Effects of estrogen peripheral metabolism in rheumatoid arthritis

It is well known that the immune reactivity is modulated by gender. In fact, women show a more effective immune response as well as a more frequent development of autoimmune diseases. In particular, 17b-estradiol (E2) in patients with systemic inflammatory diseases leads to an higher production of IgG and IgM in peripheral blood mononucleated cells (PBMC) and the secretion of metalloproteinases and IL-6 by synovial fibroblasts. The effect of E2 seems to be partially related to its concentration. In fact, at the physiological concentration, E2 seems to exert a pro-inflammatory effect, while at pharmacological concentrations shows anti-inflammatory effects. Steroid hormones can be converted in downstream hormones along defined pathways. The conversion of dehydroepiandrosterone (DHEA) in peripheral macrophages leads to the androgen production. Subsequently the enzyme aromatase converts androgens in estrogens, and its activity is increased by some inflammatory cytokines such as IL-1b, IL-6 and TNF-a. In the synovial fluids of rheumatoid arthritis (RA) patients the levels of estrogens result significantly increased compared with controls, showing the consequence of this unbalanced steroid metabolism. Furthermore, the metabolism of estrogens leads to some downstream hydroxylated metabolites, that are not waste products, but still active molecules in the inflammatory response. In fact, it has been found that synovial fluids of RA patients present a different ratio of 16-hydroxylated estrogen metabolites/ 2-hydroxylated metabolites, confirming that also the unbalanced metabolism of estrogens and not only the estrogen concentration seems to be related to the development and worsening of rheumatoid arthritis

[17beta-Estradiol and testosterone influence the mRNA expression and the time course of inflammatory cytokines in activated human monocytic cell line (THP-1)].

Objective: The aim of this study was to evaluate the effects of 17b-estradiol (E2) and testosterone (T) on the mRNA expression of IL-1b, IL-6, TNF-a and TGF-b in cultured human monocytic cells (THP-1) after INF-g activation. Methods: THP-1 were cultured with E2 and T (10 nM) for 24 hs and then activated with INF-g (500 U/ml), during different periods of time (1, 3, 6, and 12 hs). After total RNA extraction, all samples were analyzed by multiple RT-PCR to detect mRNA expression of the selected cytokines. Results: Cells cultured without hormonal treatment expressed IL-1b mRNA after 1 h; on the contrary TNF-a, TGF-b and IL-6 mRNA were expressed only after 3 hs. At 6 and 12 hs only IL-6 mRNA was still expressed. Interestingly, cells cultured with testosterone never expressed IL-1b nor TNF-a mRNA and showed an IL-6 mRNA expression similar to the untreated controls at 3, 6 and 12 hours. On the contrary, cells treated with E2 showed the expression of all cytokines at 3 and 12 hs, and in general showed an higher expression of all the analyzed cytokines mRNA when compared to the other conditions. Conclusions: This study suggests that sex hormones may modulate the cytokine mRNA expression in the inflammatory cells. In fact, T inhibits TNF-a production at all the tested times, whereas E2 seems to accelerate and to enhance the inflammatory response. Therefore, the altered sex hormone ratio, as observed in the synovial fluid of RA patients (high E2/low T), might contribute to the occurrence and last of synovitis

Androgen metabolism and inhibition of interleukin-1 synthesis in primary cultured human synovial macrophages

The presence of androgen receptors on synovial macrophages in human normal and rheumatoid synovial tissues has been described previously. It is now reported that primary cultured human macrophages obtained from normal and rheumatoid synovia express functional androgen receptors. We have investigated the capacity of cultured macrophages to metabolize androgens and have found that these cells were capable of metabolizing testosterone to the bioactive metabolite dihydrotestosterone. Therefore, macrophages contain the key enzymes of steroidogenesis, in particular the 5α-treductase. Furthermore, interleukin-1β production by primary cultured rheumatoid macrophages was analysed, following exposure to physiological concentrations of testosterone (10−8 M). A significant decrease of IL-1β levels in conditioned media after 24 h (p < 0.05) was observed. It is concluded that androgens may act directly on human macrophages and may interfere with some of their functions via receptor-dependent mechanisms

Myostatin mediates abdominal aortic atherosclerosis progression by inducing vascular smooth muscle cell dysfunction and monocyte recruitment

Myostatin (Mstn) is a skeletal muscle growth inhibitor involved in metabolic disorders and heart fibrosis. In this study we sought to verify whether Mstn is also operative in atherosclerosis of abdominal aorta. In human specimens, Mstn expression was almost absent in normal vessels, became detectable in the media of non-progressive lesions and increased with the severity of the damage. In progressive atherosclerotic lesions, Mstn was present in the media, neointima, plaque shoulder and in infiltrating macrophages. Mstn co-localized with \uce\ub1-smooth muscle actin (\uce\ub1-SMA) staining and with some CD45+ cells, indicating Mstn expression in VSMCs and bloodstream-derived leukocytes. In vitro, Mstn was tested in VSMCs and monocytes. In A7r5 VSMCs, Mstn downregulated proliferation and Smoothelin mRNA, induced cytoskeletal rearrangement, increased migratory rate and MCP-1/CCR2 expression. In monocytes (THP-1 cells and human monocytes), Mstn acted as a chemoattractant and increased the MCP-1-dependent chemotaxis, F-actin, \uce\ub1-SMA, MCP-1 and CCR2 expression; in turn, MCP-1 increased Mstn mRNA. Mstn induced JNK phosphorylation both in VSMCs and monocytes. Our results indicate that Mstn is overexpressed in abdominal aortic wall deterioration, affects VSMCs and monocyte biology and sustains a chronic inflammatory milieu. These findings propose to consider Mstn as a new playmaker in atherosclerosis progression

Effects of estrogen peripheral metabolism in rheumatoid arthritis

It is well known that the immune reactivity is modulated by gender. In fact, women show a more effective immune response as well as a more frequent development of autoimmune diseases. In particular, 17b-estradiol (E2) in patients with systemic inflammatory diseases leads to an higher production of IgG and IgM in peripheral blood mononucleated cells (PBMC) and the secretion of metalloproteinases and IL-6 by synovial fibroblasts. The effect of E2 seems to be partially related to its concentration. In fact, at the physiological concentration, E2 seems to exert a pro-inflammatory effect, while at pharmacological concentrations shows anti-inflammatory effects. Steroid hormones can be converted in downstream hormones along defined pathways. The conversion of dehydroepiandrosterone (DHEA) in peripheral macrophages leads to the androgen production. Subsequently the enzyme aromatase converts androgens in estrogens, and its activity is increased by some inflammatory cytokines such as IL-1b, IL-6 and TNF-a. In the synovial fluids of rheumatoid arthritis (RA) patients the levels of estrogens result significantly increased compared with controls, showing the consequence of this unbalanced steroid metabolism. Furthermore, the metabolism of estrogens leads to some downstream hydroxylated metabolites, that are not waste products, but still active molecules in the inflammatory response. In fact, it has been found that synovial fluids of RA patients present a different ratio of 16-hydroxylated estrogen metabolites/ 2-hydroxylated metabolites, confirming that also the unbalanced metabolism of estrogens and not only the estrogen concentration seems to be related to the development and worsening of rheumatoid arthritis