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Aerobic exercise can help fight liver diseases

he Mfn-2 protein would regulate the curve of the mitochondrial membrane in promoting the oxidation of fat in a specific population of mitochondria, through its interaction and ability to form specific domains with membrane phospholipids.

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Aerobic exercise could help fight the non-alcoholic fatty liver disease, the most common liver disease worldwide: it affects nearly 24% of the global population and it usually causes a certain stigma among the affected people.

This is according to a study – “Mitofusin-2 induced by exercise modifies lipid droplet-mitochondria communication, promoting fatty acid oxidation in male mice with NAFLD” that appeared in the journal Metabolism. The study was led by Professor María Isabel Heràndez-Alvarez, in collaboration with Rodrigo Troncoso, and Víctor Cortés.  

When the liver accumulates large amounts of fat

One of the features of the fatty liver disease or non-alcoholic steatohepatitis (NAFLD) is the large concentration of lipid droplets (LD) that accumulate in the liver cells. “Our findings reveal that aerobic exercise, that is, moderate physical activity over time, helps metabolize the fats because it reduces the size of lipid droplets, and therefore, the severity of the disease”, notes the author. 

“Therefore, the energy demands induced by the exercise determine regulated changes in physical and functional relationships between fat droplets and mitochondria, the cell organelles that provide energy for the metabolism.”

This interaction may take place in a specific population of mitochondria known as peridroplet mitochondria (PDM). “As a result, there is a higher oxidation of lipids in this specific population of mitochondria, a process that helps prevent the progress of the disease”.

Discovering a previously unknown connection

“The interaction between the lipid droplets (LD) and the mitochondria is functionally important for the homeostasis of the fat metabolism. Exercise improves fatty liver disease, but to date, it was unknown whether the disease had a direct impact on the interactions between hepatic LDs and mitochondria,” noted María Isabel Hernàndez-Alvarez, Ramón y Cajal postdoctoral researcher at the UB’s Department of Biochemistry and Molecular Biomedicine.

The study also stresses that mitofusin 2 (Mfn-2) — a protein located in the external membrane of mitochondria — plays a decisive role in this process, since it modifies the communication between lipid droplets and the specific population of mitochondria.

“We found a decrease in the content related to saturated fatty acids in the hepatic mitochondrial membranes of animals that had done physical activity. This suggests that membrane fluidity increases in the mitochondria,” noted the researcher. “In the case of the mice without the Mfn-2 gene, exposed to physical activity, we did not observe changes in the saturation and the metabolism of fatty acids. These results show that the Mfn-2 protein takes part in the regulation of the composition of fatty acids of the mitochondrial membranes in response to exercise”.

According to the authors, the Mfn-2 protein would regulate the curve of the mitochondrial membrane in promoting the oxidation of fat in a specific population of mitochondria, through its interaction and ability to form specific domains with membrane phospholipids.

The study is a step forward to boosting research on mediators and molecular mechanisms that could promote new strategies to prevent the progression of NAFLD. “Considering the Mfn-2 functions in mitochondrial morphology and in the liver, the therapeutic manipulations of the levels and the activity of Mfn-2 could contribute to the improvement of the NAFLD-related inflammation and the fibrosis”, concluded the researcher.

A registered nurse, “Ching” – as many fondly call Rachelle Grace – believes that a holistic approach to health and wellness is what everyone should aim for. She is, therefore, always on the lookout for what could help achieve this. And yes, she shares them openly, believing “knowledge about what works won’t be much use if it’s not known by as many as possible”.

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Young vapers perform worse in exercise testing

On average, the group of young vapers had lower ‘peak exercise capacity’ (186 watts) than the group who did not vape or smoke (226 watts) but similar capacity to the group of smokers (182 watts). This is a measure of the maximum amount of physical exertion that a person can achieve.

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Young people who vape perform worse than non-vapers in tests designed to measure their capacity for exercise, according to a study presented at the European Respiratory Society (ERS) Congress in Vienna, Austria. The research also showed that the performance of young vapers was similar to that of young smokers.

The study adds to growing evidence that long-term use of vaping is harmful and challenges the idea that vaping could be a healthier alternative to smoking.

The research was presented by Dr Azmy Faisal, senior lecturer in cardiorespiratory physiology in the department of sport and exercise sciences at Manchester Metropolitan University, UK. He said: “Previous research has shown that vaping is linked to lung inflammation and damage, and harmful changes to the blood vessels. Although, some research suggests that vaping could be used to cut back or quit smoking, we don’t yet know what longer-term vaping use does to our bodies.”

The study included 60 people in their 20s who all had normal lung function according to spirometry testing. Twenty were non-smokers and non-vapers, 20 had been vaping for at least two years and 20 had been smoking for at least two years.

Each person took part in an incremental exercise test on a static bike. This is the gold-standard for testing physical ability and how well a person copes with exercise, looking at their heart, lungs, and muscles’ responses at harder and harder levels until they reach their maximum. They were also given blood tests and an ultrasound scan to analyse how well their arteries were functioning.

On average, the group of young vapers had lower ‘peak exercise capacity’ (186 watts) than the group who did not vape or smoke (226 watts) but similar capacity to the group of smokers (182 watts). This is a measure of the maximum amount of physical exertion that a person can achieve. At peak exercise, vapers and smokers were also less able to consume oxygen on average (2.7 litres per minute and 2.6 litres per minute) compared to the non-smoking non-vaping groups (3 litres per minute).

Both vapers and smokers showed signs that their blood vessels were not working as well as the non-smoking and non-vaping group, according to the blood tests and ultrasound scans. The smokers and the vapers were more out of breath, experienced intense leg fatigue and had higher levels of lactate in their blood, a sign of muscle fatigue, even before they reached their maximum level of exercise.

Dr Faisal said: “In this study, we looked at a group of young people with no apparent signs of lung damage. Among the people who had been vaping or smoking for at least two years, we saw important differences in how well they coped with exercise. The smokers and the vapers had measurably excess breathing while using the exercise bikes. They found it harder to breath, their muscles became more fatigued, and they were less fit overall. In this regard, our research indicated that vaping is no better than smoking.”

Dr Filippos Filippidis is Chair of the ERS Tobacco Control Committee, a reader in public health at Imperial College London and was not involved in the research. He said: “Vapes are being sold cheaply and in a variety of flavours to appeal to young people. As a result, we’re seeing more and more young people take up the habit without knowing what the long-term consequences could be to their health.

“Although it’s always a challenge to know if the associations we find in these studies are causal or a result of some other systematic differences between groups, people who vape need to be aware that using these products could make them less fit and able to take part in exercise. Doctors and policymakers also need to know about the risks of vaping, and we should be doing all we can to support children and young people to avoid or quit vaping.”

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Some adverse pregnancy outcomes may increase risk of heart disease later in life

A self-reported history of gestational hypertension was associated with cardiovascular disease. Women with preeclampsia or all three adverse pregnancy outcomes also had a numerically higher prevalence of heart disease, but it did not meet the standards of statistical significance. No association was found between gestational diabetes and heart disease.

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Pregnancy-related hypertension has already been proven to lead to a number of negative health outcomes later in life, including more bothersome menopause symptoms like hot flashes, the risk of dementia, kidney problems, and stroke. A new study suggests it can also lead to cardiovascular disease during menopause. Results of the study were presented at the 2024 Annual Meeting of The Menopause Society in Chicago, USA.

In the new study involving nearly 400 women with a mean age of 81.6 years, researchers sought to assess the association between a self-reported history of preeclampsia or eclampsia, gestational hypertension, and gestational diabetes with cardiovascular outcomes in postmenopausal women.

What they found is that a self-reported history of gestational hypertension was associated with cardiovascular disease. Women with preeclampsia or all three adverse pregnancy outcomes also had a numerically higher prevalence of heart disease, but it did not meet the standards of statistical significance. No association was found between gestational diabetes and heart disease.

“Future research based on a larger sample size is needed to better understand the role adverse pregnancy outcomes may have in cardiovascular disease development and risk stratification,” says Marie Tan, lead author from Drexel University College of Medicine in Philadelphia.

More detailed results will be discussed at the 2024 Annual Meeting of The Menopause Society as part of the presentation entitled “The association between adverse pregnancy outcomes and cardiovascular disease in menopausal women: results from a cross-sectional analysis.”

“Cardiovascular disease is the number one cause of mortality in women and it’s important to study any new risk factors” says Dr. Stephanie Faubion, medical director for The Menopause Society. “Although future research is still needed, studies like this are important and remind us to thoroughly discuss a patient’s health history, including any complications or adverse outcomes during pregnancy.”

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Babies born to women consuming a high fat, sugary diet at greater risk of cardiovascular disease and diabetes in later life

Consuming a high-fat, sugary diet during pregnancy also increases the likelihood of the unborn baby becoming insulin resistant in adulthood, potentially triggering diabetes and causing cardiovascular disease. This is despite babies being a normal weight at birth.

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Babies born to pregnant women with obesity are more likely to develop heart problems and diabetes as adults due to fetal damage caused by the high-fat, high-energy diet of their mother.

That’s the groundbreaking finding from a new study published in the Journal of Physiology that shows for the first time that maternal obesity alters a critical thyroid hormone in the fetal heart, disrupting its development.

Consuming a high-fat, sugary diet during pregnancy also increases the likelihood of the unborn baby becoming insulin resistant in adulthood, potentially triggering diabetes and causing cardiovascular disease. This is despite babies being a normal weight at birth.

University of South Australia researchers identified the link by analysing tissue samples from the fetuses of pregnant baboons fed a high-fat, high-energy diet in a biomedical research institute in the United States. They then compared this to fetuses from baboons on a control diet.

Lead author, University of South Australia PhD candidate Melanie Bertossa, says the findings are significant because they demonstrate a clear link between an unhealthy diet high in saturated fats and sugar, and poor cardiovascular health.

“There has been a long-standing debate as to whether high-fat diets induce a hyper- or hypothyroid state in the fetal heart. Our evidence points to the latter,” Bertossa says.

“We found that a maternal high-fat, high-energy diet reduced concentrations of the active thyroid hormone T3, which acts like a switch around late gestation, telling the fetal heart to start preparing for life after birth. Without this signal, the fetal heart develops differently.”

Bertossa says that diets high in fat and sugar can alter the molecular pathways involved in insulin signalling and critical proteins involved in glucose uptake in the fetal heart. This increases the risk of cardiac insulin resistance, often leading to diabetes in adulthood.

“You’re born with all the heart cells you will ever have. The heart doesn’t make enough new heart muscle cells after birth to repair any damage, so changes that negatively impact these cells before birth could persist for a lifetime.

“These permanent changes could cause a further decline in heart health once children reach adolescence and adulthood when the heart starts to age.”

Senior author, UniSA Professor of Physiology Janna Morrison, says the study demonstrates the importance of good maternal nutrition in the leadup to pregnancy, not only for the mother’s sake but also for the health of the baby.

“Poor cardiac outcomes were seen in babies that had a normal birth weight – a sign that should guide future clinical practice,” Prof Morrison says.

“Cardiometabolic health screening should be performed on all babies born from these types of pregnancies, not just those born too small or too large, with the goal being to detect heart disease risks earlier.”

Prof Morrison says that if rising rates of high-fat sugary diets are not addressed, more people will develop health complications such as diabetes and cardiovascular disease, which could result in shorter life spans in the decades ahead.

“Hopefully, with the knowledge we have now about the negative health impacts of obesity, there is potential to change this trajectory.”

The researchers are currently undertaking long-term studies of babies born to women on high- fat high-energy diets to track their health over decades.

Maternal high-fat high-energy diet alters metabolic factors in the non-human primate fetal heart” is published in the Journal of Physiology and authored by researchers from the University of South Australia, University of Wyoming and Texas Biomedical Health Institute.

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