DenisPBlondin

Nuclear hormone-sensitive lipase regulates adipose tissue mass and adipocyte metabolism In adipocytes, hormone-sensitive lipase (HSL) plays a key role in hydrolyzing triacylglycerols that are stored in lipid droplets. Contrary to the expe…

👀 Nuclear hormone-sensitive lipase regulates adipose tissue mass and adipocyte metabolism

Another outstanding contribution to our understanding of HSL, on adipose biology from the team of @dominiquelangin.bsky.social. Such a fascinating story!

www.sciencedirect.com/science/arti...

Adipose tissue thermogenesis is not proportional to temperature Nature Reviews Endocrinology, Published online: 07 August 2025; doi:10.1038/s41574-025-01163-3Adipose tissue thermogenesis is not proportional to temperature

New content online: Adipose tissue thermogenesis is not proportional to temperature

Shivering, but not adipose tissue thermogenesis, increases as a function of mean skin temperature in cold-exposed men and women Dumont et al. reveal that although heat generated by shivering muscles and by the heart increases based on the degree of cold exposure, heat-producing mechanisms present in adipose tissues like brown and white fat respond in an all-or-nothing fashion. In brown fat, the heat produced likely reflects its thermogenic capacity.

Online now: Shivering, but not adipose tissue thermogenesis, increases as a function of mean skin temperature in cold-exposed men and women

Thank you to:
@NSERC for funding this work
Our incredibly team at @usherbrooke.bsky.social and CRCHUS
The reviewers for their very helpful comments that did improve the manuscript.

and more importantly congratulations 🎉to
@lauralynedumont.bsky.social for leading this challenging study!

📕 One more closing note:

Those who continue to propogate the flawed idea that an 'individulized cooling protocol' is the best way to activate BAT.

Here, we built a skin clamping system to individualize heat loss. Heat produciton was MORE variable than using a fixed temperature for everyone...🙅

📕 In closing:

✔️Cold-stimulated 🔥 is driven by muscle, including shivering and possibly non-shivering mechanisms in the muscle (not measured here).

✔️ Adipose tissue require a minimal cold stress to activate lipolysis, but it is either on or off.

✔️BAT 🔥 is therefore = to its thermogenic capacity.

🙋Is this only limited to BAT though?

6️⃣ WAT lipolysis also did not respond in a graded fashion - it increased in the cold but the magnitude of the lipolytic response was not dependent on skin temperature.

7️⃣ This implies that another 🔥 mechanism, GL/FA cycling also ⬆️, but was not dose-dependent.

🙋What about BAT, what about BAT!

5️⃣Importantly, BAT perfusion and oxidative metabolism increased in the cold, but did not increase as a function of skin temperature.

In other words, with a minimal stress to activate BAT, 🔥 is either on or off - there is not a graded response!

Myocardial perfusion and oxidative metabolism increased, only at the coldest skin temperature, and mainly in women.

🙋Yes, but how does this impact myocardial 💖 metabolism?

4️⃣The perfusion and oxidative metabolism of the myocardium, determined by 11C-acetate PET, only increased at the colder skin temperature and primarily in women.

This represents the first measurement of 💖 metabolism in cold-exposed humans.

Shivering also increased as function of mean skin temperature, in parallel with the increase in heat production. Women shivered to a greater extent than men for both skin temperatures - this is likely a reflection of requiring to recruit a greater proportion of muscle fibers to produce the same amount of heat as the men.

🙋 What about shivering?

3️⃣ Shivering intensity ⬆️ as function of skin cooling, with women shivering to a greater extent than men for the same skin temperature.

Women appeared to recruit a greater #️⃣ of motor units than men, reflected by the ⬆️ in both intensity of continuous and burst shivering.

Heat production increases as function of mean skin temperature, in both men and women. The sex differences in energy expenditure are driven by sex-dependent differences in body mass. The cold-induced increase in energy expenditure did not differ between men and women.

1️⃣ Heat production 🔥 increased as a function of mean skin temperature, in both men and women.

2️⃣ ♂️♀️ differences in 🔥 are driven by differences in body mass. The cold-induced increase in 🔥 did not differ between the sexes.

14 Participants were exposed to a cold stimulus eliciting a mean skin temperature of 30 or 26°C. They underwent PET imaging with [11C]-acetate and FDG to examine organ-specific metabolism in response to the cold.

We were then interested in understanding how different organs respond to different cold stimulations, particularly adipose tissue (brown and white adipose tissue).

So we took advantage of our closed-loop temp control system to clamp the mean skin temp of our participants to either 30°C or 26°C.

Thermogenic responses to different clamped skin temperatures in cold-exposed men and women - PubMed Despite many decades of research examining thermoregulatory responses under varying cold stresses in humans, very little is known about the variability in metabolic heat production and shivering activ...

This was a follow-up on a paper we published recently (pubmed.ncbi.nlm.nih.gov/35411809/) which investigated the variability in shivering response when clamping mean skin temp to 31°C, 29°C or 27°C.

As expected:
✔️ Heat production ⬆️ as function of skin temp
✔️ Shivering paralleled this increase in 🔥

🧪📣Have you ever wondered how shivering and brown adipose tissue interact and respond to different degrees of cold stress in humans?❄️

Conclusion: Shivering, but not adipose tissue thermogenesis, increases as a function of mean skin temp in cold-exposed humans.

authors.elsevier.com/a/1lRgJ5WXUl...

🧪 Very pleased to have contributed to this important and very comprehensive review on a topic I have thought about for many years - it lays an important foundation to some original human data we hope to put out soon!

A dark haired woman wearing a gray one piece swimsuite lies in a tub of water.

#FridayPhysiologyFact: APS member @denispblondin.bsky.social‬ shares his thoughts with ‪@gretchenxreynolds.bsky.social‬ @washingtonpost.com about whether or not cold plunges are good for us: ow.ly/GEeN50W4oFC #ISpyPhysiology 🧪

🔊PSA:

If you are studying BAT in humans...👏Infrared👏Thermography👏of👏supraclavicular👏fossa👏is👏not👏BAT👏THERMOGENESIS!!!!!!!
🧪

Stop saying it is, it's not, and you are actively misleading the field!

Hi Monica, I would love to be added to this feed. I study thermal physiology and energy metabolism mainly in humans.

My Google Scholar profile is: scholar.google.ca/citations?us...

Thank you!

⏳Many years in the making, including collaborating with engineers to develop a new temperature control system.

This study provides the first ever dose-response of BAT, WAT and myocardial thermogenesis in cold-exposed humans ❄️.

We hope to receive some insightful feedback on our findings!

After several decades, in a comorbidity-free U.S.-based population with #T2D the use of GLP-1 RAs did not increase their risk of pancreatitis. Their use was associated with a lower lifetime risk of #pancreatitis www.mdpi.com/2077-0383/14...

Anyone interested in BAT research is encouraged to read through this insightful perspective from some of the top BAT researchers in the world for valuable insight on some of the matters of debate and the experiments required to address them.

The latter has been the most problematic method used in human BAT research because:

1️⃣ It's not reproducible.

2️⃣ Self-perceived shivering is not 🟰 to actual shivering.

3️⃣ It fabricates variability

4️⃣ Creates false dichotomy of BAT+ vs BAT-, which really means adequately cooled vs. not cold.

1️⃣ Fixed temperature vs. Personalized cooling - your research question will determine which is most appropriate.

2️⃣ If personalizing the cold, personalize using a reproducible metric: either heat loss or heat production.

3️⃣ DO NOT base stimulus on cold perception or visual detection of shivering.

Emerging debates and resolutions in brown adipose tissue research The explosive growth in the study of human BAT has led over time to lively debates over central physiological concepts. This perspective discusses six areas of current disagreement and proposes experiments to achieve resolutions and move the field forward.

Since 2007, there's been a surge in studies investigating the function of BAT. Along the way, there's been much debate on various topics.

In this perspective, we highlight the importance of carefully considering your cooling protocol when studying BAT🔥in humans.❄️

www.cell.com/cell-metabol...

Human adipose depots’ diverse functions and dysregulations during cardiometabolic disease - npj Metabolic Health and Disease npj Metabolic Health and Disease - Human adipose depots’ diverse functions and dysregulations during cardiometabolic disease

Our latest review in NJP Metabolic Health and Disease: eur02.safelinks.protection.outlook.com?url=https%3A...

Tirzepatide for Obesity Treatment and Diabetes Prevention | NEJM Obesity is chronic disease and causal precursor to myriad other conditions, including type 2 diabetes. In an earlier analysis of the SURMOUNT-1 trial, tirzepatide was shown to provide substantial a...

#Tirzepatide for Obesity Treatment & Diabetes Prevention
SURMOUNT-1 Trial

✅ Reduced progression to T2DM by 93%
#CardioSky #EndoSky #MedSky #NEJM
www.nejm.org/doi/full/10....

Created a NeuroMetabolism starter pack. It’s just beginning…who to add?? #neurometabolism #metabolism #brain #peripheralnerve go.bsky.app/4nbSbNR

In our recent paper in @Cell_Metabolism @jananerahbani and no-twitter Jakub Bunk demonstrate that thermogenic adipocytes utilize non-paralogous protein redundancy—through UCP1 and CKB—to promote cold-induced energy dissipation. www.cell.com/cell-metabol...

✅Love cold exposure❄️, heat exposure🔥, or exercise physiology🚴?
✅Looking to do an MSc/PhD/Postdoc🔬?
✅Interested in learning how to perform PET imaging, high-resolution respirometry, stable isotope methods or indirect calorimetry?

Come join us in Sherbrooke, Canada 🇨🇦!