FTIR imaging of structural changes in visceral and subcutaneous adiposity and brown to white adipocyte transdifferentiation

Abstract

Obesity is a heterogeneous disorder which increases risks for multiple metabolic diseases, such as type 2 diabetes. The current study aims to characterize and compare visceral and subcutaneous adipose tissues in terms of macromolecular content and investigate transdifferentiation between white and brown adipocytes. Regarding this aim, Fourier transform infrared (FTIR) microspectroscopy and uncoupling protein 1 (UCP1) immunohistological staining were used to investigate gonadal (visceral) and inguinal (subcutaneous) adipose tissues of male Berlin fat mice inbred (BFMI) lines, which are spontaneously obese. The results indicated a remarkable increase in the lipid/protein ratio, accompanied with a decrease of UCP1 protein content which might be due to the transdifferentiation of brown adipocytes to white adipocytes in obese groups. It has been widely reported that brown adipose tissue has a strong effect on fatty acid and glucose homeostasis and it could provide an opportunity for the therapy of obesity. When the amount of brown adipose tissue was decreased, lower unsaturation/saturation ratio, qualitatively longer hydrocarbon acyl chain length of lipids and higher amount of triglycerides were obtained in both adipose tissues of mice lines. The results also revealed that subcutaneous adipose tissue was more prone to obesity-induced structural changes than visceral adipose tissue, which could originate from it possessing a lower amount of brown adipose tissue. The current study clearly revealed the power of FTIR microspectroscopy in the precise determination of obesity-induced structural and functional changes in inguinal and gonadal adipose tissue of mice lines.

Aspects of silver tolerance in bacteria: infrared spectral changes and epigenetic clues

“…The significant decrease in the intensities of amide I band (Table 1) evidenced a decrease in protein concentrations [9]. The shift in the positions of amide I band to higher values in the Ag-exposed bacteria ( Table 1) demonstrated the structural alterations in proteins [15]. The decreased protein content in Cd-and Pb-exposed bacteria that we measured in our previous study is in agreement with the results of this study [8].…”

“…This region contains several spectral bands arising mostly from lipid functional groups along with small contributions from protein [8,14]. As can be seen from Table 1, the intensity of this band increased significantly in the Ag-exposed bacteria evidencing elevated lipid content [15]. As can be seen from Table 1, the intensity of this band increased significantly in the Ag-exposed bacteria evidencing elevated lipid content [15].…”

“…To define changes of the lipid content due to Ag adaptation, the intensity of the CH 2 antisymmetric band located at 2924 cm −1 emerging from antisymmetric stretching vibrations of the functional groups in lipid was measured. As can be seen from Table 1, the intensity of this band increased significantly in the Ag-exposed bacteria evidencing elevated lipid content [15]. The elevated lipid concentrations indicate an alteration in lipid metabolism [9,16].…”

Activation of Macrophages by CpG DNA and LPS: an FTIR Spectroscopic Study

“…ATR-FTIR spectroscopy has multiple applications in hematology and was used in the analysis of live cell activation [6,7], the screening of numerous diseases [8][9][10][11], the response of cells to chemical stress [12], the identification of disease states in the early stages [13][14][15] and cellular differentiation [16].…”

Quantifying Biochemical Alterations in Brown and Subcutaneous White Adipose Tissues of Mice Using Fourier Transform Infrared Widefield Imaging

“…The potential of FTIR imaging to measure intact tissues (23, 24) and living cells (25–28) without applying exogenous labels has been thoroughly studied. FTIR imaging has been previously used by obesity researchers to quantify the fatty acid composition of human abdominal fat (29), as well as obesity-induced alterations in liver and muscle tissues in BXD recombinant inbred mice (30), determination of the lipid profile of liver tissue (31), and obesity-induced alterations in subcutaneous and visceral adipose tissues (32). To our knowledge, none of these prior works demonstrate that FTIR imaging is capable of detecting biochemical changes to the BAT and s-WAT caused by cold exposure.…”