The importance of stem cell engineering in head and neck oncology.

Head and neck squamous cell carcinoma is the sixth leading cause of cancer worldwide. The most common risk factors are carcinogens (tobacco, alcohol), and infection of the human papilloma virus. Surgery is still considered as the treatment of choice in case of head and neck cancer, followed by a reconstructive surgery to enhance the quality of life in the patients. However, the widespread use of artificial implants does not provide appropriate physiological activities and often cannot act as a long-term solution for the patients. Here we review the applicability of multiple stem cell types for tissue engineering of cartilage, trachea, vocal folds and nerves for head and neck injuries. The ability of the cells to self-renew and maintain their pluripotency state makes them an attractive tool in tissue engineering.

Mesenchymal stem cell related therapies for cartilage lesions and osteoarthritis.

Osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage degradation, synovitis, subchondral bone sclerosis and osteophyte formation. Current therapeutic approaches for OA are not curative and only temporarily alleviate symptoms. In recent years, pre-clinical experiments and clinical trials have demonstrated that mesenchymal stem cell (MSC) related therapy is a promising option for the treatment of cartilage lesions and OA. MSCs isolated from bone marrow (BMSCs) have been widely used in animal models and clinic practice to demonstrate their chondrogenic potential, however the incidence of BMSC donors is low. Adipose derived mesenchymal stem cells (AMSCs) are a more easily accessible source of stem cells for OA treatment. MSC related therapies for cartilage lesions and OA include tissue engineering of MSC transplantation, scaffold-free injection of stem cells and cell-free injection of exosomes into the injured joints. Although a great deal of effort is required at the basic and clinical research fronts, the promise is that improved cell-based therapies will ultimately lead to the repair of damaged or diseased joints, and MSC exosome therapy for OA could be a safer, cheaper and a more effective treatment modality. MSC related therapy is predicted to become a regular and routine regenerative medicine for OA treatment in future clinical practice.

Optimal Control of One-dimensional Cellular Uptake in Tissue Engineering.

A control problem motivated by tissue engineering is formulated and solved in which control of the uptake of growth factors (signaling molecules) is necessary to spatially and temporally regulate cellular processes for the desired growth or regeneration of a tissue. Four approaches are compared for determining 1D optimal boundary control trajectories for a distributed parameter model with reaction, diffusion, and convection: (i) basis function expansion, (ii) method of moments, (iii) internal model control (IMC), and (iv) model predictive control (MPC). The proposed method-of-moments approach is computationally efficient while enforcing a non-negativity constraint on the control input. While more computationally expensive than methods (i)-(iii), the MPC formulation significantly reduced the computational cost compared to simultaneous optimization of the entire control trajectory. A comparison of the pros and cons of each of the four approaches suggests that an algorithm that combines multiple approaches is most promising for solving the optimal control problem for multiple spatial dimensions.