Similar PAI-1 expression in visceral and subcutaneous fat of postmenopausal women.

Recent studies showed that intraabdominal visceral fat located in the mesenterium and omentum may significantly influence the circulating plasminogen activator inhibitor type 1 (PAI-1). To substantiate this link, we performed analysis of PAI-1 expression in human visceral and subcutaneous adipose tissues in peri- and postmenopausal women. The samples of both visceral and subcutaneous fat from 28 generally healthy women (aged 45-69 years) with a wide range of body mass index (BMI; 22.30-38.67 kg/m2), who underwent surgical operation due to benign ovary and uterine tumours, were obtained. In these samples, expression of mRNAs for PAI-1, tumour necrosis factor alpha (TNFalpha), acyl-CoA synthetase (ACS), and glucose transporter (GLUT-4) was analysed by relative quantitative RT PCR and correlated with plasma PAI-1 antigen. In addition, visceral fat area was measured with computer tomography. Both types of fat tissues contained similar quantities of PAI-1 mRNA, and there was no correlation between plasma PAI-1, measured both by antigen and activity, with either visceral or subcutaneous fat PAI-1 mRNA. Furthermore, there was no significant association between the expression of PAI-1 mRNA and TNFalpha mRNA in tested fat samples. PAI-1 mRNA in both fat tissues was significantly correlated with plasma levels of estradiol (positive correlation) and follicle-stimulating hormone (FSH; negative correlation). Finally, the expression of PAI-1 mRNA was negatively correlated with mRNA of ACS present in both fat tissues. In summary, this study directly indicates that PAI-1 mRNA is similarly expressed in both subcutaneous and visceral fat of peri- and postmenopausal women and its expression strongly depends upon lipid metabolism.

Inhibition of plasminogen activator inhibitor release in endothelial cell cultures by antisense oligodeoxyribonucleotides with a 5'-end lipophilic modification.

A series of conjugates containing residues of lipophilic alcohols covalently bound to 5' end of oligodeoxyribonucleotides targeted against human plasminogen activator inhibitor (PAI-1) mRNA was synthesized via the oxathiaphospholane approach. The highest anti-PAI-1 activity in EA.hy 926 endothelial cell cultures was found for conjugates containing menthyl or heptadecanyl groups linked with an oligonucleotide complementary to a segment of human PAI-1 mRNA. The phosphodiester antisense oligonucleotides, which otherwise exhibit only limited anti-PAI-1 activity, were found to be more active than phosphorothioate oligonucleotides when conjugated to lipophilic alcohol residues. For menthyl conjugates an evidence of antisense mechanism of inhibition was found.

Repeated low-dose ultraviolet (UV) B exposures of humans induce limited photoprotection against the immune effects of erythemal UVB radiation.

BACKGROUND: Exposure of human subjects to ultraviolet (UV) B radiation causes immunosuppression. Most experiments to date have not tested the effects of low daily doses of UVB radiation. OBJECTIVES: To ascertain whether photoprotection against several UV-induced immune effects might develop following repeated exposure. METHODS: Groups of approximately 30 healthy individuals were given whole-body UVB irradiation on each of 10 consecutive days with 0.7 minimal erythema dose, or whole-body irradiation as before followed by a single erythemal UVB dose on a small body area, or irradiated only with a single erythemal UVB dose on a small body area, or were not irradiated. They were sensitized with diphenylcyclopropenone (DPCP) 24 h after the final dose, and skin biopsies collected to assess cytokine mRNA expression and the number of cells with thymine dimers and expression cyclooxygenase (COX)-1 and COX-2. RESULTS: The contact hypersensitivity (CHS) response to DPCP was significantly lower in the three irradiated groups compared with the unirradiated controls, while cutaneous interleukin (IL)-1beta, IL-6, IL-10 and tumour necrosis factor-alpha mRNAs, COX-1 and COX-2 and thymine dimers were all significantly higher. When the single erythemal UVB dose was given following the repeated low exposures, a slight downregulation in cytokine expression and thymine dimer formation was indicated. CONCLUSIONS: The repeated low doses of UVB protected to a limited extent against the effects of an erythemal UVB dose on cytokine expression and thymine dimer formation, but not on CHS or COX enzymes.

Dual regulatory effects of nitric oxide on plasminogen activator inhibitor type 1 expression in endothelial cells.

In this report we compared the mechanism by which nitric oxide (NO), generated exogenously and endogenously, affects the plasminogen activator inhibitor type 1 (PAI-1) expression in endothelial cells. For this purpose, we stimulated the endothelial cell line EA.hy 926 with tumour necrosis factor alpha (TNFalpha) in the presence of the exogenously NO-releasing donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine, or regulators of nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine-methyl ester hydrochloride and substrate L-Arg. Expression of PAI-1 in EA.hy 926 cells was determined by measuring the level of mRNA, using relative quantitative reverse transcriptase PCR, and protein, using ELISA. In addition, we estimated the level of activation of two mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK1/2), in the cells before and after treatment with TNFalpha, in the presence or absence of NO donors and inhibitors. In contrast to exogenously released NO that significantly reduced mostly basal PAI-1 expression, endogenously generated NO by NOS potentiated TNFalpha-induced upregulation of PAI-1 expression. Exogenously and endogenously generated NO causes different effects on activation of the MAPKs ERK1/2 and JNK1/2. Specifically, the SNP-released NO activates only ERK1/2, while endogenously generated NO in a pathway induced by TNFalpha activates both MAPKs. Thus our data indicate that due to different cellular locations and mechanisms of generation, NO may participate in various signalling pathways leading to opposite effects on PAI-1 expression in endothelial cells.