Exercise intensities modulate cognitive function in spontaneously hypertensive rats through oxidative mediated synaptic plasticity in hippocampus

Protective effects of paeonol against cognitive impairment in lung diseases

Pulmonary inflammation may lead to neuroinflammation resulting in neurological dysfunction, and it is associated with a variety of acute and chronic lung diseases. Paeonol is a herbal phenolic compound with anti-inflammatory and anti-oxidative properties. The aim of this study is to understand the beneficial effects of paeonol on cognitive impairment, pulmonary inflammation and its underlying mechanisms. Pulmonary inflammation-associated cognitive deficit was observed in TNFα-stimulated mice, and paeonol mitigated the cognitive impairment by reducing the expressions of interleukin (IL)-1β, IL-6, and NOD-like receptor family pyrin domain-containing 3 (NLRP3) in hippocampus. Moreover, elevated plasma miR-34c-5p in lung-inflamed mice was also reduced by paeonol. Pulmonary inflammation induced by intratracheal instillation of TNFα in mice resulted in immune cells infiltration in bronchoalveolar lavage fluid, pulmonary edema, and acute fibrosis, and these inflammatory responses were alleviated by paeonol orally. In MH-S alveolar macrophages, tumor necrosis factor (TNF) α- and phorbol myristate acetate (PMA)-induced inflammasome activation was ameliorated by paeonol. In addition, the expressions of antioxidants were elevated by paeonol, and reactive oxygen species production was reduced. In this study, paeonol demonstrates protective effects against cognitive deficits and pulmonary inflammation by exerting anti-inflammatory and anti-oxidative properties, suggesting a powerful benefit as a potential therapeutic agent.

Exploring the neuroprotective role of physical activity in cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a common neurological finding characterized by abnormalities of the small blood vessels in the brain. Previous research has established a strong connection between cSVD and stroke, as well as neurodegenerative disorders, notably Alzheimer's disease (AD) and other dementias. As the search for effective interventions continues, physical activity (PA) has emerged as a potential preventative and therapeutic avenue. This review synthesizes the human and animal literature on the influence of PA on cSVD, highlighting the importance of determining optimal exercise protocols, considering aspects such as intensity, duration, timing, and exercise type. Furthermore, the necessity of widening the age bracket in research samples is discussed, ensuring a holistic understanding of the interventions across varying pathological stages of the disease. The review also suggests the potential of exploring diverse biomarkers and risk profiles associated with clinically significant outcomes. Moreover, we review findings demonstrating the beneficial effects of PA in various rodent models of cSVD, which have uncovered numerous mechanisms of neuroprotection, including increases in neuroplasticity and integrity of the vasculature and white matter; decreases in inflammation, oxidative stress, and mitochondrial dysfunction; and alterations in amyloid processing and neurotransmitter signaling. In conclusion, this review highlights the potential of physical activity as a preventive strategy for addressing cSVD, offering insights into the need for refining exercise parameters, diversifying research populations, and exploring novel biomarkers, while shedding light on the intricate mechanisms through which exercise confers neuroprotection in both humans and animal models.

The protective effects of Irbesartan in cognitive impairment in hypertension

Vascular cognitive impairment (VCI) is claimed as the second most common type of dementia after Alzheimer's disease (AD), in which hypertension is a critical inducer. Currently, hypertension-induced cognitive impairment lacks clinical treatments. Irbesartan is a long-acting angiotensin receptor antagonist with promising antihypertensive properties. Our research will focus on the potential function of Irbesartan on hypertension-induced cognitive impairment. Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats were orally dosed with normal saline or 20 mg/kg/day Irbesartan for 14 consecutive days, with 4 groups divided shown as below: WKY, Irbesartan, SHR, SHR+ Irbesartan. Firstly, the markedly increased systolic blood pressure observed in SHR rats was signally repressed by Irbesartan on Day 7 and 14 post-dosing. Moreover, notably decreased time of exploring the novel object in the object recognition task (ORT) test, elevated escape latency, and reduced time in the target quadrant in the Morris water maze (MWM) test were observed in SHR rats, which were prominently reversed by Irbesartan. Furthermore, the declined superoxide dismutase (SOD) activity, elevated malondialdehyde (MDA) level, increased cyclin-dependent kinase-5 (CDK5) activity, and enhanced protein level of p35/p25, p-Tau (pSer214)/Tau46, and brain-derived neurotrophic factor (BDNF) were memorably rescued by Irbesartan. Lastly, the activity of cAMP/cAMP response element binding protein (CREB) signaling in the hippocampus of SHR rats was markedly repressed, accompanied by an upregulation of phosphodiesterase 4B (PDE4B), which was observably rescued by Irbesartan. Collectively, Irbesartan protected against the hypertension-induced cognitive impairment in SHR rats by regulating the cAMP/CREB signaling.

Cognitive Fitness: Harnessing the Strength of Exerkines for Aging and Metabolic Challenges

Addressing cognitive impairment (CI) represents a significant global challenge in health and social care. Evidence suggests that aging and metabolic disorders increase the risk of CI, yet promisingly, physical exercise has been identified as a potential ameliorative factor. Specifically, there is a growing understanding that exercise-induced cognitive improvement may be mediated by molecules known as exerkines. This review delves into the potential impact of aging and metabolic disorders on CI, elucidating the mechanisms through which various exerkines may bolster cognitive function in this context. Additionally, the discussion extends to the role of exerkines in facilitating stem cell mobilization, offering a potential avenue for improving cognitive impairment.

The Protective Effects of Policosanol on Learning and Memory Impairments in a Male Rat Model of Alzheimer's Disease

Alzheimer's disease (AD), the most common form of dementia, is characterized by a progressive decline in cognitive performance and memory formation. The present study was designed to investigate the effect of policosanol (PCO) on cognitive function, oxidative-antioxidative status, and amyloid-beta (Aβ) plaque formation in an AD rat model induced by intracerebroventricular (ICV) injection of Aβ_1-40. Healthy adult male Wistar rats were randomly divided into seven groups: control, sham (5 μL, ICV injection of phosphate-buffered saline), AD model (5 μL, ICV injection of Aβ), acacia gum (50 mg/kg, 8 weeks, gavage), PCO (50 mg/kg, 8 weeks, gavage), AD + acacia gum (50 mg/kg, 8 weeks, gavage), and AD + PCO (50 mg/kg, 8 weeks, gavage). During the ninth and tenth weeks of the study, the cognitive function of the rats was assessed by commonly used behavioral paradigms. Subsequently, oxidative-antioxidative status was examined in the serum. Moreover, compact Aβ plaques were detected by Congo red staining. The results showed that injection of Aβ impaired recognition memory in the novel object recognition test, reduced the spatial cognitive ability in the Morris water maze, and alleviated retention and recall capability in the passive avoidance task. Additionally, injection of Aβ resulted in increased total oxidant status, decreased total antioxidant capacity, and enhanced Aβ plaque formation in the rats. Intriguingly, PCO treatment improved all the above-mentioned neuropathological changes in the Aβ-induced AD rats. The results suggest that PCO improves Aβ-induced cognitive decline, possibly through modulation of oxidative-antioxidative status and inhibition of Aβ plaque formation.

Predisposition to cortical neurodegenerative changes in brains of hypertension prone rats

BACKGROUND

Substantial evidence suggests that hypertension is a significant risk factor for cognitive decline. However, it is unclear whether the genetic predisposition to hypertension is also associated with cellular dysfunction that promotes neurodegeneration.

METHODS

Changes in blood pressure were evaluated following dietary salt-loading or administration of a regular diet in Sabra Normotensive (SBN/y) and Sabra Hypertension-prone rats (SBH/y). We performed quantitative RT-PCR and immunofluorescence staining in brain cortical tissues before salt loading and 6 and 9 months after salt loading. To examine the expression of brain cortical proteins involved in the gene regulation (Histone Deacetylase-HDAC2; Histone Acetyltransferase 1-HAT1), stress response (Activating Transcription Factor 4-ATF4; Eukaryotic Initiation Factor 2- eIF2α), autophagy (Autophagy related 4A cysteine peptidase- Atg4a; light-chain 3-LC3A/B; mammalian target of rapamycin complex 1- mTORC1) and apoptosis (caspase-3).

RESULTS

Prior to salt loading, SBH/y compared to SBN/y expressed a significantly higher level of cortical HAT1 (protein), Caspase-3 (mRNA/protein), LC3A, and ATF4 (mRNA), lower levels of ATG4A (mRNA/protein), LC3A/B, HDAC2 (protein), as well as a lower density of cortical neurons. Following dietary salt loading, SBH/y but not SBN/y developed high blood pressure. In hypertensive SBH/y, there was significant upregulation of cortical HAT1 (protein), Caspase-3 (protein), and eIF2α ~ P (protein) and downregulation of HDAC2 (protein) and mTORC1 (mRNA), and cortical neuronal loss.

CONCLUSIONS

The present findings suggest that genetic predisposition to hypertension is associated in the brain cortex with disruption in autophagy, gene regulation, an abnormal response to cellular stress, and a high level of cortical apoptosis, and could therefore exacerbate cellular dysfunction and thereby promote neurodegeneration.

The impact of aerobic and resistance training intensity on markers of neuroplasticity in health and disease

OBJECTIVE

To determine the effects of low- vs. high-intensity aerobic and resistance training on motor and cognitive function, brain activation, brain structure, and neurochemical markers of neuroplasticity and the association thereof in healthy young and older adults and in patients with multiple sclerosis, Parkinson's disease, and stroke.

DESIGN

Systematic review and robust variance estimation meta-analysis with meta-regression.

DATA SOURCES

Systematic search of MEDLINE, Web of Science, and CINAHL databases.

RESULTS

Fifty studies with 60 intervention arms and 2283 in-analyses participants were included. Due to the low number of studies, the three patient groups were combined and analyzed as a single group. Overall, low- (g=0.19, p = 0.024) and high-intensity exercise (g=0.40, p = 0.001) improved neuroplasticity. Exercise intensity scaled with neuroplasticity only in healthy young adults but not in healthy older adults or patient groups. Exercise-induced improvements in neuroplasticity were associated with changes in motor but not cognitive outcomes.

CONCLUSION

Exercise intensity is an important variable to dose and individualize the exercise stimulus for healthy young individuals but not necessarily for healthy older adults and neurological patients. This conclusion warrants caution because studies are needed that directly compare the effects of low- vs. high-intensity exercise on neuroplasticity to determine if such changes are mechanistically and incrementally linked to improved cognition and motor function.

Complicated Role of Exercise in Modulating Memory: A Discussion of the Mechanisms Involved

Evidence has shown the beneficial effects of exercise on learning and memory. However, many studies have reported controversial results, indicating that exercise can impair learning and memory. In this article, we aimed to review basic studies reporting inconsistent complicated effects of exercise on memory in rodents. Also, we discussed the mechanisms involved in the effects of exercise on memory processes. In addition, we tried to find scientific answers to justify the inconsistent results. In this article, the role of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (involved in synaptic plasticity and neurogenesis), and vascular endothelial growth factor, nerve growth factor, insulin-like growth factor 1, inflammatory markers, apoptotic factors, and antioxidant system was discussed in the modulation of exercise effects on memory. The role of intensity and duration of exercise, and type of memory task was also investigated. We also mentioned to the interaction of exercise with the function of neurotransmitter systems, which complicates the prediction of exercise effect via altering the level of BDNF. Eventually, we suggested that changes in the function of neurotransmitter systems following different types of exercise (depending on exercise intensity or age of onset) should be investigated in further studies. It seems that exercise-induced changes in the function of neurotransmitter systems may have a stronger role than age, type of memory task, or exercise intensity in modulating memory. Importantly, high levels of interactions between neurotransmitter systems and BDNF play a critical role in the modulation of exercise effects on memory performance.