Category: Metabolic Disorders

Categories : Cardiovascular Disease Metabolic DisordersTags :

New Research Points to Clot Lysis Protein for Cholesterol Control

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Source: Wikimedia CC0

While high levels of low-density lipoprotein (LDL) can be reduced by drugs such as statins, reducing the risk of myocardial infarction and stroke, risk still remains in the form of other cholesterols. New research published in the journal Science describes how manipulating a protein involved in blood clot lysis could help bring cholesterol levels even more under control.

Heart disease remains a leading cause of death worldwide, despite advances in cholesterol-lowering medication such as proprotein convertase subtilisin-kexin type 9 inhibitors, which were approved by the FDA in 2015. One clinical trial following patients taking proprotein convertase subtilisin-kexin type 9 inhibitors demonstrated a benefit while also revealing an opportunity for improvement as the absolute risk reduction was considered modest at 1.5%.

“It is clear that there is more going on than just what statins and these newer inhibitor drugs can control,” says Ze Zheng, MBBS, PhD, MCW assistant professor of medicine. “More therapies are needed, and to get them we need to know more about other sources of risk for heart disease, especially heart attacks and strokes.”

So-called “bad cholesterol” is carried by apolipoprotein B (apoB) which forms well-structured particles with lipids and proteins. These particles serve as stable vehicles for transporting lipids such as cholesterol in the bloodstream. These lipid-rich particles mostly include very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL). Current cholesterol-lowering reduce mainly LDL levels, which though important to control, is not the only risk factor for heart disease. In fact, the other lipoproteins in the same group as LDL are not reduced by much with available treatments. Dr Zheng and her team are investigating how to reduce levels of other members of this family of lipoproteins, especially VLDL.

“With my background in lipid metabolism, I found myself consistently checking lipid levels even during studies regarding blood clot lysis and how an impairment in the body’s ability to remove blood clots affects the risk of blood vessel blockages,” Dr Zheng adds. “I was just naturally curious about it, and I noticed that a protein I was studying may have an effect on the amount of circulating cholesterol.”

In prior research, Dr Zheng has helped define a new cellular source of this protein, tissue-type plasminogen activator (tPA), and its role in breaking down blood clots and preventing blood vessel blockages. To understand its potential influence on cholesterol levels, her team used a gene-editing technique to stop liver cells from producing tPA in mice prone to blood vessel plaque formation. The scientists found that the mice developed increased lipoprotein-cholesterol in this experiment, and then validated the findings in follow-up studies using human liver cells and a type of rat liver cell known to produce VLDL in a way similar to human liver cells. With these and other experimental results, Dr Zheng and her team have demonstrated a new, important role that liver tPA influences blood cholesterol levels while underscoring a meaningful connection between the liver, heart and blood vessels.

“After defining this new role for tPA, we turned our attention to the question of how it changes blood cholesterol levels,” notes Wen Dai, MD, research scientist, Versiti Blood Research Institute.

The liver contributes to the majority of the “bad” apoB-lipoproteins by making VLDL. The team focused on whether and how tPA impacts the process of VLDL assembly in the liver. Microsomal triglyceride transfer protein (MTP) is required for the assembly of VLDL due to its role carrying lipids to the apoB. The scientists determined that tPA binds with the apoB protein in the same place as MTP. The more tPA is present, the fewer opportunities MTP has to connect with apoB and catalyse the creation of new VLDL. Essentially, MTP tries to pass a cholesterol to apoB, but tPA interferes with this pocess.

“Based on our prior research, we knew it also was critical to look at tPA’s primary inhibitor,” Dr. Zheng says.

Plasminogen activator inhibitor-1 (PAI-1) is known to block the activity of tPA. Scientists also have found a correlation between PAI-1 levels in blood and the development of disease due to plaque formation and blockages in blood vessels. The team found that higher levels of PAI-1 reduced the ability of tPA to bind with apoB proteins, rendering tPA less effective at competing with MTP to prevent VLDL production. Returning to the biological gridiron, PAI-1 might be a decoy receiver that distracts tPA until MTP connects with apoB for a big gain. The team studied this interaction in human subjects with a naturally occurring mutation in the gene carrying the code for PAI-1. The researchers found that these individuals, as predicted, had higher tPA levels and lower LDL and VLDL levels than individuals from the same community who did not have the same mutation.

“We are investigating therapeutic strategies based on these findings regarding tPA, MTP and PAI-1,” Dr Zheng notes. “I think we may be able to reduce the residual cardiovascular risk that has persisted even as treatment has advanced.”

Source: Medical College of Wisconsin

Categories : Metabolic DisordersTags :

Semaglutide Eliminates Insulin Injections in Some Newly-diagnosed Type 1 Diabetes Patients

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Novolog insulin pen. Photo by Dennis Klicker on Unsplash

Treating newly diagnosed Type 1 diabetes patients with semaglutide may drastically reduce or even eliminate their need for injected insulin, according to the remarkable findings of a small University at Buffalo study reported in the New England Journal of Medicine.

“Our findings from this admittedly small study are, nevertheless, so promising for newly diagnosed Type 1 diabetes patients that we are now absolutely focused on pursuing a larger study for a longer period of time,” says Paresh Dandona, MD, PhD, professor and senior author on the paper.

A total of 10 patients at UB’s Clinical Research Center in the Division of Endocrinology were studied from 2020 to 2022, all of whom had been diagnosed in the past three to six months with Type 1 diabetes. The mean HbA1c level over 90 days at diagnosis was 11.7, far above the American Diabetes Association’s HbA1c recommendation of 7 or below.

The patients were treated first with a low dose of semaglutide while also taking meal-time (bolus) insulin and basal (background) insulin. As the study continued, semaglutide dosing was increased while mealtime insulin was reduced in order to avoid hypoglycaemia.

“Within three months, we were able to eliminate all of the mealtime insulin doses for all of the patients,” says Dandona, “and within six months we were able to eliminate basal insulin in 7 of the 10 patients. This was maintained until the end of the 12-month follow-up period.”

During that time, the patients’ mean HbA1c fell to 5.9 at six months and 5.7 at 12 months.

Applying Type 2 diabetes drugs to treat Type 1 diabetes

For more than a decade, Dandona has been interested in how drugs developed for Type 2 diabetes might be utilized in treating Type 1 diabetes as well.

He and his colleagues were the first to study how liraglutide, another drug for Type 2 diabetes, might work in patients with Type 1 diabetes in a study he published in 2011.

“As we extended this work, we found that a significant proportion of such diabetics still have some insulin reserve in the beta cells of their pancreas,” Dandona explains. “This reserve is most impressive at the time of diagnosis, when 50% of the capacity is still present. This allowed us to hypothesise that semaglutide, which works through stimulation of insulin secretion from the beta cell, could potentially replace mealtime insulin administration.”

From the outset, the goal of the current study was to see if semaglutide treatment could be used to replace mealtime insulin, thereby reducing the insulin dosage, improving glycaemic control, reducing the HbA1c and eliminating potentially dangerous swings in blood sugar and hypoglycaemia.

The most common side effects for patients were nausea and vomiting as well as appetite suppression, which led a number of patients to experience weight loss, an outcome that Dandona says is generally an advantage since 50% of patients with Type 1 diabetes in the US are overweight or obese.

“As we proceeded with the study, we found that even the dose of basal insulin could be reduced or eliminated altogether in a majority of these patients,” he says. “We were definitely surprised by our findings and also quite excited. If these findings are borne out in larger studies over extended follow-up periods, it could possibly be the most dramatic change in treating Type 1 diabetes since the discovery of insulin in 1921.”

Source: University at Buffalo

Categories : Metabolic Disorders Regenerative MedicineTags :

Microvascular Implants may Enable Faster Healing of Chronic Wounds

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Photo by cottonbro studio

Researchers in South Korea have achieved a ground-breaking milestone in tissue regeneration with a technology that utilises autologous blood to produce three-dimensional microvascular implants. These implants hold immense potential for various applications requiring vascular regeneration, including the treatment of chronic wounds in conditions such as diabetes, as well as the potential for scarless healing.

Led by Professor Joo H. Kang from the Department of Biomedical Engineering at UNIST, the team successfully developed a microfluidic system capable of processing blood into an artificial tissue scaffold. Unlike previous methods based on cell-laden hydrogel patches using fat tissues or platelet-rich plasma, this innovative approach enables the creation of robust microcapillary vessel networks within skin wounds. The utilisation of autologous whole blood ensures compatibility and promotes effective wound healing.

Creating optimal stiffness

The technology, described in Advanced Materials, leverages microfluidic shear stresses to align bundled fibrin fibres along the direction of blood flow streamlines while activating platelets. This alignment and activation process results in moderate stiffness within the microenvironment – optimal conditions for facilitating endothelial cell maturation and vascularisation. When applied as patches to rodent dorsal skin wounds, these implantable vascularided engineered thrombi (IVETs) demonstrated superior wound closure rates (96.08 ± 1.58%), increased epidermis thickness, enhanced collagen deposition, hair follicle regeneration, reduced neutrophil infiltration, and accelerated wound healing through improved microvascular circulation.

Chronic wounds pose significant challenges as they often fail to heal properly over time and can lead to complications associated with diabetes and vascular diseases. In severe cases, they may result in sepsis due to insufficient oxygen supply and nutrients caused by loss of blood vessels.

By harnessing the power of microfluidic technology, Professor Kang’s team transformed autologous blood into IVETs suitable for transplantation. These IVETs were implanted into full-thickness skin wounds in experimental mice, resulting in rapid and scarless recovery of the entire damaged area. The study demonstrated successful regeneration of blood vessels within the wound site, facilitated movement of immune cells crucial for wound healing, and accelerated overall recovery.

Furthermore, the team evaluated the efficacy of IVET transplantation by infecting the skin damage area with methicillin-resistant Staphylococcus aureus (MRSA). When artificial blood clots made from autologous blood were implanted into infected mice, quick vascular recovery was observed alongside enhanced migration of proteins and immune cells to combat bacterial infection. Additionally, collagen formation and hair follicle regeneration occurred without scarring.

These ground-breaking findings pave the way for advanced techniques in tissue engineering and wound healing using autologous blood-based implants. With further development and refinement, this technology holds tremendous potential to revolutionise treatment strategies for chronic wounds while contributing to advancements in regenerative medicine.

Source: Ulsan National Institute of Science and Technology (UNIST)

Categories : Diet and Nutrition Metabolic DisordersTags :

Diet Extremes of Carbohydrate and Fat Tied to Sex-specific Mortality Risks

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Photo by I Yunmai on Unsplash

New research suggests that extreme dietary habits involving carbohydrates and fats affect life expectancy. Results published in The Journal of Nutrition show that a low carbohydrate intake in men and a high carbohydrate intake in women are associated with a higher risk of all-cause and cancer-related mortality and that women with higher fat intake may have a lower risk of all-cause mortality. Their findings suggest that people should pursue a balanced diet rather than heavily restricting their carbohydrate or fat intake.

While low-carbohydrate and low-fat diets are becoming popular as a way to promote weight loss and improve blood glucose levels, their long-term effects on life expectancy are less clear. Interestingly, recent studies conducted in Western countries suggest that extreme dietary habits for carbohydrates and fats are associated with a higher risk of mortality. However, few studies have explored these associations in East Asian populations, including Japanese individuals who typically have relatively low fat and high-carbohydrate dietary intakes.

Researchers from Nagoya University Graduate School of Medicine in Japan led by Dr Takashi Tamura conducted a follow-up survey over a period of 9 years with 81 333 Japanese people (34,893 men and 46 440 women) to evaluate the association between carbohydrate and fat intakes and the risk of mortality. Daily dietary intakes of carbohydrates, fats, and total energy were estimated using a food frequency questionnaire and calculated as a percentage of total energy intake for carbohydrates and fats. Carbohydrate intake quality (ie, refined compared with minimally processed carbohydrate intake) and fat intake quality (ie, saturated compared with unsaturated fat intake) were also assessed to examine the impact of food quality on the association with mortality.

They found that men who consumed less than 40% of their total energy from carbohydrates experienced significantly higher risks of all-cause and cancer-related mortality. The trend was observed regardless of whether refined or minimally processed carbohydrate were considered. On the other hand, among women with 5 years or longer of follow-up, those with a high carbohydrate intake of more than 65% had a higher risk of all-cause mortality. No clear association was observed between refined or minimally processed carbohydrate intake and the risk of mortality in women.

For fats, men with a high fat intake of more than 35% of their total energy from fats had a higher risk of cancer-related mortality. They also found that a low intake of unsaturated fat in men was associated with a higher risk of all-cause and cancer-related mortality. In contrast, total fat intake and saturated fat intake in women showed an inverse association with the risk of all-cause and cancer-related mortality. They concluded that this finding does not support the idea that high fat intake is detrimental to longevity in women.

“The finding that saturated fat intake was inversely associated with the risk of mortality only in women might partially explain the differences in the associations between the sexes,” Dr Tamura stated. “Alternatively, components other than fat in the food sources of fat may be responsible for the observed inverse association between fat intake and mortality in women.”

This study is extremely important because restricting carbohydrates and fats, such as extremely low-carbohydrate and low-fat diets, are now popular dieting strategies aimed at improving health, including the management of metabolic syndrome. However, this study shows that low-carbohydrate and low-fat diets may not be the healthiest strategy for promoting longevity, as their short-term benefits could potentially be outweighed by long-term risk.

Overall, an unfavourable association with mortality was observed for low-carbohydrate intake in men and for high carbohydrate intake in women, whereas high fat intake could be associated with a lower mortality risk in women. The findings suggest that individuals should carefully consider how to balance their diet and ensure that they are taking in energy from a variety of food sources, while avoiding extremes.

Source: Nagoya University

Categories : Implants and Prostheses Metabolic DisordersTags :

Implanted Bioreactors Functioning as Artificial Kidneys Could One Day Replace Dialysis

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Photo by Robina Weermeijer on Unsplash

Scientists at UC San Francisco are working on a new approach to treating kidney failure that could one day free people from needing dialysis or a transplant and the associated immunosuppressive drugs.

The technology, described in Nature Communications, shows for the first time that kidney cells, housed in an implantable device called a bioreactor, can survive inside the body of a pig and mimic several important kidney functions. The device can work quietly in the background, like a pacemaker, and does not trigger the recipient’s immune system to go on the attack.

Eventually, scientists plan to fill the bioreactor with different kidney cells that perform vital functions like balancing the body’s fluids and releasing hormones to regulate blood pressure, then pair it with a device that filters waste from the blood.

The aim is to produce a human-scale device to improve on dialysis, which keeps people alive after their kidneys fail but is a poor substitute for having a real working organ. In the US, more than 500 000 require dialysis several times a week. Many seek kidney transplants, but there are not enough donors, and only about 20 000 people receive them each year. An implantable kidney would be a boon.

This is a key step forward is for The Kidney Project, which is jointly headed by UCSF’s Shuvo Roy, PhD (technical director) and Vanderbilt University Medical Center’s William H. Fissell, MD (medical director).

“We are focused on safely replicating the key functions of a kidney,” said Roy, a bioengineering professor in the UCSF School of Pharmacy. “The bioartificial kidney will make treatment for kidney disease more effective and also much more tolerable and comfortable.”

Inspired by nature, honed by science

Roy and his colleagues engineered the bioreactor to connect directly to blood vessels and veins, allowing the passage of nutrients and oxygen, much like a transplanted kidney would. Silicon membranes keep the kidney cells inside the bioreactor safe from attack by the recipient’s immune cells.

The team used a proximal tubule cell, which regulates water, as a test case. Co-author H. David Humes, MD, from the University of Michigan, had previously used these cells to help dialysis patients in the intensive care unit with life-saving results.

No immunosuppression needed

The team tracked the renal cells and the recipient animals for seven days after transplantation and both did well. The next step will be month-long trials, as required for by the U.S. Food and Drug Administration (FDA), first in animals and eventually in humans.

“We needed to prove that a functional bioreactor will not require immunosuppressant drugs, and we did,” Roy said. “We had no complications and can now iterate up, reaching for the whole panel of kidney functions at the human scale.”

Source: University of California – San Francisco

Categories : Metabolic DisordersTags :

Urine Adenine Predicts Kidney Failure in Diabetes up to a Decade in Advance

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Urine levels of adenine, a metabolite produced in the kidney, are predictive and a causative biomarker of looming progressive kidney failure in patients with diabetes, a finding that could lead to earlier diagnosis and intervention, researchers reported in the Journal of Clinical Investigation. Elevated adenine was also associated with all-cause mortality.

The study results are significant because until now, the most important marker for kidney disease has been protein (or albumin) in the urine. Up to half of diabetes patients who develop kidney failure never have much protein in their urine. As 90% of patients with diabetes remain at increased risk despite low levels of albumin in their urine, this study has widespread consequences. It is the first study to identify these patients at an early stage by measuring this new causative marker in the urine.

The finding paves the way for clinic testing to determine that a patient is at risk, five to 10 years before kidney failure, said the senior study author, Kumar Sharma, MD. The study was conducted by The University of Texas Health Science Center at San Antonio.

Importantly, the research team identified a small molecule that blocks the major pathway of endogenous adenine production in the body. This therapeutic drug reduced kidney adenine levels in mice with type 2 diabetes. “The drug protected against all the major aspects of diabetic kidney disease without affecting blood sugar,” Sharma said. “The study is remarkable as it could pave the way to precision medicine for diabetic kidney disease at an early stage of the disease.”

Findings consistent across diverse study populations

The researchers studied more than 1200 patients with diabetes across three international research cohorts. The Chronic Renal Insufficiency Cohort (CRIC) study included African American, Hispanic and Caucasian participants in the US. A separate study was in the American Indian population. The team also evaluated an Asian cohort of mostly Chinese, Asian Indians and Malay populations in a study based in Singapore.

Mapping the metabolites

UT Health San Antonio is one of few centres perfecting a technique called spatial metabolomics on kidney biopsies from human patients. This technique enables researchers to determine the locations of adenine and other small molecules in kidney tissues.

“It’s a very difficult technique, and it took us several years to develop a method where we combine high resolution of the geography of the kidney with mass spectrometry analysis to look at the metabolites,” Sharma said.

Metabolites are small molecules that the body produces based on metabolism. They make cells go in a healthy way or in a disease pattern, Sharma said.

Adenine situated around kidney blood vessels

The team found endogenous adenine around scarred blood vessels in the kidney and around tubular-shaped kidney cells that were being destroyed. Endogenous substances are those that naturally occur in the body.

The finding that high levels of adenine were also associated with all-cause mortality in the study participants suggests that the metabolite is affecting other parts of the body, as well, Sharma said.

False sense of security

Many patients with diabetes know they’re at risk of kidney disease, but if they don’t have protein in their urine, they think they are protected, he said.

“They could be feeling a false sense of security that there is no kidney disease occurring in their body,” Sharma said. “But in fact, in many cases it is progressing, and they often don’t find out until the kidney disease is pretty far advanced. And at that time, it is much harder to protect the kidneys and prevent dialysis.”

“The death rate is very high, especially in patients with diabetes,” Sharma said. “There is about 40% mortality within five years in patients with diabetes and kidney failure.”

New type of therapy is needed

Although treatments to protect against diabetes and blood pressure are improving, they only push the envelope a little bit, Sharma said, in that patients still have progressive kidney disease and kidney failure, but they are afforded more time before they reach that endpoint. The measurement of urine adenine is difficult; however, the team at the Center for Precision Medicine at UT Health San Antonio has developed a robust and sensitive method to measure urine adenine in patients.

“What we’re hoping is that by identifying patients early in their course and with new therapies targeting adenine and kidney scarring, we can block kidney disease or extend the life of the kidney much longer,” Sharma said.

Source: University of Texas Health Science Center at San Antonio

Categories : Metabolic DisordersTags :

Don’t Overlook Latent Autoimmune Diabetes in Adults, Researchers Caution

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To reduce the risk of complications, it is important to measure antibodies those with adult onset diabetes, while also considering the levels of these antibodies.

In a study published in the journal Diabetes Care, researchers demonstrate that individuals with Latent Autoimmune Diabetes in Adults (LADA) have an equally high risk of developing cardiovascular disease as people with type 2 diabetes, but a higher risk of developing retinopathy and poorer glucose control. Many also lack adequate treatment.

LADA is a common but relatively unknown form of diabetes. Similar to type 1 diabetes, it is an autoimmune disease characterised by antibodies against insulin-producing cells. It develops in adulthood, and the autoimmune process progresses more slowly than in type 1 diabetes. LADA also shares features with type 2 diabetes, which means those affected risk getting the wrong diagnosis if antibodies are not measured. Incorrect diagnosis can result in inadequate treatment. Previous studies suggest that between five and ten percent of all individuals initially diagnosed with type 2 diabetes actually have LADA. Researchers at Karolinska Institutet, and the Universities of Lund and Helsinki set out to examine the risk of complications in LADA.

Our results emphasise the importance of diagnosing LADA correctly and careful monitoring of glucose control in these individuals, so that treatment can be intensified if needed, thereby reducing the risk of complications.

Yuxia Wei, PhD-student and Sofia Carlsson, senior lecturer, Institute of Environmental Medicine, Karolinska Institutet

According to the study LADA was characterised by fewer metabolic risk factors than type 2 diabetes, such as high blood pressure and high blood lipids. However, a lower proportion of individuals with LADA achieved good glucose control. The lack of glucose control was most evident in LADA patients with high levels of the antibody GADA (glutamic acid decarboxylase antibody). A significant portion of individuals with LADA lacked any glucose-lowering treatment.

The results of the new study are based on the ESTRID study, where researchers followed over 4000 individuals with diabetes, of whom 550 had LADA, for up to 12 years after diagnosis. According to the researchers, it is the most comprehensive study to date regarding the risk of complications in LADA.

Source: Karolinska Institutet

Categories : Medical Research & Technology Metabolic DisordersTags :

‘We Will Rock You’: The Special Cells that Secrete Insulin to Music

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Freddie Mercury performing with Queen in 1977. Source: Wikimedia Commons

Music has often been touted as a soothing treatment to aid healing. Now, researchers at ETH Zurich in Basel have come up with another medical approach. They have developed a novel method to get music to make specially designed cells secrete insulin. They found that this works especially well with the bass rhythm “We Will Rock You,” a global hit by British rock band, Queen.

Diabetics depend on an external supply of insulin via injection or pump. Researchers led by Martin Fussenegger from the Department of Biosystems Science and Engineering at ETH Zurich in Basel want to make the lives of these people easier and are looking for solutions to produce and administer insulin directly in the body. Any alternatives must be able to release insulin in controlled quantities on command.

One such solution the scientists are pursuing is enclosing insulin-producing designer cells in capsules that can be implanted in the body. To be able to control from the outside when and how much insulin the cells release into the blood, researchers have studied and applied different triggers in recent years: light, temperature and electric fields.

Equipping cells to receive sound waves

To make the insulin-producing cells receptive to sound waves, the researchers used a protein from the bacterium E. coli. Such proteins respond to mechanical stimuli and are common in animals and bacteria. The protein is located in the membrane of the bacterium and regulates the influx of calcium ions into the cell interior. The researchers incorporated the blueprint of this bacterial ion channel into human insulin-producing cells, letting these cells create the ion channel themselves and embed it in their membrane.

As the scientists have been able to show, the channel in these cells opens in response to sound, allowing positively charged calcium ions to flow into the cell. This leads to a charge reversal in the cell membrane, which in turn causes the tiny insulin-filled vesicles inside the cell to fuse with the cell membrane and release the insulin to the outside.

Turn up the bass

In cell cultures, the researchers first determined which frequencies and volume levels activated the ion channels most strongly. They found that volume levels around 60 decibels (dB) and bass frequencies of 50 hertz were the most effective in triggering the ion channels. To trigger maximum insulin release, the sound or the music had to continue for a minimum of three seconds and pause for a maximum of five seconds. If the intervals were too far apart, substantially less insulin was released.

Finally, the researchers looked into which music genres caused the strongest insulin response at a volume of 85dB. Rock music with booming bass like the song “We Will Rock You,” from Queen, came out on top, followed by the soundtrack to the action movie The Avengers. The insulin response to classical music and guitar music was rather weak by comparison.

“We Will Rock You” triggered roughly 70% of the insulin response within five minutes, and all of it within 15 minutes. This is comparable to the natural glucose-induced insulin response of healthy individuals, Fussenegger says.

Sound source must be directly above the implant

To test the system as a whole, the researchers implanted the insulin-producing cells into mice and placed the animals so that their bellies were directly on the loudspeaker. This was the only way the researchers could observe an insulin response. If, however, the animals were able to move freely in a “mouse disco,” the music failed to trigger insulin release.

“Our designer cells release insulin only when the sound source with the right sound is played directly on the skin above the implant,” Fussenegger explains. The release of the hormone was not triggered by ambient noise such as aircraft noise, lawnmowers, fire brigade sirens or conversations.

Ambient noise won’t do

As far as he can tell from tests on cell cultures and mice, Fussenegger sees little risk that the implanted cells in humans would release insulin constantly and at the slightest noise.

Another safety buffer is that insulin depots need four hours to fully replenish after they have been depleted. So even if the cells were exposed to sound at hourly intervals, they would not be able to release a full load of insulin each time and thereby cause life-threatening hypoglycaemia. “It could, however, cover the typical needs of a diabetes patient who eats three meals a day,” Fussenegger says. He explains that insulin remains in the vesicles for a long time, even if a person doesn’t eat for more than four hours. “There’s no depletion or unintentional discharge taking place.”

As a proof of concept only, clinical application is a long way off, but it shows that genetic networks can be controlled by mechanical stimuli such as sound waves. Whether this principle will ever be put to practical use depends on whether a pharmaceutical company is interested in doing so. It could, after all, be applied broadly: the system works not only with insulin, but with any protein that lends itself to therapeutic use.

Source: ETH Zurich

Categories : Ageing Metabolic DisordersTags :

In Animal Studies, Metformin Extends Lifespan

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Researchers have discovered that the common antidiabetic drug metformin not only lowers blood sugar levels but has revealed to extend lifespan in C. Elegans, an animal model that shares similar metabolic systems with humans and are often used to model human diseases.

This study, led by investigators at Massachusetts General Hospital (MGH), reveals that metformin promotes longevity by stimulating the body’s production of ether lipids, a major structural component of cell membranes.

The findings, which are published in eLife, suggest that boosting production of ether lipids in humans may support healthy aging and reduce the impact of aging-related diseases.

To identify the genes required to enable lifespan extension in response to metformin and its sister drug phenformin (drugs called biguanides), the scientists silenced individual genes in the roundworm Caenorhabditis elegans (which shares over 80% of its proteins with humans and has an average lifespan of about two weeks) and examined what happens to the altered worms after exposure to the medications.

The experiments reveal that genes that increase production of ether lipids are required to extend lifespan in response to the biguanides. Inactivation of the genes that encode for these enzymes completely prevented the longevity-promoting effects of biguanides. Importantly, inactivation of these genes prevented lifespan extension in a variety of situations that are also known to promote longevity, including dietary restriction.

The team also found that increasing ether lipid synthesis alone (by overexpressing a single, key ether lipid biosynthetic enzyme called fard-1) was sufficient to extend C. elegans’ lifespan, orchestrating a metabolic stress defense response through a factor called SKN-1, which is the worm counterpart to the mammalian protein Nrf. This response altered metabolism to promote a longer lifespan.

“Our study implicates promotion of ether lipid biosynthesis as a novel therapeutic target to promote healthy aging. This suggests that dietary or pharmacologic intervention to promote ether lipid synthesis might one day represent a strategy to treat aging and aging-related diseases,” says senior author Alexander A. Soukas, MD, PhD, an Associate Professor at Harvard Medical School.

“Because our studies focused solely on interventions in C. elegans, further studies in mammalian models (such as human cells and mice), epidemiological observation, and rigorous clinical trials are required to determine the viability of promoting ether lipid synthesis to promote human health-span and lifespan.”

Source: Massachusetts General Hospital

Categories : Cardiovascular Disease Metabolic DisordersTags :

Semaglutide Also Cuts Cardiovascular Risk, Could Change Cardiology Practice

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By HualinXMN – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=133759262

According to results from the SELECT trial run by Novo Nordisk, semaglutide dramatically reduces the risk of major adverse cardiovascular events (MACEs) in addition to its obesity benefits. This is bolstered by the results of another trial, STEP-1, which also suggested significant reduction in future cardiovascular events. These results have captured the attention of researchers, who commented in Nature that they could change the practice of cardiology.

Semaglutide, sold in the US for the treatment of both obesity (Wegovy) and diabetes (Ozempic), is an agonist for glucagon-like peptide 1 (GLP-1), a hormone associated with appetite.

”It’s hard to think of other [drugs], apart from statins, that have shown such a profound effect,” says Martha Gulati, director of preventive cardiology at Cedars-Sinai Medical Center in Los Angeles, USA.

It was expected that semaglutide would have cardiovascular benefits through promoting weight loss, but evidence shows that drugs mimicking GLP-1 can improve fatty-acid metabolism and reduce inflammation, for example, says Gulati. “This is what’s so fascinating about these drugs. They work on the brain, the pancreas, the cardiovascular system, the gastrointestinal tract … There’s more to them than simply weight loss.”

Recent studies have been encouraging in terms of semaglutide’s benefits for reducing cardiovascular disease risk. Earlier this month, Novo Nordisk announced the headline results from the SELECT cardiovascular outcomes trial. The double-blinded trial compared subcutaneous once-weekly semaglutide 2.4mg with placebo as an adjunct to standard of care for prevention of MACEs over a period of up to five years. The trial enrolled 17 604 adults aged 45 years or older with overweight or obesity and established cardiovascular disease (CVD) with no prior history of diabetes.

The trial showed 20% reduction in MACEs for people treated with semaglutide 2.4mg compared to placebo. The primary endpoint was a composite outcome of the first occurrence of MACE cardiovascular death, non-fatal myocardial infarction or non-fatal stroke. All three of these components contributed to the MACE reduction. 1270 first MACEs were accrued.

Expanding GLP-1 analogues to cardiovascular disease prevention may not be without challenges, as the European Medicines Agency opened investigations into semaglutide and liraglutide over reports of suicidal thoughts and self-harm.

A separate study based on the STEP 1 trial data found that 93 million adults in the US could benefit from semaglutide, from a combination of weight loss and reduced cardiovascular benefits. They estimate a reduction in relative risk of 18% with the drug.