Aging mechanisms and intervention targets

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Effects of frailty, geriatric syndromes, and comorbidity on mortality and quality of life in older adults with HIV

BACKGROUND

To understand the effects of frailty, geriatric syndromes, and comorbidity on quality of life and mortality in older adults with HIV (OAWH).

METHODS

Cross-sectional study of the FUNCFRAIL multicenter cohort. The setting was outpatient HIV-Clinic. OAWH, 50 year or over were included. We recorded sociodemographic data, HIV infection-related data, comorbidity, frailty, geriatric syndromes (depression, cognitive impairment, falls and malnutrition), quality of life (QOL) and the estimated risk of all-cause 5-year mortality by VACS Index. Association of frailty with geriatric syndromes and comorbidity was evaluated using the Cochran-Mantel-Haenszel test.

RESULTS

Seven hundred ninety six patients were included. 24.7% were women, mean age was 58.2 (6.3). 14.7% were 65 or over. 517 (65%) patients had ≥3 comorbidities, ≥ 1 geriatric syndrome and/or frailty. There were significant differences in the estimated risk of mortality [(frailty 10.8%) vs. (≥ 3 comorbidities 8.2%) vs. (≥ 1 geriatric syndrome 8.2%) vs. (nothing 6.2%); p = 0.01] and in the prevalence of fair or poor QOL [(frailty 71.7%) vs. (≥ 3 comorbidities 52%) vs. (≥ 1 geriatric syndrome 58.4%) vs. (nothing 51%); p = 0.01]. Cognitive impairment was significantly associated to mortality (8.7% vs. 6.2%; p = 0.02) and depression to poor QOL [76.5% vs. 50%; p = 0.01].

CONCLUSIONS

Frailty, geriatric syndromes, and comorbidity had negative effects on mortality and QOL, but frailty had the greatest negative effect out of the three factors. Our results should be a wake-up call to standardize the screening for frailty and geriatric syndromes in OAWH in the clinical practice.

TRIAL REGISTRATION

NCT03558438.

Vascular dementia: A microglia's perspective

Vascular dementia (VaD) is a second most common form of age-related dementia. It is characterized by cognitive impairment associated with vascular pathology, symptoms mainly caused by cerebral damage due to inadequate blood flow to the brain. The pathogenesis of VaD is complex, and a growing body of literature emphasizes on the involvement of microglia in disease development and progression. Here, we review the current knowledge on the role of microglia in regulating neuroinflammation under the pathogenesis of VaD. The commonly used animal and cell models for understanding the disease pathogenesis were summarized. The mechanisms by which microglia contribute to VaD are multifactorial, and we specifically focus on some of the predominant functions of microglia, including chemotaxis, secretory property, phagocytosis, and its crosstalk with other neurovascular unit cells. Finally, potential therapeutic strategies targeting microglia-modulated neuroinflammation are discussed.

Some Molecular and Cellular Stress Mechanisms Associated with Neurodegenerative Diseases and Atherosclerosis

Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism's nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.