# Unveiling the Role of Minerals and Trace Elements of Thermal Waters in Skin Health
## 2 Minerals, Trace Elements, and Other Compounds of TSW in Skin Health
### Anions
#### 2.1.3. Bicarbonate  
Balneotherapy in bicarbonate-sulfate-rich spring water improves the healing of patients with contact dermatitis due to their moisturizing and softening action related to the buffer capacity of the bicarbonate anion [65]. Additionally, several studies showed the benefits of bicarbonate TSW in treating inflammatory skin diseases such as atopic dermatitis. Avene TSW is a bicarbonate-rich spring water that has been shown to exert an anti-inflammatory effect on atopic dermatitis and acne. [PERSON] et al. [20] studied two different thermal spring waters (\"Sainte Odile\" and \"Val d'Orb\") from Avene on rat peritoneal mast cell activation, finding that both were able to inhibit histamine and prostaglandin D2 antigen-induced release and also inhibit histamine release triggered by substance P, which could explain their anti-inflammatory and antiallergic properties. The anti-inflammatory effect of Avene TSW has also been shown in a model of human skin explants stimulated by a neurotransmitter (vasoactive intestinal peptide VIP), in which the Avene TSW showed that the percentage and area of dilated vessels stimulated by VIP treatment was significantly reduced when an Avene-TSW-soaked cotton disk was applied on the skin fragments, and a concomitant decrease in TNF-\(\alpha\) release was also observed after the Avene TSW treatment [21]. Additionally, in an in vitro study, Avene TSW significantly inhibited TNF-\(\alpha\)-induced expression of E-selectin and intercellular adhesion molecule 1 (ICAM-1), and through the inhibition of adhesion molecules involving NF-\(\kappa\)B, the ATSW exhibited a regulation of inflammatory parameters, thus minimizing the inflammatory reaction in atopic dermatitis [22]. The antioxidant effect of Avene TSW has also been investigated. In vitro experiments in normal keratinocytes irradiated with ultraviolet-A (UVA) demonstrated that Avene TSW was able to protect cell membranes, genomic DNA, and proteins from UVA-induced oxidative stress [23]. Later research confirmed the antioxidant activity of Avene TSW; [PERSON] et al. [24] compared the effect of culture media supplemented with (a) thermal spa waters (La Roche-Posay, Avene) and (b) two natural mineral drinking waters (Heppinger, Adelholzener) on physiological parameters in HaCaT keratinocytes, concluding that, despite having different compositions, they both efficiently suppressed the induction of a prototypical inflammatory cytokine (IL-6) and the formation of ROS after UVB stimulation. Clinical studies have also demonstrated the anti-inflammatory effects of Avene TSW. Patients suffering from psoriasis and AD were treated with several therapeutical techniques, including spraying with Avene TSW. The decrease in both in the SCORing atopic dermatitis (SCORAD) and psoriasis area severity index (PASI) scores was associated with a significant reduction in IL-8 and _Staphylococcus aureus_ colonization [25]. Patients suffering from acne were treated with a topical application of retinoic acid alone or in association with a water spray used ad libitum; the results showed a significant reduction in scaling, observing an overall tolerance when applying the combined treatment [26]. In addition, two clinical trials evaluated the use of Avene TSW in terms of efficacy and tolerance when used as an adjunctive care in post-procedure skin care with photodynamic therapy in dermal melasma or acne vulgaris and/or actinic keratoses (spraying Avene TSW after the procedure for a week). In both studies, the Avene TSW reduced erythema and pruritis and relieved pain. The studies showed that spraying Avene TSW after photodynamic therapy significantly reduced the short-term adverse effects associated with the procedure. The results obtained showed the smoothing and anti-irritant properties of Avene TSW due to the involvement in the reduction in the sensitivity of cells and the anti-inflammatory effects [27; 28].