Adipose tissue and its role in organ crosstalk

Carnosic Acid (CA) Induces a Brown Fat-like Phenotype, Increases Mitochondrial Biogenesis, and Activates AMPK in 3T3-L1 Adipocytes

Adipose tissue plays a crucial role in regulating metabolic homeostasis, and its dysfunction in obesity leads to insulin resistance and type 2 diabetes (T2D). White adipose tissue (WAT) primarily stores energy as lipids, while brown adipose tissue (BAT) regulates thermogenesis by dissipating energy as heat. The process of browning involves the transdifferentiation of WAT into brown-like or beige adipocytes, which exhibit a similar phenotype as BAT. The browning of WAT is an attractive approach against obesity and T2D, and the activation of the energy sensor AMP-activated protein kinase (AMPK) has been shown to play a role in browning. Carnosic acid (CA), a polyphenolic diterpene, found in many plants including rosemary, is reported to possess potent antioxidant, anti-inflammatory, and anti-hyperglycemic properties. The limited evidence available indicates that CA activates AMPK and may have anti-obesity and antidiabetic potential; however, the effects in adipocyte browning remain largely unexplored. This study aimed to examine the effects of CA on the markers of adipocyte browning. The treatment of 3T3L1 adipocytes with CA activated AMPK, reduced lipid accumulation, and increased the expression of browning protein markers (UCP-1, PGC-1α, PRDM16, and TFAM) and mitochondrial biogenesis. The use of compound C, an AMPK inhibitor, significantly attenuated the effects of CA, indicating AMPK involvement. These studies demonstrate that CA can activate AMPK and stimulate the browning of white adipocytes. Future animal and human studies are required to examine the effects of CA in vivo.

The role of mesenchymal stem cells in early programming of adipose tissue in the offspring of women with obesity

Maternal obesity is a well-known risk factor for developing premature obesity, metabolic syndrome, cardiovascular disease and type 2 diabetes in the progeny. The development of white adipose tissue is a dynamic process that starts during prenatal life: fat depots laid down in utero are associated with the proportion of fat in children later on. How early this programming takes place is still unknown. However, recent evidence shows that mesenchymal stem cells (MSC), the embryonic adipocyte precursor cells, show signatures of the early setting of an adipogenic committed phenotype when exposed to maternal obesity. This review aims to present current findings on the cellular adaptations of MSCs from the offspring of women with obesity and how the metabolic environment of MSCs could affect the early commitment towards adipocytes. In conclusion, maternal obesity can induce early programming of fetal adipose tissue by conditioning MSCs. These cells have higher expression of adipogenic markers, altered insulin signalling and mitochondrial performance, compared to MSCs of neonates from lean pregnancies. Fetal MSCs imprinting by maternal obesity could help explain the increased risk of childhood obesity and development of further noncommunicable diseases.

The role of novel adipokines and adipose-derived extracellular vesicles (ADEVs): Connections and interactions in liver diseases

Adipose tissues (AT) are an important endocrine organ that secretes various functional adipokines, peptides, non-coding RNAs, and acts on AT themselves or other distant tissues or organs through autocrine, paracrine, or endocrine manners. An accumulating body of evidence has suggested that many adipokines play an important role in liver metabolism. Besides the traditional adipokines such as adiponectin and leptin, many novel adipokines have recently been identified to have regulatory effects on the liver. Additionally, AT can produce extracellular vesicles (EVs) that act on peripheral tissues. However, under pathological conditions, such as obesity and diabetes, dysregulation of adipokines is associated with functional changes in AT, which may cause liver diseases. In this review, we focus on the newly discovered adipokines and EVs secreted by AT and highlight their actions on the liver under the context of obesity, nonalcoholic fatty liver diseases (NAFLD), and some other liver diseases. Clarifying the action of adipokines and adipose tissue-derived EVs on the liver would help to identify novel therapeutic targets or biomarkers for metabolic diseases.

The effect of heat stress on performance, fertility, and adipokines involved in regulating systemic immune response during lipolysis of early lactating dairy cows

The aim of this study was to assess the potential effect of heat stress on dairy cow productivity, fertility, and biochemical blood indices during the early lactation stage in a temperate climate. Additionally, the study aimed to determine the role of leptin and adiponectin in regulating the immune response accompanying lipolysis after calving in dairy cows. The study included 100 clinically healthy Polish Holstein-Friesian dairy cows selected based on parity and 305 d of milk yield from 5 commercial farms with similar herd management and housing systems. Prospective cohort data were recorded from calving day until 150 d in milk, and microclimate loggers installed inside the barns were used to record temperature and relative humidity data to calculate daily temperature-humidity index (THI) on the calving day, through +7, +14, and +21 d during early lactation. Additionally, monthly productive performance parameters such as milk yield, chemical composition, fatty acids composition, and fertility indices were analyzed. Results showed that the THI from calving day through +7, +14, and +21 d during early lactation was negatively associated with fertility parameters such as delayed first estrus postpartum and an elongated calving interval, respectively, by 29, 27, 25, and 16 d. Furthermore, an increase in THI value during early lactation was associated with an elongated artificially inseminated service period, days open, and intercalving period. Increasing THI from calving day (0 d) through +7, +14, and up to +21 d during early lactation was also linked to decreased milk yield by 3.20, 4.10, 5.60, and 5.60 kg, respectively. The study also found that heat stress during early lactation was associated with a lower body condition score in dairy cows and higher concentrations of leptin, nonesterified fatty acids, and β-hydroxybutyrate, accompanied by a drastic reduction in adipose tissue-secreted adiponectin levels after calving. Additionally, heat stress-induced lipolysis in adipose tissue caused an inflammatory response that increased biochemical blood indices associated with immune responses such as cytokines, acute phase proteins, and heat shock protein. These findings suggest that exposing dairy cows to heat stress during early lactation can negatively affect their productive performance, fertility, and biochemical blood indices in subsequent lactations. Thus, farm management changes should be implemented during early lactation to mitigate the negative consequences of heat stress occurrence.

Chondroitin Sulfate-Derived Micelles for Adipose Tissue-Targeted Delivery of Celastrol and Phenformin to Enhance Obesity Treatment

Adipose tissue macrophages (ATMs) are crucial in maintaining a low-grade inflammatory microenvironment in adipose tissues (ATs). Modulating ATM polarization to attenuate inflammation represents a potential strategy for treating obesity with insulin resistance. This study develops a combination therapy of celastrol (CLT) and phenformin (PHE) using chondroitin sulfate-derived micelles. Specifically, CLT-loaded 4-aminophenylboronic acid pinacol ester-modified chondroitin sulfate micelle (CS-PBE/CLT) and chondroitin sulfate-phenformin conjugate micelles (CS-PHE) were synthesized, which were shown to actively target ATs through CD44-mediated pathways. Furthermore, the dual micellar systems significantly reduced inflammation and lipid accumulation via protein quantification and Oil Red O staining. In preliminary in vivo studies, we performed H&E staining, immunohistochemical staining, insulin tolerance test, and glucose tolerance test, and the results showed that the combination therapy using CS-PBE/CLT and CS-PHE micelles significantly reduced the average body weight, white adipose tissue mass, and liver mass of high-fat diet-fed mice while improving their systemic glucose homeostasis. Overall, this combination therapy presents a promising alternative to current treatment options for diet-induced obesity.

Cross-sectional imaging: current status and future potential in adult celiac disease

Celiac disease (CD), triggered by exposure to gluten in genetically susceptible individuals, is an immune-mediated small bowel disease affecting about 1% of the population worldwide. But the prevalence of CD varies with age, sex, and location. A strict gluten-free diet remains the primary treatment for CD, currently. Most of patients with CD respond well to gluten-free diet with good prognosis, while some patients fail to get symptomatic relief or histological remission (e.g., nonresponsive or refractory CD). Because of heterogeneous clinical appearance, the diagnosis of CD is difficult. Moreover, malignant complications and poor outcomes accompanied with refractory CD present great challenges in disease management. Over the past three decades, cross-sectional imaging techniques (computed tomography [CT] and magnetic resonance imaging [MRI]) play an important role in small bowel inflammatory and neoplastic diseases. Compared with endoscopic techniques, cross-sectional imaging permits clearly presentation of both intraluminal and extraluminal abnormalities. It provides vascular and functional information, thus improving the possibility as diagnostic and follow-up tool. The value of cross-sectional imaging for patients with suspected or confirmed CD has been gradually demonstrated. Studies revealed that certain features suggested by cross-sectional imaging could help to establish the early diagnosis of CD. Besides, the potential contributions of cross-sectional imaging may lie in the evaluation of disease activity and severity, which helps guiding management strategies. The purpose of this review is to provide current overviews and future directions of cross-sectional imaging in adult CD, thus facilitating the understanding and application in clinical practice. CLINICAL RELEVANCE STATEMENT: In this review, we systematically summarized the existing knowledge of cross-sectional imaging in adult CD and analyzed their possible roles in clinical practice, including disease diagnosis, complication identification, treatment evaluation, and prognostic prediction. KEY POINTS: • Regarding a condition described as "celiac iceberg", celiac disease remains underdiagnosed and undertreated. • Cross-sectional imaging is helpful in clinical management of celiac disease, including disease diagnosis, complication identification, treatment evaluation, and prognostic prediction. • Cross-sectional imaging should be considered as the valuable examination in patients suspected from celiac disease.

Are MTV and TLG Accurate for Quantifying the Intensity of Brown Adipose Tissue Activation?

Recent research has suggested that one novel mechanism of action for anti-obesity medications is to stimulate the activation of brown adipose tissue (BAT). 18FDG PET/CT remains the gold standard for defining and quantifying BAT. SUVmax is the most often used quantification tool in clinical practice. However, this parameter does not reflect the entire BAT volume. As a potential method for precisely evaluating BAT, we have utilised metabolic tumour volume (MTV) and total lesion glycolysis (TLG) to answer the question: Are MTV and TLG accurate in quantifying the intensity of BAT activation? After analysing the total number of oncological 18F-FDG PET/CT scans between 2021-2023, we selected patients with active BAT. Based on the BAT SUVmax, the patients were divided into BAT-moderate activation (MA) vs. BAT-high activation (HA). Furthermore, we statistically analysed the accuracy of TLG and MTV in assessing BAT activation intensity. The results showed that both parameters increased their predictive value regarding BAT activation, and presented a significantly high sensitivity and specificity for the correct classification of BAT activation intensity. To conclude, these parameters could be important indicators with increased accuracy for classifying BAT expression, and could bring additional information about the volume of BAT to complement the limitations of the SUVmax.

Sex and Gender Differences on the Impact of Metabolism-Disrupting Chemicals on Obesity: A Systematic Review

Obesity represents an important public health concern, being one of the leading causes of death worldwide. It is a multifactorial disease with many underlying intertwined causes, including genetic, environmental and behavioral factors. Notably, metabolism-disrupting chemicals (MDCs) can alter the set point control of metabolism, affecting the development and function of the adipose tissue. Epidemiological studies have reported associations between human exposure to MDCs and several altered metabolic endpoints. It is also noteworthy that sex and gender represent important risk factors in the development of obesity. Different sex-related biological and physiological characteristics influence individual susceptibility, whereas gender represents a critical component in determining the different exposure scenarios. Although some advancements in the treatment of obesity have been achieved in preclinical and clinical studies, the obesity pandemic continues to increase worldwide. The present study performed a systematic review of recent studies considering the effects of MDCs on obesity, with a specific focus on sex- and gender-related responses. This review highlighted that MDCs could differently affect men and women at different stages of life even though the number of studies evaluating the association between obesity and MDC exposure in relation to sex and gender is still limited. This evidence should urge researchers to carry out studies considering sex and gender differences. This is essential for developing sex-/gender-tailored prevention strategies to improve public health policies and reduce exposure.

Molecular and Metabolic Analysis of Arsenic-Exposed Humanized AS3MT Mice

BACKGROUND

Chronic exposure to inorganic arsenic (iAs) has been associated with type 2 diabetes (T2D). However, potential sex divergence and the underlying mechanisms remain understudied. iAs is not metabolized uniformly across species, which is a limitation of typical exposure studies in rodent models. The development of a new "humanized" mouse model overcomes this limitation. In this study, we leveraged this model to study sex differences in the context of iAs exposure.

OBJECTIVES

The aim of this study was to determine if males and females exhibit different liver and adipose molecular profiles and metabolic phenotypes in the context of iAs exposure.

METHODS

Our study was performed on wild-type (WT) 129S6/SvEvTac and humanized arsenic + 3 methyl transferase (human AS3MT) 129S6/SvEvTac mice treated with 400   ppb of iAs via drinking water ad libitum. After 1 month, mice were sacrificed and the liver and gonadal adipose depots were harvested for iAs quantification and sequencing-based microRNA and gene expression analysis. Serum blood was collected for fasting blood glucose, fasting plasma insulin, and homeostatic model assessment for insulin resistance (HOMA-IR).

RESULTS

We detected sex divergence in liver and adipose markers of diabetes (e.g., miR-34a, insulin signaling pathways, fasting blood glucose, fasting plasma insulin, and HOMA-IR) only in humanized (not WT) mice. In humanized female mice, numerous genes that promote insulin sensitivity and glucose tolerance in both the liver and adipose are elevated compared to humanized male mice. We also identified Klf11 as a putative master regulator of the sex divergence in gene expression in humanized mice.

DISCUSSION

Our study underscored the importance of future studies leveraging the humanized mouse model to study iAs-associated metabolic disease. The findings suggested that humanized males are at increased risk for metabolic dysfunction relative to humanized females in the context of iAs exposure. Future investigations should focus on the detailed mechanisms that underlie the sex divergence. https://doi.org/10.1289/EHP12785.

BNT162b2 Booster Dose Elicits a Robust Antibody Response in Subjects with Abdominal Obesity and Previous SARS-CoV-2 Infection

Little is known about the long-term durability of the induced immune response in subjects with obesity, particularly in those with an abdominal distribution of adipose tissue. We evaluated SARS-CoV-2-specific antibody responses after BNT162b2 vaccine booster dose, comparing individuals with and without abdominal obesity (AO), discerning between individuals previously infected or not. IgG-TrimericS were measured in 511 subjects at baseline, on the 21st day after vaccine dose 1, and at 1, 3, 6, and 9 months from dose 2, and at 1 and 3 months following the booster dose. To detect SARS-CoV-2 infection, nucleocapsid antibodies were measured at baseline and at the end of the study. Multivariable linear regression evaluated the three-month difference in the absolute variation in IgG-TrimericS levels from booster dose, showing AO and SARS-CoV-2 infection status interactions (p = 0.016). Regardless of possible confounding factors and IgG-TrimericS levels at the booster dose, AO is associated with a higher absolute change in IgG-TrimericS in prior infected individuals (p = 0.0125). In the same regression model, no interaction is highlighted using BMI (p = 0.418). The robust response in the development of antibodies after booster dose, observed in people with AO and previous infection, may support the recommendations to administer a booster dose in this population group.

Identification of a Novel Long Non-Coding RNA G8110 That Modulates Porcine Adipogenic Differentiation and Inflammatory Responses

Long non-coding RNAs (lncRNAs) have been extensively studied, and their crucial roles in adipogenesis, lipid metabolism, and gene expression have been revealed. However, the exact regulatory or other mechanisms by which lncRNAs influence the functioning of mesenteric adipose tissue (MAT) remain largely unknown. In this paper, we report the identification of a new lncRNA, named G8110, from the MAT of Bama pigs. The coordinated expression levels of lncRNA G8110 and NFE2L1 were significantly decreased in the MAT of obese Bama pigs compared with those in the MAT of lean pigs. Using a bone mesenchymal stem cell adipogenic differentiation model, we found that lncRNA G8110 played a role in adipocyte differentiation by positively regulating NFE2L1. We also found that lncRNA G8110 inhibited the formation of intracellular lipid synthesis, promoted lipid metabolism, and inhibited the expression of inflammatory cytokines. Our findings regarding lipid synthesis may further promote the role of lncRNAs in driving adipose tissue remodeling and maintaining metabolic health.

Creeping Fat in the Pathogenesis of Crohn's Disease: An Orchestrator or a Silent Bystander?

Although the phenomenon of hypertrophied adipose tissue surrounding inflamed bowel segments in Crohn's disease has been described since 1932, the mechanisms mediating the creeping fat formation and its role in the pathogenesis of the disease have not been fully unraveled. Recent advances demonstrating the multiple actions of adipose tissue beyond energy storage have brought creeping fat to the forefront of scientific research. In Crohn's disease, dysbiosis and transmural injury compromise the integrity of the intestinal barrier, resulting in an excessive influx of intraluminal microbiota and xenobiotics. The gut and peri-intestinal fat are in close anatomic relationship, implying a direct reciprocal immunologic relationship, whereas adipocytes are equipped with an arsenal of innate immunity sensors that respond to invading stimuli. As a result, adipocytes and their progenitor cells undergo profound immunophenotypic changes, leading to adipose tissue remodeling and eventual formation of creeping fat. Indeed, creeping fat is an immunologically active organ that synthesizes various pro- and anti-inflammatory cytokines, profibrotic mediators, and adipokines that serve as paracrine/autocrine signals and regulate immune responses. Therefore, creeping fat appears to be involved in inflammatory signaling, which explains why it has been associated with a higher severity or complicated phenotype of Crohn's disease. Interestingly, there is growing evidence for an alternative immunomodulatory function of creeping fat as a second barrier that prevents an abnormal systemic inflammatory response at the expense of an increasingly proliferating profibrotic environment. Further studies are needed to clarify how this modified adipose tissue exerts its antithetic effect during the course of Crohn's disease.

Inhibiting Phosphatidylcholine Remodeling in Adipose Tissue Increases Insulin Sensitivity

Cell membrane phosphatidylcholine (PC) composition is regulated by lysophosphatidylcholine acyltransferase (LPCAT); changes in membrane PC saturation are implicated in metabolic disorders. Here, we identified LPCAT3 as the major isoform of LPCAT in adipose tissue and created adipocyte-specific Lpcat3-knockout mice to study adipose tissue lipid metabolism. Transcriptome sequencing and plasma adipokine profiling were used to investigate how LPCAT3 regulates adipose tissue insulin signaling. LPCAT3 deficiency reduced polyunsaturated PCs in adipocyte plasma membranes, increasing insulin sensitivity. LPCAT3 deficiency influenced membrane lipid rafts, which activated insulin receptors and AKT in adipose tissue, and attenuated diet-induced insulin resistance. Conversely, higher LPCAT3 activity in adipose tissue from ob/ob, db/db, and high-fat diet-fed mice reduced insulin signaling. Adding polyunsaturated PCs to mature human or mouse adipocytes in vitro worsened insulin signaling. We suggest that targeting LPCAT3 in adipose tissue to manipulate membrane phospholipid saturation is a new strategy to treat insulin resistance.

ARTICLE HIGHLIGHTS

An Evolutionary Model for the Ancient Origins of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrinopathy of reproductive-aged women, characterized by hyperandrogenism, oligo-anovulation and insulin resistance and closely linked with preferential abdominal fat accumulation. As an ancestral primate trait, PCOS was likely further selected in humans when scarcity of food in hunter-gatherers of the late Pleistocene additionally programmed for enhanced fat storage to meet the metabolic demands of reproduction in later life. As an evolutionary model for PCOS, healthy normal-weight women with hyperandrogenic PCOS have subcutaneous (SC) abdominal adipose stem cells that favor fat storage through exaggerated lipid accumulation during development to adipocytes in vitro. In turn, fat storage is counterbalanced by reduced insulin sensitivity and preferential accumulation of highly lipolytic intra-abdominal fat in vivo. This metabolic adaptation in PCOS balances energy storage with glucose availability and fatty acid oxidation for optimal energy use during reproduction; its accompanying oligo-anovulation allowed PCOS women from antiquity sufficient time and strength for childrearing of fewer offspring with a greater likelihood of childhood survival. Heritable PCOS characteristics are affected by today's contemporary environment through epigenetic events that predispose women to lipotoxicity, with excess weight gain and pregnancy complications, calling for an emphasis on preventive healthcare to optimize the long-term, endocrine-metabolic health of PCOS women in today's obesogenic environment.

β-Aminoisobutyric Acid Relates to Favorable Glucose Metabolism through Adiponectin in Adults with Obesity Independent of Prediabetes

β-Aminoisobutyric acid (BAIBA) is secreted by skeletal muscle and promotes insulin sensitivity, fat oxidation, and anti-inflammation. While BAIBA is purportedly lower in individuals with obesity, no work has examined if prediabetes (PD) differentially impacts BAIBA concentrations in people with obesity. Methods. Adults were classified as normal glucose tolerant (NGT; n = 22 (20F); 48.0 ± 2.4 yrs; 36.9 ± 1.2 kg/m2) or PD (n = 23 (18F); 54.2 ± 1.6 yrs; 38.4 ± 1.2 kg/m2) based on ADA criteria. A 180-minute 75 g OGTT was used to estimate fasting (HOMA-IR (liver)) and postprandial (Matsuda index (muscle)) insulin sensitivity as well as β-cell function (disposition index (DI), glucose-stimulated insulin secretion adjusted for insulin sensitivity). Body composition and fasting measures of BAIBA, fat oxidation (indirect calorimetry), and adipokines were determined. Results. NGT and PD had similar BAIBA concentrations (1.4 ± 0.1 vs. 1.2 ± 0.1 μM, P = 0.23) and fat oxidation (P = 0.31), despite NGT having lower fasting (92.2 ± 1.2 vs. 104.1 ± 3.2 mg/dL, P = 0.002) and tAUC180min glucose (P < 0.001) compared to PD. Moreover, NGT had higher postprandial insulin sensitivity (P = 0.01) and higher total phase DIliver (P = 0.003) and DImuscle (P = 0.001). Increased BAIBA was associated with adiponectin (r = 0.37, P = 0.02), adiponectin/leptin ratio (r = 0.39, P = 0.01), and lower glucose and insulin at 180 minutes (r = -0.31, P = 0.03 and r = -0.39, P = 0.03, respectively). Adiponectin also correlated with lower glucose at 180 minutes (r = -0.45, P = 0.005), and mediation analysis showed that BAIBA was no longer a significant predictor of glucose at 180 minutes after controlling for adiponectin (P = 0.08). Conclusion. While BAIBA did not differ between NGT and PD, higher BAIBA is related to favorable glucose metabolism, possibly through an adiponectin-related mechanism. Additional work is required to understand how exercise and/or diet impact BAIBA in relation to type 2 diabetes risk.

Creeping Fat in Crohn's Disease-Surgical, Histological, and Radiological Approaches

During the course of Crohn's disease, the response of mesenteric adipose tissue to the production of inflammatory mediators and bacterial invasion through the intestinal mucosa results in the formation of creeping fat. Creeping fat describes the arresting finger-like projections that surround the inflamed bowel. In this review, the microscopic and macroscopic features of creeping fat and histological evidence for the importance of this tissue are discussed. Moreover, the most recent insights into the radiological assessment of creeping fat in patients with Crohn's disease are reported. Advances in imaging techniques have revolutionized the possibility of visualization and quantification of adipose tissue depots with excellent accuracy. Visceral fat has been significantly correlated with various Crohn's-disease-related outcomes. Despite the difficulties in distinguishing physiologic perienteric fat from creeping fat, the growing interest in fat-wrapping in Crohn's disease has rejuvenated radiologic research. With regard to the noninvasive fat-wrapping assessment, a novel CT enterography-based mesenteric creeping fat index has been developed for the mitigation of the confounding effect of normal retroperitoneal and perienteric adipose tissue. Research on machine learning algorithms and computational radiomics in conjunction with mechanistic studies may be the key for the elucidation of the complex role of creeping fat in Crohn's disease.

The relationship between hormonal levels and hematological parameters in cystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is characterized by the abnormal production of ovarian androgens resulting in elevated levels of male sex hormones in women. This condition is often marked by the development of a group of small cysts, fluid-filled sacs (cysts) in the ovaries. This study aimed to analyze serum levels of prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and specific hematological parameters in women with PCOS. In total, 70 women were enrolled, of which 50 were diagnosed with PCOS at an obstetrics institution in Karbala from February and May 2022, and 20 were excluded. Participant selection was based on the Rotterdam 2003 criteria, and we excluded postmenopausal women, those with hyperprolactinemia, and those with overt thyroid dysfunction. The control group included 20 fertile women with normal hormone levels, regular menstrual cycles, and no signs of hyperandrogenism, as verified by ultrasonography. Ages 15 to 46 were similar with regard to the frequency of illness, with those under 36 having a higher incidence. Data were collected via questionnaires, hormone level assessments, and complete blood count (CBC) tests. There was a significant increase in hormone levels (LH, FSH, prolactin, TSH) and CBC values (WBC, Hb, and Plt) in the PCOS group compared to the control group. We observed that women between 26 and 35 were more susceptible to PCOS. Furthermore, women who were overweight demonstrated a higher susceptibility to the syndrome.

Remodeling of white adipose tissue microenvironment against obesity by phytochemicals

Obesity is a kind of chronic disease due to a long-term imbalance between energy intake and expenditure. In recent years, the number of obese people around the world has soared, and obesity problem should not be underestimated. Obesity is characterized by changes in the adipose microenvironment, mainly manifested as hypertrophy, chronic inflammatory status, hypoxia, and fibrosis, thus contributing to the pathological changes of other tissues. A plethora of phytochemicals have been found to improve adipose microenvironment, thus prevent and resist obesity, providing a new research direction for the treatment of obesity and related diseases. This paper discusses remodeling of the adipose tissue microenvironment as a therapeutic avenue and reviews the progress of phytochemicals in fighting obesity by improving the adipose microenvironment.

Update on the Role of Glucocorticoid Signaling in Osteoblasts and Bone Marrow Adipocytes During Aging

PURPOSE OF REVIEW

Bone marrow adipose tissue (BMAT) in the skeleton likely plays a variety of physiological and pathophysiological roles that are not yet fully understood. In elucidating the complex relationship between bone and BMAT, glucocorticoids (GCs) are positioned to play a key role, as they have been implicated in the differentiation of bone marrow mesenchymal stem cells (BMSCs) between osteogenic and adipogenic lineages. The purpose of this review is to illuminate aspects of both endogenous and exogenous GC signaling, including the influence of GC receptors, in mechanisms of bone aging including relationships to BMAT.

RECENT FINDINGS

Harmful effects of GCs on bone mass involve several cellular pathways and events that can include BMSC differentiation bias toward adipogenesis and the influence of mature BMAT on bone remodeling through crosstalk. Interestingly, BMAT involvement remains poorly explored in GC-induced osteoporosis and warrants further investigation. This review provides an update on the current understanding of the role of glucocorticoids in the biology of osteoblasts and bone marrow adipocytes (BMAds).

Arnica montana L. extract containing 6-O-methacryloylhelenalin and 6-O-isobutyrylhelenalin accelerates growth and differentiation of human subcutaneous preadipocytes and leads volumizing of skin

OBJECTIVE

An important factor in the aging of the face is a reduction in the volume of adipose tissue. This reduction in adipose tissue contributes to decreased skin elasticity, which is also part of the aging process. Overall, these lead to wrinkle formation. Fat injection is a common means of addressing this issue and is used to reduce the effects of aging on the face and to increase the fullness of the lips and breasts. However, fat injection is an invasive surgical procedure. This study aimed to discover novel cosmetic ingredients that increase the volume of subcutaneous (pre)adipocytes to create the appearance of more youthful skin.

METHODS

We focused on the number of subcutaneous preadipocytes and the accumulation of lipid droplets. To discover natural ingredients that increase both of these, extracts of 380 natural products were prepared and screened for their effects on both growth and differentiation (i.e., lipid droplet accumulation) of human subcutaneous preadipocytes. One extract was found to have the desired effects, and this was further studied to determine the active compounds. We then evaluated its efficacy in a human clinical study.

RESULTS

We found that Arnica montana L. flower extract (AFE) accelerates both the growth and the differentiation of human subcutaneous preadipocytes. AFE was found to significantly increase the volume of adipocyte spheroids. The active compounds 6-O-methacryloylhelenalin and 6-O-isobutyrylhelenalin were found to be responsible for the effects of AFE on preadipocytes. In a human clinical study, gels containing 1% AFE successfully enhanced the volume of the lips and face with reduction of wrinkles with no adverse reactions.

CONCLUSION

This is the first report to demonstrate that AFE and the included compounds, 6-O-methacryloylhelenalin and 6-O-isobutyrylhelenalin, act on preadipocytes. AFE would be ideal for use in products that plump the face to reduce wrinkles and create a more youthful appearance.

Two-sided roles of adipose tissue: Rethinking the obesity paradox in various human diseases from a new perspective

Overweight and obesity, as a result of excess fat accumulation, have become a worldwide public health issue. Recent studies have shown that obesity is closely related to many human diseases, such as cancer, cardiovascular diseases, and type 2 diabetes mellitus, in which adipose tissue plays a dual role. In addition to thermal and mechanical insulation and a critical role in energy storage and heat production, adipose tissue is also a highly plastic endocrine and signaling organ that secretes multiple bioactive molecules for inter-organ crosstalk. The phenotypic and biological changes of adipose tissue under pathological conditions, especially in obesity, increase the challenge of deciphering the positive or negative effects of adipose tissue in disease. Despite numerous studies on obesity and adipose tissue, the ambiguous role of adipose tissue on specific organs or tissues in different diseases is not fully understood, and the definite mechanisms remain obscure. In this review, we first summarize the basic biological characteristics of adipose tissue in the physiological state and the abnormal remodeling of adipose tissue during obesity. We then discuss the complex and disparate effects of obesity on various human diseases, with a particular focus on the dual roles and underlying mechanisms of adipose tissue, a quintessential player in obesity, in this process. More importantly, rethinking the causes of the "obesity paradox" phenomenon in diseases from the perspective of adipose homeostasis and dysfunction provides a novel strategy for disease treatment by intervening in fat function.

Abnormal lipid metabolism in cancer-associated cachexia and potential therapy strategy

Cancer-associated cachexia (CAC) is a major characteristic of advanced cancer, associates with almost all types of cancer. Recent studies have found that lipopenia is an important feature of CAC, and it even occurs earlier than sarcopenia. Different types of adipose tissue are all important in the process of CAC. In CAC patients, the catabolism of white adipose tissue (WAT) is increased, leading to an increase in circulating free fatty acids (FFAs), resulting in " lipotoxic". At the same time, WAT also is induced by a variety of mechanisms, browning into brown adipose tissue (BAT). BAT is activated in CAC and greatly increases energy expenditure in patients. In addition, the production of lipid is reduced in CAC, and the cross-talk between adipose tissue and other systems, such as muscle tissue and immune system, also aggravates the progression of CAC. The treatment of CAC is still a vital clinical problem, and the abnormal lipid metabolism in CAC provides a new way for the treatment of CAC. In this article, we will review the mechanism of metabolic abnormalities of adipose tissue in CAC and its role in treatment.

Emerging roles of leptin in Parkinson's disease: Chronic inflammation, neuroprotection and more?

An increasing body of experimental evidence implicates a relationship between immunometabolic deterioration and the progression of Parkinson's disease (PD) with a dysregulation of central and peripheral neuroinflammatory networks mediated by circulating adipokines, in particular leptin. We screened the current literature on the role of adipokines in PD. Hence, we searched known databases (PubMed, MEDLINE/OVID) and reviewed original and review articles using the following terms: "leptin/ObR", "Parkinson's disease", "immune-metabolism", "biomarkers" and "neuroinflammation". Focusing on leptin, we summarize and discuss the existing in vivo and in vitro evidence on how adipokines may be protective against neurodegeneration, but at the same time contribute to the progression of PD. These components of the adipose brain axis represent a hitherto underestimated pathway to study systemic influences on dopaminergic degeneration. In addition, we give a comprehensive update on the potential of adjunctive therapeutics in PD targeting leptin, leptin-receptors, and associated pathways. Further experimental and clinical trials are needed to elucidate the mechanisms of action and the value of central and peripheral adipose-immune-metabolism molecular phenotyping in order to develop and validate the differential roles of different adipokines as potential therapeutic target for PD patients.

Inadequacy of Vitamin D Does Not Interfere with Body Weight Loss in Women of Reproductive Age after Roux-en-Y Gastric Bypass

Objective: To assess the influence of vitamin D on body weight loss in women who had previously undergone Roux-en-Y gastric bypass (RYGB). Methodology: This is an analytical, longitudinal and retrospective study comprising 40 women of reproductive age who had previously undergone RYGB. To investigate the influence of the serum concentrations of vitamin D on body weight reduction, the variables were analyzed in the pre-operative period (T0), in the first (T1) and in the second postoperative year (T2) and were stratified according to the BMI measured in T1 and T2. In addition, in the pre-operative period, participants were subdivided into groups based on adequacy (G1), deficiency (G2) and insufficiency (G3), according to their serum concentrations of vitamin D. Results: Although weight loss occurred in a substantial way in T1, it continued to decrease in T2 (p = 0.017). The women who reached normal weight within two years of surgery showed the lowest vitamin D concentrations preoperatively when compared to those who were overweight (p = 0.011). Women with preoperative vitamin D deficiency showed increased concentrations in the assessed times (p < 0.001), while the opposite (p = 0.001) occurred in women with adequacy. Conclusion: The study showed that inadequacy of vitamin D does not interfere with weight loss in the two-year-follow-up after RYGB and highlights that vitamin D can present a differentiated response postoperatively, to the detriment of the pre-operative period.

Identification of Differentially Expressed miRNAs in Porcine Adipose Tissues and Evaluation of Their Effects on Feed Efficiency

Feed efficiency (FE) is a very important trait affecting the economic benefits of pig breeding enterprises. Adipose tissue can modulate a variety of processes such as feed intake, energy metabolism and systemic physiological processes. However, the mechanism by which microRNAs (miRNAs) in adipose tissues regulate FE remains largely unknown. Therefore, this study aimed to screen potential miRNAs related to FE through miRNA sequencing. The miRNA profiles in porcine adipose tissues were obtained and 14 miRNAs were identified differentially expressed in adipose tissues of pigs with extreme differences in FE, of which 9 were down-regulated and 5 were up-regulated. GO and KEGG analyses indicated that these miRNAs were significantly related to lipid metabolism and these miRNAs modulated FE by regulating lipid metabolism. Subsequently, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) of five randomly selected DEMs was used to verify the reliability of miRNA-seq data. Furthermore, 39 differentially expressed target genes of these DEMs were obtained, and DEMs-target mRNA interaction networks were constructed. In addition, the most significantly down-regulated miRNAs, ssc-miR-122-5p and ssc-miR-192, might be the key miRNAs for FE. Our results reveal the mechanism by which adipose miRNAs regulate feed efficiency in pigs. This study provides a theoretical basis for the further study of swine feed efficiency improvement.

A simplified and defined serum-free medium for cultivating fat across species

Cultivated meat is a promising technology with the potential to mitigate the ethical and environmental issues associated with traditional meat. Fat plays a key role in the meat flavor; therefore, development of suitable adipogenic protocols for livestock is essential. The traditional adipogenic cocktail containing IBMX, dexamethasone, insulin and rosiglitazone is not food-compatible. Here, we demonstrate that of the four inducers only insulin and rosiglitazone are necessary in both serum-free (DMAD) and serum-containing media, with DMAD outperforming FBS. Two glucocorticoid receptor activators, progesterone and hydrocortisone, found in DMAD and FBS, affect differentiation homogeneity, without playing an essential role in activating adipogenic genes. Importantly, this protocol leads to mature adipocytes in 3D culture. This was demonstrated in both media types and in four species: ruminant and monogastric. We therefore propose a simplified one-step adipogenic protocol which, given the replacement of rosiglitazone by a food-compatible PPARγ agonist, is suitable for making cultivated fat.

Hypoxia as a Double-Edged Sword to Combat Obesity and Comorbidities

The global epidemic of obesity is tightly associated with numerous comorbidities, such as type II diabetes, cardiovascular diseases and the metabolic syndrome. Among the key features of obesity, some studies have suggested the abnormal expansion of adipose-tissue-induced local endogenous hypoxic, while other studies indicated endogenous hyperoxia as the opposite trend. Endogenous hypoxic aggravates dysfunction in adipose tissue and stimulates secretion of inflammatory molecules, which contribute to obesity. In contrast, hypoxic exposure combined with training effectively generate exogenous hypoxic to reduce body weight and downregulate metabolic risks. The (patho)physiological effects in adipose tissue are distinct from those of endogenous hypoxic. We critically assess the latest advances on the molecular mediators of endogenous hypoxic that regulate the dysfunction in adipose tissue. Subsequently we propose potential therapeutic targets in adipose tissues and the small molecules that may reverse the detrimental effect of local endogenous hypoxic. More importantly, we discuss alterations of metabolic pathways in adipose tissue and the metabolic benefits brought by hypoxic exercise. In terms of therapeutic intervention, numerous approaches have been developed to treat obesity, nevertheless durability and safety remain the major concern. Thus, a combination of the therapies that suppress endogenous hypoxic with exercise plans that augment exogenous hypoxic may accelerate the development of more effective and durable medications to treat obesity and comorbidities.

Immunogenicity of an mRNA-Based COVID-19 Vaccine among Adolescents with Obesity or Liver Transplants

There are limited data regarding the immunogenicity of mRNA-based SARS-CoV-2 vaccine BNT162b2 among immunosuppressed or obese adolescents. We evaluated the humoral immune response in adolescents with obesity and adolescent liver transplant recipients (LTRs) after receiving two BNT162b2 doses. Sixty-eight participants (44 males; mean age 14.9 ± 1.7 years), comprising 12 LTRs, 24 obese, and 32 healthy adolescents, were enrolled. Immunogenicity was evaluated by anti-SARS-CoV-2 spike protein immunoassay and surrogate viral neutralization tests (sVNT) against the Delta and Omicron (BA.1) variants. At 27.1 ± 3.2 days after the second dose, the antibody levels were 1476.6 ± 1185.4, 2999.4 ± 1725.9, and 4960.5 ± 2644.1 IU/mL in the LTRs, obese adolescents, and controls, respectively (p < 0.001). Among obese individuals, liver stiffness <5.5 kPa was associated with higher antibody levels. The %inhibition of sVNT was significantly lower for the Omicron than that for the Delta variant. Injection site pain was the most common local adverse event. Nine participants (three obese and six controls) developed COVID-19 at 49 ± 11 days after the second vaccination; four were treated with favipiravir. All infections were mild, and the patients recovered without any consequences. Our study supports the need for the booster regimen in groups with an inferior immunogenic response, including LTRs and obese individuals.

Several areas of overlap between obesity and aging indicate obesity as a biomarker of accelerated aging of human B cell function and antibody responses

Aging and obesity are high risk factors for several conditions and diseases. They are both associated with systemic inflammation and they are both ameliorated by a healthy life style, suggesting that they may share cellular and molecular pathways and underlying mechanisms. A close relationship between aging and obesity is also supported by the observation that the aging overweight/obese population is increasing worldwide, and mechanisms involved will be presented here. A focus of our work is to evaluate if obesity may be considered a good biomarker of accelerated aging of human antibody responses. We will summarize our published results showing the effects of obesity in accelerating age defects in the peripheral B cell pool and how these lead to dysfunctional humoral immunity.

Adipose-Secreted Exosomes and Their Pathophysiologic Effects on Skeletal Muscle

Due to its prominent secretory activity, adipose tissue (AT) is now considered a major player in the crosstalk between organs, especially with skeletal muscle. In which, exosomes are effective carriers for the intercellular material transfer of a wide range of molecules that can influence a series of physiological and pathological processes in recipient cells. Considering their underlying roles, the regulatory mechanisms of adipose-secreted exosomes and their cellular crosstalk with skeletal muscle have received great attention in the field. In this review, we describe what is currently known of adipose-secreted exosomes, as well as their applications in skeletal muscle pathophysiology.

Adipokines as Regulators of Autophagy in Obesity-Linked Cancer

Excess body weight and obesity have become significant risk factors for cancer development. During obesity, adipose tissue alters its biological function, deregulating the secretion of bioactive factors such as hormones, cytokines, and adipokines that promote an inflammatory microenvironment conducive to carcinogenesis and tumor progression. Adipokines regulate tumor processes such as apoptosis, proliferation, migration, angiogenesis, and invasion. Additionally, it has been found that they can modulate autophagy, a process implicated in tumor suppression in healthy tissue and cancer progression in established tumors. Since the tumor-promoting role of autophagy has been well described, the process has been suggested as a therapeutic target in cancer. However, the effects of targeting autophagy might depend on the tumor type and microenvironmental conditions, where circulating adipokines could influence the role of autophagy in cancer. Here, we review recent evidence related to the role of adipokines in cancer cell autophagy in an effort to understand the tumor response in the context of obesity under the assumption of an autophagy-targeting treatment.

The principle of 'brain energy on demand' and its predictive power for stress, sleep, stroke, obesity and diabetes

Does the brain actively draw energy from the body when needed? There are different schools of thought regarding energy metabolism. In this study, the various theoretical models are classified into one of two categories: (1) conceptualizations of the brain as being purely passively supplied, which we call 'P-models,' and (2) models understanding the brain as not only passively receiving energy but also actively procuring energy for itself on demand, which we call 'A-models.' One prominent example of such theories making use of an A-model is the selfish-brain theory. The ability to make predictions was compared between the A- and P-models. A-models were able to predict and coherently explain all data examined, which included stress, sleep, caloric restriction, stroke, type-1-diabetes mellitus, obesity, and type-2-diabetes, whereas the predictions of P-models failed in most cases. The strength of the evidence supporting A-models is based on the coherence of accurate predictions across a spectrum of metabolic states. The theory test conducted here speaks to a brain that pulls its energy from the body on-demand.

Dietary antioxidant intake is inversely associated with 2,3-dinor oxylipin metabolites, the major excreted oxylipins in overweight and obese subjects

Cardiometabolic disease risk factors, including obesity, insulin resistance, high blood pressure, and dyslipidemia, are associated with elevated oxidative stress biomarkers like oxylipins. Increased adiposity by itself induces various isomers of this oxidized lipid family, while dietary polyphenols show benefits in its regulation. Previously, we showed that specific co-abundant microorganisms characterized the gut microbiota of Colombians and associated differentially with diet, lifestyle, obesity, and cardiometabolic health status, which led us to hypothesize that urinary oxylipins would reflect the intensity of oxidative metabolism linked to gut microbiota dysbiosis. Thus, we selected a convenience sample of 105 participants (age: 40.2 ± 11.9 years, 47.6% women), grouped according to microbiota, cardiometabolic health status, and body mass index (BMI); and evaluated 33 urinary oxylipins by HPLC-QqQ-MS/MS (e.g., isoprostanes, prostaglandins, and metabolites), paired with anthropometry and blood chemistry information and dietary antioxidants estimated from a 24-h food recall. In general, oxylipins did not show differences among individuals who differed in gut microbiota. While the unmetabolized oxylipin levels were not associated with BMI, the total content of oxylipin metabolites was highest in obese and cardiometabolically abnormal subjects (e.g., insulin resistant), mainly by prostaglandin-D (2,3-dinor-11β-PGF_2α) and 15-F_2t-IsoPs (2,3-dinor-15-F_2t-IsoP and 2,3-dinor-15-epi-15-F_2t-IsoP) metabolites. The total polyphenol intake in this cohort was 1070 ± 627 mg/day. After adjusting for body weight, the polyphenol intake was significantly higher in lean than overweight and showed an inverse association with dinor-oxylipin levels in principal component analysis. These results suggest that the 2,3-dinor-oxylipins could be more specific biomarkers associated with BMI than their parent oxylipins and that are sensitive to be regulated by dietary antioxidants.

Effect of cholesterol-lowering agents on soluble epidermal growth factor receptor level in type 2 diabetes and hypercholesterolemia

Soluble epidermal growth factor receptor (sEGFR) levels are elevated in patients with type 2 diabetes mellitus (T2DM) and positively correlate with blood glucose and cholesterol levels. However, how cholesterol-lowering treatment in patients with T2DM affects the sEGFR level is unknown. Therefore, we investigated the change of serum sEGFR after cholesterol-lowering treatment in type 2 diabetic patients with hypercholesterolemia. This study is a non-randomized, prospective observational study. A total of 115 patients were treated in either the rosuvastatin monotherapy group (R group, 5 mg/day, n = 59) or the rosuvastatin/ezetimibe combination therapy group (RE group, 5 mg/10 mg/day, n = 56) for 12 weeks. We measured serum levels of lipids and sEGFR using an ELISA kit before and after 12 weeks of treatment in each group. The low-density lipoprotein cholesterol (LDL-C) level was significantly reduced (from 130.27 ± 27.09 to 76.24 ± 26.82 mg/dL; P < .001) after 12 weeks of treatment and more so in the RE group than in the R group (from 131.68 ± 28.72 to 87.13 ± 27.04 mg/dL, P < .001 in the R group; from 128.78 ± 25.58 to 64.75 ± 21.52 mg/dL, P < .001 in the RE group; R vs RE group, P < .001). The sEGFR level was significantly decreased after 12 weeks of treatment (from 50.34 ± 13.31 to 45.75 ± 11.54 ng/mL; P = .007). The RE group only showed a significant reduction in the sEGFR level after treatment (from 50.94 ± 12.10 to 44.80 ± 11.36 ng/mL; P = .007). Moreover, the sEGFR level was significantly reduced only when the LDL-C level was significantly reduced (from 50.46 ± 10.66 to 46.24 ± 11.86 ng/mL; P = .043). The serum sEGFR level was significantly reduced by cholesterol-lowering treatment with rosuvastatin alone or rosuvastatin/ezetimibe. We suggested that sEGFR may play a significant role in insulin resistance (IR) and inflammation, which are central pathophysiological mechanisms. We confirmed the possibility of using sEGFR as a biomarker to predict a good response to lipid-lowering treatment in type 2 diabetes patients with hypercholesterolemia.

Effect of Lauric vs. Oleic Acid-Enriched Diets on Leptin Autoparacrine Signalling in Male Mice

High-fat diets enriched with lauric acid (SOLF) do not enhance leptin production despite expanding white adipose tissue (WAT). Our study aimed at identifying the influence of SOLF vs. oleic acid-enriched diets (UOLF) on the autoparacrine effect of leptin and was carried out on eight-week-old mice consuming control chow, UOLF or SOLF. Phosphorylation of kinases integral to leptin receptor (LepR) signalling pathways (705Tyr-STAT3, 473Ser-Akt, 172Thr-AMPK), adipocyte-size distribution, fatty acid content, and gene expression were analyzed in WAT. SOLF enhanced basal levels of phosphorylated proteins but reduced the ability of leptin to enhance kinase phosphorylation. In contrast, UOLF failed to increase basal levels of phosphorylated proteins and did not modify the effect of leptin. Both SOLF and UOLF similarly affected adipocyte-size distribution, and the expression of genes related with adipogenesis and inflammation. WAT composition was different between groups, with SOLF samples mostly containing palmitic, myristic and lauric acids (>48% w/w) and UOLF WAT containing more than 80% (w/w) of oleic acid. In conclusion, SOLF appears to be more detrimental than UOLF to the autoparacrine leptin actions, which may have an impact on WAT inflammation. The effect of SOLF and UOLF on WAT composition may affect WAT biophysical properties, which are able to condition LepR signaling.

PCSK9 and Other Metabolic Targets to Counteract Ischemia/Reperfusion Injury in Acute Myocardial Infarction and Visceral Vascular Surgery

Ischemia/reperfusion (I/R) injury complicates both unpredictable events (myocardial infarction and stroke) as well as surgically-induced ones when transient clampage of major vessels is needed. Although the main cause of damage is attributed to mitochondrial dysfunction and oxidative stress, the use of antioxidant compounds for protection gave poor results when challenged in clinics. More recently, there is an assumption that, in humans, profound metabolic changes may prevail in driving I/R injury. In the present work, we narrowed the field of search to I/R injury in the heart/brain/kidney axis in acute myocardial infarction, major vascular surgery, and to the current practice of protection in both settings; then, to help the definition of novel strategies to be translated clinically, the most promising metabolic targets with their modulatory compounds—when available—and new preclinical strategies against I/R injury are described. The consideration arisen from the broad range of studies we have reviewed will help to define novel therapeutic approaches to ensure mitochondrial protection, when I/R events are predictable, and to cope with I/R injury, when it occurs unexpectedly.

A comprehensive look into the association of vitamin D levels and vitamin D receptor gene polymorphism with obesity in children

Childhood obesity accounts for several psychosocial and clinical consequences. Psychosocial consequences include lower self-esteem, social isolation, poor academic achievement, peer problems, and depression, whereas clinical consequences are cardiovascular diseases, type 2 diabetes, dyslipidemia, cancer, autoimmune diseases, girls early polycystic ovarian syndrome (PCOS), asthma, bone deformities, etc. A growing number of studies have uncovered the association of childhood obesity and its consequences with vitamin-D (vit-D) deficiency and vitamin-D receptor (VDR) gene polymorphisms such as single nucleotide polymorphisms (SNPs), e.g., TaqI, BsmI, ApaI, FokI, and Cdx2. Considering the impact of vit-D deficiency and VDR gene polymorphisms, identifying associated factors and risk groups linked to lower serum vit-D levels and prevention of obesity-related syndromes in children is of utmost importance. Previously published review articles mainly focused on the association of vit-D deficiency with obesity or other non-communicable diseases in children. The nature of the correlation between vit-D deficiency and VDR gene polymorphisms with obesity in children is yet to be clarified. Therefore, this review attempts to delineate the association of obesity with these two factors by identifying the molecular mechanism of the relationship.

Towards harnessing the value of organokine crosstalk to predict the risk for cardiovascular disease in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. Importantly, NAFLD increases the risk for cardiovascular disease (CVD). A causal relationship has been substantiated. Given the pandemic proportions of NAFLD, a reliable scoring system for predicting the risk of NAFLD-associated CVD is an urgent medical need. We here review cumulative evidence suggesting that systemically released organokines - especially certain adipokines, hepatokines, and cardiokines - may serve this purpose. The underlying rationale is that these signalers directly communicate between white adipose tissue, liver, and heart as key players in the pathogenesis of NAFLD and resultant CVD events. Moreover, evidence suggests that these organ-specific cytokines are secreted in a biologically predetermined, cascade-like pattern. Consequently, upon pinpointing organokines of relevance, we sketch requirements to establish an algorithm predictive of the CVD risk in patients with NAFLD. Such an algorithm, as to be consolidated in the form of an applicable equation, may be improved continuously by machine learning. To the best of our knowledge, such an option has not yet been considered. Establishing and implementing a reliable algorithm for determining the NAFLD-associated CVD risk has the potential to save many NAFLD patients from life-threatening CVD events.

Clinical, Laboratory, and Histologic Correlates of Serum Antinuclear Antibody in Hispanic Pediatric Patients With Nonalcoholic Fatty Liver Disease

OBJECTIVES

The significance of antinuclear antibody (ANA) positivity in pediatric Hispanic patients with nonalcoholic fatty liver disease (NAFLD) is unknown.

METHODS

ANA status was correlated with clinical, laboratory, and histologic parameters in Hispanic patients with a histologic diagnosis of NAFLD.

RESULTS

Thirty-eight Hispanic children (27 male and 11 female) underwent liver biopsy at a median age of 12.1 years. Twenty patients (53%) had positive ANAs. The ANA-positive patients had higher fasting insulin levels (median [interquartile range (IQR)], 32.4 [25.4] µU/mL) and higher insulin resistance (median [Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) IQR], 5.9 [3.1]) than the ANA-negative patients (fasting insulin: median [IQR], 17 [13.9] µU/mL and median [HOMA-IR IQR], 3.5 [2.6] µU/mL; P = .05 and .01, respectively). Serum high-density lipoprotein (HDL) cholesterol levels were higher in the ANA-negative patients (median [IQR], 47 [18] mg/dL) than the ANA-positive patients (38 [12] mg/dL) (P = .03). There were no statistical differences in a series of demographic, clinical, laboratory, and histologic parameters between the ANA-positive and the ANA-negative patients. At a median follow-up of 2.6 years, alanine aminotransferase was significantly lower than the baseline levels in both groups. In 1 patient undergoing ANA retesting, the titer had normalized from a baseline of 1:1,280 3.8 years earlier.

CONCLUSIONS

In pediatric Hispanic patients with NAFLD, a positive ANA result is associated with insulin resistance and lower HDL cholesterol levels.

Tanshinone IIA and its derivative activate thermogenesis in adipocytes and induce "beiging" of white adipose tissue

Tanshinone IIA (TAN2A) is a major active ingredient of Salvia miltiorrhiza used in traditional Chinese medicine and tanshinone 20 (TAN20) is a derivative of TAN2A. In this study, we examined the effects of TAN2A and TAN20 on adipogenesis, lipid metabolism, and thermogenesis. Our experiments showed that both TAN2A and TAN20 increased mitochondria content in adipose tissue, enhanced energy expenditure, reduced body weight, and improved insulin sensitivity and metabolic homeostasis in obese and diabetic mouse models. We demonstrated that TAN20 can facilitate the transformation from white to beige adipose tissue, as well as activate brown adipose tissue. In uncoupling protein 1 (UCP1) knockout mouse model, the effects of TAN2A and TAN20 on body weight and glucose tolerance were not observed, suggesting that such effects were UCP1 dependent. Furthermore, we found that TAN2A and TAN20 increased the expression of UCP1 and other thermogenic genes in adipocytes through AMPK-PGC-1α signaling pathway. Our findings indicate that TAN2A and its derivative TAN20 are potential interesting energy expenditure regulators and may be implicated in treatment of obesity and other metabolic disorders.

Loss of Human Beta Cell Identity in a Reconstructed Omental Stromal Cell Environment

In human type 2 diabetes, adipose tissue plays an important role in disturbing glucose homeostasis by secreting factors that affect the function of cells and tissues throughout the body, including insulin-producing pancreatic beta cells. We aimed here at studying the paracrine effect of stromal cells isolated from subcutaneous and omental adipose tissue on human beta cells. We developed an in vitro model wherein the functional human beta cell line EndoC-βH1 was treated with conditioned media from human adipose tissues. By using RNA-sequencing and western blotting, we determined that a conditioned medium derived from omental stromal cells stimulates several pathways, such as STAT, SMAD and RELA, in EndoC-βH1 cells. We also observed that upon treatment, the expression of beta cell markers decreased while dedifferentiation markers increased. Loss-of-function experiments that efficiently blocked specific signaling pathways did not reverse dedifferentiation, suggesting the implication of more than one pathway in this regulatory process. Taken together, we demonstrate that soluble factors derived from stromal cells isolated from human omental adipose tissue signal human beta cells and modulate their identity.

Gender differences in cardiometabolic health and disease in a cross-sectional observational obesity study

Background

Beyond the degree of adiposity, the pattern of fat distribution has a profound influence on cardiometabolic risk. It is unclear if sex differences in body fat distribution can potentially explain any sex differences in the prevalence of the metabolic syndrome (MetS) and in individual cardiometabolic risk factors among obese men and women.

Methods

In this cross-sectional analysis, 432 persons from the ongoing Obesity Weight Reduction Study (n = 356 obese, ØBMI 41 ± 8 kg/m², and 76 non-obese, ØBMI 25 ± 3 kg/m²), were included. The relations of sex to MetS prevalence and selected cardiometabolic risk factors were assessed using univariate and multivariate adjusted regression models.

Results

In crude analyses, %fat mass and the fat mass/lean mass ratio were significantly higher in women than in men, regardless of increasing obesity categories, from normal weight to grade-3-obesity. In contrast, markers of abdominal obesity, such as waist circumference and waist-to-hip ratio were higher in men than in women, despite similar BMI. The prevalence of the MetS was higher in obese men than in women (67.6 vs. 45.0%, p < 0.0001), particularly in younger individuals < 40 years (72.5 vs. 36.8%, p < 0.0001), but “metabolically healthy obesity” (BMI ≥ 30, no other NCEP ATPIII MetS component) was more common in women than in men (15.6 vs. 4.1%, p < 0.0001). After adjusting for age, %body fat and height, sex differences were observed for HDL-cholesterol (p < 0.001), triglycerides (p < 0.001), fasting glucose (p = 0.002), insulin and HOMA-IR levels (p < 0.001), ALAT (p < 0.001), adiponectin (p < 0.001), and sE-selectin (p = 0.005). In contrast, crude sex differences in other variables, such as leptin levels (68 ± 4 in obese women vs. 33 ± 2 µg/L in men, p < 0.0001), disappeared after accounting for differences in %body fat (least-squares means of leptin: 52 ± 4 vs. 55 ± 6 µg /L, p = 0.740). A logistic regression model adjusting for age and lifestyle factors revealed a lower risk of having MetS for women as compared to men (OR = 0.38[0.22–0.60]). That risk estimate did not materially alter after adding BMI to the model. In contrast, no statistically significant association between sex and MetS prevalence was observed after adding waist circumference and adiponectin to the model (OR = 1.41[0.59–3.36]).

Conclusions

Different body fat distribution patterns, particularly abdominal adiposity, adiponectin, and related biomarkers, may contribute to sex differences in cardiometabolic risk factors and to the prevalence of the MetS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-022-00416-4.

Reduced production of isoprostanes by peri-pancreatic adipose tissue from Zucker fa/fa rats as a new mechanism for β-cell compensation in insulin resistance and obesity

During early stages of type 2 diabetes, named prediabetes, pancreatic β-cells compensate for insulin resistance through increased insulin secretion in order to maintain normoglycemia. Obesity leads to the development of ectopic fat deposits, among which peri-pancreatic white adipose tissue (pWAT) can communicate with β-cells through soluble mediators. Thus we investigated whether pWAT produced oxygenated lipids, namely isoprostanes and neuroprostanes and whether they can influence β-cell function in obesity. In the Zucker fa/fa rat model, pWAT and epididymal white adipose tissue (eWAT) displayed different inflammatory profiles. In obese rats, pWAT, but not eWAT, released less amounts of 5-F_2t-isoprostanes, 15-F_2t-isoprostanes, 4-F_4t-neuroprostanes and 10-F_4t-neuroprostane compared to lean animals. These differences could be explained by a greater induction of antioxidant defenses enzymes such as SOD-1, SOD-2, and catalase in pWAT of obese animals compared to eWAT. In addition, sPLA2 IIA, involved in the release of isoprostanoids from cellular membranes, was decreased in pWAT of obese animals, but not in eWAT, and may also account for the reduced release of oxidized lipids by this tissue. At a functional level, 15-F_2t-isoprostane epimers, but not 5-F_2t-isoprostanes, were able to decrease glucose-induced insulin secretion in pancreatic islets from Wistar rats. This effect appeared to be mediated through activation of the thromboxane A2 receptor and reduction of cAMP signaling in pancreatic islets. In conclusion, through the removal of an inhibitory tone exerted by isoprostanes, we have shown, for the first time, a new mechanism allowing β-cells to compensate for insulin resistance in obesity that is linked to a biocommunication between adipose tissue and β-cells.

Screening and Identification of Putative Long Non-Coding RNA in Childhood Obesity: Evaluation of Their Transcriptional Levels

Background and Methods: Long non-coding RNAs (LncRNAs) and microRNAs are involved in the pathogenesis of obesity, a multifactorial disease that is characterized by inflammation, cardiometabolic complications, and increased cancer risk among other co-morbidities. The up/down regulation of LncRNAs and microRNAs may play an important role in this condition to identify new diagnostic/prognostic markers. The aim of the study was to identify circulating inflammatory LncRNAs in obese adolescents (n = 54) and to evaluate whether their expression behaved differently compared to normal-weight adolescents (n = 26). To have a more complete insight, the expression of some circulating miRNAs that are linked to obesity (miR-33a, miR-223, miR-142, miR-199a, miR-181a, and miR-4454) were also analyzed. Results: LncRNAs and miRNAs were extracted simultaneously from plasma samples and amplified by Real-Time PCR. Among the 86 LncRNAs that were analyzed with custom pre-designed plates, only four (RP11-347E10.1, RP11-10K16.1, LINC00657, and SNHG12) were amplified in both normal-weight and obese adolescents and only SNHG12 showed significantly lower expression compared to the normal-weight adolescents (p = 0.026). Circulating miRNAs showed a tendency to increase in obese subjects, except for miR-181a expression. LncRNAs and miRNAs correlated with some clinical and metabolic parameters. Conclusions: Our results suggest the importance of these new biomarkers to better understand the molecular mechanisms of childhood obesity and its metabolic disorder.

Symposium review: Adipose tissue endocrinology in the periparturient period of dairy cows

The involvement of adipose tissue (AT) in metabolism is not limited to energy storage but turned out to be much more complex. We now know that in addition to lipid metabolism, AT is important in glucose homeostasis and AA metabolism and also has a role in inflammatory processes. With the discovery of leptin in 1994, the concept of AT being able to secrete messenger molecules collectively termed as adipokines, and acting in an endo-, para-, and autocrine manner emerged. Moreover, based on its asset of receptors, many stimuli from other tissues reaching AT via the bloodstream can also elicit distinct responses and thus integrate AT as a control element in the regulatory circuits of the whole body's functions. The protein secretome of human differentiated adipocytes was described to comprise more than 400 different proteins. However, in dairy cows, the characterization of the physiological time course of adipokines in AT during the transition from pregnancy to lactation is largely limited to the mRNA level; for the protein level, the analytical methods are limited and available assays often lack sound validation. In addition to proteinaceous adipokines, small compounds such as steroids can also be secreted from AT. Due to the lipophilic nature of steroids, they are stored in AT, but during the past years, AT became also known as being able to metabolize and even to generate steroid hormones de novo. In high-yielding dairy cows, AT is substantially mobilized due to increased energy requirements related to lactation. As to whether the steroidogenic system in AT is affected and may change during the common loss of body fat is largely unknown. Moreover, most research about AT in transition dairy cows is based on subcutaneous AT, whereas other depots have scarcely been investigated. This contribution aims to review the changes in adipokine mRNA and-where available-protein expression with time relative to calving in high-yielding dairy cows at different conditions, including parity, body condition, diet, specific feed supplements, and health disorders. In addition, the review provides insights into steroidogenic pathways in dairy cows AT, and addresses differences between fat depots where possible.

Macrophages in epididymal adipose tissue secrete osteopontin to regulate bone homeostasis

Epididymal white adipose tissue (eWAT) secretes an array of cytokines to regulate the metabolism of organs and tissues in high-fat diet (HFD)-induced obesity, but its effects on bone metabolism are not well understood. Here, we report that macrophages in eWAT are a main source of osteopontin, which selectively circulates to the bone marrow and promotes the degradation of the bone matrix by activating osteoclasts, as well as modulating bone marrow-derived macrophages (BMDMs) to engulf the lipid droplets released from adipocytes in the bone marrow of mice. However, the lactate accumulation induced by osteopontin regulation blocks both lipolysis and osteoclastogenesis in BMDMs by limiting the energy regeneration by ATP6V0d2 in lysosomes. Both surgical removal of eWAT and local injection of either clodronate liposomes (for depleting macrophages) or osteopontin-neutralizing antibody show comparable amelioration of HFD-induced bone loss in mice. These results provide an avenue for developing therapeutic strategies to mitigate obesity-related bone disorders.

Polycystic ovary syndrome as a plausible evolutionary outcome of metabolic adaptation

As a common endocrinopathy of reproductive-aged women, polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo-anovulation and polycystic ovarian morphology. It is linked with insulin resistance through preferential abdominal fat accumulation that is worsened by obesity. Over the past two millennia, menstrual irregularity, male-type habitus and sub-infertility have been described in women and confirm that these clinical features of PCOS were common in antiquity. Recent findings in normal-weight hyperandrogenic PCOS women show that exaggerated lipid accumulation by subcutaneous (SC) abdominal stem cells during development to adipocytes in vitro occurs in combination with reduced insulin sensitivity and preferential accumulation of highly-lipolytic intra-abdominal fat in vivo. This PCOS phenotype may be an evolutionary metabolic adaptation to balance energy storage with glucose availability and fatty acid oxidation for optimal energy use during reproduction. This review integrates fundamental endocrine-metabolic changes in healthy, normal-weight PCOS women with similar PCOS-like traits present in animal models in which tissue differentiation is completed during fetal life as in humans to support the evolutionary concept that PCOS has common ancestral and developmental origins.

The Interactions between Adipose Tissue Secretions and Parkinson's disease; The Role of Leptin

Leptin is a hormone that regulates appetite by acting on receptors in the hypothalamus, where it modifies food intake to maintain equilibrium with the body energy resources. Leptin and its receptors are widely distributed in the central nervous system, suggesting that they may give neuronal survival signals. The potential of leptin to decrease/increase neuronal damage and neuronal plasticity in Parkinson's diseases (PD) is the subject of this review, which outlines our current knowledge of how leptin acts in the brain. Although leptin-mediated neuroprotective signaling results in neuronal death prevention, it can affect neuroinflammatory cascades and also neuronal plasticity which contribute to PD pathology. Other neuroprotective molecules, such as insulin and erythropoietin, share leptin-related signaling cascades, and therefore constitute a component of the neurotrophic effects mediated by endogenous hormones. With the evidence that leptin dysregulation causes increased neuronal vulnerability to damage in PD, using leptin as a target for therapeutic modification is an appealing and realistic option.

Sphingolipids in Adipose: Kin or Foe?

Obesity research has shifted in recent years to address not only the total amount of adipose tissue present in an individual but also to include adipose tissue functions such as endocrine function and thermogenesis. Data suggest that sphingolipids are critical regulators of metabolic homeostasis, and that disruption of their levels is associated with metabolic disease. Abundant data from mouse models has revealed both beneficial and deleterious roles for sphingolipids in adipose function, and numerous human studies have shown that obesity alters circulating sphingolipid profiles. Sphingolipids comprise a large family of interrelated metabolites, and pinpointing specific functions for specific lipids will be required to fully exploit the therapeutic potential of targeting sphingolipids to treat obesity and related disorders.

Adipokines, Hepatokines and Myokines: Focus on Their Role and Molecular Mechanisms in Adipose Tissue Inflammation

Chronic low-grade inflammation in adipose tissue (AT) is a hallmark of obesity and contributes to various metabolic disorders, such as type 2 diabetes and cardiovascular diseases. Inflammation in ATs is characterized by macrophage infiltration and the activation of inflammatory pathways mediated by NF-κB, JNK, and NLRP3 inflammasomes. Adipokines, hepatokines and myokines - proteins secreted from AT, the liver and skeletal muscle play regulatory roles in AT inflammation via endocrine, paracrine, and autocrine pathways. For example, obesity is associated with elevated levels of pro-inflammatory adipokines (e.g., leptin, resistin, chemerin, progranulin, RBP4, WISP1, FABP4, PAI-1, Follistatin-like1, MCP-1, SPARC, SPARCL1, and SAA) and reduced levels of anti-inflammatory adipokines such as adiponectin, omentin, ZAG, SFRP5, CTRP3, vaspin, and IL-10. Moreover, some hepatokines (Fetuin A, DPP4, FGF21, GDF15, and MANF) and myokines (irisin, IL-6, and DEL-1) also play pro- or anti-inflammatory roles in AT inflammation. This review aims to provide an updated understanding of these organokines and their role in AT inflammation and related metabolic abnormalities. It serves to highlight the molecular mechanisms underlying the effects of these organokines and their clinical significance. Insights into the roles and mechanisms of these organokines could provide novel and potential therapeutic targets for obesity-induced inflammation.