Effects of glucocorticoids on polyamine metabolism in liver and spleen of guinea pig during sensitization

Effects of dexamethasone and Salvia miltiorrhizae on the small intestine and immune organs of rats with severe acute pancreatitis

To observe the protecting effects and mechanisms of Dexamethasone and Salviae miltiorrhizae on intestinal mucosa and immune organs (spleen, thymus and lymph node) in rats with severe acute pancreatitis (SAP). The rats were randomly divided into sham-operated, model control, Dexamethasone treated group and Salviae miltiorrhizae treated group. At 3, 6 and 12 h after operation, the mortality rate, pathological changes of intestinal mucosa and immune organs as well as the contents of serum PAF, IL-1 beta and sIL-2R were observed, respectively. The mortality rate and the contents of PAF (at 3 and 6 h), IL-1 beta (at all time points) and sIL-2R (at 3 and 6 h) as well as the pathological scores of thymus (at all time points) and spleen (at 3 h) in Dexamethasone treated group were significantly lower than those in model control groups (P < 0.05). The contents of PAF (at 3 and 12 h), IL-1 beta (at 6 and 12 h) and sIL-2R (at 3 and 6 h) as well as the pathological scores of thymus (at all time points) and spleen (at 3 and 12 h) in Salviae miltiorrhizae treated group were markedly lower than those in model control groups (P < 0.05). Since both Dexamethasone and Salvia miltiorrhizae can reduce the contents of serum PAF, sIL-2R and IL-1 beta, mitigate the pathological changes in the small intestine, spleen and thymus and reduce the mortality rate of SAP rats, they show good therapeutic effects on SAP rats.

Metabolic correlations of glucocorticoids and polyamines in inflammation and apoptosis

Glucocorticoid hormones (GC) are essential in all aspects of human health and disease. Their anti-inflammatory and immunosuppressive properties are reasons for therapeutic application in several diseases. GC suppress immune activation and uncontrolled overproduction and release of cytokines. GC inhibit the release of pro-inflammatory cytokines and stimulate the production of anti-inflammatory cytokines. Investigation of GC's mechanism of action, suggested that polyamines (PA) may act as mediators or messengers of their effects. Beside glucocorticoids, spermine (Spm) is one of endogenous inhibitors of cytokine production. There are many similarities in the metabolic actions of GC and PA. The major mechanism of GC effects involves the regulation of gene expression. PA are essential for maintaining higher order organization of chromatin in vivo. Spermidine and Spm stabilize chromatin and nuclear enzymes, due to their ability to form complexes with negatively charged groups on DNA, RNA and proteins. Also, there is an increasing body of evidence that GC and PA change the chromatin structure especially through acetylation and deacetylation of histones. GC display potent immunomodulatory activities, including the ability to induce T and B lymphocyte apoptosis, mediated via production of reactive oxygen species (ROS) in the mitochondrial pathway. The by-products of PA catabolic pathways (hydrogen peroxide, amino aldehydes, acrolein) produce ROS, well-known cytotoxic agents involved in programmed cell death (PCD) or apoptosis. This review is an attempt in the better understanding of relation between GC and PA, naturally occurring compounds of all eukaryotic cells, anti-inflammatory and apoptotic agents in physiological and pathological conditions connected to oxidative stress or PCD.

Production of cachexia mediators by Walker 256 cells from ascitic tumors

In neoplasic cachexia, chemical mediators seem to act as initiators or perpetuators of this process. Walker 256 cells, whose metabolic properties have so far been little studied with respect to cancer cachexia, are used as a model for the study of this syndrome. The main objective of this research was to pinpoint the substances secreted by these cells that may contribute to the progression of the cachectic state. Since inflammatory mediators seem to be involved in the manifestation of this syndrome, the in vitro production of nitric oxide (NO), cytokines (tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6)), and prostaglandin E2 (PGE2) was evaluated in Walker 256 cells isolated from ascitic tumors. After 4 or 5 h, a significant increase in NO production was observed (2.55 +/- 1.56 and 4.05 +/- 1.99 nmol NO per 10(7) cells, respectively). When isolated from a 6-day-old tumor, a significantly lower production of IL-6 and higher production of TNF-alpha than in cells from a 4-day-old tumor were observed, indicating a relationship between the production of cytokines and the time of tumor development after implantation. Considerable production of PGE(2) by Walker 256 cells isolated from the 6-day-old tumor was also observed. Polyamines were also determined in Walker 256 cells. Levels of putrescine, spermidine, and spermine did not show significant differences in tumors developed during 4 or 6 days. Direct evidence of the release of proinflammatory cytokines and PGE2 by Walker 256 cells suggests that these mediators can drive the cachectic syndrome in the host, the effect being dependent on tumor development time.

Glucocorticoids and oxidative stress

Glucocorticoids (GC) are used widely for the treatment of patients with various disorders, including autoimmune diseases, allergies, and lymphoproliferative disorders. Glucocorticoid therapy is often limited by several adverse reactions associated with GC excess. Excess GC can elicit a variety of symptoms and signs, including growth retardation in children; immunosuppression; cardiovascular disorders like hypertension and atherosclerosis; osteoporosis; myopathy; and diabetes mellitus. Currently, attention is focused on oxidative stress as one of the major determinants of endothelial dysfunction and cardiovascular senescence. The main reason for all unwanted effects of GC is that dexamethasone induces the overproduction of reactive oxygen species, causing dysregulation of physiological processes. Humans and animals with GC-induced hypertension exhibit reduced nitric oxide levels; patients with excess GC levels also suffer from depression as a consequence of low levels of serotonin and melatonin. The common cofactor for the production of these vasoactive molecules is tetrahydrobiopterin (BH4), which is required for nitric oxide synthesis.