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Introduction Electrical impedance myography (EIM) provides insight into muscle composition and structure. We sought to evaluate its use in a mouse obesity model characterized by myofiber atrophy. Methods We applied a prediction algorithm, i.e., the least absolute shrinkage and selection operator (LASSO), to surface, needle array, and ex vivo EIM data from db/db and WT mice and assessed myofiber cross-sectional area (CSA) histologically and triglyceride (TG) content biochemically. Results EIM data from all three modalities provided acceptable predictions of myofiber CSA with average root mean squared error (RMSE) of 15% in CSA (i.e., ± 209 μm2 for a mean CSA of 1439 μm2 ) and TG content with RMSE of 30% in TG content (i.e., ± 7.3 nmoles TG/mg muscle for a mean TG content of 25.4 nmoles TG/mg muscle). Discussion EIM combined with a predictive algorithm provides reasonable estimates of myofiber CSA and TG content without the need for biopsy.

Significance Ketogenic diet is an effective treatment for nonalcoholic fatty liver disease (NAFLD). Here, we present evidence that hepatic mitochondrial fluxes and redox state are markedly altered during ketogenic diet-induced reversal of NAFLD in humans. Ketogenic diet for 6 d markedly decreased liver fat content and hepatic insulin resistance. These changes were associated with increased net hydrolysis of liver triglycerides and decreased endogenous glucose production and serum insulin concentrations. Partitioning of fatty acids toward ketogenesis increased, which was associated with increased hepatic mitochondrial redox state and decreased hepatic citrate synthase flux. These data demonstrate heretofore undescribed adaptations underlying the reversal of NAFLD by ketogenic diet and highlight hepatic mitochondrial fluxes and redox state as potential treatment targets in NAFLD., Weight loss by ketogenic diet (KD) has gained popularity in management of nonalcoholic fatty liver disease (NAFLD). KD rapidly reverses NAFLD and insulin resistance despite increasing circulating nonesterified fatty acids (NEFA), the main substrate for synthesis of intrahepatic triglycerides (IHTG). To explore the underlying mechanism, we quantified hepatic mitochondrial fluxes and their regulators in humans by using positional isotopomer NMR tracer analysis. Ten overweight/obese subjects received stable isotope infusions of: [D7]glucose, [13C4]β-hydroxybutyrate and [3-13C]lactate before and after a 6-d KD. IHTG was determined by proton magnetic resonance spectroscopy (1H-MRS). The KD diet decreased IHTG by 31% in the face of a 3% decrease in body weight and decreased hepatic insulin resistance (−58%) despite an increase in NEFA concentrations (+35%). These changes were attributed to increased net hydrolysis of IHTG and partitioning of the resulting fatty acids toward ketogenesis (+232%) due to reductions in serum insulin concentrations (−53%) and hepatic citrate synthase flux (−38%), respectively. The former was attributed to decreased hepatic insulin resistance and the latter to increased hepatic mitochondrial redox state (+167%) and decreased plasma leptin (−45%) and triiodothyronine (−21%) concentrations. These data demonstrate heretofore undescribed adaptations underlying the reversal of NAFLD by KD: That is, markedly altered hepatic mitochondrial fluxes and redox state to promote ketogenesis rather than synthesis of IHTG.

Intramyocellular triglyceride (imTG) in skeletal muscle plays a significant role in metabolic health, and an infusion of [(13)C(16)]palmitate can be used to quantitate the in vivo fractional synthesis rate (FSR) and absolute synthesis rate (ASR) of imTGs. However, the extramyocellular TG (emTG) pool, unless precisely excised, contaminates the imTG pool, diluting the imTG-bound tracer enrichment and leading to underestimation of FSR. Because of the difficulty of excising the emTGs precisely, it would be advantageous to be able to calculate the imTG synthesis rate without dissecting the emTGs from each sample. Here, we tested the hypothesis that the ASR of total TGs (tTGs), a combination of imTGs and emTGs, calculated as “FSR × tTG pool,” reasonably represents the imTG synthesis. Muscle lipid parameters were measured in nine healthy women at 90 and 170 min after the start of [(13)C(16)]palmitate infusion. While the measurements of tTG content, enrichment, and FSR did not correlate (P > 0.05), those of the tTG ASR were significantly correlated (r = 0.947, P < 0.05). These results demonstrate that when imTGs and emTGs are pooled, the resulting underestimation of imTG FSR is balanced by the overestimation of the imTG content. We conclude that imTG metabolism is reflected by the measurement of the tTG ASR.

Objectives An assessment of methods for the accurate measurement of low-density lipoprotein cholesterol (LDL-C) at decreased concentrations has not yet been carried out. We evaluated the performance of the Friedewald equation, a direct enzymatic assay, and a novel equation for determining LDL-C levels in a pediatric population with elevated triglycerides and reduced LDL-C levels. Methods LDL-C concentrations of 127 pediatric patients were determined by the Friedewald equation, a direct enzymatic assay, and a novel equation. The bias of each approach was assessed at selected LDL-C cutoffs and after stratifying samples by triglyceride content. The concordance of each approach, relative to the reference method, was determined at LDL-C cut-points of less than 70, 70 to 99, and 100 to 129 mg/dL. Results The Friedewald equation substantially underestimated pediatric LDL-C concentrations below 100 mg/dL in the presence of elevated triglycerides. The Ortho Clinical Diagnostics (Raritan, NJ) direct LDL assay was positively biased at low LDL-C levels. The novel equation most effectively reduced the bias of the Friedewald equation at all LDL-C concentrations and increased the concordance of sample classification to the reference method. Conclusions The novel equation should be used for accurate measurement of pediatric LDL-C when the concentration is below 100 mg/dL in the presence of elevated triglycerides (150-399 mg/dL).

Purpose Epicardial (EAT) and pericardial (PAT) fat masses and myocardial triglyceride content (MTC) are enlarged in obesity and insulin resistance. We studied whether the high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) similarly decrease ectopic fat in and around the heart and whether the decrease is similar in healthy subjects and subjects with defective glucose tolerance (DGT). Methods A total of 28 healthy men (body mass index = 20.7–30.0 kg·m−2, age = 40–55 yr) and 16 men with DGT (body mass index = 23.8–33.5 kg·m−2, age = 43–53 yr) were randomized into HIIT and MICT interventions for 2 wk. EAT and PAT were determined by computed tomography and MTC by 1H-MRS. Results At baseline, DGT subjects had impaired aerobic capacity and insulin sensitivity and higher levels of whole body fat, visceral fat, PAT, and EAT (P < 0.05, all) compared with healthy subjects. In the whole group, HIIT increased aerobic capacity (HIIT = 6%, MICT = 0.3%; time × training P = 0.007) and tended to improve insulin sensitivity (HIIT = 24%, MICT = 8%) as well as reduce MTC (HIIT = −42%, MICT = +23%) (time × training P = 0.06, both) more efficiently compared with MICT, and without differences in the training response between the healthy and the DGT subjects. However, both training modes decreased EAT (−5%) and PAT (−6%) fat (time P < 0.05) and not differently between the healthy and the DGT subjects. Conclusion Whole body fat, visceral fat, PAT, and EAT masses are enlarged in DGT. Both HIIT and MICT effectively reduce EAT and PAT in healthy and DGT subjects, whereas HIIT seems to be superior as regards improving aerobic capacity, whole-body insulin sensitivity, and MTC.

Intoduction Excess visceral and liver fat are known risk factors for cardiometabolic disorders. Metabolomics might allow for easier quantification of these ectopic fat depots, instead of using invasive and costly tools such as MRI or approximations such as waist circumference. Objective We explored the potential use of plasma metabolites as biomarkers of visceral adipose tissue (VAT) and hepatic triglyceride content (HTGC). Methods We performed a cross-sectional analysis of a subset of the Netherlands Epidemiology of Obesity study. Plasma metabolite profiles were determined using the Biocrates AbsoluteIDQ p150 kit in 176 individuals with normal fasting plasma glucose. VAT was assessed with magnetic resonance imaging and HTGC with proton-MR spectroscopy. We used linear regression to investigate the associations of 190 metabolite variables with VAT and HTGC. Results After adjustment for age, sex, total body fat, currently used approximations of visceral and liver fat, and multiple testing, three metabolite ratios were associated with VAT. The strongest association was the lysophosphatidylcholines to total phosphatidylcholines (PCs) ratio [− 14.1 (95% CI − 21.7; − 6.6) cm2 VAT per SD of metabolite concentration]. Four individual metabolites were associated with HTGC, especially the diacyl PCs of which C32:1 was the strongest at a 1.31 (95% CI 1.14; 1.51) fold increased HTGC per SD of metabolite concentration. Conclusion Metabolomics may be a useful tool to identify biomarkers of visceral fat and liver fat content that have added diagnostic value over current approximations. Replication studies are required to validate the diagnostic value of these metabolites.

Drugs facilitating the cardioprotective effects of natriuretic peptides are introduced in heart failure treatment. ANP and BNP also stimulate lipolysis and increase circulating concentrations of free fatty acids (FFAs); an aspect, however, thought to be confined to primates. We examined the lipolytic effect of natriuretic peptide infusion in healthy young men and evaluated the effect in a porcine model of myocardial ischemia and reperfusion.Six young healthy normotensive men underwent infusion with ANP, BNP, or CNP for 20 min. Blood samples were collected before, during, and after infusion for measurement of FFAs. In a porcine model of myocardial ischemia and reperfusion, animals were infused for 3 h with either BNP (n = 7) or saline (n = 5). Blood samples were collected throughout the infusion period, and cardiac tissue was obtained after infusion for lipid analysis.In humans, ANP infusion dose-dependently increased the FFA concentration in plasma 2.5-10-fold (baseline vs. 0.05 mu g/kg/min P Natriuretic peptide infusion has similar lipolytic activity in human and pig. Our data suggest that short-term infusion increases the cardiac lipid content, and that the pig is a suitable model for studies of long-term effects mediated by natriuretic peptides.

Background Previous large population studies reported that non-fasting plasma triglyceride (TG) reflect a higher risk for cardiovascular disease than TG in the fasting plasma. This is suggestive of the presence of higher concentration of remnant lipoproteins (RLP) in postprandial plasma. Methods TG and RLP-TG together with other lipids, lipoproteins and lipoprotein lipase (LPL) in both fasting and postprandial plasma were determined in generally healthy volunteers and in patients with coronary artery disease (CAD) after consuming a fat load or a more typical moderate meal. Results RLP-TG/TG ratio (concentration) and RLP-TG/RLP-C ratio (particle size) were significantly increased in the postprandial plasma of both healthy controls and CAD patients compared with those in fasting plasma. LPL/RLP-TG ratio demonstrated the interaction correlation between RLP concentration and LPL activity The increased RLP-TG after fat consumption contributed to approximately 90% of the increased plasma TG, while approximately 60% after a typical meal. Plasma LPL in postprandial plasma was not significantly altered after either type of meal. Conclusions Concentrations of RLP-TG found in the TG along with its particle size are significantly increased in postprandial plasma compared with fasting plasma. Therefore, non-fasting TG determination better reflects the presence of higher RLP concentrations in plasma.

OBJECTIVE The aim of this study was to determine whether high permittivity (HP) pads can be used to increase the signal-to-noise ratio (SNR) of cardiac proton magnetic resonance spectroscopy at 3 T, allowing faster data acquisition. MATERIALS AND METHODS The institutional review board approved the study protocol, and written informed consent was obtained from all participants. In 22 healthy volunteers, water-suppressed localized spectra were acquired in the interventricular septum without and with HP pads. The SNR and myocardial triglyceride content (MTGC) were measured without and with the HP pads, and the results were compared with a paired sample Student t test. RESULTS Application of HP pads increased mean (SD) SNR from 27.9 (15.6) to 42.3 (24.4) (P < 0.0001), a mean gain of 60%. The acquisition time can thereby be reduced from just under 5 minutes to just under 2 minutes while maintaining the same SNR. The mean (SD) MTGC was 0.39% (0.17%) without pads and 0.38% (0.15%) with pads (P = 0.83) for the healthy volunteers, showing that no bias is introduced by using the pads. No difference in spectral linewidth was measured (P = 0.80), the values being 17.4 (4.9) Hz without and 17.1 (3.2) Hz with pads. Both transmit and receive maps showed increases in sensitivity due to the presence of the HP pads. CONCLUSIONS High permittivity pads improve cardiac proton magnetic resonance spectroscopy at 3 T by increasing the SNR on average by 60%, which can be used to reduce data acquisition time significantly, allowing fast assessment of MTGC without compromising spectral quality. The SNR increase arises primarily from the increase in receive sensitivity of the phased array, which is more closely coupled to the body via the HP pads. In addition, the transmit efficiency is also increased, allowing shorter or lower power radiofrequency pulses.

Ectopic fat is defined by the deposition of triglycerides within cells of non-adipose tissue that normally contain only small amounts of fat. Over the past decade, magnetic resonance spectroscopy has been used extensively for noninvasive quantification of intramyocellular, intrahepatocellular, and more recently myocardial and pancreatic lipids. In liver and muscle, triglyceride content usually correlates with whole-body and tissue-specific insulin sensitivity. However, fat mass and oxidative capacity influence this relationship, indicating that ectopic lipid content is not the only factor that explains insulin resistance. Ectopic lipids may rather serve as biomarkers of the balance between metabolic supply and demand in different states of insulin sensitivity. Consequently, ectopic lipid concentrations, particularly in the liver, decrease with lifestyle- or drug-induced improvement of insulin sensitivity.

Background Because dietary N-3 fatty acids reduce plasma triglycerides, they may also decrease hepatic triglyceride content. If so, N-3 fatty acids might constitute a therapy for fatty liver. Methods Twenty-two subjects were recruited into a study designed to test the effects of N-3 fatty acids on liver fat content. Seventeen completed the trial that had a sequential design of 4-week placebo followed by an 8-week treatment with 9 g/d of fish oil. Liver fat was measured during placebo and treatment by magnetic resonance spectroscopy. Compliance was assessed by capsule count at the end of each study phase and measurement of fatty acid composition in plasma triglyceride and phospholipid. Plasma lipoproteins and adiponectin were also measured. Results Treatment with fish oils reduced significantly levels of plasma triglyceride by 46% ( P Conclusions N-3 fatty acids at high doses lower plasma triglyceride levels, but there are no significant decreases in hepatic content of triglyceride for the group as a whole. Whereas the triglyceride lowering is uniform, the liver response is more variable.

To study the effect of fast-food-based hyper-alimentation on liver enzymes and hepatic triglyceride content (HTGC).Prospective interventional study with parallel control group.University Hospital of Linköping, Sweden.12 healthy men and six healthy women with a mean (SD) age of 26 (6.6) years and a matched control group.Subjects in the intervention group aimed for a body weight increase of 5-15% by eating at least two fast-food-based meals a day with the goal to double the regular caloric intake in combination with adoption of a sedentary lifestyle for 4 weeks.Weekly changes of serum aminotransferases and HTGC measured by proton nuclear magnetic resonance spectroscopy at baseline and after the intervention.Subjects in the intervention group increased from 67.6 (9.1) kg to 74.0 (11) kg in weight (p0.001). Serum ALT increased from 22.1 (11.4) U/l at study start to an individual mean maximum level of 97 (103) U/l (range 19.4-447 U/l). Eleven of the 18 subjects persistently showed ALT above reference limits (women19 U/l, men30 U/l) during the intervention. Sugar (mono- and disaccharides) intake during week 3 correlated with the maximal ALT/baseline ALT ratio (r = 0.62, p = 0.006). HTGC increased from 1.1 (1.9)% to 2.8 (4.8)%, although this was not related to the increase in ALT levels. ALT levels were unchanged in controls.Hyper-alimentation per se can induce profound ALT elevations in less than 4 weeks. Our study clearly shows that in the evaluation of subjects with elevated ALT the medical history should include not only questions about alcohol intake but also explore whether recent excessive food intake has occurred.

Purpose of review To discuss the technique and clinical applications of myocardial and hepatic H magnetic resonance spectroscopy to study myocardial and hepatic triglyceride content, in relation to changes in plasma nonesterified fatty acids induced by nutritional interventions. Recent findings Progressive caloric restriction induces a dose-dependent increase in myocardial triglyceride content and a dose-dependent decrease in diastolic function in lean healthy men. Hepatic triglyceride content shows a differential response to progressive caloric restriction, indicating that redistribution of endogenous triglyceride stores is tissue specific, at least in lean healthy men. A short-term high-fat high-energy diet in healthy men results in major increases in hepatic fat content, whereas it does not influence myocardial triglyceride content or myocardial function. Apparently, there is a differential, tissue-specific partitioning of either triglyceride or fatty acids or both between nonadipose organs such as the human heart and liver during different physiological conditions. Summary Metabolic MRI of myocardial and hepatic triglyceride content is a promising new tool to study the effects of nutritional interventions on myocardial and hepatic lipid metabolism in relation to heart function. Future studies should aim to apply these magnetic resonance techniques to obesity and type 2 diabetes mellitus.

Chylothorax is an unusual type of pleural effusion which results from the accumulation of chyle in the pleural cavity. High triglyceride content and presence of chylomicrons in the chyle give this fluid a characteristic milky appearance. Chylothorax most commonly results from the obstruction of the thoracic duct by a malignant lesion or from its traumatic disruption. Liver cirrhosis is an uncommon and frequently underappreciated cause of chylothorax. Pleural effusion in chylothorax is typically described as a lymphocytic predominant, exudative type and it is exceedingly rare to encounter a transudative type of chylothorax. To date, very few cases of transudative chylothoraces have been described in the literature, most commonly in association with liver cirrhosis. Only a limited range of other clinical settings have been linked to transudative chylothorax and timely recognition of these associations can prevent unnecessary, expensive and sometimes invasive workup in this patient population.

The influence of the aqueous crude extract of Glycine tomentella root (Leguminosae) on lipid metabolism was investigated in hyperlipidemic hamsters. It was found that the administration of the G. tomentella extract (GTE) leads to a decrease of high serum cholesterol and triglyceride levels induced by high-fat diet. The GTE also increased serum high-density lipoprotein (HDL) cholesterol and decreased serum low-density lipoprotein (LDL) cholesterol. The reduction of serum triglyceride levels was accompanied by a significant decrease in the hepatic triglyceride content, while the cholesterol content was not changed. The results indicate that GTE is definitely an anti-hyperlipidemic agent, at least, in animals.

Background: Premature babies have improved clinical outcomes when fed breast milk with a relatively high protein content. Since there was no convenient way of measuring the macronutrition of breast milk we used our routine laboratory pyrogallol red dye binding method for cerebrospinal fluid microprotein (MTP) and our routine method for serum triglyceride to determine the total protein and triglyceride content of human breast milk. Methods: The total protein contents of whole and defatted breast milk samples, randomly collected from 115 nursing mothers, analysed using a pyrogallol red dye binding assay on a Synchron CX7 Delta analyser were compared with the total protein contents determined by dry combustion analysis. Triglyceride concentrations, determined on the Synchron CX7 Delta analyser were compared with their respective creamatocrits. Results: Passing and Bablok regression analysis (95% confidence interval) gave the following regression equations: y = 5.98(5.48 to 6.56)x-1.32(-2.02 to -0.73) where y is whole milk MTP (g/L) and x is dry combustion analysis (g/100 g); y = 7.09 (6.54 to 7.78)x-2.44 (-3.46 to -1.67) where y is volume-corrected defatted milk MTP (g/L) and x is dry combustion analysis (g/100 g); y = 7.52 (6.86 to 8.24)x+0.90(-2.42 to 3.37) where y is whole milk triglyceride (mmol/L) and x is creamatocrit (%). Conclusion: The Synchron CX7 Delta total protein and triglyceride assays provide practical, rapid and reliable methods for the determination of the macronutrition in human milk.

Hepatic lipid content was assessed noninvasively in 15 patients with hepatic steatosis by 13C nuclear magnetic resonance (NMR) spectroscopy, and compared in a double-blind fashion with histological grading and morphometric quantitation of fat in liver biopsies taken within 2 weeks of the study. The lipid content in the liver biopsies was expressed as the volume fraction of total parenchyma occupied by fat. Hepatic triglyceride content was determined by comparing the 13C NMR signal intensity in vivo with the signal intensity obtained from a lipid phantom of known concentrations. There was an approximately 30-fold increase in the 13C NMR signals of the saturated carbons (methyl/methylene [CH2]n) region of hepatic triglycerides from patients with grade 4 steatosis compared with those with grade 0, yielding a good dynamic range for measuring hepatic triglyceride content. The correlation coefficient between the morphometric and 13C NMR techniques was 0.89 (P < .01). These studies demonstrate that 13C NMR spectroscopy can be used to noninvasively assess hepatic triglyceride content in humans. This method may be clinically useful for diagnosis and follow-up of patients with hepatic steatosis.

To prospectively compare an investigational version of a complex-based chemical shift-based fat fraction magnetic resonance (MR) imaging method with MR spectroscopy for the quantification of hepatic steatosis.This study was approved by the institutional review board and was HIPAA compliant. Written informed consent was obtained before all studies. Fifty-five patients (31 women, 24 men; age range, 24-71 years) were prospectively imaged at 1.5 T with quantitative MR imaging and single-voxel MR spectroscopy, each within a single breath hold. The effects of T2 correction, spectral modeling of fat, and magnitude fitting for eddy current correction on fat quantification with MR imaging were investigated by reconstructing fat fraction images from the same source data with different combinations of error correction. Single-voxel T2-corrected MR spectroscopy was used to measure fat fraction and served as the reference standard. All MR spectroscopy data were postprocessed at a separate institution by an MR physicist who was blinded to MR imaging results. Fat fractions measured with MR imaging and MR spectroscopy were compared statistically to determine the correlation (r(2)), and the slope and intercept as measures of agreement between MR imaging and MR spectroscopy fat fraction measurements, to determine whether MR imaging can help quantify fat, and examine the importance of T2 correction, spectral modeling of fat, and eddy current correction. Two-sided t tests (significance level, P = .05) were used to determine whether estimated slopes and intercepts were significantly different from 1.0 and 0.0, respectively. Sensitivity and specificity for the classification of clinically significant steatosis were evaluated.Overall, there was excellent correlation between MR imaging and MR spectroscopy for all reconstruction combinations. However, agreement was only achieved when T2 correction, spectral modeling of fat, and magnitude fitting for eddy current correction were used (r(2) = 0.99; slope ± standard deviation = 1.00 ± 0.01, P = .77; intercept ± standard deviation = 0.2% ± 0.1, P = .19).T1-independent chemical shift-based water-fat separation MR imaging methods can accurately quantify fat over the entire liver, by using MR spectroscopy as the reference standard, when T2 correction, spectral modeling of fat, and eddy current correction methods are used.

This review evaluates recent research findings and proposes an up-to-date diagnostic approach for patients with suspected chylothorax.Typically, chylothorax is a milky exudate with high triglyceride content (110 mg/dl). However, milky appearance is not always the case and triglyceride levels can be less than 110 mg/dl, especially in fasting or malnourished patients. Transudative chylothoraces have been reported when cirrhosis, nephrosis or heart failure co-exist. In addition, although the vast majority of the white blood cells in chyle are lymphocytes, chylothoraces can be neutrophilic, especially the postsurgical ones.Chylothorax is the accumulation of chyle into the pleural cavity usually due to thoracic duct leak and should be suspected not only in patients with milky effusions but also in the presence of certain co-morbidities or history of chest/neck trauma. Fluid triglycerides more than 110 mg/dl or less than 50 mg/dl virtually establish or exclude the diagnosis, respectively; ambiguous cases with values 50-110 mg/dl require lipoprotein analysis for the demonstration of chylomicrons. In fasting or malnourished patients lipoprotein analysis is suggested even with triglycerides less than 50 mg/dl. Typical pleural fluid in chylothorax is a lymphocytic exudate with low lactate dehydrogenase; atypical fluid characteristics (i.e. transudative nature, neutrophil-predominance or high lactate dehydrogenase) may be a sign of additional causes of pleural fluid accumulation.

Aim: To investigate the reproducibility of measurements of hepatic triglyceride content (HTGC) in subjects with normal HTGC using localized 1H-magnetic resonance spectroscopy (1H-MRS) and a clinical 1.5T scanner. Methods: The 1H-MRS acquisition was performed with a common protocol using the whole-body coil and no respiratory triggering. An upper limit of normal HTGC of 5.56% was used. Duplicate measurements, including subject repositioning, were acquired from 23 subjects, 19 of whom had a normal HTGC. Results: The mean coefficient of variation (CV) from the duplicate measurements was 14.8% (20.5% before exclusion of a subject who was considered to be an outlier). Mean CVs of subgroups below and above the 1% HTGC limit were 19.8 and 7.0 respectively. Conclusions: The mean CV calculated in subjects with HTGC in the normal range was found to be higher than CVs of wide range HTGC groups reported in the literature. It is concluded that the reproducibility of HTGC measurements using 1H-MRS depends on the HTGC range. These findings are of importance in reproducibility studies and in estimations of required study group sizes.

Background Targets for cholesterol reduction are part of the Quality Outcomes Framework and general practitioners have to meet these targets to fulfil their remuneration package. By contrast, there are no targets for the accuracy of cholesterol or other lipid measurements and no recent surveys on performance of these assays. We have assessed the performance of lipid measurement of the available methods in the UK. Methods Serum samples collected from individual donors attending the national blood service were distributed after values were obtained from a secondary reference laboratory. Samples were sent to participant laboratories to assess different methods' analytical performance on single donation specimens, on routine external quality assessment pooled specimens, on specimens subjected to a range of freeze–thaw cycles and on frozen-stored specimens. Results Differences in measured cholesterol were found that were method-dependent and related to triglyceride content. HDL-cholesterol (HDL-C) showed significant positive bias in all assays. Individual donor specimens showed no significant changes with differing numbers of freeze–thaw cycles. Pooled serum was stable for up to six months. Conclusions Most cholesterol measurements are accurate but some methods are affected by triglyceride interference. HDL-C methods show significant positive bias. Although there are potential matrix effects introduced as a result of specimen preparation, additional work is needed to show if these effects are present in fresh patient samples.

The liver phospholipid and triglyceride content and/or fatty acid pattern differ(s) not solely in normal versus diabetic rats, but also in distinct rat models of diabetes mellitus. The present study reveals that a comparable situation prevails in the brain. Fed and overnight fasted female normal rats (N) and Goto-Kakizaki rats (GK), as well as fed rats rendered diabetic by a prior injection 3 days before sacrifice of streptozotocin (STZ) were examined. The brain phospholipid content, expressed as milligrams of fatty acids per gram wet weight, was comparable in all groups of rats, with an overall mean value of 31.2+/-0.8 (n=22). The GK rats differed from N and STZ rats by lower C18:0/C18:1omega9 and C18:2omega6/C18:3omega6 ratios and a lower C20:5omega3 content of brain phospholipids. The total amount of fatty acids in triglycerides was 7-8 times higher in GK than N and STZ rats. The GK rats differed from N and STZ rats by lower C16:0/C16:1omega7, C18:0/C18:1omega9 and (C16:0+C16:1omega7)/(C18:0+C18:1omega9) ratios in triglycerides. These findings extend to the brain, the knowledge of alterations in phospholipid and triglyceride content and/or fatty acid pattern in GK rats, as compared to N or STZ rats. The former rats indeed displayed: (i) an apparently increased activity of Delta9- and Delta6-desaturases, as suggested by the phospholipid measurements, and a decreased C20:5omega3 content in such phospholipids; (ii) a dramatic increase in brain triglyceride content; and (iii) an increased activity of Delta9-desaturase, as well as elongase, as judged from the triglyceride data.

Despite the increasing prevalence of nonalcoholic fatty liver disease (NAFLD), the criteria used to diagnose the disorder remain poorly defined. Localized proton magnetic resonance spectroscopy (MRS) accurately measures hepatic triglyceride content (HTGC) but has been used only in small research studies. Here, MRS was used to analyze the distribution of HTGC in 2,349 participants from the Dallas Heart Study (DHS). The reproducibility of the procedure was validated by showing that duplicate HTGC measurements were high correlated ( r = 0.99, P < 0.001) and that the coefficient of variation between measurements was low (8.5%). Intake of a high-fat meal did not significantly affect the measurements, and values were similar when measurements were made from the right and left hepatic lobes. To determine the “upper limit of normal” for HTGC, the distribution of HTGC was examined in the 345 subjects from the DHS who had no identifiable risk factors for hepatic steatosis (nonobese, nondiabetic subjects with minimal alcohol consumption, normal liver function tests, and no known liver disease). The 95th percentile of HTGC in these subjects was 5.56%, which corresponds to a hepatic triglyceride level of 55.6 mg/g. With this value as a cutoff, the prevalence of hepatic steatosis in Dallas County was estimated to be 33.6%. Thus MRS provides a sensitive, quantitative, noninvasive method to measure HTGC and, when applied to a large urban US population, revealed a strikingly high prevalence of hepatic steatosis.

Intramyocellular triglycerides (imcTG) of skeletal muscle are an important energy source for muscle work in mammals. However, the metabolism and regulation of this small intracellular neutral lipid pool are largely unknown. This is in part due to the difficulties involved with its sampling and measurement introduced by contaminants of extramyocellular triglycerides (emcTG). The contents of imcTG reported to date for both human and rodent muscle are of unusually high variability not only across species, but also within same individuals and even same muscle groups. Recent studies suggested that the inherent muscle histologic heterogeneity does not appear to be a major source for the high variability as previously believed. Rather, the new experimental data showed that the procedures commonly used to process muscle specimens before lipid extraction appear inadequate to ensure a complete removal of emcTG contaminants. The extramyocellular lipid contaminants cause an overestimation of imcTG content and markedly increase its variability. Careful and meticulous microdissection has been found necessary in order to avoid contamination by emcTG, thereby obtaining pure muscle fibers for extraction of imcTG.

To determine the extent and microanatomical distri- bution of extramyocellular adipocytes associated with skeletal muscle, histological, biochemical, nuclear magnetic resonance proton spectroscopic and microcomputed tomography tech- niques were employed to analyze skeletal muscle samples from lean and obese Sprague-Dawley rats. Significant amounts of extramyocellular adipocytes were found on the exterior surface of rat gastrocnemius, soleus, and tibialis anterior muscles. The triglyceride content of these exterior adipocytes in these muscle groups was 2- to 3-fold greater than that of the respec- tive intramyocellular triglyceride pool ( P � 0.01). Thus, the exterior adipocytes associated with skeletal muscle samples are an abundant source of extramyocellular fat potentially contam- inating the intramyocellular triglyceride pool if not carefully and completely removed. On the other hand, no adipocytes were found in the interfascicular space (between muscle bundles) or the intrafascicular space (between muscle fibers) in any of the three rat muscles. The feasibility of and procedures for re- moving extramyocellular fat by microdissection techniques to obtain pure muscle sample were also evaluated. Complete removal of the extramyocellular adipocytes from rat skeletal muscle, using microdissection with a stereo microscope, was found to be practical and effective. It is concluded that pure muscle samples free of contamination by extramyocellular fat can be obtained, but only if microdissection techniques are utilized. — Guo, Z., P. Mishra, and S. Macura. Sampling the intramyocellular triglycerides from skeletal muscle. J. Lipid Res. 2001. 42: 1041-1048.

Glucose is usually chosen as the energy source for total parenteral nutrition. However, the optimal glucose : fat ratio for peripheral parenteral nutrition has not been examined sufficiently. We compared glucose : fat ratios in hypocaloric nutrition. Male SD rats were given hypocaloric parenteral nutrition (approx. 190 kcal/kg/d) for 5 d after laparotomy. The hypocaloric solutions used contained 0, 33, 50, 67 or 100% of the non-protein energy in the form of fat. Body weight change, nitrogen balance, organ weights, and hepatic, splenic and plasma biochemistries were assessed. Body weight increase in the 67 and 100% fat groups was significantly greater than that in the 0 % fat group. Nitrogen balance was the same in all groups. Hepatic glycogen content was significantly lower in the 100% fat group than that in the 0 % fat group. The weight of epididymal fat deposits was significantly lower in the 0 % fat group than in the 50 and 67% fat groups. On the other hand, tissue triglyceride content and plasma lipid levels in the 100% fat group were significantly higher than in the 0 % fat group, and were also higher than in the control group. It is suggested that combinations of glucose and fat have sparing effects on body fat and hepatic glycogen. Combinations of glucose and fat as non-protein energy sources were superior to glucose or fat alone for hypocaloric parenteral nutrition.

Purpose: Effect of recombinant human growth hormone (rhGH) administration on lipid storage, and its subsequent effect on insulin sensitivity have not yet been adequately examined. Thus, we investigated the effects of rhGH treatment on muscle triglyceride (TG) and ceramide content, and insulin sensitivity after 4 weeks of rhGH administration in rats. Materials and Methods: Fourteen rats were randomly assigned to two groups: rhGH injection group (GH, n = 7) and saline injection group (CON, n = 7). GH received rhGH by subcutaneous injections (130 g·kg μ -1 ·day -1 , 6 days·week -1 ) for 4 weeks, while CON received saline injections that were equivalent in volume to GH group. Intramuscular TG and ceramide content and hepatic TG content were measured. To determine insulin sesitivity, oral glucose tolerance test (OGTT) and muscle incubation for glucose transport rate were performed in rats, and used as indicators of insulin sensitivity. We also examined plasm lipid profiles. Results: After 4 weeks of rhGH treatment, the GH group had higher muscle and liver TG contents than the CON (p < 0.05). Ceramide content in GH was significantly greater than that in CON (p < 0.05). GH also had higher plasma levels of FFA (p < 0.05), glucose and insulin responses during OGTT (p < 0.05), and lower glucose transport rates in submaximal insulin concentration (p < 0.05) as compared with CON. Results indicate that rhGH treatment is associated with insulin resistance in rats. Conclusion: rhGH treatment elevated muscle TG and ceramide content, and hepatic TG content. Thus, elevation of these compounde by rhGH treatment could contribute to the development of insulin resistance in rats.

The production rate and composition of cerumen have been studied in 11 participants (5 men and 6 women), 25 to 42 years old. The cerumen was obtained in January, May, July, and November to investigate the possible influence of the season. Only the triglyceride content decreased from November to July. Sex was not a factor, which supported the hypothesis that sex hormones play a minor role in the production rate of the lipid component of cerumen.

The galactose elimination capacity (GEC) of rats fed low protein liquid diets and libitum with 5% or 0.5% of the energy as protein was compared with that of a control group receiving a similar diet with 25% of the energy as protein. The daily dietary energy intake was almost identical in the three groups. The rats fed the 5% protein diet showed slightly higher GEC than the control group. In the rats receiving the 0.5% protein diet, GEC was significantly decreased to approximately half of the control values and the hepatic protein content was reduced to the same extent. Body weight and liver weight showed reductions to approximately 75% of control values. Triglyceride content in the livers was increased five times in the protein depleted rats. The results indicate that GEC in rats deprived of dietary protein is determined by the amount of hepatic protein.

Studies of pure human low density lipoproteins (LDL) in the analytical ultracentrifuge revealed three groups of normolipidemic individuals of which 19 41 (46%) had heterogeneous LDL. The most common finding in individuals with heterogeneous LDL, 16 19 individuals, was the presence of a major fast LDL component, group Fs. The three other individuals with heterogeneous LDL had a major slow LDL component, group fS. Fifty-four percent of individuals ( 22 41 ) had homogeneous LDL, group S, in which the S f ,1.2,KBr of 39.8 closely agreed with the major LDL component of the fS group, S f = 40.7. In group Fs, the major LDL component was S f of 45.5 and was highly correlated with low serum triglyceride content, mean triglycerides concentration of 48 vs 91 mg/dl in group fS and S. Neither age nor sex appeared to be related to the occurrence of heterogeneous LDL, except as it is correlated with serum triglyceride values.

Summary o (1) Analysis of the sera of more than 100 wild baboons, Papio ursinus , revealed that the cholesteryl esters had the following fatty acid composition: 22.7 palmitic, 5.8 palmitoleic, 10.4 stearic, 24.8 oleic, 31.7 linoleic, 1.0 linolenic, and 5.0% arachidonic acids. The total unsaturated cholesteryl fatty acids comprised 68.4% of the total cholesteryl esters. (2) The average fatty acid composition of the phospholipids was as follows: 29.1 palmitic, 3.1 palmitoleic, 21.5 stearic, 16.9 oleic, 20.0 linoleic, 1.1 linolenic and 7.2 arachidonic acids. The total phospholipid contained 48.3% unsaturated acids. (3) The fatty acid composition of the triglycerides was the following, i.e. 34.7 palmitic, 7.5 palmitoleic, 11.2 stearic, 32.0 oleic, 14.3 linoleic, 1.3 linolenic and 2.5% arachidonic acids. (4) Very low density lipoproteins of baboon sera contained a higher proportion of the saturated fatty acids in cholesteryl esters, phospholipids and triglycerides than the high density lipoproteins. (5) In baboon sera the high density lipoprotein fractions contained about 55%, 59% and 80% of the total cholesterol, fatty acids, and phospholipids, respectively. Of the total triglyceride content of baboon sera, about 64% was found in the very low density fraction.

Effects of sympathetic denervation on biochemical and morphological changes of brown adipose tissue (BAT) were studied in rats after severing 5 intercostal nerve bundles that enter the unilateral interscapular BAT, the contralateral BAT being used as the control. Four weeks after denervation, there was no appreciable change in BAT weight or its DNA and protein contents, whereas the triglyceride content was increased significantly. However, the rate of fatty acid synthesis was decreased to about half the rate in controls. The denervated BAT was much paler than controls and contained lots of adipocytes filled with large lipid droplets, some of which were unilocular. The results are discussed with reference to changes in BAT seen after bilateral lesions of the ventromedial hypothalamus.

Male rats given 6-chloro-6-deoxyglucose (240 mg/kg/day for 28 days) developed spermatocoeles in their ductuli efferentes or caput epididymides. They had a lower serum triglyceride content than controls (0.87 +/- 0.19 vs 1.84 +/- 0.19 mM, Mean +/- SEM; n = 6) and gained less weight (2.55 +/- 0.37 vs 4.1 +/- 0.96 g/day, Mean +/- SEM; n = 6). There was no effect on female rats which received the same treatment. Spermatocoeles could also be produced by a single dose of 6-chloro-6-deoxyglucose, the threshold dose was between 180 and 240 mg/kg. Glucose oxidation by liver, brain, kidney and diaphragm from rats given 6-chloro-6-deoxyglucose (240 mg/kg/day for 14 days) was the same as in controls but was decreased in seminiferous tubules (0.32 +/- 0.06 vs 0.74 +/- 0.02 mumol [U-14C]glucose oxidised to 14CO2/g fresh wt/h, Mean +/- SEM; n = 3). The activity of glyceraldehyde-3-phosphate dehydrogenase [E.C. 1.2.1.12] in liver, brain, testis or muscle from rats given 6-chloro-6-deoxyglucose (24 mg/kg/day for 14 days) showed little change although its activity in spermatozoa was dramatically decreased.

Summary: The effect of the maternal environment on umbilical cord plasma lipid concentrations was studied in a group of mothers and babies. Changes in neonatal plasma concentrations during the first week of life were followed in a small group of infants. The lipoprotein distribution of the cholesterol and triglyceride content of umbilical cord plasma was similar to that seen in maternal plasma at delivery. Neonatal plasma cholesterol was significantly correlated with the cholesterol content of maternal low density lipoprotein. Neonatal plasma triglyceride concentration was related to maternal parity, duration of labour and the existence of maternal hypertension and to the occurrence of foetal distress and dysmaturity.

In two groups of obese diabetic patients closely matched for age, glucose intolerance and indices of obesity, the group with hypertriglyceridaemia was found to have an increased triglyceride content of adipocytes (p less than 0.001) and raised fasting plasma insulin (p less than 0.02). Plasma insulin did not directly relate to the level of plasma triglyceride (r = +0.28, n = 36, p N.S.) but correlated with the triglyceride content of adipocytes (r = +0.59, n = 37, p less than 0.001). The results suggest that raised plasma insulin is not a primary determinant of the level of plasmatriglyceride but that it may be related by its effect on lipogenesis in adipose and other tissues.

Young male rats were fed with diets containing Hungarian soya products (extruded or granulated soya preparates) as the only source of protein for four weeks. The weight gain of the animals, the cholesterol and triglyceride content of liver and the activity of the hepatic monooxygenase system were studied. 20% soya protein in the diet (either from extruded or from granulated soya products) supplemented with sulphur containing amino acids met the protein requirement of the young growing rats. In a separate experiment the protein depletion-repletion method was used to investigate the effect of Purina 500 E soya protein isolate on the above mentioned parameters. The results indicate that diets containing 20% soya protein are satisfactory for the regeneration of the protein depleted animals.

These was a significant decrease in the blood and the biliary triglyceride levels of the rats with acute carbon tetrachloride toxicity. This was accompanied by a 4-fold increase in the hepatic triglyceride content. These results have been discussed in terms of a direct toxic effect of carbon tetrachloride on the hepatic triglyceride secretory mechanisms. A marked reduction in the biliary content of triglyceride will facilitate the accumulation of triglyceride in the liver and will contribute significantly toward the genesis of fatty liver in CCI4-toxic rats.

The lipomobilizing power of the aorta was investigated in animals of various ages (3, 6, 12, 18 and 24 months old). Lipomobilization was followed up in vivo after the intraperitoneal injection of adrenalin, by means of FFA values in the aorta. An in vivo experiment after the intraperitoneal injection of adrenalin was carried out in animals adapted to the chronic administration of ACTH-Corticot rophin Spofa. The FFA release from the aorta of old animals was found to be decreased. A decreased FFA response in the aorta was observed in animals adapted to repeated ACTH administration, In in vivo experiments after incubation with adrenalin less FFA were liberated into the medium from the aorta of ageing and old animals. The age of the animal also influenced the total aortic triglyceride content in relation to its nitrogen content it increased with age.

A study of the influence of adrenocorticotropin (ACTH) on various adrenal lipid fractions of intact rats indicated that single and repeated doses (3 or 10 days administration) of ACTH had a lipolytic effect on adrenal fat. A decrease of cholesterol and triglyceride content of the adrenal gland after a single dose of ACTH was observed. However, after 3 days injection of ACTH, only the cholesterol concentration diminished. The triglyceride content was the same as that in saline-injected control animals. On the other hand, a significant increase in triglycerides was noted in adrenal gland after 10 days of ACTH injections. No substantial changes in unesterified fatty acids and phospholipids were noted in response to a single dose, or to repeated doses of ACTH.

1. 1. The effect of the nerve growth factor on the lipids of 8-day-old chickembryo sensory ganglia has been studied. Total lipids increased, and the ganglionic dry weight remained almost unchanged. 2. 2. Separation of neutral lipids showed that a rise in triglyceride content was accompanied by an increase in esterified and total cholesterol, whereas free fatty acids and a sterol-like compound diminished. 3. 3. Total phospholipids were only slightly affected, but sphingomyelin decreased significantly. A certain tendency towards lyso compounds was observed. 4. 4. The mode of action of the nerve growth factor in the light of the presented results has been discussed as an effect on enzymes concerned with neutral lipid synthesis.

A screening procedure, based on the determination of total lipids and total cholesterol and on electrophoresis of lipoproteins on cellulose acetate is described to distinguish sera with normal or elevated triglyceride content. When classification rules for typing hyperlipaemias, proposed in the literature and established from data obtained from sera with a high total lipid content, were applied to a patient population with normal or moderately elevated total serum lipids, an improbably high incidence of Type III was found. New classification rules for typing such patients are presented, leading to a far more acceptable incidence of Type III.

Total body water (TBW), lean body mass (LBM), and triglyceride mass were measured in 23 5-yr-old baboons (13 females and 10 males). Male baboons weighed more, had more LBM, more TBW, and contained less triglyceride mass per unit body weight than female baboons. Among all baboons, triglyceride mass per unit body weight ranged from 2.4 to 33.5%. The ratio TBW:LBM ranged from 0.70 to 0.92, increasing (r = 0.98) with increased body triglyceride content (both percent and absolute mass) in both male and female baboons. However, the water content per unit weight of tissues free of fat cells (liver, lungs, kidneys, central nervous system, eyes, tongue) was nearly constant at 0.73 +/- 0.02. The increase in TBW:LBM is more than can be expected from the water in the increased adipose tissue mass. We conclude that TBW:LBM is not constant but is influenced by body triglyceride content in baboons.

The effect of ethanol (1, 2 and 4 mg/g i.v.) on hepatic triglyceride content, hepatic lipid release and plasma esterified fatty acid levels was investigated in mice. Within 4–8 hr all doses of ethanol increased the triglyceride content of the liver to about the same degree. Lipid secretion from the liver was inhibited 2 hr after the administration of 4 mg/g ethanol and increased 8 hr after the injection of 2 and 4 mg/g ethanol. Plasma esterified fatty acids showed an initial increase after 1 mg/g and an initial decrease after 4 mg/g ethanol. Eight hr after the administration of 4 mg/g ethanol the level of esterified fatty acids in the plasma was increased. Two mg/g ethanol did not have any effect on plasma esterified fatty acid levels. From the absence of a clear correlation of the three parameters tested it is concluded that inhibition of lipid secretion from the liver is not a major reason for the development of acute alcoholic fatty liver in mice.

1. Serum and lipoprotein cholesterol and triglycerides were measured before, during and after the administration of glutethimide (500 mg daily) for 21 days to six healthy volunteer subjects. 2. Evidence of enzyme induction was provided by significant rises in d-glucaric acid excretion and antipyrine clearance. 3. Concentrations of total serum cholesterol, very-low-density-lipoprotein-, low-density-lipoprotein-and high-density-lipoprotein-cholesterol rose significantly during treatment. 4. The time course of these changes was delayed in comparison with the rise and fall in d-glucaric acid excretion. 5. There was no change in the triglyceride content of either whole serum or lipoprotein fractions at any time during the trial. 6. The study provides further evidence that enzyme-inducing agents cause a rise in certain lipid concentrations.

The effect of exposure to cold (+2 degrees C, 3 and 24 h) and fasting (1, 2 and 3 days) on placental glycogen and triglyceride content was investigated in rats pregnant for 20 days. The stimuli did not affect the level of glycogen in the placenta. The level of triglycerides remained unchanged in the rats exposed to cold. It rose after only one day of fasting and then levelled out on the 2nd and 3rd days. Fasting, but not exposure to cold produced hypoglycemia and elevation of the plasma free fatty acids level. We conclude that activation of the adrenergic system during exposure to cold does not interfere with the glycogen and triglyceride content of the placenta. Prolonged hypoglycemia also does not affect the placental glycogen level although it increases the accumulation of neutral fat.

Lingual lipase (LL) activity, pH, and products of fat hydrolysis were determined in gastric aspirates from preterm infants who received formula milk feeds by a nasogastric tube. In 1-hourly (n = 9), 2-hourly (n = 8) and 3-hourly (n = 9) fed infants LL activity increased to reach its maximum value at 60, 90, and 120 min respectively after the feeds, and gastric pH levels fell from about 6.0 to less than 3.5. There was a reduction in triglyceride content to 50% of the initial value, measured immediately after a feed, and the products of hydrolysis were mainly diglycerides and FFA. In a subsequent study 3-hourly fed infants (n = 8) had a tube feed followed by a bottle feed, and then a bottle feed followed by a tube feed on successive days (cross-over). The LL activity observed after a bottle feed (mean maximal value 23.8 mumol FFA/ml/h) was significantly higher than after a tube feed (19.1 mumol FFA/ml/h). It is suggested that substantial triglyceride hydrolysis takes place in the stomach due to lingual lipase, and sucking seems to enhance enzyme production.