Platelet-Derived Growth Factor and Spatiotemporal Cues Induce Development of Vascularized Bone Tissue by Adipose-Derived Stem Cells

Hutton, Daphne L.; Moore, Erika; Gimble, Jeffrey M.; Grayson, Warren L.

doi:10.1089/ten.tea.2012.0752

Cited by 55 publications

(63 citation statements)

References 64 publications

(75 reference statements)

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“…As a result, current tissue engineering efforts focus on developing synthetic bone grafts with preformed, functional vascular networks (124)(125). Before implantation, mineral deposition in these grafts is spatially associated with the vascular network, consistent with the hypothesis that vascularized bone grafts improve subsequent bone formation (126). Improvements in this important area of regenerative medicine will rely on previous research of bone blood flow, as researchers hunt for the right combination of scaffold, cell source, and growth factors.…”

Section: Blood Flow In Bone Graftsmentioning

confidence: 91%

Skeletal Blood Flow in Bone Repair and Maintenance

2013

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Bone is a highly vascularized tissue, although this aspect of bone is often overlooked. In this article, the importance of blood flow in bone repair and regeneration will be reviewed. First, the skeletal vascular anatomy, with an emphasis on long bones, the distinct mechanisms for vascularizing bone tissue, and methods for remodeling existing vasculature are discussed. Next, techniques for quantifying bone blood flow are briefly summarized. Finally, the body of experimental work that demonstrates the role of bone blood flow in fracture healing, distraction osteogenesis, osteoporosis, disuse osteopenia, and bone grafting is examined. These results illustrate that adequate bone blood flow is an important clinical consideration, particularly during bone regeneration and in at-risk patient groups. IntroductionThe rate at which blood vessels deliver oxygen, nutrients, growth factors, and circulating cells to boneis tightly regulated as a function of blood pressure and vascularizaAll biological tissues, including bone, require vascular support to survive. However, a frequently overlooked feature of bone is its extensive vascular network. Many studies have demonstrated that the blood vessels in bone are necessary for nearly all skeletal functions, including development, homeostasis, and repair (1). In addition, blood vessels lost due to trauma are regenerated, and new bone tissue formed in response to injury is vascularized. As a consequence of this environment, the blood vessels in bone are highly active, not simply a passive source for the delivery of nutrients (2). Readers are referred to recent publications for more information about the active processes of the vasculature not covered in this review, including the vascular niche and hypoxia-driven signaling pathways (3-4). tion. Given that blood pressure is generally maintained, the number and size of blood vessels determines the local blood flow rate. These two factors are regulated through the processes of angiogenesis and vasomotor function, respectively. Although a variety of skeletal disorders are associated with general vascular dysfunction (5-7), this review will focus on the regulation of bone blood flow, through the number and size of vessels, during bone repair and regeneration. To introduce this topic, the skeletal vascular anatomy and techniques for measuring bone blood flow are briefly discussed. Blood supply in boneA dense vascular network delivers oxygen and nutrients to all 206 bones in the human body. In general, this requires a substantial portion of the total cardiac output. Experimental work in various animal species has demonstrated that a significant portion of the resting cardiac output is directed to the skeleton, likely between 10% and 15% (8-12).For some time, the blood flow pattern in bones has been described as primarily centrifugal: blood is supplied to the cortical bone through the nutrient arteries in the (Figure 1), and returned by the periosteal veins (13). Particularly in long bones, the vascular anatomy is well characterized, wi...

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Section: Blood Flow In Bone Graftsmentioning

confidence: 91%

Skeletal Blood Flow in Bone Repair and Maintenance

2013

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“…This involves cells spontaneously aggregating at the bottom of a drop after inverting a plate with drops of cell suspension. 24 Briefly, after in vitro expansion, the cells were trypsinized and resuspended at a concentration of 400,000 cells/mL 24 in the basal medium containing 0.24% (w/v) methylcellulose (Sigma-Aldrich, St. Louis, MO). This cell suspension was then pipetted onto an inverted culture dish cover with 10 mL per droplet using a multichannel pipette.…”

Section: Cell Culturementioning

confidence: 99%

Physiologically Low Oxygen Enhances Biomolecule Production and Stemness of Mesenchymal Stem Cell Spheroids

Shearier

Xing

Qian

et al. 2016

Tissue Engineering Part C: Methods

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Multicellular human mesenchymal stem cell (hMSC) spheroids have been demonstrated to be valuable in a variety of applications, including cartilage regeneration, wound healing, and neoangiogenesis. Physiological relevant low oxygen culture can significantly improve in vitro hMSC expansion by preventing cell differentiation. We hypothesize that hypoxia-cultured hMSC spheroids can better maintain the regenerative properties of hMSCs. In this study, hMSC spheroids were fabricated using hanging drop method and cultured under 2% O 2 and 20% O 2 for up to 96 h. Spheroid diameter and viability were examined, as well as extracellular matrix (ECM) components and growth factor levels between the two oxygen tensions at different time points. Stemness was measured among the spheroid culture conditions and compared to two-dimensional cell cultures. Spheroid viability and structural integrity were studied using different needle gauges to ensure no damage would occur when implemented in vivo. Spheroid attachment and integration within a tissue substitute were also demonstrated. The results showed that a three-dimensional hMSC spheroid cultured at low oxygen conditions can enhance the production of ECM proteins and growth factors, while maintaining the spheroids' stemness and ability to be injected, attached, and potentially be integrated within a tissue.

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“…12 Briefly, samples were fixed with 3.7% formaldehyde for 3 h at 4°C, washed with PBS, and blocked with 5% normal goat serum/0.2% Triton X-100/PBS for 3 h at 4°C. Antibodies were incubated overnight at 4°C, followed by three 1-h washes in PBS with 0.1% Tween.…”

Section: Whole-mount Immunostainingmentioning

confidence: 99%

“…9,10 Our group has previously demonstrated that early passage ASCs are inherently heterogeneous, containing a residual subpopulation of endothelial progenitors that can proliferate extensively to grow into densely interconnected vascular networks. 11,12 This self-assembly is driven by heterotypic physical and biochemical cell signaling with neighboring ASCs 11 and is substantially improved following cell aggregation. 12 This heterogeneous self-assembling nature of ASCs makes them an attractive cell source for tissue engineering strategies that require stem cell differentiation or trophic signaling combined with vascular support.…”

mentioning

confidence: 99%

“…11,12 This self-assembly is driven by heterotypic physical and biochemical cell signaling with neighboring ASCs 11 and is substantially improved following cell aggregation. 12 This heterogeneous self-assembling nature of ASCs makes them an attractive cell source for tissue engineering strategies that require stem cell differentiation or trophic signaling combined with vascular support.…”

mentioning

confidence: 99%

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Hypoxia Inhibits De Novo Vascular Assembly of Adipose-Derived Stromal/Stem Cell Populations, but Promotes Growth of Preformed Vessels

Hutton

Grayson

2016

Tissue Engineering Part A

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Vascularization is critical for cell survival within tissue-engineered grafts. Adipose-derived stromal/stem cells (ASCs) are widely used in tissue engineering applications as they are a clinically relevant source of stem cells and endothelial progenitor cells. ASCs have previously been shown to self-assemble into pericyte-stabilized vascular networks in normoxic (20% O 2 ) cultures. This capacity for de novo vascular assembly may accelerate graft vascularization in vivo rather than relying solely on angiogenic ingrowth. However, oxygen depletion within large cell-seeded grafts will be rapid, and it is unclear how this worsening hypoxic environment will impact the vascular assembly of the transplanted cells. The objectives of this study were to determine whether ASC-derived vessels could grow in hypoxia and to assess whether the vessel maturity (i.e., individual cells vs. preformed vessels) influenced this hypoxic response. Utilizing an in vitro vascularization model, ASCs were encapsulated within fibrin gels and cultured in vitro for up to 6 days in either normoxia (20% O 2 ) or hypoxia (0.2% or 2% O 2 ). In a subsequent experiment, vessels were allowed to preform in normoxia for 6 days before an additional 6 days of either normoxia or hypoxia. Viability, vessel growth, pericyte coverage, proliferation, metabolism, and angiogenic factor expression were assessed for each experimental approach. Vessel growth was dramatically inhibited in both moderate and severe hypoxia (47% and 11% total vessel length vs. normoxia, respectively), despite maintaining high cell viability and upregulating endogenous expression of vascular endothelial growth factor in hypoxia. Bromodeoxyuridine labeling indicated significantly reduced proliferation of endothelial cells in hypoxia. In contrast, when vascular networks were allowed to preform for 6 days in normoxia, vessels not only survived but also continued to grow more in hypoxia than those maintained in normoxia. These findings demonstrate that vascular assembly and growth are tightly regulated by oxygen tension and may be differentially affected by hypoxic conditions based on the maturity of the vessels. Understanding this relationship is critical to developing effective approaches to engineer viable tissue-engineered grafts in vivo.

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Platelet-Derived Growth Factor and Spatiotemporal Cues Induce Development of Vascularized Bone Tissue by Adipose-Derived Stem Cells

Cited by 55 publications

References 64 publications

Skeletal Blood Flow in Bone Repair and Maintenance

Skeletal Blood Flow in Bone Repair and Maintenance

Physiologically Low Oxygen Enhances Biomolecule Production and Stemness of Mesenchymal Stem Cell Spheroids

Hypoxia Inhibits De Novo Vascular Assembly of Adipose-Derived Stromal/Stem Cell Populations, but Promotes Growth of Preformed Vessels

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