Stem Cells: The God Source

Chapter 1

What Are Stem Cells

Stem Cells are unlike any other adult cells and have a very special and unique characteristic to self-replicate and duplicate themselves over and over as needed.

I. Stem Cells The Beginning

It has been said, stem cells are the trigger to the fountain of youth and longevity. The true doorway to a new understanding and unlimited universe of reproductive repair, healing and youth regeneration. Stem cells are very unique and the foundation for every organ and tissue in your body. There are different types of stem cells that come from different places in the body and form at different times in our lives.

These include embryonic stem cells that exist only at the earliest stages of life development and other various types called adult stem cells that appear during fetal development and remain in our bodies throughout life.

All stem cells have the capacity to replicate and copy themselves over and over as they differentiate, develop into more specialized cells as needed and required to sustain the life form. Stem cells vary widely in what they can and cannot do through life, this is one of the reasons researchers use all types of stem cells in their investigations to uncover the unlimited potential. Stem cells of the body are called somatic cells, which divide and become differentiated.

When an organism grows, stem cells specialize in a specific function and assist the organism to grow and mature fully, for instance, mature tissues like skin, muscle, blood, bone, liver, nerves, all have specific types of cells.

Whereas stem cells are special neutral human cells that also have the ability to repair damaged tissues and become new cells as needed.

This is an exciting time in science and health and most likely a different game changer on the planet in the realm of new medical healing short cuts and discoveries. The first and foremost exciting area in medicine is because of their potential to regenerate and repair damaged tissue. Some current therapies, such as bone marrow transplantation, already make use of stem cells and their potential for regeneration of damaged tissues.

The Importance of Stem Cells

Stem cells are most important and have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person is still alive. When a stem cell divides, each new cell has the potential either to 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. Stem cells are distinguished from other cell types by two important characteristics.

First, they are unspecialized cells capable of renewing themselves through what is called cell division even after unusually long periods of inactivity.

Second, under certain physiologic or experimental conditions, they can be induced to become tissue or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.

Information Sourced

1981

Researchers and Scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and somatic (adult) stem cells. The functions and characteristics of these cells are derived from embryonic stem cells research in mice embryos, in 1981.

1998

The detailed study of the biology of mouse stem cells led to the discovery, in 1998 of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem. The embryos used in these studies were created for reproductive purposes through a technique called fertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor.

2006

In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be reprogrammed genetically to assume a stem cell-like state. This new type of stem cell, called, induced pluripotent stem cells or, iPSC.

Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lungs, skin, sperm, eggs 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.

Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.

Laboratory studies of stem cells enable scientists to learn about the cells’ essential properties and what makes them different from specialized cell types. Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects.

Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.

II. The Unique Properties of All Stem Cells

Some Stem cells differ from other kinds of cells in the body. All stem cells—regardless of their source—have three general properties: they are capable of dividing and renewing themselves for long periods; they are unspecialized; and they can give rise to specialized cell types.

Stem cells are capable of dividing and renewing themselves for long periods. Unlike muscle cells, blood cells, or nerve cells—which do not normally replicate themselves—stem cells may replicate many times or proliferate. A starting population of stem cells that proliferates for many months in the laboratory can yield millions of cells. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells are said to be capable of long-term self-renewal.

Scientists are trying to understand two fundamental properties of stem cells that relate to their long-term self-renewal:

1. Why can embryonic stem cells proliferate for a year or more in the laboratory without differentiating, why most adult stem cells cannot?

2. What are the factors in living organisms that normally regulate stem cell proliferation and self-renewal?

Discovering the answers to these questions may make it possible to understand how cell proliferation is regulated during normal embryonic development or during the abnormal cell division that leads to cancer. Such information would also enable scientists to grow embryonic and non-embryonic stem cells more efficiently in the laboratory.

The specific factors and conditions that allow stem cells to remain unspecialized are of great interest to scientists. It has taken scientists many years of trial and error to learn to derive and maintain stem cells in the laboratory without them spontaneously differentiating into specific cell types. For example, it took two decades to learn how to grow human embryonic stem cells in the laboratory following the development of conditions for growing mouse stem cells. Likewise, scientists must first understand the signals that enable a non-embryonic (adult) stem cell population to proliferate and remain unspecialized before they will be able to grow large numbers of unspecialized adult stem cells in the laboratory.

Stem cells are unspecialized and act randomly. One of the fundamental properties of a stem cell is that it does not have any tissue-specific structures that allow it to perform specialized functions. For example, a stem cell cannot work with its neighbors to pump blood through the body (like a heart muscle cell), and it cannot carry oxygen molecules through the bloodstream (like a red blood cell). However, unspecialized stem cells can give rise to specialized cells, including heart muscle cells, blood cells, or nerve cells.

Stem cells can assist and then give rise to certain specialized cells. When unspecialized stem cells give rise to specialized cells, the process is called differentiation.

When the stem cells are in process of differentiating, the cell usually goes through several stages, becoming more specialized at each step. Scientists are just beginning to understand the signals inside and outside cells that trigger each step of the differentiation process. The internal signals are controlled by a cell's genes, which are interspersed across long strands of DNA and carry coded instructions for all cellular structures and functions. The external signals for cell differentiation include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment.

The interaction of signals during differentiation causes the cell's DNA to acquire epigenetic marks that restrict DNA expression in the cell and can be passed on through cell division.

Many questions about stem cell differentiation remain. For example, are the internal and external signals for cell differentiation similar for all kinds of stem cells? Can specific sets of signals be identified that promote differentiation into specific cell types? Addressing these questions may lead scientists to find new ways to control stem cell differentiation in the laboratory, thereby growing cells or tissues that can be used for specific purposes such as stem cell-based therapies on using pharmaceutical drug screening.

Adult stem cells typically generate the cell types of the tissue in which they reside. For example, a blood-forming adult stem cell in the bone marrow normally gives rise to the many types of blood cells. It is generally accepted that a blood-forming cell in the bone marrow—which is called a hematopoietic stem cell which cannot give rise to the cells of a very different tissue, such as nerve cells in the brain. Experiments over the last several years have purported to show that stem cells from one tissue may give rise to cell types of a completely different tissue. This remains an area of great debate within the research community. This controversy demonstrates the challenges of studying adult stem cells and suggests that additional research using adult stem cells is necessary to understand their full potential as future therapies.

III. Embryonic stem cells

A. What stages of early embryonic development are important for generating embryonic stem cells?

This is in reference to Embryonic stem cells, as their name suggests, are derived from embryos. Most embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in-vitro in an in vitro fertilization clinic and then donated for research purposes with informed consent of the donors. They are not derived from eggs fertilized in a woman's body.

B. How are embryonic stem cells grown in the laboratory?

Growing cells in the laboratory is known as cell culture. Human embryonic stem cells (HESCs) are generated by transferring cells from a preimplantation stage embryo into a plastic laboratory culture dish that contains a nutrient broth known as culture medium. The cells divide and spread over the surface of the dish. In the original protocol, the inner surface of the culture dish was coated with mouse embryonic skin cells specially treated so they will not divide. This coating layer of cells is called a feeder layer. The mouse cells in the bottom of the culture dish provide the cells a sticky surface to which they can attach. Also, the feeder cells release nutrients into the culture medium. Researchers have now devised ways to grow embryonic stem cells without mouse feeder cells. This is a significant scientific advance because of the risk that viruses or other macromolecules in the mouse cells may be transmitted to the human cells.

The process of generating an embryonic stem cell line is somewhat inefficient, so lines are not produced each time cells from the preimplantation-stage embryo are