How the endocrine system affects our skin colour Vitiligo is notoriously confusing. Scientists call it a multifactorial condition… Meaning that a variety of different factors can trigger it and it can follow multiple different pathways. The depigmentation process itself can develop in a number of different ways. And the factors involved can vary from one […] The post Vitiligo and hormones appeared first on The Vit Pro (A Vitiligo Blog).
How the endocrine system affects our skin colour
Vitiligo is notoriously confusing. Scientists call it a multifactorial condition… Meaning that a variety of different factors can trigger it and it can follow multiple different pathways. The depigmentation process itself can develop in a number of different ways. And the factors involved can vary from one individual to the next, or even change over time. Genetics, environment, lifestyle and a whole host of other influences and associated health issues, can play a part in its onset and development… Hormonal factors being just one of many. And, as if this were not confusing enough, the relationship between vitiligo and hormones is pretty complex in itself.
As ever, researching the subject for this blog has left me with at least as many questions as answers. Which hormones affect skin colour? Why do they sometimes lead to pigment loss? And are they always a factor in the vitiligo process? As a non-scientist, I can’t hope to do more than scratch the surface of this fascinating subject and maybe prompt others to do some deeper research of their own. But, for now, I’ll start with the most basic question…
What are hormones?
Even those of us who were among the 50% in our biology class that made the top 50% possible (ha, ha) will have heard of hormones and have some idea what they are. But what exactly do they do in the human body?
When we hear the word hormones the majority of us probably think about mood swings and other symptoms that typically occur when we enter a new life stage. Acne in our teens, mood swings in adolescence and hot flushes in menopause are some of the stereotypical images that come to mind when we think of hormones. But, of course, there is a whole lot more to them than that.
Our endocrine system, which produces and controls the function of hormones throughout our body consists of a complex network of glands and organs. And the hormones themselves act as chemical messengers that regulate a massive number of biological functions. These little messengers are released into the bloodstream and carried to specific cells or tissues, where they regulate numerous different crucial processes… Processes such as metabolism, growth and development, mood, sexual function and reproduction.
What happens when the endocrine system goes wrong?
A healthy endocrine system produces just the right amount of each hormone at the right time for it to do its allocated job. But when it malfunctions an imbalance of hormones can occur, leading to all kinds of unpleasant symptoms, like mood swings, unexpected weight changes and fatigue. Hormonal imbalances can also disrupt normal growth and metabolism and develop into a variety of chronic conditions, such as thyroidism, diabetes and various autoimmune diseases.
So, which hormone imbalances affect pigmentation?
There is no single hormone that affects the pigmentation process, but rather a number of them. The primary one being MSH (melanocyte-stimulating hormone). MSH is produced by the pituitary gland, hypothalamus and skin and is the main regulator of melanin production.
Thyroxine (T4) and triiodothyronine (T3), produced by the thyroid gland, affect nearly all of our cells. In particular, they regulate metabolism, growth and development but they also stimulate melanin synthesis in the hair follicles.
The female sex hormones oestrogen and progesterone, produced by the ovaries and crucial to reproduction, can also affect skin pigment by stimulating melanocytes to increase melanin production.
And ACTH (adrenocorticotropic hormone), produced by the pituitary gland, is released in response to stress. But it too stimulates melanin production.
I said it was confusing, didn’t I?
How might these hormones affect vitiligo?
Hormonal imbalances, whilst they can trigger depigmentation, may or may not be a direct factor in all cases and types of the condition. But what is clear is that there is an association between the functioning of these particular hormones and vitiligo. For example…
Studies have found lower levels of α-MSH (which is a specific MSH molecule) in the blood of vitiligo subjects than in healthy individuals, indicating that reduced levels of this hormone go hand in hand with depigmentation and impaired immune response.
It seems there is a strong correlation between thyroid disease and vitiligo, which is not surprising since both of the thyroid hormones affect the pigmentation process. But, despite the high incidence of vitiligo and autoimmune thyroid conditions like Graves disease and Hashimoto’s thyroiditis, most people with vitiligo evidently have levels of these hormones that are within the normal range. So thyroid hormones are presumably not a key factor for everyone.
A complex relationship exists between the female sex hormones (oestrogen, in particular) and the vitiligo process involving hormonal fluctuations, oxidative stress and melanocyte function.
And there is an equally complex relationship between adrenocorticotropic hormone (ACTH) and vitiligo. This involves adrenal insufficiency, leading to raised levels of ACTH and an autoimmune response resulting in both hyper- and hypopigmentation.
Did I mention, vitiligo is complex?
Is hormone therapy the answer to vitiligo?
As with all things biological and medical, nothing is ever as simple as we would wish it to be. And, if you could easily cure all cases of vitiligo by taking a pill to boost or suppress certain hormones, I’m pretty sure the research community would have cracked that nut by now. And it is certainly not something to dabble in without expert medical guidance. (For example, taking HRT may make your vitiligo worse. And
ACTH supplementation is no guarantee of repigmentation and carries long term health risks.)
But it does look likely that new generations of pharmaceuticals for vitiligo will include classes of drugs that target the endocrine system.
As long ago as 1995 research indicated that various kinds of hormone therapy can help to halt or reverse depigmentation in certain cases. For example, some studies demonstrated that patients with generalised vitiligo improved when given oral powder mixture of sex hormone and thyroid hormone.
Then some oral corticosteroids, like dexamethasone pulse therapy can help to manage the autoimmune response that causes vitiligo. And apparently this counts as a type of hormone therapy.
Melanotan I and II
Back in the 1980s researchers at the University of Arizona developed a synthetic analogue of a-MSH hormone as a cosmetic product (Melanotan I) to provide a “sunless tan”. Limited trials over the following decade confirmed its potential for tanning and it became commercially available. But it had worrying side effects and there was no clinical research into its longer-term risks.
Melanotan I has no licence for recreational use and sales of it are therefore illegal. So, if you see it for sale, be aware that it is not considered safe to use. It is also open to counterfeiting by unscrupulous suppliers and has often been contaminated with with dangerous ingredients. (Its successor, Melanotan II was meant to be an improved version but has even more hazardous side effects and is also not legitimately available for general use.)
SCENESSE
However, the Australian pharmaceutical company Clinuvel subsequently developed Melanotan I, called afamelanotide or SCENESSE®, and this now has approval for use in some countries for erythropoietic protoporphyria (a rare inherited disease causing severe intolerance to light).
While it has no approval yet for vitiligo treatment, SCENESSE is in late stage clinical trials for this use. This is obviously very good news, although, like all drugs, it will not be a perfect cure. It will no doubt have its shortcomings and side effects. And it will not work equally for everyone. However, it will be an exciting landmark in pharmaceutical vitiligo treatment because it will be the first systemic (i.e. whole body) treatment that does not act by suppressing the immune system.
Prostaglandin analogues
Another current avenue of vitiligo research involves the use of prostaglandin analogues and phosphodiesterase inhibitors, which you can check out on this link.
Do hormones hold the key to a vitiligo cure?
I began this post by highlighting the fact that vitiligo is a complex, multifactorial condition. On the face of it, this is a bad thing. It’s what makes vitiligo so hard to understand and to treat. But, in the course of researching my topic, I have come to realise that this is a two-edged sword. After all, vitiligo has many different triggers and pathways. So it stands to reason that these must also present many different ways of approaching a cure.
Traditional and alternative therapies first demonstrated this fact. For example, some natural remedies act to soothe the inflammation associated with vitiligo. Others boost antioxidant levels to offset the oxidative stress linked to the vitiligo process. Some sensitize the skin to UV light in order to stimulate melanin production. And others aim to correct nutritional deficiencies that may occur alongside pigment loss.
Medical science uses exactly the same approaches to vitiligo treatment, but in a pharmaceutical / clinical context. (Plus more sophisticated interventions involving genetics, surgical procedures and immunosuppressant drugs.) All of these techniques, in their various ways, aim to interrupt or block the vitiligo process at some point in its development. And attempting to restore normal pigmentation via hormonal manipulation is just one more option open to vitiligo research.
Final thought
Fortunately for me, nutrition proved to be the key that unlocked my recovery. For others, topical creams and / or phototherapy prove effective. But for many more, a reliable and safe vitiligo therapy still feels like an impossible dream. And yet I think it is encouraging that so much varied research is ongoing, with different teams of scientists approaching the challenge from different angles (a hormonal approach being just one). Because, as we know only too well, what works for one person does not always work for another. So the more treatment options that vitiligo sufferers and their doctors have tochoose from in the future, the better it will be for us all.
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