Endocrine Function of Adipose Tissue and Tissue Regeneration

Adipose tissue is not merely an energy storage site but also an endocrine organ that secretes hormones and cytokines, playing a crucial role in metabolic homeostasis and tissue regeneration. However, existing tissue engineering technologies have struggled to effectively replicate the structure and function of adipose tissue. To overcome these limitations, the research team developed a novel assembly technique that preserves the endocrine function of adipose tissue while allowing integration with skin tissue.

Embedded 3D Bioprinting and Optimized Bioink

The research team applied an embedded 3D bioprinting technique to stably fabricate adipose tissue units. To achieve this, rheological analysis and computational fluid dynamics simulations were conducted to optimize the viscoelastic properties of the bioink.

Additionally, a hybrid bioink containing alginate was developed to limit cell migration and promote adipocyte maturation in a densely packed environment. Experimental results showed that bioink containing 0.5% alginate resulted in the highest cell density and significantly increased the expression of genes promoting adipocyte maturation.

Optimization of Adipose Tissue Size and Spacing

The research team determined that a tissue unit size of 600 μm provides the highest cell viability and maturation. Moreover, when the spacing between adipose units was less than 1,000 μm, endocrine signal transmission was maximized.

Based on these findings, a customized wound healing platform using 3D printing was developed to evaluate skin cell motility. Experimental results showed that the presence of adipose units significantly increased skin cell migration, achieving over 80% wound closure within 16 hours, with the highest migration observed at a spacing of 1,000 μm between adipose units.

Verification of Skin Regeneration Effects Through Animal Studies

To assess the regenerative effects of the adipose tissue modules, the research team implanted the modules into a nude mouse model with skin injuries. The results showed increased vascularization and enhanced epidermal regeneration. Laser Doppler perfusion imaging (LDPI) analysis confirmed improved blood supply, while immunohistochemical analysis demonstrated increased expression of CD31, K10, and involucrin, markers associated with skin regeneration.

Future Research Directions

This study presents a precise tissue assembly technique for fabricating composite adipose-skin tissues. The approach is distinguishable from conventional bioprinting methods, as it allows for the flexible integration of multiple tissue modules, including vascular and skin tissues.

- Authors (Pusan National University)

 · First author: Byoung Soo Kim (School of Biomedical Convergence Engineering)

 · Corresponding authors: Jae-Seong Lee (Department of Biomedical Convergence Engineering), Minjun Ahn (Medical Research Institute)

- Title of original paper: 3D Bioprinting-Assisted Tissue Assembly of Endocrine Adipose Units for Enhanced Skin Regeneration

- Journal: Advanced Functional Materials

- Web link: https://doi.org/10.1002/adfm.202419680 

- DOI: 10.1002/adfm.202419680