Posts tagged disease

July 23, 2012 By David Orenstein

(Medical Xpress) — This week the Journal of the American Medical Association published a study with unfortuate news for the millions of people who suffer from multiple sclerosis. In the large study, a therapy known as interferon beta failed to stave off the progression of the incurable disease. Albert Lo, associate professor of neurology and epidemiology, comments on what the study means for patients, why it was well-designed, and how a new effort to support research on the disease in Rhode Island could help.

The results of this study with nearly 2,700 participants showed that treatment with interferon beta, which is a major class of disease-modifying therapy for multiple sclerosis, did not prevent progression of disability, which is very disappointing from a therapeutic perspective. Currently, there is no cure for MS, and as a lifelong disorder of the nervous system, MS is characterized by episodic relapses of neurological injury such as weakness or blindness. While in most cases, there is a varying degree of recovery after relapses, over time, disability accumulates. The accumulation of deficits and the loss of physical and mental function is a major concern for people with MS and their clinicians.

Currently, there is no medication on the market that is directed explicitly for neuroprotection and the prevention of disability. Many had hoped that the interferons, along with the other disease-modifying agents (which were developed to reduce relapse rates) would also have a significant effect on protecting patients from MS disability.

Although the results from this study were not as we would have hoped, they reflect a marked improvement over prior studies which used known methodologic flaws. The new results from the Tremlett group point to the importance of the research methodology used (prospectively collected longitudinal study data) and a well-controlled design to generate the results – approaches that we are using in our own research at Brown University.

A number of the early studies examining the effect of interferons on disability primarily used patient sample groups of convenience for post-marketing studies. They indicated that interferons were in fact preventing disability. However, using samples of convenience inherently includes a number of biases and problems. Dr. Tremlett’s results were generated from a more systematic longitudinal study in which biases and shortcomings can be better addressed. Therefore, making conclusions and clinical decisions from the results is more reliable. These data both will help in making clinical decisions on treating MS patients during the later course of their disease, when there are virtually no relapses, and will help to point more urgently toward the clinical need of an agent to prevent disability.

Provided by Brown University

Source: medicalxpress.com

ScienceDaily (July 19, 2012) — While clinical trial results are being released regarding drugs intended to decrease amyloid production — thought to contribute to decline in Alzheimer’s disease — clinical trials of drugs targeting other disease proteins, such as tau, are in their initial phases.

Penn Medicine research presented July 19 at the 2012 Alzheimer’s Association International Conference (AAIC) shows that an anti-tau treatment called epithilone D (EpoD) was effective in preventing and intervening the progress of Alzheimer’s disease in animal models, improving neuron function and cognition, as well as decreasing tau pathology.

By targeting tau, the drug aims to stabilize microtubules, which help support and transport of essential nutrients and information between cells. When tau malfunctions, microtubules break and tau accumulates into tangles.

"This drug effectively hits a tau target by correcting tau loss of function, thereby stabilizing microtubules and offsetting the loss of tau due to its formation into neurofibrillary tangles in animal models, which suggests that this could be an important option to mediate tau function in Alzheimer’s and other tau-based neurodegenerative diseases," said John Trojanowski, MD, PhD, professor of Pathology and Laboratory Medicine in the Perelman School of Medicine at the University of Pennsylvania. "In addition to drugs targeting amyloid, which may not work in advanced Alzheimer’s disease, our hope is that this and other anti-tau drugs can be tested in people with Alzheimer’s disease to determine whether stabilizing microtubules damaged by malfunctioning tau protein may improve clinical and pathological outcomes."

The drug, identified through Penn’s Center for Neurodegenerative Disease Research (CNDR) Drug Discovery Program, was previously shown to prevent further neurological damage and improve cognitive performance in animal models*. The Penn research team includes senior investigator Bin Zhang, MD, and Kurt Brunden, PhD, director of Drug Discovery at CNDR.

Bristol-Myers Squibb, who developed and owns the rights to the drug, has started enrolling patients into a phase I clinical trial in people with mild Alzheimer’s disease.

Source: Science Daily

ScienceDaily (July 18, 2012) — Researchers at Oregon Health & Science University School of Dentistry have discovered that TDP-43, a protein strongly linked to ALS (amyotrophic lateral sclerosis) and other neurodegenerative diseases, appears to activate a variety of different molecular pathways when genetically manipulated. The findings have implications for understanding and possibly treating ALS and neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

ALS affects two in 100,000 adults in the United States annually and the prognosis for patients is grim.The new discovery is published online in G3: Genes, Genomes, Genetics (and the July 2012 print issue of G3).

Using a fruit fly model, the OHSU team genetically increased or eliminated TDP-43 to study its effect on the central nervous system. By using massively parallel sequencing methods to profile the expression of genes in the central nervous system, the team found that the loss of TDP-43 results in widespread gene activation and altered splicing, much of which is reversed by rescue of TDP-43 expression. Although previous studies have implicated both absence and over expression of TDP-43 in ALS, the OHSU study showed little overlap in the gene expression between these two manipulations, suggesting that the bulk of the genes affected are different.

"Our data suggest that TDP-43 plays a role in synaptic transmission, synaptic release and endocytosis," said Dennis Hazelett, Ph.D., lead author of the study. "We also uncovered a potential novel regulation of several pathways, many targets of which appear to be conserved."

Source: Science Daily

July 18, 2012

A new guideline released by the American Academy of Neurology recommends several treatments for people with Huntington’s disease who experience chorea—jerky, random, uncontrollable movements that can make everyday activities challenging. The guideline is published in the July 18, 2012, online issue of Neurology.

"Chorea can be disabling, worsen weight loss and increase the risk of falling," said guideline lead author Melissa Armstrong, MD, MSc, with the University of Maryland Department of Neurology and a member of the American Academy of Neurology.

Huntington’s disease is a complex disease with physical, cognitive and behavioral symptoms. The new guideline addresses only one aspect of the disease that may require treatment.

The guideline found that the drugs tetrabenazine (TBZ), riluzole and amantadine can be helpful and the drug nabilone may also be considered to treat chorea. The medications riluzole, amantadine and nabilone are not often prescribed for Huntington’s disease.

"People with Huntington’s disease who have chorea should discuss with their doctors whether treating chorea is a priority. Huntington’s disease is complex with a wide range of sometimes severe symptoms and treating other symptoms may be a higher priority than treating chorea," said Armstrong.

Armstrong adds that it is important for patients to understand that their doctors may try drugs not recommended in this guideline to treat chorea. More research is needed to know if drugs such as those used for psychosis are effective; however, doctors may prescribe them on the basis of past clinical experience.

Provided by American Academy of Neurology

Source: medicalxpress.com

July 18, 2012

(Phys.org) — New research at the Hebrew University of Jerusalem sheds light on pluripotency—the ability of embryonic stem cells to renew themselves indefinitely and to differentiate into all types of mature cells. Solving this problem, which is a major challenge in modern biology, could expedite the use of embryonic stem cells in cell therapy and regenerative medicine. If scientists can replicate the mechanisms that make pluripotency possible, they could create cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer’s, Parkinson’s, diabetes and other degenerative diseases.

To shed light on these processes, researchers in the lab of Dr. Eran Meshorer, in the Department of Genetics at the Hebrew University’s Alexander Silberman Institute of Life Sciences, are combining molecular, microscopic and genomic approaches. Meshorer’s team is focusing on epigenetic pathways—which cause biological changes without a corresponding change in the DNA sequence—that are specific to embryonic stem cells.

The molecular basis for epigenetic mechanisms is chromatin, which is comprised of a cell’s DNA and structural and regulatory proteins. In groundbreaking research performed by Shai Melcer, a PhD student in the Meshorer lab, the mechanisms which support an “open” chromatin conformation in embryonic stem cells were examined. The researchers found that chromatin is less condensed in embryonic stem cells, allowing them the flexibility or “functional plasticity” to turn into any kind of cell.

A distinct pattern of chemical modifications of chromatin structural proteins (referred to as the acetylation and methylation of histones) enables a looser chromatin configuration in embryonic stem cells. During the early stages of differentiation, this pattern changes to facilitate chromatin compaction.

But even more interestingly, the authors found that a nuclear lamina protein, lamin A, is also a part of the secret. In all differentiated cell types, lamin A binds compacted domains of chromatin and anchors them to the cell’s nuclear envelope. Lamin A is absent from embryonic stem cells and this may enable the freer, more dynamic chromatin state in the cell nucleus. The authors believe that chromatin plasticity is tantamount to functional plasticity since chromatin is made up of DNA that includes all genes and codes for all proteins in any living cell. Understanding the mechanisms that regulate chromatin function will enable intelligent manipulations of embryonic stem cells in the future.

"If we can apply this new understanding about the mechanisms that give embryonic stem cells their plasticity, then we can increase or decrease the dynamics of the proteins that bind DNA and thereby increase or decrease the cells’ differentiation potential," concludes Dr. Meshorer. “This could expedite the use of embryonic stem cells in cell therapy and regenerative medicine, by enabling the creation of cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer’s, Parkinson’s, diabetes and other degenerative diseases.”

Source: PHYS.ORG

July 16, 2012

For more than 20 years, doctors have been using cells from blood that remains in the placenta and umbilical cord after childbirth to treat a variety of illnesses, from cancer and immune disorders to blood and metabolic diseases.

This microscope image shows a colony of neurons derived from cord-blood cells using stem cell reprogramming technology. The green and red glow indicates that the cells are producing protein makers found in neurons, evidence that the cord-blood cells did in fact morph into neurons. The blue glow marks the nuclei of the neurons. Credit: Image: Courtesy of Alessandra Giorgetti

Now, scientists at the Salk Institute for Biological Studies have found a new way-using a single protein, known as a transcription factor-to convert cord blood (CB) cells into neuron-like cells that may prove valuable for the treatment of a wide range of neurological conditions, including stroke, traumatic brain injury and spinal cord injury.

The researchers demonstrated that these CB cells, which come from the mesoderm, the middle layer of embryonic germ cells, can be switched to ectodermal cells, outer layer cells from which brain, spinal and nerve cells arise. “This study shows for the first time the direct conversion of a pure population of human cord blood cells into cells of neuronal lineage by the forced expression of a single transcription factor,” says Juan Carlos Izpisua Belmonte, a professor in Salk’s Gene Expression Laboratory, who led the research team. The study, a collaboration with Fred H. Gage, a professor in Salk’s Laboratory of Genetics, and his team, was published on July 16 in the Proceedings of the National Academy of Sciences.

"Unlike previous studies, where multiple transcription factors were necessary to convert skin cells into neurons, our method requires only one transcription factor to convert CB cells into functional neurons," says Gage.

The Salk researchers used a retrovirus to introduce Sox2, a transcription factor that acts as a switch in neuronal development, into CB cells. After culturing them in the laboratory, they discovered colonies of cells expressing neuronal markers. Using a variety of tests, they determined that the new cells, called induced neuronal-like cells (iNC), could transmit electrical impulses, signaling that the cells were mature and functional neurons. Additionally, they transferred the Sox2-infused CB cells to a mouse brain and found that they integrated into the existing mouse neuronal network and were capable of transmitting electrical signals like mature functional neurons.

"We also show that the CB-derived neuronal cells can be expanded under certain conditions and still retain the ability to differentiate into more mature neurons both in the lab and in a mouse brain," says Mo Li, a scientist in Belmonte’s lab and a co-first author on the paper with Alessandra Giorgetti, of the Center for Regenerative Medicine, in Barcelona, and Carol Marchetto of Gage’s lab. "Although the cells we developed were not for a specific lineage-for example, motor neurons or mid-brain neurons-we hope to generate clinically relevant neuronal subtypes in the future."

Importantly, says Marchetto, “We could use these cells in the future for modeling neurological diseases such as autism, schizophrenia, Parkinson’s or Alzheimer’s disease.”

Cord blood cells, says Giorgetti, offer a number of advantages over other types of stem cells. First, they are not embryonic stem cells and thus they are not controversial. They are more plastic, or flexible, than adult stem cells from sources like bone marrow, which may make them easier to convert into specific cell lineages. The collection of CB cells is safe and painless and poses no risk to the donor, and they can be stored in blood banks for later use.

"If our protocol is developed into a clinical application, it could aid in future cell-replacement therapies," says Li. "You could search all the cord blood banks in the country to look for a suitable match."

Provided by Salk Institute

Source: medicalxpress.com

ScienceDaily (July 16, 2012) — Mayo Clinic researchers have found a novel way to monitor real-time chemical changes in the brains of patients undergoing deep brain stimulation (DBS). The groundbreaking insight will help physicians more effectively use DBS to treat brain disorders such as Parkinson’s disease, depression and Tourette syndrome.

The findings are published in the journal Mayo Clinic Proceedings.

Researchers hope to use the discovery to create a DBS system that can instantly respond to chemical changes in the brain. Parkinson’s, Tourette syndrome and depression all involve a surplus or deficiency of neurochemicals in the brain. The idea is to monitor those neurochemicals and adjust them to appropriate levels.

"We can learn what neurochemicals can be released by DBS, neurochemical stimulation, or other stimulation. We can basically learn how the brain works," says author Su-Youne Chang, Ph.D., of the Mayo Clinic Neurosurgery Department. As researchers better understand how the brain works, they can predict changes, and respond before those changes disrupt brain functioning.

Researchers observed the real-time changes of the neurotransmitter adenosine in the brains of tremor patients undergoing deep brain stimulation. Neurotransmitters such as dopamine and serotonin are chemicals that transmit signals from a neuron to a target cell across a synapse.

The team used fast scan cyclic voltammetry (FSCV) to quantify concentrations of adenosine released in patients during deep brain stimulation. The data was recorded using Wireless Instantaneous Neurotransmitter Concentration Sensing, a small wireless neurochemical sensor implanted in the patient’s brain. The sensor, combined with FSCV, scans for the neurotransmitter and translates that information onto a laptop in the operating room. The sensor has previously identified neurotransmitters serotonin and dopamine in tests in brain tissue. This was the first time researchers used this technique in patients.

Tremors are a visual cue that the technique is working; researchers suspect adenosine plays a role in reducing tremors.

Researchers also hope to learn more about conditions without such external manifestations.

"We can’t watch pain as we do tremors," says Kendall Lee, M.D., Ph.D., a Mayo Clinic neurosurgeon. "What is exciting about this electrochemical feedback is that we can monitor the brain without external feedback. So now, we can monitor neurochemicals in the brain and learn about brain processes like pain."

DBS has been used successfully worldwide to treat patients with tremors. However, physicians do not fully understand why DBS works in patients. They know that when DBS electrodes are inserted before electrical stimulation, there is an immediate tremor reduction. Known as the microthalamotomy effect, it is reported in up to 53 percent of patients and known to last as long as a year.

Researchers hope to use the study findings to create a self-contained “smart” DBS system.

"With the stimulator and detection, we can create algorithms and then raise neurotransmitters to a specified level," says Kevin Bennet, a Mayo Clinic engineer who helped create the system. "We can raise these chemicals to appropriate levels, rising and falling with each person throughout their life. Within milliseconds, we can measure, calculate and respond. From the patient’s perspective, this would be essentially instantaneous."

Source: Science Daily