Molecular and morphologic characterization of superficial‐ and deep‐subcutaneous adipose tissue subdivisions in human obesity

Abstract

Objective: Human abdominal subcutaneous white adipose tissue (SAT) is composed of two different subcompartments: a ''superficial'' SAT (SSAT), located between the skin and a fibrous-fascia plane; and a deeper SAT, located under this fibrous fascia plane, indicated as ''deep'' SAT (DSAT). Design and Methods: In order to investigate whether SSAT and DSAT have different molecular and morphological features, paired SSAT/DSAT biopsies were collected from 10 female obese patients and used for microarray and morphologic analysis. The stroma-vascular fraction cells were also isolated from both depots and cultured in vitro to assess the lipid accumulation rate. Results: SSAT and DSAT displayed different patterns of gene expression, mainly for metabolic and inflammatory genes, respectively. Detailed gene expression analysis indicated that several metabolic genes, including adiponectin, are preferentially expressed in SSAT, whereas inflammatory genes are overexpressed in DSAT. Despite a similar lipid accumulation rate in vitro, in vivo SSAT showed a significant adipocyte hypertrophy together with a significantly lower inflammatory infiltration and vascular vessel lumen mean size, when compared to DSAT. Conclusions: These data show that, SSAT and DSAT are functionally and morphologically different and emphasize the importance of considering independent these two adipose depots when investigating SAT biology and obesity complications.

Anatomical, Histological And Metabolic Differences Between Hypodermis And Subcutaneous Adipose Tissue

“…Adipose stem cells have drawn the attention of researchers over the past 15 years due to the following factors: harvesting these cells has been made easily through liposuction approaches [11]; they form an important regenerating tissue; they represent a possible regulator of obesity owing to their secreting capacity [15].…”

“…Cancello et al also described a specific role of the subcutaneous adipose tissue (LAT) in hepatic complications secondary to obesity, like nonalcoholic steatohepatitis (NASH). By contrast, the researchers highlight the fact that kidney diseases are probably associated with protein genes expressed in the hypodermis (AAT) [11].…”

“…On the other hand, the subcutaneous adipose tissue (LAT) has an important inflammatory profile due to the more significant inflammatory cell infiltration [7]. Recent studies reveal that in morbidly obese patients the inflammation level in the subcutaneous adipose tissue (LAT) is related to the severity of hepatic diseases [11].…”

“…Regarding the abdominal adipose tissue metabolism, the amount of subcutaneous adipose tissue (SAT) is highly correlated with fasting insulin, especially in men [11]. Differences in lipogenic and lipolytic activities are suggested due to the fact that some studies demonstrated a thermal insulation role of the hypodermis (AAT) and a metabolic role of the subcutaneous adipose tissue (LAT) in swines [11].…”

“…Differences in lipogenic and lipolytic activities are suggested due to the fact that some studies demonstrated a thermal insulation role of the hypodermis (AAT) and a metabolic role of the subcutaneous adipose tissue (LAT) in swines [11]. Cancello et al also described a specific role of the subcutaneous adipose tissue (LAT) in hepatic complications secondary to obesity, like nonalcoholic steatohepatitis (NASH).…”