Glucagon-like peptide 1 improves insulin resistance in vitro through anti-inflammation of macrophages

Glucagon-like peptide 1 (GLP-1), a kind of gut hormone, is used in the treatment of type 2 diabetes (T2D). Emerging evidence indicates that GLP-1 has anti-inflammatory activity. Chronic inflammation in the adipose tissue of obese individuals is a cause of insulin resistance and T2D. We hypothesized that GLP-1 analogue therapy in patients with T2D could suppress the inflammatory response of macrophages, and therefore inhibit insulin resistance. Our results showed that GLP-1 agonist (exendin-4) not only attenuated macrophage infiltration, but also inhibited the macrophage secretion of inflammatory cytokines including TNF-β, IL-6, and IL-1β. Furthermore, we observed that lipopolysaccharide (LPS)-induced macrophage conditioned media could impair insulin-stimulated glucose uptake. This effect was compensated by treatment with the conditioned media from macrophages treated with the combination of LPS and exendin-4. It was also observed that exendin-4 directly inhibited the activation of NF-κB in macrophages. In conclusion, our results indicated that GLP-1 improved inflammatory macrophage-derived insulin resistance by inhibiting NF-κB pathway and secretion of inflammatory cytokines in macrophages. Furthermore, our observations suggested that the anti-inflammatory effect of GLP-1 on macrophages can contribute to GLP-1 analogue therapy of T2D.

Manipulation of cytokine production profiles as a therapeutic approach for immunologic pregnancy loss.

Pregnancy is not as successful as one might think; it can be compromised by several complications such as recurrent spontaneous miscarriage, pre-term delivery, pre-eclampsia etc. Much attention has been paid to the possibility of the maternal immune system mediating deleterious effects on pregnancy. Research conducted during the last two decades has shed much light on cell-mediated immunologic effectors that might underlie these pregnancy complications. Of particular interest are the effects that pro-inflammatory and anti-inflammatory cytokines have on the foetus and placenta, and thus on the success and failure of pregnancy. This review presents evidences that certain cytokine profiles are associated with recurrent miscarriage and pre-term delivery and discusses possible pathways of effector function of cytokines in pregnancy loss and the redirection of cytokine profiles from one that is antagonistic to pregnancy towards one that is conducive to the success of pregnancy. Among the promising agents for the modulation of the Th1/Th2 balance are progestogens like progesterone and dydrogesterone; this review also discusses recent evidence that progestogens are capable of modulating cytokine production patterns in pregnancy loss.

An overview of the effects of annexin 1 on cells involved in the inflammatory process

The concept of anti-inflammation is currently evolving with the definition of several endogenous inhibitory circuits that are important in the control of the host inflammatory response. Here we focus on one of these pathways, the annexin 1 (ANXA1) system. Originally identified as a 37 kDa glucocorticoid-inducible protein, ANXA1 has emerged over the last decade as an important endogenous modulator of inflammation. We review the pharmacological effects of ANXA1 on cell types involved in inflammation, from blood-borne leukocytes to resident cells. This review reveals that there is scope for more research, since most of the studies have so far focused on the effects of the protein and its peptido-mimetics on neutrophil recruitment and activation. However, many other cells central to inflammation, e.g. endothelial cells or mast cells, also express ANXA1: it is foreseen that a better definition of the role(s) of the endogenous protein in these cells will open the way to further pharmacological studies. We propose that a more systematic analysis of ANXA1 physio-pharmacology in cells involved in the host inflammatory reaction could aid in the design of novel anti-inflammatory therapeutics based on this endogenous mediator.

Participação do óxido nítrico no processo inflamatório articular / Nitric oxide participation in the articular inflammatory process

O presente trabalho avalia a participação do óxido nítrico (NO) na fisiopatologia da resposta inflamatória articular. O papel pró-inflamatório deste medidor, tanto no componente vascular quanto no celular foi evidenciado em diferentes modelos experimentais, utilizando animais tratados cronicamente com o inibidor inespecífico de síntese de NO, NG-nitro-L-arginine metil ester (L-NAME, 20mg/Kg/dia/14 dias). Investigamos os mecanismos envolvidos na alteração de parâmetros inflamatórios como: interação leucócito endotélio, expressão de moléculas de adesão, reatividade da microcirculação, parâmetros hemodinâmicos, alterações na permeabilidade vascular, além da interação entre produção de NO e outros mediadores da resposta inflamatória, como eicosanóides, sistema de cininas, citocinas e histamina, bem como influência do tratamento na. hematopoiese e hemograma. Em conjunto, os estudos contribuem para esclarecer o controverso papel do NO no processo inflamatório. /The present study describes the participation of nitric oxide (NO) in the patophisiology of experimental arthritis induced by different antigens through chronicle administration of the unspecific inhibitor of NO synthases NG-nitro-L-arginine metyl ester (L-NAME, 20mg/Kg/day/14 days). The pro-inflammatory effect of NO was observed such as on cellular as on vascular events of the process. The mechanisms involved were assessed by investigations on haematopoeisis and haemogram, leukocyte endothelial interaction, adhesion molecules expression, haemodynamic properties, microvascular reactivity, protein leakage, as well as interaction between NO and eicosanoids, bradykinin, cytokines and histamine production. Together these studies contribute to clarify the controversial role of NO on the inflammatory process...

Effects of oncostatin M on hormone release of rat pituitary cells in primary culture

It has become increasingly clear that cytokines play an important role in modulating neuroendocrine regulation, especially in the secretion of corticotropin (ACTH) in the pituitary. Oncostatin M (OSM), a cytokine of IL-6 family has been reported to increase ACTH secretion and pro-opiomelanocortin (POMC) transcription in murine corticotroph pituitary tumor cells (AtT20 cells). The present study was undertaken to determine the effects of OSM on hormonal release in primary culture of rat pituitary cells. Growth hormone or prolactin release was not affected by OSM. OSM (1 nM) stimulated ACTH release (35.1% increase versus control, p>0.001) in dispersed pituitary cells of rat to a lesser extent than in AtT20 cells. Corticotropin releasing hormone (CRH) (10 nM) also induced a 2.3-fold increase of ACTH secretion (p>0.001), but co-treatment of OSM and CRH did not exhibit any synergistic effect on ACTH secretion. We conclude OSM has a stimulatory effect on ACTH secretion in normal rat pituitary cell cultures, and OSM acts mainly on corticotroph, supporting the potential role of OSM to modulate immune-endocrine regulation in the pituitary.

Effects of oncostatin M on hormone release of rat pituitary cells in primary culture

It has become increasingly clear that cytokines play an important role in modulating neuroendocrine regulation, especially in the secretion of corticotropin (ACTH) in the pituitary. Oncostatin M (OSM), a cytokine of IL-6 family has been reported to increase ACTH secretion and pro-opiomelanocortin (POMC) transcription in murine corticotroph pituitary tumor cells (AtT20 cells). The present study was undertaken to determine the effects of OSM on hormonal release in primary culture of rat pituitary cells. Growth hormone or prolactin release was not affected by OSM. OSM (1 nM) stimulated ACTH release (35.1% increase versus control, p>0.001) in dispersed pituitary cells of rat to a lesser extent than in AtT20 cells. Corticotropin releasing hormone (CRH) (10 nM) also induced a 2.3-fold increase of ACTH secretion (p>0.001), but co-treatment of OSM and CRH did not exhibit any synergistic effect on ACTH secretion. We conclude OSM has a stimulatory effect on ACTH secretion in normal rat pituitary cell cultures, and OSM acts mainly on corticotroph, supporting the potential role of OSM to modulate immune-endocrine regulation in the pituitary.