The impact of high-dose narrowband ultraviolet A1 on dermal thickness, collagen and matrix-metalloproteinases in animal model of scleroderma

Biological effects of a new ultraviolet A1 prototype based on light‐emitting diodes on the treatment of localized scleroderma

“…Up to date, only a few murine studies are available using a narrowband UVA 1 light source for the treatment of scleroderma. [ 30,31 ] Karpec and coauthors described the safety and efficacy of 365 nm LED‐based UVA 1 phototherapy in bleomycin‐induced scleroderma in mice, [ 31 ] but the optimum UVA 1 spectrum for scleroderma treatment has not yet been determined and needs to be examined further.…”

Tryptophan photo-product FICZ upregulates AHR/MEK/ERK-mediated MMP1 expression: Implications in anti-fibrotic phototherapy

“…Although UV radiation induces deleterious cell damage by generating DNA photo-products in the nucleus, reactive oxygen species, and metabolizing enzymes such as CYP1A1 and CYP1B1 [29,30], its anti-fibrotic effects are clinically applicable to fibrosing or sclerotic diseases such as scleroderma [10]. It is known that UV inhibits collagen synthesis and promotes its degradation by enhancing the expression of MMPs [5,6,11].…”

“…Given that long-term chronic exposure to ultraviolet (UV) rays leads to a decrease of dermal collagen [9], phototherapy with UVA or UVB has been undertaken for scleroderma with a beneficial outcome [10]. UVA1 radiation increases the expression of MMP1 and À3 in the skin, and decreases type I and III collagen in the skin of a bleomycin-induced mouse model of scleroderma [11]. Similarly, UVB exposure increases the expression of MMPs including MMP1 and MMP3 in human skin [6] and human dermal fibroblasts in vitro [5], but the precise mechanisms behind this are not fully understood.…”

Ultraviolet A1 Phototherapy for Fibrosing Conditions

“…These results are in line with another mouse model study by Karpec and colleagues who investigated in scleroderma patients the impact of high-dose UV-A1 on dermal sclerosis. They could demonstrate that a total dose of 1,200 J/cm 2 does obviously not only prevent worsening of dermal fibrosis but also leads to a decrease of fibrotic skin changes (26). A further study by this working group showed in an animal model employing bleomycin- induced scleroderma that UV-A1 (cumulative doses: 1,200 J/cm 2 and 600 J/cm 2 ) is effective as well safe in the management of scleroderma (27).…”