A group of clinicians involved in delivering stem cell transplants to patients to treat various age-related conditions have observed temporary reversal of hair graying following treatment. Their open access paper is offered in the spirit of "look at this interesting thing that happened," and there is no deep analysis of underlying mechanisms - though it isn't hard to speculate based on what is known. The approach used mesenchymal stem cells (MSCs), which in the current standard treatment models are thought to produce benefits through signaling that alters the behavior of native cells. The transplanted cells don't live for very long and don't themselves work to maintain tissues. MSC transplantation is known to temporarily reduce chronic inflammation and measures of oxidative stress in tissues, as well as spurring native stem cells to restored activity.
Hair graying is generally considered to be some mix of (a) damage and decline of the melanocyte cells responsible for coloring hair, present in the hair follicles, and (b) dysfunction in the activity of melanocytes and related cell populations caused by the higher levels of oxidative stress that accompany aging. These cells are more sensitive to that increase than most, and so this is one of the first signs of aging. Hair greying can be reversed by treatments that suppress oxidative stress, as has been demonstrated in recent years. So joining all the dots, it isn't unreasonable to propose that stem cell transplantation is temporarily reducing oxidative stress to levels low enough to put melanocytes back to work - but that would have to be confirmed with more careful studies.
Adipose derived autologous mesenchymal stem cells have been transplanted and tested for their ability to regenerate tissues for several indications. We treated a total number of 14 patients between the age group 38-75 years, out of them 4 subjects had completely grey hair. Three subjects were males and one female. While treating these patients for their various age related neurodegenerative disorders with autologous mesenchymal stem cells for their regenerative and rejuvenating properties, we accidentally observed a transition of hair colorations from mostly grey to black in all the 4 elderly patients. Each patient received more than one session within a time frame of 2-3 weeks. Each time the MSCs were administered by spinal intrathecal route (20 million) and intravenously (20 million) after over a period of 20 minutes. There were no notable complications post transplantations. We observed remarkable improvement in the neurological status (being reported separately) and the only adverse effect was transient headache.
In observed patients about 50% of the hairs were seen turning black after duration of 3-6 weeks. This was observed on the scalp and on the beard as well. However, the effect was not permanent; as the age progressed the greying process continued. The longest period of follow up was 20 months for all the 4 patients. All the subjects continue to have some black hairs but were now lesser in density and number. This may be through positive activation and regeneration of melanocyte stem cells in the hair follicular niche. In this paper we intend to report this unique observation which may lead to further research. We do not view MSCs as a treatment modality for grey hair. However this is an incidental finding, so far not reported in the literature.