Release of Inflammatory Mediators by Human Adipose Tissue Is Enhanced in Obesity and Primarily by the Nonfat Cells: A Review

Table 1

Comparison of release of 37 adipokines by fat cells as compared to the other cells in human adipose tissue ranked by fat cell release along with the effect of obesity on their circulating levels in humans.

Adipokine	Release by nonfatcells in pmoles/g	Release by fatcells in pmoles/g	Effect of obesity on circulating levels
FABP-4	590	360	Elevated [16–18]
PGE2	1810*	118*	No data
IL-8	1120*	87*	Elevated [21, 22]
PAI-1	78*	18*	Elevated [19, 23, 24]
MCP-1	74*	9.2*	Elevated [4, 20, 22, 25]
IL-6	66*	5.1*	Elevated [4, 25–31]
Adipsin	26	4.1	Elevated [28, 32]
Adiponectin	6	4.1	Lower [25, 33, 34]
GPX-3	14	3.6	Lower [35]
Leptin	0.1	1.8	Elevated [19, 25, 36]
Amyloid A	1.3	1.6	Elevated [19, 32, 37]
Migration inhibitor factor	2.8	1.0	Elevated [38]
Visfatin/PBEF/Nampt	1.0	0.60	No change [39–41]
CD14	1.6	0.56	No change [42]
ZAG	0.7	0.44	No change [17]
Lipocalin-2	5.4	0.27	No change [42, 43]
Cathepsin S	4.4	0.26	Elevated [44]
RANTES	2.1	0.21	No change [42] but see [25]
IL-1Ra	4.1	0.14	Elevated [36]
Osteoprotegerin	0.1	0.12	No change [42, 45]
HGF	2.8	0.11	Elevated [46]
LPL	0.02	0.080	No change [47]
Haptoglobin	0.08	0.060	Elevated [48]
ICAM-1	0.27	0.056	Elevated [4, 29, 49]
ACE	0.23	0.017	Elevated [50]
IL-10	0.53	0.020	Elevated [28]
VEGF	0.30	0.020	Elevated [51]
VCAM-1	0.46	0.016	Elevated [29]
IL-1$\beta$	0.23	0.013	No data
TNF $\mathit{\alpha }$	0.22	0.012	Elevated [5, 27, 29–31, 52]
TGF- $\mathit{\beta }$ 1	0.17	0.009	Elevated [53]
sTNF RII	0.44	0.007	Elevated [5, 18, 19, 30, 54]
NGF	0.006	0.005	Elevated [55]
VEGFR/sFLT1	0.018	0.002	No change [34]
Resistin	1.8	$<$0.04	No change [56, 57]
$\mathit{C}\mathit{R}\mathit{P}$	$\mathit{0.01}$	$<$ 0.002	Elevated [17, 19, 20, 28, 30, 31, 49, 58]
$\mathit{I}\mathit{L}\mathbf{\text{-}}\mathit{18}$	$\mathit{0.01}$	$<$ 0.002	Elevated [18, 59, 60]

Those in “bold” are adipokines whose circulating levels have been reported to be elevated in obesity, “italic” those where the circulating levels are lower in obesity, and “normal text” where there is either no effect of obesity or published data. The references are to the reports on circulating levels. The asterisks indicate that the release of these adipokines was almost certainly upregulated over 48 hours. The rate of release for IL-8 over 48 hours extrapolated from release over the first 40 minutes of incubation were 2.2% of those based on the 48 hours release values [61]. The release values for nonfat and fat cells over 48 hours are the averages of subcutaneous and omental adipose tissue from 8 to 12 humans with a BMI of 32 and an equal number with a BMI of 45. These data are from Fain et al., [62] except for haptoglobin [63], resistin [64], MCP-1 [65], TGFβ1 [66], MIF, Cathepsin S, NGF, IL-1Ra, IL-18 [67], VCAM-1, ACE, adipsin, sTNFR2 [68], CD14, LPL, OPG, Amyloid A, ZAG, GPX-3, FABP-4, ICAM-1, RANTES, visfatin, lipocalin-1 [42] while CRP and VEGFR/sFLT1 are from unpublished experiments.