The fatty acid pattern of adipose tissue and liver triglycerides according to fat droplet size in liver parenchymal cells of diabetic subjects

Сингер, Петер; Gnauck, G; Honigmann, G; Stolz, Peter; Schliack, V; Kettler, L. H.; Buntrock, P; Thoelke, H

doi:10.1007/bf01221637

Cited by 10 publications

(5 citation statements)

References 28 publications

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“…The fatty acid distribution in the triglyceride fractions differed significantly from that in the fatty acid fractions. The predominance of unsaturated fatty acids in the triglycerides is consistent with earlier observations (14)(15)(16)(17). In contrast, saturated fatty acids predominated in the free fatty acid fractions.…”

Section: Discussionsupporting

confidence: 92%

“…Laurel1 and Lundquist found up to 1.7% pentadecanoic acid in hepatic triglycerides and no heptadecanoic acid (14). Neither Kessler et al (15), Takahashi and Tanaka (16), or Singer et al (17) reported any odd chain fatty acids in the liver. Any presence of pentadecanoic acid in the free fatty acid fraction would have resulted in an underestimation of the free fatty acid concentration in our study.…”

Section: Lipid Analysismentioning

confidence: 93%

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Hepatic Free Fatty Acids in Alcoholic Liver Disease and Morbid Obesity

et al. 2007

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Alcoholic liver disease is characterized by the accumulation of fat and inflammatory changes in the liver. Because free fatty acids, the precursors of triglycerides, can damage biological membranes, accumulation of free fatty acids in the liver might be in part responsible for the functional and morphological changes seen in alcoholic liver disease. We, therefore, determined the hepatic lipid composition in biopsies from 31 patients with alcoholic liver disease, 18 patients with morbid obesity, and 5 patients without evidence of liver disease. Free fatty acids were found in all liver biopsies. Patients with morbid obesity or alcoholic liver disease had significantly higher fatty acid and triglyceride levels than did controls (p <, 0.01). Patients with alcoholic liver disease had significantly higher fatty acid levels than did patients with morbid obesity (p < 0.05), while there was no difference in the triglyceride concentrations between these two groups. The distribution of the fatty acids in the free fatty acid fraction differed significantly from that in the triglyceride fraction indicating a preferential incorporation of unsaturated fatty acids into triglycerides. This difference in the distribution pattern was lost in patients with the most severe forms of alcoholic liver disease. The data are consistent with the hypothesis that accumulation of free fatty acids in patients with alcoholic liver disease may be responsible for or contribute to the observed functional and morphological damages.

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Section: Discussionsupporting

confidence: 92%

Section: Lipid Analysismentioning

confidence: 93%

Hepatic Free Fatty Acids in Alcoholic Liver Disease and Morbid Obesity

et al. 2007

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“…Stepping through discrete values for ndb 1 shows that ndb 1 should be in the range ± 1 in order for ndb to remain in a valid range; it is not possible to determine a precise value for ndb 1 from the data in this study. A propensity for a negative value is supported by Singer et al and Mavrelis et al, which indicate that liver fat is more saturated at higher PDFF levels and, on this basis, the present study hypothesizes a value at the low end of the valid range of ndb 1 = −1.…”

Section: Resultssupporting

confidence: 78%

“…In addition to optimizing for the average ndb, there may be compositional changes in the fat compartment that cause ndb to systematically vary with PDFF. Changes in free fatty acid concentration and triglyceride composition with fat content have been reported in chemical analyses of biopsy samples, and there have been suggestive findings in MRS of correlation (both positive and negative) between ndb and the volume of fat in various depots, although not specifically in liver . In order to accommodate a systematic variation of this type, ndb was modeled as a constant plus linear term in PDFF:

ndb = {ndb}_{0} + {ndb}_{1} \cdot PDFF

…”

Section: Methodsmentioning

confidence: 99%

Sources of systematic error in proton density fat fraction (PDFF) quantification in the liver evaluated from magnitude images with different numbers of echoes

et al. 2017

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DK088925The purpose of this work was to investigate sources of bias in magnetic resonance imaging (MRI) liver fat quantification that lead to a dependence of the proton density fat fraction (PDFF) on the number of echoes. This was a retrospective analysis of liver MRI data from 463 subjects. The magnitude signal variation with TE from spoiled gradient echo images was curve fitted to estimate the PDFF using a model that included monoexponential R 2 * decay and a multi-peak fat spectrum.Additional corrections for non-exponential decay (Gaussian), bi-exponential decay, degree of fat saturation, water frequency shift and noise bias were introduced. The fitting error was minimized with respect to 463 × 3 = 1389 subject-specific parameters and seven additional parameters associated with these corrections. The effect on PDFF was analyzed, notably the dependence on the number of echoes. The effects on R 2 * were also analyzed. The results showed that the inclusion of bias corrections resulted in an increase in the quality of fit (r 2 ) in 427 of 463 subjects (i.e. 92.2%) and a reduction in the total fitting error (residual norm) of 43.6%. This was largely a result of the Gaussian decay (57.8% of the reduction), fat spectrum (31.0%) and biexponential decay (8.8%) terms. The inclusion of corrections was also accompanied by a decrease in the dependence of PDFF on the number of echoes. Similar analysis of R 2 * showed a decrease in the dependence on the number of echoes. Comparison of PDFF with spectroscopy indicated excellent agreement before and after correction, but the latter exhibited lower bias on a Bland-Altman plot (1.35% versus 0.41%). In conclusion, correction for known and expected biases in PDFF quantification in liver reduces the fitting error, decreases the dependence on the number of echoes and increases the accuracy. | INTRODUCTIONQuantitative measures of the fat content in liver are increasingly being used as biological markers of non-alcoholic fatty liver disease (NAFLD) and other metabolic disorders. [1][2][3][4] Qualitative evaluation of the fat content using magnetic resonance imaging (MRI) has been routinely used for a long time by assessing the difference between the in-phase (IP) and opposed-phase (OP) images. 5,6 Abbreviations used: FA, flip angle; FOV, field of view; HIPAA, Health Insurance Portability and Accountability Act; IP, in-phase; IRB, Institutional Review Board; MRI, magnetic resonance imaging; MRS, magnetic resonance spectroscopy; NAFLD, non-alcoholic fatty liver disease; ndb, number of double bonds; OP, opposed-phase; PDFF, proton density fat fraction; ROI, region of interest; SNR, signal-to-noise ratio; SPGR, spoiled gradient recalled-echo; STEAM, stimulated echo acquisition mode However, qualitative and semi-quantitative methods are difficult to standardize and can be implementation dependent, which can complicate the use of MRI for the monitoring of patients over time, especially if they are scanned on different scanners or with different techniques. Thus, there are advantages to...

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“…Our results tally with other reports on human hepatic tissue that employed chromatography and other analytical in vitro methods. As far back as 50 years ago, Singer [ 24 ] showed that mono-, di- and polyunsaturated fatty acid content differs between normal and steatotic livers and that polyunsaturated fatty acid (PUFA) content decreases in correlation with increased diameter of fat droplets.…”

Section: Discussionmentioning

confidence: 99%

Lipid Profile and Hepatic Fat Content Measured by 1H MR Spectroscopy in Patients before and after Liver Transplantation

et al. 2021

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Increased hepatic fat content (HFC) is a hallmark of non-alcoholic fatty liver (NAFL) disease, a common condition in liver transplant recipients. Proton MR spectroscopy (1H MRS) and MR imaging-based proton density fat fraction as the only diagnosis modality enable precise non-invasive measurement of HFC and, also, fatty acid profiles in vivo. Using 1H MRS at 3T, we examined 47 liver transplantation candidates and 101 liver graft recipients. A point-resolved spectroscopy sequence was used to calculate the steatosis grade along with the saturated, unsaturated and polyunsaturated fractions of fatty acids in the liver. The steatosis grade measured by MRS was compared with the histological steatosis grade. HFC, represented by fat fraction values, is adept at distinguishing non-alcoholic steatohepatitis (NASH), NAFL and non-steatotic liver transplant patients. Relative hepatic lipid saturation increases while unsaturation decreases in response to increased HFC. Additionally, relative hepatic lipid saturation increases while unsaturation and polyunsaturation both decrease in liver recipients with histologically proven post-transplant NASH or NAFL compared to non-steatotic patients. HFC, measured by in vivo 1H MRS, correlated well with histological results. 1H MRS is a simple and fast method for in vivo analysis of HFC and its composition. It provides non-invasive support for NAFL and NASH diagnoses.

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The fatty acid pattern of adipose tissue and liver triglycerides according to fat droplet size in liver parenchymal cells of diabetic subjects

Cited by 10 publications

References 28 publications

Hepatic Free Fatty Acids in Alcoholic Liver Disease and Morbid Obesity

Hepatic Free Fatty Acids in Alcoholic Liver Disease and Morbid Obesity

Sources of systematic error in proton density fat fraction (PDFF) quantification in the liver evaluated from magnitude images with different numbers of echoes

Lipid Profile and Hepatic Fat Content Measured by 1H MR Spectroscopy in Patients before and after Liver Transplantation

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