Metabolic dysfunction-associated steatotic liver disease (MASLD) occurs in subjects with obesity and metabolic syndrome. MASLD may progress from simple steatosis (i.e., hepatic steatosis) to steatohepatitis, characterized by inflammatory changes and liver cell damage, substantially increasing mortality. Lifestyle measures associated with weight loss and/or appropriate diet help reduce liver fat accumulation, thereby potentially limiting progression to steatohepatitis. As for diet, both total energy and macronutrient composition significantly influence the liver's fat content. For example, the type of dietary fatty acids can affect the metabolism of lipids and hence their tissue accumulation, with saturated fatty acids having a greater ability to promote fat storage in the liver than polyunsaturated ones. In particular, polyunsaturated fatty acids of n-3 series (omega-3), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been intensively studied for their antisteatotic effects, both in preclinical animal models of obesity and hepatic steatosis and in overweight/obese patients. Their effects may depend not only on the dose and duration of administration of omega-3, or DHA/EPA ratio, but also on the lipid class used for their supplementation. This review summarizes the available evidence from recent comparative studies using omega-3 supplementation via different lipid classes. Albeit the evidence is mainly limited to preclinical studies, it suggests that phospholipids and possibly wax esters could provide greater efficacy against MASLD compared to traditional chemical forms of omega-3 supplementation (i.e., triacylglycerols, ethyl esters). This cannot be attributed solely to improved EPA and/or DHA bioavailability, but other mechanisms may be involved. Keywords: MASLD • Metabolic dysfunction-associated steatotic liver disease • NAFLD • Non-alcoholic fatty liver disease • n-3 polyunsaturated fatty acids.

• MeSH
• játra * metabolismus   účinky léků   patologie   MeSH
• lidé MeSH
• metabolismus lipidů účinky léků   MeSH
• nealkoholová steatóza jater metabolismus   farmakoterapie   dietoterapie   patologie   MeSH
• obezita metabolismus   farmakoterapie   dietoterapie   patologie   MeSH
• omega-3 mastné kyseliny * aplikace a dávkování   metabolismus   terapeutické užití   MeSH
• potravní doplňky * MeSH
• ztučnělá játra metabolismus   farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• omega-3 mastné kyseliny * MeSH

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) can progress to more severe stages, such as steatohepatitis and fibrosis. Thermoneutral housing together with high-fat diet promoted NAFLD progression in C57BL/6J mice. Due to possible differences in steatohepatitis development between different C57BL/6 substrains, we examined how thermoneutrality affects NAFLD progression in C57BL/6N mice. METHODS: Male mice were fed standard or high-fat diet for 24 weeks and housed under standard (22°C) or thermoneutral (30°C) conditions. RESULTS: High-fat feeding promoted weight gain and hepatic steatosis, but the effect of thermoneutral environment was not evident. Liver expression of inflammatory markers was increased, with a modest and inconsistent effect of thermoneutral housing; however, histological scores of inflammation and fibrosis were generally low (<1.0), regardless of ambient temperature. In standard diet-fed mice, thermoneutrality increased weight gain, adiposity, and hepatic steatosis, accompanied by elevated de novo lipogenesis and changes in liver metabolome characterized by complex decreases in phospholipids and metabolites involved in urea cycle and oxidative stress defense. CONCLUSION: Thermoneutrality appears to promote NAFLD-associated phenotypes depending on the C57BL/6 substrain and/or the amount of dietary fat.

• Klíčová slova
• C57BL/6N mice, NASH, de novo lipogenesis, liver steatosis, metabolomics, non-alcoholic fatty liver disease, obesity, thermoneutrality,
• MeSH
• bydlení MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• hmotnostní přírůstek MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nealkoholová steatóza jater * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Preclinical evidence suggests that n-3 fatty acids EPA and DHA (Omega-3) supplemented as phospholipids (PLs) may be more effective than triacylglycerols (TAGs) in reducing hepatic steatosis. To further test the ability of Omega-3 PLs to alleviate liver steatosis, we used a model of exacerbated non-alcoholic fatty liver disease based on high-fat feeding at thermoneutral temperature. Male C57BL/6N mice were fed for 24 weeks a lard-based diet given either alone (LHF) or supplemented with Omega-3 (30 mg/g diet) as PLs (krill oil; ω3PL) or TAGs (Epax 3000TG concentrate; ω3TG), which had a similar total content of EPA and DHA and their ratio. Substantial levels of TAG accumulation (~250 mg/g) but relatively low inflammation/fibrosis levels were achieved in the livers of control LHF mice. Liver steatosis was reduced by >40% in the ω3PL but not ω3TG group, and plasma ALT levels were markedly reduced (by 68%) in ω3PL mice as well. Krill oil administration also improved hepatic insulin sensitivity, and its effects were associated with high plasma adiponectin levels (150% of LHF mice) along with superior bioavailability of EPA, increased content of alkaloids stachydrine and trigonelline, suppression of lipogenic gene expression, and decreased diacylglycerol levels in the liver. This study reveals that in addition to Omega-3 PLs, other constituents of krill oil, such as alkaloids, may contribute to its strong antisteatotic effects in the liver.

• Klíčová slova
• C57BL/6N mice, NAFLD, high-fat diet, krill oil, obesity, omega-3, phospholipids, thermoneutral temperature,
• MeSH
• bydlení zvířat MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• Euphausiacea MeSH
• fosfolipidy farmakologie   MeSH
• fyziologie výživy zvířat MeSH
• inzulinová rezistence MeSH
• játra metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nealkoholová steatóza jater etiologie   terapie   MeSH
• obezita etiologie   terapie   MeSH
• potravní doplňky * MeSH
• rybí oleje farmakologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfolipidy MeSH
• rybí oleje MeSH

Long-chain n-3 polyunsaturated fatty acids (Omega-3) and anti-diabetic drugs thiazolidinediones (TZDs) exhibit additive effects in counteraction of dietary obesity and associated metabolic dysfunctions in mice. The underlying mechanisms need to be clarified. Here, we aimed to learn whether the futile cycle based on the hydrolysis of triacylglycerol and re-esterification of fatty acids (TAG/FA cycling) in white adipose tissue (WAT) could be involved. We compared Omega-3 (30 mg/g diet) and two different TZDs-pioglitazone (50 mg/g diet) and a second-generation TZD, MSDC-0602K (330 mg/g diet)-regarding their effects in C57BL/6N mice fed an obesogenic high-fat (HF) diet for 8 weeks. The diet was supplemented or not by the tested compound alone or with the two TZDs combined individually with Omega-3. Activity of TAG/FA cycle in WAT was suppressed by the obesogenic HF diet. Additive effects in partial rescue of TAG/FA cycling in WAT were observed with both combined interventions, with a stronger effect of Omega-3 and MSDC-0602K. Our results (i) supported the role of TAG/FA cycling in WAT in the beneficial additive effects of Omega-3 and TZDs on metabolism of diet-induced obese mice, and (ii) showed differential modulation of WAT gene expression and metabolism by the two TZDs, depending also on Omega-3.

• Klíčová slova
• adipocytes, glucose homeostasis, insulin, lipogenesis, obesity,
• MeSH
• bílá tuková tkáň metabolismus   MeSH
• dieta s vysokým obsahem tuků MeSH
• hypoglykemika farmakologie   MeSH
• lipogeneze účinky léků   MeSH
• mastné kyseliny metabolismus   MeSH
• metabolismus lipidů účinky léků   MeSH
• myši inbrední C57BL MeSH
• myši obézní MeSH
• myši MeSH
• obezita farmakoterapie   metabolismus   MeSH
• omega-3 mastné kyseliny aplikace a dávkování   farmakologie   MeSH
• pioglitazon farmakologie   MeSH
• thiazolidindiony aplikace a dávkování   farmakologie   MeSH
• triglyceridy metabolismus   MeSH
• tukové buňky účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hypoglykemika MeSH
• mastné kyseliny MeSH
• omega-3 mastné kyseliny MeSH
• pioglitazon MeSH
• thiazolidindiony MeSH
• triglyceridy MeSH

Antisteatotic effects of omega-3 fatty acids (Omega-3) in obese rodents seem to vary depending on the lipid form of their administration. Whether these effects could reflect changes in intestinal metabolism is unknown. Here, we compare Omega-3-containing phospholipids (krill oil; ω3PL-H) and triacylglycerols (ω3TG) in terms of their effects on morphology, gene expression and fatty acid (FA) oxidation in the small intestine. Male C57BL/6N mice were fed for 8 weeks with a high-fat diet (HFD) alone or supplemented with 30 mg/g diet of ω3TG or ω3PL-H. Omega-3 index, reflecting the bioavailability of Omega-3, reached 12.5% and 7.5% in the ω3PL-H and ω3TG groups, respectively. Compared to HFD mice, ω3PL-H but not ω3TG animals had lower body weight gain (-40%), mesenteric adipose tissue (-43%), and hepatic lipid content (-64%). The highest number and expression level of regulated intestinal genes was observed in ω3PL-H mice. The expression of FA ω-oxidation genes was enhanced in both Omega-3-supplemented groups, but gene expression within the FA β-oxidation pathway and functional palmitate oxidation in the proximal ileum was significantly increased only in ω3PL-H mice. In conclusion, enhanced intestinal FA oxidation could contribute to the strong antisteatotic effects of Omega-3 when administered as phospholipids to dietary obese mice.

• Klíčová slova
• Omega-3 index, Omega-3 phospholipids, high-fat diet, krill oil, small intestine,
• MeSH
• dieta s vysokým obsahem tuků * MeSH
• erytrocytární membrána metabolismus   MeSH
• Euphausiacea MeSH
• fosfolipidy aplikace a dávkování   MeSH
• krevní glukóza analýza   MeSH
• mastné kyseliny metabolismus   MeSH
• metabolismus lipidů účinky léků   MeSH
• myši obézní MeSH
• oleje MeSH
• omega-3 mastné kyseliny aplikace a dávkování   MeSH
• oxidace-redukce MeSH
• střeva anatomie a histologie   MeSH
• střevní sliznice metabolismus   MeSH
• tělesná hmotnost MeSH
• triglyceridy aplikace a dávkování   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfolipidy MeSH
• krevní glukóza MeSH
• mastné kyseliny MeSH
• oleje MeSH
• omega-3 mastné kyseliny MeSH
• triglyceridy MeSH

We found previously that white adipose tissue (WAT) hyperplasia in obese mice was limited by dietary omega-3 polyunsaturated fatty acids (omega-3 PUFA). Here we aimed to characterize the underlying mechanism. C57BL/6N mice were fed a high-fat diet supplemented or not with omega-3 PUFA for one week or eight weeks; mice fed a standard chow diet were also used. In epididymal WAT (eWAT), DNA content was quantified, immunohistochemical analysis was used to reveal the size of adipocytes and macrophage content, and lipidomic analysis and a gene expression screen were performed to assess inflammatory status. The stromal-vascular fraction of eWAT, which contained most of the eWAT cells, except for adipocytes, was characterized using flow cytometry. Omega-3 PUFA supplementation limited the high-fat diet-induced increase in eWAT weight, cell number (DNA content), inflammation, and adipocyte growth. eWAT hyperplasia was compromised due to the limited increase in the number of preadipocytes and a decrease in the number of endothelial cells. The number of leukocytes and macrophages was unaffected, but a shift in macrophage polarization towards a less inflammatory phenotype was observed. Our results document that the counteraction of eWAT hyperplasia by omega-3 PUFA in dietary-obese mice reflects an effect on the number of adipose lineage and endothelial cells.

• Klíčová slova
• adipocyte, cellularity, fat, nutrition, obesity, proliferation, white adipose tissue,
• MeSH
• bílá tuková tkáň účinky léků   MeSH
• dieta s vysokým obsahem tuků MeSH
• endoteliální buňky účinky léků   MeSH
• makrofágy účinky léků   patologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• omega-3 mastné kyseliny aplikace a dávkování   MeSH
• proliferace buněk účinky léků   MeSH
• tukové buňky cytologie   účinky léků   MeSH
• zánět patologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• omega-3 mastné kyseliny MeSH

Fatty acid esters of hydroxy fatty acids (FAHFAs) are lipid mediators with promising antidiabetic and anti-inflammatory properties that are formed in white adipose tissue (WAT) via de novo lipogenesis, but their biosynthetic enzymes are unknown. Using a combination of lipidomics in WAT, quantitative trait locus mapping, and correlation analyses in rat BXH/HXB recombinant inbred strains, as well as response to oxidative stress in murine models, we elucidated the potential pathway of biosynthesis of several FAHFAs. Comprehensive analysis of WAT samples identified ∼160 regioisomers, documenting the complexity of this lipid class. The linkage analysis highlighted several members of the nuclear factor, erythroid 2 like 2 (Nrf2)-mediated antioxidant defense system (Prdx6, Mgst1, Mgst3), lipid-handling proteins (Cd36, Scd6, Acnat1, Acnat2, Baat), and the family of flavin containing monooxygenases (Fmo) as the positional candidate genes. Transgenic expression of Nrf2 and deletion of Prdx6 genes resulted in reduction of palmitic acid ester of 9-hydroxystearic acid (9-PAHSA) and 11-PAHSA levels, while oxidative stress induced by an inhibitor of glutathione synthesis increased PAHSA levels nonspecifically. Our results indicate that the synthesis of FAHFAs via carbohydrate-responsive element-binding protein-driven de novo lipogenesis depends on the adaptive antioxidant system and suggest that FAHFAs may link activity of this system with insulin sensitivity in peripheral tissues.

• MeSH
• bílá tuková tkáň enzymologie   metabolismus   MeSH
• biologické markery metabolismus   MeSH
• estery chemie   metabolismus   MeSH
• faktor 2 související s NF-E2 genetika   metabolismus   MeSH
• krysa rodu Rattus MeSH
• kyselina palmitová chemie   metabolismus   MeSH
• kyseliny stearové chemie   metabolismus   MeSH
• metabolomika metody   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• náhodné rozdělení MeSH
• oxidační stres * MeSH
• peroxiredoxin VI genetika   metabolismus   MeSH
• potkani inbrední BN MeSH
• potkani inbrední SHR MeSH
• potkani transgenní MeSH
• regulace genové exprese enzymů * MeSH
• stanovení celkové genové exprese MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 9-hydroxystearic acid MeSH Prohlížeč
• biologické markery MeSH
• estery MeSH
• faktor 2 související s NF-E2 MeSH
• kyselina palmitová MeSH
• kyseliny stearové MeSH
• Nfe2l2 protein, mouse MeSH Prohlížeč
• Nfe2l2 protein, rat MeSH Prohlížeč
• peroxiredoxin VI MeSH
• Prdx6 protein, mouse MeSH Prohlížeč

Obesity is associated with insulin resistance and impaired glucose tolerance, which represent characteristic features of the metabolic syndrome. Development of obesity is also linked to changes in fatty acid and amino acid metabolism observed in animal models of obesity as well as in humans. The aim of this study was to explore whether plasma metabolome, namely the levels of various acylcarnitines and amino acids, could serve as a biomarker of propensity to obesity and impaired glucose metabolism. Taking advantage of a high phenotypic variation in diet-induced obesity in C57BL/6J mice, 12-week-old male and female mice (n = 155) were fed a high-fat diet (lipids ~32 wt%) for a period of 10 weeks, while body weight gain (BWG) and changes in insulin sensitivity (ΔHOMA-IR) were assessed. Plasma samples were collected before (week 4) and after (week 22) high-fat feeding. Both univariate and multivariate statistical analyses were then used to examine the relationships between plasma metabolome and selected phenotypes including BWG and ΔHOMA-IR. Partial least squares-discrimination analysis was able to distinguish between animals selected either for their low or high BWG (or ΔHOMA-IR) in male but not female mice. Among the metabolites that differentiated male mice with low and high BWG, and which also belonged to the major discriminating metabolites when analyzed in plasma collected before and after high-fat feeding, were amino acids Tyr and Orn, as well as acylcarnitines C16-DC and C18:1-OH. In general, the separation of groups selected for their low or high ΔHOMA-IR was less evident and the outcomes of a corresponding multivariate analysis were much weaker than in case of BWG. Thus, our results document that plasma acylcarnitines and amino acids could serve as a gender-specific complex biomarker of propensity to obesity, however with a limited predictive value in case of the associated impairment of insulin sensitivity.

• MeSH
• aminokyseliny krev   MeSH
• analýza rozptylu MeSH
• biologické markery MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• fenotyp MeSH
• glukózový toleranční test MeSH
• inzulinová rezistence MeSH
• karnitin analogy a deriváty   krev   MeSH
• krevní glukóza MeSH
• metabolom MeSH
• metabolomika metody   MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• obezita krev   diagnóza   etiologie   MeSH
• porucha glukózové tolerance MeSH
• prognóza MeSH
• shluková analýza MeSH
• tendenční skóre MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acylcarnitine MeSH Prohlížeč
• aminokyseliny MeSH
• biologické markery MeSH
• karnitin MeSH
• krevní glukóza MeSH

Poly-unsaturated fatty acids (PUFAs) are considered to be healthier than saturated fatty acids (SFAs), but others postulate that especially the ratio of omega-6 to omega-3 PUFAs (n6/n3 ratio) determines health. Health can be determined with biomarkers, but functional health status is likely better reflected by challenge tests that assess metabolic flexibility. The aim of this study was to determine the effect of high-fat diets with different fatty acid compositions, but similar n6/n3 ratio, on metabolic flexibility. Therefore, adult male mice received isocaloric high-fat diets with either predominantly PUFAs (HFpu diet) or predominantly SFAs (HFs diet) but similar n6/n3 ratio for six months, during and after which several biomarkers for health were measured. Metabolic flexibility was assessed by the response to an oral glucose tolerance test, a fasting and re-feeding test and an oxygen restriction test (OxR; normobaric hypoxia). The latter two are non-invasive, indirect calorimetry-based tests that measure the adaptive capacity of the body as a whole. We found that the HFs diet, compared to the HFpu diet, increased mean adipocyte size, liver damage, and ectopic lipid storage in liver and muscle; although, we did not find differences in body weight, total adiposity, adipose tissue health, serum adipokines, whole body energy balance, or circadian rhythm between HFs and HFpu mice. HFs mice were, furthermore, less flexible in their response to both fasting- re-feeding and OxR, while glucose tolerance was indistinguishable. To conclude, the HFs versus the HFpu diet increased ectopic fat storage, liver damage, and mean adipocyte size and reduced metabolic flexibility in male mice. This study underscores the physiological relevance of indirect calorimetry-based challenge tests.

• MeSH
• adipozita MeSH
• dieta s vysokým obsahem tuků MeSH
• energetický metabolismus fyziologie   MeSH
• glukózový toleranční test MeSH
• hypoxie MeSH
• játra cytologie   metabolismus   MeSH
• kosterní svaly metabolismus   MeSH
• kyseliny mastné omega-6 metabolismus   MeSH
• metabolismus lipidů MeSH
• mitochondrie fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• omega-3 mastné kyseliny metabolismus   MeSH
• tuková tkáň metabolismus   MeSH
• tukové buňky metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyseliny mastné omega-6 MeSH
• omega-3 mastné kyseliny MeSH

Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive "energy conserves". Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.

• MeSH
• lidé MeSH
• lipasa metabolismus   MeSH
• mastné kyseliny genetika   metabolismus   MeSH
• orgánová specificita MeSH
• signální transdukce * MeSH
• transkripční faktory metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• lipasa MeSH
• mastné kyseliny MeSH
• transkripční faktory MeSH