tissue-engineering-intrinsic-vascularization-an-vivo-tissue

Tissue Engineering by Intrinsic Vascularization in an <em>In Vivo</em> Tissue Engineering Chamber

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and ...

St Vincent's Institute of Medical Research

Tissue engineering chamber (TEC) makes it possible to generate significant amounts of mature, vascularized, stable, and transferable adipose tissue. However, little is known about the role of the chamber in tissue engineering. Therefore, to investigate the role of inflammatory response and the change in mechanotransduction started by TEC after implantation, we placed a unique TEC model on the surface of the groin fat pads in rats to study the expression of cytokines and tissue development in the TEC. The number of infiltrating cells was counted, and vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) expression levels in the chamber at multiple time points postimplantation were analyzed by enzyme-linked immunosorbent assay. Tissue samples were collected at various time points and labeled for specific cell populations. The result showed that new adipose tissue formed in the chamber at day 60. Also, the expression of MCP-1 and VEGF in the chamber decreased slightly from an early stage as well as the number of the infiltrating cells. A large number of CD34+/perilipin- perivascular cells could be detected at day 30. Also, the CD34+/perilipin+ adipose precursor cell numbers increased sharply by day 45 and then decreased by day 60. CD34-/perilipin+ mature adipocytes were hard to detect in the chamber content at day 30, but their number increased and then peaked at day 60. Ki67-positive cells could be found near blood vessels and their number decreased sharply over time. Masson's trichrome showed that collagen was the dominant component of the chamber content at early stage and was replaced by newly formed small adipocytes over time. Our findings suggested that the TEC implantation could promote the proliferation of adipose precursor cells derived from local adipose tissue, increase angiogenesis, and finally lead to spontaneous adipogenesis by inducing aseptic inflammation and changing local mechanotransduction.

Tissue engineering chamber promotes adipose tissue regeneration in adipose tissue engineering models through induced aseptic inflammation.

To evaluate the mechanism of stromal vascular fraction (SVF) promoting angiogenesis and tissue regeneration in tissue engineering chamber.

[Preliminary study on stromal vascular fraction promoting angiogenesis and tissue regeneration in tissue engineering chamber].

The major drawback of adipose grafting is its clinical unpredictability, which leads to surgeon and patient dissatisfaction. The mechanisms underlying angiogenesis and regeneration of the graft tissue are still unclear.

The angiogenic and adipogenic modes of adipose tissue after free fat grafting.

The development of an engineered adipose tissue substitute capable of supporting reliable, predictable, and complete fat tissue regeneration would be of value in plastic and reconstructive surgery. For adipogenesis, a tissue engineering chamber provides an optimized microenvironment that is both efficacious and reproducible; however, for reasons that remain unclear, tissues regenerated in a tissue engineering chamber consist mostly of connective rather than adipose tissue. Here, we describe a chamber-based system for improving the yield of mature adipose tissue and discuss the potential mechanism of adipogenesis in tissue-chamber models. Adipose tissue flaps with independent vascular pedicles placed in chambers were implanted into rabbits. Adipose volume increased significantly during the observation period (week 1, 2, 3, 4, 16). Histomorphometry revealed mature adipose tissue with signs of adipose tissue remolding. The induced engineered constructs showed high-level expression of adipogenic (peroxisome proliferator-activated receptor γ), chemotactic (stromal cell-derived factor 1a), and inflammatory (interleukin 1 and 6) genes. In our system, the extracellular matrix may have served as a scaffold for cell migration and proliferation, allowing mature adipose tissue to be obtained in a chamber microenvironment without the need for an exogenous scaffold. Our results provide new insights into key elements involved in the early development of adipose tissue regeneration.

Self-synthesized extracellular matrix contributes to mature adipose tissue regeneration in a tissue engineering chamber.

By observing the adipogenic and angiogenic microenvironment impact on the morphology of newly generated tissue for exploring the key factors which inducing mature adipose tissue regeneration in tissue engineering model.

[The impact of angiogenic and adipogenic microenvironment on adipose tissue regeneration in tissue engineering chamber].

In reconstructive surgery, there is a clinical need for adequate implants to repair soft tissue defects caused by traumatic injury, tumor resection, or congenital abnormalities. Adipose tissue engineering may provide answers to this increasing demand. This study comprehensively reviews current approaches to adipose tissue engineering, detailing different cell carriers under investigation, with a special focus on the application of adipose-derived stem cells (ASCs). ASCs act as building blocks for new tissue growth and as modulators of the host response. Recent studies have also demonstrated that the implantation of a hollow protected chamber, combined with a vascular pedicle within the fat flaps provides blood supply and enables the growth of large-volume of engineered soft tissue. Conceptually, it would be of value to co-regulate this unique chamber model with adipose-derived stem cells to obtain a greater volume of soft tissue constructs for clinical use. Our review provides a cogent update on these advances and details the generation of possible fat substitutes.

Article	Year
Tissue engineering chamber promotes adipose tissue regeneration in adipose tissue engineering models through induced aseptic inflammation. Tissue engineering. Part C, Methods\| PubMed ID: 24559078	2014
[Preliminary study on stromal vascular fraction promoting angiogenesis and tissue regeneration in tissue engineering chamber]. Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery\| PubMed ID: 25073289	2014
The angiogenic and adipogenic modes of adipose tissue after free fat grafting. Plastic and reconstructive surgery\| PubMed ID: 25719720	2015
Self-synthesized extracellular matrix contributes to mature adipose tissue regeneration in a tissue engineering chamber. Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society\| PubMed ID: 25847278	2015
[The impact of angiogenic and adipogenic microenvironment on adipose tissue regeneration in tissue engineering chamber]. Zhonghua zheng xing wai ke za zhi = Zhonghua zhengxing waike zazhi = Chinese journal of plastic surgery\| PubMed ID: 25895300	2014
Adipose-Derived Stem Cell Delivery for Adipose Tissue Engineering: Current Status and Potential Applications in a Tissue Engineering Chamber Model. Stem cell reviews\| PubMed ID: 27075632	2016

Weiqing Zhan

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