Objective: The aim of the study was to assess the geometric characteristics of rat pial microcirculation and describe the vessel bifurcation patterns by 'connectivity matrix'.
Methods: Male Wistar rats were used to visualize pial microcirculation by a fluorescent microscopy technique through an open cranial window, using fluorescein isothiocyanate bound to dextran (molecular weight 70 kDa). The arteriolar network was mapped by stop-frame images. Diameters and lengths of arterioles were measured with a computer-assisted method. Pial arterioles were classified according to a centripetal ordering scheme (Strahler method modified according to diameter) from the smallest order 1 to the largest order 5 arterioles in the preparation. A distinction between arteriolar segments and elements was used to express the series-parallel features of the pial arteriolar networks. A connectivity matrix was used to describe the connection of blood vessels from one order to another.
Results: The arterioles were assigned 5 orders of branching by Strahler's ordering scheme, from order 1 (diameter: 16.0 +/- 2.5 microm) to order 5 (62 +/- 5.0 microm). Order 1 arterioles gave origin to capillaries, assigned order 0. The diameter, length and branching of the 5 arteriolar orders grew as a geometric sequence with the order number in accordance with Horton's law. The segments/elements ratio was the highest in order 4 and 3 arterioles, indicating the greatest asymmetry of ramifications. Finally, the branching vessels in the networks were described in details by the connectivity matrix. Fractal dimensions of arteriolar length and diameter were 1.75 and 1.78, respectively.
Conclusions: The geometric characteristics of rat pial microcirculation indicate that distribution of vessels is fractal. The connectivity matrix allowed us to describe the number of daughter vessels spreading from parent vessels. This ordering scheme may be useful to describe vessel function, according to diameter, length and branching.
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http://dx.doi.org/10.1159/000109078 | DOI Listing |
Int J Mol Sci
October 2024
Department of Translational Medicine and New Technologies in Medicine and Surgery, University of Pisa, 56127 Pisa, Italy.
Acute and chronic hypertension causes cerebral vasculopathy, increasing the risk of ischemia and stroke. Our study aimed to compare the effects of arterial pressure reduction on the pial microvascular responses induced by hypoperfusion and reperfusion in spontaneously hypertensive Wistar rats, desamethasone-induced hypertensive Wistar rats and age-matched normotensive Wistar rats fed for 3 months with a normal diet or normal diet supplemented with L-arginine or Taurisolo or L-arginine plus Taurisolo. At the end of treatments, the rats were submitted to bilateral occlusion of common carotid arteries for 30 min and reperfusion.
View Article and Find Full Text PDFMicrocirculation
October 2024
Department of Autonomic Neuroscience, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan.
Objective: Intragastric administration of ninjin'yoeito (NYT), a traditional Japanese herbal medicine, reportedly prevents the decrease in baseline cerebral blood flow (CBF) in the cortex following gastric administration of water. We investigated the effect of NYT on baseline and dynamic changes in cerebral cortical arteriole diameter.
Methods: Urethane-anesthetized mice were intragastrically administered 1 g/kg NYT or distilled water (DW).
Neurosurgery
August 2024
Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei , Taiwan.
Background And Objectives: Hydrocephalus is characterized by progressive enlargement of cerebral ventricles, resulting in impaired microvasculature and cerebral hypoperfusion. This study aimed to demonstrate the microvascular changes in hydrocephalic rats and the effects of cerebrospinal fluid (CSF) release on cerebral blood flow (CBF).
Methods: On postnatal day 21 (P21), male Wistar rats were intracisternally injected with either a kaolin suspension or saline.
Microcirculation
April 2024
Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA.
Objective: The role of cerebral microvasculature in cognitive dysfunction can be investigated by identifying the impact of blood flow on cortical tissue oxygenation. In this paper, the impact of capillary stalls on microcirculatory characteristics such as flow and hematocrit (Ht) in the cortical angioarchitecture is studied.
Methods: Using a deterministic mathematical model to simulate blood flow in a realistic mouse cortex, hemodynamics parameters, including pressure, flow, vessel diameter-adjustable hematocrit, and transit time are calculated as a function of stalling events.
Int J Mol Sci
January 2024
Institute of Translational Medicine, Semmelweis University, 1094 Budapest, Hungary.
Carotid artery stenosis (CAS) affects approximately 5-7.5% of older adults and is recognized as a significant risk factor for vascular cognitive impairment (VCI). The impact of CAS on cerebral blood flow (CBF) within the ipsilateral hemisphere relies on the adaptive capabilities of the cerebral microcirculation.
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