Growth differentiation factor 11 is a circulating factor that reverses age-related cardiac hypertrophy

A germline-to-soma signal triggers an age-related decline of mitochondrial stress response

The abilities of an organism to cope with extrinsic stresses and activate cellular stress responses decline during aging. The signals that modulate stress responses in aged animals remain to be elucidated. Here, we discover that feeding Caenorhabditis elegans (C. elegans) embryo lysates to adult worms enabled the animals to activate the mitochondrial unfolded protein response (UPRmt) upon mitochondrial perturbations. This discovery led to subsequent investigations that unveil a hedgehog-like signal that is transmitted from the germline to the soma in adults to inhibit UPRmt in somatic tissues. Additionally, we find that the levels of germline-expressed piRNAs in adult animals markedly decreased. This reduction in piRNA levels coincides with the production and secretion of a hedgehog-like signal and suppression of the UPRmt in somatic cells. Building upon existing research, our study further elucidates the intricate mechanisms of germline-to-soma signaling and its role in modulating the trade-offs between reproduction and somatic maintenance within the context of organismal aging.

Muscle aging and sarcopenia: The pathology, etiology, and most promising therapeutic targets

Sarcopenia is a progressive muscle wasting disorder that severely impacts the quality of life of elderly individuals. Although the natural aging process primarily causes sarcopenia, it can develop in response to other conditions. Because muscle function is influenced by numerous changes that occur with age, the etiology of sarcopenia remains unclear. However, recent characterizations of the aging muscle transcriptional landscape, signaling pathway disruptions, fiber and extracellular matrix compositions, systemic metabolomic and inflammatory responses, mitochondrial function, and neurological inputs offer insights and hope for future treatments. This review will discuss age-related changes in healthy muscle and our current understanding of how this can deteriorate into sarcopenia. As our elderly population continues to grow, we must understand sarcopenia and find treatments that allow individuals to maintain independence and dignity throughout an extended lifespan.

Blood-derived factors to brain communication in brain diseases

Brain diseases, mainly including acute brain injuries, neurodegenerative diseases, and mental disorders, have posed a significant threat to human health worldwide. Due to the limited regenerative capability and the existence of the blood-brain barrier, the brain was previously thought to be separated from the rest of the body. Currently, various cross-talks between the central nervous system (CNS) and peripheral organs have been widely described, including the brain-gut axis, the brain-liver axis, the brain-skeletal muscle axis, and the brain-bone axis. Moreover, several lines of evidence indicate that leveraging systemic biology intervention approaches, including but not limited to lifestyle interventions, exercise, diet, blood administration, and peripheral immune responses, have demonstrated a significant influence on the progress and prognosis of brain diseases. The advancement of innovative proteomic and transcriptomic technologies has enriched our understanding of the nuanced interplay between peripheral organs and brain diseases. An array of novel or previously underappreciated blood-derived factors have been identified to play pivotal roles in mediating these communications. In this review, we provide a comprehensive summary of blood-to-brain communication following brain diseases. Special attention is given to the instrumental role of blood-derived signals, positing them as significant contributors to the complex process of brain diseases. The insights presented here aim to bridge the current knowledge gaps and inspire novel therapeutic strategies for brain diseases.

Pathomechanisms of Monoallelic variants in TTN causing skeletal muscle disease

Pathogenic variants in the titin gene (TTN) are known to cause a wide range of cardiac and musculoskeletal disorders, with skeletal myopathy mostly attributed to biallelic variants. We identified monoallelic truncating variants (TTNtv), splice site or internal deletions in TTN in probands with mild, progressive axial and proximal weakness, with dilated cardiomyopathy frequently developing with age. These variants segregated in an autosomal dominant pattern in 7 out of 8 studied families. We investigated the impact of these variants on mRNA, protein levels, and skeletal muscle structure and function. Results reveal that nonsense-mediated decay likely prevents accumulation of harmful truncated protein in skeletal muscle in patients with TTNtvs. Splice variants and an out-of-frame deletion induce aberrant exon skipping, while an in-frame deletion produces shortened titin with intact N- and C-termini, resulting in disrupted sarcomeric structure. All variant types were associated with genome-wide changes in splicing patterns, which represent a hallmark of disease progression. Lastly, RNA-seq studies revealed that GDF11, a member of the TGF-β superfamily, is upregulated in diseased tissue, indicating that it might be a useful therapeutic target in skeletal muscle titinopathies.

Novel insights into the pleiotropic health effects of growth differentiation factor 11 gained from genome-wide association studies in population biobanks

BACKGROUND

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor-β (TGF-β) superfamily that has gained considerable attention over the last decade for its observed ability to reverse age-related deterioration of multiple tissues, including the heart. Yet as many researchers have struggled to confirm the cardioprotective and anti-aging effects of GDF11, the topic has grown increasingly controversial, and the field has reached an impasse. We postulated that a clearer understanding of GDF11 could be gained by investigating its health effects at the population level.

METHODS AND RESULTS

We employed a comprehensive strategy to interrogate results from genome-wide association studies in population Biobanks. Interestingly, phenome-wide association studies (PheWAS) of GDF11 tissue-specific cis-eQTLs revealed associations with asthma, immune function, lung function, and thyroid phenotypes. Furthermore, PheWAS of GDF11 genetic variants confirmed these results, revealing similar associations with asthma, immune function, lung function, and thyroid health. To complement these findings, we mined results from transcriptome-wide association studies, which uncovered associations between predicted tissue-specific GDF11 expression and the same health effects identified from PheWAS analyses.

CONCLUSIONS

In this study, we report novel relationships between GDF11 and disease, namely asthma and hypothyroidism, in contrast to its formerly assumed role as a rejuvenating factor in basic aging and cardiovascular health. We propose that these associations are mediated through the involvement of GDF11 in inflammatory signaling pathways. Taken together, these findings provide new insights into the health effects of GDF11 at the population level and warrant future studies investigating the role of GDF11 in these specific health conditions.

Therapeutic targeting of GDF11 in muscle atrophy: Insights and strategies

The exploration of novel therapeutic avenues for skeletal muscle atrophy is imperative due to its significant health impact. Recent studies have spotlighted growth differentiation factor 11 (GDF11), a TGFβ superfamily member, for its rejuvenating role in reversing age-related tissue dysfunction. This review synthesizes current findings on GDF11, elucidating its distinct biological functions and the ongoing debates regarding its efficacy in muscle homeostasis. By addressing discrepancies in current research outcomes and its ambiguous role due to its homological identity to myostatin, a negative regulator of muscle mass, this review aims to clarify the role of GDF11 in muscle homeostasis and its potential as a therapeutic target for muscle atrophy. Through a thorough examination of GDF11's mechanisms and effects, this review provides insights that could pave the way for innovative treatments for muscle atrophy, emphasizing the need and strategies to boost endogenous GDF11 levels for therapeutic potential.

Hyaluronan and proteoglycan link protein 1 - a novel signaling molecule for rejuvenating aged skin

The skin seems to rejuvenate upon exposure to factors within the circulation of young organisms. Intrinsic factors that modulate skin aging are poorly understood. We used heterochronic parabiosis and aptamer-based proteomics to identify serum-derived rejuvenating factors. We discovered a novel extracellular function of hyaluronan and proteoglycan link protein 1 (HAPLN1). Its serum levels decreased with age, disturbing the integrity of the skin extracellular matrix, which is predominantly composed of collagen I and hyaluronan; levels of various markers, which decrease in aged skin, were significantly restored in vivo and in vitro by the administration of recombinant human HAPLN1 (rhHAPLN1). rhHAPLN1 protected transforming growth factor beta receptor 2 on the cell surface from endocytic degradation via mechanisms such as regulation of viscoelasticity, CD44 clustering, and hyaluronan cross-linking. Moreover, rhHAPLN1 regulated the levels of nuclear factor erythroid 2-related factor 2, phosphorylated nuclear factor kappa B, and some cyclin-dependent kinase inhibitors such as p16 and p21. Therefore, rhHAPLN1 may act as a novel biomechanical signaling protein to rejuvenate aged skin.

Aging insights from heterochronic parabiosis models

Heterochronic parabiosis consists of surgically connecting the circulatory systems of a young and an old animal. This technique serves as a model to study circulating factors that accelerate aging in young organisms exposed to old blood or induce rejuvenation in old organisms exposed to young blood. Despite the promising results, the exact cellular and molecular mechanisms remain unclear, so this study aims to explore and elucidate them in more detail.

The disparity of platelet factor 4 and platelets in individuals of different ages

The aging process profoundly impacts the systemic milieu, with specific blood-borne factors playing critical roles in its regulation. Platelet Factor 4 (PF4), released by platelets, has emerged as a novel blood-borne factor that contributes to the rejuvenation of aging brains in rodents. However, the age-related disparity in PF4 levels in humans remains poorly understood. To explore the relationship between PF4 and the natural aging process in humans, we collected peripheral blood (PB) samples from young (23.40 ± 2.13 years, n = 15) and elderly (75.23 ± 4.19 years, n = 13) individuals, along with cord blood (CB) samples (n = 15). ELISA analysis revealed higher PF4 levels in platelet-rich plasma lysate from young PB compared with that from elderly PB. Consistent with this, qPCR results demonstrated the highest PF4 expression in young PB among the three groups. In addition, FACS analysis showed increased expression of CXCR3 in mononuclear cells of young PB, indicating a greater responsiveness to PF4. Finally, our RNA-sequencing analysis corroborated platelets as a sensitive element during the natural aging process, and indicated platelets play a pivotal role in antioxidant response during aging, as evidenced by significant enrichment of several age-related pathways. These findings reveal that, alongside PF4 levels, platelets undergo substantial alterations during aging. Taken together, our data identified age-related disparities in platelets and PF4-related elements during natural aging and underscored the potential of targeting platelet modulation as an intervention in the aging process.

GDF11 evokes lung injury, inflammation, and fibrosis in mice through the ALK5-Smad2/3 signaling pathway

Growth differentiation factor 11 (GDF11) belongs to the transforming growth factor-β (TGF-β) superfamily and participates in various pathophysiological processes. Initially, GDF11 was suggested to act as a rejuvenator by improving age-related phenotypes of the heart, brain, and skeletal muscle in aged mice. However, recent studies demonstrate that GDF11 also serves as an adverse risk factor for human frailty and diseases. However, the role of GDF11 in pulmonary fibrosis (PF) remains unclear. In this study, we explored the role and signaling mechanisms of GDF11 in PF. We discovered that GDF11 expression was markedly upregulated in fibrotic lung tissues of both humans and mice. Intratracheal administration of commercial recombinant GDF11 caused lung injury, inflammation, and fibrogenesis in mice. Furthermore, adenovirus-mediated secretory expression of mature GDF11 was exacerbated, whereas full-length GDF11 or the GDF11 propeptide (GDF111-298) alleviated bleomycin-induced PF in mice. In vitro experiments demonstrated that GDF11 suppressed the growth of alveolar and bronchial epithelial cells (A549 and BEAS-2B) and pulmonary microvascular endothelial cells (HPMVEC), promoted fibroblast activation, and induced epithelial/endothelial-mesenchymal transition (EMT/EndoMT). These effects corresponded to the phosphorylation of Smad2/3, and blocking ALK5-Smad2/3 signaling abolished the in vivo and in vitro effects of GDF11. In conclusion, our findings provide evidence that GDF11 acts as a potent injurious, pro-inflammatory, and pro-fibrotic factor in the lungs via the ALK5-Smad2/3 pathway.

Reduction in Renal Interstitial Fibrosis in Aged Male Mice by Intestinal Microbiota Rejuvenation

INTRODUCTION

Renal interstitial fibrosis is an important pathological basis for kidney ageing and the progression of ageing nephropathy. In the present research, we established an aged mouse model of faecal microbiota transplantation (FMT), identified the rejuvenation features of the kidney in aged male mice, and preliminarily analysed the possible mechanism by which the rejuvenation of the intestinal microbiota reduces renal interstitial fibrosis and delays senescence in aged male mice.

METHODS

We established an aged male mice model that was treated with FMT (FMT-Old) and a normal aged male mice control group (Old). Differentially expressed cytokines were identified using a cytokine array, and changes in protein expression related to signal transduction pathways in renal tissues were detected using a signalling pathway array. Senescence-associated β-galactosidase and Masson staining were performed to observe the degrees of renal senescence and tubule interstitial fibrosis. Immunohistochemistry was utilized to detect changes in the expression of the ageing markers p53 and p21 and the inflammation-related protein nuclear factor (NF-κB) subunit (RelA/p65).

RESULTS

The pathological features of renal senescence in the FMT-Old group were significantly alleviated, and the levels of the ageing indicators p53 and p21 were decreased (p < 0.05). Ingenuity Pathway Analysis revealed that six differentially expressed cytokines, MIP-3β (CCL-19), E-selectin (SELE), Fas ligand (Fas L/FASLG), CXCL-11 (I-TAC), CXCL-1 and CCL-3 (MIP-1α) were related to a common upstream regulatory protein, RelA/p65, and the expression of this protein was significantly different between groups according to the signalling pathway array.

CONCLUSION

Our findings suggest that the intestinal microbiota regulates the renal microenvironment by reducing immune inflammatory responses through the inhibition of the NF-κB signalling pathway, thereby delaying renal senescence in aged male mice.

Ophthalmic acid is a bloodborne metabolite that contributes to age-induced cardiomyocyte hypertrophy

Cardiac aging involves the development of left ventricular hypertrophy alongside a decline in functional capacity. Here, we use neutral blood exchange to demonstrate that the acute removal of age-accumulated blood factors significantly regresses cardiac hypertrophy in aged mice. The reversal of hypertrophy was not attributed to age-associated hemodynamic effects, implicating a role of blood-derived factors. In addition, the overarching paradigm of systemic aging maintains that the age-related overabundance of plasma proteins are largely responsible for causing pathological phenotypes in tissues. Our results suggest that blood metabolites, not proteins, drive cardiac hypertrophy instead. Upon analyzing serum metabolomics data sets, we identified ophthalmic acid as a circulating metabolite whose levels increase with advanced age. Treatment of adult mouse and neonatal rat cardiomyocytes in culture with ophthalmic acid increased their relative surface areas. This study uncovers a non-protein metabolite that may contribute to cardiomyocyte hypertrophy during aging. Identifying a method to counteract ophthalmic acid's hypertrophic effects may reveal novel therapeutic opportunities for cardiac rejuvenation.

Cardiac Molecular Analysis Reveals Aging-Associated Metabolic Alterations Promoting Glycosaminoglycans Accumulation via Hexosamine Biosynthetic Pathway

Age is a prominent risk factor for cardiometabolic disease, often leading to heart structural and functional changes. However, precise molecular mechanisms underlying cardiac remodeling and dysfunction exclusively resulting from physiological aging remain elusive. Previous research demonstrated age-related functional alterations in baboons, analogous to humans. The goal of this study is to identify early cardiac molecular alterations preceding functional adaptations, shedding light on the regulation of age-associated changes. Unbiased transcriptomics of left ventricle samples are performed from female baboons aged 7.5-22.1 years (human equivalent ≈30-88 years). Weighted-gene correlation network and pathway enrichment analyses are performed, with histological validation. Modules of transcripts negatively correlated with age implicated declined metabolism-oxidative phosphorylation, tricarboxylic acid cycle, glycolysis, and fatty-acid β-oxidation. Transcripts positively correlated with age suggested a metabolic shift toward glucose-dependent anabolic pathways, including hexosamine biosynthetic pathway (HBP). This shift is associated with increased glycosaminoglycan synthesis, modification, precursor synthesis via HBP, and extracellular matrix accumulation, verified histologically. Upregulated extracellular matrix-induced signaling coincided with glycosaminoglycan accumulation, followed by cardiac hypertrophy-related pathways. Overall, these findings revealed a transcriptional shift in metabolism favoring glycosaminoglycan accumulation through HBP before cardiac hypertrophy. Unveiling this metabolic shift provides potential targets for age-related cardiac diseases, offering novel insights into early age-related mechanisms.

Rejuvenation of the Aging Heart: Molecular Determinants and Applications

In Canada and worldwide, the elderly population (ie, individuals > 65 years of age) is increasing disproportionately relative to the total population. This is expected to have a substantial impact on the health care system, as increased aged is associated with a greater incidence of chronic noncommunicable diseases. Within the elderly population, cardiovascular disease is a leading cause of death, therefore developing therapies that can prevent or slow disease progression in this group is highly desirable. Historically, aging research has focused on the development of anti-aging therapies that are implemented early in life and slow the age-dependent decline in cell and organ function. However, accumulating evidence supports that late-in-life therapies can also benefit the aged cardiovascular system by limiting age-dependent functional decline. Moreover, recent studies have demonstrated that rejuvenation (ie, reverting cellular function to that of a younger phenotype) of the already aged cardiovascular system is possible, opening new avenues to develop therapies for older individuals. In this review, we first provide an overview of the functional changes that occur in the cardiomyocyte with aging and how this contributes to the age-dependent decline in heart function. We then discuss the various anti-aging and rejuvenation strategies that have been pursued to improve the function of the aged cardiomyocyte, with a focus on therapies implemented late in life. These strategies include 1) established systemic approaches (caloric restriction, exercise), 2) pharmacologic approaches (mTOR, AMPK, SIRT1, and autophagy-targeting molecules), and 3) emerging rejuvenation approaches (partial reprogramming, parabiosis/modulation of circulating factors, targeting endogenous stem cell populations, and senotherapeutics). Collectively, these studies demonstrate the exciting potential and limitations of current rejuvenation strategies and highlight future areas of investigation that will contribute to the development of rejuvenation therapies for the aged heart.

Whole-Genome Resequencing Reveals Genetic Diversity and Growth Trait-Related Genes in Pinan Cattle

The breeding of high-quality beef cattle breeds is crucial for the development of animal husbandry, and whole-genome resequencing is widely applicated in the field of molecular breeding. Advantages in growth and reproductive traits exist in Pinan cattle compared with other cattle breeds, but there is limited research on its genomic mechanism. Using whole-genome resequencing, the genetic structure and genomic selection signatures in Pinan cattle were investigated in this study. Phylogenetic, cluster, and admixture analysis results indicated that Pinan cattle have a closer genetic relationship with Kholmogory cattle and China north cattle breeds. Through a selective sweep strategy, 207 and 54 candidate genes related to growth and reproduction and immunity, respectively, were identified in the Pinan cattle population. Given the crucial role of the glutamate-cysteine ligase catalytic (GCLC) gene in muscle antioxidative defense, the high frequency of allele T of the GCLC c.429 C>T locus in the Pinan cattle population might partially contribute to the advantages of Pinan cattle in growth performance. This study laid the foundation for the genetic improvement in Chinese local beef cattle and provide background for the studies on the growth and development of Pinan cattle.

Polygenic proxies of age-related plasma protein levels reveal TIMP2 role in cognitive performance

Several studies have identified blood proteins that influence brain aging performance in mice, yet translating these findings to humans remains challenging. Here we found that higher predicted plasma levels of Tissue Inhibitor of Metalloproteinases 2 (TIMP2) were significantly associated with improved global cognition and memory performance in humans. We first identified 12 proteins with aging or rejuvenating effects on murine brains through a systematic review. Using protein quantitative trait loci data for these proteins, we computed polygenic scores as proxies for plasma protein levels and validated their prediction accuracy in two independent cohorts. Association models between genetic proxies and cognitive performance highlighted the significance of TIMP2, also when the models were stratified by sex, APOE -ε4, and Aβ42 status. This finding aligns with TIMP2's brain-rejuvenating role in murine models, suggesting it as a promising therapeutic target for brain aging and age-related brain diseases in humans.

Expression profiling by high-throughput sequencing reveals GADD45, SMAD7, EGR-1 and HOXA3 activation in Myostatin (MSTN) and GDF11 treated myoblasts

Growth differentiation factor 11 (GDF11) and myostatin (MSTN/GDF8) are closely related members of the transforming growth factor β (TGFβ) superfamily, sharing structural homology. Despite these structural similarities, recent research has shed light on the distinct roles these ligands play within muscle tissue. This study aims to uncover both the differences and similarities in gene expression at the transcriptome level by utilizing RNA sequencing. We conducted experiments involving five distinct groups, each with three biological replicates, using C2C12 cell cultures. The cells were subjected to high-throughput profiling to investigate disparities in gene expression patterns following preconditioning with either GDF11 or MSTN at concentrations of 1 nM and 10 nM, respectively. In addition, control groups were established. Our research revealed concentration-dependent gene expression patterns, with 38 genes showing significant differences when compared to the control groups. Notably, GADD45, SMAD7, EGR-1, and HOXA3 exhibited significant differential expression. We also conducted an over-representation analysis, highlighting the activation of MAPK and JNK signaling pathways, along with GO-terms related to genes that negatively regulate metabolic processes, biosynthesis, and protein phosphorylation. This study unveiled the activation of several genes not previously discussed in existing literature whose full biological implications are yet to be determined in future research.

Rejuvenation of young blood on aging organs: Effects, circulating factors, and mechanisms

Aging causes degenerative changes in organs, leading to a decline in physical function. Over the past two decades, researchers have made significant progress in understanding the rejuvenating effects of young blood on aging organs, benefiting from heterochronic parabiosis models that connect the blood circulation of aged and young rodents. It has been discovered that young blood can partially rejuvenate organs in old animals by regulating important aging-related signaling pathways. Clinical trials have also shown the effectiveness of young blood in treating aging-related diseases. However, the limited availability of young blood poses a challenge to implementing anti-aging therapies on a large scale for older individuals. As a promising alternative, scientists have identified some specific anti-aging circulating factors in young blood that have been shown to promote organ regeneration, reduce inflammation, and alleviate fibrosis associated with aging in animal experiments. While previous reviews have focused primarily on the effects and mechanisms of circulating factors on aging, it is important to acknowledge that studying the rejuvenating effects and mechanisms of young blood has been a significant source of inspiration in this field, and it will continue to be in the future. In recent years, new findings have emerged, further expanding our knowledge in this area. This review aims to summarize the rejuvenating effects and mechanisms of young blood and circulating factors, discussing their similarities and connections, addressing discrepancies in previous studies, outlining future research directions, and highlighting the potential for clinical translation in anti-aging interventions.

GDF11 (Protein of Juvenility) and GDF15 (Protein of Senility) in the Plasma of Patients with Sleep Apnea Syndrome: a Pilot Study

We performed a matched-pair analysis of the content of GDF11 and GDF15 proteins in the plasma of patients (56 middle-aged men) with obstructive sleep apnea syndrome (OSAS) and healthy volunteers (27 men with no complaints of sleep disorders). The groups were comparable in terms of age and presence of chronic diseases. No statistically significant differences in GDF11 content in the studied groups were revealed, while the content of GDF15 in the OSAS group was 1.3 times higher. These results require further research from the viewpoint of geriatric somnology and molecular biology.

Aging as a loss of morphostatic information: A developmental bioelectricity perspective

Maintaining order at the tissue level is crucial throughout the lifespan, as failure can lead to cancer and an accumulation of molecular and cellular disorders. Perhaps, the most consistent and pervasive result of these failures is aging, which is characterized by the progressive loss of function and decline in the ability to maintain anatomical homeostasis and reproduce. This leads to organ malfunction, diseases, and ultimately death. The traditional understanding of aging is that it is caused by the accumulation of molecular and cellular damage. In this article, we propose a complementary view of aging from the perspective of endogenous bioelectricity which has not yet been integrated into aging research. We propose a view of aging as a morphostasis defect, a loss of biophysical prepattern information, encoding anatomical setpoints used for dynamic tissue and organ homeostasis. We hypothesize that this is specifically driven by abrogation of the endogenous bioelectric signaling that normally harnesses individual cell behaviors toward the creation and upkeep of complex multicellular structures in vivo. Herein, we first describe bioelectricity as the physiological software of life, and then identify and discuss the links between bioelectricity and life extension strategies and age-related diseases. We develop a bridge between aging and regeneration via bioelectric signaling that suggests a research program for healthful longevity via morphoceuticals. Finally, we discuss the broader implications of the homologies between development, aging, cancer and regeneration and how morphoceuticals can be developed for aging.

Blood-based therapies to combat neurodegenerative diseases

Neurodegeneration, known as the progressive loss of neurons in terms of their structure and function, is the principal pathophysiological change found in the majority of brain-related disorders. Ageing has been considered the most well-established risk factor in most common neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD). There is currently no effective treatment or cure for these diseases; the approved therapeutic options to date are only for palliative care. Ageing and neurodegenerative diseases are closely intertwined; reversing the aspects of brain ageing could theoretically mitigate age-related neurodegeneration. Ever since the regenerative properties of young blood on aged tissues came to light, substantial efforts have been focused on identifying and characterizing the circulating factors in the young and old systemic milieu that may attenuate or accentuate brain ageing and neurodegeneration. Later studies discovered the superiority of old plasma dilution in tissue rejuvenation, which is achieved through a molecular reset of the systemic proteome. These findings supported the use of therapeutic blood exchange for the treatment of degenerative diseases in older individuals. The first objective of this article is to explore the rejuvenating properties of blood-based therapies in the ageing brains and their therapeutic effects on AD. Then, we also look into the clinical applications, various limitations, and challenges associated with blood-based therapies for AD patients.

Growth differentiation factor 11 regulates high glucose-induced cardiomyocyte pyroptosis and diabetic cardiomyopathy by inhibiting inflammasome activation

BACKGROUND

Diabetic cardiomyopathy (DCM) is a crucial complication of long-term chronic diabetes that can lead to myocardial hypertrophy, myocardial fibrosis, and heart failure. There is increasing evidence that DCM is associated with pyroptosis, a form of inflammation-related programmed cell death. Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily, which regulates oxidative stress, inflammation, and cell survival to mitigate myocardial hypertrophy, myocardial infarction, and vascular injury. However, the role of GDF11 in regulating pyroptosis in DCM remains to be elucidated. This research aims to investigate the role of GDF11 in regulating pyroptosis in DCM and the related mechanism.

METHODS AND RESULTS

Mice were injected with streptozotocin (STZ) to induce a diabetes model. H9c2 cardiomyocytes were cultured in high glucose (50 mM) to establish an in vitro model of diabetes. C57BL/6J mice were preinjected with adeno-associated virus 9 (AAV9) intravenously via the tail vein to specifically overexpress myocardial GDF11. GDF11 attenuated pyroptosis in H9c2 cardiomyocytes after high-glucose treatment. In diabetic mice, GDF11 alleviated cardiomyocyte pyroptosis, reduced myocardial fibrosis, and improved cardiac function. Mechanistically, GDF11 inhibited pyroptosis by preventing inflammasome activation. GDF11 achieved this by specifically binding to apoptosis-associated speck-like protein containing a CARD (ASC) and preventing the assembly and activation of the inflammasome. Additionally, the expression of GDF11 during pyroptosis was regulated by peroxisome proliferator-activated receptor α (PPARα).

CONCLUSION

These findings demonstrate that GDF11 can treat diabetic cardiomyopathy by alleviating pyroptosis and reveal the role of the PPARα-GDF11-ASC pathway in DCM, providing ideas for new strategies for cardioprotection.

In vitro heterochronic parabiosis identifies pigment epithelium-derived factor as a systemic mediator of rejuvenation by young blood

Several decades of heterochronic parabiosis (HCPB) studies have demonstrated the restorative impact of young blood, and deleterious influence of aged blood, on physiological function and homeostasis across tissues, although few of the factors responsible for these observations have been identified. Here we develop an in vitro HCPB system to identify these circulating factors, using replicative lifespan (RLS) of primary human fibroblasts as an endpoint of cellular health. We find that RLS is inversely correlated with serum donor age and sensitive to the presence or absence of specific serum components. Through in vitro HCPB, we identify the secreted protein pigment epithelium-derived factor (PEDF) as a circulating factor that extends RLS of primary human fibroblasts and declines with age in mammals. Systemic administration of PEDF to aged mice reverses age-related functional decline and pathology across several tissues, improving cognitive function and reducing hepatic fibrosis and renal lipid accumulation. Together, our data supports PEDF as a systemic mediator of the effect of young blood on organismal health and homeostasis and establishes our in vitro HCPB system as a valuable screening platform for the identification of candidate circulating factors involved in aging and rejuvenation.

A Senescence-Associated Secretory Phenotype of Bone Marrow Mesenchymal Stem Cells Inhibits the Viability of Breast Cancer Cells

Breast cancer, the most prevalent malignancy in women, often progresses to bone metastases, especially in older individuals. Dormancy, a critical aspect of bone-metastasized breast cancer cells (BCCs), enables them to evade treatment and recur. This dormant state is regulated by bone marrow mesenchymal stem cells (BMMSCs) through the secretion of various factors, including those associated with senescence. However, the specific mechanisms by which BMMSCs induce dormancy in BCCs remain unclear. To address this gap, a bone-specific senescence-accelerated murine model, SAMP6, was utilized to minimize confounding systemic age-related factors. Confirming senescence-accelerated osteoporosis, distinct BMMSC phenotypes were observed in SAMP6 mice compared to SAMR1 counterparts. Notably, SAMP6-BMMSCs exhibited premature senescence primarily due to telomerase activity loss and activation of the p21 signaling pathway. Furthermore, the effects of conditioned medium (CM) derived from SAMP6-BMMSCs versus SAMR1-BMMSCs on BCC proliferation were examined. Intriguingly, only CM from SAMP6-BMMSCs inhibited BCC proliferation by upregulating p21 expression in both MCF-7 and MDA-MB-231 cells. These findings suggest that the senescence-associated secretory phenotype (SASP) of BMMSCs suppresses BCC viability by inducing p21, a pivotal cell cycle inhibitor and tumor suppressor. This highlights a heightened susceptibility of BCCs to dormancy in a senescent microenvironment, potentially contributing to the increased incidence of breast cancer bone metastasis and recurrence observed with aging.

In chronic kidney disease altered cardiac metabolism precedes cardiac hypertrophy

Conduit arterial disease in chronic kidney disease (CKD) is an important cause of cardiac complications. Cardiac function in CKD has not been studied in the absence of arterial disease. In an Alport syndrome model bred not to have conduit arterial disease, mice at 225 days of life (dol) had CKD equivalent to humans with CKD stage 4-5. Parathyroid hormone (PTH) and FGF23 levels were one log order elevated, circulating sclerostin was elevated, and renal activin A was strongly induced. Aortic Ca levels were not increased, and vascular smooth muscle cell (VSMC) transdifferentiation was absent. The CKD mice were not hypertensive, and cardiac hypertrophy was absent. Freshly excised cardiac tissue respirometry (Oroboros) showed that ADP-stimulated O2 flux was diminished from 52 to 22 pmol/mg (P = 0.022). RNA-Seq of cardiac tissue from CKD mice revealed significantly decreased levels of cardiac mitochondrial oxidative phosphorylation genes. To examine the effect of activin A signaling, some Alport mice were treated with a monoclonal Ab to activin A or an isotype-matched IgG beginning at 75 days of life until euthanasia. Treatment with the activin A antibody (Ab) did not affect cardiac oxidative phosphorylation. However, the activin A antibody was active in the skeleton, disrupting the effect of CKD to stimulate osteoclast number, eroded surfaces, and the stimulation of osteoclast-driven remodeling. The data reported here show that cardiac mitochondrial respiration is impaired in CKD in the absence of conduit arterial disease. This is the first report of the direct effect of CKD on cardiac respiration.NEW & NOTEWORTHY Heart disease is an important morbidity of chronic kidney disease (CKD). Hypertension, vascular stiffness, and vascular calcification all contribute to cardiac pathophysiology. However, cardiac function in CKD devoid of vascular disease has not been studied. Here, in an animal model of human CKD without conduit arterial disease, we analyze cardiac respiration and discover that CKD directly impairs cardiac mitochondrial function by decreasing oxidative phosphorylation. Protection of cardiac oxidative phosphorylation may be a therapeutic target in CKD.

Energy metabolism as therapeutic target for aged wound repair by engineered extracellular vesicle

Aging skin, vulnerable to age-related defects, is poor in wound repair. Metabolic regulation in accumulated senescent cells (SnCs) with aging is essential for tissue homeostasis, and adequate ATP is important in cell activation for aged tissue repair. Strategies for ATP metabolism intervention hold prospects for therapeutic advances. Here, we found energy metabolic changes in aging skin from patients and mice. Our data show that metformin engineered EV (Met-EV) can enhance aged mouse skin repair, as well as ameliorate cellular senescence and restore cell dysfunctions. Notably, ATP metabolism was remodeled as reduced glycolysis and enhanced OXPHOS after Met-EV treatment. We show Met-EV rescue senescence-induced mitochondria dysfunctions and mitophagy suppressions, indicating the role of Met-EV in remodeling mitochondrial functions via mitophagy for adequate ATP production in aged tissue repair. Our results reveal the mechanism for SnCs rejuvenation by EV and suggest the disturbed energy metabolism, essential in age-related defects, to be a potential therapeutic target for facilitating aged tissue repair.

GDF11 level and its effect on prognosis in patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the proliferation of CD34 positive self-renewing malignant hematopoietic stem cells. Previous studies have shown that the transforming growth factor beta (TGFβ) pathway plays a role in AML pathogenesis, especially by affecting the microenvironment. Growth differentiation factor 11 (GDF11) is a member of the TGFβ superfamily, involved in embryological development and known as rejuvenating factor. In this study, our aim was to determine the serum GDF11 level in patients with AML, to compare it with the control group, to determine its relationship with follistatin, vimentin, and E-cadherin levels, and to determine whether GDF11 influences AML prognosis. Serum GDF11, vimentin, follistatin, and E-cadherin levels of newly diagnosed or relapsed/refractory AML patients and age- and gender-matched control group were measured by enzyme-linked immunosorbent assay. Serum GDF11 level was higher in the patient group (263.87 ± 126.54 ng/L) compared to the control group (211.54 ± 61.47 ng/L; p = 0.035). GDF11 level did not change according to age, gender, hemoglobin level, and bone marrow blast rate. No correlation was found between GDF11 level, response rates, and survival status of the patients. A positive correlation was detected between GDF11, E-cadherin, and vimentin levels. As a conclusion, increased serum GDF11 levels in AML patients may be linked to the regeneration ability of leukemic stem cells. There is a need for studies investigating GDF11 expression in myeloblasts.

Progress in the relationship between GDF11 and depression

Annually, the frequency of morbidity in depression has increased progressively in response to life stressors, and there is an increasing trend toward younger morbidity. The pathogenesis of depression is complicated and includes factors such as genetic inheritance and variations in physiological functions induced by various environmental factors. Currently, drug therapy has wide adaptability in clinical practice and plays an important role in the treatment of patients with mild depression. However, the therapeutic effects of most antidepressants are typically not significant and are associated with considerable adverse effects and addiction. Therefore, it is imperative to identify the deeper mechanisms of depression and search for alternative drug targets. Growth differentiation factor 11 (GDF11) is described as an anti-ageing molecule that belongs to a member of the transforming growth factor β family. Additionally, the latest research findings suggested that GDF11 positively regulates neurogenesis and enhances neuronal activity, thereby attenuating depression-like behaviours. Although an increasing number of studies have focused on the multiple functions of GDF11 in skeletal dysplasia and carcinogenesis, its precise mechanism of action in depression remains unknown. Thus, in this review, we discuss the role of GDF11 and its mechanistic pathways in the pathogenesis of depression to develop novel therapies for depression.

Unlocking the dark matter: noncoding RNAs and RNA modifications in cardiac aging

Cardiac aging is a multifaceted process that encompasses structural and functional alterations culminating in heart failure. As the elderly population continues to expand, there is a growing urgent need for interventions to combat age-related cardiac functional decline. Noncoding RNAs have emerged as critical regulators of cellular and biochemical processes underlying cardiac disease. This review summarizes our current understanding of how noncoding RNAs function in the heart during aging, with particular emphasis on mechanisms of RNA modification that control their activity. Targeting noncoding RNAs as potential novel therapeutics in cardiac aging is also discussed.

GDF11 mitigates high glucose-induced cardiomyocytes apoptosis by inhibiting the ALKBH5-FOXO3-CDR1as/Hippo signaling pathway

Diabetic cardiomyopathy remains a formidable health challenge with a high mortality rate and no targeted treatments. Growth differentiation factor 11 (GDF11) has shown promising effects on cardiovascular diseases; however, its role and the underlying mechanism in regulating diabetic cardiomyopathy remain unclear. In this study, we developed mouse models of diabetic cardiomyopathy using leptin receptor-deficient (db/db) mice and streptozocin-induced C57BL/6 mice. The diabetic cardiomyopathy model mice exhibited apparent structural damage in cardiac tissues and a significant increase in the expression of apoptosis-related proteins. Notably, we observed a significant decreased expression of GDF11 in the myocardium of mice with diabetic cardiomyopathy. Moreover, GDF11 cardiac-specific knock-in mice (transgenic mice) exhibited improved cardiac function and reduced apoptosis. Moreover, exogenous administration of GDF11 mitigated high glucose-induced cardiomyocyte apoptosis. Mechanistically, we demonstrated that GDF11 alleviated high glucose-induced cardiomyocytes apoptosis by inhibiting the activation of the alkylation repair homolog 5 (ALKBH5)-forkhead box group O3a (FOXO3)-cerebellar degeneration-related protein 1 transcript (CDR1as)/Hippo signaling pathway. Consequently, this novel mechanism effectively counteracted myocardial cell apoptosis, providing valuable insights into potential therapeutic strategies for clinical diabetic cardiomyopathy.

Antiaging Strategies and Remedies: A Landscape of Research Progress and Promise

Aging is typified by a gradual loss of physiological fitness and accumulation of cellular damage, leading to deteriorated functions and enhanced vulnerability to diseases. Antiaging research has a long history throughout civilization, with many efforts put forth to understand and prevent the effects of aging. Multiple strategies aiming to promote healthy aging and extend the lifespan have been developed including lifestyle adjustments, medical treatments, and social programs. A multitude of antiaging medicines and remedies have also been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent research related to antiaging strategies and treatments. We review the recent advances and delineate trends in research headway of antiaging knowledge and practice across time, geography, and development pipelines. We further assess the state-of-the-art antiaging approaches and explore their correlations with age-related diseases. The landscape of antiaging drugs has been outlined and explored. Well-recognized and novel, currently evaluated antiaging agents have also been summarized. Finally, we review clinical applications of antiaging products with their development pipelines. The objective of this review is to summarize current knowledge on preventive strategies and treatment remedies in the field of aging, to outline challenges and evaluate growth opportunities, in order to further efforts to solve the problems that remain.

Rejuvenation of cerebromicrovascular function in aged mice through heterochronic parabiosis: insights into neurovascular coupling and the impact of young blood factors

Age-related impairment of neurovascular coupling (NVC; "functional hyperemia") is a critical factor in the development of vascular cognitive impairment (VCI). Recent geroscience research indicates that cell-autonomous mechanisms alone cannot explain all aspects of neurovascular aging. Circulating factors derived from other organs, including pro-geronic factors (increased with age and detrimental to vascular homeostasis) and anti-geronic factors (preventing cellular aging phenotypes and declining with age), are thought to orchestrate cellular aging processes. This study aimed to investigate the influence of age-related changes in circulating factors on neurovascular aging. Heterochronic parabiosis was utilized to assess how exposure to young or old systemic environments could modulate neurovascular aging. Results demonstrated a significant decline in NVC responses in aged mice subjected to isochronic parabiosis (20-month-old C57BL/6 mice [A-(A)]; 6 weeks of parabiosis) when compared to young isochronic parabionts (6-month-old, [Y-(Y)]). However, exposure to young blood from parabionts significantly improved NVC in aged heterochronic parabionts [A-(Y)]. Conversely, young mice exposed to old blood from aged parabionts exhibited impaired NVC responses [Y-(A)]. In conclusion, even a brief exposure to a youthful humoral environment can mitigate neurovascular aging phenotypes, rejuvenating NVC responses. Conversely, short-term exposure to an aged humoral milieu in young mice accelerates the acquisition of neurovascular aging traits. These findings highlight the plasticity of neurovascular aging and suggest the presence of circulating anti-geronic factors capable of rejuvenating the aging cerebral microcirculation. Further research is needed to explore whether young blood factors can extend their rejuvenating effects to address other age-related cerebromicrovascular pathologies, such as blood-brain barrier integrity.

To squeeze or not: Regulation of cell size by mechanical forces in development and human diseases

Physical constraints, such as compression, shear stress, stretching and tension play major roles during development and tissue homeostasis. Mechanics directly impact physiology, and their alteration is also recognized as having an active role in driving human diseases. Recently, growing evidence has accumulated on how mechanical forces are translated into a wide panel of biological responses, including metabolism and changes in cell morphology. The aim of this review is to summarize and discuss our knowledge on the impact of mechanical forces on cell size regulation. Other biological consequences of mechanical forces will not be covered by this review. Moreover, wherever possible, we also discuss mechanosensors and molecular and cellular signaling pathways upstream of cell size regulation. We finally highlight the relevance of mechanical forces acting on cell size in physiology and human diseases.

Large scale plasma proteomics identifies novel proteins and protein networks associated with heart failure development

Heart failure (HF) causes substantial morbidity and mortality but its pathobiology is incompletely understood. The proteome is a promising intermediate phenotype for discovery of novel mechanisms. We measured 4877 plasma proteins in 13,900 HF-free individuals across three analysis sets with diverse age, geography, and HF ascertainment to identify circulating proteins and protein networks associated with HF development. Parallel analyses in Atherosclerosis Risk in Communities study participants in mid-life and late-life and in Trøndelag Health Study participants identified 37 proteins consistently associated with incident HF independent of traditional risk factors. Mendelian randomization supported causal effects of 10 on HF, HF risk factors, or left ventricular size and function, including matricellular (e.g. SPON1, MFAP4), senescence-associated (FSTL3, IGFBP7), and inflammatory (SVEP1, CCL15, ITIH3) proteins. Protein co-regulation network analyses identified 5 modules associated with HF risk, two of which were influenced by genetic variants that implicated trans hotspots within the VTN and CFH genes.

Serum-Induced Proliferation of Human Cardiac Stem Cells Is Modulated via TGFβRI/II and SMAD2/3

The ageing phenotype is strongly driven by the exhaustion of adult stem cells (ASCs) and the accumulation of senescent cells. Cardiovascular diseases (CVDs) and heart failure (HF) are strongly linked to the ageing phenotype and are the leading cause of death. As the human heart is considered as an organ with low regenerative capacity, treatments targeting the rejuvenation of human cardiac stem cells (hCSCs) are of great interest. In this study, the beneficial effects of human blood serum on proliferation and senescence of hCSCs have been investigated at the molecular level. We show the induction of a proliferation-related gene expression response by human blood serum at the mRNA level. The concurrent differential expression of the TGFβ target and inhibitor genes indicates the participation of TGFβ signalling in this context. Surprisingly, the application of TGFβ1 as well as the inhibition of TGFβ type I and type II receptor (TGFβRI/II) signalling strongly increased the proliferation of hCSCs. Likewise, both human blood serum and TGFβ1 reduced the senescence in hCSCs. The protective effect of serum on senescence in hCSCs was enhanced by simultaneous TGFβRI/II inhibition. These results strongly indicate a dual role of TGFβ signalling in terms of the serum-mediated effects on hCSCs. Further analysis via RNA sequencing (RNA-Seq) revealed the participation of Ras-inactivating genes wherefore a prevention of hyperproliferation upon serum-treatment in hCSCs via TGFβ signalling and Ras-induced senescence is suggested. These insights may improve treatments of heart failure in the future.

Circulating Growth Differentiation Factors 11 and 8, Their Antagonists Follistatin and Follistatin-Like-3, and Risk of Heart Failure in Elders

BACKGROUND

Heterochronic parabiosis has identified growth differentiation factor (GDF)-11 as a potential means of cardiac rejuvenation, but findings have been inconsistent. A major barrier has been lack of assay specificity for GDF-11 and its homolog GDF-8.

METHODS

We tested the hypothesis that GDF-11 and GDF-8, and their major antagonists follistatin and follistatin-like (FSTL)-3, are associated with incident heart failure (HF) and its subtypes in elders. Based on validation experiments, we used liquid chromatography-tandem mass spectrometry to measure total serum GDF-11 and GDF-8, along with follistatin and FSTL-3 by immunoassay, in 2 longitudinal cohorts of older adults.

RESULTS

In 2 599 participants (age 75.2 ± 4.3) followed for 10.8 ± 5.6 years, 721 HF events occurred. After adjustment, neither GDF-11 (HR per doubling: 0.93 [0.67, 1.30]) nor GDF-8 (HR: 1.02 per doubling [0.83, 1.27]) was associated with incident HF or its subtypes. Positive associations with HF were detected for follistatin (HR: 1.15 [1.00, 1.32]) and FLST-3 (HR: 1.38 [1.03, 1.85]), and with HF with preserved ejection fraction for FSTL-3 (HR: 1.77 [1.03, 3.02]). (All HRs per doubling of biomarker.) FSTL-3 associations with HF appeared stronger at higher follistatin levels and vice versa, and also for men, Blacks, and lower kidney function.

CONCLUSIONS

Among older adults, serum follistatin and FSTL-3, but not GDF-11 or GDF-8, were associated with incident HF. These findings do not support the concept that low serum levels of total GDF-11 or GDF-8 contribute to HF late in life, but do implicate transforming growth factor-β superfamily pathways as potential therapeutic targets.

Aging and age-related diseases with a focus on therapeutic potentials of young blood/plasma

Aging is accompanied by alterations in the body with time-related to decline of physiological integrity and functionality process, responsible for increasing diseases and vulnerability to death. Several ages associated with biomarkers were observed in red blood cells, and consequently plasma proteins have a critical rejuvenating role in the aging process and age-related disorders. Advanced age is a risk factor for a broad spectrum of diseases and disorders such as cardiovascular diseases, musculoskeletal disorders and liver, chronic kidney disease, neurodegenerative diseases, and cancer because of loss of regenerative capacity, correlated to reduced systemic factors and raise of pro-inflammatory cytokines. Most studies have shown that systemic factors in young blood/plasma can strongly protect against age-related diseases in various tissues by restoring autophagy, increasing neurogenesis, and reducing oxidative stress, inflammation, and apoptosis. Here, we focus on the current advances in using young plasma or blood to combat aging and age-related diseases and summarize the experimental and clinical evidence supporting this approach. Based on reports, young plasma or blood is new a therapeutic approach to aging and age-associated diseases.

Circulating GDF11 exacerbates myocardial injury in mice and associates with increased infarct size in humans

AIMS

The heart rejuvenating effects of circulating growth differentiation factor 11 (GDF11), a transforming growth factor-β superfamily member that shares 90% homology with myostatin (MSTN), remains controversial. Here, we aimed to probe the role of GDF11 in acute myocardial infarction (MI), a frequent cause of heart failure and premature death during ageing.

METHODS AND RESULTS

In contrast to endogenous Mstn, myocardial Gdf11 declined during the course of ageing and was particularly reduced following ischaemia/reperfusion (I/R) injury, suggesting a therapeutic potential of GDF11 signalling in MI. Unexpectedly, boosting systemic Gdf11 by recombinant GDF11 delivery (0.1 mg/kg body weight over 30 days) prior to myocardial I/R augmented myocardial infarct size in C57BL/6 mice irrespective of their age, predominantly by accelerating pro-apoptotic signalling. While intrinsic cardioprotective signalling pathways remained unaffected by high circulating GDF11, targeted transcriptomics and immunomapping studies focusing on GDF11-associated downstream targets revealed attenuated Nkx2-5 expression confined to CD105-expressing cells, with pro-apoptotic activity, as assessed by caspase-3 levels, being particularly pronounced in adjacent cells, suggesting an indirect effect. By harnessing a highly specific and validated liquid chromatography-tandem mass spectrometry-based assay, we show that in prospectively recruited patients with MI circulating GDF11 but not MSTN levels incline with age. Moreover, GDF11 levels were particularly elevated in those at high risk for adverse outcomes following the acute event, with circulating GDF11 emerging as an independent predictor of myocardial infarct size, as estimated by standardized peak creatine kinase-MB levels.

CONCLUSION

Our data challenge the initially reported heart rejuvenating effects of circulating GDF11 and suggest that high levels of systemic GDF11 exacerbate myocardial injury in mice and humans alike. Persistently high GDF11 levels during ageing may contribute to the age-dependent loss of cardioprotective mechanisms and thus poor outcomes of elderly patients following acute MI.

Systemic changes induced by autologous stem cell ovarian transplant in plasma proteome of women with impaired ovarian reserves

Patients with poor ovarian response (POR) and premature ovarian insufficiency (POI) are challenging to treat, with oocyte donation remaining as the only feasible option to achieve pregnancy in some cases. The Autologous stem cell ovarian transplantation (ASCOT) technique allows follicle development, enabling pregnancies and births of healthy babies in these patients. Previous results suggest that growth factors and cytokines secreted by stem cells are partially responsible for their regenerative properties. Indeed, ASCOT beneficial effects associate with the presence of different bone marrow derived stem cell- secreted factors in plasma. Therefore, the aim of this study was to assess whether ASCOT induce any modifications in the plasma proteomic profile of patients with impaired ovarian reserves. Discriminant analysis highlighted clear distinctions between the plasma proteome before (PRE), during stem cell mobilization and collection (APHERESIS) and three months after ASCOT (POST) in patients with POR and POI. Both the stem cell mobilization and ASCOT technique induced statistically significant modifications in the plasma composition, reversing some age-related protein expression changes. In the POR group, functional analysis revealed an enrichment in processes related to the complement cascade, immune system, and platelet degranulation, while in the POI group, enriched processes were also associated with responses to oxygen-containing compounds and growth hormones, and blood vessel maturation. In conclusion, our findings highlight the potential proteins and biological processes that may promote the follicle activation and growth observed after ASCOT. Identifying plasma proteins that regenerate aged or damaged ovaries could lead to more effective, targeted and/or preventive therapies for patients.

The regulatory effect of growth differentiation factor 11 on different cells

Growth differentiation factor 11 (GDF11) is one of the important factors in the pathophysiological process of animals. It is widely expressed in many tissues and organs of animals, showing its wide biological activity and potential application value. Previous research has demonstrated that GDF11 has a therapeutic effect on various diseases, such as anti-myocardial aging and anti-tumor. This has not only sparked intense interest and enthusiasm among academics but also spurred some for-profit businesses to attempt to develop GDF11 as a medication for regenerative medicine or anti-aging application. Currently, Sotatercept, a GDF11 antibody drug, is in the marketing application stage, and HS-235 and rGDF11 are in the preclinical research stage. Therefore, we believe that figuring out which cells GDF11 acts on and its current problems should be an important issue in the scientific and commercial communities. Only through extensive, comprehensive research and discussion can we better understand the role and potential of GDF11, while avoiding unnecessary risks and misinformation. In this review, we aimed to summarize the role of GDF11 in different cells and its current controversies and challenges, providing an important reference for us to deeply understand the function of GDF11 and formulate more effective treatment strategies in the future.

Effects of Long-Term Administration of Bovine Bone Gelatin Peptides on Myocardial Hypertrophy in Spontaneously Hypertensive Rats

The research purpose was to investigate the effects and the underlying molecular mechanisms of bovine bone gelatin peptides (BGP) on myocardial hypertrophy in spontaneously hypertensive rats (SHR). BGP relieved myocardial hypertrophy and fibrosis in SHR rats in a dose-dependent manner by reducing the left ventricular mass index, myocardial cell diameter, myocardial fibrosis area, and levels of myocardial hypertrophy markers (atrial natriuretic and brain natriuretic peptide). Label-free quantitative proteomics analysis showed that long-term administration of BGP changed the left ventricle proteomes of SHR. The 37 differentially expressed proteins in the high-dose BGP group participated in multiple signaling pathways associated with cardiac hypertrophy and fibrosis indicating that BGP could play a cardioprotective effect on SHR rats by targeting multiple signaling pathways. Further validation experiments showed that a high dose of BGP inhibited the expression of phosphoinositide 3-kinase (Pi3k), phosphorylated protein kinase B (p-Akt), and transforming growth factor-beta 1 (TGF-β1) in the myocardial tissue of SHR rats. Together, BGP could be an effective candidate for functional nutritional supplements to inhibit myocardial hypertrophy and fibrosis by negatively regulating the TGF-β1 and Pi3k/Akt signaling pathways.

Mutual regulation between GDF11 and TET2 prevents senescence of mesenchymal stem cells

Growth differentiation factor 11 (GDF11) is a putative systemic rejuvenation factor. In this study, we characterized the mechanism by which GDF11 reversed aging of mesenchymal stem cells (MSCs). In culture, aged MSCs proliferate slower and are positive for senescence markers senescence-associated β-galactosidase and P16ink4a . They have shortened telomeres, decreased GDF11 expression, and reduced osteogenic potential. GDF11 can block MSC aging in vitro and reverse age-dependent bone loss in vivo. The antiaging effect of GDF11 is via activation of the Smad2/3-PI3K-AKT-mTOR pathway. Unexpectedly, GDF11 also upregulated a DNA demethylase Tet2, which served as a key mediator for GDF11 to autoregulate itself via demethylation of the GDF11 promoter. Mutation of Tet2 facilitates MSC aging by blocking GDF11 expression. Mutagenesis of Tet2-regulated CpG sites also blocks GDF11 expression, leading to MSC aging. Together, a novel mutual regulatory relationship between GDF11 and an epigenetic factor Tet2 unveiled their antiaging roles.

The rosetta stone of successful ageing: does oral health have a role?

Ageing is an inevitable aspect of life and thus successful ageing is an important focus of recent scientific efforts. The biological process of ageing is mediated through the interaction of genes with environmental factors, increasing the body's susceptibility to insults. Elucidating this process will increase our ability to prevent and treat age-related disease and consequently extend life expectancy. Notably, centenarians offer a unique perspective on the phenomenon of ageing. Current research highlights several age-associated alterations on the genetic, epigenetic and proteomic level. Consequently, nutrient sensing and mitochondrial function are altered, resulting in inflammation and exhaustion of regenerative ability.Oral health, an important contributor to overall health, remains underexplored in the context of extreme longevity. Good masticatory function ensures sufficient nutrient uptake, reducing morbidity and mortality in old age. The relationship between periodontal disease and systemic inflammatory pathologies is well established. Diabetes, rheumatoid arthritis and cardiovascular disease are among the most significant disease burdens influenced by inflammatory oral health conditions. Evidence suggests that the interaction is bi-directional, impacting progression, severity and mortality. Current models of ageing and longevity neglect an important factor in overall health and well-being, a gap that this review intends to illustrate and inspire avenues for future research.

Cardiac Molecular Analysis Reveals Aging-Associated Metabolic Alterations Promoting Glycosaminoglycans Accumulation Via Hexosamine Biosynthetic Pathway

Age is a prominent risk factor for cardiometabolic disease, and often leads to heart structural and functional changes. However, precise molecular mechanisms underlying cardiac remodeling and dysfunction resulting from physiological aging per se remain elusive. Understanding these mechanisms requires biological models with optimal translation to humans. Previous research demonstrated that baboons undergo age-related reduction in ejection fraction and increased heart sphericity, mirroring changes observed in humans. The goal of this study was to identify early cardiac molecular alterations that precede functional adaptations, shedding light on the regulation of age-associated changes. We performed unbiased transcriptomics of left ventricle (LV) samples from female baboons aged 7.5-22.1 years (human equivalent ~30-88 years). Weighted-gene correlation network and pathway enrichment analyses were performed to identify potential age-associated mechanisms in LV, with histological validation. Myocardial modules of transcripts negatively associated with age were primarily enriched for cardiac metabolism, including oxidative phosphorylation, tricarboxylic acid cycle, glycolysis, and fatty-acid β-oxidation. Transcripts positively correlated with age suggest upregulation of glucose uptake, pentose phosphate pathway, and hexosamine biosynthetic pathway (HBP), indicating a metabolic shift towards glucose-dependent anabolic pathways. Upregulation of HBP commonly results in increased glycosaminoglycan precursor synthesis. Transcripts involved in glycosaminoglycan synthesis, modification, and intermediate metabolism were also upregulated in older animals, while glycosaminoglycan degradation transcripts were downregulated with age. These alterations would promote glycosaminoglycan accumulation, which was verified histologically. Upregulation of extracellular matrix (ECM)-induced signaling pathways temporally coincided with glycosaminoglycan accumulation. We found a subsequent upregulation of cardiac hypertrophy-related pathways and an increase in cardiomyocyte width. Overall, our findings revealed a transcriptional shift in metabolism from catabolic to anabolic pathways that leads to ECM glycosaminoglycan accumulation through HBP prior to upregulation of transcripts of cardiac hypertrophy-related pathways. This study illuminates cellular mechanisms that precede development of cardiac hypertrophy, providing novel potential targets to remediate age-related cardiac diseases.

Hematopoietic stem cells through the ages: A lifetime of adaptation to organismal demands

Hematopoietic stem cells (HSCs), which govern the production of all blood lineages, transition through a series of functional states characterized by expansion during fetal development, functional quiescence in adulthood, and decline upon aging. We describe central features of HSC regulation during ontogeny to contextualize how adaptive responses over the life of the organism ultimately form the basis for HSC functional degradation with age. We particularly focus on the role of cell cycle regulation, inflammatory response pathways, epigenetic changes, and metabolic regulation. We then explore how the knowledge of age-related changes in HSC regulation can inform strategies for the rejuvenation of old HSCs.

Disorganization of secondary lymphoid organs and dyscoordination of chemokine secretion as key contributors to immune aging

Aging is characterized by progressive loss of organ and tissue function, and the immune system is no exception to that inevitable principle. Of all the age-related changes in the body, reduction of the size of, and naïve T (Tn) cell output from, the thymus occurs earliest, being prominent already before or by the time of puberty. Therefore, to preserve immunity against new infections, over much of their lives, vertebrates dominantly rely on peripheral maintenance of the Tn cell pool in the secondary lymphoid organs (SLO). However, SLO structure and function subsequently also deteriorate with aging. Several recent studies have made a convincing case that this deterioration is of major importance to the erosion of protective immunity in the last third of life. Specifically, the SLO were found to accumulate multiple degenerative changes with aging. Importantly, the results from adoptive transfer and parabiosis studies teach us that the old microenvironment is the limiting factor for protective immunity in old mice. In this review, we discuss the extent, mechanisms, and potential role of stromal cell aging in the age-related alteration of T cell homeostatic maintenance and immune function decline. We use that discussion to frame the potential strategies to correct the SLO stromal aging defects - in the context of other immune rejuvenation approaches, - to improve functional immune responses and protective immunity in older adults.

Evaluation of Associations of Growth Differentiation Factor-11, Growth Differentiation Factor-8, and Their Binding Proteins, Follistatin and Follistatin-Like Protein-3, With Measures of Skeletal Muscle Mass, Muscle Strength, and Physical Function in Older Adults

BACKGROUND

Based on studies from animal models, growth differentiation factor-11 (GDF-11) may have rejuvenating effects in humans. GDF-11 has high sequence homology with GDF-8 (also known as myostatin); follistatin and follistatin-like protein-3 (FSTL-3) are inhibitory proteins of both GDF-8 and GDF-11.

METHODS

Using highly specific liquid chromatography with tandem mass spectrometry assays for GDF-11 and GDF-8 and immunoassays for follistatin and FSTL-3, we quantified the association of these factors with muscle size, strength, and physical performance in 2 prospective cohort studies of community-dwelling older adults (Health, Aging, and Body Composition study [Health ABC] and Cardiovascular Health Study [CHS]).

RESULTS

GDF-8 levels were positively associated with thigh muscle cross-sectional area and density in Health ABC (data not available in CHS). GDF-8 levels were positively associated with lean mass (a surrogate of muscle mass) in Health ABC but not CHS, and grip strength in CHS but not Health ABC. FSTL-3 (and perhaps follistatin) was negatively associated with lean mass and had variable associations with other variables. In contrast, GDF-11 was not significantly associated with strength or performance.

CONCLUSIONS

GDF-8 and its binding proteins, follistatin and FSTL-3, may constitute a counterregulatory system (chalones) to restrain age-related loss of muscle mass and strength.

Circulating Total Extracellular Vesicles Cargo Are Associated with Age-Related Oxidative Stress and Susceptibility to Cardiovascular Diseases: Exploratory Results from Microarray Data

Aging is a risk factor for many non-communicable diseases such as cardiovascular and neurodegenerative diseases. Extracellular vesicles and particles (EVP) carry microRNAs that may play a role in age-related diseases and may induce oxidative stress. We hypothesized that aging could impact EVP miRNA and impair redox homeostasis, contributing to chronic age-related diseases. Our aims were to investigate the microRNA profiles of circulating total EVPs from aged and young adult animals and to evaluate the pro- and antioxidant machinery in circulating total EVPs. Plasma from 3- and 21-month-old male Wistar rats were collected, and total EVPs were isolated. MicroRNA isolation and microarray expression analysis were performed on EVPs to determine the predicted regulation of targeted mRNAs. Thirty-one mature microRNAs in circulating EVPs were impacted by age and were predicted to target molecules in canonical pathways directly related to cardiovascular diseases and oxidative status. Circulating total EVPs from aged rats had significantly higher NADPH oxidase levels and myeloperoxidase activity, whereas catalase activity was significantly reduced in EVPs from aged animals. Our data shows that circulating total EVP cargo-specifically microRNAs and oxidative enzymes-are involved in redox imbalance in the aging process and can potentially drive cardiovascular aging and, consequently, cardiac disease.

Evaluation of Associations of Growth Differentiation Factor-11, Growth Differentiation Factor-8, and Their Binding Proteins Follistatin and Follistatin-Like Protein-3 With Dementia and Cognition

BACKGROUND

Studies using heterochronic parabiosis discovered that circulating factors mediate brain aging in animal models.

METHODS

We assessed growth differentiation factors (GDF)-11 and GDF-8 using mass spectrometry and inhibitors follistatin and follistatin-like protein-3 (FSTL-3) with ELISA in the Cardiovascular Health Study (CHS; N = 1 506) and the Health, Aging and Body Composition (Health ABC) Study (N = 1 237). CLL-11 and beta-2 microglobulin (β2M) were measured with ELISA in a subset of 400 individuals in Health ABC. Associations were assessed with cognitive function, brain magnetic resonance imaging (MRI) findings (CHS only), and incident dementia using correlations, linear regression, and Cox proportional hazards models.

RESULTS

In CHS, levels of GDF-11, GDF-8, and follistatin were not correlated cross-sectionally with the 3MSE or DSST, brain MRI findings of white matter hyperintensity, atrophy, or small infarcts, nor were they associated with incident dementia. FSTL-3 was modestly correlated with poorer cognitive function, greater white matter hyperintensities, and atrophy on MRI, as well as with incident dementia with an adjusted hazard ratio (HR) of 1.72 (95% CI = 1.13, 2.61) per doubling of FSTL-3. FSTL-3 was not associated with cognition or dementia in Health ABC, but GDF-8 was associated with both. The adjusted HR for incident dementia was 1.50 (95% CI = 1.07, 2.10) per doubling of GDF-8.

CONCLUSIONS

Total GDF-11 level was not related to cognition or dementia in older adults. Associations of GDF-8 with cognitive outcomes in Health ABC were not expected, but consistent with animal models. Associations of FSTL-3 with cognition, brain abnormalities, and incident dementia in CHS implicate TGFβ superfamily inhibition in the pathogenesis of dementia.

Correlation of bioactive components of platelet rich plasma derived from human female adult peripheral blood and umbilical cord blood with age

Platelet-rich plasma (PRP) has gained significant attention in the field of regenerative medicine due to its potential therapeutic applications. However, few studies have reported the components, especially anti-ageing-related components, of PRP derived from umbilical cord blood (UCB). It is essential to understand the influence of age on the composition and efficacy of PRP to optimize its clinical use. The present study compared the concentrations of bioactive components in PRP from healthy female adults and UCB-derived PRP. PRP was obtained from blood samples from females in four age groups (12 per group): neonates (UCB donors) and adults aged 18-25, 26-45, and 46-65 years, respectively. The concentrations of epidermal growth factor, basic fibroblast growth factor-2 (FGF-2), insulin-like growth factor-1, platelet-derived growth factor-AA (PDGF-AA), PDGF-AB/BB, vascular endothelial growth factor A, RANTES, TIMP-1, TIMP-2, GDF11, and clusterin and activity of superoxide dismutase, catalase, and glutathione peroxidase (GPx) in the PRP samples were determined and compared among groups. Pairwise comparisons between the groups showed statistically significant differences in the concentrations of some bioactive components of PRP, such as FGF-2, PDGF-AB/BB, and clusterin, and GPx activity. UCB-derived PRP contains various active ingredients such as VEGF-A, CAT activity, and TIMP-2. Contrary to expectations, UCB-derived PRP did not show higher concentrations of the anti-ageing protein GDF11. Because UCB is a rich source of bioactive components with low immunogenicity, its use in PRP preparation is an important research direction for future studies.