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Calorie restriction (CR) refers to a reduction of calorie intake without compromising essential nutrients to avoid malnutrition. CR has been established as a non-genetic method of altering longevity and attenuating biological changes associated with aging. Aging is also an important risk factor for erectile dysfunction. The aim of this study was to examine whether CR diet can reverse the age-related alterations of erectile tissue in the aged rat. Four groups of rats were used: young rats (7 months) + ad libitum, aged rats (22 months) + ad libitum, young rats + CR diet, and aged rats + CR diet. The ad libitum group had free access to both food and water, and CR groups were fed 60% of the food intake of their ad libitum littermates, starting from 6 weeks before sacrifice. The penis was harvested and stained with antibodies to von Willebrand factor, smooth muscle α-actin, platelet-derived growth factor receptor-β, phospho-eNOS, nNOS, and neurofilament. We also performed Masson trichrome staining and TUNEL assay. The blood samples were collected for the measurement of serum total testosterone level. The contents of endothelial cells, smooth muscle cells, pericytes, and neuronal cells as well as serum testosterone levels were significantly lower in the penis of aged rats than in their young littermates. CR significantly restored cavernous endothelial cells, smooth muscle cells, pericytes, and neuronal cell contents and decreased cavernous endothelial cell apoptosis and fibrosis in both young and aged rats. CR also increased serum testosterone level in aged rats, but not in young rats. CR successfully improved age-related derangements in penile neurovascular structures and hormonal disturbance. Along with a variety of lifestyle modifications, our study gave us a scientific rationale for CR as a non-pharmaceutical strategy to reprogram damaged erectile tissue toward neurovascular repair in aged men., (© 2017 American Society of Andrology and European Academy of Andrology.)

Background: Sarcopenia, the aging-related deterioration of skeletal muscle, is a disease that is directly associated with quality of life. Given the trend of an increasing aging population worldwide, the prevention of aging-related diseases such as sarcopenia has become ever more important and urgent., Objective: To identify potential therapeutic targets for this disease., Methods: we used a bioinformatics approach of combining cDNA microarray analysis and protein-protein interaction prediction., Results: We found 673 significant differentially expressed genes (128 upregulated and 545 downregulated) in sarcopenia patients of over 60 years of age. Most of the upregulated genes were involved in metabolic processes such as the PPAR signaling pathway. In particular, FABP4, PLIN1, and ADIPOQ were related to fatty acid and lipid metabolism. Some of the downregulated genes were located in the mitochondrial matrix. Additionally, through the protein interaction network analysis, we found two key molecules (MAP1LC3B and HSP90AB1) that were associated with autophagy., Conclusions: These results suggest that mitochondrial dysfunction and lipid metabolism are associated with sarcopenia., Competing Interests: No conflict of interest declared by authors

The extension of both median and maximum lifespan and the suppression of age-related diseases in laboratory animals by reduced food intake, i.e., calorie restriction (CR) are regarded as hallmarks of CR's anti-aging action. The diverse efficacy of CR to counteract aging effects and its experimental reproducibility has made it the gold standard of many aging intervention studies of recent years. Although CR originally was used as a tool to perturb the aging process of laboratory animals as to uncover clues of underlying mechanisms of aging processes, current CR research interests have shifted to the retardation of aging-related functional decline and the prevention of age-related diseases. Advances in CR research on non-human primates and recent endeavors using human subjects offer a promising outlook for CR's beneficial effects in healthy human aging. In this review, several major issues related to CR's anti-aging mechanisms are discussed by highlighting the importance of modulating deleterious chronic inflammation at molecular levels and the impact of epigenetic chromatin and histone modifications by CR at the ultimate control sites of gene expression. The recent research on rapamycin as a CR mimetic is summarized and a brief description of intermittent feeding patterns is reviewed in comparison to the CR effect., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Aging is a biological process characterized by time-dependent functional declines that are influenced by changes in redox status and by oxidative stress-induced inflammatory reactions. An organism's pro-inflammatory status may underlie the aging process and age-related diseases. In this review, we explore the molecular basis of low-grade, unresolved, subclinical inflammation as a major risk factor for exacerbating the aging process and age-related diseases. We focus on the redox-sensitive transcription factors, NF-κB and FOXO, which play essential roles in the expression of pro-inflammatory mediators and anti-oxidant enzymes, respectively. Major players in molecular inflammation are discussed with respect to the age-related up-regulation of pro-inflammatory cytokines and adhesion molecules, cyclo-oxygenase-2, lipoxygenase, and inducible nitric oxide synthase. The molecular inflammation hypothesis proposed by our laboratory is briefly described to give further molecular insights into the intricate interplay among redox balance, pro-inflammatory gene activation, and chronic age-related inflammatory diseases. The final section discusses calorie restriction as an aging-retarding intervention that also exhibits extraordinarily effective anti-inflammatory activity by modulating GSH redox, NF-κB, SIRT1, PPARs, and FOXOs.

Objective: To compare the effect of short-term calorie restriction (CR) on aging with that of already known long-term CR, the anti-inflammatory efficacy of 10-day CR was explored in aged rat kidney., Treatment: Two different age groups, 6 months (young) and 24 months (old) were used. In the old group, one sub-group was control, fed ad libitum (AL) and the other was fed CR for 10 days with 40 % of the food intake of the AL subgroup (n = 5)., Methods: Reactive species (RS), lipid peroxides and COX-2 activity were measured. The activities of proinflammatory transcription factors NF-kB and AP-1 were measured by electro-mobility shift assay (EMSA). Upstream signaling cascades of NF-kB and AP-1 as well as proinflammatory gene expression were detected by Western blot., Results: 10-day CR suppressed RS, lipid peroxides, and COX-2 activity in aged rat kidney. CR also inhibited upstream signaling cascades and DNA binding activity of NF-kB and AP-1, and thioredoxin/Ref-1 pathway. CR blocked expression of NF-kB-and AP-1-responsive gene COX-2, iNOS, VCAM-1 and ICAM-1., Conclusions: We report for the first time that 10-day CR can attenuate the altered signaling transduction for inflammatory processes which is mediated through RS-induced NF-kB and AP-1 in aged kidney.

In attempt to meet tissue demands for proper blood flow, the vasculature alters its structure, simultaneously responding to both physical and chemical stresses. Substantial information has emerged in this field of study, particularly concerning the roles of the endothelium and smooth muscle cells in relation to signaling pathways for mechanotransduction. As a first line of defense upon exposure to various stressors, the endothelium and smooth muscle cells respond with adaptive cellular modifications. One prime example of these modifications is the cellular response to oxidative stress as evidenced by accumulated data. A recent proposal of the inflammatory hypothesis of vascular aging emphasized that stress-induced vascular aging may be the primary event that underlies the general aging phenomenon of systemic dysfunction.

Several studies have demonstrated that inhibitors of cyclooxygenase (COX) attenuate various neuronal injuries and age-dependent demented conditions. From these findings, we proposed to test the effect of age on COX activity and its possible suppression by the antiaging action of dietary restriction in the rat brain. The status of reactive oxygen species (ROS) was also assessed to correlate with COX activity to delineate the underlying mechanism of the altered COX activity during aging. These results showed that COX activity significantly increased in 24-month-old rats compared with 6-month-old rats in an ad libitum group. Interestingly, mRNA and protein levels of COX-2 showed little corresponding age-related change. The formation of ROS was found to increase gradually with age in ad libitum fed rats. However, dietary restriction suppressed the increase at the age of 24 months. To substantiate the relationship between ROS and COX activity when the rats were 24 months of age, we conducted in vitro experiments with a C6 glioma cell line. Together, it is concluded that increased COX activity with age is due to the activation of COX catalytic reaction by ROS without increased gene expression of COX-2 and that it is related to the increased pro-oxidant status in aged rats.

Cyclooxygenase (COX) is the key rate-limiting enzyme in the prostaglandin synthetic pathway. Two isoforms of COX have been identified: a constitutive COX-1 and an inducible COX-2, which is activated in response to various stimuli. We investigated the changes of COX-1 and COX-2 in rat heart during aging. We measured the age-related changes in the mRNA and protein levels of COX by using reverse-transcription polymerase chain reaction and Western blotting, respectively. COX-2 mRNA and protein levels increased with age, whereas those of COX-1 showed no change. The COX activity determined by prostaglandin E(2) production increased with age. Because the COX-catalyzed arachidonate cascade is an important source of reactive oxygen species (ROS) generation, changes in ROS generation and lipid peroxidation were also assessed. The amount of ROS generated by the COX pathway increased with age, as did the total ROS generation and lipid peroxidation. These results show that COX-2 activity increases with age, partially because of elevated transcriptional expression and protein content, and they suggest that increased COX-2 can play a role in oxidative alterations in the aged heart.

Hardly an aspect of aging is more important than an organism's ability to withstand stress or to resist both internally and externally imposed insults. We know that as organisms loose their ability to resist these insults, aged organisms suffer more than the young. Therefore, a prime strategy for an organism's survival has been the evolutionarily adapted defense systems that guard against insult. For better survivability, an organism's defense system must be maximized to its full effect through well-coordinated networks of diverse biologically responsive elements. Although terms like stress, resistance, and adaptability have long been used in biology, they remain mechanistically and quantitatively poorly defined. In a gerontological context, stress resistance or susceptibility are often discussed in association with an organism's vulnerability to disease and age-related damage. However, to date, there is no clear molecular delineation of cellular and molecular mechanisms for such complex biological phenomena. The life-prolonging action of caloric restriction (CR) seems to offer an excellent opportunity for investigating the interrelationship between stress and the aging process. As an omnipotent intervention, CR provides a unique opportunity to probe the organism's ability to withstand age-related stress as a survival strategy. In this context, the antiaging action of CR can be viewed as "nutritional stress," because the organism's reduced caloric intake seems to be a stimulatory metabolic response for survivability. Recent gerontologic research has provided sufficient experimental data supporting this antiaging property of CR, of which several pertinent, key examples are discussed below.

Current evidence strongly indicates that reactive oxygen species (ROS) and reactive nitrogen species (RNS) are widely implicated in the inflammatory process. However, mechanistic information is not readily available on the extent to which ROS/RNS contributes to the proinflammatory states of the aging process. The involvement of the underlying inflammation during the aging process and the molecular delineation of anti-inflammatory action of calorie restriction (CR) is described. Age-related upregulations of NF-kappaB, IL-beta, IL-6, TNFalpha, cyclooxygenase-2, and inducible NO synthase are all attenuated by CR. The suppression of the NF-kappaB activation was accomplished by blocking the dissociation of inhibitory IkappaBalpha and IkappaBbeta by CR. These findings provide underlying molecular insights into the anti-inflammatory action of CR in relation to the aging process. Based on these and other available data, it is suggested that the "Inflammation Hypothesis of Aging" supports the molecular basis of the inflammatory process as a plausible cause of the aging process.

Increased oxidative stress resulting in the activation of NF-kappaB is thought to play a crucial role in the expression of the cyclooxygenase-2 (COX-2), which is the key enzyme in proinflammatory prostanoid synthesis. In the current study, we investigated whether the aging process affects the status of the redox-sensitive NF-kappaB in rat kidney, and how this age-related modulation is related to COX-2 gene expression and COX-derived reactive oxygen species (ROS). We found that the aging process strongly enhanced the activation of NF-kappaB and its DNA-binding activity with an increased ROS status. Accompanied with the change in the NF-kappaB activity was a decreased IkappaBalpha as confirmed by the increased nuclear p65 protein. Thus, these data strongly indicated that the aging process increases NF-kappaB activity by downregulating IkappaBalpha. A closer examination further revealed that age-related oxidative status correlated with the increased COX-derived prostanoid biosynthetic process is mediated by the increased NF-kappaB-regulated COX activity. This increase in NF-kappaB activity was accompanied by the increased COX-2 mRNA and protein levels. Based on these data, we concluded that the age-related increase in redox-sensitive NF-kappaB translocation and binding activities are associated with increased ROS, and further that this transactivation was modulated by the age-related decrease of IkappaBalpha.

To investigate the role of cyclooxygenase (COX) as a mediator for prostaglandin synthesis in relation to generation of reactive oxidant species (ROS), we quantitated the COX-derived ROS generation and the gene expression of COX-2, an inducible form of COX in aged kidney. In addition, the modulation by dietary restriction was investigated. COX-derived ROS generation increased with age in ad libitum (AL) rats, but dietary restriction (DR) suppressed the level. The amounts of COX-2 protein and mRNA increased with age in AL rats but maintained at low levels in DR group. It was found that the binding characteristics of a nuclear transcription factor, NF-kappaB were altered by aging. The binding activity of NF-kappaB in aged kidney was significantly enhanced with the corresponding increase in mRNA and protein levels. These increases were closely in parallel to the increased ROS generation and gene expression of COX-2. The COX activity shown by NF-kappaB activation and the ROS generation by COX-mediated process were all modulated by DR. Our results suggest that the upregulation of COX-2 during aging may play an important role in many age-related diseases associated with aging process. And this upregulation was attenuated by DR. We propose that the modulation of the redox-sensitive transcription factor may well be a part of the mechanisms underpinning the anti-oxidative action of DR.

Telomerase is an RNA-dependent DNA polymerase that maintains the tandem arrays of telomeric repeats at the eukaryotic chromosome ends. Because of its ability to replenish lost telomeric sequences, telomerase is thought to be required for cell proliferation. At present, very little information on the role of telomerase in aging is available. In the present study, we tested the telomerase activity of Fischer 344 rat testis and liver at 6, 12, 18 and 24 months of age. As the testis is an androgen-dependent tissue, we also investigated the changes of testosterone and mRNA levels of androgen receptor in this tissue. Our results show that the telomerase activity of Fischer 344 rat testis significantly reduced at 24 months of age compared to 6 months of age, and that the mRNA level of telomerase protein component 1 (TLP-1) show a corresponding decrease with the telomerase activity. Interestingly, this down-regulation was not observed in the liver. The testosterone level in testis increased until 18 months of age, but reduced by 50% at 24 months of age. Our conclusions are that the telomerase activity is age-dependent and its change is a tissue-specific phenomenon.

Xanthine oxidoreductase (XD: xanthine dehydrogenase + xanthine oxidase) is a complex enzyme that catalyzes oxidation of hypoxathine to xanthine, subsequently producing uric acid. The enzyme complex exists in separate but interconvertible forms, xanthine dehydrogenase (XDH) and xanthine oxidase (XOD). XOD is one of the major cellular sources of superoxide production and is well known as a causative factor in ischemia/reperfusion damage. At present, almost no information on the conversion status is available with respect to aging. In the present study, we investigated the effect of age on the XOD/XDH status and gene expression in the kidney. In addition, we assessed XOD-induced reactive oxygen species (ROS) using the dichlorofluoroscein (DCF) method. Our results show that XD activity gradually up to 18 months of age and then a slight decrease at 24 months of age. XDH activity showed increases up to 18 months of age, then decreased at 24 months of age. The conversion of XDH to XOD, assessed by changes in the ratios of XOD/(XOD+XDH), showed an age-related increase, which peaked at 24 months. Levels of XD protein and its mRNA paralleled to overall XD activity. ROS generation has tendency to increase with age. Our results suggest that the increased conversion of XDH to XOD observed with age may be an important contributing factor to the increased renal oxidative stress during aging.