血流限制训练改善认知功能的机制及应用方案

背景：血流限制训练是阻力训练领域的一种新型训练方式,血流限制训练在对肌肉力量、质量和躯体能力产生影响的同时可以诱导激活神经可塑性和认知功能等相关信号通路。然而,目前的研究尚未系统综述血流限制训练对不同人群认知能力的影响,对血流限制训练改善认知功能的神经生物学机制缺乏全面认识,且对血流限制训练的应用方案尚不完全清楚。目的：对国内外现有的血流限制训练对不同人群认知功能影响的试验研究进行梳理,深度剖析潜在的神经生物学机制,归纳总结以往研究应用血流限制训练改善认知功能的合理性方案,旨在为安全有效地应用该技术提供理论支撑和实践指导。方法：计算机检索PubMed、Web of Science和中国知网等数据库,检索时间设定为各数据库建库至2022年10月,中文检索词包括“血流限制训练、加压训练、血流限制疗法、血流限制、加压血流阻滞训练、血流阻滞、认知功能、认知能力”,英文检索词包括“Blood Flow Restricting Therapy,KAATSU training,KAATSU volume,Resistance training,BFR Therapy,BFRT,Blood Flow ...     

Structural response of skeletal muscle mitochondria to experimental deep hypothermia

Bulletin of Experimental Biology and Medicine -     

Left atrial distension and intrarenal blood flow distribution in conscious dogs

The effect of hypoxia on the electrical and mechanical activity of rat portal vein smooth muscle were investigated using intracellular microelectrode technique in combination with contraction force measurements. In control conditions the resting potential of the muscle cells was –58.0 ±0.1 mV (mean±S.E.). Bursts of action potentials, 5–10s long, appeared at regular intervals (2–3/min) in association with phasic contractions. In hypoxia (P _O2, at about 10 mm Hg) there was a marked decrease in force and, often, a moderate increase in rate of the spontaneous contractions. Electrically, these changes corresponded to a decrease in length and an increase in frequency of the bursts of action potentials. The general level of membrane polarization and individual action potentials were not affected. In prolonged hypoxia there was a tendency towards dissociation of the electrical and mechanical activities. Increasing [K⁺]₀ or reducing [Na⁺]₀ produced a restoration of the hypoxically depressed force development. Qualitatively similar resuts with respect to the depression of myogenic activity by hypoxia, and its alleviation in decreased [K⁺]₀ and reduced [Na⁺]₀, were obtained in low Ca (1 mM) solutions. The effects of hypoxia, and their variation with [K⁺]₀ and [Na⁺]₀, could be explained on the basis of pH dependent electro-mechanical uncoupling.     

The effect of cooling on the responses of splenic capsular and vascular smooth muscle to nerve stimulation in the dog

Field stimulation of strips of canine splenic capsule and splenic artery suspended in an organ bath causes in both a contraction that is enhanced by cooling from 37°C to 27°C. This finding contrasts with that from the isolated perfused canine spleen in which cooling to 27°C enhanced the vascular response to splenic nerve stimulation but depressed the capsular response. The results of experiments to resolve the apparent discrepancy in the capsular smooth muscle response to stimulation indicate that the reduced response in the perfused spleen probably results from the capsular smooth muscle fibres being less optimally placed on their length: tension curve at 27°C when spleen volume is less. There is thus no need to postulate any fundamental difference in properties between the smooth muscles from the two intrasplenic distributions.     

Dynamic exercise in man as influenced by experimental restriction of blood flow in the working muscles

The effects of reduced muscle perfusion pressure on dynamic exercise performance and cardiovascular and respiratory functions were investigated. Eight subjects were studied during supine cycle ergometry at stepwise increasing workloads until exhaustion with and without the legs exposed to a supra-atmospheric pressure of 50 mmHg (Leg Positive Pressure, LPP), a novel and convenient means of reducing the perfusion pressure in the working muscles. In the LPP condition exercise performance was reduced by 40% which, judging from assessments of perceived exertion, was due to premature muscle fatigue, indicating local or overall underperfusion of the working muscles. At any given work load, the arterial pressure response was considerably stronger during LPP than in the control condition. LPP also caused greater increases in blood lactate concentration and pulmonary ventilation, the differences from control increasing with the work load. Furthermore, the ventilatory equivalent for O₂ at a given work load was markedly higher in the LPP than in the control condition, while exercise-induced decreases in end-tidal P_CO2 were considerably exaggerated by LPP. The augmented pressor response during flow-restricted exercise, together with the strong ventilatory response which was out of proportion to overall O₂ uptake, suggests increased activation of muscle chemoreflexes by accumulation of metabolic end products, the increased pressor response tending to reduce the local flow error in the working muscles.     

Systematic Analysis of the Smooth Muscle Wall Phenotype of the Pharyngeal Arch Arteries During Their Reorganization into the Great Vessels and Its Association with Hemodynamics

Early outflow morphogenesis is a critical event in cardiac development. Understanding mechanical and molecular based morphogenetic relationships at early stages of cardiogenesis is essential for the advancement of cardiovascular technology related to congenital heart defects. In this study, we pair molecular changes in pharyngeal arch artery (PAA) vascular smooth muscle cells (VSMCs) with hemodynamic changes over the course of the same period. We focus on Hamburger Hamilton stage 24–36 chick embryos, using both Doppler ultrasound and histological sections to phenotype PAA VSMCs, and establish a relationship between hemodynamics and PAA composition. Our findings show that PAA VSMCs transition through a synthetic, intermediate, and contractile phenotype over time. Wall shear stress magnitude per arch varies throughout development. Despite distinct hemodynamic and fractional expression trends, no strong correlation was found between the two, indicating that WSS magnitude is not the main driver of PAA wall remodeling and maturation. While WSS magnitude was not found to be a major driver, this work provides a basic framework for investigating relationships between hemodynamic forces and tunica media during a critical period of development. Anat Rec, 302:153–162, 2019. © 2018 Wiley Periodicals, Inc.     

Reduced embryonic blood flow impacts extracellular matrix deposition in the maturing aorta

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Role of mechanical factors in governing muscle blood flow

This study evaluates how mechanical factors impact cardiac output at the systemic level, and how mechanical factors influence muscle blood flow at the local level. Importantly, the two are intertwined; events that work locally in the periphery to augment muscle blood flow can also act centrally to contribute to the development of a high cardiac output.     

Norepinephrine and isoprenaline induced changes of peripheral blood flow acceleration caused by changes of cardiac inotropy

Summary In anesthetized dogs the norepinephrine (NE) and isoprenaline (ISO) (1–1024 ng/kg i.v.)-induced increase of maximum peripheral flow acceleration (celiac artery, cranial mesenteric artery, renal artery, and femoral artery) and the changes of the maximum first derivative of arterial pressure were compared with the increases of maximum ascending aortic flow acceleration and maximum first derivative of left ventricle pressure (LV dP/dt max).The maximum effect of each dose on maximum acceleration of flows (dF/dt max) and maximum first derivative of pressures (dP/dt max) occurred simultaneously for all variables. The effect was dose-dependent. Sensitivity was similar for NE (D₅₀:2256–512 ng/kg) and for ISO (D₅₀: 128–256 ng/kg).We demonstrated that other variables than inotropic action (heart rate, left ventricular end diastolic pressure and diastolic aortic pressure) played only a minor role in the increases of LV dP/dt max in our studies.In contrast with the uniform response of dF/dt max and dP/dt max, the reaction of peripheral vascular resistance varied. In particular in the gastrointestinal tract the resistance could either be increased (NE, D₅₀: 115 ng/kg) or decreased (ISO, D₅₀: 15 ng/kg). Gastrointestinal resistance was a more sensitive variable for catecholamine stimulation than dF/dt max and dP/dt max.The data show that under the present experimental conditions enhancement of peripheral flow acceleration induced by NE and ISO is due to increase of cardiac inotropy.Supported by the Foundation for Medical Research FUNGO     

An investigation of blood flow behavior and hemolysis in artificial organs

In our previous study, in vitro hemolysis tests showed that collision flow against wall roughness had an effect on hemolysis when the flow velocity was more than 3 m/s and surface roughness was more than Ra = 1.54 microm. However, the specific portion of the flow on the wall that induced hemolysis was not clarified. Therefore, the purpose of this study was to present the relationship between flow behavior and hemolysis by means of in vitro tests and computational fluid dynamics (CFD) analysis. We investigated the relationship between the location of surface roughness and hemolysis. In CFD, we investigated the flow behavior on the wall. The highest rate of hemolysis was observed in a region around the center of the surface roughness on the bottom plate. On CFD analyses, the flow behavior included the highest wall shear stress (304 Pa) and the highest flow acceleration (2.8 m/s2) around the center of the bottom plate. Therefore, it is concluded that the causes of hemolysis during collision flow depend upon wall shear stress and flow acceleration.     

No relation between atrial natriuresis and renal blood flow in conscious dogs

Summary Conscious dogs were used to study whether changes in total renal hemodynamics are responsible for diuresis and natriuresis during an experimental increase in left atrial pressure (LAP). To ensure a controlled dietary sodium intake, the dogs (n=8) were chronically kept on ahigh or alow sodium intake diet (HSI; LSI). After the dogs had completely recovered from surgery (carotid loop, thoracotomy, flank incision), LAP was increased by about 10 cm H₂O for 60 min by tightening a purse string around the mitral annulus (51 expts). Mean urine volume (V) increased in both groups to a comparable degree. Mean sodium excretion increased somewhat more in HSI dogs, but remained elevated in LSI dogs after the LAP increase. Renal blood flow (electromagnetic flow transducer) and inulin clearance did not change. Renal vascular resistance (RVR) increased by about 20% (HSI) and 15% (LSI). — When the induced LAP increase was terminated, V decreased. RVR decreased in HSI dogs by about –11% and in LSI dogs by about –6% below control values.—It is concluded that volume regulatory mechanisms induced by an experimental LAP increase operate independently of changes in total renal blood flow.The Arbeitsgruppe Experimentelle Anästhesie is member of the Research Group Autonomic Regulations Freie Universität Berlin     

Effects on the renal artery blood flow during the intra-aortic balloon pumping was used

INTRODUCTIONTheintra-aorticballoonpumping(IABP)isanimportantmethodtoassistthebeauintheclinic.ThismethodisspecialtogiveemergencytrCdrieflttOtheischemiccardiopathyandthecardiogenicshock,andtoimprovehemodynamiceffects.ThecuxativeeffectsofIABPareveryobviousll].Theaamalexperimelltwasdesignedtoexploretheeffectsoftheintra-aofticballoonontherenalemerybloodflowdchngpumping.MATERJALANDMETHODSaamalpreparationsfTwentyadultdogsofeithersexweighing15-20kgwereanesthetizedwithketalnine(200mgi.m…     

Non-homogeneous blood flow distribution in the rabbit tenuissimus muscle Differential control of total blood flow and capillary perfusion

Structural and functional relationships underlying the blood flow distribution in the rabbit tenuissimus muscle were examined by means of intravital microscopy. A majority of the main feeding arterioles (transverse arterioles) continued into adjacent connective tissue, after giving off branches (terminal arterioles) within the muscle tissue to supply the muscle capillaries. The transverse arterioles thus supplied two vascular areas, although the major part of the arteriolar flow, under normal resting conditions, was distributed to the muscle capillaries—a flow fraction over which the terminal arterioles exerted ultimate control. The fractional distribution of the blood flow between muscle and connective tissue was determined by the relative contributions of the transverse and terminal arterioles to the vascular resistance. These arteriolar segments showed a differential response to an increase in oxygen availability (elevated ambient pO₂), resulting in a total reduction of muscle capillary flow, but no concomitant change in the flow to connective tissue. A decrease in perfusion pressure, on the other hand, led to similar flow changes in the muscle and connective tissue circulation, which was attributed to proportionate resistance changes in the transverse and terminal arterioles. Differences between the larger transverse and smaller terminal arterioles in their sensitivity to various stimuli may form a functional basis for a differential control of arteriolar blood supply and capillary perfusion in this muscle.     

钙激活性氯离子通道与高肺血流性肺动脉高压

Pulmonary hypertension induced by high pulmonary blood flow involves a variety of complex mechanisms, including endothelial damage, pulmonary artery smooth muscle relaxation-contraction disorder and vascular remodeling. Besides, the factor of ion channels in pulmonary artery smooth muscle cells is also highly correlated to vasoconstriction. In recent years, many studies have shown that activation of Ca²⁺-activated Cl^- channels is responsible for the membrane depolarization of pulmonary artery smooth muscle cells, and plays an important role in the regulation of vascular tone and vasoconstriction. This article reviews the biophysical and pharmacological characteristics of Ca²⁺-activated Cl^- channels as well as the influence of Ca²⁺-activated Cl^- channels in high pulmonary blood flow-induced pulmonary hypertension.     

Intracellular free calcium concentration / force relationship in rabbit inferior vena cava activated by norepinephrine and high K+

The changes in isometric force and the underlying fluctuations in intracellular free calcium concentration ([Ca²⁺]_i) were monitored simultaneously in thin sheets of rabbit inferior vena cava loaded with the fluorescent Ca²⁺ indicator fura-2. In resting tissues bathed in physiological saline solution, the estimated [Ca²⁺]_i was approximately 105 nM. The -adrenergic agonist norepinephrine (10 M) caused an initial rise in [Ca²⁺]_i to 264 nM during force development, which dropped to 216 nM during force maintenance. The maintained norepinephrine-induced increase in force and [Ca²⁺]_i was reversed in Ca²⁺-free (2 mM EGTA) solution. Membrane depolarization by high K⁺ (80 mM) significantly increased [Ca²⁺]_i to 234 nM. Compared to norepinephrine, high K⁺ caused about the same steady-state increase in [Ca²⁺]_i, but a smaller increase in force. [Ca²⁺]_i/force curves were constructed at different concentrations of extracellular Ca²⁺, with either norepinephrine or high K⁺ as a stimulant. The curve generated with norepinephrine was located to the left of that generated with high K⁺.     

血管P2受体的功能及其与某些血管疾病的关系

P2受体分为配体门控离子通道型P2X受体和G蛋白偶联型P2Y受体。血管内皮细胞及平滑肌细胞有多种P2X和P2Y受体亚型表达。嘌呤信号与动脉粥样硬化、脑血管老化及血管重塑等血管疾病有关,并可能为治疗与血管有关疾病提供新的治疗靶点。     

Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images

Magnetic resonance images of the anal canal show small, circular, low-intensity areas arranged in a row and a high-intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0–1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low- and high-intensity areas. Clin. Anat. 33:619–626, 2020. © 2019 Wiley Periodicals, Inc.