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Researchers find neurons are capable of cooling down inflammation in fat tissue

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SF1 neurons in the ventromedial hypothalamus were found to suppress inflammation in inguinal WAT in diet-induced obese mice through sympathetic nerves innervating the tissue, while they had no effect on epididymal WAT. The SF1 neurons also increased thermogenic function in interscapular BAT in diet-induced obese mice. Thus, the suppressive role of SF1 neurons in inflammatory response in subcutaneous (inguinal) WAT may explain why subcutaneous obesity has lower incidence of metabolic diseases than abdominal obesity. Credit: National Institute for Physiological Sciences

Just as there are different types of fat in food, there are different types of fat tissue found within the body. White adipose tissue (WAT) is the most abundant form of fat, while brown adipose tissue (BAT) plays an important role in thermogenesis, the process in which heat is produced by burning calories.

Recent studies indicate that differences in the association of WAT depot mass with may arise from different properties of subcutaneous versus abdominal WAT. Subcutaneous WAT manifests a lower extent of inflammation than that in abdominal WAT. Inflammation in those areas containing WAT can influence how obesity affects overall metabolic and cardiovascular health. However, it is unclear whether the nervous system controls inflammation differently in different regions of fat. Researchers in Japan have shed new light on a type of neuron in the brain that plays an important role in inflammation within these types of fat.

In a new study published in Cell Reports, researchers led by the National Institute for Physiological Sciences (NIPS) employed a high fat diet–fed mouse model to demonstrate how neurons that express a protein called steroidogenic factor 1 (SF1) influence inflammation in different regions or “depots” of fat.

It has been previously shown that SF1-expressing neurons reside in the hypothalamus, a region of the brain that controls hunger and peripheral metabolism. The NIPS-led research team set out to investigate the influence of SF1 neurons on different fat depots, including WAT found in the inguinal (subcutaneous) and epididymal (abdominal) regions, in who are fed a high-fat diet.

“We first investigated the effects of deactivating SF1-expressing neurons in the hypothalamus,” says senior author of the study Yasuhiko Minokoshi. “We found that mice without the SF1-expressing neuron gained substantially more weight on both normal and high-fat diets. Inguinal WAT weight increased in these mice, but interestingly, epididymal WAT weight actually decreased, while BAT showed no significant change. This indicated that SF1 neurons appear to regulate fat metabolism differently in different regions of the mouse body.”

The researchers found that expression of inflammatory and immune-cell markers and infiltration of the immune cells were elevated in the inguinal WAT of mice lacking SF1-expressing neurons and who were fed a high-fat diet, while in epididymal WAT, those markers exhibited high values in both mice lacking and not lacking SF1-expressing neurons. In BAT, markers of thermogenesis were significantly decreased in mice lacking SF1-expressing neurons. Conversely, activation of SF1 neurons in mice fed the high-fat diet led to decreased levels of inflammatory gene expression in inguinal WAT, but not in epididymal WAT, and increased thermogenic function in BAT.

“Our findings indicate that SF1 neurons in the hypothalamus help suppress induced by a in the inguinal WAT,” says one of the double corresponding authors, Kunio Kondoh.

“These neurons also activate thermogenic activity in BAT, but do not appear to affect inflammatory response or thermogenesis in epididymal WAT,” says lead author Misbah Rashid.

The researchers further found that SF1 neurons exert their effect through sympathetic nerves that connect to inguinal WAT. Some specific SF1 neurons appear to regulate inflammatory response and thermogenesis differently in individual depots of fat through sympathetic nerves innervating the tissues. The team’s research improves our understanding of SF1 neurons and how they control inflammation, one of the driving factors of diseases related to obesity.

More information:
Misbah Rashid et al, Inhibition of high-fat diet-induced inflammatory responses in adipose tissue by SF1-expressing neurons of the ventromedial hypothalamus, Cell Reports (2023). DOI: 10.1016/j.celrep.2023.112627

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National Institute for Physiological Sciences

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Canada to donate up to 200,000 vaccine doses to combat mpox outbreaks in Africa

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The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.

It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.

Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”

Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.

Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.

A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.

On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.

Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”

But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”

“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.

Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.

Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.

Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.

“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.

“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”

This report by The Canadian Press was first published Sept. 13, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

The Canadian Press. All rights reserved.

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How many Nova Scotians are on the doctor wait-list? Number hit 160,000 in June

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HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.

The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.

Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.

“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”

The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.

A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.

Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.

“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.

Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.

The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.

“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.

This report by The Canadian Press was first published Sept. 11, 2024.

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Newfoundland and Labrador monitoring rise in whooping cough cases: medical officer

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ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.

Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.

Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.

Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.

The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.

“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.

Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.

Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.

Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.

A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.

This report by The Canadian Press was first published Sept. 10, 2024.

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