Hair Loss and Regulating Stem Cell Metabolism

New research has identified a mechanism that appears to be able to prevent hair loss. A group of researchers in Helsinki and Cologne Germany have demonstrated that a protein known as Rictor holds a key role in the process.

Hair follicle stem cells promote hair growth and can also prolong their life by switching their metabolic state. Environmental factors such as ultraviolet radiation damage our skin and other tissues daily. The body continuously removes and renews the damaged tissues. Human sheds about 500 million cells daily and a quantity of hairs weighing a total of 1.5 grams.

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Dead material is replaced through specialized stem cells that promote tissue growth. The function of tissues is dependent on the health and activity of these stem cells. Impaired activity will result in the aging of the tissues.

The critical role of stem cells and aging has been established, however little is known about the mechanisms that regulate long-term maintenance of these vital cells. The hair follicle which is well understood and has clearly identifiable stem cells is the prefect model system for researchers to study this question.

At the end of a hair follicle’s regenerative cycle and when a new hair is created, stem cells return to their specific location and resume a quiescent state. The most important finding in the research team’s study is that the return to the stem cell state requires a change in the cell’s metabolic state. The cells switch from glutamine based metabolism and cellular respiration to glycolysis. This is a shift triggered through a signal that is induced by the Rictor protein in response to the low oxygen concentration in the tissue. The study demonstrated that the absence of this protein impaired the reversibility of the stem cells. This initiated a slow exhaustion of the stem cells and loss of hair due to aging.

The team created a genetic mouse model for the purpose of studying the Rictor protein. They observed that hair follicle regeneration and cycle were delayed quite significantly in mice who lacked the protein. Older mice suffering from a deficiency of this protein showed a gradual decrease in their stem cell which resulted in hair loss.

Additional research will be conducted to investigate how the pre-clinical findings might be utilized in human stem cell biology and also lead to drug therapies that would protect hair follicles from aging. The mechanisms found in the recent study might possibly be utilized in preventing loss of hair.

The team was most exited about their observation that the application of a glutaminase inhibitor was able to restore function of the stem cells in the Rictor deficient mice. This proved the principle that by modifying metabolic pathways, a powerful way to boost the regenerative capacity of our tissues occurred.

To view the original scientific study click below

Glutamine Metabolism Controls Stem Cell Fate Reversibility and Long-Term Maintenance in the Hair Follicle

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