Current knowledge indicates that the molecular cross-talk between stem cells and biomaterials guides the stem cells' fate within a tissue engineering system. In this work, we have explored the effects of the interaction between the poly(L-lactide) acid (PLLA) polymer film and human adult adipose stem cells (hASCs), focusing on the events correlating the materials' surface characteristics and the cells' plasma membrane. hASCs were seeded on films of pristine PLLA polymer and on a PLLA surface modified by the radiofrequency plasma method under oxygen flow (PLLA+O 2 ). Comparative experiments were performed using human bone-marrow mesenchymal stem cells (hBM-MSCs) and human umbilical matrix stem cells (hUCMSCs). After treatment with oxygen-plasma, the surface of PLLA films became hydrophilic, whereas the bulk properties were not affected. hASCs cultured on pristine PLLA polymer films acquired a spheroid conformation. On the contrary, hASCs seeded on PLLA+O 2 film surface maintained the fibroblast-like morphology typically observed on tissue culture polystyrene. This suggests that the surface hydrophilicity is involved in the acquisition of the spheroid conformation. Noteworthy, the oxygen treatment had no effects on hBM-MSC and hUCMSC cultures and both stem cells maintained the same shape observed on PLLA films. This different behavior suggests that the biomaterial-interaction is stem cell specific.
The major challenge for stem cell translation regenerative medicine is the regeneration of damaged tissues by creating biological substitutes capable of recapitulating the missing function in the recipient host. Therefore, the current paradigm of tissue engineering strategies is the combination of a selected stem cell type, based on their capability to differentiate toward committed cell lineages, and a biomaterial, that, due to own characteristics (e.g., chemical, electric, mechanical property, nano-topography, and nanostructured molecular components), could serve as active scaffold to generate a bio-hybrid tissue/organ. Thus, effort has been made on the generation of in vitro tissue engineering modeling. Here, we present an in vitro model where human adipose stem cells isolated from lipoaspirate adipose tissue and breast adipose tissue, cultured on polymeric INTEGRA® Meshed Bilayer Wound Matrix (selected based on conventional clinical applications) are evaluated for their potential application for reconstructive surgery toward bone and adipose tissue. We demonstrated that human adipose stem cells isolated from lipoaspirate and breast tissue have similar stemness properties and are suitable for tissue engineering applications. Finally, the overall results highlighted lipoaspirate adipose tissue as a good source for the generation of adult adipose stem cells.
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Forty patients were examined with colour Doppler to study the vascularization of rectus abdominis myocutaneous flaps before operations. The accuracy of this non-invasive ultrasound technique allowed us to describe the characteristics of the blood flow, including volume and velocity, diameter of vessels and their transverse section area within the epigastric arteries which supply the superior and inferior vascular pedicles of the flap. Vessels are drawn on the skin surface so that the flap can be more precisely and rapidly dissected. We are now using colour Doppler to assess variations in the diameter of vessels and in other variables of blood flow within the vascular pedicle of the transferred flap. These evaluations before and after operation are a great help to the reconstructive surgeon in the choice of operation and will lead to an appreciable reduction in postoperative morbidity.
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