Biomedical subjects

J B Nissen

Publications and source records attributed to J B Nissen.

7 recordsLinked to original sources

PubMed1999

Effect of intradermal injection of methionine-enkephalin on human skin.

Methionine-enkephalin (met-enk) detected in monocytes in psoriatic skin can modulate inflammatory processes and keratinocyte differentiation/proliferation in vitro. The purpose of the present study was to determine the effect of intradermal injection of met-enk on normal human skin and on the development of a delayed type skin hypersensitivity reaction. In 6 healthy volunteers, 50 microl of met-enk (16, 30, and 45 nmol) was injected once in the forearm and the reaction was evaluated clinically and by video-optical recording for 120 min. Compared to vehicle (0.9% saline), met-enk induced a time- and dose-dependent flare reaction, but no significant stimulation of a weal reaction. The flare reaction was maximal after 1 min and disappeared within 45 min. Pre-treatment with the antihistamine cetirizine reduced the flare reaction. Furthermore, the effect of met-enk on lymphocyte/monocyte infiltration and epidermal proliferation in normal skin and on a delayed type skin hypersensitivity reaction was assessed. Met-enk (45 nmol/ 50 microl) was injected at 0, 24 and 48 h. In normal skin, met-enk increased the number of dermal lymphocytes/monocytes (CD3/CD68 positive cells) and the degree of epidermal proliferation (MIBI-Ki67). In a delayed type hypersensitivity reaction induced by tuberculin (PPD), the degree of epidermal proliferation and the number of infiltrating lymphocytes/monocytes were reduced compared to PPD alone. Our study suggests that intradermal injection of met-enk in normal human skin induces an inflammatory reaction that may involve the release of histamine. In contrast, met-enk seems to down-regulate the development of a delayed type skin hypersensitivity reaction. These results may indicate that the direction of the effect of the opioid peptide met-enk on human skin depends on the rate of epidermal proliferation and the activity of immunocompetent cells.

Adult↗

PubMed1999

Decrease in enkephalin levels in psoriatic lesions after calcipotriol and mometasone furoate treatment.

BACKGROUND: Enkephalins are opioid peptides that can modulate immune responses and inflammatory processes. Furthermore, they inhibit keratinocyte proliferation/differentiation in vitro. Previously, we have shown that enkephalins are present in increased amounts in lesional psoriasis. OBJECTIVE: To determine the effect of topical treatment with the vitamin D analogue calcipotriol and the corticosteroid mometasone furoate on the level of methionine-enkephalin (enk) in psoriatic lesions. METHODS: Twelve psoriatic patients were treated with calcipotriol and mometasone furoate for 14 days without or with hydrocolloid occlusion. Keratome biopsies were obtained from treated and untreated skin, and the extracted enk was quantified by radioimmunoassay. Furthermore, punch biopsies were obtained for immunohistochemical analysis. RESULTS: Clinically, both calcipotriol and mometasone furoate improved psoriasis to the same degree, the effects being more pronounced after occlusion. Histologically, treatment with mometasone furoate without occlusion decreased both the epidermal thickness/parakeratosis and the number of dermal immunocompetent cells (CD3- and CD68-positive cells). In contrast, treatment with calcipotriol without occlusion reduced the epidermal thickness and the degree of parakeratosis but decreased the number of CD3- and CD68-positive cells only slightly. The mean enk level was decreased by 26 and 86% by calcipotriol without and with occlusion and by 16 and 63% by mometasone furoate without and with occlusion, respectively. The decreases in the enk levels corresponded to the degree of clinical improvement but not to the histological changes. CONCLUSION: The increased levels of enk in psoriatic lesions are reduced in parallel with the clinical improvement induced by a topical vitamin D analogue and a corticosteroid. Because enkephalins can modulate epidermal differentiation and inflammatory processes, the findings indicate that enkephalins may play a role in the pathogenesis of psoriasis.

Administration, Topical↗

PubMed1998

Increased levels of enkephalin following natural sunlight (combined with salt water bathing at the Dead Sea) and ultraviolet A irradiation.

The opioid peptides enkephalins have been shown to modulate inflammatory responses and keratinocyte proliferation and differentiation. Furthermore, increased levels of enkephalin are present in psoriatic lesions. The purpose of the present study was to determine the effect of natural sunlight combined with salt water bathing in the Dead Sea on the methionine-enkephalin (e.n.k.) level in psoriatic skin. Ten patients were treated at the Dead Sea for 4 weeks, and keratotome biopsies were obtained before and after treatment. The amount of enkephalin extracted from the biopsies was measured by radioimmunoassay. Treatment at the Dead Sea resulted in a complete clinical clearance of psoriasis, and immunohistochemical stainings of lesional skin showed that the treatment decreased both epidermal thickness/parakeratosis and the dermal infiltration of CD3- and CD68-positive cells, although the number of CD3- and CD68-positive cells became normal in only two of the 10 cases. However, there was only a slight decrease in the mean enk levels (21%). Furthermore, the level of enk was high in non-lesional psoriatic skin after treatment at the Dead Sea, and immunostaining showed that, in some patients, the treatment induced a mild epidermal hyperplasia and a dermal infiltration of CD3- and CD68-positive cells. Enkephalin-like immunoreactivity was detected in the cytoplasm of both epidermal keratinocytes and dermal infiltrating cells. To determine whether the relatively high skin enk levels after treatment at the Dead Sea was caused by ultraviolet (UV) radiation, normal volunteers were exposed to a single dose of UVA and UVB (2 minimal erythema doses). UVA, but not UVB, irradiation stimulated the mean enk level in the irradiated skin by about sixfold. Furthermore, multiple whole-body UVA irradiations not only resulted in increased skin levels of enk, but also in increased plasma levels. In conclusion, natural sunlight combined with salt water bathing cleared psoriasis without causing a significant decrease in lesional enk levels. Furthermore, non-lesional enk levels were increased. These findings may be the result of a direct stimulatory effect of UVA irradiation on enk formation in the skin. It is possible that the increased circulating levels of enk after UV exposure may contribute to the beneficial effects of UVA irradiation.

Adult↗

PubMed1997

Enkephalin-like immunoreactivity in human skin is found selectively in a fraction of CD68-positive dermal cells: increase in enkephalin-positive cells in lesional psoriasis.

Opioid peptides are synthesized in neurons, endocrine cells, monocytes/macrophages and B and T lymphocytes. They interact with opioid receptors located on immune cells and nociceptive nerve terminals. Because opioid peptides might be of importance in inflammatory skin diseases, for example psoriasis, sections of skin from psoriatic patients were immunohistochemically stained with antisera against methionine and leucine enkephalin, CD68 (KP1, PG-M1), calprotectin (M747), M130 (Ber-MAC3), CD1a and CD3. Enkephalin-like activity was detected selectively in dermal CD68-positive macrophages/monocytes. The activity showed no association with the activation markers M747 and Ber-MAC3. There was a statistically significant increase in enkephalin-positive cells in involved psoriatic skin compared with uninvolved and normal skin. These results were confirmed by radioimmunoassay which showed elevated levels in extracts from involved psoriatic skin compared with uninvolved skin (81%) and normal skin (204%). Furthermore, preproenkephalin mRNA of an expected size was detected in involved psoriatic skin. If the increased levels of enkephalins present in monocytes/macrophages in psoriatic skin lesions reach the threshold for biological activity, they may play a role in the regulation of the inflammatory processes seen in this skin disease.

Adult↗

PubMed1997

Enkephalins modulate differentiation of normal human keratinocytes in vitro.

Opioid peptides are a group of neuropeptides which include enkephalins, endorphins and dynorphins. In addition to their central and peripheral antinociceptive function, opioids can modulate immune activity and cell proliferation. Previously, we have shown that enkephalins are present in macrophages infiltrating the dermal papillae in involved psoriatic skin and that the amount of enkephalin is significantly increased in involved psoriatic skin. Because enkephalins were detected close to the epidermis, we examined the effects of opioid peptides on the differentiation (transglutaminase type 1 activity and cytokeratin 10 expression) and proliferation (MTT assay) of cultured human keratinocytes. Enkephalins (methionine-enkephalin, leucine-enkephalin and the synthetic DADL) inhibited cell differentiation dose-dependently, while beta-endorphin had no effect. The opioid receptor antagonist naltrexone completely antagonized the inhibitory effect of methionine-enkephalin and leucine-enkephalin, but not that of DADL. Furthermore, methionine-enkephalin had a slight inhibitory effect on the proliferation of keratinocytes. Enkephalin was detected in unstimulated keratinocyte cultures, and naltrexone alone stimulated keratinocyte differentiation. These results indicate that enkephalins may play a role in the differentiation of epidermal keratinocytes. It remains to be determined whether the enkephalin detected in psoriatic skin are sufficient to affect epidermal differentiation in vivo.

Cell Differentiation↗

PubMed1995

Purification and characterization of leukotriene A4 hydrolase from human epidermis.

The leukotriene A4 hydrolase is a central enzyme in leukotriene B4 formation. Unlike 5-lipoxygenase, leukotriene A4 hydrolase activity is present in normal human epidermis, where it is likely to be involved in transcellular leukotriene formation. In this study the leukotriene A4 hydrolase was purified from human epidermis and human cultured keratinocytes and compared with leukotriene A4 hydrolase from human neutrophils. To purify leukotriene A4 hydrolase from human epidermis a new non-specific affinity chromatography column, with the leukotriene A4 hydrolase inhibitor bestatin coupled to AH-Sepharose, was introduced. The epidermal leukotriene A4 hydrolase was purified to apparent homogeneity and the molecular weight was determined to be approximately 70,000 Da by SDS-PAGE. The pI was 5.1-5.4 for the epidermal as well as the keratinocyte and neutrophil leukotriene A4 hydrolase, as determined by chromatofocusing. Only minor differences in the amino acid composition were seen between the three enzyme sources. The optimal pH for the hydrolase activity was 7.5-8.5 for the epidermal and neutrophil leukotriene A4 hydrolases. Finally, it was also shown that the epidermal leukotriene A4 hydrolase undergoes suicide inactivation when transforming leukotriene A4 into leukotriene B4. It was concluded that there is a close resemblance between the epidermal leukotriene A4 hydrolase and the hydrolase found in other cell types. Therefore, the human epidermis may be a good model for the in vivo study of transcellular leukotriene formation.

Cells, Cultured↗

PubMed1995

Characterization of the aminopeptidase activity of epidermal leukotriene A4 hydrolase against the opioid dynorphin fragment 1-7.

Leukotriene A4 hydrolase is a bifunctional cytosolic enzyme, which both hydrolyses leukotriene A4 (LTA4) into leukotriene B4 (LTB4) and exerts aminopeptidase activity against opioid peptides. In the present study we have investigated whether the peptides angiotensin I and II, bradykinin, kallidine, histamine, dynorphin fragment 1-7 and substance P can act as substrates for epidermal and neutrophil LTA4 hydrolase. Among the tested substrates, dynorphin fragment 1-7 was found to be the best substrate for the enzyme. The aminopeptidase activity of epidermal and neutrophil LTA4 hydrolase against dynorphin fragment 1-7 was further characterized. The enzyme was purified from human epidermis and human neutrophils by anion exchange chromatography (Q-Sepharose) and affinity chromatography on a column with the LTA4 hydrolase inhibitor bestatin coupled to AH-Sepharose. The incubation of the dynorphin fragment 1-7 with LTA4 hydrolase resulted in the formation of tyrosine. The presence of the N-terminal amino acid tyrosine is essential for the interaction of opioids with their receptors, and this finding indicates that the LTA4 hydrolase can inactivate dynorphin fragment 1-7. After the two purification steps no other aminopeptidases acting at the N-terminal tyrosine of dynorphin fragment 1-7 was present in the preparation. This was demonstrated by the abolishment of the degradation at the N-terminal end of dynorphin fragment 1-7 when preincubating the enzyme preparation with LTA4 before the incubation with the dynorphin fragment 1-7. The abolishment of the aminopeptidase activity shows that activation of the hydrolase part of the enzyme, with conversion of LTA4 into the potent proinflammatory compound LTB4, results in an inhibition of the aminopeptidase activity of the enzyme. As a result, the catabolism of dynorphin fragment 1-7 and probably of other opioid peptides is inhibited, resulting in sustained biological effects of these opioids. This phenomenon may be important for the maintenance of inflammation in skin conditions, such as psoriasis and atopic dermatitis, in which LTB4 is formed.

Amino Acid Sequence↗