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Diabète de type 1 : des cellules productrices d’insuline créées en laboratoire

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Ce diabète se caractérise par l’absence totale de production d’insuline. Les 300 000 Canadiens atteints dépendent d’injections quotidiennes d’insuline ou d’une pompe à insuline pour survivre.

Le diabète de type 1

  • Il s’agit d’une maladie auto-immune qui détruit les cellules bêta productrices d’insuline du pancréas.
  • L’incapacité de l’insuline à réguler le taux de glucose dans le sang mène à des pics de glycémie qui peuvent causer de graves dommages aux organes (insuffisance rénale, maladie cardiaque et accident vasculaire cérébral) et même la mort.
  • Son origine reste inconnue.

À l’heure actuelle, on pense que le diabète de type 1 se manifeste quand le système immunitaire détruit les cellules qui produisent l’insuline.

Une avancée significative

La possibilité de remplacer ces cellules disparues représente donc l’un des espoirs de traitement de la maladie.

Jusqu’à aujourd’hui toutefois, les scientifiques n’avaient pas été en mesure de produire des cellules en laboratoire qui fonctionnent comme celles des adultes en bonne santé.

Les médecins américains Gopika Nair et Matthias Hebrok de l’Université de la Californie à San Francisco affirment qu’ils ont réussi cet exploit.

Nous pouvons maintenant créer des cellules productrices d’insuline qui ressemblent beaucoup aux cellules bêta du pancréas que vous et moi avons dans notre corps.

Matthias Hebrok

« Il s’agit d’une étape cruciale dans l’atteinte de notre objectif de créer des cellules qui pourraient être transplantées chez les personnes atteintes de diabète », poursuit le Pr Hebrok.

Les personnes dont la vie est en danger en raison de complications potentiellement mortelles peuvent être admissibles à une greffe du pancréas d’un donneur décédé, mais la liste d’attente est longue.

Par exemple, aux États-Unis, 1,5 million de personnes vivent avec le diabète de type 1, mais seulement 1000 d’entre elles reçoivent une greffe de pancréas chaque année.

Et cette chirurgie n’est pas sans risque. Les receveurs doivent prendre des médicaments immunosuppresseurs à vie et beaucoup de greffes finissent par échouer pour une raison ou une autre.

Les greffes d’îlots pancréatiques (des groupes de cellules contenant des cellules bêta saines) font actuellement l’objet d’essais cliniques, mais dépendent toujours des pancréas de donneurs décédés.

Des grappes de cellules bêta pancréatiques dérivées de cellules souches pluripotentes humaines.Agrandir l’imageDes grappes de cellules bêta pancréatiques dérivées de cellules souches pluripotentes humaines. Les cellules productrices d’insuline apparaissent en vert. Le rouge indique la présence d’une protéine clé impliquée dans la production d’insuline. Photo : UCS

Pour toutes ces raisons, le recours aux cellules souches permettant de cultiver en laboratoire des cellules bêta saines pouvant être transplantées chez des patients représente une avenue de recherche intéressante.

Mais les scientifiques devaient trouver un moyen de reprogrammer des cellules souches pour en faire des cellules bêta matures.

Les cellules que nous et d’autres équipes produisions étaient bloquées à un stade immature où elles n’étaient pas capables de répondre adéquatement à la glycémie et de sécréter correctement l’insuline.

Matthias Hebrok

Or, l’équipe de Matthias Hebrok a découvert que la clé de la maturation complète des cellules bêta cultivées en laboratoire réside dans un aspect négligé à ce jour du développement des cellules bêta, c’est-à-dire le processus physique par lequel les cellules se séparent du reste du pancréas et forment les îlots dits de Langerhans.

Ces îlots sont formés de cellules endocrines capables de synthétiser des hormones comme l’insuline. Ils ne constituent que 1 % à 2 % de la masse totale du pancréas.

L’un des principes clés en biologie est que la forme suit la fonction, c’est pourquoi nous avons pensé que la formation d’îlots de Langerhans pourrait être un processus important pour permettre aux cellules bêta de mûrir correctement.

Matthias Hebrok

Les scientifiques ont ainsi reproduit ce processus en laboratoire en séparant artificiellement des cellules souches pancréatiques partiellement différenciées et en les transformant en amas semblables à des îlots. Ils ont alors constaté que le développement des cellules s’est accéléré.

Illustration de cellules pancréatiques.Agrandir l’imageLorsque des cellules d’îlots de Langerhans produites à partir de cellules souches humaines en laboratoire sont transplantées chez la souris, elles forment des grappes et commencent à produire les trois principales hormones régulatrices de la glycémie produites par les îlots pancréatiques sains. Photo : UCSF

Mieux : non seulement les cellules bêta ont commencé à réagir à la glycémie comme des cellules matures productrices d’insuline, mais tout l’entourage de l’îlot semblait aussi se développer d’une façon jamais observée en laboratoire.

Ils ont ensuite testé leur découverte sur des souris en leur transplantant des îlots cultivés en laboratoire. Le résultat est sans appel : ces cellules furent fonctionnelles en seulement quelques jours en produisant de l’insuline en réponse à la glycémie.

Le saviez-vous?

Environ 8,5 % de la population adulte était diabétique à l’échelle planétaire. En 2015, le diabète a été la cause directe de 1,6 million de décès. (source : Organisation mondiale de la Santé)

Vers un traitement

L’équipe d’Hebrok travaille maintenant, en collaboration avec des généticiens, des bio-ingénieurs et autres chercheurs, à faire passer sa thérapie dégénérative « du rêve à la réalité ».

Les traitements actuels, comme les injections d’insuline, ne traitent que les symptômes de la maladie. Notre travail nous indique plusieurs avenues passionnantes pour enfin trouver un remède.

Gopika Nair

« Nous sommes enfin en mesure d’aller de l’avant sur un certain nombre de fronts différents qui nous étaient auparavant fermés. Les possibilités actuelles semblent infinies », conclut Matthias Hebrok.

Le détail de ces travaux est publié dans la revue Nature cell biology (Nouvelle fenêtre) (en anglais)

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Trudeau Government Should Turn to Sustainable Floor Heating In Its New Deal

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A consortium has been chosen by Public Services and Procurement Canada (PSPC) to manage the $1.1-billion overhaul of five heating and cooling plants in the National Capital Region. However, this decision has been met with a lot of disapproval by the country’s largest federal public service union.

Early June, the department announced that Innovate Energy has been awarded the 30-year contract “to design, retrofit, maintain and operate the plants,”winning the bid over a rival group that included SNC-Lavalin.

Minister of Environment, Catherine McKenna, said the federal government was “leading by example” in its bid to drastically reduce the amount of greenhouse gas emissions across the country. McKenna noted that by supporting this project, they’re utilizing heating and cooling infrastructure to promote a more environmentally friendly option.

“We’re very proud that our government is working with partners like Innovate Energy to modernize this critical infrastructure,” she said during the announcement at one of the facilities that will be upgraded, the Cliff Heating and Cooling Plant in downtown Ottawa.

The plants would be known as the district energy system and would heat 80 buildings in the area with steam. It is also expected to cool 67 of these buildings with chilled water through more than 14 kilometres of underground pipes.

Under the Energy Services Acquisition Program, PSPC will be tasked with modernizing the outdated technology in the plants to lower emissions and supportgrowth in the eco-friendly technology sector.

During the first stage of the overhaul, the system would be converted from steam to low temperature hot water and then switched from steam to electric chillers—with the estimated completion date being 2025. PSPC notes that the project will reduce current emissions by 63 per cent, the equivalent of removing 14,000 non-eco-friendly cars off the road.

Afterwards, the natural gas powering the plant will then be replaced by carbon-neutral fuel sources, which according to estimated will reduce emissions by a further 28 per cent. The renovation project is bound to save the government an estimated fee of more than $750 million in heating and cooling costs in the next 40 years.

Furthermore, the implementation of radiant floor heating in Ottawa by the federal government would be an additional step in driving its agenda for a more eco-friendly state.

According to the U.S. Department of Energy’s Energy Savers website, radiant floor heating has a lot of benefits and advantages over alternate heat systems and can cut heating costs by 25 to 50 per cent.

“It is more efficient than baseboard heating and usually more efficient than forced-air heating because no energy is lost through ducts,” the website states.

Radiant floor heating provides an equal amount of heat throughout a building, including areas that are difficult to heat, such as rooms with vaulted ceilings, garages or bathrooms. Consideringit warms people and objects directly—controlling the direct heat loss of the occupant—radiant floor heating provides comfort at lower thermostat settings.

“Radiators and other forms of ‘point’ heating circulate heat inefficiently and hence need to run for longer periods to obtain comfort levels,” reports the Residential Energy Services Network (RESNet).

Radiant heating is a clean and healthy option—a perfect choice for those with severe allergies—as it doesn’t rely on circulating air, meaning there are no potentially irritating particles blowing around the room. Additionally, it is more energy efficient, aesthetically pleasing with wall radiators or floor registers and virtually noiseless when in operation.

“They draw cold air across the floor and send warm air up to the ceiling, where it then falls, heating the room from the top down, creating drafts and circulating dust and allergens.”

It is important for the leadership in Ottawa to equally drive the adoption of radiant floor heating as doing this would lead to increased usage in residential buildings—and even government-owned buildings.

However, in October, the Public Service Alliance of Canada (PSAC), a representative body of employees of the plants,began a campaign target at the government against their decision to use a public-private partnership (P3) for the retrofitting project, citing concerns about costs and safety.

According to the union, outside employees won’t be bound to the same health and safety standards of government workers and that typically P3 projects cost a lot more than traditional public financing deals.

The union demands that the government scraps the proposed project and meet PSAC members and experts to brainstorm on a new way forward that would ensure federal employees continue to operate and maintain the plants.

However, parliamentary secretary to public services and procurement minister, Steve MacKinnon said that the union officials have consulted him but that after conducting an analysis, the P3 option was still the best for the job.

“We didn’t have (to) sacrifice on safety or health — we didn’t have to sacrifice on job security,” he said.

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Steps to becoming a Data Scientist

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Data science has become one of the most in-demand career paths in this century, according to Business Insider. With the amount of information being circulated online, it has created a huge demand for storing, interpreting and implementing big data for different purposes—hence the need for a data scientist.

Today, there too much information flying around for regular people to process efficiently and use. Therefore, it has become the responsibility of data scientists to collect, organize and analyze this data. Doing this helps various people, organizations, enterprise businesses and governments to manage, store and interpret this data for different purposes.

Though data scientists come from different educational backgrounds, a majority of them need to have a technical educational background. To pursue a career in data science, computer-related majors, graduations and post graduations in maths and statistics are quite useful.

Therefore, the steps to becoming a data scientist are quite straightforward.  After obtaining a bachelor’s degree in an IT related field—such as computer science, maths or physics—you can also further your education by obtaining a master’s degree in a data science or any other related field of study. With the necessary educational background, you can now search for a job and obtain the required experience in whichever filed you choose to invest your acquired skills.

Here are the necessary steps to be taken to become a data scientist.

Step 1: Obtain the necessary educational requirements

As earlier noted, different educational paths can still lead to a career in data science. However, it is impossible to begin a career in data science without obtaining a collegiate degree—as a four-year bachelor’s degree is really important. However, according to a report by Business Insider, over 73% of data scientist in existence today have a graduate degree and about 38% of them hold a Ph.D. Therefore, to rise above the crowd and get a high-end position in the field of data science, it is important to have a Master’s degree or a Ph.D.—and with various online data science masters program, obtaining one is quite easy.

Some institutions provide data science programs with courses that will equip students to analyze complex sets of data. These courses also involve a host of technical information about computers, statistics, data analysis techniques and many more. Completing these programs equips you with the necessary skills to function adequately as a data scientist.

Additionally, there are some technical—and computer-based degrees—that can aid you begin a career in data science. Some of them include studies in, Computer Science, Statistics, Social Science, Physics, Economics, Mathematics and Applied Math. These degrees will imbibe some important skills related to data science in you—namely, coding, experimenting, managing large amounts of data, solving quantitative problems and many others.

Step 2: Choose an area of specialization

There rarely exists an organization, agency or business today that doesn’t require the expertise of a data scientist. Hence, it is important that after acquiring the necessary education to start a career as a data scientist, you need to choose an area of specialization in the field you wish to work in.

Some of the specializations that exist in data science today include automotive, marketing, business, defence, sales, negotiation, insurance and many others.

Step 3: Kick start your career as a data scientist

After acquiring the necessary skills to become a data scientist, it is important to get a job in the filed and company of your choice where you can acquire some experience.

Many organizations offer valuable training to their data scientists and these pieces of training are typically centred around the specific internal systems and programs of an organization. Partaking in this training allows you learn some high-level analytical skills that were not taught during your various school programs—especially since data science is a constantly evolving field.

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Artificial intelligence pioneers win tech’s ‘Nobel Prize’

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Computers have become so smart during the past 20 years that people don’t think twice about chatting with digital assistants like Alexa and Siri or seeing their friends automatically tagged in Facebook pictures.

But making those quantum leaps from science fiction to reality required hard work from computer scientists like Yoshua Bengio, Geoffrey Hinton and Yann LeCun. The trio tapped into their own brainpower to make it possible for machines to learn like humans, a breakthrough now commonly known as “artificial intelligence,” or AI.

Their insights and persistence were rewarded Wednesday with the Turing Award, an honor that has become known as technology industry’s version of the Nobel Prize. It comes with a $1 million prize funded by Google, a company where AI has become part of its DNA.

The award marks the latest recognition of the instrumental role that artificial intelligence will likely play in redefining the relationship between humanity and technology in the decades ahead.

Artificial intelligence is now one of the fastest-growing areas in all of science and one of the most talked-about topics in society,” said Cherri Pancake, president of the Association for Computing Machinery, the group behind the Turing Award.

Although they have known each other for than 30 years, Bengio, Hinton and LeCun have mostly worked separately on technology known as neural networks. These are the electronic engines that power tasks such as facial and speech recognition, areas where computers have made enormous strides over the past decade. Such neural networks also are a critical component of robotic systems that are automating a wide range of other human activity, including driving.

Their belief in the power of neural networks was once mocked by their peers, Hinton said. No more. He now works at Google as a vice president and senior fellow while LeCun is chief AI scientist at Facebook. Bengio remains immersed in academia as a University of Montreal professor in addition to serving as scientific director at the Artificial Intelligence Institute in Quebec.

“For a long time, people thought what the three of us were doing was nonsense,” Hinton said in an interview with The Associated Press. “They thought we were very misguided and what we were doing was a very surprising thing for apparently intelligent people to waste their time on. My message to young researchers is, don’t be put off if everyone tells you what are doing is silly.” Now, some people are worried that the results of the researchers’ efforts might spiral out of control.

While the AI revolution is raising hopes that computers will make most people’s lives more convenient and enjoyable, it’s also stoking fears that humanity eventually will be living at the mercy of machines.

Bengio, Hinton and LeCun share some of those concerns especially the doomsday scenarios that envision AI technology developed into weapons systems that wipe out humanity.

But they are far more optimistic about the other prospects of AI empowering computers to deliver more accurate warnings about floods and earthquakes, for instance, or detecting health risks, such as cancer and heart attacks, far earlier than human doctors.

“One thing is very clear, the techniques that we developed can be used for an enormous amount of good affecting hundreds of millions of people,” Hinton said.

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