World Kidney Day Overweight can damage your kidneys

Kidneys can be burdened by obesity

03/11/2014

People who are severely overweight and have a body mass index of over 40 are more likely to have impaired kidney function than normal weight. So far, however, the exact mechanisms of kidney damage in obesity are unclear.

People with obesity have more often impaired kidney function
People who are severely overweight and have a body mass index of over 40 often have reduced kidney function compared to normal weight. The head of nephrology at the University Hospital Leipzig, Professor Tom Linder explained according to press reports: „In some patients, being overweight can have a negative effect on kidney function. This happens independently of other diseases such as hypertension or diabetes mellitus type 2, for which the risk is also greatly increased in overweight people. The first signs of kidney impairment may be increased levels of creatinine in the blood and excretion of urinary protein.“ The kidneys could therefore be adversely affected by obesity even if there are no complications of obesity.

Secondary diseases increase the kidney burden
However, the sequelae of Adipostas occur frequently and increase the kidney burden. Those affected initially suffer from a metabolic syndrome, which is a combination of symptoms such as sugar and lipid metabolism disorders and high blood pressure. Already the metabolic syndrome has a negative influence on the kidneys and untreated it often leads to the typical episodes of obesity such as cardiovascular diseases and diabetes mellitus type 2, which continue to add to the kidneys.

Effect only on a part of the patients
The Integrated Research and Treatment Center (IFB) Adiposity Diseases of the University of Leipzig and the Leipzig University Hospital also reports on new discoveries in obesity research on the occasion of World Kidney Day on 13 March. The scientists said that the exact mechanisms behind kidney damage in obesity are still unclear. It is interesting, however, that overweight only has a negative effect on kidney function in some patients.

Progranulin promotes inflammatory processes
One cause of the negative effect of adiposity on the kidneys could be that obese people increasingly have certain protein hormones from the adipose tissue (adipokines) in the blood. Leptin, for example, increases the sclerosis of blood vessels and this leads to a deterioration of kidney performance. The research of Thomas Ebert at IFB focuses on adipokine progranulin: „The levels of progranulin in the blood of patients with obesity or diabetes mellitus type 2 are significantly increased.“ Progranulin and its breakdown products promote inflammatory processes and can therefore increase the long-term risk of diabetes mellitus type 2 and arteriosclerosis.

Metabolism and kidneys impaired
Ebert was the first to demonstrate that a decreased kidney filtration rate is associated with elevated progranulin levels. Due to the reduced kidney function, these excess adipokines are not sufficiently excreted and further affect metabolism and kidneys. In the long term, this vicious circle could contribute to the increased rate of cardiovascular disease in renal impairment. In further research projects, it should be investigated whether the excess adipokines have a direct kidney-damaging effect. (Sb)