Resveratrol ameliorates thymus senescence changes in D-galactose induced mice

LncRNA NEAT1-206 regulates autophagy of human umbilical cord mesenchymal stem cells through the WNT5A/Ca2+ signaling pathway under senescence stress

Stem cells are crucial for maintaining bodily stability, but their regenerative abilities decline with age. This decline is marked by reduced proliferation and differentiation capacities of stem cells, as well as exhaustion of the stem cell pool. The accumulation of aged mesenchymal stem cells (MSCs) can reduce the tissue regeneration, but the molecular mechanisms influencing MSCs aging remain unclear. Moreover, collecting MSCs from elderly individuals is not suitable for observing the early response of MSCs to senescence stress, and the factors involved in early senescence remain unclear. In our previous study, we established a fast MSC aging model using D-galactose. We discovered that, while not affecting the "stemness" markers of mesenchymal stem cells, the expression of LncRNA NEAT1-206 was notably increased during the early stages of aging induction (within 4 days). And LncRNA NEAT1-206 was observed to be localized in the cytoplasmic matrix due to enhanced nuclear export. We found that the LncRNA NEAT1-206 could trigger autophagy through the WNT5A/Ca2+ signaling pathway, thereby decreasing senescence markers and enhancing the osteogenic differentiation of MSCs. This study elucidated the role that LncRNA NEAT1-206 as a potential key factor in conferring resistance to D-galactose-induced cell senescence at the early stage and promoting the osteogenic differentiation of MSCs. This study may provide a foundational understanding for delaying the MSCs aging process.

Syringic acid improves cyclophosphamide-induced immunosuppression in a mouse model

Syringic acid (SA), a naturally occurring phenolic substance present in many edible plants and fruits, has been shown to have potential in immunoenhancement applications. In this study, we investigated the immunomodulatory effects of SA in mitigating cyclophosphamide (CYP)-induced immunosuppression in BALB/c mice using doxycycline as a positive control. SA administration prevented immune organ atrophy and morphological changes in the thymus, spleen, and bone marrow induced by CYP treatment in mice while also showing a dose-dependent enhancement of thymus and spleen indices compared to mice treated with CYP alone. Furthermore, SA improved thymocyte and splenocyte proliferation and exhibited significant antioxidant activity by reducing the elevated levels of malondialdehyde induced by CYP treatment. SA treatment effectively restored white blood cell (WBC) and lymphocyte counts to normal levels in CYP-treated animals, and the protective effects of CYP on immunological tissues were confirmed through histopathological examination. Moreover, SA treatment upregulated the expression of IL-6, IL-7, IL-15, and FoxN1. Finally, molecular docking studies revealed that binding energy values predicted minor inhibition potential toward IL-6, IL-7, FoxN1, IL-15, STAT3, STAT5, and JAK3. Overall, our findings suggest that SA treatment has the potential to reduce CYP-induced immunosuppression and may have applications as an immunologic adjuvant or functional food additive in chemotherapy.

The effect of plant-derived polyphenols on the immune system during aging: a systematic review

OBJECTIVE

Polyphenols are organic compounds with diverse biological activities such as anti-inflammatory and antioxidant effects, making them important candidates for the development of anti-aging drugs. In this systematic review, we aimed to answer the question: can plant-derived polyphenols have an immunomodulatory effect in experimental models of aging?

METHODS

We systematically searched Web of Science, MEDLINE/Pubmed, and Embase to select articles using the following combinations of terms and synonyms: polyphenols, phenols, senescence, aging, and immune. The selected articles were evaluated for reporting quality and risk-of-bias according to standard guidelines.

RESULTS

The most used polyphenol was resveratrol, followed by curcumin, salidroside, and gallic acid. These molecules demonstrated an ability to restore immune function both in vitro and in vivo. The mechanism of action was not completely elucidated in these studies, but inhibition of NF-kB signaling, and antioxidant properties seemed to account for the anti-aging effects. All articles included in the review had good quality of reporting but failed to describe an adequate sample size, criteria for inclusion/exclusion, randomization, and blinding.

CONCLUSION

We conclude that polyphenols are promising immunomodulatory substances for use in anti-aging therapies. However, more research with standardized analysis is needed to understand the role of these molecules in the prevention or reduction of damage associated with the aging process, as well as to determine the safety profile and consequences of systemic action.

Botanical Bioflavonoid Composition from Scutellaria baicalensis- and Acacia catechu-Protected Mice against D-Galactose-Induced Immunosenescence, and Cyclophosphamide Induced Immune Suppression

Oxidative stress and chronic inflammation create a perpetual cycle in the elderly, where impaired immune function amplifies susceptibility to oxidative damage, and oxidative stress further weakens the immune response. This cycle is particularly detrimental to the respiratory system of the elderly, which is an easy target for constant exogenous harmful attacks during cold/flu season or under heavy air pollution. Herbal medicines that protect respiratory function are seen as safer alternatives to conventional therapies; however, there is limited availability of scientifically validated, safe, and effective natural supplements for these conditions. In this study, we evaluated a standardized bioflavonoid composition, UP446, that contains bioactives from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu as a natural and nutritional supplement for its antioxidative and immunoregulatory effects in oxidative stress-accelerated aging and chemically induced immune suppression mouse models. Immunosenescence was induced through the repeated subcutaneous inoculation of D-galactose (D-Gal) at a dose of 500 mg/kg/day in CD-1 mice. UP446 was administered orally at doses of 100 mg/kg and 200 mg/kg starting in the fifth week of immunosenescence induction. This study lasted a total of ten weeks. All mice received a quadrivalent influenza vaccine 2 weeks before termination. Whole blood, serum, spleen homogenate, and thymus tissues were processed for analysis. Cyclophosphamide (Cy)-induced immunosuppression was triggered by three consecutive injections of cyclophosphamide at 80 mg/kg/day, followed by the oral administration of UP446 for 18 days at doses of 100 mg/kg and 200 mg/kg. Blood was collected from each animal at necropsy, and serum was isolated for IgA and IgG ELISA analysis. UP446 was found to improve immune response, as evidenced by the stimulation of innate (NK cells) and adaptive immune responses (T cells and cytotoxic T cells), an increase in antioxidant capacity (glutathione peroxidase), the preservation of vital immune organs (the thymus), and a reduction in NFκB. UP446 also increased serum levels of IgA and IgG. The findings presented in this report demonstrate the antioxidative, anti-inflammatory, and immune-regulatory activities of UP446, suggesting its potential use in respiratory conditions involving immune stress due to aging, oxidative stress, and/or pathogenic challenges.

An Aloe-Based Composition Constituting Polysaccharides and Polyphenols Protected Mice against D-Galactose-Induced Immunosenescence

A decline in immune response, exhibited in the form of immunosenescence and inflammaging, is an age-associated disturbance of the immune system known to predispose the elderly to a greater susceptibility to infection and poor vaccine response. Polysaccharides and polyphenols from botanicals are known for their immune modulation effects. Here we evaluated a standardized mushroom-based composition, UP360, from Aloe barbadensis, Poria cocos, and Rosmarinus officinalis, as a natural nutritional supplement for a balanced immune response in an accelerated aging mouse model. Immunosenescence was induced by continual subcutaneous injection of D-galactose (D-gal) at a dose of 500 mg/kg/day to CD-1 mice. UP360 was administered at oral doses of 200 and 400 mg/kg to the mice starting on the 5th week of D-gal injection. The study lasted for a total of 9 weeks. All mice were given a quadrivalent influenza vaccine at 3 µg/animal via intramuscular injection 14 days before the end of the study. A group of D-gal-treated mice treated at 400 mg/kg/day UP360 was kept without vaccination. Whole blood, serum, spleen homogenate, and thymus tissues were used for analysis. UP360 was found to improve the immune response as evidenced by stimulation of innate and adaptive immune responses, increase antioxidant capacity as reflected by augmented SOD and Nrf2, and preserve vital immune organs, such as the thymus, from aging-associated damage. The findings depicted in this report show the effect of the composition in activating and maintaining homeostasis of the immune system both during active infections and as a preventive measure to help prime the immune system. These data warrant further clinical study to explore the potential application of the mushroom-based composition as an adjunct nutritional supplement for a balanced immune response.

Epithelial-mesenchymal transition in age-associated thymic involution: Mechanisms and therapeutic implications

The thymus is a critical immune organ with endocrine and immune functions that plays important roles in the physiological and pathological processes of the body. However, with aging, the thymus undergoes degenerative changes leading to decreased production and output of naive T cells and the secretion of thymic hormones and related cytokines, thereby promoting the occurrence and development of various age-associated diseases. Therefore, identifying essential processes that regulate age-associated thymic involution is crucial for long-term control of thymic involution and age-associated disease progression. Epithelial-mesenchymal transition (EMT) is a well-established process involved in organ aging and functional impairment through tissue fibrosis in several organs, such as the heart and kidney. In the thymus, EMT promotes fibrosis and potentially adipogenesis, leading to thymic involution. This review focuses on the factors involved in thymic involution, including oxidative stress, inflammation, and hormones, from the perspective of EMT. Furthermore, current interventions for reversing age-associated thymic involution by targeting EMT-associated processes are summarized. Understanding the key mechanisms of thymic involution through EMT as an entry point may promote the development of new therapies and clinical agents to reverse thymic involution and age-associated disease.

Thymus aging and immune reconstitution, progresses and challenges

Thymus is a primary lymphoid organ essential for the development of T lymphocytes. Age-related thymic involution is a prominent feature of immune senescence. The thymus undergoes rapid growth during fetal and neonatal development, peaks in size before puberty and then begins to undergo a decrease in cellularity with age. Dramatic changes occur with age-associated thymic involution. The most prominent features of thymic involution include: (i) epithelial structure disruption, (ii) adipogenesis, and (iii) thymocyte development arrest. There is a sex disparity in thymus aging. It is a multifactorial process controlled and regulated by a series of molecules, including the transcription factor FOXN1, fibroblast and keratinocyte growth factors (FGF and KGF, respectively), sex steroids, Notch signaling, WNT signaling, and microRNAs. Nevertheless, there is still no satisfactory evolutionary or physiological explanation for age-associated thymic involution, and understanding the precise mechanism(s) for thymus aging remains challenging. Sustained thymic regeneration has yet to be achieved by sex steroid ablation. Recent preclinical studies indicate that long-term thymic reconstitution can be achieved via adoptive transfer of in vitro-generated progenitor T (proT) cells, and improvements in the methods for the generation of human proT cells make this an attractive approach. Future clinical applications may rely on new applications integrating proT cells, cytokine support and sex-steroid inhibition treatments.

Development of the Thymus and Kidney and Effects of Resveratrol on Their Aging in a Short-Lived Fish

Annual fishes of the genus Nothobranchius have been widely used in cognitive, behavioral, and genetic studies, and have become an excellent animal model for studying aging. However, the development and degeneration of immune organs in annual fishes and the antagonistic effects of resveratrol remain unclear. In the present study, the development of thymus and kidney was investigated systematically using Nothobranchius guentheri from larvae, juveniles, and young and old fish with hematoxylin and eosin staining. We found that thymus primordium was observed first in the larvae at 2 days after hatching (dah). After the lymphoid cells became evident at 5 dah, the thymus acquired an irregular shape at 7 dah. Then it formed a wedge shape at 15 dah. Thymus looked as homogeneous distribution of lymphocytes at 1 month old, and it differentiated into cortex and medulla approximately in 2-month-old fish. Combined with TUNEL and senescence-associated β-galactosidase (SA-β-gal) staining, it showed the degeneration of the thymus appeared in 4-month-old fish. Kidney primordium appeared on 1 dah, and the glomerulus was visible at 7 dah. The nephrogenic activity was most apparent in 1-month-old fish. A large hematopoietic tissue was arranged in the renal interstitium in 2- and 3-month-old fish. In 6-month-old fish, the kidney structure became less dense. By 12 months, the kidney exhibited the most pronounced histological characteristics of aging. Feeding resveratrol ameliorated renal fibrosis and SA-β-gal staining with age, increased SIRT1 and SIRT3 expression, and decreased the levels of NF-κB and inflammatory factors in thymus and kidney of the fish. We provided basic data for the development and degeneration of immune organs and resveratrol's anti-aging effects in short-lived fish.

Resveratrol Reverses Endothelial Colony-Forming Cell Dysfunction in Adulthood in a Rat Model of Intrauterine Growth Restriction

Individuals born after intrauterine growth restriction (IUGR) are at risk of developing cardiovascular diseases (CVDs). Endothelial dysfunction plays a role in the pathogenesis of CVDs; and endothelial colony-forming cells (ECFCs) have been identified as key factors in endothelial repair. In a rat model of IUGR induced by a maternal low-protein diet, we observed an altered functionality of ECFCs in 6-month-old males, which was associated with arterial hypertension related to oxidative stress and stress-induced premature senescence (SIPS). Resveratrol (R), a polyphenol compound, was found to improve cardiovascular function. In this study, we investigated whether resveratrol could reverse ECFC dysfunctions in the IUGR group. ECFCs were isolated from IUGR and control (CTRL) males and were treated with R (1 μM) or dimethylsulfoxide (DMSO) for 48 h. In the IUGR-ECFCs, R increased proliferation (5'-bromo-2'-deoxyuridine (BrdU) incorporation, p < 0.001) and improved capillary-like outgrowth sprout formation (in Matrigel), nitric oxide (NO) production (fluorescent dye, p < 0.01), and endothelial nitric oxide synthase (eNOS) expression (immunofluorescence, p < 0.001). In addition, R decreased oxidative stress with reduced superoxide anion production (fluorescent dye, p < 0.001); increased Cu/Zn superoxide dismutase expression (Western blot, p < 0.05); and reversed SIPS with decreased beta-galactosidase activity (p < 0.001), and decreased p16^ink4a (p < 0.05) and increased Sirtuin-1 (p < 0.05) expressions (Western blot). No effects of R were observed in the CTRL-ECFCs. These results suggest that R reverses long-term ECFC dysfunctions related to IUGR.

Metformin ameliorates thymus degeneration of mice by regulating mitochondrial function

As the main lymphoid organ, the thymus degenerates with age. The loss of thymic epithelial cells is mainly related to thymus degeneration and reduced T cells development. As an insulin sensitizer, metformin is a first-line drug for the treatment of diabetes and has been shown to prolong the lifespan of mice, but the mechanism is still unclear. In this study, we explored the therapeutic effect of metformin on thymus degeneration in the accelerated aging mice, which was established by intraperitoneal injection D-galactose (120 mg/kg/day) for eight weeks. Metformin was intragastrically given with 100 or 300 mg/kg body weight per day, respectively, for six weeks. Histological examination showed that metformin administration could alleviate thymus atrophy caused by D-galactose. In addition, metformin therapy increased mitochondrial membrane potential, with a reduction in mitochondrial reactive oxygen species, MDA and SOD levels, and restored mitochondrial balance through enhanced expression of dynamin-related protein 1 (Drp1). Furthermore, metformin altered T lymphocyte subsets and cellular senescent cells; the expression of FoxN1, Aire and Sox2 of thymic epithelial cells also increased. Thus, metformin presented a positive effect on thymic degeneration through improving mitochondrial function. Taken together, these findings revealed an unexpected complexity in the anti-aging of this widely used drug.

Dosage effects of resveratrol on thymus involution in D-galactose-treated mice

The thymus regulates a specific microenvironment for the growth and maturation of naive T cells. Involution of immune function was an important factor during body aging. Preventing the senescence of immune organs has become a major medical issue. Resveratrol (RSV) has been proved to delay the aging of many organs including the thymus. However, the underlying mechanism remains indefinite and the dosages of RSV on thymus involution need to be further clarified. In the current study, the senescence-accelerated mice were produced using d-galactose for two months. RSV at different dosages (25, 50, 100 mg kg^-1  day^-1 ) was then administered. The alteration of the thymic morphological structure was observed. It showed that three dosages of RSV significantly decreased cellular senescence of the thymus and no dosage difference was detected. For cellular proliferation and apoptosis of the thymus, 50 and 25 mg/kg per day of RSV displayed the best effects on cellular proliferation and apoptosis in the thymus, respectively. Furthermore, 50 mg/kg per day of RSV increased the expression of FoxN1 both at transcription and translation levels. These findings indicated that RSV could delay thymus atrophy in a dosage-dependent pattern and FoxN1 might involve in the beneficial mechanism of RSV, which was of great significance for the enhancement of thymic health and organic immunity. PRACTICAL APPLICATIONS: Resveratrol has been proved to delay aging of many organs including of thymus. In the present study, we explored the dosage of resveratrol on thymus involution and the expression of transcription factors forkhead box protein N1 (FoxN1) in the senescenceaccelerated mice induced by D-galactose. The results indicated that resveratrol could delay thymus atrophy in a dosage-dependent pattern within a certain dose range, and higher RSV concentration may have drug toxicity, which suggests that the dosage of RSV requires attention, And FoxN1 might involve in the beneficial mechanism of resveratrol supplement, which was of great significance to explore the mechanism for the enhancement of thymus immunity.