Healthy obese persons: how can they be identified and do metabolic profiles stratify risk?

Atherosclerosis as the Damocles' sword of human evolution: insights from nonhuman ape-like primates, ancient human remains, and isolated modern human populations

Atherosclerosis is the leading cause of death worldwide, and the predominant risk factors are advanced age and high-circulating low-density lipoprotein cholesterol (LDL-C). However, the findings of atherosclerosis in relatively young mummified remains and a lack of atherosclerosis in chimpanzees despite high LDL-C call into question the role of traditional cardiovascular risk factors. The inflammatory theory of atherosclerosis may explain the discrepancies between traditional risk factors and observed phenomena in current literature. Following the divergence from chimpanzees several millennia ago, loss of function mutations in immune regulatory genes and changes in gene expression have resulted in an overactive human immune system. The ubiquity of atherosclerosis in the modern era may reflect a selective pressure that enhanced the innate immune response at the cost of atherogenesis and other chronic disease states. Evidence provided from the fields of genetics, evolutionary biology, and paleoanthropology demonstrates a sort of circular dependency between inflammation, immune system functioning, and evolution at both a species and cellular level. More recently, the role of proinflammatory stimuli, somatic mutations, and the gene-environment effect appear to be underappreciated elements in the development and progression of atherosclerosis. Neurobiological stress, metabolic syndrome, and traditional cardiovascular risk factors may instead function as intermediary links between inflammation and atherosclerosis. Therefore, considering evolution as a mechanistic process and atherosclerosis as part of the inertia of evolution, greater insight into future preventative and therapeutic interventions for atherosclerosis can be gained by examining the past.

Diabetes Mellitus and Its Risk Factors among Migrant Workers in Kuwait

The prevalence of diabetes mellitus (DM) is growing enormously worldwide, and actions need to be taken in order to minimize the burden of diabetes mellitus and reduce its complications. Since two-thirds of Kuwait's population are expatriates, the prevalence of and factors associated with diabetes among migrant workers was assessed as it has a significant impact on migrant workers' quality of life, health, and productivity. The data used in this study was for all migrant workers who attended Shuaiba Industrial Medical Center (SIMC) for physical examination in the year 2018. Univariate and multivariate regression were used to assess the relationship between diabetes mellitus and the other independent factors where odds ratios with confidence intervals were delineated. Information for a total of 3477 participants was recorded in the dataset for 2018. Of the total participants, 10.1% had diabetes mellitus. About 49% of the participants were overweight. The largest age group of participants was between 31 and 40 years of age. A small percentage of the participants were diagnosed with hypertension at 11.8%. Additionally, 76.1% of the participants reported themselves as non-smokers. Diabetes was positively associated with age, hypertension, and nationalities. However, no association was found between BMI and smoking tobacco. This is the first study in SIMC to assess DM and its associated risk factor among migrants, since migrant workers are neglected subpopulations that need our focus and attention to achieve justice and fairness. The findings revealed that the prevalence of DM among our study population was considerably lower. However, a healthy lifestyle, including a healthy diet and being physically active, need to be introduced to prevent any further damage.

Adipocyte Biology from the Perspective of In Vivo Research: Review of Key Transcription Factors

Obesity and type 2 diabetes are both significant contributors to the contemporary pandemic of non-communicable diseases. Both disorders are interconnected and associated with the disruption of normal homeostasis in adipose tissue. Consequently, exploring adipose tissue differentiation and homeostasis is important for the treatment and prevention of metabolic disorders. The aim of this work is to review the consecutive steps in the postnatal development of adipocytes, with a special emphasis on in vivo studies. We gave particular attention to well-known transcription factors that had been thoroughly described in vitro, and showed that the in vivo research of adipogenic differentiation can lead to surprising findings.

Neuronal Lipoprotein Lipase Deficiency Alters Neuronal Function and Hepatic Metabolism

The autonomic regulation of hepatic metabolism offers a novel target for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the molecular characteristics of neurons that regulate the brain-liver axis remain unclear. Since mice lacking neuronal lipoprotein lipase (LPL) develop perturbations in neuronal lipid-sensing and systemic energy balance, we reasoned that LPL might be a component of pre-autonomic neurons involved in the regulation of hepatic metabolism. Here, we show that, despite obesity, mice with reduced neuronal LPL (NEXCreLPL^flox (LPL KD)) show improved glucose tolerance and reduced hepatic lipid accumulation with aging compared to wilt type (WT) controls (LPL^flox). To determine the effect of LPL deficiency on neuronal physiology, liver-related neurons were identified in the paraventricular nucleus (PVN) of the hypothalamus using the transsynaptic retrograde tracer PRV-152. Patch-clamp studies revealed reduced inhibitory post-synaptic currents in liver-related neurons of LPL KD mice. Fluorescence lifetime imaging microscopy (FLIM) was used to visualize metabolic changes in LPL-depleted neurons. Quantification of free vs. bound nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) revealed increased glucose utilization and TCA cycle flux in LPL-depleted neurons compared to controls. Global metabolomics from hypothalamic cell lines either deficient in or over-expressing LPL recapitulated these findings. Our data suggest that LPL is a novel feature of liver-related preautonomic neurons in the PVN. Moreover, LPL loss is sufficient to cause changes in neuronal substrate utilization and function, which may precede changes in hepatic metabolism.

Strong association between metabolically-abnormal obesity and gallstone disease in adults under 50 years

Background

Age, obesity, and metabolic syndrome are known risk factors for gallstones; however, the combined impact of these different risk factors on gallstone formation has not yet been examined.

Methods

This retrospective, cross-sectional study involved 3190 participants, including 207 participants (6.5%) with gallstones and 986 (30.9%) with metabolic syndrome. Participants were divided into four phenotypes according to metabolic syndrome and obesity status: 1378 participants were metabolically healthy and non-obese (MHNO); 826 were metabolically healthy but obese (MHO); 185 were metabolically abnormal but not obese (MANO); and 801 participants were metabolically abnormal and obese (MAO).

Results

The MAO and MANO phenotypes had more gallstones than the MHO and MHNO phenotypes, regardless of age (< 50 or ≥ 50 years old). Multivariate analyses showed that phenotype was an independent risk factor for gallstones in participants < 50 years old (odds ratio (OR) = 1.73, 95% confidence interval (CI) = 1.32–2.28). Younger participants also had a higher risk of gallstones in the MAO (OR = 5.41, 95% CI = 2.31–12.66), MANO (OR = 3.18, 95% CI = 0.86–11.75), and MHO (OR = 2.17, 95% CI = 0.90–5.22) phenotypes than the MHNO phenotype.

Conclusions

Our retrospective results demonstrate an increased association of gallstones in younger people (< 50 years old) with metabolic syndrome and obesity.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-1032-y) contains supplementary material, which is available to authorized users.

Тhe prevalence of metabolically healthy obesity: data from the epidemiological survey in of Novosibirsk

Background: Obesity is associated with numerous metabolic complications, such as type 2 diabetes mellitus (DM2), dyslipidemia, arterial hypertension (AH), cardiovascular diseases and some forms of cancer. Nevertheless, the literature describes a group of obese individuals who are more resistant to the development of metabolic disorders. At present, this phenomenon is known as "Metabolically healthy obesity", "metabolically healthy obesity" (MZO). Despite the presence of excess weight or obesity, a favorable metabolic profile can be observed in this cohort of patients, characterized by preserved insulin sensitivity, absence of arterial hypertension, normal lipid, hormonal profile, absence of inflammation and unchanged hepatic transaminases. Aims: To study the prevalence of metabolically healthy obesity (MHO) and its characteristics in men and women at the age of 4569 years in Novosibirsk. Materials and methods: To study covered 3197 persons from the base of the international project HAPPIE. They had a body mass index (BMI 30 kg/m). Metabolically healthy obesity was determined as obesity (BMI 30 kg/m, with 2 and fewer components of metabolic syndrome (MS) by criteria NCEP ATP III, 2001. Statistical analisys SPSS-13. Results: The prevalence of metabolic healthy obesity (MHO) was 42% (38% for men and 43% for women). The examined people with MHO have reliably more favorable average level of TG, HDL-cholesterol, indicators of blood glucose, systolic arterial pressure and diastolic arterial pressure and less waist circumference. In the groups withMHO and MS abdominal obesity is common in men at 95 and 71%, in women at 99 and 90%; hyperTG in men at 74 and 9%, in women at 72 and 5,5%; lower level HDL-cholesterol in 16 and 1% for men, and in 44,5% and 3% for women; AP in 96 and 77% and 94 and 71% in men and women respectively, the frequency fasting of hyperglycaemia 77 and 21% in men and 60 and 5% in women was markedly different. According to the data obtained by us, the frequency in the sample is high and amounted to 42%. In the subgroup the most commonly found is the MHO phenotype 53%, than in the men -38%, р 0,001 Conclusions: According to our data, the frequency of metabolic healthy obesity in the sample is high and amounted to 42%. In the female subgroup, a metabolically healthy phenotype is more common 43% than in the male 38%, p 0.001. Metabolically healthy obese individuals are characterized by a significantly lower incidence of fasting hyperglycaemia and dyslipidemia.

Body size phenotypes comprehensively assess cardiometabolic risk and refine the association between obesity and gut microbiota

OBJECTIVE

The gut microbiota associates with obesity and related disorders, but recent meta-analyses have found that this association is, at best, of small effect. We argue that such analyses are flawed by the use of body mass index (BMI) as sole proxy for disease, and explore a classification method that distinguishes the cardiometabolic health status of individuals to look for more comprehensive associations between gut microbes and health.

DESIGN

We analyzed a 441 community-dwelling cohort on which we obtained demographic and health information, anthropometry and blood biochemistry data that served to categorize participants according to BMI, cardiometabolic health status and body size phenotypes. In addition, the participants donated fecal samples from which we performed 16S rRNA gene sequencing to analyze the gut microbiota.

RESULTS

We observed that health-related variables deteriorate with increased BMI, and that there are further discrepancies within a given BMI category when distinguishing cardiometabolically healthy and unhealthy individuals. Regarding the gut microbiota, both obesity and cardiovascular disease associate with reductions in α-diversity; having lean, healthy individuals the most diverse microbiotas. Moreover, the association between the gut microbiota and health stems from particular consortia of microbes; the prevalence of consortia involving pathobionts and Lachnospiraceae are increased in obese and cardiometabolically abnormal subjects, whereas consortia including Akkermansia muciniphila and Methanobrevibacter, Oscillospira and Dialister have higher prevalence in cardiometabolically healthy and normoweight participants.

CONCLUSIONS

The incorporation of cardiometabolic data allows a refined identification of dissimilarities in the gut microbiota; within a given BMI category, marker taxa associated with obesity and cardiometabolic disease are exacerbated in individuals with abnormal health status. Our results highlight the importance of the detailed assessment and classification of individuals that should be carried out prior to the evaluation of obesity treatments targeting the gut microbiota.

Catalase overexpression modulates metabolic parameters in a new 'stress-less' leptin-deficient mouse model

Oxidative stress plays a key role in obesity by modifying the function of important biological molecules, thus altering obesogenic pathways such as glucose and lipid signaling. Catalase, is an important endogenous antioxidant enzyme that catabolizes hydrogen peroxide produced by the dismutation of superoxide. Recent studies have shown knockdown of catalase exacerbates insulin resistance and leads to obesity. We hypothesized that overexpressing catalase in an obese mouse will modulate obesogenic pathways and protect against obesity. Therefore, we bred catalase transgenic ([Tg(CAT)^+/-] mice with Ob/Ob mice to generate the hybrid "Bob-Cat" mice. This newly generated "stress-less" mouse model had decreased oxidative stress (oxidized carbonylated proteins). ECHO-MRI showed lower fat mass but higher lean mass in "Bob-Cat" mice. Comprehensive Lab Animal Monitoring System (CLAMS) showed light and dark cycle increase in energy expenditure in Bob-Cat mice compared to wild type controls. Circulating levels of leptin and resistin showed no change. Catalase mRNA expression was increased in key metabolic tissues (adipose, liver, intestinal mucosa, and brain) of the Bob-Cat mice. Catalase activity, mRNA and protein expression was increased in adipose tissue. Expression of the major adipokines leptin and adiponectin was increased while pro-inflammatory genes, MCP-1/JE and IL-1β were lowered. Interestingly, sexual dimorphism was seen in body composition, energy expenditure, and metabolic parameters in the Bob-Cat mice. Overall, the characteristics of the newly generated "Bob-Cat" mice make it an ideal model for studying the effect of redox modulators (diet/exercise) in obesity.

Prevalence and clinical characteristics of metabolically healthy obese individuals and other obese/non-obese metabolic phenotypes in a working population: results from the Icaria study

BACKGROUND

Metabolically healthy obese (MHO) phenotype may present with distinct characteristics compared with those with a metabolically unhealthy obese phenotype. Epidemiologic data on the distribution of these conditions in the working population are lacking. We aimed to evaluate the prevalence and clinical characteristics of MHO and other obese/non-obese metabolic phenotypes in a working population.

METHODS

Cross-sectional analysis of all subjects who had undergone a medical examination with Ibermutuamur Prevention Society from May 2004 to December 2007. Participants were classified into 5 categories according to their body mass index (BMI); within each of these categories, participants were further classified as metabolically healthy (MH) or metabolically unhealthy (MUH) according to the modified NCEP-ATPIII criteria. A logistic regression analysis was performed to evaluate some clinically relevant factors associated with a MH status.

RESULTS

In the overall population, the prevalence of the MHO phenotype was 8.6%. The proportions of MH individuals in the overweight and obese categories were: 87.1% (overweight) and 55.5% (obese I-III [58.8, 40.0, and 38.7% of the obese I, II, and III categories, respectively]). When the overweight and obese categories were considered, compared with individuals who were MUH, those who were MH tended to be younger and more likely to be female or participate in physical exercise; they were also less likely to smoke, or to be a heavy drinker. In the underweight and normal weight categories, compared with individuals who were MH, those who were MUH were more likely to be older, male, manual (blue collar) workers, smokers and heavy drinkers. Among participants in the MUH, normal weight group, the proportion of individuals with a sedentary lifestyle was higher relative to those in the MH, normal weight group. The factors more strongly associated with the MUH phenotype were BMI and age, followed by the presence of hypercholesterolemia, male sex, being a smoker, being a heavy drinker, and lack of physical exercise.

CONCLUSIONS

The prevalence of individuals with a MHO phenotype in the working population is high. This population may constitute an appropriate target group in whom to implement lifestyle modification initiatives to reduce the likelihood of transition to a MUH phenotype.

Development of a Weight Loss Mobile App Linked With an Accelerometer for Use in the Clinic: Usability, Acceptability, and Early Testing of its Impact on the Patient-Doctor Relationship

Background

Although complications of obesity are well acknowledged and managed by clinicians, management of obesity itself is often difficult, which leads to its underdiagnosis and undertreatment in hospital settings. However, tools that could improve the management of obesity, including self-monitoring, engagement with a social network, and open channels of communication between the patient and doctor, are limited in a clinic-based setting.

Objective

The objective of our study was to evaluate the usability and acceptability of a newly developed mobile app linked with an accelerometer and its early effects on patient-doctor relationships.

Methods

From September 2013 to February 2014, we developed a mobile app linked with an accelerometer as a supportive tool for a clinic-based weight loss program. The app used information from electronic health records and delivered tailored educational material. Personal goal setting, as well as monitoring of weight changes and physical activity combined with feedback, are key features of the app. We also incorporated an interactive message board for patients and doctors. During the period of March 2014 to May 2014, we tested our mobile app for 1 month in participants in a hospital clinic setting. We assessed the app’s usability and acceptability, as well as the patient-doctor relationship, via questionnaires and analysis of app usage data.

Results

We recruited 30 individuals (18 male and 12 female) for the study. The median number of log-ins per day was 1.21, with the most frequently requested item being setting goals, followed by track physical activities and view personal health status. Scales of the depth of the patient-doctor relationship decreased from 27.6 (SD 4.8) to 25.1 (SD 4.5) by a Wilcoxon signed rank test (P=.02).

Conclusions

A mobile phone app linked with an accelerometer for a clinic-based weight loss program is useful and acceptable for weight management but exhibited less favorable early effects on patient-doctor relationships.

Fibrinogen production is enhanced in an in-vitro model of non-alcoholic fatty liver disease: an isolated risk factor for cardiovascular events?

Background

Cardiovascular disease (CVD) remains the major cause of excess mortality in patients with non-alcoholic fatty liver disease (NAFLD). The aim of this study was to investigate the individual contribution of NAFLD to CVD risk factors in the absence of pathogenic influences from other comorbidities often found in NAFLD patients, by using an established in-vitro model of hepatic steatosis.

Methods

Histopathological events in non-alcoholic fatty liver disease were recapitulated by focused metabolic nutrient overload of hepatoblastoma C3A cells, using oleate-treated-cells and untreated controls for comparison. Microarray and proteomic data from cell culture experiments were integrated into a custom-built systems biology database and proteogenomics analysis performed. Candidate genes with significant dysregulation and concomitant changes in protein abundance were identified and STRING association and enrichment analysis performed to identify putative pathogenic pathways.

Results

The search strategy yielded 3 candidate genes that were specifically and significantly up-regulated in nutrient-overloaded cells compared to untreated controls: fibrinogen alpha chain (2.2 fold), fibrinogen beta chain (2.3 fold) and fibrinogen gamma chain (2.1 fold) (all rank products pfp <0.05). Fibrinogen alpha and gamma chain also demonstrated significant concomitant increases in protein abundance (3.8-fold and 2.0-fold, respectively, p <0.05).

Conclusions

In-vitro modelling of NAFLD and reactive oxygen species formation in nutrient overloaded C3A cells, in the absence of pathogenic influences from other comorbidities, suggests that NAFLD is an isolated determinant of CVD. Nutrient overload-induced up-regulation of all three fibrinogen component subunits of the coagulation cascade provides a possible mechanism to explain the excess CVD mortality observed in NAFLD patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0069-3) contains supplementary material, which is available to authorized users.

Neuroimaging and neuromodulation approaches to study eating behavior and prevent and treat eating disorders and obesity

Functional, molecular and genetic neuroimaging has highlighted the existence of brain anomalies and neural vulnerability factors related to obesity and eating disorders such as binge eating or anorexia nervosa. In particular, decreased basal metabolism in the prefrontal cortex and striatum as well as dopaminergic alterations have been described in obese subjects, in parallel with increased activation of reward brain areas in response to palatable food cues. Elevated reward region responsivity may trigger food craving and predict future weight gain. This opens the way to prevention studies using functional and molecular neuroimaging to perform early diagnostics and to phenotype subjects at risk by exploring different neurobehavioral dimensions of the food choices and motivation processes. In the first part of this review, advantages and limitations of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), pharmacogenetic fMRI and functional near-infrared spectroscopy (fNIRS) will be discussed in the context of recent work dealing with eating behavior, with a particular focus on obesity. In the second part of the review, non-invasive strategies to modulate food-related brain processes and functions will be presented. At the leading edge of non-invasive brain-based technologies is real-time fMRI (rtfMRI) neurofeedback, which is a powerful tool to better understand the complexity of human brain-behavior relationships. rtfMRI, alone or when combined with other techniques and tools such as EEG and cognitive therapy, could be used to alter neural plasticity and learned behavior to optimize and/or restore healthy cognition and eating behavior. Other promising non-invasive neuromodulation approaches being explored are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS). Converging evidence points at the value of these non-invasive neuromodulation strategies to study basic mechanisms underlying eating behavior and to treat its disorders. Both of these approaches will be compared in light of recent work in this field, while addressing technical and practical questions. The third part of this review will be dedicated to invasive neuromodulation strategies, such as vagus nerve stimulation (VNS) and deep brain stimulation (DBS). In combination with neuroimaging approaches, these techniques are promising experimental tools to unravel the intricate relationships between homeostatic and hedonic brain circuits. Their potential as additional therapeutic tools to combat pharmacorefractory morbid obesity or acute eating disorders will be discussed, in terms of technical challenges, applicability and ethics. In a general discussion, we will put the brain at the core of fundamental research, prevention and therapy in the context of obesity and eating disorders. First, we will discuss the possibility to identify new biological markers of brain functions. Second, we will highlight the potential of neuroimaging and neuromodulation in individualized medicine. Third, we will introduce the ethical questions that are concomitant to the emergence of new neuromodulation therapies.

Immune regulators of inflammation in obesity-associated type 2 diabetes and coronary artery disease

PURPOSE OF REVIEW

To summarize current work identifying inflammatory components that underlie associations between obesity-associated type 2 diabetes and coronary artery disease.

RECENT FINDINGS

Recent studies implicate immune cells as drivers of pathogenic inflammation in human type 2 diabetes. Inflammatory lymphocytes characterize unhealthy adipose tissue, but regional adipose volume, primarily visceral and pericardial fat, also predict severity and risk for obesity-associated coronary artery disease. Having a greater understanding of shared characteristics between inflammatory cells from different adipose tissue depots and a more accessible tissue, such as blood, will facilitate progress toward clinical translation of our appreciation of obesity as an inflammatory disease.

SUMMARY

Obesity predisposes inflammation and metabolic dysfunction through multiple mechanisms, but these mechanisms remain understudied in humans. Studies of obese patients have identified disproportionate impacts of specific T cell subsets in metabolic diseases like type 2 diabetes. On the basis of demonstration that adipose tissue inflammation is depot-specific, analysis of adiposity by waist-to-hip ratio or MRI will increase interpretive value of lymphocyte-focused studies and aid clinicians in determining which obese individuals are at highest risk for coronary artery disease. New tools to combat obesity-associated coronary artery disease and other comorbidities will stem from identification of immune cell-mediated inflammatory networks that are amenable to pharmacological interventions.

Markers of metabolic and cardiovascular health in adults: Comparative analysis of DEXA-based body composition components and BMI categories

OBJECTIVES

To investigate how body composition components fit body mass index (BMI) categories and whether they could be considered as markers of metabolic and cardiovascular health.

DESIGN

Prospective study.

SETTING

A center for preventive medicine.

PARTICIPANTS

Six hundred and sixteen consecutive outpatients: mean age of 56.0±10.0 years; 74.6% aged ≥50 years and 61.4% were females.

MEASUREMENTS

Fat mass (FM) and muscle mass (MM) were obtained by dual energy X-ray absorptiometry analyses. Metabolically unhealthy individuals were defined as people with biological features of dyslipidemia, hyperuricemia, diabetes, and/or hepatitis steatosis. Documented hypertension and/or atherosclerosis of one major artery, at least, defined individuals with cardiovascular complications.

RESULTS

According to BMI categories, 45.8% of the sample was of normal weight, while 19.2% and 16.5% were classified as overweight and obese. A total of 78.0% and 86.3% of overweight and obese individuals were metabolically unhealthy respectively, 46.8% and 52.6% of subjects classified into normal and underweight BMI categories were also diagnosed. Cardiovascular complications mainly concerned the two highest BMI groups (78.2%). In multifactorial analyses the overweight and obese BMI categories were predictive of health outcomes [respectively, odds ratio (OR)=8.05, 95% confidence interval (CI): 4.23-12.07 and 5.74, 95% CI: 3.41-8.98]. FM and MM indexes were significantly associated with metabolic (OR=1.30, 95% CI: 1.19-1.47; and 0.84, 95% CI: 0.78-0.91) and cardiovascular (OR=1.22, 95% CI: 1.13-1.32; and 0.72, 95% CI: 0.65-0.80) health respectively, and FM/MM (respectively, OR=15.45, 95% CI: 11.77-20.17; and 16.61, 95% CI: 10.49-21.33) as well.

CONCLUSION

Our findings suggest that FM and MM readouts are important measurements of nutritional status and they extend the analysis of its impact on health outcomes to all BMI categories. Moreover, they highlight the interest of measuring body composition in medical check-ups to predict metabolic and cardiovascular diseases.