Multiple Symmetric Lipomatosis: Substantial Subcutaneous Adipose Tissue Accumulation Did Not Induce Glucose and Lipid Metabolism Dysfunction

OBJECTIVE: To study whether substantial subcutaneous adipose tissue (SCAT) can induce glucose and lipid metabolism dysfunction and possible underlying mechanisms. METHODS: We report a male patient with multiple symmetrical lipomatosis (MSL) suffering from increased adipose tissue accumulation in abdomen and back for 7 years, accompanied by the gradual expansion of excess adipose tissue to the nuchal region, upper thorax, upper arms and shoulders. Four obese male adults of similar age and body mass index were chosen as controls (only 4 subjects consented to blood and tissue sampling).Blood samples were collected before anesthesia in the early morning after overnight fasting, and tissue samples from all subjects and the patient were obtained under general anesthesia. Glucose tolerance, insulin resistance in the oral glucose tolerance test and insulin-releasing test were studied. A pathologic examination was made and expression of SCAT-related genes was determined. RESULTS: Although adipose tissue mainly accumulated in SCAT, the patient had no impaired glucose tolerance, insulin resistance and dyslipidemia. Importantly, the circulating adiponectin concentration was higher than in the control group (50.3 +/- 3.2 vs. 28.4 +/- 2.2 microg/ml, p < 0.05). Accordingly, adiponectin and leptin mRNA expression in SCAT was higher than in the control group (1.83 and 3.75 times, p < 0.05) but TNF-alpha and IL-6 mRNA levels were lower (decreased by 79 and 45%, p < 0.05). Furthermore, pathologically, adipocyte size in the patient's SCAT was smaller than in the control group (66.2 +/- 6.1 vs. 78.9 +/- 6.6 and 98.6 +/- 12.8 microm in SCAT and omentum adipose tissue, respectively, p < 0.05). CONCLUSION: In spite of the patient's SCAT accumulation, glucose and lipid metabolism dysfunction was absent. The mechanism may involve the interaction of different factors, including the subcutaneous formation of small adipocytes, the secretion of protective adipokines such as adiponectin and anti-inflammatory effects of SCAT.