Académie royale de Médecine de Belgique

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Résumé de Luc Van Gaal (Séance du 20 mars 2010)

 

METABOLIC SYNDROME – FROM CONTROVERSIES TO ECTOPIC FAT SYNDROME

par  L. VAN GAAL (University Hospital – Antwerpen), invité.  

Metabolic syndrome -a cluster of less conventional risk factors for type 2 diabetes and cardiovascular disease- is known to be associated with abdominal obesity (adiposity), blood lipid disorders, inflammation, insulin resistance or glucose intolerance/type 2 diabetes and increased risk of developing cardiovascular disease.  Both abdominal adiposity as well as insulin resistance are very prevalent among metabolic syndrome patients.

Proposed criteria (ATP-III or IDF) for identifying patients with metabolic syndrome have contributed greatly to preventive medicine, but the value of metabolic syndrome as a scientific concept remains controversial.  Reasons for these controversial aspects are linked to different criteria used and different criteria for fat distribution across ethnicities.

In this controversy also the pathophysiology is of great importance: abdominal adiposity, insulin resistance and /or inflammation are potential key players in the mechanisms behind clustering of new risk factors.

Which risk factors can be considered as additional components of the syndrome also remains controversial: are coagulation factors, endothelial dysfunction, positive micro-albuminuria and inflammation part of it ?  These additional components relate to an excess release of adipocytokines from visceral adipose tissues, low levels of adiponectin with concomitant increase of TNFα and IL-6.

Accumulation of fat in other tissues (liver, muscle and heart-) refers to ectopic fat, contributing to insulin resistance, inflammation, lipid disturbances and subsequent endothelial dysfunction.

The presence of metabolic syndrome alone cannot predict global cardiovascular disease risk.  But abdominal obesity -the most prevalent manifestation of metabolic syndrome- is a marker of ‘dysfunctional adipose tissue’ and is of central importance in clinical diagnosis.  Better risk assessment algorithms are needed to quantify diabetes and cardiovascular disease risk on a global scale.  Recent data indicate that the metabolic syndrome better predicts type 2 diabetes than it is predictive for cardiovascular diseases.

Lifestyle intervention is by far the treatment option for the MS. Some pharmacological drugs may add some benefits, but always as add-on or to lifestyle intervention.

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