Stem cells: innovations in clinical applications

Abstract

The use of mesenchymal stem cells (MSCs) as clinical therapeutics is a relatively new avenue of study for treatment of a variety of diseases. The therapeutic impact of the MSCs is based upon their multiplicities of function and interaction with host tissues. MSCs can be anti-inflammatory, antifibrotic, antimicrobial, and regenerative, all which may improve outcomes in scenarios of damaged tissues and inflammation. Although most studies focus on utilizing MSCs to direct clinical efficacy, it is the ability to orchestrate host response in surrounding tissue that is especially unique and versatile. This orchestration of host response can be applied to a variety of clinical scenarios not only through cell-cell interactions but also through production of bioactive secreted factors. These bioactive factors include small proteins, chemokines, cytokines, and other cellular regulators. These factors have the capacity to induce angiogenesis or blood vessel development, be chemotactic, and induce cellular recruitment. MSCs also have the capacity to differentiate with the implicated environment to regenerate tissue or accommodate host tissue in a cell specific manner. The differentiation cannot only be done in vivo but also can be optimized in vitro prior to in vivo administration, potentiating the versatility of the MSCs and opening avenues for corrective therapy and cell delivery of genes. The differentiation process depends on the environment with which the MSCs are put and results in active communication between the newly administered cells host tissue. Since these properties have been identified, there are a variety of clinical trials and studies being conducted on MSCs ability to treat human disease. This review outlines the potential use of MSCs, the types of tissue, and the innovative applications of MSCs for the treatment of diseases.

Figure 1

The application of stem cells in wound treatment can be done directly with injection or topical application or indirectly through systemic administration. Direct application of MSCs to the effected region is more effective in the treatment of wounds with a significantly faster response time to the MSCs and minimization of lost therapeutic impact.

Figure 2

MSCs in environment. MSCs are both responsive and contributive to their environment. MSCs have the ability to differentiate into multiple cell types (a), which also contribute to their environment. In the orthopedic world, MSCs have the ability to transform into a regeneration of bone, cartilage, bone marrow, muscles, tendons, and connective tissue, as shown above (a). MSCs secrete healing products, which contribute greatly to their environment (b).

Figure 3

Diabetes and insulin. In the digestion of food, a diabetic patient does not create insulin, causing a glucose buildup in the bloodstream and an elevated blood sugar level.

Figure 4

In the setting of chronic lung disease, MSCs have great potential to be an alternative therapeutic. MSCs can contribute to lung regeneration and reduction of inflammation, as well as improve fluid clearance Bonfield et al. [26].

Figure 5

Asthma causes severe inflammation of the bronchial airways, making it hard to breathe. The use of MSCs as a therapeutic in this scenario caused a significant decrease in fluid blockage, as well as reduced the inflammation in the airways.