Effects of ghrelin supplementation on the acute phase of Chagas disease in rats

The expression and function of growth hormone secretagogue receptor in immune cells: A current perspective

The orexigenic hormone ghrelin and its receptor, growth hormone secretagogue receptor (GHS-R), have been extensively studied in the last two decades, revealing that ghrelin signaling has important implications in health and disease. Metabolic diseases, such as obesity and diabetes, are often accompanied by low-grade chronic inflammation, that has been coined as "meta-inflammation." Immune cells are key cellular mediators of meta-inflammation, controlling both initiation and resolution of inflammation. Immune cells exhibit dynamic changes in cellular characteristics and functional output in response to the stimuli/insults from their surrounding microenvironment. Emerging evidence shows that ghrelin has an important effect on inflammation, in addition to its well-known effects on metabolism. However, the cellular/molecular mechanism of ghrelin signaling in immunity is largely unknown because the knowledge in regard to the expression and function of GHS-R in immune cells is currently sparse. In this review, we have accumulated the recent findings related to the expression and functions of GHS-R in various immune cells under different physiological and pathological states. This review aims to inspire further investigation of the immunological roles of ghrelin signaling and advance the therapeutic applications of ghrelin signaling in meta-inflammation.

Ghrelin attenuates infectious bursal disease virus-induced early inflammatory response and bursal injury in chicken

Studies demonstrated that chicken ghrelin mRNA was expressed in immune organs of chicken. However, it was not known for its functions in chicken immune system. This study aimed to investigate the effects of ghrelin on infectious bursal disease virus (IBDV)-induced acute inflammatory and bursal injury. Chickens were divided into 4 groups. One group was used as control (“C”). The other three groups incubated with IBDV on the 19th d, of which 2 were injected intraperitoneally with 0.5 nmol (“LG”) or 1.0 nmol (“HG”) ghrelin/100g body weight from 18th to 22nd d, respectively, and one was injected intraperitoneally with PBS (“I”). Results showed that cytokines including interleukin (IL)-6, IL-1β, and IL-8 mRNA expression in I group were upregulated significantly after chickens infected with IBDV from 1 d post-infection (dpi) to 3 dpi (P < 0.05). However, the expression level of IL-6, IL-1β, and IL-8 mRNA in LG and HG groups was 7.3, ∼43.3% as much as that of the I group at 2 dpi and 3 dpi (P < 0.05). Moreover, ghrelin administration attenuated significantly the bursal injury from 1 dpi to 7 dpi and prevents the reduction of bird weight gain at 5 dpi and 7 dpi, which were induced by IBDV (P < 0.05). The results indicated that ghrelin could play an important role in the immune system of chicken.