Dietary modulation of prostanoid synthesis in the aging process: role of cyclooxygenase-2

Lipids as Regulators of Cellular Senescence

Lipids are key macromolecules that perform a multitude of biological functions ranging from maintaining structural integrity of membranes, energy storage, to signaling molecules. Unsurprisingly, variations in lipid composition and its levels can influence the functional and physiological state of the cell and its milieu. Cellular senescence is a permanent state of cell cycle arrest and is a hallmark of the aging process, as well as several age-related pathologies. Senescent cells are often characterized by alterations in morphology, metabolism, chromatin remodeling and exhibit a complex pro-inflammatory secretome (SASP). Recent studies have shown that the regulation of specific lipid species play a critical role in senescence. Indeed, some lipid species even contribute to the low-grade inflammation associated with SASP. Many protein regulators of senescence have been well characterized and are associated with lipid metabolism. However, the link between critical regulators of cellular senescence and senescence-associated lipid changes is yet to be elucidated. Here we systematically review the current knowledge on lipid metabolism and dynamics of cellular lipid content during senescence. We focus on the roles of major players of senescence in regulating lipid metabolism. Finally, we explore the future prospects of lipid research in senescence and its potential to be targeted as senotherapeutics.

Stabilization of telomere by the antioxidant property of polyphenols: Anti-aging potential

Aging is a form of a gradual loss of physiological integrity that results in impaired cellular function and ultimately increased vulnerability to disease and death. This process is a significant risk factor for critical age-related disorders such as cancer, diabetes, cardiovascular disease, and neurological conditions. Several mechanisms contribute to aging, most notably progressive telomeres shortening, which can be counteracted by telomerase enzyme activity and increasing in this enzyme activity associated with partly delaying the onset of aging. Individual behaviors and environmental factors such as nutrition affect the life-span by impact the telomerase activity rate. Healthy eating habits, including antioxidant intakes, such as polyphenols, can have a positive effect on telomere length by this mechanism. In this review, after studying the underlying mechanisms of aging and understanding the relationships between telomeres, telomerase, and aging, it has been attempted to explain the effect of polyphenols on reversing the oxidative stress and aging process.

Inonotus obliquus Extracts Decreased Expression of MMP1 mRNA via JNK-AP-1 Axis

Inonotus obliquus, which is parasitic on birch and other trees, is a fungus in the family Hymenochaetaceae. In this study, we investigated whether Inonotus obliquus extracts used in traditional medicine were decreased in the expression of matrix metalloproteinases-1 (MMP-1) in the normal human dermal fibroblasts. As shown in our results, extracts of Inonotus obliquus decreased MMP1 expression in oxidative stress-exposed normal human dermal fibroblasts. Additionally, Inonotus obliquus extracts decreased AP-1 transcriptional activity and phospho-JNK in oxidative stress-exposed normal human dermal fibroblasts. Oxidative stress mediated the elevation of MMP1 mRNA expression and was well regulated by the JNK-AP-1 axis. Therefore, the results suggest that Inonotus obliquus extracts decreased MMP1 mRNA expression by regulating JNK-AP-1 axis. Additionally, Inonotus obliquus extracts have the potential to reduce collagen destruction and the formation of wrinkles and to be used as a cosmetic ingredient.

Redefining Chronic Inflammation in Aging and Age-Related Diseases: Proposal of the Senoinflammation Concept

Age-associated chronic inflammation is characterized by unresolved and uncontrolled inflammation with multivariable low-grade, chronic and systemic responses that exacerbate the aging process and age-related chronic diseases. Currently, there are two major hypotheses related to the involvement of chronic inflammation in the aging process: molecular inflammation of aging and inflammaging. However, neither of these hypotheses satisfactorily addresses age-related chronic inflammation, considering the recent advances that have been made in inflammation research. A more comprehensive view of age-related inflammation, that has a scope beyond the conventional view, is therefore required. In this review, we discuss newly emerging data on multi-phase inflammatory networks and proinflammatory pathways as they relate to aging. We describe the age-related upregulation of nuclear factor (NF)-κB signaling, cytokines/chemokines, endoplasmic reticulum (ER) stress, inflammasome, and lipid accumulation. The later sections of this review present our expanded view of age-related senescent inflammation, a process we term "senoinflammation", that we propose here as a novel concept. As described in the discussion, senoinflammation provides a schema highlighting the important and ever-increasing roles of proinflammatory senescence-associated secretome, inflammasome, ER stress, TLRs, and microRNAs, which support the senoinflammation concept. It is hoped that this new concept of senoinflammation opens wider and deeper avenues for basic inflammation research and provides new insights into the anti-inflammatory therapeutic strategies targeting the multiple proinflammatory pathways and mediators and mediators that underlie the pathophysiological aging process.

RNA-Seq analysis reveals new evidence for inflammation-related changes in aged kidney

Age-related dysregulated inflammation plays an essential role as a major risk factor underlying the pathophysiological aging process. To better understand how inflammatory processes are related to aging at the molecular level, we sequenced the transcriptome of young and aged rat kidney using RNA-Seq to detect known genes, novel genes, and alternative splicing events that are differentially expressed. By comparing young (6 months of age) and old (25 months of age) rats, we detected 722 up-regulated genes and 111 down-regulated genes. In the aged rats, we found 32 novel genes and 107 alternatively spliced genes. Notably, 6.6% of the up-regulated genes were related to inflammation (P < 2.2 × 10-16, Fisher exact t-test); 15.6% were novel genes with functional protein domains (P = 1.4 × 10-5); and 6.5% were genes showing alternative splicing events (P = 3.3 × 10-4). Based on the results of pathway analysis, we detected the involvement of inflammation-related pathways such as cytokines (P = 4.4 × 10-16), which were found up-regulated in the aged rats. Furthermore, an up-regulated inflammatory gene analysis identified the involvement of transcription factors, such as STAT4, EGR1, and FOSL1, which regulate cancer as well as inflammation in aging processes. Thus, RNA changes in these pathways support their involvement in the pro-inflammatory status during aging. We propose that whole RNA-Seq is a useful tool to identify novel genes and alternative splicing events by documenting broadly implicated inflammation-related genes involved in aging processes.

Hypertension and aging

Hypertension is a highly prevalent condition with numerous health risks, and the incidence of hypertension is greatest among older adults. Traditional discussions of hypertension have largely focused on the risks for cardiovascular disease and associated events. However, there are a number of collateral effects, including risks for dementia, physical disability, and falls/fractures which are increasingly garnering attention in the hypertension literature. Several key mechanisms--including inflammation, oxidative stress, and endothelial dysfunction--are common to biologic aging and hypertension development and appear to have key mechanistic roles in the development of the cardiovascular and collateral risks of late-life hypertension. The objective of the present review is to highlight the multi-dimensional risks of hypertension among older adults and discuss potential strategies for treatment and future areas of research for improving overall care for older adults with hypertension.

miR-335 correlates with senescence/aging in human mesenchymal stem cells and inhibits their therapeutic actions through inhibition of AP-1 activity

MicroRNAs, small noncoding RNAs, regulate gene expression primarily at the posttranscriptional level. We previously found that miR-335 is critically involved in the regulation and differentiation capacity of human mesenchymal stem cells (hMSCs) in vitro. In this study, we investigated the significance of miR-335 for the therapeutic potential of hMSCs. Analysis of hMSCs in ex vivo culture demonstrated a significant and progressive increase in miR-335 that is prevented by telomerase. Expression levels of miR-335 were also positively correlated with donor age of hMSCs, and were increased by stimuli that induce cell senescence, such as γ-irradiation and standard O2 concentration. Forced expression of miR-335 resulted in early senescence-like alterations in hMSCs, including: increased SA-β-gal activity and cell size, reduced cell proliferation capacity, augmented levels of p16 protein, and the development of a senescence-associated secretory phenotype. Furthermore, overexpression of miR-335 abolished the in vivo chondro-osseous potential of hMSCs, and disabled their immunomodulatory capacity in a murine experimental model of lethal endotoxemia. These effects were accompanied by a severely reduced capacity for cell migration in response to proinflammatory signals and a marked reduction in Protein Kinase D1 phosphorylation, resulting in a pronounced decrease of AP-1 activity. Our results demonstrate that miR-335 plays a key role in the regulation of reparative activities of hMSCs and suggests that it might be considered a marker for the therapeutic potency of these cells in clinical applications.

Mechanisms involved in developmental programming of hypertension and renal diseases. Gender differences

BACKGROUND

A substantial body of epidemiological and experimental evidence suggests that a poor fetal and neonatal environment may "program" susceptibility in the offspring to later development of cardiovascular, renal and metabolic diseases.

MATERIALS AND METHODS

This review focuses on current knowledge from the available literature regarding the mechanisms linking an adverse developmental environment with an increased risk for cardiovascular, renal and metabolic diseases in adult life. Moreover, this review highlights important sex-dependent differences in the adaptation to developmental insults.

RESULTS

Developmental programming of several diseases is secondary to changes in different mechanisms inducing important alterations in the normal development of several organs that lead to significant changes in birth weight. The different diseases occurring as a consequence of an adverse environment during development are secondary to morphological and functional cardiovascular and renal changes, to epigenetic changes and to an activation of several hormonal and regulatory systems, such as angiotensin II, sympathetic activity, nitric oxide, COX2-derived metabolites, oxidative stress and inflammation. The important sex-dependent differences in the developmental programming of diseases seem to be partly secondary to the effects of sex hormones. Recent studies have shown that the progression of these diseases is accelerated during aging in both sexes.

CONCLUSIONS

The cardiovascular, renal and metabolic diseases during adult life that occur as a consequence of several insults during fetal and postnatal periods are secondary to multiple structural and functional changes. Future studies are needed in order to prevent the origin and reduce the incidence and consequences of developmental programmed diseases.

Down-regulation of oxidative stress and COX-2 and iNOS expressions by dimethyl lithospermate in aged rat kidney

Oxidative stress has been proposed to be a major cause of aging and many age-related diseases. Peroxynitrite (ONOO(-)), formed from the reaction of superoxide ((•)O2 (-)) and nitric oxide (NO), is a cytotoxic species that can oxidize various cellular components, such as proteins, lipids, and DNA. The present study investigated whether dimethyl lithospermate (DML), isolated from Salvia miltiorrhiza, modulates age-related increases of ONOO(-), NO, and reactive species (RS) levels and expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). For this study, 20-month-old rats were intraperitoneally injected with 5 or 10 mg/kg/day of DML, and 6-month-old rats were used as young control animals. Our results indicated that DML reduces ONOO(-) levels in a dose-dependent manner. The data also revealed that DML has significant inhibitory effects on NO metabolites and RS generation in a dose-dependent manner during aging. Furthermore, the results of Western blot analysis revealed that DML treatment reduces age-associated increases in COX-2 and iNOS expressions. Thus, this study found that DML caused the decrease of renal oxidative stress and COX-2 and iNOS expressions in aged rats. The significance of the present study is the finding of DML in its potential application against the aging process.

The effect of lipopolysaccharide on enhanced inflammatory process with age: Modulation of NF-κB

Oxidative stress is thought to be a causative factor for age-related damage in a wide variety of cellular constituents that can lead to dysfunction and various pathological conditions, including the inflammatory process. At the molecular level, the redox-sensitive transcription factor, NF-κB plays a key role in the regulation of the inflammatory process, along with cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). We studied the mechanism underlying the modulation of the inflammatory reaction with age by investigating NF-κB activation and the expression of COX-2, iNOS, and cytokines genes in hepatic tissues isolated from young and old rats. We expanded our investigation of these factors in rats injected with the inflammatory activator, lipopolysaccharide (LPS). Data showed that NF-κB activity was up-regulated with age and was further enhanced by LPS injection, indicating an increased susceptibility and sensitivity to the inflammatory stimulus with age. To explore further the molecular events leading to NF-κB activation, we investigated the inhibitory component of NF-κB complex, IκB. Cytosolic IκBα, but not IκBβ, was significantly decreased in both old and LPS-treated rats, signifying the enhanced migration of cytosolic NF-κB complex into the nucleus following dissociation from the inhibitor. The appearance of the polypeptide, p65, as determined in the nucleus, corresponded with the change in IκBα, providing further supporting evidence for the molecular process involved in NF-κB activation. Our additional investigation of two proinflammatory-related enzymes, COX-2 and iNOS, and three cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α, clearly showed aged-related increases, in corroboration with the NF-κB activation. Our results demonstrated that LPS injection caused the enhanced gene expression of inducible proinflammatory proteins, COX-2 and iNOS through NF-κB activation.

Renal effects of prolonged high protein intake and COX2 inhibition on hypertensive rats with altered renal development

Cyclooxygenase 2 (COX2) is involved in regulating renal hemodynamics after renal ablation. It is also known that high protein intake (HPI) leads to a deterioration of renal function when there is preexisting renal disease and that there are important gender differences in the regulation of renal function. This study tested the hypothesis that the role of COX2 in regulating renal function and the renal hemodynamic effects elicited by HPI are enhanced when nephrogenesis is altered during renal development. It was also expected that the role of COX2 and the effects elicited by HPI are age and sex dependent. Newborn Sprague-Dawley rats were treated with an AT1 ANG II receptor antagonist during the nephrogenic period (ARAnp). Experiments were performed at 3–4 and 10–11 mo of age. Arterial pressure was elevated ( P < 0.05) at both ages and in both sexes of ARAnp-treated rats. Renal COX2 expression was only elevated ( P < 0.05) at 10–11 mo of age in both sexes of ARAnp-treated rats. COX2 inhibition induced greater renal vasoconstriction in male and female hypertensive than in normotensive rats at both ages. HPI did not induce glomerular filtration rate (GFR) in the youngest hypertensive rats and in the oldest female hypertensive rats. However, the GFR decreased during HPI (0.63 ± 0.07 to 0.19 ± 0.05 ml/min) in the oldest male hypertensive rats. The HPI-induced increment in proteinuria was greater ( P < 0.05) in male (99 ± 22 mg/day) than in female (30 ± 8 mg/day) hypertensive rats. These results show that COX2 plays an important role in the regulation of renal function when renal development is altered and that prolonged HPI can lead to a renal insufficiency in males but not in females with reduced nephron endowment.

Molecular inflammation as an underlying mechanism of the aging process and age-related diseases

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.

Anti-aging effects of cyanidin under a stress-induced premature senescence cellular system

The anti-aging effects of cyanidin were investigated under stress-induced premature senescence (SIPS) using WI-38 human diploid fibroblasts. WI-38 cells that were treated with 300 microM H(2)O(2) showed losses of cell viability, increased lipid peroxidation, and shortened cell lifespans. However, treatment with cyanidin attenuated cellular oxidative stress through increase of cell viability and the inhibition of lipid peroxidation. In addition, the life spans of young-, middle-, and old-aged WI-38 cells were prolonged by cyanidin treatment. Furthermore, H(2)O(2)-treated WI-38 cells significantly increased mRNA and protein expressions of nuclear factor-kappaB, cyclooxygenase-2, and inducible nitric oxide synthase, while those treated with cyanidin had significantly decreased expressions. These results suggest that cyanidin may delay the aging process by attenuating oxidative stress under the SIPS cellular model.

Molecular inflammation: underpinnings of aging and age-related diseases

Recent scientific studies have advanced the notion of chronic inflammation as a major risk factor underlying aging and age-related diseases. In this review, low-grade, unresolved, molecular inflammation is described as an underlying mechanism of aging and age-related diseases, which may serve as a bridge between normal aging and age-related pathological processes. Accumulated data strongly suggest that continuous (chronic) upregulation of pro-inflammatory mediators (e.g., TNF-alpha, IL-1beta, IL-6, COX-2, iNOS) are induced during the aging process due to an age-related redox imbalance that activates many pro-inflammatory signaling pathways, including the NF-kappaB signaling pathway. These pro-inflammatory molecular events are discussed in relation to their role as basic mechanisms underlying aging and age-related diseases. Further, the anti-inflammatory actions of aging-retarding caloric restriction and exercise are reviewed. Thus, the purpose of this review is to describe the molecular roles of age-related physiological functional declines and the accompanying chronic diseases associated with aging. This new view on the role of molecular inflammation as a mechanism of aging and age-related pathogenesis can provide insights into potential interventions that may affect the aging process and reduce age-related diseases, thereby promoting healthy longevity.

Betaine modulates age-related NF-kappaB by thiol-enhancing action

Depletion of glutathione levels and perturbations in redox status are considered to play a crucial role in aging and chronic inflammatory processes through the activation of redox sensitive transcription factors, including nuclear factor-kappaB (NF-kappaB). In the current study, we assessed the regulatory action of dietary betaine in the suppression of NF-kappaB by comparing kidney tissue from old, betaine-supplemented rats or non-betaine-supplemented rats (age 21 months) and 7 month-old rats. In addition, cultured HEK 293T cells were utilized for the molecular assessment of betaine's restorative ability of redox status when treating cells with potent glutathione (GSH)-depleting agents. Results showed that in old rats a short-term feeding (10 d) with betaine attenuated the age-related decrease in thiol levels, increase in reactive species and TNFalpha expression via NF-kappaB activation, compared to the young controls. These findings were verified in the cell-cultured system. Further investigations found that redox imbalance due to thiol depletion caused increased NF-kappaB activation, and cyclooxygenase (COX)-2 and TNFalpha levels, both of which were suppressed by betaine treatment. Based on both in vivo and in vitro data, we concluded that betaine exerts its efficacy by maintaining thiol status in the regulation of COX-2 and TNFalpha via NF-kappaB activation during aging.

Age-related changes in monocyte and platelet cyclooxygenase expression in healthy male humans and rats

Cyclooxygenase (COX) catalyses the formation of prostanoids that are crucial in maintaining hemostasis and important in inflammation. Animal studies reveal that COX-1 and COX-2 expression increase in some cell types during aging. This study determined age-related changes in COX expression in platelets and monocytes. Platelets and mononuclear cells were isolated from healthy male human volunteers from 18 to 28 and from 55 to 65 years of age, as well as male rats 8 and 54 weeks old for comparison. Western blot analysis was performed using selective antibodies against COX-1 and COX-2, followed by densitometrical analysis. In humans, an age-related increase in COX-2 expression in mononuclear cells was observed, with a 70% increase in the older age group. In rat studies, a 50% increase of COX-2 protein occurred in mononuclear cells of 54-week-old rats, compared with 8-week-old rats. For COX-1, an age-related increase of 50% occurred in rat platelets, but no difference occurred in the platelets' COX-1 levels between young and elderly human age groups. The increased COX-2 in monocytes of older humans, which is mirrored in rats, may have downstream implications in atherosclerosis and cardiovascular risk as mononuclear prostanoids are implicated in atherosclerotic plaque stability.

The effect of age and calorie restriction on HIF-1-responsive genes in aged liver

Hypoxia inducible factor-1 (HIF-1) regulates transactivation of several genes in response to hypoxia condition. We explore hepatic HIF-1 responsive gene regulation during aging and the age-related changes of the HIF-1 related gene activation in young and old rats. Results indicate that the aging process induces the activation of HIF-1alpha, which is accompanied by increased HIF-1 DNA binding. This increased binding activity is accompanied by the increase of HIF-1-dependent genes, heme oxygenase-1 (HO-1), vascular endothelial growth factor (VEGF), erythropoietin (EPO), and inducible nitric oxide synthase (iNOS), which all showed remarkable up-regulation during aging process. In contrast, the increased HIF-1 related gene expression was effectively blunted by the anti-oxidative action of calorie restriction in aged rat liver. We propose that age-related HIF-1 binding activity may well be influenced by the increased pro-oxidative conditions of aged animals, which up-regulate HIF-1-dependent gene expression.

The molecular inflammatory process in aging

Emerging pathological evidence indicates that major chronic aging-related diseases such as atherosclerosis, arthritis, dementia, osteoporosis, and cardiovascular diseases, are inflammation-related. In this review, inflammation is examined as a possible underlying basis for the molecular alterations that link aging and age-related pathological processes. A proposal for the molecular inflammation hypothesis of the aging views the redox derangement that occurs during aging as the major factor for increased risk for age-related inflammation. Accumulated data strongly indicate the activation of redox-sensitive transcription factors and dysregulated gene expression under the age-related oxidative stress seems to be the major culprits. Key players involved in the inflammatory process are the age-related upregulation of NF-kappaB, IL-1beta, IL-6, TNFalpha, cyclooxygenase-2, adhesion molecules, and inducible NO synthase. Furthermore, data are presented on the molecular events involved in age-related NF-kappaB activation and phosphorylation by IkappaB kinase/NIK and MAPKs. Experimental data on anti-aging calorie restriction (CR) for its antiinflammatory efficacy by suppressing the upregulated proinflammatory mediators will be reviewed. Also, the involvement of another super family of transcription factors, PPARs (PPARalpha, gamma) as regulators of proinflammatory responses and NF-kappaB signaling pathway is described as well as a discussion on the physiological significance of a well-maintained balance between NF-kappaB and PPARs.

Involvement of Rel/NF-kappa B transcription factors in senescence

Senescence is now established as a genetically controlled phenomenon that alters different cell functions, including proliferation, apoptosis, resistance to stress, and energetic metabolism. Underlying changes in gene expression are governed by some transcription factors, whose expression or activity must change with senescence as well. Transcription factors of the Rel/NF-kappa B family are good candidates to participate in the establishment of senescence. Arguments range from correlation between cell functions controlled by these factors and cell functions altered during senescence, to phenotypes resulting from in vitro manipulations of Rel/NF-kappa B activity.

Molecular inflammation hypothesis of aging based on the anti-aging mechanism of calorie restriction

Accumulating evidence strongly suggests that oxidative stress underlies aging processes. Research provides consistent evidence that calorie restriction (CR) reduces age-related oxidative stress and has anti-inflammatory properties. However, information is lacking on the molecular mechanism that would better define the interrelation of reactive oxygen species and nitrogen species and the pro-inflammatory states of the aging process. In this review, the biochemical and molecular bases of the inflammatory process in the aging process are analyzed to delineate the molecular inflammation hypothesis of aging. The key players involved in the proposed hypothesis are the age-related upregulation of NF-kappa B, IL-1 beta, IL-6, TNFalpha, cyclooxygenase-2, and inducible NO synthase, all of which are attenuated by CR. Furthermore, age-related NF kappa B activation is associated with phosphorylation by I kappa B kinase/NIK and MAPKs, while CR blocked these activation processes. The modulation of these factors provides molecular insights of the anti-inflammatory action of CR in relation to the aging process. Based on available finding and our recent supporting evidence, we prefer to use "molecular inflammation" to emphasize the importance of the molecular reaction mechanisms and their aberrance, predisposing to fully expressed chronic inflammatory phenomena. It was further proposed that CR's major force of the regulation of redox-sensitive inflammation may well be its life-prolonging action.

Oxidative stress and vascular aging

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.

Topography of neurochemical alterations in the CNS of aged rats

We have performed a general survey study on alterations of neurotransmitter-related and glia-related neurochemical markers in various regions of the CNS of aged (30-month-old) as compared to adult (4-month-old) rats. We have found significant decreases in the level of neurochemical parameters related to the cholinergic and GABAergic systems in several regions of the CNS of aged rats. Only few of the alterations present at the age of 30 months, were present in a group of rat of intermediate age (20 months) included in the present study. Less widespread alterations were found concerning the glutamatergic neurotransmission system. Neurochemical markers related to glial cells (astrocytes and oligodendrocytes) showed a remarkable stability in aged rats as compared to neurotransmitter-related markers. Considering the various CNS areas examined in the present study, the spinal cord of the aged rats was the region showing the most profound alterations of neurochemical parameters, as compared to the various brain areas of the same rats. The present results suggest that moderate and region-specific alterations of neurotransmitter-related parameters occur during normal aging and that glia-related markers are fundamentally stable in the absence of specific pathologies.