Posts tagged caffeine
Articles and news from the latest research reports.
Caffeine’s effect on the brain’s adenosine receptors visualized for the first time
Scans allow researchers to study the link between caffeine and neurodegenerative disorders.
Molecular imaging with positron emission tomography (PET) has enabled scientists for the first time to visualize binding sites of caffeine in the living human brain to explore possible positive and negative effects of caffeine consumption. According to research published in the November issue of The Journal of Nuclear Medicine, PET imaging with F-18-8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine (F-18-CPFPX) shows that repeated intake of caffeinated beverages throughout a day results in up to 50 percent occupancy of the brain’s A1 adenosine receptors.
"The effects of caffeine to the human body are generally attributed to the cerebral adenosine receptors. In the human brain the A1 adenosine receptor is the most abundant," said David Elmenhorst, MD, lead author of "Caffeine Occupancy of Human Cerebral A1 Adenosine Receptors: In Vivo Quantification with F-18-CPFPX and PET." "In vitro studies have shown that commonly consumed quantities of caffeine have led to a high A1 adenosine occupancy. Our study aimed to measure the A1 adenosine receptor occupancy with in vivo imaging."
Caffeine may block inflammation linked to mild cognitive impairment
(Image credit: chichacha)
Recent studies have linked caffeine consumption to a reduced risk of Alzheimer’s disease, and a new University of Illinois study may be able to explain how this happens.
“We have discovered a novel signal that activates the brain-based inflammation associated with neurodegenerative diseases, and caffeine appears to block its activity. This discovery may eventually lead to drugs that could reverse or inhibit mild cognitive impairment,” said Gregory Freund, a professor in the U of I’s College of Medicine and a member of the U of I’s Division of Nutritional Sciences.
Freund’s team examined the effects of caffeine on memory formation in two groups of mice—one group given caffeine, the other receiving none. The two groups were then exposed to hypoxia, simulating what happens in the brain during an interruption of breathing or blood flow, and then allowed to recover.
The caffeine-treated mice recovered their ability to form a new memory 33 percent faster than the non-caffeine-treated mice. In fact, caffeine had the same anti-inflammatory effect as blocking IL-1 signaling. IL-1 is a critical player in the inflammation associated with many neurodegenerative diseases, he said.
“It’s not surprising that the insult to the brain that the mice experienced would cause learning memory to be impaired. But how does that occur?” he wondered.
The scientists noted that the hypoxic episode triggered the release of adenosine by brain cells.
“Your cells are little powerhouses, and they run on a fuel called ATP that’s made up of molecules of adenosine. When there’s damage to a cell, adenosine is released,” he said.
Just as gasoline leaking out of a tank poses a danger to everything around it, adenosine leaking out of a cell poses a danger to its environment, he noted.
The extracellular adenosine activates the enzyme caspase-1, which triggers production of the cytokine IL-1β, a critical player in inflammation, he said.
“But caffeine blocks all the activity of adenosine and inhibits caspase-1 and the inflammation that comes with it, limiting damage to the brain and protecting it from further injury,” he added.
Caffeine’s ability to block adenosine receptors has been linked to cognitive improvement in certain neurodegenerative diseases and as a protectant against Alzheimer’s disease, he said.
“We feel that our foot is in the door now, and this research may lead to a way to reverse early cognitive impairment in the brain. We already have drugs that target certain adenosine receptors. Our work now is to determine which receptor is the most important and use a specific antagonist to that receptor,” he said.
The study appears in the Journal of Neuroscience and can be viewed online at http://www.jneurosci.org/content/32/40/13945.full
(Source: news.aces.illinois.edu)
Caffeinated Coffee Linked to Loss of Vision
Consumption of caffeinated coffee is associated with an increased risk of developing exfoliation glaucoma, the leading cause of secondary glaucoma worldwide, according to a new study led by Dr Louis Pasquale of Brigham and Women’s Hospital in Boston.
Scientists have claimed to have solved the mystery of why coffee never tastes as good as it smells.
Apparently, the act of swallowing the drink sends a burst of aroma up the back of the nose from inside the mouth, activating a “second sense of smell” in the brain that is less receptive to the flavour, causing a completely different and less satisfying sensation.
“We have got two senses of smell. One sense is when you inhale things from the environment into you, and the other is when the air comes out of you up the nasal passage and is breathed out through the nose,” the Telegraph quoted Prof Barry Smith, of the University of London, as saying at the British Science Festival in Aberdeen.
The phenomenon is down to the fact that, although we have sensors on our tongue, 80 percent of what we think of as taste actually reaches us through smell receptors in our nose, the paper said. The receptors, which relay messages to our brain, react to odours differently depending on which direction they are moving in, it added.
In the case of coffee, the taste is also hampered by the fact that 300 of the 631 chemicals that combine to form its complex aroma are wiped out by saliva, causing the flavour to change before we swallow it, Prof Smith added.
Study finds new benefit of coffee: It reduces pain
The surprising finding is based on a study involving 48 volunteers who agreed to spend 90 minutes performing fake computer tasks meant to mimic office work. The tasks were known to cause pain in the shoulders, neck, forearms and wrists, and the researchers wanted to compare how people with chronic pain and those who were pain-free tolerated the tasks.
As a matter of convenience, the scientists allowed people to drink coffee before taking the test “to avoid unpleasant effects of caffeine deprivation, e.g. decreased vigor and alertness, sleepiness, and fatigue,” they reported.
But when it came time to analyze the data, the researchers from Norway’s National Institute of Occupational Health and Oslo University Hospital noticed that the 19 people who drank coffee reported a lower intensity of pain than the 29 people who didn’t.
In the shoulders and neck, for instance, the average pain intensity was rated 41 (on a 100-point scale) among the coffee drinkers and 55 for the coffee abstainers. Similar gaps were found for all pain sites measured, and coffee’s apparent pain-mitigation effect held up regardless of whether the subjects had chronic pain or not.
The authors of the study, which was published this week in the journal BMC Research Notes, cautioned that since the study wasn’t designed to test coffee’s influence on pain, the results come with many uncertainties. For starters, the researchers don’t know how much coffee the coffee drinkers consumed before taking the computer tests. They also doubt that the coffee drinkers and abstainers were similar in all respects except for their java consumption. Problems like these tend to undermine the importance of the findings. But those reservations are unlikely to trouble the legions of coffee drinkers looking for any reason not to cut back on their daily caffeine habit.
This fluorescent close-up of caffeine was taken in July 2011 by microscopist David McCarthy at the University College London School of Pharmacy, and is one of the Wellcome Image award winners 2012. It shows a caffeine crystal about 40 micrometres across. Multimedia artist Annie Cavanagh painted in the original greyscale image using Photoshop. “I chose stimulating colours because of the nature of caffeine,” she says. “This image took me a day-and-a-half to complete.”
When she started working at UCL, she was fascinated by the sharp, hyper-realistic microscope imagery. Because there are no accepted colours for these micro-scale objects, “it opened up an unlimited range of artistic possibilities,” she says. To tint such pictures, she first removes the monochrome background. “Then I paint the image like a watercolour, blending and shading layers of colours.” she says. Little wonder then, that this image created such a buzz.
(Source: wired.co.uk)
Coffee May Help Some Parkinson’s Disease Movement Symptoms, Research Suggests
"Studies have shown that people who use caffeine are less likely to develop Parkinson’s disease, but this is one of the first studies in humans to show that caffeine can help with movement symptoms for people who already have the disease," said study author Ronald Postuma, MD, MSc, with McGill University in Montreal and the Research Institute of the McGill University Health Center. Postuma is also a member of the American Academy of Neurology.
What Caffeine Really Does to Your Brain
What caffeine does do is one heck of an impersonation. In your brain, caffeine is the quintessential mimic of a neurochemical called adenosine. Adenosine is produced by neurons throughout the day as they fire, and as more of it is produced, the more your nervous system ratchets down.
Your nervous system monitors adenosine levels through receptors, particularly the A1 receptor that is found in your brain and throughout your body. As the chemical passes through the receptors, your adenosine tab increases until your nervous system pays it off by putting you to sleep.
High Blood Caffeine Levels in Older Adults Linked to Avoidance of Alzheimer’s Disease
ScienceDaily (June 4, 2012) — Those cups of coffee that you drink every day to keep alert appear to have an extra perk — especially if you’re an older adult. A recent study monitoring the memory and thinking processes of people older than 65 found that all those with higher blood caffeine levels avoided the onset of Alzheimer’s disease in the two-to-four years of study follow-up. Moreover, coffee appeared to be the major or only source of caffeine for these individuals.
Those cups of coffee that you drink every day to keep alert appear to have an extra perk — especially if you’re an older adult. A recent study monitoring the memory and thinking processes of people older than 65 found that all those with higher blood caffeine levels avoided the onset of Alzheimer’s disease in the two-to-four years of study follow-up. (Credit: © Yuri Arcurs / Fotolia)
Researchers from the University of South Florida and the University of Miami say the case control study provides the first direct evidence that caffeine/coffee intake is associated with a reduced risk of dementia or delayed onset. Their findings will appear in the online version of an article to be published June 5 in the Journal of Alzheimer’s Disease. The collaborative study involved 124 people, ages 65 to 88, in Tampa and Miami.
"These intriguing results suggest that older adults with mild memory impairment who drink moderate levels of coffee — about 3 cups a day — will not convert to Alzheimer’s disease — or at least will experience a substantial delay before converting to Alzheimer’s," said study lead author Dr. Chuanhai Cao, a neuroscientist at the USF College of Pharmacy and the USF Health Byrd Alzheimer’s Institute. "The results from this study, along with our earlier studies in Alzheimer’s mice, are very consistent in indicating that moderate daily caffeine/coffee intake throughout adulthood should appreciably protect against Alzheimer’s disease later in life."
The study shows this protection probably occurs even in older people with early signs of the disease, called mild cognitive impairment, or MCI. Patients with MCI already experience some short-term memory loss and initial Alzheimer’s pathology in their brains. Each year, about 15 percent of MCI patients progress to full-blown Alzheimer’s disease. The researchers focused on study participants with MCI, because many were destined to develop Alzheimer’s within a few years.
Blood caffeine levels at the study’s onset were substantially lower (51 percent less) in participants diagnosed with MCI who progressed to dementia during the two-to-four year follow-up than in those whose mild cognitive impairment remained stable over the same period.
No one with MCI who later developed Alzheimer’s had initial blood caffeine levels above a critical level of 1200 ng/ml — equivalent to drinking several cups of coffee a few hours before the blood sample was drawn. In contrast, many with stable MCI had blood caffeine levels higher than this critical level.
"We found that 100 percent of the MCI patients with plasma caffeine levels above the critical level experienced no conversion to Alzheimer’s disease during the two-to-four year follow-up period," said study co-author Dr. Gary Arendash.
The researchers believe higher blood caffeine levels indicate habitually higher caffeine intake, most probably through coffee. Caffeinated coffee appeared to be the main, if not exclusive, source of caffeine in the memory-protected MCI patients, because they had the same profile of blood immune markers as Alzheimer’s mice given caffeinated coffee. Alzheimer’s mice given caffeine alone or decaffeinated coffee had a very different immune marker profile.
Since 2006, USF’s Dr. Cao and Dr. Arendash have published several studies investigating the effects of caffeine/coffee administered to Alzheimer’s mice. Most recently, they reported that caffeine interacts with a yet unidentified component of coffee to boost blood levels of a critical growth factor that seems to fight off the Alzheimer’s disease process.
"We are not saying that moderate coffee consumption will completely protect people from Alzheimer’s disease," Dr. Cao cautioned. "However, we firmly believe that moderate coffee consumption can appreciably reduce your risk of Alzheimer’s or delay its onset."
Alzheimer’s pathology is a process in which plaques and tangles accumulate in the brain, killing nerve cells, destroying neural connections, and ultimately leading to progressive and irreversible memory loss. Since the neurodegenerative disease starts one or two decades before cognitive decline becomes apparent, the study authors point out, any intervention to cut the risk of Alzheimer’s should ideally begin that far in advance of symptoms.
"Moderate daily consumption of caffeinated coffee appears to be the best dietary option for long-term protection against Alzheimer’s memory loss," Dr. Arendash said. "Coffee is inexpensive, readily available, easily gets into the brain, and has few side-effects for most of us. Moreover, our studies show that caffeine and coffee appear to directly attack the Alzheimer’s disease process."
In addition to Alzheimer’s disease, moderate caffeine/coffee intake appears to reduce the risk of several other diseases of aging, including Parkinson’s disease, stroke, Type II diabetes, and breast cancer. However, supporting studies for these benefits have all been observational (uncontrolled), and controlled clinical trials are needed to definitively demonstrate therapeutic value.
A study tracking the health and coffee consumption of more than 400,000 older adults for 13 years, and published earlier this year in the New England Journal of Medicine, found that coffee drinkers reduced their risk of dying from heart disease, lung disease, pneumonia, stroke, diabetes, infections, and even injuries and accidents.
With new Alzheimer’s diagnostic guidelines encompassing the full continuum of the disease, approximately 10 million Americans now fall within one of three developmental stages of Alzheimer’s disease — Alzheimer’s disease brain pathology only, MCI, or diagnosed Alzheimer’s disease. That number is expected to climb even higher as the baby-boomer generation continues to enter older age, unless an effective and proven preventive measure is identified.
"If we could conduct a large cohort study to look into the mechanisms of how and why coffee and caffeine can delay or prevent Alzheimer’s disease, it might result in billions of dollars in savings each year in addition to improved quality of life," Dr. Cao said.
Source: Science Daily