Stem Cell Research

How Bone Marrow Stem Cells Injected Into Skeletal Muscle Reverse Heart Failure

In another step toward a stem cell therapy, researchers have identified a growth-factor chain of action that prompts bone marrow stem cells to repair cardiac tissue and reverse heart failure.

Earlier this researcg group showed that injecting bone marrow mesenchymal stem cells into skeletal muscle in an animal model increased two-fold the production of myocytes, a type of heart muscle cell.

"By thoroughly understanding the interplay of stem cells and host tissue, and characterizing stem-cell-derived growth factors," said Techung Lee, PhD, associate professor of biochemistry and biomedical engineering in the New York University at Buffalo School of Medicine and Biomedical Sciences. "it is possible to assemble a cocktail of these factors and use it for tissue repair, much like the use of insulin for diabetes patients."

Researchers Engineer Adult Stem Cells That Do Not Age

Researchers have created these new cell lines – named Mesenchymal Stem Cell Universal or MSC Universal – by genetically altering mesenchymal stem cells from bone marrow. These stem cells are known to differentiate into cell types including bone, cartilage, muscle, fat, and beta-pancreatic islet cells. This breakthrough overcomes a frustrating barrier to progress in the field of regenerative medicine: The difficulty of growing adult stem cells for clinical applications.

Until now, mesenchymal stem cells have had a limited life span in laboratory cultures. Scientists and doctors who use the cells in research and stem cell therapies must continuously obtain fresh samples from bone marrow donors, a process both expensive and time-consuming. An additional problem is that mesenchymal stem cells from different donors can vary in performance.

Fat Stem Cells Found Safe for Breast Reconstruction Only when Cancer is Dormant

Plastic surgeons have long moved fat from one part of the body into the breasts for reconstruction, but with some complications and a varying success rate. 

More recently, they have considered adding stem cells derived from adipose, or fat, tissue (ADSC) or the bone marrow to the transferred fat with the aim of supporting graft integration by enhancing new blood vessel formation.

“But it has not been clear whether these stem cells are safe for breast cancer patients because they could send growth signals that promote tumor reactivation or provide new blood vessels for the tumor,” explained Vera S. Donnenberg, Ph.D., assistant professor of surgery, Pitt School of Medicine.  “Our research suggests that this risk is real if the patient still has active tumor cells, but is safe when the cells are inactive or resting.”

First U.S. Trial Of Bone-Marrow Stem Cell Therapy For Heart Attack Proves Safe

The first randomized, placebo-controlled U.S. clinical trial to assess the use of bone marrow-derived mononuclear cells (BMC) in patients after a ST-elevation myocardial infarction (STEMI; severe heart attack) demonstrated a strong safety profile for this cell therapy, based on phase I results.

In this single-center trial, the researchers enrolled 40 patients with STEMI, randomizing them in a 3:1 ratio to 100 million autologous BMCs versus placebo, administered three to ten days following successful primary angioplasty and stenting of the left anterior descending coronary artery. Importantly, the researchers elected to deliver cells by an intracoronary infusion as opposed to the stop-flow technique that had been used in all preceding trials. All patients received an identical number of cells.

"The use of adult stem cells, derived from the patient's own bone marrow, presents a potential new type of therapy to benefit individuals after they suffer a heart attack," said principal investigator Jay H. Traverse, MD, cardiologist at the Minneapolis Heart Institute at Abbott Northwestern Hospital in Minneapolis, Minn. "Also, these types of stem cells do not possess any of the ethical concerns of embryonic stem cell research."

Researchers Find Solution to Cell Death Problem Vexing Stem Cell Research

Human pluripotent stem (hPS) cells can generate any given cell type in the adult human body, which is why they are of interest to stem cell scientists working on finding stem cell therapies for spinal cord injuries, Parkinson's disease, burns, heart disease, diabetes, arthritis, and other ailments.

Before hPS cell technologies can be translated into clinical applications, however, some obstacles must first be overcome.

One such obstacle frustrating stem cell researchers is “cell death” that the major types of hPS cells, including human embryonic stem cells and human induced pluripotent stem cells, mysteriously undergo when cultured as single cells, rendering them less suitable for research.

Researchers at the University of California, Riverside now show that a molecular motor, called “nonmuscle myosin II” (NMII), which exists naturally inside each hPS cell and controls various cellular functions, triggers the death of hPS cells when they are broken down to single cells.

While many details of how exactly NMII works remain unknown, a wide consensus among researchers is that NMII induces a contraction of the main internal components of the cells, eventually resulting in cell death.

Researchers Identify how Bone-Marrow Adult Stem Cells Hold Their 'Breath' In Low-Oxygen Environments

Researchers have found that the low-oxygen microenvironments that ordinarily deprive and starve other kinds of cells are tolerated by a type of stem cell used as the primary material for bone-marrow transplantation.

"Our findings highlight important characteristics of bone-marrow stem cells that make them more likely to survive in the low-oxygen environments present, for example, after a heart attack," said Dr. Hesham Sadek, assistant professor of internal medicine at UT Southwestern. "These findings may also be exploited to enrich bone-marrow stem and progenitor cells by selecting cells based on their metabolic properties."

These cells, called hematopoietic stem cells, are found in marrow and can replicate quickly. Once transplanted, they eventually develop into blood and other types of cells. Their ability to self-renew before they transform into blood forms the basis of their usefulness for bone-marrow transplants.

"The cells convert glucose, or sugars, into energy rather than using oxygen to release energy," said Dr. Sadek. "They use glycolysis instead of mitochondrial oxidative phosphorylation to meet their energy demands."