Transplanting donor islet tissue to a bioengineered omentum—the fatty tissue that drapes from the stomach over the intestines—normalized blood glucose levels in nonhuman primates with type 1 diabetes.
In people with type 1 diabetes, the body’s immune system attacks and destroys insulin-producing β cells that control blood glucose levels and are part of a group of cells in the pancreas called pancreatic islets. In research published in Cell Reports Medicine, a team led by investigators at Massachusetts General Hospital (MGH), a founding member of Mass General Brigham, recently developed an efficient way to transplant pancreatic islets and demonstrated that the method can effectively reverse type 1 diabetes in nonhuman primates.
Pancreatic islet transplantation is a promising treatment approach for type 1 diabetes; however, current methods involving transplanting islets to the liver are inefficient and can result in the loss of as much as half of transplanted β cells due to immune attack. Also, the liver can only accommodate a limited volume of transplanted tissue. Scientists have wondered if an alternative site might provide a more hospitable environment and lead to better results. One promising site is the omentum, the fatty tissue that starts in the stomach and drapes over the intestines.
To optimize the omentum as a transplant site in an individual, investigators used topical recombinant thrombin (which stops bleeding), an enzyme, and the recipient’s own plasma to engineer a bio-degradable matrix by which donor islets are immobilized onto the omentum. When this strategy was used along with an immunosuppressive therapy to protect islets from immune attack, the method normalized blood glucose levels and restored glucose-responsive insulin secretion in three nonhuman primates with type 1 diabetes for as long as the animals were tested. “The achievement of complete glycemic control is attributed to the bioengineering approach that facilitates the process of revascularization and reinnervation for the transplanted islets,” says first author Hong Ping Deng, MD, MSc, a researcher of Transplant Surgery at MGH. “which is the first time that such a demonstration has been made in a nonhuman primate model.”
“This pre-clinical study can inform the development of new strategies for β cell replacement in diabetes and could change the current paradigm of clinical pancreatic islet transplantation,” says senior corresponding author Ji Lei, MD, MBA, MSc, a principal physician investigator of Transplant Surgery at MGH and an assistant professor of Surgery at Harvard Medical School. “A clinical trial is being planned to test this approach.”
Lei, who is also the director of the Human Islet/Cell Processing Special Service cGMP Facility at MGH, notes that in addition to transplanting islets from donors, researchers are also studying the potential broad application of transplanting stem cell–derived islets, which cured a patient with type 1 diabetes for the first time in human history in 2022 and could offer an endless supply of transplantable tissue. There are concerns about this approach, however, including the possibility of tumor development. Unlike the liver, the omentum is easily accessible for monitoring purposes, and its non-vital site status can allow for the removal of transplanted tissue should complications occur, with either stem cell–derived islets or islets from donors. In addition, the engineered omental site can be home to many other types of genetically engineered cells, especially for liver-based or inherited metabolic or endocrine disorders.
More evidence that sugary drinks cause weight gain
A review of dozens of studies from the last decade, led by researchers at the University of Toronto and Harvard University, recently found that sugar-sweetened beverages promote weight gain in children and adults.
The review, published in the American Journal of Clinical Nutrition, is the largest and most thorough analysis to date of research on sweetened drinks, and overweight and obesity — both of which heighten risks for diabetes, heart disease, some cancers and other diseases.
Our last meta-analysis on this topic was 2013. You want to update a meta-analysis every five to 10 years anyway, but especially in this area because there has been so much new research the last decade. Evidence has continued to accumulate showing associations among sugar-sweetened beverages, or SSBs as we call them, and weight and chronic disease. And it’s very important to have an updated synthesis of that evidence, especially for public policy. The Canada Food Guide is clear on the need to limit SSBs and recommends water as the drink of choice, and added sugar intake including SSBs has declined in Canada, in part due to public policies. But levels here are still too high. As well, the USDA Dietary Guidelines for Americans are arguably not as strong, and with U.S. policymakers coming together soon to discuss the 2025 guidelines, our study will be an important piece of evidence to inform their work.
What did your study show?
We expected to find a positive association between SSBs and weight gain, among adults and children, and in cohort studies and randomized clinical trials. And that was exactly what we found. We analyzed 85 studies, which totalled over half a million participants. In cohort studies, which follow people over long periods of time, each serving-per-day increase in SSBs was associated with a 0.42-kg (almost one-pound) higher body weight in adults. In children, we saw a 0.07-unit higher body-mass index (just under one-twelfth of a BMI unit). Perhaps most striking, findings from our dose-response analysis showed that weight gain increases with increasing levels of SSB intake, in both children and adults. A dose–response relationship provides strongevidence for a cause-and-effect relationship.
How much weight gain might one drink a day lead to over time?
Well, we estimated that associated change in body weight over a one-year period. For adults, one additional 12-ounce serving a day was linked to a 0.20-kg higher body weight (about half a pound) in one year. Over 10 years, that could be about five pounds. In children, we observed a 0.03-unit higher BMI for each additional daily serving of SSBs over a one-year period. Although these results may seem modest, weight gain is a gradual process, with adults averaging about one pound (0.45 kg) of weight gain per year. So, limiting SSB consumption could be an effective way to prevent age-related weight gain. Limiting SSB intake among children is also an important strategy to help them develop healthy lifestyle habits and weight trajectories.
How common is excess consumption of these drinks?
It’s very common. Sugar-sweetened beverages include sodas, fruit drinks, sports and energy drinks, and they are the largest source of added sugar in the North American diet. Moreover, the rise in consumption of these drinks has mirrored the epidemic of overweight and obesity. In 2016, almost two billion adults were estimated as having overweight and 650 million had obesity. Even more worrying, the rate of increase in obesity in children and adolescents is now greater than in adults. The prevalence of childhood obesity has increased more than four-fold globally since the 1970s, which is truly alarming.
What are some of the health effects of SSBs?
A typical 12-ounce serving of an SSB contains over 140 calories and more than eight teaspoons of sugar. That nearly reaches the recommended daily limit for added sugar, which is no more than 10 per cent of total calories, or about 200 calories for a 2000-calorie per day diet. These drinks are sugar in liquid form. They’re usually made with table sugar, high-fructose corn syrup or other sweeteners that provide calories, and are digested rapidly, more so than sugar consumed as a solid. This bolus of glucose increases blood sugar levels, which triggers a glycemic response that over time can lead to insulin resistance and diabetes. The fructose component also floods the liver, which can cause lipogenesis (creation of fat), which puts a person on the path to fatty liver and metabolic disease. Fructose also increases uric acid, which contributes to insulin resistance and risk for cardiovascular and other diseases. Insulin spikes from the glycemic response can result in an appetite cascade and over-eating, as can excess insulin in the blood over longer periods. Some evidence shows that SSBs activate the dopaminergic reward system in the brain and encourage addictive behaviour, and that they alter the gut microbiome, but we need more research on those effects.
Are you optimistic, given these effects and the research evidence?
Intake levels of SSBs have come down in the developed world. We’re still seeing increases in the developing world, but taxes in some of those countries are working. Thailand introduced a tax that has reduced consumption, as has Mexico and South Africa. At least 85 countries now have a tax on SSBs, which in part reflects the World Health Organization’s stand on this issue. In Canada, Newfoundland introduced a tax recently, and several U.S. regions and cities have had a tax for years, in response to public health efforts, more awareness and advocacy. The general effect of these taxes is reduced intake, and the revenues can be put toward further public health measures and health care. Other changes will help in Canada and elsewhere as well, such as limiting marketing to children, and better front-of-pack and nutrition labels. All these efforts will push intake down, but it’s important to remember that as that happens, people need access to clean, safe drinking water as an alternative. That’s an ongoing challenge globally, and in many parts of Canada, that we really need to address.
Vasanti Malik holds a Canada Research Chair in Nutrition and Chronic Disease Prevention at the University of Toronto, and an adjunct position in Nutrition at the Harvard T.H. Chan School of Public Health. Michelle Nguyen, a doctoral student at U of T, conducted the study analysis and wrote the paper.
There is this picture – you may have seen it. It is black and white and has two silhouettes facing one another. Or maybe you see the black vase with a white background. But now, you likely see both.
It is an example of a visual illusion that reminds us to consider what we did not see at first glance, what we may not be able to see, or what our experience has taught us to know – there is always more to the picture or maybe even a different image to consider altogether. Researchers are finding the process in our brain that allows us to see these visual distinctions may not be happening the same way in the brains of children with autism spectrum disorder. They may be seeing these illusions differently.
“How our brain puts together pieces of an object or visual scene is important in helping us interact with our environments,” said Emily Knight, MD, PhD, assistant professor of Neuroscience and Pediatrics at the University of Rochester Medical Center, and first author on a study out today in the Journal of Neuroscience. “When we view an object or picture, our brains use processes that consider our experience and contextual information to help anticipate sensory inputs, address ambiguity, and fill in the missing information.”
Watching the brain ‘see’
Knight and fellow neuroscience researchers in the Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory at the Del Monte Institute for Neuroscience used visual illusions – groups of Pac-Man-shaped images that create the illusion of a shape in the empty space. They worked with 60 children ages seven to 17 with and without autism. Using electroencephalography (EEG) – a non-invasive neuroimaging technique that allows researchers to record the response of neurons in the brain – researchers revealed that children with autism did not automatically process the illusory shapes as well as children without autism. It suggests that something is going awry in the feedback processing pathways in their brain.
“This tells us that these children may not be able to do the same predicting and filling in of missing visual information as their peers,” Knight said. “We now need to understand how this may relate to the atypical visual sensory behaviors we see in some children on the autism spectrum.”
Knight’s past research, published in Molecular Autism, found that children with autism may not be able to see or process body language like their peers, especially when distracted by something else. The kids in this study watched videos of dots that moved to represent a person. As part of the experiment, the dots changed color. Unlike in typical development, the brains of children with autism did not appear to notice the human movement when told to focus on the color. They had to pay specific attention to the human movement for their brains to process it well.
“We also need to continue this work with people on the autism spectrum who have a wider range of verbal and cognitive abilities and with other diagnoses such as ADHD,” Knight said. “Continuing to use these neuroscientific tools, we hope to understand better how people with autism see the world so that we can find new ways to support children and adults on the autism spectrum.”
Collaboration aims to reveal more about neurodevelopmental diseases
“As scientists, we always need to pace ourselves. Research is a marathon – not a sprint. But being able to collaborate affords us time, space, and materials we may not otherwise have access to,” said John Foxe, PhD, senior author on both studies and co-director of the UR-IDDRC. “This recent work is a wonderful example of this. We can increase our pace in the marathon by collaborating with others on the IDDRC team.”
Keto and paleo diets were found to be the least sustainable — and have the lowest diet quality scores — of the six popular diets examined
This may be tough to swallow for those on keto or paleo diets.
A new study from Tulane University which compared popular diets on both nutritional quality and environmental impact, found that the keto and paleo diets, as eaten by American adults, scored among the lowest on overall nutrition quality and were among the highest on carbon emissions.
The keto diet, which prioritizes high fat and low carbs, was estimated to generate almost 3 kg of carbon dioxide for every 1,000 calories consumed. The paleo diet, which eschews grains and beans in favour of meats, nuts and vegetables, received the next lowest diet quality score and also had a high carbon footprint, at 2.6 kg of carbon dioxide per 1,000 calories.
The study, published in The American Journal of Clinical Nutrition, compiled diet quality scores using data from more than 16,000 adult diets collected by the CDC’s National Health and Nutrition Examination Survey. Individual diets were assigned point values based on the federal Healthy Eating Index and average scores were calculated for those eating each type of diet.
The study’s senior author Diego Rose, professor and nutrition program director at Tulane University School of Public Health and Tropical Medicine, said that while researchers have examined the nutritional impact of keto and paleo diets, this is the first study to measure the carbon footprints of each diet, as consumed by U.S. adults, and compare them to other common diets.
“We suspected the negative climate impacts because they’re meat-centric, but no one had really compared all these diets – as they are chosen by individuals, instead of prescribed by experts – to each other using a common framework,” Rose said.
On the other end of the spectrum, a vegan diet was found to be the least impactful on climate, generating 0.7 kg of carbon dioxide per 1,000 calories consumed, less than a quarter of the impact of the keto diet. The vegan diet was followed by vegetarian and pescatarian diets in increasing impact.
The pescatarian diet scored highest on nutritional quality of the diets analyzed, with vegetarian and vegan diets following behind.
The omnivore diet – the most common diet, represented by 86% of survey participants – sat squarely in the middle of the pack of both quality and sustainability. Based on the findings, if a third of those on omnivore diets began eating a vegetarian diet, on average for any given day, it would be equivalent to eliminating 340 million passenger vehicle miles.
Notably, however, when those on omnivorous diets opted for the plant-forward Mediterranean or fatty meat-limiting DASH diet versions, both carbon footprints and nutritional quality scores improved.
“Climate change is arguably one of the most pressing problems of our time, and a lot of people are interested in moving to a plant- based diet,” Rose said. “Based on our results, that would reduce your footprint and be generally healthy. Our research also shows there’s a way to improve your health and footprint without giving up meat entirely.”
A 2021 United Nations-backed study found that 34% of greenhouse gas emissions come from the food system. The major share of those emissions come from food production, with beef being responsible for 8-10 times more emissions than chicken production and over 20 times more emissions than nut and legume production.
While the environmental impacts of specific foods have been studied extensively, Rose said this study was important because “it considers how individuals select popular diets that are composed of a wide variety of foods.”
Going forward, Rose still has questions about how to encourage eating habits that are better for people and the planet.
“I think the next question is how would different policies affect outcomes and how could those move us toward healthier, more environmentally friendly diets?” Rose said.
How many steps should I walk per day to stay healthy? This video will summarize the major health benefits of daily walking and how many steps you need to maximize those effects. Benefits include improved mortality, decreased cardiovascular risk, improved cognition, better immune response, and more robust mental health.
Physical activity is crucial to living a healthy lifestyle. It improves our heart and lung function. It lowers our cholesterol and blood sugar. It increases metabolism to help us lose weight. It improves our sleep and mental health. And it helps us learn and concentrate. Daily step counts are an easy indirect measure of physical activity. Increased step counts have been shown to decrease mortality and decrease cardiovascular risk. More daily steps help with cognition especially with better attention, executive function, language, and memory. Increased daily walking helps boost our immune system and prevent dying from serious infections such as pneumonia. More step counts also improve mental health and decrease stress, anxiety, and depression.
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