VasoMetrics: unbiased spatiotemporal analysis of microvascular diameter in multi-photon imaging applications

McDowell, Konnor; Berthiaume, Andrée-Anne; Tieu, Taryn; Hartmann, David A.; Shih, Andy Y.

doi:10.21037/qims-20-920

Cited by 54 publications

(49 citation statements)

References 31 publications

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“…to the experimental group. To reduce bias of measurement location, we used a custom ImageJ/Fiji macro called VasoMetrics 73 to analyze lumen diameter at multiple, equidistant locations along each vessel segment of interest. The user first draws a line that bisects the vessel segment to be measured.…”

Section: Methodsmentioning

confidence: 99%

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Brain capillary pericytes exert a substantial but slow influence on blood flow

et al. 2021

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The majority of the brain’s vasculature is comprised of intricate capillary networks lined by capillary pericytes. However, it remains unclear whether capillary pericytes influence blood flow. Using two-photon microscopy to observe and manipulate brain capillary pericytes in vivo , we find that their optogenetic stimulation decreases lumen diameter and blood flow, but with slower kinetics than similar stimulation of mural cells on upstream pial and pre-capillary arterioles. This slow vasoconstriction was inhibited by the clinically-used vasodilator fasudil, a Rho-kinase inhibitor that blocks contractile machinery. Capillary pericytes were also slower to constrict back to baseline following hypercapnia-induced dilation, and slower to dilate towards baseline following optogenetically-induced vasoconstriction. Optical ablation of single capillary pericytes led to sustained local dilation and a doubling of blood cell flux selectively in capillaries lacking pericyte contact. These data indicate that capillary pericytes contribute to basal blood flow resistance and slow modulation of blood flow throughout the brain.

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Section: Methodsmentioning

confidence: 99%

“…Vasometrics 73 , an ImageJ/Fiji-based macro for unbiased vessel diameter measurement, can be downloaded at: https://github.com/mcdowellkonnor/ResearchMacros . All other code is available from the corresponding author upon request.…”

Section: Methodsmentioning

confidence: 99%

Brain capillary pericytes exert a substantial but slow influence on blood flow

et al. 2021

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“…For analysis of blood cell velocity from line-scan data, we used custom Matlab software from Kim et al (55). Lumen diameter for penetrating arterioles and ascending venules was calculated using and ImageJ-based macro called VasoMetrics (56). Blood cell velocity and vessel diameter were then combined using a formula based on Poiseuille's law of laminar flow to obtain the volume flux of blood flow, which is a more complete metric of flow through a single vessel (39).…”

Section: Methodsmentioning

confidence: 99%

Imaging the construction of capillary networks in the neonatal mouse brain

Coelho-Santos

Berthiaume

Ornelas

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Capillary networks are essential for distribution of blood flow through the brain, and numerous other homeostatic functions, including neurovascular signal conduction and blood–brain barrier integrity. Accordingly, the impairment of capillary architecture and function lies at the root of many brain diseases. Visualizing how brain capillary networks develop in vivo can reveal innate programs for cerebrovascular growth and repair. Here, we use longitudinal two-photon imaging through noninvasive thinned skull windows to study a burst of angiogenic activity during cerebrovascular development in mouse neonates. We find that angiogenesis leading to the formation of capillary networks originated exclusively from cortical ascending venules. Two angiogenic sprouting activities were observed: 1) early, long-range sprouts that directly connected venules to upstream arteriolar input, establishing the backbone of the capillary bed, and 2) short-range sprouts that contributed to expansion of anastomotic connectivity within the capillary bed. All nascent sprouts were prefabricated with an intact endothelial lumen and pericyte coverage, ensuring their immediate perfusion and stability upon connection to their target vessels. The bulk of this capillary expansion spanned only 2 to 3 d and contributed to an increase of blood flow during a critical period in cortical development.

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“…These vessel diameter measurements accounted for the lumen of the vessel, at half of the maximum fluorescence intensity profile and were adjusted for pixelation of 2PLSM data. These measurements have been further refined through VasoMetrics ImageJ macro (McDowell et al, 2021). To identify the radii and diameter measurements from the STPT imaging data, exact vessel coordinates were used to retrieve the associated vessel radii measurements using custom MATLAB code.…”

Section: In Vivo and Ex Vivo Comparisonmentioning

confidence: 99%

The cellular architecture of microvessels, pericytes and neuronal cell types in organizing regional brain energy homeostasis in mice

Chon

et al. 2021

Preprint

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The cerebrovascular network and its mural cells must meet the dynamic energy demands of different neuronal cell types across the brain, but their spatial relationship among these cells is largely unknown. Here, we apply brain-wide mapping methods to create a comprehensive cellular-resolution resource comprising the distribution of and quantitative relationship between microvessels, pericytes, and glutamatergic and GABAergic neurons including neuronal nitric oxide synthase-positive (nNOS+) neurons and their subtypes in mice. Leveraging these data, we discovered region-specific signatures of vasculature and cell type compositions across cortical and subcortical areas, including strikingly contrasting correlations between the density of vasculature, pericytes, glutamatergic neurons and parvalbumin-positive interneurons versus nNOS+ neurons in the isocortex. We also found surprisingly low vasculature and pericyte density in the hippocampus, and distinctly high pericyte to vasculature ratio in the hypothalamus. These findings suggest that vascular density and mural cell composition is finely tuned to maintain regional energy homeostasis.

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VasoMetrics: unbiased spatiotemporal analysis of microvascular diameter in multi-photon imaging applications

Cited by 54 publications

References 31 publications

Brain capillary pericytes exert a substantial but slow influence on blood flow

Brain capillary pericytes exert a substantial but slow influence on blood flow

Imaging the construction of capillary networks in the neonatal mouse brain

The cellular architecture of microvessels, pericytes and neuronal cell types in organizing regional brain energy homeostasis in mice

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