Effectiveness of a low-calorie weight loss program in moderately and severely obese patients.

AIMS: To compare effectiveness of a 1-year weight loss program in moderately and severely obese patients. METHODS: The study sample included 311 obese patients participating in a weight loss program, which comprised a 12-week weight reduction phase (low-calorie formula diet) and a 40-week weight maintenance phase. Body weight and glucose and lipid values were determined at the beginning of the program as well as after the weight reduction and the weight maintenance phase. Participants were analyzed according to their BMI class at baseline (30-34.9 kg/m²; 35-39.9 kg/m²; 40-44.9 kg/m²; 45-49.9 kg/m²; ≥50 kg/m²). Furthermore, moderately obese patients (BMI < 40 kg/m²) were compared to severely obese participants (BMI ≥ 40 kg/m²). RESULTS: Out of 311 participants, 217 individuals completed the program. Their mean baseline BMI was 41.8 ± 0.5 kg/m². Average weight loss was 17.9 ± 0.6%, resulting in a BMI of 34.3 ± 0.4 kg/m² after 1 year (p < 0.001). Overall weight loss was not significantly different in moderately and severely obese participants. Yet, severely obese participants achieved greater weight loss during the weight maintenance phase than moderately obese participants (-3.1 ± 0.7% vs. -1.2 ± 0.6%; p = 0.04). Improvements in lipid profiles and glucose metabolism were found throughout all BMI classes. CONCLUSION: 1-year weight loss intervention improves body weight as well as lipid and glucose metabolism not only in moderately, but also in severely obese individuals.

Transcriptional regulation of adipocyte formation by the liver receptor homologue 1 (Lrh1)-Small hetero-dimerization partner (Shp) network.

Altered adipose tissue formation is a well-known effectors of obesity and T2D. Here, we describe the role of Lrh1 and its co-repressor Shp in the control of adipocyte formation. Expression of Lrh1 in the pre-adipocyte containing SVF is induced in obese mice models and humans while Shp expression is reduced. We demonstrate, that Lrh1 is an inhibitor of adipogenesis while Shp acts functions as an activator through repression of Lrh1 activity. This regulation is at least in part modulated by estradiol conversion through the regulation of Cyp19a1 gene expression. In vivo, loss of Lrh1 leads to induced adipogenesis, while loss of Shp causes uncontrolled activation of Lrh1 and reduced adipogenesis. As Shp expression has been linked to the development of obesity and metabolic disorders, it is possible that alterations of the Shp/Lrh1 network lead to changes in adipocyte formation, which might contribute to the development of obesity associated T2D.

Genetic modulation of the serotonergic pathway: influence on weight reduction and weight maintenance.

The serotonergic pathway plays a major role in the development of obesity. Its activity can be modulated by the 5-HT transporter-linked polymorphic region in the SLC6A4 gene and the upstream variable number of tandem repeats polymorphism in the MAOA gene. We studied whether these genetic modulations have an influence on weight reduction and weight maintenance in a one-year weight reduction program (OPTIFAST®52). The polymorphisms were genotyped by PCR in a sample of 135 female and 67 male subjects with severe obesity (44 ± 13 years, 122.3 ± 22.2 kg, BMI: 41.7 ± 6.7 kg/m2). The program leads to a total weight loss of 19.9 ± 9.8 kg (16.9 ± 8.3 %) in women and 27.4 ± 13.6 kg (20.4 ± 9.9 %) in men. Anthropometric measurements and blood levels were determined at the start of the program (T0), after the weight reduction phase (T1) and after the subsequent weight maintenance phase at the end of the program (T2). Each polymorphism alone did not significantly influence weight loss or weight maintenance neither in men nor in women. However, women carrying both risk genotypes (SS and 3/3) displayed a lower total weight loss during the program (p = 0.05). This effect derived mainly from difficulties in the weight maintenance phase (p = 0.11), while the weight reduction phase was not affected (p = 0.61). No influence was found in men (p = 0.93). Modulation of the serotonergic pathway by carrying both risk alleles seems to influence success of weight loss programs in women with severe obesity due to problems in stabilizing body weight after weight reduction.

TaqIA polymorphism in dopamine D2 receptor gene complicates weight maintenance in younger obese patients.

OBJECTIVE: The A1 allele of the TaqIA polymorphism in the dopamine D2 receptor gene (rs1800497) has been associated with obesity. However, the effect of the polymorphism on the success in weight loss and/or weight maintenance during weight-loss programs has not been evaluated thus far. METHODS: The rs1800497 was genotyped in 202 (135 female, 67 male) severely obese individuals with an initial body mass index of 41.7 ± 0.5 kg/m² who participated in a weight-loss program consisting of a weight-loss phase with a formula diet (12 wk) and a weight-maintenance phase (40 wk). Measurements were collected at baseline, after the weight-loss phase, and at the end of the weight-maintenance phase at 1 y. RESULTS: Genotyping revealed 4 A1A1, 67 A1A2, and 131 A2A2 genotype carriers. Of the 202 subjects in the program, 66.8% completed the program and 33.2% terminated prematurely. Neither the attrition rate (P = 0.44) nor the overall weight loss was influenced by the different genotypes (P = 0.96). However, younger A1⁺ participants (A1A1 and A1A2) had a higher body mass index at all time points (baseline, P = 0.04; after weight loss, P = 0.05; after weight maintenance, P = 0.02). They also showed less overall weight loss (P = 0.05), which derived mainly from a greater weight regain during the maintenance phase (P = 0.02). CONCLUSION: In this program, younger A1⁺ participants exhibited problems in maintaining weight loss during a weight-loss program.

Adipogenesis and insulin sensitivity in obesity are regulated by retinoid-related orphan receptor gamma.

Obesity is a well-known risk factor for the development of secondary complications such as type 2 diabetes. However, only a part of the obese population develops secondary metabolic disorders. Here, we identify the transcription factor retinoid-related orphan receptor gamma (RORγ) as a negative regulator of adipocyte differentiation through expression of its newly identified target gene matrix metalloproteinase 3. In vivo differentiation of adipocyte progenitor cells from Rorγ-deficient mice is enhanced and obese Rorγ(-/-) mice show decreased adipocyte sizes. These small adipocytes are highly insulin sensitive, leading to an improved control of circulating free fatty acids. Ultimately, Rorγ(-/-) mice are protected from hyperglycemia and insulin resistance in the state of obesity. In adipose stromal-vascular fraction from obese human subjects, Rorγ expression is correlated with adipocyte size and negatively correlated with adipogenesis and insulin sensitivity. Taken together, our findings identify RORγ as a factor, which controls adipogenesis as well as adipocyte size and modulates insulin sensitivity in obesity. RORγ might therefore serve as a novel pharmaceutical target to treat obesity-associated insulin resistance.