Mesenchymal Stem Cell Therapy for Aging Frailty

Towards Healthy Longevity: Comprehensive Insights from Molecular Targets and Biomarkers to Biological Clocks

Aging is a complex and time-dependent decline in physiological function that affects most organisms, leading to increased risk of age-related diseases. Investigating the molecular underpinnings of aging is crucial to identify geroprotectors, precisely quantify biological age, and propose healthy longevity approaches. This review explores pathways that are currently being investigated as intervention targets and aging biomarkers spanning molecular, cellular, and systemic dimensions. Interventions that target these hallmarks may ameliorate the aging process, with some progressing to clinical trials. Biomarkers of these hallmarks are used to estimate biological aging and risk of aging-associated disease. Utilizing aging biomarkers, biological aging clocks can be constructed that predict a state of abnormal aging, age-related diseases, and increased mortality. Biological age estimation can therefore provide the basis for a fine-grained risk stratification by predicting all-cause mortality well ahead of the onset of specific diseases, thus offering a window for intervention. Yet, despite technological advancements, challenges persist due to individual variability and the dynamic nature of these biomarkers. Addressing this requires longitudinal studies for robust biomarker identification. Overall, utilizing the hallmarks of aging to discover new drug targets and develop new biomarkers opens new frontiers in medicine. Prospects involve multi-omics integration, machine learning, and personalized approaches for targeted interventions, promising a healthier aging population.

Renal protective effects of Alpinate Oxyphyllae Fructus and mesenchymal stem cells co-treatment against D- galactose induced renal deterioration

Age-related structural and functional changes in the kidney can eventually lead to development of chronic kidney disease, which is one of the leading causes of mortality among elderly people. For effective management of age-related kidney complications, it is important to identify new therapeutic interventions with minimal side-effects. The present study was designed to evaluate the synergistic effect of a traditional Chinese herb, Alpinate Oxyphyllae Fructus (AOF), and adipose-derived mesenchymal stem cells (ADMSCs) in ameliorating D-galactose (D-gal)-induced renal aging phenotypes in WKY rats. The study findings showed that D-gal-induced alteration in the kidney morphology was partly recovered by the AOF and ADMSC co-treatment. Moreover, the AOF and ADMSC co-treatment reduced the expression of proinflammatory mediators (NFkB, IL-6, and Cox2) and increased the expression of redox regulators (Nrf2 and HO-1) in the kidney, which were otherwise augmented by the D-gal treatment. Regarding kidney cell death, the AOF and ADMSC co-treatment was found to abolish the proapoptotic effects of D-gal by downregulating Bax and Bad expressions and inhibiting caspase 3 activation. Taken together, the study findings indicate that the AOF and ADMSC co-treatment protect the kidney from D-gal-induced aging by reducing cellular inflammation and oxidative stress and inhibiting renal cell death. This study can open up a new path toward developing novel therapeutic interventions using both AOF and ADMSC to effectively manage age-related renal deterioration.

Emerging Strategies in Mesenchymal Stem Cell-Based Cardiovascular Therapeutics

Cardiovascular diseases continue to challenge global health, demanding innovative therapeutic solutions. This review delves into the transformative role of mesenchymal stem cells (MSCs) in advancing cardiovascular therapeutics. Beginning with a historical perspective, we trace the development of stem cell research related to cardiovascular diseases, highlighting foundational therapeutic approaches and the evolution of cell-based treatments. Recognizing the inherent challenges of MSC-based cardiovascular therapeutics, which range from understanding the pro-reparative activity of MSCs to tailoring patient-specific treatments, we emphasize the need to refine the pro-regenerative capacity of these cells. Crucially, our focus then shifts to the strategies of the fourth generation of cell-based therapies: leveraging the secretomic prowess of MSCs, particularly the role of extracellular vesicles; integrating biocompatible scaffolds and artificial sheets to amplify MSCs' potential; adopting three-dimensional ex vivo propagation tailored to specific tissue niches; harnessing the promise of genetic modifications for targeted tissue repair; and institutionalizing good manufacturing practice protocols to ensure therapeutic safety and efficacy. We conclude with reflections on these advancements, envisaging a future landscape redefined by MSCs in cardiovascular regeneration. This review offers both a consolidation of our current understanding and a view toward imminent therapeutic horizons.

Addressing the Missing Links in Cardiovascular Aging

The aim of this manuscript is to provide a review of available options to enhance cardiovascular health and prevent cardiovascular disease (CVD) in the aging population using a systems-biology approach. These include the role of the gut microbiome, the early identification and removal of environmental toxins, and finally age related sex hormones and supplement replacement which all influence aging. Implementing such a comprehensive approach has the potential to facilitate earlier risk assessment, disease prevention, and even improve mortality. Further study in these areas will continue to advance our understanding and refine therapeutic interventions for a healthier cardiovascular aging process.

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Transcriptomic and intervention evidence reveals domestic dogs as a promising model for anti-inflammatory investigation

Domestic dogs have great potential to expand our understanding of the determinants of aging. To understand the aging pattern of domestic dogs and evaluate whether they can be used as an aging model, we performed RNA sequencing on white blood cells from domestic dogs aged 1-9 years and treated aged dogs with classical antiaging approaches. We obtained 30 RNA sequencing libraries and identified 61 age-associated genes with dynamic changes, the majority of which were related to metabolism and immune function, which may be predominant biomarkers for aging in dogs. We next treated aged dogs with canine mesenchymal stem cells (cMSCs), nicotinamide mononucleotide, and rapamycin to determine whether and how they responded to the antiaging interventions. The results showed that these treatments can significantly reduce the level of inflammatory factors (IL-6 and TNF-α). MSCs effectively improved the heart functions of aged dogs. Three key potential age-related genes (PYCR1, CCRL2, and TOX) were reversed by MSC treatment, two of which (CCRL2 and TOX) are implicated in immunity. Overall, we profiled the transcriptomic pattern of domestic dogs and revealed that they may be a good model of aging, especially in anti-inflammatory investigations.

Safety and efficacy of umbilical cord tissue-derived mesenchymal stem cells in the treatment of patients with aging frailty: a phase I/II randomized, double-blind, placebo-controlled study

BACKGROUND

Mesenchymal stem cells (MSCs) hold a great promise for cell-based therapy in the field of regenerative medicine. In this study, we aimed to evaluate the safety and efficacy of intravenous infusion of human umbilical cord-derived MSCs (HUC-MSCs) in patients with aging frailty.

METHODS

In this randomized, double-blind, placebo-controlled trial, participants diagnosed with aging frailty were randomly assigned to receive intravenous administrations of HUC-MSCs or placebo. All of serious adverse events and AEs were monitored to evaluate the safety of treatment during the 6-month follow-up. The primary efficacy endpoint was alteration of physical component scores (PCS) of SF-36 qualities of life at 6 months. The secondary outcomes including physical performance tests and pro-inflammatory cytokines, were also observed and compared at each follow-up visits. All evaluations were performed at 1 week, 1, 2, 3 and 6 months following the first intravenous infusion of HUC-MSCs.

RESULTS

In the MSCs group, significant improvements in PCS of SF-36 were observed from first post-treatment visit and sustained throughout the follow-up period, with greater changes compared to the placebo group (p = 0.042). EQ-VAS scores of MSCs group improved significantly at 2 month (p = 0.023) and continued until the end of the 6-month visit (p = 0.002) in comparison to the placebo group. The timed up and go (TUG) physical performance test revealed significant group difference and showed continual enhancements over 6 months (p < 0.05). MSC transplantation improved the function of 4-m walking test (4MWT) compared with the placebo group with a decrease of 2.05 s at 6 months of follow-up (p = 0.21). The measurement of grip strength revealed group difference with MSCs group demonstrating better performance, particularly at 6 months (p = 0.002). Inflammatory cytokines (TNF-α, IL-17) exhibited declines in MSCs group at 6 months compared to the placebo group (p = 0.034 and 0.033, respectively). There was no difference of incidence of AEs between the two groups.

CONCLUSION

Intravenous transplantation of HUC-MSCs is a safe and effective therapeutic approach on aging frailty. The positive outcomes observed in improving quality of life, physical performance, and reducing chronic inflammation, suggest that HUC-MSC therapy may be a promising potential treatment option for aging frailty.

TRIAL REGISTRATION

Clinicaltrial.gov; NCT04314011; https://clinicaltrials.gov/ct2/show/NCT04314011 .

Emerging role of mesenchymal stem cells-derived extracellular vesicles in vascular dementia

Vascular dementia (VD) is a prevalent cognitive disorder among the elderly. Its pathological mechanism encompasses neuronal damage, synaptic dysfunction, vascular abnormalities, neuroinflammation, and oxidative stress, among others. In recent years, extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have garnered significant attention as an emerging therapeutic strategy. Current research indicates that MSC-derived extracellular vesicles (MSC-EVs) play a pivotal role in both the diagnosis and treatment of VD. Thus, this article delves into the recent advancements of MSC-EVs in VD, discussing the mechanisms by which EVs influence the pathophysiological processes of VD. These mechanisms form the theoretical foundation for their neuroprotective effect in VD treatment. Additionally, the article highlights the potential applications of EVs in VD diagnosis. In conclusion, MSC-EVs present a promising innovative treatment strategy for VD. With rigorous research and ongoing innovation, this concept can transition into practical clinical treatment, providing more effective options for VD patients.

Therapeutic Approaches to Increase the Survival Rate of Cancer Patients in the Younger and Older Population

Various developments have been observed in the treatment of cancer patients, such as higher survival rates and better treatment outcomes. However, expecting similar outcomes in older patients remains a challenge. The main reason for this conclusion is the exclusion of older people from clinical trials for cancer drugs, as well as other factors, such as comorbidity, side effects, age-related frailties and their willingness to undergo multiple treatments. However, the discovery of new techniques and drug combinations has led to a significant improvement in the survival of the elderly population after the onset of the disease. On the other hand, cancer treatments have not become more complex for the younger population when compared to the older population, as the younger population tends to respond well to treatment trials and their physiological conditions are stable in response to treatments. In summary, this review correlates recent cancer treatment strategies and the corresponding responses and survival outcomes of older and younger patients.

M2-Macrophage-Induced Chronic Inflammation Promotes Reversible Mesenchymal Stromal Cell Senescence and Reduces Their Anti-Fibrotic Properties

Fibrosis and the associated decline in organ functionality lead to an almost 50% mortality rate in developed countries. Multipotent mesenchymal stromal cells (MSC) were shown to suppress the development and progression of fibrosis through secreted factors including specific non-coding RNAs transferred within extracellular vesicles (EV). However, age-associated chronic inflammation can provoke MSC senescence and change secretome composition, thereby affecting their antifibrotic properties. Alternatively activated macrophages (M2-type) are key players in chronic inflammation that may interact with MSC through paracrine mechanisms and decrease their antifibrotic functions. To confirm this hypothesis, we evaluated the M2-macrophage conditioned medium (CM-M2) effect on human adipose-tissue-derived MSC senescence in vitro. We found that CM-M2, as well as a pro-senescence agent, hydrogen peroxide (H2O2), increased p21+-MSC number and secretion of IL-6 and MCP-1, which are considered main senescence-associated secretory phenotype (SASP) components. Thus, both exposures led to the senescent phenotype acquisition of MSC. EV from both CM-M2 and H2O2-exposed MSC, which showed a decreased effect on the suppression of TGFβ-induced fibroblast-to-myofibroblast differentiation compared to EV from control MSC according to αSMA level and the αSMA+-stress fiber reduction. After two weeks of subsequent cultivation under standard conditions, MSC demonstrated a decrease in senescence hallmarks and fibroblast differentiation suppression via EV. These results suggest that M2-macrophage-induced chronic inflammation can reversibly induce MSC senescence, which reduces the MSC's ability to inhibit fibroblast-to-myofibroblast differentiation.

Assessing the Predictive Power of Frailty and Life-Space Mobility on Patient-Reported Outcomes of Disability in Older Adults with Low Back Pain

Background: Frailty and decreased life-space mobility are known as risk factors to develop physical limitations leading to disability in older adults with low back pain (LBP). This cross sectional study aimed to investigate the prevalence and predictive power of frailty and life-space mobility on patient-reported outcomes of disability in older adults with LBP. Methods: The sample comprised 165 older adults with LBP who visited two tertiary care hospitals between December 2021 and February 2022. The participants responded to structured standard questionnaires. Data were analyzed using descriptive statistics and robust logistic regression. Results: More than two-thirds of participants were classified as non-frail (26.67%) or pre-frail (66.67%). Mobility restrictions and minimal to severe disability were identified. Controlling other variables, frailty (OR = 1.74, 95% CI: 1.14–2.64) and restricted life-space mobility (OR = 0.42, 95% CI: 0.26–0.67) were significantly associated with disability. Integrating frailty with life-space mobility evaluations demonstrated the highest predictive power for disability-related LBP (AUC = 0.89, 95% CI: 0.84–0.93). Conclusion: Frailty and restricted life-space mobility significantly predicted disability in older adults with LBP. Healthcare professionals should recognize the critical importance of integrating patient-reported outcomes with screening for frailty and life-space mobility limitation to optimize care or tract symptom progression.

Young bone marrow transplantation prevents aging-related muscle atrophy in a senescence-accelerated mouse prone 10 model

BACKGROUND

Young bone marrow transplantation (YBMT) has been shown to stimulate vascular regeneration in pathological conditions, including ageing. Here, we investigated the benefits and mechanisms of the preventive effects of YBMT on loss of muscle mass and function in a senescence-associated mouse prone 10 (SAMP10) model, with a special focus on the role of growth differentiation factor 11 (GDF-11).

METHODS

Nine-week-old male SAMP10 mice were randomly assigned to a non-YBMT group (n = 6) and a YBMT group (n = 7) that received the bone marrow of 8-week-old C57BL/6 mice.

RESULTS

Compared to the non-YBMT mice, the YBMT mice showed the following significant increases (all P < 0.05 in 6-7 mice): endurance capacity (>61.3%); grip strength (>37.9%), percentage of slow myosin heavy chain fibres (>14.9-15.9%). The YBMT also increased the amounts of proteins or mRNAs for insulin receptor substrate 1, p-Akt, p-extracellular signal-regulated protein kinase1/2, p-mammalian target of rapamycin, Bcl-2, peroxisom proliferator-activated receptor-γ coactivator (PGC-1α), plus cytochrome c oxidase IV and the numbers of proliferating cells (n = 5-7, P < 0.05) and CD34+/integrin-α7+ muscle stem cells (n = 5-6, P < 0.05). The YMBT significantly decreased the levels of gp91phox, caspase-9 proteins and apoptotic cells (n = 5-7, P < 0.05) in both muscles; these beneficial changes were diminished by the blocking of GDF-11 (n = 5-6, P < 0.05). An administration of mouse recombinant GDF-11 improved the YBMT-mediated muscle benefits (n = 5-6, P < 0.05). Cell therapy with young bone marrow from green fluorescent protein (GFP) transgenic mice exhibited GFP+ myofibres in aged muscle tissues.

CONCLUSIONS

These findings suggest that YBMT can prevent muscle wasting and dysfunction by mitigating apoptosis and proliferation via a modulation of GDF-11 signalling and mitochondrial dysfunction in SAMP10 mice.

Aging and Mesenchymal Stem Cells: Basic Concepts, Challenges and Strategies

Aging and frailty are complex processes implicating multifactorial mechanisms, such as replicative senescence, oxidative stress, mitochondrial dysfunction, or autophagy disorder. All of these mechanisms drive dramatic changes in the tissue environment, such as senescence-associated secretory phenotype factors and inflamm-aging. Thus, there is a demand for new therapeutic strategies against the devastating effects of the aging and associated diseases. Mesenchymal stem cells (MSC) participate in a "galaxy" of tissue signals (proliferative, anti-inflammatory, and antioxidative stress, and proangiogenic, antitumor, antifibrotic, and antimicrobial effects) contributing to tissue homeostasis. However, MSC are also not immune to aging. Three strategies based on MSC have been proposed: remove, rejuvenate, or replace the senescent MSC. These strategies include the use of senolytic drugs, antioxidant agents and genetic engineering, or transplantation of younger MSC. Nevertheless, these strategies may have the drawback of the adverse effects of prolonged use of the different drugs used or, where appropriate, those of cell therapy. In this review, we propose the new strategy of "Exogenous Restitution of Intercellular Signalling of Stem Cells" (ERISSC). This concept is based on the potential use of secretome from MSC, which are composed of molecules such as growth factors, cytokines, and extracellular vesicles and have the same biological effects as their parent cells. To face this cell-free regenerative therapy challenge, we have to clarify key strategy aspects, such as establishing tools that allow us a more precise diagnosis of aging frailty in order to identify the therapeutic requirements adapted to each case, identify the ideal type of MSC in the context of the functional heterogeneity of these cellular populations, to optimize the mass production and standardization of the primary materials (cells) and their secretome-derived products, to establish the appropriate methods to validate the anti-aging effects and to determine the most appropriate route of administration for each case.

Comparative Senescence and Lifespan

The word senescence is derived from the Latin word “senex” (meaning old). In biology, senescence is a process by which a cell ages and permanently stops dividing. Senescence is a natural universal phenomenon affecting all living organisms (e.g., humans, animals, and plants). It is the process of growing old (aging). The underlying mechanisms of senescence and aging at the cellular level are not fully understood. Senescence is a multifactorial process that can be induced by several stimuli including cellular stress, DNA damage, telomere shortening, and oncogene activation. The most popular theory to explain aging is the free radical theory. Senescence plays a role in the development of several age-related chronic diseases in humans (e.g., ischemic heart disease, osteoporosis, and cancer). Lifespan is a biological characteristic of every species. The lifespan of living organisms ranges from few hours (with mayfly) to potential eternity (with jellyfish and hydra). The maximum theoretical lifespan in humans is around 120 years. The lifespan in humans is influenced by multiple factors including genetic, epigenetic, lifestyle, environmental, metabolic, and endocrine factors. There are several ways to potentially extend the lifespan of humans and eventually surpass the maximum theoretical lifespan of 120 years. The tools that can be proposed include lifestyle, reduction of several life-threatening diseases and disabilities, hormonal replacement, antioxidants, autophagy inducers, senolytic drugs, stem cell therapy, and gene therapy.

Anti-Senescence Therapy

The development of therapeutic strategies aimed at the aging process of cells has attracted increasing attention in recent decades due to the involvement of this process in the development of many chronic and age-related diseases. Interestingly, preclinical studies have shown the success of a number of anti-aging approaches in the treatment of a range of chronic diseases. These approaches are directed against aging processes such as oxidative stress, telomerase shortening, inflammation, and deficient autophagy. Many strategies has been shown to be effective in delaying aging, including antiaging strategies based on establishing healthy lifestyle habits and pharmacological interventions aimed at disrupting senescent cells and senescent-associated secretory phenotype. Caloric restriction and intermittent fasting were reported to activate autophagy and reduce inflammation. In turn, immune-based strategies, senolytic agents, and senomorphics mediate their effects either by eliminating senescent cells through inducing apoptosis or by disrupting pathways by which senescent cells mediate their detrimental effects. In addition, given the association of the decline in the regenerative potential of stem cells with aging, many experimental and clinical studies indicate the effectiveness of stem cell transplantation in preventing or slowing the progress of age-related diseases by enhancing the repairing mechanisms and the secretion of many growth factors and cytokines.

Therapeutics effect of mesenchymal stromal cells in reactive oxygen species-induced damages

Reactive Oxygen Species are chemically unstable molecules generated during aerobic respiration, especially in the electron transport chain. ROS are involved in various biological functions; any imbalance in their standard level results in severe damage, for instance, oxidative damage, inflammation in a cellular system, and cancer. Oxidative damage activates signaling pathways, which result in cell proliferation, oncogenesis, and metastasis. Since the last few decades, mesenchymal stromal cells have been explored as therapeutic agents against various pathologies, such as cardiovascular diseases, acute and chronic kidney disease, neurodegenerative diseases, macular degeneration, and biliary diseases. Recently, the research community has begun developing several anti-tumor drugs, but these therapeutic drugs are ineffective. In this present review, we would like to emphasize MSCs-based targeted therapy against pathologies induced by ROS as cells possess regenerative potential, immunomodulation, and migratory capacity. We have also focused on how MSCs can be used as next-generation drugs with no side effects.

Mechanism of Action of Mesenchymal Stem Cells (MSCs): impact of delivery method

INTRODUCTION

Mesenchymal stromal cells (MSCs; AKA mesenchymal stem cells) stimulate healing and reduce inflammation. Promising therapeutic responses are seen in many late-phase clinical trials, but others have not satisfied their primary endpoints, making translation of MSCs into clinical practice difficult. These inconsistencies may be related to the route of MSC delivery, lack of product optimization, or varying background therapies received in clinical trials over time.

AREAS COVERED

Here we discuss the different routes of MSC delivery, highlighting the proposed mechanism(s) of therapeutic action as well as potential safety concerns. PubMed search criteria used: MSC plus: local administration; routes of administration; delivery methods; mechanism of action; therapy in different diseases.

EXPERT OPINION

Direct injection of MSCs using a controlled local delivery approach appears to have benefits in certain disease states, but further studies are required to make definitive conclusions regarding the superiority of one delivery method over another.

Mesenchymal stromal cells: Putative microenvironmental modulators become cell therapy

An exceptional safety profile has been shown in a large number of cell therapy clinical trials that use mesenchymal stromal cells (MSCs). However, reliable potency assays are still lacking to predict MSC immunosuppressive efficacy in the clinical setting. Nevertheless, MSCs are approved in Japan and Europe for the treatment of graft-versus-host and Crohn's fistular diseases, but not in the United States for any clinical indication. We discuss potential mechanisms of action for the therapeutic effects of MSC transplantation, experimental models that dissect tissue modulating function of MSCs, and approaches for identifying MSC effects in vivo by integrating biomarkers of disease and MSC activity.

Mesenchymal Stem Cell Transplantation for the Treatment of Age-Related Musculoskeletal Frailty

Projected life expectancy continues to grow worldwide owing to the advancement of new treatments and technologies leading to rapid growth of geriatric population. Thus, age-associated diseases especially in the musculoskeletal system are becoming more common. Loss of bone (osteoporosis) and muscle (sarcopenia) mass are conditions whose prevalence is increasing because of the change in population distribution in the world towards an older mean age. The deterioration in the bone and muscle functions can cause severe disability and seriously affects the patients’ quality of life. Currently, there is no treatment to prevent and reverse age-related musculoskeletal frailty. Existing interventions are mainly to slow down and control the signs and symptoms. Mesenchymal stem cell (MSC) transplantation is a promising approach to attenuate age-related musculoskeletal frailty. This review compiles the present knowledge of the causes and changes of the musculoskeletal frailty and the potential of MSC transplantation as a regenerative therapy for age-related musculoskeletal frailty.

Immunopathology and Immunosenescence, the Immunological Key Words of Severe COVID-19. Is There a Role for Stem Cell Transplantation?

The outcomes of Coronavirus disease-2019 (COVID-19) vary depending on the age, health status and sex of an individual, ranging from asymptomatic to lethal. From an immunologic viewpoint, the final severe lung damage observed in COVID-19 should be caused by cytokine storm, driven mainly by interleukin-6 and other pro-inflammatory cytokines. However, which immunopathogenic status precedes this "cytokine storm" and why the male older population is more severely affected, are currently unanswered questions. The aging of the immune system, i.e., immunosenescence, closely associated with a low-grade inflammatory status called "inflammageing," should play a key role. The remodeling of both innate and adaptive immune response observed with aging can partly explain the age gradient in severity and mortality of COVID-19. This review discusses how aging impacts the immune response to the virus, focusing on possible strategies to rejuvenate the immune system with stem cell-based therapies. Indeed, due to immunomodulatory and anti-inflammatory properties, multipotent mesenchymal stem cells (MSCs) are a worth-considering option against COVID-19 adverse outcomes.

Baseline pro-inflammatory gene expression in whole blood is related to adverse long-term outcomes after transcatheter aortic valve replacement: a case control study

BACKGROUND

Age-associated inflammation and immune system dysfunction have been implicated as mechanisms that increase risk for adverse long-term procedural outcomes in older adults. The purpose of this study was to investigate relationships between baseline inflammatory and innate antiviral gene expression and outcomes after transcatheter aortic valve replacement (TAVR) in older adults with severe aortic stenosis.

METHODS

We performed a retrospective case-control study comparing pre-procedural pro-inflammatory and Type 1 interferon (IFN) gene expression in 48 controls with favorable outcomes (alive 1 year after TAVR with improved quality of life [QoL]) versus 48 individuals with unfavorable outcomes (dead by 1 year or alive at 1 year but with reduced QoL). Gene expression was evaluated in whole blood via (1) pre-defined composite scores of 19 inflammation-associated genes and 34 Type I IFN response genes, and (2) pro-inflammatory and antiviral transcription factor activity inferred from promotor based bioinformatics analyses of genes showing > 25% difference in average expression levels across groups. All analyses were adjusted for age, gender, body mass index, diabetes, immunosuppression, cardiovascular disease (CVD), and frailty.

RESULTS

Relative to controls, those with unfavorable outcomes demonstrated higher expression of the pro-inflammatory gene composite prior to TAVR (p < 0.01) and bioinformatic indicators of elevated Nuclear Factor kB (p < 0.001) and Activator Protein 1 (p < 0.001) transcription factor activity, but no significant differences in Type I IFN-related gene expression.

CONCLUSIONS

These results demonstrate that a pro-inflammatory state prior to TAVR, independent of CVD severity and frailty status, is associated with worse long-term procedural outcomes.

Cardioprotective effects of transplanted adipose-derived stem cells under Ang II stress with Danggui administration augments cardiac function through upregulation of insulin-like growth factor 1 receptor in late-stage hypertension rats

In aging hypertensive conditions, deterioration of insulin-like growth factor 1 receptor (IGF1R) cause a pathological impact on hypertensive hearts with an increased Ang II level. Recovering these adverse conditions through transplanted adipose-derived stem cells is a challenging approach. Moreover, Danggui, a Traditional Chinese medicine (TCM), is used for the treatment of cardioprotective effects. In this study, to evaluate whether the combined effect of MSCs and TCM can recover the cardiac function in late-stage hypertension rats. We observed that lower dose of Danggui crude extract treatment showed an increased level of cell viability with maintained stemness properties and growth rate in rat adipose-derived stem cells (rADSCs). Further, we cocultured the H9c2 cells with rADSCs and the results revealed that Danggui-treated MSCs enhanced the IGF1R expression and attenuated the hypertrophy in H9c2 cells against Ang II challenge by immunoblot and rhodamine-phalloidin staining. In addition, Danggui crude extract was also quantified and characterized by HPLC and LC-MS analysis. Furthermore, the in vivo study was performed by considering 11 months old rats (n = 7). Importantly, the oral administration of Danggui crude extract with stem cells intravenous injection in SHR-D-ADSCs group showed a combination effect to augment the cardiac function through enhancement of ejection fraction, fractional shortening, contractility function in the late-stage hypertension conditions. We have also observed a decreased apoptosis rate in the heart tissue of SHR-D-ADSCs group. Taken together, these results indicate that the combinatorial effects of Danggui crude extract and stem cell therapy enhanced cardiac function in late-stage SHR rats.

Inflammation, a common mechanism in frailty and COVID19, and stem cells as a therapeutic approach

As our life expectancy increases, specific medical conditions appear, and new challenges are met in terms of global health. Frailty has become a medical and scientific concept to define pathologies where inflammation, depressed immune system, cellular senescence, and molecular aging converge. But more importantly, frailty is the ultimate cause of death that limits our life span and deteriorates health in an increasing proportion of the world population. The difficulty of tackling this problem is the combination of factors that influence frailty appearance, such as stem cells exhaustion, inflammation, loss of regeneration capability, and impaired immunomodulation. To date, multiple research fields have found mechanisms participating in this health condition, but to make progress, science will need to investigate frailty with an interdisciplinary approach. This article summarizes the current efforts to understand frailty from their processes mediated by inflammation, aging, and stem cells to provide a new perspective that unifies the efforts in producing advanced therapies against medical conditions in the context of frailty. We believe this approach against frailty is particularly relevant to COVID‐19, since people in a state of frailty die more frequently due to the hyperinflammatory process associated with this infection.

Potential of Mesenchymal Stem Cells in the Rejuvenation of the Aging Immune System

Rapid growth of the geriatric population has been made possible with advancements in pharmaceutical and health sciences. Hence, age-associated diseases are becoming more common. Aging encompasses deterioration of the immune system, known as immunosenescence. Dysregulation of the immune cell production, differentiation, and functioning lead to a chronic subclinical inflammatory state termed inflammaging. The hallmarks of the aging immune system are decreased naïve cells, increased memory cells, and increased serum levels of pro-inflammatory cytokines. Mesenchymal stem cell (MSC) transplantation is a promising solution to halt immunosenescence as the cells have excellent immunomodulatory functions and low immunogenicity. This review compiles the present knowledge of the causes and changes of the aging immune system and the potential of MSC transplantation as a regenerative therapy for immunosenescence.

Cardiac Mesenchymal Cells Cultured at Physiologic Oxygen Tension Have Superior Therapeutic Efficacy in Heart Failure Caused by Myocardial Infarction

Stem/progenitor cells are usually cultured at atmospheric O₂ tension (21%); however, since physiologic O₂ tension in the heart is ∼5%, using 21% O₂ may cause oxidative stress and toxicity. Cardiac mesenchymal cells (CMCs), a newly discovered and promising type of progenitor cells, are effective in improving left ventricle (LV) function after myocardial infarction (MI). We have previously shown that, compared with 21% O₂, culture at 5% O₂ increases CMC proliferation, telomerase activity, telomere length, and resistance to severe hypoxia in vitro. However, it is unknown whether these beneficial effects of 5% O₂in vitro translate into greater therapeutic efficacy in vivo in the treatment of heart failure. Thus, murine CMCs were cultured at 21% or 5% O₂. Mice with heart failure caused by a 60-min coronary occlusion followed by 30 days of reperfusion received vehicle, 21% or 5% O₂ CMCs via echocardiography-guided intraventricular injection. After 35 days, the improvement in LV ejection fraction effected by 5% O₂ CMCs was > 3 times greater than that afforded by 21% O₂ CMCs (5.2 vs. 1.5 units, P < 0.01). Hemodynamic studies (Millar catheter) yielded similar results both for load-dependent (LV dP/dt) and load-independent (end-systolic elastance) indices. Thus, two independent approaches (echo and hemodynamics) demonstrated the therapeutic superiority of 5% O₂ CMCs. Further, 5% O₂ CMCs, but not 21% O₂ CMCs, significantly decreased scar size, increased viable myocardium, reduced LV hypertrophy and dilatation, and limited myocardial fibrosis both in the risk and non-infarcted regions. Taken together, these results show, for the first time, that culturing CMCs at physiologic (5%) O₂ tension provides superior therapeutic efficacy in promoting cardiac repair in vivo. This concept may enhance the therapeutic potential of CMCs. Further, culture at 5% O₂ enables greater numbers of cells to be produced in a shorter time, thereby reducing costs and effort and limiting cell senescence. Thus, the present study has potentially vast implications for the field of cell therapy.

Application of mesenchymal stem cell therapy for aging frailty: from mechanisms to therapeutics

Aging frailty is a complex geriatric syndrome that becomes more prevalent with advancing age. It constitutes a major health problem due to frequent adverse outcomes. Frailty is characterized by disruption of physiological homeostasis and progressive decline of health status. Multiple factors contribute to development of frailty with advancing age, including genome instability, DNA damage, epigenetic alternations, stem cell exhaustion, among others. These interrelated factors comprehensively result in loss of tissue homeostasis and diminished reserve capacity in frailty. Therefore, the aged organism gradually represents symptoms of frailty with decline in physiological functions of organs. Notably, the brain, cardiovascular system, skeletal muscle, and endocrine system are intrinsically interrelated to frailty. The patients with frailty may display the diminished reserves capacity of organ systems. Due to the complex pathophysiology, no specific treatments have been approved for prevention of this syndrome. At such, effective strategies for intervening in pathogenic process to improve health status of frail patients are highly needed. Recent progress in cell-based therapy has greatly contributed to the amelioration of degenerative diseases related to age. Mesenchymal stem cells (MSCs) can exert regenerative effects and possess anti-inflammatory properties. Transplantation of MSCs represents as a promising therapeutic strategy to address the pathophysiologic problems of frail syndrome. Currently, MSC therapy have undergone the phase I and II trials in human subjects that have endorsed the safety and efficacy of MSCs for aging frailty. However, despite these positive results, caution is still needed with regard to potential to form tumors, and further large-scale studies are warranted to confirm the therapeutic efficacy of MSC therapy.

Therapeutic Properties of Mesenchymal Stromal/Stem Cells: The Need of Cell Priming for Cell-Free Therapies in Regenerative Medicine

Mesenchymal stromal/stem cells (MSCs) are multipotent adult stem cells that support homeostasis during tissue regeneration. In the last decade, cell therapies based on the use of MSCs have emerged as a promising strategy in the field of regenerative medicine. Although these cells possess robust therapeutic properties that can be applied in the treatment of different diseases, variables in preclinical and clinical trials lead to inconsistent outcomes. MSC therapeutic effects result from the secretion of bioactive molecules affected by either local microenvironment or MSC culture conditions. Hence, MSC paracrine action is currently being explored in several clinical settings either using a conditioned medium (CM) or MSC-derived exosomes (EXOs), where these products modulate tissue responses in different types of injuries. In this scenario, MSC paracrine mechanisms provide a promising framework for enhancing MSC therapeutic benefits, where the composition of secretome can be modulated by priming of the MSCs. In this review, we examine the literature on the priming of MSCs as a tool to enhance their therapeutic properties applicable to the main processes involved in tissue regeneration, including the reduction of fibrosis, the immunomodulation, the stimulation of angiogenesis, and the stimulation of resident progenitor cells, thereby providing new insights for the therapeutic use of MSCs-derived products.

Physiological Oxygen Tension Enhances Competence and Functional Properties of Murine Cardiac Mesenchymal Cells

Cardiac mesenchymal cells (CMCs), a newly-discovered and promising type of progenitor cells, are effective in improving cardiac function in rodents after myocardial infarction. Stem/progenitor cells are usually cultured at atmospheric O₂ tension (21%); however, the physiologic O₂ tension in the heart is ~5%, raising the concern that 21% O₂ may cause toxicity due to oxidative stress. Thus, we compared mouse CMCs cultured at 21% or 5% O₂ beginning at passage 2. At passage 5, CMCs underwent severe hypoxic stress (1% O₂ for 24 h). Compared with CMCs cultured at 21% O₂, culture at 5% O₂ consistently improved cell morphology throughout 5 passages, markedly decreased cell size, increased cell number, shortened cell doubling time, and dramatically reduced lactate dehydrogenase release from CMCs into culture media after hypoxic stress. Furthermore, culture at 5% O₂ increased telomerase activity and telomere length, implying that 21% O₂ tension impairs telomerase activity, resulting in telomere shortening and decreased cell proliferation. Thus far, almost all preclinical and clinical studies of cell therapy for the heart disease have used atmospheric (21%) O₂ to culture cells. Our data challenge this paradigm. Our results demonstrate that, compared with 21% O₂, 5% O₂ tension greatly enhances the competence and functional properties of CMCs. The increased proliferation rate at 5% O₂ means that target numbers of CMCs can be achieved with much less time and cost. Furthermore, since this increased proliferation may continue in vivo after CMC transplantation, and since cells grown at 5% O₂ are markedly resistant to severe hypoxic stress, and thus may be better able to survive after transplantation into scarred regions of the heart where O₂ is very low, culture at 5% O₂ may enhance the reparative properties of CMCs (and possibly other cell types). In conclusion, our data support a change in the methods used to culture CMCs and possibly other progenitor cells.

Mesenchymal Stem Cell Transplantation for the Treatment of Cognitive Frailty

As life expectancy increases, frailty and cognitive impairment have become major factors influencing healthy aging in elderly individuals. Frailty is a complicated clinical condition characterized by decreased physiological reserve and multisystem abnormalities. Cognitive frailty is a subtype of frailty that has aroused widespread concern among the scientific community and public health organizations. We herein review the pathogenesis of cognitive frailty, such as chronic inflammatory response, immunological hypofunction, imbalanced oxidative stress, reduced regenerative function, endocrine dysfunction, and energy metabolism disorder. Although existing interventions show some therapeutic effects, they do not meet the current clinical needs. To date, studies using stem cell technology for treating age-related diseases have achieved remarkable success. This suggests the possibility of applying stem cell treatment to cognitive frailty. We analyzed stem cell-based strategies for targeting anti-inflammation, antioxidation, regeneration, and immunoregulation using mesenchymal stem cells, as well as potential therapeutic targets for cognitive frailty. Based on this investigation, we propose a highly effective and low-cost stem cell-based replacement strategy. However, there is a lack of comprehensive research on the prospect of stem cell transplantation for improving cognitive frailty. In this review, we aim to provide the scientific background and a theoretical basis for testing cell therapy in future research.

Bone From Blood: Characteristics and Clinical Implications of Circulating Osteogenic Progenitor (COP) Cells

Circulating osteogenic progenitor (COP) cells are a population of cells in the peripheral blood with the capacity for bone formation, as well as broader differentiation into mesoderm-like cells in vitro. Although some of their biological characteristics are documented in vitro, their role in diseases of the musculoskeletal system remains yet to be fully evaluated. In this review, we provide an overview of the role of COP cells in a number of physiological and pathological conditions, as well as identify areas for future research. In addition, we suggest possible areas for clinical utilization in the management of musculoskeletal diseases. © 2020 American Society for Bone and Mineral Research (ASBMR).

Cryopreservation of Mesenchymal Stem Cells Using Medical Grade Ice Nucleation Inducer

Mesenchymal stem cells (MSCs) can differentiate into multiple different tissue lineages and have favourable immunogenic potential making them an attractive prospect for regenerative medicine. As an essential part of the manufacturing process, preservation of these cells whilst maintaining potential is of critical importance. An uncontrolled area of storage remains the rate of change of temperature during freezing and thawing. Controlled-rate freezers attempted to rectify this; however, the change of phase from liquid to solid introduces two extreme phenomena; a rapid rise and a rapid fall in temperature in addition to the intended cooling rate (normally -1 °C/min) as a part of the supercooling event in cryopreservation. Nucleation events are well known to initiate the freezing transition although their active use in the form of ice nucleation devices (IND) are in their infancy in cryopreservation. This study sought to better understand the effects of ice nucleation and its active instigation with the use of an IND in both a standard cryotube with MSCs in suspension and a high-throughput adhered MSC 96-well plate set-up. A potential threshold nucleation temperature for best recovery of dental pulp MSCs may occur around -10 °C and for larger volume cell storage, IND and fast thaw creates the most stable process. For adhered cells, an IND with a slow thaw enables greatest metabolic activity post-thaw. This demonstrates a necessity for a medical grade IND to be used in future regenerative medicine manufacturing with the parameters discussed in this study to create stable products for clinical cellular therapies.

Senescence in Pulmonary Fibrosis: Between Aging and Exposure

To date, chronic pulmonary pathologies represent the third leading cause of death in the elderly population. Evidence-based projections suggest that >65 (years old) individuals will account for approximately a quarter of the world population before the turn of the century. Genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication, are described as the nine “hallmarks” that govern cellular fitness. Any deviation from the normal pattern initiates a complex cascade of events culminating to a disease state. This blueprint, originally employed to describe aberrant changes in cancer cells, can be also used to describe aging and fibrosis. Pulmonary fibrosis (PF) is the result of a progressive decline in injury resolution processes stemming from endogenous (physiological decline or somatic mutations) or exogenous stress. Environmental, dietary or occupational exposure accelerates the pathogenesis of a senescent phenotype based on (1) window of exposure; (2) dose, duration, recurrence; and (3) cells type being targeted. As the lung ages, the threshold to generate an irreversibly senescent phenotype is lowered. However, we do not have sufficient knowledge to make accurate predictions. In this review, we provide an assessment of the literature that interrogates lung epithelial, mesenchymal, and immune senescence at the intersection of aging, environmental exposure and pulmonary fibrosis.

Frailty and the Risk of Polypharmacy in the Older Person: Enabling and Preventative Approaches

Frail older people have an inherent risk of polypharmacy due to the need to treat multiple comorbidities, thus leading to various negative effects on their health due to the adverse actions from the drugs. This issue was discussed from a person-centered perspective, highlighting the category of frail older adults who are at a higher risk. Appropriate medication reconciliation in this population with useful prescribing tools (Beers and START/STOPP criteria) to minimize polypharmacy and to provide alternative prescriptive intervention could go alongside primary care to reduce the extent of frailty and polypharmacy. Reducing delayed referrals and extended hospitalization with electronic health record systems and using the signs of frailty from the Electronic Frailty Index (EFI) to predict polypharmacy for frail older persons are preventative approaches that proactively respond to frailty associated with the risk of polypharmacy.

Altered physiology of mesenchymal stem cells in the pathogenesis of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis is the most common spinal deformity during puberty, especially in females. It is characterized by aberrant skeletal growth and generalized reduced bone density, which is associated with impaired bone mineral metabolism. Despite recent progress in multidisciplinary research to support various hypotheses, the pathogenesis of Adolescent idiopathic scoliosis is still not clearly understood. One of the hypothesis is to study the role of mesenchymal stem cells due to its involvement in the above-mentioned bone metabolic abnormalities. In this review, we will summarize reported literatures on the role of mesenchymal stem cells, particularly in the pathogenesis of Adolescent idiopathic scoliosis. In addition, we will describe the research on mesenchymal stem cells of Adolescent idiopathic scoliosis performed using bioinformatics tools.

Heart Failure and Adipose Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are considered a promising cell type for the treatment of heart failure (HF). In particular, MSCs in adipose tissue are being evaluated as an effective therapeutic tool. However, adipose MSCs are a major source of adipocyte generation and linked to obesity, which is an independent risk factor for HF. MSCs express all of the components of the renin-angiotensin system (RAS), which plays a pivotal role in the pathophysiology of HF. The local RAS also regulates MSC adipogenesis, indicating a connection between MSC-adipogenesis-obesity and HF. This review examines evidence of the complex relationship between HF and adipose MSCs and discusses how to explore this association for favorable therapeutic outcomes for HF.

Human umbilical cord mesenchymal stromal cells-derived extracellular vesicles exert potent bone protective effects by CLEC11A-mediated regulation of bone metabolism

Osteoporosis and osteoporotic fractures severely compromise quality of life in elderly people and lead to early death. Human umbilical cord mesenchymal stromal cell (MSC)-derived extracellular vesicles (hucMSC-EVs) possess considerable therapeutic effects in tissue repair and regeneration. Thus, in the present study, we investigated the effects of hucMSC-EVs on primary and secondary osteoporosis and explored the underlying mechanisms.

Methods: hucMSCs were isolated and cultured. EVs were obtained from the conditioned medium of hucMSCs and determined by using transmission electron microscopy, dynamic light scattering and Western Blot analyses. The effects of hucMSC-EVs on ovariectomy-induced postmenopausal osteoporosis and tail suspension-induced hindlimb disuse osteoporosis in mouse models were assessed by using microcomputed tomography, biomechanical, histochemical and immunohistochemical, as well as histomorphometric analyses. Proteomic analysis was applied between hucMSC-EVs and hucMSCs to screen the candidate proteins that mediate hucMSC-EVs function. The effects of hucMSC-EVs on osteogenic and adipogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs), and osteoclastogenesis of the macrophage cell line RAW264.7 in vitro were determined by using cytochemical staining and quantitative real-time PCR analysis. Subsequently, the roles of the key protein in hucMSC-EVs-induced regulation on BMSCs and RAW264.7 cells were evaluated.

Results: hucMSCs were able to differentiate into osteoblasts, adipocytes or chondrocytes and positively expressed CD29, CD44, CD73 and CD90, but negatively expressed CD34 and CD45. The morphological assessment revealed the typical cup- or sphere-shaped morphology of hucMSC-EVs with diameters predominantly ranging from 60 nm to 150 nm and expressed CD9, CD63, CD81 and TSG101. The systemic administration of hucMSC-EVs prevented bone loss and maintained bone strength in osteoporotic mice by enhancing bone formation, reducing marrow fat accumulation and decreasing bone resorption. Proteomic analysis showed that the potently pro-osteogenic protein, CLEC11A (C-type lectin domain family 11, member A) was very highly enriched in hucMSC-EVs. In addition, hucMSC-EVs enhanced the shift from adipogenic to osteogenic differentiation of BMSCs via delivering CLEC11A in vitro. Moreover, CLEC11A was required for the inhibitory effects of hucMSC-EVs on osteoclast formation.

Conclusion: Our results suggest that hucMSC-EVs serve as a critical regulator of bone metabolism by transferring CLEC11A and may represent a potential agent for prevention and treatment of osteoporosis.

Frailty and Rejuvenation with Stem Cells: Therapeutic Opportunities and Clinical Challenges

Frailty, one appealing target for improving successful aging of the elderly population, is a common clinical syndrome based on the accumulation of multisystemic function declines and the increase in susceptibility to stressors during biological aging. The age-dependent senescence, the frailty-related stem cell depletion, chronic inflammation, imbalance of immune homeostasis, and the reduction of multipotent stem cells collectively suggest the rational hypothesis that it is possible to (partially) cure frailty with stem cells. This systematic review has included all of the human trials of stem cell therapy for frailty from the main electronic databases and printed materials and screened the closely related reviews themed on the mechanisms of aging, frailty, and stem cells, to provide more insights in stem cell strategies for frailty, one promising method to recover health from a frail status. To date, a total of four trials about this subject have been registered on clinicaltrials.gov. The use of mesenchymal stem cells (MSCs), doses of 100 million cells, single peripheral intravenous infusion, follow-up periods of 6–12 months, and a focus primarily on safety and secondarily on efficacy are common characteristics of these studies. We conclude that intravenous infusion of allogenic MSCs is safe, well tolerated, and preliminarily effective clinically. More preclinical experiments and clinical trials are warranted to precisely elucidate the mechanism, safety, and efficacy of frailty stem cell therapy.