 |
|
Tissue regeneration operates differently than expected
August 05, 2005Max Planck researchers in Bad Nauheim discover the mechanism by which adult stem cells are integrated into skeletal or heart muscle tissue
There is disagreement, however, about the mechanism on which repair processes are based. Scientists from the Max Planck Institute for Heart and Lung Research in Bad Nauheim, Germany, in co-operation with colleagues from Martin Luther University in Halle-Wittenberg, have now shown that skeletal muscle tissue can fuse with adult stem cells, via a mechanism based on the participation of mediators which are generally involved in immune cell activation. Although being unable to transdifferentiate into completely functional muscle cells, they are integrated into the tissue complex by fusing with differentiated tissue cells. In contrast, in the heart muscle tissue the mechanism seems to be different from this. The scientists in Bad Nauheim conclude from their study that adult stem cells are involved in tissue repair processes in a paracrine way by delivering mediating factors rather than by simply becoming components of the regenerating organ. (Genes & Development, August 2005).
Stem cells are fully unspecialised cells which can develop into all kinds of cell types. Embryonic stem cells provide the origin of a developing organ, during the growth of an embryo. For example, mesenchymal cells - stem cells from embryonic connective tissue - transform themselves during embryogenesis into muscle cells, under the influence of certain growth factors.
Other stem cells - adult stem cells - play an important role throughout an organism's life. For example, bone marrow stem cells provide for the replenishment of short-lived blood cells. Adult stem cells can be found locally in various tissues and organs, and we have presumed that they are participating in the repair and maintenance of organ functions.
The controversial idea is that adult stem cells have the potential for transdifferentiation; in other words, that they are able to transmutate from one type of organ cell to another. If that is the case, bone marrow cells would be able to change into lots of different kinds of tissue cells - for example, skeletal muscle cells.
Scientists led by Thomas Braun, Director of the Max Planck Institute for Heart and Lung Research, have discovered by a number of different experimental approaches that mesenchymal stem cells only show a rudimentarily developed potential for transdifferentiation processes. All cases in which functional skeletal muscle cells arose from mesenchymal stem cells were based on the fusion of stem cells with already differentiated muscle cells.
Although, like the researchers from Bad Nauheim show, cultivated mesenchymal stem cells are able to express a number of heart- and skeletal muscle specific genes and undergo some morphologic changes, after they are co-cultured with growth-factor producing feeder cells, finally they did not become entirely functional muscle cells.
Fully-functional muscle cells only developed after the mesenchymal stem cells were cultivated together with skeletal or heart muscle cells. This was indicated by the green fluorescence of muscle cells derived from the fusion with a stem cell which before had been labelled with the green dye. In contrast, no green fluorescing muscle cells became evident when stem and muscle cells were spatially separated by a membrane between both cell types. The researchers conclude that this experiments proofs that cell fusion of mesenchymal stem cells and muscle cell but not their transdifferentiation forms the basis for the regeneration mechanism. Additional experiments were focussing on the molecular mechanism underlying the cell fusion process. In these investigations, so-called "chimeric" mouse embryos were produced from mesenchymal stem cells and several mouse mutants: Obviously, the stem cells are recruiting the IL-4/NFAT signalling pathway which also is involved in the activation of T-lymphocytes during immune response.
From the findings presented by Thomas Braun and his collaborators some important consequences for the use of adult stem cells in possible therapeutic approaches could arise, since they contradict the predominant opinion that bone marrow-derived or local stem cells are involved in the regeneration of heart and skeletal musculature by transdifferentiating into muscle cells. By fusing with the cells of the regenerating tissue these cells rather seem to only simulate such a transdifferentiation mechanism. This has major implications for the prospects of stem cell therapies targeting on the regeneration of skeletal or heart musculature.
Max-Planck-Gesellschaft
Other stem cells - adult stem cells - play an important role throughout an organism's life. For example, bone marrow stem cells provide for the replenishment of short-lived blood cells. Adult stem cells can be found locally in various tissues and organs, and we have presumed that they are participating in the repair and maintenance of organ functions.
The controversial idea is that adult stem cells have the potential for transdifferentiation; in other words, that they are able to transmutate from one type of organ cell to another. If that is the case, bone marrow cells would be able to change into lots of different kinds of tissue cells - for example, skeletal muscle cells.
Scientists led by Thomas Braun, Director of the Max Planck Institute for Heart and Lung Research, have discovered by a number of different experimental approaches that mesenchymal stem cells only show a rudimentarily developed potential for transdifferentiation processes. All cases in which functional skeletal muscle cells arose from mesenchymal stem cells were based on the fusion of stem cells with already differentiated muscle cells.
Although, like the researchers from Bad Nauheim show, cultivated mesenchymal stem cells are able to express a number of heart- and skeletal muscle specific genes and undergo some morphologic changes, after they are co-cultured with growth-factor producing feeder cells, finally they did not become entirely functional muscle cells.
Fully-functional muscle cells only developed after the mesenchymal stem cells were cultivated together with skeletal or heart muscle cells. This was indicated by the green fluorescence of muscle cells derived from the fusion with a stem cell which before had been labelled with the green dye. In contrast, no green fluorescing muscle cells became evident when stem and muscle cells were spatially separated by a membrane between both cell types. The researchers conclude that this experiments proofs that cell fusion of mesenchymal stem cells and muscle cell but not their transdifferentiation forms the basis for the regeneration mechanism. Additional experiments were focussing on the molecular mechanism underlying the cell fusion process. In these investigations, so-called "chimeric" mouse embryos were produced from mesenchymal stem cells and several mouse mutants: Obviously, the stem cells are recruiting the IL-4/NFAT signalling pathway which also is involved in the activation of T-lymphocytes during immune response.
From the findings presented by Thomas Braun and his collaborators some important consequences for the use of adult stem cells in possible therapeutic approaches could arise, since they contradict the predominant opinion that bone marrow-derived or local stem cells are involved in the regeneration of heart and skeletal musculature by transdifferentiating into muscle cells. By fusing with the cells of the regenerating tissue these cells rather seem to only simulate such a transdifferentiation mechanism. This has major implications for the prospects of stem cell therapies targeting on the regeneration of skeletal or heart musculature.
Max-Planck-Gesellschaft
Tissue Regeneration Current Events and Tissue Regeneration News RSSOctober 15, 2009 Loss of Tumor-Suppressor and DNA-Maintenance Proteins Causes Tissue Demise, Penn Study Finds
A study published in the October issue of Nature Genetics demonstrates that loss of the tumor-suppressor protein p53, coupled with elimination of the DNA-maintenance protein ATR, severely disrupts tissue maintenance in mice. As a result, tissues deteriorate rapidly, which is generally fatal in these animals. In addition, the study provides supportive evidence for the use of inhibitors of ATR in cancer therapy.
Scientists discover clues to what makes human muscle age
A study led by researchers at the University of California, Berkeley, has identified critical biochemical pathways linked to the aging of human muscle. By manipulating these pathways, the researchers were able to turn back the clock on old human muscle, restoring its ability to repair and rebuild itself.
UCF scientists control living cells with light; advances could enhance stem cells' power
University of Central Florida researchers have shown for the first time that light energy can gently guide and change the orientation of living cells within lab cultures.
Reprogramming Human Cells Without Inserting Genes
A research team comprised of faculty at Worcester Polytechnic Institute's (WPI) Life Sciences and Bioengineering Center (LSBC) and investigators at CellThera, a private company also located at the LSBC, has discovered a novel way to turn on stem cell genes in human fibroblasts (skin cells) without the risks associated with inserting extra genes or using viruses.
Stem cell research: From molecular physiology to therapeutic applications
Stem cell research promises remedies to many devastating diseases that are currently incurable, ranging from diabetes and Parkinson's disease to paralysis.
Resolvins have the potential to resolve periodontal inflammation and restore tissue health
Periodontal (gum) disease is a chronic inflammation initiated by bacteria that affect the gums and bone supporting the teeth, and may eventually result in tissue and tooth loss.
Scripps research scientists find cause of cartilage degeneration in osteoarthritis
The scientists describe their work in this week's Early Edition of the Proceedings of the National Academy of Sciences. In the study, the team shows how the loss of the protein HMGB2, found in the surface layer of joint cartilage, leads to the progressive deterioration of the cartilage that is the hallmark of osteoarthritis.
New 'control knobs' for stem cells identified
Natural changes in voltage that occur across the membrane of adult human stem cells are a powerful controlling factor in the process by which these stem cells differentiate, according to research published by Tufts University scientists.
Receptor could halt blinding diseases, stop tumor growth, preserve neurons after trauma
An international team of researchers has discovered what promises to be the on-off switch behind several major diseases.
Emerging model organisms featured in CSH Protocols
Biological research has long relied on a small number of model organisms, species chosen because they are amenable to laboratory research and suitable for the study of a range of biological problems.
More Tissue Regeneration Current Events and Tissue Regeneration News Articles
 |
20 Years of Guided Bone Regeneration in Implant Denistry by Daniel Buser (Author), Daniel Buser (Editor) This completely revised and updated edition of the bestselling book Guided Bone Regeneration in Implant Dentistry brings the reader up-to-date on the developments in GBR over the past 20 years. The first four chapters focus on the basic science of GBR in implant dentistry. These chapters help the reader to understand the biologic and biomaterial background of this well-documented and well-established surgical technique in implant dentistry essential knowledge for the use of barrier membranes in patients. The second half of the book focuses on the clinical applications of GBR. Each chapter presents specific indications and describes the criteria for patient selection, the step-by-step surgical procedure, and aspects of postoperative treatment. These five clinical chapters reflect the... |
 |
Decleor Exfoliating Shower Gel 6.7oz by Decleor Decleor Exfoliating Shower Gel is a fresh and invigorating exfoliant that cleanses, purifies and exfoliates the skin to leave the body feeling wonderfully clean and satin-smooth to the touch. Benefits: A two in one action combining speed and efficiency. Simplifies exfoliation and intensifies cleansing. Promotes tissue regeneration and the absorption of creams. Suitable for the most sensitive of skins. |
 |
Nature's Bloom Noni Fruit Capsules 250mg (120 count) by Nature's Bloom As an exotic fruit found in tropical areas, noni has a wide range of health applications. Noni is often called as the "Queen of Health Plants" due to its power to improve one's overall health. Noni helps boost the immune system by stimulating the production of the body's T-cells, which act to get rid of unhealthy substances within the body. As a result, noni aids in the defense of cancer formation by increasing immune system action to find and eliminate early cancer cells. Studies have shown that a polysaccharide substance from noni's fruit juices help support normal and healthy cellular tissue growth and regeneration. In addition, noni also contains many of the essential amino acids that are used to maintain the body's operations. |
 |
Musculoskeletal Tissue Regeneration: Biological Materials and Methods (Orthopedic Biology and Medicine) by William S. Pietrzak (Author), William S. Pietrzak (Editor) The repair of musculoskeletal tissue is a vital concern of all surgical specialties, orthopedics and related disciplines. Written by recognized experts in their field, Musculoskeletal Tissue Regeneration: Biological Materials and Methods aims to provide both basic and advanced knowledge of the newer methodologies being developed and introduced to the clinical arena. On the cusp of a revolution, musculoskeletal repair is based on new tools that have recently become available or are about to emerge into clinical practice. By their very nature, these tools require an interdisciplinary approach, utilizing teams comprised of surgeons, engineers, and scientists in collaboration between industry and academia. A valuable resource for researchers, developers, and clinicians, Musculoskeletal... |
 |
Tepezcohuite - Neutral Derma Cleaner Soap by DEL INDIO PAPAGO Mimosa tenuiflora (Jurema, Tepezcohuite) is a perennial evergreen tree or shrub native to the northeastern region of Brazil and found as far north as southern Mexico (Oaxaca and coast of Chiapas). Tepezcohuite my protect and stimulate the generation of collagen and "elastina," as well as providing protecting flavonoids and hyaluronic acid, a building block for tissue regeneration. Tepezcohuite is used to treat acne, psoriasis and herpes. Reduces the appearance of pigmentation imbalances, age spots, stretch marks, scars, cellulite and enlarged pores and also is : * An all Natural Skin Rejuvenator. * Removes all makeup, dirt, oils and grime that clog the pores. * Exfoliates the skin to leave it soft and radiant, removing dead cells and dry skin. * Renews fresh skin tone for a more... |
 |
Biological Interactions on Materials Surfaces: Understanding and Controlling Protein, Cell, and Tissue Responses by David A. Puleo (Editor), Rena Bizios (Editor) Success or failure of biomaterials, whether tissue engineered constructs, joint and dental implants, vascular grafts, or heart valves, depends on molecular-level events that determine subsequent responses of cells and tissues. This book presents the latest developments and state-of-the-art knowledge regarding protein, cell, and tissue interactions with both conventional and nanophase materials. Insight into these biomaterial surface interactions will play a critical role in further developments in fields such as tissue engineering, regenerative medicine, and biocompatibility of implanted materials and devices. With chapters written by leaders in their respective fields, this compendium will be the authoritative source of information for scientists, engineers, and medical researchers... |
 |
Tissue and Organ Regeneration in Adults by Ioannis V. Yannas (Author) Massachusetts Institute of Technology, Cambridge. Volume directed toward the different backgrounds of students from the physical and life sciences. Emphasizes the systemic development of the viewpoint that regeneration is an instance of the synthesis of tissues and organs. Features an extensive bibliography and independent data on organ regeneration from journal literature. |
 |
Proceedings of Light-Activated Tissue Regeneration and Therapy Conference (Lecture Notes in Electrical Engineering) by Ronald Waynant (Editor), Darrell B. Tata (Editor) Proceedings of the Light-Activated Tissue Regeneration and Therapy Conference covers issues such as the latest advances in the field and measurements including the determination of the mechanisms of light-activated tissue regeneration and therapy. Light sources, narrow and broadband, as well as the metrology and medical outcomes they produce, are discussed. This book discusses the following topics: Laser therapy; Mechanism; Photodynamic therapy; Cardiovascular; Pain; Neuroscience/Progenitor and Stem cells; Wound healing; Unusual Sources; Electrical Fields, Optical Fields and Other fields; Dentistry; Diabetes. The book is the first to present the mechanism which explains why light is an effective treatment for so many illnesses and diseases. It not only explains this... |
|
Bone Regeneration: Growth Factors, Augmentation Procedures and Tissue Engineering Applications (Human Anatomy and Physiology) by Vincent Legard (Editor), Remi Schluter (Editor) Bone tissue plays a vital role in the human system for its biological and mechanical activities, resulting from its regenerative capacity and permanent remodelling process. Bone damage, either due to pathologies or traumas, is a very common occurrence and represents a major problem in orthopaedics. This book briefly summarises recent literature concerning modification and applications of osteoinductive materials for reconstructive surgery. Several recent developments of biocomposites containing silica nanoparticles or calcium sulphate intended for bone regeneration are also reported. In addition, new therapies are identified for bone regeneration in an injured or diseased state, as well as for bone loss in ageing. Also discussed in this book is normal bone development, mesenchymal stem... | |
|
Keys for Regeneration: Proceedings of the European Conference on Tissue and Post-Traumatic Regeneration, Geneva, September 3-7, 1990 (Monographs in Developmental Biology) by C. H. Taban (Author), B. Boilly (Editor) |
| © 2009 BrightSurf.com |