The term "mesenchymal stem cell therapy" covers a very broad range of cell sources and cell capabilities. Arguably the category needs to be thrown out and replaced with a more detailed taxonomy. The results of mesenchymal stem cell therapy in one clinic can be wildly different from those in another due to small differences in protocol, even given a similar source of cells.
Taken as a whole, this class of therapy appears to fairly reliably suppress chronic inflammation for a time, while unreliably provoking increased regeneration and tissue maintenance. Transplanted cells near all die rapidly rather than integrating into tissues, and results are thus achieved via the signaling generated for a brief time by the transplanted stem cells.
In this review paper, researchers discuss some of the evidence for mesenchymal stem cell therapies to improve structure and function in aged skin, which is an area of clinical practice in which one needs to follow references somewhat more carefully than is usually the case, given the sizable contingent at that end of the community that likes to play fast and loose with the truth.
Aged skin is highly associated with loss of function and structural degeneration. With aging, the skin naturally loses its collagen content and elastic fibers become deranged. Additionally, aged skin demonstrates an increase in oxidant activity, and an increase in the production of matrix metalloproteases (MMP), which are typically involved in matrix degradation. Additionally, exposure to UV light is known to promote premature aging of the skin, namely photoaging. Thus, rejuvenation therapies, which focus on the prevention and reversal of skin aging are in high demand in our society, which increasingly aims to maintain a youthful appearance and improve their health.
Adipose derived MSCs (AD-MSCs) have been gaining attention in skin antiaging therapy because of their efficient re-epithelization and secretion of several growth factors necessary for skin regeneration. In recent years, researchers observed histological and structural modifications in aged facial skin after the injection of expanded AD-MSCs, collected from fat removed by liposuction. Treatment with AD-MSCs caused an increase in elastic fibers in the superficial layer of the dermis and modified the collagen and reticular fiber networks, which became more arranged. Subsequently, AD-MSCs were observed to induce complete regeneration of solar elastosis in photoaged skin.
The transplantation of AD-MSCs leads to complete regeneration of dermal elastic matrix components, including oxytalan, elaunin, and elastin fibrillary networks. In solar-aged skin, the normal elastin matrix is usually lost, and AD-MSC-mediated treatment successfully reversed the inhibition of precursor molecules involved in neoelastinogenesis.
Another way to use AD-MSCs in antiaging therapy, in a "cell-free" method of treatment, is by using extracellular vesicles (EVs), which have several advantages over stem cells and their safety issues. Adipose-derived mesenchymal stem cells extracellular vesicles (AD-MSCs-EVs) have anti-photoaging potential and were analyzed as subcutaneous injections in photoaged mice models. The treatment resulted in a decrease in skin wrinkles and promotion of epidermal cell proliferation. Additionally, macrophage infiltration and reactive oxygen species (ROS) production were reduced, which inhibited MMP activation and collagen degradation.