Theoretically, matrix breakdown in non-renal tissues during sepsis could contribute to circulating endostatin levels.
Also, endothelial cells were postulated to be an alternative source of kisspeptin, possibly contributing to circulating plasma levels or acting in a local paracrine fashion.
Extrahepatic sources can also contribute to circulating levels of FVIII, as demonstrated by the surprisingly high residual FVIII plasma levels in dogs transplanted with haemophiliac livers [14].
These results suggest that GH/IGF-I may be important in maintaining ß cell function, which is supported by the observation that the level of whole pancreatic INS-2 mRNA, the primary transcript contributing to circulating insulin in mice, was significantly suppressed by AOiGHD (Fig. 4C).
The cellular source(s) and molecular species that contribute to circulating RANKL are currently unknown.
These results support previous findings (10– 12) that renal elimination contributes to circulating concentrations of this adipokine.
The complexity of factors contributing to circulating CEA is discussed in the light of our findings.
Furthermore, these data support the hypothesis that chondrocytes and cells of the subchondral bone may contribute to circulating sclerostin.
Since different cell types can contribute to circulating miRNA levels, and since hyperglycemia is expected to have different effects on different cell types, contributing to the circulating miRNA pool, miRNA expression is necessarily different in PBMCs and serum.
Furthermore, recent studies show that irisin is not only a myokine but also an adipokine, both muscle and adipose tissue contribute to circulating irisin [ 24, 25].
