Comparative studies on the tolerance to photoinduced cutaneous inflammatory reactions by psoralen and rose bengal

Enhanced intradermal delivery of Dragon's blood in biocompatible nanosuspensions hydrogel patch for skin photoprotective effect

Dragon's Blood is a member of the Chinese medicinal herb, having anti-oxygen and anti-inflammatory activity for the photoprotective effect. However, the poor water solubility of raw Dragon's Blood powder has limited its intradermal delivery process. In this study, we evaluated nanosuspensions to enhance intradermal delivery of Dragon's Blood exerting a photoprotective effect. The prepared nanosuspension was added to a composite hydrogel patch matrix for better skin application. In the present research, we used biocompatible materials hyaluronic acid and amino acid surfactants as nanosuspension stabilizers and agar/gelatin/sodium polyacrylate as hydrogel patch matrix. The prepared Dragon's Blood nanosuspension had a particle size of 447.0 ± 48.6 nm. The micro-structures morphology and viscoelasticity characteristics by SEM and rheological testing confirmed a sufficient crosslinked hydrogel network. The skin retention amount of Dragon's Blood nanosuspension was 1.48 times of raw Dragon's Blood powder water suspension, and the skin penetration amount of Dragon's Blood nanosuspension was only about 1/3 of Dragon's Blood DMSO solution. In the UVB-irradiated HaCaT cell phototoxicity model, Dragon's Blood nanosuspension also significantly increased cell viability by about 1 time of the model group and decreased the production of reactive oxygen species about 1/2 times of model group. In vivo safety and efficiency evaluation experiment illustrated that DB-NS hydrogel patch processes have favorable safety and photoprotective effect with no skin irritancy and phototoxicity. Furthermore, DB-NS and DB-NS hydrogel patches could protect skin from UVA and UVB irritating skin reactions. Overall, our study of the combined use of biocompatible and biodegradable materials as excipients of nanosuspension and hydrogel patch could be used as an effective additive of Intradermal delivery and skin photoprotection.

Orally administered polypodium leucotomos extract decreases psoralen-UVA–induced phototoxicity, pigmentation, and damage of human skin

BACKGROUND

The use of psoralen-UVA (PUVA) in patients of skin phototype I to II is limited by side effects of acute phototoxicity and possible long-term carcinogenesis.

OBJECTIVE

We sought to assess oral Polypodium leucotomos (PL) extract in decreasing PUVA-induced phototoxicity of human skin on a clinical and histologic level.

METHODS

A total of 10 healthy patients with skin phototypes II to III were exposed to PUVA alone (using 0.6 mg/kg oral 8-methoxypsoralen) and to PUVA with 7.5 mg/kg of oral PL.

RESULTS

Clinically, phototoxicity was always lower in PL-treated skin after 48 to 72 hours (P<.005), and pigmentation was also reduced 4 months later. Histologically, PL-treated skin showed a significant numeric reduction of sunburn cells (P=.05), preservation of Langerhans cells (P< or =.01), decrease of tryptase-positive mast cell infiltration (P<.05), and decrease of vasodilation (P< or =.01). No differences were found in Ki-67+ proliferating cells.

CONCLUSIONS

PL is an effective chemophotoprotector against PUVA-induced skin phototoxicity and leads to substantial benefits of skin protection against damaging effects of PUVA as evidenced by histology.

8-Methoxypsoralen and long-wave ultraviolet A inhibit the release of proinflammatory mediators and cytokines from human Fc epsilon RI+ cells: an in vitro study

The in vitro effects of 8-MOP (concentrations of 20, 100 and 500 ng/ml) alone or in combination with UVA on mediator release from human basophils and skin mast cells (HSMC), activated with immunological and non-immunological stimuli, were investigated. With respect to basophils activated with anti-IgE serum, the results of this study show that: (i) 8-MOP alone inhibits histamine, LTC(4), IL-4 and IL-13 release concentration dependently with a maximal effect at 500 ng/ml (a concentration not reached in vivo); and (ii) UVA irradiation (5 J/cm(2)), after 8-MOP incubation, enhances this inhibitory effect on all released mediators, but for IL-4 and IL-13 the percentage inhibition is also significant for the 8-MOP concentrations (20-100 ng/ml) employed in vivo during PUVA treatment. Moreover, histamine release from basophils activated with non-immunological stimuli (FMLP and A23187) is inhibited by 8-MOP, alone or in combination with UVA. With respect to the HSMC activated with anti-IgE serum, the results show that: (i) 8-MOP alone reduces histamine release concentration dependently; and (ii) this inhibitory effect is enhanced by UVA irradiation (5 J/cm(2)). Histamine release from HSMC activated with A23187 is not modified either by 8-MOP alone or by 8-MOP plus UVA.

The role of PUVA in the treatment of psoriasis. Photobiology issues related to skin cancer incidence

Photochemotherapy with methoxsalen (8-methoxypsoralen) and long wavelength ultraviolet (UV) radiation (referred to as 'PUVA' for psoralen plus UVA) is commonly used to treat psoriasis and vitiligo. These vastly different diseases respond to the therapy by different mechanisms even though the immediate effects of the therapy--the photomodification of cellular biomolecules--is the same for each. Because psoriasis is not cured by PUVA, patients receive many treatments over their lifetime and have a significantly increased risk for the development of skin cancers (primarily squamous cell carcinomas). In this article the basic aspects of psoralen photobiology are reviewed briefly. Several recent studies describing the incidence of skin cancer in UVA treated psoriasis cohorts are comparatively reviewed. In addition the impact of the analysis of mutations in the tumor suppressor gene, p53, are summarized. An unexpected mutation spectrum (very few PUVA type T-->A transversions and frequent UVB solar signature C-->T transitions) suggest that effects other than direct DNA photoadduct formation may be at play. These analyses suggest that it may be possible to improve the therapeutic efficacy of PUVA by a careful evaluation of the mode of delivery. In this review the science behind PUVA is summarized. In addition, the incidence of skin cancer as a long term consequence of repeated treatments is surveyed. To relate clinical observations to molecular events, the nature of p53 mutations found in skin cancers from psoriasis patients is also analyzed. Finally some suggestions for improving the delivery of PUVA therapy are presented.