Publications

Human pluripotent stem cell -derived kidney organoids offer unprecedented opportunities for studying polycystic kidney disease (PKD), which still has no effective cure. Here, we developed both in vitro and in vivo organoid models of PKD that manifested tubular injury and aberrant upregulation of renin-angiotensin aldosterone system. Single -cell analysis revealed that a myriad of metabolic changes occurred during cystogenesis, including defective autophagy. Experimental activation of autophagy via ATG5 overexpression or primary cilia ablation significantly inhibited cystogenesis in PKD kidney organoids. Employing the organoid xenograft model of PKD, which spontaneously developed tubular cysts, we demonstrate that minoxidil, a potent autophagy activator and an FDA -approved drug, effectively attenuated cyst formation in vivo. This in vivo organoid model of PKD will enhance our capability to discover novel disease mechanisms and validate candidate drugs for clinical translation.

JTD Keywords: Adenylate kinase, Adult, Animal cell, Animal experiment, Animal model, Animal tissue, Article, Autophagosome, Autophagy, Autophagy (cellular), Autosomal-dominant, Calcium homeostasis, Cilia, Cilium, Cohort analysis, Controlled study, Cyclic amp, Disease, Dominant polycystic kidney, Enzyme linked immunosorbent assay, Epithelium, Exon, Expression, Female, Food and drug administration, Framework, Generation, Growth, Hepatitis a virus cellular receptor 1, Human, Human cell, Humans, Immunohistochemistry, In vitro study, In vivo study, Kidney, Kidney organoid, Kidney polycystic disease, Male, Minoxidil, Mouse, Mutations, Nonhuman, Organoid, Organoids, Platelet derived growth factor beta receptor, Pluripotent stem-cells, Polycystic kidney diseases, Protein kinase lkb1, Renin, Sequestosome 1, Single cell analysis, Single cell rna seq, Small nuclear rna, Tunel assay, Upregulation, Western blotting, Whole exome sequencing

We aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography.Severe OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency-domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed.We considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52-64.5); females 25%; AHI (apnea-hypopnea index) 84.4 (76.1-93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001).Obstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.© The Author(s) 2023. Published by Oxford University Press on behalf of Sleep Research Society.

JTD Keywords: cerebral hemodynamics, desaturation, diffuse correlation spectroscopy, duration, hypopnea, hypoxemia, near-infrared spectroscopy, optical pathlength, oxygenation, severity, sleep disorder, spectroscopy, tissue, Adult, Airway obstruction, Apnea hypopnea index, Arterial oxygen saturation, Article, Blood oxygen tension, Blood-flow, Brain blood flow, Brain cortex, Cerebral hemodynamics, Controlled study, Diffuse correlation spectroscopy, Disease severity, Female, Frequency, Frontal lobe, Heart rate, Hemodynamics, Hemoglobin, Hemoglobin determination, Human, Humans, Major clinical study, Male, Near infrared spectroscopy, Near-infrared spectroscopy, Obstructive sleep apnea, Oxygen, Periodicity, Polysomnography, Sleep apnea syndromes, Sleep apnea, obstructive, Sleep disorder, Spectroscopy, near-infrared

Effective inhibition of sperm motility using a spermicide can be a promising approach in developing non-invasive male contraceptive agents. Copper is known to have contraceptive properties and has been used clinically for decades as intrauterine contraceptive devices (IUDs) for contraception in females. Beyond that, the spermicidal use of copper is not explored much further, even though its use can also subdue the harmful effects caused by the hormonal female contraceptive agents on the environment. Herein, the size, concentration, and time-dependent in vitro inhibition of bovine spermatozoa by copper microparticles are studied. The effectivity in inhibiting sperm motility is correlated with the amount of Cu2+ ions released by the particles during incubation. The copper particles cause direct suppression of sperm motility and viability upon incubation and thereby show potential as sperm-inhibiting, hormone-free candidate for male contraception. In addition, biocompatibility tests using a cervical cell line help optimizing the size and concentration of the copper particles for the best spermicidal action while avoiding toxicity to the surrounding tissue.

JTD Keywords: Bovine spermatozoa, Clinical-trial, Copper, Human-spermatozoa, Ions, Male contraception, Metallic copper, Microparticles, Progestins, Sperm motility, Sperm viability, Spermicide, Viability

Underpowered trials risk inaccurate results. Recruitment to stroke rehabilitation randomised controlled trials (RCTs) is often a challenge. Statistical simulations offer an important opportunity to explore the adequacy of sample sizes in the context of specific outcome measures. We aimed to examine and compare the adequacy of stroke rehabilitation RCT sample sizes using the Barthel Index (BI) or modified Rankin Scale (mRS) as primary outcomes.We conducted computer simulations using typical experimental event rates (EER) and control event rates (CER) based on individual participant data (IPD) from stroke rehabilitation RCTs. Event rates are the proportion of participants who experienced clinically relevant improvements in the RCT experimental and control groups. We examined minimum sample size requirements and estimated the number of participants required to achieve a number needed to treat within clinically acceptable boundaries for the BI and mRS.We secured 2350 IPD (18 RCTs). For a 90% chance of statistical accuracy on the BI a rehabilitation RCT would require 273 participants per randomised group. Accurate interpretation of effect sizes would require 1000s of participants per group. Simulations for the mRS were not possible as a clinically relevant improvement was not detected when using this outcome measure.Stroke rehabilitation RCTs with large sample sizes are required for accurate interpretation of effect sizes based on the BI. The mRS lacked sensitivity to detect change and thus may be unsuitable as a primary outcome in stroke rehabilitation trials.Copyright © 2021 Elsevier Inc. All rights reserved.

JTD Keywords:  , barthel index, design, increasing value, modified rankin scale, randomised controlled trials, recruitment, reducing waste, reliability, sample size calculations, simulations, stroke rehabilitation, Adult, Article, Barthel index, Calculation, Computer simulation, Controlled study, Effect size, Female, Human, Human experiment, Major clinical study, Male, Modified rankin scale, Numbers needed to treat, Outcome assessment, Randomised controlled trials, Randomized controlled trial, Randomized controlled-trials, Rankin scale, Recruitment, Rehabilitation, Sample size, Sample size calculations, Simulations, Stroke rehabilitation

The mechanical signals sensed by the alveolar cells through the changes in the local matrix stiffness of the extracellular matrix (ECM) are determinant for regulating cellular functions. Therefore, the study of the mechanical response of lung tissue becomes a fundamental aspect in order to further understand the mechanosensing signals perceived by the cells in the alveoli. This study is focused on the development of a finite element (FE) model of a decellularized rat lung tissue strip, which reproduces accurately the mechanical behaviour observed in the experiments by means of a tensile test. For simulating the complex structure of the lung parenchyma, which consists of a heterogeneous and non-uniform network of thin-walled alveoli, a 3D model based on a Voronoi tessellation is developed. This Voronoi-based model is considered very suitable for recreating the geometry of cellular materials with randomly distributed polygons like in the lung tissue. The material model used in the mechanical simulations of the lung tissue was characterized experimentally by means of AFM tests in order to evaluate the lung tissue stiffness on the micro scale. Thus, in this study, the micro (AFM test) and the macro scale (tensile test) mechanical behaviour are linked through the mechanical simulation with the 3D FE model based on Voronoi tessellation. Finally, a micro-mechanical FE-based model is generated from the Voronoi diagram for studying the stiffness sensed by the alveolar cells in function of two independent factors: the stretch level of the lung tissue and the geometrical position of the cells on the extracellular matrix (ECM), distinguishing between pneumocyte type I and type II. We conclude that the position of the cells within the alveolus has a great influence on the local stiffness perceived by the cells. Alveolar cells located at the corners of the alveolus, mainly type II pneumocytes, perceive a much higher stiffness than those located in the flat areas of the alveoli, which correspond to type I pneumocytes. However, the high stiffness, due to the macroscopic lung tissue stretch, affects both cells in a very similar form, thus no significant differences between them have been observed. © 2021 The Authors

JTD Keywords: rat, scaffolds, stiffness, Afm, Animal cell, Animal experiment, Animal model, Animal tissue, Article, Biological organs, Cell function, Cells, Computational geometry, Cytology, Extracellular matrices, Extracellular matrix, Extracellular-matrix, Geometry, High stiffness, Human, Lung alveolus cell type 1, Lung alveolus cell type 2, Lung parenchyma, Lung tissue, Male, Mechanical behavior, Mechanical modeling, Mechanical simulations, Mechanosensing, Model-based opc, Nonhuman, Physical model, Rat, Rigidity, Stiffness, Stiffness matrix, Tensile testing, Thin walled structures, Three dimensional finite element analysis, Tissue, Type ii, Voronoi tessellations

Introduction: After a stroke, a wide range of deficits can occur with varying onset latencies. As a result, assessing impairment and recovery are enormous challenges in neurorehabilitation. Although several clinical scales are generally accepted, they are time-consuming, show high inter-rater variability, have low ecological validity, and are vulnerable to biases introduced by compensatory movements and action modifications. Alternative methods need to be developed for efficient and objective assessment. In this study, we explore the potential of computer-based body tracking systems and classification tools to estimate the motor impairment of the more affected arm in stroke patients. Methods: We present a method for estimating clinical scores from movement parameters that are extracted from kinematic data recorded during unsupervised computer-based rehabilitation sessions. We identify a number of kinematic descriptors that characterise the patients' hemiparesis (e.g., movement smoothness, work area), we implement a double-noise model and perform a multivariate regression using clinical data from 98 stroke patients who completed a total of 191 sessions with RGS. Results: Our results reveal a new digital biomarker of arm function, the Total Goal-Directed Movement (TGDM), which relates to the patients work area during the execution of goal-oriented reaching movements. The model's performance to estimate FM-UE scores reaches an accuracy of R-2: 0.38 with an error (sigma: 12.8). Next, we evaluate its reliability (r = 0.89 for test-retest), longitudinal external validity (95% true positive rate), sensitivity, and generalisation to other tasks that involve planar reaching movements (R-2: 0.39). The model achieves comparable accuracy also for the Chedoke Arm and Hand Activity Inventory (R-2: 0.40) and Barthel Index (R-2: 0.35). Conclusions: Our results highlight the clinical value of kinematic data collected during unsupervised goal-oriented motor training with the RGS combined with data science techniques, and provide new insight into factors underlying recovery and its biomarkers.

JTD Keywords: interactive feedback, motion classification, motion sensing, multivariate regression, posture monitoring, rehabilitation, stroke, Adult, Aged, Analytic method, Arm movement, Article, Barthel index, Brain hemorrhage, Cerebrovascular accident, Chedoke arm and hand activity inventory, Clinical protocol, Cognitive defect, Computer analysis, Controlled study, Convergent validity, Correlation coefficient, Disease severity, External validity, Female, Fugl meyer assessment for the upper extremity, Functional assessment, Functional status assessment, General health status assessment, Hemiparesis, Human, Interactive feedback, Ischemic stroke, Kinematics, Major clinical study, Male, Mini mental state examination, Motion classification, Motion sensing, Motor analog scale, Movement, Multivariate regression, Muscle function, Posture monitoring, Probability, Recovery, Rehabilitation, Reliability, Retrospective study, Stroke, Stroke patient, Test retest reliability, Therapy, Total goal directed movement, Upper extremities, Upper limb, Upper-limb, Wolf motor function test

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO(2) sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications.

JTD Keywords: electrochemical biosensor, implantable sensor, in vivo validation, ischemia detection, tissue and vascular monitoring, Animal experiment, Animal model, Animal tissue, Article, Blood-gases, Brain, Classification, Controlled study, Diagnosis, Doppler, Early diagnosis, Electrochemical analysis, Electrochemical biosensor, Ewe, Feasibility study, Female, Fetus, Fetus disease, Fetus monitoring, Gestational age, Hypoxemia, Iliac artery, Implantable sensor, In vivo validation, Intrauterine growth restriction, Intrauterine growth retardation, Ischemia detection, Leg muscle, Management, Nonhuman, Oxygen consumption, Ph, Ph and oxygen detection, Ph measurement, Process optimization, Sheep, Tissue and vascular monitoring, Umbilical-cord occlusion

The unique ability to identify one's own body and experience it as one's own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. Evidence based on Rubber Hand Illusion (RHI) paradigms has demonstrated that body ownership is a product of reception and integration of self and externally generated multisensory information, feedforward and feedback processing of sensorimotor signals, and prior knowledge about the body. Crucially, however, these designs commonly involve the processing of proximal modalities while the contribution of distal sensory signals to the experience of ownership remains elusive. Here we propose that, like any robust percept, body ownership depends on the integration and prediction across all sensory modalities, including distal sensory signals pertaining to the environment. To test our hypothesis, we created an embodied goal-oriented Virtual Air Hockey Task, in which participants were to hit a virtual puck into a goal. In two conditions, we manipulated the congruency of distal multisensory cues (auditory and visual) while preserving proximal and action-driven signals entirely predictable. Compared to a fully congruent condition, our results revealed a significant decrease on three dimensions of ownership evaluation when distal signals were incongruent, including the subjective report as well as physiological and kinematic responses to an unexpected threat. Together, these findings support the notion that the way we represent our body is contingent upon all the sensory stimuli, including distal and action-independent signals. The present data extend the current framework of body ownership and may also find applications in rehabilitation scenarios.

Cell response to force regulates essential processes in health and disease. However, the fundamental mechanical variables that cells sense and respond to remain unclear. Here we show that the rate of force application (loading rate) drives mechanosensing, as predicted by a molecular clutch model. By applying dynamic force regimes to cells through substrate stretching, optical tweezers, and atomic force microscopy, we find that increasing loading rates trigger talin-dependent mechanosensing, leading to adhesion growth and reinforcement, and YAP nuclear localization. However, above a given threshold the actin cytoskeleton softens, decreasing loading rates and preventing reinforcement. By stretching rat lungs in vivo, we show that a similar phenomenon may occur. Our results show that cell sensing of external forces and of passive mechanical parameters (like tissue stiffness) can be understood through the same mechanisms, driven by the properties under force of the mechanosensing molecules involved. Cells sense mechanical forces from their environment, but the precise mechanical variable sensed by cells is unclear. Here, the authors show that cells can sense the rate of force application, known as the loading rate, with effects on YAP nuclear localization and cytoskeletal stiffness remodelling.

JTD Keywords: Actin cytoskeleton, Actin filament, Actin-filament, Adhesion, Animal, Animals, Atomic force microscopy, Breathing, Cell, Cell adhesion, Cell culture, Cell nucleus, Cells, cultured, Cytoplasm, Extracellular-matrix, Fibroblast, Fibroblasts, Fibronectin, Frequency, Gene knockdown, Gene knockdown techniques, Genetics, Germfree animal, Integrin, Intracellular signaling peptides and proteins, Knockout mouse, Lung, Male, Mechanotransduction, Mechanotransduction, cellular, Metabolism, Mice, Mice, knockout, Microscopy, atomic force, Mouse, Optical tweezers, Paxillin, Physiology, Primary cell culture, Pxn protein, mouse, Rat, Rats, Rats, sprague-dawley, Respiration, Signal peptide, Softening, Specific pathogen-free organisms, Sprague dawley rat, Stress, Substrate, Substrate rigidity, Talin, Talin protein, mouse, Tln2 protein, mouse, Traction, Transmission, Ultrastructure, Yap1 protein, rat

Goel and colleagues show that CDK4/6 inhibition induces global chromatin changes mediated by AP-1 factors, which mediate key biological and clinical effects in breast cancer. Pharmacologic inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6) were designed to induce cancer cell cycle arrest. Recent studies have suggested that these agents also exert other effects, influencing cancer cell immunogenicity, apoptotic responses and differentiation. Using cell-based and mouse models of breast cancer together with clinical specimens, we show that CDK4/6 inhibitors induce remodeling of cancer cell chromatin characterized by widespread enhancer activation, and that this explains many of these effects. The newly activated enhancers include classical super-enhancers that drive luminal differentiation and apoptotic evasion, as well as a set of enhancers overlying endogenous retroviral elements that are enriched for proximity to interferon-driven genes. Mechanistically, CDK4/6 inhibition increases the level of several activator protein-1 transcription factor proteins, which are in turn implicated in the activity of many of the new enhancers. Our findings offer insights into CDK4/6 pathway biology and should inform the future development of CDK4/6 inhibitors.

JTD Keywords: Abemaciclib, Androgen receptor, Animal experiment, Animal model, Animal tissue, Apoptosis, Article, Breast cancer, C-jun, Cancer cell, Carcinoembryonic antigen related cell adhesion molecule 1, Caspase 3, Cell cycle arrest, Cells, Chromatin, Chromatin immunoprecipitation, Controlled study, Cyclin dependent kinase 4, Cyclin dependent kinase 6, Dna damage, Epidermal growth factor receptor 2, Estrogen receptor, Female, Flow cytometry, Fulvestrant, Hla drb1 antigen, Human, Human cell, Immunoblotting, Immunogenicity, Immunoprecipitation, Interferon, Luciferase assay, Mcf-7 cell line, Mda-mb-231 cell line, Microarray analysis, Morphogenesis, Mouse, Nonhuman, Palbociclib, Protein, Protein expression, Rb, Resistance, Rna polymerase ii, Rna sequence, Selective-inhibition, Senescence, Short tandem repeat, Signal transduction, Tamoxifen, Transcription elongation, Transcription factor, Transcription factor ap 1, Transcriptome, Tumor biopsy, Tumor differentiation, Tumor spheroid, Tumor xenograft, Vinculin, Whole exome sequencing

Background: Heart failure (HF) – a very prevalent disease with high morbidity and mortality – usually presents with diastolic dysfunction. Although post-menopause women are at increased risk of HF and diastolic dysfunction, poor attention has been paid to clinically and experimentally investigate this group of patients. Specifically, whether myocardial stiffness is affected by menopause is unknown. Aim: To investigate whether loss of female sexual hormones modifies the Young’s modulus (E) of left ventricular (LV) myocardial tissue in a mouse model of menopause induced by ovariectomy (OVX). Methods: After 6 months of bilateral OVX, eight mice were sacrificed, fresh LV myocardial strips were prepared (∼8 × 1 × 1 mm), and their passive stress–stretch relationship was measured. E was computed by exponential fitting of the stress–stretch relationship. Subsequently, to assess the relative role of cellular and extracellular matrix components in determining OVX-induced changes in E, the tissues strips were decellularized and subjected to the same stretching protocol to measure E. A control group of eight sham-OVX mice was simultaneously studied. Results: E (kPa; m ± SE) in OVX mice was ∼twofold lower than in controls (11.7 ± 1.8 and 22.1 ± 4.4, respectively; p < 0.05). No significant difference between groups was found in E of the decellularized tissue (31.4 ± 12.05 and 40.9 ± 11.5, respectively; p = 0.58). Conclusion: Loss of female sexual hormones in an OVX model induces a reduction in the passive stiffness of myocardial tissue, suggesting that active relaxation should play a counterbalancing role in diastolic dysfunction in post-menopausal women with HF.

JTD Keywords: Decellularized tissue, Female hormones, Heart tissue, Ovariectomy, Stress-strain

Heparin had been demonstrated to have antimalarial activity and specific binding affinity for Plasmodium-infected red blood cells (pRBCs) vs. non-infected erythrocytes. Here we have explored if both properties could be joined into a drug delivery strategy where heparin would have a dual role as antimalarial and as a targeting element of drug-loaded nanoparticles. Confocal fluorescence and transmission electron microscopy data show that after 30. min of being added to living pRBCs fluorescein-labeled heparin colocalizes with the intracellular parasites. Heparin electrostatically adsorbed onto positively charged liposomes containing the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane and loaded with the antimalarial drug primaquine was capable of increasing three-fold the activity of encapsulated drug in Plasmodium falciparum cultures. At concentrations below those inducing anticoagulation of mouse blood in vivo, parasiticidal activity was found to be the additive result of the separate activities of free heparin as antimalarial and of liposome-bound heparin as targeting element for encapsulated primaquine. From the Clinical Editor: Malaria remains an enormous global public health concern. In this study, a novel functionalized heparin formulation used as drug delivery agent for primaquine was demonstrated to result in threefold increased drug activity in cell cultures, and in a murine model it was able to provide these benefits in concentrations below what would be required for anticoagulation. Further studies are needed determine if this approach is applicable in the human disease as well.

JTD Keywords: Heparin, Liposomes, Malaria, Plasmodium, Targeted drug delivery, Heparin, Malaria, Plasmodium, Red blood cell, Targeted drug delivery, Liposomes, 1,2 dioleoyl 3 trimethylammoniopropane, fluorescein, heparin, liposome, nanoparticle, primaquine, adsorption, animal experiment, anticoagulation, antimalarial activity, Article, binding affinity, confocal microscopy, controlled study, drug targeting, encapsulation, erythrocyte, female, fluorescence microscopy, human, human cell, in vivo study, liposomal delivery, mouse, nonhuman, Plasmodium falciparum, transmission electron microscopy

Study Objectives: To test the hypotheses that brain oxygen partial pressure (PtO2) in response to obstructive apneas changes with age and that it might lead to different levels of cerebral tissue oxidative stress. Design: Prospective controlled animal study. Setting: University laboratory. Participants: Sixty-four male Wistar rats: 32 young (3 mo old) and 32 aged (18 mo). Interventions: Protocol 1: Twenty-four animals were subjected to obstructive apneas (50 apneas/h, lasting 15 sec each) or to sham procedure for 50 min. Protocol 2: Forty rats were subjected to obstructive apneas or sham procedure for 4 h. Measurements and Results: Protocol 1: Real-time PtO2 measurements were performed using a fast-response oxygen microelectrode. During successive apneas cerebral cortex PtO2 presented a different pattern in the two age groups; there was a fast increase in young rats, whereas it remained without significant changes between the beginning and the end of the protocol in the aged group. Protocol 2: Brain oxidative stress assessed by lipid peroxidation increased after apneas in young rats (1.34 ± 0.17 nmol/mg of protein) compared to old ones (0.63 ± 0.03 nmol/mg), where a higher expression of antioxidant enzymes was observed. Conclusions: The results suggest that brain oxidative stress in aged rats is lower than in young rats in response to recurrent apneas, mimicking obstructive sleep apnea. This could be due to the different PtO2 response observed between age groups and the increased antioxidant expression in aged rats.

JTD Keywords: Aging, Animal model, Obstructive apnea, Oxidative stress, Tissue oxygenation, antioxidant, glutathione disulfide, aged, animal experiment, animal model, animal tissue, apnea, arterial oxygen saturation, article, brain cortex, brain oxygen tension, brain tissue, controlled study, groups by age, hypoxia, lipid peroxidation, male, nonhuman, oxidative stress, pressure, priority journal, rat

Lung disease models are useful to study how cell engraftment, proliferation and differentiation are modulated in lung bioengineering. The aim of this work was to characterize the local stiffness of decellularized lungs in aged and fibrotic mice. Mice (2- and 24-month old; 14 of each) with lung fibrosis (N=20) and healthy controls (N=8) were euthanized after 11 days of intratracheal bleomycin (fibrosis) or saline (controls) infusion. The lungs were excised, decellularized by a conventional detergent-based (sodium-dodecyl sulfate) procedure and slices of the acellular lungs were prepared to measure the local stiffness by means of atomic force microscopy. The local stiffness of the different sites in acellular fibrotic lungs was very inhomogeneous within the lung and increased according to the degree of the structural fibrotic lesion. Local stiffness of the acellular lungs did not show statistically significant differences caused by age. The group of mice most affected by fibrosis exhibited local stiffness that were ~2-fold higher than in the control mice: from 27.2±1.64 to 64.8±7.1. kPa in the alveolar septa, from 56.6±4.6 to 99.9±11.7. kPa in the visceral pleura, from 41.1±8.0 to 105.2±13.6. kPa in the tunica adventitia, and from 79.3±7.2 to 146.6±28.8. kPa in the tunica intima. Since acellular lungs from mice with bleomycin-induced fibrosis present considerable micromechanical inhomogeneity, this model can be a useful tool to better investigate how different degrees of extracellular matrix lesion modulate cell fate in the process of organ bioengineering from decellularized lungs.

JTD Keywords: Ageing, Atomic force microscopy, Decellularization, Lung fibrosis, Tissue engineering, Atomic force microscopy, Biological organs, Peptides, Sodium dodecyl sulfate, Sodium sulfate, Tissue engineering, Ageing, Decellularization, Extracellular matrices, Healthy controls, Inhomogeneities, Lung fibrosis, Micro-mechanical, Statistically significant difference, Mammals, bleomycin, adventitia, animal experiment, animal model, article, atomic force microscopy, bleomycin-induced pulmonary fibrosis, cell fate, controlled study, extracellular matrix, female, intima, lung alveolus, lung fibrosis, lung mechanics, mechanical probe, microenvironment, mouse, nonhuman, pleura, priority journal, rigidity, tissue engineering

Lung bioengineering using decellularized organ scaffolds is a potential alternative for lung transplantation. Clinical application will require donor scaffold sterilization. As gamma-irradiation is a conventional method for sterilizing tissue preparations for clinical application, the aim of this study was to evaluate the effects of lung scaffold sterilization by gamma irradiation on the mechanical properties of the acellular lung when subjected to the artificial ventilation maneuvers typical within bioreactors. Twenty-six mouse lungs were decellularized by a sodium dodecyl sulfate detergent protocol. Eight lungs were used as controls and 18 of them were submitted to a 31kGy gamma irradiation sterilization process (9 kept frozen in dry ice and 9 at room temperature). Mechanical properties of acellular lungs were measured before and after irradiation. Lung resistance (RL) and elastance (EL) were computed by linear regression fitting of recorded signals during mechanical ventilation (tracheal pressure, flow and volume). Static (Est) and dynamic (Edyn) elastances were obtained by the end-inspiratory occlusion method. After irradiation lungs presented higher values of resistance and elastance than before irradiation: RL increased by 41.1% (room temperature irradiation) and 32.8% (frozen irradiation) and EL increased by 41.8% (room temperature irradiation) and 31.8% (frozen irradiation). Similar increases were induced by irradiation in Est and Edyn. Scanning electron microscopy showed slight structural changes after irradiation, particularly those kept frozen. Sterilization by gamma irradiation at a conventional dose to ensure sterilization modifies acellular lung mechanics, with potential implications for lung bioengineering.

JTD Keywords: Gamma irradiation, Lung bioengineering, Lung decellularization, Organ scaffold, Pulmonary mechanics, Decellularization, Gamma irradiation, Mouse lung, Pulmonary mechanics, dodecyl sulfate sodium, animal tissue, Article, artificial ventilation, bioengineering, bioreactor, compliance (physical), controlled study, freezing, gamma irradiation, lung, lung mechanics, lung resistance, male, mouse, nonhuman, room temperature, scanning electron microscopy, tissue scaffold, trachea pressure

Lung decellularization is based on the use of physical, chemical, or enzymatic methods to break down the integrity of the cells followed by a treatment to extract the cellular material from the lung scaffold. The aim of this study was to characterize the mechanical changes throughout the different steps of lung decellularization process. Four lungs from mice (C57BL/6) were decellularized by using a conventional protocol based on sodium dodecyl sulfate. Lungs resistance (RL) and elastance (EL) were measured along decellularization steps and were computed by linear regression fitting of tracheal pressure, flow, and volume during mechanical ventilation. Transients differences found were more distinct in an intermediate step after the lungs were rinsed with deionized water and treated with 1% SDS, whereupon the percentage of variation reached approximately 80% for resistance values and 30% for elastance values. In conclusion, although a variation in extracellular matrix stiffness was observed during the decellularization process, this variation can be considered negligible overall because the resistance and elastance returned to basal values at the final decellularization step.

JTD Keywords: Lung bioengineering, Lung decellularization, Organ scaffold, dodecyl sulfate sodium, animal tissue, article, artificial ventilation, compliance (physical), controlled study, enzyme chemistry, extracellular matrix, female, flow, lung, lung decellularization, lung pressure, lung resistance, mouse, nonhuman, positive end expiratory pressure, priority journal, rigidity, tissue engineering, trachea pressure

Rat model of Obstructive Sleep Apnea (OSA) is a realistic approach for studying physiological mechanisms involved in sleep. Rats are usually anesthetized and autonomic nervous system (ANS) could be blocked. This study aimed to assess the effect of anesthesia on ANS activity during OSA episodes. Seven male Sprague-Dawley rats were anesthetized intraperitoneally with urethane (1g/kg). The experiments were conducted applying airway obstructions, simulating 15s-apnea episodes for 15 minutes. Five signals were acquired: respiratory pressure and flow, SaO2, ECG and photoplethysmography (PPG). In total, 210 apnea episodes were studied. Normalized power spectrum of Pulse Rate Variability (PRV) was analyzed in the Low Frequency (LF) and High Frequency (HF) bands, for each episode in consecutive 15s intervals (before, during and after the apnea). All episodes showed changes in respiratory flow and SaO₂ signal. Conversely, decreases in the amplitude fluctuations of PPG (DAP) were not observed. Normalized LF presented extremely low values during breathing (median=7,67%), suggesting inhibition of sympathetic system due to anesthetic effect. Subtle increases of LF were observed during apnea. HRV and PPG analysis during apnea could be an indirect tool to assess the effect and deep of anesthesia.

JTD Keywords: electrocardiography, fluctuations, medical disorders, medical signal detection, medical signal processing, neurophysiology, photoplethysmography, pneumodynamics, sleep, ECG, SaO₂ flow, SaO₂ signal, airway obstructions, amplitude fluctuations, anesthesia effects, anesthetized nervous system, autonomic evaluation, autonomic nervous system, breathing, heart rate variability, high-frequency bands, low-frequency bands, male Sprague-Dawley rats, normalized power spectrum, obstructive sleep apnea, photoplethysmography, physiological mechanisms, pulse rate variability, rat model, respiratory flow, respiratory pressure, signal acquisition, sympathetic system inhibition, time 15 min, time 15 s, Abstracts, Atmospheric modeling, Computational modeling, Electrocardiography, Rats, Resonant frequency

STUDY OBJECTIVES: To investigate whether noninvasive application of recurrent airway obstructions induces early release of mesenchymal stem cells into the circulating blood in a rat model of obstructive sleep apnea. DESIGN: Prospective controlled animal study. SETTING: University laboratory. PATIENTS OR PARTICIPANTS: Twenty male Sprague-Dawley rats (250-300 g). INTERVENTIONS: A specially designed nasal mask was applied to the anesthetized rats. Ten rats were subjected to a pattern of recurrent obstructive apneas (60 per hour, lasting 15 seconds each) for 5 hours. Ten anesthetized rats were used as controls. MEASUREMENTS AND RESULTS: Mesenchymal stem cells from the blood and bone marrow samples were isolated and cultured to count the total number of colony-forming unit fibroblasts (CFU-F) of adherent cells after 9 days in culture. The number of CFU-F from circulating blood was significantly (P = 0.02) higher in the rats subjected to recurrent obstructive apneas (5.00 +/- 1.16; mean +/- SEM) than in controls (1.70 +/- 0.72). No significant (P = 0.54) differences were observed in CFU-F from bone marrow. CONCLUSIONS: Application of a pattern of airway obstructions similar to those experienced by patients with sleep apnea induced an early mobilization of mesenchymal stem cells into circulating blood.

JTD Keywords: Adipocytes/cytology, Animals, Blood Cell Count, Bone Marrow Cells/ cytology, Cell Adhesion/physiology, Cell Count, Cell Differentiation/physiology, Cell Division/physiology, Disease Models, Animal, Fibroblasts/cytology, Male, Mesenchymal Stem Cells/ cytology, Osteocytes/cytology, Rats, Rats, Sprague-Dawley, Sleep Apnea, Obstructive/ blood, Stem Cells/cytology

In this paper we compare three different spectral estimation techniques for the classification of mental tasks. These techniques are the standard periodogram, the Welch periodogram and the Burg method, applied to electroencephalographic (EEG) signals. For each one of these methods we compute two parameters: the mean power and the root mean square (RMS), in various frequency bands. The classification of the mental tasks was conducted with a linear discriminate analysis. The Welch periodogram and the Burg method performed better than the standard periodogram. The use of the RMS allows better classification accuracy than the obtained with the power of EEG signals.

JTD Keywords: Adult, Algorithms, Artificial Intelligence, Cognition, Electroencephalography, Female, Humans, Male, Pattern Recognition, Automated, Reproducibility of Results, Sensitivity and Specificity, Task Performance and Analysis, User-Computer Interface