1. Want to get periods immediately before attending a religious event? Check this out for tips...
    Dismiss Notice
  2. Would you like to join the IL team? See open jobs!
    Dismiss Notice
  3. What can you teach someone online? Tell us here!
    Dismiss Notice
  4. If someone taught you via skype, what would you want to learn? Tell us here!
    Dismiss Notice

Stem Cells Basics

Discussion in 'Health Issues' started by cheer, Mar 9, 2007.

  1. cheer

    cheer Silver IL'ite

    Messages:
    918
    Likes Received:
    38
    Trophy Points:
    63
    Gender:
    Female
    Stem cells have the remarkable potential to develop into many different cell types in the body. Serving as a sort of repair system for the body, they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

    Research on stem cells is advancing knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. This promising area of science is also leading scientists to investigate the possibility of cell-based therapies to treat disease, which is often referred to as regenerative or reparative medicine.
    Stem cells are one of the most fascinating areas of biology today. But like many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.
    The NIH developed this primer to help readers understand the answers to questions such as: What are stem cells? What different types of stem cells are there and where do they come from? What is the potential for new medical treatments using stem cells? What research is needed to make such treatments a reality?

    A. What are stem cells and why are they important?

    Stem cells have two important characteristics that distinguish them from other types of cells. First, they are unspecialized cells that renew themselves for long periods through cell division. The second is that under certain physiologic or experimental conditions, they can be induced to become cells with special functions such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.
    Scientists primarily work with two kinds of stem cells from animals and humans: embryonic stem cells and adult stem cells, which have different functions and characteristics that will be explained in this document. Scientists discovered ways to obtain or derive stem cells from early mouse embryos more than 20 years ago. Many years of detailed study of the biology of mouse stem cells led to the discovery, in 1998, of how to isolate stem cells from human embryos and grow the cells in the laboratory. These are called human embryonic stem cells. The embryos used in these studies were created for infertility purposes through in vitro fertilization procedures and when they were no longer needed for that purpose, they were donated for research with the informed consent of the donor.

    Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, stem cells in developing tissues give rise to the multiple specialized cell types that make up the heart, lung, skin, and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.


    It has been hypothesized by scientists that stem cells may, at some point in the future, become the basis for treating diseases such as Parkinson's disease, diabetes, and heart disease.


    Scientists want to study stem cells in the laboratory so they can learn about their essential properties and what makes them different from specialized cell types. As scientists learn more about stem cells, it may become possible to use the cells not just in cell-based therapies, but also for screening new drugs and toxins and understanding birth defects. However, as mentioned above, human embryonic stem cells have only been studied since 1998. Therefore, in order to develop such treatments scientists are intensively studying the fundamental properties of stem cells, which include:
    1. determining precisely how stem cells remain unspecialized and self renewing for many years; and
    2. identifying the signals that cause stem cells to become specialized cells.
     
    Loading...

  2. cheer

    cheer Silver IL'ite

    Messages:
    918
    Likes Received:
    38
    Trophy Points:
    63
    Gender:
    Female
    What are the potential uses of human stem cells and the obstacles that must be overcome before these potential uses will be realized?

    There are many ways in which human stem cells can be used in basic research and in clinical research. However, there are many technical hurdles between the promise of stem cells and the realization of these uses, which will only be overcome by continued intensive stem cell research.

    Studies of human embryonic stem cells may yield information about the complex events that occur during human development. A primary goal of this work is to identify how undifferentiated stem cells become differentiated. Scientists know that turning genes on and off is central to this process. Some of the most serious medical conditions, such as cancer and birth defects, are due to abnormal cell division and differentiation. A better understanding of the genetic and molecular controls of these processes may yield information about how such diseases arise and suggest new strategies for therapy. A significant hurdle to this use and most uses of stem cells is that scientists do not yet fully understand the signals that turn specific genes on and off to influence the differentiation of the stem cell.

    Human stem cells could also be used to test new drugs. For example, new medications could be tested for safety on differentiated cells generated from human pluripotent cell lines. Other kinds of cell lines are already used in this way. Cancer cell lines, for example, are used to screen potential anti-tumor drugs. But, the availability of pluripotent stem cells would allow drug testing in a wider range of cell types. However, to screen drugs effectively, the conditions must be identical when comparing different drugs. Therefore, scientists will have to be able to precisely control the differentiation of stem cells into the specific cell type on which drugs will be tested. Current knowledge of the signals controlling differentiation fall well short of being able to mimic these conditions precisely to consistently have identical differentiated cells for each drug being tested.

    Perhaps the most important potential application of human stem cells is the generation of cells and tissues that could be used for cell-based therapies. Today, donated organs and tissues are often used to replace ailing or destroyed tissue, but the need for transplantable tissues and organs far outweighs the available supply. Stem cells, directed to differentiate into specific cell types, offer the possibility of a renewable source of replacement cells and tissues to treat diseases including Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
    [​IMG]
    Figure 4. Heart muscle repair with adult stem cells. Click here for larger image.

    For example, it may become possible to generate healthy heart muscle cells in the laboratory and then transplant those cells into patients with chronic heart disease. Preliminary research in mice and other animals indicates that bone marrow stem cells, transplanted into a damaged heart, can generate heart muscle cells and successfully repopulate the heart tissue. Other recent studies in cell culture systems indicate that it may be possible to direct the differentiation of embryonic stem cells or adult bone marrow cells into heart muscle cells (Figure 4).

    In people who suffer from type I diabetes, the cells of the pancreas that normally produce insulin are destroyed by the patient's own immune system. New studies indicate that it may be possible to direct the differentiation of human embryonic stem cells in cell culture to form insulin-producing cells that eventually could be used in transplantation therapy for diabetics.
    To realize the promise of novel cell-based therapies for such pervasive and debilitating diseases, scientists must be able to easily and reproducibly manipulate stem cells so that they possess the necessary characteristics for successful differentiation, transplantation and engraftment. The following is a list of steps in successful cell-based treatments that scientists will have to learn to precisely control to bring such treatments to the clinic. To be useful for transplant purposes, stem cells must be reproducibly made to:
    • Proliferate extensively and generate sufficient quantities of tissue.
    • Differentiate into the desired cell type(s).
    • Survive in the recipient after transplant.
    • Integrate into the surrounding tissue after transplant.
    • Function appropriately for the duration of the recipient's life.
    • Avoid harming the recipient in any way.
    Also, to avoid the problem of immune rejection, scientists are experimenting with different research strategies to generate tissues that will not be rejected.
    To summarize, the promise of stem cell therapies is an exciting one, but significant technical hurdles remain that will only be overcome through years of intensive research.
    The NIH has a wide array of new scientific programs designed to support research that uses embryonic stem cell lines.
     
  3. cheer

    cheer Silver IL'ite

    Messages:
    918
    Likes Received:
    38
    Trophy Points:
    63
    Gender:
    Female
    Stem cell hope for injured spine


    MUMBAI: Gas station worker Ravindra Ahire was completely paralysed and had lost sensation in his lower limbs after his bike skidded on Malegaon's dusty streets. He found hope in Mumbai's Sion Hospital a fortnight later.

    The 24-year-old became the city's first patient with spinal cord injuries to receive stem cell therapy, touted as a panacea for many ills. While hospitals in Chennai, New Delhi and Bangalore have been using stem cells to treat the spine, what sets the Mumbai story apart is the fact that the surgery was conducted in a public hospital and virtually free of cost (public giants All India Institute for Medical Sciences, New Delhi, and PGI, Chandigarh, have tried out stem cell therapy for the heart).

    On April 17, Ravindra's fractured spine was fixed and a dose of stem cells collected from his bone marrow was injected into his ruptured spinal cord, says Dr Alok Sharma, head of Sion Hospital's neurosurgery department who performed the operation. "It's a matter of pride for us that stem cell treatment, available only at a few centres across the world and that too at an exorbitant cost, has been successfully performed at a municipal teaching hospital, that too almost free," says Sharma, who's a senior medical teacher at Sion, one of Mumbai's premier teaching hospitals and research centres and reputed for its trauma-care work.

    Propped up in his corner bed during a physiotherapy session, Ravindra is all smiles. "I can feel when people touch my legs and I have got back my bowel sensations which I did not have before the operation. I have some movement in my hips also," he told TOI in Marathi. Occupational and physical therapists working with him feel Ravindra's improvement has been quicker in comparison to other patients with similar injuries. Ravindra's mother Meerabai is just happy that his pain has subsided for the first time since his accident on April 8.

    The mood in Sion Hospital's neurosurgery department is predictably upbeat. "This is the culmination of 10 years of our research on spinal cord regeneration," says Dr Sharma.

    Stem cell hope for injured spine-Health/Science-The Times of India
     
    2 people like this.
  4. cheer

    cheer Silver IL'ite

    Messages:
    918
    Likes Received:
    38
    Trophy Points:
    63
    Gender:
    Female
  5. aditibose78

    aditibose78 Silver IL'ite

    Messages:
    196
    Likes Received:
    89
    Trophy Points:
    68
    Gender:
    Female
    Hey this is good information. Thanks so much for sharing it here.

    Do read through these features too. They are really a store house of information. I am sure they would answer most of your queries.


    · Understanding the Umbilical Cord
    · Understanding the Different Cord Blood Stem Cell Banking Benefits
    · Stem Cell Banking in India: An Overview
    · Top 3 Stem Cell Banks in India: Which One Should You Go With?

    And here is a big round of cheers to all mommies out there! Congratulations to motherhood :)
     

Share This Page