Altered leucocyte trafficking and suppressed tumour necrosis factor alpha release from peripheral blood monocytes after intra-articular glucocorticoid treatment

Abstract

Objectives: A generalised transient improvement may follow intra-articular administration of glucocorticoids to patients with inflammatory arthropathy. This may represent a systemic anti-inflammatory effect of glucocorticoid released from the joint, mediated through processes such as altered leucocyte trafficking or suppressed release of pro-inflammatory cytokines. Patients, who had received intra-articular injections of glucocorticoids were therefore studied for evidence of these two systemic effects.

Methods: Patients with rheumatoid arthritis were studied. Peripheral blood leucocyte counts, tumour necrosis factor alpha (TNF alpha) release by peripheral blood monocytes, blood cortisol concentrations, and blood methylprednisolone concentration were measured for 96 hours after intra-articular injection of methylprednisolone acetate.

Results: Measurable concentrations of methylprednisolone were present in blood for up to 96 hours after injection. Significant suppression of the hypothalamic-pituitary-adrenal axis persisted throughout this time. Altered monocyte and lymphocyte trafficking, as evidenced by peripheral blood monocytopenia and lymphopenia, was apparent by four hours after injection and resolved in concordance with the elimination of methylprednisolone. Granulocytosis was observed at 24 and 48 hours. Release of TNF alpha by endotoxin stimulated peripheral blood monocytes was suppressed at four hours and thereafter. Suppression was maximal at eight hours and was largely reversed by the glucocorticoid antagonist, mifepristone.

Conclusions: After intra-articular injection of methylprednisolone, blood concentrations of glucocorticoid are sufficient to suppress monocyte TNF alpha release for at least four days and to transiently alter leucocyte trafficking. These effects help to explain the transient systemic response to intra-articular glucocorticoids. Suppression of TNF alpha is principally a direct glucocorticoid effect, rather than a consequence of other methylprednisolone induced changes to blood composition.

Figures

Figure 1

Methylprednisolone and cortisol concentrations in peripheral blood over 96 hours after intra-articular administration of methylprednisolone. At each time point from four hours to 96 hours, the plasma cortisol concentration was significantly lower than the pre-dose value (p 

Figure 2

Lymphocyte, monocyte, and granulocyte numbers in peripheral blood over 96 hours after intra-articular administration of methylprednisolone. Significant changes in cell numbers from pre-dose values (p 

Figure 3

TNFα concentrations (mean (SEM)) in LPS stimulated peripheral blood samples reconstituted with plasma, which was collected before intra-articular injection with methylprednisolone and for 96 hours thereafter. Concentrations of TNFα were significantly lower in all post-dose samples than in the pre-dose samples (* p 

Figure 4

Blood samples taken eight hours after injection release significantly less TNFα upon LPS stimulation (8 hour + LPS) than samples collected 14 days later (control + LPS), when all methylprednisolone had been eliminated (* p = 0.01, n = 6, Student's t test). When the glucocorticoid antagonist, mifepristone (50 µM) is added to the eight hour sample, TNFα release increases significantly to concentrations comparable with the control sample († p = 0.004, compared with the eight hour sample, without mifepristone; n = 6, Student's t test). Mifepristone itself does not influence TNFα release from the unstimulated day 14 sample (compare control and mifepristone bars).