Resveratrol and SIRT1 Activators for the Treatment of Aging and Age-Related Diseases

Reduced calorie intake is a religious and medical practice known since very old times, but its direct influence on life span in all organisms, included humans, has been demonstrated in the modern era. Not only periodic fasting, but also natural or synthetic compounds that mimic this phenomenon are growing to slow aging and the onset of chronic morbidities. Resveratrol (RSV), a plant polyphenol, is an elixir of longevity for simple organisms and preclinical rodent models even if a beneficial role in humans is still debated. Its main rejuvenating mechanism copes with the activation of specific longevity genes called sirtuins. Among seven known mammalian sirtuins, sirtuin 1 is the most studied. This pleiotropic nicotinamide adenine dinucleotide (NAD)-based deacetylase maintains longevity by removing acetyl group in nuclear histones, transcription factors, and other DNA repairing proteins. Actually, an exciting challenge is to discover and test novel sirtuin 1 activators to extend life span and to treat age-associated disabilities. This chapter updates on the antiaging effect of RSV and sirtuin 1 activators in experimental animals and in humans. Finally, pros and cons on RSV analogues and sirtuin 1 activators tested in preclinical and clinical trials to hamper neurological deficit, cardiovascular complications, diabetes, bone and muscle deterioration, and cancer are discussed

Endoplasmic Reticulum Stress and Apoptosis Triggered by Sub-Chronic Lead Exposure in Mice Spleen: a Histopathological Study

Lead (Pb) is an environmental oncogenic metal that induces immunotoxicity and anaemia. Emerging evidence has linked Pb toxicity with endoplasmic reticulum-driven apoptosis and autophagy. Glucose-regulated protein of 78 kDa (Grp78 or binding immunoglobulin protein (BiP)), a master endoplasmic reticulum chaperone, drives macrophage activation and regulates protein folding and calcium flux in response to heavy metals. The spleen may be involved in Pb poisoning due to its crucial role in erythrocatheresis and immune response, although there are no data to support this theory. Here, we found haematic and histopathological changes in the spleen of mice exposed to medium doses of Pb acetate (200 ppm-1 mM) in drinking water for 45 days. Pb deposition was also detected in organs such as the liver, kidney, brain, bone, blood and faeces, indicating an accumulation of this metal despite relatively short exposure time. Blood Pb content (BBL) reached 21.6 μg/dL; echinocytes and poikilocytes were found in Pb smears of treated group. Inside the spleen, higher Fe(II) and Fe(III) deposits inside macrophages were observed. Grp78 immunostaining, weakly expressed in spleen cells of control mice, after Pb exposure was specifically restricted to macrophages and megakaryocytes of the marginal zone of red pulp. Furthermore, Pb exposure induced superoxide dismutase 1 (SOD1) expression, cleaved caspase-3 and p62/SQSTM1, consistent with oxidative stress, apoptosis and dysregulated autophagy in spleen compartments. We suggest that even at a middle dose, oral Pb intake induces oxidant iron deposition in the spleen and that this may trigger sustained Grp78 redistribution to cells, thus leading to oxidative and autophagy dysfunction as early local reactions to this dangerous metal

Hepatic Macrosteatosis Is Partially Converted to Microsteatosis by Melatonin Supplementation in ob/ob Mice Non-Alcoholic Fatty Liver Disease

Obesity is a common risk factor for non-alcoholic fatty liver disease (NAFLD). Currently, there are no specific treatments against NAFLD. Thus, examining any molecule with potential benefits against this condition emerged melatonin as a molecule that influences metabolic dysfunctions. The aim of this study was to determine whether melatonin would function against NAFDL, studying morphological, ultrastuctural and metabolic markers that characterize the liver of ob/ob mice

Mitophagy in human diseases

Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post‐mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age‐related neurodegener-ative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.This research was funded by the Spanish “Ministerio de Ciencia, Innovación y Universidades” (MICIU) and ERDF/FEDER funds, grant number RTI2018-093864-B-I00, and the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement 721236-TREATMENT to M.M

Melatonin limits adaptive ER stress and hepatosteatosis in leptin-deficient mice

Non alcoholic fatty liver disease (NAFLD) impacts on about 30% of the population in industrialized countries, associated to the metabolic syndrome may be reversible or dramatically evolve into cirrhosis or hepatocellular cancer (Wree et al., 2011). Leptin-deficient homozygous mice (ob/ob) represent a well-known animal model to study obesity, associated with overweight, liver steatosis and insulinresistance. Recently ER stress has been reported to contribute to hepatic steatosis and cell damage called lipoapoptosis (Flamment et al., 2010). Melatonin, the main pineal indoleamine, has been demonstrated to be useful to limit adipogenesis in many metabolic clinical conditions (de Luxan-Delgado et al., 2014). Therefore major aims of the present study were: 1.To localize ER stress, energy homeostasis and hypoxia markers in the liver of ob/ob mice receiving or not melatonin in drinking water at 100 mg/ kg/day for 8 weeks; 2.To characterize hepatic steatosis and quantify macrosteatosis in different experimental groups. C57BL6 mice treated or not with melatonin were used as controls. Remarkably in ob/ob mice receiving melatonin, macrosteatosis, periportal GRP78 staining decreased while beta catenin became basolateral into hepatocytes. Furthermore melatonin limited nuclear CHOP staining, a recognized index of major sensitivity to apoptosis, but stimulated p62/SQSTM1 signal, involved in reducing lipogenesis. Moreover by TEM analysis, we visualized in ob/ob mice liver mitochondria that displayed more cristae and strict RER adhesion after melatonin intake. In conclusion, our morphological analysis suggests that melatonin might ameliorate NAFLD by anti-oxidative and ER stress modulatory abilities in obese mice

Metabolic syndrome alters inflammatory and membrane markers expression in human atrium cardiomyocytes

Metabolic syndrome (MetS) is a cluster of various clinical cardiovascular risk factor and causes metabolic and structural cardiomyocytes damage. Our previous study showed that MetS increases cardiomyocytes stress chaperones (1). In this work we aimed to investigate if patients with MetS showed alteration of surface, mitochondria and inflammatory markers in atrium cardiomyocytes. Atrium samples from MetS patients with stable angina, undergoing coronary artery bypass graft surgery were used. Samples from matched age subjects without MetS and no smokers, undergoing cardiac surgery for other reasons, were used as controls. The samples, obtained before cardioplegia, were fixed and processed for Caveolin 1 (Cav1), MURC, Citrate Synthase (CS), SIRT3, SOD1, IL6-10, iNOS and eNOS by immunohistochemistry. Compared to controls, in cardiomyocytes from MetS patients decreased the expression of Cav1, MURC, SIRT3, IL10 and eNOS, whereas increased the expression of CS, SOD1, IL6, iNOS. Cardiomyocytes from MetS patients present an evident inflammatory chronic state, that alters the Cav1-MURC expression. These alterations could reduce the exchange functions of sarcolemma so impairing the contractile capacity associated with mitochondrial impairment. We speculate that these damages could induce antioxidant SOD1 over-expression to rescue the cells. All these results, first from human heart, suggest that MetS induces severe enzymatic disregulation in atrium cardiomyocytes that may predispose to cardiac surgery complications

Metabolic syndrome and melatonin: a tool for prevent obesity-associated abnormalities

Obesity is a common and complex health problem, which impacts crucial organs; it is also considered an independent risk factor for chronic kidney disease [1]. Few studies have analyzed the consequence of obesity in the renal proximal convoluted tubules, the major section of the reabsorptive process. To best perform its functions, the kidney requires energy primarily provided by mitochondria. Melatonin, indoleamine and antioxidant, has been identified in mitochondria, and overwhelming evidence has documented its essential role in the prevention of oxidative mitochondrial damage [2]. Herein, we evaluated the mechanism(s) of mitochondrial alterations in an animal model of obesity (ob/ob mice) and describe the beneficial effects of melatonin treatment on mitochondria morphology and dynamics as influenced by mitofusin- 2 and the intrinsic apoptotic cascade. Melatonin was dissolved in 1% ethanol and added to the drinking water from postnatal week 5 to 13; the calculated dose of melatonin intake was 100 mg/kg body weight/day. Compared to control mice, obesity-induced morphological alterations were apparent in the proximal tubules; the tubules contained round mitochondria with irregular, short cristae and the lining cells excited and elevated apoptotic index. Melatonin supplementation in obese mice changed mitochondria shape and cristae organization of proximal tubules, enhanced mitofusin-2 expression, which in turn modulated the progression of the mitochondria- driven intrinsic apoptotic pathway. The results aid in reducing renal failure. The melatonin-mediated changes probably suggest the use of melatonin to protect against renal morphological damage and dysfunction during metabolic disease

Stress proteins in experimental nephrotoxicity: a ten year experience

Heat shock proteins and glucose­regulated proteins represent an extraordinary mechanism of defense induced in the kidney by chemicals or drugs and essential to survive. Here we resume our experience on the presence and regulation of stress proteins into acute and chronic nephrotoxic models in rodents and in vitro. In acute renal damage, induced in rats by a single injection of inorganic mercury, stress proteins enhanced in a dose-dependent manner to recover cytoskeleton and mitochondria and maintain nuclear activity. When we pre-treated mercury injected-rats with antioxidant melatonin or with bimoclomol, a stress proteins-coinducer, stress proteins expression was modulated together with tubular recovery. Similar data were obtained in ischemia-reperfusion in rats treated with stannous chloride, that provided cytoprotection stimulating heme oxygenase induction. During nephrotoxicity induced by administration of cyclosporine A at therapeutic dosage for 1-2 months, stress protein overexpression well correlated with oxidative and cell death, but decreased if we counteracted renal damage using antioxidants. In aluminium intoxication through drinking water for 3-6 months, we detected a time-dependent stress response in the rat kidney that was organ specific and different from the liver. In vitro studies on rat tubular proximal cells exposed to heavy metals demonstrated that stress protein expression was related to peculiar mechanisms of action of each metal. In conclusion, experimental studies on the renal chaperones can greatly contribute to understand their role, and agents able to modulate the stress response might be considered promising therapeutic tools to reduce nephrotoxicity

Protective effects of melatonin against nicotine-induced oxidative damage of kidney

Several studies demonstrated that melatonin treatment prevents tissue damage in various models of oxidative stress (1). Experiments have shown that chronic nicotine administration caused oxidant damage in various organs by increasing lipid peroxidation products and decreasing the activity of endogenous antioxidants (2). The aim of this study was to investigate the effects of melatonin treatment on nicotine-induced oxidative changes in rat kidney and to explore the possible mechanisms of action. Three groups of rats were used as controls (the first without treatment, the second with melatonin alone and the third with nicotine alone). The last group of rats was orally treated with nicotine and melatonin for 28 days. Morphological changes in kidney were evaluated by histological procedures and immunohistochemical analysis using inflammation (NFkB and IL-6) and oxidative stress (SOD, CAT and iNOS) markers. Experiments performed demonstrated that nicotine administration increases inflammation and oxidative stress. Melatonin has a protective effect against nicotine kidney toxicity through an inhibition of inflammation and consequent oxidative damage. These data suggest that melatonin supplementation effectively counteracts the deleterious effect of chronic nicotine administration on kidney and attenuates oxidative damage possibly by its anti-inflammatory and antioxidant effects.This work was supported by grants from University of Brescia (EX 60%)