Somatostatin inhibits pro-inflammatory cytokine secretion from rat hepatic stellate cells

Background/aims: Activated hepatic stellate cells (HSCs) have been implicated in hepatic fibrosis. Somatostatin (SOM) has an immunomodulatory role. The aim of this study was to assess the secretion of pro-inflammatory cytokines by HSCs and to determine the effect of SOM on the secretion of these mediators. Methods: Activated rat HSCs were evaluated for their secretion of IL-1 beta, IL-8, and TNF-alpha using ELISA. RNA protection assay was used to determine cytokine mRNA levels. The expression of chemokine and cytokine mRNA and the secretion of these mediators were assessed following incubation with SOM or octreotide. Results: HSCs spontaneously secreted IL-1 beta, IL-8, and TNF-alpha. This secretion was augmented following stimulation by IL-1 beta and TNF-alpha. SOM inhibited the spontaneous and TNF-alpha-induced secretion of IL-1 beta, IL-8, and TNF-alpha and suppressed the expression of IL-1 beta and TNF-alpha mRNA. Octreotide suppressed the secretion of IL-1 beta and IL-8. Conclusions: These observations indicate that SOM exerts an inhibitory immunomodulatory effect on HSCs.