In vitro and ex vivo protoporphyrin IX expression induced by 5-aminolevulinic acid in human pilosebaceous unit

Comparison of protoporphyrin IX accumulation and destruction during methylaminolevulinate photodynamic therapy of skin tumours located at acral and nonacral sites

“…Firstly, the significant reduction ( P < 0·01) in the level of PpIX attained following the application of the topical prodrug in acral skin was probably due to limited prodrug penetration through the stratum corneum into the diseased cells below. This reduction in PpIX accumulation may be a result of a thicker stratum corneum in acral skin, 30 which has previously been demonstrated to show a weak negative correlation with PpIX fluorescence, 31 or alternatively the increased number of pilosebaceous units of the head may improve PpIX accumulation within nonacral skin regions 32 . Secondly, acral AK lesions were observed to undergo a statistically significantly lower level ( P < 0·05) of PpIX photobleaching during light irradiation.…”

“…This reduction in PpIX accumulation may be a result of a thicker stratum corneum in acral skin, 30 which has previously been demonstrated to show a weak negative correlation with PpIX fluorescence, 31 or alternatively the increased number of pilosebaceous units of the head may improve PpIX accumulation within nonacral skin regions. 32 Secondly, acral AK lesions were observed to undergo a statistically significantly lower level (P < 0AE05) of PpIX photobleaching during light irradiation. Due to the established relationship between PpIX photobleaching and the subsequent cellular damage ⁄clinical outcome observed, 24,25,27,28 this reduction in PpIX photobleaching within acral AK lesions suggests lower levels of cellular damage ⁄death and therefore an ultimately poorer clinical outcome as reported here.…”

The efficacy and tolerability of 5‐aminolevulinic acid 5% thermosetting gel photodynamic therapy (PDT) in the treatment of mild‐to‐moderate acne vulgaris. A two‐center, prospective assessor‐blinded, proof‐of‐concept study

“…PDT involves the application of a photosensitizing chemical, 5‐aminolevulinic acid (5‐ALA) which, when exposed to various lights, results in excitation of the photosensitizer (protoporphyrin, PpIX) and consequent production of a reactive oxygen species that leads to cytotoxicity . PpIX is a photosensitizer that accumulates not only in the epidermal cells but also in the pilosebaceous units . When intense visible light is delivered on the ALA‐treated skin, PpIX is excited into a triplet state, which reacts with oxygen to produce singlet oxygen, causing membrane damage and cell destruction.…”

“…10 PpIX is a photosensitizer that accumulates not only in the epidermal cells but also in the pilosebaceous units. 11 When intense visible light is delivered on the ALAtreated skin, PpIX is excited into a triplet state, which reacts with oxygen to produce singlet oxygen, causing membrane damage and cell destruction. ALA is taken up selectively in sebaceous glands and is processed to porphyrins.…”

Photodynamic therapy for severe facial acne vulgaris with 5% 5‐aminolevulinic acid vs 10% 5‐aminolevulinic acid: A split‐face randomized controlled study

“…Nodules and severe cysts are deeper than papules and pustules. The penetration depth of the red light is approximately 6 mm, and PpIX is mainly found in the epidermis and pilosebaceous gland, but little is found in the dermis . There is a possibility that neither the red light nor PpIX can reach the bottom of the nodules and large cysts in the two groups.…”