1H-NMR Spectroscopic Studies of Lipid Extracts from Human Fatty Liver

doi:10.1006/bbrc.1993.1546

Biochemical and Biophysical Research Communications

Volume 192, Issue 3, 14 May 1993, Pages 1217-1222

https://doi.org/10.1006/bbrc.1993.1546 Get rights and content

Abstract

Lipid extracts of biopsy samples from normal and non-alcohol-induced fatty human liver were studied by ¹H-NMR at 200 MHz. Spectra of the lipid extracts from 10 mg samples were obtained in 6 min with routine acquisition parameters and allowed the calculation of the phosphatidyicholine to total fatty acyl chain ratio, the cholesterol to total fatty acyl chain ratio, the average fatty acyl chain length, the unsaturation ratio and the acylated glycerol to total fatty acyl chain ratio. The data suggest that lipids with a higher ratio of de novo synthesized fatty acyl chains are stored in non-alcohol-induced fatty liver. NMR lipid analysis appears to be a reliable method for the rapid assessment of hepatic lipid composition on bioptic specimens.

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Cited by (23)

The neuropeptide TLQP-21 opposes obesity via C3aR1-mediated enhancement of adrenergic-induced lipolysis
2017, Molecular Metabolism
Citation Excerpt :
1H 90° pulse width and transmitter offset were optimized for each sample. All spectra were zero-filled to 128 k data points, Fourier transformed with 1 Hz line broadening applied, manually phased, baseline corrected, and integrated using Topspin software [24,25]. Statistical analyses were performed with Statistica 12.0 (Dell Inc.), and significance was set at p < 0.05.
Obesity is characterized by excessive fat mass and is associated with serious diseases such as type 2 diabetes. Targeting excess fat mass by sustained lipolysis has been a major challenge for anti-obesity therapies due to unwanted side effects. TLQP-21, a neuropeptide encoded by the pro-peptide VGF (non-acronymic), that binds the complement 3a receptor 1 (C3aR1) on the adipocyte membrane, is emerging as a novel modulator of adipocyte functions and a potential target for obesity-associated diseases. The molecular mechanism is still largely uncharacterized.
We used a combination of pharmacological and genetic gain and loss of function approaches. 3T3-L1 and mature murine adipocytes were used for in vitro experiments. Chronic in vivo experiments were conducted on diet-induced obese wild type, β₁, β₂, β₃-adrenergic receptor (AR) deficient and C3aR1 knockout mice. Acute in vivo lipolysis experiments were conducted on Sprague Dawley rats.
We demonstrated that TLQP-21 does not possess lipolytic properties per se. Rather, it enhances β-AR activation-induced lipolysis by a mechanism requiring Ca²⁺ mobilization and ERK activation of Hormone Sensitive Lipase (HSL). TLQP-21 acutely potentiated isoproterenol-induced lipolysis in vivo. Finally, chronic peripheral TLQP-21 treatment decreases body weight and fat mass in diet induced obese mice by a mechanism involving β-adrenergic and C3a receptor activation without associated adverse metabolic effects.
In conclusion, our data identify an alternative pathway modulating lipolysis that could be targeted to diminish fat mass in obesity without the side effects typically observed when using potent pro-lipolytic molecules.
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The purpose of the present study was (i) to establish a modality for non-invasively probing bile composition in cynomolgus monkeys and (ii) to ascertain the variability in biliary metabolism by repeatedly assessing gallbladder bile in situ. Localised in vivo ¹H magnetic resonance spectroscopy (MRS) provided high-resolution spectra of gallbladder bile that allowed for the first time different species of bile acids, their taurine and glycine conjugates, and phospholipids to be identified and quantified in situ. A combined cross-sectional and longitudinal study of bile composition was conducted over 4 weeks in monkeys kept under standardised nutritional conditions. All biles were composed of the same major constituents. Bile acids contributed 267 ± 47 μmol/ml whereof cholate, deoxycholate and chenodeoxycholate were the most abundant primary bile acids. Bile acid conjugation reached an extent of 100%. However, the actual quantitative contributions of different bile constituents varied distinctly. Correlation analysis revealed that intra-individual variability (r = 0.77 ± 0.03) was significantly (p < 0.01) smaller than inter-individual variability (r = 0.68 ± 0.01), thus purporting the notion that bile composition is a hallmark of individual metabolism. Extension of quantitative bile analysis by in vivo ¹H-MRS to pathological states will provide a rapid and non-invasive modality for monitoring an important, yet elusive compartment of cholesterol and lipid metabolism.
Increase in the concentration of carbon 18 monounsaturated fatty acids in the liver with hepatitis C: Analysis in transgenic mice and humans
2001, Biochemical and Biophysical Research Communications
Steatosis is one of the histologic characteristics of chronic hepatitis C and is well reproduced in a transgenic mouse model for hepatocellular carcinoma (HCC) in which the core protein of hepatitis C virus (HCV) plays a pivotal role in inducing steatosis and HCC. In the present study, the lipid composition in the liver of the HCV core gene transgenic mice as well as in those of chronic hepatitis C patients was determined. The concentration of carbon 18 monounsaturated (C18:1) fatty acids, such as oleic and vaccenic acids, which are known to increase membrane fluidity leading to higher cell division rates, significantly increased in the livers of transgenic mice compared to nontransgenic control mice. The concentration of C18:1 fatty acids also significantly increased in the livers of chronic hepatitis C patients compared to subjects without HCV infection. These results suggest that HCV may affect a specific pathway in the lipid metabolism and cause steatosis in the liver.
NMR study of lipid changes in organs of jirds infected with Echinococcus multilocularis
1999, Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Proton NMR spectroscopy was used to investigate changes in composition of lipids in the liver, kidneys and adrenal glands of Meriones unguiculatus infected with Echinococcus multilocularis. It was found that all three organs of infected animals had less total glycerophospholipid and CH₂ in the fatty acid (FA) component CHCH(CH₂CHCH)_n than the corresponding organs of uninfected animals. The concentrations of other lipids in these organs were variable in their response to infection. The livers of infected jirds had lower concentrations of phosphatidylcholine (PTC), phosphatidylinositol, cholesterol (CTL) and the FA component CH₂CH₂COO, but more phosphatidylethanolamine (PTE). Kidneys of infected animals had less PTC, PTE and arachidonic acid. The adrenal glands, which were most affected by E. multilocularis infection, had lower concentrations of PTE, CTL, total FA, triacylglycerol, linoleic acid, and the FA components CH₂CH₂COO, CH₂COO, CH₂ in (CH₂)_n, CHCH and CH₂CHCH.
Alterations in membrane fatty acid unsaturation and chain length in hypertension as observed by <inf>1</inf>H NMR spectroscopy
1998, American Journal of Hypertension
Alterations in fatty acids of membrane phospholipids in essential hypertension may account for altered membrane ion transport, elasticity, and contractility properties of hypertensive tissues. To investigate the abnormalities in membrane fatty acids in essential hypertension, the degree of fatty acid unsaturation ([–CHCH–]/[–CH₃]), the average carbon chain length, ratio of glycerol to fatty acyl chains, ratio of phosphatidylcholine to fatty acyl chains, and the ratio of free and acylated cholesterol to fatty acyl chains in fatty acid fractions of membrane phospholipids of aorta, kidney, and heart were determined in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats by ¹H nuclear magnetic resonance (NMR) spectroscopy. The degrees of fatty acid unsaturation in the aorta and the kidney membranes were significantly lower in SHR than in WKY rats (aorta, 0.53 ± 0.01 v 0.63 ± 0.01, n = 5, P = .01; kidney, 0.70 ± 0.01 v 0.84 ± 0.03, n = 10, P = .01). No significant difference could be detected in fatty acid unsaturation in heart membranes between these two strains. For aorta, kidney, and heart membranes, the average carbon chain lengths of fatty acid fractions of membrane phospholipids were significantly shorter for SHR than for WKY rats (aorta, 15.1 ± 0.2 v 18.3 ± 0.7, n = 5, P = .02; kidney, 14.5 ± 0.2 v 16.4 ± 0.4, n = 10, P = .01; heart, 17.3 ± 0.5 v 18.8 ± 0.6, n = 10, P = .05). The lower unsaturated fatty acid content in membrane phospholipids of the aorta and the kidney, with concomitant reduction in average chain length, may arise from increased oxidation of fatty acid double bonds in hypertensive tissues and may account, in part, for the increased aortic stiffness and abnormal kidney function associated with essential hypertension. Whether the lower unsaturated fatty acid content and decreased carbon chain length of phospholipid membranes in the aorta and the kidney are a cause or a consequence of the high blood pressure, however, remains unknown.
Analysis of total lipid extracts from human liver by 13C and 1H nuclear magnetic resonance spectroscopy
1996, Analytical Biochemistry
Lipid extracts of liver tissue from normal donors and from patients with acute liver failure were analyzed by¹³C NMR and¹H NMR at 9.4 T. The spectra allowed estimation of (i) the free fatty acid to total fatty acid chains ratio, (ii) the polyunsaturated to monounsaturated lipids ratio, (iii) the glycerophospholipids to triacylglycerols ratio, (iv) the total cholesterol to total fatty acids molar ratio, (v) the acylcholesterol to cholesterol ratio, (vi) the phosphatidylcholine to phosphatidylethanolamine molar ratio, and (vii) the unsaturation ratio of the fatty acid chains. The values obtained for normal livers agree with literature data on lipid composition obtained by other techniques. The two pathologic livers differ from the normal in the composition of some lipids and show a higher free fatty acid to total fatty acid chains ratio and a lower polyunsaturated to monounsaturated lipid ratio, a lower acylcholesterol to cholesterol ratio, and a lower phosphatidylcholine to phosphatidylethanolamine ratio, whereas the ratio of total cholesterol to fatty acids and the unsaturation ratio remained unchanged. The detailed assignment of the¹³C NMR spectra of lipid extracts from normal and pathologic human liver may contribute to direct future research programs on¹³C NMR spatially localized spectroscopy of the liverin vivo.

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Biochemical and Biophysical Research Communications

Abstract

References (0)

Cited by (23)

The neuropeptide TLQP-21 opposes obesity via C3aR1-mediated enhancement of adrenergic-induced lipolysis

Non-invasive analysis of gallbladder bile composition in cynomolgus monkeys using in vivo <sup>1</sup>H magnetic resonance spectroscopy

Increase in the concentration of carbon 18 monounsaturated fatty acids in the liver with hepatitis C: Analysis in transgenic mice and humans

NMR study of lipid changes in organs of jirds infected with Echinococcus multilocularis

Alterations in membrane fatty acid unsaturation and chain length in hypertension as observed by <inf>1</inf>H NMR spectroscopy

Analysis of total lipid extracts from human liver by <sup>13</sup>C and <sup>1</sup>H nuclear magnetic resonance spectroscopy

Regular Article1H-NMR Spectroscopic Studies of Lipid Extracts from Human Fatty Liver

Abstract

Regular Article
¹H-NMR Spectroscopic Studies of Lipid Extracts from Human Fatty Liver