The Effect of Bariatric Surgery on Insulin Sensitivity and Energy Metabolism (BARIA-DDZ)

  • End date
    Dec 28, 2023
  • participants needed
  • sponsor
    German Diabetes Center
Updated on 28 May 2022
insulin sensitivity
bariatric surgery
gastric banding
Accepts healthy volunteers


The purpose of this study is:

  1. To explore to what extent insulin sensitivity, energy metabolism and ectopic lipid storage can be improved by bariatric surgery
  2. To explore to what extent hepatic and muscular disorders of energy metabolism occur in patients with obesity (degree 2-3)
  3. To explore whether the steato liver occurring in patients with obesity (degree 2-3) is associated with the degree of liver inflammation


Insulin resistance strongly relates to ectopic lipid deposition in skeletal muscle and the liver, which correlate with insulin resistance. Lipid metabolites accumulating in skeletal muscle and the liver are thought to impair insulin signalling and thereby reduce glucose uptake and glycogen storage. Insulin resistant humans frequently present with decreased mitochondrial function in skeletal muscle which might contribute to lipid accumulation and the development of insulin resistance. Non-alcoholic liver disease (NAFLD) comprise fatty liver, steatohepatitis and cirrhosis. NAFLD correlate with insulin resistance increased risk for cardiovascular diseases, type 2 diabetes and hepatocellular. The mechanisms leading from fatty liver to steatohepatitis and insulin resistance in the liver are yet unclear. Bariatric surgery relates to surgery for the reduction of body weight. Bariatric surgery frequently leads to normalization of glucose tolerance in previously diabetic humans even before the onset of body weight reduction. The underlying mechanisms are yet unclear. In this study we aim to explore the mechanisms underlying the onset of insulin resistance and steatohepatitis in patients with fatty liver and to identify the mechanisms leading to improved glucose tolerance in humans after bariatric surgery. We test the following hypotheses: increased lipid availability leads to (i) increased lipid oxidation and oxidative stress (ii) accumulation of lipid metabolites that impair insulin signalling (iii) bariatric surgery improves insulin sensitivity by increasing lipid oxidation.

This study will contribute to the understanding of NAFLD and will help to identify new targets for the therapy of diabetes.

Condition Obesity, Diabetes Mellitus, Type 2
Treatment Surgery
Clinical Study IdentifierNCT01477957
SponsorGerman Diabetes Center
Last Modified on28 May 2022


Yes No Not Sure

Inclusion Criteria

Aged ≥ 20 years- ≤ 70 years
BMI 20- 25 kg/m 2 normal- weight group
BMI 35- 39,9 kg/m 2 (Obesity grade 2)
BMI >40 kg/m 2 (Obesity grade 3)

Exclusion Criteria

Autoimmune or Immune disorder diseases (Leukozyten < 5000/µl
Acute illness 2 weeks before start of examination
Renal insufficiency (Kreatin > 1,5 mg/dl)
Heart disease, condition after heart attack
Anemia (Hb <12g/l, controlled before every day of examination) or blood donations 4weeks before examination
Participation in another trial within the last 2 weeks
Pharmacological- immunotherapy (Cortisol, Antihistaminika, ASS)
Glitazone Therapy
Thyroid disorders
Pregnancy, Lactation, Menstruation
Smoking cigarettes, Alcohol- and drug abuse
Psychiatric disorders
Risk for/ or diagnosed HIV/ AIDS or Hepatitis B/C
Liver disease, which are not caused by non- alcoholic steato- hepatitis
Working on night shifts or irregular rhythm of night- day
Impaired wound healing or clotting disorders
Allergic reaction to local anesthetics
Malignant cancer
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