| 1. |
- Grahnemo, Louise, et al.
(författare)
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Increased bone mass in a mouse model with low fat mass.
- 2018
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 315:6
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Tidskriftsartikel (refereegranskat)abstract
- Mice with impaired acute inflammatory responses within adipose tissue display reduced diet-induced fat mass gain associated with glucose intolerance and systemic inflammation. Therefore, acute adipose tissue inflammation is needed for a healthy expansion of adipose tissue. Because inflammatory disorders are associated with bone loss, we hypothesized that impaired acute adipose tissue inflammation leading to increased systemic inflammation results in a lower bone mass. To test this hypothesis, we used mice overexpressing an adenoviral protein complex - the receptor internalization and degradation (RID) complex that inhibits pro-inflammatory signaling - under the control of the aP2-promotor (RID tg mice), resulting in suppressed inflammatory signaling in adipocytes. As expected, RID tg mice had a lower high-fat diet-induced weight and fat mass gain and higher systemic inflammation than their littermate wild type controls. Contrary to our hypothesis, the RID tg mice had increased bone mass in long bones and vertebrae, affecting trabecular and cortical parameters, as well as improved humeral biomechanical properties. We did not find any differences in bone formation or resorption parameters as determined by histology or enzyme immunoassay. However, bone marrow adiposity, often negatively associated with bone mass, was decreased in male RID tg mice as determined by histological analysis of tibia. In conclusion, mice with reduced fat mass, due to impaired adipose tissue inflammation, have increased bone mass.
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| 2. |
- Lagerquist, Marie K, et al.
(författare)
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Acute fat loss does not affect bone mass
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Obesity has previously been thought to protect bone since high body weight and body mass index are associated with high bone mass. However, some more recent studies suggest that increased adiposity negatively impacts bone mass. Here, we aimed to test whether acute loss of adipose tissue, via adipocyte apoptosis, alters bone mass in age-related obese mice. Adipocyte apoptosis was induced in obese male FAT-ATTAC mice through AP20187 dimerizer-mediated activation of caspase 8 selectively in adipocytes. In a short-term experiment, dimerizer was administered to 5.5 month-old mice that were terminated 2 weeks later. At termination, the total fat mass weighed 58% less in dimerizer-treated mice compared with vehicle-treated controls, but bone mass did not differ. To allow for the detection of long-term effects, we used 9-month-old mice that were terminated six weeks after dimerizer administration. In this experiment, the total fat mass weighed less (- 68%) in the dimerizer-treated mice than in the controls, yet neither bone mass nor biomechanical properties differed between groups. Our findings show that adipose tissue loss, despite the reduced mechanical loading, does not affect bone in age-related obese mice. Future studies are needed to test whether adipose tissue loss is beneficial during more severe obesity.
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