Adult vs. Embryonic Stem Cells

Adult Stem Cells

Immunological Challenges for Stem Cells

Stem cells transmit a vast potential for treating disease but they also come with hurdles that must be overcome to ensure their success and viability for treating disease. One challenging area is that involving a patient's immune system. The challenges are also unusual because they mostly pertain to embryonic stem cells whereas adult stem cells can actually alleviate immunological challenges that tend to accompany embryonic stem cells. It's important to understand what exactly happens during immune rejection before looking at the different immunological consequences from use of embryonic stem cells.

Just how Alcohol Affects Stem Cells

Alcohol is known to cause several health difficulties but new research shows it can affect stem cells too. In particular, a recent study suggests alcohol damages stem cells in the developing brains of teenagers.

Anxieties about Stem Cells

Stem cells

Despite the enormous therapeutic potential for stem cells to treat a vast array of serious diseases there are still concerns about potentially dangerous results. Scientists are excited about the possibilities of saving lives and reducing morbidity from disease but at the same time, there are fears regarding unexpected results and effects from stem cell usage. With recent technologies having triggered a major increase in stem cell treatments, the concept of stem cell therapies is no longer such a foreign one.

Pluripotent Stem Cells

Moving toward regeneration

Sept. 1, 2012—the skin, the blood, and the lining of the gut—adult stem cells replenish them daily. But stem cells really show off their healing powers in planarians, humble flatworms fabled for their ability to rebuild any missing body part. Just how adult stem cells build the right tissues at the right times and places has remained largely unanswered.

Now, in a study published in an upcoming issue of Development, researchers at the Stowers Institute for Medical Research describe a novel system that allowed them to track stem cells in the flatworm Schmidtea mediterranea. The team found that the worms' stem cells, known as neoblasts, march out, multiply, and start rebuilding tissues lost to amputation.

Definition of Human pluripotent stem cell

Human pluripotent stem cell: One of the "cells that are self-replicating, are derived from human embryos or human fetal tissue, and are known to develop into cells and tissues of the three primary germ layers. Although human pluripotent stem cells may be derived from embryos or fetal tissue, such stem cells are not themselves embryos." (From the National Institutes of Health Guidelines for Research Using Human Pluripotent Stem Cells.)

Pluripotent Stem Cells

The concept of stem cells can seem a complicated one and you may have seen foreign words such as 'pluripotent' written in magazines or discussed on television. Stem cells describe all of the cells that can give rise to the different cells found in tissues. There are however, different types of stem cells. One such type is a pluripotent stem cell.

What Are Pluripotent Stem Cells?

Pluripotent stem cells are often termed 'true' stem cells because they have the potential to differentiate into almost any cell in the body. This means that under the right circumstances, a stem cell that is isolated from an embryo can produce almost all of the cells in the body. Yet after this embryonic development stage is over, the stem cells no longer have this unlimited potential to develop into all cell types. Their pluripotency is thus lost and they can only become certain types of cells.

Hearts of Hope: Stem Cell Therapies to Cure Heart Diseases

“That’s the scary thing about heart disease. You can be fine one minute and dead the next. You can put up with a little chest pain every once in a while if you know you’re not about to die from it.” - Mark Hlatky

Heart attacks and congestive heart failure remain among the world’s most prominent health challenges, despite many breakthroughs in cardiovascular medicine.

Out of 1 million people in the U.S. Who suffer from chronic, severe angina (chest pain due to blocked arteries), about 300,000 cannot be helped by any traditional medical treatment such as angioplasty. The destruction of heart muscle cells is the result of hypertension, a chronic insufficiency of blood supply to the heart muscle due to a sudden closing of a blood vessel supplying oxygen to the heart. Also, cardiomyocytes, i.E. Cells in the heart muscles that contract to eject the blood out of the heart’s main pumping chamber (ventricle), has a large demand for blood flow. Thus, specialized cells are important for shifting the injured heart muscle cells from a quiescent state into active cell division, and developing a new network of arteries to transport nutrients and oxygen. For this reason, stem celltherapy has been the hope for many patients with heart disease.

Stem cells can self-renew and differentiate into specialized cell types, and thus are receiving much attention for the great potential to be used for regenerative medicine and tissue therapy . Stem cells can be retrieved from discarded embryos, umbilical cord, placenta after birth, adipose tissue, bone marrow, and mesenchymal cells. In addition to embryonic stem cells and adult stem cells, induced pluripotent stem cells (iPSCs) can be prepared by reprogramming cellular processes through introducing transcription factors .

On July 1, 2011, the Korea Food and Drug Administration (KFDA) approved for the first time in the world a stem cell therapeutic for the acute myocardial infarction after a successful clinical trial . It uses autologous bone marrow-derived mesenchymal stem cells, and has been approved for the improvement of left ventricular ejection fraction in patients who underwent percutaneous transluminal coronary angiography within 72 hours after the onset of chest pain.

Although the very first stem cell product in the world has been approved for treating heart disease , there are still pending uncertainties and practical limitations in the use of stem cells as therapeutics. First, more diverse, large-scale clinical trials should be conducted so that safety and efficacy are guaranteed. It needs to be seen whether stem cells can be genetically programmed to migrate directly to the site of injury and immediately synthesize heart proteins necessary for the regeneration process. Other challenges to overcome include preventing immune rejection by patients of stem cells prepared non-autologously, securing umbilical cord blood from a baby at the time of birth for later use without affecting child’s health, and developing iPSCs without using viral vectors and oncogenes.

Obviously, the aforementioned scientific challenges cannot stop the stem cells from being used to treat heart disease in the near future; millions are waiting for their hearts to become healthy again. Patients worldwide will continue to anticipate the rise of stem cell treatment as a popularized therapy, until everyone gets to cure their long fought diseases.

Read Full Article: Hearts of Hope: Stem Cell Therapies to Cure Heart Diseases

Stem cell shield 'could protect cancer patients'

The trial is being conducted on patients with brain cancer. The photo is taken from BBC website.BBC Online

It may be possible to use "stem cell shielding" to protect the body from the damaging effects of chemotherapy, early results from a US trial suggest.

Chemotherapy drugs try to kill rapidly dividing cancer cells, but they can also affect other healthy tissues such as bone marrow.

A study, in Science Translational Medicine, used genetically modified stem cells to protect the bone marrow.

Cancer Research UK said it was a "completely new approach".

The body constantly churns out new blood cells in the hollow spaces inside bone. However, bone marrow is incredibly susceptible to chemotherapy.

The treatment results in fewer white blood cells being produced, which increases the risk of infection, and fewer red blood cells, which leads to shortness of breath and tiredness.

Researchers at the Fred Hutchinson Cancer Research Center, in Seattle, said these effects were "a major barrier" to using chemotherapy and often meant the treatment had to be stopped, delayed or reduced.

'Protective shields'

They have tried to protect the bone marrow in three patients with a type of brain cancer, glioblastoma.

One of the researchers, Dr Jennifer Adair, said: "This therapy is analogous to firing at both tumour cells and bone marrow cells, but giving the bone marrow cells protective shields while the tumour cells are unshielded."

Bone marrow was taken from the patients and stem cells, which produce blood, were isolated. A virus was then used to infect the cells with a gene which protected the cells against a chemotherapy drug. The cells were then put back into the patient.

The lead author of the report, Prof Hans-Peter Kiem, said: "We found that patients were able to tolerate the chemotherapy better, and without negative side effects, after transplantation of the gene-modified stem cells than patients in previous studies who received the same type of chemotherapy without a transplant of gene-modified stem cells."

The researchers said the three patients had all lived longer than the average survival time of 12 months for the cancer. They said one patient was still alive 34 months after treatment.

Cancer Research UK scientist Prof Susan Short said: "This is a very interesting study and a completely new approach to protecting normal cells during cancer treatment.

"It needs to be tested in more patients but it may mean that we can use temozolomide [a chemotherapy drug] for more brain tumour patients than we previously thought.

"This approach could also be a model for other situations where the bone marrow is affected by cancer treatment."

Read Full Article: Stem cell shield 'could protect cancerpatients'

stem_cell_guidelines

stem_cell_guidelines(pdf)