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Biomedical subjects

K Kragballe

Publications and source records attributed to K Kragballe.

At least 145 records · Page 8Linked to original sources
PubMed1987

Formation of epidermal cell thymocyte-activating factor (ETAF) from cultured human keratinocytes from normal and uninvolved psoriatic skin.

Cultures of keratinocytes from uninvolved psoriatic skin have been shown to exhibit increased DNA synthesis. Since epidermal cell-derived thymocyte-activating factor (ETAF) can stimulate the proliferation of human keratinocytes in vitro, we have compared the formation of ETAF in cultured keratinocytes from normal and uninvolved psoriatic skin. Trypsinized epidermal cells were plated at nonconfluent concentrations in dishes coated with a collagen type I gel. Normal keratinocyte cultures spontaneously released ETAF into the supernatant from day 1, reaching a maximum level (mean 124 +/- 4 units/micrograms DNA) on day 7, just before the cultures became completely confluent (days 9-12). The ETAF release then gradually decreased until a plateau (mean 16 +/- 7 units/micrograms DNA) was reached on day 18. In normal keratinocyte cultures the incorporation of [3H]thymidine into DNA changed in parallel with the ETAF release. Psoriatic keratinocytes had normal rates of ETAF release and of DNA synthesis until the time of culture confluency. However, when complete confluency was obtained, psoriatic keratinocytes continued to synthesize DNA at high levels (increased by 146% on day 15) while their ETAF release declined. Analysis of intracellular ETAF showed a significant correlation with the extracellular ETAF in cultures from both normal (r = 0.77, n = 10, p less than 0.02) and uninvolved psoriatic skin (r = 0.76, n = 12, p less than 0.01). These results indicate a relation between ETAF formation and DNA synthesis of normal keratinocyte cultures. However, factors other than ETAF appear to be responsible for the elevated DNA synthesis of confluent keratinocyte cultures from uninvolved psoriatic skin.

Adult↗
PubMed1987

Inhibition by leukotriene B5 of leukotriene B4-induced activation of human keratinocytes and neutrophils.

Leukotriene B5 (LTB5) that is generated enzymatically from eicosapentaenoic acid (EPA), was compared with arachidonic acid-derived LTB4 for its DNA synthetic effect on cultured human epidermal keratinocytes and for its chemokinetic effect on human blood neutrophils. Leukotriene B5 was much less potent than LTB4 in stimulating DNA synthesis and in inducing chemokinesis. Furthermore, the maximum response to LTB5 was only a mean of 38% that of LTB4 for mitogenesis and 70% that of LTB4 for chemokinesis. At an optimally active concentration of LTB4 (10(-10) M) the addition of LTB5 suppressed the enhancement by LTB4 of DNA synthesis in keratinocytes by a mean of 21%, 33%, and 54%, respectively, at 10(-9) M, 10(-8) M, and 10(-7) M LTB5. Leukotriene B5 inhibited to a lesser extent the maximum neutrophil chemokinetic response elicited by 10(-10) M LTB4 with mean inhibition of 10%, 20%, and 18%, respectively, by 10(-9) M, 10(-8) M, 10(-7) M LTB5; LTB5 was without effects on N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-elicited neutrophil chemokinesis and on thrombin-stimulated keratinocyte DNA synthesis. The dietary introduction of n-3 fatty acids, such as EPA, may reduce the epidermopoiesis and neutrophil migration evoked by LTB4 through decreases in generation of LTB4 and the capacity of LTB5 to inhibit the effects of LTB4.

Chemotaxis, Leukocyte↗
PubMed1987

Methotrexate inhibits the human C5a-induced skin response in patients with psoriasis.

In this study we examined the effects of intradermal injections of human complement split product C5a in 10 patients with psoriasis in long-term treatment with methotrexate (MTX). The C5a was injected at the end of the weekly MTX cycle just before the intake of the first MTX dose and 3 h after the second of the 3 doses. The C5a-induced skin response was evaluated by measuring the diameter of the wheal and the area of the flare and by erythema index (EI), which was determined objectively by reflectance spectrophotometry. In all patients the skin response was significantly depressed when C5a was injected after MTX intake. The decrease of wheal, flare, and EI averaged 61.6%, 71.1%, and 57.5%, respectively, when all parameters were obtained at maximal skin response. The in vitro chemotaxis of peripheral blood neutrophils and monocytes from the patients toward C5a was markedly inhibited after intake of MTX (p less than 0.01). The skin biopsies obtained after C5a injection before intake of MTX revealed a perivascular inflammatory infiltrate and considerable dermal edema. After MTX intake the number of infiltrating leukocytes and the degree of dermal edema was markedly reduced. This study indicates that MTX is a potent inhibitor of C5a-induced skin inflammation, and that this inhibition may be caused by a direct effect on circulating neutrophils and monocytes. The results obtained in this work support the idea that anti-inflammatory effects of MTX may be partially responsible for its antipsoriatic effect.

Adolescent↗
PubMed1987

Single dose pharmacokinetics of etretin and etretinate in psoriatic patients.

Etretin, an aromatic retinoic acid derivative, has recently been introduced as a possible substitute for etretinate in the treatment of severe psoriasis and other dyskeratoses. A total of nine patients with psoriasis of either sex in the age range 23-76 years was investigated after single dose oral drug administration, six were given 40 mg of etretin and three 40 mg of etretinate. A newly developed reversed-phase HPLC method was applied for simultaneous determination of etretin and etretinate in plasma. In patients receiving etretinate, the lag-time i.e. the time elapsing until appearance of first-order drug absorption was 1.24 +/- 0.27 for the parent drug and 0.69 hrs +/- 0.16 (mean value +/- S.D.) for its metabolite, etretin. Absorption half-times were 0.86 +/- 0.04 and 0.55 hrs +/- 0.09, respectively. The patients receiving etretin showed a lag-time of 0.42 hrs +/- 0.23 and an absorption half-time of 0.33 hrs +/- 0.28. This suggests that a fraction of etretinate is rapidly hydrolysed to etretin during the absorption process. The mean half-times of the distributory phases of disposition for etretinate and etretin were about 1 and 1.3 hrs and the apparent terminal half-lives were 6.57 +/- 2.09 and 5.52 hrs +/- 1.76, respectively. Assuming 40% systemic availability for both drugs the mean apparent volumes of distributions were calculated to be 1.50 +/- 0.46 and 1.31 l X kg-1 +/- 0.53 and mean plasma clearances were 177.8 +/- 105.8 and 175.9 ml X kg-1 X hr-1 +/- 81.4 for etretinate and etretin, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acitretin↗
PubMed1986

Arachidonic acid metabolites in cutaneous carcinomas. Evidence suggesting that elevated levels of prostaglandins in basal cell carcinomas are associated with an aggressive growth pattern.

There is evidence suggesting a role of eicosanoids in the growth of certain tumors. In this study, tissue samples were collected from basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin. Both BCCs and SCCs contained more prostaglandin E2 and F2 alpha (PGE2 and PGF2 alpha) than normal epidermis. In vitro incubation of tumor samples with arachidonic acid also resulted in PGE2 and PGF2 alpha formation. Basal cell carcinomas exhibiting a histologically aggressive growth pattern contained higher levels of prostaglandins than those with a nonaggressive growth pattern, both in vivo and after in vitro incubation. Lipoxygenase products (12- and 15-hydroxyeicosatetraenoic acid) were present in smaller amounts than cyclo-oxygenase products (PGE2 and PGF2 alpha) in vivo. Compared with normal epidermis, SCCs and, particularly, BCCs produced smaller amounts of 12-hydroxyeicosatetraenoic acid during in vitro incubation with arachidonic acid. The levels of lipoxygenase products were not related to the tumor growth pattern. These results indicate that excessive prostaglandin levels in BCCs may be associated with an aggressive growth pattern.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Chemotactic lipoxygenase products in sera from patients with psoriasis.

Sera obtained from 12 patients with moderate to severe psoriasis were investigated for the presence of arachidonate lipoxygenase metabolites using reverse-phase high-performance liquid chromatography after extraction on silicic acid columns. Peaks which co-chromatographed with standards of synthetic leukotriene B4 (LTB4) were collected, and the material was tested for chemotactic activity. In the sera of 5 of the patients, chemotactic activity was demonstrable in these 'LTB4' peaks. Although minor peaks co-chromatographing with LTB4 were found in control sera, none of them contained chemotactic material. Isolated monocytes from the psoriasis patients showed enhanced chemotactic activity as compared to monocytes obtained from healthy controls. The results of our study support the view that abnormal 5-lipoxygenase activity is present in psoriasis. Further investigation is required to determine whether LTB4 is released from circulatory leukocytes or the skin.

Adult↗
PubMed1986

Increased aggregation and arachidonic acid transformation by psoriatic platelets: evidence that platelet-derived 12-hydroxy-eicosatetraenoic acid increases keratinocyte DNA synthesis in vitro.

Certain arachidonic metabolites may play a pathogenic role in psoriasis. Platelets are rich sources of 12-hydroxy-eicosatetraenoic acid (12-HETE) and thromboxane A2, mediators of skin inflammation and platelet aggregation, respectively. We have studied untreated psoriatic patients without a history of diabetes mellitus and smoking. In psoriatics, platelet aggregation elicited by thrombin, ADP, and ristocetin was significantly enhanced as compared with healthy adult volunteers. Enhancement of platelet aggregation was detected in patients with both minimal and widespread disease. The formation of 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), a cyclooxygenase product, and 12-HETE, a 12-lipoxygenase product, was increased in psoriatics with widespread disease but not in those with minimal disease. Formation of 12-HETE was stimulated to a higher degree (125%) than HHT (98%) in psoriasis (P less than 0.05). Addition of platelet-derived 12-HETE to cultured human epidermal keratinocytes resulted in a stimulation of the DNA synthesis (68% at 10(-7) M). These data suggest that platelet activation occurs in psoriasis, and that release of inflammatory and mitogenic compounds by activated platelets may play a role in the pathophysiology of psoriasis. Whether enhanced platelet aggregation in psoriasis is associated with occlusive vascular disease needs further investigation.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Dermis-derived 15-hydroxy-eicosatetraenoic acid inhibits epidermal 12-lipoxygenase activity.

The purpose of the present study was to analyze the metabolism of arachidonic acid (AA) in normal human dermis. After incubating homogenized dermis with exogenous AA, the extracted lipids were isolated by reversed-phase high-performance liquid chromatography. Each chromatographic peak was characterized by its UV absorption spectrum and identified by its coelution with the appropriate authentic standard and by radioimmunoassay of its eluate fraction. Identified compounds were quantitated by integrated optical density. Homogenized human dermis transformed AA into both cyclooxygenase and lipoxygenase products, but predominantly 15-hydroxy-eicosatetraenoic acid (15-HETE). Cultured fibroblasts from normal human dermis also mainly metabolized AA into 15-HETE. To determine whether dermis-derived 15-HETE might modify the AA metabolism of epidermis, normal human epidermis was incubated with dermis. Increasing amounts of dermis resulted in an increasing inhibition of epidermal 12-HETE formation. Similarly, 15-HETE alone induced a dose-dependent decrease of epidermal 12-HETE formation, while the formation of prostaglandin E2 was unchanged. Since 12-HETE possess the ability to elicit skin inflammation and to stimulate epidermal DNA synthesis, 15-HETE formation may be a way whereby dermis regulates important epidermal activities.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

In vitro synthesis of 12-hydroxy-eicosatetraenoic acid is increased in uninvolved psoriatic epidermis.

Certain arachidonic acid (AA) metabolites have been detected in psoriatic skin lesions. In this study the capacity of normal epidermis and clinically uninvolved psoriatic epidermis to transform AA into lipoxygenase products was determined in vitro. After incubating homogenized epidermis with exogenous AA, the extracted lipids were isolated by reverse-phase high-performance liquid chromatography. Each chromatographic peak was characterized by its UV absorption spectrum and identified by its coelution with the appropriate authentic standard and by radioimmunoassay of its eluate fraction. Identified compounds were quantitated by integrated UV absorbance. Leukotriene B4 (LTB4) was also identified by neutrophil chemokinesis. Normal epidermis generated 15-hydroxy-eicosatetraenoic acid (15-HETE) and 12-HETE, the latter being more abundant. 5-Lipoxygenase products (LTB4, LTC4, and 5-HETE) were not detected. However, an unknown compound exhibiting a triplet UV absorbtion spectrum with maximum at 274 mm was formed. Its formation was inhibited by 5,8,11,14-eicosatetraynoic acid, but not by indomethacin or a specific 5-lipoxygenase inhibitor (REV 5901). These data suggest that a di-HETE with a triene structure is one possible candidate for the unknown compound. Compared with normal epidermis, the formation of 12-HETE and the unknown di-HETE by uninvolved psoriatic epidermis was increased by 54% and 63%, respectively. The formation of 12-HETE and the unknown di-HETE in uninvolved psoriatic epidermis was stimulated to the same degree in the presence of the phospholipase inhibitor quinacrine. These results indicate that uninvolved psoriatic epidermis has an increased capacity to metabolize free AA into 12-lipoxygenase products.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Effects of dietary supplementation of fish oil on neutrophil and epidermal fatty acids. Modulation of clinical course of psoriatic subjects.

Findings from an eight-week fish oil-supplemented diet given to 13 psoriatic patients demonstrated that eicosapentaenoic acid (20:5,n3 [EPA]) and docosahexaenoic acid (22:6,n3 [DCHA]) are rapidly incorporated into the sera, neutrophils, and epidermis of participating patients, and that the incorporation of EPA and DCHA into epidermal lipids increased with weeks of supplementation with minimal alteration of arachidonic acid (AA) in the epidermal lipids. Global clinical evaluation showed that eight patients demonstrated mild to moderate improvement in their psoriatic lesions. Improved clinical response correlated with high EPA/DCHA ratios attained in epidermal tissue specimens. These findings underscore the need for further investigations into the role of dietary n3 fatty acids, particularly the possibility of pentaenoic acid as a potential protective agent and/or therapeutic adjunct for the clinical management of psoriasis.

Adult↗
PubMed1986

Selective decrease of 15-hydroxyeicosatetraenoic acid (15-HETE) formation in uninvolved psoriatic dermis.

Epidermis of psoriatic skin lesions is characterized by elevated 5-lipoxygenase and 12-lipoxygenase products. 15-hydroxyeicosatetraenoic acid (15-HETE), the predominant lipoxygenase product in normal dermis, has the potential to inhibit 5-lipoxygenase and 12-lipoxygenase. The purpose of the present study was to determine the capacity of homogenized dermis from uninvolved psoriatic skin to form 15-HETE in vitro. Extracted lipids were separated by reversed-phase high-performance liquid chromatography. Each chromatographic peak was identified by its coelution with authentic standards, by ultraviolet spectrometry, and by radioimmunoassay. Dermis from uninvolved psoriatic skin generated on average 48% less 15-HETE than normal dermis (P less than .01). In contrast, the formation of 12-hydroxyeicosatetraenoic acid was increased by 56% in psoriatic dermis (P less than .01). Prostaglandin E2 formation was similar in normal and psoriatic dermis. Since 15-HETE can inhibit the synthesis of 5-lipoxygenase and 12-lipoxygenase products that possess inflammatory and proliferative capacities, a defective 15-HETE generation in dermis may be of importance for the development of psoriasis.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1985

Leukotrienes B4, C4 and D4 stimulate DNA synthesis in cultured human epidermal keratinocytes.

Leukotrienes in psoriatic skin lesions are potent mediators of inflammation. We have studied the capacity of leukotrienes to stimulate the DNA synthesis of cultured human epidermal keratinocytes. At concentrations ranging from 10(-12) to 10(-8) M, LTB4 produced a 100% increase of DNA synthesis determined both as the incorporation of [3H] thymidine and as the labelling index. In comparison, LTB4 had no effect on the DNA synthesis of dermal fibroblast cultures. 5S,12S-LTB4 and 5S,12S-all-trans-LTB4 did not change the DNA synthesis of keratinocytes, but the effect of LTB4 was abolished in the presence of 5S,12S-all-trans HLTB4. Being less potent than LTB4 the peptidoleukotrienes (LTC4, LTD4) also stimulated keratinocyte DNA synthesis. The effect of the peptidoleukotrienes, but not of LTB4, was antagonized by FPL 55712. These results show that leukotrienes B4, C4 and D4 exert potent and stereospecific mitogenic effects on cultured human keratinocytes. The presence of these arachidonic acid metabolites in psoriatic skin lesions may be pertinent to both inflammation and aberrant epidermal growth in psoriasis.

Adult↗
PubMed1985

Increased DNA synthesis of uninvolved psoriatic epidermis is maintained in vitro.

Clinically uninvolved psoriatic epidermis shows increased DNA synthesis in vivo. We have studied the DNA synthesis of cultured keratinocytes from uninvolved psoriatic skin. Trypsinized epidermal cells were plated on plastic dishes pre-coated with bovine collagen type I. In initial studies, normal human serum was found to be superior to fetal bovine in supporting the growth of human epidermal keratinocytes. Furthermore, keratinocyte cultures established in the presence of normal human serum produced large keratin proteins (68,000 daltons) indicating that the terminal steps in cell differentiation can occur in vitro. In subsequent experiments keratinocyte cultures were grown in medium supplemented with 10% normal human serum. Confluent cultures of keratinocytes from uninvolved psoriatic epidermis had an increased DNA synthesis determined both as the incorporation of [3H]thymidine and as the autoradiographic labelling index. The DNA synthesis of both normal and psoriatic keratinocyte cultures increased in response to incubation in medium with 10% psoriatic serum. The ability of keratinocytes from uninvolved psoriatic epidermis to maintain an increased DNA synthesis suggests the presence of an inherent defect within the population of epidermal keratinocytes in psoriasis. Such a culture system can be used as an in vitro model for the study of psoriasis.

Adult↗