Objectives: To evaluate whether anti-TNF-α therapy (infliximab) administration alters circulating levels of ghrelin, an anti-inflammatory gastric peptide. We also assessed possible associations of circulating ghrelin concentrations with CRP and ESR levels, metabolic syndrome, demographic characteristics and other adipokines in ankylosing spondylitis (AS) patients.
Methods: We studied 30 consecutive non-diabetic AS patients, without history of cardiovascular (CV) events, on periodical treatment with infliximab. Serum ghrelin levels were determined immediately prior to and after an infliximab infusion. Correlations of ghrelin serum levels with disease activity, systemic inflammation and metabolic syndrome were assessed. Potential changes in ghrelin concentration following an infusion of infliximab were analysed.
Results: We observed a negative correlation between ghrelin concentration and insulin resistance (HOMA-IR immediately before infliximab infusion- at time 0 and at the end of infliximab infusion- at time 120') (r=-0.496; p=0.01 at time 0; r=-0.393; p=0.047 at time 120', respectively). We also found a positive correlation with insulin sensitivity (QUICKI) (r=0.415; p=0.035 at time 0; r=0.465; p=0.017 at time 120'). A correlation was found between ghrelin and resistin prior to infliximab infusion (r=0.429; p=0.046), and a negative correlation between serum ghrelin levels at time 0 and triglycerides (r=-0.416; p=0.035). No differences in ghrelin levels according to specific clinical features of the disease were seen. A single infliximab infusion led to mild but not significant increase in ghrelin serum concentration.
Conclusions: In AS patients undergoing periodical treatment with anti-TNF-α monoclonal antibody-infliximab a link between insulin resistance and serum ghrelin concentration was observed.