Nature Insight Stem Cells - Blog Posts with Comments

Stem-cell therapies for blood diseases - FREE ACCESS

afrood — 2006-06-28T18:28:47+00:00

Claudio Bordignon

For decades, transplantation of haematopoietic stem cells — either unmodified, or genetically modified to correct genetic disorders — has been used to treat disorders of the blood and immune systems. The present challenge is to reduce the risk of such transplants and increase the number of patients who can safely access this treatment. In developing countries, such 'one-shot' treatments are highly desirable because chronic treatments are difficult to sustain. To make these therapies more accessible and effective it will be important to improve clinical protocols and gene-delivery vectors, and to gain a deeper understanding of stem cells.

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Comment 1 (Stem-cell therapies for blood diseases - FREE ACCESS)

Dick Pelletier — 2006-07-19T01:02:13+00:00

• In a unique discovery, scientists have demonstrated that undifferentiated human stem cells can travel down a developmental pathway and become blood cells.
Researchers Walter E. Goldstein and Warren K. Miller have developed a special procedure that actually turns stem cells into red blood cells.

“For the first time in history, doctors will be able to obtain and transfuse disease-free bioreactor-produced universal blood properly matched to patient needs”, Goldstein said. Moreover, the ability to create blood in the lab has obvious implications for augmenting human blood supplies around the world to treat cancers of the blood and bone marrow (such as leukemia and myeloma).

Goldstein, Coordinator of the Biotechnology Center at UNLV, co-developed the technology prior to coming to UNLV; but he hopes to bring their discovery into the UNLV Biotech Center for development to commercialization.
The researchers emphasize that while the work shows great promise towards taming stem cells, it faces many challenges and remains basic science. Its use in transplants and transfusions may be years away. However, navigating the clinical trial world and gaining FDA approval could happen as early as 2015.

Potential of stem-cell-based therapies for heart disease - FREE ACCESS

afrood — 2006-06-28T18:26:55+00:00

Deepak Srivastava and Kathryn N. Ivey

The use of stem cells to generate replacement cells for damaged heart muscle, valves, vessels and conduction cells holds great potential. Recent identification of multipotent progenitor cells in the heart and improved understanding of developmental processes relevant to pluripotent embryonic stem cells may facilitate the generation of specific types of cell that can be used to treat human heart disease. Secreted factors from circulating progenitor cells that localize to sites of damage may also be useful for tissue protection or neovascularization. The exciting discoveries in basic science will require rigorous testing in animal models to determine those most worthy of future clinical trials.

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Comment 1 (Potential of stem-cell-based therapies for heart disease - FREE ACCESS)

Robert Jacklin — 2006-06-29T22:28:01+00:00

>>improved understanding of developmental processes relevant to pluripotent embryonic stem cells may facilitate the generation of specific types of cell that can be used to treat human heart disease.

The statement "may facilitate the generation of specific types of cell that can be used to treat human heart disease." is already out of date according to Geron Corporation. They have shown slides at research meetings for the last couple of years of functioning Cardiomyocytes they derived from HESC's.
These same cells have been shown to improve function in vivo.

http://www.geron.com/pressview.asp?id=727

Comment 2 (Potential of stem-cell-based therapies for heart disease - FREE ACCESS)

Deepak Srivastava — 2006-07-06T17:20:47+00:00

We appreciate the comment on previous efforts to guide embryonic stem cells into the cardiomyocyte lineage. It is true that we and many other investigators are able to encourage cardiomyocyte differentiation in ES cells, however the process is very inefficient and time-consuming. Despite that, ES cells have been differentiated and introduced into rodent hearts and were able to integrate as mentioned. However, this has not yet been done in humans and it would be misleading and premature to state that specific ES cell derived cells are currently being used to treat human disease. While there is great promise that human disease will be treated with ES-derived cells, it is critical that scientific advances be portrayed in a realistic light without unnecessary “hype” and generation of unrealistic expectations.

Stem cells for the treatment of neurological disorders - FREE ACCESS

afrood — 2006-06-28T18:25:25+00:00

Olle Lindvall and Zaal Kokaia

Many common neurological disorders, such as Parkinson's disease, stroke and multiple sclerosis, are caused by a loss of neurons and glial cells. In recent years, neurons and glia have been generated successfully from stem cells in culture, fuelling efforts to develop stem-cell-based transplantation therapies for human patients. More recently, efforts have been extended to stimulating the formation and preventing the death of neurons and glial cells produced by endogenous stem cells within the adult central nervous system. The next step is to translate these exciting advances from the laboratory into clinically useful therapies.

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Generation of neuronal variability and complexity - FREE ACCESS

afrood — 2006-06-28T18:23:42+00:00

Alysson R. Muotri and Fred H. Gage

The production of specialized differentiated neurons derived from stem cells has been proposed as a revolutionary technology for regenerative medicine. However, few examples of specific neuronal cell differentiation have been described so far. Although stem-cell tissue replacement might be seemingly straightforward in other cases, the high degree of complexity of the nervous system raises the challenge of tissue replacement substantially. Understanding mechanisms of neuronal diversification will not only be relevant for therapeutic purposes but might also shed light on the differences in cognitive abilities, personality traits and psychiatric conditions observed in humans.

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Stem cells, ageing and the quest for immortality - FREE ACCESS

afrood — 2006-06-28T18:21:29+00:00

Thomas A. Rando

Adult stem cells reside in most mammalian tissues, but the extent to which they contribute to normal homeostasis and repair varies widely. There is an overall decline in tissue regenerative potential with age, and the question arises as to whether this is due to the intrinsic ageing of stem cells or, rather, to the impairment of stem-cell function in the aged tissue environment. Unravelling these distinct contributions to the aged phenotype will be critical to the success of any therapeutic application of stem cells in the emerging field of regenerative medicine with respect to tissue injury, degenerative diseases or normal functional declines that accompany ageing.

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Comment 1 (Stem cells, ageing and the quest for immortality - FREE ACCESS)

Attila Csordas — 2007-01-15T10:07:50+00:00

This is definitely the best and most thoughtful paper on the topic yet. http://pimm.wordpress.com/2007/01/12/best-paper-on-stem-cells-and-ageing-by-thomas-rando-figure-1/

Comment 2 (Stem cells, ageing and the quest for immortality - FREE ACCESS)

Shi V. Liu — 2007-09-29T17:03:41+00:00

Earlier and butter publications on asymmetric cell reproduction and intrinsic aging

Rando’s quest for immortality [1] is a repetition of medieval fiction and thus a reversal of scientific progress [2]. His recent publication on nonrandom DNA segregation [3] just confirmed some previous discoveries [4-6] but still contains many fundamental mistakes [7-8]. Unfortunately, “top” journals have given Rando too much space in publishing his erroneous views [9]. On the contrary so far they have suppressed alternative but very correct views from a true research pioneer studying cell life [10].
I concluded years ago that cell reproduction (often incorrectly characterized as cell division) is asymmetric regardless of the morphological similarity between two cells formed from one cell [4]. My unique view is that two cells formed from one cell bear a mother-daughter rather than a twin-daughter relationship. Furthermore, I was the first in proposing that a mother cell retains the old template DNA strand and segregates the young template DNA strand to its daughter cell(s) [4]. A precise depiction of this normal DNA segregation pattern during the life span of a cell was published which links DNA aging with cell aging and combines genetics with epigenetics [5].
That DNA-cell aging synchrony was used as an example for the existence of a molecule-cell-organism aging axis throughout the development of multicellular organisms from single zygote cells [6]. This theoretical framework not only provides a deep insight into the fundamental mechanisms of biotic aging [11] but also clarifies several paradoxes in stem cell research and, moreover, uncovers a conceptual limitation of the ‘Hayflick limit’ [12].
My new cell life theory [4-6] provides a linkage between semi-conservative DNA replication and generation-asymmetric cell reproduction. This understanding provides a basis for arguing against the popular but flawed ‘immortal strand’ hypothesis. It also reveals the self-contradictory nature of the ‘self-renewal’ claim for stem cells [13]. The intrinsic aging process that, as I assume, occurs in all cells disproves any immortality claim for any cell [14]. Thus, this new cell life theory will probably be pivotal in revolutionizing cell-based biology by virtue of its superior understanding of the relationship between aging and diseases such as cancer compared to some currently prevailing opinions and its insights into various enigmas still puzzling stem cell researchers and cloning experts [15-19].
Rando and others not only promoted some wrong views on cell life but also committed severe misconduct by distorting the history on cell life research and rubber credit that should be deserved for a true pioneer [20-24].

References

[1] Rando TA. Stem cells, ageing and the quest for immortality. Nature 2006; 441: 1080-1086.
[2] Liu SV. Put the immortality concept to death. Logical Biology. 2006; 6: 52-53.
[3] Conboy MJ, Karasov AO, Rando TA. High incidence of non-random template strand segregation and asymmetric fate determination in dividing stem cells and their progeny. 2007; PLoS Biol 5:e102.
[4] Liu SV. Tracking bacterial growth in liquid media and a new bacterial life model. Science in China (Series C: Life Science) 1999; 42: 644-654 (English) and 29: 571-579 (Chinese).
[5] Liu SV. Linking DNA aging with cell aging and combining genetics with epigenetics. Logical Biology 2005; 5: 51-55.
[6] Liu SV. A theoretical framework for understanding biotic aging from molecule to organism in multicellular life. Logical Biology 2005; 5: 109-116.
[7] Liu SV. Revisit semi-conservative DNA replication and immortal DNA strand hypothesis. Logical Biology 2006; 6: 54-61.
[8] Liu SV. I am the mother, you stupid! Logical Biology 2007; 7: 29-33.
[9] Rando TA. The immortal strand hypothesis: segregation and reconstruction. Cell. 2007; 129, 1239-1243.
[10] Liu SV. Immortal strand does not exist but nonrandom strand segregation should be universal. Logical Biology 2007; 7: 50-60.
[11] Liu SV. Searching for the deep root and fundamental mechanism of biotic aging. Logical Biology 2005; 5: 89-91.
[12] Liu SV. Understanding the limit of the Hayflick Limit. Logical Biology 2005; 5:58-65.
[13] Liu SV. Stem cells’ self-renewal or cell biologists’ self-cheating? Logical Biology 2006; 6:106-109.
[14] Liu SV. Are stem cells really immortal cells? Logical Biology 2006; 6:71-75.
[15] Liu SV. What is a stem cell? Logical Biology 2007; 7:12-17.
[16] Liu SV. Cell division deception and stem cell confusion. Pioneer 2007; 2:7-10.
[17] Liu SV. Increased cloning efficiency over differentiation hierarchy: True paradigm shift or false outlier presentation? Logical Biology 2006; 6:110-112.
[18] Liu SV. iPS cells: Stem cells induced from terminally differentiated cells or just pre-existing stem cells being detected? Logical Biology 2007; 7:63-65.
[19] Liu SV. Are iPS cells really indistinguishable from ES cells? Logical Biology 2007; 7:66-68.
[20] Liu SV. A public robbery of science in the public library of science. Logical Biology 2005; 5:76-78.
[21] Liu SV. I cannot believe this, you shameful! - A revelation of a severe publishing misconduct. Scientific Ethics 2007; 2:48-50.
[22] Liu SV. Another reinvention of the wheel and an outright credit ribbery. Scientific Ethics 2007; 2:61-74.
[23] Liu SV. This outrageous lie has got to stop! Scientific Ethics 2007; 2:79-85.
[24] Liu SV. The dark side of Amar Klar. Scientific Ethics 2007; 2:96-101.

(Many more publications relevant to this subject can be found in a central communication forum at http://im1.biz)

Shi V. Liu
Eagle Institute of Molecular Medicine
Apex, NC 27502 USA
E-mail address: SVL@logibio.com

The stem-cell niche as an entity of action - FREE ACCESS

afrood — 2006-06-28T18:17:43+00:00

David T. Scadden

Stem-cell populations are established in 'niches' — specific anatomic locations that regulate how they participate in tissue generation, maintenance and repair. The niche saves stem cells from depletion, while protecting the host from over-exuberant stem-cell proliferation. It constitutes a basic unit of tissue physiology, integrating signals that mediate the balanced response of stem cells to the needs of organisms. Yet the niche may also induce pathologies by imposing aberrant function on stem cells or other targets. The interplay between stem cells and their niche creates the dynamic system necessary for sustaining tissues, and for the ultimate design of stem-cell therapeutics.

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Asymmetric and symmetric stem-cell divisions in development and cancer - FREE ACCESS

afrood — 2006-06-28T18:14:17+00:00

Sean J. Morrison and Judith Kimble

Much has been made of the idea that asymmetric cell division is a defining characteristic of stem cells that enables them to simultaneously perpetuate themselves (self-renew) and generate differentiated progeny. Yet many stem cells can divide symmetrically, particularly when they are expanding in number during development or after injury. Thus, asymmetric division is not necessary for stem-cell identity but rather is a tool that stem cells can use to maintain appropriate numbers of progeny. The facultative use of symmetric or asymmetric divisions by stem cells may be a key adaptation that is crucial for adult regenerative capacity.

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A glossary for stem-cell biology - FREE ACCESS

afrood — 2006-06-28T18:13:37+00:00

Austin Smith

Stem-cell biology is in a phase of dynamic expansion and is forming connections with a broad range of basic and applied disciplines. The field is simultaneously exposed to public and political scrutiny. A common language in the stem-cell community is an important tool for coherent exposition to these diverse audiences, not least because certain terms in the stem-cell vocabulary are used differently in other fields.

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Stem-cell Biology editorial - FREE ACCESS

afrood — 2006-06-28T18:04:35+00:00

Natalie DeWitt

More than 30 years ago, neurologist Oliver Sacks wrote of the Parkinson's drug l-dopa: "It is impossible to avoid the feeling that here, over and above all legitimate enthusiasms, there is this special enthusiasm, this mysticism, of a magical sort."

It is striking how aptly these words describe the current enchantment with stem cells. Now, 25 years after scientists first isolated mouse embryonic stem cells, it is possible to isolate and culture stem cells from embryos and adult tissues of many species, including humans.

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Nuclear reprogramming and pluripotency - FREE ACCESS

afrood — 2006-06-28T17:47:36+00:00

Konrad Hochedlinger and Rudolf Jaenisch

The cloning of mammals from differentiated donor cells has refuted the old dogma that development is an irreversible process. It has demonstrated that the oocyte can reprogramme an adult nucleus into an embryonic state that can direct development of a new organism. The prospect of deriving patient-specific embryonic stem cells by nuclear transfer underscores the potential use of this technology in regenerative medicine. The future challenge will be to study alternatives to nuclear transfer in order to recapitulate reprogramming in a Petri dish without the use of oocytes.

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