Epidermal changes during UVB phototherapy assessed by multiphoton laser tomography

BACKGROUND

Multiphoton laser tomography (MPT) is a non-invasive technique that allows imaging of skin in vivo with very high spatial resolution and contrast. Previous work of our group has demonstrated that known morphological changes due to erythematogenic ultraviolet B (UVB) irradiation may be imaged in vivo by MPT. The present work investigated if morphological skin changes known from experimental erythematogenic UVB irradiation are also demonstrable in the course of a standard phototherapy regime that implies suberythematogenic doses of narrow band UVB.

METHODS

Sixteen patients with psoriasis vulgaris receiving a narrow band phototherapy were included. A test field and a light-protected control field were measured with the multiphoton tomograph DermaInspect^® at four time points: at baseline, the next day, after 3 days and at the day of the last exposure.

RESULTS

In the course of the UVB phototherapy, spongiosis and pleomorphy as parameters of inflammation and cellular damage did not show significant changes. By contrast, an adaptive skin reaction with significant changes of keratosis and pigmentation was observed.

CONCLUSION

MPT is a suitable technique for the investigation of qualitative and quantitative skin changes after UVB irradiation. After suberythematogenic UVB irradiation, photoadaptive skin changes, but no cellular damage can be observed with MPT.

Acute UVB-induced epidermal changes assessed by multiphoton laser tomography

BACKGROUND

In vivo multiphoton tomography (MPT) of human skin has become a valuable tool for non-invasive examination of morphological and biophysical skin properties and their alterations. So far, skin changes after UVB irradiation were mainly evaluated clinically and histologically. The present study aimed at non-invasive imaging of histological changes during acute UVB irradiation by multiphoton laser tomography.

METHODS

In 10 volunteers, five areas were irradiated once with an erythematous UVB dose. Multiphoton measurements were performed four times, i.e. before irradiation (baseline), and 24, 48 and 72 h after irradiation, respectively. The data were evaluated for changes of epidermal pleomorphy, spongiosis, pigmentation and thickness.

RESULTS

The four parameters were altered significantly by acute UVB irradiation, i.e. epidermal pleomorphy, spongiosis, pigmentation and thickness increased within 72 h after irradiation.

CONCLUSION

Thus, the study has shown that typical epidermal changes induced by acute UVB irradiation can be evaluated by MPT.

Actinic damage and its treatments

Over the last decades, there has been a dramatic increase of skin tumour incidence that results from actinic damage. This increase is mainly due to the current demographic development, but also due to a change in spare time habits. Thus, the treatment and prevention of light induced skin tumours is gaining interest, but also the treatment of photoaged skin. This review will focus on 1) the basic principles of actinic damage including carcinogenesis; 2) treatment options for photoaged skin and 3) an overview of current therapy concepts of light induced skin tumours.

RegRand: statistical software for the multiple-baseline design

RegRand (Version 1.0) is Macintosh-based software that enables a researcher to conduct a non-parametric statistical analysis of the data from Koehler and Levin's (1998) recently described regulated randomization single-case multiple-baseline design. Regulated randomization design and analysis principles are reviewed in relation to an educational research application and a step-by-step illustration of them in relation to the RegRand program is presented.