Korean Pine Nut Oil Attenuated Hepatic Triacylglycerol Accumulation in High-Fat Diet-Induced Obese Mice

Metabolomic and transcriptomic analysis of the synthesis process of unsaturated fatty acids in Korean pine seed kernels

Due to their rich unsaturated fatty acids, nuts of Korean pine are widely popular in the market. With growing public awareness about forest conservation and healthy eating, the primary focus of Korean pine forest management has gradually shifted from timber to nut production. The lack of understanding of the process of unsaturated fatty acid synthesis in Korean pine kernels and unclear identification of the critical period have hindered efforts to improve yield and genetic modification. This study, through metabolomic and transcriptomic analysis of five developmental stages of Korean pine kernels, identifies the critical period for the synthesis of unsaturated fatty acids, characterizes the gene expression spectrum, and identifies three gene co-expression modules highly correlated with unsaturated fatty acid synthesis. The findings not only provide new insights into the synthesis of oils in gymnosperm nuts but also offer valuable guidance for the cultivation and targeted improvement of high-quality Korean pine nut varieties.

Pine (Pinus koraiensis) Nut Oil Ameliorates Cholesterol Homeostasis and Inflammation via Modulating the miR-34a/122 Pathways in the Liver of Rats Fed a High-Cholesterol Diet

BACKGROUND

Pine (Pinus koraiensis) nut oil (PNO) has been reported to have various beneficial effects on hepatic triglyceride accumulation and atherosclerosis in animal models. MicroRNAs (miRs) are involved in various diseases by modulating physiological processes. However, the mechanism underlying PNO's effects on the regulation of miRs involved in hepatic cholesterol homeostasis and inflammation remains unclear.

OBJECTIVES

This study investigated the effects of PNO on the regulation of the miR-34a/122 pathways involved in cholesterol homeostasis and inflammation in the liver using a high-cholesterol diet (HCD) rat model.

METHODS

Six-wk-old male Sprague-Dawley rats were randomly divided into 3 groups (n = 8/group) and provided with 1) a cholesterol-free diet, 2) an HCD containing 1% cholesterol and 0.5% cholic acid, or 3) an HCD containing 5% PNO for 4 wk. Lipid analysis of serum and liver, histological evaluation, and analysis of gene and protein expression were performed.

RESULTS

PNO supplementation in HCD improved hepatic lipid profiles and elevated serum high-density lipoprotein cholesterol compared with the HCD group. PNO significantly upregulated hepatic gene expression levels of liver X receptor α and ATP-binding cassette transporter A1/G1, which are involved in cholesterol efflux (P < 0.05). Gene expressions of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), IL-6, IL-1β, monocyte chemoattractant protein-1, and inducible nitric oxide synthase were downregulated by PNO (P < 0.05). PNO also suppressed TNF-α and IL-6 protein levels by 22.3% and 17.3%, respectively (P < 0.05). PNO reduced hepatic nuclear factor-kappa B activity by 16.4% and decreased nitric oxide production in the liver and serum (P < 0.05). Furthermore, hepatic miR-34a and miR-122 expressions decreased by 16.4% and 15.7% by PNO, respectively (P < 0.05).

CONCLUSIONS

These results suggest that PNO may affect cholesterol homeostasis and inflammation, which are partially associated with the miR-34a/122 pathways in the liver under an HCD.

Dietary coconut oil lowered circulating fetuin-A levels and hepatic expression of fetuin-A in KK/TaJcl mice

Although coconut oil has attracted great attention as a functional food, enough supportive scientific evidence is lacking. In addition, the beneficial effects of coconut oil consumption on the prevention of metabolic disorders are controversial. Fetuin-A is a plasma glycoprotein secreted by hepatocytes and adipocytes. Circulating fetuin-A levels relate to insulin resistance due to macrophage-mediated adipose tissue inflammation. This study demonstrated that coconut oil feeding significantly downregulated the hepatic expression of fetuin-A and reduced its plasma level in KK mice-an obese diabetic model animal. The expression of monocyte chemoattractant protein-1, a potent inducer for macrophage infiltration, decreased in epididymal white adipose tissue in coconut oil-fed KK mice. The expression of CD68 and CD11c, markers of proinflammatory M1 macrophages, was significantly reduced by coconut oil feeding in epididymal white adipose tissue of KK mice. However, the mice did not exhibit improved insulin resistance. Our results may further support the potential of coconut oil as a dietary trigger that can reduce both circulating fetuin-A levels and infiltration of proinflammatory macrophages in visceral adipose tissue.

Widely Targeted Metabolomic Profiling Combined with Transcriptome Analysis Provides New Insights into Lipid Biosynthesis in Seed Kernels of Pinus koraiensis

Lipid-rich Pinus koraiensis seed kernels are highly regarded for their nutritional and health benefits. To ascertain the molecular mechanism of lipid synthesis, we conducted widely targeted metabolomic profiling together with a transcriptome analysis of the kernels in P. koraiensis cones at various developmental stages. The findings reveal that 148 different types of lipid metabolites, or 29.6% of total metabolites, are present in kernels. Among those metabolites, the concentrations of linoleic acid, palmitic acid, and α-linolenic acid were higher, and they steadily rose as the kernels developed. An additional 10 hub genes implicated in kernel lipid synthesis were discovered using weighted gene co-expression network analysis (WGCNA), gene interaction network analysis, oil body biosynthesis, and transcriptome analysis. This study used lipid metabolome and transcriptome analyses to investigate the mechanisms of key regulatory genes and lipid synthesis molecules during kernel development, which served as a solid foundation for future research on lipid metabolism and the creation of P. koraiensis kernel food.

The Beneficial Effects of Pine Nuts and Its Major Fatty Acid, Pinolenic Acid, on Inflammation and Metabolic Perturbations in Inflammatory Disorders

Inflammatory disorders such as atherosclerosis, diabetes and rheumatoid arthritis are regulated by cytokines and other inflammatory mediators. Current treatments for these conditions are associated with significant side effects and do not completely suppress inflammation. The benefits of diet, especially the role of specific components, are poorly understood. Polyunsaturated fatty acids (PUFAs) have several beneficial health effects. The majority of studies on PUFAs have been on omega-3 fatty acids. This review will focus on a less studied fatty acid, pinolenic acid (PNLA) from pine nuts, which typically constitutes up to 20% of its total fatty acids. PNLA is emerging as a dietary PUFA and a promising supplement in the prevention of inflammatory disorders or as an alternative therapy. Some studies have shown the health implications of pine nuts oil (PNO) and PNLA in weight reduction, lipid-lowering and anti-diabetic actions as well as in suppression of cell invasiveness and motility in cancer. However, few reviews have specifically focused on the biological and anti-inflammatory effects of PNLA. Furthermore, in recent bioinformatic studies on human samples, the expression of many mRNAs and microRNAs was regulated by PNLA indicating potential transcriptional and post-transcriptional regulation of inflammatory and metabolic processes. The aim of this review is to summarize, highlight, and evaluate research findings on PNO and PNLA in relation to potential anti-inflammatory benefits and beneficial metabolic changes. In this context, the focus of the review is on the potential actions of PNLA on inflammation along with modulation of lipid metabolism and oxidative stress based on data from both in vitro and in vivo experiments, and human findings, including gene expression analysis.

Dietary supplementation with Korean pine nut oil decreases body fat accumulation and dysregulation of the appetite-suppressing pathway in the hypothalamus of high-fat diet-induced obese mice

BACKGROUND/OBJECTIVES

Korean pine nut oil (PNO) has been reported to suppress appetite by increasing satiety hormone release. However, previous studies have rendered inconsistent results and there is lack of information on whether dietary Korean PNO affects the expression of satiety hormone receptors and hypothalamic neuropeptides. Therefore, our study sought to evaluate the chronic effects of Korean PNO on the long-term regulation of energy balance.

MATERIALS/METHODS

Five-week-old male C57BL/6 mice were fed with control diets containing 10% kcal fat from Korean PNO or soybean oil (SBO) (PC or SC) or high-fat diets (HFDs) containing 35% kcal fat from lard and 10% kcal fat from Korean PNO or SBO (PHFD or SHFD) for 12 weeks. The expression of gastrointestinal satiety hormone receptors, hypothalamic neuropeptides, and genes related to intestinal lipid absorption and adipose lipid metabolism was then measured.

RESULTS

There was no difference in the daily food intake between PNO- and SBO-fed mice; however, the PC and PHFD groups accumulated 30% and 18% less fat compared to SC and SHFD, respectively. Korean PNO-fed mice exhibited higher messenger RNA (mRNA) expression of Ghsr (ghrelin receptor) and Agrp (agouti-related peptide) (P < 0.05), which are expressed when energy consumption is low to induce appetite as well as the appetite-suppressing neuropeptides Pomc and Cartpt (P = 0.079 and 0.056, respectively). Korean PNO downregulated jejunal Cd36 and epididymal Lpl mRNA expressions, which could suppress intestinal fatty acid absorption and fat storage in white adipose tissue. Consistent with these findings, Korean PNO-fed mice had higher levels of fecal non-esterified fatty acid excretion. Korean PNO also tended to downregulate jejunal Apoa4 and upregulate epididymal Adrb3 mRNA levels, suggesting that PNO may decrease chylomicron synthesis and induce lipolysis.

CONCLUSIONS

In summary, Korean PNO attenuated body fat accumulation, and appeared to prevent HFD-induced dysregulation of the hypothalamic appetite-suppressing pathway.

A review of the functional effects of pine nut oil, pinolenic acid and its derivative eicosatrienoic acid and their potential health benefits

Pine nut oil (PNO) is rich in a variety of unusual delta-5-non-methylene-interrupted fatty acids (NMIFAs), including pinolenic acid (PLA; all cis-5,-9,-12 18:3) which typically comprises 14 to 19% of total fatty acids. PLA has been shown to be metabolised to eicosatrienoic acid (ETA; all cis-7,-11,-14 20:3) in various cells and tissues. Here we review the literature on PNO, PLA and its metabolite ETA in the context of human health applications. PNO and PLA have a range of favourable effects on body weight as well as fat deposition through increased energy expenditure (fatty acid oxidation) and decreased food energy intake (reduced appetite). PNO and PLA improve blood and hepatic lipids in animal models and insulin sensitivity in vitro and reduce inflammation and modulate immune function in vitro and in animal models. The few studies which have examined effects of ETA indicate it has anti-inflammatory properties. Another NMIFA from PNO, sciadonic acid (all cis-5,-11,-14 20:3), has generally similar properties to PLA where these have been investigated. There is potential for human health benefits from PNO, its constituent NMIFA PLA and the PLA derivative ETA. However further studies are needed to explore the effects in humans.

Modulation of hepatic lipidome by rhodioloside in high-fat diet fed apolipoprotein E knockout mice

BACKGROUND

Rhodioloside is a glucoside of tyrosol isolated from Rhodiola rosea. However, its regulating effect on hepatic dyslipidemia of atherogenic mice has rarely been studied.

PURPOSE

The specific aims of current study included to clarify lipidomic perturbation in liver tissues of apolipoprotein E deficient (apoE^-/-) mice fed with high-fat diet, and to examine the effects of rhodioloside against atherosclerosis and dyslipidemia.

STUDY DESIGN

The comparisons of hepatic lipidome were executed between wide type (WT) mice fed with normal diet (NDC) and apoE^-/- mice fed with high-fat diet (Model), WT mice fed with high-fat diet (HFDC) versus the model mice, as well as the model mice versus rhodioloside-treated atherosclerotic mice.

METHODS

Ultra high performance liquid chromatography coupled with a Q exactive hybrid quadrupole-orbitrap mass spectrometry (UPLC-MS/MS) was employed to provide an unbiased and simultaneous measurement of individual lipid species in liver tissues.

RESULTS

Multivariate statistical analysis derived from LC-MS spectra revealed that high-fat diet and apoE deficiency caused a series of disturbances on glyerolipid metabolism, glycerophospholipid metabolism and sphingolipid metabolism. Rhodioloside administration showed atheroprotective effects on the apoE^-/- mice with regulating the levels of 1 phosphatidylcholine, 2 phosphatidylserines, 5 alkyldiacylglycerols and 3 alkenyldiacylglycerols back to normal. In particular, PC (4:0/15:0) was positively associated with high-density lipoprotein cholesterol in blood, both of which could be ameliorated by rhodioloside.

CONCLUSION

Our results identified the abnormal hepatic lipids in atherosclerosis progression that could efficiently improved by rhodioloside. These lipids contributed to biological understanding of atherogenic dyslipidemia in liver and could also served as sensitive indicators for drug target screening.

Nonalcoholic Fatty Liver Disease Induced by High-Fat Diet in C57bl/6 Models

Researchers have a range of animal models in which to study Nonalcoholic fatty liver disease (NAFLD). Induction of NAFLD by a high-fat diet in the C57BL/6 strain is the most widely used among mice. In this study, we review works that performed NAFLD induction by a high-fat diet using the C57BL/6 strain, focusing on experiments on the effects of lipid ingestion. Studies are initially distinguished into researches in which mice received lipids by oral gavage and studies in which lipid was added to the diet, and each of these designs has peculiarities that must be considered. Oral gavage can be stressful for animals and needs trained handlers but allows accurate control of the dose administered. The addition of oils to the diet can prevent stress caused to mice by gavage, but possible changes in the consistency, taste, and smell of the diet should be considered. Regarding the experimental design, some variables, such as animal sex, treatment time, and diet-related variables, appear to have a definite pattern. However, no pattern was found regarding the number of animals per group, age at the beginning of the experiment, time of adaptation, the substance used as a vehicle, and substance used as a control.

Diet Consisting of Balanced Yogurt, Fruit, and Vegetables Modifies the Gut Microbiota and Protects Mice against Nonalcoholic Fatty Liver Disease

BACKGROUND

Calorie restriction (CR) is a therapeutically effective method for nonalcoholic fatty liver disease. However, the compliance of the CR method is relatively poor. New CR methods are needed.

METHODS AND RESULTS

Each week, mice are given a 5-day high-fat diet (HFD) ad libitum plus 2 days of an intermittent calorie restriction (ICR) diet (50% calorie restriction) consisting of yogurt, fruit, and vegetables, for 16 weeks. The effect of the ICR diet model on the fatty liver of mice is examined. Compared with continuous HFD-fed mice, the mice feeding HFD+ICR have lower body weight and hepatic steatosis, reduced serum lipid and transaminase levels, increased fatty acid oxidation gene of Cpt1a, and decreased hepatic lipid synthesis gene of Pparγ and Srebf-1c, as well as improved insulin resistance and lower level of inflammation. Moreover, ICR reverses the dysbacteriosis in HFD group, including the lower Shannon diversity indexes and lower abundance of Lactobacillus.

CONCLUSION

An ICR diet consisting of yogurt, fruit, and vegetables attenuates the development of HFD-induced hepatic steatosis in mice. Furthermore, HFD+ICR diet is associated with a different fecal microbiota that tends to be more similar to normal diet controls.

Acyl-CoA dehydrogenase long chain expression is associated with esophageal squamous cell carcinoma progression and poor prognosis

Background

Acyl-CoA dehydrogenase long chain (ACADL) was revealed to have a correlation with malignant progression of cancer. However, whether ACADL plays a role in clinical therapy remains unclear. The clinicopathological role of ACADL in esophageal squamous cell carcinoma (ESCC) will be discussed in this study.

Materials and methods

The expression of ACADL was analyzed via real-time PCR and Western blotting to assess mRNA and protein levels in ESCC cell lines and normal esophageal epithelial cells (NEECs), in six paired ESCC tumors and relative normal tissues. Furthermore, immunohistochemical staining was performed on 135 paraffin-embedded ESCC specimens to assess ACADL expression. The clinicopathological significance of ACADL expression was further investigated via survival analysis and Cox regression analysis.

Results

ACADL was found to be markedly upregulated in ESCC cell lines when compared with NEECs. Moreover, various experiments such as quantitative real-time PCR, Western blot, and immunohistochemical analyses all revealed that ACADL expression was increased in all six paired ESCC tumors and matched normal tissues. Furthermore, immunohistochemical analysis revealed an increased level of ACADL protein expression in all 135 paraffin-embedded samples from ESCC patients, which increased with disease progression.

Conclusion

We demonstrated that ACADL is overexpressed in ESCC, both in cell lines and clinical specimens. ACADL is found to be a vital regulator in ESCC progression and can predict a worse outcome for ESCC patients, suggesting that ACADL might be a valuable molecule to be targeted for clinical therapy of ESCC treatment.

Effects of mild calorie restriction on lipid metabolism and inflammation in liver and adipose tissue

Calorie restriction (CR) has been reported to improve lipid metabolism and to decrease inflammatory diseases. However, most existing CR models use 30-50% calorie reduction, which is hard to achieve in humans. We investigated the effects of mild CR on lipid metabolism and inflammatory responses. Male C57BL/6 mice were fed control diet (10% kcal fat, Control) or high fat diet (60% kcal fat, HFD) ad libitum or reduced amount of control diet to achieve 15% CR for 16 wks. Body weights, white adipose tissue weights, liver triacylglycerol levels, and serum fetuin-A levels were lower in CR than in the Control. Serum adiponectin levels were higher in CR and lower in HFD compared with the Control. Liver and adipose tissue Mcp-1 mRNA levels were significantly lower in CR compared with the Control. Adipose tissue mRNA levels of Mcp-1, Il-6, Tnf-α and Socs3 were significantly higher in HFD than in the Control and CR, and levels of these negatively correlated with serum adiponectin levels. CR group had the lowest leptin levels and the highest liver Lepr expression, and Lepr mRNA levels positively correlated with liver Socs3 mRNA levels. Our findings showed that mild CR lowered adiposity which resulted in higher adiponectin and lower fetuin-A levels, and might have contributed to alleviation of inflammatory status in the liver and adipose tissue. Furthermore, mild CR might have affected leptin sensitivity by up-regulating Lepr expression.

Pinolenic Acid in Structured Triacylglycerols Exhibits Superior Intestinal Lymphatic Absorption As Compared to Pinolenic Acid in Natural Pine Nut Oil

The positional distribution pattern of fatty acids (FAs) in the triacylglycerols (TAGs) affects intestinal absorption of these FAs. The aim of this study was to compare lymphatic absorption of pinolenic acid (PLA) present in structured pinolenic TAG (SPT) where PLA was evenly distributed on the glycerol backbone, with absorption of pine nut oil (PNO) where PLA was predominantly positioned at the sn-3 position. SPT was prepared via the nonspecific lipase-catalyzed esterification of glycerol with free FA obtained from PNO. Lymphatic absorption of PLA from PNO and from SPT was compared in a rat model of lymphatic cannulation. Significantly (P < 0.05) greater amounts of PLA were detected in lymph collected for 8 h from an emulsion containing SPT (28.5 ± 0.7% dose) than from an emulsion containing PNO (26.2 ± 0.6% dose), thereby indicating that PLA present in SPT has a greater capacity for lymphatic absorption than PLA from PNO.