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Talanta Jun 2024Tumor spheroids are widely studied for in vitro modeling of tumor growth and responses to anticancer drugs. However, current methods are mostly limited to static and...
Tumor spheroids are widely studied for in vitro modeling of tumor growth and responses to anticancer drugs. However, current methods are mostly limited to static and perfusion-based cultures, which can be improved by more accurately mimicking pathological conditions. Here, we developed a diffusion-based dynamic culture system for tumor spheroids studies using a thin membrane of hydrogel microwells and a microfluidic device. This allows for effective exchange of nutrients and metabolites between the tumors and the culture medium flowing underneath, resulting in uniform tumor spheroids. To monitor the growth and drug response of the spheroids in real-time, we performed spectroscopic analyses of the system's impedance, demonstrating a close correlation between the tumor size and the resistance and capacitance of the system. Our results also indicate an enhanced drug effect on the tumor spheroids in the presence of a low AC electric field, suggesting a weakening mechanism of the spheroids induced by external perturbation.
PubMed: 38950503
DOI: 10.1016/j.talanta.2024.126473 -
PloS One 2024The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life....
BACKGROUND
The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities.
OBJECTIVE
Our goal is to create a non-invasive preclinical imaging pipeline that can longitudinally probe murine placental health in vivo. We use advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development.
METHODOLOGY
We implement dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) and analysis pipeline to quantify uterine contraction and placental perfusion dynamics. We use optic flow and time-frequency analysis to quantify and characterize contraction-related placental motion. Our novel imaging and analysis pipeline uses subcutaneous administration of gadolinium for steepest slope-based perfusion evaluation, enabling non-invasive longitudinal monitoring.
RESULTS
We demonstrate that the placenta exhibits spatially asymmetric contractile motion that develops from E14.5 to E17.5. Additionally, we see that placental perfusion, perfusion delivery rate, and substrate delivery all increase from E14.5 to E17.5, with the High Perfusion Chamber (HPC) leading the placental changes that occur from E14.5 to E17.5.
DISCUSSION
We advance the placental perfusion chamber paradigm with a novel, physiologically based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and remodeling throughout gestation.
CONCLUSION
Our pipeline enables the non-invasive, longitudinal assessment of multiple placenta functions from a single imaging session. Our pipeline serves as a key toolbox for advancing research in mouse models of placental disease and disorder.
Topics: Animals; Female; Pregnancy; Magnetic Resonance Imaging; Mice; Placenta; Uterine Contraction; Contrast Media; Mice, Inbred C57BL
PubMed: 38950083
DOI: 10.1371/journal.pone.0303957 -
Minerva Cardiology and Angiology Jul 2024Heart failure (HF) is a clinical syndrome which is due to cardiac structural and/or functional abnormalities that result in elevated intra-cardiac pressures and/or...
Heart failure (HF) is a clinical syndrome which is due to cardiac structural and/or functional abnormalities that result in elevated intra-cardiac pressures and/or inadequate cardiac output. Hemodynamic assessment in HF allows the identification and characterization of cardiac dysfunction, systemic and/or pulmonary congestion and the eventual impairment of systemic perfusion which are fundamental to phenotype HF, risk stratify HF patients and to guide their treatment. Patient hemodynamics can be characterized invasively with right heart catheterization but also non-invasively with the use of echocardiography and other non-invasive ultrasound tools. The aim of the present review is to summarize the main echocardiographic and ultrasound parameters to characterize the hemodynamics of patients with HF and help clinicians to make the most of these non-invasive tools to guide HF patient management.
PubMed: 38949760
DOI: 10.23736/S2724-5683.24.06471-8 -
International Journal of Cancer Jul 2024Gliomas are primary brain tumors and are among the most malignant types. Adult-type diffuse gliomas can be classified based on their histological and molecular...
Gliomas are primary brain tumors and are among the most malignant types. Adult-type diffuse gliomas can be classified based on their histological and molecular signatures as IDH-wildtype glioblastoma, IDH-mutant astrocytoma, and IDH-mutant and 1p/19q-codeleted oligodendroglioma. Recent studies have shown that each subtype of glioma has its own specific distribution pattern. However, the mechanisms underlying the specific distributions of glioma subtypes are not entirely clear despite partial explanations such as cell origin. To investigate the impact of multi-scale brain attributes on glioma distribution, we constructed cumulative frequency maps for diffuse glioma subtypes based on T1w structural images and evaluated the spatial correlation between tumor frequency and diverse brain attributes, including postmortem gene expression, functional connectivity metrics, cerebral perfusion, glucose metabolism, and neurotransmitter signaling. Regression models were constructed to evaluate the contribution of these factors to the anatomic distribution of different glioma subtypes. Our findings revealed that the three different subtypes of gliomas had distinct distribution patterns, showing spatial preferences toward different brain environmental attributes. Glioblastomas were especially likely to occur in regions enriched with synapse-related pathways and diverse neurotransmitter receptors. Astrocytomas and oligodendrogliomas preferentially occurred in areas enriched with genes associated with neutrophil-mediated immune responses. The functional network characteristics and neurotransmitter distribution also contributed to oligodendroglioma distribution. Our results suggest that different brain transcriptomic, neurotransmitter, and connectomic attributes are the factors that determine the specific distributions of glioma subtypes. These findings highlight the importance of bridging diverse scales of biological organization when studying neurological dysfunction.
PubMed: 38949756
DOI: 10.1002/ijc.35068 -
Artificial Organs Jul 2024Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor...
BACKGROUND
Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor worldwide. The use of grafts based on extended donor criteria have become internationally accepted. Oxygenated machine perfusion technologies are the most recent advances in organ transplantation; however, it is only applied after a period of cold ischemia. Due to its high cost, we aimed to use a novel device, OxyFlush®, based on oxygenation of the preservation solution, applied during liver procurement targeting the maintenance of ATP during static cold storage (SCS).
METHODS
Twenty patients were randomly assigned to the OxyFlush or control group based on a 1:1 ratio. In the OxyFlush group, the perfusion solution was oxygenated with OxyFlush® device while the control group received a non-oxygenated solution. Liver and the common bile duct (CBD) biopsies were obtained at three different time points. The first was at the beginning of the procedure, the second during organ preparation, and the third after total liver reperfusion. Biopsies were analyzed, and adenosine triphosphate (ATP) levels and histological scores of the liver parenchyma and CBD were assessed. Postoperative laboratory tests were performed.
RESULTS
OxyFlush® was able to maintain ATP levels during SCS and improved the damage caused by the lack of oxygen in the CBD. However, OxyFlush® did not affect laboratory test results and histological findings of the parenchyma.
CONCLUSION
We present a novel low-cost device that is feasible and could represent a valuable tool in organ preservation during SCS.
PubMed: 38949484
DOI: 10.1111/aor.14815 -
Minerva Anestesiologica Jul 2024Brain dysfunction is a frequent complication of sepsis. Most likely, sepsis-associated brain dysfunction (SABD) results from the interaction between multiple factors:...
Brain dysfunction is a frequent complication of sepsis. Most likely, sepsis-associated brain dysfunction (SABD) results from the interaction between multiple factors: neurodegeneration due to microglial activation, altered neurotransmission, neuroinflammation and impairment of cerebral macro- and microcirculation. Altered brain perfusion might results from several mechanism: global or regional alterations in cerebral blood flow (CBF); reduced cerebral perfusion pressure - which is the driving force propelling blood through cerebral blood vessels - due to systemic hypotension; global or regional vasoconstriction; dysfunction of the intrinsic regulatory mechanisms of CBF, such as cerebral autoregulation and cerebrovascular reactivity; endothelial and blood-brain barrier dysfunction; autonomic nervous system dysfunction and metabolic uncoupling. Disorders of brain perfusion and CBF regulation are frequently observed in humans with sepsis, and intracranial hemodynamics monitoring can potentially be useful in clinical management of septic patients. The aim of this review is to provide an update of the current knowledge on alterations in brain hemodynamics associated with sepsis, along with physiological and methodological considerations intended to help the reader navigate the diverse results from published literature and a practical guide to apply non-invasive intracranial hemodynamics monitoring to septic patients in clinical practice.
PubMed: 38949458
DOI: 10.23736/S0375-9393.24.17978-3 -
Molecular Imaging and Radionuclide... Jun 2024To quantitatively evaluate the performance of the most used colormaps in image display using perceptual metrics and to what extent these measures are congruent with the...
OBJECTIVES
To quantitatively evaluate the performance of the most used colormaps in image display using perceptual metrics and to what extent these measures are congruent with the true intensity or uptake of pixels at different levels of defect severity in simulated cardiac images.
METHODS
Six colormaps, labeled "Gray", "Thermal", "Cool", "CEqual", "Siemens" and "S Pet" extracted from FIJI ImageJ software are included. Colormap data are converted from the red, green, blue color space to CIELAB. Perceptual metrics for measuring "color difference" were calculated, including difference (ΔE) and "speed". The pairwise color difference in every two levels or entries is visualized in a 2-dimensional "heatmap distance matrix" for each colormap. Curves are plotted for each colormap and compared. In addition, to apply this technique to clinical images, simulated short-axis cardiac slices with incremental defect severity (10% grading) were employed. The circumferential profile curves of true pixel intensity, lightness or luminance, and color difference are plotted simultaneously for each defect severity to visualize the concordance of the three curves in various colormaps.
RESULTS
In 0% defect, all the curves are at the highest level, except for "s pet", in that the lightness is not at its maximum value. In the phantom with 10% defect (or 90% of maximum value), discrepancies among curves appear. In "Siemens", the ΔE drops sharply. In "Siemens" colormap, the ΔE drops sharply. In 80% defect, ΔE curve, in "gray" colormap drops more slowly than other curves of other colormaps. In "s pet", lightness curve rises paradoxically, although the count intensity and ΔE curve match. In 70% defect, again, the curves are in good agreement in "thermal", "Siemens" and "cequal". However, a consistent lag exists in "gray". Up to 50% defect, curves maintain their expected pattern, but in defects more severe than 40%, lightness and ΔE curves in "cool" and "cequal" rise paradoxically, and in "thermal", they start to slow down in descent. In "Siemens", falling pattern of the three curves continues. For "s pet" colormap, an erratic pattern of lightness and ΔE curves exists.
CONCLUSION
Of 6 colormaps investigated for estimating defect severity, "grayscale" is less favorable than others and "thermal" performs slightly better. "S pet" or rainbow, which is used traditionally by many practitioners, is strongly discouraged. The "Siemens" colormap suffers from decreased discriminating power in the range of mild to moderate/severe. In contrast, the "cool" and "cequal" colormaps outperform the other colormaps employed in this study to some extent, although they have some shortcomings.
PubMed: 38949419
DOI: 10.4274/mirt.galenos.2024.34711 -
Journal of Visualized Experiments : JoVE Jun 2024Lung transplantation is hampered by the lack of suitable donors. Previously, donors that were thought to be marginal or inadequate were discarded. However, new and...
Lung transplantation is hampered by the lack of suitable donors. Previously, donors that were thought to be marginal or inadequate were discarded. However, new and exciting technology, such as ex vivo lung perfusion (EVLP), offers lung transplant providers extended assessment for marginal donor allografts. This dynamic assessment platform has led to an increase in lung transplantation and has allowed providers to use donors that were previously discarded, thus expanding the donor pool. Current perfusion techniques use cellular or acellular perfusates, and both have distinct advantages and disadvantages. Perfusion composition is critical to maintaining a homeostatic environment, providing adequate metabolic support, decreasing inflammation and cellular death, and ultimately improving organ function. Perfusion solutions must contain sufficient protein concentration to maintain appropriate oncotic pressure. However, current perfusion solutions often lead to fluid extravasation through the pulmonary endothelium, resulting in inadvertent pulmonary edema and damage. Thus, it is necessary to develop novel perfusion solutions that prevent excessive damage while maintaining proper cellular homeostasis. Here, we describe the application of a polymerized human hemoglobin (PolyhHb)-based oxygen carrier as a perfusate and the protocol in which this perfusion solution can be tested in a model of rat EVLP. The goal of this study is to provide the lung transplant community with key information in designing and developing novel perfusion solutions, as well as the proper protocols to test them in clinically relevant translational transplant models.
Topics: Animals; Rats; Lung Transplantation; Hemoglobins; Perfusion; Lung; Humans; Oxygen; Blood Substitutes; Male; Organ Preservation Solutions
PubMed: 38949382
DOI: 10.3791/66702 -
Journal of Visualized Experiments : JoVE Jun 2024Despite important advancements in the diagnosis and treatment of cardiovascular diseases (CVDs), the field is in urgent need of increased research and scientific...
Despite important advancements in the diagnosis and treatment of cardiovascular diseases (CVDs), the field is in urgent need of increased research and scientific advancement. As a result, innovation, improvement and/or repurposing of the available research toolset can provide improved testbeds for research advancement. Langendorff perfusion is an extremely valuable research technique for the field of CVD research that can be modified to accommodate a wide array of experimental needs. This tailoring can be achieved by personalizing a large number of perfusion parameters, including perfusion pressure, flow, perfusate, temperature, etc. This protocol demonstrates the versatility of Langendorff perfusion and the feasibility of achieving longer perfusion times (4 h) without graft function loss by utilizing lower perfusion pressures (30-35 mmHg). Achieving extended perfusion times without graft damage and/or function loss caused by the technique itself has the potential to eliminate confounding elements from experimental results. In effect, in scientific circumstances where longer perfusion times are relevant to the experimental needs (i.e., drug treatments, immunological response analysis, gene editing, graft preservation, etc.), lower perfusion pressures can be key for scientific success.
Topics: Animals; Perfusion; Rats; Heart Transplantation; Isolated Heart Preparation
PubMed: 38949317
DOI: 10.3791/66815 -
Journal of Visualized Experiments : JoVE Jun 2024Conventional static cold storage (SCS) exacerbates ischemic injury in the DCD liver, leading to severe complications for transplant recipients. To address this issue,...
Conventional static cold storage (SCS) exacerbates ischemic injury in the DCD liver, leading to severe complications for transplant recipients. To address this issue, clinical application of MP technology for donor liver preservation is underway. Simultaneously, efforts are focused on the development of various MP instruments, validated through relevant animal model experiments. Effective large animal trials play a pivotal role in clinical applications. However, challenges persist in the ex vivo preservation of DCD livers and the transplantation procedure in pigs. These hurdles encompass addressing the prolonged preservation of donor livers, conducting viability tests, alleviating ischemic injuries, and shortening the anhepatic phase. The use of a variable temperature-controlled MP device facilitates the prolonged preservation of DCD livers through sequential Dual Hypothermic Oxygenated Machine Perfusion (DHOPE) and Normothermic Machine Perfusion (NMP) modes. This protocol enhances the porcine OLTx model by improving the quality of DCD livers, optimizing the anastomosis technique, and reducing the duration of the anhepatic phase.
Topics: Animals; Liver Transplantation; Organ Preservation; Swine; Perfusion; Liver
PubMed: 38949305
DOI: 10.3791/65879