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.     

Breast-cancer-associated stromelysin-3 gene is expressed in basal cell carcinoma and during cutaneous wound healing.

Ten cases of basal cell carcinoma (BCC), including nine of the nodulo-ulcerative type and one of the morphea-form type, were investigated for stromelysin-3 (ST3) gene expression by in situ hybridization. The ST3 gene, which codes for a putative matrix metalloproteinase expressed in stromal cells of invasive breast carcinomas, was also expressed in stromal cells of BCCs when they displayed active local invasiveness. ST3 RNA was specifically detected in fibroblastic cells of tumor areas exhibiting loss of peripheral palisading in cancer cell islands. This pattern of expression was characteristic of the ST3 gene and was not observed with any of the other matrix metalloproteinase genes tested. We suggest that ST3 gene expression, which was also observed in fibroblasts during cutaneous scar formation, corresponds to a normal wound-healing response that has been subverted in carcinomas.     

CH50 and C3 Component of Complement in Hansen''s Disease

Although a variety of complement values have been reported in leprosy, we found no difference in the CH50 and C3 in the sera of 30 normal persons and 233 lepromatous patients. No statistically significant difference was observed in CH50 and C3 values between healthy controls and lepromatous patients taken as a whole or separated into the different types of the disease spectrum (P greater than 0.1). A statistical difference in C3 titers was found between health controls and borderline patients (P less than 0.05 greater than 0.01) but the sample number is too small to be valid. An important number of sera tested had low and an equally important number had high complement values. Sera with high and low values are important because high values are found in acute inflammatory reactions and low values demonstrate complement activation. Discrepancies in reported results are probably due not only to differences in the methods used, storage and limited number of sera tested, but mainly to the stage of the disease and the drug's administration.     

1α,25(OH)2 vitamin D3 increases intracellular calcium in human keratinocytes

Vitamin D3 metabolites have been found to improve psoriasis but their mechanism of action is not clear. Keratinocyte proliferation and differentiation are known to be dependent on calcium concentrations in vitro. The aim of this study was to examine whether 1 alpha,25(OH)2 vitamin D3 had any direct effect on intracellular free calcium concentrations in cultured keratinocytes. A response to 1 alpha,25(OH)2 vitamin D3 was seen in 88% of monolayers of normal human keratinocytes attached to glass coverslips. An increase in intracellular free calcium was seen in 80% of the reactive cultures, with over half the responses occurring within 30 s of exposure to 1 alpha,25(OH)2 vitamin D3 and the remainder occurring within minutes. Responses could be seen at physiological concentrations of 1 alpha,25(OH)2 vitamin D3 and were not blocked by the protein synthesis inhibitor cycloheximide. The response to 1 alpha,25(OH)2 vitamin D3 took the form of rapid transient increases in intracellular free calcium in 29 out of 59 coverslips. The basal intracellular free calcium was calculated to be 245 +/- 47 nM rising to a maximum of 834 +/- 267 nM (mean +/- SEM; n = 20) following exposure to 1 alpha,25(OH)2 vitamin D3. We conclude that 1 alpha,25(OH)2 vitamin D3 acts directly on keratinocytes to increase intracellular free calcium and that this may be relevant to its mechanism of action in psoriasis.     

25-hydroxyvitamin D3 1alpha-hydroxylase splice variants in human skin

There is increasing evidence that the basophil does not only play an important role in acute allergic reactions but also in the pathogenesis of chronic allergic disorders. Here we show that human basophils express melanocortin receptors (MC-Rs) and respond to alpha-melanocyte-stimulating hormone (alpha-MSH) with regulation of proallergic cytokine expression and modulation of basophil activation markers. Using primers against all known MC-R subtypes we demonstrate that the human basophil cell line KU812 expresses MC-1R. Expression of MC-1R on the surface of KU812 cells was confirmed by FACS analysis using an anti-MC-1R antibody. The MC-1R expressed by KU812 cells was functionally active as alpha-MSH induced intracellular cAMP in a dose-dependent manner. Moreover, alpha-MSH abrogated the effect of calcium ionophore A23187 on IL-4 mRNA expression in these cells. The relevance of the above findings was corroborated by showing that MC-1R surface expression is also detectable in basophils of leukocyte suspensions derived from whole human blood. Most interestingly, alpha-MSH was capable of suppressing the inductive effect of fMLP on surface expression of the basophil activation marker CD63 in leukocyte suspensions of atopic individuals. Likewise, alpha-MSH significantly blocked grass pollen-induced up-regulation of CD63 in leukocyte suspensions of patients with grass pollen allergy. Our findings highlight a novel functional dimension of alpha-MSH. In addition, MSH peptides may become a novel future therapeutic avenue in treating human allergic diseases.     

β2 Microglobulin expression in keratoacanthomas and squamous cell carcinoma

The cell surface expression of beta-2-microglobulin (beta 2 M) was investigated in 33 keratoacanthomas (KA) and 58 squamous cell carcinomas (SCC) to determine whether this antigen was expressed to a different extent in these two conditions and, thus, whether this constitutes a reliable and practical test for distinguishing them. Loss of beta 2 M expression was not a reliable feature for distinguishing between KA and SCC and seemed to be related more to the degree of cellular differentiation and maturation, than to malignancy as such.     

Effects of lithium carbonate (Li2CO3) on in-vitro-cultured normal human skin explants

The early morphological changes induced by lithium carbonate, a well-known psoriasis-provoking drug, were studied on cultured skin. Normal human skin from patients undergoing mastectomy was cultured in the presence of 3 mM, 6 mM and 10 mM of Li2CO3 for 4 days. The morphological changes were then evaluated by three observers in a blind manner and their reports were matched and collated. The cultured skin in the presence of Li2CO3 showed cell crowding of keratinocytes in the lower part of the epidermis, indicating epidermal hyperplasia. Another striking finding was intercellular oedema and vacuolar alteration with formation of small cavities in the upper dermis. There was no evidence of parakeratosis or any other histological characteristic of psoriasis, except hyperproliferation of the epidermis. Based on our knowledge of mechanisms of lithium action, we proposed two competitive explanations for its action on the epidermis: i) that lithium acts directly on dividing cells of the epidermis; and ii) that it acts indirectly by altering epidermal barrier function. Although we lack definite proof, we suggest that the observed morphological changes, in particular the non-specific stimulus to epidermal proliferation, are the primary events which initiate the process that will ultimately lead to the development of psoriasis in a predisposed patient.     

Effects of capsaicin, bradykinin and prostaglandin E2 in the human skin

The actions and interactions of putative mediators of inflammation, such as substance P (SP), histamine, bradykinin and prostaglandins (PGE2) were studied in human skin. In addition, the effects of capsaicin were examined as it is known to release (and to deplete) SP and calcitonin gene-related peptide from C-fibres. The flare evoked by bradykinin was abolished by pretreatment with lignocaine (local anesthetic), compound 48/80 (mast-cell histamine liberator), mepyramine (H1-receptor antagonist) and indomethacin (cyclo-oxygenase inhibitor) but was unaffected by atropine and ketanserin (serotonin antagonist). The weal response was not reduced by any of the drugs. The flare evoked by capsaicin was abolished by lignocaine and indomethacin but was unaffected by compound 48/80, mepyramine, atropine and ketanserin. The weal response was reduced by indomethacin. The flare response to bradykinin seems to reflect the activation of C-fibres and associated mast cells, while the flare response to capsaicin seems to reflect the activation of C-fibres only. Repeated injections of capsaicin and bradykinin produced tachyphylaxis (and cross-tachyphylaxis) and greatly reduced the SP-evoked flare. Capsaicin produced tachyphylaxis also after treatment of the skin with a local anaesthetic, suggesting that it develops independently of C-fibre impulse flow. The tachyphylaxis produced by bradykinin and capsaicin seems to reflect the depletion of messenger peptides from the C-fibres. The flare response to SP following capsaicin- or bradykinin-induced desensitization gradually returned to normal after 5-8 weeks. The erythema evoked by PGE2 was reduced by 30% following pretreatment with lignocaine, mepyramine or compound 48/80.(ABSTRACT TRUNCATED AT 250 WORDS)     

基底细胞癌和鳞状细胞癌皮损中Smad2、Smad3和Smad4 mRNA表达下调

目的：检测转化生长因子β（TBF-β）/Smad信号转导途径中Smad2、Smad3和Smad4mRNA在基底细胞癌（BCC）和鳞状细胞癌（SCC）中的表达水平。方法：应用反转录一实时定量聚合酶链式反应（PCR）方法分别检测BCC、SCC与正常对照皮肤中Smad2、Smad3和Smad4mRNA的表达情况。结果：BCC和SCC皮损中Smad2、Smad3和Smad4mRNA的表达水平均显著低于正常人对照皮肤。结论：皮肤BCC和SCC中Smad2、Smad3和Smad4表达下调可直接或间接导致TGF-β抑制上皮细胞异常增殖和转化的作用受阻，从而有助于上述表皮肿瘤的形成和发展。     

脂溢性角化病、基底细胞癌和鳞状细胞癌中几种Smad蛋白质表达的检测

目的：探讨转化生长因子（TGF）-β信号转导途径中Smad1、Smad2、Smad3（Smad1／2／3）,磷酸化Smad2,磷酸化Smad3（p-Smad2／3）Smad4蛋白在脂溢性角化病、基底细胞癌和鳞状细胞癌中的表达特点及其意义。方法：采用EliVision^TMplus免疫组化技术分别检测脂溢性角化病、基底细胞癌、鳞状细胞癌以及正常对照皮肤中Smad1／2／3、p-Smad2／3、和Smad4的表达情况。结果：Smad1／2／3、p-Smad2／3和Smad4蛋白在脂溢性角化病、基底细胞癌和鳞状细胞癌中的表达较正常表皮显著降低。结论：脂溢性角化病、鳞状细胞癌和基底细胞癌中Smadl／2／3、p-Smad2／3和Smad4蛋白表达降低可能通过阻断TGF—B信号转导,有助于上述表皮肿瘤的形成和发展。     

T4/T8 ratio and absolute T4 cell numbers in different clinical stages of Kaposi''s sarcoma in AIDS

Thirty-seven men (36 homosexual or bisexual and one heterosexual) with epidemic Kaposi's sarcoma and underlying HIV infection were followed up over a period of up to 32 months. Fourteen patients (38%) died, with a median survival time of 7.2 months after the diagnosis of AIDS. Seventeen patients (46%) presented with one or more opportunistic infections, mostly Pneumocystis carinii pneumonia. Eighteen patients (49%) had lymphadenopathy syndrome according to the definition of the CDC. Using the Laubenstein-classification of Kaposi's sarcoma, all patients either remained stable or deteriorated, improvement was never observed. Absolute T4 lymphocyte counts and the T4/T8 ratio were not related to the disease stage. With the onset of B symptoms (systemic symptoms), however, the absolute T4 numbers and the T4/T8 ratio markedly decreased. Delayed type hypersensitivity also showed no relationship to the clinical stages of Kaposi's sarcoma. Thus, the clinical progression of Kaposi's sarcoma lesions seems to be largely independent of the immunological parameters investigated. However, the onset of B symptoms was observed to be related to changes in immune status.     

Identification of CD4+, 2H4+ (T8γ+) suppressor-inducer cells in normal human epidermis and superficial dermis

Immunohistological staining of frozen sections of normal human skin demonstrated the presence of significant numbers of mononuclear cells expressing novel epitopes associated with CD4-positive suppressor-inducer functions. The cells were located around superficial vessels and within the basal layers of the epidermis and hair follicles. The antigen identified by the various antibodies has been shown to be functionally important in the induction of various suppressor cells capable of abrogating B cell responses to pokeweed mitogen. The presence in the skin of cells with possible down-regulatory functions in the immune response may be significant with respect to surveillance against neoplasms and control of appropriate responses to infectious agents.     

The intradermal effects of the H3 receptor agonist R α methylhistamine in human skin

We have investigated the possible existence of the H₃ histamine receptor in human skin with the highly selective ligands R α methylhistamine (RAMHA) (H₃ agonist) and thioperamide (H₃ antagonist). We compared the intradermal effects of RAMHA with histamine, and studied their potential modulation by the H₁ antagonist terfenadine, and H₂ antagonist cimetidine. The effects of RAMHA and thioperamide on codeine phosphate-, substance P- and histamine-induced weal and flare responses were also studied. RAMHA produced dose-related weal and flare responses that were approximately 10- and fivefold less, respectively, than responses to histamine. Flare responses to RAMHA were significantly inhibited by oral terfenadine ( P  < 0.05). Weal and flare responses to histamine after oral cimetidine showed much intersubject variation, and cimetidine did not significantly alter either RAMHA- or histamine-induced weal and flare responses. Codeine phosphate-, substance P- and histamine-induced responses were not significantly affected by concurrent administration of RAMHA. Thioperamide was not found to influence codeine phosphate-, substance P-, RAMHA- or histamine-induced effects. RAMHA induces vascular (weal and flare) responses in human skin, and these responses are partially inhibited by terfenadine. There is a trend for RAMHA to have an additive effect to the weal induced by substance P and histamine, although our results largely do not reach statistical significance. Thioperamide does not affect the vascular responses to RAMHA, codeine phosphate, histamine or substance P. We cannot conclude that the effects of RAMHA are induced by H₃ receptors on cutaneous endothelial or mast cells.