Hair growth: Adipose tissue-derived stem cells appear successful

Key Points

Adipose tissue-derived stem cells display multi-lineage developmental plasticity, very much like bone marrow-derived mesenchymal stromal cells (BM-MSCs), and can differentiate into several cell lines, including adipocytes, chondrocytes and osteoblasts, as well as endothelial and neural lineages.

Furthermore, ADSCs are known to have various cytokine-secreting properties and beneficial paracrine effects on surrounding cells or tissues through secretion of multiple angiogenic and antiapoptotic growth factors, including vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF).

Kyu Han Kim, M.D., Ph.D., professor of the department of dermatology, Seoul National University Hospital, Jongno-gu, Seoul, Korea, and fellow researchers conducted a study to determine whether these paracrine effects of the ADSCs can promote hair growth.

In the study, the ADSCs harvested from human volunteers were cultivated, and the ADSC-conditioned media (CM) was then applied to ex-vivo human hair organ cultures. It also was topically applied and subcutaneously injected in mice. The cellular proliferations and hair-growth-accelerating effects of ADSC-CM were then evaluated, respectively.

Results showed that the ADSC-CM increased the proliferation of the dermal papilla cells (DPCs) and the HaCaT cells.

In a cell cycle analysis, ADSC-CM shortened G1 arrest and prolonged the synthesis and mitosis phases in the dermal papilla cells. Other results showed that the ADSC-CM induced the anagen phase and promoted hair growth in the experimental mice. It also enhanced the elongation of hair shafts in the ex-vivo human hair organ cultures.

"By modulating the cell cycle and activating the anagen phase in the hair cycle, the application of the ADSCs appear to promote hair growth by increasing the proliferation of the dermal papilla cells and possibly the HaCaT epithelial cells. We noticed less of an influence of the ADSCs on the proliferation of HaCaT cells and organ culture, with relatively narrow therapeutic concentrations of ADSC-CM," Dr. Kim says.

Previous studies

In previous studies, Dr. Kim identified secretory factors derived from ADSCs by ELISA and proteomic analysis, including several factors related to IGF binding protein precursors, PDGF, bFGF, keratinocyte growth factor (KGF), HGF, VEGF and fibronectin.

According to Dr. Kim, all of these factors are well-documented as being related to hair growth stimulation, and it is not unlikely that some secretory factors from ADSCs may be positive regulators of hair follicles and, indeed, promoters of hair growth. Nevertheless, this still must be proven beyond doubt, Dr. Kim cautions.

According to Dr. Kim, it would be premature to extrapolate the results and directly apply them to humans, as the stimulatory effects observed on the dorsum of mice may not be the same on the human scalp, and the thickness and other characteristics of human hair are different. Furthermore, the cause of hair loss may be different.

Dr. Kim says no clinical trials with ADSCs are planned yet, and that research efforts should mainly be concentrated on the more solid mechanisms of promoting hair growth.

"Before applying our experimental methods to the treatment of patients, the exact cause of hair loss should be primarily solved. Furthermore, we are not fully aware of the main cause of most types of female pattern hair loss. However, once these variables become clearer, we can and should go forward with such novel approaches for hair loss," Dr. Kim says.

Disclosure: Dr. Kim reports no relevant financial interests.