Technical Note: In vivo estimation of lipogenesis using a bolus injection of [U- 13C]glucose in pigs

2021 ◽  
Author(s):  
H H Salgado ◽  
A Remus ◽  
C Pomar ◽  
M P Létourneau-Montminy ◽  
H Lapierre
Keyword(s):  
Adipose Tissue ◽  
Bolus Injection ◽  
De Novo ◽  
Technical Note ◽  
Radioactive Isotopes ◽  
De Novo Lipogenesis ◽  
Finishing Pigs ◽  
Commercial Diet ◽  
Tissue Lipids

Abstract The use of radioactive isotopes to measure de novo lipogenesis in pigs has been well established. Different from radioactive isotopes, stable isotopes present little or no risk to human and animal subjects. Therefore, the objective of this study was to adapt the method of bolus injection of radioactive glucose ( 14C) to use 13C-labelled glucose to estimate de novo lipogenesis in finishing pigs. Five vein-catheterized gilts received 3.0 kg/day of a commercial diet for 2 wk. The last day, the pigs received a bolus injection of [U- 13C]glucose (12 mg/kg BW). A serial of blood samples was taken for 4 h to determine glucose rate of disappearance (Rd) from plasma glucose isotopic enrichment (IE). The 13C IE of lipids was determined from adipose tissue biopsies collected at 1, 2 and 3 h after the bolus injection, and from adipose tissue collected after pig euthanasia 4 h after the bolus. Lipogenesis was estimated from the incorporation of 13C from glucose into adipose tissue lipids. Glucose Rd, estimated using a double exponential function, averaged 5.4 ± 1.4 mmol/min. The IE of lipids increased linearly during the 4 h following the bolus injection (P < 0.05). The rate of incorporation of glucose into lipids, estimating lipogenesis, averaged 9.0 µg glucose/(min × g of lipids) 4 h after the bolus injection. In conclusion, the in vivo method using a bolus injection of [U- 13C]glucose allows a successful estimation of de novo lipogenesis in finishing pigs.

scholarly journals Adipose Tissue—Breast Cancer Crosstalk Leads to Increased Tumor Lipogenesis Associated with Enhanced Tumor Growth

2021 ◽  
Vol 22 (21) ◽  
pp. 11881
Author(s):  
Peter Micallef ◽  
Yanling Wu ◽  
Marco Bauzá-Thorbrügge ◽  
Belén Chanclón ◽  
Milica Vujičić ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Adipose Tissue ◽  
Tumor Growth ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Continuous Treatment ◽  
Accelerated Growth ◽  
Opposing Effects

We sought to identify therapeutic targets for breast cancer by investigating the metabolic symbiosis between breast cancer and adipose tissue. To this end, we compared orthotopic E0771 breast cancer tumors that were in direct contact with adipose tissue with ectopic E0771 tumors in mice. Orthotopic tumors grew faster and displayed increased de novo lipogenesis compared to ectopic tumors. Adipocytes release large amounts of lactate, and we found that both lactate pretreatment and adipose tissue co-culture augmented de novo lipogenesis in E0771 cells. Continuous treatment with the selective FASN inhibitor Fasnall dose-dependently decreased the E0771 viability in vitro. However, daily Fasnall injections were effective only in 50% of the tumors, while the other 50% displayed accelerated growth. These opposing effects of Fasnall in vivo was recapitulated in vitro; intermittent Fasnall treatment increased the E0771 viability at lower concentrations and suppressed the viability at higher concentrations. In conclusion, our data suggest that adipose tissue enhances tumor growth by stimulating lipogenesis. However, targeting lipogenesis alone can be deleterious. To circumvent the tumor’s ability to adapt to treatment, we therefore believe that it is necessary to apply an aggressive treatment, preferably targeting several metabolic pathways simultaneously, together with conventional therapy.

scholarly journals Anti-Obesity Effects of Microalgae

2019 ◽  
Vol 21 (1) ◽  
pp. 41 ◽  
Author(s):  
Saioa Gómez-Zorita ◽  
Jenifer Trepiana ◽  
Maitane González-Arceo ◽  
Leixuri Aguirre ◽  
Iñaki Milton-Laskibar ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
In Vivo Studies ◽  
Acid Oxidation ◽  
Low Grade ◽  
Food Ingredients ◽  
Brown Adipose

In recent years, microalgae have attracted great interest for their potential applications in nutraceutical and pharmaceutical industry as an interesting source of bioactive medicinal products and food ingredients with anti-oxidant, anti-inflammatory, anti-cancer, and anti-microbial properties. One potential application for bioactive microalgae compounds is obesity treatment. This review gathers together in vitro and in vivo studies which address the anti-obesity effects of microalgae extracts. The scientific literature supplies evidence supporting an anti-obesity effect of several microalgae: Euglena gracilis, Phaeodactylum tricornutum, Spirulina maxima, Spirulina platensis, or Nitzschia laevis. Regarding the mechanisms of action, microalgae can inhibit pre-adipocyte differentiation and reduce de novo lipogenesis and triglyceride (TG) assembly, thus limiting TG accumulation. Increased lipolysis and fatty acid oxidation can also be observed. Finally, microalgae can induce increased energy expenditure via thermogenesis activation in brown adipose tissue, and browning in white adipose tissue. Along with the reduction in body fat accumulation, other hallmarks of individuals with obesity, such as enhanced plasma lipid levels, insulin resistance, diabetes, or systemic low-grade inflammation are also improved by microalgae treatment. Not only the anti-obesity effect of microalgae but also the improvement of several comorbidities, previously observed in preclinical studies, has been confirmed in clinical trials.

Adipose tissue triglyceride turnover, de novo lipogenesis, and cell proliferation in humans measured with 2H2O

2004 ◽  
Vol 286 (4) ◽  
pp. E577-E588 ◽  
Author(s):  
A. Strawford ◽  
F. Antelo ◽  
M. Christiansen ◽  
M. K. Hellerstein
Keyword(s):  
Cell Proliferation ◽  
Adipose Tissue ◽  
Half Life ◽  
De Novo ◽  
Human Subjects ◽  
De Novo Lipogenesis ◽  
Gas Chromatography Mass Spectrometry ◽  
Distribution Analysis ◽  
Mass Isotopomer Distribution Analysis

The turnover of adipose tissue components (lipids and cells) and the pathways of adipose lipid deposition have been difficult to measure in humans. We apply here a 2H2O long-term labeling technique for concurrent measurement of adipose-triglyceride (TG) turnover, cell (DNA) proliferation, and de novo lipogenesis (DNL). Healthy subjects drank 2H2O (70 ml/day) for 5-9 wk. Subcutaneous adipose tissue aspirates were taken (gluteal, thigh, and flank depots). Deuterium incorporation into TG glycerol (representing all-source TG synthesis), TG palmitate (representing DNL, by mass isotopomer distribution analysis), and DNA (representing cell proliferation) was measured by gas chromatography-mass spectrometry. Subjects tolerated the protocol well, and body 2H2O enrichments were stable. Mean TG-glycerol fractional synthesis was 0.12 (i.e., 12%) with a range of 0.03-0.32 after 5 wk and 0.20 (range 0.08-0.49) after 9 wk (TG half-life 200-270 days). Label decay measurements 5-8 mo after discontinuing 2H2O gave similar turnover estimates. Net lipolysis (TG turnover) was 50-60 g/day. DNL contribution to adipose-TG was 0.04 after 9 wk, representing ∼20% of newly deposited TG. Cell proliferation was 0.10-0.17 after 9 wk (half-life 240-425 days). In summary, long-term 2H2O administration to human subjects allows measurement of the dynamics of adipose tissue components. Turnover of all elements is slow, and DNL contributes ∼20% of new TG.

Effect of carbohydrate intake on de novo lipogenesis in human adipose tissue

1987 ◽  
Vol 253 (6) ◽  
pp. E664-E669 ◽  
Author(s):  
C. Chascione ◽  
D. H. Elwyn ◽  
M. Davila ◽  
K. M. Gil ◽  
J. Askanazi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Whole Body ◽  
High Intake ◽  
Carbohydrate Diet ◽  
Triglyceride Synthesis ◽  
High Carbohydrate

Rates of synthesis, from [14C]glucose, of fatty acids (de novo lipogenesis) and glycerol (triglyceride synthesis) were measured in biopsies of adipose tissue from nutritionally depleted patients given low- or high-carbohydrate intravenous nutrition. Simultaneously, energy expenditure and whole-body lipogenesis were measured by indirect calorimetry. Rates of whole-body lipogenesis were zero on the low-carbohydrate diet and averaged 1.6 g.kg-1.day-1 on the high-carbohydrate diet. In vitro rates of triglyceride synthesis increased 3-fold going from the low to the high intake; rates of fatty acid synthesis increased approximately 80-fold. In vitro, lipogenesis accounted for less than 0.1% of triglyceride synthesis on the low intake and 4% on the high intake. On the high-carbohydrate intake, in vitro rates of triglyceride synthesis accounted for 61% of the rates of unidirectional triglyceride synthesis measured by indirect calorimetry. In vitro rates of lipogenesis accounted for 7% of whole-body lipogenesis. Discrepancies between in vitro rates of fatty acid synthesis from glucose, compared with acetate and citrate, as reported by others, suggest that in depleted patients on hypercaloric high-carbohydrate diets, adipose tissue may account for up to 40% of whole-body lipogenesis.

scholarly journals Metabolic Effects of Oral Phenelzine Treatment on High-Sucrose-Drinking Mice

2018 ◽  
Vol 19 (10) ◽  
pp. 2904 ◽  
Author(s):  
Christian Carpéné ◽  
Saioa Gómez-Zorita ◽  
Alice Chaplin ◽  
Josep Mercader
Keyword(s):  
Adipose Tissue ◽  
Phosphoenolpyruvate Carboxykinase ◽  
De Novo ◽  
Uncoupling Protein ◽  
De Novo Lipogenesis ◽  
Metabolic Effects ◽  
Mrna Levels ◽  
Brown Adipose ◽  
High Sucrose ◽  
Sucrose Drinking

Phenelzine has been suggested to have an antiobesity effect by inhibiting de novo lipogenesis, which led us to investigate the metabolic effects of oral chronic phenelzine treatment in high-sucrose-drinking mice. Sucrose-drinking mice presented higher body weight gain and adiposity versus controls. Phenelzine addition did not decrease such parameters, even though fat pad lipid content and weights were not different from controls. In visceral adipocytes, phenelzine did not impair insulin-stimulated de novo lipogenesis and had no effect on lipolysis. However, phenelzine reduced the mRNA levels of glucose transporters 1 and 4 and phosphoenolpyruvate carboxykinase in inguinal white adipose tissue (iWAT), and altered circulating levels of free fatty acids (FFA) and glycerol. Interestingly, glycemia was restored in phenelzine-treated mice, which also had higher insulinaemia. Phenelzine-treated mice presented higher rectal temperature, which was associated to reduced mRNA levels of uncoupling protein 1 in brown adipose tissue. Furthermore, unlike sucrose-drinking mice, hepatic malondialdehyde levels were not altered. In conclusion, although de novo lipogenesis was not inhibited by phenelzine, the data suggest that the ability to re-esterify FFA is impaired in iWAT. Moreover, the effects on glucose homeostasis and oxidative stress suggest that phenelzine could alleviate obesity-related alterations and deserves further investigation in obesity models.

scholarly journals Targeting de novo lipogenesis and the Lands cycle induces ferroptosis in KRAS-mutant lung cancer

2021 ◽  
Author(s):  
Caterina Bartolacci ◽  
Cristina Andreani ◽  
Goncalo Dias do Vale ◽  
Stefano Berto ◽  
Margherita Melegari ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Fatty Acid ◽  
Metabolic Networks ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Genetically Engineered ◽  
De Novo Lipogenesis ◽  
Main Process

Mutant KRAS (KM) is the most common oncogene in lung cancer (LC). KM regulates several metabolic networks, but their role in tumorigenesis is still not sufficiently characterized to be exploited in cancer therapy. To identify metabolic networks specifically deregulated in KMLC, we characterized the lipidome of genetically engineered LC mice, cell lines, patient derived xenografts and primary human samples. We also determined that KMLC, but not EGFR-mutant (EGFR-MUT) LC, is enriched in triacylglycerides (TAG) and phosphatidylcholines (PC). We also found that KM upregulates fatty acid synthase (FASN), a rate-limiting enzyme in fatty acid (FA) synthesis promoting the synthesis of palmitate and PC. We determined that FASN is specifically required for the viability of KMLC, but not of LC harboring EGFR-MUT or wild type KRAS. Functional experiments revealed that FASN inhibition leads to ferroptosis, a reactive oxygen species (ROS)-and iron-dependent cell death. Consistently, lipidomic analysis demonstrated that FASN inhibition in KMLC leads to accumulation of PC with polyunsaturated FA (PUFA) chains, which are the substrate of ferroptosis. Integrating lipidomic, transcriptome and functional analyses, we demonstrated that FASN provides saturated (SFA) and monounsaturated FA (MUFA) that feed the Lands cycle, the main process remodeling oxidized phospholipids (PL), such as PC. Accordingly, either inhibition of FASN or suppression of the Lands cycle enzymes PLA2 and LPCAT3, promotes the intracellular accumulation of lipid peroxides and ferroptosis in KMLC both in vitro and in vivo. Our work supports a model whereby the high oxidative stress caused by KM dictates a dependency on newly synthesized FA to repair oxidated phospholipids, establishing a targetable vulnerability. These results connect KM oncogenic signaling, FASN induction and ferroptosis, indicating that FASN inhibitors already in clinical trial in KMLC patients (NCT03808558) may be rapidly deployed as therapy for KMLC.

scholarly journals AMPK Activation Reduces Hepatic Lipid Content by Increasing Fat Oxidation In Vivo

2018 ◽  
Vol 19 (9) ◽  
pp. 2826 ◽  
Author(s):  
Marc Foretz ◽  
Patrick Even ◽  
Benoit Viollet
Keyword(s):  
Lipid Metabolism ◽  
De Novo ◽  
Fat Oxidation ◽  
De Novo Lipogenesis ◽  
Acid Oxidation ◽  
Ampk Activation ◽  
Hepatic Lipid ◽  
Adenoviral Delivery ◽  
Body Production

The energy sensor AMP-activated protein kinase (AMPK) is a key player in the control of energy metabolism. AMPK regulates hepatic lipid metabolism through the phosphorylation of its well-recognized downstream target acetyl CoA carboxylase (ACC). Although AMPK activation is proposed to lower hepatic triglyceride (TG) content via the inhibition of ACC to cause inhibition of de novo lipogenesis and stimulation of fatty acid oxidation (FAO), its contribution to the inhibition of FAO in vivo has been recently questioned. We generated a mouse model of AMPK activation specifically in the liver, achieved by expression of a constitutively active AMPK using adenoviral delivery. Indirect calorimetry studies revealed that liver-specific AMPK activation is sufficient to induce a reduction in the respiratory exchange ratio and an increase in FAO rates in vivo. This led to a more rapid metabolic switch from carbohydrate to lipid oxidation during the transition from fed to fasting. Finally, mice with chronic AMPK activation in the liver display high fat oxidation capacity evidenced by increased [C14]-palmitate oxidation and ketone body production leading to reduced hepatic TG content and body adiposity. Our findings suggest a role for hepatic AMPK in the remodeling of lipid metabolism between the liver and adipose tissue.

scholarly journals A Role for Adipose Tissue De Novo Lipogenesis in Glucose Homeostasis During Catch-up Growth: A Randle Cycle Favoring Fat Storage

Diabetes ◽  
2012 ◽  
Vol 62 (2) ◽  
pp. 362-372 ◽  
Author(s):  
H. Marcelino ◽  
C. Veyrat-Durebex ◽  
S. Summermatter ◽  
D. Sarafian ◽  
J. Miles-Chan ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Homeostasis ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Fat Storage ◽  
Catch Up

scholarly journals Beneficial Effects of Bariatric Surgery-Induced by Weight Loss on the Proteome of Abdominal Subcutaneous Adipose Tissue

2020 ◽  
Vol 9 (1) ◽  
pp. 213
Author(s):  
Bárbara María Varela-Rodríguez ◽  
Paula Juiz-Valiña ◽  
Luis Varela ◽  
Elena Outeiriño-Blanco ◽  
Susana Belén Bravo ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Positive Impact ◽  
De Novo Lipogenesis ◽  
Beneficial Effects ◽  
Proteomic Approach ◽  
Subcutaneous Adipose

Bariatric surgery (BS) is the most effective treatment for obesity and has a positive impact on cardiometabolic risk and in the remission of type 2 diabetes. Following BS, the majority of fat mass is lost from the subcutaneous adipose tissue depot (SAT). However, the changes in this depot and functions and as well as its relative contribution to the beneficial effects of this surgery are still controversial. With the aim of studying altered proteins and molecular pathways in abdominal SAT (aSAT) after body weight normalization induced by BS, we carried out a proteomic approach sequential window acquisition of all theoretical mass spectra (SWATH-MS) analysis. These results were complemented by Western blot, electron microscopy and RT-qPCR. With all of the working tools mentioned, we confirmed that after BS, up-regulated proteins were associated with metabolism, the citric acid cycle and respiratory electron transport, triglyceride catabolism and metabolism, formation of ATP, pyruvate metabolism, glycolysis/gluconeogenesis and thermogenesis among others. In contrast, proteins with decreased values are part of the biological pathways related to the immune system. We also confirmed that obesity caused a significant decrease in mitochondrial density and coverage, which was corrected by BS. Together, these findings reveal specific molecular mechanisms, genes and proteins that improve adipose tissue function after BS characterized by lower inflammation, increased glucose uptake, higher insulin sensitivity, higher de novo lipogenesis, increased mitochondrial function and decreased adipocyte size.

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