scholarly journals The Effects of Mild Intermittent Hypoxia Exposure on the Abdominal Subcutaneous Adipose Tissue Proteome in Overweight and Obese Men: A First-in-Human Randomized, Single-Blind, and Cross-Over Study

2022 ◽  
Vol 12 ◽  
Author(s):  
Rens L. J. Van Meijel ◽  
Ping Wang ◽  
Freek Bouwman ◽  
Ellen E. Blaak ◽  
Edwin C. M. Mariman ◽  
...  

Adipose tissue (AT) oxygen tension (pO2) has been implicated in AT dysfunction and metabolic perturbations in both rodents and humans. Compelling evidence suggests that hypoxia exposure alters metabolism, at least partly through effects on AT. However, it remains to be elucidated whether mild intermittent hypoxia (MIH) exposure impacts the AT proteome. We performed a randomized, single-blind, and cross-over study to investigate the effects of seven consecutive days of MIH (FiO2 15%, 3x2h/d) compared to normoxia (FiO2 21%) exposure on the AT proteome in overweight/obese men. In vivo AT insulin sensitivity was determined by the gold standard hyperinsulinemic-euglycemic clamp, and abdominal subcutaneous AT biopsies were collected under normoxic fasting conditions following both exposure regimens (day 8). AT proteins were isolated and quantified using liquid chromatography-mass spectrometry. After correction for blood contamination, 1,022 AT protein IDs were identified, of which 123 were differentially expressed following MIH (p < 0.05). We demonstrate for the first time that MIH exposure, which markedly reduces in vivo AT oxygen tension, impacts the human AT proteome. Although we cannot exclude that a single differentially expressed protein might be a false positive finding, several functional pathways were altered by MIH exposure, also after adjustment for multiple testing. Specifically, differentially expressed proteins were involved in redox systems, cell-adhesion, actin cytoskeleton organization, extracellular matrix composition, and energy metabolism. The MIH-induced change in AT TMOD3 expression was strongly related to altered in vivo AT insulin sensitivity, thus linking MIH-induced effects on the AT proteome to metabolic changes in overweight/obese humans.

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Zeljko Bosnjak ◽  
Bassam Wakim ◽  
Yasheng Yan ◽  
Scott Canfield ◽  
Chika Kikuchi ◽  
...  

Growing evidence from animal studies shows that adipose tissue-derived stem cells (ASCs) improve cardiac function of infarcted hearts. It is commonly accepted that therapeutic potential of ASCs may depend more on their paracrine effects than differentiation potential. The underlying mechanisms remain unclear. However, most data regarding paracrine factors were obtained from ASCs cultured in normoxic condition (20%). The present study investigated how in vivo physiological oxygen (4%) tension influenced the secretome of ASCs. ASCs were isolated from three 8-week-old BALB/c mice. ASCs were confirmed by the expression of stem cell markers (CD44 and CD90) and their capacity to differentiate into adipocytes and osteocytes. ASCs at passage 5 were cultured in normoxic (20%) and lower oxygen (4%) incubators and conditioned for 24 h (3 cultures/group). The conditioned media (CM) from ASCs were subjected to trypsin digestion followed by analysis using automated nano-flow liquid chromatography tandem mass spectrometry. The collected LC/MS/MS data were searched against the rodent subset of the Uniprot database and the total proteomes were identified. The data were from 6 technical replicates. A total of 28 proteins were identified and 7 proteins were unique to normoxic CM. Of the 21 common proteins detected in both normoxic and lower oxygen CM, 9 were extracellular matrix proteins. The abundance of 6 of these proteins (e.g., collagen I and laminin) differed noticeably between normoxic and lower oxygen CM. In addition, a greater amount of cytokine CXCL5 and matrix metalloproteinase (MMP)-2 was detected in lower oxygen CM than in normoxic CM while tissue inhibitor of metalloproteinase (TIMP)-1 was only detected in normoxic CM. These results indicate that lower oxygen tension differentially regulates the secretome of ASCs. Extrapolating the results of this study to the in vivo setting, it would appear that injected ASCs may exert their anti-fibrotic and trophic effect by 1) directly regulating the balance of MMP/TIMP production and preventing collagen accumulation in ischemic hearts to decrease fibrosis, and 2) secreting trophic factors including CXCL5. These data suggest that proteomic analysis of CM is useful for elucidation of the paracrine effect of ASCs in vivo.


Nutrients ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1829 ◽  
Author(s):  
Lepore ◽  
Maggisano ◽  
Bulotta ◽  
Mignogna ◽  
Arcidiacono ◽  
...  

Oleacein is one of the most abundant polyphenolic compounds of olive oil, which has been shown to play a protective role against several metabolic abnormalities, including dyslipidemia, insulin resistance, and glucose intolerance. Herein, we investigated the effects of oleacein on certain markers of adipogenesis and insulin-resistance in vitro, in 3T3-L1 adipocytes, and in vivo in high-fat diet (HFD)-fed mice. During the differentiation process of 3T3-L1 preadipocytes into adipocytes, oleacein strongly inhibited lipid accumulation, and decreased protein levels of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid synthase (FAS), while increasing Adiponectin levels. In vivo, treatment with oleacein of C57BL/6JOlaHsd mice fed with HFD for 5 and 13 weeks prevented the increase in adipocyte size and reduced the inflammatory infiltration of macrophages and lymphocytes in adipose tissue. These effects were accompanied by changes in the expression of adipose tissue-specific regulatory elements such as PPARγ, FAS, sterol regulatory element-binding transcription factor-1 (SREBP-1), and Adiponectin, while the expression of insulin-sensitive muscle/fat glucose transporter Glut-4 was restored in HFD-fed mice treated with oleacein. Collectively, our findings indicate that protection against HFD-induced adiposity by oleacein in mice is mediated by the modulation of regulators of adipogenesis. Protection against HFD-induced obesity is effective in improving peripheral insulin sensitivity.


Endocrinology ◽  
2020 ◽  
Vol 161 (10) ◽  
Author(s):  
Jonathan H Kahn ◽  
Anna Goddi ◽  
Aishwarya Sharma ◽  
Joshua Heiman ◽  
Alanis Carmona ◽  
...  

Abstract The Silencing Mediator of Retinoid and Thyroid Hormone Receptors (SMRT) is a nuclear corepressor, regulating the transcriptional activity of many transcription factors critical for metabolic processes. While the importance of the role of SMRT in the adipocyte has been well-established, our comprehensive understanding of its in vivo function in the context of homeostatic maintenance is limited due to contradictory phenotypes yielded by prior generalized knockout mouse models. Multiple such models agree that SMRT deficiency leads to increased adiposity, although the effects of SMRT loss on glucose tolerance and insulin sensitivity have been variable. We therefore generated an adipocyte-specific SMRT knockout (adSMRT-/-) mouse to more clearly define the metabolic contributions of SMRT. In doing so, we found that SMRT deletion in the adipocyte does not cause obesity—even when mice are challenged with a high-fat diet. This suggests that adiposity phenotypes of previously described models were due to effects of SMRT loss beyond the adipocyte. However, an adipocyte-specific SMRT deficiency still led to dramatic effects on systemic glucose tolerance and adipocyte insulin sensitivity, impairing both. This metabolically deleterious outcome was coupled with a surprising immune phenotype, wherein most genes differentially expressed in the adipose tissue of adSMRT-/- mice were upregulated in pro-inflammatory pathways. Flow cytometry and conditioned media experiments demonstrated that secreted factors from knockout adipose tissue strongly informed resident macrophages to develop a pro-inflammatory, MMe (metabolically activated) phenotype. Together, these studies suggest a novel role for SMRT as an integrator of metabolic and inflammatory signals to maintain physiological homeostasis.


Biochimie ◽  
2005 ◽  
Vol 87 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Claire Lagathu ◽  
Minji Kim ◽  
Mustapha Maachi ◽  
Corinne Vigouroux ◽  
Pascale Cervera ◽  
...  

Metabolism ◽  
1993 ◽  
Vol 42 (9) ◽  
pp. 1195-1200 ◽  
Author(s):  
William G. Blackard ◽  
John N. Clore ◽  
Penny S. Glickman ◽  
John E. Nestler ◽  
John M. Kellum

2003 ◽  
Vol 285 (3) ◽  
pp. E527-E533 ◽  
Author(s):  
Jens M. Bruun ◽  
Aina S. Lihn ◽  
Camilla Verdich ◽  
Steen B. Pedersen ◽  
Søren Toubro ◽  
...  

Adiponectin is an adipose tissue-specific protein that is abundantly present in the circulation and suggested to be involved in insulin sensitivity and development of atherosclerosis. Because cytokines are suggested to regulate adiponectin, the aim of the present study was to investigate the interaction between adiponectin and three adipose tissue-derived cytokines (IL-6, IL-8, and TNF-α). The study was divided into three substudies as follows: 1) plasma adiponectin and mRNA levels in adipose tissue biopsies from obese subjects [mean body mass index (BMI): 39.7 kg/m2, n = 6] before and after weight loss; 2) plasma adiponectin in obese men (mean BMI: 38.7 kg/m2, n = 19) compared with lean men (mean BMI: 23.4 kg/m2, n = 10) before and after weight loss; and 3) in vitro direct effects of IL-6, IL-8, and TNF-α on adiponectin mRNA levels in adipose tissue cultures. The results were that 1) weight loss resulted in a 51% ( P < 0.05) increase in plasma adiponectin and a 45% ( P < 0.05) increase in adipose tissue mRNA levels; 2) plasma adiponectin was 53% ( P < 0.01) higher in lean compared with obese men, and plasma adiponectin was inversely correlated with adiposity, insulin sensitivity, and IL-6; and 3) TNF-α ( P < 0.01) and IL-6 plus its soluble receptor ( P < 0.05) decreased adiponectin mRNA levels in vitro. The inverse relationship between plasma adiponectin and cytokines in vivo and the cytokine-induced reduction in adiponectin mRNA in vitro suggests that endogenous cytokines may inhibit adiponectin. This could be of importance for the association between cytokines (e.g., IL-6) and insulin resistance and atherosclerosis.


2016 ◽  
Vol 64 (5) ◽  
pp. 989-991 ◽  
Author(s):  
Esben Søndergaard ◽  
Michael D Jensen

In metabolically healthy humans, adipose tissue is exquisitely sensitive to insulin. Similar to muscle and liver, adipose tissue lipolysis is insulin resistant in adults with central obesity and type 2 diabetes. Perhaps uniquely, however, insulin resistance in adipose tissue may directly contribute to development of insulin resistance in muscle and liver because of the increased delivery of free fatty acids to those tissues. It has been hypothesized that insulin adipose tissue resistance may precede other metabolic defects in obesity and type 2 diabetes. Therefore, precise and reproducible quantification of adipose tissue insulin sensitivity, in vivo, in humans, is an important measure. Unfortunately, no consensus exists on how to determine adipose tissue insulin sensitivity. We review the methods available to quantitate adipose tissue insulin sensitivity and will discuss their strengths and weaknesses.


2013 ◽  
Vol 11 (4) ◽  
pp. 193-193
Author(s):  
Rick I. Meijer ◽  
Michiel P. de Boer ◽  
Etto C. Eringa ◽  
Donald L. van der Peet ◽  
Erik van Poelgeest ◽  
...  

2021 ◽  
Vol 22 (11) ◽  
pp. 5604
Author(s):  
David Sanz-Rubio ◽  
Abdelnaby Khalyfa ◽  
Zhuanhong Qiao ◽  
Jorge Ullate ◽  
José M. Marin ◽  
...  

Intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), is associated with cardiovascular and metabolic dysfunction. However, the mechanisms underlying these morbidities remain poorly delineated. Extracellular vesicles (EVs) mediate intercellular communications, play pivotal roles in a multitude of physiological and pathological processes, and could mediate IH-induced cellular effects. Here, the effects of IH on human primary cells and the release of EVs were examined. Microvascular endothelial cells (HMVEC-d), THP1 monocytes, THP1 macrophages M0, THP1 macrophages M1, THP1 macrophages M2, pre-adipocytes, and differentiated adipocytes (HAd) were exposed to either room air (RA) or IH for 24 h. Secreted EVs were isolated and characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. The effects of each of the cell-derived EVs on endothelial cell (EC) monolayer barrier integrity, on naïve THP1 macrophage polarity, and on adipocyte insulin sensitivity were also evaluated. IH did not alter EVs cell quantal release, but IH-EVs derived from HMVEC-d (p < 0.01), THP1 M0 (p < 0.01) and HAd (p < 0.05) significantly disrupted HMVEC-d monolayer integrity, particularly after H2O2 pre-conditioning. IH-EVs from HMVEC-d and THP1 M0 elicited M2-polarity changes did not alter insulin sensitivity responses. IH induces cell-selective changes in EVs cargo, which primarily seem to target the emergence of endothelial dysfunction. Thus, changes in EVs cargo from selected cell sources in vivo may play causal roles in some of the adverse outcomes associated with OSA.


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