Biomedical Engineering Reference
In-Depth Information
stretching (Fig.
3
), at least in part. The activation of Rho-Rho-kinase signaling
further enhances inflammatory changes in hypertrophied adipose tissues, leading
to systemic insulin resistance and further induces adipocyte hypertrophy, thereby
as a vicious cycle would be established [
35
]. Systemic treatment of fasudil, a Rho-
kinase inhibitor, ameliorates high-fat diet induced obesity and adipocyte hyper-
trophy in mice [
35
]. Blockade of Rho-Rho-kinase signaling would interrupt the
vicious cycle and thus pharmaceutical intervention of this pathway might be a
therapeutic strategy for obesity and related diseases [
35
,
148
], although the
opposite function of Rho-Rho-kinase signaling in undifferentiated cell populations
(such as ASCs and/or preadipocytes) in adipose tissues might be also taken into
account.
5 In Vivo Application of Mechanical Stimuli to Adipose
Tissues
The mechanosensitivity of adipocytes may not only have an important physio-
logical significance but also be of great value on the application side. Thus, we
briefly mention the implication of mechanical stimuli and adipose tissue in vivo.
Mechanical stimuli acting directly on adipose tissues may activate mechano-
transduction mechanisms in adipocytes/preadipocytes/ASCs, fibroblasts, vascular
cells, nerve cells, and infiltrated macrophages. Examples of these are low-mag-
nitude mechanical signals on obese mice [
149
], and a physiotheraputically-
established mechanical massage device on human female gluteofemoral adipose
tissues [
150
]. The results from these studies indicated that the mechanical signals
significantly affect the development [
149
] and metabolic functions [
149
,
150
]of
adipose tissue as well as the gene expressions therein [
150
], mostly suggesting
reduced adiposity and improvement of metabolic status, although the differential
effects of mechanical stimuli on the heterogeneous cell population of adipose
tissues might be considered. The effects of mechanical loading on adipose tissues
of both experimental animals and human with respect to the treatment approaches
in obesity and related conditions have been extensively reviewed and discussed by
Shoham and Gefen [
10
].
6 Concluding Remarks
It becomes apparent that mechanical stimuli, including stretching, have a signifi-
cant influence on adipocyte differentiation (Table
1
). Although many cellular
signals have been implicated in the mechanotransduction of adipocytes and related
cells (Fig.
3
), the stretch-induced inhibition of adipogenesis via the downregula-
tion of PPARc appears to be a common response in preadipocytes and MSCs. This
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