A Hydrogel Material for Plastic and Reconstructive Applications Injected into the Subcutaneous Space of a Sheep

Abstract

Soft tissue reconstruction using tissue-engineered constructs requires the development of materials that are biocompatible and support cell adhesion and growth. The objective of this study was to evaluate the use of macroporous hydrogel fragments that were formed using either unmodified alginate or alginate covalently linked with the fibronectin cell adhesion peptide RGD (alginate-RGD). These materials were injected into the subcutaneous space of adult, domesticated female sheep and harvested for histological comparisons at 1 and 3 months. In addition, the alginate-RGD porous fragments were seeded with autologous sheep preadipocytes isolated from the omentum, and these cell-based constructs were also implanted. The results from this study indicate that both the alginate and alginate-RGD subcutaneous implants supported tissue and vascular ingrowth. Furthermore, at all time points of the experiment, a minimal inflammatory response and capsule formation surrounding the implant were observed. The implanted materials also maintained their sizes over the 3-month study period. In addition, the alginate-RGD fragments supported the adhesion and proliferation of sheep preadipocytes, and adipose tissue was present within the transplant site of these cellular constructs, which was not present within the biomaterial control sites.

Injectable preformed scaffolds with shape-memory properties

“…Shape memory allows for this function. Furthermore, the ability of these materials to reassume specific, predefined shapes after injection is likely to be useful in applications such as tissue patches (e.g., cardiac patches) where one desires a patch of a specific size and shape, or when one desires to fill a large defect site with multiple smaller objects that pack in such a manner to leave voids that enhance diffusional transport to/from the objects and the host, and promote vascularization around each object (30,31). The polymeric system can be used as a delivery device for biomolecules, including proteins, as long-term sustained release of encapsulated rhodamine-labeled BSA and GM-CSF demonstrate.…”

Once fat was fat and that was that : our changing perspectives on adipose tissue

“…108 ADSCs and fat transplantation have been successfully used after trauma and surgical resection such as mastectomy, 109,110 where ADSCs help to abrogate problems with angiogenesis and the long-term viability of grafts. [111][112][113] ADSCs have also been used to treat lipodystrophy, 114 which has become common due to side effects of antiretroviral therapies (ART) in HIV-positive patients. 115,116 These ADSCs are expanded in number in vitro and differentiated into mature adipocytes using a cocktail including insulin, the cAMP inducer IBMX, a PPARg agonist indomethecin and a low concentration of a glucocorticoid such as dexamethasone.…”

Growth factor delivery for oral and periodontal tissue engineering

“…A variety of new injectable materials such as hydrogels are also being developed for growth factor delivery applications and have been of special interest [56,57]. These injectables are especially attractive because, in clinical application, they can allow for minimally invasive delivery of inductive molecules.…”