Liposuction does not achieve metabolic benefits of weight loss
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《英国医生杂志》
Abdominal liposuction does not significantly improve metabolic abnormalities associated with obesity, and removing adipose tissue mass alone does not achieve the metabolic benefits of weight loss, a new research report says (New England Journal of Medicine 2004;350:2549-57).
Abdominal obesity is associated with insulin resistance and other metabolic risk factors for coronary heart disease. Although both the abdominal subcutaneous fat mass and the visceral fat mass are associated with insulin resistance, it is not known whether one or both of these fat depots are actually involved in the pathogenesis of insulin resistance or whether they are simply associated with the metabolic complications of obesity.
Weight loss achieved through diet improves the metabolic complications of abdominal obesity. However, long term weight management is difficult, and most obese people who lose weight by implementing lifestyle changes regain their lost weight over time. Frustration with diets alone has led an increasing number of people to embrace quicker cosmetic fixes.
Liposuction has been often proposed as a treatment for the metabolic complications of obesity. In a study lead by Dr Samuel Klein of the Center for Human Nutrition, Washington University School of Medicine, St Louis, researchers evaluated the effect of large-volume abdominal liposuction on metabolic risk factors for coronary heart disease in women with abdominal obesity.
The researchers looked at the insulin sensitivity of liver, skeletal muscle, and adipose tissue (with a euglycaemic-hyperinsulinaemic clamp procedure and infusions of tracer isotopes) as well as levels of inflammatory mediators and other risk factors for coronary heart disease in 15 obese women before abdominal liposuction and 10 to 12 weeks afterwards. Eight of the women had normal glucose tolerance and seven had type 2 diabetes (mean body mass index 35.1 (SD 2.4) and 39.9 (5.6), respectively).
Liposuction decreased the volume of subcutaneous abdominal adipose tissue by 44% in the women with normal glucose tolerance and 28% in those with diabetes; those with normal oral glucose tolerance lost 9.1 (3.7) kg of fat (18% (3%) decrease in total fat; P=0.002), and those with type 2 diabetes lost 10.5 (3.3) kg of fat (19% (2%) decrease in total fat; P<0.001).
Liposuction did not significantly alter the insulin sensitivity of muscle, liver, or adipose tissue (assessed by the stimulation of glucose disposal, the suppression of glucose production, and the suppression of lipolysis, respectively); the procedure did not significantly alter plasma concentrations of C reactive protein, interleukin 6, tumor necrosis factor α, and adiponectin; and it did not significantly affect other risk factors for coronary heart disease (blood pressure and plasma glucose, insulin, and lipid concentrations) in either group.
In an accompanying editorial (pp 2542-3) Dr David E Kelley writes: "It remains to be determined whether the removal of an equivalent amount of visceral adipose tissue might have a more robust effect on the metabolic abnormalities of obesity.
"It may well be that a negative energy balance permits a fairly rapid improvement in fat content within liver and muscle, depots of stored energy that have been shown to affect the severity of insulin resistance, whereas the surgical removal of adipose tissue may not evoke these changes."(New York Scott Gottlieb)
Abdominal obesity is associated with insulin resistance and other metabolic risk factors for coronary heart disease. Although both the abdominal subcutaneous fat mass and the visceral fat mass are associated with insulin resistance, it is not known whether one or both of these fat depots are actually involved in the pathogenesis of insulin resistance or whether they are simply associated with the metabolic complications of obesity.
Weight loss achieved through diet improves the metabolic complications of abdominal obesity. However, long term weight management is difficult, and most obese people who lose weight by implementing lifestyle changes regain their lost weight over time. Frustration with diets alone has led an increasing number of people to embrace quicker cosmetic fixes.
Liposuction has been often proposed as a treatment for the metabolic complications of obesity. In a study lead by Dr Samuel Klein of the Center for Human Nutrition, Washington University School of Medicine, St Louis, researchers evaluated the effect of large-volume abdominal liposuction on metabolic risk factors for coronary heart disease in women with abdominal obesity.
The researchers looked at the insulin sensitivity of liver, skeletal muscle, and adipose tissue (with a euglycaemic-hyperinsulinaemic clamp procedure and infusions of tracer isotopes) as well as levels of inflammatory mediators and other risk factors for coronary heart disease in 15 obese women before abdominal liposuction and 10 to 12 weeks afterwards. Eight of the women had normal glucose tolerance and seven had type 2 diabetes (mean body mass index 35.1 (SD 2.4) and 39.9 (5.6), respectively).
Liposuction decreased the volume of subcutaneous abdominal adipose tissue by 44% in the women with normal glucose tolerance and 28% in those with diabetes; those with normal oral glucose tolerance lost 9.1 (3.7) kg of fat (18% (3%) decrease in total fat; P=0.002), and those with type 2 diabetes lost 10.5 (3.3) kg of fat (19% (2%) decrease in total fat; P<0.001).
Liposuction did not significantly alter the insulin sensitivity of muscle, liver, or adipose tissue (assessed by the stimulation of glucose disposal, the suppression of glucose production, and the suppression of lipolysis, respectively); the procedure did not significantly alter plasma concentrations of C reactive protein, interleukin 6, tumor necrosis factor α, and adiponectin; and it did not significantly affect other risk factors for coronary heart disease (blood pressure and plasma glucose, insulin, and lipid concentrations) in either group.
In an accompanying editorial (pp 2542-3) Dr David E Kelley writes: "It remains to be determined whether the removal of an equivalent amount of visceral adipose tissue might have a more robust effect on the metabolic abnormalities of obesity.
"It may well be that a negative energy balance permits a fairly rapid improvement in fat content within liver and muscle, depots of stored energy that have been shown to affect the severity of insulin resistance, whereas the surgical removal of adipose tissue may not evoke these changes."(New York Scott Gottlieb)