By: Jasper de Jong

Title: Lessons we can learn from serum about adipogenesis


To understand the processes that regulate the formation of fat cells, various cell
models are employed. Immortalized mouse 3T3 cells form a widely used model to
study the differentiation process of adipocytes. More costly, but probably biologically
more relevant, are primary cultures of preadipocytes isolated from a range of different
adipose tissues.
A common factor in these cultures of various adipogenic cells – and in cell culture in
general - is the use of serum as a source of required factors to allow for growth of
cells in vitro. The composition of sera derived from different species or
developmental stages can vary substantially. The choice of serum might therefore
affect the behavior of cultured adipose cells. These differences in sera create
experimental variation, but they can also teach us about how its composition
influences the development of adipose cells.
Various studies have reported pro-adipogenic and anti-adipogenic effects of serum.
The effects vary with the species and developmental stage of the animal from which
serum is obtained, but it has also been described that different adipose cell models
respond differently to serum.
Serum choice thus influences experimental outcomes, but this could be used to further
our understanding of how serum-derived factors influence the adipogenic process.
Several studies have aimed at isolating regulatory factors from serum, but very few
have succeeded in coming to final conclusions about the identity of such factors.
Additionally, various agents (both natural and synthetic) have been described that
positively influence adipocyte differentiation and are therefore often included in
adipose culture protocols.
The serum-derived molecules that were shown to regulate adipogenesis displayed
various characteristics. Therefore, it is clear that serum still holds lots of information
about regulators of adipogenesis that still remains to be uncovered.