These and other experiments conducted by our group demonstrated the participation of sympathetic innervation in achromotrichia and confirmed that pain is a powerful stressor in this model. But it remained to detail the mechanisms involved,” Cunha said.Earlier studies had found that pain-related stress was also involved in the development of hair and skin pigment producing cells called melanocytes.Scientists had discovered that unspecialised stem cells in the hair follicle bulb “mature” too soon under stress.“In a young individual the cells are undifferentiated, like all stem cells, but with ageing, they gradually differentiate. Once the process is complete they stop producing the melanocytes which produce melanin,” Cunha said.“We used various methodologies to show that intense sympathetic activity speeds up differentiation significantly. In our model, therefore, pain accelerated the ageing of melanocyte stem cells,” he added.Few days into the study, the researchers found that all of the pigment-regenerating stem cells were lost.When the researchers compared the genetic activity of mice which received the injection of resiniferatoxin, developing pain, stress and fur colour loss, with those of mice injected with a placebo, they found that a gene which played a role in producing the cell division-related protein called CDK (cyclin-dependent kinase) was involved.In a follow up experiment when the researchers treated mice with a CDK inhibitor, they found that melanocyte stem cell differentiation, along with fur colour loss was prevented.
