Chronic exposure to a hypoxic environment leads to structural and functional adaptations in the rat brain. One significant adaptation is a decrease in intercapillary distances through a near doubling of the capillary density, which begins after about 1 week of hypoxic exposure and is completed by 3 weeks. Hypoxic angiogenesis is controlled by activation of downstream genes by Hypoxia Inducible Factor-1 and Angiopoietin-2. The processes that increase capillary density are reversible upon restoration of the ambient oxygen concentration. Capillary regression, which also occurs over a 3-week period, is accomplished through activation of apoptosis. The implication from these observations is that the brain naturally functions in a low, but controlled, oxygen environment. Acute imbalances in oxygen delivery and metabolic demand are addressed through changes in blood flow; persistent imbalances activate mechanisms that adjust capillary density. The mechanisms that control these processes decline with age.
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http://dx.doi.org/10.1242/jeb.00976 | DOI Listing |
Materials (Basel)
December 2024
Department of Material Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
This manuscript contributes to understanding the role of hydrogen in different materials, emphasizing polymers and composite materials, to increase hydrogen storage capacity in those materials. Hydrogen storage is critical in advancing and optimizing sustainable energy solutions that are essential for improving their performance. Capillary arrays, which offer increased surface area and optimized storage geometries, present a promising avenue for enhancing hydrogen uptake.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Dipartimento di Biotecnologie e Scienze della Vita, ASST Sette Laghi, Università degli Studi dell'Insubria, 21100 Varese, Italy.
Hypertension exerts a profound impact on the microcirculation, causing both structural and functional alterations that contribute to systemic and organ-specific vascular damage. The microcirculation, comprising arterioles, capillaries, and venules with diameters smaller than 20 μm, plays a fundamental role in oxygen delivery, nutrient exchange, and maintaining tissue homeostasis. In the context of hypertension, microvascular remodeling and rarefaction result in reduced vessel density and elasticity, increasing vascular resistance and driving end-organ damage.
View Article and Find Full Text PDFJ Clin Med
December 2024
Physio-Pathology and Immunology Department, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania.
: With the development of artificial intelligence (A.I.), the optical coherence tomography angiography (OCTA) analysis of progression in hypertensive retinopathy could be improved.
View Article and Find Full Text PDFObesity is a global health crisis, with its prevalence particularly severe in the United States, where over 42% of adults are classified as obese. Obesity is driven by complex molecular and tissue-level mechanisms that remain poorly understood. Among these, angiogenesis-primarily mediated by vascular endothelial growth factor (VEGF-A)-is critical for adipose tissue expansion but presents unique challenges for therapeutic targeting due to its intricate regulation.
View Article and Find Full Text PDFRetina
January 2025
Neuroradiology Department, CHRU Gui de Chauliac, F-34091 Montpellier, France.
Purpose: To investigate retinal microvascular changes in ischemic stroke patients using optical coherence tomography angiography (OCT-A) and assess these alterations based on stroke etiology.
Methods: Case-control study conducted at Montpellier University Hospital from May 2021 to March 2022 (IRB: 202000607). Retinal vascular features were compared between strokes patients and age- and sex- matched controls.
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