Month: April 2011

Stable, Self-Renewing Neural Stem Cells


Researchers at the University of California, San Diego School of Medicine, the Gladstone Institutes in San Francisco and colleagues reported a monumental advance in stem cell science: the creation of long-term, self-renewing, primitive neural precursor cells from human embryonic stem cells (hESCs) that can be directed to become many types of neuron without increased risk of tumor formation.

Kang Zhang, professor of ophthalmology and human genetics at Shiley Eye Center and director of the Institute for Genomic Medicine, at UC San Diego said, “It’s a big step forward . . . It means we can generate stable, renewable neural stem cells or downstream products quickly, in great quantities and in a clinical grade – millions in less than a week – that can be used for clinical trials and, eventually, for clinical treatments. Until now, that has not been possible.”

Human embryonic stem cells can become any kind of cell needed to repair and restore damaged tissues, and for this reason, a great deal of hope has been placed in them when it comes to regenerative medicine. But the potential of hESCs is constrained by practical problems, not least of which is the difficulty of growing sufficient quantities of stable, usable cells and the risk that some of these cells might form tumors.

To produce neural stem cells, Zhang, with co-author Sheng Ding, former professor of chemistry at The Scripps Research Institute and now at the Gladstone Institutes, and their colleagues added small molecules in a chemically defined culture condition that induces hESCs to become primitive neural precursor cells, but then halts further differentiation processes.

Zhang added, “And because it doesn’t use any gene transfer technologies or exogenous cell products, there’s minimal risk of introducing mutations or outside contamination.” Assays of these neural precursor cells found no evidence of tumor formation when introduced into laboratory mice.

By adding other chemicals, scientists were able to then direct the precursor cells to differentiate into different types of mature neurons. This means that you can explore potential clinical applications for a wide range of neurodegenerative diseases. You can generate neurons for specific conditions like amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), Parkinson’s disease or eye-specific neurons that are lost in macular degeneration, retinitis pigmentosa or glaucoma.

The new process promises to have broad applications in stem cell research. The same method can be used to push induce pluripotent stem cells (stem cells artificially derived from adult, differentiated mature cells) to become neural stem cells. In principle, by altering the combination of small molecules, you might be able to create other types of stem cells capable of becoming heart, pancreas, or muscle cells. The next step is to use these stem cells to treat different types of neurodegenerative diseases, such as macular degeneration or glaucoma in animal models.

One problem this study does not address is the immunological rejection of implanted stem cells.  Deriving such cells from induced pluripotent stem cells would be a much more desirable and practical technology from a clinical standpoint.  Also, the use of induced pluripotent stem cells would not require the death of anymore young human beings.

More Patient Results for Hip and Knee Arthritis treated with Stem Cell and Platelet Injections


A 61-year old financial strategist from New York city who stepped off a curb in 2005 and tore the meniscus in her right knee. After surgery (partial menisectomy), her condition worsened. Due to changes in her walking style from the pain in the right knee, her left hip began hurting. She was able to get around New York on foot only with an unloader brace and had difficulty with walking long distances. What did she do? Read about the rest here.

A universal method for converting blood-making stem cells into heart cells


Scientists from the Johns Hopkins University have developed a simplified, cheaper, all-purpose method that might be usable to more safely turn blood cells into heart cells. This method is virus-free and produces heart cells that beat with nearly 100 percent efficiency. Elias Zambidis, M.D., Ph.D., assistant professor of oncology and pediatrics at the Johns Hopkins Institute for Cell Engineering and the Kimmel Cancer Center said, “We took the recipe for this process from a complex minestrone to a simple miso soup.” Continuing, Zambidis added, “many scientists previously thought that a nonviral method of inducing blood cells to turn into highly functioning cardiac cells was not within reach, but “we’ve found a way to do it very efficiently and we want other scientists to test the method in their own labs.” However, he cautions that the cells are not yet ready for human testing.

In order to transform cells from one cell type to another, scientists generally use engineered viruses to deliver genes into cells to convert them into different cell types or to turn them into induced pluripotent stem cells. Viruses, however, come with several caveats, the most prevalent of which is the ability of viruses to insert into genes and cause mutations. Some of these mutations can even cause the types of mutations that can initiate cancer-like growth in transformed cells. To insert the genes without using a virus, Zambidis’ team turned to small circles of DNA called plasmids. Once introduced into cells, these rings of DNA replicate only briefly inside cells after which, they are degraded.

If this isn’t bad enough, coaxing stem cells into other cell types is also expensive because of the varied recipe of growth factors, nutrients and conditions that are used to grow stem cells during their transformation. The recipe of this “broth” differs from lab to lab and cell line to cell line. However, Zambidis’ team described what he called a “painstaking, two-year process” to simplify the recipe and environmental conditions that are used to grow cells that are undergoing transformation into heart cells. They found that their recipe worked consistently for at least 11 different stem cell lines tested. They also found that it worked equally well for the embryonic stem cells, and stem cell lines made from adult blood stem cells (this was reported in the April 8 issue of Public Library of Science ONE (PLoS ONE).

How to convert these cells into heart cells? Postdoctoral scientist Paul Burridge examined some 30 papers on techniques to create cardiac cells. After drawing charts of 48 different variables in the creation of heart cells, he tested hundreds of combinations of these variables. Burridge eventually narrowed the choices down to between four to nine essential ingredients at each of three stages of cardiac development. This simplified the protocol for making heart cells, but it had an added benefit: Burridge’s recipe was one-tenth the price of standard media for these cells ($250 per bottle lasting about one week).

Zambidis says that he wants other scientists to test the method on their stem cell lines, but also notes that the growth “soup” is still a work in progress. “We have recently optimized the conditions for complete removal of the fetal bovine serum from one brief step of the procedure – it’s made from an animal product and could introduce unwanted viruses,” he says.

In their experiments, the Hopkins team tested their new growth medium on cord blood stem cells. They used electric pulses to transfer a plasmid into the cells. These plasmids transferred seven genes into the stem cells. These plasmids triggered the cells to revert to a more primitive cell state (induced pluripotent stem cells or iPSCs). Then Burridge bathed the newly formed iPSCs in the simplified recipe of growth media, which they named “universal cardiac differentiation system.” Finally, they incubated the cells in containers that removed oxygen down to a quarter of ordinary atmospheric levels. Burridge noted, “The idea is to recreate conditions experienced by an embryo when these primitive cells are developing into different cell types.” Nine days later, these cells formed clumps of functional, beating cardiac cells, each the size of a needlepoint. Burridge determined that an average of 94.5% of the iPSCs had formed cardiac cells in Petri dishes. Most scientists see an efficiency of 10% on a good day.

Physiological studies showed that these cardiac cells showed the same characteristic muscular pulses seen in a normal human heart. Therefore, virus-free, iPSC-derived cardiac cells could be used in laboratories to test drugs that treat arrhythmia and other conditions. Perhaps, such cells could eventually be engineered to develop grafts of the cells that are implanted into patients who suffered heart attacks.

Zambidis’ team has recently developed similar techniques for turning these blood-derived iPSC lines into retinal, neural and vascular cells.

Umbilical stem cells treat lupus-induced kidney disease


Systemic lupus erythematosis, a disease in which the immune system attacks the very body that houses it, is more commonly known as lupus. This disease has ravaged the bodies and lives of many people who were once healthy and active and reduced them to shells of their former selves. Little is available for lupus suffers. Drugs range from drugs that suppress the immune system like steroids or antimalarial drugs like hydroxychloroquine (Plaquenil) that are better tolerated, but still have many undesirable side effects. Lupus patients expect little more than a steady decline that culminates in a rather unpleasant death.

Now stem cells seem to offer some of the first hope for lupus patients. Human umbilical cord blood-derived mesenchymal stem cells (uMSCs) seem to offer some benefits as a treatment for lupus nephritis (LN). Mice that suffer from a disease is very similar to the human lupus disease were given transplantations of uMSCs showed improvements. This is a very welcomed result for the thousands of lupus sufferers. Lupus is an autoimmune disease characterized by aberrations of the immune response, but it results in a diversity of clinical conditions, including LN, which is a leading cause of morbidity and mortality for lupus patients.

Corresponding author Dr. Oscar K. Lee of the National Yang-Ming University School of Medicine stated that MSCs have been shown to possess the ability to turn down the immune system. They can inhibit inflammation and mediate the function of mature and immature immune system T cells. To determine if MSCs from umbilical cord can provide some therapeutic relief for LN, Lee and his colleagues transplanted umbilical cord blood-derived stem cells into mice engineered to develop a disease that closely resembles lupus in humans.

The results, according to Lee, showed that “uMSC transplantation markedly delayed the deterioration of renal function, reduced certain antibody levels, alleviated changes in renal pathology and the development of proteinuria – the presence of excess protein serum in the urine and a sign of renal damage.” The positive difference in survival rate for mice treated at two months of age compared with mice treated at six months of age, led the researchers to conclude that early uMSC transplantation are more effective than later transplantations. The researchers also deduced that their findings favored the use of allogenic (other-donated) rather than autologous (self-donated) MSCs for SLE treatment, which would make sense with an autoimmune disorder. “The therapeutic effects demonstrated in this pre-clinical study support further exploration of the possibility of using uMSCs from mismatched donors in LN treatment,” concluded Dr. Lee.

The beneficial results were in the current issue of Cell Transplantation (20:1). Dr. David Eve, associate editor of CELL TRANSPLANTATION and an instructor at the University of South Florida Center of Excellence for Aging and Brain Repair, said, “The ability of uMSCs to reduce inflammation means that they are likely to be of use in the treatment of autoimmune disorders and this study supports that reasoning and, in this case, also advocates the use of non-self cells.

Stem Cell Switch Can Heal Skin


Recent work at King’s College London and Osaka University, Japan has shown that bone marrow stem cells can differentiate into mature skin cells and repair damaged skin. This finding could provide a remarkable benefit to people with chronic wounds like leg ulcers, burns and pressure sores. Likewise, victims of genetic diseases that affect the skin like epidermolysis bullosa, which causes painful blisters on the skin, might also be treatable with this procedure.

These scientists took advantage of the finding that bone marrow probably plays a role in skin wound healing. However, this work makes it clear that specific bone marrow stem cells are involved in wound healing, and this work also identified the specific triggers that recruit these particular skin cells to the affected skin area.

These research teams examines mice with skin damage and compared the healing mechanisms involved when skin grafts are used, compared with those mechanisms used in non-grafted wound healing. The findings showed that in mice with non-grafted wound healing, very few bone marrow cells traveled to the wound to repair it and did not make a major contribution to epidermal repair. However in mice where a skin graft was used, a significantly higher number of specific bone marrow-derived cells traveled to the skin graft to heal the area more quickly and build new skin directly from the bone marrow cells.

Amazingly, the research showed that around one in every 450 bone marrow cells has the capacity to become a skin cell and regenerate the skin. Also, the trigger that recruits the bone marrow cells to repair skin is a protein called HMGB1, which is made by damaged skin. HMGB1 mobilizes the cells from bone marrow and directs them to where they need to go to heal the damage. Mice with skin grafts express high levels of HMGB1 in their blood, and this protein drives the bone marrow repair process. These findings provide new insight into how skin grafts work in medicine. They do not simply cover wounds; instead they act as bioreactors that potentially kick-start regenerative skin repair.

Patients who suffer from the genetic disease epidermolysis bullosa also express high levels of HMGB1 in their blood. Furthermore, the source of this HMGB1 is the roofs of the blisters in their skin. This demonstrates that HMGB1 is also important in human skin damage and wound healing responses.

John McGrath, leader of the Genetic Skin Disease Group at King’s College said, “This work is tremendously exciting for the field of regenerative medicine. The key achievement has been to find out which bone marrow cells can transform into skin cells and repair and maintain the skin as healthy tissue, and to learn how this process happens. . . Understanding how the protein HMGB1 works as a distress signal to summon these particular bone marrow cells is expected to have significant implications for clinical medicine, and could potentially revolutionize the management of wound healing.”

McGrath is working together with colleagues at Osaka Univ. to harness the key parts of the HMGB1 protein to create a drug treatment that can augment tissue repair. Clinical trials that test this treatment protocol in humans rather than animal models is a distinct probability. This research was published in the journal in Proceedings of the National Academy of Sciences.