Rationale for the design of 3D-printable bioresorbable tissue-engineering chambers to promote the growth of adipose tissue

Abstract

Tissue engineering chambers (TECs) bring great hope in regenerative medicine as they allow the growth of adipose tissue for soft tissue reconstruction. To date, a wide range of TEC prototypes are available with different conceptions and volumes. Here, we addressed the influence of TEC design on fat flap growth in vivo as well as the possibility of using bioresorbable polymers for optimum TEC conception. In rats, adipose tissue growth is quicker under perforated TEC printed in polylactic acid than non-perforated ones (growth difference 3 to 5 times greater within 90 days). Histological analysis reveals the presence of viable adipocytes under a moderate (less than 15% of the flap volume) fibrous capsule infiltrated with CD68 + inflammatory cells. CD31-positive vascular cells are more abundant at the peripheral zone than in the central part of the fat flap. Cells in the TEC exhibit a specific metabolic profile of functional adipocytes identified by 1 H-NMR. Regardless of the percentage of TEC porosity, the presence of a flat base allowed the growth of a larger fat volume (p < 0.05) as evidenced by MRI images. In pigs, bioresorbable TEC in poly[1,4-dioxane-2,5-dione] (polyglycolic acid) PURASORB PGS allows fat flap growth up to 75 000 mm 3 at day 90, (corresponding to more than a 140% volume increase) while at the same time the TEC is largely resorbed. No systemic inflammatory response was observed. Histologically, the expansion of adipose tissue resulted mainly from an increase in the number of adipocytes rather than cell hypertrophy. Adipose tissue is surrounded by perfused blood vessels and encased in a thin fibrous connective tissue containing patches of CD163 + inflammatory cells. Our large preclinical evaluation defined the appropriate design for 3D-printable bioresorbable TECs and thus opens perspectives for further clinical applications. Reconstruction of adipose tissue defects after surgery (e.g. mastectomy) or trauma remains a major surgical challenge. Numerous tissue-engineering techniques were attempted experimentally. It includes repair methods such as autologous or heterologous fat grafting or also transfer of vascularized adipose tissue from a donor site, also called a fat flap. The limitation of this latter method is that the fat flap requires a sufficient amount of available fat in the donor site, which often leads to deformity at the donor site. Moreover, donor flap sites may not

Techniques and Innovations in Flap Engineering: A Review

“…Qin et al 24 implanted a biodegradable film on the inner surface of TECs, separating native tissue from the silicone chamber, which also led to doubling in flap size and to a thinner, less constraining capsule. Faglin et al 25 used a bioabsorbable polymer to produce degradable TECs. The maximal volume of absorbable TEC flaps did not differ from the traditional ones.…”

Current Advances in 3D Bioprinting for Cancer Modeling and Personalized Medicine

“…Traditionally, the materials used for 3D printing in medicine are made of inert and acellular materials, such as plastics [ 7 ]. Among those materials, some are bio-compatible and can thus be used for implantation [ 8 ]; other materials are degradable and are used as guides for soft tissue reconstruction, e.g., breast reconstruction after cancer surgery [ 9 ]. Recently, a new field of research in 3D printing has emerged: 3D bioprinting.…”

Breast Reconstruction Using a Three-Dimensional Absorbable Mesh Scaffold and Autologous Fat Grafting: A Composite Strategy Based on Tissue-Engineering Principles

“…Diced cartilage graft has been applied widely for rhinoplasty, with rare resorption and stable outcomes over time. [2][3][4] The present study adopted diced cartilage pieces smaller than 0.2 mm in diameter, while 0.5-to 1-mm diced cartilage was more widely adopted in the literature. [2][3][4][5] Since there were no studies reporting the potential effect on viability associated with the diameter of diced cartilage, using diced cartilage smaller than 0.2 mm will lack typicality and may lead to a potential bias to some extent.…”

“…Preclinical protocols in rats and pigs have found the proof of concept of Morrison et al by documenting tissue growth within the implantable chamber in an average time of 90 days during magnetic resonance imaging follow-up. 3…”