The multidirectional assessment of moderate caloric restriction and metformin treatment in obese patients.

Obesity treatment is often burdensome for patients. We used the combination of moderate caloric restriction (CR) with hypoglycemic metformin to assess their multidirectional effect in obese patients. One group was treated only with moderate CR (n=21) the second was treated with moderate CR and 800 mg metformin twice daily (n=23). Serum was drawn before and after treatment. The following parameters were monitored: anthropometric, cardiovascular, inflammatory, metabolic, and markers characteristic for thyroid, liver, pancreas, and kidney functions. Both tested groups did not significantly differ in most tested parameters after the treatment. Two groups reduced anthropometric parameters (body mass, body mass index (BMI), waist circumference) and fat mass but also muscle and fat-free mass, improving systolic blood pressure, insulin and leptin concentration, insulin sensitivity, leptin to adiponectin ratio, and inflammatory markers. Unfortunately, there was little impact on improving dyslipidemia and the thyroid and liver parameters. Free triiodothyronine (fT3) and gamma glutamyl transferase (GGT) activity were decreased in both groups, but triglycerides were reduced only in patients treated with moderate CR. Metformin with CR treatment decreases uric acid and aspartate aminotransferase (AspAT) activity. Metformin treatment with moderate CR in obese patients mainly improved insulin sensitivity, resulting in a reduction of patients with glucose intolerance, improved anthropometric, cardiovascular, and inflammatory mediators, and only slightly enhanced liver and thyroid function. No changes in kidney and pancreas function were observed during the treatment. In conclusion, eight weeks of CR alone and CR with metformin in obese adults improved anthropometric and metabolic markers, reduced muscle mass, fT3, GGT, proinflammatory, and CV parameters, and displayed no changes in kidney and pancreas function. The group treated with metformin after the treatment was still more obese and had higher C-reactive protein (CRP) and homeostasis model assessment-an index of insulin resistance (HOMA-IR), but despite this, considerably reduced the number of patients with glucose intolerance.

Soluble receptor for advanced glycation end products (sRAGE) correlates with obesity-related parameters, and it is not easy to be modified by moderate caloric restriction in obese humans.

Deficiency of a soluble form of the advanced glycation end products receptor (sRAGE) is implicated in obesity-induced complications. Serum sRAGE is inclined to be modified by changes in body weight. We analysed serum sRAGE concentrations in patients with obesity undergoing moderate calorie restriction, which mimics the real-life situation and is not harmful to obese humans. Serum sRAGE was measured by immunoassay in 50 patients with obesity who underwent calorie restriction by 300-500 kcal/day for 8 weeks. In effect calorie restriction resulted in an expected decrease in body weight (by 2.1 kg for an 8-week intervention, p<0.0001), as well as reduced systolic blood pressure, modified dyslipidemia (cholesterol, triglycerides), reduced obesity-related inflammation (tumor necrosis factor-alfa, interleukin-6, C-reactive protein), improved insulin sensitivity. However, it was not accompanied by any significant change in sRAGE concentration. There was a strong negative correlation between BMI and the sRAGE level. Accordingly, the levels of sRAGE were the highest in lean control. In conclusion: a modest weight reduction is unlikely to improve decreased sRAGE levels.

Weight loss-dependent and -independent effects of moderate calorie restriction on endothelial cell markers in obesity.

Endothelial cell dysfunction in obesity can be reduced by calorie restriction (CR), however it is unclear whether this benefit requires a concomitant weight loss or is it simply related to the reduced calorie intake per se. In our study serum was drawn from 41 obese women who were undergoing an 8-week dietary intervention with 15 - 30% energy deficit, and from 48 age- and sex-matched controls of normal weight. Serum was analysed for biomarkers of endothelial cell function, oxidative stress and inflammation. Compared with non-obese individuals, the obese patients had lower serum levels of nitric oxide (NO), adiponectin, and decreased serum antioxidant status. They also had significantly higher levels of adhesive molecules, thrombomodulin (TM), von Wilebrand factor (vWF), asymmetric dimethylarginine (ADMA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and leptin. To further characterize the effect of moderate CR, the patients were ranked into two comparable groups according to the extent of weight loss - below and above the median (-5.8 kg). A moderate dietary intervention did not correct adiponectin, antioxidant status, vWF, TM, and plasminogen activator inhibitor-1 (PAI-1) but ameliorated changes in other parameters. Only changes in NO and - to a lesser degree - in sE-selectin showed a clear relationship with the magnitude of weight reduction. By contrast, a beneficial reduction in TNF-α occurred equally in patients who lost more or less weight after caloric restriction. We concluded that moderate calorie restriction could still improve several parameters of endothelial cell function irrespective of whether it was accompanied by changes in body mass. However, a significant improvement in nitric oxide, a key mediator of endothelial well-being, requires a substantial reduction in body weight.