ABSTRACT
Accurate weight predictions are essential for weight management program patients. The freely available National Institutes of Health Body Weight Planner (NIH-BWP) returns expected weights over time but overestimates weight when patients consume a low-calorie diet. This study sought to increase the accuracy of NIH-BWP predicted weights for people on low-calorie diets. People enrolled in a weight management program were included if they received meal replacements with defined caloric content for the 3 months of the weight loss phase of the program. The Ottawa Weight Loss Prediction Model (OWL-PM) modelled the relative difference between observed and NIH-BWP predicted weights using longitudinal analysis methods based on patient factors. OWL-PM was externally validated. 1761 people were included (mean age 46 years, 73.3% women) with a mean (SD) baseline weight in pounds and body mass index of 271.9 (55.6) and 43.9 (7.4), respectively. At the end of the program's weight loss phase, people lost a median (IQR) of 17.1% (14.8-19.5) of their baseline weight. Observed weight relative to NIH-BWP predicted weights had a median value of - 4.9% but ranged from - 32.1% to + 28.5%. After adjustment, weight overestimation by NIH-BWP was most pronounced in male patients, people without diabetes and with increased observation time. OWL-PM returned expected weights at 3 months that were significantly more accurate than those from NIH-BWP alone (mean difference observed vs. expected [95% CI] 6.7lbs [6.4-7.0] vs. 12.6lbs [12.1-13.0]). In the external validation cohort (n = 106), OWL-PM was significantly more accurate than NIH-BWP (mean squared error 24.3 vs. 40.0, p = 0.0018). OWL-PM incorporated patient-level covariates to significantly increase weight prediction accuracy of NIH-BWP in patients consuming a low-calorie diet.
Subject(s)
Caloric Restriction , Weight Loss , Humans , Male , Female , Middle Aged , Caloric Restriction/methods , Adult , Body Mass Index , United States , Obesity/diet therapy , Diet, Reducing/methodsABSTRACT
ABSTRACT: The weapons of mass destruction-civil support team (WMD-CST) physician associate/assistant (PA) is an autonomous PA who balances military and civilian roles to achieve mission success and support the safety of the US public. This article by multiple WMD-CST PAs across the nation describes the WMD-CST PA profession and how traditional PA roles continue to advance.
Subject(s)
Military Personnel , Physicians , Humans , Weapons of Mass DestructionABSTRACT
Objective: Full meal replacement (FMR) Intensive Lifestyle Interventions (ILI) have been used for weight management. However, predictors of efficacy with these programs are less clear. The primary objective was to assess weight loss predictors in a community-based FMR ILI program. A secondary objective was to determine if weight loss was different between virtual and in person ILI. Methods: This was a retrospective cohort study involving 234 patients who started the program between 1 January 2016 and 3 March 2021. In the 24-week program, patients spent 12 weeks on FMR and then transitioned back to food for the remainder, with weekly follow up with a physician and group sessions with a dietitian. Visits were in person prior to March 2020 and virtual afterward. Results: Patients' average age was 47.5 years (SD = 12.0) and 73.5% were female. Average weight loss was 14.3% (SD = 6.2%). There was no significant difference in weight loss between virtual and in person programs. Patients on a Glucagon-like Peptide-1 Receptor Agonist prior lost less weight. Other significant associations between groups were baseline Hemoglobin A1C, classes attended, as well as the age since peak weight. Conclusion: Weight loss from virtual ILI was not significantly different from person ILI. More research is needed to determine how to best stratify care as virtual or in person using FMR programs.
ABSTRACT
Models predicting individual body weights over time clarify patient expectations in weight loss programs. The accuracy of two commonly used weight prediction models in community living people is unclear. All eligible people entering a weight management program between 1992 and 2015 were included. Patients' diet was 1200 kcal/day for week 0 followed by 900 kcal/day for weeks 1-7 and were excluded from the analysis if they were nonadherent. We generated expected weights using the National Institutes of Health Body Weight Planner (NIH-BWP) and the Pennington Biomedical Research Center Weight Loss Predictor (PBRC-WLP). 3703 adherent people were included (mean age 46 years, 72.6% women, mean [SD] weight 262.3 pounds [54.2], mean [SD] BMI 42.4 [7.6]). Mean (SD) relative body weight differences (100*[observed-expected]/expected) for NIH-BWP and PBRC-WLP models was - 1.5% (3.8) and - 2.9% (3.2), respectively. At week 7, mean squared error with NIH-BWP (98.8, 83%CI 89.7-108.8) was significantly lower than that with PBRC-WLP (117.7, 83%CI 112.4-123.4). Notable variation in relative weight difference were seen (for NIH-BWP, 5th-95th percentile was - 6.2%, + 3.7%; Δ 9.9%). During the first 7 weeks of a weight loss program, both weight prediction models returned expected weights that were very close to observed values with the NIH-BWP being more accurate. However, notable variability between expected and observed weights in individual patients were seen. Clinicians can monitor patients in weight loss programs by comparing their progress with these data.
Subject(s)
Weight Reduction Programs , Humans , Female , Middle Aged , Male , Weight LossABSTRACT
There is a significant threat to global health security due to synthetic opioids, illicitly manufactured fentanyl (IMF), and nefarious uses of pharmaceutical based agents (PBA). Since 2014, increased distribution of synthetic opioids including IMF into the US through China, India, and Mexico has resulted in devastating consequences to the average street drug user. Additionally, clandestine lab operations for pill manufacturing and distribution have increased, along with unintentional drug overdoses due to drugs being laced with fentanyl or some other synthetic opioid derivative. Naloxone has been shown to be an effective and useful tool for reversing signs and symptoms of synthetic opioid overdose, though additional doses may be required depending on the analog. In addition to the risk of overdose in US civilians, other state actors have utilized fentanyl and its analogs as incapacitants resulting in significant numbers of casualties. The National Guard Weapons of Mass Destruction-Civil Support Teams (WMD-CST) have been on the front lines supporting federal law enforcement agencies with hazard identification and assessment. Physician Assistants (PA) are assigned to these units and provide the necessary skills and expertise to keep on scene personnel safe. This article aims to dispel some of the rumors and myths surrounding fentanyl in an effort to educate first receivers, first responders, and hospital providers. Lastly, this article provides a review of synthetic opioid production, overdose, hazards, treatment/countermeasures, decontamination for responders, and the potential use of synthetic opioids as WMDs.
Subject(s)
Drug Overdose , Illicit Drugs , Humans , Analgesics, Opioid/therapeutic use , Fentanyl/therapeutic use , Naloxone/therapeutic use , Drug Overdose/drug therapyABSTRACT
BACKGROUND: Current paradigms for predicting weight loss in response to energy restriction have general validity but a subset of individuals fail to respond adequately despite documented diet adherence. Patients in the bottom 20% for rate of weight loss following a hypocaloric diet (diet-resistant) have been found to have less type I muscle fibres and lower skeletal muscle mitochondrial function, leading to the hypothesis that physical exercise may be an effective treatment when diet alone is inadequate. In this study, we aimed to assess the efficacy of exercise training on mitochondrial function in women with obesity with a documented history of minimal diet-induced weight loss. METHODS: From over 5000 patient records, 228 files were reviewed to identify baseline characteristics of weight loss response from women with obesity who were previously classified in the top or bottom 20% quintiles based on rate of weight loss in the first 6 weeks during which a 900 kcal/day meal replacement was consumed. A subset of 20 women with obesity were identified based on diet-resistance (n=10) and diet sensitivity (n=10) to undergo a 6-week supervised, progressive, combined aerobic and resistance exercise intervention. FINDINGS: Diet-sensitive women had lower baseline adiposity, higher fasting insulin and triglycerides, and a greater number of ATP-III criteria for metabolic syndrome. Conversely in diet-resistant women, the exercise intervention improved body composition, skeletal muscle mitochondrial content and metabolism, with minimal effects in diet-sensitive women. In-depth analyses of muscle metabolomes revealed distinct group- and intervention- differences, including lower serine-associated sphingolipid synthesis in diet-resistant women following exercise training. INTERPRETATION: Exercise preferentially enhances skeletal muscle metabolism and improves body composition in women with a history of minimal diet-induced weight loss. These clinical and metabolic mechanism insights move the field towards better personalised approaches for the treatment of distinct obesity phenotypes. FUNDING: Canadian Institutes of Health Research (CIHR-INMD and FDN-143278; CAN-163902; CIHR PJT-148634).
Subject(s)
Insulins , Obesity , Adenosine Triphosphate/metabolism , Canada , Diet, Reducing , Exercise/physiology , Female , Humans , Insulins/metabolism , Mitochondria/metabolism , Muscle, Skeletal/metabolism , Obesity/metabolism , Serine/metabolism , Sphingolipids/metabolism , Triglycerides/metabolism , Weight LossABSTRACT
Metabolic demands of skeletal muscle are substantial and are characterized normally as highly flexible and with a large dynamic range. Skeletal muscle composition (e.g., fiber type and mitochondrial content) and metabolism (e.g., capacity to switch between fatty acid and glucose substrates) are altered in obesity, with some changes proceeding and some following the development of the disease. Nonetheless, there are marked interindividual differences in skeletal muscle composition and metabolism in obesity, some of which have been associated with obesity risk and weight loss capacity. In this review, we discuss related molecular mechanisms and how current and novel treatment strategies may enhance weight loss capacity, particularly in diet-resistant obesity.
Subject(s)
Muscle, Skeletal , Obesity , Fatty Acids/metabolism , Humans , Mitochondria/metabolism , Mitochondria, Muscle/metabolism , Muscle, Skeletal/metabolism , Obesity/metabolism , Weight Loss/physiologyABSTRACT
OBJECTIVES: Our aim in this study was to compare the change in waist circumference given the same degree of weight loss in patients who meet the criteria for metabolic syndrome or type 2 diabetes and those who do not meet these criteria. Because visceral adiposity is a key feature of both conditions and intra-abdominal adipocytes show higher lipolytic activity, we sought to determine whether changes in waist circumference differed in individuals with and without these conditions. METHODS: The Ottawa Hospital Weight Management Clinic offers a course in lifestyle modification and uses 12 weeks of total meal replacement. We compared the decrease in waist circumference between patients with metabolic syndrome or diabetes and those without these conditions who had lost a similar amount of weight using measurements from the first 6 weeks of meal replacement. RESULTS: We evaluated 3,559 patients who attended the program between September 1992 and April 2015. The patient population was largely Caucasian and of European descent and all meetings were face to face. The mean weight loss for men was 15.1±20.2 kg, and the mean weight loss for women was 9.7±2.4 kg. There were no significant differences in decrease in waist circumference between those with and without metabolic syndrome in both men (11.7±3.9 cm vs 11.4±3.8 cm, p=0.48) and women (9.0±3.6 cm vs 9.1±3.7 cm, p=0.26). CONCLUSIONS: Our results show that, given the same degree of weight loss, patients with and without diabetes or metabolic syndrome experience a similar change in waist circumference.
Subject(s)
Diabetes Mellitus, Type 2 , Metabolic Syndrome , Body Mass Index , Diabetes Mellitus, Type 2/epidemiology , Female , Humans , Male , Metabolic Syndrome/epidemiology , Waist Circumference , Weight LossABSTRACT
PURPOSE: Roux-en-Y gastric bypass (RYGB) surgery produces significant weight loss. However, a number of patients experience weight regain years after surgery. Factors driving weight regain after surgical interventions are currently being explored. Our objective was to investigate appetite-related measures associated with weight regain after RYGB surgery. MATERIALS AND METHODS: Using a cross-sectional design, 29 participants (49.6 ± 9.1 years of age; current BMI 32.4 ± 4.7 kg/m2, 43.6 ± 8.9 months post-RYGB) were stratified into tertiles according to weight regain per month after nadir (weight maintenance (WM), n = 9; low weight regain (LWR), n = 10; and high weight regain (HWR), n = 10). The average weight regain was, by design, significantly different between the groups (WM = 2.2 ± 2.5 kg; LWR = 10.0 ± 3.4 kg; HWR = 14.9 ± 6.3 kg regained, p < 0.05). Appetite (visual analog scales), olfactory performance ("sniffin sticks"), eating behaviors (Three Factor Eating Questionnaire), food reward (Leeds Food Preference Questionnaire), and appetite-related hormones (ghrelin, PYY, GLP-1 and leptin) were measured fasting and in response to a standardized test meal. RESULTS: Dietary restraint was significantly higher than clinical cutoffs in WM and LWR (p < 0.05). As expected, significant time effects were noted for ghrelin, PYY, and GLP-1, but there were no group differences. CONCLUSION: The results suggest that appetite-related outcomes are similar across individuals who have maintained weight loss and experienced regain following RYGB.
Subject(s)
Gastric Bypass , Obesity, Morbid , Appetite/physiology , Body Weight Maintenance , Cross-Sectional Studies , Gastric Bypass/methods , Ghrelin , Glucagon-Like Peptide 1 , Humans , Obesity, Morbid/surgery , Weight Gain/physiology , Weight Loss/physiologyABSTRACT
Obesity derives from an extended period of positive energy imbalance due to a complex interplay of environmental and biological factors. Muscle fiber type and physiology have been hypothesized to affect metabolism and energy expenditure and thus to affect an individual's propensity to gain weight. However, there have been conflicting reports regarding a relationship between muscle fiber type and obesity. Here, we systematically reviewed literature investigating this topic from PubMed, Web of Science, and EMBASE. Of these, 32 articles were included in our final review and analysis. Most studies (22/32) reported a significant relationship between muscle fiber-type proportion and a measure of obesity. Overall, there was a significant negative relationship between the proportion of type I fibers and body mass index (BMI) and a significant positive relationship between the proportion of type IIX fibers and BMI. Moreover, between-group comparisons indicated a greater prevalence of type IIX fibers and a lower prevalence of type I fibers in patients living with obesity relative to lean individuals. These significant relationships were confirmed in a meta-analysis of these data. The causal nature of these associations remains to be evaluated.
Subject(s)
Muscle Fibers, Skeletal , Obesity , Body Mass Index , Humans , Muscle Fibers, Skeletal/metabolism , Obesity/complicationsABSTRACT
Here, we performed a genome-wide search for methylation sites that contribute to the risk of obesity. We integrated methylation quantitative trait locus (mQTL) data with BMI GWAS information through a SNP-based multiomics approach to identify genomic regions where mQTLs for a methylation site co-localize with obesity risk SNPs. We then tested whether the identified site contributed to BMI through Mendelian randomization. We identified multiple methylation sites causally contributing to the risk of obesity. We validated these findings through a replication stage. By integrating expression quantitative trait locus (eQTL) data, we noted that lower methylation at cg21178254 site upstream of CCNL1 contributes to obesity by increasing the expression of this gene. Higher methylation at cg02814054 increases the risk of obesity by lowering the expression of MAST3, whereas lower methylation at cg06028605 contributes to obesity by decreasing the expression of SLC5A11. Finally, we noted that rare variants within 2p23.3 impact obesity by making the cg01884057 site more susceptible to methylation, which consequently lowers the expression of POMC, ADCY3 and DNAJC27. In this study, we identify methylation sites associated with the risk of obesity and reveal the mechanism whereby a number of these sites exert their effects. This study provides a framework to perform an omics-wide association study for a phenotype and to understand the mechanism whereby a rare variant causes a disease.
Subject(s)
DNA Methylation/genetics , Epigenome/genetics , Genetic Predisposition to Disease/genetics , Obesity/genetics , Adenylyl Cyclases/genetics , Body Mass Index , Cyclins/genetics , Epigenomics/methods , Genome-Wide Association Study , HSP40 Heat-Shock Proteins/genetics , Humans , Mendelian Randomization Analysis , Microtubule-Associated Proteins/genetics , Phenotype , Polymorphism, Single Nucleotide/genetics , Pro-Opiomelanocortin/genetics , Protein Serine-Threonine Kinases/genetics , Quantitative Trait Loci , Risk Factors , Sodium-Glucose Transport Proteins/genetics , rab GTP-Binding Proteins/geneticsABSTRACT
Current obesity treatment strategies include diet, exercise, bariatric surgery, and a limited but growing repertoire of medications. Individual weight loss in response to each of these strategies is highly variable. Here we review research into factors potentially contributing to inter-individual variability in response to treatments for obesity, with a focus on studies in humans. Well-recognized factors associated with weight loss capacity include diet adherence, physical activity, sex, age, and specific medications. However, following control for each of these, differences in weight loss appear to persist in response to behavioral, pharmacological and surgical interventions. Adaptation to energy deficit involves complex feedback mechanisms, and inter-individual differences likely to arise from a host of poorly defined genetic factors, as well as differential responses in neurohormonal mechanisms (including gastrointestinal peptides), metabolic efficiency and capacity of tissues, non-exercise activity thermogenesis, thermogenic response to food, and in gut microbiome. A better understanding of the factors involved in inter-individual variability in response to therapies will guide more personalized approaches to the treatment of obesity.
Subject(s)
Obesity/physiopathology , Weight Loss , Bariatric Surgery , Energy Metabolism , Exercise , Humans , Obesity/metabolism , Obesity/surgery , ThermogenesisABSTRACT
Chronic inflammation is a common feature of obesity, with elevated cytokines such as interleukin-1 (IL-1) in the circulation and tissues. Here, we report an unconventional IL-1R-MyD88-IRAK2-PHB/OPA1 signaling axis that reprograms mitochondrial metabolism in adipocytes to exacerbate obesity. IL-1 induced recruitment of IRAK2 Myddosome to mitochondria outer membranes via recognition by TOM20, followed by TIMM50-guided translocation of IRAK2 into mitochondria inner membranes, to suppress oxidative phosphorylation and fatty acid oxidation, thereby attenuating energy expenditure. Adipocyte-specific MyD88 or IRAK2 deficiency reduced high-fat-diet-induced weight gain, increased energy expenditure and ameliorated insulin resistance, associated with a smaller adipocyte size and increased cristae formation. IRAK2 kinase inactivation also reduced high-fat diet-induced metabolic diseases. Mechanistically, IRAK2 suppressed respiratory super-complex formation via interaction with PHB1 and OPA1 upon stimulation of IL-1. Taken together, our results suggest that the IRAK2 Myddosome functions as a critical link between inflammation and metabolism, representing a novel therapeutic target for patients with obesity.
Subject(s)
Adipocytes/immunology , Inflammation/immunology , Interleukin-1 Receptor-Associated Kinases/metabolism , Interleukin-1/metabolism , Mitochondrial Membranes/metabolism , Obesity/immunology , Adipocytes/pathology , Animals , Cells, Cultured , Humans , Interleukin-1 Receptor-Associated Kinases/genetics , Male , Mice , Mice, Knockout , Myeloid Differentiation Factor 88/genetics , Myeloid Differentiation Factor 88/metabolism , Oxidative Phosphorylation , Prohibitins , Protein Transport , Receptors, Interleukin-1/metabolism , Signal TransductionABSTRACT
Weight loss in response to energy restriction is highly variable, and identification of genetic contributors can provide insights into underlying biology. Leveraging 1000 Genomes imputed genotypes, we carried out genome-wide association study (GWAS) analysis in 551 unrelated obese subjects of European ancestry who participated in an intensively supervised weight loss program with replication of promising signals in an independent sample of 1,331 obese subjects who completed the program at a later date. By single nucleotide polymorphism-based and sib-pair analysis, we show that that weight loss is a heritable trait, with estimated heritability (h 2 = 0.49) within the range reported for obesity. We find rs679482, intronic to SGCG (sarcoglycan γ), highly expressed in skeletal muscle, to concordantly associate with weight loss in discovery and replication samples reaching GWAS significance in the combined meta-analysis (ß = -0.35, P = 1.7 × 10-12). Located in a region of open chromatin, rs679482 is predicted to bind DMRT2, and allele-specific transcription factor binding analysis indicates preferential binding of DMRT2 to rs679482-A. Concordantly, rs679482-A impairs native repressor activity and increases basal and DMRT2-mediated enhancer activity. These findings confirm that weight loss is a heritable trait and provide evidence by which a novel variant in SGCG, rs679482, leads to impaired diet response.
Subject(s)
Obesity/therapy , Outpatients , Polymorphism, Single Nucleotide , Sarcoglycans/genetics , Weight Loss/genetics , Weight Reduction Programs , Adult , Female , Genetic Predisposition to Disease , Genotype , Humans , Introns , Male , Middle Aged , Obesity/genetics , White People/geneticsABSTRACT
Molecular quantitative trait locus (QTL) analyses are increasingly popular to explore the genetic architecture of complex traits, but existing studies do not leverage shared regulatory patterns and suffer from a large multiplicity burden, which hampers the detection of weak signals such as trans associations. Here, we present a fully multivariate proteomic QTL (pQTL) analysis performed with our recently proposed Bayesian method LOCUS on data from two clinical cohorts, with plasma protein levels quantified by mass-spectrometry and aptamer-based assays. Our two-stage study identifies 136 pQTL associations in the first cohort, of which >80% replicate in the second independent cohort and have significant enrichment with functional genomic elements and disease risk loci. Moreover, 78% of the pQTLs whose protein abundance was quantified by both proteomic techniques are confirmed across assays. Our thorough comparisons with standard univariate QTL mapping on (1) these data and (2) synthetic data emulating the real data show how LOCUS borrows strength across correlated protein levels and markers on a genome-wide scale to effectively increase statistical power. Notably, 15% of the pQTLs uncovered by LOCUS would be missed by the univariate approach, including several trans and pleiotropic hits with successful independent validation. Finally, the analysis of extensive clinical data from the two cohorts indicates that the genetically-driven proteins identified by LOCUS are enriched in associations with low-grade inflammation, insulin resistance and dyslipidemia and might therefore act as endophenotypes for metabolic diseases. While considerations on the clinical role of the pQTLs are beyond the scope of our work, these findings generate useful hypotheses to be explored in future research; all results are accessible online from our searchable database. Thanks to its efficient variational Bayes implementation, LOCUS can analyze jointly thousands of traits and millions of markers. Its applicability goes beyond pQTL studies, opening new perspectives for large-scale genome-wide association and QTL analyses. Diet, Obesity and Genes (DiOGenes) trial registration number: NCT00390637.
Subject(s)
Bayes Theorem , Blood Proteins/genetics , Quantitative Trait Loci , Biomarkers/blood , Genome-Wide Association Study , HumansABSTRACT
BACKGROUND: Obesity is increasing globally. Chronic kidney disease (CKD) is strongly associated with obesity. Kidney function is commonly estimated with equations using creatinine (such as CKD-EPI equation) which is a product of muscle metabolism. Decisions about categorizing CKD, planning modality of renal replacement therapies, and adjusting dosages of medications excreted by the kidneys are done using these equations. However, it is not well appreciated that creatinine-based equations may not accurately estimate kidney function in obese individuals. We plan a systematic review of diagnostic studies which will compare estimating equations to actual measured kidney function. METHODS: We will systematically search electronic bibliographic databases including MEDLINE, EMBASE, and the Cochrane Library with no restrictions on language or specific dates. The search terms will be adapted for the different databases using a combination of Medical Subject Heading and relevant keywords contained in titles and abstracts. Our preliminary search strategy using Cochrane, MEDLINE, and EMBASE databases have identified 190, 1246, and 1660 citations, respectively. For all studies selected, we will extract information on general study characteristics, study participant (age, sex, ethnicity, weight, height, BMI, BSA), type and protocol of reference standard utilized, the index test studied, the methodology of measurement of index test, categories of GFR, the proportion of eGFR within 10, 20, 30, 40, and 50% of measured GFR, and bias between eGFR and measured GFR. If the quality of methods and risk of bias are adequate, we will perform a meta-analysis. We will assess the heterogeneity using the χ 2 and the I 2 statistics to examine whether the estimates from studies included could be pooled. Sensitivity and multivariate meta-regression analyses will be performed to assess the effects of clinical factors and socio-demographic characteristics reported in included studies on the meta-analytic estimates. All analysis will be performed using the Comprehensive Meta-analysis software. DISCUSSION: This systematic review might help to inform clinicians on the best equation to use in patients with obesity and CKD for staging of CKD and for medication dosing. If no equation is deemed suitable, this review will form a basis for future studies of GFR in obese individuals. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018104345.
Subject(s)
Glomerular Filtration Rate , Obesity/physiopathology , Humans , Obesity/complications , Renal Insufficiency, Chronic/diagnosis , Renal Insufficiency, Chronic/etiology , Renal Insufficiency, Chronic/physiopathology , Reproducibility of Results , Systematic Reviews as TopicABSTRACT
Hundreds of genetic variants have been associated with Body Mass Index (BMI) through genome-wide association studies (GWAS) using observational cohorts. However, the genetic contribution to efficient weight loss in response to dietary intervention remains unknown. We perform a GWAS in two large low-caloric diet intervention cohorts of obese participants. Two loci close to NKX6.3/MIR486 and RBSG4 are identified in the Canadian discovery cohort (n = 1166) and replicated in the DiOGenes cohort (n = 789). Modulation of HGTX (NKX6.3 ortholog) levels in Drosophila melanogaster leads to significantly altered triglyceride levels. Additional tissue-specific experiments demonstrate an action through the oenocytes, fly hepatocyte-like cells that regulate lipid metabolism. Our results identify genetic variants associated with the efficacy of weight loss in obese subjects and identify a role for NKX6.3 in lipid metabolism, and thereby possibly weight control.
Subject(s)
Genome-Wide Association Study , Homeodomain Proteins/metabolism , Transcription Factors/metabolism , Weight Loss/genetics , Adult , Animals , Bayes Theorem , Cohort Studies , Drosophila Proteins/genetics , Drosophila melanogaster/metabolism , Female , Homeodomain Proteins/genetics , Humans , Male , Middle Aged , Polymorphism, Single Nucleotide/genetics , Risk Factors , Transcription Factors/genetics , Triglycerides/metabolismABSTRACT
AIMS: To identify genetic variants that have a regulatory impact on circulating microRNAs (miRNAs) and to connect genetic risk to blood traits/biomarkers through the circulating miRNAs. METHODS AND RESULTS: Leveraging miRNA-Seq data and the 1000 Genomes imputed genotypes, we carried out genome-wide association analysis for SNPs that regulate the expression of circulating miRNAs in a sample of 710 unrelated subjects of European ancestry. Wherever possible, we used data from the Framingham and the Geuvadis studies to replicate our findings. We found at least one genome-wide significant (P < 5e-8) miRNA-eQTL (mirQTL) for 143 circulating miRNAs. Overall each mirQTL explained a small portion (<1%) of variation in miRNA levels; however, we identified a few mirQTLs that explained 4% to 20% of variation in miRNA levels in plasma. Unlike trans-mirQTLs (P = 0.7), cis-mirQTLs tend to be also associated with their counterpart mature miRNAs (P < 0.0001), this suggests trans-mirQTLs exert their effect through processes that affect the stability of mature miRNAs; whereas, cis-mirQTLs mainly regulate the expression of primary-miRNAs. Next, we used the identified mirQTLs to investigate the links between circulating miRNAs with blood traits/biomarkers through Mendelian randomization analysis. We found miR-1908-5p plays an important role in regulating low-density lipoprotein (LDL), total cholesterol (TC), fasting glucose, HbA1c, and several lipid-metabolites in blood, whereas, miR-10b-5p mediates the trans-regulatory effect of the ABO locus on several blood proteins, coronary artery disease, and TC. Moreover, we demonstrated that a higher plasma level of miR-199a is causally associated with lower levels of LDL and TC. Finally, we found miR-143-3p and miR-145-5p are functionally related and mediate the effect of ZFPM2 on a number of its protein targets in blood including VEGFA, SERPINE1, and PDGFs. CONCLUSIONS: This study identifies SNPs that have a regulatory impact on circulating miRNAs, and underlines the role of several circulating miRNAs in mediating the effect of a number of GWAS loci on cardiometabolic phenotypes.
Subject(s)
Circulating MicroRNA/genetics , Energy Metabolism/genetics , Myocardium/metabolism , Polymorphism, Single Nucleotide , Quantitative Trait Loci , Biomarkers/blood , Blood Glucose/metabolism , Circulating MicroRNA/blood , Female , Gene Regulatory Networks , Genome-Wide Association Study , Genotype , Glycated Hemoglobin/metabolism , Humans , Insulin/blood , Lipids/blood , Male , Mendelian Randomization Analysis , MicroRNAs/blood , MicroRNAs/genetics , Middle Aged , Phenotype , RNA-Seq , White People/geneticsABSTRACT
Holistic human proteome maps are expected to complement comprehensive profile assessment of health and disease phenotypes. However, methodologies to analyze proteomes in human tissue or body fluid samples at relevant scale and performance are still limited in clinical research. Their deployment and demonstration in large enough human populations are even sparser. In the present study, we have characterized and compared the plasma proteomes of two large independent cohorts of obese and overweight individuals using shotgun mass spectrometry (MS)-based proteomics. Herein, we showed, in both populations from different continents of about 500 individuals each, the concordance of plasma protein MS measurements in terms of variability, gender-specificity, and age-relationship. Additionally, we replicated several known and new associations between proteins, clinical and molecular variables, such as insulin and glucose concentrations. In conclusion, our MS-based analyses of plasma samples from independent human cohorts proved the practical feasibility and efficiency of a large and unified discovery/replication approach in proteomics, which was also recently coined "rectangular" design.