Ultraviolet A1 phototherapy utilizing ultraviolet light-emitting diodes and a short wavelength cutoff filter

Ultraviolet (UV) A1 phototherapy selectively uses longer UVA1 wavelengths (340−400 nm), and does not include the shorter UVA2 (320−340 nm) or UVB (290−320 that cause erythema reactions. Several studies in which a metal-halide lamp was used as light source demonstrated efficacy of for various diseases T cells infiltrate dermis induce excessive collagen accumulation, such atopic dermatitis [[1]Morita A. Werfel T. Stege H. Ahrens C. Karmann K. Grewe M. Grether-Beck S. Ruzicka Kapp Klotz L.O. Sies Krutmann J. Evidence singlet oxygen-induced human helper cell apoptosis is basic mechanism ultraviolet-A radiation phototherapy.J. Exp. Med. 1997; 186: 1763-1768Crossref PubMed Scopus (237) Google Scholar], T-cell lymphoma [[2]Plettenberg J.K.H. Megahed Hosokawa Y. Tsuji Morita (340-400 cutaneous lymphoma.J. Am. Acad. Dermatol. 2000; 43: 881Abstract Full Text PDF (8) systemic sclerosis [[3]Morita Kobayashi Isomura I. scleroderma sclerosis.J. 670-674Abstract (108) Scholar]. Although lamps are commonly therapy due to their high intensity, they efficient because broad spectrum (200−500 require 3 filters remove unnecessary wavelengths. The luminous efficiency light-emitting diodes (LEDs) recently remarkably improved, reaching level can be phototherapy. wavelength specificity within range, however, has been clarified. Therefore, we investigated characteristics AlGaN InGaN system LEDs develop more effective delivery system. Normal dermal fibroblasts were irradiated with monochromatic ranging from 355 nm 395 5-nm 10-nm increments (Fig. 1a, Table 1a) using UV-LEDs (Imac, Shiga, Japan) incubated 48 h 5% CO2 at 37 °C humidified atmosphere. relative spectrums irradiances irradiation measured spectral radiometer (USR-45DA, Ushio Inc, Tokyo, Japan; Fig. 1a). After incubation, matrix metalloproteinase-1 (MMP1) transforming growth factor-beta receptor type 2 (TGFBR2) mRNA expression levels real-time polymerase chain reaction.Table 1Irradiation conditions an experiment (a) normal (b) neonatal epidermal melanocytes.a)Dose [J/cm2]Irradiation distance [mm]Irradiance [mW/cm2]Irradiation time [h:m:s]Sham irradiation0––0:00:00355nm15201.82:18:53360nm15202.81:29:17365nm1520250:10:00375nm1520100:25:00385nm1520590:04:14395nm1520590:04:14b)Dose [m:s]Sham irradiation0––0:00Filter (-)1530111.42:15A filter (+)153085.82:55B (+)153097.22:34 Open table new tab MMP1 upregulated all 1b left), significantly 360 nm, 365 375 385 irradiation. peak ratio approximately 7.7. On other hand, TGFBR2 downregulated right), significant downregulation observed nm. around Our findings indicate most induces fragmentation activates fibroblast proliferation. therapeutic effect, but it also causes immediate pigment darkening (IPD) deleterious effect. IPD dull grayish-brown enhancement during immediately after UVA begins disappear 5–10 min generally disappears several hours. Irradiation over threshold develops leads persistent even 24 may continue weeks. interfere treatment completion. action 340 [[4]Irwin Barnes Veres D. Kaidbey An ultraviolet Spectrum darkening.Photochem. Photobiol. 1993; 57: 504-507Crossref (37) In effort decrease IPD, Neonatal melanocytes short cutoff (A filter, B filter) no 1c, 1b). irradiation, atmosphere tyrosinase by reaction. addition, 7 days melanin evaluated measuring absorbance 405 plate reader (SPECTRA MAX 340, Molecular Devices, San Jose, CA). increased both absorbance. Melanin production suppressed A 1d). conclusion, present in-vitro 365-nm UV-LED promising phototherapy, use suppress Further vivo needed skin penetration critical factor This work supported Grant-in-Aid Scientific Research 17H04242 (AM) research grant Nagoya City University .