Health Span-Extending Activity of Human Amniotic Membrane- and Adipose Tissue-Derived Stem Cells in F344 Rats

Young Plasma Rejuvenates Blood DNA Methylation Profile, Extends Mean Lifespan, and Improves Physical Appearance in Old Rats

There is converging evidence that young blood conveys cells, vesicles, and molecules able to revitalize function and restore organ integrity in old individuals. We assessed the effects of young plasma on the lifespan, epigenetic age, and healthspan of old female rats. Beginning at 25.6 months of age, a group of 9 rats (group T) was intraperitoneally injected with plasma from young rats until their natural death. A group of 8 control rats of the same age received no treatment (group C). Blood samples were collected every other week. Survival curves showed that from age 26 to 30 months, none of the group T animals died, whereas the survival curve of group C rats began to decline at age 26 months. Blood DNAm age versus chronological age showed that DNAm age in young animals increased faster than chronological age, then slowed down, entering a plateau after 27 months. The DNAm age of the treated rats fell below the DNAm age of controls and, in numerical terms, remained consistently lower until natural death. When rats were grouped according to the similarities in their differential blood DNA methylation profile, samples from the treated and control rats clustered in separate groups. Analysis of promoter differential methylation in genes involved in systemic regulatory activities revealed specific GO term enrichment related to the insulin-like factors pathways as well as to cytokines and chemokines associated with immune and homeostatic functions. We conclude that young plasma therapy may constitute a natural, noninvasive intervention for epigenetic rejuvenation and health enhancement.

A systematic review of lifespan studies in rodents using stem cell transplantations

Organismal aging involves the progressive decline in organ function and increased susceptibility to age-associated diseases. Regardless of its origin, cellular aging is consequently reflected at the level of organ and associated systems dysfunction. Aging of stem cell populations within the body and their decreased ability to self-renew, differentiate, and regenerate damaged tissues, is a key contributor to organismal decline. Based on this, supplementing young stem cells may delay tissue aging, improve frailty and extend health and lifespan. This review investigates studies in rodents using stem cell transplantation from either mice or human donors. The aim is to consolidate available information on the efficacy of stem cell therapies in rodent models and provide insights to guide further research efforts. Out of the 21 studies included in this review, the methodology varied significantly including the lifespan measurement. To enable comparison the median lifespan was calculated using WebPlotDigitizer 4.6 if not provided by the literature. A total of 18 out of 21 studies evidenced significant lifespan extension post stem cell transplant, with 7 studies demonstrating benefits in reduced frailty and other aging complications.

Stem cells from human exfoliated deciduous teeth rejuvenate the liver in naturally aged mice by improving ribosomal and mitochondrial proteins

BACKGROUND AIMS

Aging is accompanied by a decline in cellular proteome homeostasis, mitochondrial, and metabolic function. Mesenchymal stromal cell (MSC) therapies have been reported to extend lifespan and delay some age-related pathologies, yet the anti-aging rate and mechanisms remain unclear. Here, we investigated the effects and mechanism by transplantation of stem cells from human exfoliated deciduous teeth (SHED) into the naturally aged mice model.

METHODS

SHED were cultured in vitro and injected into mice by caudal vein. The in vivo imaging uncovered that SHED labeled by DiR dye mainly migrated to the liver, spleen, and lung organs of wild-type mice. As the main metabolic organ and SHED homing place, the liver was selected for proteomics and aging clock algorithm (LiverClock) analysis, which was constructed to estimate the proteomic pattern related to liver age state.

RESULTS

After 6 months of continuous SHED injections, the liver proteomic pattern was reversed from senescent (∼30 months) to a youthful state (∼3 months), accompanied with upregulation of hepatocytes marker genes, anti-aging protein Klotho, a global improvement of liver functional pathways proteins, and a dramatic regulation of ribosomal and mitochondrial proteins, including upregulation of translation elongation and ribosome-sparing proteins Rpsa and Rplp0; elongation factors Eif4a1, Eef1b2, Eif5a; protein-folding chaperones Hsp90aa and Hspe1; ATP synthesis proteins Atp5b, Atp5o, Atp5j; and downregulation of most ribosomal proteins, suggesting that the proteome homeostasis destruction and mitochondria dysfunction in the aged mice liver might be relieved after SHED treatment.

CONCLUSIONS

SHED treatment could dramatically relieve the senescent state of the aged liver, affect ribosome component proteins and upregulate the ribosomal biogenesis proteins in the aged mice liver. These results may help understand the improvements and mechanisms of SHED treatment in anti-aging.

Intraocular Pressure-Lowering and Retina-Protective Effects of Exosome-Rich Conditioned Media from Human Amniotic Membrane Stem Cells in a Rat Model of Glaucoma

Glaucoma is one of the most devastating eye diseases, since the disease can develop into blindness and no effective therapeutics are available. Although the exact mechanisms and causes of glaucoma are unknown, increased intraocular pressure (IOP) has been demonstrated to be an important risk factor. Exosomes are lipid nanoparticles secreted from functional cells, including stem cells, and have been found to contain diverse functional molecules that control body function, inhibit inflammation, protect and regenerate cells, and restore damaged tissues. In the present study, exosome-rich conditioned media (ERCMs) were attained via hypoxic culture (2% O₂) of human amniotic membrane mesenchymal stem cells (AMMSCs) and amniotic membrane epithelial stem cells (AMESCs) containing 50 times more exosome particles than normoxic culture (20% O₂) medium (NCM). The exosome particles in ERCM were confirmed to be 77 nm in mean size and contain much greater amounts of growth factors (GFs) and neurotrophic factors (NFs) than those in NCM. The glaucoma-therapeutic effects of ERCMs were assessed in retinal cells and a hypertonic (1.8 M) saline-induced high-IOP animal model. CM-DiI-labeled AMMSC exosomes were found to readily penetrate the normal and H₂O₂-damaged retinal ganglion cells (RGCs), and AMMSC-ERCM not only facilitated retinal pigment epithelial cell (RPEC) proliferation but also protected against H₂O₂- and hypoxia-induced RPEC insults. The IOP of rats challenged with 1.8 M saline increased twice the normal IOP (12-17 mmHg) in a week. However, intravitreal injection of AMMSC-ERCM or AMESC-ERCM (3.9-4.5 × 10⁸ exosomes in 10 μL/eye) markedly recovered the IOP to normal level in 2 weeks, similar to the effect achieved with platelet-derived growth factor-AB (PDGF-AB, 1.5 μg), a reference material. In addition, AMMSC-ERCM, AMESC-ERCM, and PDGF-AB significantly reversed the shrinkage of retinal layers, preserved RGCs, and prevented neural injury in the glaucoma eyes. It was confirmed that stem cell ERCMs containing large numbers of functional molecules such as GFs and NFs improved glaucoma by protecting retinal cells against oxidative and hypoxic injuries in vitro and by recovering IOP and retinal degeneration in vivo. Therefore, it is suggested that stem cell ERCMs could be a promising candidate for the therapy of glaucoma.

Hematopoiesis during Ontogenesis, Adult Life, and Aging

In the bone marrow of vertebrates, two types of stem cells coexist-hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Hematopoiesis only occurs when these two stem cell types and their descendants interact. The descendants of HSCs supply the body with all the mature blood cells, while MSCs give rise to stromal cells that form a niche for HSCs and regulate the process of hematopoiesis. The studies of hematopoiesis were initially based on morphological observations, later extended by the use of physiological methods, and were subsequently augmented by massive application of sophisticated molecular techniques. The combination of these methods produced a wealth of new data on the organization and functional features of hematopoiesis in the ontogenesis of mammals and humans. This review summarizes the current views on hematopoiesis in mice and humans, discusses the development of blood elements and hematopoiesis in the embryo, and describes how the hematopoietic system works in the adult organism and how it changes during aging.

Stamina-Enhancing Effects of Human Adipose-Derived Stem Cells

Stamina-enhancing effects of human adipose derived stem cells (hADSCs) were investigated in young Sprague-Dawley rats. Ten-day-old male rats were transplanted intravenously (IV) or intracerebroventricularly (ICV) with hADSCs (1 × 10⁶ cells/rat), and physical activity was measured by locomotor activity and rota-rod performance at post-natal day (PND) 14, 20, 30, and 40, as well as a forced swimming test at PND 41. hADSCs injection increased the moving time in locomotor activity, the latency in rota-rod performance, and the maximum swimming time. For the improvement of physical activity, ICV transplantation was superior to IV injection. In biochemical analyses, ICV transplantation of hADSCs markedly reduced serum creatine phosphokinase, lactate dehydrogenase, alanine transaminase, and muscular lipid peroxidation, the markers for muscular and hepatic injuries, despite the reduction in muscular glycogen and serum triglycerides as energy sources. Notably, hADSCs secreted brain-derived neurotrophic factor (BDNF) and nerve growth factor in vitro, and increased the level of BDNF in the brain and muscles in vivo. The results indicate that hADSCs enhance physical activity including stamina not only by attenuating tissue injury, but also by strengthening the muscles via production of BDNF.

Comparison of Anti-Oxidative Effect of Human Adipose- and Amniotic Membrane-Derived Mesenchymal Stem Cell Conditioned Medium on Mouse Preimplantation Embryo Development

Oxidative stress is a major cause of damage to the quantity and quality of embryos produced in vitro. Antioxidants are usually supplemented to protect embryos from the suboptimal in vitro culture (IVC) environment. Amniotic membrane-derived mesenchymal stem cells (AMSC) have emerged as a promising regenerative therapy, and their paracrine factors with anti-oxidative effects are present in AMSC conditioned medium (CM). We examined the anti-oxidative potential of human AMSC-CM treatment during IVC on mouse preimplantation embryo development and antioxidant gene expression in the forkhead box O (FoxO) pathway. AMSC-CM (10%) was optimal for overall preimplantation embryo developmental processes and upregulated the expression of FoxOs and their downstream antioxidants in blastocysts (BL). Subsequently, compared to adipose-derived mesenchymal stem cell (ASC)-CM, AMSC-CM enhanced antioxidant gene expression and intracellular GSH levels in the BL. Total antioxidant capacity and SOD activity were greater in AMSC-CM than in ASC-CM. Furthermore, SOD and catalase were more active in culture medium supplemented with AMSC-CM than in ASC-CM. Lastly, the anti-apoptotic effect of AMSC-CM was observed with the regulation of apoptosis-related genes and mitochondrial membrane potential in BL. In conclusion, the present study established AMSC-CM treatment at an optimal concentration as a novel antioxidant intervention for assisted reproduction.

Umbilical Cord Cell Therapy Improves Spatial Memory in Aging Rats

There is a growing interest in the potential of adult stem cells for implementing regenerative medicine in the brain. We assessed the effect of intracerebroventricular (icv) administration of human umbilical cord perivascular cells (HUCPVCs) on spatial memory of senile (27 mo) female rats, using intact senile counterparts as controls. Approximately one third of the animals were injected in the lateral ventricles with a suspension containing 4.8 X 10⁵ HUCPVC in 8 μl per side. The other third received 4.8 X 10⁵ transgenic HUCPVC overexpressing Insulin-like growth factor-1 (IGF-1) and the last third of the rats received no treatment. Spatial memory performance was evaluated using a modified version of the Barnes maze test. In order to evaluate learning ability as well as spatial memory retention, we assessed the time spent (permanence) by animals in goal sector 1 (GS₁) and 3 (GS₃) when the escape box was removed. Fluorescence microscopy revealed the prescence of Dil-labeled HUCPVC in coronal sections of treated brains. The HUCPVC were located in close contact with the ependymal cells with only a few labeled cells migrating into the brain parenchyma. After treatment with naïve or IGF-1 transgenic HUCPVC, permanence in GS₁ and GS₃ increased significantly whereas there were no changes in the intact animals. We conclude that HUCPVC injected icv are effective to improve some components of spatial memory in senile rats. The ready accessibility of HUCPVC constitutes a significant incentive to continue the exploration of their therapeutic potential on neurodegenerative diseases.

Human Neural Stem Cells Encoding ChAT Gene Restore Cognitive Function via Acetylcholine Synthesis, Aβ Elimination, and Neuroregeneration in APPswe/PS1dE9 Mice.Int J Mol Sci. 2020;21. [PMID: 32486466 DOI: 10.3390/ijms21113958]

In Alzheimer disease (AD) patients, degeneration of the cholinergic system utilizing acetylcholine for memory acquisition is observed. Since AD therapy using acetylcholinesterase (AChE) inhibitors are only palliative for memory deficits without slowing or reversing disease progress, there is a need for effective therapies, and stem cell-based therapeutic approaches targeting AD should fulfill this requirement. We established a human neural stem cell (NSC) line encoding choline acetyltransferase (ChAT) gene, an acetylcholine-synthesizing enzyme. APPswe/PS1dE9 AD model mice transplanted with the F3.ChAT NSCs exhibited improved cognitive function and physical activity. Transplanted F3.ChAT NSCs in the AD mice differentiated into neurons and astrocytes, produced ChAT protein, increased the ACh level, and improved the learning and memory function. F3.ChAT cell transplantation reduced Aβ deposits by recovering microglial function; i.e., the down-regulation of β-secretase and inflammatory cytokines and up-regulation of Aβ-degrading enzyme neprilysin. F3.ChAT cells restored growth factors (GFs) and neurotrophic factors (NFs), and they induced the proliferation of NSCs in the host brain. These findings indicate that NSCs overexpressing ChAT can ameliorate complex cognitive and physical deficits of AD animals by releasing ACh, reducing Aβ deposit, and promoting neuroregeneration by the production of GFs/NFs. It is suggested that NSCs overexpressing ChAT could be a candidate for cell therapy in advanced AD therapy.

Neuroprotective effects of human neural stem cells over-expressing choline acetyltransferase in a middle cerebral artery occlusion model

Stroke is one of the most-devastating brain diseases causing acute death or permanent disability. Although tissue-type plasminogen activator was approved by Food and Drug Administration for early reperfusion of the occluded vessels, oxidative injury may cause extensive brain infarction. Accordingly, there is a need for effective neuroprotection during reperfusion, and stem cell-based therapeutic approaches should fulfill this requirement. We established human neural stem cells (NSCs) encoding gene of choline acetyltransferase (F3.ChAT), an acetylcholine-synthesizing enzyme, and investigated whether infusion of the F3.ChAT cells attenuate the ischemia-reperfusion brain damage in a rat model of middle cerebral artery occlusion (MCAO). F3.ChAT cells were found to produce much higher amounts of ChAT as well as neuroprotective and anti-inflammatory neurotrophins than their parental F3 NSCs. After 2-h occlusion, the artery was reperfused, along with intravenous infusion of the stem cells (1 × 10⁶ cells/rat). Administration of the F3.ChAT cells markedly reduced the infarction volume and improved both the cognitive dysfunction and behavioural deficits of MCAO animals, in which F3.ChAT cells were superior to F3 cells. F3.ChAT cells not only restored microtubule-associated protein-2, a neuronal cytoskeletal protein, and preserved microvessels, but also suppressed lipid peroxidation, pro-inflammatory cytokines, glial fibrillary acidic protein, and intercellular adhesion molecule-1 in the brain tissues. The results demonstrate that early intravenous infusion of NSCs expressing ChAT and neurotrophins attenuate brain and capillary injuries and restore neurobehavioural functions via neuroprotective and anti-inflammatory activities, and that F3.ChAT cells could be a candidate for the neuroprotection and functional recovery of acute stroke patients.

How Could We Slow or Reverse the Human Aging Process and Extend the Healthy Life Span with Heterochronous Autologous Hematopoietic Stem Cell Transplantation

The senescence of the immune system contributes considerably to the age-related diseases that are the main causes of death after the age of 65. In this study, we present an appealing option for the prevention of immune senescence and slowing or reversing the aging process, which can be achieved by heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow stem cells are collected from donors while young, cryopreserved and stored for a long period, and reinfused at a later time when indicated. After reinfusion and homing, these young HSCs could participate in normal hemato- and immunopoiesis and improve several immune functions by expanding the immune- as well as hematopoietic cell repertoire. Several animal studies have already confirmed the feasibility of this procedure, which extended the longevity of the treated animals. If translated to human medicine, haHSCT could prevent or mitigate age-related immune defects and extend the healthy life span. In this review, we describe the concept of haHSCT, recent studies that confirm its feasibility, and discuss the further research needed to translate this heterochronous methodology.

Extension of Maximal Lifespan and High Bone Marrow Chimerism After Nonmyeloablative Syngeneic Transplantation of Bone Marrow From Young to Old Mice

The goal of this work was to determine the effect of nonablative syngeneic transplantation of young bone marrow (BM) to laboratory animals (mice) of advanced age upon maximum duration of their lifespan. To do this, transplantation of 100 million nucleated cells from BM of young syngeneic donors to an old nonablated animal was performed at the time when half of the population had already died. As a result, the maximum lifespan (MLS) increased by 28 ± 5%, and the survival time from the beginning of the experiment increased 2.8 ± 0.3-fold. The chimerism of the BM 6 months after the transplantation was 28%.

Mesenchymal stem cell therapy improves spatial memory and hippocampal structure in aging rats

There is a growing interest in the potential of mesenchymal stem cells (MSCs) for implementing regenerative medicine in the brain as they have shown neurogenic and immunomodulatory activities. We assessed the effect of intracerebroventricular (icv) administration of human bone marrow-derived MSCs (hBM-MSCs) on spatial memory and hippocampal morphology of senile (27 months) female rats, using 3-months-old counterparts as young controls. Half of the animals were injected in the lateral ventricles (LV) with a suspension containing 5 × 10⁵hBM-MSCs in 8 μl per side. The other half received no treatment (senile controls). Spatial memory performance was assessed with a modified version of the Barnes maze test. We employed one probe trial, one day after training in order to evaluate learning ability as well as spatial memory retention. Neuroblast (DCX) and microglial (Iba-1 immunoreactive) markers were also immunohistochemically quantitated in the animals by means of an unbiased stereological approach. In addition, hippocampal presynaptic protein expression was assessed by immunoblotting analysis. After treatment, the senile MSC-treated group showed a significant improvement in spatial memory accuracy and extended permanence in a one- and 3-hole goal sectors as compared with senile controls. The MSC treatment increased the number of neuroblasts in the hippocampal dentate gyrus, reduced the number of reactive microglial cells, and restored presynaptic protein levels as compared to senile controls. We conclude that icv injected hBM-MSCs are effective in improving spatial memory in senile rats and that the strategy improves some functional and morphologic brain features typically altered in aging rats.

Improvement by Human Oligodendrocyte Progenitor Cells of Neurobehavioral Disorders in an Experimental Model of Neonatal Periventricular Leukomalacia

The effects of human oligodendrocyte progenitor (F3.olig2) cells on improving neurobehavioral deficits were investigated in an experimental model of periventricular leukomalacia (PVL). Seven-day-old male rats were subjected to hypoxia-ischemia-lipopolysaccharide injection (HIL), and intracerebroventricularly transplanted with F3.olig2 (4 × 10⁵ cells/rat) once at post-natal day (PND) 10 or repeatedly at PND10, 17, 27, and 37. Neurobehavioral disorders were evaluated at PND14, 20, 30, and 40 via cylinder test, locomotor activity, and rotarod performance, and cognitive function was evaluated at PND41-45 through passive avoidance and Morris water-maze performances. F3.olig2 cells recovered the rate of use of the forelimb contralateral to the injured brain, improved locomotor activity, and restored rotarod performance of PVL animals; in addition, marked improvement of learning and memory function was seen. It was confirmed that transplanted F3·olig2 cells migrated to injured areas, matured to oligodendrocytes expressing myelin basic protein (MBP), and markedly attenuated the loss of host MBP in the corpus callosum. The results indicate that the transplanted F3.olig2 cells restored neurobehavioral functions by preventing axonal demyelination, and that human oligodendrocyte progenitor cells could be a candidate for cell therapy of perinatal hypoxic-ischemic and infectious brain injuries including PVL and cerebral palsy.

The potential of non-myeloablative heterochronous autologous hematopoietic stem cell transplantation for extending a healthy life span

Aging is a complex multifactorial process, a prominent component being the senescence of the immune system. Consequently, immune-related diseases develop, including atherosclerosis, cancer, and life-threatening infections, which impact on health and longevity. Rejuvenating the aged immune system could mitigate these diseases, thereby contributing to longevity and health. Currently, an appealing option for rejuvenating the immune system is heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow/peripheral blood stem cells are collected during the youth of an individual, cryopreserved, and re-infused when he or she has reached an older age. After infusion, young hematopoietic stem cells can reconstitute the compromised immune system and improve immune function. Several studies using animal models have achieved substantial extension of the life span of animals treated with haHSCT. Therefore, haHSCT could be regarded as a potential procedure for preventing age-related immune defects and extending healthy longevity. In this review, the pros, cons, and future feasibility of this approach are discussed.

Conditioned medium derived from rat amniotic epithelial cells confers protection against inflammation, cancer, and senescence

Amniotic epithelial cells (AECs) are a class of fetal stem cells that derives from the epiblast and resides in the amnion until birth. AECs are suitable candidates for regenerative medicine because of the ease of collection, their low immunogenicity and inability to form tumors after transplantation. Even though human AECs have been widely investigated, the fact remains that very little is known about AECs isolated from rat, one of the most common animal models in medical testing. In this study, we showed that rat AECs retained stemness properties and plasticity, expressed the pluripotency markers Sox2, Nanog, and Oct4 and were able to differentiate toward the osteogenic lineage. The addition of conditioned medium collected from rat AECs to lipopolysaccharide-activated macrophages elicited anti-inflammatory properties through a decrease of Tnfa expression and slowed tumor cell proliferation in vitro and in vivo. The senescence-associated secretory phenotype was also significantly lower upon incubation of senescent human IMR-90 fibroblast cells with conditioned medium from rat AECs. These results confirm the potential of AECs in the modulation of inflammatory mechanisms and open new therapeutic possibilities for regenerative medicine and anti-aging therapies as well.

Application of Stem Cell Technology in Antiaging and Aging-Related Diseases

Stem cells are one kind of cells that have the potential of proliferation and differentiation. The human beings are originated from a totipotential stem cell-fertilized egg. After birth, the proliferation and differentiation of stem cells contribute to the development and maturation of individual tissues and organs. After maturation, aging is a phases of the life process, the stem cells within the individual's tissues ensure the metabolism of different cells and tissues, such as the hematopoietic stem cells in the bone marrow, which ensure there are still enough red blood cells (RBCs) being responsible for the mission of transporting oxygen after a single RBC has completed its 120-day physiological life cycle. After pathological damage and necrosis occurring on the intestinal epithelial cells or tubular epithelial cells, there will be regenerative epithelial cells continuing to maintain the integrity of the structure and function of the intestine and renal tubules. The role of stem cells in the regeneration and repair of tissues and organs is not only because of the ability of proliferation and differentiation of stem cells but also of the secretion function of stem cells, which secrete various growth factors and cytokines to regulate the tissue microenvironment. For example, mesenchymal stem cells derived from bone marrow are important regulators in bone marrow hematopoietic stem cell niche. Mesenchymal stem cells maintain the "stemness" of hematopoietic stem cells by secreting various cytokines.Aging is a phases of the life process, and all creatures obey this rule of nature. Different organs of the body have different time of entering into aging. Aging is reflected in structural changes and reduced function. Among them, the reduction of regeneration and repair capacity is the main feature of aging. As we age, the aging of stem cells in human tissues is a major cause of the decline in tissue regeneration capacity. Therefore, the elderly's ability of regenerate and repair can be improved by application of advance stem cell technology. It can delay the aging process and treat aged diseases (showed in Fig. 16.1).

Advances in Therapeutic Approaches to Extend Healthspan: a perspective from the 2nd Scripps Symposium on the Biology of Aging

The 2^nd Scripps Florida Symposium on The Biology of Aging entitled ‘Advances in Therapeutic Approaches to Extend Healthspan’ was held on January 22^nd–25^th, 2017 at The Scripps Research Institute in Jupiter, Florida. The meeting highlighted a variety of therapeutic approaches in animal models of aging that either are or soon will be in clinic trials. For example, drugs targeting senescent cells, metformin, rapalogs, NAD precursors, young plasma, mitochondrial‐targeted free radical scavengers, stem cells, and stem cell factors all have shown significant preclinical efficacy. This perspective, based on presentations and discussions at the symposium, outlines the current and future state of development of therapeutic approaches to extend human healthspan.

mTOR signaling plays a critical role in the defects observed in muscle-derived stem/progenitor cells isolated from a murine model of accelerated aging

Mice expressing reduced levels of ERCC1-XPF (Ercc1^-/Δ mice) demonstrate premature onset of age-related changes due to decreased repair of DNA damage. Muscle-derived stem/progenitor cells (MDSPCs) isolated from Ercc1^-/Δ mice have an impaired capacity for cell differentiation. The mammalian target of rapamycin (mTOR) is a critical regulator of cell growth in response to nutrient, hormone, and oxygen levels. Inhibition of the mTOR pathway extends the lifespan of several species. Here, we examined the role of mTOR in regulating the MDSPC dysfunction that occurs with accelerated aging. We show that mTOR signaling pathways are activated in Ercc1^-/Δ MDSPCs compared with wild-type (WT) MDSPCs. Additionally, inhibiting mTOR with rapamycin promoted autophagy and improved the myogenic differentiation capacity of the Ercc1^-/Δ MDSPCs. The percent of apoptotic and senescent cells in Ercc1^-/Δ MDSPC cultures was decreased upon mTOR inhibition. These results establish that mTOR signaling contributes to stem cell dysfunction and cell fate decisions in response to endogenous DNA damage. Therefore, mTOR represents a potential therapeutic target for improving defective, aged stem cells. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1375-1382, 2017.

Inhibition of NF-κB improves the stress resistance and myogenic differentiation of MDSPCs isolated from naturally aged mice

A decline in the regenerative capacity of adult stem cells with aging is well documented. As a result of this decline, the efficacy of autologous stem cell therapies is likely to decline with increasing donor age. In these cases, strategies to restore the function of aged stem cells would have clinical utility. Globally, the transcription factor NF-κB is up-regulated in aged tissues. Given the negative role that NF-κB plays in myogenesis, we investigated whether the age-related decline in the function of muscle-derived stem/progenitor cells (MDSPCs) could be improved by inhibition of NF-κB. Herein, we demonstrate that pharmacologic or genetic inhibition of NF-κB activation increases myogenic differentiation and improves resistance to oxidative stress. Our results suggest that MDSPC “aging” may be reversible, and that pharmacologic targeting of pathways such as NF-κB may enhance the efficacy of cell-based therapies.

Amniotic Epithelial Cells: A New Tool to Combat Aging and Age-Related Diseases?

The number of elderly people is growing at an unprecedented rate and this increase of the aging population is expected to have a direct impact on the incidence of age-related diseases and healthcare-associated costs. Thus, it is imperative that new tools are developed to fight and slow age-related diseases. Regenerative medicine is a promising strategy for the maintenance of health and function late in life; however, stem cell-based therapies face several challenges including rejection and tumor transformation. As an alternative, the placenta offers an extraordinary source of fetal stem cells, including the amniotic epithelial cells (AECs), which retain some of the characteristics of embryonic stem cells, but show low immunogenicity, together with immunomodulatory and anti-inflammatory activities. Because of these characteristics, AECs have been widely utilized in regenerative medicine. This perspective highlights different mechanisms triggered by transplanted AECs that could be potentially useful for anti-aging therapies, which include: Graft and differentiation for tissue regeneration in age-related settings, anti-inflammatory behavior to combat “inflammaging,” anti-tumor activity, direct lifespan and healthspan extension properties, and possibly rejuvenation in a manner reminiscent of heterochronic parabiosis. Here, we critically discuss benefits and limitation of AECs-based therapies in age-related diseases.

A Rat Treated with Mesenchymal Stem Cells Lives to 44 Months of Age

There is a growing interest in the potential of mesenchymal stem cells (MSCs) for implementing regenerative medicine. We assessed the effect of intravenous administration of human bone marrow-derived MSC on the life span of a single Sprague-Dawley female rat. The treatment was started when the rat was 6 months old and the cells were administered every 2 weeks afterward. The treatment did not induce any obvious changes in body growth or behavior and the rat showed the typical age changes for this strain, except that, unlike intact counterparts, the animal did not develop mammary tumors or pituitary gland hyperplasia. The more remarkable effect of the treatment was on life span, which was 44 months compared with an average of 36 months for intact laboratory rats. We conclude that despite the low N value, it is likely that the MSC treatment was responsible for the exceptionally long survival of the rat. The potential rewards of confirming the present findings warrant further studies involving higher N values.