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Microvascular disease

M A Zouache, I Eames, C A Klettner, P J Luthert
The development of fluid transport systems was a key event in the evolution of animals and plants. While within vertebrates branched geometries predominate, the choriocapillaris, which is the microvascular bed that is responsible for the maintenance of the outer retina, has evolved a planar topology. Here we examine the flow and mass transfer properties associated with this unusual geometry. We show that as a result of the form of the choriocapillaris, the blood flow is decomposed into a tessellation of functional vascular segments of various shapes delineated by separation surfaces across which there is no flow, and in the vicinity of which the transport of passive substances is diffusion-limited...
October 25, 2016: Scientific Reports
Christina Cimenti, Axel Schlagenhauf, Bettina Leschnik, Elke Fröhlich-Reiterer, Hildegard Jasser-Nitsche, Harald Haidl, Elisabeth Suppan, Gudrun Weinhandl, Maximilian Leberl, Martin Borkenstein, Wolfgang E Muntean
BACKGROUND: Micro- and macrovascular diseases are frequent complications in patients with diabetes. Hypercoagulability may contribute to microvascular alterations. OBJECTIVE: In this study, we investigated whether type 1 diabetes in children is associated with a hypercoagulable state by performing a global function test of coagulation - the thrombin generation assay. SUBJECTS: 75 patients with type 1 diabetes aged between 2 and 19years were compared to an age-matched healthy control group...
October 17, 2016: Thrombosis Research
Alejandro R Chade, John E Hall
Obesity is largely responsible for the growing incidence and prevalence of diabetes, cardiovascular and renal diseases. Current strategies to prevent and treat obesity and its consequences have been insufficient to reverse the ongoing trends. Lifestyle modification or pharmacological therapies often produce modest weight loss which is not sustained and recurrence of obesity is frequently observed, leading to progression of target organ damage in many obese subjects. Therefore, research efforts have focused not only on the factors that regulate energy balance, but also on understanding mechanisms of target organ injury in obesity...
October 22, 2016: American Journal of Nephrology
Hulya Yalçin, Ines Valenta, Fatih Yalçin, Celia Corona-Villalobos, Nestor Vasquez, Joshua Ra, Nagehan Kucukler, Abdel Tahari, Iraklis Pozios, Yun Zhou, Martin Pomper, Theodore P Abraham, Thomas H Schindler, M Roselle Abraham
Vasodilator-induced transient left ventricular (LV) cavity dilation by positron emission tomography (PET) is common in patients with hypertrophic cardiomyopathy (HC). Because most patients with PET-LV cavity dilation lack obstructive epicardial coronary artery disease, we hypothesized that vasodilator-induced subendocardial hypoperfusion resulting from microvascular dysfunction underlies this result. To test this hypothesis, we quantified myocardial blood flow (MBF) (subepicardial, subendocardial, and global MBF) and left ventricular ejection fraction (LVEF) in 104 patients with HC without significant coronary artery disease, using (13)NH3-PET...
September 15, 2016: American Journal of Cardiology
Lotta Walz, Anna K Jönsson, Brita Zilg, Carl Johan Östgren, Henrik Druid
AIMS/HYPOTHESIS: The aim of this study was to identify risk factors associated with confirmed fatal hyperglycaemia, which could predispose potentially preventable deaths in individuals on glucose lowering drugs. METHODS: A retrospective register-based case-control study conducted on a nationwide cohort with individuals who died due to hyperglycaemia as determined by forensic postmortem examination, in Sweden August 2006 to December 2012. Vitreous glucose was used to diagnose hyperglycaemia postmortem...
2016: PloS One
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Carlota Saldanha
Nitric oxide (NO) produced by endothelial cells interacts with erythrocyte through band 3 protein, being scavenged by haemoglobin. A signal transduction mechanism involving protein Gi and protein band 3 stimulates erythrocyte NO efflux when acetylcholine (ACh) binds to erythrocyte membrane acetylcholinesterase. Binding of normal plasma fibrinogen (Fib) levels, to erythrocyte membrane CD47 decreases the NO efflux. When high Fib concentration and ACh were present the efflux of NO from erythrocytes was normalized...
October 20, 2016: Clinical Hemorheology and Microcirculation
Jessica Lee, Richard Rosen
Diabetic retinopathy is a progressive microvascular disease that leads to increased vessel permeability, retinal ischemia, and retinal neovascularization. Optical coherence tomography angiography (OCTA) is a novel angiography technique that has the capability to advance our understanding of diabetic eye disease by providing high-resolution images of retinal and choroidal microvasculature blood flow and structure. Using OCTA, the vascular changes of diabetic retinopathy including microaneurysms, retinal non-perfusion, intraretinal microvascular abnormalities, and neovascularization can be clearly visualized...
December 2016: Current Diabetes Reports
Leslie A Blair, April K Haven, Natalie N Bauer
BACKGROUND: Microparticles (MPs) stimulate inflammatory adhesion molecule expression in systemic vascular diseases, however it is unknown whether circulating MPs stimulate localized ICAM-1 expression in the heterogeneically distinct pulmonary endothelium during pulmonary arterial hypertension (PAH). Pulmonary vascular lesions with infiltrating inflammatory cells in PAH form in the pulmonary arteries and arterioles, but not the microcirculation. Therefore, we sought to determine whether circulating MPs from PAH stimulate pulmonary artery endothelial cell-selective ICAM-1 expression...
October 20, 2016: Respiratory Research
Sharon L I Wong, Maria B Sukkar
Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein which regulates interactions between cells and their surrounding extracellular matrix (ECM), and thus governs fundamental cellular functions such as cell adhesion, proliferation and differentiation. SPARC also regulates the expression and activity of numerous growth factors and matrix metalloproteinases essential for ECM degradation and turnover. Studies in SPARC-null mice have revealed a critical role for SPARC in tissue development, injury and repair, and in the regulation of the immune response...
October 19, 2016: British Journal of Pharmacology
Hao-Lin Shen, Shu-Ping Yang, Kang-Jian Wang, Bei-Lei Huang, Wen-Bao Huang, Jin-Zhi Wu, Guo-Rong Lv
OBJECTIVE: Improvement in regional blood flow has been shown to ameliorate diabetic gastroparesis. We compared the gastric blood supply in diabetic patients with gastroparesis, with that in healthy subjects, by using contrast-enhanced ultrasound (CEUS). METHODS: Thirty healthy subjects and forty patients with diabetic gastroparesis were enrolled. The CEUS parameters of greater curvatures of the antrum (GCOA) and lesser curvatures of antrum (LCOA), including peak intensity (PI) and the area under the curve (AUC), were compared between the two groups...
October 19, 2016: British Journal of Radiology
Smeeta Sadar, Dipti Kaspate, Neeraj Vyawahare
Diabetic nephropathy is a serious microvascular complication and one of the main causes of end-stage renal disease. L-Glutamine (LG) is naturally occurring amino acids with antidiabetic and antioxidant potential. The aim of present investigation was to evaluate the potential of LG against streptozotocin (STZ)-induced diabetic nephropathy (DN) in laboratory rats. DN was induced in male Wistar rats (200-220 g) by intraperitoneal administration of STZ (55 mg/kg). Animals were treated orally with either distilled water (10 mg/kg) or LG (250, 500, and 1000 mg/kg) or Sitagliptin (5 mg/kg)...
October 19, 2016: Renal Failure
Elena Bartoloni, Giacomo Pucci, Francesca Cannarile, Francesca Battista, Alessia Alunno, Marco Giuliani, Giacomo Cafaro, Roberto Gerli, Giuseppe Schillaci
Although microvascular disease is a hallmark of systemic sclerosis (SSc), a higher prevalence of macrovascular disease and a poorer related prognosis have been reported in SSc than in the general population. The simultaneous assessment of prognostically relevant functional properties of larger and smaller arteries, and their effects on central hemodynamics, has never been performed in SSc using the state-of-the-art techniques. Thirty-four women with SSc (aged 61±15 years, disease duration 17±12 years, and blood pressure 123/70±18/11 mm Hg) and 34 healthy women individually matched by age and mean arterial pressure underwent the determination of carotid-femoral (aortic) and carotid-radial (upper limb) pulse wave velocity (a direct measure of arterial stiffness), aortic augmentation (a measure of the contribution of reflected wave to central pulse pressure), and aortobrachial pulse pressure amplification (brachial/aortic pulse pressure) through applanation tonometry (SphygmoCor)...
October 17, 2016: Hypertension
Masami Tanaka, Takeshi Nishimura, Risa Sekioka, Toshihide Kawai, Shu Meguro, Junichiro Irie, Yoshifumi Saisho, Hiroshi Itoh
OBJECTIVE: This cross-sectional study was conducted to assess the association between serum albumin concentration (SAC) and microvascular complications in hypertensive patients complicated by type 2 diabetes mellitus (T2DM). DESIGN AND METHOD: Four hundred and ninety five hypertensive patients (331 men) with T2DM were investigated. SAC was compared between patients with and without microvascular complications (retinopathy, nephropathy, and neuropathy). Then, logistic regression analyses were performed to examine the effects of various factors on microvascular diseases, and the following factors were considered as independent variables: SAC, gender, age, duration of diabetes, body mass index (BMI), systolic blood pressure (SBP), HbA1c, eGFR, LDL-cholesterol, and triglyceride...
September 2016: Journal of Hypertension
Ruan Kruger, Moliehi Mothae, Wayne Smith
OBJECTIVE: Cigarette smoking weakens the antioxidant defence system and is considered a lifestyle risk factor contributing to cardiovascular disease progression. Little information exists on these links in non-smoking versus smoking populations. We aimed to explore the associations of oxidative stress with markers of vascular function in a young, normotensive bi-ethnic population. DESIGN AND METHOD: We included 237 non-smokers (108 black and 129 white) and 145 smokers (78 black and 67 white) from South Africa between ages 20 and 30 years...
September 2016: Journal of Hypertension
Tien Wong
The vasculature in the retina can be viewed directly and non-invasively in vivo, offers a unique perspective of the human microvasculature, and therefore the ability to understand early changes, processes, pathways and consequences of hypertension. In the past 15 years, advances in high resolution digital retinal photography and automated or semi-automated computer image software have been applied to measure and quantify a variety of retinal microvascular parameter, including retinal arteriolar and venular caliber, tortuosity, branching patterns and fractal dimensions...
September 2016: Journal of Hypertension
Junichiro Hashimoto
The central aorta constitutes the main trunk of the systemic arterial tree. It dilates passively with cardiac ejection during systole and then constricts with its recoil function during diastole, thereby regulating blood pressure and blood flow. The central pulsatile hemodynamics affects local hemodynamics within as well as downstream of the aorta (e.g., end organs).The aorta progressively stiffens and dilates with advancing age, and such age-dependent change is accelerated by hypertension. According to the law of Laplace, wall stress depends on the diameter and pressure of the blood vessel...
September 2016: Journal of Hypertension
Fang-Fei Wei, Nadja E A Drummen, Lutgarde Thijs, Lotte Jacobs, Marjolein Herfs, Cynthia Van't Hoofd, Cees Vermeer, Jan A Staessen
Vitamin-K-dependent carboxylation of matrix Gla protein (MGP) protects the macrocirculation against calcification. We recently reported in a multiethnic population study that the estimated glomerular filtration rate, a microvascular trait, decreased and the risk of chronic kidney disease increased with higher circulating levels of inactive dephospho-uncarboxylated MGP, a marker of vitamin K deficiency. These findings highlighted the possibility that vitamin K might have a beneficial effect on the renal microcirculation...
September 2016: Pulse (Basel, Switzerland)
Leroy L Cooper, Gary F Mitchell
BACKGROUND: Aortic stiffness is associated with cardiovascular and cerebrovascular events and cognitive decline. This mini-review focuses on relations of aortic stiffness with microvascular dysfunction and discusses the contribution of abnormal pulsatile hemodynamics to cerebrovascular damage and cognitive decline. We also provide a rationale for considering aortic stiffness as a putative and important contributor to memory impairment in older individuals. SUMMARY: Aging is associated with stiffening of the aorta but not the muscular arteries, which reduces wave reflection and increases the transmission of pulsatility into the periphery...
September 2016: Pulse (Basel, Switzerland)
Arun Gopi, Placid Sebastian, C D Ramakrishna
Isolated ventricular noncompaction (IVNC) is an unclassified cardiomyopathy characterized by prominent intraventricular trabeculations separated by deep intertrabecular recesses. Although microvascular dysfunction is known, myocardial infarction is rare and usually seen as a consequence of coincidental coronary artery disease. We report the case of a 19-year-old male patient who presented to us with symptoms and signs of heart failure. Echocardiography revealed IVNC with severe left ventricular dysfunction...
September 2016: Indian Heart Journal
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