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.

Genetic Predisposition to High-Altitude Pulmonary Edema

Background: Exaggerated pulmonary arterial hypertension (PAH) is a hallmark of high-altitude pulmonary edema (HAPE). The objective of this study was therefore to investigate genetic predisposition to HAPE by analyzing PAH candidate genes in a HAPE-susceptible (HAPE-S) family and in unrelated HAPE-S mountaineers. Materials and Methods: Eight family members and 64 mountaineers were clinically and genetically assessed using a PAH-specific gene panel for 42 genes by next-generation sequencing. Results: Two otherwise healthy family members, who developed re-entry HAPE at 3640 m during childhood, carried a likely pathogenic missense mutation (c.1198T>G p.Cys400Gly) in the Janus Kinase 2 (JAK2) gene. One of them progressed to a mild form of PAH at the age of 23 years. In two of the 64 HAPE-S mountaineers likely pathogenic variants have been detected, one missense mutation in the Cytochrome P1B1 gene, and a deletion in the Histidine-Rich Glycoprotein (HRG) gene. Conclusions: This is the first study identifying an inherited missense mutation of a gene related to PAH in a family with re-entry HAPE showing a progression to borderline PAH in the index patient. Likely pathogenic variants in 3.1% of HAPE-S mountaineers suggest a genetic predisposition in some individuals that might be linked to PAH signaling pathways.

Network pharmacology-based prediction of active compounds and molecular targets in Yijin-Tang acting on hyperlipidaemia and atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

Yijin-Tang (YJT) is a traditional prescription for the treatment of hyperlipidaemia, atherosclerosis and other ailments related to dampness phlegm, a typical pathological symptom of abnormal body fluid metabolism in Traditional Korean Medicine. However, a holistic network pharmacology approach to understanding the therapeutic mechanisms underlying hyperlipidaemia and atherosclerosis has not been pursued.

AIM OF THE STUDY

To examine the network pharmacological potential effects of YJT on hyperlipidaemia and atherosclerosis, we analysed components, performed target prediction and network analysis, and investigated interacting pathways using a network pharmacology approach.

MATERIALS AND METHODS

Information on compounds in herbal medicines was obtained from public databases, and oral bioavailability and drug-likeness was screened using absorption, distribution, metabolism, and excretion (ADME) criteria. Correlations between compounds and genes were linked using the STITCH database, and genes related to hyperlipidaemia and atherosclerosis were gathered using the GeneCards database. Human genes were identified and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULTS

Network analysis identified 447 compounds in five herbal medicines that were subjected to ADME screening, and 21 compounds and 57 genes formed the main pathways linked to hyperlipidaemia and atherosclerosis. Among them, 10 compounds (naringenin, nobiletin, hesperidin, galangin, glycyrrhizin, homogentisic acid, stigmasterol, 6-gingerol, quercetin and glabridin) were linked to more than four genes, and are bioactive compounds and key chemicals. Core genes in this network were CASP3, CYP1A1, CYP1A2, MMP2 and MMP9. The compound-target gene network revealed close interactions between multiple components and multiple targets, and facilitates a better understanding of the potential therapeutic effects of YJT.

CONCLUSIONS

Pharmacological network analysis can help to explain the potential effects of YJT for treating dampness phlegm-related diseases such as hyperlipidaemia and atherosclerosis.

Tumor Necrosis Factor Related Apoptosis Inducing Ligand (Trail) in endothelial response to biomechanical and biochemical stresses in arteries

Shear stress is determined by three physical components described in a famous triad: blood flow, blood viscosity and vessel geometry. Through the direct action on endothelium, shear stress is able to radically interfere with endothelial properties and the physiology of the vascular wall. Endothelial cells (ECs) have also to sustain biochemical stresses represented by chemokines, growth factors, cytokines, complement, hormones, nitric oxide (NO), oxygen and reactive oxygen species (ROS). Many growth factors, cytokines, chemokines, hormones, and chemical substances, like NO, act and regulate endothelium functions and homeostasis. Among these cytokines Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL) has been assigned a regulatory role in ECs physiology and physiopathology. Thus, the aim of this review is to provide a general overview of the endothelial response pathways after different types of biomechanical and biochemical stress in in vitro models and to analyze the crucial role of TRAIL under pathological conditions of the cardiocirculatory system like atherosclerosis, coronary artery disease, and diabetes.

A new concept of endometriosis and adenomyosis: tissue injury and repair (TIAR)

Pelvic endometriosis, deeply infiltrating endometriosis and uterine adenomyosis share a common pathophysiology and may be integrated into the physiological mechanism and new nosological concept of 'tissue injury and repair' (TIAR) and may, in this context, just represent the extreme of a basically physiological, estrogen-related mechanism that is pathologically exaggerated in an extremely estrogen-sensitive reproductive organ. The acronym TIAR describes a fundamental and apparently ubiquitous biological system that becomes operative in mesenchymal tissues following tissue injury and, upon activation, results in the local production of estradiol. Endometriosis and adenomyosis are caused by trauma. In the spontaneously developing disease, chronic uterine peristaltic activity or phases of hyperperistalsis induce, at the endometrial-myometrial interface near the fundo-cornual raphe, microtraumatisations, with activation of the TIAR mechanism. With ongoing traumatisations, such sites of inflammation might accumulate and the increasingly produced estrogens interfere in a paracrine fashion with ovarian control over uterine peristaltic activity, resulting in permanent hyperperistalsis and a self-perpetuation of the disease process. Overt autotraumatisation of the uterus with dislocation of fragments of basal endometrium into the peritoneal cavity and infiltration of basal endometrium into the depth of the myometrial wall ensues. In most cases of endometriosis/adenomyosis a causal event early in the reproductive period of life must be postulated, rapidly leading to archimetral hyperestrogenism and uterine hyperperistalsis. In late premenopausal adenomyosis such an event might not have occurred. However, as indicated by the high prevalence of the disease, it appears to be unavoidable that, with time, chronic normoperistalsis throughout the reproductive period of life accumulates to the same extent of microtraumatisation. With activation of the TIAR mechanism followed by chronic inflammation and infiltrative growth, endometriosis/adenomyosis of the younger woman and premenopausal adenomyosis share in principal the same pathophysiology.

Perspective on CFD studies of coronary artery disease lesions and hemodynamics: a review

Coronary artery disease (CAD) is the most common cardiovascular disease. Early diagnosis of CAD's physiological significance is of utmost importance for guiding individualized risk-tailored treatment strategies. In this paper, we first review the state-of-the-art clinical diagnostic indices to quantify the severity of CAD and the associated invasive and noninvasive imaging technologies in order to quantify the anatomical parameters of diameter stenosis, area stenosis, and hemodynamic indices of coronary flow reserve and fractional flow reserve. With the development of computational technologies and CFD methods, tremendous progress has been made in applying image-based CFD simulation techniques to elucidate the effects of hemodynamics in vascular pathophysiology toward the initialization and progression of CAD. So then, we review the advancements of CFD technologies in patient-specific modeling, involving the development of geometry reconstruction, boundary conditions, and fluid-structure interaction. Next, we review the applications of CFD to stenotic sites, in order to compute their hemodynamic parameters and study the relationship between the hemodynamic conditions and the clinical indices, to thereby assess the amount of viable myocardium and candidacy for percutaneous coronary intervention. Finally, we review the strengths and limitations of current researches of applying CFD to CAD studies.

Elevated blood pressure in cytochrome P4501A1 knockout mice is associated with reduced vasodilation to omega-3 polyunsaturated fatty acids

In vitro cytochrome P4501A1 (CYP1A1) metabolizes omega-3 polyunsaturated fatty acids (n-3 PUFAs); eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), primarily to 17,18-epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP), respectively. These metabolites have been shown to mediate vasodilation via increases in nitric oxide (NO) and activation of potassium channels. We hypothesized that genetic deletion of CYP1A1 would reduce vasodilatory responses to n-3 PUFAs, but not the metabolites, and increase blood pressure (BP) due to decreases in NO. We assessed BP by radiotelemetry in CYP1A1 wildtype (WT) and knockout (KO) mice±NO synthase (NOS) inhibitor. We also assessed vasodilation to acetylcholine (ACh), EPA, DHA, 17,18-EEQ and 19,20-EDP in aorta and mesenteric arterioles. Further, we assessed vasodilation to an NO donor and to DHA±inhibitors of potassium channels. CYP1A1 KO mice were hypertensive, compared to WT, (mean BP in mmHg, WT 103±1, KO 116±1, n=5/genotype, p<0.05), and exhibited a reduced heart rate (beats per minute, WT 575±5; KO 530±7; p<0.05). However, BP responses to NOS inhibition and vasorelaxation responses to ACh and an NO donor were normal in CYP1A1 KO mice, suggesting that NO bioavailability was not reduced. In contrast, CYP1A1 KO mice exhibited significantly attenuated vasorelaxation responses to EPA and DHA in both the aorta and mesenteric arterioles, but normal vasorelaxation responses to the CYP1A1 metabolites, 17,18-EEQ and 19,20-EDP, and normal responses to potassium channel inhibition. Taken together these data suggest that CYP1A1 metabolizes n-3 PUFAs to vasodilators in vivo and the loss of these vasodilators may lead to increases in BP.

Immediate early inflammatory gene responses of human umbilical vein endothelial cells to hemorrhagic venom

OBJECTIVE AND DESIGN

This report describes a focused immediate early gene response by human umbilical vein endothelial cells (HUVEC) to Echis carinatus snake venom.

MATERIALS OR SUBJECTS

Primary cultures of HUVEC were used to assess acute inflammatory gene responses.

TREATMENTS

Crude E. carinatus venom (2.5 µg/ml) was used to stimulate HUVEC.

RESULTS

HUVEC stimulated for 3 h with E. carinatus venom showed a focused response to the venom, with significant increases in metallothionein (e.g., MT1H, MT2A, MT1X) and cytochrome P450 (e.g., CYP1A1, CYP1B1) gene expressions compared to non-stimulated controls. Several other genes involved in cell growth and matrix attachment were repressed [e.g., thrombospondin 1 (THBS1), connective tissue growth factor (CTGF)].

CONCLUSIONS

These data suggest that acute vascular injury induced by hemorrhagic snake venom initiates an anti-oxidant response primarily involving metallothioneins.

Effect of cytochrome P450 polymorphism on arachidonic acid metabolism and their impact on cardiovascular diseases

Cardiovascular diseases (CVDs) remain the leading cause of death in the developed countries. Taking into account the mounting evidence about the role of cytochrome P450 (CYP) enzymes in cardiovascular physiology, CYP polymorphisms can be considered one of the major determinants of individual susceptibility to CVDs. One of the important physiological roles of CYP enzymes is the metabolism of arachidonic acid. CYP epoxygenases such as CYP1A2, CYP2C, and CYP2J2 metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs) which generally possess vasodilating, anti-inflammatory, anti-apoptotic, anti-thrombotic, natriuretic, and cardioprotective effects. Therefore, genetic polymorphisms causing lower activity of these enzymes are generally associated with an increased risk of several CVDs such as hypertension and coronary artery disease. EETs are further metabolized by soluble epoxide hydrolase (sEH) to the less biologically active dihydroxyeicosatrienoic acids (DHETs). Therefore, sEH polymorphism has also been shown to affect arachidonic acid metabolism and to be associated with CVDs. On the other hand, CYP omega-hydroxylases such as CYP4A11 and CYP4F2 metabolize arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE) which has both vasoconstricting and natriuretic effects. Genetic polymorphisms causing lower activity of these enzymes are generally associated with higher risk of hypertension. Nevertheless, some studies have denied the association between polymorphisms in the arachidonic acid pathway and CVDs. Therefore, more research is needed to confirm this association and to better understand the pathophysiologic mechanisms behind it.