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Microvascular Research

Stephen C Kanick, Peter A Schneider, Bruce Klitzman, Natalie A Wisniewski, Kerstin Rebrin
Measurements of regional tissue oxygen serve as a proxy to monitor local perfusion and have the potential to guide therapeutic decisions in multiple clinical disciplines. Transcutaneous oximetry (tcpO2 ) is a commercially available noninvasive technique that uses an electrode to warm underlying skin tissue and measure the resulting oxygen tension at the skin surface. A novel approach is to directly measure interstitial tissue oxygen using subcutaneous oxygen microsensors composed of a biocompatible hydrogel carrier platform with embedded oxygen sensing molecules...
February 8, 2019: Microvascular Research
Josefine Bunke, Rafi Sheikh, Nina Reistad, Malin Malmsjö
BACKGROUND: The aim of this study was to investigate the possibility of using extended-wavelength diffuse reflectance spectroscopy (EW-DRS) to measure tissue response related to blood perfusion. The study was performed on a model that we have previously found to be useful for studying techniques for perfusion monitoring following the injection of epinephrine in a local anesthetic in the human forearm. METHODS: Nine healthy subjects were included in the study. Spectroscopy was performed with an EW-DRS system using a combination of two spectrometers to resolve light in the visible (350 nm to 1100 nm) and the near-infrared regions (900 nm to 1700 nm)...
February 2, 2019: Microvascular Research
Farshad M Kashkooli, M Soltani, M Rezaeian, Erfan Taatizadeh, Mohammad-Hossein Hamedi
The solute transport distribution in a tumor is an important criterion in the evaluation of the cancer treatment efficacy. The fraction of killed cells after each treatment can quantify the therapeutic effect and plays as a helpful tool to evaluate the chemotherapy treatment schedules. In the present study, an image-based spatio-temporal computational model of a solid tumor is provided for calculation of interstitial fluid flow and solute transport. Current model incorporates heterogeneous microvasculature for angiogenesis instead of synthetic mathematical modeling...
January 31, 2019: Microvascular Research
Karalyn E McRae, Jessica Pudwell, Nichole Peterson, Graeme N Smith
Preeclampsia (PE) is characterized by systemic maternal endothelial dysfunction. Changes in endothelial reactivity have been reported before the onset of clinical signs of PE, and continuing into the post-partum period. Women who smoke during pregnancy have a 33% reduced risk of developing PE. This reduced risk is hypothesized to be, in part, attributed to carbon monoxide (CO), a by-product of cigarette combustion and a known endogenous vasodilator. Determining the vascular effects of CO in healthy women, may inform how CO can improve endothelial function and have promise as a novel therapeutic for PE...
January 15, 2019: Microvascular Research
Ashish Tiwari, Satyendra Singh Chauhan
Present work concerns the pulsatile blood flow of two-fluid model through porous blood vessels under the effect of radially varying viscosity. Blood is modeled as two-phase fluid model consisting a core region by non-Newtonian (Herschel-Bulkley) fluid and a plasma region modeled as Newtonian fluid. No slip condition has been used on wall and pressure gradient is taken as periodic function of time. Up to first order approximate solutions of governing equations are obtained using perturbation approach. A comparative analysis for relative change in flow resistance between our model and previously studied single and two-fluid models without porous layer near wall has also been done...
January 11, 2019: Microvascular Research
Kaiming Liu, Liang Guo, Zhijian Zhou, Mengxiong Pan, Chuanzhu Yan
Mesenchymal stem cells can be used as a novel treatment of ischemic stroke, but their therapeutic effect and mechanism of action require further evaluation. Mitochondrial dysfunction has core functions in ischemia-reperfusion stroke injury. Our recent research has demonstrated that mesenchymal stem cells can transfer their functional mitochondria to injured endothelial cells via tunneling nanotubes in vitro, resulting in the rescue of aerobic respiration and protection of endothelial cells from apoptosis. Therefore, we presume that the mechanisms of mitochondrial protection may be involved in stem cell-mediated rescue of injured cerebral microvasculature and recovery from ischemic stroke...
January 3, 2019: Microvascular Research
Magdalena Hoffmann, Jolanta Neubauer-Geryk, Melanie Wielicka, Magdalena Kowaleczko, Małgorzata Myśliwiec, Leszek Bieniaszewski
BACKGROUND: The impairment of endothelial function in type 1 diabetes mellitus (DM1) is considered as the basis of microvascular complications. In DM1 patients autoimmune thyroiditis is a frequent comorbidity which may be responsible for further deterioration of microcirculation function. In studies investigating the relationship between cardiovascular risk factors and microvascular function, skin microcirculation is widely used. The aim of our study was to evaluate the impact of coexisting autoimmune thyroiditis on skin microcirculation in children with type I diabetes mellitus...
January 3, 2019: Microvascular Research
Jiping Yang
Oxidative stress, which is defined as an imbalance between proxidant and antioxidant systems, is the essential mechanism involving in the ischemic process. During the early stage of brain ischemia, reactive oxygen species (ROS) are increased. Increased ROS are thought of a consequence of brain ischemia and exacerbating disease due to inducing cell death, apoptosis and senescence by oxidative stress. During brain tissue repair, ROS are act as signaling molecules and may be benefical for regulating angiogenesis and preventing tissue injury...
December 27, 2018: Microvascular Research
R W Flower, Z Mirza, S R Thom
Fluorescence-mediated photoplethysmography (FM-PPG) is the first routine clinical methodology by which to quantifiably measure tissue blood perfusion in absolute terms (mL blood/sec ∗ mm2 tissue). The FM-PPG methodology has been described in detail previously in this journal (MVR 114, 2017, 92-100), along with initial proof-of-concept measurements of blood perfusion in both ocular and forearm skin tissues. The motivation for the current study was to investigate whether FM-PPG can be used readily and routinely under realistic clinical conditions...
December 24, 2018: Microvascular Research
Tao Wang, Haobo Su, Wensheng Lou, Jianping Gu, Xu He, Liang Chen, Guoping Chen, Jinhua Song, Wanyin Shi, Chishing Zee, Bihong T Chen
OBJECTIVE: To evaluate perfusion alterations in skeletal muscle in a canine hind limb ischemia model using color-coded digital subtraction angiography (CC-DSA). METHODS: Twelve beagles underwent embolization at the branch of their left deep femoral artery. Right hind limbs were used as the control group. Angiography was performed before and immediately after embolization. Upon CC-DSA analysis, time to peak (TTP) was measured before embolization in both sides of the beagles' hind limbs at the middle iliac artery, and the distant, middle and proximal femoral artery...
December 18, 2018: Microvascular Research
Joseph C Giacalone, Matthew J Miller, Grefachew Workalemahu, Austin J Reutzel, Dalyz Ochoa, S Scott Whitmore, Edwin M Stone, Budd A Tucker, Robert F Mullins
Age-related macular degeneration (AMD) is a common cause of blindness worldwide. While recent studies have revealed that the loss of choroidal endothelial cells (ChECs) is critical to the disease pathogenesis of dry AMD, in vitro studies are needed to fully elucidate the disease mechanism. However, these studies remain hindered due to the lack of publically available human ChEC lines. To address this need, ChECs were harvested form donor tissue and enriched for by using magnetic cell separation using anti-CD31 conjugated microbeads...
December 17, 2018: Microvascular Research
Mariana Pereira Goldim, Lucineia Gainski Danielski, Judite Filgueiras Rodrigues, Larissa Joaquim, Leandro Garbossa, Aloir Neri de Oliveira Junior, Kiuanne Lino Lobo Metzker, Amanda Della Giustina, Taise Cardoso, Tatiana Barichello, Fabricia Petronilho
BACKGROUND: The choroid plexus (CP), main component of blood-cerebrospinal fluid barrier (BCSFB), protects the brain from peripheral inflammation similar to the blood-brain barrier. Thus, CP is considered a critical target site of oxidative damage, which in sepsis oxidative stress is likely to be a major step in the development of brain damage. Functional alterations in CP may be associated with sepsis-induced brain injury. However, there is no description on the mechanisms associated with BCSFB disruption during sepsis development...
December 12, 2018: Microvascular Research
V K Narla, Dharmendra Tripathi
The flow through curved microvessels has more realistic applications in physiological transport phenomena especially in blood flow through capillary and microvessels. Motivated by the biomicrofluidics applications, a mathematical model is developed to describe the blood flow inside a curved microvessel driven by electroosmosis. In addition to this flow, the channel experiences electric double layer phenomenon due to zeta potential about -25mV. Lubrication theory and Debye-Hückel approximation are employed to obtain analytical solution for electric potential function...
December 10, 2018: Microvascular Research
Guifang Sun, Fengqi Liu, Chunhong Xiu
INTRODUCTION: Coronary microcirculation disturbance plays an important role in chronic heart failure (CHF). High thoracic sympathetic block (HTSB) is effective to treat CHF, but its impact on coronary microcirculation is unclear. METHODS: Forty male Wistar rats were subcutaneously injected with isoproterenol (340 mg/kg) for 2 days. Eight weeks later, 24 surviving rats were randomized to the CHF and HTSB groups and 10 rats were used as the control group. 50 μl of saline and ropivacaine (0...
December 1, 2018: Microvascular Research
Sarah Skinner, Philippe Connes, Dominique Sigaudo-Roussel, Ming Lo, Kiao Ling Liu, Elie Nader, Audrey Josset-Lamaugarny, Emmanuelle Charrin, Cyril Martin, Camille Romanet-Faes, Mor Diaw, Vincent Pialoux, Bérengère Fromy
OBJECTIVE: Type 2 diabetes (T2D)-related vascular dysfunction and hemorheological abnormalities could possibly be amplified by sickle cell trait (SCT). These alterations could potentially increase the risk of vascular complications in individuals with combined T2D and SCT. Therefore, this study used a mouse model to determine whether vascular function and blood rheology were more severely altered in combined T2D and SCT than in T2D or SCT alone. METHODS: Townes transgenic mice with or without SCT received a 12-week high fat high sucrose or standard diet to create models of combined T2D-SCT, T2D, SCT, and controls...
December 1, 2018: Microvascular Research
Sherry G Clendenon, Xiao Fu, Robert A Von Hoene, Jeffrey L Clendenon, James P Sluka, Seth Winfree, Henry Mang, Michelle Martinez, Adele J Filson, James E Klaunig, James A Glazier, Kenneth W Dunn
Microvascular perfusion dynamics are vital to physiological function and are frequently dysregulated in injury and disease. Typically studies measure microvascular flow in a few selected vascular segments over limited time, failing to capture spatial and temporal variability. To quantify microvascular flow in a more complete and unbiased way we developed STAFF (Spatial Temporal Analysis of Fieldwise Flow), a macro for FIJI open-source image analysis software. Using high-speed microvascular flow movies, STAFF generates kymographs for every time interval for every vascular segment, calculates flow velocities from red blood cell shadow angles, and outputs the data as color-coded velocity map movies and spreadsheets...
November 28, 2018: Microvascular Research
Leila Hadjadj, Anna Monori-Kiss, Eszter M Horváth, Andrea Heinzlmann, Attila Magyar, Réka E Sziva, Zsuzsanna Miklós, Éva Pál, János Gál, István Szabó, Zoltán Benyó, György L Nádasy, Szabolcs Várbíró
Vitamin D (VitD) hypovitaminosis and androgen excess (AE) are both risk factors for cardiovascular diseases in fertile women. However, the possible early interaction between AE and VitD status is not clear. Our goal was to describe how VitD status influences early changes in the biomechanical reactivity of small coronary arterioles in adult female rats after transdermal testosterone treatment. Forty-six adolescent, 90-110-gram-weighed female Wistar rats were randomly grouped into 4 groups. Twenty-four animals received an optimal VitD-supplemented diet, from which 12 animals underwent transdermal testosterone treatment...
November 28, 2018: Microvascular Research
Gamze Aslan, Veli Polat, Evin Bozcali, Selçuk Opan, Nurcan Çetin, Dilek Ural
OBJECTIVES: Coronary microvascular dysfunction plays a major role in the pathogenesis of microvascular angina (MVA). Along with endothelial dysfunction, microvascular atherosclerosis and inflammation seem to contribute to the development of coronary microvascular dysfunction. Serum soluble ST2 (sST2) and serum soluble CD40 ligand (sCD40L) are two biomarkers associated with inflammation and atherosclerosis. The aim of this study was to investigate the role of these biomarkers in the pathogenesis of MVA and determine their possible association with coronary microvascular dysfunction...
November 28, 2018: Microvascular Research
Ali Javinani, Mehran Pournazari, Ahmad Reza Jamshidi, Hoda Kavosi
INTRODUCTION: Takayasu arteritis (TA) is a large vessel vasculitis characterized by the involvement of the aorta and its branches. In the present study, the nailfold videocapillaroscopy (NVC) findings of the TA patients were evaluated and compared to healthy individuals. Additionally, the association of NVC abnormalities with disease activity and subclavian artery involvement was also investigated. METHOD: In the present study, NVC changes of 15 TA patients and 15 age- and sex-matched healthy controls were compared...
March 2019: Microvascular Research
Robert L Conhaim, Gilad S Segal, Kal E Watson
Pulmonary alveolar septal capillaries receive their perfusion from a web of larger surrounding acinar vessels. Using 4 μm diam. Latex particles, we showed that positive pressure ventilation narrowed the acinar vessels as evidenced by venous 4 μm particle concentrations and perfusate flows <50% of particle concentrations in negative pressure ventilated lungs. We aimed to understand the effects of positive and negative pressure ventilation on flows of larger particles through the lung. Isolated, ventilated rat lungs (air, transpulmonary pressures of 15/5 cm H2O, 25 breaths/min) were perfused with a hetastarch solution at Ppulm art/PLA pressures of 10/0 cm H2O...
November 24, 2018: Microvascular Research
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