GlyNAC (Glycine and N-Acetylcysteine) Supplementation in Old Mice Improves Brain Glutathione Deficiency, Oxidative Stress, Glucose Uptake, Mitochondrial Dysfunction, Genomic Damage, Inflammation and Neurotrophic Factors to Reverse Age-Associated Cognitive Decline: Implications for Improving Brain Health in Aging

Gut microbiota and blood metabolites: unveiling their roles in hippocampal volume changes through Mendelian randomization and mediation analysis

Changes in hippocampal volume (HV) are linked to various neuropsychiatric disorders. Observational studies suggest associations of gut microbiota (GM) and blood metabolites (BM) with changes in HV; however, their causal relationships remain unclear. We aimed to use Mendelian randomization (MR) to investigate the causal associations of GM and BM with changes in HV and to explore the potential mediating role of BM. Using two-sample MR (TSMR) analysis, we examined 412 GM traits and 1,400 BM traits with a focus on their causal relationships with age-independent/dependent longitudinal changes in HV, primarily using the inverse variance weighted method. Furthermore, we explored the mediating role of BM through a two-step MR design. We identified 44 GM traits and 175 BM traits having nominally significant causal associations with age-independent/dependent longitudinal changes in HV. In addition, the glycine-to-pyridoxal ratio (mediation proportion: 7.38%) and the phosphate-to-citrate ratio (mediation proportion: 12.55%) mediated the effect of the pathway of L-arginine degradation II on the reduction of age-independent longitudinal changes in HV. Our study reveals the causal effects of GM and BM on longitudinal changes in HV and identifies BM traits with mediating roles. These findings offer valuable insights for the prevention and treatment of the related neuropsychiatric disorders.

The mechanism of lycopene alleviating cadmium-inhibited glucose uptake ability of epithelioma papulosum cyprini cells: miR-375, oxidative stress, and actin cytoskeleton dysfunction

Cadmium (Cd) poses a threat to fish and human health. Carp is the most widely farmed fish, and it is necessary to study the mechanism of Cd toxicity and effective mitigation methods for Cd poisoning in carps. We previously found that Cd up-regulated miR-375 in common carp spleens, and that IRS1, a factor involved in glucose (GLU) uptake, was a potential target gene of miR-375. However, whether Cd can decrease GLU uptake ability in fish remains unknown. Oxidative stress (OS) and actin cytoskeleton dysfunction (ACD) can take part in the mechanisms of GLU uptake ability reduction. Lycopene (Lyc) is a natural plant antioxidant, and epithelioma papulosum cyprini (EPC) cells are a model cell to study carps. Therefore, we conducted experiments with Cd or/and Lyc treatments to investigate the mechanisms of Lyc alleviating Cd-cytotoxicity on EPC cells from the perspectives of miR-375, OS, ACD, and GLU uptake ability. We found that Lyc mitigated Cd-caused miR-375 increase, OS, ACD, and GLU uptake ability reduction. Moreover, miR-375 overexpression/knockdown experiments demonstrated that miR-375 mediated OS, ACD, and GLU uptake ability reduction and targeted regulated IRS1-PI3K-AKT. Furthermore, NAC intervention experiment demonstrated that ROS mediated ACD and the reduction of GLU uptake via ROS/IRS1-PI3K-AKT. Taken together, Lyc alleviated Cd-decreased GLU uptake ability via miR-375-ROS/IRS1-PI3K-AKT and miR-375/IRS1-PI3K-AKT pathways in EPC cells. Our findings highlighted significant role of miR-375 in Cd-induced toxicity and elucidated the mechanism by which Lyc alleviated Cd-induced toxicity. Our study can provide new information and new targets for resisting environmental pollutant stress in animals.

Mitophagy in Alzheimer's disease and other metabolic disorders: A focus on mitochondrial-targeted therapeutics

Mitochondria, as central regulators of cellular processes such as energy production, apoptosis, and metabolic homeostasis, are essential to cellular function and health. The maintenance of mitochondrial integrity, especially through mitophagy-the selective removal of impaired mitochondria-is crucial for cellular homeostasis. Dysregulation of mitochondrial function, dynamics, and biogenesis is linked to neurodegenerative and metabolic diseases, notably Alzheimer's disease (AD), which is increasingly recognized as a metabolic disorder due to its shared pathophysiologic features: insulin resistance, oxidative stress, and chronic inflammation. In this review, we highlight recent advancements in pharmacological interventions, focusing on agents that modulate mitophagy, mitochondrial uncouplers that reduce oxidative phosphorylation, compounds that directly scavenge reactive oxygen species to alleviate oxidative stress, and molecules that ameliorate amyloid beta plaque accumulation and phosphorylated tau pathology. Additionally, we explore dietary and lifestyle interventions-MIND and ketogenic diets, caloric restriction, physical activity, hormone modulation, and stress management-that complement pharmacological approaches and support mitochondrial health. Our review underscores mitochondria's central role in the pathogenesis and potential treatment of neurodegenerative and metabolic diseases, particularly AD. By advocating for an integrated therapeutic model that combines pharmacological and lifestyle interventions, we propose a comprehensive approach aimed at mitigating mitochondrial dysfunction and improving clinical outcomes in these complex, interrelated diseases.

Serine metabolism in aging and age-related diseases

Non-essential amino acids are often overlooked in biomedical research; however, they are crucial components of organismal metabolism. One such metabolite that is integral to physiological function is serine. Serine acts as a pivotal link connecting glycolysis with one-carbon and lipid metabolism, as well as with pyruvate and glutathione syntheses. Interestingly, increasing evidence suggests that serine metabolism may impact the aging process, and supplementation with serine may confer benefits in safeguarding against aging and age-related disorders. This review synthesizes recent insights into the regulation of serine metabolism during aging and its potential to promote healthy lifespan and mitigate a spectrum of age-related diseases.

Therapeutic Potential of N-acetylcysteine and Glycine in Reducing Pulmonary Injury in Diabetic Rats

INTRODUCTION

Diabetes mellitus is associated with systemic complications, including the development of pulmonary injury, characterized mainly by excessive accumulation of extracellular matrix components and inflammatory cell infiltration in lung tissue. This process is driven by oxidative stress and chronic inflammation, both caused and exacerbated by hyperglycemia. N-acetylcysteine (NAC) and glycine, known for their antioxidant and anti-inflammatory effects, offer potential therapeutic benefits in mitigating diabetes-induced lung injury.

OBJECTIVE

The study aimed to investigate the effects of supplementation by either NAC or glycine or their combination on reducing lung injury in rats with type 1 diabetes Materials and methods: The study used 30 adult Wistar albino rats (10 weeks old, weighing between 180 g and 380 g). Six of them were used as controls, while 24 adult rats (10 weeks old, 180-380 g) with type 1 diabetes, induced through a single intraperitoneal injection of streptozotocin (STZ) at a dose of 55 mg/kg, were randomly assigned to four experimental groups: control (CTL), diabetic (Db), NAC treatment (diabetic+NAC), glycine treatment (diabetic+glycine), and combined NAC and glycine treatment (diabetic+NAC+glycine). NAC (100 mg/kg) and glycine (250 mg/kg) were administered orally for 12 weeks. At the end of the study, lung tissues were collected for histopathological examination. Qualitative, semi-quantitative, and stereological histological analysis was used to analyze structural changes in the lung tissue. Semi-quantitative scoring was carried out to evaluate the extent of inflammation, while stereological analysis was performed to determine the volume density of alveolar spaces and septal connective tissue. The semi-quantitative scoring included scores ranging from 0 (absent), 1 (minimal), 2 (mild), 3 (moderate), to 4 (severe).

RESULTS

Qualitative histological analysis revealed pronounced inflammation and fibrosis in the lungs of untreated diabetic rats, characterized by thickened alveolar septa and immune cell infiltration. Both treatments with NAC and glycine individually reduced inflammation and fibrosis compared to untreated diabetic rats. The greatest improvement was observed in the NAC+glycine group, where the alveolar structure appeared almost normal, with minimal inflammation. Semiquantitative analysis showed statistically significant differences in peribronchial and peribrochiolar infiltrates between the diabetic group (2.16±0.47) and the control group (0.33±0.21, p=0.026). The combination of NAC and glycine significantly reduced peribronchial and peribronchiolar infiltrates (0.33±0.33, p=0.026) compared to the diabetic group. Similarly, septal inflammatory infiltrates were significantly lower in the NAC+glycine group (1±0.36) compared to diabetic rats (3.33±0.33, p=0.004). Total airway inflammatory infiltration was also significantly reduced in the NAC+glycine group (1.33±0.33, p=0.002) compared to the diabetic group (5.5±0.5).

CONCLUSION

As the combination of NAC and glycine demonstrated protective effects against lung inflammation and fibrosis in diabetic rats, a synergistic effect of NAC and glycine in mitigating pulmonary complications associated with type 1 diabetes may be suggested. These findings warrant further exploration of the combination for managing diabetic lung disease and potentially other fibrotic conditions.

Enhancing healthy aging with small molecules: A mitochondrial perspective

The pursuit of enhanced health during aging has prompted the exploration of various strategies focused on reducing the decline associated with the aging process. A key area of this exploration is the management of mitochondrial dysfunction, a notable characteristic of aging. This review sheds light on the crucial role that small molecules play in augmenting healthy aging, particularly through influencing mitochondrial functions. Mitochondrial oxidative damage, a significant aspect of aging, can potentially be lessened through interventions such as coenzyme Q10, alpha-lipoic acid, and a variety of antioxidants. Additionally, this review discusses approaches for enhancing mitochondrial proteostasis, emphasizing the importance of mitochondrial unfolded protein response inducers like doxycycline, and agents that affect mitophagy, such as urolithin A, spermidine, trehalose, and taurine, which are vital for sustaining protein quality control. Of equal importance are methods for modulating mitochondrial energy production, which involve nicotinamide adenine dinucleotide boosters, adenosine 5'-monophosphate-activated protein kinase activators, and compounds like metformin and mitochondria-targeted tamoxifen that enhance metabolic function. Furthermore, the review delves into emerging strategies that encourage mitochondrial biogenesis. Together, these interventions present a promising avenue for addressing age-related mitochondrial degradation, thereby setting the stage for the development of innovative treatment approaches to meet this extensive challenge.

The Effect of Glycine and N-Acetylcysteine on Oxidative Stress in the Spinal Cord and Skeletal Muscle After Spinal Cord Injury

Oxidative stress is a frequently occurring pathophysiological feature of spinal cord injury (SCI) and can result in secondary injury to the spinal cord and skeletal muscle atrophy. Studies have reported that glycine and N-acetylcysteine (GlyNAC) have anti-aging and anti-oxidative stress properties; however, to date, no study has assessed the effect of GlyNAC in the treatment of SCI. In the present work, we established a rat model of SCI and then administered GlyNAC to the animals by gavage at a dose of 200 mg/kg for four consecutive weeks. The BBB scores of the rats were significantly elevated from the first to the eighth week after GlyNAC intervention, suggesting that GlyNAC promoted the recovery of motor function; it also promoted the significant recovery of body weight of the rats. Meanwhile, the 4-week heat pain results also suggested that GlyNAC intervention could promote the recovery of sensory function in rats to some extent. Additionally, after 4 weeks, the levels of glutathione and superoxide dismutase in spinal cord tissues were significantly elevated, whereas that of malondialdehyde was significantly decreased in GlyNAC-treated animals. The gastrocnemius wet weight ratio and total antioxidant capacity were also significantly increased. After 8 weeks, the malondialdehyde level had decreased significantly in spinal cord tissue, while reactive oxygen species accumulation in skeletal muscle had decreased. These findings suggested that GlyNAC can protect spinal cord tissue, delay skeletal muscle atrophy, and promote functional recovery in rats after SCI.

Senolytics prevent age-associated changes in female mice brain

PURPOSE

Considering that the combination of dasatinib and quercetin (D + Q) demonstrated a neuroprotective action, as well as that females experience a decline in hormonal levels during aging and this is linked to increased susceptibility to Alzheimer's disease, in this study we evaluated the effect of D + Q on inflammatory and oxidative stress markers and on acetylcholinesterase and Na+, K+-ATPase activities in brain of female mice.

METHODS

Female C57BL/6 mice were divided in Control and D (5 mg/kg) + Q (50 mg/kg) treated. Treatment was administered via gavage for three consecutive days every two weeks starting at 30 days of age. The animals were euthanized at 6 months of age and at 14 months of age.

RESULTS

Results indicate an increase in reactive species (RS), thiol content and lipid peroxidation followed by a reduction in nitrite levels and superoxide dismutase, catalase and glutathione S-transferase activity in the brain of control animals with age. D+Q protected against age-associated increase in RS and catalase activity reduction. Acetylcholinesterase activity was increased, while Na+, K+-ATPase activity was reduced at 14 months of age and D+Q prevented this reduction.

CONCLUSION

These data demonstrate that D+Q can protect against age-associated neurochemical alterations in the female brain.

Dajianzhong decoction ameliorated D-gal-induced cognitive aging by triggering mitophagy in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Dajianzhong decoction (DJZ) is a classical famous formula for treating yang-deficiency-syndrome in traditional Chinese medicine and recorded in Jin-Kui-Yao-Lue in Dynasty of Dong Han. Cognitive aging can present similar features of mitochondrial energy deficits to the clinical features of Yang deficiency. However, there is poor understanding of the effects of DJZ treatment on mitophagy in cognitive aging.

AIM OF THE STUDY

The aims of this work were to decipher the effectiveness and mechanism of DJZ against cognitive aging, focusing on mitophagy.

MATERIALS AND METHODS

YFP-Parkin HeLa cells, D-galactose (D-gal) -induced mice (500 mg/kg for 35 d, s. c.) and SH-SY5Y cells (80 mg/ml for 6 h) were established. Firstly, the formation of YFP-Parkin puncta (a well-known mitophagy marker) in YFP-Parkin HeLa cells was employed to discover the mitophagy induction of DJZ. Moreover, the genes and proteins related to PINK1/Parkin pathway and mitochondrial functions were evaluated after treatment with DJZ in vivo (3.5 g/kg or 1.75 g/kg, i. g, 35 d) and in vitro (0.2, 2 and 20 μg/ml, 12 h). Furthermore, the effectiveness of DJZ (3.5 g/kg or 1.75 g/kg, i. g) for alleviating cognitive aging and nerve damage was measured in D-gal mice. Finally, siPINK1 was applied to reverse validation of DJZ in vitro.

RESULTS

The formation of YFP-Parkin puncta in YFP-Parkin HeLa cells was markedly induced by DJZ in a dose-dependent manner. The immunofluorescence intensity of Parkin and the protein expression of Parkin in mitochondrial membrane in D-gal mice were significantly increased after treatment of DJZ. The inhibition of PINK1/Parkin pathway in D-gal-induced mice and SH-SY5Y cells was significantly activated by DJZ. Simultaneously, the impairment of mitochondrial functions induced by D-gal were markedly reversed by DJZ. In addition, DJZ significantly ameliorated the neuropathological injury and cognitive declines in D-gal mice. Finally, after PINK1 was knocked down by siPINK1 in vitro, the neuroprotective effects of DJZ and the Parkin enhancement effect of DJZ were markedly reversed.

CONCLUSION

Our findings firstly showed DJZ could relieve cognitive aging through facilitating PINK1/Parkin-mediated mitophagy to protect against mitochondrial functions, indicating DJZ may be regarded as a promising intervention in cognitive aging.