3D Bioplotter Research Papers

Displaying all papers by F. Tavassol (12 results)

Angiogenic effects of mesenchymal stem cells in combination with different scaffold materials

Microvascular Research 2019

Tissue survival in regenerative tissue engineering requires rapid vascularization, which is influenced by scaffold material and seeded cell selection. Poly-l-lactide-co-glycolide (PLGA) and beta-tricalcium phosphate (β-TCP) are well-established biomaterials with angiogenic effects because of their material properties. Given the importance of the seeded cell type as a co-factor for vascularization, mesenchymal stem cells (MSCs) are known to have high angiogenic potential. We hypothesized that PLGA and β-TCP scaffolds seeded with MSCs would effectively induce a potent angiogenic response. Therefore, we studied the angiogenic effects after implanting PLGA and β-TCP scaffolds seeded with isogeneic MSCs in vivo. Fifty-six BALB/c mice were equally…

Accelerated vascularization of tissue engineering constructs in vivo by preincubated co-culture of aortic fragments and osteoblasts

Biochemical Engineering Journal 2016 Volume 105, Part A, Pages 230–241

There is an urgent critical need for the development of clinically relevant tissue-engineered large bone substitutes that can promote early vascularization after transplantation. To promote rapid blood vessel growth in the engineered tissue, we preincubated aortic fragments, as well as, co-cultures of aortic fragments and osteoblast-like cells in matrigel-filled PLGA scaffolds before implantation into the dorsal skinfold chambers of balb/c mice. Despite an acceptable and low inflammatory response, preincubated aortic fragments accelerate early angiogenesis of tissue-engineered constructs; the angiogenesis was found to occur faster than that observed in previous studies. Thus, the time-period for achieving a denser microvascular network could…

Accelerating the early angiogenesis of tissue engineering constructs in vivo by the use of stem cells cultured in matrigel

Journal of Biomedical Materials Research Part A 2014 Volume 102, Issue 6, Pages 1652–1662

In tissue engineering research, generating constructs with an adequate extent of clinical applications remains a major challenge. In this context, rapid blood vessel ingrowth in the transplanted tissue engineering constructs is the key factor for successful incorporation. To accelerate the microvascular development in engineered tissues, we preincubated osteoblast-like cells as well as mesenchymal stem cells or a combination of both cell types in Matrigel-filled PLGA scaffolds before transplantation into the dorsal skinfold chambers of balb/c mice. By the use of preincubated mesenchymal stem cells, a significantly accelerated angiogenesis was achieved. Compared with previous studies that showed a decisive increase of…

Additive effect of mesenchymal stem cells and VEGF to vascularization of PLGA scaffolds

Microvascular Research 2013 Volume 90, Pages 71–79

Bone marrow derived mesenchymal stem cells (bmMSCs) are widely used for the generation of tissue engineering constructs, since they can differentiate into different cell types occurring in bone tissues. Until now their use for the generation of tissue engineering constructs is limited. All cells inside a tissue engineering construct die within a short period of time after implantation of the construct because vascularization and establishment of connections to the recipient circulatory system is a time consuming process. We therefore compared the influences of bmMSC, VEGF and a combination of both on the early processes of vascularization, utilizing the mice skinfold…

Comparably accelerated vascularization by preincorporation of aortic fragments and mesenchymal stem cells in implanted tissue engineering constructs

Journal of Biomedical Materials Research Part A 2011 Volume 97A, Issue 4, Pages 383-394

The demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineering constructs is a limited vascularization. In an attempt to accelerate the vascularization of tissue engineering constructs we compared the usage of bone marrow mesenchymal stem cells (bmMSCs) and fragments derived from the aorta in vivo. Tissue engineering constructs composed of PLGA scaffolds containing Matrigel (n = 8), aortic fragments embedded in Matrigel (n = 8), bmMSCs embedded in Matrigel (n = 8), and aortic fragments embedded in Matrigel combined with bmMSCs (n =…

Calvaria bone chamber-A new model for intravital assessment of osseous angiogenesis

Journal of Biomedical Materials Research Part A 2011 Volume 99A, Issue 2, pages 151-157

The faith of tissue engineered bone replacing constructs depends on their early supply with oxygen and nutrients, and thus on a rapid vascularization. Although some models for direct observation of angiogenesis are described, none of them allows the observation of new vessel formation in desmal bone. Therefore, we developed a new chamber model suitable for quantitative in vivo assessment of the vascularization of bone substitutes by intravital fluorescence microscopy. In the parietal calvaria of 32 balb/c mice a critical size defect was set. Porous 3D-poly(L-lactide-co-glycolide) (PLGA)-blocks were inserted into 16 osseous defects (groups 3 and 4) while other 16 osseous…

A Novel Approach for Studying Microcirculation in Bone Defects by Intravital Fluorescence Microscopy

Tissue Engineering Part C: Methods 2011 Volume 17, Issue 12, Pages 1151-1159

Angiogenic and inflammatory responses to biodegradable scaffolds were previously studied using the dorsal skinfold chamber for testing different scaffold materials. In this model, the angiogenic response originates from the soft tissue of the skin. Herein, we introduce a new model that allows the study of developing microcirculation of bone defects for testing tissue-engineered constructs. A bone defect was prepared in the femur of Balb/c mice by inserting a pin for intramedullary fixation, and a custom-made observation window fixed over the defect allowed constant observation. This study included three different groups: empty defect (control), defect filled with porous poly(l-lactide-co-glycolide), and beta-tricalcium-phosphate…

Prolongated Survival of Osteoblast-Like Cells on Biodegradable Scaffolds by Heat Shock Preconditioning

Tissue Engineering Part A 2011 Volume 17, Issue 15-16, Pages 1935-1943

The implantation of tissue-engineered constructs leads to hypoxic and physical stress to the seeded cells until they were reached by a functional microvascular system. Preconditioning of cells with heat shock induced heat shock proteins, which can support the cells to survive a subsequent episode of stress that would otherwise be lethal. Preconditioning of tissue-engineered constructs resulted in significantly higher number of surviving osteoblast-like cells (OLC). At the 6th and 10th day, angiogenic response was found comparative to poly(L-lactide-co-glycolide) (PLGA) scaffolds vitalized with either unconditioned or preconditioned OLC. However, they were significantly enhanced compared with the nonvitalized collagen-labeled PLGA scaffolds. This…

Accelerated Angiogenic Host Tissue Response to Poly(L-Lactide-co-Glycolide) Scaffolds by Vitalization with Osteoblast-like Cells

Tissue Engineering Part A 2010 Volume 16, Issue 7, Pages 2265-2279

Background: Bone substitutes should ideally promote rapid vascularization, which could be accelerated if these substitutes were vitalized by autologous cells. Although adequate engraftment of porous poly(L-lactide-co-glycolide) (PLGA) scaffolds has been demonstrated in the past, it has not yet been investigated how vascularization is influenced by vitalization or, more precisely, by seeding PLGA scaffolds with osteoblast-like cells (OLCs). For this reason, we conducted an in vivo study to assess host angiogenic and inflammatory responses after the implantation of PLGA scaffolds vitalized with isogeneic OLCs. Materials and Methods: OLCs were seeded on collagen-coated PLGA scaffolds that were implanted into dorsal skinfold chambers…

Effects of VEGF loading on scaffold-confined vascularization

Journal of Biomedical Materials Research Part A 2010 Volume 95A, Issue 3, Pages 783-792

Adequate vascularization of tissue-engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß-tricalcium-phosphate (ß-TCP) and porous poly(L-lactide-co-glycolide) (PLGA) scaffolds via collagen coating with vascular endothelial growth factor (VEGF) and studied whether the VEGF loading improves scaffold angiogenesis and vascularization. Dorsal skinfold chambers were implanted into 48 balb/c mice, which were assigned to 6 groups (n = 8 each). Uncoated (controls), collagen-coated, and additionally VEGF-loaded PLGA and ß-TCP scaffolds were inserted into the chambers. Angiogenesis, neovascularization, and leukocyte-endothelial cell interaction were analyzed repeatedly during a 14-day observation period using intravital fluorescence microscopy. Furthermore, VEGF release…

Consequences of seeded cell type on vascularization of tissue engineering constructs in vivo

Microvascular Research 2009 Volume 78, Issue 2, Pages 180-190

Implantation of tissue engineering constructs is a promising technique to reconstruct injured tissue. However, after implantation the nutrition of the constructs is predominantly restricted to vascularization. Since cells possess distinct angiogenic potency, we herein assessed whether scaffold vitalization with different cell types improves scaffold vascularization. 32 male balb/c mice received a dorsal skinfold chamber. Angiogenesis, microhemodynamics, leukocyte–endothelial cell interaction and microvascular permeability induced in the host tissue after implantation of either collagen coated poly (l-lactide-co-glycolide) (PLGA) scaffolds (group 4), additionally seeded with osteoblast-like cells (OLCs, group 1), bone marrow mesenchymal stem cells (bmMSCs, group 2) or a combination of OLCs…

Vascularization and biocompatibility of scaffolds consisting of different calcium phosphate compounds

Journal of Biomedical Materials Research Part A 2008 Volume 86A, Issue 4, Pages 1002-1011

Scaffolds for tissue engineering of bone should mimic bone matrix and promote vascular ingrowth. Whether synthetic hydroxyapatite and acellular dentin, both materials composed from calcium phosphate, fulfill these material properties has not been studied yet. Therefore, we herein studied in vivo the host angiogenic and inflammatory response to these biomaterials. Porous scaffolds of hydroxyapatite and isogeneic acellular dentin were implanted into the dorsal skinfold chamber of balb/c mice. Additional animals received perforated implants of isogeneic calvarial bone displaying pores similar in size and structure to those of both scaffolds. Chambers of animals without implants served as controls. Angiogenesis and neovascularization…