Rebuilding the brain’s circuitry Healthy neurons can integrate into diseased areas

Source: Harvard Medical School
Date: November 24, 2011

Summary:

Neuron transplants have repaired brain circuitry and substantially normalized function in mice with a brain disorder, an advance indicating that key areas of the mammalian brain are more reparable than was widely believed. Collaborators from Harvard University, Massachusetts General Hospital (MGH), Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School (HMS) transplanted normally functioning embryonic neurons at a carefully selected stage of their development into the hypothalamus of mice unable to respond to leptin, a hormone that regulates metabolism and controls body weight. These mutant mice usually become morbidly obese, but the neuron transplants repaired defective brain circuits, enabling them to respond to leptin and thus experience substantially less weight gain.

Repair at the cellular-level of the hypothalamus — a critical and complex region of the brain that regulates phenomena such as hunger, metabolism, body temperature, and basic behaviors such as sex and aggression — indicates the possibility of new therapeutic approaches to even higher-level conditions such as spinal cord injury, autism, epilepsy, ALS (Lou Gehrig’s disease), Parkinson’s disease, and Huntington’s disease.


The findings are to appear Nov. 25 in Science.

Lab Creates Cells Used by Brain to Control Muscle Cells

Source: University of Central Florida
Date: November 22, 2011

Summary:

University of Central Florida researchers, for the first time, have used stem cells to grow neuromuscular junctions between human muscle cells and human spinal cord cells, the key connectors used by the brain to communicate and control muscles in the body. The success at UCF is a critical step in developing “human-on-a-chip” systems. The systems are models that recreate how organs or a series of organs function in the body. Their use could accelerate medical research and drug testing, potentially delivering life-saving breakthroughs much more quickly than the typical 10-year trajectory most drugs take now to get through animal and patient trials. The work, funded through the National Institute of Neurological Disorders and Stroke (NINDS) at the National Institutes of Health, is described in the December issue of Biomaterials.

Researchers uncover mechanism that regulates human pluripotent stem cell metabolism

Source: University of California - Los Angeles Health Sciences
Date: November 15, 2011

Summary:

Human pluripotent stem cells, which can develop into any cell type in the body, rely heavily on glycolysis, or sugar fermentation, to drive their metabolic activities. In contrast, mature cells in children and adults depend more on cell mitochondria to convert sugar and oxygen into carbon dioxide and water during a high energy-producing process called oxidative phosphorylation for their metabolic needs.

How cells progress from one form of energy production to another during development is unknown, although a finding by University of California Los Angeles stem cell researchers provides new insight for this transition that may have implications for using these cells for therapies in the clinic.

Based mostly on visual appearance, it had been assumed that pluripotent stem cells contained undeveloped and inactive mitochondria, which are the energy-producing power plants that drive most cell functions. It was thought that stem cell mitochondria could not respire, or convert sugar and oxygen into carbon dioxide and water with the production of energy. This led most scientists to expect that mitochondria matured and gained the ability to respire during the transition from pluripotent stem cells into differentiated body cells over time.

Surprisingly, UCLA stem cell researchers discovered that pluripotent stem cell mitochondria respire at roughly the same level as differentiated body cells, although they produced very little energy, thereby uncoupling the consumption of sugar and oxygen from energy generation. Rather than finding that mitochondria matured with cell differentiation, as was anticipated, the researchers uncovered a mechanism by which the stem cells converted from glucose fermentation to oxygen-dependent respiration to achieve full differentiation potential.

The four-year study appears in the Nov. 15, 2011 issue of The EMBO Journal, a peer-reviewed journal of the European Molecular Biology Organization.

Human Taste Cells Regenerate in a Dish

Source: Monell Chemical Senses Center
Date: April 6, 2011

Summary:

Following years of futile attempts, new research from the Monell Center demonstrates that living human taste cells can be maintained in culture for at least seven months. The findings provide scientists with a valuable tool to learn about the human sense of taste and how it functions in health and disease. This advance ultimately will assist efforts to prevent and treat taste loss or impairment due to infection, radiation, chemotherapy and chemical exposures.

To dispel the long-held belief, the Monell scientists first demonstrated in 2006 that taste cells from rats could successfully be maintained in culture. In the current study, published online in the journal Chemical Senses, they then applied that methodology to a more clinically relevant population -- humans. Taking tiny samples of tongue tissue from human volunteers, the researchers first adapted existing techniques to demonstrate that the human taste cells indeed can regenerate in culture. They went on to show that the new taste cells were functional, maintaining key molecular and physiological properties characteristic of the parent cells. For example, the new cells also were activated by sweet and bitter taste molecules.