Targeting senescence improves angiogenic potential of adipose-derived mesenchymal stem cells in patients with preeclampsia

Placental Senescence and the Two-Stage Model of Preeclampsia

In this review, we summarize how an increasingly stressed and aging placenta contributes to the maternal clinical signs of preeclampsia, a potentially lethal pregnancy complication. The pathophysiology of preeclampsia has been conceptualized in the two-stage model. Originally, highlighting the importance of poor placentation for early-onset preeclampsia, the revised two-stage model explains late-onset preeclampsia as well, which is often preceded by normal placentation. We discuss how cellular senescence in the placenta may fit with the framework of the revised two-stage model of preeclampsia pathophysiology and summarize potential cellular and molecular mechanisms, including effects on placental and maternal endothelial function. Cellular senescence may occur in response to inflammatory processes and oxidative, mitochondrial, or endoplasmic reticulum stress and chronic stress induce accelerated, premature placental senescence. In preeclampsia, both circulating and tissue-based senescence markers are present. We suggest that aspirin prophylaxis, commonly recommended from the first trimester onward for women at risk of preeclampsia, may affect placentation and possibly mechanisms of placental senescence, thus attenuating the risk of preeclampsia developing clinically. We propose that biomarkers of placental dysfunction and senescence may contribute to altered preventive strategies, including discontinuation of aspirin at week 24-28 depending on placenta-associated biomarker risk stratification.

Extracellular Vesicles Generated by Mesenchymal Stem Cells in Stirred Suspension Bioreactors Promote Angiogenesis in Human-Brain-Derived Endothelial Cells

Interrupted blood flow in the brain due to ischemic injuries such as ischemic stroke or traumatic brain injury results in irreversible brain damage, leading to cognitive impairment associated with inflammation, disruption of the blood-brain barrier (BBB), and cell death. Since the BBB only allows entry to a small class of drugs, many drugs used to treat ischemia in other tissues have failed in brain-related disorders. The administration of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) has shown promise in improving the functional recovery of the brain following cerebral ischemia by inducing blood vessel formation. To facilitate such a treatment approach, it is necessary to develop bioprocesses that can produce therapeutically relevant MSC-EVs in a reproducible and scalable manner. This study evaluated the feasibility of using stirred suspension bioreactors (SSBs) to scale-up the serum-free production of pro-angiogenic MSC-EVs under clinically relevant physioxic conditions. It was found that MSCs grown in SSBs generated EVs that stimulated angiogenesis in cerebral microvascular endothelial cells, supporting the use of SSBs to produce MSC-EVs for application in cerebral ischemia. These properties were impaired at higher cell confluency, outlining the importance of considering the time of harvest when developing bioprocesses to manufacture EV populations.

Single cell RNA-sequencing reveals the cellular senescence of placental mesenchymal stem/stromal cell in preeclampsia

INTRODUCTION

Preeclampsia (PE) is a severe obstetric complication closely associated with placental dysfunction. Placental mesenchymal stem/stromal cells (PMSCs) modulate placental development while PE PMSCs are excessively senescent to disturb placental function. Nevertheless, the senescence mechanism of PE PMSCs remains unclear.

METHODS

PE-related single-cell RNA sequencing datasets (GSE173193), data of chip detection (GSE99007) and bulk transcriptome RNA sequencing datasets (GSE75010) were extracted from the GEO database. Firstly, the functional enrichment analyses of the differentially expressed genes (DEGs) in PMSCs were conducted. Then, the clusters of PE PMSCs were distinguished according to the expressions of senescence-related genes (SRGs) by consensus clustering analysis. Cell cycle analysis, senescence β-galactosidase, Transwell, and tube formation were conducted. Next, the expressions of the senescence-associated secretory phenotype (SASPs) were displayed. The characteristic genes of PE were screened by the least absolute shrinkage and selection operator analysis. CTSZ was suppressed in PMSCs and the cellular senescence levels were evaluated.

RESULTS

In this study, The DEGs in PMSCs were closely associated with cellular senescence. The score of SRGs was significantly higher and most of the SASPs were abnormally expressed in the senescent group. Seven characteristic genes of PE were identified, thereinto, CTSZ reduction may accelerate the senescence in PMSCs in vitro.

DISCUSSION

Combined with bioinformatic analysis and lab experiments, our study emphatically revealed the abnormal cellular senescence in PE PMSCs, in which CTSZ, one of the PE characteristic genes, regulated the cellular senescence levels in PMSCs. These findings might help to deepen the understanding of the senescence mechanism of PMSCs in PE.

Human Rotator Cuff Tears Reveal an Age-Dependent Increase in Markers of Cellular Senescence and Selective Removal of Senescent Cells With Dasatinib + Quercetin Increases Genetic Expression of COL1A1 In Vitro

PURPOSE

To quantify cellular senescence in supraspinatus tendon and subacromial bursa of humans with rotator cuff tears and to investigate the in vitro efficacy of the senolytic dasatinib + quercetin (D+Q) to eliminate senescent cells and alter tenogenic differentiation.

METHODS

Tissue was harvested from 41 patients (mean age, 62 years) undergoing arthroscopic rotator cuff repairs. In part 1 (n = 35), senescence was quantified using immunohistochemistry and gene expression for senescent cell markers (p16 and p21) and the senescence-associated secretory phenotype (SASP) (interleukin [IL] 6, IL-8, matrix metalloproteinase [MMP] 3, monocyte chemoattractant protein [MCP] 1). Senescence was compared between patients <60 and ≥60 years old. In part 2 (n = 6) , an in vitro model of rotator cuff tears was treated with D+Q or control. D+Q, a chemotherapeutic and plant flavanol, respectively, kill senescent cells. Gene expression analysis assessed the ability of D+Q to kill senescent cells and alter markers of tenogenic differentiation.

RESULTS

Part 1 revealed an age-dependent significant increase in the relative expression of p21, IL-6, and IL-8 in tendon and p21, p16, IL-6, IL-8, and MMP-3 in bursa (P < .05). A significant increase was seen in immunohistochemical staining of bursa p21 (P = .028). In part 2, D+Q significantly decreased expression of p21, IL-6, and IL-8 in tendon and p21 and IL-8 in bursa (P < .05). Enzyme-linked immunosorbent assay analysis showed decreased release of the SASP (IL-6, MMP-3, MCP-1; P = .002, P = .024, P < .001, respectively). Tendon (P = .022) and bursa (P = .027) treated with D+Q increased the expression of COL1A1.

CONCLUSIONS

While there was an age-dependent increase in markers of cellular senescence, this relationship was not consistently seen across all markers and tissues. Dasatinib + quercetin had moderate efficacy in decreasing senescence in these tissues and increasing COL1A1 expression.

CLINICAL RELEVANCE

This study reveals that cellular senescence may be a therapeutic target to alter the biological aging of rotator cuffs and identifies D+Q as a potential therapy.

Yearning for machine learning: applications for the classification and characterisation of senescence

Senescence is a widely appreciated tumour suppressive mechanism, which acts as a barrier to cancer development by arresting cell cycle progression in response to harmful stimuli. However, senescent cell accumulation becomes deleterious in aging and contributes to a wide range of age-related pathologies. Furthermore, senescence has beneficial roles and is associated with a growing list of normal physiological processes including wound healing and embryonic development. Therefore, the biological role of senescent cells has become increasingly nuanced and complex. The emergence of sophisticated, next-generation profiling technologies, such as single-cell RNA sequencing, has accelerated our understanding of the heterogeneity of senescence, with distinct final cell states emerging within models as well as between cell types and tissues. In order to explore data sets of increasing size and complexity, the senescence field has begun to employ machine learning (ML) methodologies to probe these intricacies. Most notably, ML has been used to aid the classification of cells as senescent, as well as to characterise the final senescence phenotypes. Here, we provide a background to the principles of ML tasks, as well as some of the most commonly used methodologies from both traditional and deep ML. We focus on the application of these within the context of senescence research, by addressing the utility of ML for the analysis of data from different laboratory technologies (microscopy, transcriptomics, proteomics, methylomics), as well as the potential within senolytic drug discovery. Together, we aim to highlight both the progress and potential for the application of ML within senescence research.

Impact of Aging and Cellular Senescence in the Pathophysiology of Preeclampsia

The incidence of hypertensive disorders of pregnancy is increasing, which may be due to several factors, including an increased age at pregnancy and more comorbid health conditions during reproductive years. Preeclampsia, the most severe hypertensive disorder of pregnancy, has been associated with an increased risk of future disease, including cardiovascular and kidney diseases. Cellular senescence, the process of cell cycle arrest in response to many physiologic and maladaptive stimuli, may play an important role in the pathogenesis of preeclampsia and provide a mechanistic link to future disease. In this article, we will discuss the pathophysiology of preeclampsia, the many mechanisms of cellular senescence, evidence for the involvement of senescence in the development of preeclampsia, as well as evidence that cellular senescence may link preeclampsia to the risk of future disease. Lastly, we will explore how a better understanding of the role of cellular senescence in preeclampsia may lead to therapeutic trials. © 2023 American Physiological Society. Compr Physiol 13:5077-5114, 2023.

Bone Marrow Microenvironment Involvement in t-MN: Focus on Mesenchymal Stem Cells

Therapy-related myeloid neoplasms (t-MN) are a late complication of cytotoxic therapy (CT) used in the treatment of both malignant and non-malignant diseases. Historically, t-MN has been considered to be a direct consequence of DNA damage induced in normal hematopoietic stem or progenitor cells (HSPC) by CT. However, we now know that treatment-induced mutations in HSC are not the only players involved in t-MN development, but additional factors may contribute to the onset of t-MN. One of the known drivers involved in this field is the bone marrow microenvironment (BMM) and, in particular, bone marrow mesenchymal stem cells (BM-MSC), whose role in t-MN pathogenesis is the topic of this mini-review. BM-MSCs, physiologically, support HSC maintenance, self-renewal, and differentiation through hematopoietic-stromal interactions and the production of cytokines. In addition, BM-MSCs maintain the stability of the BM immune microenvironment and reduce the damage caused to HSC by stress stimuli. In the t-MN context, chemo/radiotherapy may induce damage to the BM-MSC and likewise alter BM-MSC functions by promoting pro-inflammatory response, clonal selection and/or the production of factors that may favor malignant hematopoiesis. Over the last decade, it has been shown that BM-MSC isolated from patients with de novo and therapy-related MN exhibit decreased proliferative and clonogenic capacity, altered morphology, increased senescence, defective osteogenic differentiation potential, impaired immune-regulatory properties, and reduced ability to support HSC growth and differentiation, as compared to normal BM-MSC. Although the understanding of the genetic and gene expression profile associated with ex vivo-expanded t-MN-MSCs remains limited and debatable, its potential role in prognostic and therapeutic terms is acting as a flywheel of attraction for many researchers.

Methylglyoxal Impairs the Pro-Angiogenic Ability of Mouse Adipose-Derived Stem Cells (mADSCs) via a Senescence-Associated Mechanism

Adipose-derived stem cells (ADSCs) play a crucial role in angiogenesis and repair of damaged tissues. However, in pathological conditions including diabetes, ADSC function is compromised. This work aims at evaluating the effect of Methylglyoxal (MGO), a product of chronic hyperglycemia, on mouse ADSCs' (mADSCs) pro-angiogenic function and the molecular mediators involved. The mADSCs were isolated from C57bl6 mice. MGO-adducts and p-p38 MAPK protein levels were evaluated by Western Blot. Human retinal endothelial cell (hREC) migration was analyzed by transwell assays. Gene expression was measured by qRT-PCR, and SA-βGal activity by cytofluorimetry. Soluble factor release was evaluated by multiplex assay. MGO treatment does not impair mADSC viability and induces MGO-adduct accumulation. hREC migration is reduced in response to both MGO-treated mADSCs and conditioned media from MGO-treated mADSCs, compared to untreated cells. This is associated with an increase of SA-βGal activity, SASP factor release and p53 and p21 expression, together with a VEGF- and PDGF-reduced release from MGO-treated mADSCs and a reduced p38-MAPK activation in hRECs. The MGO-induced impairment of mADSC function is reverted by senolytics. In conclusion, MGO impairs mADSCs' pro-angiogenic function through the induction of a senescent phenotype, associated with the reduced secretion of growth factors crucial for hREC migration.

Stress-induced senescence in mesenchymal stem cells: Triggers, hallmarks, and current rejuvenation approaches

Mesenchymal stem cells (MSCs) have emerged as promising cell-based therapies in the treatment of degenerative and inflammatory conditions. However, despite accumulating evidence of the breadth of MSC functional potency, their broad clinical translation is hampered by inconsistencies in therapeutic efficacy, which is at least partly due to the phenotypic and functional heterogeneity of MSC populations as they progress towards senescence in vitro. MSC senescence, a natural response to aging and stress, gives rise to altered cellular responses and functional decline. This review describes the key regenerative properties of MSCs; summarises the main triggers, mechanisms, and consequences of MSC senescence; and discusses current cellular and extracellular strategies to delay the onset or progression of senescence, or to rejuvenate biological functions lost to senescence.

Heat shock proteins and cellular senescence in humans: A systematic review

Cellular senescence (CS) is a permanent arrest of cell growth and exit of the cell cycle. It is an important tumor suppression mechanism and has a key role in wound healing, tissue regeneration, and prevention of tissue fibrosis. Despite the short-term benefits of CS, accumulation of senescent cells has deleterious effects and is associated with several pathological age-related phenotypes. As Heat Shock Proteins (HSP) are associated with cyto-protection, their role in longevity and CS became a research interest. However, an overview of the relationship between HSP and CS in humans still lacks in the literature. To provide an overview of the current state of the literature, this systematic review focused on the role of HSP in the development of CS in humans. PubMed, Web of Science and Embase were systematically screened for studies on the relationship between HSP and CS in humans. A total of 14 articles were eligible for inclusion. The heterogeneity and lack of numerical reporting of outcomes obstructed the conduction of a meta-analysis. The results consistently show that HSP depletion results in increased CS, while overexpression of HSP decreases CS, whether in cancer, fibroblasts, or stem cell lines. This systematic review summarized the literature on the prospective role of HSP in the development of CS in humans.

Senescent Cells: A Therapeutic Target in Cardiovascular Diseases

Senescent cell accumulation has been observed in age-associated diseases including cardiovascular diseases. Senescent cells lack proliferative capacity and secrete senescence-associated secretory phenotype (SASP) factors that may cause or worsen many cardiovascular diseases. Therapies targeting senescent cells, especially senolytic drugs that selectively induce senescent cell removal, have been shown to delay, prevent, alleviate, or treat multiple age-associated diseases in preclinical models. Some senolytic clinical trials have already been completed or are underway for a number of diseases and geriatric syndromes. Understanding how cellular senescence affects the various cell types in the cardiovascular system, such as endothelial cells, vascular smooth muscle cells, fibroblasts, immune cells, progenitor cells, and cardiomyocytes, is important to facilitate translation of senotherapeutics into clinical interventions. This review highlights: (1) the characteristics of senescent cells and their involvement in cardiovascular diseases, focusing on the aforementioned cardiovascular cell types, (2) evidence about senolytic drugs and other senotherapeutics, and (3) the future path and clinical potential of senotherapeutics for cardiovascular diseases.

Dietary supplements and vascular function in hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy are complications that can lead to maternal and infant mortality and morbidity. Hypertensive disorders of pregnancy are generally defined as hypertension and may be accompanied by other end organ damages including proteinuria, maternal organ disturbances including renal insufficiency, neurological complications, thrombocytopenia, impaired liver function, or uteroplacental dysfunction such as fetal growth restriction and stillbirth. Although the causes of these hypertensive disorders of pregnancy are multifactorial and elusive, they seem to share some common vascular-related mechanisms, including diseased spiral arteries, placental ischemia, and endothelial dysfunction. Recently, preeclampsia is being considered as a vascular disorder. Unfortunately, due to the complex etiology of preeclampsia and safety concerns on drug usage during pregnancy, there is still no effective pharmacological treatments available for preeclampsia yet. An emerging area of interest in this research field is the potential beneficial effects of dietary intervention on reducing the risk of preeclampsia. Recent studies have been focused on the association between deficiencies or excesses of some nutrients and complications during pregnancy, fetal growth and development, and later risk of cardiovascular and metabolic diseases in the offspring. In this review, we discuss the involvement of placental vascular dysfunction in preeclampsia. We summarize the current understanding of the association between abnormal placentation and preeclampsia in a vascular perspective. Finally, we evaluate several studied dietary supplementations to prevent and reduce the risk of preeclampsia, targeting placental vascular development and function, leading to improved pregnancy and postnatal outcomes.

Markers of Cardiovascular Risk Associated with Pregnancy

PURPOSE OF REVIEW

The purpose of the review is to summarize the unique cardiovascular disease (CVD) risk factors encountered during pregnancy and to provide the reader with a framework for acquiring a comprehensive obstetric history during the cardiovascular (CV) assessment of women.

RECENT FINDINGS

Individuals with a history of pregnancies complicated by hypertensive disorders of pregnancy (HDP), gestational diabetes (GDM), preterm delivery, low birth weight, and fetal growth restriction during pregnancy are at a higher risk of developing short- and long-term CV complications compared to those without adverse pregnancy outcomes (APOs). Women with a history of APOs can be at increased risk of CVD even after achieving normoglycemia and normal blood pressure control postpartum. Risk assessment and stratification in women must account for these APOs as recommended by the 2019 American College of Cardiology (ACC)/American Heart Association (AHA) guideline on the primary prevention of CVD. Early recognition, monitoring, and treatment of APOs are key to limiting CVD complications late in maternal life. Recognition of APOs as female-specific cardiovascular risk factors is critical for risk stratification for women and birthing persons. Further research is needed to understand the complex interplay between genetics, environmental, behavioral, and maternal vascular health, and the association between APOs and CVD risk.

Senotherapeutics for mesenchymal stem cell senescence and rejuvenation

Mesenchymal stem cells (MSCs) are susceptible to replicative senescence and senescence-associated functional decline, which hampers their use in regenerative medicine. Senotherapeutics are drugs that target cellular senescence through senolytic and senomorphic functions to induce apoptosis and suppress chronic inflammation caused by the senescence-associated secreted phenotype (SASP), respectively. Therefore, senotherapeutics could delay aging-associated degeneration. They could also be used to eliminate senescent MSCs during in vitro expansion or bioprocessing for transplantation. In this review, we discuss the role of senotherapeutics in MSC senescence, rejuvenation, and transplantation, with examples of some tested compounds in vitro. The prospects, challenges, and the way forward in clinical applications of senotherapeutics in cell-based therapeutics are also discussed.

Aging of mesenchymal stem cell: machinery, markers, and strategies of fighting

Human mesenchymal stem cells (MSCs) are primary multipotent cells capable of differentiating into osteocytes, chondrocytes, and adipocytes when stimulated under appropriate conditions. The role of MSCs in tissue homeostasis, aging-related diseases, and cellular therapy is clinically suggested. As aging is a universal problem that has large socioeconomic effects, an improved understanding of the concepts of aging can direct public policies that reduce its adverse impacts on the healthcare system and humanity. Several studies of aging have been carried out over several years to understand the phenomenon and different factors affecting human aging. A reduced ability of adult stem cell populations to reproduce and regenerate is one of the main  contributors to the human aging process. In this context, MSCs senescence is a major challenge in front of cellular therapy advancement. Many factors, ranging from genetic and metabolic pathways to extrinsic factors through various cellular signaling pathways, are involved in regulating the mechanism of MSC senescence. To better understand and reverse cellular senescence, this review highlights the underlying mechanisms and signs of MSC cellular senescence, and discusses the strategies to combat aging and cellular senescence.

Abnormal cerebral microvascular perfusion and reactivity in female offspring of reduced uterine perfusion pressure (RUPP) mice model

Children born from women with preeclampsia have alterations in cerebral neurovascular development and a high risk for developing cognitive alterations. Because cerebral blood vessels are critical components in cerebrovascular development, we evaluated the brain microvascular perfusion and microvascular reactivity (exposed to external stimuli of warm and cold) in pups born to preeclampsia-like syndrome based on the reduction of uterine perfusion (RUPP). Also, we evaluate the angiogenic proteomic profile in those brains. Pregnant mice showed a reduction in uterine flow after RUPP surgery (-40 to 50%) associated with unfavorable perinatal results compared to sham mice. Furthermore, offspring of the RUPP mice exhibited reduced brain microvascular perfusion at postnatal day 5 (P5) compared with offspring from sham mice. This reduction was preferentially observed in females. Also, brain microvascular reactivity to external stimuli (warm and cold) was reduced in pups of RUPP mice. Furthermore, a differential expression of the angiogenic profile associated with inflammation, extrinsic apoptotic, cancer, and cellular senescence processes as the primary signaling impaired process was found in the brains of RUPP-offspring. Then, offspring (P5) from preeclampsia-like syndrome exhibit impaired brain perfusion and microvascular reactivity, particularly in female mice, associated with differential expression of angiogenic proteins in the brain tissue.

Cellular senescence and senolytics: the path to the clinic

Interlinked and fundamental aging processes appear to be a root-cause contributor to many disorders and diseases. One such process is cellular senescence, which entails a state of cell cycle arrest in response to damaging stimuli. Senescent cells can arise throughout the lifespan and, if persistent, can have deleterious effects on tissue function due to the many proteins they secrete. In preclinical models, interventions targeting those senescent cells that are persistent and cause tissue damage have been shown to delay, prevent or alleviate multiple disorders. In line with this, the discovery of small-molecule senolytic drugs that selectively clear senescent cells has led to promising strategies for preventing or treating multiple diseases and age-related conditions in humans. In this Review, we outline the rationale for senescent cells as a therapeutic target for disorders across the lifespan and discuss the most promising strategies-including recent and ongoing clinical trials-for translating small-molecule senolytics and other senescence-targeting interventions into clinical use.

Mettl14-driven senescence-associated secretory phenotype facilitates somatic cell reprogramming

The METTL3-METTL14 complex, the “writer” of N⁶-methyladenosine (m⁶A), plays an important role in many biological processes. Previous studies have shown that Mettl3 overexpression can increase the level of m⁶A and promote somatic cell reprogramming. Here, we demonstrate that Mettl14, another component of the methyltransferase complex, can significantly enhance the generation of induced pluripotent stem cells (iPSCs) in an m⁶A-independent manner. In cooperation with Oct4, Sox2, Klf4, and c-Myc, overexpressed Mettl14 transiently promoted senescence-associated secretory phenotype (SASP) gene expression in non-reprogrammed cells in the late stage of reprogramming. Subsequently, we demonstrated that interleukin-6 (IL-6), a component of the SASP, significantly enhanced somatic cell reprogramming. In contrast, blocking the SASP using a senolytic agent or a nuclear factor κB (NF-κB) inhibitor impaired the effect of Mettl14 on reprogramming. Our results highlight the m⁶A-independent function of Mettl14 in reprogramming and provide new insight into the interplay between senescence and reprogramming in vitro.

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Mettl14 can facilitate somatic cell reprogramming in an m⁶A-independent manner

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Mettl14 transcriptionally drives the senescence-associated secretory phenotype (SASP)

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Mettl14-driven SASPs are mainly secreted from non-reprogramming cells

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Blocking of SASP impairs the effect of Mettl14 on reprogramming

The pathological and therapeutic roles of mesenchymal stem cells in preeclampsia

Mesenchymal stem cells (MSCs) have made progress in the treatment of ischemic and inflammatory diseases. Preeclampsia (PE) is characterized by placenta ischemic and inflammatory injury. Our paper summarized the new role of MSCs in PE pathology and its potency in PE therapy and analyzed its current limitations. Intravenously administered MSCs dominantly distributed in perinatal tissues. There may be additional advantages to using MSCs-based therapies for reproductive disorders. It will provide new ideas for future research in this field.

Potential pre-activation strategies for improving therapeutic efficacy of mesenchymal stem cells: current status and future prospects

Mesenchymal stem cell (MSC)-based therapy has been considered as a promising approach targeting a variety of intractable diseases due to remarkable multiple effect of MSCs, such as multilineage differentiation, immunomodulatory property, and pro-regenerative capacity. However, poor engraftment, low survival rate of transplanted MSC, and impaired donor-MSC potency under host age/disease result in unsatisfactory therapeutic outcomes. Enhancement strategies, including genetic manipulation, pre-activation, and modification of culture method, have been investigated to generate highly functional MSC, and approaches for MSC pre-activation are highlighted. In this review, we summarized the current approaches of MSC pre-activation and further classified, analysed the scientific principles and main characteristics of these manipulations, and described the pros and cons of individual pre-activation strategies. We also discuss the specialized tactics to solve the challenges in this promising field so that it improves MSC therapeutic functions to serve patients better.

Orally-active, clinically-translatable senolytics restore α-Klotho in mice and humans

BACKGROUND

α-Klotho is a geroprotective protein that can attenuate or alleviate deleterious changes with ageing and disease. Declines in α-Klotho play a role in the pathophysiology of multiple diseases and age-related phenotypes. Pre-clinical evidence suggests that boosting α-Klotho holds therapeutic potential. However, readily clinically-translatable, practical strategies for increasing α-Klotho are not at hand. Here, we report that orally-active, clinically-translatable senolytics can increase α-Klotho in mice and humans.

METHODS

We examined α-Klotho expression in three different human primary cell types co-cultured with conditioned medium (CM) from senescent or non-senescent cells with or without neutralizing antibodies. We assessed α-Klotho expression in aged, obese, and senescent cell-transplanted mice treated with vehicle or senolytics. We assayed urinary α-Klotho in patients with idiopathic pulmonary fibrosis (IPF) who were treated with the senolytic drug combination, Dasatinib plus Quercetin (D+Q).

FINDINGS

We found exposure to the senescent cell secretome reduces α-Klotho in multiple nonsenescent human cell types. This was partially prevented by neutralizing antibodies against the senescence-associated secretory phenotype (SASP) factors, activin A and Interleukin 1α (IL-1α). Consistent with senescent cells' being a cause of decreased α-Klotho, transplanting senescent cells into younger mice reduced brain and urine α-Klotho. Selectively removing senescent cells genetically or pharmacologically increased α-Klotho in urine, kidney, and brain of mice with increased senescent cell burden, including naturally-aged, diet-induced obese (DIO), or senescent cell-transplanted mice. D+Q increased α-Klotho in urine of patients with IPF, a disease linked to cellular senescence.

INTERPRETATION

Senescent cells cause reduced α-Klotho, partially due to their production of activin A and IL-1α. Targeting senescent cells boosts α-Klotho in mice and humans. Thus, clearing senescent cells restores α-Klotho, potentially opening a novel, translationally-feasible avenue for developing orally-active small molecule, α-Klotho-enhancing clinical interventions. Furthermore, urinary α-Klotho may prove to be a useful test for following treatments in senolytic clinical trials.

FUNDING

This work was supported by National Institute of Health grants AG013925 (J.L.K.), AG062413 (J.L.K., S.K.), AG044271 (N.M.), AG013319 (N.M.), and the Translational Geroscience Network (AG061456: J.L.K., T.T., N.M., S.B.K., S.K.), Robert and Arlene Kogod (J.L.K.), the Connor Group (J.L.K.), Robert J. and Theresa W. Ryan (J.L.K.), and the Noaber Foundation (J.L.K.). The previous IPF clinical trial was supported by the Claude D. Pepper Older Americans Independence Centers at WFSM (AG021332: J.N.J., S.B.K.), UTHSCA (AG044271: A.M.N.), and the Translational Geroscience Network.

Effects of obesity on reparative function of human adipose tissue-derived mesenchymal stem cells on ischemic murine kidneys

Introduction:

Obesity is a health burden that impairs cellular processes. Mesenchymal stem/stromal cells (MSCs) are endowed with reparative properties and can ameliorate renal injury. Obesity impairs human MSC function in-vitro, but its effect on their in-vivo reparative potency remains unknown.

Subjects and Methods:

Abdominal adipose tissue-derived MSC were harvested from patients without (‘lean’) or with obesity (‘obese’) (body mass index<30 or ≥30kg/m², respectively) during kidney donation or bariatric surgery, respectively. MSC (5x10⁵/200μL) or vehicle were then injected into 129S1 mice 2 weeks after renal artery stenosis (RAS) or sham surgery (n=8/group). Two weeks later, mice underwent magnetic resonance imaging to assess renal perfusion and oxygenation in-vivo, and kidneys then harvested for ex-vivo studies.

Results:

Similar numbers of lean and obese-MSCs engrafted in stenotic mouse kidneys. Vehicle-treated RAS mice had reduced stenotic-kidney cortical and medullary perfusion and oxygenation. Lean (but not obese) MSC normalized ischemic kidney cortical perfusion, whereas both effectively mitigated renal hypoxia. Serum creatinine and blood pressure were elevated in RAS mice and lowered only by lean-MSC. Both types of MSCs alleviated stenotic-kidney fibrosis, but lean-MSC more effectively than obese-MSC. MSC senescence-associated beta-gal activity, and gene expression of p16, p21, and vascular endothelial growth factor correlated with recipient kidney perfusion and tissue injury, linking MSC characteristics with their in-vivo reparative capacity.

Discussion:

Human obesity impairs the reparative properties of adipose-tissue-derived MSCs, possibly by inducing cellular senescence. Dysfunction and senescence of the endogenous MSC repair system in patients with obesity may warrant targeting interventions to restore MSC vitality.

Role of senescence in the chronic health consequences of COVID-19

While the full impact of COVID-19 is not yet clear, early studies have indicated that upwards of 10% of patients experience COVID-19 symptoms longer than 3 weeks, known as Long-Hauler's Syndrome or PACS (postacute sequelae of SARS-CoV-2 infection). There is little known about risk factors or predictors of susceptibility for Long-Hauler's Syndrome, but older adults are at greater risk for severe outcomes and mortality from COVID-19. The pillars of aging (including cellular senescence, telomere dysfunction, impaired proteostasis, mitochondrial dysfunction, deregulated nutrient sensing, genomic instability, progenitor cell exhaustion, altered intercellular communication, and epigenetic alterations) that contribute to age-related dysfunction and chronic diseases (the "Geroscience Hypothesis") may interfere with defenses against viral infection and consequences of these infections. Heightening of the low-grade inflammation that is associated with aging may generate an exaggerated response to an acute COVID-19 infection. Innate immune system dysfunction that leads to decreased senescent cell removal and/or increased senescent cell formation could contribute to accumulation of senescent cells with both aging and viral infections. These processes may contribute to increased risk for long-term COVID-19 sequelae in older or chronically ill patients. Hence, senolytics and other geroscience interventions that may prolong healthspan and alleviate chronic diseases and multimorbidity linked to fundamental aging processes might be an option for delaying, preventing, or alleviating Long-Hauler's Syndrome.

Pregnancy and Reproductive Risk Factors for Cardiovascular Disease in Women

Beyond conventional risk factors for cardiovascular disease, women face an additional burden of sex-specific risk factors. Key stages of a woman's reproductive history may influence or reveal short- and long-term cardiometabolic and cardiovascular trajectories. Early and late menarche, polycystic ovary syndrome, infertility, adverse pregnancy outcomes (eg, hypertensive disorders of pregnancy, gestational diabetes, preterm delivery, and intrauterine growth restriction), and absence of breastfeeding are all associated with increased future cardiovascular disease risk. The menopause transition additionally represents a period of accelerated cardiovascular disease risk, with timing (eg, premature menopause), mechanism, and symptoms of menopause, as well as treatment of menopause symptoms, each contributing to this risk. Differences in conventional cardiovascular disease risk factors appear to explain some, but not all, of the observed associations between reproductive history and later-life cardiovascular disease; further research is needed to elucidate hormonal effects and unique sex-specific disease mechanisms. A history of reproductive risk factors represents an opportunity for comprehensive risk factor screening, refinement of cardiovascular disease risk assessment, and implementation of primordial and primary prevention to optimize long-term cardiometabolic health in women.

Hypertension in Pregnancy: Diagnosis, Blood Pressure Goals, and Pharmacotherapy: A Scientific Statement From the American Heart Association

Hypertensive disorders of pregnancy (HDP) remain one of the major causes of pregnancy-related maternal and fetal morbidity and mortality worldwide. Affected women are also at increased risk for cardiovascular disease later in life, independently of traditional cardiovascular disease risks. Despite the immediate and long-term cardiovascular disease risks, recommendations for diagnosis and treatment of HDP in the United States have changed little, if at all, over past decades, unlike hypertension guidelines for the general population. The reasons for this approach include the question of benefit from normalization of blood pressure treatment for pregnant women, coupled with theoretical concerns for fetal well-being from a reduction in utero-placental perfusion and in utero exposure to antihypertensive medication. This report is based on a review of current literature and includes normal physiological changes in pregnancy that may affect clinical presentation of HDP; HDP epidemiology and the immediate and long-term sequelae of HDP; the pathophysiology of preeclampsia, an HDP commonly associated with proteinuria and increasingly recognized as a heterogeneous disease with different clinical phenotypes and likely distinct pathological mechanisms; a critical overview of current national and international HDP guidelines; emerging evidence that reducing blood pressure treatment goals in pregnancy may reduce maternal severe hypertension without increasing the risk of pregnancy loss, high-level neonatal care, or overall maternal complications; and the increasingly recognized morbidity associated with postpartum hypertension/preeclampsia. Finally, we discuss the future of research in the field and the pressing need to study socioeconomic and biological factors that may contribute to racial and ethnic maternal health care disparities.

A senescence stress secretome is a hallmark of therapy-related myeloid neoplasm stromal tissue occurring soon after cytotoxic exposure

Therapy-related myeloid neoplasm (tMN) is considered a direct consequence of DNA damage in hematopoietic stem cells. Despite increasing recognition that altered stroma can also drive leukemogenesis, the functional biology of the tMN microenvironment remains unknown. We performed multiomic (transcriptome, DNA damage response, cytokine secretome and functional profiling) characterization of bone marrow stromal cells from tMN patients. Critically, we also compared (i) patients with myeloid neoplasm and another cancer but without cytotoxic exposure, (ii) typical primary myeloid neoplasm, and (iii) age-matched controls to decipher the microenvironmental changes induced by cytotoxics vs. neoplasia. Strikingly, tMN exhibited a profoundly senescent phenotype with induction of CDKN1A and β-Galactosidase, defective phenotype, and proliferation. Moreover, tMN stroma showed delayed DNA repair and defective adipogenesis. Despite their dormant state, tMN stromal cells were metabolically highly active with a switch toward glycolysis and secreted multiple pro-inflammatory cytokines indicative of a senescent-secretory phenotype that inhibited adipogenesis. Critically, senolytics not only eliminated dormant cells, but also restored adipogenesis. Finally, sequential patient sampling showed senescence phenotypes are induced within months of cytotoxic exposure, well prior to the onset of secondary cancer. Our data underscores a role of senescence in the pathogenesis of tMN and provide a valuable resource for future therapeutics.

Tumorigenic Aspects of MSC Senescence-Implication in Cancer Development and Therapy

As an organism ages, many physiological processes change, including the immune system. This process, called immunosenescence, characterized by abnormal activation and imbalance of innate and adaptive immunity, leads to a state of chronic low-grade systemic inflammation, termed inflammaging. Aging and inflammaging are considered to be the root of many diseases of the elderly, as infections, autoimmune and chronic inflammatory diseases, degenerative diseases, and cancer. The role of mesenchymal stromal/stem cells (MSCs) in the inflammaging process and the age-related diseases is not completely established, although numerous features of aging MSCs, including altered immunomodulatory properties, impeded MSC niche supporting functions, and senescent MSC secretory repertoire are consistent with inflammaging development. Although senescence has its physiological function and can represent a mechanism of tumor prevention, in most cases it eventually transforms into a deleterious (para-)inflammatory process that promotes tumor growth. In this review we are going through current literature, trying to explore the role of senescent MSCs in making and/or sustaining a microenvironment permissive to tumor development and to analyze the therapeutic options that could target this process.

Age and Sex: Impact on adipose tissue metabolism and inflammation

Age associated chronic inflammation is a major contributor to diseases with advancing age. Adipose tissue function is at the nexus of processes contributing to age-related metabolic disease and mediating longevity. Hormonal fluctuations in aging potentially regulate age-associated visceral adiposity and metabolic dysfunction. Visceral adiposity in aging is linked to aberrant adipogenesis, insulin resistance, lipotoxicity and altered adipokine secretion. Age-related inflammatory phenomena depict sex differences in macrophage polarization, changes in T and B cell numbers, and types of dendritic cells. Sex differences are also observed in adipose tissue remodeling and cellular senescence suggesting a role for sex steroid hormones in the regulation of the adipose tissue microenvironment. It is crucial to investigate sex differences in aging clinical outcomes to identify and better understand physiology in at-risk individuals. Early interventions aimed at targets involved in adipose tissue adipogenesis, remodeling and inflammation in aging could facilitate a profound impact on health span and overcome age-related functional decline.

TNF-α and IFN-γ Participate in Improving the Immunoregulatory Capacity of Mesenchymal Stem/Stromal Cells: Importance of Cell-Cell Contact and Extracellular Vesicles

Mesenchymal stem/stromal cells (MSCs) have an immunoregulatory capacity and have been used in different clinical protocols requiring control of the immune response. However, variable results have been obtained, mainly due to the effect of the microenvironment on the induction, increase, and maintenance of MSC immunoregulatory mechanisms. In addition, the importance of cell–cell contact for MSCs to efficiently modulate the immune response has recently been highlighted. Because these interactions would be difficult to achieve in the physiological context, the release of extracellular vesicles (EVs) and their participation as intermediaries of communication between MSCs and immune cells becomes relevant. Therefore, this article focuses on analyzing immunoregulatory mechanisms mediated by cell contact, highlighting the importance of intercellular adhesion molecule-1 (ICAM-1) and the participation of EVs. Moreover, the effects of tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), the main cytokines involved in MSC activation, are examined. These cytokines, when used at the appropriate concentrations and times, would promote increases in the expression of immunoregulatory molecules in the cell and allow the acquisition of EVs enriched with these molecules. The establishment of certain in vitro activation guidelines will facilitate the design of conditioning protocols to obtain functional MSCs or EVs in different pathophysiological conditions.

Epigenetic and senescence markers indicate an accelerated ageing-like state in women with preeclamptic pregnancies

Background

Preeclampsia is a pregnancy-specific hypertensive disorder characterized by proteinuria and/or multisystem involvement. Disease-specific therapy has yet to be developed due to the lack of understanding of underlying mechanism(s). We postulate that accelerated ageing in general, and particularly cellular senescence, play a role in its pathophysiology.

Methods

We compared women with preeclampsia vs. normotensive pregnancies with respect to epigenetic markers of ageing and markers of senescence in tissues/organs affected by preeclampsia (blood, urine, adipose tissue, and kidney).

Findings

We demonstrate that preeclamptic compared to normotensive pregnant women: (i) undergo accelerated epigenetic ageing during pregnancy, as demonstrated by an “epigenetic clock”; (ii) exhibit higher levels/expression of senescence-associated secretory phenotype factors in blood and adipose tissue; (iii) display increased expression of p16^INK4A in adipose tissue and renal sections, and (iv) demonstrate decreased levels of urinary α-Klotho (an anti-ageing protein) at the time of delivery. Finally, we provide data indicating that pre-treatment with dasatinib, a senolytic agent, rescues the angiogenic potential of mesenchymal stem cells (MSC) obtained from preeclamptic pregnancies, and promotes angiogenesis, even under pro-inflammatory conditions.

Interpretation

Taken together, our results identify senescence as one of the mechanisms underpinning the pathophysiology of preeclampsia. Therapeutic strategies that target senescent cells may offer novel mechanism-based treatments for preeclampsia.

Funding

This work was supported by NIH grants, R01 HL136348, R37 AG013925, P01 AG062413, R01 DK11916, generous gifts from the Connor Fund, Robert J. and Theresa W. Ryan and from The George G. Beasley family, the Noaber Foundation, and the Henry and Emma Meyer Professorship in Molecular Genetics.

DOT1L modulates the senescence-associated secretory phenotype through epigenetic regulation of IL1A

Oncogene-induced senescence (OIS) is a stable cell cycle arrest that occurs in normal cells upon oncogene activation. Cells undergoing OIS express a wide variety of secreted factors that affect the senescent microenvironment termed the senescence-associated secretory phenotype (SASP), which is beneficial or detrimental in a context-dependent manner. OIS cells are also characterized by marked epigenetic changes. We globally assessed histone modifications of OIS cells and discovered an increase in the active histone marks H3K79me2/3. The H3K79 methyltransferase disruptor of telomeric silencing 1-like (DOT1L) was necessary and sufficient for increased H3K79me2/3 occupancy at the IL1A gene locus, but not other SASP genes, and was downstream of STING. Modulating DOT1L expression did not affect the cell cycle arrest. Together, our studies establish DOT1L as an epigenetic regulator of the SASP, whose expression is uncoupled from the senescence-associated cell cycle arrest, providing a potential strategy to inhibit the negative side effects of senescence while maintaining the beneficial inhibition of proliferation.

Aging and Mesenchymal Stem Cells: Therapeutic Opportunities and Challenges in the Older Group

With aging, a portion of cells, including mesenchymal stem cells (MSCs), become senescent, and these senescent cells accumulate and promote various age-related diseases. Therefore, the older age group has become a major population for MSC therapy, which is aimed at improving tissue regeneration and function of the aged body. However, the application of MSC therapy is often unsatisfying in the aged group. One reasonable conjecture for this correlation is that aging microenvironment reduces the number and function of MSCs. Cellular senescence also plays an important role in MSC function impairment. Thus, it is necessary to explore the relationship between senescence and MSCs for improving the application of MSCs in the elderly. Here, we present the influence of aging on MSCs and the characteristics and functional changes of senescent MSCs. Furthermore, current therapeutic strategies for improving MSC therapy in the elderly group are also discussed.

Role of Extracellular Vesicles in Placental Inflammation and Local Immune Balance

Background

Pregnancy maintenance depends on the formation of normal placentas accompanied by trophoblast invasion and vascular remodeling. Various types of cells, such as trophoblasts, endothelial cells, immune cells, mesenchymal stem cells (MSCs), and adipocytes, mediate cell-to-cell interactions through soluble factors to maintain normal placental development. Extracellular vesicles (EVs) are diverse nanosized to microsized membrane-bound particles released from various cells. EVs contain tens to thousands of different RNA, proteins, small molecules, DNA fragments, and bioactive lipids. EV-derived microRNAs (miRNAs) and proteins regulate inflammation and trophoblast invasion in the placental microenvironment. Maternal-fetal communication through EV can regulate the key signaling pathways involved in pregnancy maintenance, from implantation to immune regulation. Therefore, EVs and the encapsulating factors play important roles in pregnancy, some of which might be potential biomarkers.

Conclusion

In this review, we have summarized published studies about the EVs in the placentation and pregnancy-related diseases. By summarizing the role of EVs and their delivering active molecules in pregnancy-related diseases, it provides novel insight into the diagnosis and treatment of diseases.

National Institute on Aging Workshop: Repurposing Drugs or Dietary Supplements for Their Senolytic or Senomorphic Effects: Considerations for Clinical Trials

BACKGROUND

Cell senescence is implicated in numerous age-related conditions. Drugs and nutritional supplements developed for a variety of purposes kill senescent cells (senolytics) or suppress their secretions (senomorphics). There is interest in repurposing such drugs to treat or prevent age-related diseases. To date, only small-scale preliminary trials have been conducted.

METHOD

At a workshop convened by the National Institute on Aging in August 2019, academic, industry, and government scientists reviewed issues for phase II trials of potentially repurposable drugs, or dietary supplements, to assess benefits and risks of their senolytic (killing senescent cells) or senomorphic (altering senescent cells' phenotypes) effects in treating or preventing age-related conditions.

RESULTS

Participants reviewed mechanisms and effects of cellular senescence, senolytics, and senomorphics of several classes and their potential role in treating or preventing disease, modulators of the senescence-associated secretory phenotype, needs for senescence markers, data and specimen resources, infrastructure for planning trials, and potential effects on outcomes in older patients with multimorbidity and polypharmacy.

CONCLUSIONS

Participants noted the importance of considering potential effects of candidate drugs on multiple aging outcomes. It is important to assess drugs' specificity for killing senescent cells and the balance between senolytic and cytotoxic effects. Markers of specific senescent cell types are needed to assess intervention responses. There are potential interactions with coexisting diseases and their treatments in older persons. Standardized measures could enhance comparisons and pooling of data. Additional characterization of human cell senescent phenotypes is needed for developing better and more specific senolytics and senomorphics.

Comparable in vitro Function of Human Liver-Derived and Adipose Tissue-Derived Mesenchymal Stromal Cells: Implications for Cell-Based Therapy

Mesenchymal stem/stromal cells (MSCs) have been investigated extensively for their immunotherapeutic and regenerative properties, which may differ by cell source. In MSCs harvested from donors matched for sex, age, and body mass index, we compared the proliferative and migration functions of liver-derived MSCs (L-MSCs) and adipose tissue-derived MSCs (A-MSCs) (n = 6 donors each). Cellular senescence was evaluated by senescence-associated beta-galactosidase enzyme activity and expression of senescence-associated secretory phenotype (SASP) factors using real-time quantitative polymerase chain and by western blot assay. The pro-angiogenic and reparative potency of MSCs was compared by co-culturing MSCs with injured human umbilical vein endothelial cells (HUVEC). The proliferation and migration properties were similar in L-MSCs and A-MSCs. Although cell cycle arrest and SASP genes were similarly expressed in both MSCs, tumor necrosis factor alpha gene and protein expression were significantly downregulated in L-MSCs. In co-cultured injured HUVEC, A-MSCs restored significantly more tubes and tube connections than L-MSCs. Therefore, despite many functional similarities between L-MSCs and A-MSCs, L-MSCs have enhanced immunomodulatory properties, while A-MSCs appear to have better pro-angiogenic and vascular reparative potency. Availability of a broad range of cellular options might enable selecting cell-based therapy appropriate for the specific underlying disease.

New Horizons: Novel Approaches to Enhance Healthspan Through Targeting Cellular Senescence and Related Aging Mechanisms

The elderly population is increasing faster than other segments of the population throughout the world. Age is the leading predictor for most chronic diseases and disorders, multimorbidity, geriatric syndromes, and impaired ability to recover from accidents or illnesses. Enhancing the duration of health and independence, termed healthspan, would be more desirable than extending lifespan merely by prolonging the period of morbidity toward the end of life. The geroscience hypothesis posits that healthspan can be extended by targeting fundamental aging mechanisms, rather than attempting to address each age-related disease one at a time, only so the afflicted individual survives disabled and dies shortly afterward of another age-related disease. These fundamental aging mechanisms include, among others, chronic inflammation, fibrosis, stem cell/ progenitor dysfunction, DNA damage, epigenetic changes, metabolic shifts, destructive metabolite generation, mitochondrial dysfunction, misfolded or aggregated protein accumulation, and cellular senescence. These processes appear to be tightly interlinked, as targeting any one appears to affect many of the rest, underlying our Unitary Theory of Fundamental Aging Mechanisms. Interventions targeting many fundamental aging processes are being developed, including dietary manipulations, metformin, mTOR (mechanistic target of rapamycin) inhibitors, and senolytics, which are in early human trials. These interventions could lead to greater healthspan benefits than treating age-related diseases one at a time. To illustrate these points, we focus on cellular senescence and therapies in development to target senescent cells. Combining interventions targeting aging mechanisms with disease-specific drugs could result in more than additive benefits for currently difficult-to-treat or intractable diseases. More research attention needs to be devoted to targeting fundamental aging processes.

Partial recovery of senescence in circulating follicular helper T cells after Dasatinib treatment

Cellular senescence is an irreversible arrest of cell proliferation triggered by different stimuli, including DNA damage, telomere shortening and oncogenic stress. Senescent cells, by releasing the senescence-associated-secretory-phenotype (SASP), contribute to various diseases pathogenesis. Human atherosclerotic plaque contains cells with multiple markers of senescence that associate with disease severity. We characterized the frequency of senescent cTfh cells and genes expressions before and after treatment with Dasatinib in patients with different degrees of stenosis. Twelve high (≥50%), and twelve low (<50%) stenosis patients and six healthy controls were enrolled. The percentage of senescent CD3⁺CD4⁺CXCR5⁺CD153⁺CD57⁺ cells was significantly decreased in Dasatinib treated cells from individuals with low and high stenosis (P = 0.0007 and P = 0.0002, respectively). However, the frequency of total lymphocytes, CD3⁺ and CD4⁺ T cells were not significantly different between the groups before and after treatment. The expression levels of P53 (P = 0.0003 and P = 0.0001), P16 (P = 0.0005 and P = 0.0002), p21 (P = 0.0002 and P < 0.0001), SENEX (P = 0.0005 and P < 0.0001) and BCL-2 (P = 0.0005 and P = 0.0002) were decreased in PBMCs of low and high stenosis groups after treatment with Dasatinib, respectively. The percentage of senescent cTfh cells positively correlated with cholesterol (P = 0.034; r = 0.671), C-reactive protein (CRP) (P = 0.029; r = 0.707), Erythrocyte sedimentation rate (ESR) levels (P = 0.030; r = 0.598) and neutrophil counts (P = 0.021; r = 0.799) in patients with high stenosis. The decreased frequency of senescent cTfh cells and the expression levels of senescence genes after Dasatinib treatment in patients with atherosclerosis suggest a role for Dasatinib in partial clearance or rejuvenation of senescent cTfh cells, which may decrease inflammatory mediators and attenuate disease progression.

The Impact of Polyphenols-Based Diet on the Inflammatory Profile in COVID-19 Elderly and Obese Patients

The World Health Organization declared the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated disease (coronavirus disease 2019 - COVID-19) as a pandemic in March 2020. COVID-19 is characterized by cytokine storm, acute respiratory distress syndrome (ARDS), and systemic inflammation-related pathology and already kills more than 1.5 million of people worldwide. Since aged and obese COVID-19 patients exhibit an enhanced inflammatory status, they represent a high-risk cluster for rapidly progressive clinical deterioration. These individuals present comorbid disorders and immunosenescence that may promote viral-induced cytokine storm and expression of molecules acting as virus receptor as angiotensin I converting enzyme 2 (ACE2) and CD26 (dipeptidyl-peptidase 4), resulting in respiratory failure and increased morbidity and mortality. A better knowledge of SARS-CoV-2 infection in inflammatory-associated high-risk population is essential in order to develop the therapies needed to combat or prevent severe COVID-19. Here, we review the pathogenesis and clinical implications of inflammatory disorders and disease markers associated to senescence in COVID-19 patients and the emerging evidence to argue that a high intake of polyphenols may have a protective effect on SARS-CoV-2 illness severity.

Incidence and Long-Term Outcomes of Hypertensive Disorders of Pregnancy

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are associated with increased risks for cardiovascular disease later in life. The HDP incidence is commonly assessed using diagnostic codes, which are not reliable; and typically are expressed per-pregnancy, which may underestimate the number of women with an HDP history after their reproductive years.

OBJECTIVES

This study sought to determine the incidence of HDP expressed as both per-pregnancy and per-woman, and to establish their associations with future chronic conditions and multimorbidity, a measure of accelerated aging, in a population-based cohort study.

METHODS

Using the Rochester Epidemiology Project medical record-linkage system, the authors identified residents of Olmsted County, Minnesota, who delivered between 1976 and 1982. The authors classified pregnancies into normotensive, gestational hypertension, pre-eclampsia, eclampsia, pre-eclampsia superimposed on chronic hypertension, and chronic hypertension using a validated electronic algorithm, and calculated the incidence of HDP both per-pregnancy and per-woman. The risk of chronic conditions between women with versus those without a history of HDP (age and parity 1:2 matched) was quantified using the hazard ratio and corresponding 95% confidence interval estimated from a Cox model.

RESULTS

Among 9,862 pregnancies, we identified 719 (7.3%) with HDP and 324 (3.3%) with pre-eclampsia. The incidence of HDP and pre-eclampsia doubled when assessed on a per-woman basis: 15.3% (281 of 1,839) and 7.5% (138 of 1,839), respectively. Women with a history of HDP were at increased risk for subsequent diagnoses of stroke (hazard ratio [HR]: 2.27; 95% confidence interval [CI]: 1.37 to 3.76), coronary artery disease (HR: 1.89; 95% CI: 1.26 to 2.82), cardiac arrhythmias (HR: 1.62; 95% CI: 1.28 to 2.05), chronic kidney disease (HR: 2.41; 95% CI: 1.54 to 3.78), and multimorbidity (HR: 1.25; 95% CI: 1.15 to 1.35).

CONCLUSIONS

The HDP population-based incidence expressed per-pregnancy underestimates the number of women affected by this condition during their reproductive years. A history of HDP confers significant increase in risks for future chronic conditions and multimorbidity.

Analysis of Hub Genes Involved in Distinction Between Aged and Fetal Bone Marrow Mesenchymal Stem Cells by Robust Rank Aggregation and Multiple Functional Annotation Methods

Stem cells from fetal tissue protect against aging and possess greater proliferative capacity than their adult counterparts. These cells can more readily expand in vitro and senesce later in culture. However, the underlying molecular mechanisms for these differences are still not fully understood. In this study, we used a robust rank aggregation (RRA) method to discover robust differentially expressed genes (DEGs) between fetal bone marrow mesenchymal stem cells (fMSCs) and aged adult bone marrow mesenchymal stem cells (aMSCs). Multiple methods, including gene set enrichment analysis (GSEA), Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed for functional annotation of the robust DEGs, and the results were visualized using the R software. The hub genes and other genes with which they interacted directly were detected by protein–protein interaction (PPI) network analysis. Correlation of gene expression was measured by Pearson correlation coefficient. A total of 388 up-regulated and 289 down-regulated DEGs were identified between aMSCs and fMSCs. We found that the down-regulated genes were mainly involved in the cell cycle, telomerase activity, and stem cell proliferation. The up-regulated DEGs were associated with cell adhesion molecules, extracellular matrix (ECM)–receptor interactions, and the immune response. We screened out four hub genes, MYC, KIF20A, HLA-DRA, and HLA-DPA1, through PPI-network analysis. The MYC gene was negatively correlated with TXNIP, an age-related gene, and KIF20A was extensively involved in the cell cycle. The results suggested that MSCs derived from the bone marrow of an elderly donor present a pro-inflammatory phenotype compared with that of fMSCs, and the HLA-DRA and HLA-DPA1 genes are related to the immune response. These findings provide new insights into the differences between aMSCs and fMSCs and may suggest novel strategies for ex vivo expansion and application of adult MSCs.

Targeting Senescent Cells for a Healthier Aging: Challenges and Opportunities

Aging is a physiological decline in both structural homeostasis and functional integrity, progressively affecting organismal health. A major hallmark of aging is the accumulation of senescent cells, which have entered a state of irreversible cell cycle arrest after experiencing inherent or environmental stresses. Although cellular senescence is essential in several physiological events, it plays a detrimental role in a large array of age-related pathologies. Recent biomedical advances in specifically targeting senescent cells to improve healthy aging, or alternatively, postpone natural aging and age-related diseases, a strategy termed senotherapy, have attracted substantial interest in both scientific and medical communities. Challenges for aging research are highlighted and potential avenues that can be leveraged for therapeutic interventions to control aging and age-related disorders in the current era of precision medicine.

Hypertensive Disorders of Pregnancy

Hypertensive disorders of pregnancy are increasing in incidence and are major causes of maternal morbidity and mortality both in the United States and worldwide. An understanding of these diseases is essential for the practicing nephrologist, as preexisting kidney disease is an important risk factor. In addition, the development of hypertensive disorders of pregnancy has important implications for long-term risk of kidney disease and cardiovascular disease. The definition and diagnostic criteria has changed in recent years as our understanding of the disease entity has progressed. Currently, proteinuria is no longer a necessary diagnostic feature of preeclampsia. Preeclampsia and gestational hypertension may develop through multiple different mechanisms. Current research suggests contributions of both placental factors and maternal factors contribute to the disease and represent different phenotypic presentations of preeclampsia.

Senolytic drugs: from discovery to translation

Senolytics are a class of drugs that selectively clear senescent cells (SC). The first senolytic drugs Dasatinib, Quercetin, Fisetin and Navitoclax were discovered using a hypothesis-driven approach. SC accumulate with ageing and at causal sites of multiple chronic disorders, including diseases accounting for the bulk of morbidity, mortality and health expenditures. The most deleterious SC are resistant to apoptosis and have up-regulation of anti-apoptotic pathways which defend SC against their own inflammatory senescence-associated secretory phenotype (SASP), allowing them to survive, despite killing neighbouring cells. Senolytics transiently disable these SCAPs, causing apoptosis of those SC with a tissue-destructive SASP. Because SC take weeks to reaccumulate, senolytics can be administered intermittently - a 'hit-and-run' approach. In preclinical models, senolytics delay, prevent or alleviate frailty, cancers and cardiovascular, neuropsychiatric, liver, kidney, musculoskeletal, lung, eye, haematological, metabolic and skin disorders as well as complications of organ transplantation, radiation and cancer treatment. As anticipated for agents targeting the fundamental ageing mechanisms that are 'root cause' contributors to multiple disorders, potential uses of senolytics are protean, potentially alleviating over 40 conditions in preclinical studies, opening a new route for treating age-related dysfunction and diseases. Early pilot trials of senolytics suggest they decrease senescent cells, reduce inflammation and alleviate frailty in humans. Clinical trials for diabetes, idiopathic pulmonary fibrosis, Alzheimer's disease, COVID-19, osteoarthritis, osteoporosis, eye diseases and bone marrow transplant and childhood cancer survivors are underway or beginning. Until such studies are done, it is too early for senolytics to be used outside of clinical trials.

Mechanisms of Key Innate Immune Cells in Early- and Late-Onset Preeclampsia

Preeclampsia is a complex cardiovascular disorder of pregnancy with underlying multifactorial pathogeneses; however, its etiology is not fully understood. It is characterized by the new onset of maternal hypertension after 20 weeks of gestation, accompanied by proteinuria, maternal organ damage, and/or uteroplacental dysfunction. Preeclampsia can be subdivided into early- and late-onset phenotypes (EOPE and LOPE), diagnosed before 34 weeks or from 34 weeks of gestation, respectively. Impaired placental development in early pregnancy and subsequent growth restriction is often associated with EOPE, while LOPE is associated with maternal endothelial dysfunction. The innate immune system plays an essential role in normal progression of physiological pregnancy and fetal development. However, inappropriate or excessive activation of this system can lead to placental dysfunction or poor maternal vascular adaptation and contribute to the development of preeclampsia. This review aims to comprehensively outline the mechanisms of key innate immune cells including macrophages, neutrophils, natural killer (NK) cells, and innate B1 cells, in normal physiological pregnancy, EOPE and LOPE. The roles of the complement system, syncytiotrophoblast extracellular vesicles and mesenchymal stem cells (MSCs) are also discussed in the context of innate immune system regulation and preeclampsia. The outlined molecular mechanisms, which represent potential therapeutic targets, and associated emerging treatments, are evaluated as treatments for preeclampsia. Therefore, by addressing the current understanding of innate immunity in the pathogenesis of EOPE and LOPE, this review will contribute to the body of research that could lead to the development of better diagnosis, prevention, and treatment strategies. Importantly, it will delineate the differences in the mechanisms of the innate immune system in two different types of preeclampsia, which is necessary for a more personalized approach to the monitoring and treatment of affected women.

Activation of SIRT1 promotes cartilage differentiation and reduces apoptosis of nucleus pulposus mesenchymal stem cells via the MCP1/CCR2 axis in subjects with intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a condition involving disruption of the bone tissue distribution. Nucleus pulposus mesenchymal stem cells (NPMSCs) and Sirtuin 1 (SIRT1) play important roles in bone diseases, therefore the aim of the present study was to evaluate the roles of SIRT1 and NPMSCs in IDD. First, NPMSCs were harvested from patients with IDD. Then, the NPMSCs were treated with a SIRT activator, and monocyte chemoattractant protein 1 (MCP1) and chemokine receptor 2 (CCR2) inhibitors. Indices related to NPMSC growth, proliferation, differentiation and apoptosis were measured. Subsequently, IDD rat models were established and were transfected with NPMSCs overexpressing SIRT1. NPMSC apoptosis and cartilage differentiation were detected in the rat IDD model. SIRT1 expression was found to be decreased, and the expression of MCP1 and CCR2 increased in NPMSCs of patients with IDD. The upregulation of SIRT1 and the downregulation of the MCP1/CCR2 axis promoted cartilage differentiation and reduced the number of apoptotic NPMSCs. Furthermore, MCP1 reversed the progression of the cartilage differentiation of NPMSCs and the inhibition of NPMSC apoptosis induced by SIRT1 overexpression. Moreover, the transplantation of rat NPMSCs overexpressing SIRT1 relieved IDD in rats. Therefore, SIRT1 overexpression improved cartilage differentiation and reduced the apoptosis of NPMSCs by inactivating the MCP1/CCR2 axis, thus attenuating IDD in rats.

The role of cellular senescence in ageing and endocrine disease

With the ageing of the global population, interest is growing in the 'geroscience hypothesis', which posits that manipulation of fundamental ageing mechanisms will delay (in parallel) the appearance or severity of multiple chronic, non-communicable diseases, as these diseases share the same underlying risk factor - namely, ageing. In this context, cellular senescence has received considerable attention as a potential target in preventing or treating multiple age-related diseases and increasing healthspan. Here we review mechanisms of cellular senescence and approaches to target this pathway therapeutically using 'senolytic' drugs that kill senescent cells or inhibitors of the senescence-associated secretory phenotype (SASP). Furthermore, we highlight the evidence that cellular senescence has a causative role in multiple diseases associated with ageing. Finally, we focus on the role of cellular senescence in a number of endocrine diseases, including osteoporosis, metabolic syndrome and type 2 diabetes mellitus, as well as other endocrine conditions. Although much remains to be done, considerable preclinical evidence is now leading to the initiation of proof-of-concept clinical trials using senolytics for several endocrine and non-endocrine diseases.

Reducing Senescent Cell Burden in Aging and Disease

Cellular senescence is a primary aging process and tumor suppressive mechanism characterized by irreversible growth arrest, apoptosis resistance, production of a senescence-associated secretory phenotype (SASP), mitochondrial dysfunction, and alterations in DNA and chromatin. In preclinical aging models, accumulation of senescent cells is associated with multiple chronic diseases and disorders, geriatric syndromes, multimorbidity, and accelerated aging phenotypes. In animals, genetic and pharmacologic reduction of senescent cell burden results in the prevention, delay, and/or alleviation of a variety of aging-related diseases and sequelae. Early clinical trials have thus far focused on safety and target engagement of senolytic agents that clear senescent cells. We hypothesize that these pharmacologic interventions may have transformative effects on geriatric medicine.

Emerging Therapeutic Potential of Mesenchymal Stem/Stromal Cells in Preeclampsia

PURPOSE OF REVIEW

Preeclampsia is a dangerous pregnancy condition affecting both the mother and offspring. It is a multifactorial disease with poorly understood pathogenesis, lacking effective treatments. Maternal immune response, inflammation and oxidative stress leading to endothelial dysfunction are the most prominent pathogenic processes implicated in preeclampsia development. Here, we give a detailed overview of the therapeutic applications and mechanisms of mesenchymal stem/stromal cells (MSCs) as a potential new treatment for preeclampsia.

RECENT FINDINGS

MSCs have gained growing attention due to low immunogenicity, easy cultivation and expansion in vitro. Accumulating evidence now suggests that MSCs act primarily through their secretomes facilitating paracrine signalling that leads to potent immunomodulatory, pro-angiogenic and regenerative therapeutic effects. MSCs have been studied in different animal models of preeclampsia demonstrating promising result, which support further investigations into the therapeutic effects and mechanisms of MSC-based therapies in preeclampsia, steering these therapies into clinical trials.