Metabolic syndrome, circulating RBP4, testosterone, and SHBG predict weight regain at 6 months after weight loss in men

An optimal growth pattern during pregnancy and early childhood associates with better fertility in men

OBJECTIVE

This study aimed to evaluate the association between birth weight (BW), childhood and adolescent BMI, with reproductive capacity in men.

DESIGN

A prospective, population-based cohort study (Northern Finland birth cohort 1966).

METHODS

Around 6196 men born in 1966 were followed from birth to age 50 years. Weight and height were measured repeatedly by professionals. Reproductive capacity (infertility assessment, male factor infertility and infertility treatment by age 46 years) was evaluated by questionnaires at ages 31 and 46 years. The number of children by the age of 50 years was recovered from registers. After excluding the men who reported never having attempted to have children or not answering the question at age 31 or 46 years (n = 2041), 4128 men were included in the final study population. Results were adjusted for BW, BW for gestational age (GA), mother's smoking status, marital status, educational level and smoking status.

RESULTS

Being small for GA (10.5% vs 8.2%, P = 0.012) or having a lower BW (3495 g vs 3548 g, P = 0.003) were associated with childlessness. The association was however no longer significant after adjusting for marital status. Being underweight in early childhood was associated with an increased risk of infertility assessment (adjusted, aOR: 2.04(1.07-3.81)) and childlessness (aOR: 1.47(1.01-2.17)) compared to the normal weight group. Conversely, overweight or obesity in early childhood was associated with a decreased risk of infertility assessment (aOR: 0.60 (0.41-0.87)), treatment (aOR: 0.42 (0.25-0.70)) and male factor infertility (aOR: 0.45 (0.21-0.97)). BMI in mid-childhood or puberty had no association with infertility or childlessness.

CONCLUSION

In boys, an optimal growth trajectory during pregnancy and early childhood seems to be very important for life-long fertility.

Plasma Levels of Triglycerides and IL-6 Are Associated With Weight Regain and Fat Mass Expansion

CONTEXT

Long-term weight loss (WL) maintenance is the biggest challenge for overweight and obesity because of the almost unavoidable phenomenon of partial or even total weight regain (WR) after WL.

OBJECTIVE

In the present study we investigated the relations of (the changes of) adipocyte size and other risk biomarkers with WR during the follow-up of the Yoyo dietary intervention.

METHODS

In this randomized controlled study, 48 overweight/obese participants underwent a very-low-calorie diet to lose weight, followed by a weight-stable period of 4 weeks and a follow-up period of 9 months. Anthropometric measurements, adipocyte volume of abdominal subcutaneous adipose tissue, and plasma metabolic parameters (free fatty acids [FFAs], triglycerides [TGs], total cholesterol, glucose, insulin, homeostasis model assessment of insulin resistance [HOMA-IR], interleukin 6 [IL-6], angiotensin-converting enzyme [ACE] activity, retinol binding protein 4 [RBP4]) at the beginning and the end of follow-up were analyzed.

RESULTS

Our results show that changes of TGs, IL-6, HOMA-IR, and ACE are significantly positively correlated with WR. Multiple linear regression analysis shows that only TG and IL-6 changes remained significantly correlated with WR and increased body fat mass. Moreover, the change in HOMA-IR was tightly correlated with the change in TGs. Surprisingly, change in adipocyte volume during follow-up was not correlated with WR nor with other factors, but positive correlations between adipocyte volume and HOMA-IR were found at the beginning and end of the follow-up.

CONCLUSION

These results suggest that TGs and IL-6 are independently linked to WR via separate mechanisms, and that HOMA-IR and adipocyte volume may indirectly link to WR through the change of plasma TGs.

Body mass cycling and predictors of body mass regain and its impact on cardiometabolic health

Caloric restriction (CR) is the first line intervention to reduce adiposity and total body mass (BM) to improve insulin resistance and ameliorate metabolic derangements. However, the lost adipose mass is difficult to maintain reduced in the long term due to several factors including compensatory changes in orexigenic hormones, adipokine release, pro-inflammatory state, adipose tissue morphology, and resting metabolic rate as a consequence of the caloric deficit. Hence, most patients undergoing a BM reduction intervention ultimately regain the lost mass and too often additional adipose mass overtime, which is hypothesized to have increased deleterious effects chronically. In this mini-review we describe the effects of BM cycling (loss and regain) on insulin resistance and cardiometabolic health and factors that may predict BM regain in clinical studies. We also describe the factors that contribute to the chronic deleterious effects of BM cycling in rodent models of diet-induced obesity (DIO) and other metabolic defects. We conclude that most of the improvements in insulin resistance are observed after a profound loss in BM regardless of the diet and that BM cycling abrogates these beneficial effects. We also suggest that more BM cycling studies are needed in rodent models resembling the development of type 2 diabetes mellitus (T2DM) in humans.

Weight regain after bariatric surgery: Promoters and potential predictors

Obesity is globally viewed as chronic relapsing disease. Bariatric surgery offers the most efficient and durable weight loss approach. However, weight regain after surgery is a distressing issue as obesity can revert. Surgical procedures were originally designed to reduce food intake and catalyze weight loss, provided that its role is marginalized in long-term weight maintenance. Consequently, it is essential to establish a scientifically standardized applicable definitions for weight regain, which necessitates enhanced comprehension of the clinical situation, as well as have realistic expectations concerning weight loss. Moreover, several factors are proposed to influence weight regain as psychological, behavioral factors, hormonal, metabolic, anatomical lapses, as well as genetic predisposition. Recently, there is a growing evidence of utilization of scoring system to anticipate excess body weight loss, along with characterizing certain biomarkers that identify subjects at risk of suboptimal weight loss after surgery. Furthermore, personalized counseling is warranted to help select bariatric procedure, reinforce self-monitoring skills, motivate patient, encourage mindful eating practices, to avoid recidivism.

Dietary weight loss-induced changes in RBP4, FFA, and ACE predict weight regain in people with overweight and obesity

Adipokines and other biomarkers were previously identified with roles in energy expenditure, appetite, satiety, and adiposity. Therefore, we investigated whether dietary weight loss‐induced changes in adipokines and other biomarkers known to play a role in weight regulation or energy expenditure could predict weight regain in people with overweight and obesity. In this randomized controlled trial 26 males and 30 females (BMI: 28–35 kg/m²) followed either a low‐calorie diet (LCD; 1250 kcal/day) for 12 weeks or a very‐low‐calorie diet (VLCD; 500 kcal/day) for 5 weeks followed by a weight stable period of 4 weeks (dietary intervention (DI) period) and a 9‐month follow‐up period. Blood samples were taken before and after each period to measure FFA, TAG, total cholesterol, insulin, glucose, angiotensin‐converting enzyme (ACE) activity, IL‐6, RBP4, apelin, leptin, adiponectin, vaspin, and nesfatin‐1 concentrations. Weight loss was similar between groups (LCD: −8.2 ± 0.5 kg; VLCD: −8.9 ± 0.4 kg, P = 0.30). Only changes in ACE activity, FFA and RBP4 concentrations during DI were correlated with weight regain in the whole group (r = −0.299, P = 0.030, r = −0.274, P = 0.047, and r = 0.357, P = 0.008, respectively). Together they explained 28% (r = 0.532) of weight regain variation. Dietary weight loss‐induced changes in ACE activity, FFA and RBP4 independently contribute to weight regain prediction.

Insulin sensitivity and its relation to hormones in adolescent boys and girls

BACKGROUND AND AIMS

A subset of obese individuals lacks cardiometabolic impairment. We aimed to analyze hormonal profiles of insulin-sensitive obese (ISO) and insulin-resistant obese (IRO) adolescents and determine hormonal predictors of homeostasis model of insulin resistance (HOMA-IR).

MATERIALS AND METHODS

A threshold of 3.16 of HOMA-IR was used to classify ISO (<3.16) IRO (≥3.16). In 702 individuals aged 13-18years (55.8% girls) anthropometric and laboratory [blood glucose, insulin, thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), sex hormone-binding globulin (SHBG), steroid hormones, luteinizing hormone, follicle stimulating hormone, prolactin, ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like-peptide 1glucagon, leptin, resistin, visfatin, leptin, adiponectin and adipsin] assessments were performed. Orthogonal projections to latent structures and Mann-Whitney tests with Bonferroni correction were applied for statistical analysis.

RESULTS

52.6% girls and 42.9% boys were insulin sensitive. In the predictive model of HOMA-IR thyroid function tests, adiponectin, ghrelin and leptin concentrations played an important role in both genders. Prolactin, testosterone and glucagon contributed to the model only in boys, while progesterone and dehydroepiandrosterone sulfate levels only in girls. After Bonferroni correction levels of leptin, adiponectin, leptin/adiponectin ratio, SHBG and fT4/TSH ratio in both genders, testosterone and glucagon levels in boys and levels of TSH and fT3 in girls were related to insulin sensitivity.

CONCLUSION

Metabolic health defined by HOMA-IR is partly predicted by various hormones. Some of them are gender specific. Free T4/TSH and leptin/adiponectin ratios are related to insulin sensitivity in both genders.

Weight loss-induced cellular stress in subcutaneous adipose tissue and the risk for weight regain in overweight and obese adults

BACKGROUND/OBJECTIVE

Weight loss is often followed by weight regain after the dietary intervention (DI). Cellular stress is increased in adipose tissue of obese individuals. However, the relation between cellular stress and weight regain is unclear. Previously, we observed increased adipose tissue cellular stress of participants regaining weight compared with participants maintaining weight loss. In the current study, we further investigated the relation between weight regain and changes in the expression of stress-related genes and stress protein levels to determine possible predictors of weight regain.

PARTICIPANTS/METHODS

In this randomized controlled trial, sixty-one healthy overweight/obese participants followed a DI of either a 5-week very-low-calorie diet (500 kcal per day) or a 12-week low-calorie diet (1250 kcal per day; WL period) with a subsequent 4-week weight stable diet (WS period), and a 9-month follow-up. The WL and WS period taken together was named the DI. Abdominal subcutaneous adipose tissue biopsies were collected in 53 participants for microarray and liquid chromatography-mass spectrometry analysis. RNA and protein levels for a broad set of stress-related genes were correlated to the weight regain percentage.

RESULTS

Different gene sets correlated to weight regain percentage during WS and DI. Bioinformatics clustering suggests that during the WS phase-defined genes for actin filament dynamics, glucose handling and nutrient sensing are related to weight regain. HIF-1 (hypoxia-inducible factor-1) is indicated as an important regulator. With regard to DI, clustering of correlated genes indicate that LGALS1, ENO1 and ATF2 are important nodes for conferring risk for weight regain.

CONCLUSIONS

Our present findings indicate that the risk for weight regain is related to expression changes of distinct sets of stress-related genes during the first 4 weeks after returning to energy balance, and during the DI. Further research is required to investigate the mechanistic significance of these findings and find targets for preventing weight regain.

Weight loss-induced stress in subcutaneous adipose tissue is related to weight regain

Initial successful weight loss is often followed by weight regain after the dietary intervention. Compared with lean people, cellular stress in adipose tissue is increased in obese subjects. However, the relation between cellular stress and the risk for weight regain after weight loss is unclear. Therefore, we determined the expression levels of stress proteins during weight loss and weight maintenance in relation to weight regain. In vivo findings were compared with results from in vitro cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. In total, eighteen healthy subjects underwent an 8-week diet programme with a 10-month follow-up. Participants were categorised as weight maintainers or weight regainers (WR) depending on their weight changes during the intervention. Abdominal subcutaneous adipose tissue biopsies were obtained before and after the diet and after the follow-up. In vitro differentiated SGBS adipocytes were starved for 96 h with low (0·55 mm) glucose. Levels of stress proteins were determined by Western blotting. WR showed increased expressions of β-actin, calnexin, heat shock protein (HSP) 27, HSP60 and HSP70. Changes of β-actin, HSP27 and HSP70 are linked to HSP60, a proposed key factor in weight regain after weight loss. SGBS adipocytes showed increased levels of β-actin and HSP60 after 96 h of glucose restriction. The increased level of cellular stress proteins in the adipose tissue of WR probably resides in the adipocytes as shown by in vitro experiments. Cellular stress accumulated in adipose tissue during weight loss may be a risk factor for weight regain.

Obesity and sex interact in the regulation of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, for which a number of genetic, environmental, and lifestyle risk factors have been identified. A significant modifiable risk factor is obesity in mid-life. Interestingly, both obesity and AD exhibit sex differences and are regulated by sex steroid hormones. Accumulating evidence suggests interactions between obesity and sex in regulation of AD risk, although the pathways underlying this relationship are unclear. Inflammation and the E4 allele of apolipoprotein E have been identified as independent risk factors for AD and both interact with obesity and sex steroid hormones. We review the individual and cooperative effects of obesity and sex on development of AD and examine the potential contributions of apolipoprotein E, inflammation, and their interactions to this relationship.

Weight regaining: From statistics and behaviors to physiology and metabolism

Achieving maintenance of weight loss is crucial to combat obesity. However, most individuals tend to regain weight. Data from successful maintainers show that they remain vigilant and constantly apply techniques to oppose the course of regaining. On the other hand, current advances in obesity research show that the reduced obese state is a state of altered physiology in terms of energy balance. This review describes the physiological adaptations occurring after weight loss that predispose to regaining. Specifically, changes regarding body composition, hormonal background, energy expenditure and control of food intake are discussed. Moreover, metabolites that can act as regain predictors and dietary techniques to oppose regaining are presented.

Testosterone and obesity

Testosterone is a key hormone in the pathology of metabolic diseases such as obesity. Low testosterone levels are associated with increased fat mass (particularly central adiposity) and reduced lean mass in males. These morphological features are linked to metabolic dysfunction, and testosterone deficiency is associated with energy imbalance, impaired glucose control, reduced insulin sensitivity and dyslipidaemia. A bidirectional relationship between testosterone and obesity underpins this association indicated by the hypogonadal-obesity cycle and evidence weight loss can lead to increased testosterone levels. Androgenic effects on enzymatic pathways of fatty acid metabolism, glucose control and energy utilization are apparent and often tissue specific with differential effects noted in different regional fat depots, muscle and liver to potentially explain the mechanisms of testosterone action. Testosterone replacement therapy demonstrates beneficial effects on measures of obesity that are partially explained by both direct metabolic actions on adipose and muscle and also potentially by increasing motivation, vigour and energy allowing obese individuals to engage in more active lifestyles. The degree of these beneficial effects may be dependent on the treatment modality with longer term administration often achieving greater improvements. Testosterone replacement may therefore potentially be an effective adjunctive treatment for weight management in obese men with concomitant hypogonadism.

Deep body composition phenotyping during weight cycling: relevance to metabolic efficiency and metabolic risk

Weight cycling may lead to adverse effects on metabolic efficiency (i.e. adaptive thermogenesis or 'metabolic slowing') and metabolic risks (e.g. increased risk for insulin resistance and the metabolic syndrome). In order to investigate these topics, the partitioning of fat and lean mass (i.e. the change in the proportion of both compartments) needs to be extended to the organ and tissue level because metabolic risk differs between adipose tissue depots and lean mass is metabolically heterogeneous being composed of organs and tissues differing in metabolic rate. Contrary to data obtained with severe weight loss and regain in lean people, weight cycling most likely has no adverse effects on fat distribution and metabolic risk in obese patients. There is even evidence for an increased ability of fat storage in subcutaneous fat depots (at the trunk in men and at the limbs in women) with weight cycling that may provide a certain protection from ectopic lipid deposition and thus explain the preservation of a favourable metabolic profile despite weight regain. On the other hand, the mass-specific metabolic rate of lean mass may increase with weight gain and decrease with weight loss mainly because of an increase and respective decrease in the proportion (and/or activity) of metabolically active organ mass. Obese people could therefore have a higher slope of the regression line between resting energy expenditure (REE) and fat-free mass that leads to an overestimation of metabolic efficiency when applied to normalize REE data after weight loss. Furthermore, in addressing the impact of macronutrient composition of the diet on partitioning of lean and fat mass, and the old controversy about whether a calorie is a calorie, we discuss recent evidence in support of a low glycaemic weight maintenance diet in countering weight regain and challenge this concept for weight loss by proposing the opposite.

From leptin to other adipokines in health and disease: facts and expectations at the beginning of the 21st century

This year marks the 20th anniversary of the discovery of leptin, which has tremendously stimulated translational obesity research. The discovery of leptin has led to realizations that have established adipose tissue as an endocrine organ, secreting bioactive molecules including hormones now termed adipokines. Through adipokines, the adipose tissue influences the regulation of several important physiological functions including but not limited to appetite, satiety, energy expenditure, activity, insulin sensitivity and secretion, glucose and lipid metabolism, fat distribution, endothelial function, hemostasis, blood pressure, neuroendocrine regulation, and function of the immune system. Adipokines have a great potential for clinical use as potential therapeutics for obesity, obesity related metabolic, cardiovascular and other diseases. After 20 years of intense research efforts, recombinant leptin and the leptin analog metreleptin are already available for the treatment of congenital leptin deficiency and lipodystrophy. Other adipokines are also emerging as promising candidates for urgently needed novel pharmacological treatment strategies not only in obesity but also other disease states associated with and influenced by adipose tissue size and activity. In addition, prediction of reduced type 2 diabetes risk by high circulating adiponectin concentrations suggests that adipokines have the potential to be used as biomarkers for individual treatment success and disease progression, to monitor clinical responses and to identify non-responders to anti-obesity interventions. With the growing number of adipokines there is an increasing need to define their function, molecular targets and translational potential for the treatment of obesity and other diseases. In this review we present research data on adipose tissue secreted hormones, the discovery of which followed the discovery of leptin 20 years ago pointing to future research directions to unravel mechanisms of action for adipokines.

The role of higher protein diets in weight control and obesity-related comorbidities

The importance of the relative dietary content of protein, carbohydrate and the type of carbohydrate (that is, glycemic index (GI)) for weight control under ad libitum conditions has been controversial owing to the lack of large scale studies with high diet adherence. The Diet, Obesity and Genes (DioGenes) European multicentre trial examined the importance of a slight increase in dietary protein content, reduction in carbohydrate and the importance of choosing low (LGI) vs high GI (HGI) carbohydrates for weight control in 932 obese families. Only the adults underwent a diet of 800 kcal per day for 8 weeks, and after losing ~11kg they were randomized to one of five energy ad libitum diets for 6 months. The diets differed in protein content and GI. The high-protein (HP) diet groups consumed 5.4% points more energy from protein than the normal protein (NP) groups, and the LGI diet groups achieved 5.1% lower GI than the HGI groups. The effect of HP and LGI was additive on weight loss and maintenance, and the combination was successful in preventing weight regain and reducing drop-out rate among the adults after the 11kg weight loss. This diet also reduced body fatness and prevalence of overweight and obesity among their children and had consistent beneficial effects on blood pressure, blood lipids and inflammation in both parents and children. After 1 year, mainly the HP effects were maintained. Putative genes have been identified that suggest this diet to be particularly effective in 67% of the population. In conclusion, the DioGenes diet has shown to be effective for prevention of weight regain and for weight reduction in overweight children under ad libitum conditions. The less-restrictive dietary approach fits into a normal food culture, and has been translated into popular diet and cook books in several languages.

Testosterone and weight loss: the evidence

PURPOSE OF REVIEW

The purpose of this article is to examine the contemporary data linking testosterone therapy in overweight and obese men with testosterone deficiency to increased lean body mass, decreased fat mass, improvement in overall body composition and sustained weight loss. This is of paramount importance because testosterone therapy in obese men with testosterone deficiency represents a novel and a timely therapeutic strategy for managing obesity in men with testosterone deficiency.

RECENT FINDINGS

Long-term testosterone therapy in men with testosterone deficiency produces significant and sustained weight loss, marked reduction in waist circumference and BMI and improvement in body composition. Further, testosterone therapy ameliorates components of the metabolic syndrome. The aforementioned improvements are attributed to improved mitochondrial function, increased energy utilization, increased motivation and vigor resulting in improved cardio-metabolic function and enhanced physical activity.

SUMMARY

The implication of testosterone therapy in management of obesity in men with testosterone deficiency is of paramount clinical significance, as it produces sustained weight loss without recidivism. On the contrary, alternative therapeutic approaches other than bariatric surgery failed to produce significant and sustained outcome and exhibit a high rate of recidivism. These findings represent strong foundations for testosterone therapy in obese men with testosterone deficiency and should spur clinical research for better understanding of usefulness of testosterone therapy in treatment of underlying pathophysiological conditions of obesity.

Crosstalk between circulating peroxisome proliferator-activated receptor gamma, adipokines and metabolic syndrome in obese subjects

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPARγ) has direct and indirect function in adipokines production process. We aimed to assess the possible influence of circulating PPARγ on relative risk of metabolic syndrome and also examine the association between circulating PPARγ and adipokines levels among obese subjects.

METHODS

A total of 96 obese subjects (body mass index (BMI) ≥30) were included in the current cross-sectional study. We assessed the body composition with the use of Body Composition Analyzer BC-418MA - Tanita. The MetS (metabolic syndrome) was defined based on the National Cholesterol Education Program Adult Treatment Panel III. All baseline blood samples were obtained following an overnight fasting. Serum concentrations of adipokines including Retinol binding protein 4 (RBP4), omentin-1, vaspin, progranulin, nesfatin-1 and circulating PPARγ was measured with the use of an enzyme-linked immunosorbent assay method. Statistical analyses were performed using software package used for statistical analysis (SPSS).

RESULTS

We found main association between circulating PPARγ and body composition in obese population. The risk of metabolic syndrome in subjects with higher concentration of PPARγ was 1.9 fold in compared with lower concentration of PPARγ after adjustment for age, sex and BMI. There was significant association between PPARγ and adipokines, specially nesfatin-1 and progranulin. Defined adipokines pattern among participants demonstrated the markedly higher concentration of vaspin, RBP4 and nesfatin-1 in participants with MetS compared to non-MetS subjects.

CONCLUSIONS

It appears all of studied adipokines might have association with PPARγ level and might simultaneously be involve in some common pathway to make susceptible obese subjects for MetS.