Showing posts with label muscle growth. Show all posts
Showing posts with label muscle growth. Show all posts

Sunday, August 05, 2012

Heart muscle cell grafts suppress arrhythmias after heart attacks in animal study Transplanted heart cells

Source: University of Washington
Date: August 5, 2012

Summary:

Researchers have made a major advance in efforts to regenerate damaged hearts. They discovered that transplanted heart muscle cells, grown from stem cells, electrically couple and beat in sync with the heart’s own muscle. The grafts also reduced the incidence of arrhythmias (irregular heart rhythms) in a guinea pig model of myocardial infarction (commonly known as a heart attack). This finding from University of Washington-led research is reported in the Aug. 5 issue of Nature.

Thursday, August 02, 2012

Embryonic Blood Vessels That Make Blood Stem Cells Can Also Make Beating Heart Muscles

Source: University of California - Los Angeles Health Sciences
Date: August 2, 2012

Summary:

UCLA stem cell researchers have found for the first time a surprising and unexpected plasticity in the embryonic endothelium, the place where blood stem cells are made in early development. Scientists found that the lack of one transcription factor, a type of gene that controls cell fate by regulating other genes, allows the precursors that normally generate blood stem and progenitor cells in blood forming tissues to become something very unexpected -- beating cardiomyocytes, or heart muscle cells.

The finding is important because it suggests that the endothelium can serve as a source of heart muscle cells. The finding may provide new understanding of how to make cardiac stem cells for use in regenerative medicine. The two-year study is published Aug. 3, 2012 in the peer-reviewed journal Cell.

Monday, July 16, 2012

Lab-Engineered Muscle Implants Restore Function in Animal Studies

Source: Wake Forest Baptist Medical Center
Date: July 16, 2012

Summary:

WINSTON-SALEM, N.C. -- New research shows that exercise is a key step in building a muscle-like implant in the lab with the potential to repair muscle damage from injury or disease. In mice, these implants successfully prompt the regeneration and repair of damaged or lost muscle tissue, resulting in significant functional improvement.

In the current issue of Tissue Engineering Part A, scientists at Wake Forest Baptist Medical Center build on their prior work and report their second round of experiments showing that placing cells derived from muscle tissue on a strip of biocompatible material - and then "exercising" the strip in the lab - results in a muscle-like implant that can prompt muscle regeneration and significant functional recovery. The researchers hope the treatment can one day help patients with muscle defects ranging from cleft lip and palate to those caused by traumatic injuries or surgery.

For the study, small samples of muscle tissue from rats and mice were processed to extract cells, which were then multiplied in the lab. The cells, at a rate of 1 million per square centimeter, were placed onto strips of a natural biological material. The material, derived from pig bladder with all cells removed, is known to be compatible with the body.

Next, the strips were placed in a computer-controlled device that slowly expands and contracts - essentially "educating" the implants on how to perform in the body. This cyclic stretching and relaxation occurred three times per minute for the first five minutes of each hour for about a week. In the current study, the scientists tried several different protocols, such as adding more cells to the strips during the exercise process.

The next step was implanting the strips in mice with about half of a large muscle in the back (latissimus dorsi) removed to create functional impairment. While the strips are "muscle-like" at the time of implantation, they are not yet functional. Implantation in the body - sometimes referred to as "nature's incubator" - prompts further development.

The goal of the project was to speed up the body's natural recovery process as well as prompt the development of new muscle tissue. The scientists compared four groups of mice. One group received no surgical repair. The other groups received implants prepared in one of three ways: one was not exercised before implantation, one was exercised for five to seven days, and one had extra cells added midway through the exercise process. The results showed that exercising the implants made a significant difference in both muscle development and function.

Thursday, June 28, 2012

Successful Transplant of Patient-Derived Stem Cells Into Mice With Muscular Dystrophy

Source: University College London
Date: 28 June 2012

Summary:

Stem cells from patients with a rare form of muscular dystrophy have been successfully transplanted into mice affected by the same form of dystrophy, according to a new study published today in Science Translational Medicine.

For the first time, scientists have turned muscular dystrophy patients’ fibroblast cells (common cells found in connective tissue) into stem cells and then differentiated them into muscle precursor cells. The muscle cells were then genetically modified and transplanted into mice. The new technique could be used in the future for treating patients with limb-girdle muscular dystrophy (a rare form in which the shoulders and hips are primarily affected) and, possibly, other forms of muscular dystrophies.

In this study, scientists focused on genetically modifying a type of cell called a mesoangioblast, which is derived from blood vessels and has been shown in previous studies to have potential in treating muscular dystrophy. However, the authors found that they could not get a sufficient number of mesoangioblasts from patients with limb-girdle muscular dystrophy because the muscles of the patients were depleted of these cells.

Instead, scientists in this study “reprogrammed” adult cells from patients with limb-girdle muscular dystrophy into stem cells and were able to induce them to differentiate into mesoangioblast-like cells. After these ‘progenitor’ cells were genetically corrected using a viral vector, they were injected into mice with muscular dystrophy, where they homed-in on damaged muscle fibres.

The researchers also showed that when the same muscle progenitor cells were derived from mice the transplanted cells strengthened damaged muscle and enabled the dystrophic mice to run for longer on a treadmill than dystrophic mice that did not receive the cells.

Tuesday, June 19, 2012

New Method Generates Cardiac Muscle Patches from Stem Cells

Source: University of Michigan Health System
Date: June 19, 2012

Summary:

A cutting-edge method developed at the University of Michigan Center for Arrhythmia Research successfully uses stem cells to create heart cells capable of mimicking the heart's crucial squeezing action. The cells displayed activity similar to most people's resting heart rate. At 60 beats per minute, the rhythmic electrical impulse transmission of the engineered cells in the U-M study is 10 times faster than in most other reported stem cell studies.

An image of the electrically stimulated cardiac cells is displayed on the cover of the current issue of Circulation Research, a publication of the American Heart Association. For those suffering from common, but deadly heart diseases, stem cell biology represents a new medical frontier. The U-M team of researchers is using stem cells in hopes of helping the 2.5 million people with an arrhythmia, an irregularity in the heart's electrical impulses that can impair the heart's ability to pump blood.

Their objective included developing a bioengineering approach, using stem cells generated from skin biopsies, which can be used to create large numbers of cardiac muscle cells that can transmit uniform electrical impulses and function as a unit. Furthermore, the team designed a fluorescent imaging platform using light emitting diode (LED) illumination to measure the electrical activity of the cells.

Monday, May 28, 2012

New Stem Cell Technique Promises Abundance of Key Heart Cells

Source: University of Wisconsin-Madison
Date: May 28, 2012

Summary:

A team of scientists at the University of Wisconsin-Madison describes a way to transform human stem cells -- both embryonic and induced pluripotent stem cells -- into the critical heart muscle cells by simple manipulation of one key developmental pathway. The technique promises a uniform, inexpensive and far more efficient alternative to the complex bath of serum or growth factors now used to nudge blank slate stem cells to become specialized heart cells. in the Proceedings of the National Academy of Sciences.

The capacity to make the heart cells using induced pluripotent stem cells, which can come from adult patients with diseased hearts, means scientists will be able to more readily model those diseases in the laboratory. Such cells contain the genetic profile of the patient, and so can be used to recreate the disease in the lab dish for study. Cardiomyocytes are difficult or impossible to obtain directly from the hearts of patients and, when obtained, survive only briefly in the lab. Scientists also have high hopes that one day healthy lab-grown heart cells can be used to replace the cardiomyocytes that die as a result of heart disease, the leading cause of death in the United States.

Wednesday, February 15, 2012

Stem Cell Study in Mice Offers Hope for Treating Heart Attack Patients

Source: University of California - San Francisco
Date: February 15, 2012

Summary:

A UCSF stem cell study conducted in mice suggests a novel strategy for treating damaged cardiac tissue in patients following a heart attack. The approach potentially could improve cardiac function, minimize scar size, lead to the development of new blood vessels -- and avoid the risk of tissue rejection. In the investigation, reported online in the journal PLoS ONE, the researchers isolated and characterized a novel type of cardiac stem cell from the heart tissue of middle-aged mice following a heart attack. Then, in one experiment, they placed the cells in the culture dish and showed they had the ability to differentiate into cardiomyocytes, or "beating heart cells," as well as endothelial cells and smooth muscle cells, all of which make up the heart. In another, they made copies, or "clones," of the cells and engrafted them in the tissue of other mice of the same genetic background who also had experienced heart attacks. The cells induced angiogenesis, or blood vessel growth, or differentiated, or specialized, into endothelial and smooth muscle cells, improving cardiac function.

Tuesday, November 29, 2011

Body Rebuilding: Researchers Regenerate Muscle Tissue in Mice

Source: Worcester Polytechnic Institute
Date: November 29, 2011

Summary:

A team of scientists from Worcester Polytechnic Institute (WPI) and CellThera, a private company located in WPI's Life Sciences and Bioengineering Center, have regenerated functional muscle tissue in mice, opening the door for a new clinical therapy to treat people who suffer major muscle trauma. The team used a novel protocol to coax mature human muscle cells into a stem cell-like state and grew those reprogrammed cells on biopolymer microthreads. The threads were placed in a wound created by surgically removing a large section of leg muscle from a mouse. Over time, the threads and cells restored near-normal function to the muscle published in the current issue of the journal Tissue Engineering. Surprisingly, the microthreads, which were used simply as a scaffold to support the reprogrammed human cells, actually seemed to accelerate the regeneration process by recruiting progenitor mouse muscle cells, suggesting that they alone could become a therapeutic tool for treating major muscle trauma.

Wednesday, December 01, 2010

A Fountain of Youth in Your Muscles

Source: American Friends of Tel Aviv University
Date: December 1, 2010

Summary:

New research from Tel Aviv University has found that "endurance exercises," like a Central Park jog or a spinning class, can make us look younger. The key, exercise, unlocks the stem cells of our muscles. Prof. Dafna Benayahu and her team at Tel Aviv University's Sackler School of Medicine say their findings explain for the first time why older people who have exercised throughout their lives age more gracefully. They have discovered how endurance exercise increases the number of muscle stem cells and enhances their ability to rejuvenate old muscles. The researchers hope their finding can lead to a new drug to help the elderly and immobilized heal their muscles faster. The results of the study were recently published in the journal PLoS ONE.

Tuesday, September 28, 2010

Sodium Plays Key Role in Tissue Regeneration

Source: Tufts University
Date: September 28, 2010

Summary:

Sodium gets a bad rap for contributing to hypertension and cardiovascular disease. Now biologists at Tufts University's School of Arts and Sciences have discovered that sodium also plays a key role in initiating a regenerative response after severe injury. The Tufts scientists have found a way to regenerate injured spinal cord and muscle by using small molecule drugs to trigger an influx of sodium ions into injured cells.

The approach breaks new ground in the field of biomedicine because it requires no gene therapy; can be administered after an injury has occurred and even after the wound has healed over; and is bioelectric, rather than chemically based. In a paper appearing as the cover story of the September 29, 2010, issue of the Journal of Neuroscience, the Tufts team reported that a localized increase in sodium ions was necessary for young Xenopus laevis tadpoles to regenerate their tails – complex appendages containing spinal cord, muscle and other tissue.

Thursday, August 05, 2010

Two New Paths to the Dream: Regeneration

Source: New York Times
Date: August 5, 2010

Summary:

The New York Times reported a story on the discovery of new approaches to regenerating limbs using the body's own cells. The first, an announcement by researchers at Stanford University School of Medicine, the ability of newts to regenerate tissue was successfully replicated in mice:

Two research reports published Friday offer novel approaches to the age-old dream of regenerating the body from its own cells. Animals like newts and zebra fish can regenerate limbs, fins, even part of the heart. If only people could do the same, amputees might grow new limbs and stricken hearts be coaxed to repair themselves.

...In the first of the two new approaches, a research group at Stanford University led by Helen M. Blau, Jason H. Pomerantz and Kostandin V. Pajcini has taken a possible first step toward unlocking the human ability to regenerate. By inactivating two genes that work to suppress tumors, they got mouse muscle cells to revert to a younger state, start dividing and help repair tissue.


In a second experiment, a different technique to regenerating a tissue was announced by researchers at the University of California, San Francisco to regenerate heart tissue by reprogramming heart tissue cells into heart muscle cells reported in the journal Cell:

A second, quite different approach to regenerating a tissue is reported in Friday’s issue of Cell by Deepak Srivastava and colleagues at the University of California, San Francisco. Working also in the mouse, they have developed a way of reprogramming the ordinary tissue cells of the heart into heart muscle cells, the type that is irretrievably lost in a heart attack.
The Japanese scientist Shinya Yamanaka showed three years ago that skin cells could be converted to embryonic stem cells simply by adding four proteins known to regulate genes. Inspired by Dr. Yamanaka’s method, Dr. Srivastava and his colleagues selected 14 such proteins and eventually found that with only three of them they could convert heart fibroblast cells into heart muscle cells.

Wednesday, August 04, 2010

Newts' Ability to Regenerate Tissue Replicated in Mouse Cells

Source: Stanford University
Date: August 4, 2010

Summary:

New research suggests a reason why mammals are unable to re-grow a limb or produce new heart muscle cells: Restricting cells' ability to pop in and out of the cell cycle at will -- a prerequisite for the cell division necessary to make new tissue -- reduces the chances that they'll run amok and form potentially deadly cancers.

Scientists at the Stanford University School of Medicine have taken a big step toward being able to confer this regenerative capacity on mammalian muscle cells; they accomplished this feat in experiments with laboratory mice in which they blocked the expression of just two tumor-suppressing proteins. The finding may move us closer to future regenerative therapies in humans -- surprisingly, by sending us shimmying back down the evolutionary tree. The research will be published in Cell Stem Cell.


Wired magazine published a news story based on this news release.

Monday, February 15, 2010

New study suggests stem cells sabotage their own DNA to produce new tissues

Source: Ottawa Hospital Research Institute
Date: February 15, 2010

Summary:

A new study from the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa suggests that stem cells intentionally break their own DNA as a way of regulating tissue development. The study, published in Proceedings of the National Academy of Sciences (PNAS), could dramatically change how researchers think about tissue development, stem cells and cancer.

The discovery has important implications for a number of areas. It could help researchers develop better ways to activate stem cells, so that they can produce new tissues for therapeutic purposes. It also suggests that DNA mutations, which can contribute to a variety of diseases, may initially occur as a result of a normal cellular process. And it has implications for researchers developing therapies that inhibit programmed cell death, suggesting that such therapies may also inhibit normal tissue development.

Thursday, October 01, 2009

Scientists discover clues to what makes human muscle age

Source: University of California - Berkeley
Date: September 30, 2009

Summary:

A study led by researchers at the University of California, Berkeley, has identified critical biochemical pathways linked to the aging of human muscle. By manipulating these pathways, the researchers were able to turn back the clock on old human muscle, restoring its ability to repair and rebuild itself. The findings will be reported in the Sept. 30 issue of the journal EMBO Molecular Medicine, a peer-reviewed, scientific publication of the European Molecular Biology Organization.

Wednesday, September 30, 2009

Clues To Reversing Aging Of Human Muscle Discovered

Source: University of California - Berkeley
Date: September 30, 2009

Summary:

A study led by researchers at the University of California, Berkeley, has identified critical biochemical pathways linked to the aging of human muscle. By manipulating these pathways, the researchers were able to turn back the clock on old human muscle, restoring its ability to repair and rebuild itself. The findings will be reported in the Sept. 30 issue of the journal EMBO Molecular Medicine, a peer-reviewed, scientific publication of the European Molecular Biology Organization.

Monday, August 03, 2009

Researchers Demonstrate How Stem Cell Line Regenerates New Cardiac Cells

Source: University of Miami Miller School of Medicine
Date: August 3, 2009

Summary:

As the field of stem cell based therapies has progressed, there have been numerous questions about the exact way one of the most promising lines of adult stem cells works to repair damaged heart muscle. Although cells obtained from adult bone marrow are proving to be useful to treat heart disease, there has been a major controversy over whether they are true stem cells capable of forming new heart muscle.

Cardiologists at the University of Miami Miller School of Medicine have definitively shown that mesenchymal stem cells from bone marrow do in fact form new heart muscle and blood vessels, leading to major degrees of tissue repair in hearts damaged by a heart attack. Their findings have been published in the August 3 issue of the Proceedings of the National Academy of Sciences.

Thursday, June 04, 2009

Ottawa scientists discover new way to enhance stem cells to stimulate muscle regeneration

Source: Ottawa Hospital Research Institute
Date: June 4, 2009

Summary:

Scientists at the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa have discovered a powerful new way to stimulate muscle regeneration, paving the way for new treatments for debilitating conditions such as muscular dystrophy. The research, to be published in the June 5 issue of Cell Stem Cell, shows for the first time that a protein called Wnt7a increases the number of stem cells in muscle tissue, leading to accelerated growth and repair of skeletal muscle.

Thursday, January 08, 2009

Embryonic Heart Cells Thrive Only In An Environment That's Just Right

Source: University of Pennsylvania
Date: January 7, 2009

Summary:

Cellular engineers at the University of Pennsylvania have determined that cardiomyocytes, the specialized cells that form the heart muscle, thrive when cultured in an environment that mimics their own elastic nature but falter, weaken or die when “grown” on stiffer or softer materials. The study’s methods and analyses demonstrate that individual heart cells, similar in character to those derived from embryonic stem cells and induced pluripotent stem cells, are affected by physical forces at the cellular level and require the proper myocardial environment to grow and potentially repair damaged heart muscle, a key goal of stem cell and cardiovascular research. It also highlights the need for stem cell science to focus on physical parameters such as fibrosis as well as the mechanics of microenvironments to optimize cell therapy and new muscle growth.

Sunday, December 14, 2008

Single adult stem cell can self renew, repair tissue damage in live mammal

Source: Source: American Society for Cell Biology
Date: December 14, 2008

Summary:

The first demonstration that a single adult stem cell can self-renew in a mammal was reported at the American Society for Cell Biology (ASCB) 48th Annual Meeting, Dec. 13-17, 2008 in San Francisco. The transplanted adult stem cell and its differentiated descendants restored lost function to mice with hind limb muscle tissue damage.

Tuesday, November 25, 2008

Scientists achieve repair of injured heart muscle in lab tests of stem cells

Source: Children's Hospital of Pittsburgh
Date: November 25, 2008

Summary:

Researchers at Children's Hospital of Pittsburgh of UPMC have been able to effectively repair damaged heart muscle in an animal model using a novel population of stem cells they discovered that is derived from human skeletal muscle tissue. The research team — led by Johnny Huard, PhD — transplanted stem cells purified from human muscle-derived blood vessels into the hearts of mice that had heart damage similar to that which would occur in people who had suffered a heart attack. The transplanted myoendothelial cells repaired the injured muscle, stimulated the growth of new blood vessels in the heart and reduced scar tissue from the injury, thereby dramatically improving the function of the injured left ventricle. Results of this study are published in the Dec. 2 issue of the Journal of the American College of Cardiology.