Effects of Regular Exercise and Intermittent Fasting on Neurotransmitters, Inflammation, Oxidative Stress, and Brain-Derived Neurotrophic Factor in Cortex of Ovariectomized Rats

Mechanisms of time-restricted feeding-induced neuroprotection and neuronal plasticity in ischemic stroke as a function of circadian rhythm

Time-restricted feeding (TRF) is known to promote longevity and brain function, and potentially prevent neurological diseases. Animal studies show that TRF enhances brain-derived neurotrophic factor (BDNF) signaling and regulates autophagy and neuroinflammation, supporting synaptic plasticity, neurogenesis and neuroprotection. Feeding/fasting paradigms influence the circadian cycle, with TRF aligning circadian cycle-related gene expression, and thus altering physiological processes. Emerging evidence highlights the role of gut microbiota in neuronal plasticity, based on the observation that TRF significantly alters gut microbiota composition. Hence, the gut-brain axis may be crucial for maintaining cognitive functions and presents a potential therapeutic target for TRF-mediated neuroprotection. In the context of ischemic stroke where neuronal damage is extensive, TRF can be a preconditioning strategy to enhance synaptic plasticity and neuronal resilience, thus improving outcomes after stroke. This review discussed the link between TRF and circadian regulation in neuronal plasticity and its implications for recovery after stroke.

The association between 'weekend warrior', regular exercise, and cognitive function in elderly individuals with and without depressive symptoms: A cross-sectional analysis from NHANES 2011-2014

BACKGROUND

While previous studies have suggested that both 'Weekend Warrior' (WW) and Regular Exercise (RE) patterns confer health benefits, the relationship between different types of physical activity (PA) and cognitive function (CF) in elderly individuals with and without depressive symptoms remains unclear.

METHODS

Our study leveraged the NHANES 2011-2014 dataset, focusing on older adults. We explore the relationship between PA and CF, stratifying by depressive status. Our statistical approach included multivariable regression analysis to identify relationships between PA levels and cognitive outcomes, along with advanced techniques such as smoothed curve fitting and threshold effect analysis to examine potential nonlinear associations and identify optimal PA pattern for cognitive health.

RESULTS

Analysis revealed a positive correlation between PA time and CF across all participants (β-depressive symptoms = 0.03, 95 % CI: 0.01-0.05; β-non-depressive symptoms = 0.01, 95%CI: 0.00-0.02). When comparing against the inactive, non-depressed participants partaking in WW showed improved cognitive scores (β-WW = 0.22, 95 % CI: 0.05-0.39), similar to those engaging in RE (β-RE = 0.15, 95 % CI: 0.09-0.21). However, among the depressed participants, significant cognitive improvements were observed in the RE (β-RE = 0.15, 95 % CI: 0.04-0.25), with the WW showing less definitive results (β-WW = 0.22, 95 % CI: -0.02-0.47).

LIMITATION

The cross-sectional nature limits causal inferences.

CONCLUSION

Our findings affirm the potential role of PA in enhancing CF among older subjects without depressive symptoms. However, only RE was associated with improved CF in those with depressive symptoms. These results are critical for crafting personalized PA guidelines to enhance cognitive health in the aging population.

Ramadan fasting and exercise combination therapy: A novel approach for osteoporosis prevention in ovariectomized rats

Background

Osteoporosis is a chronic bone metabolic disease that affects millions of people worldwide, particularly the elderly and postmenopausal women. It is characterized by weakened bones, increasing the risk of fractures and leading to significant morbidity and mortality. The goal of the current study is to examine the reported osteo-preservative effects of exercise and/or fasting in the Ramadan fasting model (RFM) in ovariectomized (OVX) rats.

Methods

The experimental intervention started 1 month following the ovariectomy procedure and consisted of five 15-min exercise sessions per week at 18-25 m/min and/or an approximately 13-h fast from sunrise to sunset (6:00 AM-19:00 PM). Serum bone metabolism biomarker levels were measured, and mineral concentrations in femoral ashed bones and digested serum were determined. Additionally, serum bone alkaline phosphatase (b-ALP), parathyroid hormone, osteocalcin, calcitonin, and vitamin D3 concentrations were measured using the competitive enzyme immunoassay technique.

Results

Calcium, magnesium, and phosphorus showed a notable decrease in mineral concentration among OVX rat femurs compared with the combination group (OVX + RFM + E) and control groups. In addition, homeostasis of serum concentrations of calcium, magnesium, and phosphorus was observed to increase in the OVX + RFM + E group rather than in the OVX group without intervention when compared with a control group. Furthermore, fasting and exercise, either alone or concurrently with ovariectomy, induced a non-significant elevation in osteocalcin, parathyroid hormone, and vitamin D3, whereas b-ALP and calcitonin increased significantly compared with those in control rats.

Conclusion

The combination of the Ramadan fasting model and moderate intensity exercises among OVX rats manifested advantageous effects in bone biomarkers compared with OVX rats without intervention. This could be recommended as a lifestyle modification that is protective against osteoporosis, especially in the context of depleted estrogen hormone after menopause.

Sericin Improves Memory Impairment Via Activation of the PKA-CREB-BDNF Signaling Pathway and Suppression of Oxidative Stress in Ovariectomized Mice

Menopause results in estrogen hormone deficiency which causes changes in brain morphology and cognitive impairments. The risk of breast and ovarian cancer increases with estrogen therapy. Thus, finding a substitute treatment option for women in menopause is necessary. In the current study, the impact of chronic sericin treatment (200 mg/kg/day for 6 weeks, gavage) on memory process, oxidative stress markers, synaptic neurotransmission, and acetylcholinesterase (AChE) activity in the hippocampus (HIP) of ovariectomized (OVX) mice was examined and compared to the effects of 17β-estradiol (Es; 20 µg/kg, s.c.). The results demonstrated that sericin and Es administration improved spatial and recognition memory of the OVX animals in the both Lashley III maze and novel object recognition tests. Moreover, sericin-treated OVX mice showed decreased ROS levels, increased endogenous antioxidant defense capacity, and decreased AChE activity in the HIP. Additionally, sericin and Es therapy up-regulated pre-and-post-synaptic protein markers and increased BDNF, CREB, and protein kinase A (PKA) protein expressions in the HIP of OVX mice. Overall, the activation of the PKA-CREB-BDNF signaling pathway by sericin can provide protection against OVX-induced cognitive dysfunction, making it a potential alternative for managing cognitive deficits in postmenopausal women.

Effect of Calorie Restriction and Intermittent Fasting Regimens on Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Humans: A Systematic Review

Background: The potential positive interaction between intermittent fasting (IF) and brain-derived neurotrophic factor (BDNF) on cognitive function has been widely discussed. This systematic review tried to assess the efficacy of interventions with different IF regimens on BDNF levels and their association with cognitive functions in humans. Interventions with different forms of IF such as caloric restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE), and the Ramadan model of intermittent fasting (RIF) were targeted. Methods: A systematic review was conducted for experimental and observational studies on healthy people and patients with diseases published in EMBASE, Scopus, PubMed, and Google Scholar databases from January 2000 to December 2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements (PRISMA) for writing this review. Results: Sixteen research works conducted on healthy people and patients with metabolic disorders met the inclusion criteria for this systematic review. Five studies showed a significant increase in BDNF after the intervention, while five studies reported a significant decrease in BDNF levels, and the other six studies showed no significant changes in BDNF levels due to IF regimens. Moreover, five studies examined the RIF protocol, of which, three studies showed a significant reduction, while two showed a significant increase in BDNF levels, along with an improvement in cognitive function after RIF. Conclusions: The current findings suggest that IF has varying effects on BDNF levels and cognitive functions in healthy, overweight/obese individuals and patients with metabolic conditions. However, few human studies have shown that IF increases BDNF levels, with controversial results. In humans, IF has yet to be fully investigated in terms of its long-term effect on BDNF and cognitive functions. Large-scale, well-controlled studies with high-quality data are warranted to elucidate the impact of the IF regimens on BDNF levels and cognitive functions.