to post #1, Step 3:
[quote]
3) in vitro human and mouse old and young cell culturing on young and old blood serum medium, respectively, and with stem cells provided environments; that is co-culturing, like in [Sci2], with the goal to create an ideal environment, like medium, etc. for optimization of the cell culturing to achieve and maintain the good health and proliferation capacity of the cells. Like reducing the oxidative stress, defending the cell and DNA integrity and the telomere lengths, etc.. One example: [Sci6]. ...
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Another example for this:
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Wnt/β-Catenin Signaling Induces the Aging of Mesenchymal Stem Cells through the DNA Damage Response and the p53/p21 Pathway
PLoS One. 2011;6(6):e21397. doi: 10.1371/journal.pone.0021397. Epub 2011 Jun 21.
Zhang DY, Wang HJ, Tan YZ.
Department of Anatomy and Histology and Embryology, Shanghai Medical College of Fudan University, Shanghai, People's Republic of China.
http://www.ncbi.nlm....pubmed/21712954
free full: http://www.plosone.o...al.pone.0021397
Abstract
Recent studies have demonstrated the importance of cellular extrinsic factors in the aging of adult stem cells. However, the effects of an aged cell-extrinsic environment on mesenchymal stem cell (MSC) aging and the factors involved remain unclear. In the current study, we examine the effects of old rat serum (ORS) on the aging of MSCs, and explore the effects and mechanisms of Wnt/β-catenin signaling on MSC aging induced by ORS treatment. Senescence-associated changes in the cells are examined with SA-β-galactosidase staining and ROS staining. The proliferation ability is detected by MTT assay. The surviving and apoptotic cells are determined using AO/EB staining. The results suggest that ORS promotes MSC senescence and reduces the proliferation and survival of cells. The immunofluorescence staining shows that the expression of β-catenin increases in MSCs of old rats. To identify the effects of Wnt/β-catenin signaling on MSC aging induced with ORS, the expression of β-catenin, GSK-3β, and c-myc are detected. The results show that the Wnt/β-catenin signaling in the cells is activated after ORS treatment. Then we examine the aging, proliferation, and survival of MSCs after modulating Wnt/β-catenin signaling. The results indicate that the senescence and dysfunction of MSCs in the medium containing ORS is reversed by the Wnt/β-catenin signaling inhibitor DKK1 or by β-catenin siRNA. Moreover, the expression of γ-H2A.X, a molecular marker of DNA damage response, p16(INK4a), p53, and p21 is increased in senescent MSCs induced with ORS, and is also reversed by DKK1 or by β-catenin siRNA. In summary, our study indicates the Wnt/β-catenin signaling may play a critical role in MSC aging induced by the serum of aged animals and suggests that the DNA damage response and p53/p21 pathway may be the main mediators of MSC aging induced by excessive activation of Wnt/β-catenin signaling.
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This study is especially interesting because it suggests that cell signaling can cause (if improper) DNA damage and also can initiate DNA repair.
[quote]
Wnt/β-catenin signaling induces the aging of mesenchymal stem cells through promoting the ROS production
Mol Cell Biochem. 2013 Feb;374(1-2):13-20. doi: 10.1007/s11010-012-1498-1. Epub 2012 Nov 3.
Zhang DY, Pan Y, Zhang C, Yan BX, Yu SS, Wu DL, Shi MM, Shi K, Cai XX, Zhou SS, Wang JB, Pan JP, Zhang LH.
Department of Basic Medicine, School of Medicine and Life Sciences, Zhejiang University City College, 51 Huzhou Street, Hangzhou, 310015, People's Republic of China.
http://www.ncbi.nlm....pubmed/23124852
Abstract
Recent studies have demonstrated that the Wnt/β-catenin signaling plays an important role in stem cell aging. However, the mechanisms of cell senescence induced by Wnt/β-catenin signaling are still poorly understood. Our preliminary study has indicated that activated Wnt/β-catenin signaling can induce MSC aging. In this study, we reported that the Wnt/β-catenin signaling was a potent activator of reactive oxygen species (ROS) generation in MSCs. After scavenging ROS with N-acetylcysteine, Wnt/β-catenin signaling-induced MSC aging was significantly attenuated and the DNA damage and the expression of p16(INK4A), p53, and p21 were reduced in MSCs. These results indicated that the Wnt/β-catenin signaling could induce MSC aging through promoting the intracellular production of ROS, and ROS may be the main mediators of MSC aging induced by excessive activation of Wnt/β-catenin signaling.
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Another study about aged serum and Wnt:
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Aging increases CCN1 expression leading to muscle senescence
Am J Physiol Cell Physiol. 2013 Nov 6.
Du J, Klein JD, Hassounah F, Zhang J, Zhang C, Wang XH.
Beijing Institute of Heart Lung & Blood Vessel Diseases.
http://www.ncbi.nlm....pubmed/24196529
Abstract
Using microarray analysis, we found that aging sarcopenia is associated with a sharp increase in the mRNA of the matricellular protein CCN1 (Cyr61/CTGF/Nov). CCN1 mRNA was up-regulated 113-fold in muscle of aged versus young rats. CCN1 protein was increased in aging muscle in both rats (2.8-fold) and mice (3.8-fold). When muscle progenitor cells (MPCs) were treated with recombinant CCN1, cell proliferation was decreased but there was no change in the myogenic marker myoD. However, the CCN1 treated MPCs did express a senescence marker (SA-βgal). Interestingly, we found CCN1 increased p53, p16Ink4A and pRP (hypophosphorylated retinoblastoma protein) protein levels, all of which can arrest cell growth in MPCs. When MPCs were treated with aged rodent serum CCN1 mRNA increased by 7-fold and protein increased by 3-fold suggesting the presence of a circulating regulator. Therefore, we looked for a circulating regulator. Wnt-3a, a stimulator of CCN1 expression, was increased in serum from elderly humans (2.6-fold) and aged rodents (2.0-fold) compared with young controls. We transduced C2C12 myoblasts with wnt-3a and found that CCN1 protein was increased in a time and dose dependent manner. We conclude that in aging muscle, the circulating factor, wnt-3a, acts to increase CCN1 expression, prompting muscle senescence by activating cell arrest proteins.
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about aging, muscle and Wnt:
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Increased Wnt signaling during aging alters muscle stem cell fate and increases fibrosis
Science. 2007 Aug 10;317(5839):807-10.
Brack AS, Conboy MJ, Roy S, Lee M, Kuo CJ, Keller C, Rando TA.
Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
http://www.ncbi.nlm....pubmed/17690295
Abstract
The regenerative potential of skeletal muscle declines with age, and this impairment is associated with an increase in tissue fibrosis. We show that muscle stem cells (satellite cells) from aged mice tend to convert from a myogenic to a fibrogenic lineage as they begin to proliferate and that this conversion is mediated by factors in the systemic environment of the old animals. We also show that this lineage conversion is associated with an activation of the canonical Wnt signaling pathway in aged myogenic progenitors and can be suppressed by Wnt inhibitors. Furthermore, components of serum from aged mice that bind to the Frizzled family of proteins, which are Wnt receptors, may account for the elevated Wnt signaling in aged cells. These results indicate that the Wnt signaling pathway may play a critical role in tissue-specific stem cell aging and an increase in tissue fibrosis with age.
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on aged fibroblasts and young ECM:
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Restoration of senescent human diploid fibroblasts by modulation of the extracellular matrix
Aging Cell. 2011 Feb;10(1):148-57. doi: 10.1111/j.1474-9726.2010.00654.x.
Choi HR, Cho KA, Kang HT, Lee JB, Kaeberlein M, Suh Y, Chung IK, Park SC.
Department of Biochemistry and Molecular Biology, Aging and Apoptosis Research Center, Institute on Aging, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-799, South Korea.
http://www.ncbi.nlm....pubmed/21108727
free full: http://onlinelibrary...10.00654.x/full
Abstract
Human diploid fibroblasts have the capacity to complete a finite number of cell divisions before entering a state of replicative senescence characterized by growth arrest, changes in morphology, and altered gene expression. Herein, we report that interaction with extracellular matrix (ECM) from young cells is sufficient to restore aged, senescent cells to an apparently youthful state. The identity of the restored cells as having been derived from senescent cells has been confirmed by a variety of methods, including time lapse live cell imaging and DNA finger print analysis. In addition to cell morphology, phenotypic restoration was assessed by resumption of proliferative potential, growth factor responsiveness, reduction of intracellular reactive oxygen species levels, recovery of mitochondrial membrane potential, and increased telomere length. Mechanistically, we find that both Ku and SIRT1 are induced during restoration and are required for senescent cells to return to a youthful phenotype. These observations demonstrate that human cellular senescence is profoundly influenced by cues from the ECM, and that senescent cell plasticity is much greater than that was previously believed to be the case.
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young stem cell environment:
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Rejuvenation of chondrogenic potential in a young stem cell microenvironment
Biomaterials. 2014 Jan;35(2):642-53. doi: 10.1016/j.biomaterials.2013.09.099. Epub 2013 Oct 19.
Li J, Hansen KC, Zhang Y, Dong C, Dinu CZ, Dzieciatkowska M, Pei M.
Stem Cell and Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University, PO Box 9196, One Medical Center Drive, Morgantown, WV 26506, USA; Department of Exercise Physiology, West Virginia University, Morgantown, WV 26506, USA.
http://www.ncbi.nlm....pubmed/24148243
Abstract
Autologous cells suffer from limited cell number and senescence during ex vivo expansion for cartilage repair. Here we found that expansion on extracellular matrix (ECM) deposited by fetal synovium-derived stem cells (SDSCs) (FE) was superior to ECM deposited by adult SDSCs (AE) in promoting cell proliferation and chondrogenic potential. Unique proteins in FE might be responsible for the rejuvenation effect of FE while advantageous proteins in AE might contribute to differentiation more than to proliferation. Compared to AE, the lower elasticity of FE yielded expanded adult SDSCs with lower elasticity which could be responsible for the enhancement of chondrogenic and adipogenic differentiation. MAPK and noncanonical Wnt signals were actively involved in ECM-mediated adult SDSC rejuvenation.
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***
this is to the cardiac / heart system, the topic of post #25:
in that the Torella et al. 2004 study: "Cardiac stem cell and myocyte aging, heart failure, and insulin-like growth factor-1 overexpression" described various conditions of heart aging and the effects of IGF-1 overexpression on cardiac stem cell senescence; some more informations to this and its effect on lifespan, as in theory it may have some life extension result.
[quote]
The influence of disease and age on human cardiac stem cells
Ann Clin Biochem. 2013 Nov 6.
Hu S, Yan G, He W, Liu Z, Xu H, Ma G.
Department of Cardiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China.
http://www.ncbi.nlm....pubmed/24197835
Abstract
Recent studies have found that cardiac stem cells (CSCs) are present in the adult heart. CSCs play an important role in maintaining the balance of the number of myocardial cells. The purpose of this study was to examine characteristics of human CSCs and their correlation with clinical characteristics of patients. We collected heart auricles of 105 patients (age range, 1-78 years; mean, 55.6 +- 17.0 years) undergoing cardiac surgery to obtain CSCs. We assayed the percentage of c-kit positive (c-kit+) CSCs with flow cytometry. Plasma NE-(carboxymethyl)lysine (CML) concentrations were measured by enzyme-linked immunosorbent assay. The percentage of c-kit+ CSCs was 4.96 +- 3.12% (0.98-17.17%), and this was significantly negatively correlated with age, the presence of diabetes mellitus (DM) and coronary heart disease (CHD) (r values were -0.797 [P < 0.01], -0.500 [P < 0.01] and -0.250 [P = 0.011], respectively). The percentage of c-kit+ CSCs was significantly negatively correlated with CML concentrations (r = -0.859, P < 0.01). The percentage of c-kit+ CSCs decreases with ageing and is further decreased in patients with DM and/or CHD. Furthermore, plasma CML concentrations may have potential as an indicator of the number of c-kit+ CSCs.
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[quote]
Activation of cardiac progenitor cells reverses the failing heart senescent phenotype and prolongs lifespan
Circ Res. 2008 Mar 14;102(5):597-606. doi: 10.1161/CIRCRESAHA.107.165464. Epub 2008 Jan 17.
Gonzalez A, Rota M, Nurzynska D, Misao Y, Tillmanns J, Ojaimi C, Padin-Iruegas ME, Müller P, Esposito G, Bearzi C, Vitale S, Dawn B, Sanganalmath SK, Baker M, Hintze TH, Bolli R, Urbanek K, Hosoda T, Anversa P, Kajstura J, Leri A.
Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
http://www.ncbi.nlm....pubmed/18202313
free full: http://circres.ahajo.../102/5/597.long
Abstract
Heart failure is the leading cause of death in the elderly, but whether this is the result of a primary aging myopathy dictated by depletion of the cardiac progenitor cell (CPC) pool is unknown. Similarly, whether current lifespan reflects the ineluctable genetic clock or heart failure interferes with the genetically determined fate of the organ and organism is an important question. We have identified that chronological age leads to telomeric shortening in CPCs, which by necessity generate a differentiated progeny that rapidly acquires the senescent phenotype conditioning organ aging. CPC aging is mediated by attenuation of the insulin-like growth factor-1/insulin-like growth factor-1 receptor and hepatocyte growth factor/c-Met systems, which do not counteract any longer the CPC renin-angiotensin system, resulting in cellular senescence, growth arrest, and apoptosis. However, pulse-chase 5-bromodeoxyuridine-labeling assay revealed that the senescent heart contains functionally competent CPCs that have the properties of stem cells. This subset of telomerase-competent CPCs have long telomeres and, following activation, migrate to the regions of damage, where they generate a population of young cardiomyocytes, reversing partly the aging myopathy. The senescent heart phenotype and heart failure are corrected to some extent, leading to prolongation of maximum lifespan.
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[quote]
Cardiac-specific overexpression of insulin-like growth factor 1 attenuates aging-associated cardiac diastolic contractile dysfunction and protein damage.
Am J Physiol Heart Circ Physiol. 2007 Mar;292(3):H1398-403. Epub 2006 Nov 3.
Li Q, Wu S, Li SY, Lopez FL, Du M, Kajstura J, Anversa P, Ren J.
Div of Pharmaceutical Science & Center for Cardiovascular Research and Alternative Medicine, Univ of Wyoming, Laramie, WY 82071-3375, USA.
http://www.ncbi.nlm....pubmed/17085535
free full: http://ajpheart.phys...92/3/H1398.long
Abstract
Aging is associated with hepatic growth hormone resistance resulting in a fall in serum insulin-like growth factor 1 (IGF-1) level. However, whether loss of IGF-1 contributes to cardiac aging is unclear. This study was designed to examine the effect of cardiac overexpression of IGF-1 on cardiomyocyte contractile function in young (3 mo) and old (26-28 mo) mice. Cardiomyocyte contractile function was evaluated, including peak shortening (PS), time to 90% PS, time to 90% relengthening (TR(90)), and maximal velocity of shortening/relengthening (+/-dL/dt). Levels of advanced glycation end product, protein carbonyl, sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), phospholamban, and Na(+)/Ca(2+) exchanger were assessed by Western blot analysis. SERCA activity was measured by (45)Ca(2+) uptake. Aging induced a decline in plasma IGF-1 levels. Aged cells exhibited depressed +/-dL/dt, prolonged TR(90), and a steeper PS decline in response to increasing stimulus frequency compared with those in young myocytes. IGF-1 transgene alleviated aging-induced loss in plasma IGF-1 and aging-induced mechanical defects with little effect in young mice. The beneficial effect of IGF-1 transgene on aging-associated cardiomyocyte contractile dysfunction was somewhat mimicked by short-term in vitro treatment of recombinant IGF-1 (500 nM). Advanced glycation end product and protein carbonyl levels were higher in aged mice, which were not affected by IGF-1. Expression of SERCA2a (but not Na(+)/Ca(2+) exchanger and phospholamban) and SERCA activity were reduced with aging, which was ablated by the IGF-1 transgene. Collectively, our data suggest a beneficial role of IGF-1 in aging-induced cardiac contractile dysfunction, possibly related to improved Ca(2+) uptake.
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[quote]
Influence of cardiac-specific overexpression of insulin-like growth factor 1 on lifespan and aging-associated changes in cardiac intracellular Ca2+ homeostasis, protein damage and apoptotic protein expression
Aging Cell. 2007 Dec;6(6):799-806. Epub 2007 Oct 30.
Li Q, Ren J.
Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA.
http://www.ncbi.nlm....pubmed/17973971
free full: http://onlinelibrary...07.00343.x/full
Abstract
A fall in circulating levels of cardiac survival factor insulin-like growth factor 1 (IGF-1) contributes to cardiac aging. To better understand the role of IGF-1 in cardiac aging, we examined the influence of cardiac IGF-1 overexpression on lifespan, cardiomyocyte intracellular Ca2+ homeostasis, protein damage, apoptosis and expression of pro- and anti-apoptotic proteins in young and old mice. Mouse survival rate was constructed by the Kaplan-Meier curve. Intracellular Ca2+ was evaluated by fura-2 fluorescence. Protein damage was determined by protein carbonyl formation. Apoptosis was assessed by caspase-8 expression, caspase-3 and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) assay. Pro- and anti-apoptotic proteins including Bax, p53, pp53, Bcl2, Omi/HtrA2, apoptosis repressor with caspase recruitment domain (ARC) and X-linked inhibitor of apoptosis protein (XIAP) were assessed by Western blot. Aging decreased plasma in IGF-1 levels, elevated myocyte resting intracellular Ca2+ levels, reduced electrically stimulated rise in intracellular Ca2+ and delayed intracellular Ca2+ decay associated with enhanced protein carbonyl formation, caspase-8 expression and caspase-3 activity in FVB mice, all of which with the exception of elevated resting intracellular Ca2+ were attenuated by IGF-1. Aging up-regulated expression of Bax, Bcl2 and ARC, down-regulated XIAP expression and did not affect p53, pp53 and Omi/HtrA2. The IGF-1 transgene attenuated or nullified aging-induced changes in Bax, Bcl2 and XIAP. Our data suggest a beneficial role for IGF-1 in aging-induced survival, cardiac intracellular Ca2+ homeostasis, protein damage and apoptosis possibly related to pro- and anti-apoptotic proteins.
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The graph of the effect on lifespan:
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Figure 1. Cumulative survival curve (Kaplan–Meier survival plot) of male FVB and IGF-1 mice. The cumulative survival rate was plotted against age in days. Log-rank test was performed to compare the FVB and IGF-1 lines (P = 0.026) (n = 39 and 38 mice for FVB and IGF-1 mice, respectively).
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The result is about 23 %. (see the Note on humans below).
Some text from this study:
[quote]
...
Discussion
Our present study revealed that cardiac-specific overexpression of IGF-1 significantly prolonged lifespan, rescued aging-induced intracellular Ca2+ homeostasis, protein damage and apoptosis in cardiomyocytes. The IGF-1-induced protection against cardiac aging may be associated with attenuation of aging-induced changes in Bax, Bcl2 and XIAP proteins. Furthermore, cardiac-specific IGF-1 overexpression attenuated aging-induced declines in plasma IGF-1 levels. As IGF-1 itself did not significantly affect intracellular Ca2+ homeostasis, tissue protein damage or apoptosis in young mouse hearts, its beneficial role against aging-induced cardiac defect indicates clinical potential for this growth factor in delaying the cardiac aging process and minimizing senescence-associated high cardiovascular mortality.
...
First, our data revealed that IGF-1 is capable of alleviating aging-induced cardiac protein damage and apoptosis. Enhanced oxidative damage and apoptosis may directly interrupt cardiac intracellular Ca2+ homeostasis and excitation–contraction coupling (Chien, 1999; Goldhaber & Qayyum, 2000). Second, we found that IGF-1 significantly attenuated aging-induced changes in Bax, Bcl2 and XIAP, but not in p53, pp53 and Omi/HtrA2, indicating involvement of both pro- and anti-apoptotic proteins in IGF-1-induced protection. Generally speaking, few mouse deaths are attributable to heart failure.
...
IGF-1 participates in the regulation of tissue remodeling, glucose metabolism, insulin sensitivity, lipid profile, myocardial growth and myocardial function in both physiological and pathophysiological conditions (Ren et al., 1999; Delafontaine & Brink, 2000; Lombardi et al., 2000). A fall in the serum IGF-1 level, which often accompanies the biological aging process, leads to abnormal body composition and metabolism (Paolisso et al., 1997).
...
In conclusion, our study revealed that cardiac-specific overexpression of IGF-1 rescues aging-induced intracellular Ca2+ homeostasis possibly through protected protein damage and apoptosis. Our data also revealed potential involvement of anti-apoptotic proteins in IGF-1-elicited cardioprotective effects against cardiac aging. These data should shed some light on the clinical application of IGF-1 in the treatment of aging-associated cardiac dysfunction.
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Note for humans: in mice heart dysfunction, cf. 2nd paragraph of the Discussion section of the last study, quoted above, is not so prominent cause as it is in humans, cf. e.g. the Gonzalez et al. 2008 study (the 2nd article above: "Activation of cardiac progenitor cells..."). So in the case of humans a similar treatment may have more profound effect on lifespan. Also the quantity level of the singnaling molecules may result in different life extension in both (and other) species.
