Hair Whitening

00:01 Welcome. Here's another talk that's going to be really interesting to all of us.

00:06 Because as we all get older, you will undoubtedly encounter the fact that your hair also grays or even whitens out.

00:16 So what is happening with this? Santa Claus wasn't even born with white hair.

00:21 He probably had black hair when he was in his youth.

00:24 But as he got older, then there were changes in the structure and the function of the hair follicles, in particularly the stem cells that sit as part of the hair root.

00:37 Take a close look at this hair follicle.

00:40 The brown shaft extending from the follicle is the visible part of our hair below the surface. Within the skin lies a critical region called the hair bulge that contains melanocyte stem cells, often abbreviated as Mescs, which hold the key to maintaining hair pigmentation.

01:02 When a new cycle begins, some of these melanocyte stem cells migrate from the bulge to the bulb at the base of the follicle.

01:08 These stem cells differentiate into melanocytes in this region and start producing melanin, which gives the hair its color.

01:19 All of this happens during antigen, but it is during its final stages when melanosomes are synthesized and transferred to the hair shaft and melanin is produced.

01:30 What happens when those melanocytes that were supposed to be making the melanin quit doing their job, and a variety of things drive that process? So aging. And we'll talk about some of the mechanisms involved in aging and or stress.

01:46 Yes. Believe it or not, a lifetime of being a type A medical student can drive you to get gray or white hair sooner.

01:53 Yes, stresses in particular nor noradrenaline is responsible for changing the synthesis of melanin produced by the melanocytes.

02:04 Okay, so those two factors and some of the mechanisms that drive those will affect the number and the activity of the melanocyte stem cells.

02:13 Those will decrease. And you then get less melanin being produced to get into the hair itself. That reduced melanin production causes the hair to be white or gray.

02:25 It all depends on how much normal pigment is being produced.

02:29 So how is this happening? So stress. Remember, stress causes an adrenergic stimulation.

02:37 There actually, you have nerve fibers.

02:39 Sympathetic nerve fibers that end and influence the activity of the hair bulge.

02:47 And with too much noradrenaline, you reduce that migration of the melanocyte stem cells into the hair bulb.

02:55 So that will actually markedly reduce the amount of melanin obviously being produced in that location. You also get reactive oxygen species.

03:04 We've talked about this with with UV exposure overall.

03:08 But with age you don't you don't block or you don't reduce the breakdown of reactive oxygen species. And with inflammation you may get more reactive oxygen species.

03:22 What are one of the reactive oxygen species in particular? Hydrogen peroxide. If you wanted to bleach your hair, what would you use? Hydrogen peroxide.

03:31 So in fact, you are dumping bleach directly onto your hair.

03:37 And that's why it can also with age and with reactive oxygen species, inflammation can drive that kind of fading of the hair.

03:46 The less less pigmentation, UV damage and UV damage is directly affecting the melanocytes, but is also directly affecting their ability to or your ability to make and or break down reactive oxygen species and then reduced catalase expression.

04:04 As we age, the epithelial cells make less catalase, which catalase is good for breaking down hydrogen peroxide.

04:11 So hopefully this all kind of makes sense.

04:13 And it seems like it's it's inevitable that all of us will tend to get whiter or grayer hair as we age. That's okay.

04:23 Own that. Risk factors.

04:25 So genetics. So clearly if you make more hydrogen peroxide when you get inflamed, if you make less catalase, if you make less melanin overall.

04:35 Those are all kind of going to affect your ability to or your ability to pigment your hair. Hormonal changes will drive this.

04:43 Environmental factors such as sun exposure and pollution.

04:47 So UV damage, etc.. And finally lifestyle factors.

04:50 And the more you get stressed, the more that you are at risk for getting less pigmentation to your hair.

04:57 There is an apocryphal story about Marie Antoinette the day before she was due to go to the guillotine during the French Revolution, that she had had black hair.

05:05 The stress overnight and went to white hair.

05:07 I don't think that happens quite that quickly, but stress clearly does drive hyperpigmentation and hair.

05:16 How do we manage this? Well, we can try to reduce stress. We can try not to age. Good luck with that.

05:21 So there really is no good treatment.

05:22 And if you really don't like the look of it, die it.

05:26 And that's pretty much all you can do.

05:28 So with that, I think we've discussed a very interesting topic.

05:33 Hopefully you understand now what drives this.

05:35 Why we just need to embrace it and enjoy the fact that we all get a few gray hairs.