19-Hydroxyeicosatetraenoic acid and isoniazid protect against angiotensin II-induced cardiac hypertrophy

Changes in cardiovascular arachidonic acid metabolism in experimental models of menopause and implications on postmenopausal cardiac hypertrophy

Menopause is a normal stage in the human female aging process characterized by the cessation of menstruation and the ovarian production of estrogen and progesterone hormones. Menopause is associated with an increased risk of several different diseases. Cardiovascular diseases are generally less common in females than in age-matched males. However, this female advantage is lost after menopause. Cardiac hypertrophy is a disease characterized by increased cardiac size that develops as a response to chronic overload or stress. Similar to other cardiovascular diseases, the risk of cardiac hypertrophy significantly increases after menopause. However, the exact underlying mechanisms are not yet fully elucidated. Several studies have shown that surgical or chemical induction of menopause in experimental animals is associated with cardiac hypertrophy, or aggravates cardiac hypertrophy induced by other stressors. Arachidonic acid (AA) released from the myocardial phospholipids is metabolized by cardiac cytochrome P450 (CYP), cyclooxygenase (COX), and lipoxygenase (LOX) enzymes to produce several eicosanoids. AA-metabolizing enzymes and their respective metabolites play an important role in the pathogenesis of cardiac hypertrophy. Menopause is associated with changes in the cardiovascular levels of CYP, COX, and LOX enzymes and the levels of their metabolites. It is possible that these changes might play a role in the increased risk of cardiac hypertrophy after menopause.

16R-HETE and 16S-HETE alter human cytochrome P450 1B1 enzyme activity probably through an allosteric mechanism

Cytochrome P450 1B1 (CYP1B1) has been widely associated with the development of cardiac pathologies due to its ability to produce cardiotoxic metabolites like midchain hydroxyeicosatetraenoic acids (HETEs) from arachidonic acid (AA) through an allylic oxidation reaction. 16-HETE is a subterminal HETE that is also produced by CYP-mediated AA metabolism. 19-HETE is another subterminal HETE that was found to inhibit CYP1B1 activity, lower midchain HETEs, and have cardioprotective effects. However, the effect of 16-HETE enantiomers on CYP1B1 has not yet been investigated. We hypothesized that 16(R/S)-HETE could alter the activity of CYP1B1 and other CYP enzymes. Therefore, this study was carried out to investigate the modulatory effect of 16-HETE enantiomers on CYP1B1 enzyme activity, and to examine the mechanisms by which they exert these modulatory effects. To investigate whether these effects are specific to CYP1B1, we also investigated 16-HETE modulatory effects on CYP1A2. Our results showed that 16-HETE enantiomers significantly increased CYP1B1 activity in RL-14 cells, recombinant human CYP1B1, and human liver microsomes, as seen by the significant increase in 7-ethoxyresorufin deethylation rate. On the contrary, 16-HETE enantiomers significantly inhibited CYP1A2 catalytic activity mediated by the recombinant human CYP1A2 and human liver microsomes. 16R-HETE showed stronger effects than 16S-HETE. The sigmoidal binding mode of the enzyme kinetics data demonstrated that CYP1B1 activation and CYP1A2 inhibition occurred through allosteric regulation. In conclusion, our study provides the first evidence that 16R-HETE and 16S-HETE increase CYP1B1 catalytic activity through an allosteric mechanism.

Enantioselectivity in some physiological and pathophysiological roles of hydroxyeicosatetraenoic acids

The phenomenon of chirality has been shown to greatly impact drug activities and effects. Different enantiomers may exhibit different effects in a certain biological condition or disease state. Cytochrome P450 (CYP) enzymes metabolize arachidonic acid (AA) into a large variety of metabolites with a wide range of activities. Hydroxylation of AA by CYP hydroxylases produces hydroxyeicosatetraenoic acids (HETEs), which are classified into mid-chain (5, 8, 9, 11, 12, and 15-HETE), subterminal (16-, 17-, 18- and 19-HETE) and terminal (20-HETE) HETEs. Except for 20-HETE, these metabolites exist as a racemic mixture of R and S enantiomers in the physiological system. The two enantiomers could have different degrees of activity or sometimes opposing effects. In this review article, we aimed to discuss the role of mid-chain and subterminal HETEs in different organs, importantly the heart and the kidneys. Moreover, we summarized their effects in some conditions such as neutrophil migration, inflammation, angiogenesis, and tumorigenesis, with a focus on the reported enantiospecific effects. We also reported some studies using genetically modified models to investigate the roles of HETEs in different conditions.

Sex- and enantiospecific differences in the formation rate of hydroxyeicosatetraenoic acids in rat organs

Hydroxyeicosatetraenoic acids (HETEs) are hydroxylated arachidonic acid (AA) metabolites that are classified into midchain, subterminal, and terminal HETEs. Hydroxylation results in the formation of R and S enantiomers for each HETE, except for 20-HETE. HETEs have multiple physiological and pathological effects. Several studies have demonstrated sex-specific differences in AA metabolism in different organs. In this study, microsomes from the heart, liver, kidney, lung, intestine, and brain of adult male and female Sprague-Dawley rats were isolated and incubated with AA. Thereafter, the enantiomers of all HETEs were analyzed by liquid chromatography-tandem mass spectrometry. We found significant sex- and enantiospecific differences in the formation levels of different HETEs in all organs. The majority of HETEs, especially midchain HETEs and 20-HETE, showed significantly higher formation rates in male organs. In the liver, the R enantiomer of several HETEs showed a higher formation rate than the corresponding S enantiomer (e.g., 8-, 9-, and 16-HETE). On the other hand, the brain and small intestine demonstrated a higher abundance of the S enantiomer. 19(S)-HETE was more abundant than 19(R)-HETE in all organs except the kidney. Elucidating sex-specific differences in HETE levels provides interesting insights into their physiological and pathophysiological roles and their possible implications for different diseases.

Polyunsaturated Fatty Acids: Conversion to Lipid Mediators, Roles in Inflammatory Diseases and Dietary Sources

Polyunsaturated fatty acids (PUFAs) are important components of the diet of mammals. Their role was first established when the essential fatty acids (EFAs) linoleic acid and α-linolenic acid were discovered nearly a century ago. However, most of the biochemical and physiological actions of PUFAs rely on their conversion to 20C or 22C acids and subsequent metabolism to lipid mediators. As a generalisation, lipid mediators formed from n-6 PUFAs are pro-inflammatory while those from n-3 PUFAs are anti-inflammatory or neutral. Apart from the actions of the classic eicosanoids or docosanoids, many newly discovered compounds are described as Specialised Pro-resolving Mediators (SPMs) which have been proposed to have a role in resolving inflammatory conditions such as infections and preventing them from becoming chronic. In addition, a large group of molecules, termed isoprostanes, can be generated by free radical reactions and these too have powerful properties towards inflammation. The ultimate source of n-3 and n-6 PUFAs are photosynthetic organisms which contain Δ-12 and Δ-15 desaturases, which are almost exclusively absent from animals. Moreover, the EFAs consumed from plant food are in competition with each other for conversion to lipid mediators. Thus, the relative amounts of n-3 and n-6 PUFAs in the diet are important. Furthermore, the conversion of the EFAs to 20C and 22C PUFAs in mammals is rather poor. Thus, there has been much interest recently in the use of algae, many of which make substantial quantities of long-chain PUFAs or in manipulating oil crops to make such acids. This is especially important because fish oils, which are their main source in human diets, are becoming limited. In this review, the metabolic conversion of PUFAs into different lipid mediators is described. Then, the biological roles and molecular mechanisms of such mediators in inflammatory diseases are outlined. Finally, natural sources of PUFAs (including 20 or 22 carbon compounds) are detailed, as well as recent efforts to increase their production.

Effect of inflammation on cytochrome P450-mediated arachidonic acid metabolism and the consequences on cardiac hypertrophy

The incidence of heart failure (HF) is generally preceded by cardiac hypertrophy (CH), which is the enlargement of cardiac myocytes in response to stress. During CH, the metabolism of arachidonic acid (AA), which is present in the cell membrane phospholipids, is modulated. Metabolism of AA gives rise to hydroxyeicosatetraenoic acids (HETEs) and epoxyeicosatrienoic acids (EETs) via cytochrome P450 (CYP) ω-hydroxylases and CYP epoxygenases, respectively. A plethora of studies demonstrated the involvement of CYP-mediated AA metabolites in the pathogenesis of CH. Also, inflammation is known to be a characteristic hallmark of CH. In this review, our aim is to highlight the impact of inflammation on CYP-derived AA metabolites and CH. Inflammation is shown to modulate the expression of various CYP ω-hydroxylases and CYP epoxygenases and their respective metabolites in the heart. In general, HETEs such as 20-HETE and mid-chain HETEs are pro-inflammatory, while EETs are characterized by their anti-inflammatory and cardioprotective properties. Several mechanisms are implicated in inflammation-induced CH, including the modulation of NF-κB and MAPK. This review demonstrated the inflammatory modulation of cardiac CYPs and their metabolites in the context of CH and the anti-inflammatory strategies that can be employed in the treatment of CH and HF.

Anti-obesity effect of Auricularia heimuer fruiting body alcohol extraction on obese mice and crucial metabolite pathway analysis by liquid chromatography-tandem mass spectrometry

In recent years, the increasing obese and overweight population has become a worldwide public health problem, as there is no effective medication to control obesity. Auricularia heimuer is rich in active substances that have potential biologically active functions. The anti-obesity effect and mechanism of Auricularia heimuer fruiting body alcohol extraction (AHA, 150-600 mg/kg·bw) was investigated in obese mice by assessing changes in endogenous liver metabolites using a liquid chromatography-tandem mass spectrometry approach. The aim of this study was to identify an effective food to control human obesity. AHA of 600 mg/kg·bw (HC) significantly decreased body weight and improved serum biochemistry indices. Sixty-eight liver metabolites were identified and significantly separated among the normal, high-fat diet (HFD), and HC groups. Moreover, the metabolic analysis revealed that HC significantly regulated specific metabolites in mice including amino acids, lipids, and carbohydrate compounds. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that HC was significantly involved in different metabolite pathways including arachidonic acid metabolism, galactose metabolism, carbohydrate digestion and absorption, linoleic acid metabolism, and starch and sucrose metabolism. Eight weeks after supplementing with HC, major metabolites in related pathways that were disrupted by an HFD were restored to normal levels, suggesting that HC had anti-obesity activity.

Sex differences in eicosanoid formation and metabolism: A possible mediator of sex discrepancies in cardiovascular diseases

Arachidonic acid is metabolized by cyclooxygenase, lipoxygenase, and cytochrome P450 enzymes to produce prostaglandins, leukotrienes, epoxyeicosatrienoic acids (EETs), and hydroxyeicosatetraenoic acids (HETEs), along with other eicosanoids. Eicosanoids have important physiological and pathological roles in the body, including the cardiovascular system. Evidence from several experimental and clinical studies indicates differences in eicosanoid levels, as well as in the activity or expression levels of their synthesizing and metabolizing enzymes between males and females. In addition, there is a clear state of gender specificity in cardiovascular diseases (CVD), which tend to be more common in men compared to women, and their risk increases significantly in postmenopausal women compared to younger women. This could be largely attributed to sex hormones, as androgens exert detrimental effects on the heart and blood vessels, whereas estrogen exhibits cardioprotective effects. Many of androgen and estrogen effects on the cardiovascular system are mediated by eicosanoids. For example, androgens increase the levels of cardiotoxic eicosanoids like 20-HETE, while estrogens increase the levels of cardioprotective EETs. Thus, sex differences in eicosanoid levels in the cardiovascular system could be an important underlying mechanism for the different effects of sex hormones and the differences in CVD between males and females. Understanding the role of eicosanoids in these differences can help improve the management of CVD.

The Functions of Cytochrome P450 ω-hydroxylases and the Associated Eicosanoids in Inflammation-Related Diseases

The cytochrome P450 (CYP) ω-hydroxylases are a subfamily of CYP enzymes. While CYPs are the main metabolic enzymes that mediate the oxidation reactions of many endogenous and exogenous compounds in the human body, CYP ω-hydroxylases mediate the metabolism of multiple fatty acids and their metabolites via the addition of a hydroxyl group to the ω- or (ω-1)-C atom of the substrates. The substrates of CYP ω-hydroxylases include but not limited to arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, epoxyeicosatrienoic acids, leukotrienes, and prostaglandins. The CYP ω-hydroxylases-mediated metabolites, such as 20-hyroxyleicosatrienoic acid (20-HETE), 19-HETE, 20-hydroxyl leukotriene B4 (20-OH-LTB₄), and many ω-hydroxylated prostaglandins, have pleiotropic effects in inflammation and many inflammation-associated diseases. Here we reviewed the classification, tissue distribution of CYP ω-hydroxylases and the role of their hydroxylated metabolites in inflammation-associated diseases. We described up-regulation of CYP ω-hydroxylases may be a pathogenic mechanism of many inflammation-associated diseases and thus CYP ω-hydroxylases may be a therapeutic target for these diseases. CYP ω-hydroxylases-mediated eicosanods play important roles in inflammation as pro-inflammatory or anti-inflammatory mediators, participating in the process stimulated by cytokines and/or the process stimulating the production of multiple cytokines. However, most previous studies focused on 20-HETE,and further studies are needed for the function and mechanisms of other CYP ω-hydroxylases-mediated eicosanoids. We believe that our studies of CYP ω-hydroxylases and their associated eicosanoids will advance the translational and clinal use of CYP ω-hydroxylases inhibitors and activators in many diseases.

Unraveling the Role of 12- and 20- HETE in Cardiac Pathophysiology: G-Protein-Coupled Receptors, Pharmacological Inhibitors, and Transgenic Approaches

ABSTRACT

Arachidonic acid-derived lipid mediators play crucial roles in the development and progression of cardiovascular diseases. Eicosanoid metabolites generated by lipoxygenases and cytochrome P450 enzymes produce several classes of molecules, including the epoxyeicosatrienoic acid (EET) and hydroxyeicosatetraenoic acids (HETE) family of bioactive lipids. In general, the cardioprotective effects of EETs have been documented across a number of cardiac diseases. In contrast, members of the HETE family have been shown to contribute to the pathogenesis of ischemic cardiac disease, maladaptive cardiac hypertrophy, and heart failure. The net effect of 12(S)- and 20-HETE depends upon the relative amounts generated, ratio of HETEs:EETs produced, timing of synthesis, as well as cellular and subcellular mechanisms activated by each respective metabolite. HETEs are synthesized by and affect multiple cell types within the myocardium. Moreover, cytochrome P450-derived and lipoxygenase- derived metabolites have been shown to directly influence cardiac myocyte growth and the regulation of cardiac fibroblasts. The mechanistic data uncovered thus far have employed the use of enzyme inhibitors, HETE antagonists, and the genetic manipulation of lipid-producing enzymes and their respective receptors, all of which influence a complex network of outcomes that complicate data interpretation. This review will summarize and integrate recent findings on the role of 12(S)-/20-HETE in cardiac diseases.

CYP1B1 as a therapeutic target in cardio-oncology

Cardiovascular complications have been frequently reported in cancer patients and survivors, mainly because of various cardiotoxic cancer treatments. Despite the known cardiovascular toxic effects of these treatments, they are still clinically used because of their effectiveness as anti-cancer agents. In this review, we discuss the growing body of evidence suggesting that inhibition of the cytochrome P450 1B1 enzyme (CYP1B1) can be a promising therapeutic strategy that has the potential to prevent cancer treatment-induced cardiovascular complications without reducing their anti-cancer effects. CYP1B1 is an extrahepatic enzyme that is expressed in cardiovascular tissues and overexpressed in different types of cancers. A growing body of evidence is demonstrating a detrimental role of CYP1B1 in both cardiovascular diseases and cancer, via perturbed metabolism of endogenous compounds, production of carcinogenic metabolites, DNA adduct formation, and generation of reactive oxygen species (ROS). Several chemotherapeutic agents have been shown to induce CYP1B1 in cardiovascular and cancer cells, possibly via activating the Aryl hydrocarbon Receptor (AhR), ROS generation, and inflammatory cytokines. Induction of CYP1B1 is detrimental in many ways. First, it can induce or exacerbate cancer treatment-induced cardiovascular complications. Second, it may lead to significant chemo/radio-resistance, undermining both the safety and effectiveness of cancer treatments. Therefore, numerous preclinical studies demonstrate that inhibition of CYP1B1 protects against chemotherapy-induced cardiotoxicity and prevents chemo- and radio-resistance. Most of these studies have utilized phytochemicals to inhibit CYP1B1. Since phytochemicals have multiple targets, future studies are needed to discern the specific contribution of CYP1B1 to the cardioprotective and chemo/radio-sensitizing effects of these phytochemicals.

Targeting arachidonic acid-related metabolites in COVID-19 patients: potential use of drug-loaded nanoparticles

In March 2020, The World Health Organization (WHO) has declared that the coronavirus disease 2019 (COVID-19) is characterized as a global pandemic. As of September 2020, infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to 213 countries and territories around the world, affected more than 31.5 million people, and caused more than 970,000 deaths worldwide. Although COVID-19 is a respiratory illness that mainly targets the lungs, it is currently well established that it is a multifactorial disease that affects other extra-pulmonary systems and strongly associated with a detrimental inflammatory response. Evidence has shown that SARS-CoV-2 causes perturbation in the arachidonic acid (AA) metabolic pathways; this disruption could lead to an imbalance between the pro-inflammatory metabolites of AA including mid-chain HETEs and terminal HETE (20-HETE) and the anti-inflammatory metabolites such as EETs and subterminal HETEs. Therefore, we propose novel therapeutic strategies to modulate the level of endogenous anti-inflammatory metabolites of AA and induce the patient's endogenous resolution mechanisms that will ameliorate the virus-associated systemic inflammation and enhance the primary outcomes in COVID-19 patients. Also, we propose that using nanoencapsulation of AA and its associated metabolites will contribute to the development of safer and more efficacious treatments for the management of COVID-19.

Itaconate prevents abdominal aortic aneurysm formation through inhibiting inflammation via activation of Nrf2

BACKGROUND

Identifying effective drugs to suppress vascular inflammation is a promising strategy to delay the progression of abdominal aortic aneurysm (AAA). Itaconate has a vital role in regulating inflammatory activation in various inflammatory diseases. However, the role of itaconate in the progression of AAA is unknown. In this study, we explored the inhibitory effect of itaconate on AAA formation and its underlying mechanisms.

METHODS

Quantitative PCR, western blotting and immunohistochemistry were used to determine Irg1 and downstream Nrf2 expression in human and mouse AAA samples. Liquid chromatograph-mass spectrometry (LC-MS) analysis was performed to measure the abundance of itaconate. OI treatment and Irg1 knockdown were performed to study the role of OI in AAA formation. Nrf2 intervention in vivo was performed to detect the critical role of Nrf2 in the beneficial effect of OI on AAA.

FINDINGS

We found that itaconate suppressed the formation of angiotensin II (Ang II)-induced AAA in apolipoprotein E-deficient (Apoe^-/-) mice, while Irg1 deficiency exerted the opposite effect. Mechanistically, itaconate inhibited vascular inflammation by enabling Nrf2 to function as a transcriptional repressor of downstream inflammatory genes via alkylation of Keap1. Moreover, Nrf2 deficiency significantly aggravated inflammatory factor expression and promoted AAA formation. In addition, Keap1 overexpression significantly promoted Ang II-induced AAA formation, which was inhibited by itaconate.

INTERPRETATION

Itaconate inhibited AAA formation by suppressing vascular inflammation, and therapeutic approaches to increase itaconate are potentially beneficial for preventing AAA formation.

FUNDING

National Natural Science Foundations of China and Guangzhou regenerative medicine and Health Laboratory of Guangdong.

Bioactive Lipid Signaling in Cardiovascular Disease, Development, and Regeneration

Cardiovascular disease (CVD) remains a leading cause of death globally. Understanding and characterizing the biochemical context of the cardiovascular system in health and disease is a necessary preliminary step for developing novel therapeutic strategies aimed at restoring cardiovascular function. Bioactive lipids are a class of dietary-dependent, chemically heterogeneous lipids with potent biological signaling functions. They have been intensively studied for their roles in immunity, inflammation, and reproduction, among others. Recent advances in liquid chromatography-mass spectrometry techniques have revealed a staggering number of novel bioactive lipids, most of them unknown or very poorly characterized in a biological context. Some of these new bioactive lipids play important roles in cardiovascular biology, including development, inflammation, regeneration, stem cell differentiation, and regulation of cell proliferation. Identifying the lipid signaling pathways underlying these effects and uncovering their novel biological functions could pave the way for new therapeutic strategies aimed at CVD and cardiovascular regeneration.

Dietary n-6 and n-3 PUFA alter the free oxylipin profile differently in male and female rat hearts

Oxylipins are bioactive lipid mediators synthesised from PUFA. The most well-known oxylipins are the eicosanoids derived from arachidonic acid (ARA), and many of them influence cardiac physiology in health and disease. Oxylipins are also formed from other n-3 and n-6 PUFA such as α-linolenic acid (ALA), EPA, DHA and linoleic acid (LA), but fundamental data on the heart oxylipin profile, and the effect of diet and sex on this profile, are lacking. Therefore, weanling female and male Sprague-Dawley rats were given American Institute of Nutrition (AIN)-93G-based diets modified in oil composition to provide higher levels of ALA, EPA, DHA, LA and LA + ALA, compared with control diets. After 6 weeks, free oxylipins in rat hearts were increased primarily by their precursor PUFA, except for EPA oxylipins, which were increased not only by dietary EPA but also by dietary ALA or DHA. Dietary DHA had a greater effect than ALA or EPA on reducing ARA oxylipins. An exception to the dietary n-3 PUFA-lowering effects on ARA oxylipins was observed for several ARA-derived PG metabolites that were higher in rats given EPA diets. Higher dietary LA increased LA oxylipins, but it had no effect on ARA oxylipins. Overall, heart oxylipins were higher in female rats, but this depended on dietary treatment: the female oxylipin:male oxylipin ratio was higher in rats provided the ALA compared with the DHA diet, with other diet groups having ratios in between. In conclusion, individual PUFA and sex have unique and interactive effects on the rat heart free oxylipin profile.

19-Hydroxyeicosatetraenoic acid analogs: Antagonism of 20-hydroxyeicosatetraenoic acid-induced vascular sensitization and hypertension

19-Hydroxyeicosatetraenoic acid (19-HETE, 1), a metabolically and chemically labile cytochrome P450 eicosanoid, has diverse biological activities including antagonism of the vasoconstrictor 20-hydroxyeicosatetraenoic acid (20-HETE, 2). A SAR study was conducted to develop robust analogs of 1 with improved in vitro and in vivo efficacy. Analogs were screened in vitro for inhibition of 20-HETE-induced sensitization of rat renal preglomerular microvessels toward phenylephrine and demonstrated to normalize the blood pressure of male Cyp4a14(-/-) mice that display androgen-driven, 20-HETE-dependent hypertension.

Subterminal hydroxyeicosatetraenoic acids: Crucial lipid mediators in normal physiology and disease states

Cytochrome P450 (P450) enzymes are superfamily of monooxygenases that hold the utmost diversity of substrate structures and catalytic reaction forms amongst all other enzymes. P450 enzymes metabolize arachidonic acid (AA) to a wide array of biologically active lipid mediators. P450-mediated AA metabolites have a significant role in normal physiological and pathophysiological conditions, hence they could be promising therapeutic targets in different disease states. P450 monooxygenases mediate the (ω-n)-hydroxylation reactions, which involve the introduction of a hydroxyl group to the carbon skeleton of AA, forming subterminal hydroxyeicosatetraenoic acids (HETEs). In the current review, we specified different P450 isozymes implicated in the formation of subterminal HETEs in varied tissues. In addition, we focused on the role of subterminal HETEs namely 19-HETE, 16-HETE, 17-HETE and 18-HETE in different organs, importantly the kidneys, heart, liver and brain. Furthermore, we highlighted their role in hypertension, acute coronary syndrome, diabetic retinopathy, non-alcoholic fatty liver disease, ischemic stroke as well as inflammatory diseases. Since each member of subterminal HETEs exist as R and S enantiomer, we addressed the issue of stereoselectivity related to the formation and differential effects of these enantiomers. In conclusion, elucidation of different roles of subterminal HETEs in normal and disease states leads to identification of novel therapeutic targets and development of new therapeutic modalities in different disease states.

20-HETE in the regulation of vascular and cardiac function

20-HETE, the ω-hydroxylation product of arachidonic acid catalyzed by enzymes of the cytochrome P450 (CYP) 4A and 4F gene families, is a bioactive lipid mediator with potent effects on the vasculature including stimulation of smooth muscle cell contractility, migration and proliferation as well as activation of endothelial cell dysfunction and inflammation. Clinical studies have shown elevated levels of plasma and urinary 20-HETE in human diseases and conditions such as hypertension, obesity and metabolic syndrome, myocardial infarction, stroke, and chronic kidney diseases. Studies of polymorphic associations also suggest an important role for 20-HETE in hypertension, stroke and myocardial infarction. Animal models of increased 20-HETE production are hypertensive and are more susceptible to cardiovascular injury. The current review summarizes recent findings that focus on the role of 20-HETE in the regulation of vascular and cardiac function and its contribution to the pathology of vascular and cardiac diseases.

Serum polyunsaturated fatty acid metabolites as useful tool for screening potential biomarker of colorectal cancer

The biomarker identification of cancer is benefit for early detection and less invasion. Polyunsaturated fatty acid (PUFA) metabolite as inflammatory mediators can affect progression and treatment of cancer. In this work, the serum was collected from colorectal cancer patients and healthy volunteers, and then we tested the change of serum PUFA metabolites in both of them by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Of the 158 PUFA and their metabolites, we found that abnormal change of 2, 3-dinor-8-iso-PGF2α, 19-HETE and 12-keto-LTB4 from arachidonic acid were observed in colorectal cancer patients. Meanwhile, 9-HODE and 13-HODE from linoleic acid were significant lower in colorectal cancer patients. Our data suggested that some PUFA metabolites might be used as a potential biomarker of colorectal cancer, which might provide assistance in clinical diagnosis and treatment.

Sex-dependent alteration of cardiac cytochrome P450 gene expression by doxorubicin in C57Bl/6 mice

BACKGROUND

There is inconclusive evidence about the role of sex as a risk factor for doxorubicin (DOX)-induced cardiotoxicity. Recent experimental studies have shown that adult female rats are protected against DOX-induced cardiotoxicity. However, the mechanisms of this sexual dimorphism are not fully elucidated. We have previously demonstrated that DOX alters the expression of several cytochrome P450 (CYP) enzymes in the hearts of male rats. Nevertheless, the sex-dependent effect of DOX on the expression of CYP enzymes is still not known. Therefore, in the present study, we determined the effect of acute DOX exposure on the expression of CYP genes in the hearts of both male and female C57Bl/6 mice.

METHODS

Acute DOX cardiotoxicity was induced by a single intraperitoneal injection of 20 mg/kg DOX in male and female adult C57Bl/6 mice. Cardiac function was assessed 5 days after DOX exposure by trans-thoracic echocardiography. Mice were euthanized 1 day or 6 days after DOX or saline injection. Thereafter, the hearts were harvested and weighed. Heart sections were evaluated for pathological lesions. Total RNA was extracted and expression of natriuretic peptides, inflammatory and apoptotic markers, and CYP genes was measured by real-time PCR.

RESULTS

Adult female C57Bl/6 mice were protected from acute DOX-induced cardiotoxicity as they show milder pathological lesions, less inflammation, and faster recovery from DOX-induced apoptosis and DOX-mediated inhibition of beta-type natriuretic peptide. Acute DOX exposure altered the gene expression of multiple CYP genes in a sex-dependent manner. In 24 h, DOX exposure caused male-specific induction of Cyp1b1 and female-specific induction of Cyp2c29 and Cyp2e1.

CONCLUSIONS

Acute DOX exposure causes sex-dependent alteration of cardiac CYP gene expression. Since cardiac CYP enzymes metabolize several endogenous compounds to biologically active metabolites, sex-dependent alteration of CYP genes may play a role in the sexual dimorphism of acute DOX-induced cardiotoxicity.

Molecular mechanisms and cell signaling of 20-hydroxyeicosatetraenoic acid in vascular pathophysiology

Cytochrome P450s enzymes catalyze the metabolism of arachidonic acid to epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid and hydroxyeicosatetraeonic acid (HETEs). 20-HETE is a vasoconstrictor that depolarizes vascular smooth muscle cells by blocking K+ channels. EETs serve as endothelial derived hyperpolarizing factors. Inhibition of the formation of 20-HETE impairs the myogenic response and autoregulation of renal and cerebral blood flow. Changes in the formation of EETs and 20-HETE have been reported in hypertension and drugs that target these pathways alter blood pressure in animal models. Sequence variants in CYP4A11 and CYP4F2 that produce 20-HETE, UDP-glucuronosyl transferase involved in the biotransformation of 20-HETE and soluble epoxide hydrolase that inactivates EETs are associated with hypertension in human studies. 20-HETE contributes to the regulation of vascular hypertrophy, restenosis, angiogenesis and inflammation. It also promotes endothelial dysfunction and contributes to cerebral vasospasm and ischemia-reperfusion injury in the brain, kidney and heart. This review will focus on the role of 20-HETE in vascular dysfunction, inflammation, ischemic and hemorrhagic stroke and cardiac and renal ischemia reperfusion injury.