Restorative effects of (+)-epicatechin in a rodent model of aging induced muscle atrophy: underlying mechanisms.

Sarcopenia is a progressive and generalized age-related skeletal muscle (SkM) disorder characterized by the accelerated loss of muscle mass (atrophy) and function. SkM atrophy is associated with increased incidence of falls, functional decline, frailty and mortality. In its early stage, SkM atrophy is associated with increased pro-inflammatory cytokine levels and proteasome-mediated protein degradation. These processes also link to the activation of atrophy associated factors and signaling pathways for which, there is a lack of approved pharmacotherapies. The objective of this study, was to characterize the capacity of the flavanol (+)-epicatechin (+Epi) to favorably modulate SkM mass and function in a rat model of aging induced sarcopenia and profile candidate mechanisms. Using 23 month old male Sprague-Dawley rats, an 8 weeks oral administration of the +Epi (1 mg per kg per day in water by gavage) was implemented while control rats only received water. SkM strength (grip), treadmill endurance, muscle mass, myofiber area, creatine kinase, lactate dehydrogenase, troponin, α-actin, tumor necrosis factor (TNF)-α and atrophy related endpoints (follistatin, myostatin, NFκB, MuRF 1, atrogin 1) were quantified in plasma and/or gastrocnemius. We also evaluated effects on insulin growth factor (IGF)-1 levels and downstream signaling (AKT/mTORC1). Treatment of aged rats with +Epi, led to significant increases in front paw grip strength, treadmill time and SkM mass vs. controls as well as beneficial changes in makers of myofiber integrity. Treatment significantly reversed adverse changes in plasma and/or SkM TNF-α, IGF-1, atrophy and protein synthesis related endpoints vs. controls. In conclusion, +Epi has the capacity to reverse sarcopenia associated detrimental changes in regulatory pathways leading to improved SkM mass and function. Given these results and its recognized safety and tolerance profile, +Epi warrants consideration for clinical trials.

(-)-Epicatechin Inhibits Metastatic-Associated Proliferation, Migration, and Invasion of Murine Breast Cancer Cells In Vitro.

Breast cancer, due to its high incidence and mortality, is a public health problem worldwide. Current chemotherapy uses non-specific cytotoxic drugs, which inhibit tumor growth but cause significant adverse effects. (-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids. It is widely distributed in the plant kingdom; it can be found in green tea, grapes, and cocoa. Several studies in animals and humans have shown that EC induces beneficial effects in the skeletal muscle and the cardiovascular system, reducing risk factors such as arterial hypertension, endothelial dysfunction, damage to skeletal muscle structure, and mitochondrial malfunction by promoting mitochondrial biogenesis, with no adverse effects reported. Recently, we reported that EC had an antitumor effect in a murine triple-negative mammary gland tumor model, decreasing tumoral size and volume and increasing survival by 44%. This work aimed to characterize the effects of flavanol EC on proliferation, migration, and metastasis markers of triple-negative murine breast (4T1) cancer cells in culture. We found proliferation diminished and Bax/Bcl2 ratio increased. When the migration of culture cells was evaluated, we observed a significant reduction in migration. Also, the relative expression of the genes associated with metastasis, Cdh1, Mtss1, Pten, Bmrs, Fat1, and Smad4, was increased. In conclusion, these results contribute to understanding molecular mechanisms activated by EC that can inhibit metastatic-associated proliferation, migration, and invasion of murine breast cancer cells.

The TG/HDL-c Lipid Ratio as a Cardiovascular Risk Marker in a Mexican Urban Middle-Class Population: Do We Need a Risk Score Tailored for Mexicans?

INTRODUCTION: Risk scores are essential in primary prevention to detect high-risk patients. The most common scores exclude hypertriglyceridemia and abdominal obesity in their risk assessment. We examined the triglyceride/HDL-cholesterol (TG/HDL-c) ratio as a cardiovascular (CV) risk marker in a middle-class urban Mexican population sample. AIM: Our aim was to test the concept of a scoring system reflecting Mexican population characteristics. METHODS: A total of 2602 healthy adults from the Lindavista primary prevention program were considered, evaluating gender, age, blood pressure, smoking, body mass index, waist circumference, lipid profile, and fasting glucose. According to the abnormality, a score from -3 to +3 was assigned. RESULTS: The summation of eleven variables yielded the Lindavista score (LS), which was calibrated versus the TG/HDL ratio and ACC ASCVD Risk Estimator Plus score to determine its correlation with risk categories. The TG/HDL-c ratio had a linear correlation with LS and high-risk ACC ASCVD categories. CONCLUSIONS: Compared with LS and TG/HDL-c, the ACC ASCVD system underestimates the high-risk category. The high prevalence of obesity and lipid triad in the Mexican population requires a scale that considers those traits. The TG/HDL-c ratio is a practical, easy, and economical instrument to categorize risk in Mexicans.

(-)-Epicatechin Is a Biased Ligand of Apelin Receptor.

(-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids and is widely distributed in the plant kingdom. Several studies have shown the beneficial effects of EC consumption. Many of these reported effects are exerted by activating the signaling pathways associated with the activation of two specific receptors: the G protein-coupled estrogen receptor (GPER), a transmembrane receptor, and the pregnane X receptor (PXR), which is a nuclear receptor. However, the effects of EC are so diverse that these two receptors cannot describe the complete phenomenon. The apelin receptor or APLNR is classified within the G protein-coupled receptor (GPCR) family, and is capable of activating the G protein canonical pathways and the ß-arrestin transducer, which participates in the phenomenon of receptor desensitization and internalization. ß-arrestin gained interest in selective pharmacology and mediators of the so-called "biased agonism". With molecular dynamics (MD) and in vitro assays, we demonstrate how EC can recruit the ß-arrestin in the active conformation of the APLN receptor acting as a biased agonist.

Beneficial Effects of Flavonoids on Skeletal Muscle Health: A Systematic Review and Meta-Analysis.

Skeletal muscle (SkM) is a highly dynamic tissue that responds to physiological adaptations or pathological conditions, and SkM mitochondria play a major role in bioenergetics, regulation of intracellular calcium homeostasis, pro-oxidant/antioxidant balance, and apoptosis. Flavonoids are polyphenolic compounds with the ability to modulate molecular pathways implicated in the development of mitochondrial myopathy. Therefore, it is pertinent to explore its potential application in conditions such as aging, disuse, denervation, diabetes, obesity, and cancer. To evaluate preclinical and clinical effects of flavonoids on SkM structure and function. We performed a systematic review of published studies, with no date restrictions applied, using PubMed and Scopus. The following search terms were used: "flavonoids" OR "flavanols" OR "flavones" OR "anthocyanidins" OR "flavanones" OR "flavan-3-ols" OR "catechins" OR "epicatechin" OR "(-)-epicatechin" AND "skeletal muscle." The studies included in this review were preclinical studies, clinical trials, controlled clinical trials, and randomized-controlled trials that investigated the influence of flavonoids on SkM health. Three authors, independently, assessed trials for the review. Any disagreement was resolved by consensus. The use of flavonoids could be a potential tool for the prevention of muscle loss. Their effects on metabolism and on mitochondria function suggest their use as muscle regulators.

Is it possible to treat nonalcoholic liver disease using a flavanol-based nutraceutical approach? Basic and clinical data.

Nonalcoholic fatty liver disease (NAFLD) is characterized by a spectrum of diseases, ranging from simple steatosis to hepatocellular carcinoma. The main factors for NAFLD are closely related to obesity, insulin resistance, intestinal microbiota alterations, hyperinsulinism, low-grade systemic inflammation, nitroxidative stress, lipid peroxidation, and mitochondrial dysfunction. Currently, the treatment of NAFLD is based on diet and exercise because, to date, there is no specific pharmacological agent, already approved, that raises the need for new therapeutic strategies. Nutraceuticals, such as polyphenols, have potential beneficial effects for health. In this article, the beneficial effects of epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC) are discussed. EGCG is the main catechin in green tea, which has shown in various studies its potential effect preventing and treating NAFLD since it has shown antihyperlipidemic, anti-inflammatory, antifibrotic, antioxidant, and improvement of liver lipid metabolism. However, it has been found that excessive consumption may cause hepatotoxicity. EC is widely distributed in nature (fruits and vegetables). This flavanol has shown many beneficial effects, including antihypertensive, anti-inflammatory, anti-hyperglycemic, antithrombotic, and antifibrotic properties. It increases mitochondrial biogenesis, and it also has effects on the regulation of synthesis and metabolism of lipids. This flavanol is a nontoxic substance; it has been classified by the United States Food and Drug Administration as harmless. The EC-induced effects can be useful for the prevention and/or treatment of NAFLD.

Anticancer potential of (-)-epicatechin in a triple-negative mammary gland model.

OBJECTIVES: The main aim of this work was to analyse the potential tumour growth inhibition effects of (-)-epicatechin (EC). Triple-negative breast cancer (TNBC) is an invasive form of cancer characterized by the absence of progesterone receptor, estrogen receptor and human epidermal growth factor receptor 2. Doxorubicin (DOX) is widely used for its anti-tumour activity. EC belongs to the flavanol subfamily and is a candidate molecule for the adjuvant treatment of cancer due to its antiproliferative activities. METHODS: Evaluation of EC effects and pathways involved in a model of TNBC. KEY FINDINGS: EC inhibited tumour growth as efficiently as DOX (inhibition rates of 74% and 79% for EC and DOX, respectively). The evaluation of adenosine monophosphate-activated protein kinase (AMPK) and Akt phosphorylation and mTOR expression indicates that EC modulates these pathways, resulting in the inhibition of cell proliferation. Additionally, we found an increase in the survival of EC-treated animals compared with control-treated animals. This effect was similar to the effects induced by DOX (survival rates of 44% and 30% for EC and DOX, respectively). CONCLUSION: EC has antiproliferative properties and increases survival in a model of TNBC. These effects may occur through the modulation of deregulated AMPK and Akt/mTOR signalling pathways.

Antifibrotic Effects of (-)-Epicatechin on High Glucose Stimulated Cardiac Fibroblasts.

Cardiac fibrosis is one of the hallmarks of a diabetic cardiomyopathy. When activated, cardiac fibroblasts (CFs) increase the production of extracellular matrix proteins. Transforming growth factor (TGF)-ß1 is known to mediate cardiac fibrosis through the SMAD pathway. High glucose (HG = 25 mM) cell culture media can activate CFs using TGF-ß1. There is a need to identify effective antifibrotic agents. Studies in animals indicate that treatment with (-)-epicatechin (Epi) appears capable of reducing myocardial fibrosis. Epi binds to G-protein coupled estrogen receptor (GPER) and activates downstream pathways. We evaluated the potential of Epi to mitigate the development of a profibrotic phenotype in HG stimulated CFs. CF primary cultures were isolated from young male rats and were exposed for up to 48 h HG media and treated with vehicle or 1 µM Epi. Relevant profibrotic end points were measured by the use of various biochemical assays. HG exposure of CFs increased TGF-ß1 protein levels by ∼15%, fibronectin ∼25%, urea levels ∼60%, proline incorporation ∼70%, and total collagen ∼15%. Epi treatment was able to significantly block HG induced increases in TGF-ß1, fibronectin, urea, proline, and total collagen protein levels. GPER levels were reduced by HG and restored in CFs treated with Epi an effect associated with the activation (i.e., phosphorylation) of c-Src. Epi treatment also reverted SMAD levels. Altogether, results demonstrate that CFs cultured in HG acquire a profibrotic phenotype, which is blocked by Epi an effect, likely mediated at least, in part, by GPER effects on the SMAD/TGF-ß1 pathway.

[Breast cancer, the risk attributable to type 2 diabetes]. / Cáncer de mama, el riesgo atribuible a diabetes tipo 2.

BACKGROUND: Several studies have evaluated the association between a history of type 2 diabetes (T2D) and risk of breast cancer (BC), with controversial results. However, information regarding the population-attributable risk percent (PAR%) remains scarce. Objective: To estimate the association and the PAR% for BC and T2D, lifestyle and gynecologic factors in women in Mexico City. METHODS: This case-control study was performed from May-December 2020. Women >40 years of age, from Mexico City, with a confirmed diagnosis for BC were included as cases. Controls were women with a BIRADS 1 or 2 mammography or an ultrasound clear of any BC suggestive findings. RESULTS: A total of 134 cases and 134 controls were included. A higher risk for BC was identified among women who did not perform routine physical activity and those who had a history of hormonal contraceptive use > 5 years. The use of hormone replacement therapy (HRT) was associated with an odds ratio (OR) of 5.0 (p = 0.22) in the first model. After adjustment, HRT was associated with an OR of 2.92 (p=0.492) in the second and an OR of 3.6 (p = 0.753) in the third model. T2D was associated with an OR of 1.04 (p = 0.96) in the first model; an OR of 0.65 (p = 0.65) in the second model and an OR of RMa 0.75(p = 0.79) for the third model. CONCLUSION: In this case-control study, there was no significant association identified between a T2D diagnosis and BC.

INTRODUCCIÓN: diversas investigaciones han evaluado el riesgo de cáncer de mama (CaMa) asociado a diabetes tipo 2 (DT2) con resultados inconsistentes. Pocas investigaciones han evaluado el porcentaje de riesgo atribuible a la población (PAR%). OBJETIVO: estimar la asociación y el PAR% para CaMa por DT2, así como los factores del estilo de vida y ginecológicos en mujeres de la Ciudad de México. MÉTODOS: estudio de casos y controles, realizado de mayo a diciembre de 2020. Se incluyeron mujeres > 40 años, de la Ciudad de México, con diagnóstico confirmado de CaMa. Los controles fueron mujeres con una mastografía BIRADS 1 o 2, o ultrasonido mamario sin datos sugestivos de CaMa. RESULTADOS: se incluyeron en total 134 casos y 134 controles. Se identificó un mayor riesgo de CaMa en aquellas mujeres que no realizan actividad física y con el uso de anticonceptivos > 5 años. El uso de terapia de reemplazo hormonal (TRH) se asoció con una razón de momios ajustada (RMa) de 5.0, p = 0.22 en el modelo 1. Conforme se ajustan los modelos, la TRH para el modelo 2 tuvo una RMa de 2.92, p = 0.492 y en el modelo 3 una RMa de 3.6 p = 0.753. La presencia de diabetes se asoció a una RMa de 1.04, p = 0.96 en el modelo 1; RMa de 0.65, p = 0.65 en el modelo 2 y una RMa de 0.75, p = 0.79 en el modelo 3. CONCLUSIONES: en este estudio de casos y controles no se encontró asociación entre el diagnóstico de DT2 y CaMa.

Antihyperglycemic and Lipid Profile Effects of Salvia amarissima Ortega on Streptozocin-Induced Type 2 Diabetic Mice.

Salvia amarissima Ortega was evaluated to determinate its antihyperglycemic and lipid profile properties. Petroleum ether extract of fresh aerial parts of S. amarissima (PEfAPSa) and a secondary fraction (F6Sa) were evaluated to determine their antihyperglycemic activity in streptozo-cin-induced diabetic (STID) mice, in oral tolerance tests of sucrose, starch, and glucose (OSTT, OStTT, and OGTT, respectively), in terms of glycated hemoglobin (HbA1c), triglycerides (TG), and high-density lipoprotein (HDL). In acute assays at doses of 50 mg/kg body weight (b.w.), PEfAPSa and F6Sa showed a reduction in hyperglycemia in STID mice, at the first and fifth hour after of treatment, respectively, and were comparable with acarbose. In the sub-chronic test, PEfAPSa and F6Sa showed a reduction of glycemia since the first week, and the effect was greater than that of the acarbose control group. In relation to HbA1c, the treatments prevented the increase in HbA1c. In the case of TG and HDL, PEfAPSa and F6Sa showed a reduction in TG and an HDL increase from the second week. OSTT and OStTT showed that PEfAPSa and F6Sa significantly lowered the postprandial peak at 1 h after loading but only in sucrose or starch such as acarbose. The results suggest that S. amarissima activity may be mediated by the inhibition of disaccharide hydrolysis, which may be associated with an α-glucosidase inhibitory effect.

(-)-Epicatechin induces mitochondrial biogenesis and markers of muscle regeneration in adults with Becker muscular dystrophy.

INTRODUCTION: We conducted an open-label study to examine the effects of the flavonoid (-)-epicatechin in seven ambulatory adult patients with Becker muscular dystrophy (BMD). METHODS: Seven participants received (-)-epicatechin 50 mg twice per day for 8 weeks. Pre- and postprocedures included biceps brachii biopsy to assess muscle structure and growth-relevant endpoints by western blotting, mitochondria volume measurement, and cristae abundance by electron microscopy, graded exercise testing, and muscle strength and function tests. RESULTS: Western blotting showed significantly increased levels of enzymes modulating cellular bioenergetics (liver kinase B1 and 5'-adenosine monophosphate-activated protein kinase). Peroxisome proliferator-activated receptor gamma coactivator-1alpha, a transcriptional coactivator of genes involved in mitochondrial biogenesis and cristae-associated mitofilin levels, increased as did cristae abundance. Muscle and plasma follistatin increased significantly while myostatin decreased. Markers of skeletal muscle regeneration myogenin, myogenic regulatory factor-5, myoblast determination protein 1, myocyte enhancer factor-2, and structure-associated proteins, including dysferlin, utrophin, and intracellular creatine kinase, also increased. Exercise testing demonstrated decreased heart rate, maximal oxygen consumption per kilogram, and plasma lactate levels at defined workloads. Tissue saturation index improved in resting and postexercise states. DISCUSSION: (-)-Epicatechin, an exercise mimetic, appears to have short-term positive effects on tissue biomarkers indicative of mitochondrial biogenesis and muscle regeneration, and produced improvements in graded exercise testing parameters in patients with BMD.

Effects of (-)-epicatechin on neuroinflammation and hyperphosphorylation of tau in the hippocampus of aged mice.

Evidence has implicated oxidative stress (OS) and inflammation as drivers of neurodegenerative pathologies. We previously reported on the beneficial effects of (-)-epicatechin (Epi) treatment on aging-induced OS and its capacity to restore modulators of mitochondrial biogenesis in the prefrontal cortex of 26-month-old male mice. In the present study using the same mouse model of aging, we examined the capacity of Epi to mitigate hippocampus OS, inflammation, hyperphosphorylation of tau protein, soluble ß-amyloid protein levels, cell survival, memory, anxiety-like behavior levels and systemic inflammation. Mice were subjected to 4 weeks of Epi treatment (1 mg kg-1 day-1) and samples of the hippocampus were obtained. Assessments of the OS markers, protein carbonyls, and malondialdehyde levels demonstrated their significant increase (∼3 fold) with aging that were partially suppressed by Epi. The protein levels of the glial fibrillary acidic protein, inflammatory factor 1 (Iba1), pro-inflammatory cytokines, interleukins (IL-1ß, IL-3, 5, 6 and 15), cyclooxygenase 2, tumor necrosis factor α, nuclear factor-activated B cells and interferon γ increase with aging and were also significantly decreased with Epi treatment. However, anti-inflammatory cytokines, IL-1ra, IL-10 and 11 decrease with aging and were restored with Epi. Epi also reversed the aging effects on the hyperphosphorylation of tau, increased soluble ß-amyloid levels (∼2 fold), cellular death (as per caspase 3 and 9 activity), and reduced nerve growth factor and triggering receptor expressed on myeloid cells 2 levels. Measures of anxiety like-behavior and memory demonstrated improvements with Epi treatment. Indicators of systemic inflammation increase with aging and Epi was capable of decreasing blood inflammatory markers. Altogether, the results show a significant capacity of Epi to mitigate hippocampus OS and inflammation leading to improved brain function.

Restricted Water Intake and Hydration with Fructose-Containing Beverages during Infancy Predispose to Aggravate an Acute Renal Ischemic Insult in Adolescent Rats.

We aimed to investigate the effects of chronic fluid restriction and hydration with a sweetened beverage (SB) in rats from weaning until adolescence, in a posterior acute kidney injury (AKI) event induced by ischemia-reperfusion (I/R). We followed 5 groups of weaning rats: control group (C); two groups with 22 h/day fluid restriction, a group hydrated for two hours with water (-W) and a group hydrated with SB; one group receiving SB ad libitum all day (+SB); and one group in which water consumption was increased using a gel diet. The rats that reached adolescence were submitted to I/R. Fluid restriction and/or SB hydration induced mild renal alterations that were significantly accentuated in the -SB group and resulted in worse outcomes after I/R-induced AKI that resulted in a catastrophic fall in creatinine clearance and diffuse acute tubular necrosis. In summary, low tap water intakes, as well as SB intake in infancy, prompt kidney worse outcomes in a later event of AKI during adolescence and both insults magnify kidney damage. Studies on hydration habits in children are recommended to disclose the potentially harmful effects that those behavioral patterns might carry to future renal health.

Randomized Trial of Deep Vein Thrombosis Chemoprophylaxis with Bemiparin and Enoxaparin in Patients with Moderate to High Thrombogenic Risk Undergoing Plastic and Reconstructive Surgery Procedures.

BACKGROUND: Deep vein thrombosis (DVT) is a common complication during postoperative convalescence characterized by hypercoagulability, vascular endothelium damage and blood stasis. It increases noticeably in peri/postoperative phases of surgery procedures. Pulmonary embolism secondary to iliofemoral DVT is a frequent cause of death. METHODS: Adult patients scheduled for plastic and reconstructive surgery (PRSx) with moderate to high thrombogenic risk were selected. We evaluated the efficacy and safety of bemiparin compared to enoxaparin as chemoprophylaxis for DVT. Following balanced general anesthesia techniques, patients were randomly assigned for subcutaneous enoxaparin 40 IU (Group-E) or bemiparin 3500 IU (Group-B) q24h starting 6 h after procedure conclusion for at least 10 days. All patients were evaluated for DVT through Doppler ultrasound mapping of the lower limbs. RESULTS: Seventy-eight patients were evaluated, mostly women (83%), physical status ASA II (59%), ASA III (10%); Caprini's thrombogenic risk score 3-4 (moderate) 58%, 5-6 (high) 29%, > 6 (too high) 13%; demographics, clinical variables and scores were similar between groups. Median drainage time in breast surgery was 4 days in both groups (p = 0.238). In the case of abdominal surgery, median was 14 days in Group-E versus 13 days in Group-B (p = 0.059). No DVT was detected in either group. CONCLUSIONS: DVT was prevented with bemiparin, without significant bleeding increase nor adverse events; moreover, the cost of bemiparin is lower than enoxaparin. Bemiparin can be considered as alternative drug for DVT chemoprophylaxis in PRSx procedures. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

High Flavonoid Cocoa Supplement Ameliorates Plasma Oxidative Stress and Inflammation Levels While Improving Mobility and Quality of Life in Older Subjects: A Double-Blind Randomized Clinical Trial.

BACKGROUND: The age-related decline in mass, strength, and performance of skeletal muscle is associated with loss of independence, falls risk, disability, institutionalization, and death. METHODS: To determine whether a cocoa supplement enriched in flavonoids can improve plasma markers of oxidative stress and inflammation, physical performance and frailty in middle-aged and older subjects, we conducted a two-phase, randomized, double-blind, clinical trial. The initial study included 60 subjects (55- to 70-year-old) allocated into placebo (P), highly alkalinized (no-flavonoid; NF), or flavonoid-rich natural cocoa (F) beverage groups. The follow-up study included 74 older subjects (65- to 90-year-old) randomly distributed into NF or F groups. Subjects were instructed to consume the beverages once/day for up to 12-weeks. A comprehensive (aging relevant) set of end points were assessed, which included mean change in blood plasma metabolic and oxidative stress indicators, in physical performance tests and quality of life (QoL). RESULTS: In the initial study, the F group showed improved glycemia, triglyceridemia, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, triglyceridemia/HDL index, and oxidative markers. Performance on the Up and Go test, skeletal muscle index, and quality of life also improved. In the follow-up study, F treatment was associated with significant improvements in metabolic, oxidative stress, and inflammatory endpoints and positive effects on physical performance, frailty indicators, and quality of life (F vs. NF group). CONCLUSIONS: Regular flavonoids consumption positively affects blood oxidative stress and inflammation end points, cardiometabolic risk markers, physical performance, and quality of life. The sum of such effects may help to mitigate the extent of frailty development in the elderly people. TRIAL REGISTRATION: NCT03585868.

Structural and energetic basis for novel epicatechin derivatives acting as GPER agonists through the MMGBSA method.

(-)-Epicatechin (Epi) has been demonstrated to activate pathways involved in GPER-stimulated nitric oxide (NO) production via endothelial NO synthase, known as the eNOS/NO pathway. Previous studies combining synthesis of four Epi derivatives demonstrated that Epi and Epi-prop, Epi-4-prop and Epi-5-prop were able to bind GPER by acting as GPER agonists, whereas docking studies allowed observation of structural details of the binding of these derivatives at the GPER binding site. However, due to the nature of past studies, the theoretical methods employed did not allow observation of structural and energetic details linked to ligand binding at the GPER binding site. In this contribution, we explore the structural and energetic changes coupling the binding of Epi and its four derivatives to GPER. To this end, MD simulations on the microsecond scale (1 µs) with an MMGBSA approach were used for each GPER-ligand complex. Energetic analysis demonstrated that incorporation of several aliphatic chains to Epi contributed to increasing the affinity towards the GPER binding site, thus helping to explain the experimental evidence. Structural analysis demonstrated that Epi, Epi-4-prop and Epi-5-prop share more similar interactions at GPER binding sites with similar conformational behavior than with Epi-prop and Epi-Ms. However, Epi-prop had additional residues that could explain its different but related biological effects.

Unmasking of oestrogen-dependent changes in left ventricular structure and function in aged female rats: a potential model for pre-heart failure with preserved ejection fraction.

KEY POINTS: Heart failure with preserved ejection fraction (HFpEF) is seen more frequently in older women; risk factors include age, hypertension and excess weight. No female animal models of early stage remodelling (pre-HFpEF) have examined the effects that the convergence of such factors have on cardiac structure and function. In this study, we demonstrate that ageing can lead to the development of mild chamber remodelling, diffuse fibrosis and loss of diastolic function. The loss of oestrogens further aggravates such changes by leading to a notable drop in cardiac output (while preserving normal ejection fraction) in the presence of diffuse fibrosis that is more predominant in endocardium and is accompanied by papillary fibrosis. Excess weight did not markedly aggravate such findings. This animal model recapitulates many of the features recognized in older, female HFpEF patients and thus, may serve to examine the effects of candidate therapeutic agents. ABSTRACT: Two-thirds of patients with heart failure with preserved ejection fraction (HFpEF) are older women, and risk factors include hypertension and excess weight/obesity. Pathophysiological factors that drive early disease development (before heart failure ensues) remain obscure and female animal models are lacking. The study evaluated the intersecting roles of ageing, oestrogen depletion and excess weight on altering cardiac structure/function. Female, 18-month-old, Fischer F344 rats were divided into an aged group, aged + ovariectomy (OVX) and aged + ovariectomy + 10% fructose (OVF) in drinking water (n = 8-16/group) to induce weight gain. Left ventricular (LV) structure/function was monitored by echocardiography. At 22 months of age, animals were anaesthetized and catheter-based haemodynamics evaluated, followed by histological measures of chamber morphometry and collagen density. All aged animals developed hypertension. OVF animals increased body weight. Echocardiography only detected mild chamber remodelling with ageing while intraventricular pressure-volume loop analysis showed significant (P < 0.05) decreases vs. ageing in stroke volume (13% OVX and 15% for OVF), stroke work (34% and 52%) and cardiac output (29% and 27%), and increases in relaxation time (10% OVX) with preserved ejection fraction. Histology indicated papillary and interstitial fibrosis with ageing, which was higher in the endocardium of OVX and OVF groups. With ageing, ovariectomy leads to the loss of diastolic and global LV function while preserving ejection fraction. This model recapitulates many cardiovascular features present in HFpEF patients and may help understand the roles that ageing and oestrogen depletion play in early (pre-HFpEF) disease development.

Synthesis of novel (-)-epicatechin derivatives as potential endothelial GPER agonists: Evaluation of biological effects.

To potentially identify proteins that interact (i.e. bind) and may contribute to mediate (-)-epicatechin (Epi) responses in endothelial cells we implemented the following strategy: 1) synthesis of novel Epi derivatives amenable to affinity column use, 2) in silico molecular docking studies of the novel derivatives on G protein-coupled estrogen receptor (GPER), 3) biological assessment of the derivatives on NO production, 4) implementation of an immobilized Epi derivative affinity column and, 5) affinity column based isolation of Epi interacting proteins from endothelial cell protein extracts. For these purposes, the Epi phenol and C3 hydroxyl groups were chemically modified with propargyl or mesyl groups. Docking studies of the novel Epi derivatives on GPER conformers at 14 ns and 70 ns demostrated favorable thermodynamic interactions reaching the binding site. Cultures of bovine coronary artery endothelial cells (BCAEC) treated with Epi derivatives stimulated NO production via Ser1179 phosphorylation of eNOS, effects that were attenuated by the use of the GPER blocker, G15. Epi derivative affinity columns yielded multiple proteins from BCAEC. Proteins were electrophoretically separated and inmmunoblotting analysis revealed GPER as an Epi derivative binding protein. Altogether, these results validate the proposed strategy to potentially isolate and identify novel Epi receptors that may account for its biological activity.

A pilot study on clinical pharmacokinetics and preclinical pharmacodynamics of (+)-epicatechin on cardiometabolic endpoints.

We reported that (-)-epicatechin can stimulate mitochondria biogenesis and improve metabolism. However, preliminary studies indicate that the (+) stereoisomer form may be more potent. We evaluated in a preliminary manner, the pharmacokinetics (PK) and initial safety analysis of (+)-epicatechin ((+)-Epi) in healthy and pre-diabetic subjects. Using a mouse model of diet-induced obesity and insulin resistance, we also evaluated the metabolic effects of (+)-Epi vs. (+)-catechin (Cat) to determine class effects. In the Phase I PK study, subjects were provided a single incremental oral dose of (+)-Epi (10, 30 or 100 mg). For the PD study, subjects were provided a single 30 mg dose per day for 7 days. Blood samples were collected and safety measures were performed. Incremental doses of (+)-Epi increase the half-life of blood metabolites from 1.2-4.9 h. The compound was well tolerated and no adverse effects were reported. Seven day dosing of pre-diabetic subjects led to tendencies for reductions in circulating levels of tumor necrosis factor-α and monocyte chemoattractant protein-1, which returned to baseline by 7 days after treatment. In animals, 2 weeks of oral dosing (0.003, 0.01, 0.03, 0.1 and 0.3 mg kg-1 day-1) dose dependently improved metabolism-related endpoints (weight gain, glucose, cholesterol, triglyceride, with thresholds as low as 0.01 mg kg-1 day-1). Cat yielded no effects at 0.1 mg kg-1 day-1. Results indicate that (+)-Epi evidences a favorable PK and safety profile. Using a pre-clinical model, the compound positively modulates metabolism, which may link to mitochondrial effects. Effects are not due to general antioxidant actions, as Cat yielded no effects.