Serum uric acid potentially links metabolic health to measures of fuel use in lean and obese individuals.

BACKGROUND AND AIMS: Uric acid (UA) is a byproduct of the high-energy purine metabolism and is conventionally regarded as a marker of cardio-metabolic impairment. Its potential relationship with energy homeostasis is unknown to date. METHODS AND RESULTS: In a cross-sectional study on 121 otherwise healthy obese and 99 sex- and-age-matched lean subjects, UA levels were analyzed in relation to metabolic health, inflammatory markers, respiratory quotient (RQ) and resting energy expenditure (REE) as assessed by indirect calorimetry, fat mass (%FM) and fat-free mass (FFM) as determined by bioimpedance analysis. As expected, obese and lean subjects differed in BMI, glucolipid homeostasis, leptin and insulin levels, inflammatory markers, %FM and FFM (p < 0.001 for all). Likewise, UA levels (p < 0.001) and rates of hyperuricaemia (40.5% vs 3.0%, p < 0.0001) were also higher in obese than lean controls. Further, indirect calorimetry confirmed that obesity increased REE and decreased RQ significantly (p < 0.001). Beyond the expected metabolic correlates, in individual and merged groups UA levels were associated negatively with RQ and positively with REE (p < 0.0001 for both). In multivariable regression analysis, significant independent predictors of UA were BMI and sex. When BMI was replaced by measures of body composition, %FM and FFM emerged as significant predictors of serum UA (p < 0.0001). CONCLUSIONS: A potential link relates serum UA to measures of resting energy expenditure and their determinants.

Effect of chronic treatment with beta-blockers on resting energy expenditure in obese hypertensive patients during a low-calorie and physical training program.

BACKGROUND AND AIM: To evaluate whether chronic treatment with beta-blockers influences resting energy expenditure (REE) and weight loss after a period of diet and physical activity in obese hypertensive patients. METHODS AND RESULTS: Seventy-eight obese hypertensive patients (24 males and 54 females) aged 53.7 +/- 11.1 years with mean BMI of 42.4 +/- 5.8 kg/m2 were enrolled. Thirty-eight patients were using beta-blockers while 40 patients who had not received beta-blockers in the past 6 months were the control group. REE was measured with indirect calorimetric method. Total body fat mass, total body fat-free mass (FFM) and total body water (W) were determined by bioelectrical impedance analysis. Patients and controls underwent a structured physical training program and a hypocaloric diet for a period of 31.6 +/- 10.6 days. Measured REE in patients taking beta-blockers was 1818 +/- 309 kcal/24 h and 1853 +/- 348 kcal/24 h in patients not taking beta-blockers; p = non significant. Weight and BMI loss were similar between the two groups and were respectively -6.43 +/- 2.62 kg and -2.42 +/- 0.91 kg/m2 in the beta-blocker group and -7.49 +/- 3.10 kg, -2.78 +/- 1.03 kg/m2 in the non beta-blocker group. Body composition was similar in the two groups. In the comparison between patients treated with selective beta 1-adrenoceptors blockers and non selective beta-blockers we found a significant difference in REE (1704 +/- 283 vs 1974 +/- 278; p = 0.012) and in weight loss (-5.6 +/- 2.4 vs -7.5 +/- 2.7; p = 0.048) at the end of study. CONCLUSIONS: Beta-blockers are not associated with a lower REE in obese subjects compared to other antihypertensive treatment. Use of non selective beta-adrenergic blockers is associated with a higher REE and weight loss compared to use of selective beta 1-adrenergic blockers. Non selective beta-blockers could be indicated among first choice drugs in hypertensive severely obese subjects without contraindications to beta-blockade.

Feasibility of air plethysmography (BOD POD) in morbid obesity: a pilot study.

The assessment of body composition (BC) in morbidly obese patients is a difficult procedure. Air-displacement plethysmography (ADP), which measures body density, is a very promising technique for BC assessment in health and disease. However, there are very few data about the feasibility of applying ADP on morbidly obese patients, which theoretically could be affected by large body size and difficulty in lung volume measurements. The main aim of this pilot study was to evaluate the feasibility of using ADP for BC assessment in morbidly obese patients. We studied nine subjects (6 males and 3 females) who had a mean age (+/-SD) of 47.0+/-13.5 years and body mass index (BMI) of 46.6+/-7.7 kg/m(2) (range 36.4-58.8). All patients could fit into the instrument chamber and perform the manoeuvre for pulmonary plethysmography. Mean lung volume was 3.9+/-1.2 l and mean percent body fat was 53.1+/-6.6 (range 46.0-67.5). These results indicate that ADP appears to be suitable for patients with BMI over 40 kg/m(2) and produces realistic BC data.