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- Muccioli, Giulio G, et al.
(author)
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The endocannabinoid system links gut microbiota to adipogenesis.
- 2010
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In: Molecular systems biology. - : EMBO. - 1744-4292. ; 6:392
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Journal article (peer-reviewed)abstract
- Obesity is characterised by altered gut microbiota, low-grade inflammation and increased endocannabinoid (eCB) system tone; however, a clear connection between gut microbiota and eCB signalling has yet to be confirmed. Here, we report that gut microbiota modulate the intestinal eCB system tone, which in turn regulates gut permeability and plasma lipopolysaccharide (LPS) levels. The impact of the increased plasma LPS levels and eCB system tone found in obesity on adipose tissue metabolism (e.g. differentiation and lipogenesis) remains unknown. By interfering with the eCB system using CB(1) agonist and antagonist in lean and obese mouse models, we found that the eCB system controls gut permeability and adipogenesis. We also show that LPS acts as a master switch to control adipose tissue metabolism both in vivo and ex vivo by blocking cannabinoid-driven adipogenesis. These data indicate that gut microbiota determine adipose tissue physiology through LPS-eCB system regulatory loops and may have critical functions in adipose tissue plasticity during obesity.
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| 2. |
- Reigstad, O, et al.
(author)
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Different patterns of bone fixation with hydroxyapatite and resorbable CaP coatings in the rabbit tibia at 6, 12, and 52 weeks
- 2011
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In: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 99B:1, s. 14-20
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Journal article (peer-reviewed)abstract
- Applying bioactive coatings on orthopedic implants can increase the fixation and long-term implant survival. In our study, we compared a resorbable electrochemically deposited calcium phosphate coating (Bonit®) to a thin (40 μm) plasma-sprayed hydroxyapatite (HA) coating, applied on grit-blasted screw-shaped Ti-6Al-4V implants in the cortical region of rabbit tibia, implanted for 6, 12, and 52 weeks. The removal torque results demonstrated stronger bone-to-implant fixation for the HA than Bonit-coated screws at 6 and 12 weeks. After 52 weeks, the fixation was in favor of the Bonit-coated screws, but the difference was statistically insignificant. Coat flaking and delamination of the HA with multinucleated giant cell activity and bone resorption observed histologically seemed to preclude any significant increase in fixation comparing the HA implants at 6 versus 12 weeks and 12 versus 52 weeks. The Bonit-coated implants exhibited increasing fixation from 6 to 12 weeks and from 12 to 52 weeks, and the coat was resorbed within 6 weeks, with minimal activity of multinucleated giant cells or bone resorption. A different fixation pattern was observed for the two coatings with a sharper but time limited increase in fixation for the HA-coated screws, and a slower but more steadily increasing fixation pattern for the Bonit-coated screws. The side effects were more serious for the HA coating and limiting the expected increase in fixation with time.
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| 3. |
- Reigstad, O., et al.
(author)
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Improved bone ingrowth and fixation with a thin calcium phosphate coating intended for complete resorption
- 2007
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In: Journal of biomedical materials research. Part B, Applied biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 83B:1, s. 9-15
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Journal article (peer-reviewed)abstract
- Bonit is claimed to be a resorbable electrochemically deposited calcium phosphate coating consisting mainly of brushite, which is a hydroxyapatite precursor. This study involved a comparison of Ti6Al4V screw-shaped implants with and without a 15 +/- 5 microm Bonit coating in rabbit tibia and femur, after 6 and 12 weeks of insertion. The biomechanical removal torque test showed significantly increased values for the coated implants after 12 weeks (p < 0.05) but not after 6 weeks of integration. Higher bone-implant contact was found for the coated implants in the tibia after 6 weeks and for both tibial and femoral screws after 12 weeks (p < 0.05). There was no difference in the inflammatory reaction around the implants, and possible grains of the coating could be detected after 6 weeks, but not after 12 weeks of follow-up. This unloaded short-term study has shown promising results for the easily applicable and resorbable coat (Bonit) compared to uncoated titanium-alloy implants.
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| 4. |
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| 5. |
- Vaquer-Sunyer, Raquel, et al.
(author)
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Seasonal patterns in Arctic planktonic metabolism (Fram Strait - Svalbard region)
- 2013
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In: Biogeosciences. - : Copernicus GmbH. - 1726-4189. ; 10:3, s. 1451-1469
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Journal article (peer-reviewed)abstract
- The metabolism of the Arctic Ocean is marked by extremely pronounced seasonality and spatial heterogeneity associated with light conditions, ice cover, water masses and nutrient availability. Here we report the marine planktonic metabolic rates (net community production, gross primary production and community respiration) along three different seasons of the year, for a total of eight cruises along the western sector of the European Arctic (Fram Strait - Svalbard region) in the Arctic Ocean margin: one at the end of 2006 (fall/winter), two in 2007 (early spring and summer), two in 2008 (early spring and summer), one in 2009 (late spring-early summer), one in 2010 (spring) and one in 2011 (spring). The results show that the metabolism of the western sector of the European Arctic varies throughout the year, depending mostly on the stage of bloom and water temperature. Here we report metabolic rates for the different periods, including the spring bloom, summer and the dark period, increasing considerably the empirical basis of metabolic rates in the Arctic Ocean, and especially in the European Arctic corridor. Additionally, a rough annual metabolic estimate for this area of the Arctic Ocean was calculated, resulting in a net community production of 108 g C m(-2) yr(-1).
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| 6. |
- Tremblay, J. E., et al.
(author)
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Global and regional drivers of nutrient supply, primary production and CO2 drawdown in the changing Arctic Ocean
- 2015
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In: Progress in Oceanography. - : Elsevier BV. - 0079-6611. ; 139, s. 171-196
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Journal article (peer-reviewed)abstract
- The main environmental factors driving spatial patterns, variability and change in primary production (PP) in the Arctic Ocean are reviewed. While instantaneous PP rates are predominantly influenced by the local factors affecting light penetration through clouds, sea ice and water, net PP (NPP) at the annual scale is conditioned by a hierarchy of remote and local processes that affect nutrient supply and light availability in general. Nutrient supply sets spatial differences in realized or potential trophic status (i.e. oligotrophic or eutrophic), whereas light availability modulates PP within each regime. Horizontal nutrient supply through Atlantic and Pacific ocean gateways differ markedly, which is explained by their position at opposite ends of the global meridional overturning circulation and imbalanced nitrogen (N) cycling in the Pacific sector. Nutrient supply by rivers is locally important, but does not appear to sustain a major portion of overall pan-Arctic NPP so far. Horizontal nutrient inputs to the surface Arctic Ocean are eventually transferred to the halocline through winter convection and the decomposition of settling organic matter. The subsequent re-injection of these nutrients to the euphotic zone varies by two orders of magnitude across sectors, depending on the strength and persistence of the vertical stratification. Such differences in nutrient delivery are commensurate with those of PP and NPP rates. Widespread N deficiency in surface waters fosters the occurrence and seasonal persistence of subsurface layers of maximum chlorophyll a (SCM) and phytoplankton carbon biomass in several sectors. The contribution of these layers to NPP is possibly higher in the Arctic than in thermally-stratified waters of the subtropical gyres due to a combination of extreme acclimation to low light and a shallow nitracline in the former. The overall impacts of SCM layers on biogeochemical fluxes remain to be quantified directly, both regionally and at the pan-Arctic scale. While CO2 intake by the Arctic Ocean should respond positively to reduced sea-ice extent, which facilitates air-sea exchange, the negative influence of rising temperatures and runoff on CO2 solubility might counteract the positive effect of modest PP increases in seasonally open waters. Overall, this review shows that local changes in light availability resulting from reduced sea-ice is only one factor in the intricate web of local and remote drivers of PP and CO2 drawdown in the Arctic Ocean. Understanding and predicting change requires an integrated biogeochemical approach that connects the small Arctic Ocean to adjacent ones and adequately resolves vertical nutrient supply processes at regional and local scales. (C) 2015 Published by Elsevier Ltd.
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