New favorite—smart electric wheel drive tractor: realizes efficient drive with ingenious structure and intelligent control

ENGINEERING

Electric tractors are intended to be used in the field instead of traditional fuel tractors and can be used in greenhouse planting, indoor farming, mountainous operations, and other special operating scenarios. Unlike traditional fuel tractors, electric tractors have no exhaust emissions, rapid drive system response, flexible power output, or other advantages. These scenarios require electric tractors to be able to adapt to complex drive and operating environments, putting higher requirements on the design of electric tractors and their control systems. Therefore, improving the operating efficiency of electric tractors and giving full play to their traction capacity have become urgent breakthrough issues.

Specifically, existing tractors suffer from reduced traction efficiency, low fuel efficiency, and high greenhouse gas emissions when ploughing on complex field surfaces. These issues are manifested as follows: high wheel slip due to the inability to achieve differential torque distribution between the left and right drive wheels, unreasonable front- and rear-axle load distribution due to the inability to continuously and intelligently regulate the fixed counterweight, and low tillage quality due to the inability of the electro-hydraulic suspension system to balance the agronomic requirements of the operation with the traction performance of the unit.

Therefore, in response to the problems of excessive greenhouse-gas and particulate emissions and the low traction efficiency of conventional diesel tractors in the field, a purely electric wheel-side drive tractor was studied, including an electric motor drive system, a battery ballast system, and an electro-hydraulic suspension system. This paper develops a dynamics model of an electric tractor-ploughing unit under complex soil conditions, leading to the proposal of an active control method for drive wheel torque and a joint control method for the traction force of the suspension system and the front- and rear-axle loads of a tractor. Finally, the tractor is prototyped and assembled, and ploughing tests are carried out. The ploughing results show that the active torque-distribution control method proposed in this study reduces the tractor slip by 14.83% and increases the traction efficiency by 10.28% compared with the average torque-distribution mode. Compared with the conventional traction control mode, the joint control method for traction and ballast proposed in this paper results in a 3.7% increase in traction efficiency, a 15.05% decrease in slip, and a 4.9% reduction in total drive motor energy consumption.

The main contributions of this work are as follows:

(1) A new overall configuration for an electric tractor, composed of a wheel-side motor independent drive system, a battery ballast system, and a direct-drive electro-hydraulic suspension system, is proposed to provide an intelligent carrier for the key system and the whole machine in order to realize high-efficiency control.

(2) To overcome the problems of longitudinal wheel slip, rearward shift of the center of gravity of the unit, and insufficient traction power of the whole tractor during field operation, a nine-degrees-of-freedom (9-DOFs) electric tractor dynamics model is constructed; moreover, an active control method for the driving wheel torque and a joint control method for the traction force and the front- and rear-axle loads are researched.

(3) This study will help to improve the operation quality and traction efficiency of electric tractors in complex soil conditions.

The paper titled “Reducing Operation Emissions and Improving Work Efficiency Using a Pure Electric Wheel Drive Tractor” was published in Engineering. Chang-kai Wen is listed as the first author, with Bin Xie and Zhi-jun Meng as the co-corresponding authors. The study also received guidance from Mr. Chun-jiang Zhao, who is an academician of the Chinese Academy of Engineering. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.01.026. For more information about the Engineering, follow us on Twitter (https://twitter.com/EngineeringJrnl) & like us on Facebook (https://www.facebook.com/EngineeringJrnl).

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JOURNAL

Engineering

DOI

10.1016/j.eng.2024.01.026 

ARTICLE TITLE

Reducing Operation Emissions and Improving Work Efficiency Using a Pure Electric Wheel Drive Tractor

 

Breast cancer rates rising among Canadian women in their 20s, 30s and 40s

Researchers highlights need for immediate shift in public health policy as early detection is key to reducing breast cancer death and complications

UNIVERSITY OF OTTAWA

 

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"BREAST CANCER IN YOUNGER WOMEN TENDS TO BE DIAGNOSED AT LATER STAGES AND IS OFTEN MORE AGGRESSIVE," SAID LEAD AUTHOR DR. JEAN SEELY, Head of Breast Imaging AT THE OTTAWA HOSPITAL AND Professor IN THE DEPARTMENT OF RADIOLOGY AT THE UNIVERSITY OF OTTAWA. "IT’S ALARMING TO SEE RISING RATES AMONG WOMEN IN THEIR TWENTIES AND THIRTIES BECAUSE THEY ARE NOT REGULARLY SCREENED FOR BREAST CANCER.”

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CREDIT: UNIVERSITY OF OTTAWA/THE OTTAWA HOSPITAL

Rates of breast cancer in women under the age of 50 are rising in Canada according to a study which showed an increase in breast cancer diagnoses among females in their Twenties, Thirties, and Forties.

Led by Dr. Jean Seely, this study published in the Canadian Association of Radiologists Journal reviewed breast cancer cases over 35 years to shed light on trends in breast cancer detection in Canada.

"Breast cancer in younger women tends to be diagnosed at later stages and is often more aggressive," said Dr. Seely, Head of Breast Imaging at The Ottawa Hospital and Professor in the Department of Radiology at the University of Ottawa. "It’s alarming to see rising rates among women in their Twenties and Thirties because they are not regularly screened for breast cancer.”

Risk increases with age

Using data from the National Cancer Incidence Reporting System (1984-1991) and the Canadian Cancer Registry (1992-2019) at Statistics Canada, the research team, which included Larry Ellison from Statistics Canada and Dr. Anna Wilkinson, an Associate Professor in the Faculty of Medicine, looked at all women aged 20 to 54 who were diagnosed with breast cancer.

Their findings included:

• For women in their Twenties, there were 3.9 cases per 100,000 people between 1984 and 1988, compared to 5.7 cases per 100,000 between 2015 and 2019 for a 45.5% increase.
• For women in their Thirties, there were 37.7 cases per 100,000 people between 1984 and 1988, compared to 42.4 cases per 100,000 between 2015 and 2019 for a 12.5% increase.
• For women in their Forties, there were 127.8 cases per 100,000 people between 1984 and 1988, compared to 139.4 cases per 100,000 between 2015 and 2019 for a 9.1% increase.

The study’s results show the importance of targeting younger women in breast cancer awareness campaigns and screening programs. Most public health efforts focus on women over 50, but these findings suggest that younger women are increasingly at risk and may benefit from earlier and more frequent screenings.

Personal experience

Chelsea Bland is one of those women.

Hearing about a death from breast cancer at age 33 led Chelsea – then 28 – to conduct her own self-examination, where she discovered a lump. This led to screenings which ultimately led to a breast cancer diagnosis and subsequent treatment. While she is two years cancer free, she remains on hormone therapy today. The entire experience led Chelsea to help establish a local group that provides peer support for younger women – the average ages range between 28 to 40.

“I hope that by bringing awareness to this study it makes people think twice about saying that being in your twenties, thirties and forties is too young to have breast cancer. In my support group, I have heard the same story over and over again,” Chelsea says. “Young women are not being taken seriously after they find a lump because they are told they are too young for breast cancer. This has ultimately led to delays in being diagnosed and being diagnosed at a more advanced stage. We are not too young for this and this is happening to women who do not have any high-risk genetic markers for breast cancer, myself included.”

Improving awareness

The investigators say more research is needed to understand the root cause of rising breast cancer rates among younger women, information that could be used to develop targeted intervention strategies.

“We’re calling for increased awareness among health-care professionals and the public regarding the rising incidence of breast cancer in younger women,” said Dr. Seely, who alongside Dr. Wilkinson have long documented the benefits of early detection with screening for women in their forties. “We need to adapt our strategies and policies to reflect these changing trends, ensuring that all women, regardless of age, have access to the information and resources they need to detect and combat this disease.”

“Young women are not being taken seriously after they find a lump because they are told they are too young for breast cancer," says Chelsea Bland, who was diagnosed with breast cancer. "This has ultimately led to delays in being diagnosed and being diagnosed at a more advanced stage. We are not too young for this and this is happening to women who do not have any high-risk genetic markers for breast cancer, myself included.”

CREDIT

University of Ottawa

JOURNAL

Canadian Association of Radiologists Journal

DOI

10.1177/08465371241246422 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Incidence of Breast Cancer in Younger Women – A Canadian Trend Analysis

ARTICLE PUBLICATION DATE

26-Apr-2024

 

UNC Charlotte bioinformatics professor discovers surprising evolutionary pattern in landmark yeast study

UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE

 

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YEAST COLONIES (ARTIFICIALLY COLORED)

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CREDIT: UNC CHARLOTTE

University of North Carolina at Charlotte Assistant Professor of Bioinformatics Abigail Leavitt LaBella has co-led an ambitious research study — published this week in the widely influential journal Science — that reports intriguing findings made through innovative artificial intelligence analysis about yeasts, the small fungi that are key contributors to biotechnology, food production and human health. The findings challenge accepted frameworks within which yeast evolution is studied and provide access to an incredibly rich yeast analysis dataset that could have major implications for future evolutionary biology and bioinformatics research.

LaBella, who joined UNC Charlotte’s Department of Bioinformatics in the College of Computing and Informatics as an assistant professor and researcher at the North Carolina Research Campus in 2022, conducted the study with co-lead author Dana A. Opulente of Villanova University. They collaborated with fellow researchers from Vanderbilt University and the University of Wisconsin at Madison, along with colleagues from research institutions across the globe.

This is the flagship study of the Y1000+ Project, a massive inter-institutional yeast genome sequencing and phenotyping endeavor that LaBella joined as a postdoctoral researcher at Vanderbilt University. 

“Yeasts are single-celled fungi that play critical roles in our everyday lives. They make bread and beer, are used in the production of medicine, can cause infection, and as close relatives to animals have helped us learn about how cancer works,” said LaBella. “We wanted to know how these small fungi have evolved to have such an incredible range of functions and features. With the characterization of over one thousand yeasts, we found that yeasts do not fit the adage ‘jack of all trades, master of none.’” 

This study contributes to basic understanding of how the microbes change over time while generating more than 900 new genome sequences for yeasts — many of which could be leveraged in biofungal fields such as agricultural pest control, drug development and biofuels production.  

LaBella and her co-authors — through an artificial intelligence-assisted, machine-learning analysis of the Y1000+ Project's dataset comprising 1,154 strains of the ancient, single-cell yeast Saccaromycotina — attempted to answer an important question. That is: Why do some yeasts eat (or metabolize) only a few types of carbon for energy while others can eat more than a dozen? 

The total number of carbon sources used by a yeast for energy is known in ecological terms as its carbon niche-breadth. Humans also vary in their carbon niche breadth — for example, some people can metabolize lactose while others cannot. 

Evolutionary biology research has supported two key overarching paradigms about niche breadth, the phenomenon explaining why some yeast organisms (“specialists”) evolve to be able to metabolize only a small number of carbon forms as fuel while others (“generalists”) evolve to be able to consume and grow on a broad variety of carbon forms. One of these paradigms illustrates that being a generalist comes with certain trade-offs compared to being a specialist. Notably, in the latter case, the ability to process a wide range of carbon forms comes at the expense of the yeast’s capacity to process and grow on each carbon form efficiently. The second is that these yeast specialists and generalists evolve to fit either profile due to the combined effects of different intrinsic traits of their respective genomes and different extrinsic influences based on the varying environments in which yeast organisms exist.

LaBella and her colleagues found ample evidence supporting the idea that there are identifiable, intrinsic genetic differences in yeast specialists versus generalists, specifically that generalists tend to have a larger total number of genes than specialists. For example, they found that generalists are more likely to be able to synthesize carnitine, a molecule that is involved in energy production and often sold as an exercise supplement.

But unexpectedly, their research found very limited evidence for the anticipated evolutionary trade-off of a yeast’s ability to process many forms of carbon coming at the expense of its ability to do so efficiently and grow accordingly, and vice versa.

“We saw that the yeasts that could grow on lots of carbon substrates are actually very good growers,” said LaBella. “That was a very surprising finding to us.”

While the findings of this specific experiment and the innovative machine-learning mechanisms used in its analysis could have major implications for bioinformatics, ecology, metabolics and evolutionary biology, the publishing of this study means that the Y1000+ Project’s massive compendium of yeast data is now available for scholars worldwide to use as a starting point to amplify their own yeast research.

“This dataset will be a huge resource going forward,” said LaBella.

  

Abigail Leavitt LaBella

CREDIT

UNC Charlotte

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JOURNAL

Science

DOI

10.1000/xyz123 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

Genomic factors shape carbon and nitrogen metabolic niche breadth across Saccharomycotina yeasts

ARTICLE PUBLICATION DATE

25-Apr-2024

COI STATEMENT

JLS was a scientific adviser for WittGen Biotechnologies and is an adviser for ForensisGroup, Inc. AR is a scientific consultant for LifeMine Therapeutics, Inc. The other authors declare no other competing interests.

 

The end of the quantum tunnel

UNIVERSITEIT VAN AMSTERDAM

Quantum physics – easy and hard

In the quantum world, processes can be separated into two distinct classes. One class, that of the so-called ‘perturbative’ phenomena, is relatively easy to detect, both in an experiment and in a mathematical computation. Examples are plentiful: the light that atoms emit, the energy that solar cells produce, the states of qubits in a quantum computer. These quantum phenomena depend on Planck’s constant, the fundamental constant of nature that determines how the quantum world differs from our large-scale world, but in a simple way. Despite the ridiculous smallness of this constant – expressed in everyday units of kilograms, metres and seconds it takes a value that starts at the 34th decimal place after the comma – the fact that Planck’s constant is not exactly zero is enough to compute such quantum effects.

Then, there are the ‘nonperturbative’ phenomena. One of the best known is radioactive decay: a process where due to quantum effects, elementary particles can escape the attractive force that ties them to atomic nuclei. If the world were ‘classical’ – that is, if Planck’s constant were exactly zero – this attractive force would be impossible to overcome. In the quantum world, decay does occur, but still only occasionally; a single uranium atom, for example, would on average take over four billion years to decay. The collective name for such rare quantum events is ‘tunneling’: for the particle to escape, it has to ‘dig a tunnel’ through the energy barrier that keeps it tied to the nucleus. A tunnel that can take billions of years to dig, and makes The Shawshank Redemption look like child’s play.

Mathematics to the rescue

Mathematically, nonperturbative quantum effects are much more difficult to describe than their perturbative cousins. Still, over the century that quantum mechanics has existed, physicists have found many ways to deal with these effects, and to describe and predict them accurately. “Still, in this century-old problem, there was work left to be done”, says Alexander van Spaendonck, one of the authors of the new publication. “The descriptions of tunneling phenomena in quantum mechanics needed further unification – a framework in which all such phenomena could be described and investigated using a single mathematical structure.”

Surprisingly, such a structure was found in 40-year-old mathematics. In the 1980s, French mathematician Jean Écalle had set up a framework that he dubbed resurgence, and that had precisely this goal: giving structure to nonperturbative phenomena. So why did it take 40 years for the natural combination of Écalle’s formalism and the application to tunneling phenomena to be taken to their logical conclusion? Marcel Vonk, the other author of the publication, explains: “Écalle’s original papers were lengthy – over 1000 pages all combined – highly technical, and only published in French. As a result, it took until the mid-2000s before a significant number of physicists started getting familiar with this ‘toolbox’ of resurgence. Originally, it was mostly applied to simple ‘toy models’, but of course the tools were also tried on real-life quantum mechanics. Our work takes these developments to their logical conclusion”.

Beautiful structure

That conclusion is that one of the tools in Écalle’s toolbox, that of a ‘transseries’, is perfectly suited to describe tunneling phenomena in essentially any quantum mechanics problem, and does so always in the same way. By spelling out the mathematical details, the authors found that it became possible not only to unify all tunneling phenomena into a single mathematical object, but also to describe certain ‘jumps’ in how big the role of these phenomena is – an effect known as Stokes’ phenomenon.

Van Spaendonck: “Using our description Stokes’ phenomenon, we were able to show that certain ambiguities that had plagued the ‘classical’ methods of computing nonperturbative effects – infinitely many, in fact – all dropped out in our method. The underlying structure turned out to be even more beautiful than we originally expected. The transseries that describes quantum tunneling turns out to split – or ‘factorize’ – in a surprising way: into a ‘minimal’ transseries that describes the basic tunneling phenomena that essentially exist in any quantum mechanics problem, and an object that we called the ‘median transseries’ that describes the more problem-specific details, and that depends for example on how symmetric a certain quantum setting is.”

With this mathematical structure completely clarified, the next question is of course where the new lessons can be applied and what physicists can learn from them. In the case of radioactivity, for example, some atoms are stable whereas others decay. In other physical models, the lists of stable and unstable particles may vary as one slightly changes the setup – a phenomenon known as ‘wall-crossing’. What the researchers have in mind next is to clarify this notion of wall-crossing using the same techniques. This difficult problem has again been studied by many groups in many different ways, but now a similar unifying structure might be just around the corner. There is certainly light at the end of the tunnel.

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JOURNAL

SciPost Physics

DOI

10.21468/SciPostPhys.16.4.103 

ARTICLE TITLE

Exact instanton transseries for quantum mechanics

 

Up in smoke: new study suggests it’s time to ditch long-held stereotypes about stoners

UNIVERSITY OF TORONTO

Stoners are not as lazy and unmotivated as stereotypes suggest, according to new U of T Scarborough research.

The study, published by the journal Social Psychological and Personality Science, surveyed chronic cannabis users to see what effect getting high has on their everyday lives. 

“There is a stereotype that chronic cannabis users are somehow lazy or unproductive,” says Michael Inzlicht, a professor in the Department of Psychology at U of T Scarborough who led the study. 

“We found that’s not the case — their behaviours might change a bit in the moment while they’re high, but our evidence shows they are not lazy or lacking motivation at all.” 

The researchers surveyed 260 chronic users (those who consume cannabis at least three times a week or more), who received regular messages through an app asking if they were high. The participants were then asked about their emotional state, levels of motivation, willingness to invest effort and self-regulation. 

Inzlicht says the most interesting finding relates to motivation. 

The researchers studied the participants’ willingness to exert effort in completing a task while high. They found participants were willing and motivated to exert the same amount of effort while high compared to when they are not.   

Past research has shown mixed results when it comes to chronic cannabis use and motivation. Inzlicht notes much of it relied on limited experimental designs that didn't account for differences between cannabis users and non-users, such as variations in personality, mental health, or use of other psychoactive substances. He says this study instead looked at chronic cannabis use while participants were actively high, while also accounting for these pre-existing differences.

 

Emotions, self-regulation and ‘weed hangover’     

 

The researchers found that getting high did lead to lower levels of self-regulation, which is an important trait for being able to accomplish tasks. They found that when chronic users are high it does impact certain behaviours linked to self-regulation, such as being more impulsive, less thoughtful and less orderly. 

“These things can detract someone from getting stuff done, but we didn’t find it made them less hard-working, responsible or able to focus,” says Inzlicht. 

They also found that chronic cannabis users experience a boost in positive emotions such as awe and gratitude, and a reduction in some negative emotions such as fear and anxiety while high. However, the researchers found those who get high a lot, on the higher end of chronic use, experience more negative emotions while high and while sober. 

The researchers found no evidence of “weed hangover,” that is, chronic users didn’t experience a decline in function (emotion or motivation) the day after being high. 

 

New frontier for cannabis research

 

Studying the effects of daily cannabis use was difficult in the past given its legal status, and most research tended to focus only on the negative side in an effort to curb use. Now that cannabis is legal in Canada, he says it’s much easier to study, and he expects there will be greater research focusing on the risks as well as the possible positive effects. 

“The cannabis literature, historically, tended to focus a lot on the negative medical consequences of chronic use,” says Inzlicht, who runs the Work and Play Lab, which does research on self-control, motivation and empathy as well as social media, digital device and recreational cannabis use. 

“Part of the motivation for this study is to take a neutral, clear-eyed approach to see how cannabis affects chronic users in their everyday lives.” 

Inzlicht says this study isn’t an endorsement of heavy cannabis use, adding there is plenty of research highlighting the risks associated with heavy use, especially among adolescents. 

Rather, he points to Statistics Canada data showing that nearly one in 10 adult Canadians are regular cannabis users, and they come from all walks of life. Cannabis is also the fourth most used recreational drug after caffeine, alcohol and tobacco. But despite its increased legal and social acceptance, relatively little is known about the everyday experiences of regular users.  

“Our data suggests that you can be hard-working, motivated and a chronic cannabis user at the same time.” 

 

The study received funding from the Social Sciences and Humanities Research Council of Canada. 

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JOURNAL

Social Psychological and Personality Science

DOI

10.1177/19485506241245744 

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Chronic Cannabis Use in Everyday Life: Emotional, Motivational, and Self-Regulatory Effects of Frequently Getting High

ARTICLE PUBLICATION DATE

23-Apr-2024

 

Researchers introduce new way to study, help prevent landslides

RIT Ph.D. student and professor co-author paper published in Nature Communications

ROCHESTER INSTITUTE OF TECHNOLOGY

Landslides are one of the most destructive natural disasters on the planet, causing billions of dollars of damage and devastating loss of life every year. By introducing a new paradigm for studying landslide shapes and failure types, a global team of researchers has provided help for those who work to predict landslides and risk evaluations.

Rochester Institute of Technology Ph.D. student Kamal Rana (imaging science) was a lead author on a paper recently published in Nature Communications announcing the research, along with co-author Nishant Malik, assistant professor in RIT’s School of Mathematics and Statistics. Kushanav Bhuyan, from the University of Padova and Machine Intelligence and Slope Stability Laboratory, was also a lead co-author.

Current predictive models rely on databases that do not generally include information on the type of failure of mapped landslides. By using the aerial view and elevation data of landslide sites combined with machine learning, the researchers were able to achieve 80-94 percent accuracy in identifying landslide movements in diverse locations around the world. Specifically, the study introduces a method of examining slides, flows, and fails, finding distinct patterns.

Researchers studied landslides around the world, like the 2008 disaster in Beichuan, China, to develop a new paradigm to understand their movements and failure types.

“Our algorithm is not predicting landslides,” explained Malik. “But the people who are in the business of predicting landslides need to know more information about them, like what caused them and what mechanisms they were.”

Various locations were studied, including Italy, the United States, Denmark, Turkey, and China. The wide array of countries helped confirm the strength of the findings, since they can be successfully utilized in diverse regions and climates.

“It was quite exhilarating when we saw the success numbers,” said Bhuyan. “We got the results, which are really good, but we need to be able to connect this to reality.”

The real-world application of this research has a personal impact for Rana, who is from the Himalayan region of India.

“I have seen so many cases when landslides have occurred,” said Rana. “The roads are blocked for two or three weeks. There is no communication from the cities to the villages. It blocks people from going to their jobs or students going to school.”

The hope is that this deeper understanding of failure movements will help those who work to predict deadly events and enhance the accuracy and reliability of hazard and risk assessment models, which will help save lives and reduce damage.

Along with Rana, Bhuyan, and Malik, co-authors of the paper include Joaquin V. Ferrer, Fabrice Cotton, and Ugur Ozturk from the University of Potsdam, and Filippo Catani from the University of Padova.

 

People with rare longevity mutation may also be protected from cardiovascular disease

Patients with growth hormone receptor deficiency, or Laron syndrome, appear to have lower than average risk factors for cardiovascular disease, according to a new study.

UNIVERSITY OF SOUTHERN CALIFORNIA

 

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JAIME GUEVARA-AGUIRRE (BACK LEFT), VALTER LONGO (BACK RIGHT), AND SEVERAL OF THE LARON STUDY PARTICIPANTS AT THE USC LEONARD DAVIS SCHOOL OF GERONTOLOGY IN LOS ANGELES.

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CREDIT: COURTESY JAIME GUEVARA-AGUIRRE AND VALTER LONGO

A new study highlights possible cardiovascular health advantages in individuals with a rare condition known as growth hormone receptor deficiency (GHRD), also called Laron syndrome.

GHRD, which is characterized by the body’s impaired ability to use its own growth hormone and results in stunted growth, has been linked in mice to a record 40% longevity extension and lower risks for various age-related diseases. However, the risk of cardiovascular disease in individuals with GHRD has remained unclear until now, leading to the speculation that in people, this mouse longevity mutation may actually increase cardiovascular disease.

The study, appearing in Med on April 26, 2024, is the latest product of an international  collaboration spanning nearly 20 years between Valter Longo, professor of gerontology at the USC Leonard Davis School of Gerontology, and endocrinologist Jaime Guevara-Aguirre of the Universidad San Francisco de Quito, Ecuador.

Over the past two decades, Longo, Guevara-Aguirre and colleagues have examined the health and aging of people with the gene mutation that causes GHRD. This rare mutation – found in just 400 to 500 people worldwide – was identified in a group of Ecuadorians whose ancestors had fled Spain during the Inquisition more than three centuries ago. The mutation leaves them with ineffective growth hormone receptors and results in a type of dwarfism. 

The team’s previous research has indicated that while GHRD/Laron syndrome reduces growth, it also appears to reduce the risk of several age-related diseases. Although the Ecuadorians with GHRD have a higher rate of obesity, they have a very low risk of cancer and Type 2 diabetes. They also appear to have healthier brains and better performance on tests of cognition and memory.

For the current study, the research team examined cardiovascular function, damage, and risk factors in GHRD subjects and their relatives. Researchers conducted two phases of measurements in Los Angeles and Ecuador, involving a total of 51 individuals, with 24 diagnosed with GHRD and 27 relatives without GHRD serving as controls.

Key findings from the study included:

• GHRD subjects displayed lower blood sugar, insulin resistance, and blood pressure compared to the control group.
• They also had smaller heart dimensions and similar pulse wave velocity – a measure of stiffness in the arteries – but had lower carotid artery thickness compared to control subjects.
• Despite elevated low-density lipoprotein (LDL), or “bad cholesterol,” levels, GHRD subjects showed a trend for lower carotid artery atherosclerotic plaques compared to controls (7% vs 36%).

"These findings suggest that individuals with GHRD have normal or improved levels of cardiovascular disease risk factors compared to their relatives," said Longo, senior author of the new study. “Although the population tested is small, together with studies in mice and other organisms this human data provide valuable insights into the health effects of growth hormone receptor deficiency and suggest that drugs or dietary interventions that cause similar effects could reduce disease incidence and possibly extend longevity.”

Along with co-corresponding authors Longo and Guevara-Aguirre, the study’s coauthors included Amrendra Mishra and Priya Balasubramanian of USC; Carolina Guevara, Álvaro Villacres, Gabriela Peña, and Daniela Lescano of the Universidad San Francisco de Quito; Alexandra Guevara of the Instituto de Endocrinologia Metabolismo y Reproducción (IEMYR) in Quito; Marco Canepa of the University of Genova, Italy; and John Kopchick of Ohio University. Funding including National Institutes of Health/National Institute on Aging grant P01 AG034906 to Longo.

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JOURNAL

Med

DOI

10.1016/j.medj.2024.03.022 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Normal or improved cardiovascular risk factors in IGF-I deficient adults with growth hormone receptor deficiency

ARTICLE PUBLICATION DATE

26-Apr-2024