Liver-spleen axis: Intersection between immunity, infections and metabolism

Abstract

Spleen has been considered a neglected organ so far, even though is strictly linked to liver. The spleen plays an important role in the modulation of the immune system and in the maintenance of peripheral tolerance via the clearance of circulating apoptotic cells, the differentiation and activation of T and B cells and production of antibodies in the white pulp. Moreover, splenic macrophages are able to remove bacteria from the blood and protect from sepsis during systemic infections. We review the spleen function and its assessment in humans starting from the description of spleen diseases, ranging from the congenital asplenia to secondary hyposplenism. From the literature data it is clear that obesity in humans affects different compartments of immune system, even thought there are still few data available on the implicated mechamisms. The intent is to enable clinicians to evaluate the newly recognized role of metabolic and endocrine functions of the spleen with special emphasis to obesity and nonalcoholic fatty liver disease in the context of the available literature. Moreover, understanding the spleen function could be important to develop appropriate prevention strategies in order to counteract the pandemia of obesity. In this direction, we suggest spleen longitudinal diameter at ultrasonography, as simple, cheap and largely available tool, be used as new marker for assessing splenic function, in the context of the so-called liver-spleen axis.

The Spleen Promotes the Secretion of CCL2 and Supports an M1 Dominant Phenotype in Hepatic Macrophages During Liver Fibrosis

“…4). These results suggest that crosstalk may exist between spleen and liver monocyte/macrophage subsets through selective chemokine/cytokine release, further highlighting the existence of a spleen-liver axis [16]. To our knowledge, our study is the first to highlight the interaction between splenic and hepatic macrophages via chemokine secretion and monocyte recruitment during liver fibrosis.…”

“…Given the anatomical proximity between the spleen and liver via the portal vein as well as the frequent involvement of splenic abnormalities in liver diseases, a "liver-spleen axis" has been proposed [15,16]. Clinically, liver cirrhosis is often accompanied by splenomegaly and hypersplenism.…”

Influence of splenorenal shunt on long-term outcomes in cirrhosis

“…The role of spleen is complicated, modulation of the immune system, and maintenance of the physiological environment by filtering old/damaged cells and bacteria [26]. Furthermore, metabolic, endocrine, and hemodynamic functions of the spleen are gaining attention with a certain linkage between liver and spleen [26,27]. In this regard, a presence of SRS may affect the interaction between the two organs, resulting in the poor liver function.…”

“…Furthermore, the incidence of decompensation was higher in cases with advanced SRS assessed by the diameter and flow volume. The role of spleen is complicated, modulation of the immune system, and maintenance of the physiological environment by filtering old/damaged cells and bacteria [26]. Furthermore, metabolic, endocrine, and hemodynamic functions of the spleen are gaining attention with a certain linkage between liver and spleen [26,27].…”

Exposure to stimulatory CpG oligonucleotides during gestation induces maternal hypertension and excess vasoconstriction in pregnant rats

“…The spleen plays an important role in the modulation of the immune system and spleen enlargement is often attributed to overac- tivity such as that seen during a bacterial infection (37). Accordingly, spleen weights may be used as markers of overactivity of the immune system (37).…”