INTRODUCTION
Androgenetic alopecia (AGA) is a chronic form of hair loss characterized by the miniaturization of hair follicles. There are different prescription and over-the-counter treatments for AGA, which have various advantages and drawbacks, but the search for the ideal AGA treatment continues.1 Cold atmospheric pressure (physical) plasma (CAP), a partially ionized gas, is an emerging treatment modality with expanding use in dermatology.2 There is a vast body of literature exploring the effects of CAP in cell cultures and animal models. It is shown to have a deleterious effect on bacteria and fungi.3 It also selectively causes cell death in malignant cell lines in vitro.4 Other experiments indicate the ability of CAP to induce stem cell differentiation.5 This important effect has been described in various cell types, including adipose derived stem cells,6 and neural stem cells.7 Clinical dermatological use of CAP originated in the treatment of chronic ulcers, based on its antiseptic effects.8 Small pilot studies showed efficacy of CAP treating actinic keratosis and warts.9,10,11
Minoxidil, one of the most established treatment modalities for AGA, may induce hair follicle stem cell differentiation and hair growth via triggering cellular calcium influx.12 As CAP has also been shown to induce cellular calcium influx in vitro,13 one can hypothesize that it may be able to improve AGA by inducing hair follicle stem cell differentiation based on its similar effect on other stem cell populations, and specifically via triggering cellular calcium influx. We are not aware of any prior reports describing the use of CAP to induce hair growth in humans, but a recent rat model based study showed that CAP treatment using a nitrogen-CAP jet-type device increased hair diameter.14 If proven to be safe and effective, CAP may offer an alternative for the treatment of AGA.
CAP is used to treat living tissues in two main ways. Direct CAP treatment is when the partly ionized gas is created directly on the treated surface or delivered to the surface immediately by a gas jet stream. Indirect CAP treatment is a process when a liquid is exposed to CAP and the created mixture is delivered to a cell culture or living tissues. Plasma is a complex ionized gas, which contains various reactive species and charged particles. Although applying direct CAP to the surface of human skin was shown to be safe and tolerable in different settings,15,16 the depth of penetration of direct CAP treatment is limited,17 and may not be sufficient to reach the hair follicles, especially on thick human scalp skin. Currently available methods of delivering direct CAP treatment are also time-consuming and impractical
Minoxidil, one of the most established treatment modalities for AGA, may induce hair follicle stem cell differentiation and hair growth via triggering cellular calcium influx.12 As CAP has also been shown to induce cellular calcium influx in vitro,13 one can hypothesize that it may be able to improve AGA by inducing hair follicle stem cell differentiation based on its similar effect on other stem cell populations, and specifically via triggering cellular calcium influx. We are not aware of any prior reports describing the use of CAP to induce hair growth in humans, but a recent rat model based study showed that CAP treatment using a nitrogen-CAP jet-type device increased hair diameter.14 If proven to be safe and effective, CAP may offer an alternative for the treatment of AGA.
CAP is used to treat living tissues in two main ways. Direct CAP treatment is when the partly ionized gas is created directly on the treated surface or delivered to the surface immediately by a gas jet stream. Indirect CAP treatment is a process when a liquid is exposed to CAP and the created mixture is delivered to a cell culture or living tissues. Plasma is a complex ionized gas, which contains various reactive species and charged particles. Although applying direct CAP to the surface of human skin was shown to be safe and tolerable in different settings,15,16 the depth of penetration of direct CAP treatment is limited,17 and may not be sufficient to reach the hair follicles, especially on thick human scalp skin. Currently available methods of delivering direct CAP treatment are also time-consuming and impractical
