A Scientific Approach to Anti-Ageing Therapies: State of the Art

Geniposide effectively reverses cognitive impairment and inhibits pathological cerebral damage by regulating the mTOR Signal pathway in APP∕PS1 mice

OBJECTIVE

The aim of this study is to investigate the protective effects as well as the underlying molecular mechanisms of geniposide in APP/PS1 transgenic mice.

METHOD

APP/PS1 mice were subjected to intragastric administration of geniposide (50 mg/kg/d) for 8 weeks (including a 2-week behavior test). The novel object recognition (NOR) and the Morris water maze (MWM) tests were used for behavioral assessments. Aβ1-40 plaques in mice cortices and hippocampi are visualized with immunohistochemistical staining. ELISA was used to quantify the levels of soluble Aβ1-40 and Aβ1-42 in the hippocampus. Western blot was used to detect p-Akt/Akt, p-mTOR/mTOR and p-4E-BP1/4E-BP1 levels. The relative mRNA levels of Akt, mTOR and 4E-BP1 were quantified using real-time PCR (RT-PCR).

RESULTS

Geniposide alleviated cognitive impairment by improving the ability of novel object exploration, spatial memory, and reduced the level of Aβ in the brain of APP/PS1 mice. Geniposide possibly regulates mTOR-related proteins through modification of phosphorylation. Geniposide markedly lowered p-mTOR and p-Akt expressions while elevating p-4E-BP1 expression. Geniposide obviously reduced the relative mRNA levels of Akt and mTOR and increased the relative mRNA level of 4E-BP1.

CONCLUSION

Geniposide is able to alleviate cognitive impairments and cerebral damage in APP/PS1 mice, with its neuroprotective effects likely mediated via modulation of the mTOR signaling pathway.

A Review and Hypothesized Model of the Mechanisms That Underpin the Relationship Between Inflammation and Cognition in the Elderly

Age is associated with increased risk for several disorders including dementias, cardiovascular disease, atherosclerosis, obesity, and diabetes. Age is also associated with cognitive decline particularly in cognitive domains associated with memory and processing speed. With increasing life expectancies in many countries, the number of people experiencing age-associated cognitive impairment is increasing and therefore from both economic and social terms the amelioration or slowing of cognitive aging is an important target for future research. However, the biological causes of age associated cognitive decline are not yet, well understood. In the current review, we outline the role of inflammation in cognitive aging and describe the role of several inflammatory processes, including inflamm-aging, vascular inflammation, and neuroinflammation which have both direct effect on brain function and indirect effects on brain function via changes in cardiovascular function.

Thamnolia vermicularis extract improves learning ability in APP/PS1 transgenic mice by ameliorating both Aβ and Tau pathologies

Considering the complicated pathogenesis of Alzheimer's disease (AD), multi-targets have become a focus in the discovery of drugs for treatment of this disease. In the current work, we established a multi-target strategy for discovering active reagents capable of suppressing both Aβ level and Tau hyperphosphorylation from natural products, and found that the ethanol extract of Thamnolia vermicularis (THA) was able to improve learning ability in APP/PS1 transgenic mice by inhibiting both Aβ levels and Tau hyperphosphorylation. SH-SY5Y and CHO-APP/BACE1 cells and primary astrocytes were used in cell-based assays. APP/PS1 transgenic mice [B6C3-Tg(APPswe, PS1dE9)] were administered THA (300 mg·kg-1·d-1, ig) for 100 d. After the administration was completed, the learning ability of the mice was detected using a Morris water maze (MWM) assay; immunofluorescence staining, Congo red staining and Thioflavine S staining were used to detect the senile plaques in the brains of the mice. ELISA was used to evaluate Aβ and sAPPβ contents, and Western blotting and RT-PCR were used to investigate the relevant signaling pathway regulation in response to THA treatment. In SH-SY5Y cells, THΑ (1, 10, 20 μg/mL) significantly stimulated PI3K/AKT/mTOR and AMPK/raptor/mTOR signaling-mediated autophagy in the promotion of Aβ clearance as both a PI3K inhibitor and an AMPK indirect activator, and restrained Aβ production as a suppressor against PERK/eIF2α-mediated BACE1 expression. Additionally, THA functioned as a GSK3β inhibitor with an IC50 of 1.32±0.85 μg/mL, repressing Tau hyperphosphorylation. Similar effects on Aβ accumulation and Tau hyperphosphorylation were observed in APP/PS1 transgenic mice treated with THA. Furthermore, administration of THA effectively improved the learning ability of APP/PS1 transgenic mice, and markedly reduced the number of senile plaques in their hippocampus and cortex. The results highlight the potential of the natural product THA for the treatment of AD.

Small molecule LX2343 ameliorates cognitive deficits in AD model mice by targeting both amyloid β production and clearance

AIM

Streptozotocin (STZ) is widely used to induce oxidative damage and to impair glucose metabolism, apoptosis, and tau/Aβ pathology, eventually leading to cognitive deficits in both in vitro and in vivo models of Alzheimer's disease (AD). In this study, we constructed a cell-based platform using STZ to induce stress conditions mimicking the complicated pathologies of AD in vitro, and evaluated the anti-amyloid effects of a small molecule, N-(1,3-benzodioxol-5-yl)-2-[5-chloro-2-methoxy(phenylsulfonyl)anilino]acetamide (LX2343) in the amelioration of cognitive deficits in AD model mice.

METHODS

Cell-based assays for screening anti-amyloid compounds were established by assessing Aβ accumulation in HEK293-APPsw and CHO-APP cells, and Aβ clearance in primary astrocytes and SH-SY5Y cells after the cells were treated with STZ in the presence of the test compounds. Autophagic flux was observed using confocal laser scanning microscopy. APP/PS1 transgenic mice were administered LX2343 (10 mg·kg-1·d-1, ip) for 100 d. After LX2343 administration, cognitive ability of the mice was evaluated using Morris water maze test, and senile plaques in the brains were detected using Thioflavine S staining. ELISA assay was used to evaluate Aβ and sAPPβ levels, while Western blot analysis was used to measure the signaling proteins in both cell and animal brains.

RESULTS

LX2343 (5-20 μmol/L) dose-dependently decreased Aβ accumulation in HEK293-APPsw and CHO-APP cells, and promoted Aβ clearance in SH-SY5Y cells and primary astrocytes. The anti-amyloid effects of LX2343 were attributed to suppressing JNK-mediated APPThr668 phosphorylation, thus inhibiting APP cleavage on one hand, and inhibiting BACE1 enzymatic activity with an IC50 value of 11.43±0.36 μmol/L, on the other hand. Furthermore, LX2343 acted as a non-ATP competitive PI3K inhibitor to negatively regulate AKT/mTOR signaling, thus promoting autophagy, and increasing Aβ clearance. Administration of LX2343 in APP/PS1 transgenic mice significantly ameliorated cognitive deficits and markedly ameliorated the Aβ pathology in their brains.

CONCLUSION

LX2343 ameliorates cognitive dysfunction in APP/PS1 transgenic mice via both Aβ production inhibition and clearance promotion, which highlights the potential of LX2343 in the treatment of AD.

Arctigenin effectively ameliorates memory impairment in Alzheimer's disease model mice targeting both β-amyloid production and clearance

Alzheimer's disease (AD) chiefly characterizes a progressively neurodegenerative disorder of the brain, and eventually leads to irreversible loss of intellectual abilities. The β-amyloid (Aβ)-induced neurodegeneration is believed to be the main pathological mechanism of AD, and Aβ production inhibition or its clearance promotion is one of the promising therapeutic strategies for anti-AD research. Here, we report that the natural product arctigenin from Arctium lappa (L.) can both inhibit Aβ production by suppressing β-site amyloid precursor protein cleavage enzyme 1 expression and promote Aβ clearance by enhancing autophagy through AKT/mTOR signaling inhibition and AMPK/Raptor pathway activation as investigated in cells and APP/PS1 transgenic AD model mice. Moreover, the results showing that treatment of arctigenin in mice highly decreased Aβ formation and senile plaques and efficiently ameliorated AD mouse memory impairment strongly highlight the potential of arctigenin in anti-AD drug discovery.

Functional foods and nutraceuticals as therapeutic tools for the treatment of diet-related diseases

In Western societies, the incidence of diet-related diseases is progressively increasing due to greater availability of hypercaloric food and a sedentary lifestyle. Obesity, diabetes, atherosclerosis, and neurodegeneration are major diet-related pathologies that share a common pathogenic denominator of low-grade inflammation. Functional foods and nutraceuticals may represent a novel therapeutic approach to prevent or attenuate diet-related disease in view of their ability to exert anti-inflammatory responses. In particular, activation of intestinal T regulatory cells and homeostatic regulation of the gut microbiota have the potential to reduce low-grade inflammation in diet-related diseases. In this review, clinical applications of polyphenol-rich functional foods and nutraceuticals in postprandial inflammation, obesity, and ageing will be discussed. We have placed special emphasis on polyphenols since they are broadly distributed in plants.

Mediterranean diet and longevity in Sicily: survey in a Sicani Mountains population

Over the past several years, increasing evidence suggests that the Mediterranean diet has a beneficial influence on several age-related diseases, showing protective effect on health and longevity. Mediterranean diet refers to dietary patterns found in olive-growing regions of the Mediterranean countries. Previous data reported that in Sicily, Italy, the largest Mediterranean island, there are some mountainous regions where there is a high frequency of male centenarians with respect to the Italian average. The aim of the present study was to characterize centenarians living in one of this region, the Sicani Mountains, located in western Sicily. Present data shows that in this zone there are more centenarians with respect to the Italian average. In fact, in the three villages of the Sicani Mountains, there were 15 people ranging from 100 to 107 years old, of the total population of about 10,000 inhabitants. This centenarian number was more than six-fold higher the national average (15.0 vs. 2.4/10,000); the female/male ratio was 1.5 in the study area, whereas the national ratio is 4.54. Centenarians living in these villages had anthropometric measurements within normal limits and moderate sensory disability without any sign of age-related diseases, including cognitive deterioration and dementia. In addition, their clinical chemistry profile was similar to young controls and far better than that of old controls. Unequivocally, their nutritional assessment showed a high adherence to the Mediterranean nutritional profile, with low glycemic index food consumed. Overall, close adherence to Mediterranean diet seems to play a key role in age-related disease prevention and in attaining longevity.

"Positive biology": the centenarian lesson

The extraordinary increase of the elderly in developed countries underscore the importance of studies on ageing and longevity and the need for the prompt spread of knowledge about ageing in order to satisfactorily decrease the medical, economic and social problems associated to advancing years, because of the increased number of individuals not autonomous and affected by invalidating pathologies.

Centenarians are equipped to reach the extreme limits of human life span and, most importantly, to show relatively good health, being able to perform their routine daily life and to escape fatal age-related diseases. Thus, they are the best example of extreme longevity, representing selected people in which the appearance of major age-related diseases, such as cancer, and cardiovascular diseases among others, has been consistently delayed or escaped. To discuss the relevance of genetics and life style in the attainment of longevity, five papers mostly focused on Italian centenarians have been assembled in this series. The aim is to realize, through a” positive biology” approach (rather than making diseases the central focus of research, “positive biology” seeks to understand the causes of positive phenotypes, trying to explain the biological mechanisms of health and well-being) how to prevent and/or reduce elderly frailty and disability.

LPS-mediated production of pro/anti-inflammatory cytokines and eicosanoids in whole blood samples: biological effects of +896A/G TLR4 polymorphism in a Sicilian population of healthy subjects

Toll-like receptors (TLRs) are the principal mediators of rapid microbial recognition: the lipopolysaccharide (LPS) receptor TLR4 seems to have a paradigmatic role. Single nucleotide polymorphisms (SNPs) in the TLR4 gene, such as +896A/G, known to attenuate receptor signaling, have been described. The +896A/G SNP is significantly less frequent in patients with myocardial infarction, Alzheimer's disease or prostate cancer, whereas it is overrepresented in centenarians. To clarify and confirm the biological effects of +896A/G SNP and its role in the pathophysiology of age-related diseases and longevity, we assessed the levels of IL-6, TNF-α, IL-10 and eicosanoids (LTB4 and PGE2) in LPS-stimulated whole blood samples in vitro of 50 young healthy Sicilians, screened for the presence of this SNP. To evaluate the possible influence of SNPs in PTGS2 and 5-Lo genes on eicosanoid production, the enrolled individuals were also genotyped for -765G/C PTGS2 and -1708G/A 5-Lo SNPs. Both pro-inflammatory cytokines and eicosanoids were significantly lower in carriers bearing the TLR4 mutation, whereas the anti-inflammatory IL-10 values were higher. On the basis of data reported herein, some suggestions can be drawn. First, pathogen load, by interacting with the host genotype, determines the type and intensity of inflammatory responses, according to the pro-inflammatory status and tissue injury, implicated in the pathophysiology of major age-related diseases. Second, adequate control of inflammatory response might reduce the risk of these diseases, and, reciprocally, might increase the chance of extended survival in an environment with reduced antigen (that is, pathogen) load.

Association between platelet endothelial cellular adhesion molecule-1 polymorphisms and atherosclerosis: results of a study on patients from northern Italy

Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leukocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule-1 (PECAM-1), involved in this migration, has been associated with the development of atherosclerosis. Studies have investigated an association between coronary artery disease (CAD) and single-nucleotide polymorphisms (SNPs) located in functionally important domains of the PECAM-1 gene with inconsistent results. Thus, we have analyzed the distribution of V125L, N563S, and G670R SNPs in patients and controls from northern Italy, and also analyzed another functional variant identified in the 5'-untranslated region (UTR) of the PECAM-1 gene (53 G-->A). The polymorphisms of PECAM-1 were genotyped by PCR amplification with sequence-specific primers (PCR-SSP) in 119 controls and 431 CAD patients. Our results demonstrate that genotype and allele frequencies for the 53 G/A polymorphism are significantly different in patients affected by CAD compared to healthy controls, whereas, as regards the V125L and N563S polymorphisms, only the allelic frequency is significantly different. We have shown that there were a significant differences for the 53 G/A and V125L and N563S polymorphisms of PECAM-1 in patients affected by CAD compared to controls. This demonstrates a possible involvement of this gene in contributing to the development of CAD. Therefore, an understanding of the role of the PECAM-1 molecule in this complex mechanism is of pivotal significance in further development of innovative and suitable medical therapies in the future.

HLA and KIR frequencies in Sicilian Centenarians

Several studies suggest that human longevity appears to be linked inextricably with optimal functioning of the immune system, suggesting that specific genetic determinants may reside in loci that regulate the immune response, as human leukocyte antigen (HLA) and killer cell immunoglobulin-like receptor (KIR) genes. It has been suggested that longevity is associated with positive selection of alleles (i.e., HLA-DR11) or haplotypes (i.e., HLA-B8,DR3) that confer resistance to infectious disease(s). On the other hand, the cytolytic activity of natural killer (NK) cells is controlled by activating and inhibitory cell-surface receptors, including KIR. The genetic diversity of the KIR loci with respect to successful aging has been analyzed only in one study performed in the Irish population. Although two KIR genes (2DS3, 2DL5) displayed an initial increased frequency in the aged group, the significance of this association was lost when repeated in a second cohort. We have evaluated by polymerase chain reaction-sequence-specific primers (PCR-SSP) HLA-DRB1 and KIR receptors/HLA ligands frequencies in centenarians and controls from Sicily. Our results demonstrate an increase of the HLA DRB1*18 allele in male centenarians (p = 0.0266, after Bonferroni correction). Concerning KIR, no significant difference was observed after Bonferroni correction. However, our findings suggest that HLA/KIR/longevity associations are population specific, being heavily affected by the population-specific genetic and environmental history. This kind of study is important to better understand aging and longevity, hence enhancing the planning of antiaging strategies.

Polyphenols from red wine are potent modulators of innate and adaptive immune responsiveness

It is well known that the consumption of dietary polyphenols leads to beneficial effects for human health as in the case of prevention and/or attenuation of cardiovascular, inflammatory, neurodegenerative and neoplastic diseases. This review summarizes the role of polyphenols from red wine in the immune function. In particular, using healthy human peripheral blood mononuclear cells, we have demonstrated the in vitro ability of Negroamaro, an Italian red wine, to induce the release of nitric oxide and both pro-inflammatory and anti-inflammatory cytokines, thus leading to the maintenance of the immmune homeostasis in the host. All these effects were abrogated by deprivation of polyphenols from red wine samples. We have also provided evidence that Negromaro polyphenols are able to activate extracellular regulated kinase and p38 kinase and switch off the NF-kappaB pathway via an increased expression with time of the IkappaBalpha phosphorylated form. These mechanisms may represent key molecular events leading to inhibition of the pro-inflammatory cascade and atherogenesis. In conclusion, according to the current literature and our own data, moderate consumption of red wine seems to be protective for the host in the prevention of several diseases, even including aged-related diseases by virtue of its immunomodulating properties.

Pathophysiology of age-related diseases

A Symposium regarding the Pathophysiology of Successful and Unsuccessful Ageing was held in Palermo, Italy on 7-8 April 2009. Three lectures from that Symposium by G. Campisi, L. Ginaldi and F. Licastro are here summarized. Ageing is a complex process which negatively impacts on the development of various bodily systems and its ability to function. A long life in a healthy, vigorous, youthful body has always been one of humanity's greatest dreams. Thus, a better understanding of the pathophysiology of age-related diseases is urgently required to improve our understanding of maintaining good health in the elderly and to program possible therapeutic intervention.

Mechanisms of immunosenescence

On April 7,8, 2009 a Symposium entitled "Pathophysiology of Successful and Unsuccessful Ageing" took place in Palermo, Italy. Here, the lectures of G. Pawelec, D. Dunn-Walters and. G. Colonna-Romano on T and B immunosenescence are summarized. In the elderly, many alterations of both innate and acquired immunity have been described. Alterations to the immune system in the older person are generally viewed as a deterioration of immunity, leading to the use of the catch-all term immunosenescence. Indeed, many immunological parameters are often markedly different in elderly compared to young people, and some, mostly circumstantial, evidence suggests that retained function of both innate and acquired immunity in the elderly is correlated with health status. What is often not clear from studies is how far immune dysfunction is a cause or an effect. A better understanding of immunosenescence and mechanisms responsible for proven deleterious changes is needed to maintain a healthy state in later life and to design possible therapeutic interventions.