Cardiovascular

Loss of cardiac macroautophagy/autophagy impairs heart function, and evidence accumulates that an increased autophagic flux may protect against cardiovascular disease. We therefore tested the protective capacity of the natural autophagy inducer spermidine in animal models of aging and hypertension, which both represent major risk factors for the development of cardiovascular disease. Dietary spermidine elicits cardioprotective effects in aged mice through enhancing cardiac autophagy and mitophagy. In salt-sensitive rats, spermidine supplementation also delays the development of hypertensive heart disease, coinciding with reduced arterial blood pressure. The high blood pressure-lowering effect likely results from improved global arginine bioavailability and protection from hypertension-associated renal damage. The polyamine spermidine is naturally present in human diets, though to a varying amount depending on food type and preparation. In humans, high dietary spermidine intake correlates with reduced blood pressure and decreased risk of cardiovascular disease and related death. Altogether, spermidine represents a cardio- and vascular-protective autophagy inducer that can be readily integrated in common diets.

Recent and exciting in vivo studies show that supplementation with the polyamine spermidine (Spd) is cardioprotective and prolongs lifespan in both mice and humans. The mechanisms behind Spd-induced cardioprotection are supposed to involve Spd-evoked stimulation of autophagy, mitophagy and mitochondrial respiration and improved the mechano-elastical function of cardiomyocytes. Although cellular uptake of Spd was not characterized, these results suggest that Spd is imported by the cardiomyocytes and acts intracellularly. In the light of these new and thrilling data, we discuss in the present review cellular polyamine import with a special focus on mechanisms that may be relevant for Spd uptake by electrically excitable cells such as cardiomyocytes.

Aging is associated with an increased risk of cardiovascular disease and death. Here we show that oral supplementation of the natural polyamine spermidine extends the lifespan of mice and exerts cardioprotective effects, reducing cardiac hypertrophy and preserving diastolic function in old mice. Spermidine feeding enhanced cardiac autophagy, mitophagy and mitochondrial respiration, and it also improved the mechano-elastical properties of cardiomyocytes in vivo, coinciding with increased titin phosphorylation and suppressed subclinical inflammation. Spermidine feeding failed to provide cardioprotection in mice that lack the autophagy-related protein Atg5 in cardiomyocytes. In Dahl salt-sensitive rats that were fed a high-salt diet, a model for hypertensioninduced congestive heart failure, spermidine feeding reduced systemic blood pressure, increased titin phosphorylation and prevented cardiac hypertrophy and a decline in diastolic function, thus delaying the progression to heart failure. In humans, high levels of dietary spermidine, as assessed from food questionnaires, correlated with reduced blood pressure and a lower incidence of cardiovascular disease. Our results suggest a new and feasible strategy for the protection from cardiovascular disease.

the cardioprotective benefits of oral spermidine are dependent on autophagy

Stringent dietary adjustments, albeit effective in delaying ageing, are not attractive to the majority of people. Thus, pharmaceuticals or natural substances that mimic caloric restriction, like spermidine, are emerging as an alternative and feasible strategy to promote healthy ageing.

A recent study published in Nature Medicine reports that dietary supplementation with spermidine, a natural polyamine, extends life span and reverses aging-associated cardiac dysfunction in mice through induction of autophagy. Similar protective effects of spermidine on human cardiovascular health were also suggested by epidemiological studies.1

FWGE , a product of industrial fermentation of wheat germ with a standardized content of benzoquinone and plant flavonoids, has been tested as an anti-cancer and immunomodulatory dietary supplement. Proposed mechanisms include anti-oxidant and anti-inflammatory actions. This study has determined whether these actions of FWGE may also be useful in the treatment of cardiovascular diseases. Two experimental rat models of cardiovascular remodeling were used in this project: the deoxycorticosterone acetate (DOCA)-salt-induced model of chronic hypertension (study I) and a high-carbohydrate/high-fat dietinduced model producing chronic symptoms of the metabolic syndrome and its associated cardiovascular complications (study II). Our results in these rat models of hypertension and diet-induced obesity show that treatment with FWGE improved cardiac function, decreased macrophage infiltration resulting in decreased collagen deposition in the ventricular myocardium, reversed an increased stiffness of the left ventricle in the diseased hearts and attenuated increased plasma malondialdehyde concentrations. In addition to the changes in the heart, FWGE reversed glucose intolerance, normalized systolic blood pressure and decreased visceral fat deposition in rats fed a high-fat/high-carbohydrate diet. In conclusion, the fermented wheat germ extract FWGE has a potential role in attenuating chronic hypertension, diabetes or metabolic syndrome-induced cardiovascular symptoms along with metabolic abnormalities such as glucose tolerance and obesity.

A recent study shows that spermidine has beneficial effects on health and lifespan in mice, and that these effects are the result of improved cardiovascular function. Similar effects of spermidine on humans are supported by epidemiological studies.

Aging is the most important risk factor for cardiovascular disease (CVD). Slowing or reversing the physiological impact of heart aging may reduce morbidity and mortality associated with age-related CVD. The polyamines, spermine (SP) and spermidine (SPD) are essential for cell growth, differentiation and apoptosis, and levels of both decline with age. To explore the effects of these polyamines on heart aging, we administered SP or SPD intraperitoneally to 22- to 24-month-old rats for 6 weeks. Both treatments reversed and inhibited age-related myocardial morphology alterations, myocardial fibrosis, and cell apoptosis. Using combined proteomics and metabolomics analyses, we identified proteins and metabolites up- or downregulated by SP and SPD in aging rat hearts. SP upregulated 51 proteins and 28 metabolites while downregulating 80 proteins and 29 metabolites. SPD upregulated 44 proteins and 24 metabolites and downregulated 84 proteins and 176 metabolites. These molecules were mainly associated with immune responses, blood coagulation, lipid metabolism, and glutathione metabolism pathways. Our study provides novel molecular information on the cardioprotective effects of polyamines in the aging heart, and supports the notion that SP and SPD are potential clinical therapeutics targeting heart disease.

Arterial aging, characterized by stiffening of large elastic arteries and the development of arterial endothelial dysfunction, increases cardiovascular disease (CVD) risk. We tested the hypothesis that spermidine, a nutrient associated with the anti-aging process autophagy, would improve arterial aging. Aortic pulse wave velocity (aPWV), a measure of arterial stiffness, was ~20% greater in old (O, 28 months) compared with young C57BL6 mice (Y, 4 months, P < 0.05). Arterial endothelium-dependent dilation (EDD), a measure of endothelial function, was ~25% lower in O (P < 0.05 vs. Y) due to reduced nitric oxide (NO) bioavailability. These impairments were associated with greater arterial oxidative stress (nitrotyrosine), superoxide production, and protein cross-linking (advanced glycation end-products, AGEs) in O (all P < 0.05). Spermidine supplementation normalized aPWV, restored NO-mediated EDD and reduced nitrotyrosine, superoxide, AGEs and collagen in O. These effects of spermidine were associated with enhanced arterial expression of autophagy markers, and in vitro experiments demonstrated that vascular protection by spermidine was autophagy-dependent. Our results indicate that spermidine exerts a potent anti-aging influence on arteries by increasing NO bioavailability, reducing oxidative stress, modifying structural factors and enhancing autophagy. Spermidine may be a promising nutraceutical treatment for arterial aging and prevention of age-associated CVD.