Clinical Hemorheology and Microcirculation - Volume 29, issue 3-4

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 139-140, 2003

Authors: Pries, A.R. | Secomb, T.W.

Article Type: Research Article

Abstract: The main function of the microvasculature is the controlled exchange of materials with surrounding tissues. This necessitates a large vessel surface established by a high number of vessels with small diameters and thus an inherently high individual resistance to flow. The hydrodynamic resistance of a microvascular network with given angioarchitecture depends on the apparent viscosity of blood flowing in the microvessels. Apparent viscosity declines with decreasing diameter (the Fahraeus–Lindqvist effect) and is minimal at diameters of about 5–7 μm due to the optimal alignment of red cells with the flow. In vivo, a number of additional phenomena influence blood rheology …and network hemodynamics. The distribution of blood flow and red cell flux within networks is influenced by the mechanics of red cell motion at individual diverging bifurcations (phase‐separation effect). Furthermore, recent studies have revealed the presence of a thick endothelial surface layer (∼0.5 μm) on the luminal surface of microvessels which is attached to the endothelial glycocalyx. This layer modulates flow resistance and may be relevant for a number of other processes such as inflammatory responses and blood coagulation. Information on microvascular rheology can be used to develop mathematical models of network hemodynamics and vascular adaptation to the local environment (angioadaptation), to investigate the complex interrelated mechanisms which establish and maintain functionally adequate microvascular networks. Show more

Keywords: Blood flow, endothelial surface layer, angioadaptation, microvascular networks, model simulation

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 143-148, 2003

Authors: Niimi, Hideyuki

Article Type: Research Article

Abstract: Pharmacological induction of angiogenesis is a new treatment of cerebrovascular insufficiency without surgical treatment. It is an urgent task to investigate the dynamic process of angiogenesis and of the microvascular perfusion of the cerebral neoplastic tissue in vivo. The present study is concerned with microcirculatory aspects of cerebral neocapillaries in vivo. A novel model of cerebral angiogenesis was developed by inducing cerebral neocapillaries in mice using growth factors such as basic fibroblast growth factor (bFGF) and platelet‐derived growth factor (PDGF). By a direct observation of the neocapillary microcirculation under a fluorescence videomicroscope, the neocapillary density, diameter and red cell velocity …were measured to evaluate the development and remodeling of the neocapillaries with the number of days after incubation. The neocapillary response to topically applied acetylcholine (ACh) was examined by measuring changes in the diameter and red cell velocity. It was shown that PDGF‐induced neocapillaries was dilated in response to ACh on day 28 after incubation, while bFGF‐induced neocapillaries was not. Furthermore, the neocapillary pericytes were observed using confocal laser microscopy, based on the fluorescence immunohistochemical images of the neoplastic tissue. Several pericytes, stained with anti‐NG2 , appeared in the neocapillaries. It was suggested that these pericytes might be recruited in the neocapillaries to regulate blood flow without vascular smooth muscle. Show more

Keywords: Cerebral angiogenesis, fluorescence videomicroscopy, growth factor, neocapillary regulation, pericytes

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 149-156, 2003

Authors: Abarquez, Jr., Ramon F. | Cinco, Jude Erric L.

Article Type: Research Article

Abstract: Microcirculation conduit, distribution, exchange and reception vessels usually retain a demand‐dependent vascular–tissue match as well as a nutrient friendly capillary–matrix tissue match. Various stimuli can initiate a vascular–capillary matrix‐tissue mismatch. Counter‐regulatory mechanisms result in hyperplasia or apoptosis. Microvascular disease (MVD) as a consequence or outcome of supply–demand mismatch has clinical therapeutic and prognostic implications in the hypertensive syndrome and coronary artery disease (CAD) cases. Recognition of the role of apoptosis and MVD may initiate a paradigm shift in clinical practice. Digitalis and other anti‐hypertensive agents have anti‐apoptotic action and MVD blunting effects that can control LVH development to reduce congestive …heart failure (CHF) progression. Show more

Keywords: Apoptosis, microvascular diseases, cardiovascular diseases, hypertension

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 157-165, 2003

Authors: Oda, Masaya | Yokomori, Hiroaki | Han, Jing‐Yan

Article Type: Research Article

Abstract: Hepatic microvasculature receives blood from two types of afferent vessels: the terminal portal venule (TPVn) and the terminal hepatic arteriole (THAo). The TPVns directly connect with the capillary bed in the liver parenchyma, which is referred to as sinusoids. Hepatic arterial blood pours into the hepatic sinusoids not only indirectly via the anastomosis between the THAo and the portal venule (PVn), but also directly through the THAo or the capillaries derived from the arterial capillary network around the bile duct. From a regulatory point of view, the hepatic arterial system is considered to be supplementary, but hepatic arterial flow is …essential for supplying oxygen to sinusoidal blood flow as well as to the bile ducts, portal venules and nerves in the portal tract. The main regulators of hepatic sinusoidal blood flow are present in the portal venous system. By intravital and scanning electron microscopy, it is evident that a potent vasoconstrictor endothelin (ET)‐1 causes a contraction of the SEF via the ETB receptors, as well as a significant contraction of the PVn and TPVn, resulting in an increase in sinusoidal and pre‐sinusoidal microvascular resistance. This phenomenon implies that the TPVn, particularly the transitional part to the sinusoid, would provide an essential regulatory site for hepatic sinusoidal blood flow as an inlet sphincter‐like function. The endothelial cell linings along the hepatic sinusoids are characterized by the presence of a large number of sieve plate‐like pores, 100 nm in diameter, i.e. the sinusoidal endothelial fenestrae (SEF). The SEF are dynamic structures, forming the racemose invaginations of the endothelial plasma membrane across the endothelium, and regulating not only the permeability of hepatic sinusoids, but also the sinusoidal blood flow by the Ca++ ‐actomyosin‐mediated contraction and dilatation of the SEF. Our recent immunoelectron microscopic and Western blot studies have revealed that caveolin‐1, i.e. the principal structural protein of caveolae, and endothelial nitric oxide synthase (eNOS) co‐exist in the plasma membrane of the SEF, implying that the SEF may correspond to a permanent (stationary) type of fused and interconnected caveolae, thus contributing to the local control of hepatic sinusoidal blood flow by the regulation of NO synthesis. Show more

Keywords: Hepatic microcirculation, hepatic arterioles, intravital microscopy, sinusoidal endothelial fenestrae, caveolae

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 167-182, 2003

Authors: Futrakul, Prasit | Siriviriyakul, Prasong | Patumraj, Suthiluk | Bunnag, Srichitra | Kulaputana, Ornanong | Futrakul, Narisa

Article Type: Research Article

Abstract: Glomerular endothelial cell (GEC) dysfunction due to oxidative stress and enhanced proinflammatory cytokines plays an important role in inducing proteinuria and procoagulant activity, namely blood hypercoagulability, hyperviscosity and local intravascular coagulation and altered hemorheology in NS. A dysfunctioning GEC releases fewer endothelium‐dependent vasodilators but produces more vasoconstrictors. Severe intrarenal hemodynamic alteration associated with hemodynamic maladjustment with preferential constriction at the efferent arteriole has been uniquely implicated in severe GN and NS‐FSGS. Such a constriction exerts three significant hemodynamic impacts. Proximal to the efferent arteriolar constriction, it induces (i) an overestimated GFR due to hyperfiltration and (ii) an elevated intraglomerular hydrostatic …pressure. Distal to the efferent arteriolar constriction, it (iii) exaggeratedly reduces PTCF which correlates with the TIF. Show more

Keywords: Renal disease, glomerulonephritides, nephrosis, hemodynamics

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 183-187, 2003

Authors: Zhang, Hong‐Gang | Xiu, Rui‐Juan

Article Type: Research Article

Abstract: A new technique is sweeping the world, and changing the course of human work and life. It is impacting upon models, methods and the development of medical research. In the development of this new technique, a huge quantity of experimental research and clinical practice has proved that many human diseases have a close relationship to pathological changes that take place in the microvascular system. It has been proven that the microvascular system is the target for studying disease development and the treatment of disease. Many studies have shown that successful pathogenesis and pathological research must be aimed at understanding the …key proteins in cells, organs and systems, as well as investigating their interaction, and finding out how these proteins change under disease conditions. This paper reviews the current status of microvascular medicine and proteomics. Show more

Keywords: Apoptosis, angiogenesis, microvascular medicine, proteomics

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 189-192, 2003

Authors: Niimi, Hideyuki | Han, Jing‐Yan | Patumraj, Suthiluk

Article Type: Research Article

Abstract: Asian traditional medicine (ATM) (herbal medicine, acupuncture or moxibution) has gained some popularity among communities in Asia, but there are still few evidences to prove the effectiveness of such therapeutic measures. A symposium was held with aim at the effectiveness of Asian traditional therapies in views of in vivo microcirculation. This report is concerned with the symposium, including Asian activities for ATM.

Keywords: Asian traditional medicine (ATM), herbal medicine, microcirculation

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 195-198, 2003

Authors: Bernas, Gloria de Castro

Article Type: Research Article

Abstract: Angiogenesis offers an enormous potentials for therapeutic intervention of many disorders afflicting mankind at present. With the identification of the major molecular players involved in the sequence of events leading to the formation of new blood vessels from pre‐existing capillaries, inhibition or induction of the process may now be regulated. Bioactive compounds from natural sources may be used as regulatory agents. Inhibition of angiogenesis can control diseases characterized with excessive blood vessel growth like cancer, arthritis, psoriasis and diabetes retinopathy. Stimulation of angiogenesis would be favorable in the treatment of ischemic disorders and tissue engineering. An increasing number of bioactive …compounds from natural sources and whose chemical structures have already been elucidated are reported as either potential inhibitors or inducers of angiogenesis. Drug development from natural products is a fast‐emerging field that needs to be supported to provide people with more readily available and affordable healthcare. Show more

Keywords: Angiogenesis, angiotherapeutics, neovascularization, natural products, bioactive compounds

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 199-203, 2003

Authors: Futrakul, Narisa | Boonyen, Mongkolsilp | Patumraj, Suthiluk | Siriviriyakul, Prasong | Tosukhowong, Piyaratana | Futrakul, Prasit

Article Type: Research Article

Abstract: Glomerular endothelial dysfunction is believed to be responsible for the proteinuria and nephronal damage, namely tubulointerstitial fibrosis and glomerulosclerosis, observed in severe nephrosis such as focal segmental glomerulosclerosis. A dysfunctioning glomerular endothelium is likely to be induced by oxidative stress and oxidized LDL as well as altered immunocirculatory balance with a defective anti‐inflammatory pathway. A defective release of vasodilator inconjunction with enhanced production of angiotensin II induces hemodynamic maladjustment by preferential constriction at the efferent arteriole. Such a hemodynamic maladjustment exerts two significant hemodynamic impacts. Close to the efferent constriction, it induces intraglomerular hypertension and glomerulosclerosis. Far from the efferent …constriction, it reduces peritubular capillary flow, which eventually leads to tubulointerstitial fibrosis. Treatment with a vasodilator improves the hemodynamic maladjustment but does not completely suppress proteinuria. A successful suppression of proteinuria is accomplished by using Ganoderma lucidum and vitamins C and E. The beneficial effect of Ganoderma lucidum appears to be multifactorial, including the modulation of immunocirculatory balance, antilipid, vasodilator, antiplatelet and improved hemorheology. Together with vitamins C and E, this helps to neutralize oxidative stress and suppress the toxic effect to the glomerular endothelial function. Show more

Keywords: Steroid resistant nephrosis, hemodynamic maladjustment, oxidative stress, vasodilators, antioxidant, Ganoderma lucidum

Citation: Clinical Hemorheology and Microcirculation, vol. 29, no. 3-4, pp. 205-210, 2003