Immunomodulators in cosmetics

Usually, immunomodulators are understood as substances that in therapeutic doses enhance or restore the functions of various links of the immune system. Substances that suppress specific stages of the immune response are called immunosuppressors, and those that have a targeted, "point" effect, affect the secretion of certain humoral factors or the functions of certain cells - immunocorrectors. It must be recognized that so far no immunotropic drug has such a selective effect that it can be called an immunocorrector.

Currently, in medicine, immunomodulators in combination with antibacterial therapy are used in the treatment of chronic sluggish inflammatory and infectious diseases. It is permissible to use immunomodulators as monotherapy to speed up recovery after severe diseases, for preventive purposes in the autumn-winter period if there is a history of frequent respiratory infections. Immunosuppressants, such as cytostatics or glucocorticoids, are used to treat allergic and autoimmune diseases, as well as in tissue and organ transplantation operations.

The topic of using immunomodulators to treat infectious diseases is very interesting, but let's get back to the skin. How effective can immunomodulators be in cosmetology? Can cosmetics be used to increase the functional activity of the skin's immune system? Strictly speaking, it is impossible. By definition, cosmetics are intended to decorate, cleanse and protect the skin, but they have no right to interfere with its physiology. However, recently, a large class of cosmetics has appeared, the so-called cosmeceuticals, which are designed specifically to affect skin cells and which, accordingly, can also affect its physiology. Therefore, before saying "yes" or "no" to immunomodulators in cosmetology, it is necessary to understand what we can actually expect from them, what is the mechanism of their action and whether there is a risk in using them.

Immunity and barrier

The skin is such a perfect barrier that pathogens on its surface do not cause any harm to the body. Problems begin only when the skin barrier system is damaged, the pathogen penetrates the stratum corneum, and the cells of the immune system are involved in its destruction. The destruction of the pathogen by the cells of the immune system is somewhat worse adjusted than the work of the barrier system, and often leads to the development of pathological processes and tissue damage.

The skin can be compared to a state that has erected barriers to unwanted immigrants, sent its best forces to strengthen the borders, but was unable to provide a sufficiently effective system to combat those who managed to enter the country. Therefore, as soon as law enforcement agencies receive information about illegal immigrants, the first thing they do is send a team to find a breach in the defense and eliminate it. The functions of the patrol, raising the alarm when violators appear, are performed in the skin by Langerhans cells, which are the most common target for cosmetics with immunomodulatory action.

The vast majority of immunomodulators used in cosmetics are macrophage activators (Langerhans cells are close relatives of tissue macrophages, as they also originate from monocytes). Although there are a number of substances among immunomodulators that affect lymphocytes, they are not used in cosmetology. Firstly, because almost all of them are medicinal preparations, and secondly, because there are few lymphocytes in the epidermis (these are mainly memory T cells that store information about antigens that have already penetrated the skin). However, since all cells of the immune system are closely interconnected, activation of macrophages cannot but affect other cells - lymphocytes, neutrophils, basophils. The immune system is like a web that all starts moving regardless of where exactly the fly got entangled.

Types of immunomodulators

• Whey, melatonin and other immunomodulators

In addition to polysaccharides - macrophage activators, other immunomodulators are also used in cosmetology. Most of them are substances whose immunomodulatory activity has been discovered in vitro or animal experiments, but has not yet been tested in clinical trials. They are used in cosmetics because either their harmlessness is beyond doubt, or they already have a long history of use as cosmetic ingredients and have, in addition to immunomodulatory, other useful properties. Such substances include whey, bromelain, carnosine, melatonin and some others. Most of them accelerate wound healing and have an anti-inflammatory effect.

• Whey

Whey has been used in cosmetics since time immemorial, so its safety can be considered proven. Biological activity is mainly possessed by the low-molecular fraction of whey proteins, which contains amino acids, growth factors and immunoglobulins. It has been shown that in vitro, the low-molecular fraction of whey proteins stimulates the division of human and animal lymphocyte cultures, which indicates that it has an immunomodulatory effect. Whey contains the amino acid glutamylcysteine, which is necessary for the synthesis of glutathione, one of the main enzymatic antioxidants. Experiments show that glutamylcysteine improves the functioning of immune system cells, increasing the effectiveness of the fight against infections. It is assumed that this occurs due to the fact that glutathione protects immune system cells from oxidative stress.

• Melatonin

Melatonin is a hormone produced by the pituitary gland. The rate of melatonin synthesis depends on the amount of light that hits the retina during the day.

It is assumed that it plays an important role in the regulation of sleep and wakefulness, affects mood (it is believed that insufficient production of melatonin in the autumn-winter period leads to the development of seasonal depression). In addition, this small lipophilic (fat-soluble) molecule exhibits pronounced antioxidant properties. Due to its lipophilicity and small size, melatonin easily penetrates into cell membranes and into the lipid structures of the stratum corneum, protecting them from peroxidation. Recently, melatonin has attracted great interest from researchers as an endocrine immunomodulator, playing the role of the main link between the nervous and immune systems.

• Carnosine

Carnosine is a dipeptide containing the amino acid histidine. It is found in many tissues, primarily in muscle tissue. Carnosine has strong antioxidant properties, which has attracted the attention of cosmetics and food additives manufacturers. In addition, carnosine is a neurotransmitter (a transmitter of nerve impulses in the nervous system), affects the activity of a number of enzymes and binds heavy metal ions, reducing their toxic effects. Recently, the immunomodulatory and wound-healing properties of carnosine have been actively studied.

• Bromelain

Bromelain is an enzymatic fraction of pineapple extract, which contains a number of proteinases - enzymes that dissolve proteins. As a result, it is used as a soft exfoliating agent in cosmetology (enzyme peeling). Food supplements based on bromelain are no less popular. They have anti-inflammatory, fibrinolytic, antihypertensive effects. No side effects have been identified when using bromelain. Bromelain is used in alternative medicine to treat sore throats, bronchitis, sinusitis, thrombophlebitis, and as a means of improving the absorption of drugs such as antibiotics. Recently, it has been found that bromelain enhances the cytotoxic effect of monocytes against tumor cells, the production of interleukins IL-2p IL-6, IL-8, TNF. When applied locally, bromelain accelerates the cleansing of wounds and accelerates their healing.

• Cellular and tissue preparations

A number of cosmetic companies use tissue extracts and cellular preparations (thymus and embryonic tissue extracts) as immunomodulators. They serve as sources of cytokines - regulatory molecules that affect the functions of the immune system (the method is based on the hypothesis that the skin will take what it needs from the set of biologically active substances offered to it).

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