Therapeutic Potential of Adipose-Derived Stem Cells and Their Secretome in Reversible Alopecias: A Systematic Review

Androgenic alopecia (AGA) and alopecia areata (AA) are two highly prevalent conditions, affecting both men and women of a wide range of ages, which strongly impact their quality of life and self-esteem. Both pathologies are deemed to be reversible, although conventional therapies have shown limited scope and efficacy. New therapeutic approaches, focusing on the degenerative changes that take place in the hair follicle, are needed to achieve better outcomes. For instance, adipose-derived stem cells (ADSC), abundant and easy to obtain, hold great potential in follicular regeneration. ADSCs can be isolated as stromal vascular fraction (SVF) by the enzymatic digestion of the lipoaspirate or as nanofat by the mechanical breakdown of adipocytes. In addition, commercial preparations of the conditioned medium of the ADSCs secretome (ADSC-conditionate medium [CM]) have entered the market as an appealing alternative because of their comparatively lower cost and accessibility. A search was conducted, crossing relevant terms, on PubMed Central and Google Scholar. Criteria for inclusion were studies in the past 10 years on humans with AGA or AA, where either SVF, nanofat, or ADSC-CM was tested as the main treatment. Eleven publications qualified: two studied nanofat, three, ADSC-CM, and six, SVF, either individually or in combination with other therapies. Only one randomized controlled trial (RCT) was found and classified as evidence 2b according to the Sackett scale. The rest were case-control studies or case series with small samples and no control, graded as evidence 3b and 4. A meta-analysis could not be conducted due to the heterogenicity of the study designs. Given the evidence obtained, Level D NICE recommendation was established. However, we consider that the positive findings are sufficiently consistent to support the elaboration of further RCTs that share criteria and methods.