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Posts Tagged ‘regeneration’

EPIDERMAL GROWTH FACTOR INCREAESES STEM CELL REGENERATION AFTER RADIATION

In ALL ARTICLES, SCIENCE & STEM CELLS on February 6, 2013 at 9:00 am

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Growth Factor Aids Stem Cell Regeneration After Radiation Damage

Epidermal growth factor has been found to speed the recovery of blood-making stem cells after exposure to radiation, according to Duke Medicine researchers. The finding could open new options for treating cancer patients and victims of dirty bombs or nuclear disasters.

Reported in the Feb. 3, 2013, issue of the journal Nature Medicine, the researchers explored what had first appeared to be an anomaly among certain genetically modified mice with an abundance of epidermal growth factor in their bone marrow. The mice were protected from radiation damage, and the researchers questioned how this occurred.

“Epidermal growth factor was not known to stimulate hematopoiesis, which is the formation of blood components derived from hematopoietic stem cells,” said senior author John Chute, M.D., a professor of medicine and professor of pharmacology and cancer biology at Duke University. “However, our studies demonstrate that the epidermal growth promotes hematopoietic stem cell growth and regeneration after injury.”  Hematopoietic stem cells, which constantly churn out new blood and immune cells, are highly sensitive to radiation damage. Protecting these cells or improving their regeneration after injury could  benefit patients who are undergoing bone marrow transplantation, plus others who suffer radiation injury from accidental environmental exposures such as the Japanese nuclear disaster in 2011.”

The Duke researchers launched their investigation using mice specially bred with deletions of two genes that regulate the death of endothelial cells, which line the inner surface of blood vessels and are thought to regulate the fate of hematopoietic stem cells. Blood vessels and the hematopoietic system in these mice were less damaged when exposed to high doses of radiation, improving their survival.  An analysis of secretions from bone marrow endothelial cells of the protected mice showed that epidermal growth factor (EGF) was significantly elevated — up to 18-fold higher than what was found in the serum of control mice.  The researchers then tested whether EGF could directly spur the growth of stem cells in irradiated bone marrow cultured in the lab. It did, with significant recovery of stem cells capable of repopulating transplanted mice.  Next, the Duke team tried the approach in mice using three different solutions of cells in animals undergoing bone marrow transplants. One group received regular bone marrow cells; a second group got bone marrow cells from donors that had been irradiated and treated with EGF; a third group got bone marrow cells from irradiated donors treated with saline.  The regular bone marrow cells proliferated well and had the highest rate of engraftment in the recipient mice. But mice that were transplanted with the cells from irradiated/EGF-treated donors had 20-fold higher engraftment rate than the third group.

Additional studies showed that EGF improved survival from a lethal radiation exposure, with 93 percent of mice surviving the radiation dose if they subsequently received treatment with EGF, compared to 53 percent surviving after treatment with a saline solution.

Chute said it appears that EGF works by repressing a protein called PUMA that normally triggers stem cell death following radiation exposure.

“We are just beginning to understand the mechanisms through which EGF promotes stem cell regeneration after radiation injury,” Chute said. “This study suggests that EGF might have potential to accelerate the recovery of the blood system in patients treated with chemotherapy or radiation.”

Source:  Duke Health.org

Stem cell transplants help kidney damage

In ALL ARTICLES on February 18, 2011 at 10:13 am

“Transplanting autologous renal progenitor cells (RPCs), (kidney stem cells derived from self-donors), into rat models with kidney damage from pyelonephritis – a type of urinary infection that has reached the kidney – has been found to improve kidney structure and function.”

Stem cell transplants help kidney damage

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Tampa, Fla. (Feb. 14, 2011) – Transplanting autologous renal progenitor cells (RPCs), (kidney stem cells derived from self-donors), into rat models with kidney damage from pyelonephritis – a type of urinary infection that has reached the kidney – has been found to improve kidney structure and function.

The study, authored by a research team from the Tehran University of Medical Sciences, is published in the current issue of Cell Medicine [1(3)] and is freely available on-line at: http://www.ingentaconnect.com/content/cog/cm .

“Advancements in stem cell therapies and tissue engineering hold great promise for regenerative nephrology,” said Dr. Abdol-Mohammad Kajbafzadeh, corresponding author. “Our RPC transplant study demonstrated benefits for pyelonephritis, a disease characterized by severe inflammation, renal function impairment and eventual scarring, and which remains a major cause of end-stage-renal disease worldwide.”

The researchers divided 27 rats into three groups, two of which were modeled with an induced pyelonephritis in their right kidneys, while the third group did not have induced disease. RPCs were obtained from the diseased animals’ left kidneys and injected into the right kidney six weeks later. Two weeks after injection, tubular atrophy was reduced. After four weeks, fibrosis was reduced and after sixty days, right renal tissue integrity was “significantly improved.”

“We propose that kidney augmentation was mainly due to functional tissue regeneration following cellular transplantation,” said Dr. Kajbafzadeh. “Kidney-specific stem/progenitor cells might be the most appropriate candidates for transplantation because of their inherent organ-specific differentiation and their capacity to modulate tissue remodeling in chronic nephropathies.”

The researchers concluded that because renal fibrosis is a common and ultimate pathway leading to end-stage renal disease, amelioration of fibrosis might be of major clinical relevance.

“Transplanting RPCs showed the potential for partial augmentation of kidney structure and function in pyelonephritis,” said Dr. Kajbafzadeh. “This is one of the first studies to demonstrate improved renal function after cell transplantation. The translation of this study into larger clinical models will be very relevant to validate the success of this small animal study.” said Dr. Amit Patel, Section Editor Cell Medicine, Associate Professor of Surgery, University of Utah.

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Citation. Kajbafzadeh, A-M.; Elmi, A.; Talab, S. S.; Sadeghi, Z.; Emami, H.; Sotoudeh, M. Autografting of Renal Progenitor Cells Ameliorates Kidney Damage in Experimental Model of Pyelonephritis. Cell Med. 1(3): 115-122; 2010.

Stem cell transplants help kidney damage

STEM CELLS IN HAIR = NEW ORGANS

In ALL ARTICLES, STEM CELLS IN THE NEWS on February 13, 2009 at 10:36 pm
HAIR FOLLICLES

HAIR FOLLICLE ROOTS

Stem Cells In Hair Follicles Point To General Model Of Organ Regeneration

ScienceDaily (Feb. 13, 2009) — Most people consider hair as a purely cosmetic part of their lives. To others, it may help uncover one of nature’s best-kept secrets: the body’s ability to regenerate organs. Now, new research from Rockefeller University gets to the root of the problem, revealing that a structure at the base of each strand of hair, the hair follicle, uses a two-step mechanism to activate its stem cells and order them to divide.

The mechanism provides insights into how repositories of stem cells may be organized in other body tissues for the purpose of supporting organ regeneration.

“The hair follicle is like a mini-dispensable organ,” says Elaine Fuchs, head of the Laboratory of Mammalian Cell Biology and Development. “Throughout our lifetime, each hair follicle undergoes cyclical bouts of growth, destruction and rest through an intrinsic stem cell population. It provides an excellent opportunity to investigate the molecular process of tissue regeneration and stem cell self-renewal.”

For a new round of hair growth to begin, stem cells in the hair follicle must receive a signal to divide. In response to this signal, the hair follicle regenerates first by growing downward through the skin’s middle layer, the dermis, and then producing the specialized cells that form the hair. After a period during which the hair grows longer, stem cells stop dividing, and the hair follicle gradually retracts again. There is then a period of rest and the cycle repeats.

via Stem Cells In Hair Follicles Point To General Model Of Organ Regeneration.

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