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I.R.F. / Aging news / Cloning

This section displays information and article reviews about use of cloning in aging.

May 16, 2023 Therapeutic Cloning. Critical Reprogramming Factors in Human MII Oocytes are Physically Associated with the Chromosomes?
Cytoplasmic factors present in mature, metaphase II (MII) arrested oocytes have a unique ability to reset the identity of transplanted somatic cell nuclei to the embryonic state. Since the initial discovery in amphibians, somatic cell nuclear transfer (SCNT) success in a range of different mammalian species has demonstrated that such reprogramming activity in enucleated or spindle-free oocytes (cytoplasts) is universal. However, despite numerous applications of SCNT for animal cloning, the nature of reprogramming oocyte factors and their mechanism of action remain largely unknown … [find out more >>]
April 29, 2023 Intranasal Administration of MSC after Neonatal Stroke
Brain injury caused by stroke is a frequent cause of perinatal morbidity and mortality with limited therapeutic options. Mesenchymal stem cells (MSC) have been shown to improve outcome after neonatal hypoxic-ischemic brain injury mainly by secretion of growth factors stimulating repair processes. It was investigated whether MSC treatment improves recovery after neonatal stroke and whether MSC overexpressing brain-derived neurotrophic factor (MSC-BDNF) further enhances recovery … [find out more >>]
April 11, 2023 Human Glia Enhance Activity-dependent Plasticity and Learning in Mice
The unique processing capabilities of the human brain reflect a number of evolutionary adaptations by its cellular constituents. One especially distinct feature of the adult human brain's cellular composition is the size and complexity of its astrocytic cohort. Human astrocytes are both morphologically and functionally distinct from those of infraprimate mammals, in that human astroglia are larger and exhibit far greater architectural complexity and cellular pleomorphism, as well as more rapid syncytial calcium signaling, than their murine counterparts … [find out more >>]
March 25, 2023 Modified Monkey Cells and Cancer Therapy
Attempts to increase the antigenicity and immunogenicity of tumors have been made for more than 20 years. These modifications can be achieved by introducing allogeneic major histocompatibility complex molecules, cytokine genes, viruses, or costimulatory molecules such as B7-1 and B7-2 into tumor cells. Numerous studies in different tumor and mouse models have established that the transfection of cytokine genes such as interleukin-2 (IL-2), IL-4, IL-7, IL-10, IL-12, GM-CSF, or interferon-gamma (IFN-gamma) into tumor cell lines can protect mice against inoculation with these modified autologous cells … [find out more >>]
June 22, 2022 MicroRNAs as Cancer Therapeutics
Dysregulation of miRNAs appears to play a fundamental role in the onset, progression and dissemination of many cancers, and replacement of down regulated miRNAs in tumor cells results in a positive therapeutic response. Thus, in theory, inhibition of a particular miRNA linked to cancer onset or progression can remove the inhibition of the translation of a therapeutic protein - and conversely, administration of a miRNA mimetic can boost the endogenous miRNA population repressing the translation of an oncogenic protein … [find out more >>]
February 29, 2022 RNA-binding Proteins and Aging
Gene expression patterns vary dramatically in a tissue-specific and age-dependent manner. RNA-binding proteins that regulate mRNA turnover and/or translation (TTR-RBPs) critically affect the subsets of expressed proteins. However, very little is known regarding the tissue- and age-dependent expression of TTR-RBPs in humans … [find out more >>]
October 28, 2011 Communication of Mesenchymal and Embryonic Stem Cells. Who Could Drive Hematopoesis?
The realization of human embryonic stem cells (hESC) as a model for human developmental hematopoiesis and in potential cell replacement strategies relies on an improved understanding of the extrinsic and intrinsic factors regulating hematopoietic-specific hESC differentiation. Human mesenchymal stem cells (hMSCs) are multipotent cells of mesodermal origin that form part of hematopoietic stem cell niches and have an important role in the regulation of hematopoiesis through production of secreted factors and/or cell-to-cell interactions … [find out more >>]
October 27, 2011 Safety and Complications on the Re-implantation of Culture-Expanded Mesenchymal Stem Cells
Mesenchymal stem cells (MSCs) hold great promise as therapeutic agents in regenerative medicine. Numerous animal studies have documented the multipotency of MSCs, showing their capabilities for differentiating into orthopedic tissues such as muscle, bone, cartilage, and tendon. However, the safety of culture expanded MSC's for human use has only just begun to be reported … [find out more >>]
July 14, 2011 Ku Protein and the Link to Telomere Deletion
The repair of DNA double-strand breaks (DSBs) is important for cellular survival, the maintenance of genomic integrity, and the prevention of tumorigenesis. DSBs can be caused by exposure to exogenous agents, including ionizing radiation and chemotherapeutic agents, and be generated by endogenous mechanisms, such as variable (diversity) joining [V(D)J] and class-switch recombination processes required for the maturation of B and T lymphocytes. Moreover, the ends of linear chromosomes present cells with naturally occurring DSBs i.e., telomeres – and these must be regulated to ensure the stable maintenance of the genome. … [find out more >>]
June 27, 2011 Estrogen Deficiency or Over-activity May Cause Ovarian Tissue Aging or Tumorigenesis
Estrogen is implicated as playing an important role in aging and tumorigenesis of estrogen responsive tissues; however the mechanisms underlying the mitogenic actions of estrogen are not fully understood. Scientists found that estrogen deficiency in mice caused by targeted disruption of the aromatase gene results in a significant inhibition of telomerase maintenance of telomeres in mouse ovaries in a tissue-specific manner. The inhibition entails a significant shortening of telomeres and compromised proliferation in the follicular granulosa cell compartment of ovary. … [find out more >>]
January 18, 2011 MSC Proliferation due to Donor Age
The aim of this study was to investigate the biological characteristics of human bone marrow mesenchymal stem cells from bone marrow of different age donors. The experiments were divided into four groups by donors age: fetus, 0-20 years old, 20-40 years old and older than 40 years respectfully … [find out more >>]
November 26, 2010 Human CD34+ Cells Can Fuse with Hepatocytes in Mice
Several studies have shown that hepatocytes can be generated from hematopoietic stem cells, but this event is believed to be rare and to require hepatic damage. To investigate this phenomenon in human cells, scientists used a NOD/SCID/gamma(c)null (NOG) mouse model that can achieve a tremendously high level of chimerism when transplanted with human hematopoietic cells. … [find out more >>]
November 17, 2010 Cord Blood Could Be Useful in Treatment of Stroke and Neural Injury
Embryonic stem (ES) cell therapies are often promoted as the optimal stem cell source for regenerative medicine applications because of their ability to develop into any tissue in the body. Unfortunately, ES cell applications are currently limited by ethical, political, biological and regulatory hurdles. However, multipotent non-ES cells are available in large numbers in umbilical cord blood (CB). CB stem cells are capable of giving rise to hematopoietic, epithelial, endothelial and neural tissues both in vitro and in vivo. Thus, CB stem cells are amenable to treat a wide variety of diseases including cardiovascular, ophthalmic, orthopaedic, neurological and endocrine diseases. In addition, the recent use of CB in several regenerative medicine clinical studies has demonstrated its pluripotent nature … [find out more >>]
October 21, 2010 Length of Parent Telomeres is Important in Offspring Generations
Scientists have studied models of telomerase haploinsufficiency in humans and mice to analyze regulation of telomere length and the significance of "set points" in inheritance of telomere length. In three families with clinical syndromes associated with short telomeres resulting from haploinsufficient mutations in TERT, the gene encoding telomerase reverse transcriptase, they wondered whether restoration of normal genotypes in offspring of affected individuals would elongate inherited short telomeres … [find out more >>]
August 26, 2010 MicroRNA and Induction of Pluripotence
The discovery of microRNAs (miRNAs - small non-coding RNAs of approximately 22 nt) heralded a new and exciting era in biology. During this period miRNAs have gone from ignominy due to their origin mainly in 'junk DNA' to notoriety where they can be at once characterized as being all powerful (a single miRNA can target and potentially silence several hundred genes) and yet marginal (a given gene can be targeted by several miRNAs such that a given miRNA typically exerts a modest repression). The emerging paradox is exemplified by miRNAs that are prominently expressed in embryonic stem (ES) cells … [find out more >>]
July 30, 2010 Micro RNA and Cell Senescence
Endothelial progenitor cells (EPCs) play an important role in angiogenesis, which is essential for numerous physiological processes as well as tumor growth. Several microRNAs (miRNAs) have been reported to be involved in angiogenesis. MiR-34a, recently reported as a tumor suppressor, has been found to target silent information regulator 1 (Sirt1), leading to cell cycle arrest or apoptosis. However, the role of miR-34a in EPC-mediated angiogenesis was unknown … [find out more >>]
June 30, 2010 Result of Coculture of Stem Cells with Adult Articular Chondrocytes
Human embryonic stem (hES) cells have been suggested as a cell source for the repair of cartilage lesions. Scientists studied how coculture with human articular chondrocytes affects the expansion potential, morphology, expression of surface markers, and differentiation abilities of hES cells, with special regard to chondrogenic differentiation … [find out more >>]
May 21, 2010 Artificial Neural Tissue from Human Umbilical Cord Blood
Stem cell-based regenerative neurology is an emerging concept for treatment of diseases of central nervous system. Among variety of proposed procedures, one of the most promising is refilling of cystic cavities of injured brain parenchyma with artificial neural tissue. Recent studies revealed that after allogenic transplantation in rodents these tissue-engineered entities were shown efficient in repair of hypoxic/ischemic brain injury … [find out more >>]
May 17, 2010 Fibroblasts from Gingiva Show Strong Immuno-modulatory Action in Mice
Aside from the well-established self-renewal and multipotent differentiation properties, mesenchymal stem cells exhibit both immunomodulatory and anti-inflammatory roles in several experimental autoimmune and inflammatory diseases. Scientists isolated a new population of stem cells from human gingiva, a tissue source easily accessible from the oral cavity, namely, gingiva-derived mesenchymal stem cells (GMSCs), which exhibited clonogenicity, self-renewal, and multipotent differentiation capacities … [find out more >>]
April 30, 2010 Vitamin D Importance in Organism Aging
Vitamin D inadequacy is common worldwide and classically causes osteomalacia and rickets. More recently, the contribution of low vitamin D status to increased falls and fracture risk has become appreciated. Additionally, nonclassic effects of vitamin D inadequacy are being recognized, and low vitamin D status is being potentially associated with a multitude of conditions (including Alzheimer disease, osteoarthritis, multiple sclerosis, and hypertension) and higher overall mortality. More detailed analysis has revealed molecular regulatory properties of this important substance … [find out more >>]
April 28, 2010 Recipient Chimerism after Bone Marrow Transplantation
Bone marrow contains stem cells with the potential to differentiate into mature cells of various organs. Scientists determined whether circulating stem cells have a similar potential … [find out more >>]
April 27, 2010 Bone Marrow Cell Dissemination in Lethally Irradiated Mice. Long Term Study
Bone marrow (BM) cells are considered the source of stem cells for various organs. However, how quickly BM cells can penetrate and constitute lymphoid organs remains elusive. In the present study, scientists addressed this issue in a model using genetically-labeled syngeneic BM transplantation (BMT) … [find out more >>]
March 31, 2010 Human Placental Extract Heals Menopausal Symptoms and Fatigue
In Korea, human placental extract (HPE) has recently been used to treat various diseases (chronic liver diseases, menopause syndrome, chronic fatigue, skin pigment diseases, etc.), but evidence-based studies are not yet sufficient. The aim of this study was to examine the effects of HPE on menopausal symptoms, fatigue, and risk factors for cardiovascular disease in middle-aged Korean women in a randomized controlled trial. … [find out more >>]
March 30, 2010 Role of Placental Extract in Chronic Wound Healing
The objective of the study was to investigate the effect of topical placental extract in the treatment of non-healing wounds. For this purpose 100 patients attending the wound clinic with wounds of more than six weeks duration were recruited. 50 patients were treated with placental extract, and 50 were controls. … [find out more >>]
March 15, 2010 Cartilage Repair by Muscle-derived Stem Cells
Muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle exhibit long-time proliferation, high self-renewal, and multipotent differentiation. This study was undertaken to investigate the ability of MDSCs that were retrovirally transduced to express bone morphogenetic protein 4 (BMP-4) to differentiate into chondrocytes in vitro and in vivo and enhance articular cartilage repair … [find out more >>]
January 29, 2010 Klotho Gene Transfection for Renal Damage Repair
Klotho is a recently discovered antiaging gene. The objective of this study was to test the hypothesis that Klotho gene delivery attenuates the progression of spontaneous hypertension and renal damage in spontaneous hypertensive rats (SHRs) … [find out more >>]
January 26, 2010 Artificial Cartilage From Stem Cells
The production of engineered cartilage from mesenchymal stem cells is a rapidly developing field. By use of autologous cells and various scaffolds lots of promising results have been achieved … [find out more >>]
January 19, 2010 Mesenchymal Cells in Wound Healing
The nonhematopoietic component of bone marrow includes multipotent mesenchymal stem cells (MSC) capable of differentiating into fat, bone, muscle, cartilage, and endothelium. Here scientists describe the cell culture and characterization, delivery system, and successful use of topically applied autologous MSC to accelerate the healing of human and experimental murine wounds … [find out more >>]
November 30, 2009 Connective Tissue Growth Factor in Wound Healing
Tissues lose mechanical integrity when our body is injured. To rapidly restore mechanical stability a multitude of cell types can jump into action by acquiring a reparative phenotype-the myofibroblast. These cytoskeletal features not only enable the myofibroblast to remodel and contract the extracellular matrix but to adapt its activity to changes in the mechanical microenvironment … [find out more >>]
November 9, 2009 Cloning Procedure and Sub-chromosomal Mutations
The mechanisms that have evolved to maintain genome stability during cell cycle progression are challenged when a somatic cell nucleus is placed in a meiotic environment such as the ooplasm. Chromosomal spindle aberrations ensue in the majority of reconstructed oocytes within 2 hours of transplantation, but it is not known if they recover or persist with the onset of embryonic divisions … [find out more >>]
September 23, 2009 Novel Players in Tissue Regeneration
Bone marrow (BM) was, for many years, primarily envisioned as the "home organ" of hematopoietic stem cells (HSC). Augmenting evidence demonstrates, however, that BM, in addition to HSC, also contains a heterogeneous population of non-HSC … [find out more >>]
August 10, 2009 Cloning Technique For Old Animals
Senescent mice are often infertile, and the cloning success rate decreases with age, making it almost impossible to produce cloned progeny directly from such animals. Scientists have tried to produce offspring from such "unclonable" senescent mice using nuclear transfer techniques … [find out more >>]
August 7, 2009 Alzheimer's Disease in Mice
Senescence-accelerated mice (SAMP8) serve as a model for Alzheimer's disease (AD) as they exhibit early loss of memory and increased amyloid precursor protein (APP) expression … [find out more >>]
September 15, 2008 Insulin-like Growth Factor I Receptor Mutations in Centenarians
Rather than being a passive, haphazard process of wear and tear, lifespan can be modulated actively by components of the insulin/insulin-like growth factor I (IGFI) pathway in laboratory animals … [find out more >>]
July 14, 2008 Mesenchymal Stem Cells and Kidney Repair
Mesenchymal stem cells (MSC) were recently shown to migrate to injured tissues when transplanted systemically. The mechanisms underlying the migration and homing of these cells is, however, unclear … [find out more >>]
July 11, 2008 Stem Cells and Kidney Repair
The susceptibility of developing acute renal failure depends on the ability of the kidney to recover from acute injury and regain normal function. Recently, the possible contribution of stem cells (SCs) to the regeneration of acute tubular injury has been investigated. … [find out more >>]
April 18, 2008 Postmitotic Aging of Fibroblasts and Inhibition of Proteasome by Lipofuscin and Ceroid
Cellular aging can be studied at two different levels: either as proliferative senescence, i.e., the loss of reproductive ability of a nontransformed cell culture; or as aging, and finally death, of individual (postmitotic) cells … [find out more >>]
April 17, 2008 The Telomere and Telomerase Connection to Aging and Cancer
The ends of linear eukaryotic chromosomes contain specialized structures called telomeres. Human telomeres consist of tandem repetitive arrays of the hexameric sequence TTAGGG, with overall telomere sizes ranging from ~15 kb at birth to sometimes 55 kb in chronic disease states. The telomeric repeats help maintain chromosomal integrity and provide a buffer of potentially expendable DNA. … [find out more >>]
April 1, 2008 Brain Injury and Stem Cells
Traumatic brain injury (TBI) causes extensive loss of cerebral parenchyma; however, no strategy for reconstruction has been clinically effective. Scientists have used human marrow stromal cells (hMSCs) to treat rats subjected to TBI and found no significant changes in the lesion volume, although functional outcome was improved significantly. To identify new ways of delivering hMSCs into the injured brain and to maximize the therapeutic benefits of hMSC treatment, they investigated the use of collagen scaffolds implanted with hMSCs as a cell delivery system for treatment of TBI … [find out more >>]
February 19, 2008 Hepatic Progenitors – the Promising Stem Cells?
As it remains unknown whether the normal adult liver contains bipotent stem/progenitor cells, and if it does, then what are the circumstances under which they proliferate. It was the objective to clarify whether the normal adult liver contains hepatic stem/progenitor cells, and if it does, will they be activated by extensive hepatectomy? … [find out more >>]
December 14, 2007 Embryonic Cells and their Ability to Differentiate into Endothelial-like and Smooth Muscle-like Cells
Tissue engineering is a perspective part of body sculpturing especially when this body ages. If discard all ethical issues embryonic cells are the best candidates here. … [find out more >>]
December 13, 2007 Selegiline – a Novel Differentiation Factor for Neural Lineage Cells
The antiaging effect of selegiline was reported by several investigators; therefore, there is a growing interest in the potential use of stem cell therapy in aging. In this investigation, selegiline was used to induce neuronal differentiation in undifferentiated pluripotent embryonic stem cells (ESCs). … [find out more >>]
November 14, 2007 Super Mice after Gene Therapy
Transgenic mice, containing a chimeric gene in which the cDNA for phosphoenolpyruvate carboxykinase (GTP) (PEPCK-C) (EC [EC] 2) was linked to the α-skeletal actin gene promoter, express PEPCK-C in skeletal muscle (1-3 units/g). Breeding two founder lines together produced mice with an activity of PEPCK-C of 9 units/g of muscle (PEPCK-Cmus mice) … [find out more >>]
October 23, 2007 Erythropoietic Properties Of Stem Cells
Erythropoietic repopulating abilities of fetal liver cells and young and old adult marrow cells were compared as follows: equal numbers of cells from a donor of each age were mixed with a constant portion of cells pooled from genetically distinguishable competitors. These mixtures were transplanted into stem cell-depleted recipients, and the proportions of recipient hemoglobin that were donor type measured the relative effectiveness of early erythropoietic precursor cells from the various donors. At intervals of 3-6 months, recipients were sublethally irradiated, requiring a new round of competitive repopulation … [find out more >>]
October 22, 2007 Fetal Stem Cells Repopulating Abilities Are Higher For Long Term Periods
Multilineage precursor cells from 14-day B6 (C57B1/6J) mouse fetal liver and adult bone marrow that repopulate both the lymphoid and myeloid systems were compared by competitive repopulation … [find out more >>]
October 19, 2007 Are Old Marrow Cells The Best In Repopulating The Recipients?
It is possible that erythropoietic stem cells do not age. This would mean that stem cells from old donors can function as well as those from young or fetal donors … [find out more >>]
July 17, 2007 MSC and Cartilage Engineering
Adult cartilage tissue has limited self-repair capacity, especially in the case of severe damages caused by developmental abnormalities, trauma, or aging-related degeneration like osteoarthritis. Adult mesenchymal stem cells (MSCs) have the potential to differentiate into cells of different lineages including bone, cartilage, and fat … [find out more >>]
July 16, 2007 Adult Mesenchymal Cells
Adult mesenchymal stem cells (MSCs) can be isolated from bone marrow or marrow aspirates and because they are culture-dish adherent, they can be expanded in culture while maintaining their multipotency … [find out more >>]
July 10, 2007 Human Neural Stem Cells in Stroke Treatment
Intracerebral hemorrhage (ICH) is a lethal stroke type. As mortality approaches 50%, and current medical therapy against ICH shows only limited effectiveness, an alternative approach is required, such as stem cell-based cell therapy. … [find out more >>]
June 30, 2007 Cell Therapy and Donor Age
Scientists have evaluated the impact of donor age on the efficacy of myocardial cellular therapy for ischemic cardiomyopathy. Smooth muscle cells from old donors retain their ability to improve cardiac function after implantation into ischemic myocardium. … [find out more >>]
June 15, 2007 Mesenchymal Stem Cells and their Properties
New evidence suggests that the artery wall is a recipient and source of MSCs. The long-recognized formation of ectopic mesenchymal tissue in the artery wall was a clue that MSCs are present in the adult artery wall. These stem cells, which were first identified in the marrow stroma, can differentiate along multiple lineages and give rise to cartilage, bone, fat, muscle, and vascular tissue in vitro and in vivo. Similar cells with multilineage and self-renewal capacity have also been harvested and cultured from muscle, blood, fat, and now adult vascular tissue. PBMCs also may serve as progenitors for endothelium and possibly smooth muscle. Marrow cells appear to enter the circulation and engraft vascular and other connective tissues, especially at sites of injury and in tissue transplant grafts. Conversely, provocative evidence suggests that cells from vascular tissue may enter the circulation and engraft remote organs. Yet, the possibility remains that MSCs from the bone marrow or the artery wall may permit human tissue regeneration and repair, an exciting future prospect for cardiovascular disease. … [find out more >>]
June 12, 2007 Fetal Cells and their Contribution to Cellular Therapy
In this study scientists have shown the fetal liver cell engraftments into multiple tissues of adult healthy mice, achieved without suppressing the animals' immune systems … [find out more >>]
October 31, 2006 Opposite Phenotypes of Cancer and Aging
A comparison between malignant and aging cells shows that cancer cells do not age, can proliferate without limits, show increased metabolism. As a result, cancer cells supplant senescent cells. Thus, cancer manifests itself as local uncontrolled "rejuvenation" in an organism. … [find out more >>]
May 25, 2006 Bone Marrow Transplants to Recover Brain
Impairments in motor coordination and cognition in normal and pathological aging are often accompanied by structural changes, that is, loss of synapses and neurons. Also, it has been shown recently that bone marrow stem cells can give origin to cells of different tissues, including neural cells. Given the therapeutic implications of increasing health and functional possibilities in the aged brain, scientists have tested the effects of rat femur bone marrow stem cells (rBMSCs) grafting to the striatum hippocampus of aged rats with motor or cognitive deficits, respectively … [find out more >>]
May 12, 2006 Problems Associated with Cloning Adult Animals Using Somatic Cell Nuclear Transfer
In 1997, Wilmut et al. announced the birth of Dolly, the first ever clone of an adult animal. To date, adult sheep, goats, cattle, mice, pigs, cats and rabbits have been cloned using somatic cell nuclear transfer. The ultimate challenge of cloning procedures is to reprogram the somatic cell nucleus for development of the early embryo. The cell type of choice for reprogramming the somatic nucleus is an enucleated oocyte. Given that somatic cells are easily obtained from adult animals, cultured in the laboratory and then genetically modified, cloning procedures are ideal for introducing specific genetic modifications in farm animals … [find out more >>]
April 10, 2006 Therapeutic Approaches for Cellular and Tissue Therapy
Tissue engineering can be defined as the use of biomaterials with or without small molecules, cells, genes, or gene products to maintain, replace, or repair organ function with the objective of correcting the underlying pathology. This new field of medicine is based on the use of engineered cells, tissues, and synthetic materials that can potentially extend and improve a patient�s life. At the present time, treatments for organ or tissue loss include organ transplants, surgical reconstruction, the use of mechanical devices, and, recently, cellular therapy. The research and development of tissues and cell-based products have taken many approaches to advance the field of regenerative medicine … [find out more >>]
April 7, 2006 Regenerative Medicine: A Future in Stem Cells by David M. Brown (presentation)
Lots of controversial data is obtained on embryonic stem cells. Different authors display very variable results. What just disables to make final conclusions on embryonic cells and their application; beside its great regenerative potential they carry majority of dangers. Taking aside ethical issues scientists should completely learn how to manipulate these tiny nuclear power �stations� by not driving them to a-bombs instead. The presentation clearly shows the abilities and opportunities of stem cells, what has been done up to the year 2004 … [find out more >>]
March 15, 2006 Effect of Aging on the Pluripotential Capacity of Human CD105(+) Mesenchymal Stem Cells
Cells were obtained from young (n=10, 24±6.4 years) and elderly (n=9, 77±8.4 years) donors. Cell senescence was assessed by telomere length assays and lipofuscin accumulation. Cell pluripotentiality was analysed by adipogenic and osteogenic induction media, and myocyte phenotype was attempted with 5-azacytidine (5-AZ). Immunofluorescence, Western blot, transmission electron microscopy and fluo-4 confocal imaging were used to analyse the sarcomere, gap junctions and Ca(2+) dynamics … [find out more >>]
March 7, 2006 Telomeres as Replicative and Chronological Clocks
The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. To reinvestigate this question, scientists assayed the skin of aging baboons for telomere dysfunction, a recently discovered biomarker of cellular senescence. Like humans, baboons have a relatively long life span and show age-dependent telomere shortening … [find out more >>]
November 24, 2005 Nuclear transfer and the effect of the number of passages of fetal and adult fibroblasts to nuclear remodeling
Many factors influence the production of cloned animals when using the technique of nuclear transfer. One is the remodeling of the donor cell nucleus within the cytoplasm of the recipient oocyte to organize the first embryonic division. Usually, greater extents of donor cell nuclear remodeling and embryonic development can be achieved when transferring embryonic rather than somatic cell nuclei into the cytoplasm of metaphase II oocytes, although this general rule does not hold true for all species. The number of donor cell passages is another significant factor in cloning by nuclear transfer. Most reports of successful cloning in domestic animal species have used cells of limited passage (3-9) as sources of donor nuclei … [find out more >>]
November 24, 2005 Human Progenitor Liver Epithelial Cells from Fetal Tissue and their Unique Properties
The self-renewal capacity of the liver is well established in models of hepatic resection, injury and carcinogenesis. Although proliferation of mature hepatocytes alone restores the liver after partial hepatectomy and hepatocytes can repopulate the liver repeatedly, under appropriate situations poorly differentiated 'oval cells' arise in the liver and can generate hepatic lineages. Although stem/progenitor cells from adult organs, for example, the pancreas and bone marrow, may also generate mature hepatocytes, such cells are rare in the adult liver. The engraftment of transplanted cells in the liver drew significant interest from the field of cell therapy … [find out more >>]
October 24, 2005 Therapeutic Cloning – Remarks
Cloning of mammals by nuclear transfer was introduced in 1986 and gained attention by the report of the birth of Dolly the sheep in 1997. To date, seven mammalian species have been cloned from adult cells, with the notable exception of primates. Mouse cloning has been possible since 1998. The versatility of this small mammal has propelled the mouse as the experimental model of choice for developing new cloning strategies and applications. Therapeutic cloning, in its current embodiment, entails the derivation of embryonic stem (ES) cell lines from an already born organism. This individual may suffer from a disease that is potentially responsive to autologous cell replacement … [find out more >>]
October 19, 2005 Progenitor Cells from Fetal Liver
The liver can regenerate itself through the progenitor cells it harbors. It was demonstrated the isolation of epithelial progenitor/stem cells from the fetal human liver, which contains a large number of hepatoblasts with very wide spectra of features and capabilities. Progenitor liver cells displayed clonogenic capacity, expressed genes observed in hepatocytes, bile duct cells and oval cells, and incorporated genes transferred by adenoviral or lentiviral vectors. Under culture conditions, progenitor cells proliferated for several months, with each cell undergoing more than forty divisions, but they retained normal karyotypes … [find out more >>]
July 8, 2005 Fetal Stem Cells Compared to Adult Stem Cells – the Advantages
Fetal stem cells are nothing new. Umbilical cord blood haemopoietic stem cells (HSC) have been extensively investigated and widely utilized over the last 10 to 20 years and fetal neural tissue has already been used therapeutically in Parkinson's disease, with some evidence of clinical improvement. Recent interest in stem cell biology and its therapeutic potential has led to the search for fetal stem cells in fetal organs obtained at termination of pregnancy, as well as for accessible sources of fetal stem cells that might be collected for autologous use in ongoing pregnancies. Stem cells obtained from fetal blood and tissues are believed to have similar properties and immunophenotype to comparable adult tissue-derived stem cells, although their development potential is more restricted than pluripotent embryonic stem (ES) cells … [find out more >>]
June 7, 2005 Stem Cell Ageing
The quantitative and qualitative effects of ageing on stem cells are not well understood, although it is believed that stem cells from a younger individual should have greater potential. Thus, many investigators suggest that fetal stem cells should have an advantage over adult stem cells in cell replacement therapies. … [find out more >>]
March 17, 2005 Regeneration of Pancreas
In vertebrates, the process of gastrulation takes place very early during the development of the embryo. This process reorganizes the embryo's cells into 3 layers: ectoderm, endoderm, and mesoderm. The ectoderm forms the skin and the central nervous system; the mesoderm gives rise to the cells from which blood, bone, and muscle are derived; and the endoderm forms the respiratory and digestive tracts. The embryonic endoderm, taking the shape of the primitive gut tube, serves as a template for the gastrointestinal tract from which the embryonic pancreas eventually buds. It has been shown that the branching morphogenesis of the pancreatic bud gives rise to the ducts and the acinar components of the gland … [find out more >>]
December 15, 2004 Stem Cells
Few subjects in biomedical science have captured the imagination of both the scientific community and the public, as has the use of stem cells for the repair of damaged tissues. Because they may be able to replace cells that have atrophied or have been lost entirely, stem cells offer the hope of restoration of cellular function and relief from suffering associated with many disabling disorders. Beyond tissue repair, cultured stem cells might also find application in the analyses of disease mechanisms and normal development, as assays for screening new drugs, and as vehicles for gene therapy … [find out more >>]
August 9, 2004 Embryonic Stem Cells from Primates
Embryonic stem (ES) cells were first derived from the inner cell mass (ICM) of inbred mouse embryos in 1981 by Martin, Evans and Kaufman. Recently, ES cells were successfully derived from non-human primate and human embryos. The National Institutes of Health listed 64 human ES cell lines available for research in 2001; however, only a few had been characterized and studied. Similarly, less than 7 of the more than 20 monkey ES cell lines have been well characterized apart from establishing pluripotency and genetic stability. Even in the mouse, most ES cell studies have been performed with a single inbred mouse cell line. The extent of diversity among primate ES cell lines is currently unknown … [find out more >>]
July 22, 2004 Fetal Hematopoietic Stem Cell Circulation and Homing During Development
During fetal development, the primary anatomical concentration of hematopoietic stem cells (HSCs) changes location several times. The migration of blood-borne progenitors is essential for the establishment of hematopoiesis in subsequent hematopoietic tissues. The speculation that this fetal migration process occurs as a series of distinct, timed developmental events, wherein large numbers of fetal HSCs simultaneously enter the bloodstream to seed newly forming hematopoietic organs, arose from observations that a decrease in HSCs and/or hematopoietic progenitor numbers in primary hematopoietic tissues occurs just prior to the seeding of newly forming hematopoietic sites ... [find out more >>]
June 3, 2004 Skin, Stem Cells and Skin Regeneration
The skin is the first line of defense to protect the body from dehydration, injury, and infection. To meet these needs, the skin has evolved an elaborate differentiation process that results in a tough, water-impermeable outer covering that is constantly renewable. Mammalian skin consists of both dermal and epidermal components; this discussion will be restricted to the epidermal cells, referred to as keratinocytes. The mammalian epidermis is a stratified tissue, anchored to a basement membrane ... [find out more >>]
May 21, 2004 New Approach to Treat Heart Failure
Research into myocardial regeneration has an exciting future, shown by the results of experimental and clinical work challenging the dogma that the heart is a post mitotic non-regenerating organ. Such studies have initiated a lively debate about the feasibility of novel treatment approaches leading to the recovery of damaged myocardial tissue. The possibility of reconstituting dead myocardium by endogenous cardiomyocyte replication, transplantation, or activation of stem cells-or even cloning of an artificial heart-is being advanced, and will be a major subject of future research. Although health expenditure for heart failure in the industrial world is high, we are still a long way from being able to treat the cause of reduced myocardial contractility ... [find out more >>]
May 6, 2004 Nuclear Reprogramming
Nuclear reprogramming is a term used to describe changes in gene activities that are induced experimentally by introducing nuclei into a new cytoplasmic environment. When nuclei from partially or fully differentiated cells are transplanted to enucleated eggs of Amphibia or mammals in second meiotic metaphase, blastula or blastocyst embryos can be obtained, and these can form a wide range of tissues and cell types. The multipotency of these nuclear transplant embryos means that they share some characteristics of early stem cells. Indeed those nuclear transplant embryos that undergo growth (after feeding in Amphibia, and after implantation in mammals) to become adults must contain stem cells for renewing tissues ... [find out more >>]
April 13, 2004 Regulation of Adult Neurogenesis
Presumably, the 'hard-wired' neuronal circuitry of the adult brain dissuades addition of new neurons, which could potentially disrupt existing circuits. This is borne out by the fact that, in general, new neurons are not produced in the mature brain. However, recent studies have established that the adult brain does maintain discrete regions of neurogenesis from which new neurons migrate and become incorporated into the functional circuitry of the brain. These neurogenic zones appear to be vestiges of the original developmental program that initiates brain formation. The largest of these germinal regions in the adult brain is the subventricular zone (SVZ), which lines the lateral walls of the lateral ventricles ... [find out more >>]
March 24, 2004 Neuronal Regeneration After Complete Transection
The complete transection of the adult mammalian spinal cord is believed to lead to irreparable, permanent loss of connectivity. The execution of coordinated movements depends on control exerted by higher centers in the brain. After transection in the rat spinal cord, the neurons responsible for contraction of muscles of the hindlimb, which are located in the lumbar enlargements of the cord, are left intact but are not functional because of lack of connections from the supraspinal control pathways. One necessary element of recovery in post-traumatic spinal cord is long tract axonal regeneration. Pathological changes after spinal cord injury (including scar formation, myelin inhibition, neuronal apoptosis, or necrosis) limit axonal regeneration after the injury ... [find out more >>]
March 9, 2004 Single Gene Bmi1 Involved in Stem Cell Senescence
Many tissues are maintained throughout the lifespan of an organism by a small number of adult stem cells. These cells are unique in that they have both the ability to give rise to new stem cells via a process called self-renewal and the ability to differentiate into the mature cells of a tissue. To maintain tissue homeostasis, stem cells have developed strict regulatory mechanisms to self-renew, differentiate, and prevent premature senescence and apoptosis. The recent observation that Bmi1, a Polycomb group repressor, is essential for the self-renewal of adult murine hematopoietic stem cells (HSCs) and neuronal stem cells, in part via repression of genes involved in senescence, suggests that stem cells have evolved specific mechanisms to repress senescence and to prolong their capacity to proliferate ... [find out more >>]
February 25, 2004 Aging in Cloned Animals
Dolly the sheep, the first cloned mammal in the world, was put down on February 14th of 2003. She was suffering from a virus that caused a tumor in the lung. This has triggered a new round of debate on cloning, particularly on the aging problems of cloned animals. Scientists have long worried that cloned animals might inherit its age from its cell donor, thus being born old and die early. Here we focus on telomeres – the units which are at the end of all chromosomes and discuss how telomeres are related to the ageing problems of clones ... [find out more >>]
January 13, 2004 Adult Stem Cells
Adult human stem cells that are intrinsic to various tissues have been described and characterized, some of them only recently. These cells are capable of maintaining, generating, and replacing terminally differentiated cells within their own specific tissue as a consequence of physiologic cell turnover or tissue damage due to injury. Hematopoietic stem cells that give rise to blood cells and move between bone marrow and peripheral blood are the best-characterized adult stem cells in humans. Recent data suggest that adult stem cells generate differentiated cells beyond their own tissue boundaries ... [find out more >>]
December 24, 2003 Stem Cells Already in Use for Tissue Engineering
What do the stem cells, aging and tissue engineering have in common? Stem cells are the main functionaries of all organs and tissues it means they are responsible for renovation. Aging is evolutionary gained process responsible for elimination of older and not highly adapted organisms from population; introduction of new, more advanced genotypes into the population. Tissue engineering- 10 years old scientific field where stem cells are used to engineer living tissue and organs, which could be transplanted/introduced into aged organisms to make them feel better and rejuvenate. What is exactly made in this promising area for this time? Does this help us to prolong our living and change the way of living driving us to theoretical immortality? ... [find out more >>]
December 14, 2003 The Chiaroscuro Stem Cell
Owen first recognized stem cells experimentally in 1945, when he found lifelong blood chimerism between twin cows. He postulated that an interchange of cells between bovine twin embryos occurred as a result of conjoined blood vessels and that the interchanging cell had to be "ancestral" to the terminal erythrocyte. More than 15 years later, investigators formally tested for these ancestral blood cells by preventing radiation death in mice with bone marrow transplantation. These stem cells were noted for their ability to give rise to clonal colonies of differentiated blood cells in the recipient spleen and for their ability to rescue subsequent generations of lethally irradiated mice. This multilineage reconstitution by a self-renewing cell is a cardinal feature of stem cells. To this day, transplantation experiments like those performed in the 1960s that showed clonal, robust, and functional differentiation by a cell transplantable over many generations remain the gold standard in testing stem cells ... [find out more >>]
December 8, 2003 Stem Cells' Turnover in Aging
Aging is a continuous process beginning at the union of the sperm and the egg. The zygote, of course, is the ultimate stem cell with unlimited developmental potency or plasticity. Development in complex multicellular organisms is all about the compartmentalization and specialization of physiological functions into organ systems. With it goes compartmentalization of stem cells that to various degrees retain some multipotency. A number of factors may conspire to alter the overall multipotency of the stem cell population during aging. For example, as a result of damage acquired through replication or toxic metabolic products, a stem cell's repertoire of developmental programs may be restricted ... [find out more >>]
December 3, 2003 Aging is Linked to Stem Cell Ware Out
Aging has a variety of definitions and implications depending on one's perspective. From an actuarial viewpoint, it may be defined as an increasing probability of death with the passage of time. There are two major theories of organism's aging: evolutionary and damage-based. The former posits that natural selection favors a genetic composition that enhances reproductive fitness and fecundity. According to the theory, since the effect of this genetic repertoire on vitality following the reproductive lifespan is immaterial to the species, genes have been selected and accumulated which favor reproductive success but have negative effects in later life, thus limiting lifespan ... [find out more >>]
November 20, 2003 Neurogenesis, Already the Reality
As observed by the pioneering neuroscientist Santiago Ramon Cajal, the mature CNS was distinguished from the developing nervous system by the lack of growth and cellular regeneration. The fixed neuronal population of the adult brain was understood to be necessary to maintain the functional stability of adult brain circuitry. This explanation has also been offered to account for the lack of endogenous CNS repair following injury or disease ... [find out more >>]
August 12, 2003 Adult Stem Cells – Possible Panacea
Since birth, child caries fixed amount of stem cells of various lineages. Starting from hematopoetic stem cells, going to stem cells persisting in different tissue involved in its regeneration. During ontogenesis number of pluripotent cells is decreasing. When person reaches his 60-70 years, this number of pluripotent cells is near the critical level. Because of that ... [find out more >>]
May 22, 2003 Telomeres Reconstitution in Cloning
The production of viable, fertile cloned animals by nuclear transplantation of somatic cells from cultured cell lines and adult tissues has challenged the understanding of terminal cell differentiation, cellular aging, and the proliferative capacity of cells. Successful cloning requires the reprogramming of the donor nuclei from pluripotent or differentiated cells to an undifferentiated state to permit the temporal and spatial reexpression of genes involved in embryo and fetal development. Somatic nuclei progressively acquire ... [find out more >>]
April 4, 2003 BMT and Neurons
New discoveries in stem cell technology are highly promising to treat lots of diseases of different cause. Eva Merey et al. in their recent study revealed that ... [find out more >>]
February 28, 2003 Cloned Mice Encounter Early Aging Process
The group of scientists working with mouse cloning has reported that cloned mice in comparison with normal are sensitive to aging process. They have cloned 12 male mice from ... [find out more >>]
January 22, 2003 Perspectives to Treat Neuronal Degeneration Diseases Using Stem Cell Technology
Snyder et al.* have made a very promising finding concerned with embryonic stem cell therapy in treating injured brain. They have found that ... [find out more >>]
January 2, 2003 Future Medicine Nowadays
New approaches to the cancer treatment are on the way. All previous methods for treating cancer in near future could be supplemented with new one. In nowadays ... [find out more >>]
October 15, 2002 Stem Cells Rescue Retina, New Perspective
Bone marrow stem cells might one day deliver drugs to the eye, halting age- and diabetes-related blindness. The cells can ... [find out more >>]
September 13, 2002 Could find some perspective?
Severe combined immunodeficiencies (SCID) are rare disorders that represent paediatric medical emergencies, as the ... [find out more >>]
August 22, 2002 Nuclear Transfer in Humans - the Perspective
Human therapeutic cloning requires the reprogramming of a somatic cell by nuclear transfer to generate autologous totipotent stem cells. Emerging ... [find out more >>]
August 12, 2002 Cloning in Disease Treatment
The successful application of nuclear transfer techniques to a range of mammalian species has brought ... [find out more >>]
August 8, 2002 Parkinson's Disease and Cell Transplantation
Parkinson's disease symptoms can be improved by transplanting fetal dopamine cells into the ... [find out more >>]
August 4, 2002 Perspectives for ES Cells
Robl et al. have developed a method, using nuclear transplantation, to produce transgenic embryonic stem (ES)-like cells from ... [find out more >>]