Current Aging Science - Volume 7, Issue 3, 2014

The dopaminergic neurons of the substantia nigra (SN), which constitute the origin of the nigrostriatal system, are vulnerable to age-related degenerative processes. For example, in humans there is a relatively small age-related loss of neurons but a marked decline of the dopaminergic phenotype associated with impaired voluntary motor control. However, the mechanisms responsible for the dysfunction and degeneration of SN dopamine neurons remain poorly understood. One potential contributor is mitochondrial dysfunction, resulting from an increased abundance of mitochondrial DNA (mtDNA) mutations such as deletions. Human studies have identified relatively high levels of mtDNA deletions in these cells in both aging and Parkinson’s disease (>35%), with a higher abundance of deletions (>60%) in individual neurons with mitochondrial dysfunction. However, it is unknown whether similar mtDNA mutations occur in other species such as the rat. In the present study, we quantified mtDNA deletion abundance in laser microdissected SN dopaminergic neurons from young and old F344 rats. Our results indicate that mtDNA deletions accumulated with age, with approximately 20% more mtDNA deletions in SN dopaminergic neurons from old compared to young animals. Thus, while rat SN dopaminergic neurons do accumulate mtDNA deletions with aging, this does not reflect the deletion burden in humans, and other mechanisms may be operating to compensate for age-related mtDNA damage in the rat SN dopaminergic neurons.

Telomeres are gene sequences present at chromosomal ends and are responsible for maintaining genome integrity. Telomere length is maximum at birth and decreases progressively with advancing age and thus is considered as a biomarker of chronological aging. This age associated decrease in the length of telomere is linked to various ageing associated diseases like diabetes, hypertension, Alzheimer’s disease, cancer etc. and their associated complications. Telomere length is a result of combined effect of oxidative stress, inflammation and repeated cell replication on it, and thus forming an association between telomere length and chronological aging and related diseases. Thus, decrease in telomere length was found to be important in determining both, the variations in longevity and age-related diseases in an individual. Ongoing and progressive research in the field of telomere length dynamics has proved that aging and age-related diseases apart from having a synergistic effect on telomere length were also found to effect telomere length independently also. Here a short description about telomere length variations and its association with human aging and age-related diseases is reviewed.

Cellular damage and deregulated apoptotic cell death lead to functional impairment, and a main consequence of these events is aging. Cellular damage is initiated by different stress/risk factors such as oxidative stress, inflammation, and heavy metals. These stress/risk factors affect the cellular homeostasis by altering methylation status of several aging and Alzheimer’s disease associated genes; these effects can be manifested immediately after exposure to stress and at later stages of life. However, when cellular damage exceeds certain threshold levels apoptosis is initiated. This review discusses the stress factors involved in cellular damage and the role and potential of TSPO-mediated cell death in aging as well as in Alzheimer’s disease, which is also characterized by extensive cell death. Mitochondrial-mediated apoptotic death through the release of cytochrome c is regulated by TSPO, and increased expression of this protein is observed in both elderly people and in patients with Alzheimer’s disease. TSPO forms and mediates opening of the mitochondrial membrane pore, mPTP and oxidizes cardiolipin, and these events lead to the leakage of apoptotic death mediators, such as cytochrome c, resulting in cell death. However, TSPO has many proposed functions and can also increase steroid synthesis, which leads to inhibition of inflammation and inhibition of the release of apoptotic factors, thereby decreasing cell damage and promoting cell survival. Thus, TSPO mediates apoptosis and decreases the cell damage, which in turn dictates the process of aging as well as the functionality of organs such as the brain. TSPO modulation with ligands in the Alzheimer’s disease mouse model showed improvement in behavioral symptoms, and studies in Drosophila species showed increased cell survival and prolonged lifespan in flies after TSPO inhibition. These data suggest that since effects/signs of stress can manifest at any time, prevention through change in lifestyle and TSPO modulation could be potential strategies for altering both the aging process and the progression of Alzheimer’s disease.

Social insects are an excellent model system for a deeper understanding of the mechanisms of longevity determination because they have a caste system in which the same genome, due to the differential gene expression, can produce both a short-lived worker and a long-lived queen. For example, in the honeybee, Apis mellifera, queens develop from fertilized eggs that are genetically not different from the eggs that develop into workers. They have, however, a much larger size and specialized anatomy, develop substantially faster and live much longer than worker bees. In many social insects including bees, ants, wasps, and termites, queens and workers show up to a 100-fold difference in lifespan, with reproductive queens having longer longevity than non-reproductive workers. Caste differentiation in social insect species is known to be dependent on the larval nutritional environment. In the honeybee, the caste switching is determined by distinguished feeding of larvae. There is accumulating evidence that queen phenotype is driven by epigenetic mechanisms of gene regulation. Dietary differences during the larval development have been found to lead to differential DNA methylation. This results in caste-biased patterns of gene expression, which, in turn, leads to caste-biased phenotypes, such as short-lived workers and long-lived queens. The investigation of physiological, biochemical and molecular aspects of the biology of queens and workers seems to be a promising way to identifying pathways that control longevity and to developing the treatments designed to influence these pathways.

During the 20th century, the average lifespan in the industrialized societies has enormously increased and it is still rising. With the increase in the number of old people, a parallel increase in the number of the disabled elderly is postulated. Thus, the whole society might suffer from an imbalance between the productive segment of the society and a huge segment of helpless people. Moderation of the physiological processes, which enhance disability in aging, turns out to be a major concern in health research and clinical practice. Preservation of brain integrity, which is partly influenced by nutrition, presumably is the main target in the attempt to delay the development of disability of aging. Optimal micronutrient status would moderate the deterioration in brain integrity. The human brain is probably the most vulnerable tissue affected by a long-term unbalanced nutrition and is particularly vulnerable to reactive oxygen species and to oxidative stress, because of its high oxygen requirement, its iron storage capacity and its elevated polyunsaturated fatty acid content, and because of its low synthesis capacity of endogenous antioxidants. The capability of central nervous system (CNS) cells to regenerate is most limited, because their repair is inhibited by anti-apoptotic molecules. Efficient autophagy is the major mechanism that moderates accumulation of aggregating compounds. Autophagy is probably a crucial and a major process in the preservation of brain integrity. Micronutrients (vitamins, trace-elements and also antioxidants) most likely affect brain integrity by normalizing efficient autophagy. Brain sensitivity to metabolic disorders is demonstrated by the effect of homocysteine on metabolic pathways, on brain integrity and on the cognitive capacity. Brain imaging might be used as a surrogate for detecting long-lasting low status of micronutrients. Comprehensive evaluation of brain scans concomitantly with blood micronutrient examinations may provide reliable criteria for the estimation of the optimal micronutrient intakes or blood concentrations. Recommended dietary intakes for micronutrients are based on a list of biomarkers, but have not been suggested a safe range for their intake or blood concentration. According to many studies, a U-shaped curve prevails for the effect of serum calcidiol concentration on the relative risk of morbidity and mortality. An increased relative risk of morbidity and mortality with lower serum calcidiol has been shown in almost all the studies. A safe range of 20-40 ng/mL was identified for serum calcidiol. A significant detrimental effect of serum calcidiol on the hazard ratio for the combined data of all-cause mortality and acute coronary syndrome morbidity was shown at a concentration higher than 36 ng/ml. Most of the tolerable upper intake levels for the micronutrients, published by authorized institutions, were set without considering the long-term effects of overdosing. Excessive intake of almost all the micromutrients, particularly for a long period of time, produces adverse effects. In most of the elderly people prevail an insufficient intake of one or more micronutruients. Therefore, until an efficient laboratory system for evaluating blood levels is established, a moderate 'multivitamin' supplementation at an amount of about half the American RDA for most of the micronutrients is suggested.

Although some evidence is consistent with the notion that distinct cortical systems support memory and perception, mounting evidence supports a representational-hierarchical view of cognition, which posits that distinctions lie in simple feature representations versus more complex conjunctive representations of many stimulus features simultaneously. Thus, typical memory tasks engage different regions from typical perception tasks because they inherently test information on opposing ends of this continuum. Memory deficits are reliably reported with age, but the tasks used to make these conclusions predominantly rely on conjunctive representations. To test the extent to which age-related deficits may be accounted for by perceptual processing, this study investigated discriminations involving conjunctive representations in older adults. Results show that adults aged 50 to 77 are impaired, relative to their younger counterparts, on discriminations requiring feature conjunctions, but not simple feature representations. These findings support recent data showing an agerelated decline in the ability to form conjunctive representations. Furthermore, these data suggest that some ‘mnemonic’ deficits associated with age may in fact be the result of deficits in perception rather than memory.

This study determines the effects of growing and aging on lung physiological volumes and capacities and the incidence of inflammation in the small airways with age in rats. A reference database comprising of body weight gain, lung physiological volumes and capacities and an anatomopathological study of lung lesions over 240 Wistar rats from two to 24 -mo, is described. Tidal volume (TV), minute respiratory volume (MRV), and forced vital capacity (FVC) decreased during the first six months of life and then remain constant until 24 -mo of age. The respiratory frequency (Rf) and dynamical compliance (Cdyn) maintain at constant values from 2 to 24- mo of age; the functional residual capacity (FRC) increases in the first 6 -mo and then remains constant up to 24 -mo. It was verified a less intensive inflammation in the small airways with age, when compared with the median and large airways. In conclusion: This study showed the normal parameters for lung volumes and capacities and the incidence of infections for growing and aging male and female rats. The age-related data on these main respiratory parameters in rats would be useful in studies of aging-related disorders using this model and for safety pharmacology studies necessary for the development of drugs.

Objectives: Materials and Methods: Randomized double blind longitudinal study was performed from December 1, 2012 to June 15, 2013 in urological ward of gerontological hospital (Vladivostok city, Russian Federation). 378 men and women over 65 (average age: 69.8 (7.2)), who suffered from stage 1 (initial) hypertension, had participated in this study. During the treatment all patients, except for those who were assigned to the control group, received Loop Diuretic Furosemide dosed at 20-30 mg per day and Solifenacin dosed at 5 mg per day (First comparison group) and 10 mg per day (Second comparison group). Functional performance of lower urinary tract (LUT) at enrollment and at the end of the treatment was evaluated using ICIQ-SF questionnaires. During the whole period of treatment patients were keeping bladder diaries where records on frequency and volume of daily urinations, episodes of urgency (EU), episodes of incontinence (EI) and other symptoms were kept. Result: Comparison of data obtained from control group (7.2%), group of the patients treated with Furosemide and standard- dosed (11.1%) and low-dosed (16.2%) Solifenacin allows to draw conclusion on the absence of significant differences in number of patients with symptoms of OAB between these groups (p ≥ 0.05). At the same time percentage of patients with symptoms of OAB in the group treated only with Furosemide was significantly different from three other groups (p ≤ 0.05) and reached 46.1%. Conclusion: Risk of developing symptoms of OAB in elderly patients, whose hypertensive disease has been treated with loop diuretic for a long period of time, decreases significantly, provided antimuscarinic drug Solifencin is administered at the same time. Administration of low dosed Solifenacin is sufficient for significant decrease in risk of developing symptoms of overactive bladder.