Brain aging is part of the aging of the whole body, largely determining the success of general aging and the quality of life of an older person. Brain aging is a complex multifactorial process that occurs throughout a human’s life, which includes changes at subcellular, tissue, and organ levels as well as at physiological level, mediating changes in neurophysiological (cognitive) functions. The review provides up-to-date data on morphological and physiological changes observed during natural aging; various phenotypes of brain aging are discussed, including both pathologically accelerated and «supernormal» aging; questions of the division between the norm and pathology are raised in the context of changes observed during brain aging; the factors both accelerating and decelerating the aging processes of the brain are considered along with linkage of natural aging with neurodegenerative and cerebrovascular diseases.

   Despite the fact that more than 90 % of tryptophan is metabolized via the kynurenine pathway, the serotonin pathway is of great importance for the functioning of the central nervous system. The main products of this pathway are serotonin and melatonin. They provide maintenance of the sleep-wake mode, modulation of oxidative stress activity, apoptosis of neurons and glial elements, regeneration and neuroinflammation. In the pathogenesis of Alzheimer's disease, neuroinflammation plays one of the main roles. Melatonin and serotonin, being modulators of its intensity, as well as an important component of neurochemical interactions that provide cognitive functions, can be considered as targets for preventive and therapeutic effects.

   The process of aging is a complex biological phenomenon that is influenced by multiple factors, including genetics, environment, and lifestyle. Recent studies have shown that epigenetic modifications play an important role in the aging process, as they regulate gene expression and ultimately affect cellular function. Epigenetic modifications include DNA methylation, histone modification, and non-coding RNA expression, among others. The authors of the review discuss the role of DNA methylation in regulating gene expression and its relationship to age-related diseases such as cancer and neurodegeneration. Also, the role of histone modification and its impact on chromatin structure and gene expression is reviewed in the article. Additionally, review provides information on involvement of molecular hallmarks of aging in age-related diseases. Understanding the role of epigenetic mechanisms in aging is crucial for developing new interventions that could potentially slow down or even reverse the aging process.

   Human aging is associated with an increased risk of various geriatric syndromes, cognitive impairment being among the most frequent. The most prominent form of the cognitive impairment — dementia — has become one of the major course of dependency in older and oldest old patients. Nevertheless, it has been shown that despite the fact that various parts of the brain change structurally over time due to natural aging or diseases, it does not necessarily manifest into clinical symptoms for some older people. Therefore, there is a dissociation of the severity of morphological and functional brain changes. The review presents current data on adaptive mechanisms that ensure the preservation of neurocognitive activity during aging process. In addition to the concept of brain and cognitive reserves, different mechanisms of neurocognitive maintenance and compensation are discussed, both in the norm and in the development of Alzheimer's disease. The possibility of their clinical and instrumental assessment and practical significance are discussed.

   Aim. To evaluate the association between telomere length and frailty and individual geriatric syndromes in older adults.

   Materials and methods. The database of a hundred-year-old citizen of the city of Moscow was analyzed. The analysis was carried out using the data driven from the Comprehensive Geriatric Assessment (CGA), in particular, Age is not a Hindrance Scale, the Barthel index, Instrumental Activities of Daily Living (IADL), Mini Nutritional Assessment (MNA), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS-15). DNA was isolated from frozen blood and a study of telomere length was performed. The comparison of telomere length in groups of patients with frailty and individual geriatric syndromes was carried out.

   Results. The study involved 60 people (98±1.8 years, 86.7% women). The analysis found no differences in telomere length in study participants with and without frailty, as well as in the analysis of individual geriatric syndromes. No correlation was found between telomere length and the results of comprehensive geriatric assessment scales. There was no difference in telomere length in patients who died within 3 years of follow-up and no.

   Conclusion. No relationship was found between telomere length and frailty. Thus, telomere length cannot be considered as a reliable biomarker of functional aging.

   Background. Age-related changes associated with the decrease in health and autonomy drastically increase the cost of medical care, maintenance and treatment. Late detection of ilnesses is the root cause of escalating the economic weight from age-related diseases, causing a surge in costs for the recovery, treatment and care of those needing outside assistance. One of the age-associated diseases is Alzheimer's disease. Alzheimer's disease is one of the many manifestations of age-related dementia, accompanied by a violation of human cognitive abilities. This cluster of diseases does not affect other systems (cardiovascular, musculoskeletal, digestive), and they can operate normally. An important effect of this disease for society is the impossibility of conducting a full-fledged work activity, as memory, attention, etc. are disturbed. That is, with absolutely normally functioning body systems, a person cannot perform the simplest operations. Another important feature is the lack of an effective way to treat this disease. The pathogenesis is so complex that today there is no method of treatment aimed at all links. Also of great importance is the timeliness of detection of this disease. Due to the fact that recently there were test systems and express diagnostics for the early detection of Alzheimer's disease, it became possible to start treatment earlier, which increased the chances of recovery and reduced treatment costs in case of diagnosing moderate and severe Alzheimer's disease gravity.

   Aim. Revealing the difficulties of assessing the economic burden of Alzheimer's Disease.

   Materials and methods. To identify the difficulties of assessing the economic burden, free sources, publications on Alzheimer's disease, data from clinical guidelines, the standard for providing medical care to elderly and senile patients with cognitive disorders, information on maximum selling prices registered and included in the State Register of Vital and Essential Drugs Prices, statistical data, compulsory health insurance tariffs.

   Results. The main problematic issues of the difficulty of assessing the economic burden of Alzheimer's disease are identified.

   Conclusion. Diseases of the nervous system are of particular importance for the health of the patient, since disorders affecting this system do not allow the patient to fully and fully fulfill their labor duties. In this regard, the development of a method for assessing the cost-effectiveness of Alzheimer's disease, as one of the most common disorders of cognitive functions, is an extremely important social task aimed at optimizing the treatment process, early detection and effective treatment aimed at recovery.