PubMed · 7342299
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M C De Almeida, L F Assumpção, I Pfeferman, R C Martins, N F Safatle. [Lumbar hernia].. https://pubmed.ncbi.nlm.nih.gov/7342299/
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Decellularized tissues provide biological cues owing to the wealth of structural and regulatory factors that promote angiogenesis, adipogenesis, and myogenesis and facilitate neurite outgrowth. Here, we demonstrated the advantages of decellularized adipose tissue (adipoECM) over defined collagen-based biomaterials for host tissue integration. Three batches of human adipose tissue were decellularized using a rapid decellularization protocol and analyzed using mass spectrometry. To assess the biological activity of the decellularized materials, adipoECM and a reference standard of care biomaterial (Integra®DRT, also containing collagen I and glycosaminoglycans) were implanted subcutaneously, but far from the wound bed (in anatomical potential spaces) of immunocompetent BALB/c mice. The mice were euthanized in the acute (1 day) and chronic (day 60) inflammatory reaction phases, followed by biomaterial excision and Masson’s trichrome immunohistofluorescence imaging of the paraffin-embedded specimens. Each batch of processed tissue passed a quality control check, showing a low level of donor genomic DNA, lack of nuclei, lipids, endotoxins, and bacterial contamination. Mass spectrometry revealed that all batches of decellularized tissue mainly contained collagen I and, to a lesser degree, collagen III, collagen IV, collagen V, laminin, fibrillin, fibronectin, tenascin, and elastin. No acute inflammatory reaction was observed in either material one day post-transplantation. At 60 days post-implantation, different cell types were detected in adipoECM specimens, whereas Integra®DRT remained acellular. Additional immunohistochemical staining of adipoECM revealed CD31-positive cells in the blood vessels. Mesenchymal (CD90 positive) and myeloid (CD14 positive) cells were also detected. Primary cell types involved in soft tissue healing and remodeling were found in the adipoECM-treated group. The ingrowth of blood vessels and mesenchymal cells confirmed the effective integration of adipoECM with host tissues. Our results demonstrate that decellularized adipose tissue implanted away from the wound bed possesses contextual biological activities that promote efficient integration with host tissues.
We used microdialysis to distinguish the effects of hyperinsulinemia and hypoglycemia on glucose, gluconeogenic substrate, and catecholamine levels in adipose and muscle extracellular fluid (ECF). Ten lean humans (six males and four females) were studied during baseline and hyperinsulinemic (3 mU x kg-1 x min-1 for 3 h) euglycemia (5.0 mmol/l) and hypoglycemia (2.8 mmol/l). In muscle and adipose, basal ECF glucose was lower (muscle, 3.5 +/- 0.2 mmol/l; adipose tissue, 3.3 +/- 0.2 mmol/l) and lactate was higher (muscle, 2.2 +/- 0.2 mmol/l; adipose, 1.5 +/- 0.3 mmol/l) than respective plasma values (glucose, 4.9 +/- 0.1 mmol/l; lactate, 0.7 +/- 0.1 mmol/l), whereas alanine was higher in muscle ECF (379 +/- 22 micromol/l) than adipose tissue (306 +/- 22 micromol/l) and plasma (273 +/- 33 micromol/l). Plasma catecholamines (unchanged during euglycemia) rose during hypoglycemia with epinephrine, increasing approximately fivefold more than norepinephrine. In contrast, the hypoglycemia-induced increments in muscle dialysate norepinephrine and epinephrine were similar, suggesting local generation of norepinephrine. Compared with euglycemia, hypoglycemia produced a greater increase in lactate and a smaller reduction in alanine in muscle ECF, whereas hypoglycemia caused a greater relative fall in ECF glucose concentrations in muscle (72 +/- 16%) and adipose tissue (69 +/- 9%) than in plasma (42 +/- 3%) (P < 0.05). We conclude that hypoglycemia increases the generation of norepinephrine and gluconeogenic substrates in key target tissues, while increasing the plasma-tissue concentration gradient for glucose. These changes suggest the stimulation of glucose extraction by peripheral tissues, despite systemic counterregulatory hormone release and local sympathetic activation.
The effects of the thiazolidinedione insulin sensitiser BRL 49653 on plasma leptin concentrations and on epididymal fat OB, PPAR-gamma and aP2 mRNA expression were examined in high-fat-fed and high-carbohydrate-fed adult Wistar rats. Diets were given for 4 weeks, with BRL 49653 (10 micromol/kg/day) administered by oral gavage for the last 4 days. Treatment with BRL 49653 reduced plasma leptin concentrations in high-fat-fed rats from 2.34 +/- 0.19 (n=9) to 1.42 +/- 0.09 (n=9) ng/ml (p<0.001). Plasma leptin was unaffected by BRL 49653 in the high-carbohydrate-fed rats. There was no difference in OB mRNA expression between high-fat-fed and high-carbohydrate-fed rats, with or without treatment. PPAR-gamma and aP2 mRNA expression were significantly increased in the high-fat-fed rats treated with BRL 49653 (p < 0.01 and p < 0.001 respectively), but not in carbohydrate-fed rats.