Overweight people get sick - others are not

Overweight people get sick - others are not

07/06/2014

Overweight and obesity are associated with many diseases. But not all fat people get sick. Researchers have now discovered that the HO-1 enzyme could be responsible for obese people suffering from common sequelae such as diabetes.

Healthy despite overweight
People who are overweight or obese have a higher risk of secondary or concomitant diseases such as diabetes, high blood pressure, lipid metabolism disorders, coronary heart disease such as heart attacks and certain cancers. Three out of four people develop such sequelae. Although the risk of becoming ill through obesity is significantly increased, there are people who remain healthy despite a strong overweight. Scientists from Germany, Austria and the United States have now found out what this is all about: a molecule is therefore responsible for the health and illness of the seriously overweight.

New target for diagnostic and therapeutic approaches
The researchers report in the journal „Cell“ "the influence of the molecule heme oxygenase (HO-1), which was previously thought to be involved in keeping vessels healthy or suppressing inflammation". Apparently, it also has a harmful effect. "People with low HO-1 activity rarely develop complications, and those with high levels of HO-1 have diabetes more often". „This strongly suggests that HO-1 acts directly at the interface between obesity and complications“, Harald Esterbauer is quoted by the University of Vienna, one of the study leaders, in a communication. Thus, the enzyme is a new target for diagnostic and therapeutic approaches. It could possibly help as a biomarker to better assess the disease risk of overweight people.

Overwhelming connection established
The researchers extracted tissue for examination from 51 individuals who had undergone weight-loss surgery. The patients had a body mass index (BMI) of more than 30 and were thus classified as obese. Six normal-weight people who underwent another surgical procedure served as a control group. „The relationship between HO-1 levels and patient health was overwhelming“, so Esterbauer. „Neither weight, fat nor the amount of unhealthy abdominal fat were more meaningful.“

Despite being overweight neither diabetes nor fatty liver
Investigations on mice provided insights into the metabolic connections. HO-1 therefore promotes chronic inflammation. Thus, although animals in which the enzyme in the phagocytes of the immune system, the macrophages, was genetically switched off, increased to like normal mice with intact enzyme. However, despite overweight, they did not develop diabetes or fatty liver, but remained healthy and lived as long as normal-weight conspecifics. The reason for this is that the loss of HO-1 defuses the macrophages. The phagocytes can no longer accumulate in the adipose tissue and thus cause chronic inflammation and type 2 diabetes. HO-1 also promotes diabetes directly, as further studies on mouse liver cells showed: Accordingly, cells without HO-1 responded better to insulin and can thus better absorb blood sugar. According to the scientists, the enzyme changes the insulin receptors of the cells and thus inhibits the effect of insulin.

Still years away from therapy
If the researchers are now looking for a drug that blocks the diabetes-promoting HO-1, a therapy based on the new findings may still be around ten years away. Just recently, a US study has been published that showed that 2.1 billion people worldwide overstated last year. According to researchers from Marie Ng of the University of Washington's Institute for Health Metrics and Evaluation (IHME), the proportion of thicknesses in both developed and developing countries has increased. In Germany, according to the Robert Koch Institute (RKI), the majority of men (67.1 percent) and women (53.0 percent) are overweight. With 23.3 percent in men and 23.9 percent in women, just under a quarter of adults are obese. According to the RKI, around six million people in this country suffer from diabetes type 1 or type 2. (ad)