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Wearable Sensors for Blood Perfusion Monitoring in Patients with Diabetes Mellitus
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Evgenii A. Zherebtsov, Elena V. Zharkikh, Yulia I. Loktionova, Angelina I. Zherebtsova, Viktor V. Sidorov, Alexander I. Krupatkin, Andrey V. Dunaev
At the level of non-muscle metabolic microvessels (capillaries), the main objects for microcirculation regulation are the exchange surface area determined by the number of perfused capillaries and the exchange processes (mass transfer of water- and fat-soluble substances) occurred in the capillary wall.
Recent in vitro Models for the Blood-Brain Barrier
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
João Basso, Maria Mendes, Maria Ferreira, João Sousa, Alberto Pais, Carla Vitorino
Using different production strategies and materials, the scaffolds of the microvessels are first created and the endothelial cells are subsequently seeded to form the microvessels themselves. This is the basis of the formation of the microvessels in parallel and 3D tubular structure designs. In vasculogenesis designs, there are no previously formed scaffolds. Instead, endothelial cells are seeded next to a collagen matrix or fibrin hydrogel and allowed to sprout and form de novo microvessels [29, 30]. These more natural structures may better reproduce the interactions between the cells of the neurovascular units. Nevertheless, these models are more irregular and possess a higher variability and lower experimental reproducibility [21].
Disorders in tHemostasis System and Changes in the Rheological Properties of the Blood in Ischemic Heart Disease and Diabetes Mellitus Patients
Published in E.I. Sokolov, Obesity and Diabetes Mellitus, 2020
The flow of blood in a microcirculation channel is affected the most by rheological factors. Since the size of the microvessels is compatible with the diameter of an erythrocyte, of significance are also the mechanical properties of individual cells, primarily the deformability of the erythrocytes. Its lowering is important for the blood flow in microvessels. The rigid cells that cannot enter a capillary rapidly cause the formation of cell clusters in the vessels (stasis), emptying of the capillaries, and, in the long run, the formation of regions with local hypoxia [24, 53, 81, 181, 440, 504, 540].
Novel transdermal curcumin therapeutic preserves endothelial barrier function in a high-dose LPS rat model
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
William H. Nugent, Danuel A. Carr, Joel Friedman, Bjorn K. Song
Sepsis—a driver of systemic inflammatory response syndrome—accounts for 20% of global deaths annually [1]. Despite a complex and multifaceted pathology triggered and perpetuated by widespread innate immune activity, the true “motor of sepsis” is recognised as microvascular dysfunction [2], which stems from endothelial barrier breakdown [3]. While inflammation is a necessary component of homeostatic restoration following infection and injury, the process disrupts normal vascular function [4,5]. Microvessels dilate and their endothelial linings—the endothelial surface layer (ESL/glycocalyx) in contact with the blood—become porous permitting the extravasation of fluids, solutes, neutrophils, and macrophages. Locally, so-called “leaky vessels” have a minor impact on circulatory volume, but can lead to circulatory failure when dysregulated at a systemic level. The damaged endothelium also becomes prothrombotic, increasing red blood cell aggregation to create pockets of microvascular ischaemia [6]. Coupled with hypovolemia, capillary beds become ischaemic causing organ damage, which is proximate to severe morbidity and mortality in sepsis [7].
Extravasation of biodegradable microspheres in the rat brain
Published in Drug Delivery, 2023
Anne-Eva van der Wijk, Theodosia Georgakopoulou, Rob Steendam, Johan Zuidema, Peter L. Hordijk, Erik N.T.P. Bakker, Ed van Bavel
Images of 100 µm-thick brain sections were captured using a confocal laser scanning microscope SP8-X DLS Lightsheet (Leica Microsystems, Wetzlar, Germany) with a 10 × 0.5 NA (air) objective for Iba1, NeuN and IgG, or SP8-X (Leica Microsystems) with a 20 × 0.75 NA (oil) objective for laminin. We used relatively thick session for confocal imaging in order to better image the spatial relation between the microvessels and the 13 micron microspheres, needed for determining the extravasation state, and to include the (oblique) vessels over a sufficient length to allow assessment of perfusion state. In order to cover the full thickness, z-stacks were constructed of 5 micron optical slice thickness and a maximum intensity projection was made over the 100 micron. Signal intensity decreased in deeper layers but was strong enough to allow a sufficient signal to noise ratio and visualization. For the imaging and quantification of IgG leakage and Iba1 signal intensity, we used a single 5 micron plane close to the surface, tiled over both hemispheres.
Recent advances in drug delivery systems for targeting brain tumors
Published in Drug Delivery, 2023
Yi Zhao, Ping Yue, Yao Peng, Yuanyuan Sun, Xing Chen, Ze Zhao, Bingjie Han
The tumor microenvironment includes tumor cells, tumor stem cells, blood vessels, lymphatic, immune cells, fibroblasts, and extracellular matrix, which provides a suitable environment for the growth, division, angiogenesis and metastasis of tumor cells (Petrova et al., 2018). And TME protects tumor cells mainly through the following mechanisms. The increased activity of vascular endothelial growth factor leads to the high proliferation of microvessels. Tumor cells interact with secreted cytokines or growth factors to obtain nutrients from abnormal blood vessels, which in turn induce fibroblasts and macrophages to proliferate and invade, resulting in drug resistance. The cross-linking structure of extracellular matrix formed by the fibrous collagen, proteoglycan, stromal cell protein and hyaluronic acid prevents drugs from reaching tumor cells through the microenvironment, thus resisting the drugs treatment. In addition to providing integral structure, extracellular matrix also contributes to the transport of nutrients and oxygen, thereby promoting tumor initiation and progression.