cytoskeletal remodeling involves reconfigurations that are not only sudden but also are transmitted to great distances within the cell in a fashion reminiscent of quakes in the Earth's crust. Remarkably, these events in the cell conform both qualitatively and quantitatively to empirical laws typical of earthquakes, including hierarchical fault structures, cumulative energy distributions following the Gutenberg-Richter law, and rate of after-shocks following Omori's law. While it is well-established that remodeling and stabilization of the cytoskeleton are non-equilibrium process, these new unanticipated observations establish that these processes are also remarkably non-local and strongly cooperative.
Cytoskeleton/physiology , Myocytes, Smooth Muscle/cytology , Cells, Cultured , Humans , Thermodynamics
Diesel exhaust particles (DEPs) from diesel engines produce adverse alterations in cells of the airways by activating intracellular signaling pathways and apoptotic gene overexpression, and also by influencing metabolism and cytoskeleton changes. This study used human bronchial epithelium cells (BEAS-2B) in culture and evaluates their exposure to DEPs (15ug/mL for 1 and 2 h) in order to determine changes to cell rheology (viscoelasticity) and gene expression of the enzymes involved in oxidative stress, apoptosis, and cytotoxicity. BEAS-2B cells exposed to DEPs were found to have a significant loss in stiffness, membrane stability, and mitochondrial activity. The genes involved in apoptosis [B cell lymphoma 2 (BCL-2 and caspase-3)] presented inversely proportional expressions (p = 0.05, p = 0.01, respectively), low expression of the genes involved in antioxidant responses [SOD1 (superoxide dismutase 1); SOD2 (superoxide dismutase 2), and GPx (glutathione peroxidase) (p = 0.01)], along with an increase in cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) (p = 0.01). These results suggest that alterations in cell rheology and cytotoxicity could be associated with oxidative stress and imbalance between pro- and anti-apoptotic genes.
Antioxidants/metabolism , Apoptosis/drug effects , Bronchi/drug effects , Epithelial Cells/drug effects , Gene Expression/drug effects , Particulate Matter/toxicity , Vehicle Emissions/toxicity , Apoptosis/genetics , Bronchi/metabolism , Bronchi/pathology , Caspase 3/genetics , Caspase 3/metabolism , Cell Line , Cell Survival/drug effects , Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP1A1/metabolism , Epithelial Cells/metabolism , Epithelial Cells/pathology , Glutathione Peroxidase/genetics , Glutathione Peroxidase/metabolism , Humans , Oxidative Stress/drug effects , Oxidative Stress/genetics , Particle Size , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Rheology
