[Anatomical heterogeneity in the proteome of human subcutaneous adipose tissue]

Abstract

Background: Human subcutaneous (SQ) white adipose tissue (WAT) can vary according to its anatomical location, with subsequent differences in its proteomic profile.

Patients and methods: SQ-WAT aspirates were obtained from six overweight (BMI>25kg/m(2)) women who underwent extensive liposuction. SQ-WAT was removed from six different locations (upper abdominal, lower abdominal, thigh, back, flank, and hip), and the protein profiles were determined by two-dimensional gel electrophoresis. In addition, the proteomic profiles of upper abdominal and hip SQ-WAT were subjected to further analysis, comparing samples obtained from two layers of WAT (deep and superficial).

Results: Twenty one protein spots showed differential intensities among the six defined anatomical locations, and 14 between the superficial and the deep layer. Among the proteins identified were, vimentin (structural protein), heat-shock proteins (HSPs), superoxide-dismutase (stress-resistance/chaperones), fatty-acid-binding protein (FABP) 4, and alpha-enolase (lipid and carbohydrate metabolism), and ATP-synthase (energy production). Among the WAT samples analyzed, the back sub-depot showed significant differences in the levels of selected proteins when compared to the other locations, with lower level of expression of several proteins involved in energy production and metabolism (ATP-synthase, alpha-enolase, HSPs and FABP-4).

Conclusions: The levels of several proteins in human SQ-WAT are not homogeneous between different WAT depots. These changes suggest the existence of inherent functional differences in subcutaneous fat depending upon its anatomical location. Thus, caution must be used when extrapolating data from one subcutaneous WAT region to other depots.

Figura 1

Localizaciones anatómicas definidas para la obtención de muestras: Abdominal superior (entre la línea umbilical y la costilla inferior), abdominal inferior (entre la línea umbilical y el pliegue abdominal), muslo, cadera (entre la cresta ilíaca y la costilla inferior), flanco (entre la Costilla inferior y la línea escapular) y dorsal (por encima de la línea escapular).

Figura 2

Muestra de geles de electroforesis bidimensional. Se resaltan las potenciales proteínas que exhibían diferente intensidad en la comparación entre las capas superficial y profunda del TAB-Sc en los “sub-depósitos” abdominal superior (A) y cadera (B).

Figura 3

Muestra de gel de electroforesis bidimensional. Se resaltan las potenciales proteínas que exhibían diferente intensidad en la comparación entre los distintos “sub-depósitos” definidos de acuerdo con su localización anatómica.

Figura 4

Los diagramas representan el nivel de expresión (media ± DE) de las proteínas identificadas en cada uno de los “sub-depósitos” de tejido adiposo blanco subcutáneo definidos. Los asteriscos en la línea superior reflejan el nivel de significación de la comparación entre todos los depósitos. Las líneas inferiores con asteriscos muestran los resultados de los análisis “post-hoc”, entre parejas de “sub-depósitos”. *: p<0,05; ** p<0,01. Abreviaturas: A-I: abdominal inferior; A-S: abdominal superior; C: cadera; D: dorsal; F: flanco; M: muslo.