PEER-REVIEW | DERMATOLOGY |
Table 6 Treatment effectiveness FREQUENCY
PERCENT
Yes 19 61.3 No 7 22.6 Maybe 4 16.1 Total 30 100
Patient’s assessment of SBRR-MAL-PDT clinical effectiveness damage as described in all PDT procedures9 . Molecular
oxygen is the essential ‘fuel’ to support PDT reactions during light irradiation. Providing a constant supply for the generation of highly reactive oxygen species is essential to the overall efficacy of PDT procedures. Should O2
not be available in sufficient quantities to
support PDT reactions during the whole duration of light irradiation, PDT effectiveness will inevitably be affected. MAL is not a photosensitizer by itself. It represents a that will eventually generate the active
pro-drug7,10
photosensitizer through a metabolic conversion within specific cells10–12
. . MAL is the methyl ester of 5-ALA and has
been shown to penetrate more easily through the skin barrier, being relatively more selective in concentrating within pilo-sebaceous units13
Laser, IPPL, and LED sources can generate suitable
wavelengths to be absorbed by porphyrins used in PDT procedures. Each light source can therefore produce an efficient PDT reaction within target tissues. LED sources have the advantage to cover relatively large areas with an almost uniform irradiation density.
Clinical studies SW-SE acne-PDT has been widely performed, inducing significant improvements in clinical manifestations of acne vulgaris. Many studies have been published providing useful information about the effectiveness, tolerability, and side effects of different PDT strategies. MAL-PDT has been proven to be an effective treatment for inflammatory acne vulgaris even if occasionally associated with severe pain during irradiation and potentially significant post-treatment side-effects14 In a placebo-controlled randomised trial focusing on
.
conventional (SW-SE) red light (635 nm)-MAL-PDT vs. red light (635 nm)-placebo-PDT to treat moderate-to-severe inflammatory facial acne vulgaris, both effectiveness and tolerability were evaluated. Thirty patients were enrolled in the study. Clinical results confirmed the effectiveness of SW-SE red light MAL-PDT in reducing the number of inflammatory lesions (mean reduction 54%) compared to placebo-PDT (mean reduction 20%) 12 weeks after PDT sessions. It was not a surprise to read that SW-SE red light MAL-PDT was related to more severe pain during treatments. Repeated treatments produced a relative reduction in pain levels15
. In another recent double blind controlled clinical
study on 36 patients, SW-SE red light (635 nm)-MAL-PDT was compared with red light (635 nm) irradiation alone in
30 August/September 2015 |
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patients affected by mild-to-moderate facial acne vulgaris. A standardized concentration of MAL in a cream vehicle was applied on the whole facial skin. Occlusion contact time (OCT) was set at 90 minutes. A non-coherent red light (635 nm) was used as the irradiation source. The authors concluded that both treatment strategies were able to significantly reduce acne severity 10 weeks after each procedure. The SW-SE MAL-PDT group showed a relatively faster clinical response compared to the group exposed to red light alone. SW-SE MAL-PDT was associated with higher pain levels and post-treatment erythema compared to red light irradiation alone16
. A consistent number of clinical studies have focused
their attention on the comparative clinical effects between 5-ALA and MAL as PDT pro-drugs. In a split-face study on 15 patients with facial acne vulgaris, standard concentrations of MAL and 5-ALA were applied on opposite halves of the face. Although no statistically significant differences were found between the two photosensitizers in terms of effectiveness, 5-ALA-PDT led to more prolonged and serious post-treatment side-effects, such as erythema and flaking. Patients evaluated pain as moderate-to-severe during light irradiation on both sides17
. In another recent retrospective multicenter study
performed in 20 Italian dermatologic clinics, SW-SE MAL-PDT was evaluated for different clinical indications including acne vulgaris. The authors of the study demonstrated a consistent reduction (75%) in clinical manifestations of acne vulgaris in 72.8% of the study population17
. According to the analysis of clinical data, acne
severity was The two different
LED wavelengths have already been confirmed by other studies to induce anti-bacterial (blue LED) and anti- inflammatory (red LED) actions.
significantly decreased after the completion of proposed treatment sessions. This finding is consistent with most of the results published in studies discussed in other similar articles16, 17, 19
.
In addition to this, other studies of SW-SE MAL- PDT using red light have
shown a reduction of inflammatory lesions of between 60 and 70% 3 months after the completion of treatment15,20
.
Efficacy and tolerability The results obtained in the present study confirmed the clinical efficacy of a new MAL-PDT protocol sequentially combining blue 415 nm LED (single 8 minute exposure) and red 633 nm LED (two 16 minute exposures) spaced by 20 minute ‘resting intervals’ (SBRR-MAL-PDT). The two different LED wavelengths have already been confirmed by other studies to induce anti-bacterial (blue LED) and anti-inflammatory (red LED) actions19,21
. The sequential
irradiations of two different wavelengths allows a combination of ‘layered’ PDT effects due to the different trans-epidermal penetration depths specific for blue (750 m) and red light (2000 m). The blue LED exposure
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