Venous Access: National Guideline and Registry Development (VANGUARD): Advancing Patient-Centered Venous Access Care Through the Development of a National Coordinated Registry Network.

There are over 8 million central venous access devices inserted each year, many in patients with chronic conditions who rely on central access for life-preserving therapies. Central venous access device-related complications can be life-threatening and add tens of billions of dollars to health care costs, while their incidence is most likely grossly mis- or underreported by medical institutions. In this communication, we review the challenges that impair retention, exchange, and analysis of data necessary for a meaningful understanding of critical events and outcomes in this clinical domain. The difficulty is not only with data extraction and harmonization from electronic health records, national surveillance systems, or other health information repositories where data might be stored. The problem is that reliable and appropriate data are not recorded, or falsely recorded, at least in part because policy, payment, penalties, proprietary concerns, and workflow burdens discourage completeness and accuracy. We provide a roadmap for the development of health care information systems and infrastructure that address these challenges, framed within the context of research studies that build a framework of standardized terminology, decision support, data capture, and information exchange necessary for the task. This roadmap is embedded in a broader Coordinated Registry Network Learning Community, and facilitated by the Medical Device Epidemiology Network, a Public-Private Partnership sponsored by the US Food and Drug Administration, with the scope of advancing methods, national and international infrastructure, and partnerships needed for the evaluation of medical devices throughout their total life cycle.

Interaction of RIPK1 and A20 modulates MAPK signaling in murine acetaminophen toxicity.

Acetaminophen (APAP)-induced liver necrosis is a form of regulated cell death (RCD) in which APAP activates the mitogen-activated protein kinases (MAPKs) and specifically the c-Jun-N-terminal kinase (JNK) pathway, leading to necrotic cell death. Previously, we have shown that receptor interacting protein kinase-1 (RIPK1) knockdown is also protective against APAP RCD upstream of JNK. However, whether the kinase or platform function of RIPK1 is involved in APAP RCD is not known. To answer this question, we used genetic mouse models of targeted hepatocyte RIPK1 knockout (RIPK1HepCKO) or kinase dead knock-in (RIPK1D138N) and adult hepatocyte specific knockout of the cytoprotective protein A20 (A20HepCKO), known to interact with RIPK1, to study its potential involvement in MAPK signaling. We observed no difference in injury between WT and RIPK1D138N mice post APAP. However, RIPK1HepCKO was protective. We found that RIPK1HepCKO mice had attenuated pJNK activation, while A20 was simultaneously upregulated. Conversely, A20HepCKO markedly worsened liver injury from APAP. Mechanistically, we observed a significant upregulation of apoptosis signal-regulating kinase 1 (ASK1) and increased JNK activation in A20HepCKO mice compared with littermate controls. We also demonstrated that A20 coimmunoprecipitated (co-IP) with both RIPK1 and ASK1, and that in the presence of RIPK1, there was less A20-ASK1 association than in its absence. We conclude that the kinase-independent platform function of RIPK1 is involved in APAP toxicity. Adult RIPK1HepCKO mice are protected against APAP by upregulating A20 and attenuating JNK signaling through ASK1, conversely, A20HepCKO worsens injury from APAP.

Cell Death in Liver Diseases: A Review.

Regulated cell death (RCD) is pivotal in directing the severity and outcome of liver injury. Hepatocyte cell death is a critical event in the progression of liver disease due to resultant inflammation leading to fibrosis. Apoptosis, necrosis, necroptosis, autophagy, and recently, pyroptosis and ferroptosis, have all been investigated in the pathogenesis of various liver diseases. These cell death subroutines display distinct features, while sharing many similar characteristics with considerable overlap and crosstalk. Multiple types of cell death modes can likely coexist, and the death of different liver cell populations may contribute to liver injury in each type of disease. This review addresses the known signaling cascades in each cell death pathway and its implications in liver disease. In this review, we describe the common findings in each disease model, as well as the controversies and the limitations of current data with a particular focus on cell death-related research in humans and in rodent models of alcoholic liver disease, non-alcoholic fatty liver disease and steatohepatitis (NASH/NAFLD), acetaminophen (APAP)-induced hepatotoxicity, autoimmune hepatitis, cholestatic liver disease, and viral hepatitis.

Drug-Induced Liver Injury: Cascade of Events Leading to Cell Death, Apoptosis or Necrosis.

Drug-induced liver injury (DILI) can broadly be divided into predictable and dose dependent such as acetaminophen (APAP) and unpredictable or idiosyncratic DILI (IDILI). Liver injury from drug hepatotoxicity (whether idiosyncratic or predictable) results in hepatocyte cell death and inflammation. The cascade of events leading to DILI and the cell death subroutine (apoptosis or necrosis) of the cell depend largely on the culprit drug. Direct toxins to hepatocytes likely induce oxidative organelle stress (such as endoplasmic reticulum (ER) and mitochondrial stress) leading to necrosis or apoptosis, while cell death in idiosyncratic DILI (IDILI) is usually the result of engagement of the innate and adaptive immune system (likely apoptotic), involving death receptors (DR). Here, we review the hepatocyte cell death pathways both in direct hepatotoxicity such as in APAP DILI as well as in IDILI. We examine the known signaling pathways in APAP toxicity, a model of necrotic liver cell death. We also explore what is known about the genetic basis of IDILI and the molecular pathways leading to immune activation and how these events can trigger hepatotoxicity and cell death.

Apolipoprotein A-I mimetic peptide 4F rescues pulmonary hypertension by inducing microRNA-193-3p.

BACKGROUND: Pulmonary arterial hypertension is a chronic lung disease associated with severe pulmonary vascular changes. A pathogenic role of oxidized lipids such as hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids is well established in vascular disease. Apolipoprotein A-I mimetic peptides, including 4F, have been reported to reduce levels of these oxidized lipids and improve vascular disease. However, the role of oxidized lipids in the progression of pulmonary arterial hypertension and the therapeutic action of 4F in pulmonary arterial hypertension are not well established. METHODS AND RESULTS: We studied 2 different rodent models of pulmonary hypertension (PH): a monocrotaline rat model and a hypoxia mouse model. Plasma levels of hydroxyeicosatetraenoic and hydroxyoctadecadienoic acids were significantly elevated in PH. 4F treatment reduced these levels and rescued preexisting PH in both models. MicroRNA analysis revealed that microRNA-193-3p (miR193) was significantly downregulated in the lung tissue and serum from both patients with pulmonary arterial hypertension and rodents with PH. In vivo miR193 overexpression in the lungs rescued preexisting PH and resulted in downregulation of lipoxygenases and insulin-like growth factor-1 receptor. 4F restored PH-induced miR193 expression via transcription factor retinoid X receptor α. CONCLUSIONS: These studies establish the importance of microRNAs as downstream effectors of an apolipoprotein A-I mimetic peptide in the rescue of PH and suggest that treatment with apolipoprotein A-I mimetic peptides or miR193 may have therapeutic value.

Cardiac vulnerability to ischemia/reperfusion injury drastically increases in late pregnancy.

Although the murine late pregnant (LP) heart is speculated to be a better functioning heart during physiological conditions, the susceptibility of LP hearts to I/R injury is still unknown. The aims of this study were to investigate the cardiac vulnerability of LP rodents to ischemia/reperfusion (I/R) injury and to explore its underlying mechanisms. In vivo female rat hearts [non-pregnant (NP) or LP] or ex vivo Langendorff-perfused mouse hearts were subjected to I/R. The infarct size was approximately fourfold larger in LP animals compared with NP both in vivo and ex vivo. The heart functional recovery was extremely poor in LP mice compared with NP (~10% recovery in LP vs. 80% recovery in NP at the end of reperfusion, P < 0.01). Interestingly, the poor functional recovery and the larger infarct size in LP were partially restored one day post-partum and almost fully restored 1 week post-partum to their corresponding NP levels. Mitochondrial respiratory function and the threshold for opening of the mitochondrial permeability transition pore were significantly lower in LP compared with NP when they both were subjected to myocardial I/R injury [Respiratory control ratio = 1.9 ± 0.1 vs. 4.0 ± 0.5 in NP, P < 0.05; calcium retention capacity (CRC) = 167 ± 10 vs. 233 ± 18 nmol/mg protein in NP, P < 0.01]. Cardiac reactive oxygen species (ROS) generation, as well mitochondrial superoxide production, was approximately twofold higher in LP compared with NP following I/R. The phosphorylation levels of Akt, ERK1/2, and STAT3, but not GSK3ß, were significantly reduced in the hearts from LP subjected to I/R. In conclusion, increased mitochondrial ROS generation, decreased CRC as well as impaired activation of Akt/ERK/STAT3 at reperfusion are the possible underlying mechanisms for higher vulnerability of LP hearts to I/R.

Intralipid, a clinically safe compound, protects the heart against ischemia-reperfusion injury more efficiently than cyclosporine-A.

BACKGROUND: We have recently shown that postischemic administration of intralipid protects the heart against ischemia-reperfusion injury. Here we compared the cardioprotective effects of intralipid with cyclosporine-A, a potent inhibitor of the mitochondrial permeability transition pore opening. METHODS: In vivo rat hearts or isolated Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion with intralipid (0.5%, 1% and 2% ex-vivo, and 20% in vivo), cyclosporine-A (0.2 µM, 0.8 µM, and 1.5 µM ex- vivo and 10 mg/kg in vivo), or vehicle. The hemodynamic function, infarct size, calcium retention capacity, mitochondrial superoxide production, and phosphorylation levels of protein kinase B (Akt)/glycogen synthase kinase-3ß (GSK-3ß) were measured. The values are mean ± SEM. RESULTS: Administration of intralipid at reperfusion significantly reduced myocardial infarct size compared with cyclosporine-A in vivo (infarct size/area at risk)%: 22.9 ± 2.5% vs. 35.2 ± 3.5%; P = 0.030, n = 7/group). Postischemic administration of intralipid at its optimal dose (1%) was more effective than cyclosporine-A (0.8 µM) in protecting the ex vivo heart against ischemia-reperfusion injury, as the rate pressure product at the end of reperfusion was significantly higher (mmHg · beats/min: 12,740 ± 675 [n = 7] vs. 9,203 ± 10,781 [n = 5], P = 0.024), and the infarct size was markedly smaller (17.3 ± 2.9 [n = 7] vs. 29.2 ± 2.7 [n = 5], P = 0.014). Intralipid was as efficient as cyclosporine-A in inhibiting the mitochondrial permeability transition pore opening (calcium retention capacity = 280 ± 8.2 vs. 260.3 ± 2.9 nmol/mg mitochondria protein in cyclosporine-A, P = 0.454, n = 6) and in reducing cardiac mitochondrial superoxide production. Unlike intralipid, which increased phosphorylation of Akt (6-fold) and GSK-3ß (5-fold), cyclosporine-A had no effect on the activation of these prosurvival kinases. CONCLUSIONS: Although intralipid inhibits the opening of the mitochondrial permeability transition pore as efficiently as cyclosporine-A, intralipid is more effective in reducing the infarct size and improving the cardiac functional recovery.

Estrogen rescues preexisting severe pulmonary hypertension in rats.

RATIONALE: Pulmonary hypertension (PH) is characterized by progressive increase in pulmonary artery pressure leading to right ventricular (RV) hypertrophy, RV failure, and death. Current treatments only temporarily reduce severity of the disease, and an ideal therapy is still lacking. OBJECTIVES: Estrogen pretreatment has been shown to attenuate development of PH. Because PH is not often diagnosed early, we examined if estrogen can rescue preexisting advanced PH. METHODS: PH was induced in male rats with monocrotaline (60 mg/kg). At Day 21, rats were either treated with 17-ß estradiol or estrogen (E2, 42.5 µg/kg/d), estrogen receptor-ß agonist (diarylpropionitrile, 850 µg/kg/d), or estrogen receptor α-agonist (4,4',4"-[4-Propyl-(1H)-pyrazole-1,3,5-triyl] trisphenol, 850 µg/kg/d) for 10 days or left untreated to develop RV failure. Serial echocardiography, cardiac catheterization, immunohistochemistry, Western blot, and real-time polymerase chain reaction were performed. MEASUREMENTS AND MAIN RESULTS: Estrogen therapy prevented progression of PH to RV failure and restored lung and RV structure and function. This restoration was maintained even after removal of estrogen at Day 30, resulting in 100% survival at Day 42. Estradiol treatment restored the loss of blood vessels in the lungs and RV. In the presence of angiogenesis inhibitor TNP-470 (30 mg/kg) or estrogen receptor-ß antagonist (PHTPP, 850 µg/kg/d), estrogen failed to rescue PH. Estrogen receptor-ß selective agonist was as effective as estrogen in rescuing PH. CONCLUSIONS: Estrogen rescues preexisting severe PH in rats by restoring lung and RV structure and function that are maintained even after removal of estrogen. Estrogen-induced rescue of PH is associated with stimulation of cardiopulmonary neoangiogenesis, suppression of inflammation, fibrosis, and RV hypertrophy. Furthermore, estrogen rescue is likely mediated through estrogen receptor-ß.

Developing minimum core data structure for the obesity devices Coordinated Registry Network (CRN).

Obesity continues to be a major public health issue, with more than two-thirds of adults in the USA categorized as overweight or obese. Bariatric surgery is effective and yields durable weight loss; however, few qualified candidates choose to undergo surgical treatment. Less-invasive alternatives to bariatric surgery are being developed to bridge the treatment gap. Recognizing the burden of conducting pivotal clinical trials and traditional post-approval studies for medical devices, the Food and Drug Administration (FDA) Center for Devices and Radiological Health has encouraged the development of real-world data content and quality that is sufficient to provide evidence for Total Product Life Cycle medical device evaluation. A key first step is to establish a minimum core data structure that provides a common lexicon for endoscopic obesity devices and its corresponding interoperable data elements. Such a structure would facilitate data capture across existing workflow with a 'coordinated registry network' capability. On July 29, 2016, a workshop entitled, 'GI Coordinated Registry Network: A Case for Obesity Devices' was held at the FDA White Oak Campus by the Medical Device Epidemiology Network public-private partnership and FDA to initiate the work of developing a common lexicon and core data elements in the metabolic device space, which marked the inauguration of the Gastrointestinal Coordinated Registry Network project. Several work groups were subsequently formed to address clinical issues, data quality issues, registry participation, and data sharing.

Autophagy impairment in liver CD11c+ cells promotes non-alcoholic fatty liver disease through production of IL-23.

There has been a global increase in rates of obesity with a parallel epidemic of non-alcoholic fatty liver disease (NAFLD). Autophagy is an essential mechanism involved in the degradation of cellular material and has an important function in the maintenance of liver homeostasis. Here, we explore the effect of Autophagy-related 5 (Atg5) deficiency in liver CD11c+ cells in mice fed HFD. When compared to control mice, Atg5-deficient CD11c+ mice exhibit increased glucose intolerance and decreased insulin sensitivity when fed HFD. This phenotype is associated with the development of NAFLD. We observe that IL-23 secretion is induced in hepatic CD11c+ myeloid cells following HFD feeding. We demonstrate that both therapeutic and preventative IL-23 blockade alleviates glucose intolerance, insulin resistance and protects against NAFLD development. This study provides insights into the function of autophagy and IL-23 production by hepatic CD11c+ cells in NAFLD pathogenesis and suggests potential therapeutic targets.

Phosphorylation of GSK-3ß mediates intralipid-induced cardioprotection against ischemia/reperfusion injury.

BACKGROUND: Intralipid (Sigma, St. Louis, MO), a brand name for the first safe fat emulsion for human use, has been shown to be cardioprotective. However, the mechanism of this protection is not known. The authors investigated the molecular mechanism(s) of Intralipid-induced cardioprotection against ischemia/reperfusion injury, particularly the role of glycogen synthase kinase-3ß (GSK-3ß) and mitochondrial permeability transition pore in this protective action. METHODS: In vivo rat hearts or isolated Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion with Intralipid (1% in ex vivo and one bolus of 20% in in vivo) or vehicle. The hemodynamic function, infarct size, threshold for the opening of mitochondrial permeability transition pore, and phosphorylation levels of protein kinase B (Akt)/extracellular signal regulating kinase (ERK)/GSK-3ß were measured. RESULTS: Administration of Intralipid at the onset of reperfusion resulted in approximately 70% reduction in infarct size in the in vivo rat model. Intralipid also significantly improved functional recovery of isolated Langendorff-perfused mouse hearts as the rate pressure product was increased from 2,999 ± 863 mmHg*beats/min in the control group to 13,676 ± 611 mmHg*beats/min (mean±SEM) and the infarct size was markedly smaller (18.3 ± 2.4% vs. 54.8 ± 2.9% in the control group, P < 0.01). The Intralipid-induced cardioprotection was fully abolished by LY294002, a specific inhibitor of PI3K, but only partially by PD98059, a specific ERK inhibitor. Intralipid also increased the phosphorylation levels of Akt/ERK1/glycogen synthase kinase-3ß by eightfold, threefold, and ninefold, respectively. The opening of mitochondrial permeability transition pore was inhibited by Intralipid because calcium retention capacity was higher in the Intralipid group (274.3 ± 8.4 nM/mg vs. 168.6 ± 9.6 nM/mg in the control group). CONCLUSIONS: Postischemic treatment with Intralipid inhibits the opening of mitochondiral permeability transition pore and protects the heart through glycogen synthase kinase-3ß via PI3K/Akt/ERK pathways.

Mechanisms of immune checkpoint inhibitor-mediated liver injury.

The immune checkpoints, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein-1/ligand-1 (PD-1/PD-L1) are vital contributors to immune regulation and tolerance. Recently immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy; however, they come with the cost of immune related adverse events involving multiple organs such as the liver. Due to its constant exposure to foreign antigens, the liver has evolved a high capacity for immune tolerance, therefore, blockade of the immune checkpoints can result in aberrant immune activation affecting the liver in up to 20% of patients depending on the agent(s) used and underlying factors. This type of hepatotoxicity is termed immune mediated liver injury from checkpoint inhibitors (ILICI) and is more common when CTLA4 and PD-1/PD-L1 are used in combination. The underlying mechanisms of this unique type of hepatotoxicity are not fully understood; however, the contribution of CD8+ cytotoxic T lymphocytes, various CD4+ T cells populations, cytokines, and the secondary activation of the innate immune system leading to liver injury have all been suggested. This review summarizes our current understanding of the underlying mechanisms of liver injury in immunotherapy using animal models of ILICI and available patient data from clinical studies.

Cell death in drug-induced liver injury.

Drug-induced liver injury (DILI) is an important cause of liver toxicity which can have varying clinical presentations, the most severe of which being acute liver failure. Hepatocyte death as a cause of drug toxicity is a feature of DILI. There are multiple cell death subroutines; some, like apoptosis, necroptosis, autophagy, and necrosis have been extensively studied, while others such as pyroptosis and ferroptosis have been more recently described. The mode of cell death in DILI depends on the culprit drug, as it largely dictates the mechanism and extent of injury. The main cell death subroutines in DILI are apoptosis and necrosis, with mitochondrial involvement being pivotal for the execution of both. A few drugs such as acetaminophen (APAP) can cause direct, dose-dependent toxicity, while the majority of drugs cause idiosyncratic DILI (IDILI). IDILI is an unpredictable form of liver injury that is not dose dependent, occurs in individuals with a genetic predisposition, and presents with variable latency. APAP-induced programmed necrosis has been extensively studied. However, the mechanisms and pathogenesis of cell death from drugs causing IDILI are harder to elucidate due to the complex and multifactorial nature of the disease. Cell death in IDILI is likely death receptor-mediated apoptosis and the result of an activated innate and adaptive immune system, compounded by other host factors such as genetics, gender, age, and capacity for immune tolerance. This chapter will review the different modes of cell death, namely apoptosis, necrosis, necroptosis, autophagy, pyroptosis, and ferroptosis and their pertinence to DILI.

Estrogen rescues heart failure through estrogen receptor Beta activation.

BACKGROUND: Recently, we showed that exogenous treatment with estrogen (E2) rescues pre-existing advanced heart failure (HF) in mice. Since most of the biological actions of E2 are mediated through the classical estrogen receptors alpha (ERα) and/or beta (ERß), and both these receptors are present in the heart, we examined the role of ERα and ERß in the rescue action of E2 against HF. METHODS: Severe HF was induced in male mice by transverse aortic constriction-induced pressure overload. Once the ejection fraction (EF) reached ~ 35%, mice were treated with selective agonists for ERα (PPT, 850 µg/kg/day), ERß (DPN, 850 µg/kg/day), or E2 (30 µg/kg/day) together with an ERß-antagonist (PHTPP, 850 µg/kg/day) for 10 days. RESULTS: EF of HF mice was significantly improved to 45.3 ± 2.1% with diarylpropionitrile (DPN) treatment, but not with PPT (31.1 ± 2.3%). E2 failed to rescue HF in the presence of PHTPP, as there was no significant improvement in the EF at the end of the 10-day treatment (32.5 ± 5.2%). The improvement of heart function in HF mice treated with ERß agonist DPN was also associated with reduced cardiac fibrosis and increased cardiac angiogenesis, while the ERα agonist PPT had no significant effect on either cardiac fibrosis or angiogenesis. Furthermore, DPN improved hemodynamic parameters in HF mice, whereas PPT had no significant effect. CONCLUSIONS: E2 treatment rescues pre-existing severe HF mainly through ERß. Rescue of HF by ERß activation is also associated with stimulation of cardiac angiogenesis, suppression of fibrosis, and restoration of hemodynamic parameters.

Severe pulmonary hypertension in aging female apolipoprotein E-deficient mice is rescued by estrogen replacement therapy.

BACKGROUND: Apolipoprotein E (ApoE) is a multifunctional protein, and its deficiency leads to the development of atherosclerosis in mice. Patients with pulmonary hypertension (PH) have reduced expression of ApoE in lung tissue. ApoE is known to inhibit endothelial and smooth muscle cell proliferation and has anti-inflammatory and anti-platelet aggregation properties. Young ApoE-deficient mice have been shown to develop PH on high fat diet. The combined role of female sex and aging in the development of PH has not been investigated before. Here, we investigated the development of PH in young and middle-aged (MA) female ApoE-deficient mice and explored the role of exogenous estrogen (E2) replacement therapy for the aging females. METHODS: Wild type (WT) and ApoE-deficient female mice (Young and MA) were injected with a single intraperitoneal dose of monocrotaline (MCT, 60 mg/kg). Some ApoE-deficient MA female mice that received MCT were also treated with subcutaneous E2 pellets (0.03 mg/kg/day) from day 21 to 30 after MCT injection. Direct cardiac catheterization was performed terminally to record right ventricular systolic pressure (RVSP). Right ventricular (RV), left ventricular (LV), and interventricular septum (IVS) were dissected and weighed. Lung sections were examined using trichrome and immunofluorescence staining. Western blot analyses of lung and RV lysates were performed. RESULTS: In WT female mice, the severity of PH was similar between young and MA mice as RVSP was not significantly different (RVSP = 38.2 ± 1.2 in young vs. 40.5 ± 8.3 mmHg in MA, p < 0.05). In ApoE-deficient mice, MA females developed significantly severe PH (RVSP = 63 ± 10 mmHg) compared to young females (RVSP; 36 ± 3 mmHg, p < 0.05 vs. MA female). ApoE-deficient MA females also developed more severe RV hypertrophy compared to young females (RV hypertrophy index (RV/[LV + IVS]) = 0.53 ± 0.06 vs. 0.33 ± 0.01, p < 0.05). ApoE-deficient MA female mice manifested increased peripheral pulmonary artery muscularization and pulmonary fibrosis. E2 treatment of MA female ApoE-deficient mice resulted in a significant decrease in RVSP, reversal of pulmonary vascular remodeling, and RV hypertrophy. In MA female ApoE-deficient mice with PH, only the expression of ERß in the lungs, but not in RV, was significantly downregulated, and it was restored by E2 treatment. The expression of ERα was not affected in either lungs or RV by PH. GPR30 was only detected in the RV, and it was not affected by PH in MA female ApoE-deficient mice. CONCLUSIONS: Our results suggest that only aging female ApoE-deficient but not WT mice develop severe PH compared to younger females. Exogenous estrogen therapy rescued PH and RV hypertrophy in aging female ApoE-deficient mice possibly through restoration of lung ERß.

The protective role of estrogen and estrogen receptors in cardiovascular disease and the controversial use of estrogen therapy.

Epidemiologic studies have previously suggested that premenopausal females have reduced incidence of cardiovascular disease (CVD) when compared to age-matched males, and the incidence and severity of CVD increases postmenopause. The lower incidence of cardiovascular disease in women during reproductive age is attributed at least in part to estrogen (E2). E2 binds to the traditional E2 receptors (ERs), estrogen receptor alpha (ERα), and estrogen receptor beta (ERß), as well as the more recently identified G-protein-coupled ER (GPR30), and can exert both genomic and non-genomic actions. This review summarizes the protective role of E2 and its receptors in the cardiovascular system and discusses its underlying mechanisms with an emphasis on oxidative stress, fibrosis, angiogenesis, and vascular function. This review also presents the sexual dimorphic role of ERs in modulating E2 action in cardiovascular disease. The controversies surrounding the clinical use of exogenous E2 as a therapeutic agent for cardiovascular disease in women due to the possible risks of thrombotic events, cancers, and arrhythmia are also discussed. Endogenous local E2 biosynthesis from the conversion of testosterone to E2 via aromatase enzyme offers a novel therapeutic paradigm. Targeting specific ERs in the cardiovascular system may result in novel and possibly safer therapeutic options for cardiovascular protection.

Rescue of Pressure Overload-Induced Heart Failure by Estrogen Therapy.

BACKGROUND: Estrogen pretreatment has been shown to attenuate the development of heart hypertrophy, but it is not known whether estrogen could also rescue heart failure (HF). Furthermore, the heart has all the machinery to locally biosynthesize estrogen via aromatase, but the role of local cardiac estrogen synthesis in HF has not yet been studied. Here we hypothesized that cardiac estrogen is reduced in HF and examined whether exogenous estrogen therapy can rescue HF. METHODS AND RESULTS: HF was induced by transaortic constriction in mice, and once mice reached an ejection fraction (EF) of ≈35%, they were treated with estrogen for 10 days. Cardiac structure and function, angiogenesis, and fibrosis were assessed, and estrogen was measured in plasma and in heart. Cardiac estrogen concentrations (6.18±1.12 pg/160 mg heart in HF versus 17.79±1.28 pg/mL in control) and aromatase transcripts (0.19±0.04, normalized to control, P<0.05) were significantly reduced in HF. Estrogen therapy increased cardiac estrogen 3-fold and restored aromatase transcripts. Estrogen also rescued HF by restoring ejection fraction to 53.1±1.3% (P<0.001) and improving cardiac hemodynamics both in male and female mice. Estrogen therapy stimulated angiogenesis as capillary density increased from 0.66±0.07 in HF to 2.83±0.14 (P<0.001, normalized to control) and reversed the fibrotic scarring observed in HF (45.5±2.8% in HF versus 5.3±1.0%, P<0.001). Stimulation of angiogenesis by estrogen seems to be one of the key mechanisms, since in the presence of an angiogenesis inhibitor estrogen failed to rescue HF (ejection fraction=29.3±2.1%, P<0.001 versus E2). CONCLUSIONS: Estrogen rescues pre-existing HF by restoring cardiac estrogen and aromatase, stimulating angiogenesis, and suppressing fibrosis.

Pregnancy is associated with decreased cardiac proteasome activity and oxidative stress in mice.

During pregnancy, the heart develops physiological hypertrophy. Proteasomal degradation has been shown to be altered in various models of pathological cardiac hypertrophy. Since the molecular signature of pregnancy-induced heart hypertrophy differs significantly from that of pathological heart hypertrophy, we investigated whether the cardiac proteasomal proteolytic pathway is affected by pregnancy in mice. We measured the proteasome activity, expression of proteasome subunits, ubiquitination levels and reactive oxygen production in the hearts of four groups of female mice: i) non pregnant (NP) at diestrus stage, ii) late pregnant (LP), iii) one day post-partum (PP1) and iv) 7 days post-partum (PP7). The activities of the 26 S proteasome subunits ß1 (caspase-like), and ß2 (trypsin-like) were significantly decreased in LP (ß1∶83.26 ± 1.96%; ß2∶74.74 ± 1.7%, normalized to NP) whereas ß5 (chymotrypsin-like) activity was not altered by pregnancy but significantly decreased 1 day post-partum. Interestingly, all three proteolytic activities of the proteasome were restored to normal levels 7 days post-partum. The decrease in proteasome activity in LP was not due to the surge of estrogen as estrogen treatment of ovariectomized mice did not alter the 26 S proteasome activity. The transcript and protein levels of RPN2 and RPT4 (subunits of 19 S), ß2 and α7 (subunits of 20 S) as well as PA28α and ß5i (protein only) were not significantly different among the four groups. High resolution confocal microscopy revealed that nuclear localization of both core (20S) and RPT4 in LP is increased ∼2-fold and is fully reversed in PP7. Pregnancy was also associated with decreased production of reactive oxygen species and ubiquitinated protein levels, while the de-ubiquitination activity was not altered by pregnancy or parturition. These results indicate that late pregnancy is associated with decreased ubiquitin-proteasome proteolytic activity and oxidative stress.

Cardiac structural and hemodynamic changes associated with physiological heart hypertrophy of pregnancy are reversed postpartum.

Pregnancy is associated with ventricular hypertrophy and volume overload. Here we investigated whether late pregnancy is associated with cardiac structural and hemodynamic changes, and if these changes are reversed postpartum. Female mice (C57BL/6) were used in nonpregnant diestrus (NP), late-pregnant (LP), or 7-day postpartum (PP7) stages. Echocardiography and cardiac catheterization were performed to monitor cardiac hemodynamics. Transcript expression of proangiogenic vascular endothelial growth factor, cardiac fetal gene osteopontin, cardiac extracellular matrix-degrading enzymes matrix metalloproteinase-2, and a disintegrin and metalloproteinase-15 and -17 were assessed by RT-PCR. Masson trichrome staining for cardiac fibrosis and endothelial marker CD31 immunostaining for angiogenesis were performed. Heart hypertrophy in LP was fully reversed in PP7 (heart weight: NP = 114 ± 4 mg; LP = 147 ± 2 mg; PP7 = 117 ± 8 mg, P < 0.05 for LP vs. PP7). LP had elevated left ventricular (LV) pressure (119 ± 5 mmHg in LP vs. 92 ± 7 mmHg in NP, P < 0.05) that was restored at PP7 (95 ± 8 mmHg, P < 0.001 vs. LP). LP had increased LV contractility (maximal rate of increase of LV pressure = 6,664 ± 297 mmHg/s in LP vs. 4,294 ± 568 mmHg/s in NP, P < 0.01) that was restored at PP7 (5,313 ± 636 mmHg/s, P < 0.05 vs. LP). LV ejection fraction was reduced in LP (LP = 58 ± 1% vs. NP = 70 ± 4%, P < 0.001) and was already restored at PP1 (77 ± 2%, P < 0.001 vs. LP). Myocardial angiogenesis was significantly increased in LP (capillary density = 1.25 ± 0.02 vs. 0.95 ± 0.01 capillaries/myocyte in NP, P < 0.001) and was fully restored in PP7 (0.98 ± 0.01, P < 0.001 vs. LP). Vascular endothelial growth factor was upregulated in LP (LP = 1.4 ± 0.1 vs. NP = 1 ± 0.1, normalized to NP, P < 0.001) and was restored in PP7 (PP7 = 0.83 ± 0.1, P < 0.001 vs. LP). There was no increase in cardiac fibrosis in LP. Matrix metalloproteinase-2 transcript levels were downregulated in LP (LP = 0.47 ± 0.03 vs. NP = 1 ± 0.01, normalized to NP, P < 0.001) and was restored at PP7 (0.70 ± 0.1, P < 0.001 vs. LP). In conclusion, pregnancy-induced heart hypertrophy is associated with transient cardiac dysfunction, increased cardiac angiogenesis, lack of fibrosis, and decreased expression of remodeling enzymes that are reversed postpartum.

New frontiers in heart hypertrophy during pregnancy.

During Pregnancy, heart develops physiological left ventricular hypertrophy as a result of the natural volume overload. Previously we have characterized the molecular and functional signature of heart hypertrophy during pregnancy. Cardiac hypertrophy during pregnancy is a complex process that involves many changes including in the signalling pathways, composition of extracellular matrix as well as the levels of sex hormones. This review summarises the recent advances and the new frontiers in the context of heart hypertrophy during pregnancy. In particular we focus on structural and extracellular matrix remodelling as well as signalling pathways in pregnancy-induced physiological heart hypertrophy. Emerging evidence shows that various microRNAs modulate key components of hypertrophy, therefore the role of microRNAs in the regulation of gene expression in pregnancy induced hypertrophy is also discussed. We also review the role of ubiquitin proteasome system, the major machinery for the degradation of damaged and misfolded proteins, in heart hypertrophy. The role of sex hormones in particular estrogen in cardiac remodeling during pregnancy is also discussed. We also review pregnancy-induced cardiovascular complications such as peripartum cardiomyopathy and pre-eclampsia and how the knowledge from the animal studies may help us to develop new therapeutic strategies for better treatment of cardiovascular diseases during pregnancy. Special emphasis has to be given to the guidelines on disease management in pregnancy.