Relationships between Rodent White Adipose Fat Pads and Human White Adipose Fat Depots

The parasitic worm product ES-62 promotes health- and life-span in a high calorie diet-accelerated mouse model of ageing

Improvements in hygiene and health management have driven significant increases in human lifespan over the last 50 years. Frustratingly however, this extension of lifespan has not been matched by equivalent improvements in late-life health, not least due to the global pandemic in type-2 diabetes, obesity and cardiovascular disease, all ageing-associated conditions exacerbated and accelerated by widespread adoption of the high calorie Western diet (HCD). Recently, evidence has begun to emerge that parasitic worm infection might protect against such ageing-associated co-morbidities, as a serendipitous side-effect of their evolution of pro-survival, anti-inflammatory mechanisms. As a novel therapeutic strategy, we have therefore investigated the potential of ES-62, an anti-inflammatory secreted product of the filarial nematode Acanthocheilonema viteae, to improve healthspan (the period of life before diseases of ageing appear) by targeting the chronic inflammation that drives metabolic dysregulation underpinning ageing-induced ill-health. We administered ES-62 subcutaneously (at a dose of 1 μg/week) to C57BL/6J mice undergoing HCD-accelerated ageing throughout their lifespan, while subjecting the animals to analysis of 120 immunometabolic responses at various time-points. ES-62 improved a number of inflammatory parameters, but markedly, a range of pathophysiological, metabolic and microbiome parameters of ageing were also successfully targeted. Notably, ES-62-mediated promotion of healthspan in male and female HCD-mice was associated with different mechanisms and reflecting this, machine learning modelling identified sex-specific signatures predictive of ES-62 action against HCD-accelerated ageing. Remarkably, ES-62 substantially increased the median survival of male HCD-mice. This was not the case with female animals and unexpectedly, this difference between the two sexes could not be explained in terms of suppression of the chronic inflammation driving ageing, as ES-62 tended to be more effective in reducing this in female mice. Rather, the difference appeared to be associated with ES-62's additional ability to preferentially promote a healthier gut-metabolic tissue axis in male animals.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

Characterization of different adipose depots in fattened buffalo: histological features and expression profiling of adipocyte markers

Adipose tissue (AT) is a multi-depot organ in mammals. AT from various depots differs in composition and function. Revealing the composition feature of AT depots will provide valuable information for further research on the development and fat deposition patterns in buffalo. This study explored the cellular morphology and gene expression profiles of brown and beige markers in seven AT depots of fattened buffalo: three subcutaneous depots (back, sternum, and inguinal) and four visceral depots (perirenal, mesenteric, pericardial, and omental). Histological results showed unilocular adipocytes in all seven AT depots. Uncoupling protein 1 (UCP1) mRNA, a brown and beige adipocyte gene, was detected in all depots with the highest level in VAT depots, and a limited number of UCP1-positive unilocular adipocytes were observed in the three VAT depots. The mRNAs of PPARG coactivator 1 alpha (PGC1 α ) and transmembrane protein 26 (TMEM26), brown or beige adipocyte markers, were identified in all seven depots and were mainly expressed in VAT depots. However, the mRNA of zinc finger protein of the cerebellum 1 (ZIC1), a brown adipocyte-specific marker, was almost undetectable. Our results demonstrated that all seven AT depots are white adipose tissue (WAT), with potential function of non-shivering thermogenesis in fattened buffalo. Beige adipocytes are more active in VAT depots than in WAT depots. These results improve our knowledge on the feature of different adipose tissue depots in buffalo, which will be useful for the research of fat deposition.

Adipose Tissue and Brain Metabolic Responses to Western Diet-Is There a Similarity between the Two?

Dietary fats and sugars were identified as risk factors for overweight and neurodegeneration, especially in middle-age, an earlier stage of the aging process. Therefore, our aim was to study the metabolic response of both white adipose tissue and brain in middle aged rats fed a typical Western diet (high in saturated fats and fructose, HFF) and verify whether a similarity exists between the two tissues. Specific cyto/adipokines (tumor necrosis factor alpha (TNF-α), adiponectin), critical obesity-inflammatory markers (haptoglobin, lipocalin), and insulin signaling or survival protein network (insulin receptor substrate 1 (IRS), Akt, Erk) were quantified in epididymal white adipose tissue (e-WAT), hippocampus, and frontal cortex. We found a significant increase of TNF-α in both e-WAT and hippocampus of HFF rats, while the expression of haptoglobin and lipocalin was differently affected in the various tissues. Interestingly, adiponectin amount was found significantly reduced in e-WAT, hippocampus, and frontal cortex of HFF rats. Insulin signaling was impaired by HFF diet in e-WAT but not in brain. The above changes were associated with the decrease in brain derived neurotrophic factor (BDNF) and synaptotagmin I and the increase in post-synaptic protein PSD-95 in HFF rats. Overall, our investigation supports for the first time similarities in the response of adipose tissue and brain to Western diet.

The role of adipose tissue in cardiovascular health and disease

Accumulating knowledge on the biology and function of the adipose tissue has led to a major shift in our understanding of its role in health and disease. The adipose tissue is now recognized as a crucial regulator of cardiovascular health, mediated by the secretion of several bioactive products, including adipocytokines, microvesicles and gaseous messengers, with a wide range of endocrine and paracrine effects on the cardiovascular system. The adipose tissue function and secretome are tightly controlled by complex homeostatic mechanisms and local cell-cell interactions, which can become dysregulated in obesity. Systemic or local inflammation and insulin resistance lead to a shift in the adipose tissue secretome from anti-inflammatory and anti-atherogenic towards a pro-inflammatory and pro-atherogenic profile. Moreover, the interplay between the adipose tissue and the cardiovascular system is bidirectional, with vascular-derived and heart-derived signals directly affecting adipose tissue biology. In this Review, we summarize the current knowledge of the biology and regional variability of adipose tissue in humans, deciphering the complex molecular mechanisms controlling the crosstalk between the adipose tissue and the cardiovascular system, and their possible clinical translation. In addition, we highlight the latest developments in adipose tissue imaging for cardiovascular risk stratification and discuss how therapeutic targeting of the adipose tissue can improve prevention and treatment of cardiovascular disease.

Adipocyte-progenitor cell communication that influences adipogenesis

Adipose tissue is located in discrete depots that are differentially associated with elevated risk of metabolic complications, with fat accretion in visceral depots being most detrimental to metabolic health. Currently, the regulation of specific adipose depot expansion, by adipocyte hypertrophy and hyperplasia and consequently fat distribution, is not well understood. However, a growing body of evidence from in vitro investigations indicates that mature adipocytes secrete factors that modulate the proliferation and differentiation of progenitor, adipose-derived stem cells (ADSCs). It is therefore plausible that endocrine communication between adipocytes and ADSCs located in different depots influences fat distribution, and may therefore contribute to the adverse health outcomes associated with visceral adiposity. This review will explore the available evidence of paracrine and endocrine crosstalk between mature adipocytes and ADSCs that affects adipogenesis, as a better understanding of the regulatory roles of the extracellular signalling mechanisms within- and between adipose depots may profoundly change the way we view adipose tissue growth in obesity and related comorbidities.

An In Vivo/Ex Vivo Study Design to Investigate Effects of Chronic Conditions and Therapeutic Compounds on Adipose Stem Cells in Animal Models

With the dramatic rise in the global prevalence of obesity and lack of success at addressing this public health issue, there is an urgency to develop new tools with which to study obesity and putative weight-loss products. Pre-adipocyte cell lines have been widely used as a model for adipocyte biology and obesity over the past four decades, but the applicability of results from these cell lines is limited. This chapter will describe an in vivo/ex vivo study design that can be employed to examine the effects of diets and other chronic physiological or pathophysiological conditions on the biology of adipose stem cells (ASCs), as a model for the progression and management of obesity. This type of study design is superior to short-term in vitro experiments in pre-adipocyte cell lines or ASCs, as chronic in vivo conditions cannot be recapitulated in cell culture. Rather, this in vivo/ex vivo study design provides researchers the opportunity to assess the progressive effects of long-term insults or interventions on the reprogramming of ASC behavior. In addition, this model allows us to study the metabolic effects of chronic conditions and therapeutic compounds at a systemic level as well as at the level of adipose tissue and ASCs, in order to provide a whole-body context for the findings.

The Immune Landscape of Visceral Adipose Tissue During Obesity and Aging

Obesity and aging represent major health burdens to the global adult population. Both conditions promote the development of associated metabolic diseases such as insulin resistance. The visceral adipose tissue (VAT) is a site that becomes dysfunctional during obesity and aging, and plays a significant role during their pathophysiology. The changes in obese and aging VAT are now recognized to be partly driven by a chronic local inflammatory state, characterized by immune cells that typically adopt an inflammatory phenotype during metabolic disease. Here, we summarize the current knowledge on the immune cell landscape of the VAT during lean, obese, and aged conditions, highlighting their similarities and differences. We also briefly discuss possible linked mechanisms that fuel obesity- and age-associated VAT dysfunction.

Amelioration of perivascular adipose inflammation reverses vascular dysfunction in a model of nonobese prediabetic metabolic challenge: potential role of antidiabetic drugs

The onset of vascular impairment precedes that of diagnostic hyperglycemia in diabetic patients suggesting a vascular insult early in the course of metabolic dysfunction without a well-defined mechanism. Mounting evidence implicates adipose inflammation in the pathogenesis of insulin resistance and diabetes. It is not certain whether amelioration of adipose inflammation is sufficient to preclude vascular dysfunction in early stages of metabolic disease. Recent findings suggest that antidiabetic drugs, metformin, and pioglitazone, improve vascular function in prediabetic patients, without an indication if this protective effect is mediated by reduction of adipose inflammation. Here, we used a prediabetic rat model with delayed development of hyperglycemia to study the effect of metformin or pioglitazone on adipose inflammation and vascular function. At the end of the metabolic challenge, these rats were neither obese, hypertensive, nor hyperglycemic. However, they showed increased pressor responses to phenylephrine and augmented aortic and mesenteric contraction. Vascular tissues from prediabetic rats showed increased Rho-associated kinase activity causing enhanced calcium sensitization. An elevated level of reactive oxygen species was seen in aortic tissues together with increased Transforming growth factor β1 and Interleukin-1β expression. Although, no signs of systemic inflammation were detected, perivascular adipose inflammation was observed. Adipocyte hypertrophy, increased macrophage infiltration, and elevated Transforming growth factor β1 and Interleukin-1β mRNA levels were seen. Two-week treatment with metformin or pioglitazone or switching to normal chow ameliorated adipose inflammation and vascular dysfunction. Localized perivascular adipose inflammation is sufficient to trigger vascular dysfunction early in the course of diabetes. Interfering with this inflammatory process reverses this early abnormality.

Adipocyte epigenetic alterations and potential therapeutic targets in transgenerationally inherited lean and obese phenotypes following ancestral exposures

The incidence of obesity has increased dramatically over the past two decades with a prevalence of approximately 40% of the adult population within the United States. The current study examines the potential for transgenerational adipocyte (fat cell) epigenetic alterations. Adipocytes were isolated from the gonadal fat pad of the great-grand offspring F3 generation 1-year old rats ancestrally exposed to DDT (dichlorodiphenyltrichloroethane), atrazine, or vehicle control in order to obtain adipocytes for DNA methylation analysis. Observations indicate that there were differential DNA methylated regions (DMRs) in the adipocytes with the lean or obese phenotypes compared to control normal (non-obese or lean) populations. The comparison of epigenetic alterations indicated that there were substantial overlaps between the different treatment lineage groups for both the lean and obese phenotypes. Novel correlated genes and gene pathways associated with DNA methylation were identified, and may aid in the discovery of potential therapeutic targets for metabolic diseases such as obesity. Observations indicate that ancestral exposures during critical windows of development can induce the epigenetic transgenerational inheritance of DNA methylation changes in adipocytes that ultimately may contribute to an altered metabolic phenotype.

Omega-3 polyunsaturated fatty acids have beneficial effects on visceral fat in diet-induced obesity model

This study evaluated the effects of omega-3 polyunsaturated fatty acids (PUFAs) on oxidative stress and energy metabolism parameters in the visceral fat of a high-fat-diet induced obesity model. Energy intake, body mass, and visceral fat mass were also evaluated. Male Swiss mice received either a control diet (control group) or a high-fat diet (obese group) for 6 weeks. After this period, the groups were divided into control + saline, control + omega-3, obese + saline, and obese + omega-3, and to these groups 400 mg·(kg body mass)-1·day-1 of fish oil (or saline) was administered orally, for 4 weeks. Energy intake and body mass were monitored throughout the experiment. In the 10th week, the animals were euthanized and the visceral fat (mesenteric) was removed. Treatment with omega-3 PUFAs did not affect energy intake or body mass, but it did reduced visceral fat mass. In visceral fat, omega-3 PUFAs reduced oxidative damage and alleviated changes to the antioxidant defense system and the Krebs cycle. The mitochondrial respiratory chain was neither altered by obesity nor by omega-3 PUFAs. In conclusion, omega-3 PUFAs have beneficial effects on the visceral fat of obese mice because they mitigate changes caused by the consumption of a high-fat diet.

Adipocyte PU.1 knockout promotes insulin sensitivity in HFD-fed obese mice

Insulin resistance is a key feature of obesity and type 2 diabetes. PU.1 is a master transcription factor predominantly expressed in macrophages but after HFD feeding PU.1 expression is also significantly increased in adipocytes. We generated adipocyte specific PU.1 knockout mice using adiponectin cre to investigate the role of PU.1 in adipocyte biology, insulin and glucose homeostasis. In HFD-fed obese mice systemic glucose tolerance and insulin sensitivity were improved in PU.1 AKO mice and clamp studies indicated improvements in both adipose and liver insulin sensitivity. At the level of adipose tissue, macrophage infiltration and inflammation was decreased and glucose uptake was increased in PU.1 AKO mice compared with controls. While PU.1 deletion in adipocytes did not affect the gene expression of PPARg itself, we observed increased expression of PPARg target genes in eWAT from HFD fed PU.1 AKO mice compared with controls. Furthermore, we observed decreased phosphorylation at serine 273 in PU.1 AKO mice compared with fl/fl controls, indicating that PPARg is more active when PU.1 expression is reduced in adipocytes. Therefore, in obesity the increased expression of PU.1 in adipocytes modifies the adipocyte PPARg cistrome resulting in impaired glucose tolerance and insulin sensitivity.

27-Hydroxycholesterol Promotes Adiposity and Mimics Adipogenic Diet-Induced Inflammatory Signaling

27-Hydroxycholesterol (27HC) is an abundant cholesterol metabolite and has detrimental effects on the cardiovascular system, whereas its impact on adiposity is not well known. In this study, we found that elevations in 27HC cause increased body weight gain in mice fed a high-fat/high-cholesterol diet in an estrogen receptor α-dependent manner. Regardless of diet type, body fat mass was increased by 27HC without changes in food intake or fat absorption. 27HC did not alter energy expenditure in mice fed a normal chow diet and increased visceral white adipose mass by inducing hyperplasia but not hypertrophy. Although 27HC did not augment adipocyte terminal differentiation, it increased the adipose cell population that differentiates to mature adipocytes. RNA sequencing analysis revealed that 27HC treatment of mice fed a normal chow diet induces inflammatory gene sets similar to those seen after high-fat/high-cholesterol diet feeding, whereas there was no overlap in inflammatory gene expression among any other 27HC administration/diet change combination. Histological analysis showed that 27HC treatment increased the number of total and M1-type macrophages in white adipose tissues. Thus, 27HC promotes adiposity by directly affecting white adipose tissues and by increasing adipose inflammatory responses. Lowering serum 27HC levels may lead to an approach targeting cholesterol to prevent diet-induced obesity.

Anti-Obesity Effects of the Flower of Prunus persica in High-Fat Diet-Induced Obese Mice

Prunus persica (L.) Batsch is a deciduous fruit tree cultivated worldwide. The flower of P. persica (PPF), commonly called the peach blossom, is currently consumed as a tea for weight loss in East Asia; however, its anti-obesity effects have yet to be demonstrated in vitro or in vivo. Since PPF is rich in phytochemicals with anti-obesity properties, we aimed to investigate the effects of PPF on obesity and its underlying mechanism using a diet-induced obesity model. Male C57BL/6 mice were fed either normal diet, high-fat diet (HFD), or HFD containing 0.2% or 0.6% PPF water extract for 8 weeks. PPF significantly reduced body weight, abdominal fat mass, serum glucose, alanine transaminase and aspartate aminotransferase levels, and liver and spleen weights compared to the HFD control group. Real-time quantitative polymerase chain reaction analysis revealed that PPF suppressed lipogenic gene expression, including stearoyl-CoA desaturase-1 and -2 and fatty acid synthase, and up-regulated the fatty acid β-oxidation gene, carnitine palmitoyltransferase-1, in the liver. Our results suggest that PPF exerts anti-obesity effects in obese mice and these beneficial effects might be mediated through improved hepatic lipid metabolism by reducing lipogenesis and increasing fatty acid oxidation.

Activation of NPRs and UCP1-independent pathway following CB1R antagonist treatment is associated with adipose tissue beiging in fat-fed male dogs

CB1 receptor (CB1R) antagonism improves the deleterious effects of a high-fat diet (HFD) by reducing body fat mass and adipocyte cell size. Previous studies demonstrated that the beneficial effects of the CB1R antagonist rimonabant (RIM) in white adipose tissue (WAT) are partially due to an increase of mitochondria numbers and upregulation thermogenesis markers, suggesting an induction of WAT beiging. However, the molecular mechanism by which CB1R antagonism induces weight loss and WAT beiging is unclear. In this study, we probed for genes associated with beiging and explored longitudinal molecular mechanisms by which the beiging process occurs. HFD dogs received either RIM (HFD+RIM) or placebo (PL) (HFD+PL) for 16 wk. Several genes involved in beiging were increased in HFD+RIM compared with pre-fat, HFD, and HFD+PL. We evaluated lipolysis and its regulators including natriuretic peptide (NP) and its receptors (NPRs), β-1 and β-3 adrenergic receptor (β1R, β3R) genes. These genes were increased in WAT depots, accompanied by an increase in lipolysis in HFD+RIM. In addition, RIM decreased markers of inflammation and increased adiponectin receptors in WAT. We observed a small but significant increase in UCP1; therefore, we evaluated the newly discovered UCP1-independent thermogenesis pathway. We confirmed that SERCA2b and RYR2, the two key genes involved in this pathway, were upregulated in the WAT. Our data suggest that the upregulation of NPRs, β-1R and β-3R, lipolysis, and SERCA2b and RYR2 may be one of the mechanisms by which RIM promotes beiging and overall the improvement of metabolic homeostasis induced by RIM.

Transcriptional profiling identifies strain-specific effects of caloric restriction and opposite responses in human and mouse white adipose tissue

Caloric restriction (CR) has been extensively studied in rodents as an intervention to improve lifespan and healthspan. However, effects of CR can be strain- and species-specific. This study used publically available microarray data to analyze expression responses to CR in males from 7 mouse strains (C57BL/6J, BALB/c, C3H, 129, CBA, DBA, B6C3F1) and 4 tissues (epididymal white adipose tissue (eWAT), muscle, heart, cortex). In each tissue, the largest number of strain-specific CR responses was identified with respect to the C57BL/6 strain. In heart and cortex, CR responses in C57BL/6 mice were negatively correlated with responses in other strains. Strain-specific CR responses involved genes associated with olfactory receptors (Olfr1184, Olfr910) and insulin/IGF-1 signaling (Igf1, Irs2). In each strain, CR responses in eWAT were negatively correlated with those in human subcutaneous WAT (scWAT). In human scWAT, CR increased expression of genes associated with stem cell maintenance and vascularization. However, orthologous genes linked to these processes were down-regulated in mouse. These results identify strain-specific CR responses limiting generalization across mouse strains. Differential CR responses in mouse versus human WAT may be due to differences in the depots examined and/or the presence of “thrifty genes” in humans that resist adipose breakdown despite caloric deficit.

Histologic analysis and lipid profiling reveal reproductive age-associated changes in peri-ovarian adipose tissue

BACKGROUND

Reproductive aging is a robust phenotype that occurs in all females and is characterized by a significant reduction in gamete quantity and quality, which can have negative consequences on both endocrine function and fertility. Age-associated differences in the oocyte, follicle, and ovary have been well-documented, but how the broader environment changes with age is less well understood. Fat is one of the largest organs in the body, and peri-gonadal adipose tissue surrounds the rodent ovary and comprises a local ovarian environment. The goal of this study was to characterize how peri-ovarian adipose tissue changes with advanced reproductive age.

METHODS

We isolated peri-gonadal adipose tissue from two cohorts of CB6F1 mice: reproductively young (6-12 weeks) and reproductively old (14-17 months). A comparative histological analysis was performed to evaluate adipocyte architecture. We then extracted lipids from the tissue and performed multiple reaction monitoring (MRM)-profiling, a mass spectrometry-based method of metabolite profiling, to compare the lipid profiles of peri-gonadal adipose tissue in these age cohorts.

RESULTS

We found that advanced reproductive age was associated with adipocyte hypertrophy and a corresponding decrease in the number of adipocytes per area. Of the 10 lipid classes examined, triacylglycerols (TAGs) had significantly different profiles between young and old cohorts, despite quantitative analysis revealing a decrease in the total amount of TAGs per weight of peri-gonadal adipose tissue with age.

CONCLUSIONS

These findings pinpoint age-associated physiological changes in peri-gonadal adipose tissue with respect to adipocyte morphology and lipid profiles and lay the foundation for future studies to examine how these alterations may influence both adipocyte and ovarian function.

Neuroendocrine Regulation of Energy Metabolism Involving Different Types of Adipose Tissues

Despite tremendous research efforts to identify regulatory factors that control energy metabolism, the prevalence of obesity has been continuously rising, with nearly 40% of US adults being obese. Interactions between secretory factors from adipose tissues and the nervous system innervating adipose tissues play key roles in maintaining energy metabolism and promoting survival in response to metabolic challenges. It is currently accepted that there are three types of adipose tissues, white (WAT), brown (BAT), and beige (BeAT), all of which play essential roles in maintaining energy homeostasis. WAT mainly stores energy under positive energy balance, while it releases fuels under negative energy balance. Thermogenic BAT and BeAT dissipate energy as heat under cold exposure to maintain body temperature. Adipose tissues require neural and endocrine communication with the brain. A number of WAT adipokines and BAT batokines interact with the neural circuits extending from the brain to cooperatively regulate whole-body lipid metabolism and energy homeostasis. We review neuroanatomical, histological, genetic, and pharmacological studies in neuroendocrine regulation of adipose function, including lipid storage and mobilization of WAT, non-shivering thermogenesis of BAT, and browning of BeAT. Recent whole-tissue imaging and transcriptome analysis of differential gene expression in WAT and BAT yield promising findings to better understand the interaction between secretory factors and neural circuits, which represents a novel opportunity to tackle obesity.

Anti-diabetic properties of different fractions of Korean red ginseng

ETHNOPHARMACOLOGICAL RELEVANCE

Korean red ginseng (KRG) has been traditionally used to treat diabetes. Ginsenosides are considered as the major bioactive components mediating anti-diabetic effects of KRG. However, considering that ginsenosides account for only about 3-4% of ginsengs, other fractions of KRG may also carry potential anti-diabetic effects. There is no study reporting the differentiated effects of ginsenosides (Spn) and non-saponin fractions (NSpn) of KRG on glycemic control.

AIM OF THE STUDY

We investigated the effects of KRG, Spn, and NSpn on the indications of glycemic control and sought to elucidate physiological factors contributing their effects.

MATERIALS AND METHODS

Human T2DM mimicking Nagoya-Shibata-Yasuda (NSY/hos) mice were given KRG, Spn, or NSpn admixed in rodent diet at 200 mg/kg/day for 24 weeks. Glycemic and obesity indications, blood lipid profile, systematic and local oxidative stress markers in metabolically important organs, and systematic inflammatory markers were assessed. Molecular assessments associated with glycemic control in liver and skeletal muscle were further performed.

RESULTS

KRG attenuated deterioration in glucose homeostasis as evidenced by significantly lower fasting blood glucose from 22^nd week and AUC during GTT at the end of the experiment compare to control. Spn enhanced insulin secretion in response to glucose stimulation and reduced protein level of glycogen phosphorylase in liver. On the other hand, NSpn ameliorated oxidative stress and inflammation. Some beneficial effects of Spn and NSpn were reflected in KRG treated mice. KRG also attenuated the accumulation of malondialdehyde in skeletal muscle and, accordingly, enhanced insulin responsiveness compare to control.

CONCLUSION

Anti-diabetic properties of KRG are not solely determined by the contents of ginsenosides but the harmonic functions of its different fractions.

Breast Lipofilling Does Not Pose Evidence of Chronic Inflammation in Rats

BACKGROUND

Laboratory reports on adipose tissue suggest that fat grafting to the breast may pose an oncologic risk. One possible reason for this is the theoretic chronic inflammation due to adipokynes released by grafted white adipose tissue (WAT).

OBJECTIVES

The aim of this study was to analyze inflammatory activity in lipofilled breast through the use of proinflammatory markers.

METHODS

Fifty-four paired-breasts of female rats were divided into 4 groups: control, sham, and breasts grafted with either autologous subcutaneous (SC) WAT or autologous omentum (OM). The WAT was prepared through centrifugation, and the grafting was performed with the use of 0.9-mm blunt-tip cannula. The rats were killed 8 weeks postoperatively, and their breasts were harvested for immunohistochemical staining for CD68-expressing macrophages, gene expression (real-time PCR) for monocyte chemoattractant protein 1 (MCP-1), F4/80, Cox-2, and IL-6.

RESULTS

The weights of the rats that underwent a procedure differed from those of the unmanipulated control group (P < 0.01). The macrophage counts of CD68 differed only between breasts lipofilled with OM and control (P < 0.01). MCP-1, F4/80, and Cox-2 were similarly expressed among the groups (P = 0.422, P = 0.143, and P = 0.209, respectively). The expression of IL-6 differed between breast samples grafted with SC and OM WAT (P = 0.015), but not between samples of control and OM (P = 0.752), and control and SC (P = 0.056).

CONCLUSIONS

No inflammation activity was identified in the microenvironment of lipofilled breasts, indicating that chronic inflammation does not seem to be triggered by the breast lipofilling procedure.

Vitamin D restriction enhances periovarian adipose tissue inflammation in a model of menopause

Background: Menopause and deficiency in vitamin D (VD) are two health problems usually associated with aging women.Objective: We aimed to study inflammation in visceral adipose tissue when bilateral ovariectomy is combined with dietary restriction in VD.Methods: We studied 60 female C57BL/6 mice 3 months of age. Half of the animals had bilateral ovariectomy (Ovx group, n = 30) and half a sham procedure (Control [C] group, n = 30), and half of each Ovx or C group were fed a standard diet containing VD or a diet restricted in VD (D-) for an additional 12 weeks. Therefore, four groups were formed (n = 15 each group): C, C(D-), Ovx, and Ovx(D-). After sacrifice, the periovarian adipose tissue (PAT) was investigated.Results: In PAT, we observed different levels of hypertrophied adipocytes, enhanced proinflammatory cytokines, activation of inflammatory markers, and components of the extracellular signal-regulated kinase. The most affected PAT was seen in the Ovx(D-) group, followed by the Ovx group, the C(D-) group, and the C group (the least altered).Conclusion: The results demonstrate that ovariectomy and dietary restriction of VD are inducers of adverse effects on mouse visceral adipose tissue. When combined, these insults might enhance PAT inflammation.

Fat Grafting into Younger Recipients Improves Volume Retention in an Animal Model

BACKGROUND

Soft-tissue deficits associated with various craniofacial anomalies can be addressed by fat grafting, although outcomes remain unpredictable. Furthermore, consensus does not exist for timing of these procedures. Whereas some advocate approaching soft-tissue reconstruction after the underlying skeletal foundation has been corrected, other studies have suggested that earlier grafting may exploit a younger recipient niche that is more conducive to fat graft survival. As there is a dearth of research investigating effects of recipient age on fat graft volume retention, this study compared the effectiveness of fat grafting in younger versus older animals through a longitudinal, in vivo analysis.

METHODS

Human lipoaspirate from three healthy female donors was grafted subcutaneously over the calvaria of immunocompromised mice. Volume retention over 8 weeks was evaluated using micro-computed tomography at three experimental ages: 3 weeks, 6 months, and 1 year. Histologic examination was performed on explanted grafts to evaluate graft health and vascularity. Recipient-site vascularity was also evaluated by confocal microscopy.

RESULTS

The greatest retention of fat graft volume was noted in the youngest group compared with both older groups (p < 0.05) at 6 and 8 weeks after grafting. Histologic and immunohistochemical analyses revealed that improved retention in younger groups was associated with greater fat graft integrity and more robust vascularization.

CONCLUSION

The authors' study provides evidence that grafting fat into a younger recipient site correlates with improved volume retention over time, suggesting that beginning soft-tissue reconstruction with fat grafting in patients at an earlier age may be preferable to late correction.

Dyslipidemia and the role of adipose tissue in early pregnancy in the BPH/5 mouse model for preeclampsia

The hypertensive pregnancy disorder preeclampsia (PE) is a leading cause of fetal and maternal morbidity/mortality. Obesity increases the risk to develop PE, presumably via the release of inflammatory mediators from the adipose tissue, but the exact etiology remains largely unknown. Using obese PE-like blood pressure high subline 5 (BPH/5) and lean gestational age-matched C57Bl6 mice, we aimed to obtain insight into differential reproductive white adipose tissue (rWAT) gene expression, circulating lipids and inflammation at the maternal-fetal interface during early pregnancy. In addition, we investigated the effect of 7 days 25% calorie restriction (CR) in early pregnancy on gene expression in rWAT and implantation sites. Compared with C57Bl6, female BPH/5 are dyslipidemic before pregnancy and show an amplification of rWAT mass, circulating cholesterol, free fatty acids, and triacylglycerol levels throughout pregnancy. RNA sequencing showed that pregnant BPH/5 mice have elevated gene enrichment in pathways related to inflammation and cholesterol biosynthesis at embryonic day (e) 7.5. Expression of cholesterol-related HMGCS1, MVD, Cyp51a1, and DHCR was validated by quantitative reverse-transcription-polymerase chain reaction. CR during the first 7 days of pregnancy restored the relative mRNA expression of these genes to a level comparable to C57Bl6 pregnant females and reduced the expression of circulating leptin and proinflammatory prostaglandin synthase 2 in both rWAT and implantation sites in BPH/5 mice at e7.5. Our data suggest a possible role for rWAT in the dyslipidemic state and inflammatory uterine milieu that might underlie the pathogenesis of PE. Future studies should further address the physiological functioning of the adipose tissue in relation to PE-related pregnancy outcomes.

Changes in adipose tissue physiology during the first two weeks posthatch in chicks from lines selected for low or high body weight

Chickens from lines selected for low (LWS) or high (HWS) body weight (BW) differ in appetite and adiposity. Mechanisms associated with the predisposition to becoming obese are unclear. The objective of the experiment was to evaluate developmental changes in depot-specific adipose tissue during the first 2 wk posthatch. Subcutaneous (SQ), clavicular (CL), and abdominal (AB) depots were collected at hatch (DOH) and days 4 (D4) and 14 (D14) posthatch for histological and mRNA measurements. LWS chicks had decreased SQ fat mass on a BW basis with reduced adipocyte size from DOH to D4 and increased BW and fat mass with unchanged adipocyte size from D4 to D14. HWS chicks increased in BW from DOH to D14 and increased in fat mass in all three depots with enlarged adipocytes in the AB depot from D4 to D14. Meanwhile, CCAAT/enhancer-binding protein-α, neuropeptide Y, peroxisome proliferator-activated receptor-γ, and acyl-CoA dehydrogenase mRNAs differed among depots between lines at different ages. Plasma nonesterified fatty acids were greater in LWS than HWS at D4 and D14. From DOH to D4, LWS chicks mobilized SQ fat and replenished the reservoir through hyperplasia, whereas HWS chicks were dependent on hyperplasia and hypertrophy to maintain adipocyte size and depot mass. From D4 to D14, adipose tissue catabolism and adipogenesis slowed. Whereas LWS fat depots and adipocyte sizes remained stable, HWS chicks rapidly accumulated fat in CL and AB depots. Chicks predisposed to be anorexic or obese have different fat development patterns during the first 2 wk posthatch.

Deletion of leptin receptors in vagal afferent neurons disrupts estrogen signaling, body weight, food intake and hormonal controls of feeding in female mice

Deletion of the leptin receptor from vagal afferent neurons (VAN) using a conditional deletion (Nav1.8/LepR^fl/fl) results in an obese phenotype with increased food intake and lack of exogenous cholecystokinin (CCK)-induced satiation in male mice. Female mice are partially protected from weight gain and increased food intake in response to ingestion of high-fat (HF) diets. However, whether the lack of leptin signaling in VAN leads to an obese phenotype or disruption of hypothalamic-pituitary-gonadal axis function in female mice is unclear. Here, we tested the hypothesis that leptin signaling in VAN is essential to maintain estrogen signaling and control of food intake, energy expenditure, and adiposity in female mice. Female Nav1.8/LepR^fl/fl mice gained more weight, had increased gonadal fat mass, increased meal number in the dark phase, and increased total food intake compared with wild-type controls. Resting energy expenditure was unaffected. The decrease in food intake produced by intraperitoneal injection of CCK (3 μg/kg body wt) was attenuated in female Nav1.8/LepR^fl/fl mice compared with wild-type controls. Intraperitoneal injection of ghrelin (100 μg/kg body wt) increased food intake in Nav1.8/LepR^fl/fl mice but not in wild-type controls. Ovarian steroidogenesis was suppressed, resulting in decreased plasma estradiol, which was accompanied by decreased expression of estrogen receptor-1 (Esr1) in VAN but not in the hypothalamic arcuate nucleus. These data suggest that the absence of leptin signaling in VAN is accompanied by disruption of estrogen signaling in female mice, leading to an obese phenotype possibly via altered control of feeding behavior.

Targeting White Adipose Tissue with Exercise or Bariatric Surgery as Therapeutic Strategies in Obesity

Adipose tissue is critical to whole-body energy metabolism and has become recognized as a bona fide endocrine organ rather than an inert lipid reservoir. As such, adipose tissue is dynamic in its ability to secrete cytokines, free fatty acids, lipokines, hormones and other factors in response to changes in environmental stimuli such as feeding, fasting and exercise. While excess adipose tissue, as in the case of obesity, is associated with metabolic complications, mass itself is not the only culprit in obesity-driven metabolic abnormalities, highlighting the importance of healthy and metabolically adaptable adipose tissue. In this review, we discuss the fundamental cellular processes of adipose tissue that become perturbed in obesity and the impact of exercise on these processes. While both endurance and resistance exercise can promote positive physiological adaptations in adipose tissue, endurance exercise has a more documented role in remodeling adipocytes, increasing adipokine secretion and fatty acid mobilization and oxidation during post-exercise compared with resistance exercise. Exercise is considered a viable therapeutic strategy for the treatment of obesity to optimize body composition, in particular as an adjuvant therapy to bariatric surgery; however, there is a gap in knowledge of the molecular underpinnings of these exercise-induced adaptations, which could provide more insight and opportunity for precision-based treatment strategies.

High-Fat Diet Alters Immunogenic Properties of Circulating and Adipose Tissue-Associated Myeloid-Derived CD45+DDR2+ Cells

Chronic inflammation is evident in the adipose tissue and periphery of patients with obesity, as well as mouse models of obesity. T cell subsets in obese adipose tissue are skewed towards Th1- and Th17-associated phenotypes and their secreted cytokines contribute to obesity-associated inflammation. Our lab recently identified a novel, myeloid-derived CD45⁺DDR2⁺ cell subset that modulates T cell activity. The current study sought to determine how these myeloid-derived CD45⁺DDR2⁺ cells are altered in the adipose tissue and peripheral blood of preobese mice and how this population modulates T cell activity. C57BL/6 mice were fed with a diet high in milkfat (60%·kcal, HFD) ad libitum until a 20% increase in total body weight was reached, and myeloid-derived CD45⁺DDR2⁺ cells and CD4⁺ T cells in visceral adipose tissue (VAT), mammary gland-associated adipose tissue (MGAT), and peripheral blood (PB) were phenotypically analyzed. Also analyzed was whether mediators from MGAT-primed myeloid-derived CD45⁺DDR2⁺ cells stimulate normal CD4⁺ T cell cytokine production. A higher percentage of myeloid-derived CD45⁺DDR2⁺ cells expressed the activation markers MHC II and CD80 in both VAT and MGAT of preobese mice. CD4⁺ T cells were preferentially skewed towards Th1- and Th17-associated phenotypes in the adipose tissue and periphery of preobese mice. In vitro, MGAT from HFD-fed mice triggered myeloid-derived CD45⁺DDR2⁺ cells to induce CD4⁺ T cell IFN-γ and TNF-α production. Taken together, this study shows that myeloid-derived CD45⁺DDR2⁺ cells express markers of immune activation and suggests that they play an immune modulatory role in the adipose tissue of preobese mice.

Administration of eicosapentaenoic and docosahexaenoic acids may improve the remodeling and browning in subcutaneous white adipose tissue and thermogenic markers in brown adipose tissue in mice

The role of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in browning and thermogenesis has not been fully elucidated. Thus, we meant to evaluate the effect of EPA and DHA, administered alone or combined, with the activation of browning markers in subcutaneous white adipose tissue (sWAT), and thermogenic markers in brown adipose tissue (BAT). C57BL/6 adult male mice received a control diet or a high-fructose diet (HFru) for eight weeks, but after the first three weeks, HFru was divided into new groups: HFru, HFru + EPA, HFru + DHA, and HFru-EPA + DHA. EPA and DHA diminished adipocyte hypertrophy, recovered markers of browning in sWAT and thermogenic factors in the BAT, and improved gene expressions linked with mitochondrial biogenesis and lipid metabolism. Importantly, EPA and DHA administrated alone showed stronger results than the combination of EPA + DHA. The results suggest that EPA and DHA might be useful as adjuvant strategies to treat metabolic-associated disorders.

The Frequencies of Immunosuppressive Cells in Adipose Tissue Differ in Human, Non-human Primate, and Mouse Models

Although the metabolic properties of white adipose tissue have been extensively characterized, the tissue's immune properties are now attracting renewed interest. Early experiments in a mouse model suggested that white adipose tissue contains a high density of regulatory T cells (Tregs), and so it was assumed that all adipose tissue has an immunosuppressive profile—even though the investigation was limited to visceral body fat in relatively old male mice. This observation was also corroborated by high frequencies of other cell subsets with immunoregulatory properties, such as anti-inflammatory M2 macrophages, and regulatory B cells. Many studies have since evidenced the persistence of pathogens (trypanosomes, Mycobacterium tuberculosis, HIV, etc.) in adipose tissue. However, a recent report identified adipose tissue as a reservoir of memory T cells capable of protecting animals upon rechallenge. The immune potential of lean adipose tissue thus remains to be further investigated. Here, we compared the relative proportions of immune cells (and Tregs in particular) in lean adipose tissue collected from humans, a non-human primate (the cynomolgus macaque), and three mouse models. We demonstrated that the proportion of Foxp3+ Tregs in visceral adipose tissue was low in all models other than the C57Bl/6 mouse. These low values were not linked to correspondingly low proportions of effector cells because T lymphocytes (a main target of Treg suppression) were more frequent in cynomolgus macaques than in C57Bl/6 mice and (to a lesser extent) humans. In contrast, the proportions of macrophages and B cells were lower in cynomolgus macaques than in C57Bl/6 mice. We also observed a higher proportion of CD34+CD45- cells (which predominantly correspond to mesenchymal stem cells) in C57Bl/6 mouse and cynomolgus macaques than in humans and both for subcutaneous and visceral adipose tissues. Lastly, a microscopy analysis confirmed predominant proportion of adipocytes within adipose tissue, and highlighted a marked difference in adipocyte size among the three species studied. In conclusion, our study of lean, middle-aged, male individuals showed that the immune compartment of adipose tissue differed markedly in humans vs. mice, and suggesting the presence of a more inflammatory steady-state profile in humans than mice.

Obesity "complements" preeclampsia

Preeclampsia (PE) is a devastating adverse outcome of pregnancy. Characterized by maternal hypertension, PE, when left untreated, can result in death of both mother and baby. The cause of PE remains unknown, and there is no way to predict which women will develop PE during pregnancy. The only known treatment is delivery of both the fetus and placenta; therefore, an abnormal placenta is thought to play a causal role. Women with obesity before pregnancy have an increased chance of developing PE. Increased adiposity results in a heightened state of systemic inflammation that can influence placental development. Adipose tissue is a rich source of proinflammatory cytokines and complement proteins, which have been implicated in the pathogenesis of PE by promoting the expression of antiangiogenic factors in the mother. Because an aggravated inflammatory response, angiogenic imbalance, and abnormal placentation are observed in PE, we hypothesize that maternal obesity and complement proteins derived from adipose tissue play an important role in the development of PE.

3D collagen microfibers stimulate the functionality of preadipocytes and maintain the phenotype of mature adipocytes for long term cultures

Although adipose tissue is one of the most abundant tissues of the human body, its reconstruction remains a competitive challenge. The conventional in vitro two or three-dimensional (2D or 3D) models of mature adipocytes unfortunately lead to their quick dedifferentiation after one week, and complete differentiation of adipose derived stem cells (ADSC) usually requires more than one month. In this context, we developed biomimetic 3D adipose tissues with high density collagen by mixing type I collagen microfibers with primary mouse mature adipocytes or human ADSC in transwells. These 3D-tissues ensured a better long-term maintained phenotype of unilocular mature adipocytes, compared to 2D, with a viability of 96 ± 2% at day 14 and a good perilipin immunostaining, - the protein necessary for stabilizing the fat vesicles. For comparison, in 2D culture, mature adipocytes released their fat until splitting their single adipose vesicle into several ones with significantly 4 times smaller size. Concerning ADSC, the adipogenic genes expression in 3D-tissues was found at least doubled throughout the differentiation (over 8 times higher for GLUT4 at day 21), along with it, almost 4 times larger fat vesicles were observed (10 ± 4 µm at day 14). Perilipin immunostaining and leptin secretion, the satiety protein, attested the significantly doubled better functionality of ADSC in 3D adipose tissues. These obtained long-term maintained phenotype and fast adipogenesis make this model relevant for either cosmetic/pharmaceutical assays or plastic surgery purposes. STATEMENT OF SIGNIFICANCE: Adipose tissue has important roles in our organism, providing energy from its lipids storage and secreting many vital proteins. However, its reconstruction in a functional in vitro adipose tissue is still a challenge. Mature adipocytes directly extracted from surgery liposuctions quickly lose their lipids after a week in vitro and the use of differentiated adipose stem cells is too time-consuming. We developed a new artificial fat tissue using collagen microfibers. These tissues allowed the maintenance of viable big unilocular mature adipocytes up to two weeks and the faster adipogenic differentiation of adipose stem cells. Moreover, the adipose functionality confirmed by perilipin and leptin assessments makes this model suitable for further applications in cosmetic/pharmaceutical drug assays or for tissue reconstruction.

Exercise Training Induces Depot-Specific Adaptations to White and Brown Adipose Tissue

Exercise affects whole-body metabolism through adaptations to various tissues, including adipose tissue (AT). Recent studies investigated exercise-induced adaptations to AT, focusing on inguinal white adipose tissue (WAT), perigonadal WAT, and interscapular brown adipose tissue (iBAT). Although these AT depots play important roles in metabolism, they account for only ∼50% of the AT mass in a mouse. Here, we investigated the effects of 3 weeks of exercise training on all 14 AT depots. Exercise induced depot-specific effects in genes involved in mitochondrial activity, glucose metabolism, and fatty acid uptake and oxidation in each adipose tissue (AT) depot. These data demonstrate that exercise training results in unique responses in each AT depot; identifying the depot-specific adaptations to AT in response to exercise is essential to determine how AT contributes to the overall beneficial effect of exercise.

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This study investigates the effects of exercise on all adipose tissue (AT) depots

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Exercise training induces unique metabolic changes to BAT, scWAT, and vWAT

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Exercise training differentially affects each AT depot within BAT, scWAT, and vWAT

Genetically Inherited Obesity and High-Fat Diet-Induced Obesity Differentially Alter Spermatogenesis in Adult Male Rats

Obesity is a multifactorial disorder with predominantly genetic and/or environmental causes. Our aim was to delineate effects of genetically inherited and high-fat diet-induced obesity on fertility and spermatogenesis using two Wistar rat models: genetically inherited obese (GIO) WNIN/Ob rats and diet-induced obese (DIO) rats, which received a high-fat diet. The terminal body weights were similar in both groups, but there was a significant difference in metabolic and hormone profiles between the groups. Fertility assessment revealed a significant decrease in the litter size due to increased pre- and postimplantation loss in the DIO group, whereas the rats in the GIO group were infertile due to lack of libido. Significantly decreased sperm counts were observed in the GIO group compared with the DIO group. Enumeration of testicular cells on the basis of ploidy and cell type-specific expression markers, to study the effect of obesity on spermatogenesis, demonstrated that the GIO and DIO states affected mitosis: spermatogonia and S-phase population were increased. However, distinctive effects were observed on meiosis and spermiogenesis in both the groups. Differential effects of GIO and DIO on fertility and spermatogenesis could be due to the significant difference in white adipose tissue accumulation between the groups and not due to high body weights. The differential effects of obesity suggest male obesity-induced infertility observed in humans could be a combination of genetic and environmental factors.

Obesity May Accelerate the Aging Process

Lines of evidence from several studies have shown that increases in life expectancy are now accompanied by increased disability rate. The expanded lifespan of the aging population imposes a challenge on the continuous increase of chronic disease. The prevalence of overweight and obesity is increasing at an alarming rate in many parts of the world. Further to increasing the onset of metabolic imbalances, obesity leads to reduced life span and affects cellular and molecular processes in a fashion resembling aging. Nine key hallmarks of the aging process have been proposed. In this review, we will review these hallmarks and discuss pathophysiological changes that occur with obesity, that are similar to or contribute to those that occur during aging. We present and discuss the idea that obesity, in addition to having disease-specific effects, may accelerate the rate of aging affecting all aspects of physiology and thus shortening life span and health span.

Reduced Number of Adipose Lineage and Endothelial Cells in Epididymal fat in Response to Omega-3 PUFA in Mice Fed High-Fat Diet

We found previously that white adipose tissue (WAT) hyperplasia in obese mice was limited by dietary omega-3 polyunsaturated fatty acids (omega-3 PUFA). Here we aimed to characterize the underlying mechanism. C57BL/6N mice were fed a high-fat diet supplemented or not with omega-3 PUFA for one week or eight weeks; mice fed a standard chow diet were also used. In epididymal WAT (eWAT), DNA content was quantified, immunohistochemical analysis was used to reveal the size of adipocytes and macrophage content, and lipidomic analysis and a gene expression screen were performed to assess inflammatory status. The stromal-vascular fraction of eWAT, which contained most of the eWAT cells, except for adipocytes, was characterized using flow cytometry. Omega-3 PUFA supplementation limited the high-fat diet-induced increase in eWAT weight, cell number (DNA content), inflammation, and adipocyte growth. eWAT hyperplasia was compromised due to the limited increase in the number of preadipocytes and a decrease in the number of endothelial cells. The number of leukocytes and macrophages was unaffected, but a shift in macrophage polarization towards a less inflammatory phenotype was observed. Our results document that the counteraction of eWAT hyperplasia by omega-3 PUFA in dietary-obese mice reflects an effect on the number of adipose lineage and endothelial cells.

TNF, but not hyperinsulinemia or hyperglycemia, is a key driver of obesity-induced monocytosis revealing that inflammatory monocytes correlate with insulin in obese male mice

Inflammation contributes to obesity-related hyperinsulinemia and insulin resistance, which often precede type 2 diabetes. Inflammation is one way that obesity can promote insulin resistance. It is not clear if the extent of obesity, hyperinsulinemia, or hyperglycemia, underpins changes in cellular immunity during diet-induced obesity. In particular, the requirement for obesity or directionality in the relationship between insulin resistance and monocyte characteristics is poorly defined. Inflammatory cytokines such as tumor necrosis factor (TNF) can contribute to insulin resistance. It is unclear if TNF alters monocytosis or specific markers of cellular immunity in the context of obesity. We measured bone marrow and blood monocyte characteristics in WT and TNF-/- mice that were fed obesogenic, high fat (HF) diets. We also used hyperglycemic Akita mice and mice implanted with insulin pellets in order to determine if glucose or insulin were sufficient to alter monocyte characteristics. We found that diet-induced obesity in male mice increased the total number of monocytes in blood, but not in bone marrow. Immature, inflammatory (Ly6Chigh ) monocytes decreased within the bone marrow and increased within peripheral blood of HF-fed mice. We found that neither hyperinsulinemia nor hyperglycemia was sufficient to induce the observed changes in circulating monocytes in the absence of diet-induced obesity. In obese HF-fed mice, antibiotic treatment lowered insulin and insulin resistance, but did not alter circulating monocyte characteristics. Fewer Ly6Chigh monocytes were present within the blood of HF-fed TNF-/- mice in comparison to HF-fed wild-type (WT) mice. The prevalence of immature Ly6Chigh monocytes in the blood correlated with serum insulin and insulin resistance irrespective of the magnitude of adipocyte or adipose tissue hypertrophy in obese mice. These data suggest that diet-induced obesity instigates a TNF-dependent increase in circulating inflammatory monocytes, which predicts increased blood insulin and insulin resistance independently from markers of adiposity or adipose tissue expansion.

Involvement of glucocorticoid prereceptor metabolism and signaling in rat visceral adipose tissue lipid metabolism after chronic stress combined with high-fructose diet

Both fructose overconsumption and increased glucocorticoids secondary to chronic stress may contribute to overall dyslipidemia. In this study we specifically assessed the effects and interactions of dietary fructose and chronic stress on lipid metabolism in the visceral adipose tissue (VAT) of male Wistar rats. We analyzed the effects of 9-week 20% high fructose diet and 4-week chronic unpredictable stress, separately and in combination, on VAT histology, glucocorticoid prereceptor metabolism, glucocorticoid receptor subcellular redistribution and expression of major metabolic genes. Blood triglycerides and fatty acid composition were also measured to assess hepatic Δ9 desaturase activity. The results showed that fructose diet increased blood triglycerides and Δ9 desaturase activity. On the other hand, stress led to corticosterone elevation, glucocorticoid receptor activation and decrease in adipocyte size, while phosphoenolpyruvate carboxykinase, adipose tissue triglyceride lipase, FAT/CD36 and sterol regulatory element binding protein-1c (SREBP-1c) were increased, pointing to VAT lipolysis and glyceroneogenesis. The combination of stress and fructose diet was associated with marked stimulation of fatty acid synthase and acetyl-CoA carboxylase mRNA level and with increased 11β-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase protein levels, suggesting a coordinated increase in hexose monophosphate shunt and de novo lipogenesis. It however did not influence the level of peroxisome proliferator-activated receptor-gamma, SREBP-1c and carbohydrate responsive element-binding protein. In conclusion, our results showed that only combination of dietary fructose and stress increase glucocorticoid prereceptor metabolism and stimulates lipogenic enzyme expression suggesting that interaction between stress and fructose may be instrumental in promoting VAT expansion and dysfunction.

Agaricus bisporus supplementation reduces high-fat diet-induced body weight gain and fatty liver development

Obesity is a global epidemic characterized not only by excessive fat deposition but also by important complications such as nonalcoholic liver steatosis. Beneficial antiobesogenic effects have been described for some mushrooms. The current study aimed to demonstrate the protective effect of Agaricus bisporus (AB) supplementation against the metabolic alterations induced by high-fat-diet (HFD) feeding. Eight-week-old C57BL/6J mice were fed for 10 weeks with one of the following diets: (1) control diet (n = 7), (2) HFD (n = 7), (3) HFD supplemented with 5% AB (n = 9), and (4) HFD supplemented with 10% AB (n = 9). A pair-fed group was also included for the 10% AB group (n = 6). The impact of AB supplementation on food intake, body weight gain, and liver and fat pad weights was examined. Biochemical, histological, and molecular parameters were also analyzed. Dietary supplementation with 10% AB reduced the HFD-induced increase in body, epididymal, and mesenteric fat weights (p < 0.01, p < 0.05, and p < 0.05, respectively). Supplementation with AB also reduced liver damage in a dose-dependent manner (p < 0.01 and p < 0.001). This effect was confirmed by histological analysis that showed that liver steatosis was markedly reduced in mice fed with AB. The beneficial properties of 10% AB supplementation appear to be mediated through a decrease in food intake and via stimulation of mesenteric and hepatic free-fatty acid beta-oxidation, along with a decrease in epidydimal and hepatic expression of CD36. In conclusion, supplementation with AB prevents excessive body weight gain and liver steatosis induced by HFD consumption.

MiRNA-seq reveals that miR-124-3p inhibits adipogenic differentiation of the stromal vascular fraction in sheep via targeting C/EBPα

MicroRNAs (miRNAs) are small noncoding 20-25 nt RNA molecules that regulate gene expression by posttranscriptional repression of messenger RNA. There have been few investigations on the profiles and functions of miRNAs in ovine subcutaneous fat; their roles in the metabolism and deposition of subcutaneous fat also remain unclear. In this study, small RNA libraries were constructed for 2 important Chinese local sheep breeds, Small-tailed Han Sheep, and Shanxi Meat Sheep Dam Line, and used for high-throughput sequencing. Differentially expressed miRNAs were identified, revealing the effect of miR-124-3p on adipogenic differentiation by targeting C/EBPα. Our results provide both a comprehensive understanding of miRNA expression patterns in sheep subcutaneous fat and an insight into the specific roles of miRNAs in adipogenesis.

Utilizing Confocal Microscopy to Characterize Human and Mouse Adipose Tissue

Significant advances in our understanding of human obesity, endocrinology, and metabolism have been made possible by murine comparative models, in which anatomically analogous fat depots are utilized; however, current research has questioned how truly analogous these depots are. In this study, we assess the validity of the analogy from the perspective of cellular architecture. Whole tissue mounting, confocal microscopy, and image reconstruction software were used to characterize the three-dimensional structure of the inguinal fat pad in mice, gluteofemoral fat in humans, and subcutaneous adipose tissue of the human abdominal wall. Abdominal and gluteofemoral adipose tissue specimens from 12 human patients and bilateral inguinal fat pads from 12 mice were stained for adipocytes, blood vessels, and a putative marker for adipose-derived multipotent progenitor cells, cluster of differentiation 34 (CD34). Samples were whole-mounted and imaged with laser scanning confocal microscopy. Expectedly, human adipocytes were larger and demonstrated greater size heterogeneity. Mouse fat displayed significantly higher vascular density compared with human fat when normalized to adipocyte count. There was no significant difference in the concentration of CD34-positive (CD34⁺) stromal cells from either species. However, the mean distance between CD34⁺ stromal cells and blood vessels was significantly greater in human fat. Finally, mouse inguinal fat contained larger numbers of brown adipocytes than did human gluteofemoral or human abdominal fat. Overall, the basic architecture of human adipose tissue differs significantly from that of mice. Insofar as human gluteofemoral fat differs from human abdominal adipose tissue, it was closer to mouse inguinal fat, being its comparative developmental analog. These differences likely confer variance in functional properties between the two sources and thus must be considered when designing murine models of human disease.

Adipocyte biology: It is time to upgrade to a new model

Globally, the obesity pandemic is profoundly affecting quality of life and economic productivity, but efforts to address this, especially on a pharmacological level, have generally proven unsuccessful to date, serving as a stark demonstration that our understanding of adipocyte biology and pathophysiology is incomplete. To deliver better insight into adipocyte function and obesity, we need improved adipocyte models with a high degree of fidelity in representing the in vivo state and with a diverse range of experimental applications. Adipocyte cell lines, especially 3T3-L1 cells, have been used extensively over many years, but these are limited in terms of relevance and versatility. In this review, I propose that primary adipose-derived stromal/stem cells (ASCs) present a superior model with which to study adipocyte biology ex vivo. In particular, ASCs afford us the opportunity to study adipocytes from different, functionally distinct, adipose depots and to investigate, by means of in vivo/ex vivo studies, the effects of many different physiological and pathophysiological factors, such as age, body weight, hormonal status, diet and nutraceuticals, as well as disease and pharmacological treatments, on the biology of adipocytes and their precursors. This study will give an overview of the characteristics of ASCs and published studies utilizing ASCs, to highlight the areas where our knowledge is lacking. More comprehensive studies in primary ASCs will contribute to an improved understanding of adipose tissue, in healthy and dysfunctional states, which will enhance our efforts to more successfully manage and treat obesity.

New approaches targeting brown adipose tissue transplantation as a therapy in obesity

Brown adipose tissue (BAT) is raising high expectations as a potential target in the fight against metabolic disorders such as obesity and type 2 diabetes. BAT utilizes fuels such as fatty acids to maintain body temperature by uncoupling mitochondrial electron transport to produce heat instead of ATP. This process is called thermogenesis. BAT was considered to be exclusive to rodents and human neonates. However, in the last decade several studies have demonstrated that BAT is not only present but also active in adult humans and that its activity is reduced in several pathological conditions, such as aging, obesity, and diabetes. Thus, tremendous efforts are being made by the scientific community to enhance either BAT mass or activity. Several activators of thermogenesis have been described, such as natriuretic peptides, bone morphogenic proteins, or fibroblast growth factor 21. Furthermore, recent studies have tested a therapeutic approach to directly increase BAT mass by the implantation of either adipocytes or fat tissue. This approach might have an important future in regenerative medicine and in the fight against metabolic disorders. Here, we review the emerging field of BAT transplantation including the various sources of mesenchymal stem cell isolation in rodents and humans and the described metabolic outcomes of adipocyte cell transplantation and BAT transplantation in obesity.

Denervation as a tool for testing sympathetic control of white adipose tissue

This review summarizes the evidence derived from studies utilizing denervation procedures to demonstrate sympathetic control of white adipose tissue metabolism and body fat mass. A majority of the work demonstrating neural control of white fat was performed in the Bartness laboratory with Siberian hamsters as the predominant experimental model. These animals experience dramatic changes in body fat mass in response to changes in photoperiod, however, the mechanisms identified in hamsters have been reproduced or further elucidated by experiments with other animal models. Evidence for the role of sympathetic innervation contributing to the control of white adipocyte lipolysis and preadipocyte proliferation is summarized. In addition, evidence from denervation experiments for neural communication between different white fat depots as well as for a feedback control loop between sensory afferents from individual fat depots and sympathetic efferents to the same or distant white fat depots is discussed.

Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis

BACKGROUND

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring.

RESULTS

The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs).

CONCLUSIONS

We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

Standardized Kaempferia parviflora Wall. ex Baker (Zingiberaceae) Extract Inhibits Fat Accumulation and Muscle Atrophy in ob/ob Mice

Obesity, a metabolic disorder caused by an imbalance between energy intake and energy expenditure, is accompanied with fat accumulation and skeletal muscle atrophy. Kaempferia parviflora Wall. ex Baker, also called black ginger, is known to increase physical fitness performance and improve energy metabolism. In this study, we investigated whether Kaempferia parviflora extract (KPE) alleviates both obesity and muscle atrophy using ob/ob mice. Wild-type C57BL/6J and ob/ob mice were provided with a normal diet ad libitum, and ob/ob mice were orally given KPE at a dose of 100 mg/kg/day or 200 mg/kg/day for eight weeks. KPE significantly decreased body weight, fat volume, and fat weight without affecting appetite. It inhibited the expression of adipogenic transcription factors and lipogenic enzymes by upregulating AMP-activated protein kinase (AMPK) in epididymal fat. In contrast, it markedly increased the muscle fiber size, muscle volume, and muscle mass, resulting in the enhancement of muscle function, such as exercise endurance and grip strength. On the molecular level, it activated the phosphatidylinositol 3 kinase (PI3K)/Akt pathway, a key regulator in protein synthesis in skeletal muscle. KPE could be a promising material to alleviate obesity by inhibiting adipogenesis, lipogenesis, and muscle atrophy.