Dietary restriction reduces blood lipids and ameliorates liver function of mice with hyperlipidemia

A highly sensitive optical fiber sensor enables rapid triglycerides-specific detection and measurement at different temperatures using convolutional neural networks

For specific recognition and sensitive detection of triglycerides (TGs), an optical fiber sensor (OFS) based on an enhanced core diameter mismatch was proposed. The sensitivity of the sensor is significantly increased due to the repetitive excitation of the higher-order cladding modes. A technique for immobilizing lipase using covalent binding technology was presented and demonstrated by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy. The interference dip of the sensor was shifted due to TGs being hydrolyzed in the presence of lipase. The sensor shows an optimal response within 3 min and exhibits a high sensitivity of 0.9933 nm/(mg/ml) and a limit of detection of 0.0822 mg/ml in the concentration range 0-8 mg/ml at a temperature of 37 °C and a pH of 7.4. The response of the sensor to TGs concentration at different temperatures and pH was investigated. The reproducibility, reusability, and stability of the proposed sensor were tested and verified experimentally. The biosensor is highly specific for TGs and unaffected by many other interfering substances. Further, the measurement of TGs concentration at different temperatures was realized. This method provides a new way to detect TGs rapidly and reliably and has potential applications in medical research and clinical diagnosis.

Role of Autophagy and Apoptosis in Aluminum Exposure-Induced Liver Injury in Rats

Aluminum (Al) exposure can lead to different degrees of damage to various organ systems of the body. It has been previously revealed that Al exposure can damage the liver, causing liver dysfunction. However, the specific mechanism remains unclear. This research aims to uncover the damaging effect of Al exposure on rat liver and to demonstrate the role of autophagy and apoptosis in this effect. Thirty-two Wistar rats were randomly divided into the control group (C group), low-dose Al exposure group (L group), middle-dose Al exposure group (M group), and high-dose Al exposure group (H group) (n = 8). The rats, respectively, received intraperitoneal injections of 0, 5, 10, and 20 mg/kg·day AlCl₃ solution for 4 weeks (5 times/week). After the experiment, changes in the ultrastructure and autolysosome in rat liver were observed; the liver function, apoptosis rate, as well as levels of apoptosis-associated proteins and autophagy-associated proteins were detected. The results indicated that Al exposure damaged rat liver function and structure and resulted in an increase in autolysosomes. TUNEL staining revealed an elevated number of apoptotic hepatocytes after Al exposure. Moreover, we found from Western blotting that the levels of autophagy-associated proteins Beclin1 and LC3-II were increased; apoptotic protein Caspase-3 level was elevated and the Bcl-2/Bax ratio was reduced. Our research suggested that Al exposure can lead to high autophagy and apoptosis levels of rat hepatocytes, accompanied by hepatocyte injury and impaired liver function. This study shows that autophagy and apoptosis pathways participate in Al toxication-induced hepatocyte injury.

Protective effect of quercetin against phthalates induced hepatotoxicity in rats

Humans are increasingly exposed to ubiquitous phthalates (PEs), e.g. butyl benzyl phthalate (BBP), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP), which are widely used plasticizers in polymer products. This study was aimed to investigate the effect of phytochemical quercetin (Que) on hepatotoxicity caused by the mixture of the 3 commonly used PEs (MPEs), and further to explore the underlying mechanism. Forty male Sprague-Dawley rats were randomly divided into control group, MPEs group, and MPEs combined Que at Low-, Median-, and High-dose groups; rats in MPEs group were orally administered with 900 mg/kg/d MPEs, whereas rats in MPEs combined Que groups were simultaneously treated with 900 mg/kg/d MPEs and respectively 10, 30, and 90 mg/kg/d Que. The intervention last 30 days. Compared with control group, serum ALT, AST, LDH and AKP, and hepatic MDA, SOD, CAT and GPx were significantly increased, whereas, serum albumin and total protein were significantly decreased in MPEs group (P < 0.05); hepatic histopathological observation showed numerous inflammatory cells infiltration, hepatocyte ballooning degeneration, and numerous residual erythrocytes in the central vein in MPEs group. Western-blot analysis showed that hepatic Keap1 was downregulated, whereas Nrf2 and HO-1 were upregulated in MPEs group (P < 0.05). However, the alterations of these parameters were alleviated in MPEs combined Que at Median- and High-dose groups. The results indicated that MPEs-induced hepatic oxidative stress, and caused hepatic injuries; whereas, Que inhibited MPEs' hepatotoxicity, which might relate to Que's ability of quenching free radicals directly, and restored the regulation of Nrf2 signaling pathway.

Dual-fiber optic bioprobe system for triglyceride detection using surface plasmon resonance sensing and lipase-immobilized magnetic bead hydrolysis

The rapid and accurate detection of triglyceride (TG) plays a valuable role in the prevention and control of dyslipidemia. In this paper, a novel method for TG detection using a dual-fiber optic bioprobe system, which can accurately detect different levels of TG concentration in serum, is proposed. The system employs disposable microprobe-type fiber optic surface plasmon resonance (SPR) biosensors for signal acquisition, providing high stability and portability while avoiding cross-contamination caused by repeated use. The proposed biosensor with a high sensitivity of 1.25 nm/(mg/mL) for TG detection in serum and a tiny diameter of 125 μm, was fabricated using a novel multimode fiber-single-mode fiber-reflector (MSR) structure, which has been scarcely ever reported to the best of our knowledge. In the process of TG detection, lipase-immobilized magnetic beads were introduced to specifically hydrolyze TG, and the relationship between the TG content and the SPR differential signal was obtained from dual-fiber optic bioprobe measurements of the TG sample before and after hydrolysis. The proposed method achieved TG detection in the concentration range of 0-8 mg/mL (including healthy and unhealthy levels of TG concentration in the human body). Additionally, the miniaturized fiber optic biosensors used in this work have the advantages of low sample consumption, high sensitivity, simple operation, label-free measurement, high selectivity, and low cost. This method provides a new pathway for rapid and reliable TG detection and has potential applications in medical research and clinical diagnosis.

Oral administration of recombinant Bacillus subtilis spores expressing mutant staphylococcal enterotoxin B provides potent protection against lethal enterotoxin challenge

Pathogenicity of Staphylococcus aureus is induced by staphylococcal enterotoxin B (SEB). A mutant form of SEB (mSEB) is immunogenic as well as less toxic. Recombinant mSEB and SEB were expressed in pET28a prokaryotic plasmids. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels in mSEB-stimulated macrophages were lower than those in SEB-stimulated macrophages (p < 0.001, p < 0.01 respectively). Using CotC as a fusion protein, we constructed recombinant Bacillus subtilis spores expressing mSEB on the spore surface and evaluated their safety and protective efficacy via mouse models. Oral administration of mSEB-expressing spores increased SEB-specific IgA in feces and SEB-specific IgG1 and IgG2a in the sera, compared with mice in naïve and CotC spore-treated groups (p < 0.001, p < 0.01, p < 0.001 respectively). Six weeks following oral dosing of recombinant spores, significant differences were not found in the serum biochemical indices between the mSEB group and the naïve and CotC groups. Furthermore, oral administration of mSEB spores increased the survival rate by 33.3% in mice intraperitoneally injected with 5 µg of wild-type SEB plus 25 µg lipopolysaccharide (LPS). In summation, recombinant spores stably expressing mSEB were developed, and oral administration of such recombinant spores induced a humoral immune response and provided protection against SEB challenge in mice.

The metabolic change in serum lysoglycerophospholipids intervened by triterpenoid saponins from Kuding tea on hyperlipidemic mice

Triterpenoid saponins from Kuding tea have demonstrated preventive effects on hyperlipidaemia induced by a high-fat diet. Lysoglycerophospholipids (Lyso-GPLs) are known to be associated with proatherogenic conditions such as hyperlipidaemia. In this study, a target profiling strategy based on a multiple reaction monitoring mode was applied for the analysis of Lyso-GPLs. The metabolic changes were evaluated by the qualitative and relative quantitative distribution of six classes of Lyso-GPLs in mouse serum. A total of 153 Lyso-GPL regioisomers, consisting of 85 lysophosphatidylcholines, 15 lysophosphatidic acids, 23 lysophosphatidylethanolamines, 5 lysophosphatidylserines, 19 lysophosphatidylinositols and 6 lysophosphatidylglycerols, were detected and quantified. The results showed decreased trends in the content of total Lyso-GPLs in the serum of hyperlipidemic mice compared with that in normal controls. The content of total Lyso-GPLs significantly increased after treatment with triterpenoid saponins from Kuding tea. Among them, the proportions of most Lyso-GPLs with a higher degree of unsaturation or a longer carbon chain in fatty acyl chains dramatically decreased in hyperlipidemic mice. However, this tendency reversed after the treatment of triterpenoid saponins from Kuding tea. This is the first study regarding a target profiling strategy for the quantitative analysis of six different types of Lyso-GPLs on high-fat diet-induced hyperlipidemic mice intervened by Kuding tea. Those Lyso-GPLs changed significantly may be potential biomarkers for hyperlipidaemia, and involved in the mechanism of the preventive intervention of Kuding tea on Lipid metabolic diseases.

PPAR-γ: Its ligand and its regulation by microRNAs

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptor superfamily. PPARs are categorized into three subtypes, PPARα, β/δ, and γ, encoded by different genes, expressed in diverse tissues and participate in various biological functions and can be activated by their metabolic derivatives in the body or dietary fatty acids. The PPAR-γ also takes parts in the regulation of energy balance, lipoprotein metabolism, insulin sensitivity, oxidative stress, and inflammatory signaling. It has been implicated in the pathology of numerous diseases including obesity, diabetes, atherosclerosis, and cancers. Among various cellular and molecular targets that are able to regulate PPAR-γ and its underlying pathways, microRNAs (miRNAs) appeared as important regulators. Given that the deregulation of these molecules via targeting PPAR-γ could affect initiation and progression of various diseases, identification of miRNAs that affects PPAR-γ could contribute to the better understanding of roles of PPAR-γ in various biological and pathological conditions. Here, we have summarized the function and various ligands of PPAR-γ and have highlighted various miRNAs involved in the regulation of PPAR-γ.

Hypolipidemic effect and protection ability of liver-kidney functions of melanin from Lachnum YM226 in high-fat diet fed mice

In the present study, we investigated the hypolipidemic properties of melanin from Lachnum YM226 (LM) in high-fat diet induced hyperlipidemic mice. After the hyperlipidemic model was established, mice were randomly divided into six groups, as follows: normal control group (NC), hyperlipidemic control group (HC), positive control group (7 mg kg^-1 d^-1 simvastatin) (PC) and LM groups (50, 100 and 200 mg kg^-1 d^-1 denoted as LM-50, LM-100 and LM-200, respectively). Subsequently, the body weight, organ indices, lipid metabolism, antioxidant properties and liver-kidney functions of the mice were examined. Moreover, the activities of lipoprotein metabolism enzymes in serum and liver tissue were examined to study the feasible mechanism. The results imply that LM could effectively reduce body weight, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and atherogenic index (AI), and increase high density lipoprotein cholesterol (HDL-C). Moreover, treatment with LM also increased the antioxidant enzymes activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) and reduced malondialdehyde (MDA) content relative to the HC group. In addition, the liver and kidney damage indices such as alanine aminotransferase (ALT), aspartate aminotransaminase (AST), alkaline phosphatase (ALP), creatinine (CRE), blood urea nitrogen (BUN) and uric acid were lowered. LM administration also significantly corrected disturbances of liver-kidney functions with no fatty deposits in the liver, resulting in a protective effect against renal histological alteration. The hypolipidemic effect occurred partly due to the regulation of hepatic lipase (HL) and lipoprotein lipase (LPL) in serum and liver to markedly decrease TG. This confirms the important role of LM in the prevention of hyperlipidemia.

Effects of Chimonanthus nitens Oliv. Leaf Extract on Glycolipid Metabolism and Antioxidant Capacity in Diabetic Model Mice

The paper investigated the antihyperglycemic and antihyperlipidemic efficacy and antioxidant capacity of Chimonanthus nitens Oliv. leaf extract (COE) in combination of high-glucose-fat diet-fed and streptozotocin-induced diabetic model mice. Various physiological indexes in diabetic model mice were well improved especially by oral administration of high dose of COE; the results were listed as follows. Fast blood glucose (FBG) level and serum triglyceride (TC), total cholesterol (TG), low-density lipoprotein cholesterol (LDLC), and malondialdehyde (MDA) as well as MDA in liver were significantly reduced; fasting serum insulin (FINS) and insulin sensitivity index (ISI) were both increased; high-density lipoprotein cholesterol (HDLC) in serum was significantly increased; total antioxidant capacity (T-AOC), activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in serum and liver were apparently enhanced; liver coefficient (LC), liver transaminase, and alkaline phosphatase (ALP) were decreased. Furthermore, pancreas islets and liver in diabetic model mice showed some extend of improvement in morphology and function after 4 weeks of COE treatment. In consequence, COE was advantageous to regulate glycolipid metabolism and elevate antioxidant capacity in diabetic model mice. Thus, the present study will provide a scientific evidence for the use of COE in the management of diabetes and its related complications.

MDG-1, a Potential Regulator of PPARα and PPARγ, Ameliorates Dyslipidemia in Mice

Hyperlipidemia is a serious epidemic disease caused by lipid metabolism disorder, which is harmful to human health. MDG-1, a β-d-fructan polysaccharide extracted from Ophiopogon japonicus, has been shown to improve abnormal blood lipid levels and alleviate diabetes. However, the underlying mechanism on hyperlipidemia is largely unknown. In this study, male C57BL/6 mice were randomly separated into three groups, respectively: low-fat diet (Con), high-fat diet (HFD), and high-fat diet plus 5‰ MDG-1 (HFD + MDG-1). Body weight was measured and the serum lipid levels were analyzed. Using gene microarray, various core pathways, together with levels of gene expression within hepatocytes, were analyzed. RT-PCR was used to confirm the identity of the differentially expressed genes. MDG-1 could prevent obesity in HFD-induced mice and improve abnormal serum lipids. Besides, MDG-1 could regulate hyperlipidemia symptoms, specifically, and decrease fasting blood glucose, improve glucose tolerance, and ameliorate insulin resistance. According to results from gene microarray, most of the identified pathways were involved in the digestion and absorption of fat, biosynthesis, and catabolism of fatty acids as well as the secretion and biological synthesis of bile acids. Furthermore, MDG-1 may act upon peroxisome proliferator-activated receptors (PPAR) α and γ, activating PPARα whilst inhibiting PPARγ, thus having a potent hypolipidemic effect.

Effects of Chimonanthus nitens Oliv. Leaf Extract on Glycolipid Metabolism and Antioxidant Capacity in Diabetic Model Mice

The paper investigated the antihyperglycemic and antihyperlipidemic efficacy and antioxidant capacity of Chimonanthus nitens Oliv. leaf extract (COE) in combination of high-glucose-fat diet-fed and streptozotocin-induced diabetic model mice. Various physiological indexes in diabetic model mice were well improved especially by oral administration of high dose of COE; the results were listed as follows. Fast blood glucose (FBG) level and serum triglyceride (TC), total cholesterol (TG), low-density lipoprotein cholesterol (LDLC), and malondialdehyde (MDA) as well as MDA in liver were significantly reduced; fasting serum insulin (FINS) and insulin sensitivity index (ISI) were both increased; high-density lipoprotein cholesterol (HDLC) in serum was significantly increased; total antioxidant capacity (T-AOC), activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in serum and liver were apparently enhanced; liver coefficient (LC), liver transaminase, and alkaline phosphatase (ALP) were decreased. Furthermore, pancreas islets and liver in diabetic model mice showed some extend of improvement in morphology and function after 4 weeks of COE treatment. In consequence, COE was advantageous to regulate glycolipid metabolism and elevate antioxidant capacity in diabetic model mice. Thus, the present study will provide a scientific evidence for the use of COE in the management of diabetes and its related complications.