Oxidative stress leads to cholesterol accumulation in vascular smooth muscle cells

A data mining approach to identify key radioresponsive genes in mouse model of radiation induced intestinal injury

Radiation-mediated GI injury (RIGI) in humans either due to accidental or intentional exposures, can only be managed with supporting care with no approved countermeasures available till now. Early detection and monitoring of RIGI is important for effective medical management and improve survival chances in exposed individual. The present study aims to identify new signatures of RIGI using data mining approach followed by validation of selected hub genes in mouse model. Using microarray datasets from Gene Expression Omnibus database, differentially expressed genes were identified. Pathway analysis suggested lipid metabolism as one of the predominant pathways altered in irradiated GI tissue. A protein-protein interaction network revealed top 08 hub genes related to lipid metabolism, namely Fabp1, Fabp2, Fabp6, Npc1l1, Ppar-α, Abcg8, Hnf-4α, and Insig1. qRT-PCR analysis revealed significant up-regulation of Fabp6 and Hnf-4α and down-regulation of Fabp1, Fabp2 and Insig1 transcripts in irradiated intestine. Radiation dose and time kinetics study revealed that the selected 05 genes were altered differentially in the irradiated intestine. Extensive alteration in lipid profiles and modification was observed in irradiated intestine. Finding suggests that lipid metabolism is one of the key targets of radiation and its mediators may act as biomarkers in detection and progression of RIGI.

Black beans (Glycine max (L.) Merrill) included in a multi-grain rice reduce total cholesterol and enhance antioxidant capacity in high-fat diet-induced obese mice

This study investigated the effects of black bean (BB) supplementation on the growth performance, lipid metabolism, and antioxidant capacity of high-fat diet-induced obese mice. The results demonstrated that although the inclusion of BBs led to increased body weight, total energy intake, and feed efficiency ratio, it did not significantly alter the overall body composition, including adiposity. Notably, BB consumption reduced total cholesterol levels, suggesting its potential to manage dyslipidemia and reduce the risk of atherosclerotic cardiovascular diseases. Furthermore, BBs significantly enhanced in the total antioxidant capacity, as indicated by the notable increase in both the total antioxidant capacity and superoxide dismutase activity. These findings provide significant insights into the promising health benefits of BBs in the context of metabolic syndrome and related health complications.

Nanometabolomics Elucidated Biological Prospective of Mo4/3B2-x Nanosheets: Toward Metabolic Reprogramming of Amino Acid Metabolism

Mo4/3B2-x nanosheets are newly developed, and 2D transition metal borides (MBene) were reported in 2021, but there is no report on their further applications and modification; hence, this article sheds light on the significance of potential biological prospects for future biomedical applications. Therefore, elucidation of the biocompatibility, biotoxicology, and bioactivity of Mo4/3B2-x nanosheets has been an urgent need to be fulfilled. Nanometabolomics (also referred as nanomaterials-based metabolomics) was first proposed and utilized in our previous work, which specialized in interpreting nanomaterials-induced metabolic reprogramming through aqueous metabolomics and lipidomics approach. Hence, nanometabolomics could be considered as a novel concept combining nanoscience and metabolomics to provide bioinformation on nanomaterials' biomedical applications. In this work, the safe range of concentration (<50 mg/L) with good biosafety toward human umbilical vein endothelial cells (HUVECs) was discovered. The low concentration (5 mg/L) and high concentration (50 mg/L) of Mo4/3B2-x nanosheets were utilized for the in vitro Mo4/3B2-x-cell interaction. Nanometabolomics has elucidated the biological prospective of Mo4/3B2-x nanosheets via monitoring its biocompatibility and metabolic shift of HUVECs. The results revealed that 50 mg/L Mo4/3B2-x nanosheets could lead to a stronger alteration of amino acid metabolism with disturbance of the corresponding amino acid-related pathways (including amino acid metabolism, amino acid degradation, fatty acid biosynthesis, and lipid biosynthesis and metabolism). These interesting results were closely involved with the oxidative stress and production of excess ROS. This work could be regarded as a pathbreaking study on Mo4/3B2-x nanosheets at a biological level, which also designates their further biochemical, medical, and industrial application and development based on nanometabolomics bioinformation.

mRNA Treatment Rescues Niemann-Pick Disease Type C1 in Patient Fibroblasts

Messenger RNA (mRNA) holds great potential as a disease-modifying treatment for a wide array of monogenic disorders. Niemann-Pick disease type C1 (NP-C1) is an ultrarare monogenic disease that arises due to loss-of-function mutations in the NPC1 gene, resulting in the entrapment of unesterified cholesterol in the lysosomes of affected cells and a subsequent reduction in their capacity for cholesterol esterification. This causes severe damage to various organs including the brain, liver, and spleen. In this work, we describe the use of NPC1-encoded mRNA to rescue the protein insufficiency and pathogenic phenotype caused by biallelic NPC1 mutations in cultured fibroblasts derived from an NP-C1 patient. We first evaluated engineering strategies for the generation of potent mRNAs capable of eliciting high protein expression across multiple cell types. We observed that "GC3" codon optimization, coupled with N1-methylpseudouridine base modification, yielded an mRNA that was approximately 1000-fold more potent than wild-type, unmodified mRNA in a luciferase reporter assay and consistently superior to other mRNA variants. Our data suggest that the improved expression associated with this design strategy was due in large part to the increased secondary structure of the designed mRNAs. Both codon optimization and base modification appear to contribute to increased secondary structure. Applying these principles to the engineering of NPC1-encoded mRNA, we observed a normalization in NPC1 protein levels after mRNA treatment, as well as a rescue of the mutant phenotype. Specifically, mRNA treatment restored the cholesterol esterification capacity of patient cells to wild-type levels and induced a significant reduction in both unesterified cholesterol levels (>57% reduction compared to Lipofectamine-treated control in a cholesterol esterification assay) and lysosome size (157 μm² reduction compared to Lipofectamine-treated control). These findings show that engineered mRNA can correct the deficit caused by NPC1 mutations. More broadly, they also serve to further validate the potential of this technology to correct diseases associated with loss-of-function mutations in genes coding for large, complex, intracellular proteins.

Stiffness and Aging in Cardiovascular Diseases: The Dangerous Relationship between Force and Senescence

Biological aging is a process associated with a gradual decline in tissues' homeostasis based on the progressive inability of the cells to self-renew. Cellular senescence is one of the hallmarks of the aging process, characterized by an irreversible cell cycle arrest due to reactive oxygen species (ROS) production, telomeres shortening, chronic inflammatory activation, and chromatin modifications. In this review, we will describe the effects of senescence on tissue structure, extracellular matrix (ECM) organization, and nucleus architecture, and see how these changes affect (are affected by) mechano-transduction. In our view, this is essential for a deeper understanding of the progressive pathological evolution of the cardiovascular system and its relationship with the detrimental effects of risk factors, known to act at an epigenetic level.

Interaction between visceral adiposity and ambient air pollution on LDL cholesterol level in Korean adults

BACKGROUND

Although previous reports have found that obesity intensifies the negative impact of long-term air pollution exposure on the low-density lipoprotein-cholesterol (LDL-C) level, few studies have examined whether the type of abdominal adiposity, such as visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and the visceral-to-subcutaneous fat ratio (VSR) affects this relationship. We investigated the association between ambient air pollution and LDL-C in Korean adults and identified whether this association is different by the type of abdominal adiposity.

METHODS

A total of 2737 adults were included. Abdominal fat areas were quantified by computed tomography, and the annual average concentration of air pollutants was included in this analysis.

RESULTS

In the total sample, none of the air pollutants was associated with LDL-C level in either the crude or adjusted model (all p > 0.05). The association was not significant even in subgroups stratified according to the obesity status defined by body mass index, and no interaction on the LDL-C level was also found (all p_int > 0.05). In the subgroup analysis stratified according to adiposity level, particulate matter with an aerodynamic diameter of ≤10 μm (PM₁₀) [β (SE) = 3.58 (1.59); p = 0.0245] and sulfur dioxide (SO₂) exposures [β (SE) = 2.71 (1.27); p = 0.0330] in the high-VAT group were associated with the increased LDL-C level. Interactions on LDL-C level were also found between VAT level and ambient air pollutants such as PM₁₀ and SO₂ (both p_int < 0.05). In the analysis of the VSR, PM₁₀ exposure showed a significant interaction on LDL level (p_int = 0.0032). However, the strength of these associations was not significant across all SAT subgroup (all p_int > 0.05).

CONCLUSIONS

In conclusion, we found that association between air pollution exposure and LDL-C level is different by abdominal fat distribution.

Isolation of Prunin FromBauhinia variegataand Its Antioxidant Activity in Rats Fed an Atherogenic Diet

Atherosclerosis is no longer a disease attributed mainly to high cholesterol content in the body; it has come to be regarded as a chronic inflammatory disease with an autoimmune component. The purpose of this study was to investigate the effect of the prunin fraction (PF) isolated from the ethanolic extract of Bauhinia variegata against the release of various proinflammatory mediators in rats fed an atherogenic diet. The diet was administered orally to Sprague Dawley rats for 60 days to induce atherosclerosis. The blood serum of the rats was used to estimate the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), thiobarbituric acid reactive substance, catalase, total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein using assay kits. Other physical parameters, such as body weight, feed intake, and systolic blood pressure, were also determined during the study. The results showed a significant protective effect of the PF against diet-induced atherosclerosis by decreasing the levels of proinflammatory mediators such as TNF-α and IL-6. Rats treated with PF (20 and 40 mg/kg) showed a change in systolic blood pressure and a reduction in oxidative stress induced by the atherogenic diet. Reduction in body weight and modulation of food intake were observed in PF-treated rats, which indicated atheroprotective, hypolipidemic, and antioxidant effects. The study concludes that the atheroprotective properties of PF are due to effects on the initial phase of plaque formation to thrombus formation. This study may help researchers to find a better alternative for selecting optimal therapies and preventing plaque formation. Future Significance: This article focuses on the molecular mechanisms involved in the evolution of atherosclerotic plaques and different targets that act at the starting stage of the plaque to thrombus formation. This may pave the way for selecting optimal therapies and preventing plaque complications.

Arbutin prevents alterations in mitochondrial and lysosomal enzymes in isoproterenol-induced myocardial infarction: An in vivo study

The present study demonstrated the protective effects of arbutin (ARB) on hyperlipidemia, mitochondrial, and lysosomal membrane damage and on the DNA damage in rats with isoproterenol (ISO)-induced myocardial infarction (MI). Rats were pretreated with ARB (25 and 50 mg/kg body weight (bw)) for 21 days. After pretreatment with ARB, MI was induced by subcutaneous injection of ISO (60 mg/kg bw) for two consecutive days at an interval of 24 h. The levels of TC, TG, and FFA were increased and decreased the level of PL in the heart tissue of ISO-induced MI rats. Very-low-density lipoprotein cholesterol and low-density lipoprotein cholesterol were increased while high-density lipoprotein cholesterol was decreased in the plasma of ISO-administered rats. A heart mitochondrial fraction of the ISO rats showed a significant decrease in the activities of mitochondrial enzymes isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase. The activities of lysosomal enzymes (β-glucosidase, β-glucuronidase, α-galactosidase, β-galactosidase, cathepsin-B, and cathepsin-D) were increased significantly in the heart tissue homogenate of disease control rats. In ISO-induced MI, rat’s significant increase in the percentage of tail DNA and tail length, and a decrease in the level of head DNA were also observed. ARB administration to MI rats brought all these parameters to near normality, showing the protective effect of ARB against MI in rats. The results of this study demonstrated that the 50 mg/kg bw of ARB shows higher protection than 25 mg/kg bw against ISO-induced damage.

Zygophyllum album saponins prevent atherogenic effect induced by deltamethrin via attenuating arterial accumulation of native and oxidized LDL in rats

The current study aimed to examine, for the first time, the relationship between exposure to deltamethrin (DLM) and atherogenic lipid profile disorders in adult Wistar rats, as well as, to verify the mechanism of the beneficial role of Zygophyllum album leaves extracts (ZALE). The experimental study was assessed using DLM (4 mg/kg b.w) either alone or co administered with ZALE (400 mg/kg b.w) orally for 90 days in rats. RP-HPLC-DAD-ESI-QTOF-MS was used to identify the bioactive metabolites present in ZALE. Plasmatic and aortic total cholesterol (TC), LDL-cholesterol (LDL-C), native LDL (LDL-apo B-100) and oxidized LDL (ox-LDL) were evaluated using auto-analyzer and a sandwich ELISA, respectively. The protein expressions of LDLR (native LDL receptor) and CD36 (Scavenger receptor class B) were evaluated in aorta or liver with a Western blot. The pathology has been confirmed with lipid stain (Oil Red O). Phytochemicals analysis revealed the presence of fifteen saponins in ZALE. Rats intoxicated with DLM revealed a significant increase in plasmatic and aortic lipid profile (TC, LDL-C, LDL-apo B-100 and ox-LDL), as well as, the concentration of the plasmatic cytokines include TNF-α, IL-2 and IL-6, compared to control. Hepatic native LDL and aortic CD36 receptor expression were increased in DLM treated group, however aortic LDL-R does not present any modification, when compared to control. The detected disturbances in lipid parameters were supported by Oil Red O applied. Due to their antioxidant activity, the bioactive compounds in ZALE as powerful agents able to prevent the pro-atherogenic effect observed in DLM-treated animals. These metabolites modulated most of inflammatory markers, prevented accumulation of lipid and lipoprotein biomarkers, regulated the major receptor regulators of hepatic cholesterol metabolism, as well as normalize lipid distribution in liver and aorta tissue.

Cardioprotective Effect of Croton macrostachyus Stem Bark Extract and Solvent Fractions on Cyclophosphamide-Induced Cardiotoxicity in Rats

Objective

To evaluate the antioxidant and cardioprotective activities of stem bark extract and solvent fractions of Croton macrostachyus on cyclophosphamide-induced cardiotoxicity in rats. Materials and Methods. DPPH free radical scavenging assay method was used to determine antioxidant activity whereas Sprague-Dawley rats were used to evaluate the cardioprotective activity. Except for the normal control, all groups were subjected to cyclophosphamide (200 mg/kg, i.p.) toxicity on the first day. Enalapril at 10 mg/kg was used as a reference. The hydromethanolic crude extract (100, 200, and 400 mg/kg) and aqueous and ethyl acetate fractions (100 and 200 mg/kg, each) were administered for 10 days. The cardioprotective activities were evaluated using cardiac biomarkers such as Troponin I, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total cholesterol (TC), triglyceride (TG), and histopathological studies of heart tissue.

Results

Crude extract and ethyl acetate and aqueous fractions exhibited free radical scavenging activities at IC₅₀ of 594 μg/mL, 419 μg/mL, and 716 μg/mL, respectively. Crude extract at 400 mg/kg decreased the levels of troponin, AST, ALT, and ALP to 0.29 ± 0.06 ng/mL, 103.00 ± 7.63 U/L, 99.80 ± 6.18 U/L, and 108.80 ± 8.81 U/L, respectively. In addition, ethyl acetate fraction at 200 mg/kg decreased the levels of troponin, AST, ALT, and ALP to 0.22 ± 0.02 ng/mL, 137.00 ± 14.30 U/L, 90.33 ± 6.13 U/L, and 166.67 ± 13.50 U/L, respectively, compared with the cyclophosphamide control group.

Conclusions

Croton macrostachyus possesses cardioprotective activities and it could be a possible source of treatment for cardiotoxicity induced by cyclophosphamide.

Silymarin Ameliorates Acrylamide-Induced Hyperlipidemic Cardiomyopathy in Male Rats

Acrylamide (AA) is a well-known potent carcinogen and neurotoxin that has been recently linked to atherosclerotic pathogenesis. The present study is aimed at investigating the protective effect of silymarin (SIL) as an antioxidant against AA-induced hyperlipidemic cardiomyopathy in male rats. The obtained results showed that animals exposed to AA exhibited a significant increase in the levels of cardiac serum markers, serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol with a significant decrease in high-density lipoprotein cholesterol. Furthermore, AA intoxication significantly increased the malondialdehyde level (a hallmark of lipid peroxidation) and reduced antioxidant enzyme activities (i.e., superoxide dismutase, catalase, and glutathione peroxidase). SIL administration significantly attenuated all these biochemical perturbations in AA-treated rats, except for the decreased high-density lipoprotein cholesterol. Our results were confirmed by histopathological assessment of the myocardium. In conclusion, this study demonstrated a beneficial effect of SIL therapy in the prevention of AA-induced cardiotoxicity by reversing the redox stress and dyslipidemia in experimental animals.

Protein and lipid homeostasis altered in rat macrophages after exposure to metallic oxide nanoparticles

Metal oxide nanoparticles (NPs), such as ZnO, ZnFe₂O₄, and Fe₂O₃, are widely used in industry. However, little is known about the cellular pathways involved in their potential toxicity. Here, we particularly investigated the key molecular pathways that are switched on after exposure to sub-toxic doses of ZnO, ZnFe₂O₄, and Fe₂O₃ in the in vitro rat alveolar macrophages (NR8383). As in our model, the calculated IC₅₀ were respectively 16, 68, and more than 200 μg/mL for ZnO, ZnFe₂O₄, and Fe₂O₃; global gene and protein expression profiles were only analyzed after exposure to ZnO and ZnFe₂O₄ NPs. Using a rat genome microarray technology, we found that 985 and 1209 genes were significantly differentially expressed in NR8383 upon 4 h exposure to ¼ IC₅₀ of ZnO and ZnFe₂O₄ NPs, respectively. It is noteworthy that metallothioneins were overexpressed genes following exposure to both NPs. Moreover, Ingenuity Pathway Analysis revealed that the top canonical pathway disturbed in NR8383 exposed to ZnO and ZnFe₂O₄ NPs was eIF2 signaling involved in protein homeostasis. Quantitative mass spectrometry approach performed from both NR8383 cell extracts and culture supernatant indicated that 348 and 795 proteins were differentially expressed upon 24 h exposure to ¼ IC₅₀ of ZnO and ZnFe₂O₄ NPs, respectively. Bioinformatics analysis revealed that the top canonical pathways disturbed in NR8383 were involved in protein homeostasis and cholesterol biosynthesis for both exposure conditions. While VEGF signaling was specific to ZnO exposure, iron homeostasis signaling pathway was specific to ZnFe₂O₄ NPs. Overall, the study provides resource of transcriptional and proteomic markers of response to ZnO and ZnFe₂O₄ NP-induced toxicity through combined transcriptomics, proteomics, and bioinformatics approaches.

Measurement of the 100 MHz EMF radiation in vivo effects on zebrafish D. rerio embryonic development: A multidisciplinary study

The augmented exposure of both environment and human being to electromagnetic waves and the concomitant lack of an unequivocal knowledge about biological consequences of these radiations, raised public interest on electromagnetic pollution. In this context, the present study aims to evaluate the biological effects on zebrafish (ZF) embryos of 100 MHz radiofrequency electromagnetic field (RF-EMF) exposure through a multidisciplinary protocol. Because of the shared synteny between human and ZF genomes that validated its use in biomedical research, toxicology and developmental biology studies, ZF was here selected as experimental model and a measurement protocol and biological analyses have been set up to clearly discriminate between RF-EMF biological and thermal effects. The results showed that a 100 MHz EMF was able to affect ZF embryonic development, from 24 to 72 h post fertilization (hpf) in all the analyzed pathways. Particularly, at the 48 hpf stage, a reduced growth, an increased transcription of oxidative stress genes, the onset of apoptotic/autophagic processes and a modification in cholesterol metabolism were detected. ZF embryos faced stress induced by EMF radiation by triggering detoxification mechanisms and at 72 hpf they partially recovered from stress reaching the hatching time in a comparable way respect to the control group. Data here obtained showed unequivocally the in vivo effects of RF-EMF on an animal model, excluding thermal outcomes and thus represents the starting point for more comprehensive studies on dose response effects of electromagnetic fields radiations consequences.

Analysis of oxidative stress-related markers in critically ill polytrauma patients: An observational prospective single-center study

Critically ill polytrauma patients have increased production of free radicals (FRs) and consequent alterations in biochemical pathways, as well as disruption of cellular integrity, due to increased lipid peroxidation. The aim of this study was to investigate several biomarkers associated with increased oxidative stress in critically ill polytrauma patients, and to evaluate the effect of antioxidant treatment on the clinical outcome in these patients. A total of 67 polytrauma patients from an intensive care unit met the selection criteria. Antiox group included 35/67 patients who received antioxidant therapy, while 32/67 patients without antioxidant treatment were considered as control group. Antioxidant therapy consisted of simultaneous administration of Vitamin C (sodium ascorbate) and N-acetylcysteine, through continuous intravenous infusion. Clinical and paraclinical evaluation of the patients was performed daily until discharge or death. At admission, laboratory parameters did not differ significantly between two groups. At discharge/upon death, statistically significant differences in favor of Antiox group were observed in the following parameters: thrombocytes, activated partial thromboplastin time, prothrombin time, total bilirubin, total cholesterol, high-density lipoproteins, low-density lipoproteins, erythrocyte sedimentation rate, interleukin 6 (all p = 0.0001), total protein (p = 0.0005), serum albumin (p = 0.0004), lactate dehydrogenase (p = 0.0006), and C-reactive protein (p = 0.0014). Starting from day 5, the APACHE II score was significantly decreased in Antiox versus control group (p < 0.05). Finally, the sepsis incidence and mortality rate were significantly lower in Antiox group (p < 0.05). Decreasing the level of oxidative stress by antioxidant substances significantly correlated with a better prognosis and outcome in our patients. Further studies should elucidate more clearly the mechanism of action of antioxidants in critically ill polytrauma patients.

Gestational diabetes mellitus modulates cholesterol homeostasis in human fetoplacental endothelium

Gestational diabetes mellitus (GDM) is associated with excessive oxidative stress which may affect placental vascular function. Cholesterol homeostasis is crucial for maintaining fetoplacental endothelial function. We aimed to investigate whether and how GDM affects cholesterol metabolism in human fetoplacental endothelial cells (HPEC). HPEC were isolated from fetal term placental arterial vessels of GDM or control subjects. Cellular reactive oxygen species (ROS) were detected by H₂DCFDA fluorescent dye. Oxysterols were quantified by gas chromatography-mass spectrometry analysis. Genes and proteins involved in cholesterol homeostasis were detected by real-time PCR and immunoblotting, respectively. Cholesterol efflux was determined from [³H]-cholesterol labeled HPEC and [¹⁴C]-acetate was used as cholesterol precursor to measure cholesterol biosynthesis and esterification. We detected enhanced formation of ROS and of specific, ROS-derived oxysterols in HPEC isolated from GDM versus control pregnancies. ROS-generated oxysterols were simultaneously elevated in cord blood of GDM neonates. Liver-X receptor activation in control HPEC by synthetic agonist TO901319, 7-ketocholesterol, or 7β-hydroxycholesterol upregulated ATP-binding cassette transporters (ABC)A1 and ABCG1 expression, accompanied by increased cellular cholesterol efflux. Upregulation of ABCA1 and ABCG1 and increased cholesterol release to apoA-I and HDL₃ (78 ± 17%, 40 ± 9%, respectively) were also observed in GDM versus control HPEC. The LXR antagonist GGPP reversed ABCA1 and ABCG1 upregulation and reduced the increased cholesterol efflux in GDM HPEC. Similar total cellular cholesterol levels were detected in control and GDM HPEC, while GDM enhanced cholesterol biosynthesis along with upregulated 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and sterol O-acyltransferase 1 (SOAT1) mRNA and protein levels. Our results suggest that in GDM cellular cholesterol homeostasis in the fetoplacental endothelium is modulated via LXR activation and helps to maintain its proper functionality.

Stigmasterol prevents glucolipotoxicity induced defects in glucose-stimulated insulin secretion

Type 2 diabetes results from defects in both insulin sensitivity and insulin secretion. Elevated cholesterol content within pancreatic β-cells has been shown to reduce β-cell function and increase β-cell apoptosis. Hyperglycemia and dyslipidemia contribute to glucolipotoxicity that leads to type 2 diabetes. Here we examined the capacity of glucolipotoxicity to induce free cholesterol accumulation in human pancreatic islets and the INS-1 insulinoma cell line. Glucolipotoxicity treatment increased free cholesterol in β-cells, which was accompanied by increased reactive oxygen species (ROS) production and decreased insulin secretion. Addition of AAPH, a free radical generator, was able to increase filipin staining indicating a link between ROS production and increased cholesterol in β-cells. We also showed the ability of stigmasterol, a common food-derived phytosterol with anti-atherosclerotic potential, to prevent the increase in both free cholesterol and ROS levels induced by glucolipotoxicity in INS-1 cells. Stigmasterol addition also inhibited early apoptosis, increased total insulin, promoted actin reorganization, and improved insulin secretion in cells exposed to glucolipotoxicity. Overall, these data indicate cholesterol accumulation as an underlying mechanism for glucolipotoxicity-induced defects in insulin secretion and stigmasterol treatment as a potential strategy to protect β-cell function during diabetes progression.

2-Hydroxypropyl-beta-cyclodextrin (HPβCD) reduces age-related lipofuscin accumulation through a cholesterol-associated pathway

Oxidative stress causes significant increases in both cholesterol uptake and intracellular accumulation of the aging biomarker lipofuscin. Here we show that HPβCD addition mitigates these adverse effects in human fibroblasts by significantly reducing LDLr and SREBP1 gene expression. In the absence of oxidative stress, HPβCD addition induces a paradoxical response, increasing cholesterol accumulation (but not lipofuscin) via upregulation of cholesterol biosynthesis. These two distinct, but opposite effects highlight a previously overlooked therapeutic consideration: the cholesterol content of the treated cell determines which cholesterol pathways, either beneficial or harmful, are responsive to HPβCD.

Ginger Treatment Ameliorates Alcohol-induced Myocardial Damage by Suppression of Hyperlipidemia and Cardiac Biomarkers in Rats

Background:

Alcohol-induced hyperlipidemia is positively correlated with cardiovascular diseases. Several herbal extracts have been reported to protect the cardiac injury and suppress the hyperlipidemia. However, the effect of ginger extracts on alcohol-induced hyperlipidemia and associated myocardial damage remains unclear.

Objective:

This study investigated the cardio-protective properties of ginger ethanolic extract (Gt) against alcohol-induced myocardial damage, and further distinguished the association between hyperlipidemia and occurrence of myocardial damage in rats.

Materials and Methods:

Twenty four Wistar male albino rats (250 ± 20 g) were divided into four groups including, Normal control (NC) (0.9% NaCl), Ginger treated (Gt) (200 mg/Kg b.w.), Alcohol treated (At) (20% of 6g/kg b.w. alcohol), and Alcohol along with Ginger treatment (At+Gt). In this study, lipid profiles such as fatty acids, triglycerides, total cholesterol, phospholipids, low density lipoprotein and high density lipoproteins, and cardiac biomarkers, including LDH, AST, CK-MB, cTn-T and cTn-I were examined in rats. Furthermore, histopathological studies were also conducted.

Results:

We found that alcohol-induced myocardial damage was associated with increased lipid profile except high density lipoprotein in alcohol treated (20%, 6g/kg b.w.) rats compared with control. Ginger treatment significantly reduced the alcohol-induced lipid profiles except high density lipoproteins. Furthermore, elevated cardiac biomarkers activity with alcohol intoxication was substantially suppressed by ginger treatment. In addition, ginger treatment for 7-weeks significantly minimized the alcohol-induced myocardial damage.

Conclusion:

Our results concluded that ginger could protect alcohol-induced myocardial damage by suppression of hyperlipidemia and cardiac biomarkers.

SUMMARY

Ginger extract could alleviate the myocardial injury partially due to the suppression of circulating FFAs and TG levels.

Increased circulating cholesterol, LDL and phospholipids with alcohol intake were substantially suppressed by ginger treatment

Alcohol, induced an increase in cardiac damage biomarkers, CK-MB, cTn-T and cTn-I were remarkably suppressed by ginger treatment

Performed histopathological studies by transmission electron microscopy and light microscopy shows additional convincing evidence on ginger cardio-protective effects. The drastic changes were rehabilitated in cardiac tissue by ginger treatment may be it acts as a good antioxidant and possessing hypolipidemic activity.

Collectively, our findings confirm hypothesis that ginger has cardio protective potential through suppression of hyperlipidemia, preserving the tissue damage bio markers, cardiac biomarkers in plasma and preservation of histoarchitecture of myocytes.

Abbreviations used: Gt: Ginger Ethanolic Extract; NC: Normal Control; At: Alcohol treated; MI: Myocardial Infarction

Mangiferin protects rat myocardial tissue against cyclophosphamide induced cardiotoxicity

BACKGROUND

Mangiferin is a highly potent antioxidant present in mango leaves which is utilized for therapeutic purposes.

OBJECTIVE

The present study was undertaken to evaluate the cardioprotective effect of mangiferin against cyclophosphamide induced cardiotoxicity.

MATERIALS AND METHODS

Rats were treated with 100 mg/kg of mangiferin in alone and interactive groups for 10 days. Apart from normal and mangiferin control groups, all the groups were subjected to cyclophosphamide (200 mg/kg, i.p.) toxicity on Day 1 and effects of different treatments were analyzed by changes in serum biomarkers, tissue antioxidant levels, electrocardiographic parameters, lipid profile and histopathological evaluation.

RESULTS

Mangiferin treated group showed decrease in serum biomarker enzyme levels and increase in tissue antioxidant levels. Compared to cyclophosphamide control group, mangiferin treated animals showed improvement in lipid profile, electrocardiographic parameters, histological score and mortality.

CONCLUSION

The present findings clearly suggest the protective role of mangiferin as a powerful antioxidant preventing cardiotoxicity caused by cyclophosphamide.

Possible protective effect of royal jelly against cyclophosphamide induced prostatic damage in male albino rats; a biochemical, histological and immuno-histo-chemical study

Almost all the chemotherapy treat many cancer types effectively, but it leads to severe side effects. Chemotherapy like cyclophosphamide (CP) not works only on the active cells, such as cancer cells, but also acts on the healthy cells. Royal jelly (RJ) was reported to have a lot of therapeutic effects besides being an anti-oxidant and anti-cancer agent. The purpose of this study was to assess the possible protective role of RJ in ameliorating the toxic effects of CP overdose in the rat prostatic tissue. The rats were separated into 4 groups; control group, RJ group, CP group and RJ with CP group. Prostatic specimens were processed for biochemical, histological and immune-histo-chemical studies. The mean area fractions of eNOS and Bax expression were measured in all groups, and statistical analysis was carried out. The results showed that in CP treated group, there were marked biological changes in the form of significant increase in prostatic malondialdehyde (MDA) and C - reactive protein (CRP). Additionally there was a significant decrease in glutathione peroxidase (GPx) in prostatic tissue if compared with the control group. Furthermore, the histological changes showed marked acinar and stromal prostatic degeneration. Most prostatic acini showed less PAS reaction and more (eNOS and Bax) expression if compared with the control group. Concomitant administration of RJ with CP revealed a noticeable amelioration of these biochemical and histological changes. In conclusion, RJ provided biochemical and histo-pathological improvement in CP induced prostatic tissue toxicity. These findings revealed that this improvement was associated with a decrease in the tissue oxidative damage and apoptosis.

Cholesterol-lowering effect of astringent persimmon fruits (Diospyros kaki Thunb.) extracts

This study aimed to investigate the effects of ethanol extract of astringent persimmon on antioxidant activity, cholesterol, 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase activity, and mRNA expression of cholesterol metabolism-related genes in human hepatoma cell line (HepG2 cells). In the results, DPPH and ABTS radical scavenging activity showed that the different types cultivars of astringent persimmon was similar to Vitamin C as positive control. However, there are not significant differences among samples. In addition, our results showed that cholesterol amounts and HMG-CoA reductase activity were inhibited by astringent persimmon in HepG2 cells. Further, treatment with astringent persimmon upregulated the expression of LDL receptor and SREBP-2, and also increased the level of HDL-associated ABCA1. Taken together, our results indicate that astringent persimmon regulate cholesterol accumulation by inhibiting the oxidative stress and controlling the levels of LDL & HDLassociated gene.

Sundarban Honey Confers Protection against Isoproterenol-Induced Myocardial Infarction in Wistar Rats

The present study was designed to investigate the cardioprotective effects of Sundarban honey (SH) in rats with isoproterenol- (ISO-) induced myocardial infarction. Adult male Wistar Albino rats were pretreated with Sundarban honey (5 g/kg) daily for a period of 6 weeks. After the treatment period, ISO (85 mg/kg) was subcutaneously injected into the rats at 24 h intervals for 2 days. ISO-induced myocardial damage was indicated by increased serum cardiac specific troponin I levels and cardiac marker enzyme activities including creatine kinase-MB, lactate dehydrogenase, aspartate transaminase, and alanine transaminase. Significant increases in serum total cholesterol, triglycerides, and low-density lipoprotein-cholesterol levels were also observed, along with a reduction in the serum high-density lipoprotein-cholesterol level. In addition to these diagnostic markers, the levels of lipid peroxide products were significantly increased. The activities of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and glutathione reductase were significantly decreased in the hearts after ISO-induced myocardial infarction. However, pretreatment of ischemic rats with Sundarban honey brought the biochemical parameters to near normalcy, indicating the protective effect of Sundarban honey against ISO-induced ischemia in rats. Histopathological findings of the heart tissues further confirmed the biochemical findings, indicating that Sundarban honey confers protection against ISO-induced oxidative stress in the myocardium.

Amelioration of Isoproterenol-Induced Oxidative Damage in Rat Myocardium by Withania somnifera Leaf Extract

We investigated the protective role of Withania somnifera leaf extract (WSLEt) on isoproterenol- (ISO-) induced myocardial infarction (MI) in rats. Subcutaneous injection of ISO (85 mg/kg body weight (b.w.)) administered to rats for two consecutive days caused a significant increase in cardiac troponin I (cTnI) levels and serum lipid profiles, as well as the activities of some marker enzymes. In addition to these diagnostic markers, there were increased levels of lipid peroxidation (LPO) and decreased activities of enzymatic antioxidants (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRx), and glutathione-S-transferase (GST)) in the myocardium. However, oral pretreatment (100 mg/kg b.w.) with WSLEt for 4 weeks elicited a significant cardioprotective activity by lowering the levels of cTnI, lipid profiles, and marker enzymes. The levels of LPO products were also significantly decreased. Elevated activities of antioxidant enzymes were also observed in rats pretreated with WSLEt. As further confirmed histopathologically, our findings strongly suggest that the cardioprotective effect of WSLEt on myocardium experiencing ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidant system and an inhibition of LPO in the myocardial membrane. We conclude that WSLEt confers some protection against oxidative damage in ISO-induced MI in rats.

Arsenic-induced dyslipidemia in male albino rats: comparison between trivalent and pentavalent inorganic arsenic in drinking water

Background

Recent epidemiological evidences indicate close association between inorganic arsenic exposure via drinking water and cardiovascular diseases. However, the exact mechanism of this arsenic-mediated increase in cardiovascular risk factors remains enigmatic.

Methods

In order to investigate the effects of inorganic arsenic exposure on lipid metabolism, male albino rats were exposed to 50, 100 and 150 ppm arsenic as sodium arsenite and 100, 150 and 200 ppm arsenic as sodium arsenate respectively in their drinking water for 12 weeks.

Results

Dyslipidemia induced by the two arsenicals exhibited different patterns. Hypocholesterolemia characterised the effect of arsenite at all the doses, but arsenate induced hypercholesterolemia at the 150 ppm As dose. Hypertriglyceridemia was the hallmark of arsenate effect whereas plasma free fatty acids (FFAs) was increased by the two arsenicals. Reverse cholesterol transport was inhibited by the two arsenicals as evidenced by decreased HDL cholesterol concentrations whereas hepatic cholesterol was increased by arsenite (100 ppm As), but decreased by arsenite (150 ppm As) and arsenate (100 ppm As) respectively. Brain cholesterol and triglyceride were decreased by the two arsenicals; arsenate decreased the renal content of cholesterol, but increased renal content of triglyceride. Arsenite, on the other hand, increased the renal contents of the two lipids. The two arsenicals induced phospholipidosis in the spleen. Arsenite (150 ppm As) and arsenate (100 ppm As) inhibited hepatic HMG CoA reductase. At other doses of the two arsenicals, hepatic activity of the enzyme was up-regulated. The two arsenicals however up-regulated the activity of the brain enzyme. We observed positive associations between tissue arsenic levels and plasma FFA and negative associations between tissue arsenic levels and HDL cholesterol.

Conclusion

Our findings indicate that even though sub-chronic exposure to arsenite and arsenate through drinking water produced different patterns of dyslipidemia, our study identified two common denominators of dyslipidemia namely: inhibition of reverse cholesterol transport and increase in plasma FFA. These two denominators (in addition to other individual perturbations of lipid metabolism induced by each arsenical), suggest that in contrast to strengthening a dose-dependent effect phenomenon, the two forms of inorganic arsenic induced lipotoxic and non-lipotoxic dyslipidemia at “low” or “medium” doses and these might be responsible for the cardiovascular and other disease endpoints of inorganic arsenic exposure through drinking water.

Mitochondrial GWA Analysis of Lipid Profile Identifies Genetic Variants to Be Associated with HDL Cholesterol and Triglyceride Levels

It has been suggested that mitochondrial dysfunction has an influence on lipid metabolism. The fact that mitochondrial defects can be accumulated over time as a normal part of aging may explain why cholesterol levels often are altered with age. To test the hypothesis whether mitochondrial variants are associated with lipid profile (total cholesterol, LDL, HDL, and triglycerides) we analyzed a total number of 978 mitochondrial single nucleotide polymorphisms (mtSNPs) in a sample of 2,815 individuals participating in the population-based KORA F4 study. To assess mtSNP association while taking the presence of heteroplasmy into account we used the raw signal intensity values measured on the microarray and applied linear regression. Ten mtSNPs (mt3285, mt3336, mt5285, mt6591, mt6671, mt9163, mt13855, mt13958, mt14000, and mt14580) were significantly associated with HDL cholesterol and one mtSNP (mt15074) with triglycerides levels. These results highlight the importance of the mitochondrial genome among the factors that contribute to the regulation of lipid levels. Focusing on mitochondrial variants may lead to further insights regarding the underlying physiological mechanisms, or even to the development of innovative treatments. Since this is the first mitochondrial genome-wide association analysis (mtGWAS) for lipid profile, further analyses are needed to follow up on the present findings.

Cardioprotective effect of Saraca indica against cyclophosphamide induced cardiotoxicity in rats: a biochemical, electrocardiographic and histopathological study

Objectives:

Cardioprotective activity of alcoholic extract of Saraca indica (SI) bark was investigated against cyclophosphamide induced cardiotoxicity.

Materials and Methods:

Cardiotoxicity was induced in Wistar rats by administering cyclophosphamide (200 mg/kg, i.p.) single injection on first day of experimental period. Saraca indica (200 and 400 mg/kg, p.o.) was administered immediately after administration of cyclophosphamide on first day and daily for 10 days. The general observations and mortality were measured.

Results:

Cyclophosphamide administration significantly (p < 0.05) increased lipid peroxidation (LPO) and decreased the levels of antioxidant markers such as reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). Cyclophosphamide elevated the levels of biomarker enzymes like creatine kinase (CK), creatine kinase isoenzyme MB (CK-MB), lactate dehydrogenase (LDH), aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). Further, the cyclophosphamide treated rats showed changes in electrocardiogram (ECG) along with increased levels of cholesterol and triglycerides. Treatment with Saraca indica significantly (p < 0.05) reversed the status of cardiac biomarkers, ECG, oxidative enzymes and lipid profile in cyclophosphamide induced cardiotoxicity. Potential cardioprotective effect of Saraca indica was supported by histopathological examination that reduced severity of cellular damage of the myocardium.

Conclusion:

The biochemical, ECG and histopathology reports support the cardioprotective effect of Saraca indica which could be attributed to antioxidant activity.

Effect of ursolic acid on cardiac marker enzymes, lipid profile and macroscopic enzyme mapping assay in isoproterenol-induced myocardial ischemic rats

This study investigates the antihyperlipidemic effect of ursolic acid (UA) on isoproterenol (ISO) induced male albino Wistar rats. Myocardial ischemia was induced by subcutaneous injection of ISO (85 mg/kg BW) twice at an interval of 24 h, for two consecutive days. A significant increase in the activities of the serum marker enzymes [creatine kinase, creatine kinase-MB and lactate dehydrogenease (LDH)], a prominent expression of LDH 1 and LDH 2 isoenzymes, increased levels of plasma total cholesterol (TC), low density lipoprotein-cholesterol, very low density lipoprotein-cholesterol, triglycerides (TG), free fatty acids (FFA), phospholipids (PL) and atherogenic index and decreased level of high density lipoprotein-cholesterol were observed in ISO-induced rats. The levels of TC, TG and FFA increased and the level of PL decreased in the heart tissue of ISO-induced rats. Further, there was an increased DNA damage (Comet assay) and myocardium infarct size as observed by staining with triphenyltetrazolium chloride (TTC). UA was administered subcutaneously for 7 days at a dose of 40 mg/kg BW. UA administration to ischemic rats brought all these parameters to near normality showing the protective effect of UA on ISO-induced rats.

Impact of renal insufficiency on safety and efficacy of drug-eluting stents compared to bare-metal stents at 6 years

BACKGROUND

There is few information on the long-term efficacy and safety of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared to bare metal stents (BMS) in all-comer percutaneous coronary intervention (PCI)-patients complicated by renal insufficiency (RI).

OBJECTIVE

Our aim was to assess the 6-year clinical outcome of PCI-patients with RI treated exclusively with BMS, SES, or PES in our academic hospital.

METHODS

A total of 1382 patients, included in three cohorts of consecutive PCI-patients (BMS = 392; SES = 498; PES = 492), were categorized by creatinine clearance calculated by the Cockroft-Gault formula (normal kidney function ≥ 90; mild RI = 60-89; moderate RI < 60) and systematically followed for the occurrence of major adverse cardiac events (MACE).

RESULTS

Mortality rates were significantly higher for patients with moderate RI compared to mild RI and normal kidney function at 6 years (Kaplan-Meier estimate: moderate RI (34%) vs. mild RI (12%), P < 0.001; moderate RI (34%) vs. normal kidney function (8%), P < 0.001). After multivariate Cox-regression analysis, SES and PES decreased the occurrence of target-vessel revascularization (TVR) and MACE at 6 years in patients with a normal creatinine clearance compared to BMS [adjusted hazard ratio (aHR) = 0.48, 95% CI: 0.28-0.84; aHR = 0.75, 95% CI: 0.57-0.97, respectively] with no significant effect on mortality. Safety- and efficacy end points were comparable for the three stent types in patients with mild- and moderate renal function.

CONCLUSION

Patients with a normal creatinine clearance had significant improvement in TVR and MACE rates after SES- or PES implantation compared to BMS at 6 years. However, there was no superiority of both drug-eluting stents over BMS in safety and efficacy end points for patients with impaired renal function.

Probucol attenuates cyclophosphamide-induced oxidative apoptosis, p53 and Bax signal expression in rat cardiac tissues

Cyclophosphamide (CP) is a widely used in cancer chemotherapy and immunosuppression, which could cause toxicity of the normal cells due to its toxic metabolites. Probucol, cholesterol-lowering drug, acts as potential inhibitor of DNA damage and shows to protect against doxorubicin-induced cardiomyopathy by enhancing the endogenous antioxidant system including glutathione peroxidase, catalase and superoxide dismutase. This study examined the possible protective effects of probucol, a lipid-lowering compound with strong antioxidant properties, against CP-induced cardiotoxicity. This objective could be achieved through studying the gene expression-based on the possible protective effects of probucol against CP-induced cardiac failure in rats. Adult male Wistar albino rats were assigned into 4 treatment groups: Animals in the first (control) and second (probucol) groups were injected intraperitoneally with corn oil and probucol (61 mg/kg/day), respectively, for two weeks. Animals in the third (CP) and fourth (probucol plus CP) groups were injected with the same doses of corn oil and probucol (61 mg/kg/day), respectively, for one week before and one week after a single dose of CP (200 mg/kg, I.P.). The p53, Bax, Bcl2 and oxidative genes signal expression were measured by real time PCR. CP-induced cardiotoxicity was clearly observed by a significant increase in serum creatine phosphokinase isoenzyme (CK-MB) (117%), lactate dehydrogenase (LDH) (64%), free (69%) and esterified cholesterol (42%) and triglyceride (69%) compared to control group. In cardiac tissues, CP significantly increases the mRNA expression levels of apoptotic genes, p53 with 2 folds and Bax with 1.6 fold, and decreases the anti-apoptotic gene Bcl2 with 0.5 fold. Moreover, CP caused down-regulation of antioxidant genes, glutathione peroxidase, catalase, and superoxide dismutase and increased the lipid peroxidation and decreased adenosine triphosphate (ATP) (40%) and ATP/ADP (44%) in cardiac tissues. Probucol pretreatment not only counteracted significantly the CP-induced increase in cardiac enzymes and apoptosis but also it induced a significant increase in mRNA expression of antioxidant enzymes and improved ATP, ATP/ADP, glutathione (GSH) in cardiac tissues. In conclusion, data from the present study suggest that probucol prevents the development of CP-induced cardiotoxicity by a mechanism related, at least in part, to its ability to increase mRNA expression of antioxidant genes and to decrease apoptosis in cardiac tissues with the consequent improvement in mitochondrial oxidative phosphorylation and energy production.

C-reactive protein inhibits cholesterol efflux from human macrophage-derived foam cells

OBJECTIVE

The objective of this study was to determine the effects and potential mechanisms of C-reactive protein (CRP) on cholesterol efflux from human macrophage foam cells, which may play a critical role in atherogenesis.

METHODS AND RESULTS

Human THP-1 monocytes and peripheral blood mononuclear cells (PBMCs) were preincubated with acetylated LDL and [3H]-cholesterol to form foam cells, which were then treated with apolipoprotein A-I (apoA-I) or HDL for cholesterol efflux assay. Clinically relevant concentrations of CRP significantly reduced cholesterol efflux from THP-1 and PBMCs to apoA-I or HDL. CRP significantly decreased the expression of ATP-binding membrane cassette transporter A-1 (ABCA1) and ABCG1, whereas it increased superoxide anion production. Furthermore, CRP substantially activated ERK1/2 in THP-1-derived foam-like cells. Reducing superoxide anion by antioxidant seleno-L-methionine or SOD mimetic (MnTBAP) effectively abolished the CRP-induced decrease in cholesterol efflux and the expression of ABCA1 and ABCG1. Inhibiting ERK1/2 activation by its specific inhibitor PD98059 or by a dominant negative mutant of ERK2 could also block CRPs action on THP-1 cells.

CONCLUSIONS

CRP inhibits cholesterol efflux from human foam cells derived from THP-1 and PBMCs in vitro though oxidative stress, ERK1/2 activation, and downregulation of intracellular cholesterol transport molecules ABCA1 and ABCG1.

Human immunodeficiency virus protease inhibitor ritonavir inhibits cholesterol efflux from human macrophage-derived foam cells

Clinical use of human immunodeficiency virus protease inhibitors such as ritonavir may be associated with cardiovascular disease. The objective of this study was to determine the effects and molecular mechanisms of ritonavir on cholesterol efflux from human macrophage-derived foam cells, which is a critical factor of atherogenesis. Human THP-1 monocytes and peripheral blood mononuclear cells were preincubated with acetylated low-density lipoprotein and [(3)H]cholesterol to form foam cells, which were then treated with apolipoprotein A-I for cholesterol efflux assay. A clinically relevant concentration of ritonavir (15 mumol/L) significantly reduced cholesterol efflux from THP-1 and peripheral blood mononuclear cells to apolipoprotein A-I by 30 and 29%, respectively, as compared with controls. In addition, ritonavir significantly decreased the expression of scavenger receptor B1 and caveolin-1, whereas it significantly increased superoxide anion production and activated extracellular signal-regulated kinase (ERK) 1/2 in macrophages. Mitochondrial membrane potential was significantly reduced, whereas NADPH oxidase subunits were increased in ritonavir-treated macrophages. Consequently, the antioxidant seleno-l-methionine, the specific ERK1/2 inhibitor PD98059, or infection of a recombinant adenovirus encoding the dominant-negative form of ERK2 effectively blocked ritonavir-induced decrease of cholesterol efflux. Therefore, human immunodeficiency virus protease inhibitor ritonavir significantly inhibits cholesterol efflux from macrophages, which may be mediated by mitochondrial dysfunction, oxidative stress, ERK1/2 activation, and down-regulation of scavenger receptor B1 and caveolin-1.

Differential effects of oxidized LDL on apolipoprotein AI and B synthesis in HepG2 cells

Oxidized low-density lipoproteins (Ox-LDL) are key elements in atherogenesis. Apolipoprotein AI (apoAI) is an active component of the antiatherogenic high-density lipoproteins (HDL). In contrast, plasma apolipoprotein B (apoB), the main component of LDL, is highly correlated with coronary risk. Our results, obtained in HepG2 cells, show that Ox-LDL, unlike native LDL, leads to opposite effects on apoB and apoAI, namely a decrease in apoAI and an increase in apoB secretion as evaluated by [(3)H]leucine incorporation and specific immunoprecipitation. Parallel pulse-chase studies show that Ox-LDL impaired apoB degradation, whereas apoAI degradation was increased and mRNA levels were decreased. We also found that enhanced lipid biosynthesis of both triglycerides and cholesterol esters was involved in the Ox-LDL-induced increase in apoB secretion. Our data suggest that the increase in apoB and decrease in apoAI secretion may in part contribute to the known atherogenicity of Ox-LDL through an elevated LDL/HDL ratio, a strong predictor of coronary risk in patients.

Protective effect of dl-α-lipoic acid on cyclophosphamide induced hyperlipidemic cardiomyopathy

Cyclophosphamide is a potent alkylating agent used in cancer chemotherapy and immunosuppression. The present study is aimed at evaluating the role of a potent antioxidant lipoic acid in cyclophosphamide induced hyperlipidemic cardiomyopathy. Adult male Wistar rats were divided into four treatment groups. Two groups received single intraperitoneal injection of cyclophosphamide (200 mg/kg body weight) to induce cardiotoxicity, one of these groups received lipoic acid treatment (25 mg/kg body weight, orally for 10 days). A vehicle treated control group and a lipoic acid drug control were also included. Cyclophosphamide administration resulted in abnormal elevation of serum lipids. Similarly in the cardiac tissue, the levels of free cholesterol, esterified cholesterol, triglycerides were increased significantly (P<0.05) while the levels of phospholipids and free fatty acids were reduced significantly unlike serum (P<0.05). Serum Low Density Lipoprotein (LDL) and Very Low Density Lipoprotein (VLDL) cholesterol increased significantly (P<0.05) while High Density Lipoprotein (HDL) cholesterol (P<0.05) decreased significantly when compared to controls. These changes corroborated with the abnormal distortion in the activities of lipid metabolizing enzymes in cyclophosphamide treated group. Supplementation of lipoic acid reverted these abnormalities in the lipid levels and activities of lipid metabolizing enzymes to near normalcy after cyclophosphamide administration.

Oxidative renal injury and lipoprotein oxidation in hypercholesterolemic atherogenesis: Role of eicosapentaenoate-lipoate (EPA-LA) derivative

Hypercholesterolemia, an independent risk factor for increased oxidative renal injury, is associated with the formation of oxidized low-density lipoprotein. Production of reactive oxygen species and nitrogen species have been implicated in diet-induced hypercholesterolemia, principally as means of oxidising low-density lipoproteins. This in turn initiates the accumulation of cholesterol in macrophages, which sets key event in the initiation of atherosclerosis. The aim of the present work is to evaluate the effects of eicosapentaenoic acid (EPA), DL alpha-lipoic acid (LA) and eicosapentaenoate-lipoate derivative (EPA-LA) in controlling the atherogenic disturbances. Four groups of male Wistar rats were fed with a high cholesterol diet (rat chow supplemented with 4% cholesterol and 1% cholic acid; HCD) for 30 days. Among them, 3 groups of rats were treated with either EPA (35 mg/kg body weight/day, oral gavage), LA (20 mg/kg body weight/day, oral gavage) or EPA-LA derivative (50 mg/kg body weight/day, oral gavage) from 16th day to 30th day of the experimental period. Abnormal increase in the levels of reactive oxygen species, 3-nitrotyrosine, malondialdehyde and protein carbonyl as well as an elevation in the activities of xanthine oxidase, lactate dehydrogenase, alkaline phosphatase and acid phosphatase was observed in renal tissue of HCD fed rats. HCD fed rats also showed an increased susceptibility of the apo B-containing lipoproteins to in vitro oxidation. These changes were restored partially in the EPA and LA administered groups. However, the combined derivative EPA-LA almost ameliorated the hypercholesterolemic-oxidative changes in the HCD fed rats.

Protective role of eicosapentaenoate-lipoate (EPA-LA) derivative in combating oxidative hepatocellular injury in hypercholesterolemic atherogenesis

The aim of the present study is to evaluate the effect of eicosapentaenoic acid (EPA), dl-alpha-lipoic acid (LA) and eicosapentaenoate-lipoate (EPA-LA) derivative on the atherogenic disturbances in hypercholesterolemic atherogenic animals. Eight groups of male Wistar rats were employed in this study, wherein four groups were fed with a high cholesterol diet (rat chow supplemented with 4% cholesterol and 1% cholic acid; HCD) for 30 days, among which, three groups of rats were also treated with either EPA (35 mg/kg body weight/day, oral gavage), LA (20 mg/kg body weight/day, oral gavage) or EPA-LA derivative (50 mg/kg body weight/day, oral gavage) commencing from 16th day of the experimental period. The remaining four groups served as control and EPA, LA and EPA-LA derivative treated drug controls. Abnormal increases in the levels of malondialdehyde, protein carbonyl and 8-hydroxy-2-deoxyguanosine, as well as depressed antioxidants status, were observed in hepatic tissue of HCD fed rats. HCD induced abnormal elevation in the activities of hepatic lactate dehydrogenase, aminotransferases and alkaline phosphatase (ALP) and was accompanied by increased hepatic cholesterol level and altered fatty changes in the histology of liver. These changes were restored partially in the EPA and LA administered groups. However, the combined derivative EPA-LA almost ameliorated the hypercholesterolemic-oxidative changes in the HCD fed rats. The results of this study present oxidative injury induced by hypercholesterolemic diet and administration of the combination treatment of EPA-LA afforded sound protection against lipemic-oxidative injury.

Cholesterogenic lanosterol 14alpha-demethylase (CYP51) is an immediate early response gene

Lanosterol 14alpha-demethylase (CYP51) responds to cholesterol feedback regulation through sterol regulatory element binding proteins (SREBPs). The proximal promoter of CYP51 contains a conserved region with clustered regulatory elements: GC box, cAMP-response elements (CRE-like), and sterol regulatory element (SRE). In lipid-rich (SREBP-poor) conditions, the CYP51 mRNA drops gradually, the promoter activity is diminished, and no DNA-protein complex is observed at the CYP51-SRE1 site. The majority of cAMP-dependent transactivation is mediated through a single CRE (CYP51-CRE2). Exposure of JEG-3 cells to forskolin, a mediator of the cAMP-dependent signaling pathway, provokes an immediate early response of CYP51, which has not been described before for any cholesterogenic gene. The CYP51 mRNA increases up to 4-fold in 2 h and drops to basal level after 4 h. The inducible cAMP early repressor (ICER) is involved in attenuation of transcription. Overexpressed CRE-binding protein (CREB)/CRE modulator (CREM) transactivates the mouse/human CYP51 promoters containing CYP51-CRE2 independently of SREBPs, and ICER decreases the CREB-induced transcription. Besides the increased CYP51 mRNA, forskolin affects the de novo sterol biosynthesis in JEG-3 cells. An increased consumption of lanosterol, a substrate of CYP51, is observed together with modulation of the postlanosterol cholesterogenesis, indicating that cAMP-dependent stimuli cross-talk with cholesterol feedback regulation. CRE-2 is essential for cAMP-dependent transactivation, whereas SRE seems to be less important. Interestingly, when CREB is not limiting, the increasing amounts of SREBP-1a fail to transactivate the CYP51 promoter above the CREB-only level, suggesting that hormones might have an important role in regulating cholesterogenesis in vivo.

In vitro models to evaluate acute and chronic injury to the heart and vascular systems

Multiple in vitro model systems are currently available to evaluate structure and function relationships in the cardiovascular system as well as the system's response to injury. As the level of molecular sophistication continues to advance, so does the level of complexity of the analysis. One of the most daunting tasks faced by researchers interested in studying cardiovascular function and injury is the selection of the system or systems best suited to answer the particular question at hand. In order to successfully apply any given model system, the researcher must recognize the advantages and limitations in the system of choice. This review provides a listing of the historical and modern techniques used to study cardiovascular function and chemically-induced toxicity. With the growing number of new pharmaceuticals discovered each year, it is imperative to use experimental model systems that allow for identification of targets that participate in or mediate adverse outcomes. Clearly, in vitro analysis cannot replace in vivo experimentation, but the methods currently available allow for a reduction in the number of animals used for experimentation and a better understanding of the complexity associated with the injury response.