Comparison of Lipid and Fatty Acid Composition of the Liver, Subcutaneous and Intra‐abdominal Adipose Tissue, and Serum

Abstract

Ceramides may mediate saturated fat–induced insulin resistance, but there are no data comparing ceramide concentrations between human tissues. We therefore performed lipidomic analysis of human subcutaneous (SCfat) and intra‐abdominal (IAfat) adipose tissue, the liver, and serum in eight subjects. The liver contained (nmol/mg tissue) significantly more ceramides (1.5–3‐fold), sphingomyelins (7–8‐fold), phosphatidylethanolamines (10–11‐fold), lysophosphatidylcholines (7–12‐fold), less ether‐linked phosphatidylcholines (2–2.5‐fold) but similar amounts of diacylglycerols as compared to SCfat and IAfat. The amounts of ceramides and their synthetic precursors, such as palmitic (16:0) free fatty acids and sphingomyelins, differed considerably between the tissues. The liver contained proportionally more palmitic, stearic (18:0), and long polyunsaturated fatty acids than adipose tissues. Stearoyl‐CoA desaturase 1 (SCD1) activity reflected by serum, estimated from the 16:1/16:0‐ratio, was closely related to that in the liver (r = 0.86, P = 0.024) but not adipose tissues. This was also true for estimated elongase (18:1/16:1, r = 0.89, P = 0.01), and Δ5 (20:4/20:3, r = 0.89, P = 0.012) and Δ6 (18:3[n‐6]/18:2, r = 1.0, P < 0.001) desaturase activities. We conclude that the human liver contains higher concentrations of ceramides and saturated free fatty acids than either SCfat or IAfat.

Gender-Dependent Associations of Metabolite Profiles and Body Fat Distribution in a Healthy Population with Central Obesity: Towards Metabolomics Diagnostics

“…Therefore, the relative high level of LCAT in obese subjects may be responsible for clearance of specific PC species. In addition, relative high levels of PCs in adipose tissues compared to other tissues may explain the relation of PCs to BFD (Kotronen et al, 2010).…”

“…PC 32:0 was included in the model of VAT, whereas PC-O 36:5 and PC O-34:2 were included in the model of A:G ratio, possibly indicating tissue and fatty acid specific enzyme activity (Pynn et al, 2011;Raclot et al, 2001). For example, enzymes converting esterified fatty acids are known to vary between tissues (Kotronen et al, 2010). PC 32:0 is a new potential indicator of VAT size and abdominal obesity, as PC 32:0 has been shown earlier to be related to obesity (Oberbach et al, 2011).…”

In vivo hepatic lipid quantification using MRS at 7 Tesla in a mouse model of glycogen storage disease type 1a

“…To date, a liver biopsy is necessary to analyze the fatty acid composition, commonly performed by gas chromatography (GC), a technique requiring the extraction and preparation of tissue samples ( 12 ). However, a liver biopsy is an invasive and painful technique that can lead to false negative results ( 13 ), and is not suitable for longitudinal studies .…”

Plasma fatty acids as predictors of glycaemia and type 2 diabetes

“…PL and CE fatty acid compositions reflect the dietary intake of fatty acids during the preceding weeks [1,[7][8][9][10][11]. The TG fatty acid composition represents dietary intake from only the few preceding days and provides an opportunity to evaluate hepatic enzyme activities [1,12,13]. Evidence for an association between different types of fatty acid and the risk of type 2 diabetes mellitus is inconsistent, with the exception of key enzymes in the metabolism of polyunsaturated fatty acids (PUFAs), Δ 5 -desaturase (D5D) and Δ 6 -desaturase (D6D), which have been consistently associated with incident diabetes [14].…”