UV erythema reducing capacity of mizolastine compared to acetylsalicylic acid or both combined in comparison to indomethacin

Ultraviolet A-1 in Dermatological Diseases

The exposure to ultraviolet radiations and visible light, or phototherapy, is a well-known therapeutic tool available for the treatment of many dermatological disorders. The continuos medical and technological progresses, of the last 50 years, have involved the field of phototherapy, which evolved from UVA and PUVA in its various forms, to the development of narrowband UVB (NB-UVB) and NB-UVB micro-focused phototherapies. Further advances in technology have now permitted the introduction of a new device emitting UVA-1 radiations.

Delayed ultraviolet erythema not suppressed by oral prednisolone: a randomized crossover study

BACKGROUND

The anti-inflammatory potency of topical dermatological corticosteroids in suppressing ultraviolet (UV) erythema is routinely measured. No such model exists to assess the potency of systemically administered steroids.

OBJECTIVE

To determine whether or not suppression of delayed UV erythema by a systemic corticosteroid could provide a useful model for assessing the anti-inflammatory potency of systemic corticosteroids.

METHODS

We conducted a randomized, placebo-controlled, patient and assessor blinded, crossover study of oral prednisolone effects on the delayed UV-induced erythemal response in normal subjects. Six healthy volunteers were phototested with a xenon arc monochromator and then dosed with 30 mg of oral prednisolone or matching placebo daily for 4 days. Repeat phototesting was performed on the 4th day of dosing. The minimal erythema dose (MED) was assessed immediately after test UV doses were administered and 24 h later. After a 2-week washout period, the dosing and testing were repeated in a crossover fashion.

RESULTS

A suppression index (SI) [1/(baseline MED value divided by on prednisolone/placebo value)] allowed comparison of the degree of suppression on and off prednisolone. Oral prednisolone did not significantly suppress the threshold UV erythema response (MED). We may have missed small effects in this study and possibly a larger dose or a longer duration of corticosteroid would have had an effect. Possibly, assessment of corticosteroid potency in suppressing established UV erythema rather than on the development of threshold erythema would have yielded different results.

CONCLUSION

The threshold UV erythema suppression model assessed in this study could not distinguish between oral prednisolone and placebo. This UV-erythema suppression test system is not promising as a model to test the anti-inflammatory potency of systemic steroids.

Morinda citrifolia Linn. (Rubiaceae) leaf extracts mitigate UVB-induced erythema

Morinda citrifolia Linn. (Rubiaceae) leaves have been used in tropical folk medicine to treat topical inflammation and burns. A carbomer gel base, containing the ethanol extract and juice pressed from the leaves, was evaluated for potential allergenic properties in a repeat-insult patch test in 49 volunteers. To investigate the topical photo-protective properties, the combined ethanol extract and leaf juice were evaluated in a UVB-induced erythema model in 25 volunteers. The crude ethanol extract of M. citrifolia leaves was also evaluated in vitro for potential anti-inflammatory activity in a histamine H-1 receptor antagonism assay. There was no evidence of allergenic potential in the repeat-insult patch test. When the combination of ethanol extract and leaf juice was applied, the UVB dose required to induce erythema was almost 3.5 times greater than with untreated skin (P < 0.001). In the histamine H-1 receptor-binding assay, the crude ethanol extract of M. citrifolia leaves inhibited receptor binding by 57%. These results suggest that M. citrifolia leaves are safe for topical use and may be useful in mitigating UVB-induced injury to the skin.

Inhibitory Effects of Mizolastine on Ultraviolet B–Induced Leukotriene B4 Production and 5-Lipoxygenase Expression in Normal Human Dermal Fibroblasts In Vitro

Ultraviolet B (UVB) irradiation exerts hazardous effects such as acute photodamage, skin cancer and photoaging. In this study we evaluated the protective effects of a nonsedative histamine H1-receptor antagonist, mizolastine, on UVB-exposed skin dermal fibroblasts. Therefore, primary human skin fibroblasts were incubated with mizolastine or dexamethasone after 100 mJ/cm(2) UVB irradiation. Leukotriene B4 (LTB4) in fibroblast supernatants was detected with enzyme immunoassays, expression of 5-lipoxygenase (5-LOX) messenger RNA (mRNA) in skin fibroblasts was examined by reverse transcriptase-polymerase chain reaction and expression of 5-LOX protein was measured by immune blotting and immunofluorescent staining with rabbit anti-human 5-LOX antibody. It was found that 0.01 mM mizolastine inhibited UVB-induced LTB4 production from skin fibroblasts at 12, 24 and 36 h. Meanwhile, mizolastine down-regulated 5-LOX mRNA expression and inhibited 5-LOX translocation from nucleus to cytoplasm in fibroblasts. On the basis of these findings, we propose that mizolastine might play a protective role in the pathogenesis of UV radiation-induced acute photodamage of the skin.

Adalimumab, a fully human anti-TNF-alpha monoclonal antibody, treatment does not influence experimental UV response in the skin of rheumatoid arthritis patients

TNF-alpha is known to play an important role in UV-induced immunomodulation and photodamage. It plays a role in UVB-mediated induction of apoptosis and is a strong inducer of the c-Jun N-terminal kinase (JNK) pathway, which eventually leads to the loss of dermal collagen and elastin content. Recently chimeric anti-TNF-alpha has been introduced as a therapy for rheumatoid arthritis. The aim of the present study was to investigate the effect of anti-TNF-alpha treatment on UV-induced DNA damage, apoptosis, and induction of matrix metallo proteinases. Twelve patients with rheumatoid arthritis were included and irradiated with 2 MED broadband UVB before and after administration of 0.5 mg/kg anti-TNF-alpha monoclonal antibody. Twenty-four hours after irradiation biopsies were taken. Frozen and paraffin sections were stained for p53, c-Jun, phosphorylated c-Jun, sunburn cells and MMP-1. No significant changes were observed in the expression of p53 and sunburn cells and MMP-1 content after treatment with anti-TNF-alpha, whereas a slight but significant decrease in c-Jun and phosphorylated c-Jun expression was noted (P = 0.0250 and P = 0.0431, respectively). Our results showed no influence of anti-TNF-alpha on UV response at therapeutic doses in patients with rheumatoid arthritis.