Insulin signalling mechanisms for triacylglycerol storage

Age-related retinal degeneration resulting from the deletion of Shp2 tyrosine phosphatase in photoreceptor neurons

Shp2, a critical SH2-domain-containing tyrosine phosphatase, is essential for cellular regulation and implicated in metabolic disruptions, obesity, diabetes, Noonan syndrome, LEOPARD syndrome, and cancers. This study focuses on Shp2 in rod photoreceptor cells, revealing its enrichment, particularly in rods. Deletion of Shp2 in rods leads to age-dependent photoreceptor degeneration. Shp2 targets occludin (OCLN), a tight junction protein, and its deletion reduces OCLN expression in the retina and retinal pigment epithelium (RPE). The isolation of actively translating mRNAs from rods lacking Shp2, followed by RNA sequencing, reveals alterations in cell cycle regulation. Additionally, altered retinal metabolism is observed in retinal cells lacking Shp2. Our studies indicate that Shp2 is crucial for maintaining the structure and function of photoreceptors.

TRAF6-mediated ubiquitination of AKT1 in the nucleus occurs in a β-arrestin2-dependent manner upon insulin stimulation

AKT, also known as protein kinase B (PKB), serves as a crucial regulator of numerous biological functions, including cell growth, metabolism, and tumorigenesis. Increasing evidence suggests that the kinase activity of AKT is regulated via ubiquitination by various E3 ligase enzymes in response to different stimuli. However, the molecular mechanisms underlying insulin-induced AKT ubiquitination are not yet fully understood. Here, we show that activation of the insulin receptor (IR) leads to enhanced ubiquitination of AKT1 at K8 and K14 residues, facilitated by the cytosolic E3 ubiquitin ligase enzyme, TRAF6. Further investigation using AKT1 mutants with modified nucleocytoplasmic shuttling properties reveals that TRAF6-mediated AKT1 ubiquitination occurs within the nucleus in a β-Arr2-dependent manner. The nuclear entry of TRAF6 depends on importin β1, while β-Arr2 regulates this process by facilitating the interaction between TRAF6 and importin β1. Additionally, the ubiquitination of AKT1 is essential for its translocation to the activated IR on the plasma membrane, where it plays a functional role in recruiting Glut4 and facilitating glucose uptake. This study uncovers the cellular components and processes involved in insulin-induced ubiquitination and activation of AKT1, providing insights and detailed strategies for manipulating AKT1.

Adipocyte-specific FAK deletion promotes pancreatic β-cell apoptosis via adipose inflammatory response to exacerbate diabetes mellitus

BACKGROUND

White adipose tissue (WAT) has a key role in maintaining energy balance throughout the body, and their dysfunction take part in the regulation of diabetes mellitus. However, the internal regulatory mechanisms underlying are still unknown.

METHODS AND RESULTS

We generated adipocyte-specific FAK KO (FAK-AKO) mice and investigated their phenotype. The cascade of adipocyte, macrophage in adipocyte tissues, and pancreatic β-cells were proposed in FAK-AKO mice and validated by cell line studies using 3T3-L1, Raw264.7 and Min6. The FAK-AKO mice exhibited glucose intolerance, reduced adipose tissue mass and increased apoptosis, lipolysis and inflammatory response in adipose tissue. We further demonstrate that adipocyte FAK deletion increases β cell apoptosis and inflammatory infiltrates into islets, which is potentiated if mice were treated with STZ. In the STZ-induced diabetes model, FAK AKO mice exhibit less serum insulin content and pancreatic β cell area. Moreover, serum pro-inflammatory factors increased and insulin levels decreased after glucose stimulation in FAK AKO mice. In a parallel vitro experiment, knockdown or inhibition of FAK during differentiation also increased apoptosis, lipolysis and inflammatory in 3T3-L1 adipocytes, whereas the opposite was observed upon overexpression of FAK. Moreover, coculturing LPS-treated RAW264.7 macrophages with knockdown FAK of 3T3-L1 adipocytes increased macrophage pro-inflammatory response. Furthermore, conditioned medium from above stimulated Min6 cells apoptosis (with or without STZ), whereas the opposite was observed upon overexpression of FAK. Mechanistically, FAK protein interact with TRAF6 in adipocytes and knockdown or inhibition of FAK activated TRAF6/TAK1/NF-κB signaling, which exacerbates inflammation of adipocytes themselves.

CONCLUSION

Adipocyte FAK deletion promotes both adipocyte apoptosis and adipose tissue inflammation. Pro-inflammatory factors released by the FAK-null adipose tissue further trigger apoptosis in pancreatic islets induced by the administration of STZ, thereby exacerbating the diabetes mellitus. This study reveals a link between FAK-mediated adipose inflammation and diabetes mellitus, a mechanism that has not been previously recognized.

Long-term ketogenic diet causes hyperlipidemia, liver dysfunction, and glucose intolerance from impaired insulin trafficking and secretion in mice

A ketogenic diet (KD) is a very low-carbohydrate, very high-fat diet proposed to treat obesity and type 2 diabetes. While KD grows in popularity, its effects on metabolic health are understudied. Here we show that, in male and female mice, while KD protects against weight gain and induces weight loss, over long-term, mice develop hyperlipidemia, hepatic steatosis, and severe glucose intolerance. Unlike high fat diet-fed mice, KD mice are not insulin resistant and have low levels of insulin. Hyperglycemic clamp and ex vivo GSIS revealed cell-autonomous and whole-body impairments in insulin secretion. Major ER/Golgi stress and disrupted ER-Golgi protein trafficking was indicated by transcriptomic profiling of KD islets and confirmed by electron micrographs showing a dilated Golgi network likely responsible for impaired insulin granule trafficking and secretion. Overall, our results suggest long-term KD leads to multiple aberrations of metabolic parameters that caution its systematic use as a health promoting dietary intervention.

Fibro-adipogenic progenitors in physiological adipogenesis and intermuscular adipose tissue remodeling

Excessive accumulation of intermuscular adipose tissue (IMAT) is a common pathological feature in various metabolic and health conditions and can cause muscle atrophy, reduced function, inflammation, insulin resistance, cardiovascular issues, and unhealthy aging. Although IMAT results from fat accumulation in muscle, the mechanisms underlying its onset, development, cellular components, and functions remain unclear. IMAT levels are influenced by several factors, such as changes in the tissue environment, muscle type and origin, extent and duration of trauma, and persistent activation of fibro-adipogenic progenitors (FAPs). FAPs are a diverse and transcriptionally heterogeneous population of stromal cells essential for tissue maintenance, neuromuscular stability, and tissue regeneration. However, in cases of chronic inflammation and pathological conditions, FAPs expand and differentiate into adipocytes, resulting in the development of abnormal and ectopic IMAT. This review discusses the role of FAPs in adipogenesis and how they remodel IMAT. It highlights evidence supporting FAPs and FAP-derived adipocytes as constituents of IMAT, emphasizing their significance in adipose tissue maintenance and development, as well as their involvement in metabolic disorders, chronic pathologies and diseases. We also investigated the intricate molecular pathways and cell interactions governing FAP behavior, adipogenesis, and IMAT accumulation in chronic diseases and muscle deconditioning. Finally, we hypothesize that impaired cellular metabolic flexibility in dysfunctional muscles impacts FAPs, leading to IMAT. A deeper understanding of the biology of IMAT accumulation and the mechanisms regulating FAP behavior and fate are essential for the development of new therapeutic strategies for several debilitating conditions.

Adipose organ dysfunction and type 2 diabetes: Role of nitric oxide

Adipose organ, historically known as specialized lipid-handling tissue serving as the long-term fat depot, is now appreciated as the largest endocrine organ composed of two main compartments, i.e., subcutaneous and visceral adipose tissue (AT), madding up white and beige/brown adipocytes. Adipose organ dysfunction manifested as maldistribution of the compartments, hypertrophic, hypoxic, inflamed, and insulin-resistant AT, contributes to the development of type 2 diabetes (T2D). Here, we highlight the role of nitric oxide (NO·) in AT (dys)function in relation to developing T2D. The key aspects determining lipid and glucose homeostasis in AT depend on the physiological levels of the NO· produced via endothelial NO· synthases (eNOS). In addition to decreased NO· bioavailability (via decreased expression/activity of eNOS or scavenging NO·), excessive NO· produced by inducible NOS (iNOS) in response to hypoxia and AT inflammation may be a critical interfering factor diverting NO· signaling to the formation of reactive oxygen and nitrogen species, resulting in AT and whole-body metabolic dysfunction. Pharmacological approaches boosting AT-NO· availability at physiological levels (by increasing NO· production and its stability), as well as suppression of iNOS-NO· synthesis, are potential candidates for developing NO·-based therapeutics in T2D.

Lusianthridin ameliorates high fat diet-induced metabolic dysfunction-associated fatty liver disease via activation of FXR signaling pathway

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a common chronic liver disease, but there are few specific medications for it. Lusianthridin, a major phenanthrene component that originates from Dendrobium Sonia, has various in vitro biological functions. In this study, we aimed to evaluate the therapeutic effects of lusianthridin on high-fat diet (HFD)-induced MAFLD as well as to examine the mechanism of its effects. We fed male mice high-fat-diet for 12 weeks to induce MAFLD and then continued to feed them, either with or without lusianthridin, for another six weeks. We found that lusianthridin decreased serum triacylglycerol, hepatic triacylglycerol, and serum low density lipoprotein cholesterol. It also reduced hepatic lipid accumulation based on the results of morphology analysis. Besides, it improved hepatic inflammation as well, including a decrease in serum alanine aminotransferase and a reduction in macrophage and neutrophil infiltration. Mechanistically, surface plasmon resonance, cell thermal shift assay and dual-luciferase report system results suggested that lusianthridin combined with farnesoid X receptor (FXR) ligand binding region and activated its transcriptional activity. Lusianthridin also decreased de no lipogenesis though inhibiting Srebp1c and downstream Scd-1, Lpin1 and Dgat2 expression in a FXR-dependent manner in oleic acid treated L02 cells. Correspondingly, lusianthridin inhibited Srebp1c and downstream lipogenesis in MAFLD liver tissues of mice at both of genetic and protein levels. Finally, the protective effects of lusianthridin on hepatic steaotosis were abolished in Fxr-/- mice. Taken together, our results suggested that lusianthridin attenuated high-fat-diet induced MAFLD via activation the FXR signaling pathway.

Polymicrobial Infection Induces Adipose Tissue Dysfunction via Gingival Extracellular Vesicles

Recent studies have indicated that periodontitis promotes metabolic dysregulation and insulin resistance by affecting the function of white adipose tissue (WAT). However, the mechanisms linking periodontitis to adipose tissue dysfunction still need to be explored. Extracellular vesicles (EVs) deliver messages to distal sites and regulate their function. Also, recent studies have shown that periodontitis changes the composition of EVs in body fluids and that EVs might be one of the mechanisms underlying the relationship between periodontitis and insulin resistance. Herein, we explored the impact of polymicrobial oral infection with periodontal pathogens on the function of WAT and the role of gingival EVs (gEVs) in the process. Mice were subjected to oral inoculation with 109 Porphyromonas gingivalis and 108 Fusobacterium nucleatum every other day for 14 wk. This prolonged bacterial infection induced WAT dysfunction, characterized by reduced levels of AKT phosphorylation, adiponectin, leptin, and genes associated with adipogenesis and lipogenesis. We successfully isolated gEVs with satisfactory yield and purity. The RNA sequencing results showed that the differentially expressed microRNAs in the gEVs of mice with polymicrobial oral infection were involved in insulin signaling and adipose tissue function. Notably, our in vitro experiments and RNA sequencing results revealed the functional similarities between gEVs and plasma-derived EVs. Furthermore, intraperitoneal injection with gEVs derived from mice with oral infection induced the dysfunction of WAT in healthy mice. Overall, our findings provide evidence for the influence of polymicrobial oral infection on WAT function and propose gEVs as a novel pathway through which periodontal infection may exert its effects on WAT.

Localization, traffic and function of Rab34 in adipocyte lipid and endocrine functions

BACKGROUND

Excessive lipid accumulation in the adipose tissue in obesity alters the endocrine and energy storage functions of adipocytes. Adipocyte lipid droplets represent key organelles coordinating lipid storage and mobilization in these cells. Recently, we identified the small GTPase, Rab34, in the lipid droplet proteome of adipocytes. Herein, we have characterized the distribution, intracellular transport, and potential contribution of this GTPase to adipocyte physiology and its regulation in obesity.

METHODS

3T3-L1 and human primary preadipocytes were differentiated in vitro and Rab34 distribution and trafficking were analyzed using markers of cellular compartments. 3T3-L1 adipocytes were transfected with expression vectors and/or Rab34 siRNA and assessed for secretory activity, lipid accumulation and expression of proteins regulating lipid metabolism. Proteomic and protein interaction analyses were employed for the identification of the Rab34 interactome. These studies were combined with functional analysis to unveil the role played by the GTPase in adipocytes, with a focus on the actions conveyed by Rab34 interacting proteins. Finally, Rab34 regulation in response to obesity was also evaluated.

RESULTS

Our results show that Rab34 localizes at the Golgi apparatus in preadipocytes. During lipid droplet biogenesis, Rab34 translocates from the Golgi to endoplasmic reticulum-related compartments and then reaches the surface of adipocyte lipid droplets. Rab34 exerts distinct functions related to its intracellular location. Thus, at the Golgi, Rab34 regulates cisternae integrity as well as adiponectin trafficking and oligomerization. At the lipid droplets, this GTPase controls lipid accumulation and lipolysis through its interaction with the E1-ubiquitin ligase, UBA1, which induces the ubiquitination and proteasomal degradation of the fatty acid transporter and member of Rab34 interactome, FABP5. Finally, Rab34 levels in the adipose tissue and adipocytes are regulated in response to obesity and related pathogenic insults (i.e., fibrosis).

CONCLUSIONS

Rab34 plays relevant roles during adipocyte differentiation, including from the regulation of the oligomerization (i.e., biological activity) and secretion of a major adipokine with insulin-sensitizing actions, adiponectin, to lipid storage and mobilization from lipid droplets. Rab34 dysregulation in obesity may contribute to the altered adipokine secretion and lipid metabolism that characterize adipocyte dysfunction in conditions of excess adiposity.

Elucidating the functional role of human ABHD16B lipase in regulating triacylglycerol mobilization and membrane lipid synthesis in Saccharomyces cerevisiae

Lipids are essential biological macromolecules that play a pivotal role in various physiological processes and cellular homeostasis. ABHD16B, a member of the α/β-hydrolase domain (ABHD) superfamily protein, has emerged as a potential key regulator in lipid metabolism. However, the precise role of human ABHD16B in lipid metabolism remains unclear. In this study, we reported the overexpression of ABHD16B in Saccharomyces cerevisiae to determine its physiological relevance in lipid metabolism. Through in vivo [14C]acetate labeling experiments, we observed that overexpression of ABHD16B causes a decrease in cellular triacylglycerol (TAG) levels and a concurrent increase in phospholipid synthesis in wild-type cells. Mass spectrometry (LC-MS/MS) analysis further corroborated these findings, showing a significant decrease in TAGs with a carbon chain length of 48 and an increase in major phospholipid species, specifically 34:2, upon overexpression of ABHD16B. Confocal microscopy analysis revealed a reduction in the number of lipid droplets in strains overexpressing ABHD16B, consistent with the observed decrease in neutral lipids. Additionally, qRT-PCR analysis indicated a high phospholipid synthetic activity of ABHD16B and a potential decrease in TAG levels in wild-type yeast, possibly due to upregulation of endogenous TAG hydrolytic enzymes, as confirmed using 3tglsΔ mutant strain. Furthermore, GC-MS analysis revealed significant modifications in fatty acid composition upon ABHD16B overexpression. Collectively, our results underscore the influence of ABHD16B overexpression on TAG levels, phospholipid synthesis, lipid droplet dynamics, and fatty acid composition. These findings reveal a complex interplay between TAG hydrolysis and phospholipid synthesis, highlighting the critical involvement of ABHD16B in lipid homeostasis and providing further insights into its regulatory function in cellular lipid metabolism.

Transcriptome analysis of norepinephrine-induced lipolysis in differentiated adipocytes of Bama pig

Sympathetic innervation of white adipose tissue (WAT) plays a key role in the regulation of lipid metabolism. Sympathetic activation promotes release of norepinephrine (NE), which binds to adrenergic receptors on adipocytes, promoting adipocyte lipolysis and enhanced oxidative metabolism. However, the mechanism by which sympathetic nerves regulate lipid metabolism in pig adipose tissue remains unclear. We used NE to simulate the process of sympathetic driving in pig adipocytes. RNA sequencing (RNA-seq) was used to determine the gene expression profile of pig adipocytes responding to NE stimulation. Our data suggests that the lipolytic signaling pathway is activated in pig adipocytes upon acute stimulation of NE, resulting in enhanced lipid metabolism and lipolysis, consistent with the phenomena found in humans and mice. Specifically, differentially expressed protein coding genes (PCGs) (SIRT4, SLC27A1) are mainly associated with functions that inhibit fatty acid oxidation and promote lipid synthesis. Similarly, we investigated the changes in regulatory transcripts such as long non-coding RNAs (lncRNAs) and transcripts of uncertain coding potential (TUCP) in response to NE and found that differentially expressed lncRNAs (lncG47338, lncG30660, lncG29516, lncG3790) and TUCP (TUCP_G38001) were co-expressed with target genes related to the promotion of fatty acid β-oxidation, lipolysis and oxidative metabolism, thus acting as regulators. These results indicate a broad suite of gene expression alterations in response to NE stimulation and promote the understanding of the molecular mechanisms by which NE regulates lipid metabolism in pigs.

Sex hormone-binding globulin improves lipid metabolism and reduces inflammation in subcutaneous adipose tissue of metabolic syndrome-affected horses

Equine metabolic syndrome (EMS) is a steadily growing endocrine disorder representing a real challenge in veterinary practice. As a multifactorial condition, EMS is characterized by three main metabolic abnormalities including insulin resistance, increased adiposity or obesity and hoof laminitis. Adipose tissue dysfunction is recognized as a core pathophysiological determinant of EMS, as it strongly participates to lipotoxicity and systemic metaflammation, both of which have been closely linked to the development of generalized insulin resistance. Besides, sex hormone binding globulin (SHBG) is an important sex steroids transporters that has been recently proposed as an important metabolic mediator. Therefore, the aim of this study was to verify whether SHBG treatment may ameliorate subcutaneous adipose tissue metabolic failure under EMS condition in terms of lipidome homeostasis, lipid metabolism programs, insulin signalling and local inflammation. Subcutaneous adipose tissue (SAT) biopsies were collected post-mortem from healthy (n = 3) and EMS (n = 3) slaughtered horses. SHBG protein has been applied to SAT samples from EMS horses for 24 h at a final concentration of 50 nM, while control groups (healthy and untreated EMS) were cultured in the presence of SHBG-vehicle only. Tissues from all groups were afterwards secured for downstream analysis of gene expression using RT-qPCR, protein levels by Western blot and ELISA assay and lipidomics through GC-MS technique. Obtained results showcased that SHBG intervention efficiently normalized the altered fatty acids (FAs) profiles by lowering the accumulation of saturated and trans FAs, as well as the pro-inflammatory arachidonic and linoleic acids. Moreover, SHBG showed promising value for the regulation of adipocyte lipolysis and engorgement by lowering the levels of perilipin-1. SHBG exerted moderated effect toward SCD1 and FASN enzymes expression, but increased the LPL abundance. Interestingly, SHBG exhibited a negative regulatory effect on pro-adipogenic stimulators and induced higher expression of KLF3, IRF3 and β-catenin, known as strong adipogenesis repressors. Finally, SHBG protein showed remarkable ability in restoring the insulin signal transduction, IR/IRS/Pi3K/AKT phosphorylation events and GLUT4 transporter abundance, and further attenuate pro-inflammatory response by lowering IL-6 tissue levels and targeting the PDIA3/ERK axis. Overall, the obtained data clearly demonstrate the benefice of SHBG treatment in the regulation of adipose tissue metabolism in the course of EMS and provide new insights for the development of molecular therapies with potential translational application to human metabolic disorders.

Foxk1 stimulates adipogenic differentiation via a peroxisome proliferator-activated receptor gamma 2-dependent mechanism

Adipogenesis is a tightly regulated process, and its dysfunction has been linked to metabolic disorders such as obesity. Forkhead box k1 (Foxk1) is known to play a role in the differentiation of myogenic precursor cells and tumorigenesis of different types of cancers; however, it is not clear whether and how it influences adipocyte differentiation. Here, we found that Foxk1 was induced in mouse primary bone marrow stromal cells (BMSCs) and established mesenchymal progenitor/stromal cell lines C3H/10T1/2 and ST2 after adipogenic treatment. In addition, obese db/db mice have higher Foxk1 expression in inguinal white adipose tissue than nonobese db/m mice. Foxk1 overexpression promoted adipogenic differentiation of C3H/10T1/2, ST2 cells and BMSCs, along with the enhanced expression of CCAAT/enhancer binding protein-α, peroxisome proliferator-activated receptor γ (Pparγ), and fatty acid binding protein 4. Moreover, Foxk1 overexpression enhanced the expression levels of lipogenic factors during adipogenic differentiation in both C3H/10T1/2 cells and BMSCs. Conversely, Foxk1 silencing impaired these cells from fully differentiating. Furthermore, adipogenic stimulation induced the nuclear translocation of Foxk1, which depended on the mTOR and PI3-kinase signaling pathways. Subsequently, Foxk1 is directly bound to the Pparγ2 promoter, stimulating its transcriptional activity and promoting adipocyte differentiation. Collectively, our study provides the first evidence that Foxk1 promotes adipocyte differentiation from progenitor cells by promoting nuclear translocation and upregulating the transcriptional activity of the Pparγ2 promoter during adipogenic differentiation.

Insulin signaling in development

Nutrient intake is obligatory for animal growth and development, but nutrients alone are not sufficient. Indeed, insulin and homologous hormones are required for normal growth even in the presence of nutrients. These hormones communicate nutrient status between organs, allowing animals to coordinate growth and metabolism with nutrient supply. Insulin and related hormones, such as insulin-like growth factors and insulin-like peptides, play important roles in development and metabolism, with defects in insulin production and signaling leading to hyperglycemia and diabetes. Here, we describe the insulin hormone family and the signal transduction pathways activated by these hormones. We highlight the roles of insulin signaling in coordinating maternal and fetal metabolism and growth during pregnancy, and we describe how secretion of insulin is regulated at different life stages. Additionally, we discuss the roles of insulin signaling in cell growth, stem cell proliferation and cell differentiation. We provide examples of the role of insulin in development across multiple model organisms: Caenorhabditis elegans, Drosophila, zebrafish, mouse and human.

Sulforaphane: A nutraceutical against diabetes-related complications

There is an increasing interest in the use of nutraceuticals and plant-derived bioactive compounds from foods for their potential health benefits. For example, as a major active ingredient found from cruciferous vegetables like broccoli, there has been growing interest in understanding the therapeutic effects of sulforaphane against diverse metabolic complications. The past decade has seen an extensive growth in literature reporting on the potential health benefits of sulforaphane to neutralize pathological consequences of oxidative stress and inflammation, which may be essential in protecting against diabetes-related complications. In fact, preclinical evidence summarized within this review supports an active role of sulforaphane in activating nuclear factor erythroid 2-related factor 2 or effectively modulating AMP-activated protein kinase to protect against diabetic complications, including diabetic cardiomyopathy, diabetic neuropathy, diabetic nephropathy, as well as other metabolic complications involving non-alcoholic fatty liver disease and skeletal muscle insulin resistance. With clinical evidence suggesting that foods rich in sulforaphane like broccoli can improve the metabolic status and lower cardiovascular disease risk by reducing biomarkers of oxidative stress and inflammation in patients with type 2 diabetes. This information remains essential in determining the therapeutic value of sulforaphane or its potential use as a nutraceutical to manage diabetes and its related complications. Finally, this review discusses essential information on the bioavailability profile of sulforaphane, while also covering information on the pathological consequences of oxidative stress and inflammation that drive the development and progression of diabetes.

Actinidia deliciosa Extract as a Promising Supplemental Agent for Hepatic and Renal Complication-Associated Type 2 Diabetes (In Vivo and In Silico-Based Studies)

Type 2 diabetes (T2D) is a chronic metabolic condition associated with obesity, oxidative stress-mediated inflammation, apoptosis, and impaired insulin signaling. The utilization of phytochemical therapy generated from plants has emerged as a promising approach for the treatment of diabetes and its complications. Kiwifruit is recognized for its substantial content of antioxidative phenolics. Therefore, this work aimed to examine the effect of Actinidia deliciosa (kiwi fruit) on hepatorenal damage in a high-fat diet (HFD) and streptozotocin (STZ)-induced T2D in rats using in vivo and in silico analyses. An increase in hepatic and renal lipid peroxidation was observed in diabetic rats accompanied by a decrease in antioxidant status. Furthermore, it is important to highlight that there were observable inflammatory and apoptotic responses in the hepatic and renal organs of rats with diabetes, along with a dysregulation of the phosphorylation levels of mammalian target of rapamycin (mTOR), protein kinase B (Akt), and phosphoinositide 3-kinase (PI3K) signaling proteins. However, the administration of kiwi extract to diabetic rats alleviated hepatorenal dysfunction, inflammatory processes, oxidative injury, and apoptotic events with activation of the insulin signaling pathway. Furthermore, molecular docking and dynamic simulation studies revealed quercetin, chlorogenic acid, and melezitose as components of kiwi extract that docked well with potential as effective natural products for activating the silent information regulator 1(SIRT-1) pathway. Furthermore, phenolic acids in kiwi extract, especially syringic acid, P-coumaric acid, caffeic acid, and ferulic acid, have the ability to inhibit the phosphatase and tensin homolog (PTEN) active site. In conclusion, it can be argued that kiwi extract may present a potentially beneficial adjunctive therapy approach for the treatment of diabetic hepatorenal complications.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

The impact of dietary fructose on gut permeability, microbiota, abdominal adiposity, insulin signaling and reproductive function

The excessive intake of fructose in the regular human diet could be related to global increases in metabolic disorders. Sugar-sweetened soft drinks, mostly consumed by children, adolescents, and young adults, are the main source of added fructose. Dietary high-fructose can increase intestinal permeability and circulatory endotoxin by changing the gut barrier function and microbial composition. Excess fructose transports to the liver and then triggers inflammation as well as de novo lipogenesis leading to hepatic steatosis. Fructose also induces fat deposition in adipose tissue by stimulating the expression of lipogenic genes, thus causing abdominal adiposity. Activation of the inflammatory pathway by fructose in target tissues is thought to contribute to the suppression of the insulin signaling pathway producing systemic insulin resistance. Moreover, there is some evidence that high intake of fructose negatively affects both male and female reproductive systems and may lead to infertility. This review addresses dietary high-fructose-induced deteriorations that are obvious, especially in gut permeability, microbiota, abdominal fat accumulation, insulin signaling, and reproductive function. The recognition of the detrimental effects of fructose and the development of relevant new public health policies are necessary in order to prevent diet-related metabolic disorders.

Obesity-induced changes in cancer cells and their microenvironment: Mechanisms and therapeutic perspectives to manage dysregulated lipid metabolism

Obesity has been closely related to cancer progression, recurrence, metastasis, and treatment resistance. We aim to review recent progress in the knowledge on the obese macroenvironment and the generated adipose tumor microenvironment (TME) inducing lipid metabolic dysregulation and their influence on carcinogenic processes. Visceral white adipose tissue expansion during obesity exerts systemic or macroenvironmental effects on tumor initiation, growth, and invasion by promoting inflammation, hyperinsulinemia, growth-factor release, and dyslipidemia. The dynamic relationship between cancer and stromal cells of the obese adipose TME is critical for cancer cell survival and proliferation as well. Experimental evidence shows that secreted paracrine signals from cancer cells can induce lipolysis in cancer-associated adipocytes, causing them to release free fatty acids and acquire a fibroblast-like phenotype. Such adipocyte delipidation and phenotypic change is accompanied by an increased secretion of cytokines by cancer-associated adipocytes and tumor-associated macrophages in the TME. Mechanistically, the availability of adipose TME free fatty acids and tumorigenic cytokines concomitant with the activation of angiogenic processes creates an environment that favors a shift in the cancer cells toward an aggressive phenotype associated with increased invasiveness. We conclude that restoring the aberrant metabolic alterations in the host macroenvironment and in adipose TME of obese subjects would be a therapeutic option to prevent cancer development. Several dietary, lipid-based, and oral antidiabetic pharmacological therapies could potentially prevent tumorigenic processes associated with the dysregulated lipid metabolism closely linked to obesity.

Associations of fatty acids composition and estimated desaturase activities in erythrocyte phospholipids with biochemical and clinical indicators of cardiometabolic risk in non-diabetic Serbian women: the role of level of adiposity

Introduction

Fatty acids (FAs) composition and desaturase activities can be altered in different metabolic conditions, but the adiposity-independent associations with clinical and biochemical indicators of cardiometabolic risk are still unclear. This study aimed to analyze the associations of FAs composition and estimated desaturase activities with anthropometric, clinical, and biochemical cardiometabolic risk indicators in non-diabetic Serbian women, and to investigate if these associations were independent of the level of adiposity and other confounders.

Methods

In 76 non-diabetic, otherwise healthy Serbian women, aged 24-68 years, with or without metabolic syndrome or obesity (BMI=23.6±5.6 kg/m2), FA composition in erythrocyte phospholipids was measured by gas-liquid chromatography. Desaturase activities were estimated from product/precursor FAs ratios (D9D:16:1n-7/16:0; D6D:20:3n-6/18:2n-6; D5D:20:4n-6/20:3n-6). Correlations were made with anthropometric, biochemical (serum glucose, triacylglycerols, LDL-C, HDL-C, ALT, AST, and their ratios) and clinical (blood pressure) indicators of cardiometabolic risk. Linear regression models were performed to test the independence of these associations.

Results

Estimated desaturase activities and certain FAs were associated with anthropometric, clinical and biochemical indicators of cardiometabolic risk: D9D, D6D, 16:1n-7 and 20:3n-6 were directly associated, while D5D and 18:0 were inversely associated. However, the associations with clinical and biochemical indicators were not independent of the associations with the level of adiposity, since they were lost after controlling for anthropometric indices. After controlling for multiple confounders (age, postmenopausal status, education, smoking, physical activity, dietary macronutrient intakes, use of supplements, alcohol consumption), the level of adiposity was the most significant predictor of desaturase activities and aforementioned FAs levels, and mediated their association with biochemical/clinical indicators. Vice versa, desaturase activities predicted the level of adiposity, but not other components of cardiometabolic risk (if the level of adiposity was accounted). While the associations of anthropometric indices with 16:1n-7, 20:3n-6, 18:0 and D9D and D6D activities were linear, the associations with D5D activity were the inverse U-shaped. The only adiposity-independent association of FAs profiles with the indicators of cardiometabolic risk was a positive association of 20:5n-3 with ALT/AST ratio, which requires further exploration.

Discussion

Additional studies are needed to explore the mechanisms of the observed associations.

Thyroid Hormone Receptor-β Agonists in NAFLD Therapy: Possibilities and Challenges

Nonalcoholic fatty liver disease (NAFLD) is a progressive metabolic liver disease with an unknown pathogenesis and no FDA-approved drug treatment to date. Hypothyroidism has been identified as a risk factor for NAFLD as thyroxine is required for regulating metabolism in adults. Thyroxine has been shown to reduce fat in the livers of murine models with experimentally induced NAFLD. The use of synthetic thyroxine has been shown to increase lipid metabolism leading to weight loss; however, thyroxine has also been shown to cause many side effects, especially in the heart. Overcoming these cardiac side effects involves designing agonists specific to one of the 2 gene subtypes for the thyroid hormone (TH) receptor (TR), TRβ. While the other TH receptor subtype, TRα, is mainly expressed in the heart and is responsible for thyroxine's cardiac function, TRβ is mainly expressed in the liver and is involved in liver function. Using TRβ-specific agonists to treat NAFLD can prevent cardiac and other adverse side effects. Several TRβ-specific agonists have shown positive therapeutic effects in NAFLD animal models and have entered clinical trials. We seek to provide a comprehensive updated reference of TRβ-specific agonists in this review and explore the future therapeutic potential of TRβ-specific activation in the treatment of NAFLD.

Acetyl-CoA carboxylase 1 is a suppressor of the adipocyte thermogenic program

Disruption of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) in mice induces browning in inguinal white adipose tissue (iWAT). However, adipocyte FASN knockout (KO) increases acetyl-coenzyme A (CoA) and malonyl-CoA in addition to depletion of palmitate. We explore which of these metabolite changes triggers adipose browning by generating eight adipose-selective KO mouse models with loss of ATP-citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), ACC2, malonyl-CoA decarboxylase (MCD) or FASN, or dual KOs ACLY/FASN, ACC1/FASN, and ACC2/FASN. Preventing elevation of acetyl-CoA and malonyl-CoA by depletion of adipocyte ACLY or ACC1 in combination with FASN KO does not block the browning of iWAT. Conversely, elevating malonyl-CoA levels in MCD KO mice does not induce browning. Strikingly, adipose ACC1 KO induces a strong iWAT thermogenic response similar to FASN KO while also blocking malonyl-CoA and palmitate synthesis. Thus, ACC1 and FASN are strong suppressors of adipocyte thermogenesis through promoting lipid synthesis rather than modulating the DNL intermediates acetyl-CoA or malonyl-CoA.

Body Fat Distribution, Fasting Insulin Levels, and Insulin Secretion: A Bidirectional Mendelian Randomization Study

CONTEXT

Hyperinsulinemia and adiposity are associated with one another, but the directionality of this relation is debated.

OBJECTIVE

Here, we tested the direction of the causal effects of fasting insulin (FI) levels and body fat accumulation/distribution using 2-sample bidirectional Mendelian randomization (MR).

METHODS

We included summary statistics from large-scale genome-wide association studies for body mass index (BMI, n = 806 834), waist to hip ratio adjusted for BMI (WHRadjBMI, n = 694 649), abdominal subcutaneous, visceral and gluteofemoral adipose tissue (n = 38 965), FI levels (n = 98 210), pancreatic islets gene expression (n = 420), and hypothalamus gene expression (n = 155). We used inverse variance-weighted and robust MR methods that relied on statistically and biologically driven genetic instruments.

RESULTS

Both BMI and WHRadjBMI were positively associated with FI. Results were consistent across all robust MR methods and when variants mapped to the hypothalamus (presumably associated with food behavior) were included. In multivariable MR analyses, when waist circumference and BMI were mutually adjusted, the direct effect of waist circumference on FI was 2.43 times larger than the effect of BMI on FI. FI was not associated with adiposity. By contrast, using genetic instruments mapped to gene expression in pancreatic islets (presumably more specific to insulin secretion), insulin was positively associated with BMI and abdominal subcutaneous and gluteofemoral adipose tissue, but not with visceral adipose tissue.

CONCLUSION

Although these results will need to be supported by experimental investigations, results of this MR study suggest that abdominal adiposity may be a key determinant of circulating insulin levels. Alternatively, insulin secretion may promote peripheral adipose tissue accumulation.

Dysregulation of Lipid and Glucose Metabolism in Nonalcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a highly prevalent condition affecting approximately a quarter of the global population. It is associated with increased morbidity, mortality, economic burden, and healthcare costs. The disease is characterized by the accumulation of lipids in the liver, known as steatosis, which can progress to more severe stages such as steatohepatitis, fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). This review focuses on the mechanisms that contribute to the development of diet-induced steatosis in an insulin-resistant liver. Specifically, it discusses the existing literature on carbon flux through glycolysis, ketogenesis, TCA (Tricarboxylic Acid Cycle), and fatty acid synthesis pathways in NAFLD, as well as the altered canonical insulin signaling and genetic predispositions that lead to the accumulation of diet-induced hepatic fat. Finally, the review discusses the current therapeutic efforts that aim to ameliorate various pathologies associated with NAFLD.

Brain insulin signaling suppresses lipolysis in the absence of peripheral insulin receptors and requires the MAPK pathway

OBJECTIVES

Insulin's ability to counterbalance catecholamine-induced lipolysis defines insulin action in adipose tissue. Insulin suppresses lipolysis directly at the level of the adipocyte and indirectly through signaling in the brain. Here, we further characterized the role of brain insulin signaling in regulating lipolysis and defined the intracellular insulin signaling pathway required for brain insulin to suppress lipolysis.

METHODS

We used hyperinsulinemic clamp studies coupled with tracer dilution techniques to assess insulin's ability to suppress lipolysis in two different mouse models with inducible insulin receptor depletion in all tissues (IR^ΔWB) or restricted to peripheral tissues excluding the brain (IR^ΔPER). To identify the underlying signaling pathway required for brain insulin to inhibit lipolysis, we continuously infused insulin +/- a PI3K or MAPK inhibitor into the mediobasal hypothalamus of male Sprague Dawley rats and assessed lipolysis during clamps.

RESULTS

Genetic insulin receptor deletion induced marked hyperglycemia and insulin resistance in both IR^ΔPER and IR^ΔWB mice. However, the ability of insulin to suppress lipolysis was largely preserved in IR^ΔPER, but completely obliterated in IR^ΔWB mice indicating that insulin is still able to suppress lipolysis as long as brain insulin receptors are present. Blocking the MAPK, but not the PI3K pathway impaired the inhibition of lipolysis by brain insulin signaling.

CONCLUSION

Brain insulin is required for insulin to suppress adipose tissue lipolysis and depends on intact hypothalamic MAPK signaling.

The adipocyte supersystem of insulin and cAMP signaling

Adipose tissue signals to brain, liver, and muscles to control whole body metabolism through secreted lipid and protein factors as well as neurotransmission, but the mechanisms involved are incompletely understood. Adipocytes sequester triglyceride (TG) in fed conditions stimulated by insulin, while in fasting catecholamines trigger TG hydrolysis, releasing glycerol and fatty acids (FAs). These antagonistic hormone actions result in part from insulin's ability to inhibit cAMP levels generated through such G-protein-coupled receptors as catecholamine-activated β-adrenergic receptors. Consistent with these antagonistic signaling modes, acute actions of catecholamines cause insulin resistance. Yet, paradoxically, chronically activating adipocytes by catecholamines cause increased glucose tolerance, as does insulin. Recent results have helped to unravel this conundrum by revealing enhanced complexities of these hormones' signaling networks, including identification of unexpected common signaling nodes between these canonically antagonistic hormones.

De novo lipogenesis fuels adipocyte autophagosome and lysosome membrane dynamics

Adipocytes robustly synthesize fatty acids (FA) from carbohydrate through the de novo lipogenesis (DNL) pathway, yet surprisingly DNL contributes little to their abundant triglyceride stored in lipid droplets. This conundrum raises the hypothesis that adipocyte DNL instead enables membrane expansions to occur in processes like autophagy, which requires an abundant supply of phospholipids. We report here that adipocyte Fasn deficiency in vitro and in vivo markedly impairs autophagy, evident by autophagosome accumulation and severely compromised degradation of the autophagic substrate p62. Our data indicate the impairment occurs at the level of autophagosome-lysosome fusion, and indeed, loss of Fasn decreases certain membrane phosphoinositides necessary for autophagosome and lysosome maturation and fusion. Autophagy dependence on FA produced by Fasn is not fully alleviated by exogenous FA in cultured adipocytes, and interestingly, imaging studies reveal that Fasn colocalizes with nascent autophagosomes. Together, our studies identify DNL as a critical source of FAs to fuel autophagosome and lysosome maturation and fusion in adipocytes.

Analysis of Metabolite Distribution in Rat Liver of High-Fat Model by Mass Spectrometry Imaging

Hyperlipidemia is a medical condition characterized by elevated levels of blood lipids, especially triglycerides (TG). However, it remains unclear whether TG levels remain consistently elevated throughout the entire developmental stage of the high-lipid state. In our animal experiment, we found that TG levels were significantly higher in the early stage of the high-lipid model but significantly decreased at the 14th week of the late stage, reaching levels similar to those of the control group. This suggests that TG levels in the high-lipid model are not always higher than those of the control group. To determine the reason for this observation, we used in situ mass spectrometry imaging (MSI) to detect the distribution of metabolites in the liver of rats. The metabolite distribution of the control rats at different stages was significantly different from that of the model rats, and the high-lipid model differed significantly from the control rats. We identified nine functional metabolites that showed differences throughout the period, namely, PA(20:3-OH/i-21:0), PA(20:4-OH/22:6), PG(20:5-OH/i-16:0), PG(22:6-2OH/i-13:0), PG(O-18:0/20:4), PGP(18:3-OH/i-12:0), PGP(PGJ2/i-15:0), SM(d18:0/18:1-2OH), and TG(14:0/14:0/16:0), among which TG was most significantly correlated with hyperlipidemia and high lipid. This study is unique in that it used MSI to reveal the changes in metabolites in situ, showing the distribution of different metabolites or the same metabolite in liver tissue. The findings highlight the importance of considering the animal’s age when using TG as a biomarker for hyperlipidemia. Additionally, the MSI images of the liver in the high-lipid model clearly indicated the distribution and differences of more significant metabolites, providing valuable data for further research into new biomarkers and mechanisms of hyperlipidemia. This new pathway of in situ, visualized, and data-rich metabolomics research provides a more comprehensive understanding of the characteristics of high lipid and its implications for disease prevention and treatment.

Neutralizing MIP3α Reduces Renal Immune Cell Infiltration and Progressive Renal Injury in Young Obese Dahl Salt-Sensitive Rats

Recently, we reported that the early progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats was associated with increased macrophage inflammatory protein 3-α (MIP3α) expression prior to puberty. Therefore, this study tested the hypothesis that MIP3α plays a role in recruiting immune cells, thereby triggering renal inflammation and early progressive renal injury in SSLepRmutant rats prior to puberty. Four-week-old Dahl salt-sensitive (SS) and SSLepRmutant rats either served as control (IgG; intraperitoneal, every other day) or received MIP3α-neutralizing antibody (MNA; 100 µg/kg) for 4 weeks. MNA reduced circulating and renal MIP3α levels and proinflammatory immune cells by 50%. Although MNA treatment did not affect blood glucose and plasma cholesterol levels, MNA markedly decreased insulin resistance and triglyceride levels in SSLepRmutant rats. We observed no differences in mean arterial pressure (MAP) between SS and SSLepRmutant rats, and MNA had no effect on MAP in either strain. Proteinuria was significantly increased in SSLepRmutant rats versus SS rats over the course of the study. Treatment with MNA markedly decreased proteinuria in SSLepRmutant rats while not affecting SS rats. Also, MNA decreased glomerular and tubular injury and renal fibrosis in SSLepRmutant rats while not affecting SS rats. Overall, these data indicate that MIP3α plays an important role in renal inflammation during the early progression of renal injury in obese SSLepRmutant rats prior to puberty. These data also suggest that MIP3α may be a novel therapeutic target to inhibit insulin resistance and prevent progressive proteinuria in obese children. SIGNIFICANCE STATEMENT: Childhood obesity is increasing at an alarming rate and is now being associated with renal disease. Although most studies have focused on the mechanisms of renal injury associated with adult obesity, few studies have examined the mechanisms of renal injury involved during childhood obesity. In the current study, we observed that the progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant rats was associated with an increase in MIP3α, a chemokine, before puberty, and inhibition of MIP3α markedly reduced renal injury.

Adipocyte-derived extracellular vesicles increase insulin secretion through transport of insulinotropic protein cargo

Adipocyte-derived extracellular vesicles (AdEVs) are membranous nanoparticles that convey communication from adipose tissue to other organs. Here, to delineate their role as messengers with glucoregulatory nature, we paired fluorescence AdEV-tracing and SILAC-labeling with (phospho)proteomics, and revealed that AdEVs transfer functional insulinotropic protein cargo into pancreatic β-cells. Upon transfer, AdEV proteins were subjects for phosphorylation, augmented insulinotropic GPCR/cAMP/PKA signaling by increasing total protein abundances and phosphosite dynamics, and ultimately enhanced 1st-phase glucose-stimulated insulin secretion (GSIS) in murine islets. Notably, insulinotropic effects were restricted to AdEVs isolated from obese and insulin resistant, but not lean mice, which was consistent with differential protein loads and AdEV luminal morphologies. Likewise, in vivo pre-treatment with AdEVs from obese but not lean mice amplified insulin secretion and glucose tolerance in mice. This data suggests that secreted AdEVs can inform pancreatic β-cells about insulin resistance in adipose tissue in order to amplify GSIS in times of increased insulin demand.

Neonatal hyperoxia induces activated pulmonary cellular states and sex-dependent transcriptomic changes in a model of experimental bronchopulmonary dysplasia

Hyperoxia disrupts lung development in mice and causes bronchopulmonary dysplasia (BPD) in neonates. To investigate sex-dependent molecular and cellular programming involved in hyperoxia, we surveyed the mouse lung using single cell RNA sequencing (scRNA-seq), and validated our findings in human neonatal lung cells in vitro. Hyperoxia-induced inflammation in alveolar type (AT) 2 cells gave rise to damage-associated transient progenitors (DATPs). It also induced a new subpopulation of AT1 cells with reduced expression of growth factors normally secreted by AT1 cells, but increased mitochondrial gene expression. Female alveolar epithelial cells had less EMT and pulmonary fibrosis signaling in hyperoxia. In the endothelium, expansion of Car4+ EC (Cap2) was seen in hyperoxia along with an emergent subpopulation of Cap2 with repressed VEGF signaling. This regenerative response was increased in females exposed to hyperoxia. Mesenchymal cells had inflammatory signatures in hyperoxia, with a new distal interstitial fibroblast subcluster characterized by repressed lipid biosynthesis and a transcriptomic signature resembling myofibroblasts. Hyperoxia-induced gene expression signatures in human neonatal fibroblasts and alveolar epithelial cells in vitro resembled mouse scRNA-seq data. These findings suggest that neonatal exposure to hyperoxia programs distinct sex-specific stem cell progenitor and cellular reparative responses that underpin lung remodeling in BPD.

Caveolin-2 in association with nuclear lamina controls adipocyte hypertrophy

Here, we identify that Caveolin-2 (Cav-2), an integral membrane protein, controls adipocyte hypertrophy in association with nuclear lamina. In the hypertrophy stage of adipogenesis, pY19-Cav-2 association with lamin A/C facilitated the disengagement of CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) from lamin A/C and repressed Cav-2 promoter at the nuclear periphery for epigenetic activation of Cav-2, and thereby promoted C/EBPα and PPARγ-induced adipocyte hypertrophy. Stable expression of Cav-2 was required and retained by phosphorylation, deubiquitination, and association with lamin A/C for the adipocyte hypertrophy. However, obese adipocytes exhibited augmented Cav-2 stability resulting from the up-regulation of lamin A/C over lamin B1, protein tyrosine phosphatase 1B (PTP1B), and nuclear deubiquitinating enzyme (DUB), Uchl5. Our findings show a novel epigenetic regulatory mechanism of adipocyte hypertrophy by Cav-2 at the nuclear periphery.

Lipidomics in gestational diabetes mellitus

PURPOSE OF REVIEW

Epidemiological and mechanistic studies have reported relationships between blood lipids, mostly measured by traditional method in clinical settings, and gestational diabetes mellitus (GDM). Recent advances of high-throughput lipidomics techniques have made available more comprehensive lipid profiling in biological samples. This review aims to summarize evidence from prospective studies in assessing relations between blood lipids and GDM, and discuss potential underlying mechanisms.

RECENT FINDINGS

Mass spectrometry and nuclear magnetic resonance spectroscopy-based analytical platforms are extensively used in lipidomics research. Epidemiological studies have identified multiple novel lipidomic biomarkers that are associated with risk of GDM, such as certain types of fatty acids, glycerolipids, glycerophospholipids, sphingolipids, cholesterol, and lipoproteins. However, the findings are inconclusive mainly due to the heterogeneities in study populations, sample sizes, and analytical platforms. Mechanistic evidence indicates that abnormal lipid metabolism may be involved in the pathogenesis of GDM by impairing pancreatic β-cells and inducing insulin resistance through several etiologic pathways, such as inflammation and oxidative stress.

SUMMARY

Lipidomics is a powerful tool to study pathogenesis and biomarkers for GDM. Lipidomic biomarkers and pathways could help to identify women at high risk for GDM and could be potential targets for early prevention and intervention of GDM.

Ankle fusion with tibiotalocalcaneal retrograde nail for fragility ankle fractures: outcomes at a major trauma centre

PURPOSE

Fragility ankles fractures in the geriatric population are challenging to manage, due to fracture instability, soft tissue compromise, and patient co-morbidities. Traditional management options include open reduction internal fixation, or conservative treatment, both of which are fraught with high complication rates. We aimed to present functional outcomes of elderly patients with fragility ankle fractures treated with retrograde ankle fusion nails.

METHODS

A retrospective observational study was performed on patients who underwent intramedullary nailing with a tibiotalocalcaneal nail. Twenty patients met the inclusion criteria of being over sixty and having multiple co-morbidities. Patient demographics, AO/OTA fracture classification, intra-operative and post-operative complications, time to mobilisation and union, AOFAS and Olerud-Molander scores, and patient mobility were recorded.

RESULTS

There were seven males and thirteen females, with a mean age of 77.82 years old, five of whom are type 2 diabetics. Thirteen patients returned to their pre-operative mobility state, and the average Charlson Co-morbidity Index (CCI) was 5.05. Patients with a low CCI are more likely to return to pre-operative mobility status (p = 0.16; OR = 4.00). All patients achieved radiographical union, taking on average between 92.5 days and 144.6 days. The mean post-operative AOFAS and Olerud-Molander scores were 53.0 and 50.9, respectively. There were four cases of superficial infection, four cases of broken or loose distal locking screws. There were no deep infections, periprosthetic fractures, nail breakages, or non-unions.

CONCLUSION

Tibiotalocalcaneal nailing is an effective and safe option for managing unstable ankle fractures in the elderly. This technique leads to lower complication rates and earlier mobilisation than traditional fixation methods.

Association of maternal lipid levels with birth weight and cord blood insulin: a Bayesian network analysis

OBJECTIVE

To assess the independent association of maternal lipid levels with birth weight and cord blood insulin (CBI) level.

SETTING

The Born in Guangzhou Cohort Study, Guangzhou, China.

PARTICIPANTS

Women who delivered between January 2015 and June 2016 and with umbilical cord blood retained were eligible for this study. Those with prepregnancy health conditions, without an available fasting blood sample in the second trimester, or without demographic and glycaemic information were excluded. After random selection, data from 1522 mother-child pairs were used in this study.

EXPOSURES AND OUTCOME MEASURES

Additive Bayesian network analysis was used to investigate the interdependency of lipid profiles with other metabolic risk factors (prepregnancy body mass index (BMI), fasting glucose and early gestational weight gain) in association with birth weight and CBI, along with multivariable linear regression models.

RESULTS

In multivariable linear regressions, maternal triglyceride was associated with increased birth weight (adjusted β=67.46, 95% CI 41.85 to 93.06 g per mmol/L) and CBI (adjusted β=0.89, 95% CI 0.06 to 1.72 μU/mL per mmol/L increase), while high-density lipoprotein cholesterol was associated with decreased birth weight (adjusted β=-45.29, 95% CI -85.49 to -5.09 g per mmol/L). After considering the interdependency of maternal metabolic risk factors in the Network analysis, none of the maternal lipid profiles was independently associated with birth weight and CBI. Instead, prepregnancy BMI was the global strongest factor for birth weight and CBI directly and indirectly.

CONCLUSIONS

Gestational dyslipidaemia appears to be secondary to metabolic dysfunction with no clear association with metabolic adverse outcomes in neonates. Maternal prepregnancy overweight/obesity appears the most influential upstream metabolic risk factor for both maternal and neonatal metabolic health; these data imply weight management may need to be addressed from the preconception period and during early pregnancy.

Plasma PFOA and PFOS Levels, DNA Methylation, and Blood Lipid Levels: A Pilot Study

Exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) is associated with blood lipids in adults, but the underlying mechanisms remain unclear. This pilot study aimed to investigate the associations between PFOA or PFOS and epigenome-wide DNA methylation and assess the mediating effect of DNA methylation on the PFOA/PFOS-blood lipid association. We measured plasma PFOA/PFOS and leukocyte DNA methylation in 98 patients enrolled from the hospital between October 2018 and August 2019. The median plasma PFOA/PFOS levels were 0.85 and 2.29 ng/mL. Plasma PFOA and PFOS levels were significantly associated with elevated total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels. There were 63/87 CpG positions and 8/11 differentially methylated regions (DMRs) associated with plasma PFOA/PFOS levels, respectively. In addition, 5 CpG positions (annotated to AFF3, CREB5, NRG2, USF2, and intergenic region) and one DMR annotated to IRF6 may mediate the association between plasma PFOA/PFOS and LDL levels (mediated proportion from 7.29 to 46.77%); two CpG positions may mediate the association between plasma PFOA/PFOS and TC levels (annotated to CREB5 and USF2, mediated proportion is around 30%). The data suggest that PFOA/PFOS exposure alters DNA methylation. More importantly, the association of PFOA/PFOS with lipid indicators was partly mediated by DNA methylation changes in lipid metabolism-related genes.

Dysfunction of insulin-AKT-UCP1 signalling inhibits transdifferentiation of human and mouse white preadipocytes into brown-like adipocytes

The mechanism of insulin signaling on browning of white preadipocytes remains unclear. Human and mouse primary subcutaneous white preadipocytes (hsASCs and WT lean and obese msASCs, respectively) were induced to transdifferentiate into beige adipocytes under conditions of intact or blocked insulin signaling, respectively. Level of phosphoinositide-3-kinase (PI3K) after induction of beige adipocytes under conditions of normal insulin signaling, phosphorylated protein kinase B (pAKT), peroxisome proliferator-activated receptor γ coactivator-1 alpha (PGC-1α), zinc-fifinger transcriptional factor PRD1-BF1-RIZ1 homologous domain-containing protein 16 (PRDM16), uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein beta (C/EBPβ) were significantly increased. Conversely, when insulin signaling is incompletely inhibited, the expression of the thermogenic and adipogenic factors is significantly reduced, with obvious impairment of adipogenesis. However, phosphorylation level of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and expression level of sirtuin type 1 (SIRT1) had increased. These white preadipocytes from different donors showed similar dynamic change in morphology and molecular levels during the browning. The present data indicate that insulin signaling plays a important role in regulation of browning of hsASCs and msASCs through PI3K-AKT-UCP1 signaling pathway. The insulin-AMPK-SIRT1 pathway was also involved in the adipocytes browning, while its effect is limited.

Systemic LSD1 Inhibition Prevents Aberrant Remodeling of Metabolism in Obesity

The transition from lean to obese states involves systemic metabolic remodeling that impacts insulin sensitivity, lipid partitioning, inflammation, and glycemic control. Here, we have taken a pharmacological approach to test the role of a nutrient-regulated chromatin modifier, lysine-specific demethylase (LSD1), in obesity-associated metabolic reprogramming. We show that systemic administration of an LSD1 inhibitor (GSK-LSD1) reduces food intake and body weight, ameliorates nonalcoholic fatty liver disease (NAFLD), and improves insulin sensitivity and glycemic control in mouse models of obesity. GSK-LSD1 has little effect on systemic metabolism of lean mice, suggesting that LSD1 has a context-dependent role in promoting maladaptive changes in obesity. In analysis of insulin target tissues we identified white adipose tissue as the major site of insulin sensitization by GSK-LSD1, where it reduces adipocyte inflammation and lipolysis. We demonstrate that GSK-LSD1 reverses NAFLD in a non-hepatocyte-autonomous manner, suggesting an indirect mechanism potentially via inhibition of adipocyte lipolysis and subsequent effects on lipid partitioning. Pair-feeding experiments further revealed that effects of GSK-LSD1 on hyperglycemia and NAFLD are not a consequence of reduced food intake and weight loss. These findings suggest that targeting LSD1 could be a strategy for treatment of obesity and its associated complications including type 2 diabetes and NAFLD.

Important Hormones Regulating Lipid Metabolism

There is a wide variety of kinds of lipids, and complex structures which determine the diversity and complexity of their functions. With the basic characteristic of water insolubility, lipid molecules are independent of the genetic information composed by genes to proteins, which determine the particularity of lipids in the human body, with water as the basic environment and genes to proteins as the genetic system. In this review, we have summarized the current landscape on hormone regulation of lipid metabolism. After the well-studied PI3K-AKT pathway, insulin affects fat synthesis by controlling the activity and production of various transcription factors. New mechanisms of thyroid hormone regulation are discussed, receptor α and β may mediate different procedures, the effect of thyroid hormone on mitochondria provides a new insight for hormones regulating lipid metabolism. Physiological concentration of adrenaline induces the expression of extrapituitary prolactin in adipose tissue macrophages, which promotes fat weight loss. Manipulation of hormonal action has the potential to offer a new therapeutic horizon for the global burden of obesity and its associated complications such as morbidity and mortality.

BMI and lipidomic biomarkers with risk of gestational diabetes in pregnant women

OBJECTIVE

The study aimed to identify BMI-related lipids and to explore the role of lipids linking BMI and gestational diabetes mellitus (GDM).

METHODS

Plasma lipidome, height, and weight were measured in early pregnancy among 1008 women. Pearson correlation analyses and least absolute shrinkage and selection operator regression (LASSO) were performed to identify BMI-associated lipids. Based on these lipids, a lipid score was created using LASSO, and its association with GDM risk was evaluated by conditional logistic regression. The causal relationships between BMI and lipids were tested by Mendelian randomization analysis with genotyping data. Mediation analysis was conducted to evaluate the mediating effect of lipids on the association of BMI with GDM.

RESULTS

Of 366 measured lipids, BMI was correlated with 28 lipids, which mainly belong to glycerophospholipids and glycerolipids. A total of 10 lipid species were associated with BMI, and a lipid score was established. A causal relationship between BMI and lysophosphatidylcholine 14:0 was observed. The lipid score was associated with a 1.69-fold increased risk of GDM per 1-point increment (95% CI: 1.33-2.15). Furthermore, BMI-associated lipids might explain 66.4% of the relationship between BMI and GDM.

CONCLUSIONS

Higher BMI in early pregnancy was associated with altered lipid metabolism that may contribute to the increased risk of GDM.

The Data Behind Popular Diets for Weight Loss

Both scientific evidence and popular diet trends have sought to identify the ideal diet for weight loss with strategies focused on either restricting carbohydrates or fat. While there is a strong physiologic rationale for either carbohydrate restriction or fat restriction to achieve a calorie deficit needed for weight loss, evidence from randomized controlled trials suggest either type of diet is effective for weight loss. The level of adherence, rather than macronutrient content, is the driver of successful weight loss.

Derhamnosylmaysin Inhibits Adipogenesis via Inhibiting Expression of PPARγ and C/EBPα in 3T3-L1 Cells

We investigated the effects of derhamnosylmaysin (DM) on adipogenesis and lipid accumulation in 3T3-L1 adipocytes. Our data showed that DM inhibited lipid accumulation and adipocyte differentiation in 3T3-L1 cells. Treatment of 3T3-L1 adipocytes with DM decreased the expression of major transcription factors, such as sterol regulatory element-binding protein-1c (SREBP-1c), the CCAAT-enhancer-binding protein (CEBP) family, and peroxisome proliferator-activated receptor gamma (PPARγ), in the regulation of adipocyte differentiation. Moreover, the expression of their downstream target genes related to adipogenesis and lipogenesis, including adipocyte fatty acid-binding protein (aP2), lipoprotein lipase (LPL), stearyl-CoA-desaturase-1 (SCD-1), acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS), was also decreased by treatment with DM during adipogenesis. Additionally, DM attenuated insulin-stimulated phosphorylation of Akt. These results first demonstrated that DM inhibited adipogenesis and lipogenesis through downregulation of the key adipogenic transcription factors SREBP-1c, the CEBP family, and PPARγ and inactivation of the major adipogenesis signaling factor Akt, which is intermediated in insulin. These studies demonstrated that DM is a new bioactive compound for antiadipogenic reagents for controlling overweight and obesity.

Dietary and lifestyle indices for hyperinsulinemia with the risk of obesity phenotypes: a prospective cohort study among Iranian adult population

Background

Previous studies have cited insulin-related disorders, including hyperinsulinemia, as one of the main causes of obesity risk and metabolic disorders. We aimed to investigate the association of the Empirical Dietary Index for Hyperinsulinemia (EDIH) and Empirical Lifestyle Index for Hyperinsulinemia (ELIH) with the risk of obesity phenotypes among Iranian adults.

Methods

Present study was conducted on 2705 subjects, including 1604 metabolically healthy normal weights (MHNW) and 1101 metabolically healthy obesity (MHO) individuals. Obesity phenotypes, including MHNW, MHO, metabolically unhealthy normal weights (MUNW), and metabolic unhealthy obesity (MUO), were determined using the criteria of the Joint International statement (JIS) for metabolic syndrome. Dietary intake data from the previous year was gathered using a food frequency questionnaire. Cox proportional hazard regression was used to estimate the hazard ratio and 95% confidence intervals (HRs and 95% CIs) of obesity phenotypes incident across tertiles of EDIH and ELIH scores.

Results

The mean ± SD of age and BMI of all participants were 33.5 ± 12.2 years and 24.3 ± 3.8 kg/m², respectively. In the multivariable-adjusted model, a higher ELIH score was associated with a greater risk for incidence of MUO (HR: 3.47, 95%CI: 2.54–4.74; P_trend =  < 0.001) and MHO (HR: 3.61, 95%CI: 2.73–4.77; P_trend =  < 0.001). Also, a higher score of EDIH was related to an increased risk of MUO incidence (HR: 1.35, 95%CI: 1.02–1.79; P for trend = 0.046). However, there was no significant association between a higher score of EDIH and the risk of MHO.

Conclusion

Our findings revealed that a high insulinemic potential of diet and lifestyle, determined by EDIH and ELIH indices, may be related to an increase in the simultaneous occurrence of obesity with metabolic disorders in Iranian adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13401-8.

Adipose Tissue Secretion Pattern Influences β-Cell Wellness in the Transition from Obesity to Type 2 Diabetes

The dysregulation of the β-cell functional mass, which is a reduction in the number of β-cells and their ability to secure adequate insulin secretion, represents a key mechanistic factor leading to the onset of type 2 diabetes (T2D). Obesity is recognised as a leading cause of β-cell loss and dysfunction and a risk factor for T2D. The natural history of β-cell failure in obesity-induced T2D can be divided into three steps: (1) β-cell compensatory hyperplasia and insulin hypersecretion, (2) insulin secretory dysfunction, and (3) loss of β-cell mass. Adipose tissue (AT) secretes many hormones/cytokines (adipokines) and fatty acids that can directly influence β-cell function and viability. As this secretory pattern is altered in obese and diabetic patients, it is expected that the cross-talk between AT and pancreatic β-cells could drive the maintenance of the β-cell integrity under physiological conditions and contribute to the reduction in the β-cell functional mass in a dysmetabolic state. In the current review, we summarise the evidence of the ability of the AT secretome to influence each step of β-cell failure, and attempt to draw a timeline of the alterations in the adipokine secretion pattern in the transition from obesity to T2D that reflects the progressive deterioration of the β-cell functional mass.

Using GPCRs as Molecular Beacons to Target Ovarian Cancer with Nanomedicines

The five-year survival rate for women with ovarian cancer is very poor despite radical cytoreductive surgery and chemotherapy. Although most patients initially respond to platinum-based chemotherapy, the majority experience recurrence and ultimately develop chemoresistance, resulting in fatal outcomes. The current administration of cytotoxic compounds is hampered by dose-limiting severe adverse effects. There is an unmet clinical need for targeted drug delivery systems that transport chemotherapeutics selectively to tumor cells while minimizing off-target toxicity. G protein-coupled receptors (GPCRs) are the largest family of membrane receptors, and many are overexpressed in solid tumors, including ovarian cancer. This review summarizes the progress in engineered nanoparticle research for drug delivery for ovarian cancer and discusses the potential use of GPCRs as molecular entry points to deliver anti-cancer compounds into ovarian cancer cells. A newly emerging treatment paradigm could be the personalized design of nanomedicines on a case-by-case basis.

Glycerol-3-phosphate phosphatase operates a glycerol shunt in pancreatic β-cells that controls insulin secretion and metabolic stress

Objective

The recently identified glycerol-3-phosphate (Gro3P) phosphatase (G3PP) in mammalian cells, encoded by the PGP gene, was shown to regulate glucose, lipid and energy metabolism by hydrolyzing Gro3P and to control glucose-stimulated insulin secretion (GSIS) in β-cells, in vitro. However, whether G3PP regulates β-cell function and insulin secretion in vivo is not known.

Methods

We now examined the role of G3PP in the control of insulin secretion in vivo, β-cell function and glucotoxicity in inducible β-cell specific G3PP-KO (BKO) mice. Inducible BKO mice were generated by crossing floxed-G3PP mice with Mip-Cre-ERT (MCre) mice. All the in vivo studies were done using BKO and control mice fed normal diet and the ex vivo studies were done using pancreatic islets from these mice.

Results

BKO mice, compared to MCre controls, showed increased body weight, adiposity, fed insulinemia, enhanced in vivo GSIS, reduced plasma triglycerides and mild glucose intolerance. Isolated BKO mouse islets incubated at high (16.7 mM), but not at low or intermediate glucose (3 and 8 mM), showed elevated GSIS, Gro3P content as well as increased levels of metabolites and signaling coupling factors known to reflect β-cell activation for insulin secretion. BKO islets also showed reduced glycerol release and increased O₂ consumption and ATP production at high glucose only. BKO islets chronically exposed to elevated glucose levels showed increased apoptosis, reduced insulin content and decreased mRNA expression of β-cell differentiation markers, Pdx-1, MafA and Ins-2.

Conclusions

The results demonstrate that β-cells are endowed with a “glycerol shunt”, operated by G3PP that regulates β-cell metabolism, signaling and insulin secretion in vivo, primarily at elevated glucose concentrations. We propose that the glycerol shunt plays a role in preventing insulin hypersecretion and excess body weight gain and contributes to β-cell mass preservation in the face of hyperglycemia.

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G3PP operates a glycerol shunt in β-cells to remove excess glucose as glycerol.

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Inducible β-cell specific G3PP-KO (BKO) mice show hyperinsulinemia.

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BKO mice show enhanced body weight and glucose induced insulin secretion.

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BKO isolated islets show elevated insulin secretion only at high glucose.

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Chronic exposure of BKO isolated islets to high glucose enhances glucotoxicity.

Water extract of Ferula lehmanni Boiss. prevents high-fat diet-induced overweight and liver injury by modulating the intestinal microbiota in mice

Obesity, often accompanied by hepatic steatosis, has been associated with an increased risk of health complications such as fatty liver disease and certain cancers. Ferula lehmannii Boiss., a food and medicine homologue, has been used for centuries as a seasoning showing anti-bacterial and anti-oxidant effects on digestive discomfort. In the present study, we sought to investigate whether a short-term oral administration of water extract of Ferula lehmanni Boiss. (WEFL) could prevent high-fat diet (HFD)-induced abnormal weight gain and hepatic steatosis in mice and its underlying mechanisms. WEFL reduced HFD-increased body weight, liver injury markers and inflammatory cytokines (i.e. IL-6 and IL-1β), and inhibited the elevation of AMPKα, SREBP-1c and FAS in HFD. Moreover, WEFL reconstructed the gut microbiota composition by increasing the relative abundances of beneficial bacteria, e.g. Akkermansia spp., while decreasing Desulfovibrio spp. and so on, thereby reversing the detrimental effects of HFD in mice. Removal of the gut microbiota with antibiotics partially eliminated the hepatoprotective effects of WEFL. Notably, WEFL substantially promoted the levels of short-chain fatty acids, especially butyric acid. To clarify the functional components at play in WEFL, we used UPLC-MS/MS to comprehensively detect its substance composition and found it to be a collection of polyphenol-rich compounds. Together, our findings demonstrate that WEFL prevented HFD-induced obesity and liver injury through the hepatic-microbiota axis, and such health-promoting value might be explained by the enriched abundant polyphenols.

Metabolic Risk Factors in Young Men With Healthy Body Fat But Different Level of Physical Activity

The study was performed to evaluate metabolic risk in young lean individuals characterized by different physical activity. A total of 194 students (93 active with 5–7 h weekly physical activity and 101 inactive) were accepted for the study. The following percentages of body fat were accepted as characteristic for lean men: 14% to 17% in active and 18% to 24% in inactive participants. Circulating glucose, insulin, triacylglycerols (TG), total cholesterol (TC), and high-dendity lipoprotein (HDL)-cholesterol (HDL-C) were assayed. Daily intake of energy and macronutrients was briefly assessed from 24 h food records collected over 4 days preceding blood collection. Insulin and TG differed with respect to physical activity and was lower by 37.5% and 12.5%, respectively, in active versus inactive participants. In active students with upper quartile of body fat percentage, the only significant difference was found between circulating insulin (by 28%, p < .04). In inactive participants with upper quartile of body fat, significant differences were found between levels of insulin and TG (by 25% and by 37.5%, respectively). Diet composition did not differ with respect to the percentage of energy derived from protein, fat, and carbohydrates. An inverse association between insulin level and the percentage of body fat seems to be physiological one because it has been noted in both active and inactive individuals. On the contrary, elevation in circulating TG found exclusively in inactive subjects seems to be secondary to the changes in adiposity and circulating insulin and is followed by tendency to higher levels of TC.

A randomized clinical trial evaluating the effect of empagliflozin on triglycerides in obese adults: Role of visceral fat

Background

Empagliflozin, a sodium glucose cotransporter 2 inhibitor, is a medication to treat type 2 diabetes. The effect of empagliflozin in persons without diabetes has received less attention. Here we conducted a randomized, double-blind placebo-controlled clinical trial to examine the effect of empagliflozin on plasma triglycerides in obese non-diabetic adults.

Methods

Participants (n = 35; BMI ≥ 30 kg/m²) underwent body composition assessments using MRI, and were randomly assigned to either placebo or empagliflozin (10 mg/d) for three months. At the baseline and post-treatment visit, after an overnight fast, blood was drawn for biochemical analysis. Participants received [U–¹³C₃]glycerol orally followed by multiple blood draws over 3 h to examine glycerol incorporation into triglycerides using NMR spectroscopy.

Results

The changes in blood triglyceride concentration with empagliflozin therapy related to the mass of baseline visceral adipose tissue (VAT; r = 0.53, p = 0.04). Empagliflozin slightly lowered triglycerides in obese subjects with low VAT, but increased triglycerides in the subjects with high VAT. Consistently, empagliflozin effectively suppressed triglyceride synthesis following [U–¹³C₃]glycerol administration in the subjects with low VAT (p < 0.05), but not in the subjects with high VAT. The subjects with high VAT lost body weight after three months of empagliflozin treatment. In all subjects, about 20% of the triglyceride backbone originated from mitochondrial metabolism of glycerol.

Conclusions

The effect of empagliflozin on triglycerides in obese adults differed depending on VAT. Empagliflozin suppressed triglyceride synthesis in the subjects with low VAT, but tended to increase triglycerides in those with high VAT.

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Visceral fat modulates the effect of empagliflozin on triglycerides in obese adults.

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Empagliflozin suppresses triglyceride synthesis in obese adults with low visceral fat.

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Empagliflozin tends to increase triglycerides in obese adults with high visceral fat.

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Empagliflozin induces weight loss in obese adults with high visceral fat.