Isomer-specific regulation of metabolism and PPARgamma signaling by CLA in human preadipocytes

Digestive interaction between dietary nitrite and dairy products generates novel nitrated linolenic acid products

Nitrated fatty acids are important anti-inflammatory and protective lipids formed in the gastric compartment, with conjugated linoleic acid (rumenic acid, RA, 9Z,11E-18:2) being the primary substrate for lipid nitration. The recently reported identification of nitrated rumelenic acid (NO2-RLA) in human urine has led to hypothesize that rumelenic acid (RLA, 9Z,11E,15Z-18:3) from dairy fat is responsible for the formation of NO2-RLA. To evaluate the source and mechanism of NO2-RLA formation, 15N labeled standards of NO2-RLA were synthesized and characterized. Afterward, milk fat with different RA and RLA levels was administered to mice in the presence of nitrite, and the appearance of nitrated fatty acids in plasma and urine followed. We confirmed the formation of NO2-RLA and defined the main metabolites in plasma, urine, and tissues. In conclusion, RLA obtained from dairy products is the main substrate for forming this novel electrophilic lipid reported to be present in human urine.

A Cardiac Amino-Terminal GRK2 Peptide Inhibits Maladaptive Adipocyte Hypertrophy and Insulin Resistance During Diet-Induced Obesity

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Heart disease remains the leading cause of death, in part due to increasing diabetes and obesity, though the exact mechanisms linking these disorders are not fully understood.

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In a diet-induced obesity model, we found that cardiac expression of an amino-terminal peptide of GRK2, βARKnt, preserves systemic glucose tolerance and insulin sensitivity despite normal weight gain.

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βARKnt enhanced metabolic flexibility, increased energy expenditure, protected against maladaptive visceral adipocyte hypertrophy, and induced visceral fat browning.

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βARKnt further elicited cardioprotection and increased insulin-mediated AS160 signaling during metabolic stress.

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These data point to a noncanonical cardiac regulation of systemic metabolic homeostasis that may lead to new treatment modalities for metabolic syndrome.

Heart disease remains the leading cause of death, and mortality rates positively correlate with the presence of obesity and diabetes. Despite the correlation between cardiac and metabolic dysregulation, the mechanistic pathway(s) of interorgan crosstalk still remain undefined. This study reveals that cardiac-restricted expression of an amino-terminal peptide of GRK2 (βARKnt) preserves systemic and cardiac insulin responsiveness, and protects against adipocyte maladaptive hypertrophy in a diet-induced obesity model. These data suggest a cardiac-driven mechanism to ameliorate maladaptive cardiac remodeling and improve systemic metabolic homeostasis that may lead to new treatment modalities for cardioprotection in obesity and obesity-related metabolic syndromes.

Involvement of Gut Microbial Metabolites Derived from Diet on Host Energy Homeostasis

Due to the excess energy intake, which is a result of a high fat and high carbohydrate diet, dysfunction of energy balance leads to metabolic disorders such as obesity and type II diabetes mellitus (T2DM). Since obesity can be a risk factor for various diseases, including T2DM, hypertension, hyperlipidemia, and metabolic syndrome, novel prevention and treatment are expected. Moreover, host diseases linked to metabolic disorders are associated with changes in gut microbiota profile. Gut microbiota is affected by diet, and nutrients are used as substrates by gut microbiota for produced metabolites, such as short-chain and long-chain fatty acids, that may modulate host energy homeostasis. These free fatty acids are not only essential energy sources but also signaling molecules via G-protein coupled receptors (GPCRs). Some GPCRs are critical for metabolic functions, such as hormone secretion and immune function in various types of cells and tissues and contribute to energy homeostasis. The current studies have shown that GPCRs for gut microbial metabolites improved host energy homeostasis and systemic metabolic disorders. Here, we will review the association between diet, gut microbiota, and host energy homeostasis.

Effects of in ovo feeding of t10,c12-conjugated linoleic acid on hepatic lipid metabolism and subcutaneous adipose tissue deposition in newly hatched broiler chicks

The purpose of this study was to investigate whether in ovo feeding of t10,c12-conjugated linoleic acid (CLA) could regulate hepatic lipid metabolism and decrease lipid accumulation in newly hatched chicks. Three hundred and sixty fertilely specific pathogen-free hatching eggs were selected and randomly divided into 6 groups. On embryonic day 11 of incubation (E11), 0, 1.5, 3.0, 4.5, 6.0, or 7.5 mg t10,c12-CLA were injected into the eggs. The results indicated that in ovo feeding of t10,c12-CLA significantly decreased the subcutaneous adipose tissue (SAT) mass and the relative SAT weight of newly hatched chicks in linear and quadratic manners (P < 0.05). In liver, the levels of triglycerides were reduced linearly and quadratically and total cholesterol were reduced quadratically as the dose of t10,c12-CLA increased (P < 0.05). Meanwhile, the hepatic carnitine palmitoyltransferase-1a (CPT1a) content and polyunsaturated fatty acid proportion were increased quadratically in t10,c12-CLA groups (P < 0.05), accompanied by the decrease of malondialdehyde level and the increase of glutathione peroxidase and total antioxidant capacity activities (P < 0.05). In addition, in ovo feeding of t10,c12-CLA decreased the mRNA expression levels of fatty acid synthase, acetyl-CoA carboxylase 1 in linear and quadratic manners (P < 0.05), and decreased the mRNA expression of adipose triacylglyceride lipase and stearoyl-CoA desaturase significantly in liver (P < 0.05), accompanied by upregulating the mRNA expression of CPT1a quadratically and AMP-activated protein kinase α linearly and quadratically (P < 0.05). In SAT, the mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ) and sterol regulatory element-binding protein-1c were decreased linearly and quadratically (P < 0.05), and the expression of PPARα and CPT1a genes were increased linearly and quadratically as the dose of t10,c12-CLA increased (P < 0.05). In conclusion, our findings demonstrate that in ovo feeding of t10,c12-CLA alleviates lipid accumulation in newly hatched chicks by suppressing fatty acid synthesis and stimulating lipolysis in the liver and inhibiting adipocyte differentiation in subcutaneous adipose tissue.

Mechanisms of Anticancer Activity of a Fatty Acid Mixture Extracted from Hen Egg Yolks Enriched in Conjugated Linoleic Acid Diene (CLA) against WM793 Melanoma Cells

The conjugated linoleic acid (CLA) diene is a biologically active compound with proven health-promoting effects. In terms of anticancer properties, it has been shown that CLA reduces the proliferation of cancer cells. In this study, it has been demonstrated that a mixture of fatty acids, isolated from chicken egg yolk enriched in CLA isomers by biofortification, reduces (by 30.5%) the proliferation of human melanoma cancer cells line WM793 to a greater extent than a mixture of fatty acids not containing these isomers. At the same time, the tested fatty acid mixtures show no effect on human normal BJ fibroblast cells. For the first time, the genes with increased expression have been identified and the proteins have been activated by the fatty acid mixture of CLA-enriched egg yolk, mainly responsible for mitochondrial pathway-dependent apoptosis.

Long term conjugated linoleic acid supplementation modestly improved growth performance but induced testicular tissue apoptosis and reduced sperm quality in male rabbit

Conjugated linoleic acid (CLA) is known for its multiple benefits including improvement of growth, increasing lean mass, and anti-carcinogenic effects. However, when used in long-term supplementations CLA does not improve semen parameters in boar and bull and reduces fertility in Japanese quails. The content of unsaturated fatty acids in dietary lipids plays a significant role in spermatogenesis owning the high proportion of unsaturated fatty acids in plasma membrane of sperms. Whether CLA plays a role in testicular tissue and epididymal fat is still unknown. Therefore, in this study we hypothesize that long-term supplementation of equal proportion of CLA isomer mix (c9,t11-CLA and t10,c12- CLA) in rabbit bucks might alter male reproductive potentials. Twelve V-Line weaned male rabbits were used in 26 weeks trial, rabbits were individually raised and randomly allocated into three dietary groups. Control group (CON) received a basal diet, a group received 0.5% CLA (CLA 0.5%), and a group received 1% CLA (CLA 1%). Rabbits were euthanized at the end of the trial and several parameters were evaluated related to growth, semen quality, and testicular and epididymal tissue histopathology and transcriptome. The long-term supplementation of CLA increased feed intake by 5% and body weight by 2-3%. CLA 1% decreased sperm progressive motility. In testicular tissue L-carnitine and α-tocopherol were decreased by CLA supplementation. In epididymal fat, CLA tended to decrease concentration of polyunsaturated fatty acids, the expression of SCD5 gene was upregulated by CLA 1% and CASP3 gene was upregulated by CLA 0.5%. Transcription of PPARG was downregulated by CLA. Feeding 1% CLA also decreased testicular epithelial thickness. Long-term supplementation of CLA modestly enhanced male rabbit growth, but negatively impacted male reproduction, especially at high dose of CLA.

Obesity-linked suppression of membrane-bound O-acyltransferase 7 (MBOAT7) drives non-alcoholic fatty liver disease

Recent studies have identified a genetic variant rs641738 near two genes encoding membrane bound O-acyltransferase domain-containing 7 (MBOAT7) and transmembrane channel-like 4 (TMC4) that associate with increased risk of non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), alcohol-related cirrhosis, and liver fibrosis in those infected with viral hepatitis (Buch et al., 2015; Mancina et al., 2016; Luukkonen et al., 2016; Thabet et al., 2016; Viitasalo et al., 2016; Krawczyk et al., 2017; Thabet et al., 2017). Based on hepatic expression quantitative trait loci analysis, it has been suggested that MBOAT7 loss of function promotes liver disease progression (Buch et al., 2015; Mancina et al., 2016; Luukkonen et al., 2016; Thabet et al., 2016; Viitasalo et al., 2016; Krawczyk et al., 2017; Thabet et al., 2017), but this has never been formally tested. Here we show that Mboat7 loss, but not Tmc4, in mice is sufficient to promote the progression of NAFLD in the setting of high fat diet. Mboat7 loss of function is associated with accumulation of its substrate lysophosphatidylinositol (LPI) lipids, and direct administration of LPI promotes hepatic inflammatory and fibrotic transcriptional changes in an Mboat7-dependent manner. These studies reveal a novel role for MBOAT7-driven acylation of LPI lipids in suppressing the progression of NAFLD.

Host- and Microbe-Dependent Dietary Lipid Metabolism in the Control of Allergy, Inflammation, and Immunity

The intestine is the largest immune organ in the body, provides the first line of defense against pathogens, and prevents excessive immune reactions to harmless or beneficial non-self-materials, such as food and intestinal bacteria. Allergic and inflammatory diseases in the intestine occur as a result of dysregulation of immunological homeostasis mediated by intestinal immunity. Several lines of evidence suggest that gut environmental factors, including nutrition and intestinal bacteria, play important roles in controlling host immune responses and maintaining homeostasis. Among nutritional factors, ω3 and ω6 essential polyunsaturated fatty acids (PUFAs) profoundly influence the host immune system. Recent advances in lipidomics technology have led to the identification of lipid mediators derived from ω3- and ω6-PUFAs. In particular, lipid metabolites from ω3-PUFAs (e.g., eicosapentaenoic acid and docosahexaenoic acid) have recently been shown to exert anti-allergic and anti-inflammatory responses; these metabolites include resolvins, protectins, and maresins. Furthermore, a new class of anti-allergic and anti-inflammatory lipid metabolites of 17,18-epoxyeicosatetraenoic acid has recently been identified in the control of allergic and inflammatory diseases in the gut and skin. Although these lipid metabolites were found to be endogenously generated in the host, accumulating evidence indicates that intestinal bacteria also participate in lipid metabolism and thus generate bioactive unique lipid mediators. In this review, we discuss the production machinery of lipid metabolites in the host and intestinal bacteria and the roles of these metabolites in the regulation of host immunity.

Conjugated Linoleic Acid Effects on Cancer, Obesity, and Atherosclerosis: A Review of Pre-Clinical and Human Trials with Current Perspectives

Obesity and its comorbidities, including type 2 diabetes and cardiovascular disease, are straining our healthcare system, necessitating the development of novel strategies for weight loss. Lifestyle modifications, such as exercise and caloric restriction, have proven effective against obesity in the short term, yet obesity persists because of the high predilection for weight regain. Therefore, alternative approaches to achieve long term sustainable weight loss are urgently needed. Conjugated linoleic acid (CLA), a fatty acid found naturally in ruminant animal food products, has been identified as a potential anti-obesogenic agent, with substantial efficacy in mice, and modest efficacy in obese human populations. Originally described as an anti-carcinogenic fatty acid, in addition to its anti-obesogenic effects, CLA has now been shown to possess anti-atherosclerotic properties. This review summarizes the pre-clinical and human studies conducted using CLA to date, which collectively suggest that CLA has efficacy against cancer, obesity, and atherosclerosis. In addition, the potential mechanisms for the many integrative physiological effects of CLA supplementation will be discussed in detail, including an introduction to the gut microbiota as a potential mediator of CLA effects on obesity and atherosclerosis.

Intestine-Specific Overexpression of Carboxylesterase 2c Protects Mice From Diet-Induced Liver Steatosis and Obesity

Murine hepatic carboxylesterase 2c (Ces2c) and the presumed human ortholog carboxylesterase 2 (CES2) have been implicated in the development of nonalcoholic fatty liver disease (NAFLD) in mice and obese humans. These studies demonstrated that Ces2c hydrolyzes triglycerides (TGs) in hepatocytes. Interestingly, Ces2c/CES2 is most abundantly expressed in the intestine, indicating a role of Ces2c/CES2 in intestinal TG metabolism. Here we show that Ces2c is an important enzyme in intestinal lipid metabolism in mice. Intestine-specific Ces2c overexpression (Ces2c^int) provoked increased fatty acid oxidation (FAO) in the small intestine accompanied by enhanced chylomicron clearance from the circulation. As a consequence, high-fat diet-fed Ces2c^int mice were resistant to excessive diet-induced weight gain and adipose tissue expansion. Notably, intestinal Ces2c overexpression increased hepatic insulin sensitivity and protected mice from NAFLD development. Although lipid absorption was not affected in Ces2c^int mice, fecal energy content was significantly increased. Mechanistically, we demonstrate that Ces2c is a potent neutral lipase, which efficiently hydrolyzes TGs and diglycerides (DGs) in the small intestine, thereby generating fatty acids (FAs) for FAO and monoglycerides (MGs) and DGs for potential re-esterification. Consequently, the increased availability of MGs and DGs for re-esterification and primordial apolipoprotein B₄₈ particle lipidation may increase chylomicron size, ultimately mediating more efficient chylomicron clearance from the circulation. Conclusion: This study suggests a critical role for Ces2c in intestinal lipid metabolism and highlights the importance of intestinal lipolysis to protect mice from the development of hepatic insulin resistance, NAFLD, and excessive diet-induced weight gain during metabolic stress.

Conjugated linoleic acid enriched skim milk prepared with Lactobacillus fermentum DDHI27 endorsed antiobesity in mice

Aim: This study evaluated the antiobesity effect of skim milk prepared with conjugated linoleic acid producing probiotic Lactobacillus fermentum DDHI27 (PCLA). Materials & methods: C57BL/6 J mice were divided into five groups, and different obesity-associated parameters were studied. Results: PCLA supplementation alleviated body weight, epididymal and mesenteric fats and improves lipid profiles. Significant ameliorations in leptin, blood glucose, hepatic steatosis and reduction in adipocytes size were also observed. Additionally, feeding also led to positive alterations in the adipogenesis transcription factors and key lipogenesis genes. Improvement in the gut microbiota dysbiosis was also revealed. Conclusion: Results inferred that PCLA exerted an antiobesity effect in diet-induced obese mice and may be further developed in the functional foods for the management of obesity.

Dietary supplement of conjugated linoleic acids or polyunsaturated fatty acids suppressed the mobilization of body fat reserves in dairy cows at early lactation through different pathways

To investigate the metabolic changes in the adipose tissue (AT) of dairy cows under milk fat depression (MFD), 30 cows were randomly allocated to a control diet, a conjugated linoleic acid (CLA)-supplemented diet, or a high-starch diet supplemented with a mixture of sunflower and fish oil (2:1; as HSO diet) from 1 to 112 d in milk. Performance of animals, milk yield, milk composition, energy balance, and blood metabolites were measured during lactation. Quantitative PCR analyses were conducted on the AT samples collected at wk 3 and 15 of lactation. The CLA and HSO diets considerably depressed milk fat yield and milk fat content at both wk 3 and 15 in the absence of significant changes in milk protein and lactose contents. In addition, the HSO diet lowered milk yield at wk 15 and decreased dry matter intake of cows from wk 3 to 15. Compared with the control, both CLA and HSO groups showed reduced body weight loss, improved energy balance, and decreased plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate at early lactation. The gene expression analyses reflected suppressed lipolysis in AT of the CLA and HSO groups compared with the control at wk 3, as suggested by the downregulation of hormone-sensitive lipase and fatty acid binding protein 4 and the upregulation of perilipin 2. In addition, the HSO diet promoted lipogenesis in AT at wk 15 through the upregulation of 1-acylglycerol-3-phosphate O-acyltransferase 2, mitochondrial glycerol-3-phosphate acyltransferase, perilipin 2, and peroxisome proliferator-activated receptor γ. The CLA diet likely regulated insulin sensitivity in AT as it upregulated the transcription of various genes involved in insulin signaling, inflammatory responses, and ceramide metabolism, including protein kinase B2, nuclear factor κ B1, toll-like receptor 4, caveolin 1, serine palmitoyltransferase long chain base subunit 1, and N-acylsphingosine amidohydrolase 1. In contrast, the HSO diet resulted in little or no change in the pathways relevant to insulin sensitivity. In conclusion, the CLA and HSO diets induced a shift in energy partitioning toward AT instead of mammary gland during lactation through the regulation of different pathways.

Gut microbiota and mTOR signaling: Insight on a new pathophysiological interaction

The gut microbiota plays a substantial role in regulating the host metabolic and immune functions. Dysbiosis, resulting from disruption of gut microbiota, predisposes many morbid pathologies like obesity and its associated comorbidities, diabetes and inflammatory conditions including some types of cancer. There are numerous proposed signaling pathways through which alterations in gut microbiota and its metabolites can disturb the host's normal physiological functions. Interestingly, many of these processes happen to be controlled by the mammalian target of rapamycin (mTOR). The mTOR pathway responds to environmental changes and regulates accordingly many intracellular processes such as transcription, translation, cell growth, cytoskeletal organization and autophagy. In this review, we aim to highlight the cross-talk between the gut microbiota and the mTOR pathway and discuss how this emerging field of research gives a beautiful insight into how the mentioned cross-talk impacts the body's homeostasis thus leading to undesirable complications including obesity, diabetes, colon and pancreatic cancer, immune system malfunctioning and ageing. Although there are a limited number of studies investigating the crosstalk between the gut microbiota and the mTOR pathway, the results obtained so far are enough to elucidate the key role of the mTOR signaling in microbiota-associated metabolic and immune regulations.

Bioconversion of conjugated linoleic acid by Lactobacillus plantarum CGMCC8198 supplemented with Acer truncatum bunge seeds oil

Conjugated linoleic acid (CLA) isomers, c9, t11-CLA and t10, c12-CLA, have been proved to exhibit excellent biomedical properties for potential use in anti-cancer applications and in reducing obesity. Acer truncatum Bunge (ATB), which is rich in unsaturated fatty acids, including oleic acid, linoleic acid, and nervonic acid, is a new resource for edible oil. In the present study, we developed a new method for producing two CLA isomers from ATB-seed oil by fermentation using Lactobacillus plantarum CGMCC8198 (LP8198), a novel probiotics strain. Polymerase chain reaction results showed that there was a conserved linoleate isomerase (LIase) gene in LP8198, and its transcription could be induced by ATB-seed oil. Analyses by gas chromatography-mass spectrometry showed that the concentration of c9, t11-CLA and t10, c12-CLA in ATB-seed oil could be increased by about 9- and 2.25-fold, respectively, after being fermented by LP8198.

Characterization of the triple-component linoleic acid isomerase in Lactobacillus plantarum ZS2058 by genetic manipulation

AIM

To assess the mechanism for conjugated linoleic acid (CLA) production in Lactobacillus plantarum ZS2058.

METHODS AND RESULTS

CLA has attracted great interests for decades due to its health-associated benefits including anticancer, anti-atherogenic, anti-obesity and modulation of the immune system. A number of microbial CLA producers were widely reported including lactic acid bacteria. Lactobacillus plantarum ZS2058, an isolate from Chinese traditional fermented food, could convert LA to CLA with various intermediates. To characterize the genetic determinants for generating CLA, a cre-lox-based system was utilized to delete the genes encoding myosin cross-reactive antigen (MCRA), short-chain dehydrogenase/oxidoreductase (DH) and acetoacetate decarboxylase (DC) in Lact. plantarum ZS2058, respectively. Neither intermediate was detected in the corresponding gene deletion mutant. Meanwhile all those mutants could recover the ability to convert linoleic acid to CLA when the corresponding gene was completed.

CONCLUSIONS

The results indicated that CLA production was a multiple-step reaction catalysed by triple-component linoleate isomerase system encoded by mcra, dh and dc.

SIGNIFICANCE AND IMPACT OF THE STUDY

Multicomponent linoleic acid isomerase provided important results for illustration unique mechanism for CLA production in Lact. plantarum ZS2058. Lactobacilli with CLA production ability offer novel opportunities for functional food development.

Nutrient Regulation: Conjugated Linoleic Acid's Inflammatory and Browning Properties in Adipose Tissue

Obesity is the most widespread nutritional disease in the United States. Developing effective and safe strategies to manage excess body weight is therefore of paramount importance. One potential strategy to reduce obesity is to consume conjugated linoleic acid (CLA) supplements containing isomers cis-9, trans-11 and trans-10, cis-12, or trans-10, cis-12 alone. Proposed antiobesity mechanisms of CLA include regulation of (a) adipogenesis, (b) lipid metabolism, (c) inflammation, (d) adipocyte apoptosis, (e) browning or beiging of adipose tissue, and (f) energy metabolism. However, causality of CLA-mediated responses to body fat loss, particularly the linkage between inflammation, thermogenesis, and energy metabolism, is unclear. This review examines whether CLA's antiobesity properties are due to inflammatory signaling and considers CLA's linkage with lipogenesis, lipolysis, thermogenesis, and browning of white and brown adipose tissue. We propose a series of questions and studies to interrogate the role of the sympathetic nervous system in mediating CLA's antiobesity properties.

The trans-10,cis-12 conjugated linoleic acid increases triacylglycerol hydrolysis in yeast Saccharomyces cerevisiae

AIMS

The trans-10,cis-12 conjugated linoleic acid (CLA) is known for its antilipogenic effect but the mechanism is not fully clear. In this study, the potential of yeast (Saccharomyces cerevisiae) metabolism to offer evidence for the mechanism was investigated.

METHODS AND RESULTS

The inhibitory effect of CLA on lipid accumulation was studied by analysing the transcript abundance of selected genes involved in triacylglycerol synthesis (LRO1, DGA1, ARE1 and ARE2) in the presence of the two bioactive CLA isomers: trans-10,cis-12 and the cis-9,trans-11 CLA. None of the enzymes was reduced in transcription but the expression of ARE2 was induced by trans-10,cis-12 CLA. However, the ARE2 overexpression did not contribute to lipid accumulation. The expression of the Δ9 desaturase gene, OLE1, was reduced by the cis-9,trans-11 but not by the trans-10,cis-12 isomer. In the TGL3/TGL4-knockout strain the triacylglycerol content also remained high in the CLA fed cells.

CONCLUSIONS

Triacylglycerol hydrolysis rather than synthesis was the most probable reason for the reduced lipid content in yeast induced by CLA.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study revealed new aspects of the functionality of CLA in eukaryotic lipid metabolism. Yeast was proven to be an applicable model to study further the mechanism of trans-10,cis-12 CLA functionality on lipid metabolism.

Fatty Acids Have Different Adipogenic Differentiation Potentials in Stromal Vascular Cells Isolated from Abdominal Fat in Laying Hens

This study was conducted to examine the effects of fatty acids (FA) with/without chicken serum (CS) on the expression of adipogenic transcripts and adipogenesis in chicken stromal vascular cells (SVC). In experiment 1, SVC were grown in DMEM containing 10% FBS (Control) and treated with 300 µM oleic acid (OLA) + FBS, linoleic acid (LNA) + FBS, palmitic acid (PAM) + FBS, or stearic acid (STA) + FBS for 48 h. In experiment 2, cells were grown in DMEM containing 5% CS and treated with 300 µM OLA (CS + OLA), PAM (CS + PAM), STA (CS + STA) or 200 µM LNA (CS + LNA) for 48 h. Adipogenesis was determined using Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity. The proportion of OLA, PAM, or STA was increased (P < 0.05) in SVC grown in either FBS or CS with OLA, PAM or STA. Adipogenesis was induced in FBS + OLA, FBS + LNA, FBS + PAM, FBS + STA, CS + OLA, CS + LNA, CS + PAM, or CS + SAT compared to FBS. GPDH activity was significantly higher in FBS + OLA and FBS + LNA than one in FBS. Compared to FBS, the expression of FABP4 mRNA increased (P < 0.05) in FBS + OLA, FBS + LNA, or FBS + PAM, whereas that of C/EBPα, C/EBPβ, and ATGL increased (P < 0.05) in FBS + OLA or FBS + LNA cells. Expression of FABP4 and C/EBPβ mRNA was higher in CS, CS + OLA, CS + LNA, CS + PAM, or CS + SAT compared with (FBS, whereas the expression of ATGL and C/EBPα was higher in CS, CS + OLA, or CS + LNA than FBS cells. In conclusion, these results showed that FA have different potentials to induce adipogenesis, LNA is the most potent among the tested FA, and these potentials can be improved in the presence of CS.

Pyruvate kinase M2 activation may protect against the progression of diabetic glomerular pathology and mitochondrial dysfunction

Diabetic nephropathy (DN) is a major cause of end-stage renal disease, and therapeutic options for preventing its progression are limited. To identify novel therapeutic strategies, we studied protective factors for DN using proteomics on glomeruli from individuals with extreme duration of diabetes (ł50 years) without DN and those with histologic signs of DN. Enzymes in the glycolytic, sorbitol, methylglyoxal and mitochondrial pathways were elevated in individuals without DN. In particular, pyruvate kinase M2 (PKM2) expression and activity were upregulated. Mechanistically, we showed that hyperglycemia and diabetes decreased PKM2 tetramer formation and activity by sulfenylation in mouse glomeruli and cultured podocytes. Pkm-knockdown immortalized mouse podocytes had higher levels of toxic glucose metabolites, mitochondrial dysfunction and apoptosis. Podocyte-specific Pkm2-knockout (KO) mice with diabetes developed worse albuminuria and glomerular pathology. Conversely, we found that pharmacological activation of PKM2 by a small-molecule PKM2 activator, TEPP-46, reversed hyperglycemia-induced elevation in toxic glucose metabolites and mitochondrial dysfunction, partially by increasing glycolytic flux and PGC-1α mRNA in cultured podocytes. In intervention studies using DBA2/J and Nos3 (eNos) KO mouse models of diabetes, TEPP-46 treatment reversed metabolic abnormalities, mitochondrial dysfunction and kidney pathology. Thus, PKM2 activation may protect against DN by increasing glucose metabolic flux, inhibiting the production of toxic glucose metabolites and inducing mitochondrial biogenesis to restore mitochondrial function.

Conjugated Linoleic Acid Administration Induces Amnesia in Male Sprague Dawley Rats and Exacerbates Recovery from Functional Deficits Induced by a Controlled Cortical Impact Injury

Long-chain polyunsaturated fatty acids like conjugated linoleic acids (CLA) are required for normal neural development and cognitive function and have been ascribed various beneficial functions. Recently, oral CLA also has been shown to increase testosterone (T) biosynthesis, which is known to diminish traumatic brain injury (TBI)-induced neuropathology and reduce deficits induced by stroke in adult rats. To test the impact of CLA on cognitive recovery following a TBI, 5-6 month old male Sprague Dawley rats received a focal injury (craniectomy + controlled cortical impact (CCI; n = 17)) or Sham injury (craniectomy alone; n = 12) and were injected with 25 mg/kg body weight of Clarinol® G-80 (80% CLA in safflower oil; n = 16) or saline (n = 13) every 48 h for 4 weeks. Sham surgery decreased baseline plasma progesterone (P4) by 64.2% (from 9.5 ± 3.4 ng/mL to 3.4 ± 0.5 ng/mL; p = 0.068), T by 74.6% (from 5.9 ± 1.2 ng/mL to 1.5 ± 0.3 ng/mL; p < 0.05), 11-deoxycorticosterone (11-DOC) by 37.5% (from 289.3 ± 42.0 ng/mL to 180.7 ± 3.3 ng/mL), and corticosterone by 50.8% (from 195.1 ± 22.4 ng/mL to 95.9 ± 2.2 ng/mL), by post-surgery day 1. CCI injury induced similar declines in P4, T, 11-DOC and corticosterone (58.9%, 74.6%, 39.4% and 24.6%, respectively) by post-surgery day 1. These results suggest that both Sham surgery and CCI injury induce hypogonadism and hypoadrenalism in adult male rats. CLA treatment did not reverse hypogonadism in Sham (P4: 2.5 ± 1.0 ng/mL; T: 0.9 ± 0.2 ng/mL) or CCI-injured (P4: 2.2 ± 0.9 ng/mL; T: 1.0 ± 0.2 ng/mL, p > 0.05) animals by post-injury day 29, but rapidly reversed by post-injury day 1 the hypoadrenalism in Sham (11-DOC: 372.6 ± 36.6 ng/mL; corticosterone: 202.6 ± 15.6 ng/mL) and CCI-injured (11-DOC: 384.2 ± 101.3 ng/mL; corticosterone: 234.6 ± 43.8 ng/mL) animals. In Sham surgery animals, CLA did not alter body weight, but did markedly increase latency to find the hidden Morris Water Maze platform (40.3 ± 13.0 s) compared to saline treated Sham animals (8.8 ± 1.7 s). In CCI injured animals, CLA did not alter CCI-induced body weight loss, CCI-induced cystic infarct size, or deficits in rotarod performance. However, like Sham animals, CLA injections exacerbated the latency of CCI-injured rats to find the hidden MWM platform (66.8 ± 10.6 s) compared to CCI-injured rats treated with saline (30.7 ± 5.5 s, p < 0.05). These results indicate that chronic treatment of CLA at a dose of 25 mg/kg body weight in adult male rats over 1-month 1) does not reverse craniectomy- and craniectomy + CCI-induced hypogonadism, but does reverse craniectomy- and craniectomy + CCI-induced hypoadrenalism, 2) is detrimental to medium- and long-term spatial learning and memory in craniectomized uninjured rats, 3) limits cognitive recovery following a moderate-severe CCI injury, and 4) does not alter body weight.

Nutrigenomics and Beef Quality: A Review about Lipogenesis

The objective of the present review is to discuss the results of published studies that show how nutrition affects the expression of genes involved in lipid metabolism and how diet manipulation might change marbling and composition of fat in beef. Several key points in the synthesis of fat in cattle take place at the molecular level, and the association of nutritional factors with the modulation of this metabolism is one of the recent targets of nutrigenomic research. Within this context, special attention has been paid to the study of nuclear receptors associated with fatty acid metabolism. Among the transcription factors involved in lipid metabolism, the peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding proteins (SREBPs) stand out. The mRNA synthesis of these transcription factors is regulated by nutrients, and their metabolic action might be potentiated by diet components and change lipogenesis in muscle. Among the options for dietary manipulation with the objective to modulate lipogenesis, the use of different sources of polyunsaturated fatty acids, starch concentrations, forage ratios and vitamins stand out. Therefore, special care must be exercised in feedlot feed management, mainly when the goal is to produce high marbling beef.

Trans-10,cis-12 conjugated linoleic acid (CLA) interferes with lipid droplet accumulation during 3T3-L1 preadipocyte differentiation

In this study, we hypothesize that the biologically active isomers of conjugated linoleic acid (CLA), cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) CLA, have different effects on early and late stages 3T3-L1 preadipocyte differentiation. Both c9-t11 and t10-c12CLA stimulated early stage pre-adipocyte differentiation (day 2), while t10-c12CLA inhibited late differentiation (day 8) as determined by lipid droplet numbers and both perilipin-1 levels and phosphorylation state. At day 8, the adipokines adiponectin, chemerin and adipsin were all reduced in t10-c12CLA treated cells versus control cells. Immunofluorescence microscopy showed perilipin-1 was present solely on lipid droplets on day 8 in t10-c12 treated 3T3-L1 cells, whereas preilipin-1 was also located in the perinuclear region in control and c9-t11 treated cells. The t10-c12CLA isomer also decreased levels of hormone-sensitive lipase and inhibited lipolysis. These findings indicate that the decrease in lipid droplets caused by t10-c12CLA is the result of an inhibition of lipid droplet production during adipogenesis rather than a stimulation of lipolysis. Additionally, treatment with Gö6976 blocked the effect of t10-c12CLA on perilipin-1 phosphorylation, implicating PKCα in perilipin-1 phosphorylation, and thus a regulator of triglyceride catabolism. These data are supported by evidence that t10-c12CLA activated PKCα. These are the first data to show that CLA isomers can affect lipid droplet dynamics in adipocytes through PKCα.

Conjugated linoleic acid mitigates testosterone-related changes in body composition in male guinea pigs

We hypothesize that conjugated linoleic acid (CLA) may be effective in preventing the changes in total and regional body composition and increases in interleukin (IL) 6 that occur as a result of hypogonadism. Male guinea pigs (n = 40, 70- to 72-week retired breeders) were block randomized by weight into 4 groups: (1) sham surgery (SHAM)/control (CTRL) diet, (2) SHAM/conjugated linoleic acid (CLA) diet (1%), (3) orchidectomy (ORX)/CTRL diet, and (4) ORX/CLA diet. Dual-energy x-ray absorptiometry scans were performed at baseline and week 16 to assess body composition. Serum IL-6 was analyzed using an enzyme-linked immune sorbent assay. Fatty acids (FAs) from visceral and subcutaneous adipose tissue were analyzed using gas chromatography. In ORX/CTRL guinea pigs, percent total body fat increased by 6.1%, and percent lean mass decreased by 6.7% over the 16-week treatment period, whereas no changes were observed for either parameter in ORX/CLA guinea pigs. Guinea pigs fed the CLA diet gained less percent total, upper, and lower body fat than those fed the CTRL diet regardless of surgical treatment. Regional adipose tissue FA composition was reflective of dietary FAs. Serum IL-6 concentrations were not different among groups. In this study, we observed that, in male guinea pigs, hypogonadism resulted in increased fat mass and decreased lean mass. In addition, CLA was effective in reducing gains in body fat and maintaining lean mass in both hypogonadal and intact guinea pigs.

Conjugated Linoleic Triacylglycerols Exhibit Superior Lymphatic Absorption Than Free Conjugate Linoleic Acids and Have Antiobesity Properties

This study aimed to compare lymphatic absorption of conjugated linoleic acids (CLAs) in the triacylglycerol (TAG) or free fatty acid (FFA) form and to examine the antiobesity effects of different doses of CLAs in the TAG form in animals. Conjugated linoleic TAGs (containing 70.3 wt% CLAs; CLA-TAG) were prepared through lipase-catalyzed esterification of glycerol with commercial CLA mixtures (CLA-FFA). Lymphatic absorption of CLA-TAG and CLA-FFA was compared in a rat model of lymphatic cannulation. Greater amounts of cis-9,trans-11 and trans-10,cis-12 CLAs were detected in the collected lymph from a lipid emulsion containing CLA-TAG. This result suggests that CLA-TAG has greater capacity for lymphatic absorption than does CLA-FFA. The antiobesity efficacy of CLA-TAG at different doses was examined in mice with diet-induced obesity. A high-fat diet (HFD) for 12 weeks caused a significant increase in body weight and epididymal and retroperitoneal fat weights, which were significantly decreased by 2% dietary supplementation (w/w) with CLA-TAG. CLA-TAG at 2% significantly attenuated the HFD-induced upregulation of serum TAG, but led to hepatomegaly and exacerbated HFD-induced hypercholesterolemia. CLA-TAG at 1% significantly attenuated upregulation of retroperitoneal fat weight and significantly increased liver weight, which was decreased by the HFD. Nonetheless, the liver weight in group "HFD +1% CLA-TAG" was not significantly different from that of normal diet controls. CLA-TAG at 1% significantly reduced serum TAG levels and did not exacerbate HFD-induced hypercholesterolemia. Thus, 1% dietary supplementation with CLA-TAG reduces retroperitoneal fat weight without apparent hepatomegaly, a known side-effect of CLAs in mouse models of obesity.

The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility

In female mammals, mechanisms have been developed, throughout evolution, to integrate environmental, nutritional and hormonal cues in order to guarantee reproduction in favorable energetic conditions and to inhibit it in case of food scarcity. This metabolic strategy could be an advantage in nutritionally poor environments, but nowadays is affecting women's health. The unlimited availability of nutrients, in association with reduced energy expenditure, leads to alterations in many metabolic pathways and to impairments in the finely tuned inter-relation between energy metabolism and reproduction, thereby affecting female fertility. Many energetic states could influence female reproductive health being under- and over-weight, obesity and strenuous physical activity are all conditions that alter the profiles of specific hormones, such as insulin and adipokines, thus impairing women fertility. Furthermore, specific classes of nutrients might affect female fertility by acting on particular signaling pathways. Dietary fatty acids, carbohydrates, proteins and food-associated components (such as endocrine disruptors) have per se physiological activities and their unbalanced intake, both in quantitative and qualitative terms, might impair metabolic homeostasis and fertility in premenopausal women. Even though we are far from identifying a "fertility diet", lifestyle and dietary interventions might represent a promising and invaluable strategy to manage infertility in premenopausal women.

Maternal supplementation with conjugated linoleic acid in the setting of diet-induced obesity normalises the inflammatory phenotype in mothers and reverses metabolic dysfunction and impaired insulin sensitivity in offspring

Maternal consumption of a high-fat diet significantly impacts the fetal environment and predisposes offspring to obesity and metabolic dysfunction during adulthood. We examined the effects of a high-fat diet during pregnancy and lactation on metabolic and inflammatory profiles and whether maternal supplementation with the anti-inflammatory lipid conjugated linoleic acid (CLA) could have beneficial effects on mothers and offspring. Sprague-Dawley rats were fed a control (CD; 10% kcal from fat), CLA (CLA; 10% kcal from fat, 1% total fat as CLA), high-fat (HF; 45% kcal from fat) or high fat with CLA (HFCLA; 45% kcal from fat, 1% total fat as CLA) diet ad libitum 10days prior to and throughout gestation and lactation. Dams and offspring were culled at either late gestation (fetal day 20, F20) or early postweaning (postnatal day 24, P24). CLA, HF and HFCLA dams were heavier than CD throughout gestation. Plasma concentrations of proinflammatory cytokines interleukin-1β and tumour necrosis factor-α were elevated in HF dams, with restoration in HFCLA dams. Male and female fetuses from HF dams were smaller at F20 but displayed catch-up growth and impaired insulin sensitivity at P24, which was reversed in HFCLA offspring. HFCLA dams at P24 were protected from impaired insulin sensitivity as compared to HF dams. Maternal CLA supplementation normalised inflammation associated with consumption of a high-fat diet and reversed associated programming of metabolic dysfunction in offspring. This demonstrates that there are critical windows of developmental plasticity in which the effects of an adverse early-life environment can be reversed by maternal dietary interventions.

Endogenous LPS alters liver GH/IGF system gene expression and plasma lipoprotein lipase in goats

Endotoxin lipopolysaccharide (LPS) affects the ruminant health and animal performance. The main purposes of this study were to investigate the potential effects of GH/IGF system and lipoprotein lipase (LPL) concentration on resistance the circulating LPS concentration increased in liver with high concentrate diet treatment. Non-lactating goats were randomly allocated to two groups: a high-concentrate diet (HCD) or a low-concentrate diet (LCD) in cross over design and the blood collection at different time points after feeding at the end of the experiment. The average rumen pH was significantly reduced (P<0.05), but the duration with pH was not more than 120 min in the HCD group. The plasma LPL concentration was significantly raised (P<0.05). However, from 2 h onwards, LPS concentration was significantly reduced (P<0.01) in the HCD group compared with LCD group. In addition, the plasma IGF1 concentration and the hepatic insulin-like growth factor-1 receptor (IGF1R) mRNA expression were markedly reduced (P<0.05). However, growth hormone (GH) secretion at 15, 30, and 45 min after feeding and growth hormone receptor (GHR) mRNA expression in the liver was significantly increased (P<0.05) in HCD group. The correlation analysis showed that the plasma LPL concentration was positively correlated with hepatic GHR mRNA expression (P<0.05). Conversely, the plasma LPS concentration was negatively correlated with LPL concentration (P<0.05). These findings reveal that alterations in GH/IGF system function in response to a high-concentrate diet are accompanied by corresponding changes in systemic LPL in non-lactating goats' liver in presence of endogenous LPS stress.

Low level of trans-10, cis-12 conjugated linoleic acid decreases adiposity and increases browning independent of inflammatory signaling in overweight Sv129 mice

The objective of this study was to determine the extent to which a low level of trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) decreases adiposity and increases browning in overweight mice, its dependence on inflammatory signaling and potential synergistic effects of daily exercise. Young, Sv129 male mice were fed a high-fat diet for 5 weeks to make them fat and glucose intolerant and then switch them to a low-fat diet with or without 0.1% 10,12 CLA, sodium salicylate or exercise for another 7 weeks. 10,12 CLA decreased white adipose tissue (WAT) and brown adipose tissue mass, and increased the messenger RNA and protein levels, and activities of enzymes associated with thermogenesis or fatty acid oxidation in WAT. Mice fed 10,12 CLA had lower body temperatures compared to controls during cold exposure, which coincided with decreased adiposity. Although sodium salicylate decreased 10,12 CLA-mediated increases in markers of inflammation in WAT, it did not affect other outcomes. Exercise had no further effect on the outcomes measured. Collectively, these data indicate that 10,12 CLA-mediated reduction of adiposity is independent of inflammatory signaling, and possibly due to up-regulation of fatty acid oxidation and heat production in order to regulate body temperature. Although this low level of 10,12 CLA reduced adiposity in overweight mice, hepatomegaly and inflammation are major health concerns.

Modulation of peroxisome proliferator-activated receptor gamma (PPAR γ) by conjugated fatty acid in obesity and inflammatory bowel disease

Conjugated fatty acids including conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA) have drawn significant attention for their variety of biologically beneficial effects. Evidence suggested that CLA and CLNA could play physiological roles by regulating the expression and activity of PPAR γ. This review summarizes the current understanding of evidence of the role of CLA (cis-9,trans-11 CLA and trans-10,cis-12 CLA) and CLNA (punicic acid and α-eleostearic acid) in modulating the expression or activity of PPAR γ that could in turn be employed as complementary treatment for obesity and inflammatory bowel disease.

Butter naturally enriched in cis-9, trans-11 CLA prevents hyperinsulinemia and increases both serum HDL cholesterol and triacylglycerol levels in rats

BACKGROUND

Evidence from in vitro and animal studies indicates that conjugated linoleic acid (CLA) possesses anti-diabetic properties, which appear to be attributed to cis-9, trans-11 CLA, the major CLA isomer in ruminant fat. However, there is a shortage of studies addressing CLA from natural source. The present study aimed to evaluate the effects of butter naturally enriched in cis-9, trans-11 CLA on parameters related to glucose tolerance, insulin sensitivity and dyslipidemia in rats.

METHODS

Forty male Wistar rats were randomly assigned to the following dietary treatments (n=10/group), for 60 days: 1) Normal fat-Soybean oil (NF-So): diet containing 4.0% soybean oil (SO); 2) High Fat-Control Butter (HF-Cb): diet containing 21.7% control butter and 2.3% SO; 3) High Fat-CLA enriched Butter (HF-CLAb): diet containing 21.7% cis-9, trans-11 CLA-enriched butter and 2.3% SO; and 4) High fat-Soybean oil (HF-So): diet containing 24.0% SO. HF-Cb and HF-CLAb diets contained 0.075% and 0.235% of cis-9, trans-11 CLA, respectively.

RESULTS

HF-CLAb-fed rats had lower serum insulin levels at fasting than those fed with the HF-Cb diet, while the PPARγ protein levels in adipose tissue was increased in HF-CLAb-fed rats compared to HF-Cb-fed rats. Furthermore, R-QUICK was lower in HF-Cb than in NF-So group, while no differences in R-QUICK were observed among NF-So, HF-CLAb and HF-So groups. Serum HDL cholesterol levels were higher in HF-CLAb-fed rats than in those fed NF-So, HF-Cb and HF-So diets, as well as higher in NF-So-fed rats than in HF-Cb and HF-So-fed rats. HF-CLAb, HF-Cb and HF-So diets reduced serum LDL cholesterol levels when compared to NF-So, whereas serum triacylglycerol levels were increased in HF-CLAb.

CONCLUSION

Feeding rats on a high-fat diet containing butter naturally enriched in cis-9, trans-11 CLA prevented hyperinsulinemia and increased HDL cholesterol, which could be associated with higher levels of cis-9, trans-11 CLA, vaccenic acid, oleic acid and lower levels of short and medium-chain saturated fatty acids from butter naturally modified compared to control butter. On the other hand CLA-enriched butter also increased serum triacylglycerol levels, which could be associated with concomitant increases in the content of trans-9 and trans-10 C18:1 isomers in the CLA-enriched butter.

Dietary Conjugated Linoleic Acid Supplementation Leads to Downregulation of PPAR Transcription in Broiler Chickens and Reduction of Adipocyte Cellularity

Conjugated linoleic acids (CLA) act as an important ligand for nuclear receptors in adipogenesis and fat deposition in mammals and avian species. This study aimed to determine whether similar effects are plausible on avian abdominal fat adipocyte size, as well as abdominal adipogenic transcriptional level. CLA was supplemented at different levels, namely, (i) basal diet without CLA (5% palm oil) (CON), (ii) basal diet with 2.5% CLA and 2.5% palm oil (LCLA), and (iii) basal diet with 5% CLA (HCLA).The content of cis-9, trans-11 CLA was between 1.69- and 2.3-fold greater (P < 0.05) than that of trans-10, cis-12 CLA in the abdominal fat of the LCLA and HCLA group. The adipogenic capacity of the abdominal fat depot in LCLA and HCLA fed chicken is associated with a decreased proportion of adipose cells and monounsaturated fatty acids (MUFA). The transcriptional level of adipocyte protein (aP2) and peroxisome proliferator-activated receptor gamma (PPARγ) was downregulated by 1.08- to 2.5-fold in CLA supplemented diets, respectively. It was speculated that feeding CLA to broiler chickens reduced adipocyte size and downregulated PPARγ and aP2 that control adipocyte cellularity. Elevation of CLA isomers into their adipose tissue provides a potential CLA-rich source for human consumption.

Intake of butter naturally enriched with cis9,trans11 conjugated linoleic acid reduces systemic inflammatory mediators in healthy young adults

A conjugated linoleic acid (CLA) depletion-repletion study was carried out to investigate the effects of dietary c9,t11 CLA on C-reactive protein, transcription factor NFκB, metalloproteinases 2 and 9, inflammatory mediators (adiponectin, TNFα, IL-2, IL-4, IL-8, IL-10), body composition, and erythrocyte membrane composition in healthy normal-weight human adults. CLA depletion was achieved through an 8-week period of restricted dairy fat intake (depletion phase; CLA intake was 5.2±5.8 mg/day), followed by an 8-week period in which individuals consumed 20 g/day of butter naturally enriched with c9,t11 CLA (repletion phase; CLA intake of 1020±167 mg/day). The participants were 29 healthy adult volunteers (19 women and 10 men, aged 22 to 36 years), with body mass index between 18.0 and 29.9 kg m(-2). Blood samples were collected at baseline and at the end of both depletion and repletion phases. The content of CLA in erythrocytes decreased during CLA-depletion and increased during CLA-repletion. Intake of CLA-enriched butter increased the serum levels of anti-inflammatory IL-10 but reduced transcription factor NFκB in blood and serum levels of TNFα, IL-2, IL-8 and inactive metalloproteinase-9. Moreover, reduced activity of metalloproteinases 2 and 9 in serum was observed during the CLA-repletion period. In contrast, intake of CLA-enriched butter had no effects on body composition (DXA analysis) as well as on serum levels of adiponectin, C-reactive protein, and IL-4. Taken together, our results indicate that the intake of a c9,t11 CLA-enriched butter by normal-weight subjects induces beneficial changes in immune modulators associated with sub-clinical inflammation in overweight individuals.

trans-10,cis-12 CLA promotes osteoblastogenesis via SMAD mediated mechanism in bone marrow mesenchymal stem cells

The inverse relationship between osteoblast and adipocyte differentiation in bone marrow mesenchymal stem cells has been linked to overall bone mass. It has previously been reported that conjugated linoleic acid (CLA) inhibits adipogenesis via a peroxisome-proliferator activated receptor-γ (PPARγ) mediated mechanism, while it increases osteoblastogenesis via a PPARγ-independent mechanism in mesenchymal stem cells. This suggests potential implication of CLA on improving bone mass. Thus the purpose of this study was to determine involvement of CLA on regulation of osteoblastogenesis in murine mesenchymal stem cells by focusing on the Mothers against decapentaplegic (MAD)-related family of molecules 8 (SMAD8), one of key regulators of osteoblastogenesis. The trans-10,cis-12 CLA, but not the cis-9,trans-11, significantly increased osteoblastogenesis via SMAD8, and inhibited adipogenesis independent of SMAD8, while inhibiting factors regulating osteoclastogenesis in this model. These suggest that CLA may help improve osteoblastogenesis via a SMAD8 mediated mechanism.

A rumen unprotected conjugated linoleic acid supplement inhibits milk fat synthesis and improves energy balance in lactating goats

Feeding trans-10, cis-12 CLA supplements in a rumen-protected form has been shown to cause milk fat depression (MFD) in cows, ewes, and goats. Methyl esters of CLA were shown to be as effective as FFA in inducing MFD when infused postruminally, but their efficacy as a feed supplement has not been addressed in studies with lactating ruminants. In the present study, we investigated the effects of an unprotected trans-10, cis-12 CLA supplement as methyl esters on performance, milk composition, and energy status of dairy goats. Eighteen multiparous Toggenburg goats were randomly assigned to dietary treatments in a crossover experimental design (14 d treatment periods separated by a 7 d washout interval): 30 g/d of calcium salts of fatty acids (Control) or 30 g/d of a rumen unprotected CLA supplement containing 29.9% of trans-10, cis-12 CLA as methyl esters (CLA). Lipid supplements were mixed into a concentrate and fed individually to animals 3 times a day as a total mixed ration component. The DMI, milk yield, milk protein and lactose content and secretion, and somatic cell count were unaffected by CLA treatment. On the other hand, milk fat content and yield were reduced by 19.9 and 17.9% in CLA-fed goats. Reduced milk fat yield in CLA-fed goats was a consequence of a lower secretion of both preformed and de novo synthesized fatty acids. The CLA treatment also changed the milk fatty acid profile, which included a reduction in the concentration of SFA (2.5%), increased MUFA and PUFA (5.6 and 5.4%, respectively), and a pronounced increase (1576%) in milk fat trans-10, cis-12 CLA. Consistent with the high milk fat trans-10, cis-12 CLA content, all desaturase indexes were reduced in milk fat from CLA-fed goats. The MFD induced by CLA reduced the energy required for milk production by 22%, which was accompanied by an improvement in the estimated energy balance (P < 0.001), greater blood glucose concentration (P < 0.05), and a trend for increased BW (P = 0.08). Approximately 7.2% of trans-10, cis-12 CLA was estimated to escape from rumen biohydrogenation and indirect comparisons with data obtained from other studies suggest equivalent MFD between dietary CLA in the methyl ester form and rumen protected sources. Thus, despite the apparent low degree of rumen protection, our results suggest that methyl esters of CLA could be an alternative to rumen protected CLA supplements due to manufacturing and cost advantages.

Conjugated linoleic acids alter body composition differently according to physiological age in Moulard ducks

Conjugated linoleic acids (CLA) have been shown to have remarkable yet inconsistent metabolic effects in mice, rats, hamsters, chickens, cattle, and humans. In particular, effects on lipogenesis vary with tissue, physiological state, and species. In this study we tested the hypothesis that CLA would differentially affect ducks of the same genetic background but of differing age. Growing (7 wk) and maintenance (11 wk) Moulard ducks were grouped by age and fed a standard diet supplemented with 5% soybean oil (control) or 5% CLA isomer mixture. Birds were slaughtered after 3 or 6 wk for assessment of body composition including adipose, liver, viscera, and empty carcass weight. Serum nonesterified fatty acid (NEFA) and glucose concentrations were evaluated, and gene targets were cloned from the duck to use in quantifying mRNA abundance for genes involved in lipogenesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and lipid oxidation (carnitine palmitoyl transferase-1, CPT-1) in liver tissue from maintenance birds. After 3 wk, the growing CLA group exhibited a 24% decrease in dissectible adipose tissue (P < 0.05), whereas maintenance birds showed no significant diet effect. After 6 wk, the growing CLA group exhibited a 20% increase in liver mass compared with the control (P < 0.05), but no diet effect on adipose tissue. Maintenance birds receiving dietary CLA had a 42% decrease in adipose tissue mass after 6 wk; increased serum NEFA, ACC, and CPT-1 mRNA after 3 and 6 wk (P < 0.05); and increased FAS mRNA after 3 wk of treatment (P < 0.05). These data indicate that CLA have potent effects on lipid metabolism in ducks, but these effects differ depending on physiological age.

Conjugated linoleic acid and calcium co-supplementation improves bone health in ovariectomised mice

Osteoporosis is a significant health concern for the elderly; conjugated linoleic acid (CLA) has been shown to improve overall bone mass when calcium is included as a co-supplement. However, potential effects of CLA and calcium on bone mass during a period of bone loss have not been reported. The purpose of this study was to determine how dietary calcium modulates the effects of conjugated linoleic acid (CLA) in preventing bone loss, using an ovariectomised mouse model. CLA supplementation significantly prevented ovariectomy-associated weight and fat mass gain, compared to non-supplemented controls. CLA significantly increased bone markers without major changes in bone mineral composition in the femur compared to respective controls. CLA treatment increased serum parathyroid hormone (PTH) significantly (p=0.0172), while serum 1,25-dihydroxyvitamin D3 concentration was not changed by CLA. Meanwhile, CLA significantly reduced femur tartrate resistant acid phosphatase (TRAP) activity, suggesting potential reduction of osteoclastogenesis. The data suggest that CLA, along with dietary calcium, has great potential to be used to prevent bone loss and weight gain associated with menopause.

10E,12Z-conjugated linoleic acid impairs adipocyte triglyceride storage by enhancing fatty acid oxidation, lipolysis, and mitochondrial reactive oxygen species

Conjugated linoleic acid (CLA) is a naturally occurring dietary trans fatty acid found in food from ruminant sources. One specific CLA isomer, 10E,12Z-CLA, has been associated with health benefits, such as reduced adiposity, while simultaneously promoting deleterious effects, such as systemic inflammation, insulin resistance, and dyslipidemia. The precise mechanisms by which 10E,12Z-CLA exerts these effects remain unknown. Despite potential health consequences, CLA continues to be advertised as a natural weight loss supplement, warranting further studies on its effects on lipid metabolism. We hypothesized that 10E,12Z-CLA impairs lipid storage in adipose tissue by altering the lipid metabolism of white adipocytes. We demonstrate that 10E,12Z-CLA reduced triglyceride storage due to enhanced fatty acid oxidation and lipolysis, coupled with diminished glucose uptake and utilization in cultured adipocytes. This switch to lipid utilization was accompanied by a potent proinflammatory response, including the generation of cytokines, monocyte chemotactic factors, and mitochondrial superoxide. Disrupting fatty acid oxidation restored glucose utilization and attenuated the inflammatory response to 10E,12Z-CLA, suggesting that fatty acid oxidation is critical in promoting this phenotype. With further investigation into the biochemical pathways involved in adipocyte responses to 10E,12Z-CLA, we can discern more information about its safety and efficacy in promoting weight loss.