Vessel grafts for tissue engineering revisited—Vessel segments show location‐specific vascularization patterns in ex vivo ring assay

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.

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“…Microcirculatory analysis was performed as described previously 13,17 . Intravital images were taken from each region of interest (ROI).…”

Section: Methodsmentioning

confidence: 99%

“…Microcirculatory analysis was performed as described previously. 13,17 Intravital images were taken from each region of interest (ROI). The entire tissue area showing any signs of microvascular sprouting was covered in each imaging session.…”

Section: Microcirculatory Analysismentioning

confidence: 99%

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

Vaghela

Arkudas

Gage

et al. 2022

J Biomedical Materials Res

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“…For the latter ones, a high degree of surgical expertise is necessary and therefore requires the treatment in an experienced center. Tissue engineering, especially generation of skin substitutes as well as later methods of regenerative medicine to replace the lost soft or hard tissue and/or skin is a promising new tool in this context (28)(29)(30)(31)(32).…”

Section: Discussionmentioning

confidence: 99%

“…Tissue engineering, especially generation of skin substitutes as well as later methods of regenerative medicine to replace the lost soft or hard tissue and/or skin is a promising new tool in this context ( 28 – 32 ).…”

Section: Discussionmentioning

confidence: 99%

The Value of Negative-Pressure Wound Therapy and Flap Surgery in Hidradenitis Suppurativa – A Single Center Analysis of Different Treatment Options

et al. 2022

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BackgroundHidradenitis suppurativa is manifested by painful abscesses and scarring of sweat glands. Axillary, inguinal and genital regions are mostly affected. Multiple options exist in the treatment of hidradenitis suppurativa. The aim of this retrospective, mono-center cohort study was to analyze the outcome of different treatment methods after radical excision of hidradenitis suppurativa.MethodsWe retrospectively evaluated the treatment strategy and recurrence rate of hidradenitis suppurativa. We included all eligible patients of legal age between February 2003 and October 2021, with the diagnosis of Hidradenitis suppurativa and the necessity for surgical treatment. All patients with surgical treatment and direct wound closure by suture were excluded. Bacterial load and flora were analyzed for primary and secondary reconstruction in combination with negative-pressure wound therapy. Patient data were analyzed for recurrence rate and remission time according to different reconstructive techniques.ResultsIn 44 affected anatomical sites (n = 23 patients) we treated 15 patients with negative-pressure wound therapy. Bacterial load and flora were lower in the last wound swab of patients with multi-surgical procedures (22 localizations) compared to the first wound swab independent of the use of negative-pressure wound therapy.Wound closure, independent of a direct and multi-stage procedure was achieved by local fasciocutaneous flaps (n = 12), secondary intention healing (n = 7), secondary intention healing with buried chip skin grafts (n = 10), or split-thickness skin grafts (n = 15). Radical excision combined with split-thickness skin grafts showed the lowest recurrence rate in the follow-up (16%; n = 4).ConclusionRadical excision of hidradenitis suppurativa as gold standard for surgical treatment combined with negative-pressure wound therapy as multi-stage procedures ultimately reduced bacterial load and flora in our study. The use of split-thickness skin grafts showed the lowest recurrence rate.

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“…These assays have primarily been used to study angiogenesis in a more complex, physiologic model in contrast to simplistic in vitro models that may not replicate the complexity of multiple cell types, growth factors, and extracellular matrix present in vivo. One study investigated sprouting from vessels isolated from different regions throughout the body and compared sprouting from arteries and veins 27 . Though these models do result in a multiscale construct consisting of an artery segment and sprouted capillaries, sprouting typically occurs from the lumenal end of the artery, which would diminish their capability to be sutured into circulation and used in a therapeutic application.…”

Section: Introductionmentioning

confidence: 99%

Engineering primitive multiscale chimeric vasculature by combining human microvessels with explanted murine vessels

Margolis,

Choi,

Friend

et al. 2024

Sci Rep

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Strategies to separately manufacture arterial-scale tissue engineered vascular grafts and microvascular networks have been well-established, but efforts to bridge these two length scales to create hierarchical vasculature capable of supporting parenchymal cell functions or restoring perfusion to ischemic tissues have been limited. This work aimed to create multiscale vascular constructs by assessing the capability of macroscopic vessels isolated from mice to form functional connections to engineered capillary networks ex vivo. Vessels of venous and arterial origins from both thoracic and femoral locations were isolated from mice, and then evaluated for their abilities to sprout endothelial cells (EC) capable of inosculating with surrounding human cell-derived microvasculature within bulk fibrin hydrogels. Comparing aortae, vena cavae, and femoral vessel bundles, we identified the thoracic aorta as the rodent macrovessel that yielded the greatest degree of sprouting and interconnection to surrounding capillaries. The presence of cells undergoing vascular morphogenesis in the surrounding hydrogel attenuated EC sprouting from the macrovessel compared to sprouting into acellular hydrogels, but ultimately sprouted mouse EC interacted with human cell-derived capillary networks in the bulk, yielding chimeric vessels. We then integrated micromolded mesovessels into the constructs to engineer a primitive 3-scale vascular hierarchy comprising capillaries, mesovessels, and macrovessels. Overall, this study yielded a primitive hierarchical vasculature suitable as proof-of-concept for regenerative medicine applications and as an experimental model to better understand the spontaneous formation of host-graft vessel anastomoses.

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Vessel grafts for tissue engineering revisited—Vessel segments show location‐specific vascularization patterns in ex vivo ring assay

Cited by 3 publications

References 28 publications

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

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

The Value of Negative-Pressure Wound Therapy and Flap Surgery in Hidradenitis Suppurativa – A Single Center Analysis of Different Treatment Options

Engineering primitive multiscale chimeric vasculature by combining human microvessels with explanted murine vessels

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