Sleep disorder could be a sign of Parkinson's and Alzheimer's

Research shows that a brain disorder that causes people to act out their dreams may be a sign of Parkinson's or Alzheimer's.

A sleep disorder that causes people to act out their dreams is a predictor of brain diseases like Alzheimer's and Parkinson's, a new research has found. 

"Rapid-eye-movement sleep behaviour disorder (RBD) is not just a precursor but also a critical warning sign of neurodegeneration that can lead to brain disease," said associate professor and lead author Dr John Peever from the University of Toronto in Canada. 

"In fact, as many as 80 to 90 per cent of people with RBD will develop a brain disease," said Peever. 

The disturbance occurs during the rapid-eye-movement (REM) stage of sleep and causes people to act out their dreams, often resulting in injury to themselves and/or bed partner, researchers said. 

In healthy brains, muscles are temporarily paralysed during sleep to prevent this from happening. 

"It's important for clinicians to recognise RBD as a potential indication of brain disease in order to diagnose patients at an earlier stage," said Peever. 

"This is important because drugs that reduce neurodegeneration could be used in RBD patients to prevent (or protect) them from developing more severe degenerative disorders," Peever said. 

His research examines the idea that neurodegeneration might first affect areas of the brain that control sleep before attacking brain areas that cause more common brain diseases like Alzheimer's. 

Peever said he hopes the results of his study lead to earlier and more effective treatment of neurodegenerative diseases. 

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New brain disorder discovered caused by genetic mutation

A new genetic brain disorder was found by two independent research teams. This disorder is characterized by sensory and motor defects, as well as reduced brain size.

A newly identified genetic disorder associated with degeneration of the central and peripheral nervous systems in humans, along with the genetic cause, is reported in the April 24, 2014 issue ofCell.

The findings were generated by two independent but collaborative scientific teams, one based primarily at Baylor College of Medicine and the Austrian Academy of Sciences, the other at the University of California, San Diego School of Medicine, the Academic Medical Center (AMC) in the Netherlands and the Yale University School of Medicine.

By performing DNA sequencing of more than 4,000 families affected by neurological problems, the two research teams independently discovered that a disease marked by reduced brain size and sensory and motor defects is caused by a mutation in a gene called CLP1, which is known to regulate tRNA metabolism in cells. Insights into this rare disorder, the researchers said, may have important implications for the future treatment of more common neurological conditions.

"What we found particularly striking, when considering the two studies together, is that this is not a condition that we would have been able to separate from other similar disorders based purely on patient symptoms or clinical features," said Joseph G. Gleeson, MD, Howard Hughes Medical Institute investigator, professor in the UC San Diego departments of Neurosciences and Pediatrics and at Rady Children's Hospital-San Diego, a research affiliate of UC San Diego. "Once we had the gene spotted in these total of seven families, then we could see the common features. It is the opposite way that doctors have defined diseases, but represents a transformation in the way that medicine is practiced."

Each child tested was affected by undiagnosed neurological problems. All of the children were discovered to carry a mutation in the CLP1 gene and displayed the same symptoms, such as brain malformations, intellectual disabilities, seizures and sensory and motor defects. A similar pattern emerged in both studies, one led by Gleeson, with Murat Gunel, MD, of the Yale University School of Medicine and Frank Baas, PhD, of the Academic Medical Center in the Netherlands, and the other by Josef Penninger and Javier Martinez of the Austrian Academy of Sciences, teamed with James R. Lupski, MD, PhD, of the Baylor College of Medicine.

"Knowing fundamental pathways that regulate the degeneration of neurons should allow us to define new pathways that, when modulated, might help us to protect motor neurons from dying, such as in Lou Gehrig's disease," said Penninger, scientific director of the Institute of Molecular Biotechnology of the Austrian Academy of Sciences.

The CLP1 protein plays an important role in generating mature, functional molecules called transfer RNAs (tRNAs), which shuttle amino acids to cellular subunits called ribosomes for assembly into proteins. Mutations affecting molecules involved in producing tRNAs have been implicated in human neurological disorders, such as pontocerebellar hypoplasia (PCH), a currently incurable neurodegenerative disease affecting children. Although CLP1 mutations have been linked to neuronal death and motor defects in mice, the role of CLP1 in human disease was not known until now.

These scientists performed DNA sequencing on children with neurological problems. Seven out of the more than 4,000 families studied shared an identical CLP1 mutation, which was associated with motor defects, speech impairments, seizures, brain atrophy and neuronal death.

Bass at the AMC said the neurological condition represents a new form of PCH. "Identification of yet another genetic cause for this neurodegenerative disorder will allow for better genetic testing and counseling to families with an affected child," he said.

In a published paper last year, Gleeson and colleagues identified a different gene mutation for a particularly severe form of PCH, and reported early evidence that a nutritional supplement might one day be able to prevent or reverse the condition.

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Scientists grow mini human brains

Scientists found a way to grow mini three-dimensional human brains in a lab. This will help in the discovery of brain development and how different disorders may develop.

Complex human brain tissue has been successfully developed in a three-dimensional culture system established in an Austrian laboratory. The method described in the current issue of Natureallows pluripotent stem cells to develop into cerebral organoids -- or "mini brains" -- that consist of several discrete brain regions.

Instead of using so-called patterning growth factors to achieve this, scientists at the Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences (OeAW) fine-tuned growth conditions and provided a conducive environment. As a result, intrinsic cues from the stem cells guided the development towards different interdependent brain tissues. Using the "mini brains," the scientists were also able to model the development of a human neuronal disorder and identify its origin -- opening up routes to long hoped-for model systems of the human brain.

The development of the human brain remains one of the greatest mysteries in biology. Derived from a simple tissue, it develops into the most complex natural structure known to man. Studies of the human brain's development and associated human disorders are extremely difficult, as no scientist has thus far successfully established a three-dimensional culture model of the developing brain as a whole. Now, a research group lead by Dr. Jürgen Knoblich at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA) has just changed that.

Brain Size Matters

Starting with established human embryonic stem cell lines and induced pluripotent stem (iPS) cells, the group identified growth conditions that aided the differentiation of the stem cells into several brain tissues. While using media for neuronal induction and differentiation, the group was able to avoid the use of patterning growth factor conditions, which are usually applied in order to generate specific cell identities from stem cells. Dr. Knoblich explains the new method: "We modified an established approach to generate so-called neuroectoderm, a cell layer from which the nervous system derives. Fragments of this tissue were then maintained in a 3D-culture and embedded in droplets of a specific gel that provided a scaffold for complex tissue growth. In order to enhance nutrient absorption, we later transferred the gel droplets to a spinning bioreactor. Within three to four weeks defined brain regions were formed."

After only 15 -- 20 days, so-called "cerebral organoids" formed which consisted of continuous tissue (neuroepithelia) surrounding a fluid-filled cavity that was reminiscent of a cerebral ventricle. After 20 -- 30 days, defined brain regions, including a cerebral cortex, retina, meninges as well as choroid plexus, developed. After two months, the mini brains reached a maximum size, but they could survive indefinitely (currently up to 10 months) in the spinning bioreactor. Further growth, however, was not achieved, most likely due to the lack of a circulation system and hence a lack of nutrients and oxygen at the core of the mini brains.

Microcephaly in Mini Brains

The new method also offers great potential for establishing model systems for human brain disorders. Such models are urgently needed, as the commonly used animal models are of considerably lower complexity, and often do not adequately recapitulate the human disease.

Knoblich's group has now demonstrated that the mini brains offer great potential as a human model system by analysing the onset of microcephaly, a human genetic disorder in which brain size is significantly reduced. By generating iPS cells from skin tissue of a microcephaly patient, the scientists were able to grow mini brains affected by this disorder. As expected, the patient derived organoids grew to a lesser size.

Further analysis led to a surprising finding: while the neuroepithilial tissue was smaller than in mini brains unaffected by the disorder, increased neuronal outgrowth could be observed. This lead to the hypothesis that, during brain development of patients with microcephaly, the neural differentiation happens prematurely at the expense of stem and progenitor cells which would otherwise contribute to a more pronounced growth in brain size. Further experiments also revealed that a change in the direction in which the stem cells divide might be causal for the disorder.

"In addition to the potential for new insights into the development of human brain disorders, mini brains will also be of great interest to the pharmaceutical and chemical industry," explains Dr. Madeline A. Lancaster, team member and first author of the publication. "They allow for the testing of therapies against brain defects and other neuronal disorders. Furthermore, they will enable the analysis of the effects that specific chemicals have on brain development."

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