Distinct subpopulations of human subcutaneous adipose tissue precursor cells revealed by single-cell RNA sequencing

Adipose-derived stem cells (ADSCs) play an important role in the differential capacity for excess energy storage between upper body abdominal (ABD) adipose tissue (AT) and lower body gluteofemoral (GF) AT. We cultured ADSCs from subcutaneous ABD AT and GF AT isolated from eight women with differential body fat distribution and performed single-cell RNA sequencing. Six populations of ADSCs were identified and segregated according to their anatomical origin. The three ADSC subpopulations in GF AT were characterized by strong cholesterol/fatty acid (FA) storage and proliferation signatures. The two ABD subpopulations, differentiated by higher expression of committed preadipocyte marker genes, were set apart by differential expression of extracellular matrix and ribosomal genes. The last population, identified in both depots, was similar to smooth muscle cells and when individually isolated and cultured in vitro they differentiated less than the other subpopulations. This work provides important insight into the use of ADSC as an in vitro model of adipogenesis and suggests that specific subpopulations of GF-ADSCs contribute to the more robust capacity for GF-AT to expand and grow compared with ABD-AT in women.NEW & NOTEWORTHY Identification of distinct subpopulations of adipose-derived stem cells (ADSCs) in upper body abdominal subcutaneous (ABD) and lower body gluteofemoral subcutaneous (GF) adipose tissue depots. In ABD-ADSCs, subpopulations are more committed to adipocyte lineage. GF-ADSC subpopulations are enriched for genes involved in lipids and cholesterol metabolism. Similar depot differences were found in stem cell population identified in freshly isolated stoma vascular fraction. The repertoire of ADSCs subpopulations was different in apple-shaped versus pear-shaped women.

Do contaminants compromise the use of recycled nutrients in organic agriculture? A review and synthesis of current knowledge on contaminant concentrations, fate in the environment and risk assessment

Use of nutrients recycled from societal waste streams in agriculture is part of the circular economy, and in line with organic farming principles. Nevertheless, diverse contaminants in waste streams create doubts among organic farmers about potential risks for soil health. Here, we gather the current knowledge on contaminant levels in waste streams and recycled nutrient sources, and discuss associated risks. For potentially toxic elements (PTEs), the input of zinc (Zn) and copper (Cu) from mineral feed supplements remains of concern, while concentrations of PTEs in many waste streams have decreased substantially in Europe. The same applies to organic contaminants, although new chemical groups such as flame retardants are of emerging concern and globally contamination levels differ strongly. Compared to inorganic fertilizers, application of organic fertilizers derived from human or animal feces is associated with an increased risk for environmental dissemination of antibiotic resistance. The risk depends on the quality of the organic fertilizers, which varies between geographical regions, but farmland application of sewage sludge appears to be a safe practice as shown by some studies (e.g. from Sweden). Microplastic concentrations in agricultural soils show a wide spread and our understanding of its toxicity is limited, hampering a sound risk assessment. Methods for assessing public health risks for organic contaminants must include emerging contaminants and potential interactions of multiple compounds. Evidence from long-term field experiments suggests that soils may be more resilient and capable to degrade or stabilize pollutants than often assumed. In view of the need to source nutrients for expanding areas under organic farming, we discuss inputs originating from conventional farms vs. non-agricultural (i.e. societal) inputs. Closing nutrient cycles between agriculture and society is feasible in many cases, without being compromised by contaminants, and should be enhanced, aided by improved source control, waste treatment and sound risk assessments.

Transcriptional Control of Subcutaneous Adipose Tissue by the Transcription Factor CTCF Modulates Heterogeneity in Fat Distribution in Women

Determining the mechanism driving body fat distribution will provide insights into obesity-related health risks. We used functional genomics tools to profile the epigenomic landscape to help infer the differential transcriptional potential of apple- and pear-shaped women's subcutaneous adipose-derived stem cells (ADSCs). We found that CCCTC-binding factor (CTCF) expression and its chromatin binding were increased in ADSCs from pear donors compared to those from apple donors. Interestingly, the pear enriched CTCF binding sites were located predominantly at the active transcription start sites (TSSs) of genes with active histone marks and YY1 motifs and were also associated with pear enriched RNAPII binding. In contrast, apple enriched CTCF binding sites were mainly found at intergenic regions and when identified at TSS, they were enriched with the bivalent chromatin signatures. Altogether, we provide evidence that CTCF plays an important role in differential regulation of subcutaneous ADSCs gene expression and may influence the development of apple vs. pear body shape.

An Atlas of Promoter Chromatin Modifications and HiChIP Regulatory Interactions in Human Subcutaneous Adipose-Derived Stem Cells

The genome of human adipose-derived stem cells (ADSCs) from abdominal and gluteofemoral adipose tissue depots are maintained in depot-specific stable epigenetic conformations that influence cell-autonomous gene expression patterns and drive unique depot-specific functions. The traditional approach to explore tissue-specific transcriptional regulation has been to correlate differential gene expression to the nearest-neighbor linear-distance regulatory region defined by associated chromatin features including open chromatin status, histone modifications, and DNA methylation. This has provided important information; nonetheless, the approach is limited because of the known organization of eukaryotic chromatin into a topologically constrained three-dimensional network. This network positions distal regulatory elements in spatial proximity with gene promoters which are not predictable based on linear genomic distance. In this work, we capture long-range chromatin interactions using HiChIP to identify remote genomic regions that influence the differential regulation of depot-specific genes in ADSCs isolated from different adipose depots. By integrating these data with RNA-seq results and histone modifications identified by ChIP-seq, we uncovered distal regulatory elements that influence depot-specific gene expression in ADSCs. Interestingly, a subset of the HiChIP-defined chromatin loops also provide previously unknown connections between waist-to-hip ratio GWAS variants with genes that are known to significantly influence ADSC differentiation and adipocyte function.

DNA Methylation at ABCG1 and Long-term Changes in Adiposity and Fat Distribution in Response to Dietary Interventions: The POUNDS Lost Trial

OBJECTIVE

To examine whether participants with different levels of diabetes-related DNA methylation at ABCG1 might respond differently to dietary weight loss interventions with long-term changes in adiposity and body fat distribution.

RESEARCH DESIGN AND METHODS

The current study included overweight/obese participants from the POUNDS Lost trial. Blood levels of regional DNA methylation at ABCG1 were profiled by high-resolution methylC-capture sequencing at baseline among 673 participants, of whom 598 were followed up at 6 months and 543 at 2 years. Two-year changes in adiposity and computed tomography-measured body fat distribution were calculated.

RESULTS

Regional DNA methylation at ABCG1 showed significantly different associations with long-term changes in body weight and waist circumference at 6 months and 2 years in dietary interventions varying in protein intake (interaction P < 0.05 for all). Among participants assigned to an average-protein (15%) diet, lower baseline regional DNA methylation at ABCG1 was associated with greater reductions in body weight and waist circumference at 6 months and 2 years, whereas opposite associations were found among those assigned to a high-protein (25%) diet. Similar interaction patterns were also observed for body fat distribution, including visceral adipose tissue, subcutaneous adipose tissue, deep subcutaneous adipose tissue, and total adipose tissue at 6 months and 2 years (interaction P < 0.05 for all).

CONCLUSIONS

Baseline DNA methylation at ABCG1 interacted with dietary protein intake on long-term decreases in adiposity and body fat distribution. Participants with lower methylation at ABCG1 benefitted more in long-term reductions in body weight, waist circumference, and body fat distribution when consuming an average-protein diet.

Reduction of SPARC protects mice against NLRP3 inflammasome activation and obesity

The comprehensive assessment of long-term effects of reducing intake of energy (CALERIE-II; NCT00427193) clinical trial established that caloric restriction (CR) in humans lowers inflammation. The identity and mechanism of endogenous CR-mimetics that can be deployed to control obesity-associated inflammation and diseases are not well understood. Our studies have found that 2 years of 14% sustained CR in humans inhibits the expression of the matricellular protein, secreted protein acidic and rich in cysteine (SPARC), in adipose tissue. In mice, adipose tissue remodeling caused by weight loss through CR and low-protein diet feeding decreased, while high-fat diet-induced (HFD-induced) obesity increased SPARC expression in adipose tissue. Inducible SPARC downregulation in adult mice mimicked CR's effects on lowering adiposity by regulating energy expenditure. Deletion of SPARC in adipocytes was sufficient to protect mice against HFD-induced adiposity, chronic inflammation, and metabolic dysfunction. Mechanistically, SPARC activates the NLRP3 inflammasome at the priming step and downregulation of SPARC lowers macrophage inflammation in adipose tissue, while excess SPARC activated macrophages via JNK signaling. Collectively, reduction of adipocyte-derived SPARC confers CR-like metabolic and antiinflammatory benefits in obesity by serving as an immunometabolic checkpoint of inflammation.

Comprehensive interrogation of human skeletal muscle reveals a dissociation between insulin resistance and mitochondrial capacity

Insulin resistance and blunted mitochondrial capacity in skeletal muscle are often synonymous, however, this association remains controversial. The aim of this study was to perform an in-depth multifactorial comparison of skeletal muscle mitochondrial capacity between individuals who were lean and active (Active, n = 9), individuals with obesity (Obese, n = 9), and individuals with obesity, insulin resistance, and type 2 diabetes (T2D, n = 22). Mitochondrial capacity was assessed by ex vivo mitochondrial respiration with fatty-acid and glycolytic-supported protocols adjusted for mitochondrial content (mtDNA and citrate synthase activity). Supercomplex assembly was measured by Blue Native (BN)-PAGE and immunoblot. Tricarboxylic (TCA) cycle intermediates were assessed with targeted metabolomics. Exploratory transcriptomics and DNA methylation analyses were performed to uncover molecular differences affecting mitochondrial function among the three groups. We reveal no discernable differences in skeletal muscle mitochondrial content, mitochondrial capacity, supercomplex assembly, TCA cycle intermediates, and mitochondrial molecular profiles between obese individuals with and without T2D that had comparable levels of confounding factors (body mass index, age, and aerobic capacity). We highlight that lean, active individuals have greater mitochondrial content, mitochondrial capacity, supercomplex assembly, and TCA cycle intermediates. These phenotypical changes are reflected at the level of DNA methylation and gene transcription. The collective observation of comparable muscle mitochondrial capacity in individuals with obesity and T2D (vs. individuals without T2D) underscores a dissociation from skeletal muscle insulin resistance. Clinical trial number: NCT01911104.NEW & NOTEWORTHY Whether impaired mitochondrial capacity contributes to skeletal muscle insulin resistance is debated. Our multifactorial analysis shows no differences in skeletal muscle mitochondrial content, mitochondrial capacity, and mitochondrial molecular profiles between obese individuals with and without T2D that had comparable levels of confounding factors (BMI, age, aerobic capacity). We highlight that lean, active individuals have enhanced skeletal muscle mitochondrial capacity that is also reflected at the level of DNA methylation and gene transcription.

Development of a Brief Version of the Dissociative Symptoms Scale and the Reliability and Validity of DSS-B Scores in Diverse Clinical and Community Samples

The Dissociative Symptoms Scale (DSS) was developed to assess moderately severe types of dissociation (depersonalization, derealization, gaps in awareness and memory, and dissociative reexperiencing) that would be relevant to a range of clinical populations, including those experiencing trauma-related dissociation. The current study used data from 10 ethnically and racially diverse clinical and community samples (N = 3,879) to develop a brief version of the DSS (DSS-B). Item information curves were examined to identify items with the most precision in measuring above average levels of the latent trait within each subscale. Analyses revealed that the DSS-B preserved the factor structure and content domains of the full scale, and its scores had strong reliability and validity that were comparable to those of scores on the full measure. DSS-B scores showed high levels of measurement invariance across ethnoracial groups. Results indicate that DSS-B scores are reliable and valid in the populations studied.

Non-asbestiform elongate mineral particles and mesothelioma risk: Human and experimental evidence

The presentations in this session of the Monticello II conference were aimed at summarizing what is known about asbestiform and non-asbestiform elongate mineral particles (EMPs) and mesothelioma risks based on evidence from experimental and epidemiology studies. Dr. Case discussed case reports of mesothelioma over the last several decades. Dr. Taioli indicated that the epidemiology evidence concerning non-asbestiform EMPs is weak or lacking, and that progress would be limited unless mesothelioma registries are established. One exception discussed is that of taconite miners, who are exposed to grunerite. Drs. Mandel and Odo noted that studies of taconite miners in Minnesota have revealed an excess rate of mesothelioma, but the role of non-asbestiform EMPs in this excess incidence of mesothelioma is unclear. Dr. Becich discussed the National Mesothelioma Virtual Bank (NMVB), a virtual mesothelioma patient registry that includes mesothelioma patients' lifetime work histories, exposure histories, biospecimens, proteogenomic information, and imaging data that can be used in epidemiology research on mesothelioma. Dr. Bernstein indicated that there is a strong consensus that long, highly durable respirable asbestiform EMPs have the potential to cause mesothelioma, but there is continued debate concerning the biodurability required, and the dimensions (both length and diameter), the shape, and the dose associated with mesothelioma risk. Finally, Dr. Nel discussed how experimental studies of High Aspect Ratio Engineered Nanomaterials have clarified dimensional and durability features that impact disease risk, the impact of inflammation and oxidative stress on the epigenetic regulation of tumor suppressor genes, and the generation of immune suppressive effects in the mesothelioma tumor microenvironment. The session ended with a discussion of future research needs.

[WITHDRAWN] Activation of transsulfuration pathway to maintain cysteine is a thermogenic checkpoint for the conservation of energy

The authors have requested that this preprint be removed from Research Square.

Abortion and Reproductive Freedom: Constitutional and Practical Issues

In Dobbs v. Jackson Women's Health, the Supreme Court reversed constitutional protection for abortion. The law will affect the practice of medicine and patients. Practitioners should understand the decision. Protection for reproductive liberties has a checkered history. Much of the constitutional controversy is over the basis for reproductive rights, "substantive due process," the proposition that substantive rights arise from a procedural guarantee in the fourteenth amendment. The change in constitutional protection for abortion will play out differently among the states. Physicians should be prepared to assist patients with new rules and to participate in the public discussion of reproductive liberties.

Are Apologies a Way to Reduce Malpractice Risks?

Apologies are a means of responding to a medical error. Explanation of information related to the episode often fills a need for the patient and family to feel adequately informed. There are pros and cons related to the apology. The American College of Physicians, the American Medical Association, and the Joint Commission of the Accreditation of Health Care Organization Hospital strongly encourage practitioners to disclose when an error or complication occurs. Apologies can be admissible in the courtroom and much of this is state dependent. An apology will be an integral part of the clinician's armamentarium.

Host-diet-gut microbiome interactions influence human energy balance: a randomized clinical trial

The gut microbiome is emerging as a key modulator of human energy balance. Prior studies in humans lacked the environmental and dietary controls and precision required to quantitatively evaluate the contributions of the gut microbiome. Using a Microbiome Enhancer Diet (MBD) designed to deliver more dietary substrates to the colon and therefore modulate the gut microbiome, we quantified microbial and host contributions to human energy balance in a controlled feeding study with a randomized crossover design in young, healthy, weight stable males and females (NCT02939703). In a metabolic ward where the environment was strictly controlled, we measured energy intake, energy expenditure, and energy output (fecal and urinary). The primary endpoint was the within-participant difference in host metabolizable energy between experimental conditions [Control, Western Diet (WD) vs. MBD]. The secondary endpoints were enteroendocrine hormones, hunger/satiety, and food intake. Here we show that, compared to the WD, the MBD leads to an additional 116 ± 56 kcals (P < 0.0001) lost in feces daily and thus, lower metabolizable energy for the host (89.5 ± 0.73%; range 84.2-96.1% on the MBD vs. 95.4 ± 0.21%; range 94.1-97.0% on the WD; P < 0.0001) without changes in energy expenditure, hunger/satiety or food intake (P > 0.05). Microbial 16S rRNA gene copy number (a surrogate of biomass) increases (P < 0.0001), beta-diversity changes (whole genome shotgun sequencing; P = 0.02), and fermentation products increase (P < 0.01) on an MBD as compared to a WD along with significant changes in the host enteroendocrine system (P < 0.0001). The substantial interindividual variability in metabolizable energy on the MBD is explained in part by fecal SCFAs and biomass. Our results reveal the complex host-diet-microbiome interplay that modulates energy balance.

Isolation of nuclei from frozen human subcutaneous adipose tissue for full-length single-nuclei transcriptional profiling

Automated single-cell dispensing is incompatible with white adipose tissue (WAT) due to lipid-laden adipocytes. Single-nuclei RNA-Seq permits transcriptional profiling of all cells from WAT. Human WAT faces unique technical challenges in isolating nuclei compared to rodent tissue due to greater extra-cellular matrix content and larger lipid droplets. In this protocol, we detail how to isolate nuclei from frozen subcutaneous human WAT for single-nuclei RNA-Seq. For complete information on the generation and use of this protocol, please refer to Whytock et al. (2022).1.

Schwann cells contribute to demyelinating diabetic neuropathy and nerve terminal structures in white adipose tissue

Peripheral neuropathy, which can include axonal degeneration and/or demyelination, impacts adipose tissues with obesity, diabetes, and aging. However, the presence of demyelinating neuropathy had not yet been explored in adipose. Both demyelinating neuropathies and axonopathies implicate Schwann cells (SCs), a glial support cell that myelinates axons and contributes to nerve regeneration after injury. We performed a comprehensive assessment of SCs and myelination patterns of subcutaneous white adipose tissue (scWAT) nerves, and changes across altered energy balance states. We found that mouse scWAT contains both myelinated and unmyelinated nerves and is populated by SCs, including SCs that were associated with synaptic vesicle-containing nerve terminals. BTBR ob/ob mice, a model of diabetic peripheral neuropathy, exhibited small fiber demyelinating neuropathy and alterations in SC marker gene expression in adipose that were similar to obese human adipose. These data indicate that adipose SCs regulate the plasticity of tissue nerves and become dysregulated in diabetes.

Source of nicotinamide governs its metabolic fate in cultured cells, mice, and humans

Metabolic routing of nicotinamide (NAM) to NAD⁺ or 1-methylnicotinamide (MeNAM) has impacts on human health and aging. NAM is imported by cells or liberated from NAD⁺. The fate of ²H₄-NAM in cultured cells, mice, and humans was determined by stable isotope tracing. ²H₄-NAM is an NAD⁺ precursor via the salvage pathway in cultured A549 cells and human PBMCs and in A549 cell xenografts and PBMCs from ²H₄-NAM-dosed mice and humans, respectively. ²H₄-NAM is a MeNAM precursor in A549 cell cultures and xenografts, but not isolated PBMCs. NAM released from NAD⁺ is a poor MeNAM precursor. Additional A549 cell tracer studies yielded further mechanistic insight. NAMPT activators promote NAD⁺ synthesis and consumption. Surprisingly, NAM liberated from NAD⁺ in NAMPT activator-treated A549 cells is also routed toward MeNAM production. Metabolic fate mapping of the dual NAM sources across the translational spectrum (cells, mice, humans) illuminates a key regulatory node governing NAD⁺ and MeNAM synthesis.

Glucagon-like peptide-1/glucagon receptor agonism associates with reduced metabolic adaptation and higher fat oxidation: A randomized trial

OBJECTIVE

This study tested the hypothesis that treatment with the glucagon-like peptide-1/glucagon receptor agonist SAR425899 would lead to a smaller decrease in sleeping metabolic rate (SMR; kilocalories/day) than expected from the loss of lean and fat mass (metabolic adaptation).

METHODS

This Phase 1b, double-blind, randomized, placebo-controlled study was conducted at two centers in inpatient metabolic wards. Thirty-five healthy males and females with overweight and obesity (age = 36.5 ± 7.1 years) were randomized to a calorie-reduced diet (-1000 kcal/d) and escalating doses (0.06-0.2 mg/d) of SAR425899 (n = 17) or placebo (n = 18) for 19 days. SMR was measured by whole-room calorimetry.

RESULTS

Both groups lost weight (-3.68 ± 1.37 kg placebo; -4.83 ± 1.44 kg SAR425899). Those treated with SAR425899 lost more weight, fat mass, and fat free mass (p < 0.05) owing to a greater achieved energy deficit than planned. The SAR425899 group had a smaller reduction in body composition-adjusted SMR (p = 0.002) as compared with placebo, but not 24-hour energy expenditure. Fat oxidation and ketogenesis increased in both groups, with significantly greater increases with SAR425899 (p < 0.05).

CONCLUSIONS

SAR425899 led to reduced selective metabolic adaptation and increased lipid oxidation, which are believed to be beneficial for weight loss and weight-loss maintenance.

Reprogramming the Human Gut Microbiome Reduces Dietary Energy Harvest

The gut microbiome is emerging as a key modulator of host energy balance1. We conducted a quantitative bioenergetics study aimed at understanding microbial and host factors contributing to energy balance. We used a Microbiome Enhancer Diet (MBD) to reprogram the gut microbiome by delivering more dietary substrates to the colon and randomized healthy participants into a within-subject crossover study with a Western Diet (WD) as a comparator. In a metabolic ward where the environment was strictly controlled, we measured energy intake, energy expenditure, and energy output (fecal, urinary, and methane)2. The primary endpoint was the within-participant difference in host metabolizable energy between experimental conditions. The MBD led to an additional 116 ± 56 kcals lost in feces daily and thus, lower metabolizable energy for the host by channeling more energy to the colon and microbes. The MBD drove significant shifts in microbial biomass, community structure, and fermentation, with parallel alterations to the host enteroendocrine system and without altering appetite or energy expenditure. Host metabolizable energy on the MBD had quantitatively significant interindividual variability, which was associated with differences in the composition of the gut microbiota experimentally and colonic transit time and short-chain fatty acid absorption in silico. Our results provide key insights into how a diet designed to optimize the gut microbiome lowers host metabolizable energy in healthy humans.

Conceptualising social wellbeing using an international Group Concept Mapping study

Physical, mental and social components of wellbeing are known to be important to health. However, in health research and practice much of the focus has been on physical and mental wellbeing with less attention paid to social components, which we assert detrimentally affects the development of health policies and practices. A systematic measure of wellbeing, which captures both mental (internal) and social (external) wellbeing is needed to offer a richer, nuanced, and more complex multi-dimensional account of wellbeing. We report on using Group Concept Mapping (GCM) to define a social conception of wellbeing. The aim was to capture the complex multi-dimensional aspects of the ‘social resources’ that people access, and the ‘social worlds’ they inhabit. We highlight why it is necessary to separate and promote different components of wellbeing simultaneously, and why a multi-dimensional definition of social wellbeing is needed. We discuss the importance of promoting social wellbeing in health and social care settings, with reference to social prescribing. The paper demonstrates how a theoretically coherent and workable conception of social wellbeing may support scale development i.e., the South Wales Social Wellbeing Scale (SWSWBS). It is anticipated that such a tool would measure the quality of respondents’ overall experience of social wellbeing via the external social resources they possess, their perceived ability to engage in and enjoy the social world in which they live, and, as a result, their capacity for human functioning and flourishing.

Aerobic training increases mitochondrial respiratory capacity in human skeletal muscle stem cells from sedentary individuals

The impact of aerobic training on human skeletal muscle cell (HSkMC) mitochondrial metabolism is a significant research gap, critical to understanding the mechanisms by which exercise augments skeletal muscle metabolism. We therefore assessed mitochondrial content and capacity in fully differentiated CD56+ HSkMCs from lean active (LA) and sedentary individuals with obesity (OS) at baseline, as well as lean/overweight sedentary individuals (LOS) at baseline and following an 18-day aerobic training intervention. Participants had in vivo skeletal muscle PCr recovery rate by 31P-MRS (mitochondrial oxidative kinetics) and cardiorespiratory fitness (VO2max) assessed at baseline. Biopsies of the vastus lateralis were performed for the isolation of skeletal muscle stem cells. LOS individuals repeated all assessments post-training. HSkMCs were evaluated for mitochondrial respiratory capacity by high resolution respirometry. Data were normalized to two indices of mitochondrial content (CS activity and OXPHOS protein expression) and a marker of total cell count (quantity of DNA).LA individuals had significantly higher VO2max than OS and LOS-Pre training; however, no differences were observed in skeletal muscle mitochondrial capacity, nor in carbohydrate- or fatty acid-supported HSkMC respiratory capacity. Aerobic training robustly increased in vivo skeletal muscle mitochondrial capacity of LOS individuals, as well as carbohydrate-supported HSkMC respiratory capacity. Indices of mitochondrial content and total cell count were similar among the groups and did not change with aerobic training.Our findings demonstrate that bioenergetic changes induced with aerobic training in skeletal muscle in vivo are retained in HSkMCs in vitro without impacting mitochondrial content, suggesting that training improves intrinsic skeletal muscle mitochondrial capacity.

Sleep Disturbance and Changes in Energy Intake and Body Composition During Weight Loss in the POUNDS Lost Trial

To examine associations between sleep disturbance and changes in weight and body composition and the mediating role of changes of appetite and food cravings in the Preventing Overweight Using Novel Dietary Strategies (POUNDS Lost) 2-year weight-loss diet intervention trial, this study included 810 overweight or obese individuals with baseline sleep disturbance assessment who were randomly assigned one of four diets varying in macronutrient composition. Changes in body weight and fat distribution were assessed by DEXA and computed tomography during the 2-year intervention. Participants were asked to provide sleep disturbance levels (no, slight, moderate, or great) at baseline and to recall their sleep disturbances since last visit at 6, 12, 18, and 24 months. Weight loss during the first 6 months was followed by 1.5 years of steady weight regain. Participants with greater sleep disturbance from baseline to 6 months showed significant losses of body weight (Ptrend <0.001) and waist circumference (Ptrend = 0.002) at 6 months, after multivariate adjustment. Compared with individuals without sleep disturbance at all from baseline to 6 months, those with slight, moderate, or great sleep disturbance showed an elevated risk of failure to lose weight (-5% or more loss) at 6 months, when the maximum weight loss was achieved, with an odds ratio of 1.24 (95% CI 0.87, 1.78), 1.27 (95% CI 0.75, 2.13), or 3.12 (95% CI 1.61, 6.03), respectively. In addition, we observed that the repeatedly measured levels of sleep disturbance over 2 years were inversely associated with the overall weight loss rate (weight changes per 6 months) (Ptrend <0.001). Further, sleep disturbances during weight loss from baseline to 6 months and weight regain from 6 months to 24 months were significantly predictive of total fat, total fat mass percent, and trunk fat percent changes during the 2 years. Our results also indicated that food cravings for carbohydrates/starches, fast food fats, and sweets; cravings, prospective consumption, hunger of appetite measurements; and dietary restraint, disinhibition, and hunger subscales measured at 6 months significantly mediated the effects of sleep disturbance on weight loss. In conclusion, our results suggested that more severe sleep disturbance during weight loss was associated with an elevated risk of failure to lose weight during the dietary intervention. Food cravings and eating behaviors may partly mediate these associations.

Unique role for lncRNA HOTAIR in defining depot-specific gene expression patterns in human adipose-derived stem cells

In this study, Erdos et al. investigated the role of HOX transcript antisense intergenic RNA (HOTAIR) in adipose tissue biology. Using three different approaches (silencing of HOTAIR in GF human adipose-derived stem cells [GF hASCs], overexpression of HOTAIR in ABD hASCs, and ChIRP-seq) to localize HOTAIR binding in GF hASC chromatin, they found that HOTAIR binds and modulates expression, both positively and negatively, of genes involved in adipose tissue-specific pathways, including adipogenesis, and demonstrate a unique function for HOTAIR in hASC depot-specific regulation of gene expression.

Accumulation of fat above the waist is an important risk factor in developing obesity-related comorbidities independently of BMI or total fat mass. Deciphering the gene regulatory programs of the adipose tissue precursor cells within upper body or abdominal (ABD) and lower body or gluteofemoral (GF) depots is important to understand their differential capacity for lipid accumulation, maturation, and disease risk. Previous studies identified the HOX transcript antisense intergenic RNA (HOTAIR) as a GF-specific lncRNA; however, its role in adipose tissue biology is still unclear. Using three different approaches (silencing of HOTAIR in GF human adipose-derived stem cells [GF hASCs], overexpression of HOTAIR in ABD hASCs, and ChIRP-seq) to localize HOTAIR binding in GF hASC chromatin, we found that HOTAIR binds and modulates expression, both positively and negatively, of genes involved in adipose tissue-specific pathways, including adipogenesis. We further demonstrate a direct interaction between HOTAIR and genes with high RNAPII binding in their gene bodies, especially at their 3′ ends or transcription end sites. Computational analysis suggests HOTAIR binds preferentially to the 3′ ends of genes containing predicted strong RNA–RNA interactions with HOTAIR. Together, these results reveal a unique function for HOTAIR in hASC depot-specific regulation of gene expression.

Transcriptional and DNA Methylation Signatures of Subcutaneous Adipose Tissue and Adipose-Derived Stem Cells in PCOS Women

Polycystic ovary syndrome (PCOS) is often associated with metabolic syndrome features, including central obesity, suggesting that adipose tissue (AT) is a key organ in PCOS pathobiology. In this study, we compared both abdominal (ABD) and gluteofemoral (GF) subcutaneous AT in women with and without PCOS. ABD and GF subcutaneous ATs from PCOS and BMI/WHR-matched control women were analyzed by RT-qPCR, FACS and histology. ABD and GF adipose-derived stem cell (ASC) transcriptome and methylome were analyzed by RNA-seq and DNA methylation array. Similar to the control group with abdominal obesity, the GF AT of PCOS women showed lower expression of genes involved in lipid accumulation and angiogenesis compared to ABD depot. FACS analysis revealed an increase in preadipocytes number in both AT depots from PCOS. Further pathway analysis of RNA-seq comparisons demonstrated that the ASCs derived from PCOS are pro-inflammatory and exhibit a hypoxic signature in the ABD depot and have lower expression of adipogenic genes in GF depot. We also found a higher CpG methylation level in PCOS compared to control exclusively in GF-ASCs. Our data suggest that ASCs play an important role in the etiology of PCOS, potentially by limiting expansion of the healthy lower-body AT.

Caloric restriction in humans reveals immunometabolic regulators of health span

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

A Pandemic Term With "Highly Charged Issues": The U.S. Supreme Court 2020-2021

The 2020-2021 U.S. Supreme Court Term was expected by experts to be uninteresting, but it proved to be quite the opposite. There were surprising unanimous decisions, and some unexpectedly “highly charged issues.” Several of the decisions will be important to mental health professionals (foster care and the conflict of gay and religious rights, juvenile life sentences, and “community caretaking”), and to health care providers more generally (the Affordable Care Act, Pharmacy Benefit Managers, and COVID cases). Other decisions of general interest included immigration cases, election laws, and college athletics. Some of the most important cases arose in the “Shadow Dockets,” an often-ignored series of orders by the Court. The article discusses the most important cases of the Term (including those in the Shadow Docket), analyzes the meaning of the Term, and looks to the cases to be decided next Term.

Twenty-four hour assessments of substrate oxidation reveal differences in metabolic flexibility in type 2 diabetes that are improved with aerobic training

AIMS/HYPOTHESIS

The aim of this study was to assess metabolic flexibility (MetFlex) in participants with type 2 diabetes within the physiologically relevant conditions of sleeping, the post-absorptive (fasting) state and during meals using 24 h whole-room indirect calorimetry (WRIC) and to determine the impact of aerobic training on these novel features of MetFlex.

METHODS

Normal-weight, active healthy individuals (active; n = 9), obese individuals without type 2 diabetes (ND; n = 9) and obese individuals with type 2 diabetes (n = 23) completed baseline metabolic assessments. The type 2 diabetes group underwent a 10 week supervised aerobic training intervention and repeated the metabolic assessments. MetFlex was assessed by indirect calorimetry in response to insulin infusion and during a 24 h period in a whole-room indirect calorimeter. Indices of MetFlex evaluated by WRIC included mean RQ and RQ kinetic responses after ingesting a standard high-carbohydrate breakfast (RQ_BF) and sleep RQ (RQ_sleep). Muscle mitochondrial energetics were assessed in the vastus lateralis muscle in vivo and ex vivo using ³¹P-magnetic resonance spectroscopy and high-resolution respirometry, respectively.

RESULTS

The three groups had significantly different RQ_sleep values (active 0.823 ± 0.04, ND 0.860 ± 0.01, type 2 diabetes 0.842 ± 0.03; p < 0.05). The active group had significantly faster RQ_BF and more stable RQ_sleep responses than the ND and type 2 diabetes groups, as demonstrated by steeper and flatter slopes, respectively. Following the training intervention, the type 2 diabetes group displayed significantly increased RQ_BF slope. Several indices of RQ kinetics had significant associations with in vivo and ex vivo muscle mitochondrial capacities.

CONCLUSIONS/INTERPRETATION

Twenty-four hour WRIC revealed that physiological RQ responses exemplify differences in MetFlex across a spectrum of metabolic health and correlated with skeletal muscle mitochondrial energetics. Defects in certain features of MetFlex were improved with aerobic training, emphasising the need to assess multiple aspects of MetFlex and disentangle insulin resistance from MetFlex in type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01911104.

FUNDING

This study was funded by the ADA (grant no. 7-13-JF-53).

Reliability of measurements of energy expenditure and substrate oxidation using whole-room indirect calorimetry

OBJECTIVE

This analysis aimed to measure the intraparticipant reliability-the intraclass correlation coefficient-of all the components of daily energy expenditure (EE) (24-hour EE, sleep EE, resting EE, basal EE, and thermic effect of food) over a period of 3 consecutive days in 35 study participants.

METHODS

The components of daily EE and substrate use (respiratory exchange ratio) were measured over 3 consecutive days before and after a 3-week 1,000-kcal/d caloric restriction/weight-loss intervention.

RESULTS

There was a high degree of reliability for sleep EE (96.8%), 24-hour EE (97.8%), basal EE (90.6%), and resting EE (93.2%) during the run-in period. The intraclass correlation coefficient for the follow-up period after weight loss (3.67 ± 1.10 kg) remained high for sleep EE (95.6%), 24-hour EE (100%), basal EE (96.1%), and resting EE (92.5%). The minimal detectable differences in EE were reduced by 30% for both 24-hour EE and sleep EE when comparing 2 days versus 1 day spent in the whole-room indirect calorimeter.

CONCLUSIONS

The reliability of the daily components of EE is very high both prior to and after a weight-loss intervention. We here provide instrumental data for investigators to adequately power studies investigating energy metabolism using whole-room indirect calorimetry.

DNA Methylation as a Marker of Body Shape in Premenopausal Women

Preferential accumulation of fat in the gluteo-femoral (GF) depot (pear shape) rather than in the abdominal (A) depot (apple shape), protects against the development of metabolic diseases but the underlying molecular mechanism is still unknown. Recent data, including our work, suggest that differential epigenetic marking is associated with regulation of genes attributed to distinct fat distribution. Here, we aimed to compare the genomic DNA methylation signatures between apple and pear-shaped premenopausal women. To investigate the contribution of upper and lower body fat, we used paired samples of A-FAT and GF-FAT, analyzed on the BeadChip Methylation Array and quantified the differentially methylated sites between the 2 groups of women. We found unique DNA methylation patterns within both fat depots that are significantly different depending on the body fat distribution. Around 60% of the body shape specific DNA methylation sites identified in adipose tissue are maintained ex vivo in cultured preadipocytes. As it has been reported before in other cell types, we found only a hand full of genes showing coordinated differential methylation and expression levels. Finally, we determined that more than 50% of the body shape specific DNA methylation sites could also be detected in whole blood derived DNA. These data reveal a strong DNA methylation program associated with adipose tissue distribution with the possibility that a simple blood test could be used as a predictive diagnostic indicator of young women who are at increased risk for progressing to the apple body shape with a higher risk of developing obesity related complications. Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02728635 and https://clinicaltrials.gov/ct2/show/NCT02226640, identifiers NCT02728635 and NCT02226640.

An improvement in skeletal muscle mitochondrial capacity with short-term aerobic training is associated with changes in Tribbles 1 expression

Exercise training and physical activity are known to be associated with high mitochondrial content and oxidative capacity in skeletal muscle. Metabolic diseases including obesity and insulin resistance are associated with low mitochondrial capacity in skeletal muscle. Certain transcriptional factors such as PGC-1α are known to mediate the exercise response; however, the precise molecular mechanisms involved in the adaptation to exercise are not completely understood. We performed multiple measurements of mitochondrial capacity both in vivo and ex vivo in lean or overweight individuals before and after an 18-day aerobic exercise training regimen. These results were compared to lean, active individuals. Aerobic training in these individuals resulted in a marked increase in mitochondrial oxidative respiratory capacity without an appreciable increase in mitochondrial content. These adaptations were associated with robust transcriptome changes. This work also identifies the Tribbles pseudokinase 1, TRIB1, as a potential mediator of the exercise response in human skeletal muscle.

Metabolic adaptation characterizes short-term resistance to weight loss induced by a low-calorie diet in overweight/obese individuals

BACKGROUND

Low-calorie diet (LCD)-induced weight loss demonstrates response heterogeneity. Physiologically, a decrease in energy expenditure lower than what is predicted based on body composition (metabolic adaptation) and/or an impaired capacity to increase fat oxidation may hinder weight loss. Understanding the metabolic components that characterize weight loss success is important for optimizing weight loss strategies.

OBJECTIVES

We tested the hypothesis that overweight/obese individuals who had lower than expected weight loss in response to a 28-d LCD would be characterized by 1) impaired fat oxidation and 2) whole-body metabolic adaptation. We also characterized the molecular mechanisms associated with weight loss success/failure.

METHODS

This was a retrospective comparison of participants who met their predicted weight loss targets [overweight/obese diet sensitive (ODS), n = 23, females = 21, males = 2] and those that did not [overweight/obese diet resistant (ODR), n = 14, females = 12, males = 2] after a 28-d LCD (900-1000 kcal/d). We used whole-body (energy expenditure and fat oxidation) and tissue-specific measurements (metabolic proteins in skeletal muscle, gene expression in adipose tissue, and metabolites in serum) to detect metabolic properties and biomarkers associated with weight loss success.

RESULTS

The ODR group had greater mean ± SD metabolic adaptation (-175 ± 149 kcal/d; +119%) than the ODS group (-80 ± 108 kcal/d) after the LCD (P = 0.030). Mean ± SD fat oxidation increased similarly for both groups from baseline (0.0701 ± 0.0206 g/min) to day 28 (0.0869 ± 0.0269 g/min; P < 0.001). A principal component analysis factor comprised of serum 3-hydroxybutyric acid, citrate, leucine/isoleucine, acetyl-carnitine, and 3-hydroxylbutyrlcarnitine was associated with weight loss success at day 28 (std. β = 0.674, R2 = 0.479, P < 0.001).

CONCLUSIONS

Individuals who achieved predicted weight loss targets after a 28-d LCD were characterized by reduced metabolic adaptation. Accumulation of metabolites associated with acetyl-CoA excess and enhanced ketogenesis was identified in the ODS group.This trial was registered at clinicaltrials.gov as NCT01616082.

A Metabolomic Signature of Glucagon Action in Healthy Individuals With Overweight/Obesity

Context

Glucagon is produced and released from the pancreatic alpha-cell to regulate glucose levels during periods of fasting. The main target for glucagon action is the liver, where it activates gluconeogenesis and glycogen breakdown; however, glucagon is postulated to have other roles within the body.

Objective

We sought to identify the circulating metabolites that would serve as markers of glucagon action in humans.

Methods

In this study (NCT03139305), we performed a continuous 72-hour glucagon infusion in healthy individuals with overweight/obesity. Participants were randomized to receive glucagon 12.5 ng/kg/min (GCG 12.5), glucagon 25 ng/kg/min (GCG 25), or a placebo control. A comprehensive metabolomics analysis was then performed from plasma isolated at several time points during the infusion to identify markers of glucagon activity.

Results

Glucagon (GCG 12.5 and GCG 25) resulted in significant changes in the plasma metabolome as soon as 4 hours following infusion. Pathways involved in amino acid metabolism were among the most affected. Rapid and sustained reduction of a broad panel of amino acids was observed. Additionally, time-dependent changes in free fatty acids and diacylglycerol and triglyceride species were observed.

Conclusion

These results define a distinct signature of glucagon action that is broader than the known changes in glucose levels. In particular, the robust changes in amino acid levels may prove useful to monitor changes induced by glucagon in the context of additional glucagon-like peptide-1 or gastric inhibitory polypeptide treatment, as these agents also elicit changes in glucose levels.

Prolonged Glucagon Infusion Does Not Affect Energy Expenditure in Individuals with Overweight/Obesity: A Randomized Trial

OBJECTIVE

The aim of this study was to determine the effects of prolonged (72 hours) glucagon administration at a low dose (LD) (12.5 ng/kg/min) and high dose (HD) (25 ng/kg/min) on energy expenditure (EE) in healthy individuals with overweight or obesity.

METHODS

Thirty-one healthy participants with overweight or obesity (BMI of 27-45 kg/m² , 26-55 years old, 23 females) were randomized into LD, HD, or placebo groups and underwent 72-hour intravenous infusion of glucagon. Whole-room calorimetry was used to assess EE and substrate use during five overnight stays (2 days at baseline, 3 days of infusion) and during two 24-hour stays (baseline vs. day 3). Blood was sampled at regular intervals throughout the inpatient stay and analyzed for glucagon and biomarkers of metabolism.

RESULTS

HD infusion elevated plasma glucagon levels compared with the placebo and LD infusion (P < 0.001). Sleeping, basal, and 24-hour EE was not significantly different among groups at any time point. Those receiving HD had significantly higher basal fat oxidation (Fat Ox) at days 2 and 3 than those receiving the placebo (P < 0.05); however, no differences in 24-hour Fat Ox were observed among groups (baseline vs. day 3).

CONCLUSIONS

An HD plasma glucagon infusion over 72 hours does not increase any aspects of EE in healthy individuals with overweight or obesity.

Physiology of Energy Expenditure in the Weight-Reduced State

Although many individuals achieve weight loss of 10% or more, the ability to maintain a reduced body mass over months and years is much rarer. Unfortunately, our understanding of the adverse consequences of having overweight and obesity argues that long-term maintenance of a reduced weight provides the greatest health benefit. However, to achieve long-term weight reduction requires overcoming neuroendocrine systems that favor restoration of one's initial weight. Identifying and characterizing the components of these systems will be important if we are to develop therapies and strategies to reduce the rates of obesity and its complications in our modern society. During this session, Eric Ravussin and Steven R. Smith, respectively, discussed the physiology of the weight-reduced state that favors weight regain and a molecular component that contributes to this response.

Energy intake as a short-term biomarker for weight loss in adults with obesity receiving liraglutide: A randomized trial

Background and Objective

Obesity is a chronic disease associated with many serious comorbidities. Pharmacologic therapies are approved for the treatment of obesity; however, short‐term biomarkers to predict weight loss are not well understood. This study aimed to determine the ability of single‐meal energy intake (EI) to predict weight loss in participants with obesity treated with liraglutide.

Methods

In this randomized, double‐blind, placebo‐controlled study, participants received subcutaneous liraglutide (titrated to 3.0 mg/day) or placebo once daily, with inpatient assessments at baseline and weeks 3 and 6. The primary endpoint was change from baseline (CFB) in EI during consecutive ad libitum lunch meals at weeks 3 and 6. Secondary endpoints included CFB in 24‐ and 48‐h EI, weight, appetite scores, and gastric emptying measures.

Results

Sixty‐one participants were randomized (n = 32, liraglutide; n = 29, placebo). The least squares mean (LSM) difference (95% CI; p‐value) in CFB in EI during ad libitum lunch meals between the liraglutide and placebo groups was −236 (−322, −149; p < 0.0001) kcal at week 3 and –244 (−339, −148, p < 0.0001) kcal at week 6. The liraglutide group experienced significant weight loss at weeks 3 and 6, compared with placebo. Weight loss was significantly correlated with EI, but not with appetite score or gastric emptying.

Conclusions

EI during a single meal is a robust clinical predictor of weight changes in participants with obesity. Future clinical trials can utilize EI at a single meal as a predictor of weight loss.

Chemical Oxygen Demand Can Be Converted to Gross Energy for Food Items Using a Linear Regression Model

BACKGROUND

Human and microbial metabolism are distinct disciplines. Terminology, metrics, and methodologies have been developed separately. Therefore, combining the 2 fields to study energetic processes simultaneously is difficult.

OBJECTIVES

When developing a mechanistic framework describing gut microbiome and human metabolism interactions, energy values of food and digestive materials that use consistent and compatible metrics are required. As an initial step toward this goal, we developed and validated a model to convert between chemical oxygen demand (COD) and gross energy (${E_g}$) for >100 food items and ingredients.

METHODS

We developed linear regression models to relate (and be able to convert between) theoretical gross energy (${E_g}^{\prime}$) and chemical oxygen demand (COD'); the latter is a measure of electron equivalents in the food's carbon. We developed an overall regression model for the food items as a whole and separate regression models for the carbohydrate, protein, and fat components. The models were validated using a sample set of computed ${E_g}^{\prime}$ and COD' values, an experimental sample set using measured ${E_g}$ and COD values, and robust statistical methods.

RESULTS

The overall linear regression model and the carbohydrate, protein, and fat regression models accurately converted between COD and ${E_g}$, and the component models had smaller error. Because the ratios of COD per gram dry weight were greatest for fats and smallest for carbohydrates, foods with a high fat content also had higher ${E_g}$ values in terms of kcal · g dry weight-1.

CONCLUSION

Our models make it possible to analyze human and microbial energetic processes in concert using a single unit of measure, which fills an important need in the food-nutrition-metabolism-microbiome field. In addition, measuring COD and using the regressions to calculate ${E_g}$ can be used instead of measuring ${E_g}$ directly using bomb calorimetry, which saves time and money.

Supreme Court 2019-2020: Insanity, Discrimination, and DACA-And a Pandemic

The 2019–2020 Supreme Court session was an extraordinary session. One major ruling involved insanity defense and whether the two prongs of cognitive capacity and moral capacity were required. Sexual identity was ruled to be covered by the Civil Rights Act in relation to employment. Unanimous criminal jury decisions were ruled a required condition for conviction. The rescindment of DACA was overturned on procedural grounds. Other decisions related to conditions of abortion, habitual residence in international custody cases, police immunity from civil liability, guns, HIV, and capital punishment. Thirty-five percent of cases were unanimous (down from the recent average), and 22% were decided by a 5–4 vote (slightly above the recent average).

A Novel Endocrine Role for the BAT-Released Lipokine 12,13-diHOME to Mediate Cardiac Function

BACKGROUND

Brown adipose tissue (BAT) is an important tissue for thermogenesis, making it a potential target to decrease the risks of obesity, type 2 diabetes, and cardiovascular disease, and recent studies have also identified BAT as an endocrine organ. Although BAT has been implicated to be protective in cardiovascular disease, to this point there are no studies that identify a direct role for BAT to mediate cardiac function.

METHODS

To determine the role of BAT on cardiac function, we utilized a model of BAT transplantation. We then performed lipidomics and identified an increase in the lipokine 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME). We utilized a mouse model with sustained overexpression of 12,13-diHOME and investigated the role of 12,13-diHOME in a nitric oxide synthase type 1 deficient (NOS1^-/-) mouse and in isolated cardiomyocytes to determine effects on function and respiration. We also investigated 12,13-diHOME in a cohort of human patients with heart disease.

RESULTS

Here, we determined that transplantation of BAT (+BAT) improves cardiac function via the release of the lipokine 12,13-diHOME. Sustained overexpression of 12,13-diHOME using tissue nanotransfection negated the deleterious effects of a high-fat diet on cardiac function and remodeling, and acute injection of 12,13-diHOME increased cardiac hemodynamics via direct effects on the cardiomyocyte. Furthermore, incubation of cardiomyocytes with 12,13-diHOME increased mitochondrial respiration. The effects of 12,13-diHOME were absent in NOS1^-/- mice and cardiomyocytes. We also provide the first evidence that 12,13-diHOME is decreased in human patients with heart disease.

CONCLUSIONS

Our results identify an endocrine role for BAT to enhance cardiac function that is mediated by regulation of calcium cycling via 12,13-diHOME and NOS1.

Integrative and quantitative bioenergetics: Design of a study to assess the impact of the gut microbiome on host energy balance

The literature is replete with clinical studies that characterize the structure, diversity, and function of the gut microbiome and correlate the results to different disease states, including obesity. Whether the microbiome has a direct impact on obesity has not been established. To address this gap, we asked whether the gut microbiome and its bioenergetics quantitatively change host energy balance. This paper describes the design of a randomized crossover clinical trial that combines outpatient feeding with precisely controlled metabolic phenotyping in an inpatient metabolic ward. The target population was healthy, weight-stable individuals, age 18-45 and with a body mass index ≤30 kg/m2. Our primary objective was to determine within-participant differences in energy balance after consuming a control Western Diet versus a Microbiome Enhancer Diet intervention specifically designed to optimize the gut microbiome for positive impacts on host energy balance. We assessed the complete energy-balance equation via whole-room calorimetry, quantified energy intake, fecal energy losses, and methane production. We implemented conditions of tight weight stability and balance between metabolizable energy intake and predicted energy expenditure. We explored key factors that modulate the balance between host and microbial nutrient accessibility by measuring enteroendocrine hormone profiles, appetite/satiety, gut transit and gastric emptying. By integrating these clinical measurements with future bioreactor experiments, gut microbial ecology analysis, and mathematical modeling, our goal is to describe initial cause-and-effect mechanisms of gut microbiome metabolism on host energy balance. Our innovative methods will enable subsequent studies on the interacting roles of diet, the gut microbiome, and human physiology.

CLINICALTRIALSGOV IDENTIFIER

NCT02939703. The present study reference can be found here: https://clinicaltrials.gov/ct2/show/NCT02939703.

C-reactive protein trajectory to predict colorectal anastomotic leak: PREDICT Study

BACKGROUND

Anastomotic leak is a common complication after colorectal surgery, associated with increased morbidity and mortality, and poorer long-term survival after oncological resections. Early diagnosis improves short-term outcomes, and may translate into reduced cancer recurrence. Multiple studies have attempted to identify biomarkers to enable earlier diagnosis of anastomotic leak. One study demonstrated that the trajectory of C-reactive protein (CRP) levels was highly predictive of anastomotic leak requiring intervention, with an area under the curve of 0·961. The aim of the present study was to validate this finding externally.

METHODS

This was a prospective international multicentre observational study of adults undergoing elective colorectal resection with an anastomosis. CRP levels were measured before operation and for 5 days afterwards, or until day of discharge if earlier than this. The primary outcome was anastomotic leak requiring operative or radiological intervention.

RESULTS

Between March 2017 and July 2018, 933 patients were recruited from 20 hospitals across Australia, New Zealand, England and Scotland. Some 833 patients had complete CRP data and were included in the primary analysis, of whom 41 (4·9 per cent) developed an anastomotic leak. A change in CRP level exceeding 50 mg/l between any two postoperative days had a sensitivity of 0·85 for detecting a leak, and a high negative predictive value of 0·99 for ruling it out. A change in CRP concentration of more than 50 mg/l between either days 3 and 4 or days 4 and 5 after surgery had a high specificity of 0·96-0·97, with positive likelihood ratios of 4·99-6·44 for a leak requiring intervention.

CONCLUSION

This study confirmed the value of CRP trajectory in accurately ruling out an anastomotic leak after colorectal resection.

Fat Distribution in Women Is Associated With Depot-Specific Transcriptomic Signatures and Chromatin Structure

BACKGROUND

Preferential accumulation of fat in the upper body (apple shape) is associated with higher risk of developing metabolic syndrome relative to lower body fat (pear shape). We previously discovered that chromatin openness partially defined the transcriptome of preadipocytes isolated from abdominal and gluteofemoral fat. However, the molecular mechanisms underlying interindividual variation in body shape are unknown.

METHODS

Adipocyte fraction was isolated from abdominal and gluteofemoral fat biopsies of premenopausal women (age and body mass index matched) segregated initially only by their waist-to-hip ratio. We evaluated transcriptomic and chromatin accessibility using RNA sequencing and assay for transposase-accessible chromatin using sequencing (ATAC-seq) along with key clinical parameters.

RESULTS

Our data showed that higher lower body fat mass was associated with better lipid profile and free fatty acid decrease after glucose administration. Lipid and glucose metabolic pathways genes were expressed at higher levels in gluteofemoral adipocyte fraction in pears, whereas genes associated with inflammation were higher both in abdominal and gluteofemoral apple adipocyte fraction. Gluteofemoral adipocyte chromatin from pear-shaped women contained a significantly higher number of differentially open ATAC-seq peaks relative to chromatin from the apple-shaped gluteofemoral adipocytes. In contrast, abdominal adipocyte chromatin openness showed few differences between apple- and pear-shaped women. We revealed a correlation between gene transcription and open chromatin at the proximity of the transcriptional start site of some of the differentially expressed genes.

CONCLUSIONS

Integration of data from all 3 approaches suggests that chromatin openness partially governs the transcriptome of gluteofemoral adipocytes and may be involved in the early metabolic syndrome predisposition associated with body shape.

Plasma Myokine Concentrations After Acute Exercise in Non-obese and Obese Sedentary Women

Exercise and physical activity levels influence myokine release from skeletal muscle and contribute to circulating concentrations. Indeed, many myokines, including interleukin (IL)-6, IL-15, secreted protein acidic rich in cysteine (SPARC), and fibroblast growth factor (FGF) 21 are higher in the circulation after an exercise bout. Since these peptides modulate muscle metabolism and can also be targeted toward other tissues to induce adaptations to energy demand, they are of great interest regarding metabolic diseases. Therefore, we set out to compare, in six women with obesity (BMI ≥30 kg/m²) and five healthy women (BMI 22–29.9 kg/m²), the effect of an acute bout of moderate-intensity, continuous cycling exercise (60 min, 60% VO₂peak) on the release of myokines (IL-6, IL-8, IL-10, IL-13, IL-15, SPARC, and FGF21) in plasma for a 24-h time course. We found that plasma IL-8 and SPARC levels were reduced in the group of women with obesity, whereas plasma IL-13 concentrations were elevated in comparison to non-obese women both before and after the exercise bout. We also found that plasma FGF21 concentration during the 24 h following the bout of exercise was regulated differently in the non-obese in comparison to obese women. Plasma concentrations of FGF21, IL-6, IL-8, IL-15, and IL-18 were regulated by acute exercise. Our results confirm the results of others concerning exercise regulation of circulating myokines while providing insight into the time course of myokine release in circulation after an acute exercise bout and the differences in circulating myokines after exercise in women with or without obesity.

Lorcaserin and Renal Outcomes in Obese and Overweight Patients in the CAMELLIA-TIMI 61 Trial

BACKGROUND

Obesity is thought to increase renal hyperfiltration, thereby increasing albuminuria and the progression of renal disease. The effect of pharmacologically mediated weight loss on renal outcomes is not well-described. Lorcaserin, a selective serotonin 2C receptor agonist that promotes appetite suppression, led to sustained weight loss without any increased risk for major adverse cardiovascular (CV) events in the CAMELLIA-TIMI 61 trial (Cardiovascular and Metabolic Effects of Lorcaserin in Overweight and Obese Patients-Thrombolysis in Myocardial Infarction 61).

METHODS

CAMELLIA-TIMI 61 randomly assigned 12 000 overweight or obese patients with or at high risk for atherosclerotic CV disease to lorcaserin or placebo on a background of lifestyle modification. The primary renal outcome was a composite of new or worsening persistent micro- or macroalbuminuria, new or worsening chronic kidney disease, doubling of serum creatinine, end-stage renal disease, renal transplant, or renal death.

RESULTS

At baseline, 23.8% of patients had an estimated glomerular filtration rate (eGFR) <60 mL·min^-1·1.73 m^-2 and 19.0% had albuminuria (urinary albumin:creatinine ratio ≥30 mg/g). Lorcaserin reduced the risk of the primary renal composite outcome (4.2% per year versus 4.9% per year; hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.79-0.96; P=0.0064). The benefit was consistent across subpopulations at increased baseline CV and renal risk. Lorcaserin improved both eGFR and urinary albumin:creatinune ratio within the first year after randomization. The effect of lorcaserin on weight, hemoglobin A1c, and systolic blood pressure was consistent regardless of baseline renal function. Likewise, there was no excess in cardiovascular events in patients assigned to lorcaserin in comparison with placebo, regardless of renal function. After adjustment for baseline characteristics, those with evidence of kidney disease were at increased risk of major CV events. Compared with patients with an eGFR ≥90 mL·min^-1·1.73 m^-2, those with an eGFR 60-90 and those <60 mL·min^-1·1.73 m-2 had HRs of 1.25 (95% CI, 1.01, 1.56) and 1.51 (95% CI, 1.17, 1.95), respectively ( P for trend 0.0015). Likewise, compared with patients with no albuminuria (<30 mg/g), those microalbuminuria and those with macroalbuminuria had HRs of 1.46 (95% CI, 1.22, 1.74) and 2.10 (95% CI, 1.58, 2.80), respectively ( P for trend <0.0001).

CONCLUSIONS

Renal dysfunction was associated with increased CV risk in overweight and obese patients. When added to diet and lifestyle, lorcaserin reduced the rate of new-onset or progressive renal impairment in comparison with placebo.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02019264.

Endurance training remodels skeletal muscle phospholipid composition and increases intrinsic mitochondrial respiration in men with Type 2 diabetes

The effects of exercise training on the skeletal muscle (SKM) lipidome and mitochondrial function have not been thoroughly explored in individuals with Type 2 diabetes (T2D). We hypothesize that 10 wk of supervised endurance training improves SKM mitochondrial function and insulin sensitivity that are related to alterations in lipid signatures within SKM of T2D (males n = 8). We employed integrated multi-omics data analyses including ex vivo lipidomics (MS/MS-shotgun) and transcriptomics (RNA-Seq). From biopsies of SKM, tissue and primary myotubes mitochondrial respiration were quantified by high-resolution respirometry. We also performed hyperinsulinemic-euglycemic clamps and blood draws before and after the training. The lipidomics analysis revealed that endurance training (>95% compliance) increased monolysocardiolipin by 68.2% (P ≤ 0.03), a putative marker of mitochondrial remodeling, and reduced total sphingomyelin by 44.8% (P ≤ 0.05) and phosphatidylserine by 39.7% (P ≤ 0.04) and tended to reduce ceramide lipid content by 19.8%. Endurance training also improved intrinsic mitochondrial respiration in SKM of T2D without alterations in mitochondrial DNA copy number or cardiolipin content. RNA-Seq revealed 71 transcripts in SKM of T2D that were differentially regulated. Insulin sensitivity was unaffected, and HbA1c levels moderately increased by 7.3% despite an improvement in cardiorespiratory fitness (V̇o_2peak) following the training intervention. In summary, endurance training improves intrinsic and cell-autonomous SKM mitochondrial function and modifies lipid composition in men with T2D independently of alterations in insulin sensitivity and glycemic control.

The LAPLAP study: a randomized placebo-controlled clinical trial assessing postoperative functional recovery using intraperitoneal local anaesthetic in laparoscopic colorectal surgery

AIM

Postoperative pain remains a major factor in recovery from colorectal resection. There is increasing interest in opioid-sparing analgesia, and intraperitoneal local anaesthetic (IPLA) has recently been shown to be useful in minor laparoscopic and open colorectal procedures. The aim of this study was to evaluate the impact of IPLA on functional recovery following major laparoscopic surgery. In this controlled trial, mobility, as measured by the De Morton Mobility Index (DEMMI), was used as a surrogate for postoperative functional recovery.

METHOD

Patients undergoing laparoscopic colorectal resection were randomized either to continuous ropivacaine (0.2% at 4-6 ml/h) or to saline (0.9%) which were administered via intraperitoneal catheter for 3 days postoperatively. Results were analysed in a double-blind manner. DEMMIs were assessed on postoperative days 1, 2, 3, 7 and 30, and data on pain, opioid consumption, gut and respiratory function, length of stay (LOS) and complications were recorded.

RESULTS

Ninety-six patients were recruited. There was no difference in primary outcome (i.e., functional recovery) between IPLA and placebo groups. Opioid consumption and LOS were similar between groups, and no differences were found for any secondary outcome measure. There were no adverse events related to ropivacaine.

CONCLUSION

Infusional intraperitoneal local anaesthetic appears to be safe but does not improve functional recovery or analgesic consumption following elective laparoscopic colorectal surgery, in the setting of an established enhanced recovery programme.

Metabolic adaptation is not observed after 8 weeks of overfeeding but energy expenditure variability is associated with weight recovery

BACKGROUND

A metabolic adaptation, defined as an increase in energy expenditure (EE) beyond what is expected with weight gain during overfeeding (OF), has been reported but also refuted. Much of the inconsistency stems from the difficulty in conducting large, well-controlled OF studies in humans.

OBJECTIVES

The primary aim of this study was to determine whether a metabolic adaptation to OF exists and if so, attenuates weight gain.

METHODS

Thirty-five young adults consumed 40% above their baseline energy requirements for 8 wk, and sleeping metabolic rate (SMR) and 24-h sedentary energy expenditure (24h-EE) were measured before and after OF. Subjects were asked to return for a 6-mo post-OF follow-up visit to measure body weight, body composition, and physical activity.

RESULTS

After adjusting for gains in fat-free mass and fat mass, SMR increased by 43 ± 123 kcal/d more than expected (P = 0.05) and 24h-EE by 23 ± 139 kcal/d (P = 0.34), indicating an overall lack of metabolic adaptation during OF despite a wide variability in the response. Among the 30 subjects who returned for the 6-mo follow-up visit, those who had a lower-than-predicted SMR (basal EE) retained more of the fat gained during OF. Likewise, subjects displaying a higher-than-predicted sedentary 24h-EE lost significantly more fat during the 6-mo follow-up.

CONCLUSIONS

Metabolic adaptation to OF was on average very small but variable between subjects, revealing "thrifty" or "spendthrift" metabolic phenotypes related to body weight loss 6 mo later. This trial was registered at clinicaltrials.gov as NCT01672632.