scholarly journals The effect of vascular diseases on bioimpedance measurements: mathematical modeling

2018 ◽  
Vol 5 (6) ◽  
Author(s):  
Yomna H. Shash ◽  
Mohamed A. A. Eldosoky ◽  
Mohamed T. Elwakad
Keyword(s):  
Mathematical Models ◽  
Vessel Wall ◽  
Vascular Diseases ◽  
Impedance Analysis ◽  
Wide Field ◽  
Vascular Disorders ◽  
Non Invasive ◽  
Novel Method ◽  
Inner Vessel ◽  
Arteries And Veins

Introduction: The non-invasive nature of bioimpedance technique is the reason for the adoption of this technique in the wide field of bio-research. This technique is useful in the analysis of a variety of diseases and has many advantages. Cardiovascular diseases are the most dangerous diseases leading to death in many regions of the world. Vascular diseases are disorders that affect the arteries and veins. Most often, vascular diseases have greater impacts on the blood flow, either by narrowing or blocking the vessel lumen or by weakening the vessel wall. The most common vascular diseases are atherosclerosis, wall swelling (aneurysm), and occlusion. Atherosclerosis is a disease caused by the deposition of plaques on the inner vessel wall, while a mural aneurysm is formed as a result of wall weakness. The main objective of this study was to investigate the effects of vascular diseases on vessel impedance. Furthermore, this study aimed to develop the measurement of vessel abnormalities as a novel method based on the bioimpedance phenomenon. Methods: Mathematical models were presented to describe the impedance of vessels in different vascular cases. In addition, a 3D model of blood vessels was simulated by COMSOL MULTIPHYSICS.5, and the impedance was measured at each vascular condition. Results: The simulation results clarify that the vascular disorders (stenosis, blockage or aneurysm) have significant impact on the vessel impedance, and thus they can be detected by using the bio-impedance analysis. Moreover, using frequencies in KHz range is preferred in detecting vascular diseases since it has the ability to differentiate between the healthy and diseased blood vessel. Finally, the results can be improved by selecting an appropriate electrodes configuration for analysis. Conclusion: From this work, it can be concluded that bioimpedance analysis (BIA) has the ability to detect vascular diseases. Furthermore, the proposed mathematical models are successful at describing different cases of vascular disorders.

The molecular mechanism of mechanotransduction in vascular homeostasis and disease

2020 ◽  
Vol 134 (17) ◽  
pp. 2399-2418
Author(s):  
Yoshito Yamashiro ◽  
Hiromi Yanagisawa
Keyword(s):  
Shear Stress ◽  
Blood Vessels ◽  
Vessel Wall ◽  
Vascular Diseases ◽  
Cell Interactions ◽  
Aortic Aneurysms ◽  
Cyclic Stretch ◽  
Mechanical Stimuli ◽  
Vascular Homeostasis ◽  
Matrix Cell

Abstract Blood vessels are constantly exposed to mechanical stimuli such as shear stress due to flow and pulsatile stretch. The extracellular matrix maintains the structural integrity of the vessel wall and coordinates with a dynamic mechanical environment to provide cues to initiate intracellular signaling pathway(s), thereby changing cellular behaviors and functions. However, the precise role of matrix–cell interactions involved in mechanotransduction during vascular homeostasis and disease development remains to be fully determined. In this review, we introduce hemodynamics forces in blood vessels and the initial sensors of mechanical stimuli, including cell–cell junctional molecules, G-protein-coupled receptors (GPCRs), multiple ion channels, and a variety of small GTPases. We then highlight the molecular mechanotransduction events in the vessel wall triggered by laminar shear stress (LSS) and disturbed shear stress (DSS) on vascular endothelial cells (ECs), and cyclic stretch in ECs and vascular smooth muscle cells (SMCs)—both of which activate several key transcription factors. Finally, we provide a recent overview of matrix–cell interactions and mechanotransduction centered on fibronectin in ECs and thrombospondin-1 in SMCs. The results of this review suggest that abnormal mechanical cues or altered responses to mechanical stimuli in EC and SMCs serve as the molecular basis of vascular diseases such as atherosclerosis, hypertension and aortic aneurysms. Collecting evidence and advancing knowledge on the mechanotransduction in the vessel wall can lead to a new direction of therapeutic interventions for vascular diseases.

Current uses of intracranial vessel wall imaging for clinical practice: a high-resolution MR technique recently available

2020 ◽  
Vol 78 (10) ◽  
pp. 642-650
Author(s):  
Felipe Torres PACHECO ◽  
Luiz Celso Hygino da CRUZ JUNIOR ◽  
Igor Gomes PADILHA ◽  
Renato Hoffmann NUNES ◽  
Antônio Carlos Martins MAIA JUNIOR ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Vessel Wall ◽  
Vascular Diseases ◽  
Vascular Wall ◽  
Vessel Wall Imaging ◽  
Clinical Settings ◽  
Direct Evaluation ◽  
Intracranial Vessel ◽  
Indirect Evaluation ◽  
Wall Imaging

ABSTRACT Intracranial vessel wall imaging plays an increasing role in diagnosing intracranial vascular diseases. With the growing demand and subsequent increased use of this technique in clinical practice, radiologists and neurologists should be aware of the choices in imaging parameters and how they affect image quality, clinical indications, methods of assessment, and limitations in the interpretation of these images. Due to the improvement of the MRI techniques, the possibility of accurate and direct evaluation of the abnormalities in the arterial vascular wall (vessel wall imaging) has evolved, adding substantial data to diagnosis when compared to the indirect evaluation based on conventional flow analyses. Herein, the authors proposed a comprehensive approach of this technique reinforcing appropriated clinical settings to better use intracranial vessel wall imaging.

Bee Markers: A Novel Method for Non-Invasive Short Term Marking of Bats

2020 ◽  
Vol 21 (2) ◽  
pp. 465 ◽  
Author(s):  
Lucinda Kirkpatrick ◽  
Grzegorz Apoznański ◽  
Luc De Bruyn ◽  
Ralf Gyselings ◽  
Tomasz Kokurewicz
Keyword(s):  
Short Term ◽  
Non Invasive ◽  
Novel Method

Endothelial Dysfunction and Inflammatory Markers of Vascular Disease

2020 ◽  
Vol 19 (3) ◽  
pp. 243-249 ◽  
Author(s):  
Sevket Balta
Keyword(s):  
Endothelial Dysfunction ◽  
Vascular Disease ◽  
Inflammatory Markers ◽  
Vascular Diseases ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Non Invasive ◽  
Von Willebrand ◽  
The Relationship ◽  
Willebrand Factor

: Vascular diseases are the main reason for morbidity and mortality worldwide. As we know, the earlier phase of vascular diseases is endothelial dysfunction in humans, the endothelial tissues play an important role in inflammation, coagulation, and angiogenesis, via organizing ligand-receptor associations and the various mediators’ secretion. We can use many inflammatory non-invasive tests (flowmediated dilatation, epicedial fat thickness, carotid-intima media thickness, arterial stiffness and anklebrachial index) for assessing the endothelial function. In addition, many biomarkers (ischemia modified albumin, pentraxin-3, E-selectin, angiopoietin, endothelial cell specific molecule 1, asymmetrical dimethylarginine, von Willebrand factor, endothelial microparticles and endothelial progenitor cells) can be used to evaluate endothelial dysfunction. We have focused on the relationship between endothelial dysfunction and inflammatory markers of vascular disease in this review.

scholarly journals Effect of position and exercise on measurement of muscle quantity and quality: towards a standardised pragmatic protocol for clinical practice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Carly Welch ◽  
Zeinab Majid ◽  
Isabelle Andrews ◽  
Zaki Hassan-Smith ◽  
Vicky Kamwa ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Skeletal Muscle Mass ◽  
Rectus Femoris ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Upper Body ◽  
Fat Percentage ◽  
Non Invasive ◽  
Vastus Intermedius ◽  
Total Body

Abstract Background Ultrasonography is an emerging non-invasive bedside tool for muscle quantity/quality assessment; Bioelectrical Impedance Analysis (BIA) is an alternative non-invasive bedside measure of body composition, recommended for evaluation of sarcopenia in clinical practice. We set out to assess impact of position and exercise upon measures towards protocol standardisation. Methods Healthy volunteers aged 18–35 were recruited. Bilateral Anterior Thigh Thickness (BATT; rectus femoris and vastus intermedius), BATT: Subcutaneous Ratio (BATT:SCR), and rectus femoris echogenicity were measured using ultrasound and BIA was performed; 1) lying with upper body at 45° (Reclined), 2) lying fully supine at 180o (Supine), 3) sat in a chair with upper body at 90o (Sitting), and 4) after exercise Reclined. Variability of Skeletal Muscle Mass (SMM) by two different equations from BIA (SMM-Janssen, SMM-Sergi), phase angle, fat percentage, and total body (TBW), extracellular (ECW), and intracellular water (ICW) were assessed. Results Forty-four participants (52% female; mean 25.7 years-old (SD 5.0)) were recruited. BATT increased from Reclined to Sitting (+ 1.45 cm, 1.27–1.63), and after exercise (+ 0.51, 0.29–0.73). Echogenicity reduced from Reclined to Sitting (− 2.1, − 3.9 – -0.26). SMM-Sergi declined from Reclined to Supine (− 0.65 kg, − 1.08 – − 0.23) and after exercise (− 0.70 kg, − 1.27 – -0.14). ECW increased from Reclined to Sitting (+ 1.19 L, 0.04–2.35). There were no other statistically significant changes. Conclusion Standardisation of protocols is especially important for assessment of muscle quantity by ultrasonography; BIA measurements may also vary dependent on the equations used. Where possible, participants should be rested prior to muscle ultrasonography and BIA, and flexion of the knees should be avoided.

scholarly journals Multiplexed Non-invasive in vivo Imaging to Assess Metabolism and Receptor Engagement in Tumor Xenografts

2019 ◽  
Author(s):  
Alena Rudkouskaya ◽  
Nattawut Sinsuebphon ◽  
Marien Ochoa ◽  
Joe E. Mazurkiewicz ◽  
Xavier Intes ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Targeted Delivery ◽  
Near Infrared ◽  
Metabolic Response ◽  
Imaging Modalities ◽  
Wide Field ◽  
Receptor Ligand ◽  
Non Invasive ◽  
Intracellular Drug Delivery

AbstractFollowing an ever-increased focus on personalized medicine, there is a continuing need to develop preclinical molecular imaging modalities to guide the development and optimization of targeted therapies. To date, non-invasive quantitative imaging modalities that can comprehensively assess simultaneous cellular drug delivery efficacy and therapeutic response are lacking. In this regard, Near-Infrared (NIR) Macroscopic Fluorescence Lifetime Förster Resonance Energy Transfer (MFLI-FRET) imaging offers a unique method to robustly quantify receptor-ligand engagement in vivo and subsequent intracellular internalization, which is critical to assess the delivery efficacy of targeted therapeutics. However, implementation of multiplexing optical imaging with FRET in vivo is challenging to achieve due to spectral crowding and cross-contamination. Herein, we report on a strategy that relies on a dark quencher that enables simultaneous assessment of receptor-ligand engagement and tumor metabolism in intact live mice. First, we establish that IRDye QC-1 (QC-1) is an effective NIR dark acceptor for the FRET-induced quenching of donor Alexa Fluor 700 (AF700) using in vitro NIR FLI microscopy and in vivo wide-field MFLI imaging. Second, we report on simultaneous in vivo imaging of the metabolic probe IRDye 800CW 2-deoxyglucose (2-DG) and MFLI-FRET imaging of NIR-labeled transferrin FRET pair (Tf-AF700/Tf-QC-1) uptake in tumors. Such multiplexed imaging revealed an inverse relationship between 2-DG uptake and Tf intracellular delivery, suggesting that 2-DG signal may predict the efficacy of intracellular targeted delivery. Overall, our methodology enables for the first time simultaneous non-invasive monitoring of intracellular drug delivery and metabolic response in preclinical studies.

scholarly journals Separation of cortical arteries and veins in optical neurovascular imaging

2014 ◽  
Vol 07 (03) ◽  
pp. 1350069 ◽  
Author(s):  
Linna Zhao ◽  
Yao Li ◽  
Hongyang Lu ◽  
Lu Yuan ◽  
Shanbao Tong
Keyword(s):  
Cerebral Cortex ◽  
Optical Imaging ◽  
Signal To Noise Ratio ◽  
Vascular Diseases ◽  
Region Growing ◽  
Field Method ◽  
Laser Speckle ◽  
Cerebral Vessel ◽  
Full Field ◽  
Arteries And Veins

Separation of arteries and veins in the cerebral cortex is of significant importance in the studies of cortical hemodynamics, such as the changes of cerebral blood flow, perfusion or oxygen concentration in arteries and veins under different pathological and physiological conditions. Yet the cerebral vessel segmentation and vessel-type separation are challenging due to the complexity of cortical vessel characteristics and low spatial signal-to-noise ratio. In this work, we presented an effective full-field method to differentiate arteries and veins in cerebral cortex using dual-modal optical imaging technology including laser speckle imaging (LSI) and optical intrinsic signals (OIS) imaging. The raw contrast images were acquired by LSI and processed with enhanced laser speckle contrast analysis (eLASCA) algorithm. The vascular pattern was extracted and segmented using region growing algorithm from the eLASCA-based LSI. Meanwhile, OIS images were acquired alternatively with 630 and 870 nm to obtain an oxyhemoglobin concentration map over cerebral cortex. Then the separation of arteries and veins was accomplished by Otsu threshold segmentation algorithm based on the OIS information and segmentation of LSI. Finally, the segmentation and separation performances were assessed using area overlap measure (AOM). The segmentation and separation of cerebral vessels in cortical optical imaging have great potential applications in full-field cerebral hemodynamics monitoring and pathological study of cerebral vascular diseases, as well as in clinical intraoperative monitoring.

Abstract 512: Collagen Homologous Sequence R1R2 Mediates Vascular Remodeling by Decreasing Inflammation and Smooth Muscle Proliferation

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Ting-Hein Lee ◽  
Hou-Yu Chiang
Keyword(s):  
Smooth Muscle ◽  
Vascular Disease ◽  
Vascular Remodeling ◽  
Vessel Wall ◽  
Inflammatory Cell ◽  
Vascular Diseases ◽  
Inflammatory Cell Infiltration ◽  
Collagen I ◽  
Cell Infiltration ◽  
Ecm Proteins

The extracellular matrix (ECM) is a major constituent of the vessel wall. Except for providing a structural scaffold for cells, ECM controls numerous cellular functions like adhesion, growth, migration and differentiation. The components of ECM are mediated by the interplay between ECM synthesis, deposition, degradation and the interaction between ECM proteins. Vascular remodeling occurs in the vascular diseases and is characterized by endothelial cell activation, inflammatory cell infiltration, smooth muscle cell (SMC) proliferation/migration, and augmented deposition of ECM proteins. Collagen I is the major ECM component in the arterial wall, excess collagen I accumulation may exacerbate the vascular disease by further facilitating SMC proliferation/migration. Therefore, treatments to inhibit excess collagen deposition could provide a remedy for vascular disease. R1R2, a peptide derived from the bacterial adhesin SFS with sequence homology to collagen, is known to inhibit collagen I deposition by inhibiting the binding of fibronectin to collagen. Studies have revealed that R1R2 affects collagen I-dependent cell growth and migration in vitro. However, the in vivo functions of R1R2 during vascular remodeling remain unknown. We hypothesized that R1R2 prevents excess collagen I accumulation and SMC proliferation, resulting in decreased neointimal formation. We induced vascular remodeling by ligating the carotid artery on mice. Delivery of R1R2 was periadventially applied using pluronic gel and evaluated its effects on vascular remodeling, ECM deposition, SMC proliferation and differentiation. Morphometric analysis demonstrated that R1R2 reduced intima-media thickening by 50% compared to the control group. R1R2 treatment also decreased collagen I deposition in the vessel wall and maintained SMC in the contractile phenotype. Interestingly, R1R2 dramatically reduced inflammatory cell infiltration into the vessel by 80% accompanied with decreased VCAM-1 and ICAM-1. In conclusion, our data showed that R1R2 attenuates the vascular remodeling response by decreasing inflammation and SMC proliferation/migration. These studies provide a therapeutic potential of periadventitially delivering R1R2 in treating vascular diseases.

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