Effects of (-)-epicatechin and derivatives on nitric oxide mediated induction of mitochondrial proteins

(-)-epicatechin treatment did not modify the thermogenic pathway in the gastrocnemius muscle of male rat offspring obeses by programming

The aim of this study was to analyse the expression of genes related to the regulation of energy metabolism in skeletal muscle tissue by comparing male offspring in two age groups [at 110 and 245 postnatal days (pnd)] from a mother with obesity induced by a high-fat diet and (-)-epicatechin (Epi) administration. Four groups of six male offspring from different litters were randomly selected for the control groups [C and offspring of mothers with maternal obesity (MO)] or Epi intervention groups. We evaluated the effect of Epi on gastrocnemius tissue by analysing the mRNA and protein expression levels of Fndc5/irisin, Pgc-1α, Ucp3, and Sln. Epi significantly increased the Pgc-1α protein in the MO group of offspring at 110 pnd (p < 0.036, MO vs. MO+Epi), while at 245 pnd, Epi increased Fndc5/irisin mRNA expression in the MO+Epi group versus the MO group (p = 0.006).No differences were detected in Fndc5/irisin, Ucp3 or Sln mRNA or protein levels (including Pgc-1α mRNA) in the offspring at 110 pnd or in Pgc-1α, Ucp3, or Sln mRNA or protein levels (including Fndc5/irisin protein) at 245 pnd among the experimental groups. In conclusion, (-)-epicatechin treatment increased Fndc5/irisin mRNA expression and Pgc-α protein levels in the gastrocnemius muscle of offspring at postnatal days 110 and 245. Furthermore, it is suggested that the flavonoid effect in a model of obesity and its impact on thermogenesis in skeletal muscle are regulated by a different pathway than Fndc5/irisin.

Dietary apple polyphenols enhance mitochondrial turnover and respiratory chain enzymes

Previous studies have demonstrated the beneficial effects of apple polyphenol (AP) intake on muscle endurance. Since mitochondria are critical for muscle endurance, we investigated mitochondrial enzyme activity, biogenesis, degradation and protein quality control. Twenty-four Wistar rats were randomly fed a 5% AP diet (5% AP group, n = 8), a 0.5% AP diet (0.5% AP group, n = 8), or a control diet (control group, n = 8). After a 4-week feeding period, the expression level of peroxisome proliferator-activated receptor γ coactivator-1α, a mitochondrial biosynthetic factor, did not increase, whereas that of transcription factor EB, another regulator of mitochondrial synthesis, significantly increased. Moreover, the mitochondrial count did not differ significantly between the groups. In contrast, mitophagy-related protein levels were significantly increased. The enzymatic activities of mitochondrial respiratory chain complexes II, III and IV were significantly higher in the AP intake group than in the control group. We conclude that AP feeding increases the activity of respiratory chain complex enzymes in rat skeletal muscles. Moreover, mitochondrial biosynthesis and degradation may have increased in AP-treated rats. NEW FINDINGS: What is the central question of this study? Does the administration of apple polyphenols (AP) affect mitochondrial respiratory chain complex enzyme activity, biogenesis, degradation and protein quality control in rat skeletal muscles? What is the main finding and its importance? AP feeding increases respiratory chain complex enzyme activity in rat skeletal muscle. Moreover, AP administration increases transcription factor EB activation, and mitophagy may be enhanced to promote degradation of dysfunctional mitochondria, but mitochondrial protein quality control was not affected.

(-)-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.

Natural Products as Modulators of Mitochondrial Dysfunctions Associated with Cardiovascular Diseases: Advances and Opportunities

The mitochondria have an important role in modulating cell cycle progression, cell survival, and apoptosis. In the adult heart, the cardiac mitochondria have a unique spatial arrangement and occupy nearly one-third the volume of a cardiomyocyte, being highly efficient for converting the products of glucose or fatty acid metabolism into adenosine triphosphate (ATP). In cardiomyocytes, the decline of mitochondrial function reduces ATP generation and increases the production of reactive oxygen species, which generates impaired heart function. This is because mitochondria play a key role in maintaining cytosolic calcium concentration and modulation of muscle contraction, as ATP is required to dissociate actin from myosin. Beyond that, mitochondria have a significant role in cardiomyocyte apoptosis because it is evident that patients who have cardiovascular diseases (CVDs) have increased mitochondrial DNA damage to the heart and aorta. Many studies have shown that natural products have mitochondria-modulating effects in cardiac diseases, determining them as potential candidates for new medicines. This review outlines the leading plant secondary metabolites and natural compounds derived from microorganisms as modulators of mitochondrial dysfunctions associated with CVDs.

Effect of flavonoids on skeletal muscle mass, strength and physical performance in middle-aged and older adults with or without Sarcopenia: A meta-analysis of randomized controlled trials

The role of flavonoids in regulating the synthesis and function of skeletal muscles is increasingly recognized. However, randomized controlled trials have yielded inconsistent results on the influence of flavonoids on human muscular parameters. Therefore, we performed a meta-analysis to evaluate the possible effects of flavonoids on sarcopenia-related parameters in middle-aged and elderly people. Eligible literature and randomized controlled trials reports have been extensively searched from PubMed, Cochrane Library, Web of Science, and EMBASE databases until April 2022. A total of 20 articles involving 796 participants were available for the meta-analysis. There were significant benefits for participants in appendicular muscle mass gain (SMD = 0.29; 95% CI: 0.07, 0.52; P = 0.01) and 6-min walk distance (SMD = 0.37; 95% CI: 0.01, 0.73; P = 0.05). A subgroup analysis indicated that flavonoid significantly improves appendicular muscle mass (SMD = 0.50; 95% CI: 0.21, 0.80; P < 0.01) and Timed-Up and Go test (SMD = −0.47; 95% CI: −0.85, −0.09; P = 0.02) in Sarcopenia population. Our results provide insight into the effects of flavonoids on skeletal muscle mass and gait speed for those without exercise. However, there was no significant improvement in the subjects' muscle strength.

Djhsp60 Is Required for Planarian Regeneration and Homeostasis

HSP60, a well-known mitochondrial chaperone, is essential for mitochondrial homeostasis. HSP60 deficiency causes dysfunction of the mitochondria and is lethal to animal survival. Here, we used freshwater planarian as a model system to investigate and uncover the roles of HSP60 in tissue regeneration and homeostasis. HSP60 protein is present in all types of cells in planarians, but it is relatively rich in stem cells and head neural cells. Knockdown of HSP60 by RNAi causes head regression and the loss of regenerating abilities, which is related to decrease in mitotic cells and inhibition of stem cell-related genes. RNAi-HSP60 disrupts the structure of the mitochondria and inhibits the mitochondrial-related genes, which mainly occur in intestinal tissues. RNAi-HSP60 also damages the integrity of intestinal tissues and downregulates intestine-expressed genes. More interestingly, RNAi-HSP60 upregulates the expression of the cathepsin L-like gene, which may be the reason for head regression and necrotic-like cell death. Taking these points together, we propose a model illustrating the relationship between neoblasts and intestinal cells, and also highlight the essential role of the intestinal system in planarian regeneration and tissue homeostasis.

(-)-Epicatechin Improves Vasoreactivity and Mitochondrial Respiration in Thermoneutral-Housed Wistar Rat Vasculature

Cardiovascular disease (CVD) is a global health concern. Vascular dysfunction is an aspect of CVD, and novel treatments targeting vascular physiology are necessary. In the endothelium, eNOS regulates vasodilation and mitochondrial function; both are disrupted in CVD. (−)-Epicatechin, a botanical compound known for its vasodilatory, eNOS, and mitochondrial-stimulating properties, is a potential therapy in those with CVD. We hypothesized that (−)-epicatechin would support eNOS activity and mitochondrial respiration, leading to improved vasoreactivity in a thermoneutral-derived rat model of vascular dysfunction. We housed Wistar rats at room temperature or in thermoneutral conditions for a total of 16 week and treated them with 1mg/kg body weight (−)-epicatechin for 15 day. Vasoreactivity, eNOS activity, and mitochondrial respiration were measured, in addition to the protein expression of upstream cellular signaling molecules including AMPK and CaMKII. We observed a significant improvement of vasodilation in those housed in thermoneutrality and treated with (−)-epicatechin (p < 0.05), as well as dampened mitochondrial respiration (p < 0.05). AMPK and CaMKIIα and β expression were lessened with (−)-epicatechin treatment in those housed at thermoneutrality (p < 0.05). The opposite was observed with animals housed at room temperature supplemented with (−)-epicatechin. These data illustrate a context-dependent vascular response to (−)-epicatechin, a candidate for CVD therapeutic development.

( -)-Epicatechin and cardiometabolic risk factors: a focus on potential mechanisms of action

This review summarizes experimental evidence on the beneficial effects of ( -)-epicatechin (EC) attenuating major cardiometabolic risk factors, i.e., dyslipidemias, obesity (adipose tissue dysfunction), hyperglycemia (insulin resistance), and hypertension (endothelial dysfunction). Studies in humans are revised and complemented with experiments in animal models, and cultured cells, aiming to understand the molecular mechanisms involved in EC-mediated effects. Firstly, an assessment of EC metabolism gives relevance to both conjugated-EC metabolites product of host metabolism and microbiota-derived species. Integration and analysis of results stress the maintenance of redox homeostasis and mitigation of inflammation as relevant processes associated with cardiometabolic diseases. In these processes, EC appears having significant effects regulating NADPH oxidase (NOX)-dependent oxidant production, nitric oxide (NO) production, and energy homeostasis (mitochondrial biogenesis and function). The potential participation of cell membranes and membrane-bound receptors is also discussed in terms of direct molecular action of EC and EC metabolites reaching cells and tissues.

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)-β1 is known to mediate cardiac fibrosis through the SMAD pathway. High glucose (HG = 25 mM) cell culture media can activate CFs using TGF-β1. 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-β1 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-β1, 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-β1 pathway.

Dietary Cocoa Flavanols Enhance Mitochondrial Function in Skeletal Muscle and Modify Whole-Body Metabolism in Healthy Mice

Mitochondrial dysfunction is widely reported in various diseases and contributes to their pathogenesis. We assessed the effect of cocoa flavanols supplementation on mitochondrial function and whole metabolism, and we explored whether the mitochondrial deacetylase sirtuin-3 (Sirt3) is involved or not. We explored the effects of 15 days of CF supplementation in wild type and Sirt3^-/- mice. Whole-body metabolism was assessed by indirect calorimetry, and an oral glucose tolerance test was performed to assess glucose metabolism. Mitochondrial respiratory function was assessed in permeabilised fibres and the pyridine nucleotides content (NAD⁺ and NADH) were quantified. In the wild type, CF supplementation significantly modified whole-body metabolism by promoting carbohydrate use and improved glucose tolerance. CF supplementation induced a significant increase of mitochondrial mass, while significant qualitative adaptation occurred to maintain H₂O₂ production and cellular oxidative stress. CF supplementation induced a significant increase in NAD⁺ and NADH content. All the effects mentioned above were blunted in Sirt3^-/- mice. Collectively, CF supplementation boosted the NAD metabolism that stimulates sirtuins metabolism and improved mitochondrial function, which likely contributed to the observed whole-body metabolism adaptation, with a greater ability to use carbohydrates, at least partially through Sirt3.

Dietary cocoa ameliorates non-alcoholic fatty liver disease and increases markers of antioxidant response and mitochondrial biogenesis in high fat-fed mice

Cocoa powder, derived Theobroma cacao, is a popular food ingredient that is commonly consumed in chocolate. Epidemiological and human intervention studies have reported that chocolate consumption is associated with reduced risk of cardiometabolic diseases. Laboratory studies have reported the dietary supplementation with cocoa or cocoa polyphenols can improve obesity and obesity-related comorbidities in preclinical models. Non-alcoholic fatty liver disease (NAFLD), one such comorbidity, is a risk factor for cirrhosis and hepatocellular carcinoma. Limited studies have examined the effect of cocoa/chocolate on NAFLD and underlying hepatoprotective mechanisms. Here, we examined the hepatoprotective effects of dietary supplementation with 80 mg/g cocoa powder for 10 wks in high fat (HF)-fed obese male C57BL/6J mice. We found that cocoa-supplemented mice had lower rate of body weight gain (22%), hepatic triacylglycerols (28%), lipid peroxides (57%), and mitochondrial DNA damage (75%) than HF-fed controls. These changes were associated with higher hepatic superoxide dismutase and glutathione peroxidase enzyme activity and increased expression of markers of hepatic mitochondrial biogenesis. We also found that the hepatic protein expression of sirtuin 3 (SIRT3), and mRNA expression of peroxisome proliferator activated receptor g coactivator (PGC) 1a, nuclear respiratory factor 1, and forkhead box O3 were higher in cocoa-treated mice compared to HF-fed controls. These factors play a role in coordinating mitochondrial biogenesis and expression of mitochondrial antioxidant response factors. Our results indicate that cocoa supplementation can mitigate the severity of NAFLD in obese mice and that these effects are related to SIRT3/PGC1a-mediated increases in antioxidant response and mitochondrial biogenesis.

Regulation of Cytochrome c Oxidase by Natural Compounds Resveratrol, (-)-Epicatechin, and Betaine

Numerous naturally occurring molecules have been studied for their beneficial health effects. Many compounds have received considerable attention for their potential medical uses. Among them, several substances have been found to improve mitochondrial function. This review focuses on resveratrol, (–)-epicatechin, and betaine and summarizes the published data pertaining to their effects on cytochrome c oxidase (COX) which is the terminal enzyme of the mitochondrial electron transport chain and is considered to play an important role in the regulation of mitochondrial respiration. In a variety of experimental model systems, these compounds have been shown to improve mitochondrial biogenesis in addition to increased COX amount and/or its enzymatic activity. Given that they are inexpensive, safe in a wide range of concentrations, and effectively improve mitochondrial and COX function, these compounds could be attractive enough for possible therapeutic or health improvement strategies.

Effects of (-)-epicatechin on mitochondria

Mitochondrial dysfunction is observed in a broad range of human diseases, including rare genetic disorders and complex acquired pathologies. For this reason, there is increasing interest in identifying safe and effective strategies to mitigate mitochondrial impairments. Natural compounds are widely used for multiple indications, and their broad healing properties suggest that several may improve mitochondrial function. This review focuses on (-)-epicatechin, a monomeric flavanol, and its effects on mitochondria. The review summarizes the available data on the effects of acute and chronic (-)-epicatechin supplementation on mitochondrial function, outlines the potential mechanisms involved in mitochondrial biogenesis induced by (-)-epicatechin supplementation and discusses some future therapeutic applications.

(-)-Epicatechin Modulates Mitochondrial Redox in Vascular Cell Models of Oxidative Stress

Diabetes mellitus affects 451 million people worldwide, and people with diabetes are 3-5 times more likely to develop cardiovascular disease. In vascular tissue, mitochondrial function is important for vasoreactivity. Diabetes-mediated generation of excess reactive oxygen species (ROS) may contribute to vascular dysfunction via damage to mitochondria and regulation of endothelial nitric oxide synthase (eNOS). We have identified (–)-epicatechin (EPICAT), a plant compound and known vasodilator, as a potential therapy. We hypothesized that mitochondrial ROS in cells treated with antimycin A (AA, a compound targeting mitochondrial complex III) or high glucose (HG, global perturbation) could be normalized by EPICAT, and correlate with improved mitochondrial dynamics and cellular signaling. Human umbilical vein endothelial cells (HUVEC) were treated with HG, AA, and/or 0.1 or 1.0 μM of EPICAT. Mitochondrial and cellular superoxide, mitochondrial respiration, and cellular signaling upstream of mitochondrial function were assessed. EPICAT at 1.0 μM significantly attenuated mitochondrial superoxide in HG-treated cells. At 0.1 μM, EPICAT nonsignificantly increased mitochondrial respiration, agreeing with previous reports. EPICAT significantly increased complex I expression in AA-treated cells, and 1.0 μM EPICAT significantly decreased mitochondrial complex V expression in HG-treated cells. No significant effects were seen on either AMPK or eNOS expression. Our study suggests that EPICAT is useful in mitigating moderate ROS concentrations from a global perturbation and may modulate mitochondrial complex activity. Our data illustrate that EPICAT acts in the cell in a dose-dependent manner, demonstrating hormesis.

Advances in physiological functions and mechanisms of (-)-epicatechin

(-)-Epicatechin (EC) is a flavanol easily obtained through the diet and is present in tea, cocoa, vegetables, fruits, and cereals. Recent studies have shown that EC protects human health and exhibits prominent anti-oxidant and anti-inflammatory activities, enhances muscle performance, improves symptoms of cardiovascular and cerebrovascular diseases, prevents diabetes, and protects the nervous system. With the development of modern medical and biotechnology research, the mechanisms of action associated with EC toward various chronic diseases are becoming more apparent, and the pharmacological development and utilization of EC has been increasingly clarified. Currently, there is no comprehensive systematic introduction to the effects of EC and its mechanisms of action. This review presents the latest research progress and the role of EC in the prevention and treatment of various chronic diseases and its protective health effects and provides a theoretical basis for future research on EC.

Flavonoids and Reduction of Cardiovascular Disease (CVD) in Chronic Obstructive Pulmonary Disease (COPD)

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) and Cardiovascular Diseases (CV) Often Coexist. COPD and CVD are complex diseases characterized by a strict interaction between environment and genetic. The mechanisms linking these two diseases are complex, multifactorial and not entirely understood, influencing the therapeutic approach. COPD is characterized by several comorbidities, it hypothesized the treatment of cardiovascular co-morbidities that may reduce morbidity and mortality. Flavonoids are an important class of plant low molecular weight Secondary Metabolites (SMs). Convincing data from laboratory, epidemiological, and human clinical studies point the important effects on CVD risk prevention.

OBJECTIVE

This review aims to provide up-to-date information on the ability of Flavonoids to reduce the CVD risk.

CONCLUSION

Current studies support the potential of Flavonoids to prevent the risk of CVD. Well-designed clinical studies are suggested to evaluate advantages and limits of Flavonoids for managing CVD comorbidity in COPD.

Advances in drug therapy for mitochondrial diseases

Mitochondrial diseases are a group of clinically and genetically heterogeneous disorders driven by oxidative phosphorylation dysfunction of the mitochondrial respiratory chain which due to pathogenic mutations of mitochondrial DNA (mtDNA) or nuclear DNA (nDNA). Recent progress in molecular genetics and biochemical methodologies has provided a better understanding of the etiology and pathogenesis of mitochondrial diseases, and this has expanded the clinical spectrum of this conditions. But the treatment of mitochondrial diseases is largely symptomatic and thus does not significantly change the course of the disease. Few clinical trials have led to the design of drugs aiming at enhancing mitochondrial function or reversing the consequences of mitochondrial dysfunction which are now used in the clinical treatment of mitochondrial diseases. Several other drugs are currently being evaluated for clinical management of patients with mitochondrial diseases. In this review, the current status of treatments for mitochondrial diseases is described systematically, and newer potential treatment strategies for mitochondrial diseases are also discussed.

Effects of (-)-epicatechin on the time course of the expression of perilipins in a diet-induced model of nonalcoholic steatohepatitis

The existing treatments for nonalcoholic steatohepatitis (NASH) are not completely effective. The need for new alternatives without adverse effects and low cost, such as the flavonoid (-)-epicatechin (EC), which has beneficial effects on lipid metabolism and cardiovascular diseases, arises. The objective of this work was to analyze EC effects in the NASH induced by a Paigen-type diet (PD). Mice were administered with (1) normal chow and water, (2) PD + fructose 30% and (3) PD + fructose 30% + EC (1 mg/kg) per gavage during 9 weeks. At the end of each treatment, serum was collected for analysis of the biochemical profile and liver enzymes. The liver was collected for microscopic analysis and for the evaluation of the relative expression of Plin2, Plin3, CD36, adiponectin and UCP2. Results showed that EC reduced weight gain and decreased triglyceride (TG), low-density lipoprotein cholesterol, TG/high-density lipoprotein and the activity of liver enzymes (alanine aminotransferase and alkaline phosphatase), suggesting lower liver damage. The microscopic analysis showed less "balloonization" of the hepatocyte, small drops of lipids, less accumulation of collagen and infiltration of inflammatory cells as compared to nontreated group. Finally, a decrease in the expression of Plin 2 was observed. While CD36 decreased, adiponectin and UCP2 increased. In conclusion, EC improves the biochemical profile, the microscopic characteristics and protein expression. Therefore, it may be a possible therapeutic approach for NASH since it prevents the progression of the hepatic and metabolic damage induced by high-fat diets.

Flavonoids from Brazilian Cerrado: Biosynthesis, Chemical and Biological Profile

Flavonoids are highly bioactive compounds with very low toxicity, which makes them attractive starting points in drug discovery. This study aims to provide information on plant species containing flavonoids, which are found in the Brazilian Cerrado. First, we present the characterization and plant diversity with emphasis on the families of flavonoid-producing plants, and then we describe the phenylpropanoid pathway which represents the flavonoids’ main route biosynthesis—generally conserved in all species. Chemical structures and biological activities of flavonoids isolated from the Cerrado’s plant species are also described based on examples from the relevant literature studies. Finally, research on the biodiversity of the Cerrado biome should be encouraged, due to the discovery of new sources of flavonoids which can provide several benefits to human health and the possibility of developing new drugs by the pharmaceutical industry.

(-)-Epicatechin reduces adiposity in male offspring of obese rats

Objective:

To determine whether (-)-epicatechin (Epi) could decrease visceral adipose tissue and improve the metabolic profile of male offspring rats, after maternal obesity was induced by a high-fat diet (HFD).

Design:

Maternal obesity in albino Wistar rats was induced with a HFD, whereas male offspring were fed with chow diet throughout the study. Eight male offspring per group, from different litters, were randomly assigned to the experimental or to the control groups. In the experimental group, Epi was administered at a dose of 1 mg/kg of body weight to the male offspring twice daily for two weeks, beginning at postnatal day (PND).

Main measures:

Weight of visceral adipose tissue, adipocyte size, and several metabolic parameters.

Results:

Epi administration in the male offspring induced a significant decrease in the amount of visceral fat (11.61 g less, P < 0.05) and in the size of adipose cells (28% smaller, P < 0.01). Besides, Epi was able to decrease insulin, leptin, and Homeostasis Model Assessment -Insulin Resistance (HOMA-IR) (P < 0.05), as well as triglycerides, when the experimental group was compared to the untreated male offspring of obese rats (P < 0.01).

Conclusions:

Epi administration can reverse the negative effects that maternal obesity has on the male offspring. This could be because Epi reduces the amount of visceral fat and improves metabolic profile.

Looking beyond PGC-1α: emerging regulators of exercise-induced skeletal muscle mitochondrial biogenesis and their activation by dietary compounds

Despite its widespread acceptance as the "master regulator" of mitochondrial biogenesis (i.e., the expansion of the mitochondrial reticulum), peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1 alpha (PGC-1α) appears to be dispensable for the training-induced augmentation of skeletal muscle mitochondrial content and respiratory function. In fact, a number of regulatory proteins have emerged as important players in skeletal muscle mitochondrial biogenesis and many of these proteins share key attributes with PGC-1α. In an effort to move past the simplistic notion of a "master regulator" of mitochondrial biogenesis, we highlight the regulatory mechanisms by which nuclear factor erythroid 2-related factor 2 (Nrf2), estrogen-related receptor gamma (ERRγ), PPARβ, and leucine-rich pentatricopeptide repeat-containing protein (LRP130) may contribute to the control of skeletal muscle mitochondrial biogenesis. We also present evidence supporting/refuting the ability of sulforaphane, quercetin, and epicatechin to promote skeletal muscle mitochondrial biogenesis and their potential to augment mitochondrial training adaptations. Targeted activation of specific pathways by these compounds may allow for greater mechanistic insight into the molecular pathways controlling mitochondrial biogenesis in human skeletal muscle. Dietary activation of mitochondrial biogenesis may also be useful in clinical populations with basal reductions in mitochondrial protein content, enzyme activities, and/or respiratory function as well as individuals who exhibit a blunted skeletal muscle responsiveness to contractile activity. Novelty The existence of redundant pathways leading to mitochondrial biogenesis refutes the simplistic notion of a "master regulator" of mitochondrial biogenesis. Dietary activation of specific pathways may provide greater mechanistic insight into the exercise-induced mitochondrial biogenesis in human skeletal muscle.

Catechins enhance skeletal muscle performance

Muscle-related disorders, such as sarcopenia and cachexia, caused by aging and chronic diseases can lead to the loss of muscle mass and strength to different degrees, severely affecting human health. Globally, tea is one of the three most popular beverages, and its major active ingredient catechins have been reported to delay muscular atrophy and enhance movement. However, currently, there is no systematic review to elaborate its roles and the associated mechanisms. This article reviews the (1) functions and mechanisms of catechins in the differentiation of myogenic stem cells, biogenesis of mitochondria, synthesis and degradation of proteins, regulation of glucose level, and metabolism of lipids in muscle cells; and (2) effect of catechins on the blood vessels, bones, and nerves that are closely related to the skeletal muscles. Catechins could prevent, mitigate, delay, and even treat muscle-related disorders caused by aging and diseases.

(-)-Epicatechin stimulates mitochondrial biogenesis and cell growth in C2C12 myotubes via the G-protein coupled estrogen receptor

We have reported on the capacity of (-)-epicatechin ((-)-EPI) to stimulate mitochondrial biogenesis (MiB) in mouse skeletal muscle (SkM). However, the mechanisms mediating the effects of (-)-EPI are not fully understood. We previously identified a role of the G-protein coupled estrogen receptor (GPER) in modulating the vascular effects of (-)-EPI. We therefore tested the hypothesis that GPER mediates (at least in part) the stimulatory effects of (-)-EPI on MiB in SkM cells. As an in vitro model, we employed mouse SkM-derived C2C12 myoblasts differentiated into myotubes. Using confocal microscopy, we detected GPER at the cell surface and cytoplasm in C2C12 myotubes. Treatment with (-)-EPI (3 and 10μM) resulted in the stimulation of MiB as per increases in mitochondrial inner (MitoTracker Red FM fluorescence staining) and outer membrane (porin protein levels) markers, transcription factors involved in MiB stimulation (i.e., nuclear respiratory factor-2 [NRF-2] and mitochondrial transcription factor A [TFAM] protein levels) and citrate synthase (CS) activity levels. (-)-EPI-treated myotubes were longer and wider compared to vehicle-treated myotubes. The effects of (-)-EPI on myotube mitochondria and cell size were larger in magnitude to those observed with the GPER agonist G-1. The chemical blockade and down-regulation (siRNA) of GPER evidenced a partial and complete blockade of measured endpoints following (-)-EPI- or G-1-treatment, respectively. Altogether, results indicate that GPER is expressed in muscle cells and appears to mediate to a significant extent, the stimulatory effects of (-)-EPI on MiB. Thus, GPER activation may account for the stimulatory effects of (-)-EPI on SkM structure/function.

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.

Plant bioactives and redox signaling: (-)-Epicatechin as a paradigm

Polyphenols are bioactives claimed to be responsible for some of the health benefits provided by fruit and vegetables. It is currently accepted that the bioactivities of polyphenols can be mostly ascribed to their interactions with proteins and lipids. Such interactions can affect cell oxidant production and cell signaling, and explain in part the ability of polyphenols to promote health. EC can modulate redox sensitive signaling by: i) defining the extent of oxidant levels that can modify cell signaling, function, and fate, e.g. regulating enzymes that generate superoxide, hydrogen peroxide and nitric oxide; or ii) regulating the activation of transcription factors sensible to oxidants. The latter includes the regulation of the nuclear factor E2-related factor 2 (Nfr2) pathway, which in turn can promote the synthesis of antioxidant defenses, and of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway, which mediates the expression of oxidants generating enzymes, as well as proteins not involved in redox reactions. In summary, a significant amount of data vindicates the participation of EC in redox regulated signaling pathways. Progress in the understanding of the molecular mechanisms involved in EC biological actions will help to define recommendations in terms of which fruit and vegetables are healthier and the amounts necessary to provide health effects.

Therapies for mitochondrial diseases and current clinical trials

Mitochondrial diseases are a clinically and genetically heterogeneous group of disorders that result from dysfunction of the mitochondrial oxidative phosphorylation due to molecular defects in genes encoding mitochondrial proteins. Despite the advances in molecular and biochemical methodologies leading to better understanding of the etiology and mechanism of these diseases, there are still no satisfactory therapies available for mitochondrial disorders. Treatment for mitochondrial diseases remains largely symptomatic and does not significantly alter the course of the disease. Based on limited number of clinical trials, several agents aiming at enhancing mitochondrial function or treating the consequences of mitochondrial dysfunction have been used. Several agents are currently being evaluated for mitochondrial diseases. Therapeutic strategies for mitochondrial diseases include the use of agents enhancing electron transfer chain function (coenzyme Q₁₀, idebenone, riboflavin, dichloroacetate, and thiamine), agents acting as energy buffer (creatine), antioxidants (vitamin C, vitamin E, lipoic acid, cysteine donors, and EPI-743), amino acids restoring nitric oxide production (arginine and citrulline), cardiolipin protector (elamipretide), agents enhancing mitochondrial biogenesis (bezafibrate, epicatechin, and RTA 408), nucleotide bypass therapy, liver transplantation, and gene therapy. Although, there is a lack of curative therapies for mitochondrial disorders at the current time, the increased number of clinical research evaluating agents that target different aspects of mitochondrial dysfunction is promising and is expected to generate more therapeutic options for these diseases in the future.

Cocoa, Blood Pressure, and Vascular Function

Cardiovascular disease (CVD) represents the most common cause of death worldwide. The consumption of natural polyphenol-rich foods, and cocoa in particular, has been related to a reduced risk of CVD, including coronary heart disease and stroke. Intervention studies strongly suggest that cocoa exerts a beneficial impact on cardiovascular health, through the reduction of blood pressure (BP), improvement of vascular function, modulation of lipid and glucose metabolism, and reduction of platelet aggregation. These potentially beneficial effects have been shown in healthy subjects as well as in patients with risk factors (arterial hypertension, diabetes, and smoking) or established CVD (coronary heart disease or heart failure). Several potential mechanisms are supposed to be responsible for the positive effect of cocoa; among them activation of nitric oxide (NO) synthase, increased bioavailability of NO as well as antioxidant, and anti-inflammatory properties. It is the aim of this review to summarize the findings of cocoa and chocolate on BP and vascular function.

Browning effects of (-)-epicatechin on adipocytes and white adipose tissue

In this study, we demonstrate that (-)-epicatechin (Epi), a cacao flavanol, induces the browning of fat by promoting mitochondrial biogenesis, enhancing indicators of mitochondrial structure and function, increasing fatty acid metabolism and upregulating the expression of brown adipose tissue-specific proteins in a high-fat diet mouse model of obesity and in cultured human adipocytes. Epi treatment significantly improved mitochondrial function, as measured by citrate synthase activity, and also reduced protein acetylation of total and specific regulators in both adipose tissue and human adipocytes. Browning of fat via Epi was evidenced by the increased expression of key thermogenic genes, phosphorylation of upstream regulators of fatty acid oxidation, and reduced triglyceride levels. Properly designed clinical trials are needed to explore the potential of Epi as an agent that promotes the browning of fat.

Mitophagy Transcriptome: Mechanistic Insights into Polyphenol-Mediated Mitophagy

Mitochondria are important bioenergetic and signalling hubs critical for myriad cellular functions and homeostasis. Dysfunction in mitochondria is a central theme in aging and diseases. Mitophagy, a process whereby damaged mitochondria are selectively removed by autophagy, plays a key homeostatic role in mitochondrial quality control. Upregulation of mitophagy has shown to mitigate superfluous mitochondrial accumulation and toxicity to safeguard mitochondrial fitness. Hence, mitophagy is a viable target to promote longevity and prevent age-related pathologies. Current challenge in modulating mitophagy for cellular protection involves identification of physiological ways to activate the pathway. Till date, mitochondrial stress and toxins remain the most potent inducers of mitophagy. Polyphenols have recently been demonstrated to protect mitochondrial health by facilitating mitophagy, thus suggesting the exciting prospect of augmenting mitophagy through dietary intake. In this review, we will first discuss the different surveillance mechanisms responsible for the removal of damaged mitochondrial components, followed by highlighting the transcriptional regulatory mechanisms of mitophagy. Finally, we will review the functional connection between polyphenols and mitophagy and provide insight into the underlying mechanisms that potentially govern polyphenol-induced mitophagy.

Development of Therapeutics That Induce Mitochondrial Biogenesis for the Treatment of Acute and Chronic Degenerative Diseases

Mitochondria have various roles in cellular metabolism and homeostasis. Because mitochondrial dysfunction is associated with many acute and chronic degenerative diseases, mitochondrial biogenesis (MB) is a therapeutic target for treating such diseases. Here, we review the role of mitochondrial dysfunction in acute and chronic degenerative diseases and the cellular signaling pathways by which MB is induced. We then review existing work describing the development and application of drugs that induce MB in vitro and in vivo. In particular, we discuss natural products and modulators of transcription factors, kinases, cyclic nucleotides, and G protein-coupled receptors.

(-)-Epicatechin-induced recovery of mitochondria from simulated diabetes: Potential role of endothelial nitric oxide synthase

(-)-Epicatechin increases indicators associated with mitochondrial biogenesis in endothelial cells and myocardium. We investigated endothelial nitric oxide synthase involvement on (-)-epicatechin-induced increases in indicators associated with mitochondrial biogenesis in human coronary artery endothelial cells cultured in normal-glucose and high-glucose media, as well as to restore indicators of cardiac mitochondria from the effects of simulated diabetes. Here, we demonstrate the role of endothelial nitric oxide synthase on (-)-epicatechin-induced increases in mitochondrial proteins, transcription factors and sirtuin 1 under normal-glucose conditions. In simulated diabetes endothelial nitric oxide synthase function, mitochondrial function-associated and biogenesis-associated indicators were adversely impacted by high glucose, effects that were reverted by (-)-epicatechin. As an animal model of type 2 diabetes, 2-month old C57BL/6 mice were fed a high-fat diet for 16 weeks. Fasting and fed blood glucose levels were increased and NO plasma levels decreased. High-fat-diet-fed mice myocardium revealed endothelial nitric oxide synthase dysfunction, reduced mitochondrial activity and markers of mitochondrial biogenesis. The administration of 1 mg/kg (-)-epicatechin for 15 days by oral gavage shifted these endpoints towards control mice values. Results suggest that endothelial nitric oxide synthase mediates (-)-epicatechin-induced increases of indicators associated with mitochondrial biogenesis in endothelial cells. (-)-Epicatechin also counteracts the negative effects that high glucose or simulated type 2 diabetes has on endothelial nitric oxide synthase function.

Comparative effects of catechin, epicatechin and N-Ω-nitroarginine on quinolinic acid-induced oxidative stress in rat striatum slices

The aim of this work was to compare the effects of catechin (CAT), epicatechin (EPI) and N-ω-l-nitroarginine (L-NARG) on different endpoints of oxidative stress induced by quinolinic acid (QUIN) in a simple tissue preparation, rat striatal slices - with particular emphasis in the glutathione system - in order to provide revealing information on the antioxidant efficacy of these agents in an excitotoxic model.

METHODS

Rat striatal slices were incubated for 1h in the presence of 100 μM QUIN and/or 85 μM CAT or EPI, or 100 μM L-NARG. Lipid peroxidation (LP) and the levels of reduced and oxidized glutathione (GSH and GSSG) were determined.

RESULTS

The three agents tested completely blocked the QUIN-induced lipid peroxidation and recovered the QUIN-induced altered GSH/GSSG balance. No statistical differences were detected among the protective effects exerted by these antioxidants, suggesting similar efficacy and common antioxidant mechanisms. The antioxidant properties exhibited by these molecules on the excitotoxic model tested herein support an active role of glutathione and prompt their use as therapeutic tools in models of neurodegenerative disorders.

The effects of (-)-epicatechin on endothelial cells involve the G protein-coupled estrogen receptor (GPER)

We have provided evidence that the stimulatory effects of (-)-epicatechin ((-)-EPI) on endothelial cell nitric oxide (NO) production may involve the participation of a cell-surface receptor. Thus far, such entity(ies) has not been fully elucidated. The G protein-coupled estrogen receptor (GPER) is a cell-surface receptor that has been linked to protective effects on the cardiovascular system and activation of intracellular signaling pathways (including NO production) similar to those reported with (-)-EPI. In bovine coronary artery endothelial cells (BCAEC) by the use of confocal imaging, we evidence the presence of GPER at the cell-surface and on F-actin filaments. Using in silico studies we document the favorable binding mode between (-)-EPI and GPER. Such binding is comparable to that of the GPER agonist, G1. By the use of selective blockers, we demonstrate that the activation of ERK 1/2 and CaMKII by (-)-EPI is dependent on the GPER/c-SRC/EGFR axis mimicking those effects noted with G1. We also evidence by the use of siRNA the role that GPER has on mediating ERK1/2 activation by (-)-EPI. GPER appears to be coupled to a non Gαi/o or Gαs, protein subtype. To extrapolate our findings to an ex vivo model, we employed phenylephrine pre-contracted aortic rings evidencing that (-)-EPI can mediate vasodilation through GPER activation. In conclusion, we provide evidence that suggests the GPER as a potential mediator of (-)-EPI effects and highlights the important role that GPER may have on cardiovascular system protection.

Cranberry flavonoids prevent toxic rat liver mitochondrial damage in vivo and scavenge free radicals in vitro

The present study was undertaken for further elucidation of the mechanisms of flavonoid biological activity, focusing on the antioxidative and protective effects of cranberry flavonoids in free radical-generating systems and those on mitochondrial ultrastructure during carbon tetrachloride-induced rat intoxication. Treatment of rats with cranberry flavonoids (7 mg/kg) during chronic carbon tetrachloride-induced intoxication led to prevention of mitochondrial damage, including fragmentation, rupture and local loss of the outer mitochondrial membrane. In radical-generating systems, cranberry flavonoids effectively scavenged nitric oxide (IC50  = 4.4 ± 0.4 µg/ml), superoxide anion radicals (IC50  = 2.8 ± 0.3 µg/ml) and hydroxyl radicals (IC50  = 53 ± 4 µg/ml). The IC50 for reduction of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) was 2.2 ± 0.3 µg/ml. Flavonoids prevented to some extent lipid peroxidation in liposomal membranes and glutathione oxidation in erythrocytes treated with UV irradiation or organic hydroperoxides as well as decreased the rigidity of the outer leaflet of the liposomal membranes. The hepatoprotective potential of cranberry flavonoids could be due to specific prevention of rat liver mitochondrial damage. The mitochondria-addressed effects of flavonoids might be related both to radical-scavenging properties and modulation of various mitochondrial events.

Direct effects of (-)-epicatechin and procyanidin B2 on the respiration of rat heart mitochondria

Flavonol (−)-epicatechin and its derived dimer procyanidin B2, present in high amounts in cocoa products, have been shown to exert beneficial effects on the heart and cardiovascular system; however, their mechanism of action has not been fully elucidated. We studied effects of (−)-epicatechin and procyanidin B2 on the oxidative phosphorylation of isolated rat heart mitochondria. (−)-Epicatechin and procyanidin B2 had stimulating effect (up to 30% compared to control) on substrate-driven (State 2) mitochondrial respiration. Their effect was dependent on the respiratory substrates used. (−)-Epicatechin at higher concentrations (from 0.27 µg/mL) significantly decreased (up to 15%) substrate- and ADP-driven (State 3) mitochondrial respiration in case of pyruvate and malate oxidation only. Procyanidin B2 (0.7–17.9 ng/mL) inhibited State 3 respiration rate up to 19%, the most profound effect being expressed with succinate as the substrate. (−)-Epicatechin at concentrations of 0.23 µg/mL and 0.46 µg/mL prevented loss of the cytochrome c from mitochondria when substrate was succinate, supporting the evidence of membrane stabilizing properties of this flavonol. Thus, both (−)-epicatechin and procyanidin B2 directly influenced mitochondrial functions and the observed effects could help to explain cardiometabolic risk reduction ascribed to the consumption of modest amounts of cocoa products.

Potential compounds for the treatment of mitochondrial disease

INTRODUCTION

Mitochondrial diseases are a group of heterogeneous disorders for which no curative therapy is currently available. Several drugs are currently being pursued as candidates to correct the underlying biochemistry that causes mitochondrial dysfunction.

SOURCES OF DATA

A systematic review of pharmacological therapeutics tested using in vitro, in vivo models and clinical trials. Results presented from database searches undertaken to ascertain compounds currently being pioneered to treat mitochondrial disease.

AREAS OF AGREEMENT

Previous clinical research has been hindered by poorly designed trials that have shown some evidence in enhancing mitochondrial function but without significant results.

AREAS OF CONTROVERSY

Several compounds under investigation display poor pharmacokinetic profiles or numerous off target effects.

GROWING POINTS

Drug development teams should continue to screen existing and novel compound libraries for therapeutics that can enhance mitochondrial function. Therapies for mitochondrial disorders could hold potential cures for a myriad of other ailments associated with mitochondrial dysfunction such as neurodegenerative diseases.