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Re-orchestration of blood flow by micro-circulations.

ABSTRACT: Haemoglobin Video Imaging (HVI) demonstrates conjunctival and episcleral blood flow in man with the resolution of a single erythrocyte. A new method for establishing vessel hierarchy in micro-circulations is described, which recognises either delivery or drainage vessels and references vessel order to the capillary. These tools have been used to characterise blood flow.Anterior ciliary arteries show pulsatile variation in diameter. The episcleral arterial circle that they supply has functional apices with pulsatile flow reversal. Perfusion fields overlap: a single delivery vessel may project to many drainage vessels and vice-versa. Some vascular pathways remained inactive throughout a 1?min angiogram.Small conjunctival delivery vessels have laminar flow, but advancing luminal constrictions are often observed within the blood column. Laminar flow is lost in low-order drainage vessels where erythrocytes aggregate, but quickly recovers, new striae being added to the blood column at each confluence. Aqueous forms a discrete column, which centralises in episcleral drainage vessels.There is strong evidence that the luminal constrictions in small delivery vessels propel blood by peristalsis: they form spontaneously, remote from bifurcations; a single vessel may have multiple constrictions; they truly narrow the lumen, rarely contributing volume to post-capillary venules; they can proceed faster than the vessel contents; they never enter the drainage system; the trailing edges of erythrocyte boluses usually taper. They are rhythmically aligned with cardiac systole.While blood is transported to the periphery by the heart, it is actively transferred through tissues by peristalsis in small delivery vessels.

SUBMITTER: Meyer PAR

PROVIDER: S-EPMC5811746 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Re-orchestration of blood flow by micro-circulations.

Meyer P A R PAR

Eye (London, England) 20180119 2

Haemoglobin Video Imaging (HVI) demonstrates conjunctival and episcleral blood flow in man with the resolution of a single erythrocyte. A new method for establishing vessel hierarchy in micro-circulations is described, which recognises either delivery or drainage vessels and references vessel order to the capillary. These tools have been used to characterise blood flow.Anterior ciliary arteries show pulsatile variation in diameter. The episcleral arterial circle that they supply has functional a ...[more]

PMID: 29350685

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Project description:BackgroundOur previous research and other studies with radiotracers showed evidence of a centripetal drainage pathway, separate from blood or lymphatic vessels, that can be visualized when a small amount of low molecular weight tracer is injected subcutaneously into a given region on skin of humans. In order to further characterize this interesting biological phenomenon, animal experiments are designed to elucidate histological and physiologic characteristics of these visualized pathways.MethodsMultiple tracers are injected subcutaneously into an acupuncture point of KI3 to visualize centripetal pathways by magnetic resonance imaging or fluorescein photography in 85 healthy rabbits. The pathways are compared with venography and indirect lymphangiography. Fluid flow through the pathways is observed by methods of altering their hydrated state, hydrolyzing by different collagenases, and histology is elucidated by optical, fluorescein and electron microscopy.ResultsHistological and magnetic imaging examinations of these visualized pathways show they consist of perivenous loose connective tissues. As evidenced by examinations of tracers' uptake, they appear to function as a draining pathway for free interstitial fluid. Fluorescein sodium from KI3 is found in the pathways of hind limbs and segments of the small intestines, partial pulmonary veins and results in pericardial effusion, suggesting systematical involvement of this perivenous pathway. The hydraulic conductivity of these pathways can be compromised by the collapse of their fiber-rich beds hydrolyzed by either of collagenase type I, III, IV or V.ConclusionsThe identification of pathways comprising perivenous loose connective tissues with a high hydraulic conductivity draining interstitial fluid in hind limbs of a mammal suggests a potential drainage system complementary to vascular circulations. These findings may provide new insights into a systematically distributed collagenous connective tissue with a circulatory function and their potential relevance to the nature of acupuncture meridians.

Dataset Information

Re-orchestration of blood flow by micro-circulations.

Publications

Re-orchestration of blood flow by micro-circulations.

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