Characterization of aged male BALB/ccenp mice as a model of dementia

Targeting Adenylate Cyclase: A Novel Concept for Stimulation of Neurogenesis and Pharmacotherapy of Alzheimer's Disease

BACKGROUND

The low effectiveness of existing pharmacotherapy strategies for Alzheimer's disease (AD) makes it necessary to develop a new concept for the treatment of this type of dementia. This search is promising to be carried out within the framework of the paradigm of targeting intracellular signaling pathways in Regenerative-competent Cells (RCCs).

OBJECTIVES

The purpose of the research is to study the impact of adenylate cyclase (AC) inhibitor on disorders of the psychoemotional status in aged male C57BL/6 mice, as well as on the dynamics of the content and functioning of RCCs nervous tissue.

METHODS

We examined the effect of the AC inhibitor (2',5'-Dideoxyadenosine) on conditioned reflex activity, behavioral and emotional profile in a mouse AD model (16-month-old (aged) male C57BL/6 mice), as well as the functioning of neural stem cells (NSCs), neuronal-committed progenitors (NCPs), and neuroglial cells in the subventricular zone of the cerebral hemispheres (SVZ).

RESULTS

In aged C57BL/6 mice, we found impairments in exploratory behavior, emotional reactivity, and memory, which are the characteristics of senile dementia. Therapy based on AC inhibition led to an increase in the number of NSCs and NPCs in the SVZ due to an increase in their proliferative activity. These changes were more pronounced in NCPs. At the same time, a decrease in the specialization intensity was recorded in NSCs. These phenomena developed against the background of increased secretion of neurotrophic growth factors by oligodendrocytes and microglial cells. The neuroregenerative effects of 2',5'-dideoxyadenosine correlated with the correction of age-related disorders of the psychoemotional status in aged mice.

CONCLUSION

The results provide the basis for the development of targeted drugs based on AC inhibitors to stimulate neurogenesis as an approach for the effective treatment of AD.

Intermittent cytomegalovirus infection alters neurobiological metabolism and induces cognitive deficits in mice

Risk factors contributing to dementia are multifactorial. Accumulating evidence suggests a role for pathogens as risk factors, but data is largely correlative with few causal relationships. Here, we demonstrate that intermittent murine cytomegalovirus (MCMV) infection of mice, alters blood brain barrier (BBB) permeability and metabolic pathways. Increased basal mitochondrial function is observed in brain microvessels cells (BMV) exposed to intermittent MCMV infection and is accompanied by elevated levels of superoxide. Further, mice score lower in cognitive assays compared to age-matched controls who were never administered MCMV. Our data show that repeated systemic infection with MCMV, increases markers of neuroinflammation, alters mitochondrial function, increases markers of oxidative stress and impacts cognition. Together, this suggests that viral burden may be a risk factor for dementia. These observations provide possible mechanistic insights through which pathogens may contribute to the progression or exacerbation of dementia.

Once-Daily Subcutaneous Irisin Administration Mitigates Depression- and Anxiety-like Behavior in Young Mice

Major depression is one of the most common psychiatric disorders worldwide, usually associated with anxiety. The multi-etiological nature of depression has increased the search for new antidepressant molecules, including irisin, for which, in a previous study, we tested its effect in young mice when administered intraperitoneally in a long-term intermittent manner. Here, we evaluated the effect of subcutaneous short-term irisin administration (100 µg/Kg/day/5 days) in male and female mice subjected to behavioral paradigms: Tail Suspension Test (TST), Forced Swim Test (FST), Elevated Plus Maze (EPM), and Y Maze (YM). Moreover, a qRT-PCR assay was performed to analyze the impact of irisin treatment on Pgc-1α/FNDC5 expression in the brain. A significant reduction in immobility time in TST and FST was observed in irisin-treated mice. Furthermore, irisin treatment significantly increased the number of entries and time spent in open arms, demonstrating its anxiolytic effect. Memory-enhancing effects were not reported in YM. Interestingly, no gender differences were observed in all behavioral tests. Overall, these results suggest that short-term subcutaneous irisin administration can exert an antidepressant and anxiolytic role, probably due to the activation of the Pgc-1α/FNDC5 system in the brain. Further investigation could lead to the identification of irisin as a new agent for the treatment of psychiatric disorders.

Long-Term Supplementation of Syzygium cumini (L.) Skeels Concentrate Alleviates Age-Related Cognitive Deficit and Oxidative Damage: A Comparative Study of Young vs. Old Mice

The Syzygium cumini (L.) Skeels is reported to have medicinal properties, but its benefits on age-related neurological changes have not been previously explored. In the current study, after phytochemical analysis of the pulp of Syzygium cumini (L.) Skeels fruit (Sy. cmi), young BALB/c mice have been supplemented with its 5, 15, and 30% dilution for 16 months, followed by behavioral experimentation and biochemical evaluation of isolated brains. The Sy. cmi has been found enriched with phenols/flavonoids while the occurrence of nine phytocompounds has been identified through GC-MS analysis. Further, Sy. cmi supplementation has caused significant (p < 0.05) protection from anxiety-like behavior in aged mice, and they have explored open, illuminated, and exposed areas of open field, light/dark, and an elevated plus maze, respectively. Furthermore, these animals have shown improved cognitive abilities as their percent (%) spontaneous alteration and novelty preference are significantly greater in T-maze and Y-maze and familiarity/novelty recognition tests. Further, Sy. cmi-supplemented mice remember the aversive stimuli zone and escape box location in passive avoidance and Barnes maze tests, and their brains have low levels of malondialdehyde and acetylcholinesterase with elevated antioxidant enzymes. The outcomes have provided scientific insight into the beneficial effects of Sy. cmi on age-associated amnesia that might be attributed to antioxidant and anticholinergic effects exerted by phytocompounds (caryophyllene, humulene, β-Farnesene, and phytol) owned by Syzygium cumini.

The Effect of Mango Mistletoes (Dendrophthoe pentandra) Leaves Extract on Percentage of CD4+CD28+, CD8+CD28+, and interleukin-2 Levels of Aged Balb/c Mice

BACKGROUND: Population aging is considered to be a global phenomenon today. Age-associated immune system dysfunction or “immunosenescence” is indicated by increased susceptibility to infections and chronic diseases, such as hypertension, diabetes mellitus, autoimmune diseases, heart disease, and atherosclerosis. One of the immunosenescence markers is a significant drop in CD28 and reduced proinflammatory cytokine interleukin-2 (IL-2). The mango mistletoes are deemed to have a better affinity for docking the CD28 and IL-2R receptors of α and β subunits than other plants. AIM: This study aims to determine the effect of ethanol extract of mango mistletoes on IL-2 levels, the percentage of CD4+CD28+, and the percentage of CD8+CD28+ in aged female mice. METHODS: The leaves of mango mistletoes were extracted using 96% ethanol solvent, and the extract was administered to aged female mice (18–20 months) orally with different doses for each group, namely 150, 300, and 600 mg/kg. Mango mistletoe leaves extract was administered once a day for 14 days. Then, the IL-2 levels of the mice were checked from their heart blood samples using Enzyme-Linked Immunosorbent Assay, while the percentages of CD4+CD28+ and CD8+CD28+ were examined from the spleen samples using flow cytometry. RESULTS: The ethanol extract of mango mistletoe leaves was able to increase the percentage of CD4+CD28+ significantly (p < 0.05) at doses of 300 and 600 mg/kg and increase the percentage of CD8+CD28+ significantly (p < 0.05) at a dose of 600 mg/kgBW, while other various doses had a strong enough correlation (r = 0.48) to increase IL-2 levels. CONCLUSION: The ethanol extract of mango mistletoe leaves has the good potential to inhibit the aging process in the immune system, as characterized by an increase in IL-2 levels and the percentage of CD4+CD28+ and CD8+CD28+.

Anionic Polyelectrolyte Hydrogel as an Adjuvant for Vaccine Development

Vaccination is one of the main methods for the specific prevention of infectious diseases. The disadvantage of vaccination is the use of pathogens (live or attenuated viruses and bacteria) that can lead to the development of a disease. Recombinant technologies are capable of producing specific DNA or protein molecules that possess antigenic properties and do not cause disease. However, individual antigen molecules are low-immunogenic, and therefore, require conjugation with a compound possessing stronger immunogenic properties. In this study, we examined the immunogenic properties of the new anionic copolymer consisting of glycidyl methacrylate, butyl acrylate, triethylene glycol dimethacrylate, and acrylic acid, in mice. The experimental polymer induced a stronger immunogenic response than aluminum hydroxide. The histological studies have established that immunization both with aluminum hydroxide and the polymer studied does not cause damage to the liver, kidneys, or the spleen. No negative side effects were observed. It has been concluded that the new synthetic anionic polyelectrolyte hydrogel (PHG) has a potential as an adjuvant for vaccine development.