Glucocorticoids inhibit the expression and action of most cytokines. This is part of the in vivo feed-back system between inflammation-derived cytokines and CNS-adrenal produced corticosteroids with the probable physiological relevance to balance parts of the host defence and anti-inflammatory systems of the body. Glucocorticoids modulate cytokine expression by a combination of genomic mechanisms. The activated glucocorticoid-receptor complex can (i) bind to and inactivate key proinflammatory transcription factors (e.g. AP-1, NF kappa B). This takes place at the promotor responsive elements of these factors, but has also been reported without the presence of DNA; (ii) via glucocorticoid responsive elements (GRE), upregulate the expression of cytokine inhibitory proteins, e.g. I kappa B, which inactivates the transcription factor NF kappa B and thereby the secondary expression of a series of cytokines; (iii) reduce the half-life time and utility of cytokine mRNAs. In studies with triggered human blood mononuclear cells in culture, glucocorticoids strongly diminish the production of the 'initial phase' cytokines IL-1 beta and TNF-alpha and the 'immunomodulatory' cytokines IL-2, IL-3, IL-4, IL-5, IL-10, IL-12 and IFN-gamma, as well as of IL-6, IL-8 and the growth factor GM-CSF. While steroid treatment broadly attenuates cytokine production, it cannot modulate it selectively, e.g. just the TH0, the TH1 or the TH2 pathways. The production of the 'anti-inflammatory' IL-10 is also inhibited. The exceptions of steroid down-regulatory activity on cytokine expression seem to affect 'repair phase' cytokines like TGF-beta and PDGF. These are even reported to be upregulated, which may explain the rather weak steroid dampening action on healing and fibrotic processes. Some growth factors, e.g. G-CSF and M-CSF, are only weakly affected. In addition to diminishing the production of a cytokine, steroids can also often inhibit its subsequent actions. Because cytokines work in cascades, this means that steroid treatment can block expression of the subsequent cytokines. The blocked cytokine activity does not depend on a reduced cytokine receptor expression; in fact available in vitro investigations show that while the cytokine expression is blunted, its receptor is upregulated. The cellular studies presented here may represent the maximum potential of steroids to modulate cytokine expression in human mononuclear cells. It remains to be determined by clinical-experimental studies how effective cytokine modulation can be achieved in situ in inflamed bowel by systemic or by topical steroid therapy. Such studies may also answer whether a blocked cytokine production/action is the key or just a secondary mechanism behind the unique efficacy of steroids in active inflammatory bowel disease.

To assess the manifestation and location of airway inflammation in smokers with chronic bronchitis (CB) or chronic obstructive pulmonary disease (COPD), we lavaged the airways of 12 smokers with CB and 11 smokers with COPD and coexisting CB (OCB). For comparison, the airways of 5 asymptomatic smokers (AS) and 10 healthy nonsmokers (HNS) were lavaged. In all cases, the first lavage aliquot, labeled "bronchial lavage" (BL), was processed separately from the four subsequent aliquots, which were combined and labeled "bronchoalveolar lavage" (BAL). The composition of BL and BAL fluids indicate an ongoing inflammatory process in the airways of all three groups of smokers. CB patients with obstruction had significantly lower concentrations of inflammatory cells in the BL and BAL fluids compared with subjects with nonobstructed CB. Furthermore, airway obstruction, indicated by a reduced FEV1, was significantly correlated with the concentrations of glutathione (p < 0.001), myeloperoxidase (MPO; p < 0.01), and eosinophil cationic protein (ECP; p < 0.01) in BAL fluids. Taken together, these findings suggest that the manifestations of inflammation present in the airways of smokers with CB are different in those who have developed obstruction compared with those who have not.

The effect of formoterol, alone and in combination with budesonide, upon tumour necrosis factor-a stimulated (10 ng?mL -1 ) human bronchial epithelial cells was investigated.Addition of formoterol (¢10 -10 M) reduced granulocyte macrophage-colony stimulating factor (GM-CSF) levels, as assessed by enzyme-linked immunosorbent assay, by 40 -50% and increased interleukin (IL)-8 levels by y50%. The effects of formoterol were long lasting (23 h). Budesonide (10 -8 M) reduced the amounts of both cytokines (GM-CSF and IL-8) by 40%. Simultaneous addition of formoterol and budesonide reduced GM-CSF levels y75%, while IL-8 levels were decreased y40%, similar to the reduction obtained with budesonide alone. The glucocorticoid receptor (GR) antagonist RU486 did not influence the effect of formoterol, suggesting no involvement of the GR. Formoterol rapidly induced an elevation in intracellular cyclic adenosine monophosphate, which was reduced in the presence of propranolol. In addition, the alterations in cytokine secretion induced by formoterol could be fully blocked by propranolol, demonstrating that these effects are b 2 -receptor mediated.In conclusion, the combination of budesonide and formoterol reduces the secretion of granulocyte macrophage-colony stimulating factor to basal levels and counteracts the capacity of formoterol alone to induce interleukin-8 production, modulations which may facilitate improved asthma control.

Topical anti-inflammatory (cutaneous "vasoconstriction") and systemic glucocorticoid (depression of plasma cortisol and changes in differential WBC count) potencies of the two glucocorticoids budesonide and beclomethasone dipropionate (BDP) were compared in human volunteers. After topical application, budesonide was 2-3 times more potent than BDP in inducing "vasoconstriction". After oral administration, on the other hand, budesonide was 2-4 times less potent than BDP in depressing plasma cortisol and changing the total or differential WBC. After inhalation, too, significant differences in favour of budesonide were noted, but the divergence between the drugs was less pronounced. The improved relationship between the topical and systemic glucocorticoid effects of budesonide makes it a promising alternative for aerosol treatment in asthma.

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