Abstract
Angiogenesis is a hallmark of many conditions, including cancer, stroke, vascular disease, diabetes, and high-altitude exposure. We have previously shown that one can study angiogenesis in animal models by using total hemoglobin (tHb) as a marker of cerebral blood volume (CBV), measured using broadband near-infrared spectroscopy (bNIRS). However, the method was not suitable for patients as global anoxia was used for the calibration. Here we determine if angiogenesis could be detected using a calibration method that could be applied to patients. CBV, as a marker of angiogenesis, is quantified in a rat cortex before and after hypoxia acclimation. Rats are acclimated at 370-mmHg pressure for three weeks, while rats in the control group are housed under the same conditions, but under normal pressure. CBV increased in each animal in the acclimation group. The mean CBV (%volume/volume) is 3.49%± 0.43% (mean ± SD) before acclimation for the experimental group, and 4.76%± 0.29% after acclimation. The CBV for the control group is 3.28%± 0.75%, and 3.09%± 0.48% for the two measurements. This demonstrates that angiogenesis can be monitored noninvasively over time using a bNIRS system with a calibration method that is compatible with human use and less stressful for studies using animals.
Highlights
Noninvasive measurements of cerebral blood volume (CBV) can be used as a marker of vascular density.[1,2] By quantifying vascular density, one can study the process of angiogenesis, or growing new blood vessels, which is a significant area of interest in the study of diseases such as cancer, stroke, and diabetes.[3,4,5]
We showed previously that quantitative near-infrared spectroscopy via a broadband NIRS system can be used to quantify tissue total hemoglobin ([tHb]) and CBV as a method of monitoring angiogenesis in rat brain.[1] broadband near-infrared spectroscopy (bNIRS) measures a broad near-infrared (NIR) spectrum and uses modeling of the attenuation spectra to measure tissue deoxyhemoglobin concentrations.[1,11]
We show that quantifying angiogenesis in brain in a repeated, noninvasive fashion is possible with bNIRS using a graded hypoxia calibration method
Summary
Noninvasive measurements of cerebral blood volume (CBV) can be used as a marker of vascular density.[1,2] By quantifying vascular density, one can study the process of angiogenesis, or growing new blood vessels, which is a significant area of interest in the study of diseases such as cancer, stroke, and diabetes.[3,4,5]
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