scholarly journals Acylated and unacylated ghrelin directly regulate ß-3 stimulated lipid turnover in rodent subcutaneous and visceral adipose tissue ex vivo but not in vivo

Adipocyte ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Daniel T. Cervone ◽  
Justin Sheremeta ◽  
Emily N. Kraft ◽  
David J. Dyck
Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Satoshi Nishimura ◽  
Mika Nagasaki ◽  
Ichiro Manabe ◽  
Kinya Seo ◽  
Takashi Kadowaki ◽  
...  

Metabolic syndrome is a major risk factor of cardiovascular events, and obese visceral adipose tissue remodeling and malfunctioning based on chronic inflammation plays a central role. To assess dynamic multi-cellular interplay, a novel ex vivo (a–c) and in vivo (d–f) adipose tissue imaging method was developed. We found close spatial and temporal interrelationships between angiogenesis and adipogenesis, and both were augmented in obese adipose (c,arrow). In addition, we found increased leukocyte-platelet-endothelial cell interactions in the micro-circulation of obese visceral adipose that were indicative of activation of the leukocyte adhesion cascade, a hallmark of inflammation (e,f). Both macrophages and endothelial cells showed increased adhesion molecules including ICAM-1 and Selectin families, and P-selectin positive platelets were increased locally in obese adipose. Up-regulated expression of adhesion molecules on multiple cell types suggests their increased interactions contribute to local activation of inflammatory processes within visceral obese adipose tissue. Interestingly, the heightened leukocyte-platelet-endothelial interactions were not observed in obese subcutaneous fat pads. Our results demonstrated the power of our imaging technique to analyze complex inflammatory cellular interplays in vivo and to evaluate new therapeutic interventions against them. Results also indicate that visceral adipose tissue obesity is an inflammatory disease.


2020 ◽  
Author(s):  
Ada Admin ◽  
Julia Braune ◽  
Andreas Lindhorst ◽  
Janine Fröba ◽  
Constance Hobusch ◽  
...  

Obesity is associated with a chronic low-grade inflammation in visceral adipose tissue (AT) characterized by an increasing number of adipose tissue macrophages (ATMs) and linked to type 2 diabetes. AT inflammation is histologically indicated by the formation of so-called crown-like structures (CLS), as accumulation of ATMs around dying adipocytes, and the occurrence of multi-nucleated giant cells (MGCs). However to date, the function of MGCs in obesity is unknown. Hence, the aim of this study was to characterize MGCs in AT and unravel the function of these cells. <p>We demonstrate that MGCs occur in obese patients and after 24 weeks of high fat diet (HFD) in mice, accompanying signs of AT inflammation and then represent ~3% of ATMs in mice. Mechanistically, we found evidence that adipocyte death triggers MGC formation. Most importantly, MGCs in obese AT have a higher capacity to phagocytose oversized particles, such as adipocytes, as shown by live-imaging of AT, 45 µm bead uptake <i>ex vivo</i> and a higher lipid content <i>in vivo</i>. Finally, we show that IL-4 treatment is sufficient to increase the number of MGCs in AT, whereas other factors maybe more important for endogenous MGC formation <i>in vivo</i>.</p>


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Elena Topchiy ◽  
Yingjin Wang ◽  
John Boyd ◽  
Keith R Walley

Background: To prevent severe inflammation during infection, the patient must quickly clear bacterial endotoxins from the circulation before they accumulate and are able to interact with immune cells and vascular endothelium, and induce inflammatory organ failure. Bacterial endotoxins are carried within lipoprotein particles. Thus, one mechanism of action for sepsis treatments could be acceleration of lipoprotein clearance by adipocytes and hepatocytes. Proprotein convertase subtilisin/kexin type 9 (PCSK9) decreases the rate of lipoprotein clearance. We have recently reported that reduced function of PCSK9 improves outcome and prevents cardiovascular complications associated with sepsis. Hypothesis: PCSK9 inhibits LDL associated LPS clearance through hepatic LDLR and VLDL associated LPS clearance through adipose VLDLR. Methods and Results: Using siRNA against the LDLR in HepG2 hepatocytes decreased uptake of fluorescently labeled LPS (fLPS) after 48 hours by 1.50±0.10 fold (n=3, p<0.05). Addition of recombinant PCSK9 in the absence of LDLR did not alter uptake of LPS. We confirmed that hepatic uptake of LPS is exclusively via the LDLR by fluorescent microscopy of ex vivo LPS treated primary hepatocytes isolated from LDLR -/- mice. To address the importance of the LDLR upon clearance of LPS from plasma, we injected fLPS into the portal vein of LDLR-/-, PCSK9-/- and wild type mice (WT). Compared to WT, LDLR-/- mice had 36±13% (n=9, p<0.001) increase in plasma LPS after 1 hour, whereas PCSK9-/- show a significant decrease (28±4%, n=9, p<0.001) in plasma LPS. LDLR-/-, but not PCSK9-/- mice showed 46±7% decrease (n=10, p<0.05) in hepatic uptake. On the other hand, compared to the WT PCSK9-/- mice had 200±35% (n=8, p<0.001) increase in LPS uptake by visceral adipose tissue whereas LDLR-/- had no effect compared to WT mice. To further investigate LPS uptake by adipose tissue we injected flLPS into the tail vein of VLDLR-/- and WT mice. VLDLR-/- mice had 33±6% (n=10, p<0.001) decrease in visceral adipose tissue uptake, with no significant change in hepatic uptake. Conclusions: Expression of hepatic LDLR and adipose VLDLR is mainly regulated by PCSK9 and both play important role in clearing LPS from circulation.


2019 ◽  
Vol 2 (6) ◽  
pp. e201900561 ◽  
Author(s):  
Dong Seong Cho ◽  
Bolim Lee ◽  
Jason D Doles

Obesity is a serious health concern and is associated with a reduced quality of life and a number of chronic diseases, including diabetes, heart disease, stroke, and cancer. With obesity rates on the rise worldwide, adipose tissue biology has become a top biomedical research priority. Despite steady growth in obesity-related research, more investigation into the basic biology of adipose tissue is needed to drive innovative solutions aiming to curtail the obesity epidemic. Adipose progenitor cells (APCs) play a central role in adipose tissue homeostasis and coordinate adipose tissue expansion and remodeling. Although APCs are well studied, defining and characterizing APC subsets remains ambiguous because of ill-defined cellular heterogeneity within this cellular compartment. In this study, we used single-cell RNA sequencing to create a cellular atlas of APC heterogeneity in mouse visceral adipose tissue. Our analysis identified two distinct populations of adipose tissue–derived stem cells (ASCs) and three distinct populations of preadipocytes (PAs). We identified novel cell surface markers that, when used in combination with traditional ASC and preadipocyte markers, could discriminate between these APC subpopulations by flow cytometry. Prospective isolation and molecular characterization of these APC subpopulations confirmed single-cell RNA sequencing gene expression signatures, and ex vivo culture revealed differential expansion/differentiation capabilities. Obese visceral adipose tissue featured relative expansion of less mature ASC and PA subpopulations, and expression analyses revealed major obesity-associated signaling alterations within each APC subpopulation. Taken together, our study highlights cellular and transcriptional heterogeneity within the APC pool, provides new tools to prospectively isolate and study these novel subpopulations, and underscores the importance of considering APC diversity when studying the etiology of obesity.


2011 ◽  
Vol 204 (1) ◽  
pp. S319
Author(s):  
Kathleen Vincent ◽  
Fernanda Vergara ◽  
Egle Bytautiene ◽  
Jingna Wei ◽  
Igor Patrikeev ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sai Sahana Sundararaman ◽  
Linsey J. F. Peters ◽  
Yvonne Jansen ◽  
Selin Gencer ◽  
Yi Yan ◽  
...  

AbstractThe calcium sensing receptor (CaSR) is a G-protein coupled receptor that especially plays an important role in the sensing of extracellular calcium to maintain its homeostasis. Several in-vitro studies demonstrated that CaSR plays a role in adipose tissue metabolism and inflammation, resulting in systemic inflammation and contributing to atherosclerosis development. The aim of this study was to investigate whether adipocyte CaSR plays a role in adipose tissue inflammation in-vivo and atherosclerosis development. By using a newly established conditional mature adipocyte specific CaSR deficient mouse on a hyperlipidemic and atherosclerosis prone Apoe−/− background it could be shown that CaSR deficiency in adipocytes does neither contribute to initiation nor to progression of atherosclerotic plaques as judged by the unchanged lesion size or composition. Additionally, CaSR deficiency did not influence gonadal visceral adipose tissue (vAT) inflammation in-vivo, although a small decrease in gonadal visceral adipose cholesterol content could be observed. In conclusion, adipocyte CaSR seems not to be involved in vAT inflammation in-vivo and does not influence atherosclerosis development in hyperlipidemic Apoe−/− mice.


Author(s):  
Alessandro De Stefano ◽  
Manfredi Tesauro ◽  
Nicola Di Daniele ◽  
Giuseppina Vizioli ◽  
Francesca Schinzari ◽  
...  

As novel drug treatments for diabetes have shown favorable cardiovascular effects, interest has mounted with regard to their possible vascular actions, particularly in relation to visceral adipose tissue perfusion and remodeling in obesity. The present study tested the vasorelaxing effect of the SGLT2 (sodium-glucose transporter type 2) inhibitor canagliflozin in arteries from visceral adipose tissue of either nonobese or obese humans and investigated the underlying mechanisms. Also, the vasorelaxing effect of canagliflozin and the GLP-1 (glucagon-like peptide 1) agonist liraglutide were compared in arteries from obese patients. To these purposes, small arteries (116–734 μm) isolated from visceral adipose tissue were studied ex vivo in a wire myograph. Canagliflozin elicited a higher concentration-dependent vasorelaxation in arterioles from obese than nonobese individuals ( P =0.02). The vasorelaxing response to canagliflozin was not modified ( P =0.93) by inhibition of nitric oxide synthase (L-NAME) or prostacyclin (indomethacin), or by H 2 O 2 scavenging (catalase); also, canagliflozin-induced relaxation was similar ( P =0.23) in endothelium-intact or -denuded arteries precontracted with high potassium concentration, thereby excluding an involvement of endothelium-derived hyperpolarizing factors. The vasorelaxing response to canagliflozin was similar to that elicited by the Na + /H + exchanger 1 inhibitor BIX ( P =0.67), but greater than that to the Na + /Ca ++ exchanger inhibitor SEA 0400 ( P =0.001), hinting a role of Na + /H + exchanger inhibition in canagliflozin-induced relaxation. In arterioles from obese patients, the vasorelaxing response to canagliflozin was greater than that to liraglutide ( P =0.004). These findings demonstrate that canagliflozin induces endothelium-independent vasorelaxation in arterioles from human visceral adipose tissue, thereby suggesting that SGLT2 inhibition might favorably impact the processes linking visceral adipose burden to vascular disease in obesity.


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