Lipometabolic disorders

Clinical information

As an endocrine organ, the fatty tissue secretes a variety of hormones called adipokines. In severely overweight individuals the adipocyte function is deregulated, resulting in alterations in adipokine production. Adiponectin and leptin are the most frequent adipokines. They represent a link between metabolic disorders and obesity through signal transduction.

The adiponectin expression is down-regulated in the fatty tissue obese individuals, resulting in lower levels as compared to normal-weight individuals. Adiponectin is insulin-sensitising, anti-inflammatory and protects from atherosclerosis.  The proinflammatory hormone leptin suppresses appetite and increases energy expenditure and weight loss. The leptin concentration in blood correlates with the mass of fatty tissue.

The greater the proportion of fatty tissue in the body, the more leptin is produced and passes through the blood-brain barrier into the satiety centre of the brain. In the case of leptin resistance, the satiety centres no longer respond to the hormone. Leptin resistance is one of the most common causes of overweight and obesity. Low adiponectin and increased leptin levels in obesity cause a weak chronic-grade inflammatory state, which promotes the development of insulin resistance and type 2 diabetes, high blood pressure, atherosclerosis and other cardiovascular diseases.

Diagnostics

Determination of the adipokine concentration can be helpful in the diagnosis and therapy of lipid metabolism disorders. The literature recommends determining the ratio of leptin and adiponectin in particular, rather than just the concentration of one of the hormones. EUROIMMUN therefore offers ELISA test systems for quantitative determination of the two parameters.