Microvascular development in the rat arteriovenous loop model in vivo—A step by step intravital microscopy analysis

Abstract

The arteriovenous (AV) loop model is a key technique to solve one of the major problems of tissue engineering-providing adequate vascular support for a tissue construct of significant size. However, the molecular and cellular mechanisms of vascularization and factors influencing the generation of new tissue in the AV loop are still poorly understood. We previously established a novel intravital microscopy approach to study these events. In this study, we implanted our observation chamber filled with two types of hydrogels such as fibrin and methacrylate gelatin (GelMA) and performed intravital microscopy (IVM) on days 7, 14, and 21. Initial microvessel formation was observed in GelMA on day 14, while the vessel network showed clear indicators of network rearrangement and maturation on day 21. No visible microvessels were observed in fibrin. The chambers were explanted on day 21.Histological examination revealed higher numbers of microvessels in GelMA compared to fibrin, while the AV loop was thrombosed in all fibrin constructs, possibly due to matrix degradation. GelMA proved to be an ideal matrix for IVM studies in the AV loop model due to its slow degradation and transparency. This IVM model can be employed as a novel tool for live and thus faster comprehension of crucial events in the tissue regeneration process, which can improve tissue engineering application.

<i>In vivo</i> application of prevascularized bone scaffolds: A literature review

“…[19], к тому же в петле с применением фибрина образовались тромбы, что R. Vaghela и соавт. [30] связали с резорбцией фибринового скаффолда.…”

A Novel Window into Angiogenesis—Intravital Microscopy in the AV-Loop-Model

“…Neovessel outgrowth from the AV loop was analyzed as described previously [18,19]. Briefly, overlaid vessel network sketches for each High-Power Field (HPF) were prepared using the GNU Image Manipulation Program (GIMP).…”

“…This manuscript summarizes our efforts to establish IVM in the AV loop and evaluate its value for assessing vascular development in the AV loop. We have developed several different chamber designs [18,19]. Chamber design A allows repeated short-term (direct) imaging of the initial dynamic event following AV loop surgery, while chamber design B enables periodic longitudinal assessment of the vascularization and de novo tissue generation.…”

An In Vitro Approach for Investigating the Safety of Lipotransfer after Breast-Conserving Therapy

“…Whereas predominantly clinical studies claim a safe use of lipotransfer [ 13 , 14 , 15 , 16 , 17 , 18 ], pre-clinical studies suggested an ADSC-induced promotion of breast cancer growth and tumor angiogenesis [ 9 , 19 , 20 , 21 , 22 ]. Among other factors, the role of vascularization in any recipient tissue for cell ingrowth or proliferation is certainly relevant [ 23 , 24 , 25 ]. Further, previous studies showed that ADSC can also influence healthy breast tissue and induce an epithelial-to-mesenchymal transition in mammary epithelial cells [ 26 ].…”