The Connection Between Your Brain, Stress and Skin

Psychological stress occurs when you are under mental, physical, or emotional pressure (stress). If you feel or think that the stress exceeds your ability to cope with your brain and stress hormones namely corticotropin-releasing hormone (CRH), glucocorticoids, and epinephrine are released. These hormones trigger a range of physiological and behavioral changes that try to adapt the body to the stress. If the stress responses are inadequate or excessive, they can trigger adverse physiological events. It has been shown that stress can trigger and/or exacerbate multiple conditions:

  • Cardiovascular disease
  • Migraine
  • Multiple sclerosis
  • Epileptic seizures
  • Neurodegeneration

This blog post is a summary of recent research "Brain-Skin Connection: Stress, Inflammation and Skin Aging" which has confirmed skin both as an immediate stress perceiver and as a target of stress responses. As one of the largest organs of the body along with fascia, the skin plays an important barrier and immune function, by maintaining homeostasis between the external environment and internal tissues.

Cortisol - This is the primary stress hormone, has been known to break down the collagen in your skin, among other things. The more stressed you are, the more cortisol your body produces. Eventually, your skin cells won’t be able to naturally rebuild the elastin and collagen as well as they used to.

2004 Study - Showed the first link between chronic stress and aging. This study showed that telomeres (structures at the ends of chromosomes that shorten with aging) also shorten prematurely in people experiencing long-term psychological stress, in effect, prematurely "aging" the cells. Since then, subsequent studies have confirmed the finding that shortened telomeres are associated with psychological stress.

How stress affects your skin

Your skin is the primary sensing organ for external stressors, for example, heat, cold, pain, and mechanical tension. You have three classes of receptors:

  1. Thermoreceptors - heat and cold,
  2. Nociceptor - pain,
  3. Mechanoreceptors - mechanical changes.

These receptors are responsible for transmitting external signals to the spinal cord, and then onwards to the brain. The skin's sensory fibers also convey changes in temperature, pH, and inflammatory mediators to the central nervous system (CNS). The brain responds to these signals, which in turn influence the stress responses in the skin.

/ THE BRAIN / secretes:
NT's - neurotrophins are capable of signaling particular cells to survive, differentiate, or grow.
SP - Substance P is a peptide composed of a chain of 11 amino acid residues, It is a neuropeptide, acting as a neurotransmitter and as a neuromodulator.
Prolactin - is a protein best known for its role in enabling mammals, usually females, to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans.

Hypothalamus secretes:
CRH corticotropin-releasing hormone, stimulating its growth and its secretion of corticosteroids (cortisone-like hormones)

    Pituitary Gland secretes:
    POMC peptides proopiomelanocortin - The peptides attach (bind) to one of several proteins in different regions of the body, and this binding triggers signaling pathways that control many important functions.
    ACTH - adrenocorticotropin stimulates the release of a hormone called cortisol. This hormone helps maintain blood sugar levels, protects the body from stress, and stops inflammation.

      The Adrenal Gland secretes:
      GC - Glucocorticoids are steroid hormones with powerful anti-inflammatory effects produced by the human body.
      Catecholamines - The adrenal glands send catecholamines into your blood when you're physically or emotionally stressed.

        / THE SKIN /
        Sebaceous Gland produces:
        CRH corticotropin-releasing hormone, stimulating its growth and its secretion of corticosteroids (cortisone-like hormones).
        Prolactin - induced by psychological stress.

        Skin Nerve endings Secrete:
        SP Substance P is a peptide composed of a chain of 11 amino acid residues, It is a neuropeptide, acting as a neurotransmitter and as a neuromodulator.
        Catecholamines are released into your blood when you're physically or emotionally stressed.

          Epidermal keratinocytes and melanocytes secrete:
          CRH - corticotropin-releasing hormone, stimulating its growth and its secretion of corticosteroids (cortisone-like hormones).
          ACTH adrenocorticotropin - stimulates the release of a hormone called cortisol. This hormone helps maintain blood sugar levels, protects the body from stress, and stops inflammation.
          NT's - neurotrophins are capable of signaling particular cells to survive, differentiate, or grow.
          Prolactin induced by psychological stress.
          Catecholamines - are released into your blood when you're physically or emotionally stressed.

            Dermal fibroblasts secrete:
            ACTH - adrenocorticotropin stimulates the release of a hormone called cortisol. This hormone helps maintain blood sugar levels, protects the body from stress, and stops (suppresses) inflammation.
            Cortisol - is a steroid hormone that regulates a wide range of processes throughout the body, including metabolism and the immune response. It also has a very important role in helping the body respond to stress.
            NT's - neurotrophins are capable of signaling particular cells to survive, differentiate, or grow.
            Prolactin induced by psychological stress.

              Mast cells secrete:
              CRH - corticotropin-releasing hormone and possess receptors for:
              CRH - corticotropin-releasing hormone, stimulating its growth and its secretion of corticosteroids (cortisone-like hormones).
              Cortisol - is a steroid hormone that regulates a wide range of processes throughout the body, including metabolism and the immune response. It also has a very important role in helping the body respond to stress.
              NT's - neurotrophins are capable of signaling particular cells to survive, differentiate, or grow.
              SP - Substance P is a peptide composed of a chain of 11 amino acid residues, It is a neuropeptide, acting as a neurotransmitter and as a neuromodulator.
              Prolactin induced by psychological stress.

                Stress is known to affect various diseases and conditions, like asthma, arthritis, migraines, and multiple sclerosis. Neuroinflammatory skin conditions can be triggered or aggravated by stress. 

                Skin mast cells are a central player of the skin stress responses, acting like “central switchboards” of neurogenic inflammation. In the skin, they are located near Substance P and nerve endings and blood vessels, where they are the first-line defense of the immune system.

                / Psoriasis /

                Psoriasis is a chronic skin inflammatory disease, affecting about 2% of populations worldwide. It is characterized by an overproliferation of keratinocytes and inflammation, which leads to the enlargement of a tissue (skin) caused by an increase in the reproduction rate of its cells, a hallmark of lesional psoriatic skin. These plaques are most seen on the elbows, knees, and scalp.  Recent research has revealed parts of the manner of development of a disease and the intricate crosstalk between nerves, immune system, endocrine system, and skin cells, there is still no cure for psoriasis. Stress is both a consequence of living with psoriasis and a cause for psoriasis exacerbation. Stress leads to inflammatory skin response.

                / Acne /

                Acne vulgaris is a very common skin disease affecting a majority of the population at some point in their lives. It affects the skin including the face, the upper part of the chest, and the back. The development of a disease is characterized by increased colonization of P. acne bacteria, increased sebum production from the sebaceous glands, inflammation, and hyper-keratinization - when skin cells of the follicle become cohesive and don't shed normally on the surface of the skin. Stress has long been suspected to induce acne flares by clinical experiences and anecdotal observations it was confirmed in 2003 by a well-controlled study. In a student examination stress study, increased acne severity is significantly associated with stress levels.

                / Atopic Dermatitis /

                Atopic dermatitis is a chronic and relapsing inflammatory skin disease often associated with eczema and itch. A complex interaction of genetic, environmental, and immunological factors is manifested in dermatitis. A defect in the skin barrier function is a key feature of dermatitis.

                Environmental factors such as allergens or microbial organisms are critical triggers or complications in the disease. Similar to psoriasis, dermatitis symptoms and psychological stress seem to form a vicious cycle. Dermatitis patients have been reported to have anxiety and depression, while psychological stress, in turn, can exacerbate dermatitis pathology. Stress can impact dermatitis symptoms, stress can negatively affect the skin’s permeability barrier function and homeostasis. In dermatitis patients, barrier dysfunction could lead to increased sensitization to allergens and microbial organisms increased transepidermal water loss and a lower threshold for the itch. 

                Stress also contributes to the immune and inflammation dysfunction in dermatitis patients. It has been discovered that oxytocin (OXT), a neuropeptide playing a major role in behavior regulation, is down-regulated in dermatitis skin. Both oxytocin and its receptor are detected in keratinocytes and fibroblasts, and it affects cell proliferation, inflammatory cytokines release and oxidative stress responses. 

                Skin mast cells are activated by stress, and in turn, they also produce stress hormones and inflammatory factors. This could lead to a vicious cycle of stress-induced inflammatory events. Mast cells have been implicated in numerous skin diseases including acne, atopic dermatitis, psoriasis, and pruritus. 

                Barrier Repair Function and Stress

                The stratum corneum (SC) plays important barrier functions by regulating epidermal permeability and homeostasis. This protein/lipid barrier creates a surface seal essential for the maintenance of hydration and protection against microbial infection. Disruption of the skin barrier function can lead to flaky or dry skin. Alternation of the lipids composition has also been linked to skin conditions such as - atopic dermatitis and psoriasis.

                Stress can cause detrimental physiological and functional consequences in the skin. A study about insomnia the authors discovered that stress can significantly impair epidermal proliferation and differentiation, decrease the size and density of corneodesmosomes (the main intercellular adhesive structures in the stratum corneum) and decrease lipid synthesis and lamellar body production in keratinocytes in the skin. It also confirmed the critical role of lipids because the topical application of lipids including ceramides and free fatty acids can restore barrier function and skin integrity.

                One of the skin’s major functions is physical protection and wound repair. Wound healing is an intricate process that involves resident skin cells, skin extracellular matrix, and systematic factors. It is divided into three major yet overlapping phases:
                1. Inflammation - cytokines, and chemokines protect against infection, attract phagocytes (a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles) and recruit fibroblasts (a cell that synthesizes the extracellular matrix ECM and collagen)
                2. Proliferation - new granulation tissue is rebuilt with collagen, blood vessel, and other extracellular matrix proteins.
                3. Remodeling - collagen is remodeled and realigned and apoptosis (a form of programmed cell death) remove unnecessary cells, which may take weeks or months.

                Chronic systemic corticosteroids have a negative impact on all three phases of wound healing, analysis has also concluded that stress is associated with impaired healing or dysregulation of healing biomarkers.

                Chronic Stress and Skin Damage

                Chronic stress usually suppresses immunoprotection, increases susceptibility to infections, and exacerbates some allergic and inflammatory diseases. This is due to altered stress responses after repeated or prolonged stress termed stress habituation. Aging also has a negative effect.

                Skin aging is characterized by the formation of lines and wrinkles, increased pigmentation, loss of elasticity and firmness, and dull skin. It is a consequence of both intrinsic factors and extrinsic factors. UV irradiation (photoaging) is one of the major extrinsic stressors responsible for premature skin aging.

                Epinephrine, norepinephrine, and cortisol - stress hormones have been found to increase DNA damage, interfere with DNA repair, and alter the regulation of the cell cycle. Stress can have a major impact on skin aging through the Reactive oxygen species (ROS) pathway.

                Smoking and air pollution are critical chronic stressors that impact skin aging significantly. ROS production leads to dermal matrix breakdown and wrinkle formation. Air born particles exposure from traffic is associated with a significant increase in pigment spots and facial wrinkles. ROS production is the major underlying mechanism inducing the depletion of Vitamin E and lipid peroxidation, as well as increasing matrix metalloproteinase (MMP) production and collagen degradation, leading to the formation of wrinkles.

                Telomere shortening has emerged as another possible cellular mechanism linking chronic psychological stress and aging. Telomeres are DNA repeats at the ends of chromosomes and it shortens with each cell division, eventually leading to replicative senescence and premature cellular aging. Various chronic stress situations have been associated with shorter telomere length, including caregiving for a sick child with chronic conditions or elderly dementia patients, major depression, childhood adversity, and exposure to intimate partner violence.

                A recent study established the negative effect of sleep deprivation on skin aging. It was found that poor quality sleepers showed increased signs of intrinsic skin aging including fine lines, uneven pigmentation and reduced elasticity. They also recover much slower after skin barrier disruption. You can read my blog "Sleeping Beauty" here, and then get a good night's sleep!

                Until next time..

                be human, be kind, be you

                  

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                / REFERENCES /

                Brain-Skin Connection: Stress, Inflammation and Skin Aging -Ying Chen and John Lyga.
                https://www.ncbi.nlm.nih.gov/pubmed/24853682

                Does poor sleep quality affect skin aging?
                https://www.ncbi.nlm.nih.gov/pubmed/25266053

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