Vascular endothelial growth factor causally contributes to the angiogenic response upon ultraviolet B irradiation in vivo

BACKGROUND

Ultraviolet (UV)-B irradiation has been shown to be an inducer of vascular endothelial growth factor (VEGF) in primary keratinocytes and epidermal cell lines in vitro.

OBJECTIVES

To determine the expression pattern and the causal role of VEGF in the UVB-mediated angiogenic response in vivo in human skin and in a mouse model.

METHODS

Skin biopsies or epidermal lysates thereof were studied for VEGF expression following UVB irradiation at a dose of 50 or 60 mJ cm-2, respectively, using immunostaining and a VEGF-specific highly sensitive sandwich enzyme-linked immunosorbent assay. The VEGF-dependent increase in vessels upon repetitive UVB irradiation was studied in skh-1 hairless mice using immunostaining for factor VIII-related antigen (FVIII RAG) in the presence and absence of intraperitoneally injected neutralizing VEGF antibodies.

RESULTS

VEGF was found to be induced in the epidermis following UVB irradiation of human and mouse skin. Repetitive UVB irradiation of skh-1 hairless mice resulted in an increase in FVIII RAG positive vessels in the skin. UVB-induced angiogenic response could be partly abrogated by neutralizing antibodies against VEGF, while isotype-matched IgG control antibodies did not reveal any suppressive effect.

CONCLUSIONS

Our results support previous in vitro data and show the in vivo relevance of VEGF as a paracrine inducer of cutaneous vessels after UVB irradiation.

Anaphylactoid reactions after cisatracurium administration in six patients

IMPLICATIONS

We report six cases of anaphylactoid reaction after the administration of the muscle relaxant cisatracurium. They include two first-time documented anaphylactoid reactions after a precurarising dose. These incidents challenge existing views of a substantially reduced anaphylactoid potential of cisatracurium relative to other muscle relaxants.

Different pattern of collagen cross-links in two sclerotic skin diseases: lipodermatosclerosis and circumscribed scleroderma

Changes in the process of cross-linking of collagen molecules are associated with defects in the biomechanical stability of the extracellular matrix. Fibrosis of skin is characterized by an increase in pyridinolines, which are hydroxylysine aldehyde derived cross-links usually absent in healthy skin. In this study, we analyzed cross-links in lipodermatosclerosis and localized scleroderma to address the question whether all the mature cross-links currently characterized are increased in fibrosis in addition to the increase in pyridinolines. As psoralen plus ultraviolet A treatment leads to clinical improvement of fibrotic plaques in localized scleroderma we analyzed the cross-link content in lesional skin after bath psoralen plus ultraviolet A therapy. In skin from patients with localized scleroderma an increase in the total number of mature cross-links was found to be due to an increase in both pyridinolines and dehydro-histidinohydroxymerodesmosine. The concentration of histidinohydroxylysinonorleucine was unchanged. By contrast, the total number of mature cross-links was decreased in lipodermatosclerosis. This decrease was caused by a decrease of lysine aldehyde derived cross-links (dehydro-histidinohydroxymerodesmosine and histidinohydroxylysinonorleucine), whereas the concentration of pyridinolines increased. A decrease in the content of pyridinolines after bath psoralen plus ultraviolet A treatment was found in six out of nine patients with localized scleroderma, which might reflect a remodeling of the extracellular matrix. Our data provide evidence that sclerosis of skin is associated with either an increase in the number of cross-links per molecule of collagen or a change in the molecular nature of the cross-links formed.

Increased deposition of fibulin-2 in solar elastosis and its colocalization with elastic fibres

BACKGROUND

Fibulin-2 is a 195-kDa protein belonging to a novel family of extracellular matrix proteins that might be involved in microfibril and elastic fibre organization.

OBJECTIVES

To determine the localization of fibulin-2 in relation to elastic fibres in normal skin and in solar elastosis characterized by increased elastotic material in the papillary dermis.

METHODS

The expression and synthesis of fibulin-2 was investigated by means of in situ hybridization, immunohistochemistry and Western blot analysis in normal and photoaged skin.

RESULTS

Immunohistochemistry and elastic tissue staining revealed that fibulin-2 deposition mainly colocalized with microfibrils and elastin fibres, with a marked staining of elastotic material in solar elastosis. Western blot analysis demonstrated that in photoaged skin fibulin-2 showed the same electrophoretic mobility as in sun-protected skin. However, in actinic elastosis the amount of fibulin-2 was significantly higher. In addition, smaller degradation products were detectable, presumably reflecting increased proteinase activity in photodamaged skin.

CONCLUSIONS

This study shows that deposition of fibulin-2 and elastin is highly co-ordinated, indicating that this protein plays an important role in elastic fibre and microfibril formation in normal and actinically damaged skin.

Linear IgA bullous dermatosis induced by atorvastatin

Linear IgA bullous dermatosis (LABD) is an autoimmune blistering skin disease characterized by circulating IgA antibodies binding the basement membrane zone. In most cases the origin is not clear, but in a minority of cases LABD is drug induced. We describe a patient in whom linear IgA disease developed shortly after beginning therapy with atorvastatin. In Western blotting analysis we detected IgA and IgG class antibodies targeting a 97-kd protein. To our knowledge this is the first reported case of atorvastatin-induced LABD.

Rapid enrichment and detection of melanoma cells from peripheral blood mononuclear cells by a new assay combining immunomagnetic cell sorting and immunocytochemical staining

Commonly used methods for detection of melanoma cells in blood, including RT-PCR and immunocytochemistry, display only a limited sensitivity and specificity. Reliable detection of less than one melanoma cell per ml of blood is hardly possible using these methods. To obtain greater sensitivity so that a single melanoma cell in up to 25 ml of blood can be detected (5 x 10(7) peripheral blood mononuclear cells, or PBMC), we developed a new assay for combined enrichment and immunocytochemical detection of disseminated melanoma cells from PBMC of patients with malignant melanomas. Melanoma cells are directly magnetically labeled using colloidal superparamagnetic microparticles approximately 60 nm in diameter conjugated to the anti-melanoma monoclonal antibody 9.2.27, with no reactivity to normal cells in blood. Magnetically labeled melanoma cells are enriched from PBMC by magnetic cell separation and detected by a new approach for immunocytochemical staining with monoclonal mouse anti-melanoma antibodies (anti-MelanA and HMB-45). The efficiency of this assay was demonstrated in a model system in which 5-500 tumor cells from the melanoma cell line SK-MEL-28 were seeded into PBMC samples from healthy donors containing 5 x 10(7) leukocytes. Mean recovery of the seeded tumor cells was 47.4 +/- 13.99% (n = 15). Applying the assay to 20-50 ml blood samples of patients with stage III-IV malignant melanomas, we were able to detect melanoma cells in two of eight patients (25%).

Bullous pemphigoid in a patient treated with UVA-1 phototherapy for disseminated morphea

Bullous pemphigoid is an autoimmune disease of the skin characterized by the production of antibodies directed at structures of the basement membrane zone (BMZ) leading to subepidermal blisters. Several causative triggers have been described in the literature, among them UV light. Here, we report on a 73-year-old Caucasian female with disseminated morphea who developed blisters on her extremities after receiving whole-body UVA-1 phototherapy. The initial differential diagnosis of a phototoxic versus photoallergic reaction was ruled out as the lesions continued to spread after discontinuation of phototherapy. Histological and direct immunofluorescence examination showing a subepidermal blister and linear IgG deposits along the BMZ along with detection of circulating anti-BMZ antibodies led to the diagnosis of bullous pemphigoid. Immunosuppressive therapy resulted in regression of all blisters. After ruling out other possible causes, such as neoplasias or drugs, we conclude that UVA-1 has to be regarded as the most likely trigger of the disease.

New insights into the pathomechanisms of contact dermatitis by the use of transgenic mouse models

Allergic contact dermatitis (ACD) is one of the most common skin diseases with a great socioeconomic impact. Although extensively studied, its pathophysiology and the interaction of different cells and factors which lead to sensitization and elicitation reaction are still not completely understood. The advent of transgenic mouse technology has considerably changed the study of ACD. This technology has been used extensively to investigate biomedically important issues in such diverse areas as mammalian development, neurophysiology and immunology. This new approach has already led to fascinating results which are confirmatory but also contradictory to previous thinking on the role of certain cytokines, adhesion and cell surface molecules in the complex pathophysiologic process of ACD. This review will describe how recent experiments employing mice carrying cytokine and accessory molecule transgenes change our current understanding of contact dermatitis which may lead to improved therapeutic strategies.

Immediate reaction to roxithromycin and prick test cross-sensitization to erythromycin and clarithromycin

Allergic reactions to macrolides appear to be very rare. Only a few cases of fixed drug eruption or urticaria due to the administration of erythromycin have been reported. Cross-reaction between the different macrolides have not yet been published. We report a case of a 31-year-old female patient who developed generalized urticaria and tachycardia shortly after administration of roxithromycin (Rulid). Immediate-type hypersensitivity was confirmed by positive prick test reactions to roxithromycin and the chemically closely related macrolides erythromycin and clarithromycin.

Stevens-Johnson syndrome-like exanthema secondary to methotrexate histologically simulating acute graft-versus-host disease

A 61 year old male patient suffering from psoriasis vulgaris developed a severe skin reaction with toxic myelosuppression three days after administration of 20 mg methotrexate (MTX) p.o. per week and concomitant 100 mg acetylic salicylic acid (ASA) per day. The skin lesions simulated Stevens-Johnson syndrome with ulcerations of the oral mucosa and erythema multiforme-like target lesions. The histology of the epidermis resembled an acute graft-versus-host reaction. The increased toxic effect of MTX on keratinocytes in our patient was most likely caused by a lowered plasma binding capacity and reduced renal excretion of MTX due to concomitant administration of ASA. Thus in the treatment of severe forms of psoriasis with MTX, the combined administration of drugs aggravating MTX toxicity, particularly of ASA, should be carefully considered, due to the increased toxicity and risk of severe skin reactions.

Discrete papular mucinosis-a rare subtype of lichen myxoedematosus

Lichen myxoedematosus is an uncommon and distinct disease entity characterized by cutaneous mucin deposition which, depending on the distribution and overall skin involvement, can be classified into several subtypes. We now describe the case of a discrete papular type of lichen myxoedematosus in a patient without any conspicious laboratory findings including normal thyroid function and the absence of any abnormal immunglobulins.

Treatment of pruritus by capsaicin in a patient with pityriasis rubra pilaris receiving RE-PUVA therapy

Pityriasis rubra pilaris (PRP) is characterized by redness of the skin, scaling and a variable degree of pruritus. We present a patient with extremely itchy PRP successfully treated with oral retinoids and photochemotherapy with 8-methoxypsoralene (RE-PUVA) and topical capsaicin. The PRP-related pruritus which clearly preceded photochemotherapy and for which no other cause was apparent was relieved with capsaicin. This single case report provides evidence that topical capsaicin may be a useful therapeutic option in treating PRP-associated pruritus where antihistamines have been unsuccessful.