Role of mitochondrial homeostasis in D-galactose-induced cardiovascular ageing from bench to bedside

Ageing is an inevitable phenomenon which affects the cellular to the organism level in the progression of the time. Oxidative stress and inflammation are now widely regarded as the key processes involved in the aging process, which may then cause significant harm to mitochondrial DNA, leading to apoptosis. Normal circulatory function is a significant predictor of disease-free life expectancy. Indeed, disorders affecting the cardiovascular system, which are becoming more common, are the primary cause of worldwide morbidity, disability, and mortality. Cardiovascular aging may precede or possibly underpin overall, age-related health decline. Numerous studies have foundmitochondrial mechanistc approachplays a vital role in the in the onset and development of aging. The D-galactose (D-gal)-induced aging model is well recognized and commonly used in the aging study. In this review we redeposit the association of the previous and current studies on mitochondrial homeostasis and its underlying mechanisms in D-galactose cardiovascular ageing. Further we focus the novel and the treatment strategies to combat the major complication leading to the cardiovascular ageing.

Saponins from Panax japonicus improve neuronal mitochondrial injury of aging rats

CONTEXT

Panax japonicus is the dried rhizome of Panax japonicus C.A. Mey. (Araliaceae). Saponins from Panax japonicus (SPJ) exhibit anti-oxidative and anti-aging effects.

OBJECTIVE

We evaluated the neuroprotective effects of SPJ on aging rats.

MATERIALS AND METHODS

Sprague-Dawley rats (18-months-old) were randomly divided into aging and SPJ groups (n = 8). Five-month-old rats were taken as the adult control (n = 8). The rats were fed a normal chow diet or the SPJ-containing diet (10 or 30 mg/kg) for 4 months. An in vitro model was established by d-galactose (d-Gal) in the SH-SY5Y cell line and pretreated with SPJ (25 and 50 µg/mL). The neuroprotection of SPJ was evaluated via Nissl staining, flow cytometry, transmission electron microscopy and Western blotting in vivo and in vitro.

RESULTS

SPJ improved the neuronal degeneration and mitochondrial morphology that are associated with aging. Meanwhile, SPJ up-regulated the protein levels of mitofusin 2 (Mfn2) and optic atrophy 1 (Opa1) and down-regulated the protein level of dynamin-like protein 1 (Drp1) in the hippocampus of aging rats (p < 0.05 or p < 0.01 vs. 22 M). The in vitro studies also demonstrated that SPJ attenuated d-Gal-induced cell senescence concomitant with the improvement in mitochondrial function; SPJ, also up-regulated the Mfn2 and Opa1 protein levels, whereas the Drp1 protein level (p < 0.05 or p < 0.01 vs. d-Gal group) was down-regulated.

DISCUSSION AND CONCLUSIONS

Further research on the elderly population will contribute to the development and utilization of SPJ for the treatment of neurodegenerative disorders.

Bioactive Peptides from Edible Mushrooms-The Preparation, Mechanisms, Structure-Activity Relationships and Prospects

Mushroom bioactive peptides (MBPs) are bioactive peptides extracted directly or indirectly from edible mushrooms. MBPs are known to have antioxidant, anti-aging, antibacterial, anti-inflammatory and anti-hypertensive properties, and facilitate memory and cognitive improvement, antitumour and anti-diabetes activities, and cholesterol reduction. MBPs exert antioxidant and anti-inflammatory effects by regulating the MAPK, Keap1-Nrf2-ARE, NF-κB and TNF pathways. In addition, MBPs exert antibacterial, anti-tumour and anti-inflammatory effects by stimulating the proliferation of macrophages. The bioactivities of MBPs are closely related to their molecular weights, charge, amino acid compositions and amino acid sequences. Compared with animal-derived peptides, MBPs are ideal raw materials for healthy and functional products with the advantages of their abundance of resources, safety, low price, and easy-to-achieve large-scale production of valuable nutrients for health maintenance and disease prevention. In this review, the preparation, bioactivities, mechanisms and structure-activity relationships of MBPs were described. The main challenges and prospects of their application in functional products were also discussed. This review aimed to provide a comprehensive perspective of MBPs.

Lysyl oxidase-like 2 inhibitor rescues D-galactose-induced skeletal muscle fibrosis

Aging-related sarcopenia is currently the most common sarcopenia. The main manifestations are skeletal muscle atrophy, replacement of muscle fibers with fat and fibrous tissue. Excessive fibrosis can impair muscle regeneration and function. Lysyl oxidase-like 2 (LOXL2) has previously been reported to be involved in the development of various tissue fibrosis. Here, we investigated the effects of LOXL2 inhibitor on D-galactose (D-gal)-induced skeletal muscle fibroblast cells and mice. Our molecular and physiological studies show that treatment with LOXL2 inhibitor can alleviate senescence, fibrosis, and increased production of reactive oxygen species in fibroblasts caused by D-gal. These effects are related to the inhibition of the TGF-β1/p38 MAPK pathway. Furthermore, in vivo, mice treatment with LOXL2 inhibitor reduced D-gal-induced skeletal muscle fibrosis, partially enhanced skeletal muscle mass and strength and reduced redox balance disorder. Taken together, these data indicate the possibility of using LOXL2 inhibitors to prevent aging-related sarcopenia, especially with significant fibrosis.

The regulatory effect of total flavonoids of Sedum aizoon L. on oxidative stress in type 1 diabetic mice

In this study, the optimal extraction conditions for the total flavonoids of Sedum aizoon L. (STF) were optimized by response surface methodology. Evaluation of the antioxidant in vitro of STF, and modulatory effects of glucolipid metabolism, and oxidative stress in mice with type 1 diabetes mellitus (T1DM). STF showed good antioxidant capacity in vitro. STF could improve glucolipid metabolism, organ coefficients, and antioxidant stress enzymes in T1DM mice effectively, reduce the damage to liver tissue, and regulate redox imbalance in the organism by modulating the Nrf2/Keap1/ARE signaling pathway. The results of this study could provide a theoretical reference for the application of Sedum aizoon L. in the development of auxiliary hypoglycemic functional foods and improvement of diabetes.

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Optimization of optimal extraction conditions by response surface methodology.

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Total flavonoids of Sedum aizoon L. have good antioxidant activity in vitro.

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Total flavonoids of Sedum aizoon L. have hypoglycemic effect.

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Total flavonoids of Sedum aizoon L. can improve the oxidative stress in T1DM mice.

Phlorizin exerts potent effects against aging induced by D-galactose in mice and PC12 cells

Phlorizin is the main active ingredient of apple peel and has potential utilization value. Some recent studies have suggested that phlorizin may have antioxidant capacity and protect the liver. The injection of a low dose of d-galactose can cause some changes that resemble accelerated aging in mice. This study explored the protective effects of phlorizin on d-galactose-induced mice and PC12 cells. In this study, ICR mice were divided into a normal group (NOR), a d-galactose model group (d-gal) and phlorizin treatment groups (100 mg kg-1, 200 mg kg-1 and 400 mg kg-1). In addition to the NOR group, four other groups were injected with d-galactose (120 mg kg-1) for 12 weeks. The results showed that phlorizin reduced the decline of strength, coordination and spatial memory caused by aging, increased the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), increased total antioxidant capacity (T-AOC), and reduced the content of malondialdehyde (MDA). On the other hand, phlorizin increased the levels of interleukin-2 (IL-2) and acetylcholine (ACh), reduced the release of interleukin-6 (IL-6), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and decreased the activity of acetylcholinesterase (AChE) in the brain, improved the expression of antioxidant genes related to the nuclear factor E2-related factor 2 (Nrf2) pathway, and reduced the occurrence of morphological lesions in the hippocampus and liver. In addition, phlorizin improved cell viability and reduced the cytotoxicity of d-galactose-induced oxidative stress in PC12 cells. Meanwhile, the protective effect of phlorizin was abolished in Nrf2 gene knockdown PC12 cells. Furthermore, molecular docking showed that phlorizin could bind Keap1 protein, which can interact with Nrf2 protein. Therefore, these results suggest that phlorizin may delay senescence and enhance antioxidant capacity through the Nrf2 pathway.

Astaxanthin attenuates d-galactose-induced brain aging in rats by ameliorating oxidative stress, mitochondrial dysfunction, and regulating metabolic markers

Astaxanthin (AX) is a red-colored xanthophyll carotenoid with potent antioxidant, anti-inflammatory, and neuroprotective properties. However, the underlying in vivo mechanism by which AX protects the brain from oxidative stress remains unclear. In this study, we investigated the protective effect of AX on brain oxidative damage in a d-galactose-induced rat model of aging. We also explored its possible mechanism of action by analyzing the resulting serum metabolic profiles. Our results showed that AX significantly increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) by 26%, 30%, and 53%, respectively. AX also significantly increased the mitochondrial membrane potential by 18% when compared with the model group. Additionally, treatment with AX (15 mg kg^-1) increased the activities of respiratory chain complexes I and IV by 50.17% and 122.87%, respectively. Furthermore, AX also improved age-related morphological changes in the cerebral cortex and hippocampus. Significant differences in serum metabolic profiles were observed between the d-galactose and AX treatment groups. AX corrected amino acid metabolic problems by increasing the levels of N-acetyl-l-leucine, N-acetyl-l-tyrosine, and methionine sulfoxide to protect nerve cells. This also allowed AX to regulate the pentose phosphate pathway by acting on ergotoxine, d-xylose-5-phosphoric, and thiamine, to against oxidative stress and apoptosis. Moreover, AX reduced the levels of both hyodeoxycholic acid and chenodeoxycholic acid though the primary bile acid biosynthesis pathway, resulting in improved brain mitochondrial dysfunction. In conclusion, AX likely enhances the brain's antioxidant defenses through these potential metabolic means, enabling the brain to resist mitochondrial dysfunction, improve neuronal damage, and protect the electron transmission of mitochondrial respiratory chain, thus preventing brain aging.