Capillary network formation and structure in a modified discrete mathematical model of angiogenesis

Angiogenesis, as part of cancer development, involves hierarchical complicated events and processes. Multiple studies have revealed the significance of the formation and structure of tumor-induced capillary networks. In this study, a discrete mathematical model of angiogenesis is studied and modified to capture the realistic physics of capillary network formation. Modifications are performed on the mathematical foundations of an existing discrete model of angiogenesis. The main modifications are the imposition of the matrix density effect, implementation of realistic boundary and initial conditions, and improvement of the method of governing equations based on physical observation. Results show that endothelial cells accelerate angiogenesis and capillary formation as they migrate toward the tumor and clearly exhibit the physical concept of haptotactic movement. On the other hand, consideration of blood flow-induced stress leads to a dynamic adaptive vascular network of capillaries which intelligibly reflects the brush border effect . The present modified model of capillary network formation is based on the physical rationale that defines a clear mathematical and physical interpretation of angiogenesis, which is likely to be used in cancer development modeling and anti-angiogenic therapies.

Peripapillary capillary network in dominant optic atrophy linked to OPA1 gene

Peripapillary capillary network using optical coherence tomography angiography (OCT-A) was analysed in two siblings suffering from dominant optic atrophy linked to OPA-1 gene mutation. Peripapillary capillary network has been scarcely described in this type of optic atrophy.

Pathomorphological manifestations of vascular remodeling in the perifocal areas of ischemic cerebral infarction

Acute disorders of cerebral circulation remain one of the leading causes of death of patients throughout the world. Tissue recovery after a stroke is directly related to active revascularization, which is intensified in the peri-infarction area. Newly formed vessels contribute to the restoration of cellular metabolism in surviving neurons. The processes of vascular remodeling after stroke have been at the center of many clinical and morphological studies in recent years. The aim of the study. To study the processes of vascular remodeling and neoplasm of vessels in the perifocal areas of ischemic cerebral infarctions. Material and methods. The study researched the brain of 29 deceased patients with hemispheric infarctions with different periods of the disease: up to 3 days (n = 5), 6 days (n = 5), 9-12 (n = 10), 30 (n = 5), 45 days (n = 4). The object of the study was perifocal areas of cerebral infarction, as well as areas outside ischemic lesions. The studies were carried out using histological, morphometric and statistical techniques. Results. Studies have shown that in the perifocal areas of cerebral infarction within 3 days from the onset of the disease, the morpho-functional state of the microvasculature was characterized by circulatory and hemocoagulation disorders. Along with destructive changes in blood vessels, processes are directed to improve blood circulation in ischemic areas of the brain. Collateral blood flow increases, dilation of pial vessels is noted with a decrease in the Kernogan index. On the 6th day, the processes of angiogenesis and vasculogenesis are activated, which intensify in the subsequent stages of the disease. In the long term, the efficiency of collateral blood flow in the pial vessels decreases, reduction in the capillary network, and the lumen of large arteries is recalibrated. Conclusions. In the early stages of cerebral stroke (up to 3 days), increased blood circulation in the ischemic areas of the brain occurs due to increased collateral blood flow. From the 6th day, the processes of angiogenesis in the form of capillary budding and the processes of vasculogenesis intensify. In large arterioles, recalibration processes take place. After 30-45 days in the perifocal areas of cerebral infarction, a significant reduction of the capillary network is recorded, which is regarded as a reaction to a decrease in blood supply to the areas of organized infarction.

Pericytes: Intrinsic Transportation Engineers of the CNS Microcirculation

Pericytes in the brain are candidate regulators of microcirculatory blood flow because they are strategically positioned along the microvasculature, contain contractile proteins, respond rapidly to neuronal activation, and synchronize microvascular dynamics and neurovascular coupling within the capillary network. Analyses of mice with defects in pericyte generation demonstrate that pericytes are necessary for the formation of the blood-brain barrier, development of the glymphatic system, immune homeostasis, and white matter function. The development, identity, specialization, and progeny of different subtypes of pericytes, however, remain unclear. Pericytes perform brain-wide ‘transportation engineering’ functions in the capillary network, instructing, integrating, and coordinating signals within the cellular communicome in the neurovascular unit to efficiently distribute oxygen and nutrients (‘goods and services’) throughout the microvasculature (‘transportation grid’). In this review, we identify emerging challenges in pericyte biology and shed light on potential pericyte-targeted therapeutic strategies.