Secretion of adipokines by human adipose tissue in vivo: partitioning between capillary and lymphatic transport

2011 ◽  
Vol 301 (4) ◽  
pp. E659-E667 ◽  
Author(s):  
Norman E. Miller ◽  
C. Charles Michel ◽  
M. Nazeem Nanjee ◽  
Waldemar L. Olszewski ◽  
Irina P. Miller ◽  
...  

Peptides secreted by adipose tissue (adipokines) may enter blood via capillaries or lymph. The relative importance of these pathways for a given adipokine might influence its biological effects. Because this has not been studied in any species, we measured the concentrations of seven adipokines and eight nonsecreted proteins in afferent peripheral lymph and venous plasma from 12 healthy men. Data for nonsecreted proteins were used to derive indices of microvascular permeability, which in conjunction with the molecular radii of the adipokines were used to estimate the amounts leaving the tissue via capillaries. Transport rates via lymph were estimated from the lymph adipokine concentrations and lymph flow rates and total transport (secretion) as the sum of this and capillary transport. Concentrations of nonsecreted proteins were always lower in lymph than in plasma. With the exception of adiponectin, adipokine concentrations were always higher in lymph ( P < 0.01). Leptin and MCP-1 were secreted at the highest rates (means: 43 μg/h or 2.7 nmol/h and 32 μg/h or 2.4 nmol/h, respectively). IL-6 and MCP-1 secretion rates varied greatly between subjects. The proportion of an adipokine transported via lymph was directly related to its molecular radius ( r s = +0.94, P = 0.025, n = 6), increasing from 14 to 100% as the radius increased from 1.18 (IL-8) to 3.24 nm (TNFα). We conclude that the lymph/capillary partitioning of adipokines is a function of molecular size, which may affect both their regional and systemic effects in vivo. This finding may have implications for the physiology of peptides secreted by other tissues.

2021 ◽  
Vol 22 (15) ◽  
pp. 7920
Author(s):  
Myroslava Mytsyk ◽  
Giulia Cerino ◽  
Gregory Reid ◽  
Laia Gili Sole ◽  
Friedrich S. Eckstein ◽  
...  

The therapeutic potential of mesenchymal stromal/stem cells (MSC) for treating cardiac ischemia strongly depends on their paracrine-mediated effects and their engraftment capacity in a hostile environment such as the infarcted myocardium. Adipose tissue-derived stromal vascular fraction (SVF) cells are a mixed population composed mainly of MSC and vascular cells, well known for their high angiogenic potential. A previous study showed that the angiogenic potential of SVF cells was further increased following their in vitro organization in an engineered tissue (patch) after perfusion-based bioreactor culture. This study aimed to investigate the possible changes in the cellular SVF composition, in vivo angiogenic potential, as well as engraftment capability upon in vitro culture in harsh hypoxia conditions. This mimics the possible delayed vascularization of the patch upon implantation in a low perfused myocardium. To this purpose, human SVF cells were seeded on a collagen sponge, cultured for 5 days in a perfusion-based bioreactor under normoxia or hypoxia (21% and <1% of oxygen tension, respectively) and subcutaneously implanted in nude rats for 3 and 28 days. Compared to ambient condition culture, hypoxic tension did not alter the SVF composition in vitro, showing similar numbers of MSC as well as endothelial and mural cells. Nevertheless, in vitro hypoxic culture significantly increased the release of vascular endothelial growth factor (p < 0.001) and the number of proliferating cells (p < 0.00001). Moreover, compared to ambient oxygen culture, exposure to hypoxia significantly enhanced the vessel length density in the engineered tissues following 28 days of implantation. The number of human cells and human proliferating cells in hypoxia-cultured constructs was also significantly increased after 3 and 28 days in vivo, compared to normoxia. These findings show that a possible in vivo delay in oxygen supply might not impair the vascularization potential of SVF- patches, which qualifies them for evaluation in a myocardial ischemia model.


Gut ◽  
2008 ◽  
Vol 58 (4) ◽  
pp. 570-581 ◽  
Author(s):  
H Aurich ◽  
M Sgodda ◽  
P Kaltwasser ◽  
M Vetter ◽  
A Weise ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1378
Author(s):  
Peyton Gibler ◽  
Jeffrey Gimble ◽  
Katie Hamel ◽  
Emma Rogers ◽  
Michael Henderson ◽  
...  

Human adipose-derived stromal/stem cells (hASC) are widely used for in vitro modeling of physiologically relevant human adipose tissue. These models are useful for the development of tissue constructs for soft tissue regeneration and 3-dimensional (3D) microphysiological systems (MPS) for drug discovery. In this systematic review, we report on the current state of hASC culture and assessment methods for adipose tissue engineering using 3D MPS. Our search efforts resulted in the identification of 184 independent records, of which 27 were determined to be most relevant to the goals of the present review. Our results demonstrate a lack of consensus on methods for hASC culture and assessment for the production of physiologically relevant in vitro models of human adipose tissue. Few studies have assessed the impact of different 3D culture conditions on hASC adipogenesis. Additionally, there has been a limited use of assays for characterizing the functionality of adipose tissue in vitro. Results from this study suggest the need for more standardized culture methods and further analysis on in vitro tissue functionality. These will be necessary to validate the utility of 3D MPS as an in vitro model to reduce, refine, and replace in vivo experiments in the drug discovery regulatory process.


Endocrinology ◽  
2003 ◽  
Vol 144 (12) ◽  
pp. 5578-5584 ◽  
Author(s):  
Philippe Linscheid ◽  
Dalma Seboek ◽  
Eric S. Nylen ◽  
Igor Langer ◽  
Mirjam Schlatter ◽  
...  

1999 ◽  
Vol 277 (3) ◽  
pp. E474-E480 ◽  
Author(s):  
Ian Murray ◽  
Allan D. Sniderman ◽  
Katherine Cianflone

Acylation stimulating protein (ASP), a novel adipocyte-derived autocrine protein, stimulates triglyceride synthesis and glucose transport in vitro in human and murine adipocytes. In vitro, chylomicrons increase ASP and precursor complement C3 production in adipocytes. Furthermore, in vivo, ASP production from human adipose tissue correlates positively with triglyceride clearance postprandially. The aim of the present study was to determine if intraperitoneally injected ASP accelerated triglyceride clearance in vivo after a fat load in C57Bl/6 mice. ASP increased the triglyceride clearance with a reduction of the triglyceride area under the curve over 6 h (AUC0–6) from 102.6 ± 30.0 to 61.0 ± 14.5 mg ⋅ dl−1 ⋅ h−1( P < 0.05), especially in the latter postprandial period (AUC3–6; 56.2 ± 18.0 vs. 24.9 ± 8.9 mg ⋅ dl−1 ⋅ h−1, P < 0.025). ASP also reduced plasma glucose both in the mice with accelerated plasma triglyceride clearance and in those with relatively delayed triglyceride clearance ( P < 0.025). Therefore, ASP alters postprandial triglyceride and glucose metabolism.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Koji Hanai ◽  
Takashi Kojima ◽  
Mika Ota ◽  
Jun Onodera ◽  
Norimasa Sawada

Atelocollagen is a major animal protein that is used as a highly biocompatible biomaterial. To date, atelocollagen has been used as an effective drug delivery technology to sustain the release of antitumor proteins and to enhance the antitumor activity of oligonucleotides in in vivo models. However, the biological effects of this technology are not fully understood. In the present study, we investigated the effects of atelocollagen on endothelial paracellular barrier function. An atelocollagen formulation containing oligonucleotides specifically increased the permeability of two types of endothelial cells, and the change was dependent on the molecular size, structure of the oligonucleotides used and the concentrations of the oligonucleotide and atelocollagen in the formulation. An immunohistochemical examination revealed that the formulation had effects on the cellular skeleton and intercellular structure although it did not affect the expression of adherens junction or tight junction proteins. These changes were induced through p38 MAP kinase signaling. It is important to elucidate the biological functions of atelocollagen in order to be able to exploit its drug delivery properties.


1993 ◽  
Vol 84 (4) ◽  
pp. 477-482 ◽  
Author(s):  
Brian W. Morris ◽  
Trevor A. Gray ◽  
Sheila MacNeil

1. This study was designed to investigate the influence of insulin and glucose on the distribution of trivalent chromium in human plasma and blood cells and in human and rat insulin-sensitive and -insensitive tissues. 2. Evidence is provided that, in the rat in vitro, a clear difference exists in chromium binding between insulin-sensitive and -insensitive tissues in that chromium binding is significantly enhanced by glucose in insulin-sensitive tissues. 3. Glucose-dependent association of chromium with human adipose tissue was blocked by inhibitors of glucose transport. 4. Addition of insulin slightly increased the response to glucose in muscle and reduced the response to glucose in adipose tissue; such effects were less marked than those seen in response to glucose alone. 5. The results of this study in vitro support the hypothesis that, in vivo, chromium translocates from the blood compartment to insulin-sensitive tissues.


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