Current Pharmaceutical Design - Volume 16, Issue 6, 2010

Due to the high number of age-dependent diseases and the complexity of the therapeutic interventions this hot topic has been splitted into two parts. In Part I the physiopathology of immunosenescence; the age-related diseases and therapeutic attempts; the mechanisms of neurodegeneration; the relationship between cancer and ageing will be discussed. Candore and associates [1] will review the main mechanisms of low grade inflammation and related diseases in aging. Pinti and associates [2] and Colonna-Romano and associates [3] will illustrate the T cell homeostasis and the B cell compartment in centenarians, respectively. Cevenini and associates [4], Guiglia and associates [5], Abate and associates (6), Campisi and associates [7] and Giannola and associates [8] will discuss on new anti-ageing therapeutics with special reference to innovative sites of drug delivery. Govoni and associates [9] Mura and associates [10], Di Bona and associates [11], Alcaro and associates [12], Lanni and associates [13] will focus on the senescence of the brain and on new anti-Alzheimer agents. Balistreri and associates [14], Menna and associates [15], Moseniak and Sikora [16] and Petta and Craxì [17] will discuss on the cancer risk and proinflammatory genotypes as well as cancer prevention.

Nowadays, people are living much longer than they used to do, however they are not free from ageing. Ageing, an inexorable intrinsic process that affects all cells, tissues, organs and individuals, is a post-maturational process that, due to a diminished homeostasis and increased organism frailty, causes a reduction of the response to environmental stimuli and, in general, is associated to an increased predisposition to illness and death. However, the high incidence of death due to infectious, cardiovascular and cancer diseases underlies a common feature in these pathologies that is represented by dysregulation of both instructive and innate immunity. Several studies show that a low-grade systemic inflammation characterizes ageing and that inflammatory markers are significant predictors of mortality in old humans. This pro-inflammatory status of the elderly underlies biological mechanisms responsible for physical function decline and agerelated diseases such as Alzheimer's disease and atherosclerosis are initiated or worsened by systemic inflammation. Understanding of the ageing process should have a prominent role in new strategies for extending the health old population. Accordingly, as extensively discussed in the review and in the accompanying related papers, investigating ageing pathophysiology, particularly disentangling agerelated low grade inflammation, is likely to provide important clues about how to develop drugs that can slow or delay ageing.

The immune system undergoes a process of profound remodelling during aging, referred to as immunosenescence, and characterized by complex modifications of several components. In this review, we discuss recent developments and observations regarding the generation of T cells in the thymus during aging and longevity, and the regulation and maintenance of peripheral blood lymphocytes. The generation of new T cells is indeed crucial to maintain a functional immune system, and is a fundamental step to avoid unsuccessful aging, thus reaching longevity in good health. Mechanisms will be described that are related to the production and maintenance of those lymphocytes defined “recent thymic emigrants”, and to the detection of the so called “T cell receptor rearrangement excision circles (TREC)”, along with the presence in the periphery of naïve and memory T cells, that can be influenced and regulated by several different mechanisms. Several strategies aimed at improving thymic functionality are currently receiving a growing interest, and some of them are based on molecules that are produced by, and/or act on immune cells. Data on the possible use of these molecules, including cytokines like interleukin (IL)-7, IL-15 and keratinocyte growth factor, to restore thymic function are reviewed and discussed.

Immunosenescence is considered a major contributory factor to the increased frequency of morbidity and mortality among elderly. On the other hand centenarians are considered the best example of successful ageing. To gain insight into mechanisms of immunosenescence and its clinical relevance, a possible model is represented by centenarians and/or their offspring. Nowadays centenarians are not more a curiosity, but in Europe are 1/8000 inhabitants and it has been demonstrated that the centenarian offspring, who are typically in their 70s and 80s, have a survival advantage when compared with age-matched controls whose parents died at an average life expectancy. Then again, studies on immunosenescence focus mainly on T cell impairment, although B cells are also affected. So, in the present preliminary report, we have studied B cell compartment in two classes of individuals, old people and centenarian offspring. B cell compartment was analysed using anti-IgD and CD27 antibodies which characterize naive B cells (IgD+ CD27-), memory unswitched B cells (IgD+CD27+), memory switched B cells(IgD-CD27+) and double negative B cells (DN) (IgD-CD27-), i.e. exhausted memory cells. As expected, in both cohorts we observed a decreased B cell count. However, in centenarian offspring, naïve B cells are more abundant whereas exhausted memory cells (DN B cells, IgD-CD27-) do not show the increase that we have previously demonstrated in healthy elderly donors. These data are similar to that found in previously experiments on young subjects. So, our preliminary results show that centenarian offspring do not have the typical trend of memory/naive B cell subsets observed in elderly people and this is in agreement with the higher levels of IgM in the serum of centenarian offspring in comparison with data obtained in age-matched controls. This reservoir of naive B cell might be one of the causes that make centenarian offspring able to keep fighting off new infections, hence prolonging their life. So, B cell subset changes could represent a hallmark of successful or unsuccessful ageing and could be used as a biomarker of human life span, potentially useful for the evaluation of anti-ageing treatment.

A typical feature of ageing is a chronic, low-grade inflammation characterized by a general increase in the production of proinflammatory cytokines and inflammatory markers (“inflamm-ageing”). This status may slowly damage one or several organs, especially when unfavorable genetic polymorphisms and epigenetic alterations are concomitant, leading to an increased risk of frailty together with the onset of age-related chronic diseases. The contribution of different tissues (adipose tissue, muscle), organs (brain, liver), immune system and ecosystems (gut microbiota) to age-related inflammation (“inflamm-ageing”) will be discussed in this review in the context of its onset/progression leading to site-restricted and systemic effects. Moreover, some of the possible strategies and therapies to counteract the different sources of molecular mediators which lead to the age-related inflammatory phenotype will be presented.

Changing demographics, including an increase in life expectancy and the growing numbers of elderly has recently focused attention on the need for geriatric dental care. Ageing affects oral tissues in addition to other parts of the human body, and oral health (including oral mucosa, lips, teeth and associated structures, and their functional activity) is an integral component of general health; indeed, oral disease can cause pain, difficulty in speaking, mastication, swallowing, maintaining a balanced diet, not to mention aesthetical considerations and facial alterations leading to anxiety and depression. The World Health Organization recommends the adoption of certain strategies for improving the oral health of the elderly, including the management and maintenance of oral conditions which are necessary for re-establishing effective masticatory function. Oral health is often neglected in the elderly, and oral diseases associated with aging are complex, adversely affecting the quality of life. Although oral health problems are not usually associated with death, oral cancers result in nearly 8,000 deaths each year, and more than half of these occur at an age of 65 years plus. This report, which is dedicated to geriatric physicians, geriatric dentistry and specialists in oral medicine reviews age-related oral changes in elderly patients and efforts to summarize the effects of aging in hard and soft oral tissues.

Osteoarthritis (OA) is very disabling condition in the elderly. The current therapeutic approaches (analgesics, NSAIDs, COX-2 inhibitors, steroids) do not delay the OA progression or reverse joint damage. Moreover, they may cause relevant systemic side effects. Hyaluronic acid (HA) is a physiologic component of the synovial fluid and is reduced in OA joints. Therefore, intra-articular injection of HA, due to its viscoelastic properties and protective effect on articular cartilage and soft tissue surfaces of joints, can restore the normal articular homoeostasis. These effects are evident when HA is properly administered into the articular space; therefore, the use of “imageguided” infiltration techniques is mandatory. Viscosupplementation (VS), with different HA preparations (Low and High molecular weight), can be considered when the patient has not found pain relief from other therapies or is intolerant to analgesics or NSAIDs. A 3-5 doses regimen is usually recommended with 1 week interval between each injection. Several studies have shown the efficacy of HA for the treatment of knee OA, with positive effects on pain, articular function (Western Ontario and Mc Master Universities Osteoarthritis Index [WOMAC], Lequesne Index [LI], Range of Motion [ROM]), subjective global assessment and reduction in NSAIDs consumption. In general, the benefit is evident within 3 months and persists in the following 6-12 months. Encouraging but inconclusive results have also been observed for the treatment of shoulder, carpo-metacarpal, hip and ankle OA. However there is the need of better designed studies to prove the effectiveness of these medications, in order to rule out a placebo effect. The therapy is well tolerated with absence of systemic side effects and only with limited local discomfort.

The authors review the ultra-structural aspects and permeability features of normal human oral mucosa, after having recently tested and used it as a new site of systemic drug delivery. The pertinent scientific literature from 1975 through 2009 has been analysed and discussed. Buccal epithelium is a relatively permeable, robust non-keratinized tissue and blood vessels drain directly into the jugular vein; due to its particular features, it has been of increasing interest to researchers as an alternative site of drug administration. The review describes the structure and function of the buccal mucosa, the rationale for transbuccal drug delivery and the main transmucosal drug delivery systems. Recent studies have investigated the delivery of a variety of drugs through the buccal mucosa in order to assess both local and systemic, either positive or adverse, effects. In conclusion, buccal mucosa may be considered a promising site for effective, safe and non-invasive transmucosal sustained drug delivery.

The transbuccal delivery of drugs could assist several categories of chronic, especially elderly, patients in adhering to a correct dosage regimen. In particular, patients suffering from dementia have several difficulties in following the prescribed dosage, in addition to problems associated with swallowing tablets. Galantamine is currently used for treating patients with mild to moderate Alzheimer's-type dementia. The transbuccal delivery of this drug could be an interesting non- invasive and safe administration route. Several studies have been performed in vitro and ex vivo within the framework of a European Commission funded Project (IntelliDrug-FP6), aimed at developing a device which would be fitted for controlled delivery of drugs by an electronic and software-driven system. The primary objective of this study was to evaluate the efficacy of a prototype of the IntelliDrug device in vivo on 6 pigs, following a single Galantamine dose to be delivered through the buccal mucosae, as compared to intravenous drug injection. The secondary objectives were: a) to verify Galantamine bioavailability through buccal delivery; b) to evaluate the permeation enhancement effect of iontophoresis; and, finally, c) to assess any histomorphological changes in the buccal mucosae after transbuccal delivery. The results suggested that transbuccal delivery has the potential to cause long-lasting and controlled blood levels of Galantamine. The latter crosses the entire buccal mucosae, reaching systemic circulation after about 30 minutes and its plasmatic peak approximately 120 minutes after administration. The histological analysis of the buccal mucosae did not reveal any evidence of flogosis or tissue injury. Our results have clearly confirmed that the buccal delivery of Galantamine is a reliable tool with which to overcome the drawbacks associated with the conventional administration route. In general, transbuccal drug delivery has been shown to be an interesting, noninvasive and safe administration route for delivering systemically-acting drugs.

Ageing is characterized by alterations in brain anatomy and physiology, finally contributing to an impairment in cognitive functions, such as memory. The most relevant observations indicate that senescent-related cognitive decline is not only due to neuronal loss, instead, functional changes occurring over time play a key role. Overall, these modifications are indeed responsible for an altered interneuronal communication that can represent, rather than morphological modifications, the primum movens leading to cognitive decline. Among the age-induced changes underlying alterations in neuronal communication and synaptic plasticity, those related to neurotransmitter/neurotrophin systems and downstream signalling pathways are of great relevance. In particular, considering that protein kinases play a strategic role aimed to convert the extracellular signals into biological responses, functional alterations on kinases may directly contribute to age-dependent neuronal dysfunctions. Within this context, numerous studies point out on several kinases as positive regulators for memory function and suggest that various memory disturbances are the result of a deficit in kinase signalling pathways. Many kinases associated with synaptic function are indeed age-sensitive; in fact, various studies in senescent animals indicate that a reduction in kinases expression/function in some brain areas correlates with ageing and memory decline. In line with these concepts, pharmacological modulation of kinases may lead to neuroprotective effects that can prevent or counteract age-related memory impairment. This review will mainly focus on the age-induced changes on Protein Kinase C (PKC), Protein Kinase A (PKA), Calcium/calmodulin-dependent Protein Kinase (CaMK), Tyrosine Kinase, widely accepted as key actors in signalling pathways associated with memory.

The amyloid cascade hypothesis sustains that beta-amyloid (Aβ) is the main pathogenetic factor of Alzheimer's Disease (AD). Although the direct and indirect neurotoxic role of Aβ are unchallenged, recent findings suggest that the peptide may have so far unforeseen physiological roles. In this regard, the observations showing the ability of Aβ to exert synaptic activities in absence of neurotoxicity are very intriguing. In particular, the peptide is able to affect synaptic transmission of different neurotransmitter systems in key brain areas that regulate executive and cognitive functions, an observation that points Aβ as a new neuromodulator. However, in a pathological context, Aβ may drive functional alterations of several neurotransmitter systems in the early phases of the disease, in turn producing subtle cognitive and behavioural disturbances in addition and before the well known neurodegenerative events. On the other hand, advancing age is the most significant risk factor for the development of AD. In fact, during aging increased Aβ levels have been reported. Moreover, several neurotransmitter systems undergo age-related changes in parallel to a decline of cognitive functions. However, the putative neuromodulatory role of Aβ in the context of aging is nowadays unknown. For these reasons, future studies about the spectrum of action of Aβ (brain areas and neurotransmitter systems affected) are particularly interesting since may suggest new therapeutic targets in order to sustain those functions which may be altered during aging.

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. AD has been linked to inflammation and oxidative stress. Neuro-pathological hallmarks are senile plaques, resulting from the accumulation of several proteins and an inflammatory reaction around deposits of amyloid, a fibrillar protein, Aβ, product of cleavage of a much larger protein, the beta-amyloid precursor protein (APP) and neurofibrillary tangles. Inflammation clearly occurs in pathologically vulnerable regions of AD and several inflammatory factors influencing AD development, i.e. environmental factors (pro-inflammatory phenotype) and/or genetic factors (pro-inflammatory genotype) have been described. Irrespective of the source and mechanisms that lead to the generation of reactive oxygen species, mammalian cells have developed highly regulated inducible defence systems, whose cytoprotective functions are essential in terms of cell survival. When appropriately activated, each one of these systems has the possibility to restore cellular homeostasis and rebalance redox equilibrium. Increasing evidence support the notion that reduction of cellular expression and activity of antioxidant proteins and consequent augment of oxidative stress are fundamental causes for ageing processes and neurodegenerative diseases, including AD. The better understanding of different molecular and cellular inflammatory mechanisms is crucial for complete knowledge of AD pathophysiology, hence for its prevention and drug therapy. Accordingly, two lines of preventive therapeutics can be outlined, the first based on anti-inflammatory drugs, the second one on anti-oxidative properties.

In this manuscript we report an integrated study to develop simple choline esters as cholinergic agents potentially useful against the Alzheimer disease. In previously reported experiments we demonstrated the capability of the pivaloylcholine to exert cholinergic effects into the Central Nervous System, so we decided to explore small variants of choline esters. The knowledge of crystallographic models of the enzymes involved in the hydrolysis of the acetylcholine allowed to consider the steric compatibility of some choline derivatives within their catalytic sites. The purpose of the work was to find out analogues with increased selectivity toward the acetylcholinesterase versus the butyrrylcholinesterase. Theoretical models were compared to enzymatic tests carried out with both enzymes and two different methods. In this screening we have selected two candidates for the in vivo experiments with pre-treated rats. Their electroencephalographic profiles were recorded and averaged before and after the intraperitoneal treatment with two compounds in comparison to the pivaloyl lead ester. The results demonstrated that one of the esters can exert biological effects similar to the parent compound.

Multiple molecular, cellular, structural and functional changes occur in the brain during aging. Neural cells may respond to these changes adaptively by employing multiple mechanisms in order to maintain the integrity of nerve cell circuits and to facilitate responses to environmental demands. Otherwise, they may succumb to neurodegenerative cascades that result in disorders such as Alzheimer's and Parkinson's diseases. An important role in this balancement is played by neurotrophic factors, which are central to many aspects of nervous system function since they regulate the development, maintenance and survival of neurons and neuron-supporting cells such as glia and oligodendrocytes. A vast amount of evidence indicates that alterations in levels of neurotrophic factors or their receptors can lead to neuronal death and contribute to aging as well as to the pathogenesis of diseases of abnormal trophic support (such as neurodegenerative diseases and depression) and diseases of abnormal excitability (such as epilepsy and central pain sensitization). Cellular and molecular mechanisms by which neurotrophic factors may influence cell survival and excitability are also critically examined to provide novel concepts and targets for the treatment of psysiological changes bearing detrimental functional alterations and of different diseases affecting the central nervous system during aging.

Host genetic factors are crucial risk determinants for many human cancers. In this framework, an interesting model is represented by prostate cancer (PC), which is featured by a complex pathophysiology with a strong genetic component. Multiple genes seem to influence PC risk and several single nucleotide polymorphisms (SNPs) of candidate genes modifying PC susceptibility have been identified. It is noteworthy the potential association of common SNPs in pro-inflammatory genes with PC risk, since chronic inflammation is assumed to play a key role in prostate carcinogenesis. With the aim to identify candidate genes as an experimental basis to develop new strategies for both prevention and treatment of PC, we have investigated the potential role of common SNPs of a gene cluster (TLR4, TLR2, PTGS2 and 5-Lo), involved in innate and inflammatory response, in PC cases, age-matched controls and centenarians from Sicily. Six SNPs were genotyped and their association with PC risk determined. Statistical analysis evidenced a significant association of some pro-inflammatory gene SNPs with an increased risk of PC. Furthermore, significant differences were observed comparing the three groups in the combined presence of a “high responder” pro-inflammatory profile. Overall, the present results suggest the likely association of these SNPs and PC risk, clearly motivating the need of larger studies to confirm the role of these genes in PC development and/or progression.

It is well established that an increase of n-6 polyunsaturated (i.e. arachidonic and arachidonic-converted linoleic acids) fat dietary intake enhances carcinogenesis and promotes tumorigenesis through oxidative metabolism. The Cyclooxygenase (COX) and Lipoxygenase (LOX) enzymes mediate the oxidative metabolism of n-6 polyunsaturated fatty acids and generate a cascade of biological active molecules. Nonsteroidal antinflammatory drugs (NSAIDs) modulating arachidonic acid (AA) metabolism have been utilized in cancer chemoprevention. The gastrolesivity of a prolonged use of nonselective NSAIDs, due to the COX inhibition, an important housekeeping gene of the gastrointestinal system, contraindicated their use in chemoprevention. Moreover, cardiovascular side effects emerged in the long-term use of COX-2 specific inhibitors rising doubts on their use for cancer chemoprevention. This evidence renewed the interest into other AA-metabolizing pathways relevant in inflammation and carcinogenesis. Here, the role of the LOXs pathways in carcinogenesis is reviewed. Inhibition of the LOX pathways, alone or in association with COX-2 pathway, appears to be a promising field for detecting new molecular target and engineering new chemopreventive strategies on cancer.

Polyploidy, a state of increased number of chromosomes, occurs often in plants and less frequently in animals. Polyploidization is recognized as a part of a developmental program and can be achieved via different mechanisms bypassing certain stages of the cell cycle. However, polyploidization also accompanies some pathological conditions as well as ageing. It is believed that tetraploid cells precede aneuploid ones in the early phases of tumor development. Division of tetraploid cells is restricted by the active tetraploid (4N G1) checkpoint. Tetraploid cells that are able to overcome this checkpoint give rise to increased genomic instability and tumor progression. Recently a cellular senescence program activated by oncogene expression was shown to act as a natural barrier against cancer development. Senescent cells were detected in many benign, but not malignant, human and animal tumors. Senescence can actually block cell transformation provided the 4N G1 checkpoint is active. Cancer cells that escaped the 4N G1 block are still able to undergo senescence upon anticancer treatment. Induction of cancer cell senescence is often correlated with high ploidy formation. Some polyploid cells can escape senescence and give progeny with numerical changes of chromosomes. Divisions of polyploid cancer cells on the road to senescence can be responsible for the ineffectiveness of anticancer therapy. Altogether, this implies polyploidy as a link between cellular senescence, cancer development and possible cancer renewal after treatment.

Hepatocellular carcinoma (HCC) is the most frequent primary neoplasm of the liver, and is the fourth most common malignancy worldwide. It is also the third leading cause of cancer-related deaths. Most cases of HCC develop on a pre-existing chronic liver disease, usually due to hepatitis C virus (HCV), hepatitis B virus (HBV), or alcohol. However, between 15% and 50% of HCC develops in the absence of a known etiology of liver disease, and different lines of evidence identify in non-alcoholic fatty liver disease (NAFLD) a possible relevant risk factor for occurrence of HCC. Insulin resistance (IR), steatosis, oxidative stress and imbalances in adipokine/cytokine interplay, the most important factors involved in NAFLD pathogenesis and progression, could also have a determinant role in liver carcinogenesis by promoting cellular growth and DNA damage. Recently, behavioral therapy and various insulin sensitizing agents have been tested in the treatment of NAFLD. A number of studies suggest that these approaches improve IR and reduce steatosis, necroinflammation and fibrosis. A potential role of these therapeutic strategies in the prevention of hepatocarcinogenesis can thus be envisaged.