Lipomatosis-associated inflammation and excess collagen may contribute to lower relative resting energy expenditure in women with adiposis dolorosa.

BACKGROUND: Adiposis dolorosa (AD) is a syndrome of obese and non-obese individuals whose hallmark is lipomatosis: unencapsulated painful fatty masses in subcutaneous fat. Lipomatosis may contain excess collagen and multi-nucleated giant (MNG) cells. Case reports suggest metabolic defects in AD.

OBJECTIVES: (1) To determine whether women with AD have altered relative resting energy expenditure (REE per total body mass) compared with controls; and (2) to quantitate lipomatosis-associated collagen, MNGs and tissue and blood cytokines that may influence REE.

METHODS: A total of 10 women with AD were compared with age, body mass index, fat and weight-matched control women. Adipose tissue was obtained from five women with AD and five controls and evaluated for collagen and macrophages/MNGs. Fat mass and fat-free mass were identified by dual X-ray absorptiometry. REE was by determined indirect calorimetry and related to mass. Adipokines and cytokines were evaluated in blood and tissue.

RESULTS: Relative REE (REE per total body mass) was lower in women with AD compared with controls (P=0.007). Only lipomatosis (group) and total body mass were significant predictors of REE in forward stepwise regression (P<0.0001). Adipose interleukin (IL)-6 levels were elevated (P=0.03) and connective tissue was increased fourfold in lipomatosis compared with control tissue (P <0.0001). There was no difference in adipose tissue macrophages between groups; 30% of women with AD had MNG cells. Anti-inflammatory IL-13 levels were elevated (P=0.03), and cytokines important in the recruitment of monocytes, Fraktalkine (P=0.04) and macrophage inflammatory protein-1beta (P=0.009), were significantly lower in the blood of women with AD compared with controls.

CONCLUSIONS: The lower relative REE in women with AD compared with controls was associated with increased connective (non-metabolic) tissue in the lipomatosis, and inflammation, although underlying metabolic defects may be important as well. Understanding the pathophysiology and metabolism of lipomatosis in AD may contribute to a better understanding of metabolism in non-lipomatosis obesity.