The amyloid cascade hypothesis of Alzheimer’s disease (AD) posits that sticky aggregations or plaques of amyloid-beta peptides accumulate over time in the brain, triggering a series of events that ultimately result in the full-blown neurodegenerative disorder. The hypothesis has been a major driver of AD research for more than 20 years. 

However, in a new study researchers at University of California, San Diego School of Medicine and Veterans Affairs San Diego Healthcare System suggest the picture is not so clear-cut, reporting that early indicators or biomarkers of AD development are not fixed in a specific sequence.

“Our current ability to identify early stages of AD is limited by the focus on amyloid accumulation and the expectation that biomarkers follow the same timeline for all individuals,” said Emily C. Edmonds, PhD, a senior postdoctoral fellow in the Department of Psychiatry and first author of the study.

But, Edmonds said, “AD is complex in the sense that there may be different neurobiological pathways leading to expression of the disease. Our findings suggest that the number of abnormal biomarkers and cognitive markers an individual possesses, without regard to the temporal sequence, is most predictive of future decline.”

“Preclinical AD” is a very early stage of AD prior to the appearance of diagnosable symptoms. Current National Institute of Aging-Alzheimer’s Association (NIA-AA) criteria for preclinical AD describe a disease progression that begins with accumulation of amyloid-beta, leading to neurodegeneration, cognitive decline and, eventually, diagnosable AD.

In their study, researchers classified 570 cognitively normal participants in the Alzheimer’s Disease Neuroimaging Initiative according to NIA-AA criteria, and then separately examined the participants based upon the presence and number of abnormal biological and cognitive markers associated with preclinical AD. They found that neurodegeneration alone was 2.5 times more common than amyloid accumulation alone at baseline measurements.

They then examined only those participants who progressed to a diagnosis of mild cognitive impairment, which is an at-risk cognitive state of AD. They found that it was most common to show neurodegeneration as the first sign of early AD, and equally common to show amyloid accumulation or subtle cognitive decline as the first sign.

Edmonds said that the findings underscore the need to improve identification of persons at risk for AD through the use of multiple, diverse assessment tools. This includes sensitive learning and memory tests capable of reliably identifying cognitive changes at the earliest stages.

“At present, it is much more common for assessment of cognition to be based on insensitive screening measures or reports of cognitive problems by patients or their family members,” said Edmonds. “These blunt screening tools can be very unreliable, which might explain why cognitive decline has traditionally been viewed as occurring later in the disease process. The integration of sensitive neuropsychological measures with assessment of biomarkers of AD can enhance our ability to more accurately identify individuals who are at risk for future progression to AD.” University of California – San Diego

Sleep seems simple enough, a state of rest and restoration that almost every vertebrate creature must enter regularly in order to survive. But the brain responds differently to stimuli when asleep than when awake, and it is not clear what brain changes happen during sleep. “It is the same brain, same neurons and similar requirements for oxygen and so on, so what is the difference between these two states?” asks Rodolfo Llinás, a professor of Neuroscience at New York University School of Medicine and a Whitman Center Investigator at the Marine Biological Laboratory (MBL) in Woods Hole. In a recent paper, Choi, Yu, Lee, and Llinás announced that a specific calcium channel plays a crucial role in healthy sleep, a key step toward understanding both normal and abnormal waking brain functions.

To tackle the broad question of sleep, Llinás and his colleagues focused on one crucial part of the puzzle in mice. Calcium channels, selective gates in neuron walls, are integral in neuron firing, ensuring that all parts of the brain keep talking to one other. But during sleep, calcium channel activity is increased, keeping a slow rhythm that is different from patterns found during wakefulness. Based on this clue, the scientists removed one type of calcium channel, Cav3.1, and looked at how the absence of that channel’s activity affected mouse brain function.

This calcium channel turns out to be a key player in normal sleep. The mice without working Cav3.1 calcium channels took longer to fall asleep than normal mice, and stayed asleep for much shorter periods. “They basically took cat naps,” says Llinás. Their brain activity was also abnormal, more like normal wakefulness than sleep. Most importantly, these mice never reached deep, slow-wave sleep. “This means that we have discovered that Cav3.1 is the channel that ultimately supports deep sleep,” Llinás says.

Because these mice completely lack the ability to sleep deeply, they eventually express a syndrome similar to psychiatric disorders in humans. Llinás believes that studying how the brain functions during unconsciousness is key to understanding normal consciousness, as well as abnormal brain activity. This paper begins to uncover one of the key mechanisms of normal sleep, as well as the role for one important calcium channel in overall brain function. The Marine Biological Laboratory

This September 8-11, the Association for Mass Spectrometry: Applications to the Clinical Lab (MSACL) will be hosting the 2^nd European Congress at the Salzburg Congress Center in Austria. The congress will be prefaced by two days of Short Courses covering the topics of Getting Started with Quantitative LC-MS/MS in the Diagnostic Laboratory, Development and Validation of Quantitative LC-MS/MS Assays for Use in Clinical Diagnostics, Whole-Cell Pathogen Detection by MALDI-TOF MS and Advanced Proteomics Approaches, and A Newbie’s Introduction to the R Statistical Programming Language. The congress will open with an Exhibitor and Poster reception on Wednesday evening to kick-off the main scientific program presented over the following two days, including 36 research-based Podium presentations and Plenary presentations from Linda Thienpont, Douglas Kell, Andy Hoofnagle, Wiebke Arlt and Donald Hunt. Notably, the scientific program will also include a Newbies / Fundamentals track covering introductory topics such as the basic mass spectrometry, compound-specific tuning, developing MRM transitions, LC method development, and sample preparation basics. 

From inception, it has been MSACL’s mission to educate with the aim of developing an understanding of the value of mass spectrometry in the clinic, as well as technical aspects of use, while supporting the growth and attendance of young scientists who are shaping the field. To this end, MSACL provides an expansive Travel Grant program to recruit the attendance of Young Investigators, Trainees and Lab Directors. This year, MSACL is providing 144 grants for the 2015 US conference and 68 for the upcoming 2015 EU congress – approximately 15% of attendees. This investment in the future is supported by the generosity and foresight of Thermo Scientific, Waters, Shimadzu and Cambridge Isotope Labs, companies committed towards driving education, in order to accelerate the implementation of mass spectrometry in the clinic.

View the MSACL 2015 EU Preliminary Program at https://www.msacl.org/2015_EU_program.

Poster abstracts are being accepted for consideration through July 15.

If you are interested in attending the US version of MSACL, Travel Grant applications as well as Podium and Poster Abstracts may be submitted for the MSACL 2016 US conference to be held in Palm Springs, California from February 21-25, 2016.

MSACL is a non-profit educational association dedicated to the advancement of mass spectrometry in the clinical laboratory. More information is available at http://www.msacl.org

Lupus, multiple sclerosis, and type-1 diabetes are among more than a score of diseases in which the immune system attacks the body it was designed to defend. But just why the immune system begins its misdirected assault has remained a mystery.

Now, researchers at Temple University School of Medicine (TUSM) have shown that bacterial communities known as biofilm play a role in the development of the autoimmune disease systemic lupus erythematosus — a discovery that may provide important clues about several autoimmune ailments.

A team led by TUSM researchers Çagla Tükel, PhD, and Stefania Gallucci, MD, show how bacterial biofilms found in the gut can provoke the onset of lupus in lupus-prone mice. Dr. Tükel is an Assistant Professor of Microbiology and Immunology at TUSM, and Dr. Gallucci is Associate Chair, Microbiology and Immunology, as well as an Associate Professor in Microbiology and Immunology at TUSM. Both are members of the Temple Autoimmunity Center.

‘This work stresses the importance of considering infections as a possible trigger for lupus,’ Dr. Gallucci said. ‘Very little was known about how biofilms interact with the immune system because most of the research has been looking at how biofilms protect bacteria, how they make bacteria resistant to antimicrobials such as antibiotics, but almost nothing was known about what biofilms do to the immune response,’ she said.

Biofilm is a densely packed bacterial community that excretes proteins and other substances. Those substances form a matrix that protects the bacteria from antimicrobials, the immune system, and other stressors. Biofilms can occur in our guts, among the bacteria that help us digest. They exist as dental plaque, or arise in urinary tract infections. They also can find a home on man-made surfaces such as intravenous catheters. Central to the lupus story is a biofilm protein deposit called an amyloid. In the common gut bacteria E. coli, as well as the bacteria often responsible for severe gastrointestinal distress that accompanies food poisoning, Salmonella Typhimurium, amyloids are called curli because of their curly fibre-like appearance.

Also part of the biofilm is DNA excreted by bacteria. The Temple team discovered that when curli amyloids and DNA meet, they form remarkably durable bonds in the biofilm. When the researchers attempted to separate the DNA from these bonds using a variety of enzymes as well as chemicals, the curli wouldn’t let go. Curli-DNA complexes speed up the creation of the biofilm, the researchers learned. And the Temple researchers found it is also in this composite of curli-plus-DNA that autoimmune trouble appears to arise.

It’s long been known that infection is associated with lupus flares — a flare in lupus is when symptoms worsen. Indeed, infections play a role in between 20 percent and 55 percent of lupus patient mortality. Up to 23 percent of hospitalizations in lupus patients are due to infectious disease complications. Further, the bacteria Salmonella are more aggressive in lupus patients, with the ability to create potentially lethal complications.

The new research shows that the complexes formed from curli amyloid and DNA in the biofilms of both Salmonella and E. coli give rise to not only inflammation, but the self-attacking antibodies of lupus.

To demonstrate the role of biofilms in immune response, the researchers wanted to see how the sentinels of the immune system, called dendritic cells, reacted to a biofilm. The dendritic cells sent ‘tendrils’ into the biofilm and ate up part of it to signal other molecules. Further, they produced large amounts of chemicals called proinflammatory cytokines. These cytokines are important in inciting the immune system to act. Among the cytokines was Type-1 interferon, known to be associated with lupus.

‘I was super excited when I saw how activated the dendritic cells were on the biofilm ‘ Dr. Gallucci said. The levels of cytokines released when dendritic cells were exposed to curli-DNA complexes actually exceeded the most robust response known previously — the response to lipopolysaccharide (LPS).

To test if the immune response seen in the laboratory would be enough to induce autoimmunity and the attack on self that occurs in lupus, the researchers used mice that are prone to develop autoimmune disease. As is the case with many diseases, lupus is the result of a genetic propensity that lies dormant in the absence of an environmental trigger. The researchers wanted to see if the curli-DNA complexes could provide that trigger. They injected susceptible mice with the amyloid-DNA composites or a placebo. Within two weeks, the researchers found the kind of antibodies that attack ‘self,’ known as autoantibodies. The autoantibodies, which target double-stranded DNA, are a diagnostic hallmark of lupus. The response was remarkably fast. It normally takes mice four to five months to develop autoantibodies.

Another strain of mice that do not develop lupus spontaneously but are genetically predisposed to autoimmunity also reacted to the curli-DNA composites with rapid production of autoantibodies. A third strain of mice with no propensity for any autoimmune disease, developed autoantibodies within two weeks of injection, but at lower levels than in the mice with a propensity toward lupus.

All mice developed the autoantibodies whether the curli-DNA composites came from Salmonella or from the kind of E. coli that’s found in a healthy digestive system. In fact, three of the four bacterial families that contain curli genes are found in the gut: Bacteroidetes, Proteobacteria, and Firmicutes, suggesting a possible source of vulnerability in susceptible patients. ‘How that happens, I think that will be the next level of our project,’ Dr. Gallucci said. The research team is already looking at mouse models to see what may lead to the escape of curli-DNA complexes from the gut. Further, the team is collaborating with rheumatologist Dr. Roberto Caricchio, Director of the Temple Lupus Clinic, to see if the patients show signs of exposure to the curli-DNA complexes.

‘The next step is to explore the mechanism of how these composites are stimulating autoimmunity,’ Dr. Tükel said. ‘The beneficial bacteria found in our guts can cause problems when they cross the intestinal barrier and reach to places they shouldn’t be. Thus, besides infectious bacteria, a leaky gut could cause many problems. We are now starting to understand how the bacteria in our gut may trigger complex human diseases including lupus. So it’s critical for us to understand the biology of the bacterial communities and their interactions with the immune system.’ EurekAlert

Insulin resistance affects tens of millions of Americans and is a big risk factor for heart disease. Yet, some people with the condition never develop heart disease, while some experience moderate coronary blockages. Others, though, get severe atherosclerosis – multiple blockages and deterioration of coronary arteries characterized by thick, hard, plaque-ridden arterial walls. Researchers at the UNC School of Medicine created a first-of-its-kind animal model to pinpoint two biomarkers that are elevated in the most severe form of coronary disease.

The study suggests two new targets – oxidized LDL cholesterol and glycated proteins (i.e., fructosamine or haemoglobin A1c) – that researchers can further investigate and perhaps target through medications to help people with insulin resistance avoid the worst kind of heart disease.

“If these correlations were also found in insulin resistant humans, then we would want to do everything we could to treat them because they would be at a very high risk of developing severe cardiovascular disease,” said Timothy Nichols, MD, professor of medicine and pathology and first author of the PLoS One paper.

Interestingly, Nichols and his colleagues did not set out to pinpoint the two key biomarkers. They wanted to create an insulin resistant animal model that mimicked human heart disease. They chose pigs, which are metabolically similar to humans and have hearts very much like human hearts. By feeding the animals a diet high in fat and salt over the course of a year, all the pigs became insulin resistant. That is, their bodies produced a lot of insulin but their cells did not respond to the hormone as well as normal. All the pigs also developed coronary and aortic atherosclerosis. But only about half of the pigs developed the most severe form of the disease.

When the researchers checked the pigs for high levels of insulin resistance, they found no correlation with the most severe atherosclerosis. This was a surprising and unexpected finding.

David Clemmons, MD, the Sarah Graham Kenan Professor of Medicine, professor of biochemistry and biophysics, and senior author of the PLoS One paper, knew that the scientific literature suggested a correlation between atherosclerosis and glycated proteins – proteins bonded with sugars in blood.

Clemmons and colleagues tested the pigs for high levels of fructosamine and oxidized LDL cholesterol, which are surrogates for high levels of glycated proteins. Sure enough, all the pigs with severe heart disease had elevated levels of fructosamine and oxidized LDL.

“Also, this correlation was more common in females,” Clemmons said. Fourteen of the 20 pigs that developed severe atherosclerosis were females. Fourteen of the 17 pigs that did not develop severe atherosclerosis were male. “This surprised me, so I looked in the literature for anything similar.”

Clemmons found a study from Finland published in 2005 showing that elevated glycated protein levels were strongly associated with advanced heart disease and increased mortality in women but not in men.

“The underlying causes of this correlation are unknown,” Clemmons said. “But now we have a unique animal model that very much mimics what we see in humans. Our model is a good predictor of diet-induced atherosclerosis in females.”

A next step could be to study the affected heart tissue to find abnormal biochemical reactions in the cellular pathways involved in glycated proteins and severe coronary disease.  This could lead to potential new treatment approaches or tailored dietary interventions. University of North Carolina Health Care