Chronic Adipose Tissue Inflammation Linking Obesity to Insulin Resistance and Type 2 Diabetes

The lipidomic and inflammatory profiles of visceral and subcutaneous adipose tissues are distinctly regulated by the SGLT2 inhibitor empagliflozin in Zucker diabetic fatty rats

The pharmacological inhibition of sodium-glucose cotransporter 2 (SGLT2) has emerged as a treatment for patients with type 2 diabetes mellitus (T2DM), cardiovascular disease and/or other metabolic disturbances, although some of the mechanisms implicated in their beneficial effects are unknown. The SGLT2 inhibitor (SGLT2i) empagliflozin has been suggested as a regulator of adiposity, energy metabolism, and systemic inflammation in adipose tissue. The aim of our study was to evaluate the impact of a 6-week-empagliflozin treatment on the lipidome of visceral (VAT) and subcutaneous adipose tissue (SAT) from diabetic obese Zucker Diabetic Fatty (ZDF) rats using an untargeted metabolomics approach. We found that empagliflozin increases the content of diglycerides and oxidized fatty acids (FA) in VAT, while in SAT, it decreases the levels of several lysophospholipids and increases 2 phosphatidylcholines. Empagliflozin also reduces the expression of the cytokines interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNFα), monocyte-chemotactic protein-1 (MCP-1) and IL-10, and of Cd86 and Cd163 M1 and M2 macrophage markers in VAT, with no changes in SAT, except for a decrease in IL-1β. Empagliflozin treatment also shows an effect on lipolysis increasing the expression of hormone-sensitive lipase (HSL) in SAT and VAT and of adipose triglyceride lipase (ATGL) in VAT, together with a decrease in the adipose content of the FA transporter cluster of differentiation 36 (CD36). In conclusion, our data highlighted differences in the VAT and SAT lipidomes, inflammatory profiles and lipolytic function, which suggest a distinct metabolism of these two white adipose tissue depots after the empagliflozin treatment.

Interleukin-4 reduces insulin secretion in human islets from healthy but not type-2 diabetic donors

Type 2 diabetes (T2D) is associated with low-grade inflammation. Here we investigate if the anti-inflammatory cytokine interleukin-4 (IL-4) affects glucose-stimulated insulin secretion (GSIS) in human islets from non-diabetic (ND) and type-2 diabetic (T2D) donors. We first confirmed that GSIS is reduced in islets from T2D donors. Treatment with IL-4 for 48 h had no further effect on GSIS in these islets but significantly reduced secretion in ND islets. Acute treatment with IL-4 for 1 h had no effect on GSIS in ND islets which led us to suspect that IL-4 affects a slow cellular mechanism such as gene transcription. IL-4 has been reported to regulate miR-378a-3p and, indeed, we found that this microRNA was increased with IL-4 treatment. However, overexpression of miR-378a-3p in the human beta cell line EndoC-βH1 did not affect GSIS. MiR-378a-3p is transcribed from the same gene as peroxisome proliferator-activated receptor gamma co-activator 1 beta (PCG-1β) and we found that IL-4 treatment showed a clear tendency to increased gene expression of PCG-1β. PCG-1β is a co-activator of peroxisome proliferator-activated receptor gamma (PPARγ) and, the gene expression of PPARγ was also increased with IL-4 treatment. Our data suggests that the protective role of IL-4 on beta cell survival comes at the cost of lowered insulin secretion, presumably involving the PPARγ-pathway.

The Influence of Ambient Temperature on Adipose Tissue Homeostasis, Metabolic Diseases and Cancers

Adipose tissue is a recognized energy storage organ during excessive energy intake and an endocrine and thermoregulator, which interacts with other tissues to regulate systemic metabolism. Adipose tissue dysfunction is observed in most obese mouse models and humans. However, most studies using mouse models were conducted at room temperature (RT), where mice were chronically exposed to mild cold. In this condition, energy use is prioritized for thermogenesis to maintain body temperature in mice. It also leads to the activation of the sympathetic nervous system, followed by the activation of β-adrenergic signaling. As humans live primarily in their thermoneutral (TN) zone, RT housing for mice limits the interpretation of disease studies from mouse models to humans. Therefore, housing mice in their TN zone (~28–30 °C) can be considered to mimic humans physiologically. However, factors such as temperature ranges and TN pre-acclimatization periods should be examined to obtain reliable results. In this review, we discuss how adipose tissue responds to housing temperature and the outcomes of the TN zone in metabolic disease studies. This review highlights the critical role of TN housing in mouse models for studying adipose tissue function and human metabolic diseases.

Deep Proteome Profiling of White Adipose Tissue Reveals Marked Conservation and Distinct Features Between Different Anatomical Depots

White adipose tissue is deposited mainly as subcutaneous adipose tissue (SAT), often associated with metabolic protection, and abdominal/visceral adipose tissue, which contributes to metabolic disease. To investigate the molecular underpinnings of these differences, we conducted comprehensive proteomics profiling of whole tissue and isolated adipocytes from these two depots across two diets from C57Bl/6J mice. The adipocyte proteomes from lean mice were highly conserved between depots, with the major depot-specific differences encoded by just 3% of the proteome. Adipocytes from SAT (SAdi) were enriched in pathways related to mitochondrial complex I and beiging, whereas visceral adipocytes (VAdi) were enriched in structural proteins and positive regulators of mTOR presumably to promote nutrient storage and cellular expansion. This indicates that SAdi are geared toward higher catabolic activity, while VAdi are more suited for lipid storage. By comparing adipocytes from mice fed chow or Western diet (WD), we define a core adaptive proteomics signature consisting of increased extracellular matrix proteins and decreased fatty acid metabolism and mitochondrial Coenzyme Q biosynthesis. Relative to SAdi, VAdi displayed greater changes with WD including a pronounced decrease in mitochondrial proteins concomitant with upregulation of apoptotic signaling and decreased mitophagy, indicating pervasive mitochondrial stress. Furthermore, WD caused a reduction in lipid handling and glucose uptake pathways particularly in VAdi, consistent with adipocyte de-differentiation. By overlaying the proteomics changes with diet in whole adipose tissue and isolated adipocytes, we uncovered concordance between adipocytes and tissue only in the visceral adipose tissue, indicating a unique tissue-specific adaptation to sustained WD in SAT. Finally, an in-depth comparison of isolated adipocytes and 3T3-L1 proteomes revealed a high degree of overlap, supporting the utility of the 3T3-L1 adipocyte model. These deep proteomes provide an invaluable resource highlighting differences between white adipose depots that may fine-tune their unique functions and adaptation to an obesogenic environment.

Genome-wide screening for genetic variants in polyadenylation signal (PAS) sites in mouse selection lines for fatness and leanness

Alternative polyadenylation (APA) determines mRNA stability, localisation, translation and protein function. Several diseases, including obesity, have been linked to APA. Studies have shown that single nucleotide polymorphisms in polyadenylation signals (PAS-SNPs) can influence APA and affect phenotype and disease susceptibility. However, these studies focussed on associations between single PAS-SNP alleles with very large effects and phenotype. Therefore, we performed a genome-wide screening for PAS-SNPs in the polygenic mouse selection lines for fatness and leanness by whole-genome sequencing. The genetic variants identified in the two lines were overlapped with locations of PAS sites obtained from the PolyASite 2.0 database. Expression data for selected genes were extracted from the microarray expression experiment performed on multiple tissue samples. In total, 682 PAS-SNPs were identified within 583 genes involved in various biological processes, including transport, protein modifications and degradation, cell adhesion and immune response. Moreover, 63 of the 583 orthologous genes in human have been previously associated with human diseases, such as nervous system and physical disorders, and immune, endocrine, and metabolic diseases. In both lines, PAS-SNPs have also been identified in genes broadly involved in APA, such as Polr2c, Eif3e and Ints11. Five PAS-SNPs within 5 genes (Car, Col4a1, Itga7, Lat, Nmnat1) were prioritised as potential functional variants and could contribute to the phenotypic disparity between the two selection lines. The developed PAS-SNPs catalogue presents a key resource for planning functional studies to uncover the role of PAS-SNPs in APA, disease susceptibility and fat deposition.

miR-210-3p Promotes Obesity-Induced Adipose Tissue Inflammation and Insulin Resistance by Targeting SOCS1-Mediated NF-κB Pathway

Under the condition of chronic obesity, an increased level of free fatty acids along with low oxygen tension in the adipose tissue creates a pathophysiological adipose tissue microenvironment (ATenv), leading to the impairment of adipocyte function and insulin resistance. Here, we found the synergistic effect of hypoxia and lipid (H + L) surge in fostering adipose tissue macrophage (ATM) inflammation and polarization. ATenv significantly increased miR-210-3p expression in ATMs which promotes NF-κB activation-dependent proinflammatory cytokine expression along with the downregulation of anti-inflammatory cytokine expression. Interestingly, delivery of miR-210-3p mimic significantly increased macrophage inflammation in the absence of H + L co-stimulation, while miR-210-3p inhibitor notably compromised H + L-induced macrophage inflammation through increased production of suppressor of cytokine signaling 1 (SOCS1), a negative regulator of the NF-κB inflammatory signaling pathway. Mechanistically, miR-210 directly binds to the 3'-UTR of SOCS1 mRNA and silences its expression, thus preventing proteasomal degradation of NF-κB p65. Direct delivery of anti-miR-210-3p LNA in the ATenv markedly rescued mice from obesity-induced adipose tissue inflammation and insulin resistance. Thus, miR-210-3p inhibition in ATMs could serve as a novel therapeutic strategy for managing obesity-induced type 2 diabetes.

Metformin-chlorogenic acid combination reduces skeletal muscle inflammation in c57BL/6 mice on high-fat diets

BACKGROUND

Inflammation at the low-grade level has been found to contribute to obesity-induced insulin resistance in the skeletal muscle (SM). This study investigated the anti-inflammatory potential of metformin (MET) combined with chlorogenic acid (CGA) in SM of mice fed a high-fat diet (HFD).

MATERIALS AND METHODS

The C57BL/6 mice were divided into five groups of ten each, normal diet, HFD, HFD + MET, HFD + CGA and HFD + MET + CGA.

RESULTS

The results revealed that MET and CGA, alone or in combination, have a reducing effect on weight gain, plasma triglyceride, glucose and insulin levels. MET in combination with CGA led to attenuation of SM inflammation, an effect that was associated with decreasing macrophages infiltration rate. Combined treatment of MET and CGA also resulted in switching macrophages from M1 to M2 phenotype, presented by the higher expression levels of arginase and CD206 (M2 markers) and lower expression levels of iNOS and cd11c markers (M1). In addition, combination treatment was more effective in increasing the anti-inflammatory cytokines expression (IL-10) and decreasing the expression of pro-inflammatory mediators (TNF-α, IL-1β, MCP-1 and IL-6).

CONCLUSION

These findings suggest that the combination treatment of MET and CGA is likely to be a promising approach to control SM inflammation in the HFD-fed model.

Obesity and dysregulated innate immune responses: impact of micronutrient deficiencies

Obesity is associated with the development of various complications, including diabetes, atherosclerosis, and an increased risk for infections, driven by dysfunctional innate immune responses. Recent insights have revealed that the availability of nutrients is a key determinant of innate immune cell function. Although the presence of obesity is associated with overnutrition of macronutrients, several micronutrient deficiencies, including Vitamin D and zinc, are often present. Micronutrients have been attributed important immunomodulatory roles. In this review, we summarize current knowledge of the immunomodulatory effects of Vitamin D and zinc. We also suggest future lines of research to further improve our understanding of these micronutrients; this may serve as a stepping-stone to explore micronutrient supplementation to improve innate immune cell function during obesity.

Metabolically Healthy Obesity: Are Interventions Useful?

PURPOSE OF REVIEW

This review aims to detail the current global research state of metabolically healthy obesogenesis with regard to metabolic factors, disease prevalence, comparisons to unhealthy obesity, and targeted interventions to reverse or delay progression from metabolically healthy to unhealthy obesity.

RECENT FINDINGS

As a long-term condition with increased risk of cardiovascular, metabolic, and all-cause mortality risks, obesity threatens public health on a national level. The recent discovery of metabolically healthy obesity (MHO), a transitional condition during which obese persons carry comparatively lower health risks, has added to confusion about the true effect of visceral fat and subsequent long-term health risks. In this context, the evaluation of fat loss interventions, such as bariatric surgery, lifestyle changes (diet/exercise), and hormonal therapies require re-evaluation in light of evidence that progression to high-risk stages of obesity relies on metabolic status and that strategies to protect the metabolism may be useful in the prevention of metabolically unhealthy obesity. Typical calorie-based exercise and diet interventions have failed to reduce the prevalence of unhealthy obesity. Holistic lifestyle, psychological, hormonal, and pharmacological interventions for MHO, on the other hand, may at least prevent progression to metabolically unhealthy obesity.

Limonin mitigates cardiometabolic complications in rats with metabolic syndrome through regulation of the IRS-1/GLUT4 signalling pathway

Limonin is a natural triterpenoid isolated from citrus fruit. In the present study, we examined the effects of limonin on cardiometabolic alterations in diet-induced metabolic syndrome. Metabolic syndrome was induced in rats by feeding them a high-fat (HF) diet plus 15% fructose in drinking water for 16 weeks. They were treated with limonin (50 or 100 mg/kg) (n = 8/group) for the final 4 weeks. Increases in body weight (BW), fasting blood glucose (FBG), serum insulin, total cholesterol (TC), blood pressure (BP), liver fat accumulation, and adipocyte hypertrophy, as well as oral glucose tolerance in rats with metabolic syndrome were alleviated by limonin treatment (p < 0.05). Limonin improved ejection fraction and left ventricular (LV) hypertrophy, and reduced angiotensin converting enzyme (ACE) activity and angiotensin II (Ang II) concentration in rats with metabolic syndrome (p < 0.05). It also reduced plasma tumour necrosis factor (TNF)-α, interleukin (IL)- 6, leptin, malonaldehyde (MDA), and superoxide generation, and increased catalase activity in rats with metabolic syndrome compared to controls (p < 0.05). Downregulation of insulin receptor substrate 1 (IRS-1) and glucose transporter type 4 (GLUT4) protein expression in epididymal fat pads and cardiac, liver, and gastrocnemius tissues was present in metabolic syndrome, and these were restored by limonin treatment (p < 0.05). In conclusion, limonin shows a potential effect in alleviating symptoms and improving cardiometabolic disorders. These beneficial effects are linked to the reduction of the renin-angiotensin system, inflammation, oxidative stress, and improvement of IRS-1/GLUT4 protein expression in the target tissue.

The syndromic triad of COVID-19, type 2 diabetes, and malnutrition

The coronavirus disease 2019 (COVID-19) pandemic challenges our collective understanding of transmission, prevention, complications, and clinical management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Risk factors for severe infection, morbidity, and mortality are associated with age, environment, socioeconomic status, comorbidities, and interventional timing. Clinical investigations report an intriguing association of COVID-19 with diabetes mellitus and malnutrition but incompletely describe the triphasic relationship, its mechanistic pathways, and potential therapeutic approaches to address each malady and their underlying metabolic disorders. This narrative review highlights common chronic disease states that interact epidemiologically and mechanistically with the COVID-19 to create a syndromic phenotype-the COVID-Related Cardiometabolic Syndrome-linking cardiometabolic-based chronic disease drivers with pre-, acute, and chronic/post-COVID-19 disease stages. Since the association of nutritional disorders with COVID-19 and cardiometabolic risk factors is well established, a syndromic triad of COVID-19, type 2 diabetes, and malnutrition is hypothesized that can direct, inform, and optimize care. In this review, each of the three edges of this network is uniquely summarized, nutritional therapies discussed, and a structure for early preventive care proposed. Concerted efforts to identify malnutrition in patients with COVID-19 and elevated metabolic risks are needed and can be followed by improved dietary management while simultaneously addressing dysglycemia-based chronic disease and malnutrition-based chronic disease.

3-OH Phloretin Inhibits High-Fat Diet-Induced Obesity and Obesity-Induced Inflammation by Reducing Macrophage Infiltration into White Adipose Tissue

Phloretin and its glycoside phlorizin have been reported to prevent obesity induced by high-fat diet (HFD), but the effect of 3-OH phloretin, a catechol metabolite of phloretin, has not been investigated. In this study, we investigated the anti-obesity effects of phloretin and 3-OH phloretin in HFD-fed mice. The body weight gain induced by HFD was more inhibited by administration of 3-OH phloretin than by phloretin. The increases in fat mass, white adipose tissue (WAT) weight, adipocyte size, and lipid accumulation by HFD were also remarkably inhibited by 3-OH phloretin and, to a lesser extent, by phloretin. The HFD-induced upregulation of chemokines and pro-inflammatory cytokines was suppressed by 3-OH phloretin, preventing M1 macrophages from infiltrating into WAT and thereby reducing WAT inflammation. 3-OH phloretin also showed a more potent effect than phloretin on suppressing the expression of adipogenesis regulator genes, such as PPARγ2, C/EBPα, FAS, and CD36. Fasting blood glucose and insulin levels increased by HFD were diminished by the administration of 3-OH phloretin, suggesting that 3-OH phloretin may alleviate obesity-induced insulin resistance. These findings suggested that 3-OH phloretin has the potential to be a natural bioactive compound that can be used in the prevention or treatment of obesity and insulin resistance.

The interactions between inflammation and insulin resistance: molecular mechanisms in insulin-producing and insulin-dependent tissues

In the modern world the prevalence of obesity and type 2 diabetes mellitus (T2DM) significantly increases. In this light the risks of obesity-associated complications also grow up. The crucial linkage between obesity and its metabolic and cardiovascular complications is inflammatory process. The mechanism of this linkage is similar in pancreas and insulin-dependent tissues both on cells, cell-to-cell communication and signaling pathway levels: the catalysts are different lipids (cholesterol, free fatty acids, triglycerides), which are able to activate Toll-like receptors of innate immunity and inflammation. Nextly, IKK- and JNK-dependent cascades activate the secretion of inflammatory cytokines TNFa, IL-1b, IL-6 and others, which act by paracrine and autocrine manner and support inflammation both in local and systemic levels. Thus, insulin-producing and insulin-dependent tissues, which are involved in T2DM pathogenesis, through the inflammatory process integrate in pathogenic and self-maintaining cycle, which leads to the suppression of insulin secretion, pancreatic β-cell failure and the development of insulin-dependent tissues insulin resistance.

7,8-Dihydroxyflavone Attenuates Inflammatory Response and Insulin Resistance Induced by the Paracrine Interaction between Adipocytes and Macrophages

Obesity-induced inflammation and insulin resistance are mediated by macrophage infiltration into adipose tissue. We investigated the effects of 7,8-dihydroxyflavone (7,8-DHF), a flavone found in plants, on the inflammatory response and insulin resistance induced by the interaction between adipocytes and macrophages. Hypertrophied 3T3-L1 adipocytes were cocultured with RAW 264.7 macrophages and treated with 7,8-DHF (3.12, 12.5, and 50 μM). The inflammatory cytokines and free fatty acid (FFA) release were evaluated by assay kits, and signaling pathways were determined by immunoblotting. Coculture of adipocytes and macrophages increased inflammatory mediators, such as nitric oxide (NO), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) and FFA secretion but suppressed the production of anti-inflammatory adiponectin. 7,8-DHF counteracted the coculture-induced changes (p < 0.001). 7,8-DHF also inhibited c-Jun N-terminal kinase (JNK) activation and blocked nuclear factor kappa B (NF-κB) nuclear translocation in the coculture system (p < 0.01). In addition, adipocytes cocultured with macrophages did not increase glucose uptake and Akt phosphorylation in response to insulin. However, 7,8-DHF treatment recovered the impaired responsiveness to insulin (p < 0.01). These findings show that 7,8-DHF alleviates inflammation and adipocyte dysfunction in the coculture of hypertrophied 3T3-L1 adipocytes and RAW 264.7 macrophages, indicating its potential as a therapeutic agent for obesity-induced insulin resistance.

The comparison of inflammatory hematological parameters in obese and non-obese children

Introduction: Obesity is an increasing health problem in the whole world, and it has an important inflammatory component related to the insulin resistance (IR), hypertension, atherosclerosis and some cancers. This study aims to evaluate the inflammatory hematological parameters in childhood obesity.Methods: Sixty-four obese and 50 normal weight cases were included in the study. The physical examination features and laboratory data of the patients were evaluated retrospectively from the patient’s files. Laboratory tests, hematological parameters, gender were compared between the groups. Correlations between Homeostasis model evaluation for insulin resistance (HOMA-IR) and other laboratory parameters in the obese group were examined.Results: The leukocyte, neutrophile, monocyte, lymphocyte, thrombocyte and MPV values of the obese group were found to be statistically higher than the control group (p: 0.006, p:0.015, p:0.014, p:0.001, p&lt;0.001). There was no statistically significant difference between the two groups for Neutrophile/Lymphocyte ratio (NLR), Monocyte/Lymphocyte ratio (MLR) and Platelet/Lymphocyte ratio (PLR) (p:0.642, p:0.989, 0.982). Also, there was no statistically significant correlation between Homa IR and age, BMI, Neutrophil, Lymphocyte, Monocyte, Thrombocyte, Neutrophil/Lymphocyte, Monocyte/Lymphocyte and Thrombocyte/Lymphocyte values.Conclusion: The current study showed that there was no significant difference between obese and controls in terms of NLR, PLR, and MLR values. However, the leukocyte, neutrophile, monocyte, lymphocyte, thrombocyte and MPV values were statistically higher in obese group than controls. Nevertheless, these findings can point relation between obesity and inflammation.Keywords: obesity, children, inflammation, hematological parameters

The Impact of Diet and Physical Activity on Psoriasis: A Narrative Review of the Current Evidence

Psoriasis is an inflammatory disease with strong genetic links and numerous features of autoimmunity that are also influenced by environment and lifestyle, including nutritional factors and physical activity (PA), with regards to the condition of patients. Recent reports in the field of nutrigenomics indicate a significant impact of nutrients in modulating microRNAs. However, few studies have evaluated the effect of nutritional systems and PA on treating psoriasis. This narrative review updates information regarding the current dietary recommendations for individuals with psoriasis and discusses the role of diet and PA in psoriasis prevention and treatment. Application of nutrigenetics in psoriasis therapy is also discussed. The PubMed and Google Scholar databases were searched using the MeSH terms for "nutrigenomics", "dietetics", "diet therapy", "diet", "physical activity", and "exercise" in conjunction with the MeSH terms for "psoriasis" and "dermatology". Evidence has shown that patients with psoriasis should have a personalized anti-inflammatory diet. Psoriasis patients are less physically active; most performed exercises of low-to-moderate intensity and were less likely to undertake regular exercise. Identifying nutrigenomic discoveries and the current lifestyle interventions associated with psoriasis can help physicians and physical therapists develop educational programs to manage and protect against the disease.

Vitamin A: A Key Inhibitor of Adipocyte Differentiation

Inhibiting adipocyte differentiation, the conversion of preadipocytes to mature functional adipocytes, might represent a new approach to treating obesity and related metabolic disorders. Peroxisome proliferator-activated receptor γ and CCAAT-enhancer-binding protein α are two master coregulators controlling adipogenesis both in culture and in vivo. Many recent studies have confirmed the relationship between retinoic acid (RA) and the conversion of embryonic stem cells into adipocytes; however, these studies have shown that RA potently blocks the differentiation of preadipocytes into mature adipocytes. Nevertheless, the functional role of RA in early tissue development and stem cell differentiation, including in adipose tissue, remains unclear. This study highlights transcription factors that block adipocyte differentiation and maintain preadipocyte status, focusing on those controlled by RA. However, some of these novel adipogenesis inhibitors have not been validated in vivo, and their mechanisms of action require further clarification.

Taxoids-rich extract from Taxus wallichiana alleviates high-fat diet-induced insulin resistance in C57BL/6 mice through inhibition of low-grade inflammation

The needle powder of Taxus wallichiana is in use for the management of diabetes and inflammation-related complications in the Indian and Chinese Systems of Traditional Medicine but the lack of proper pharmacological intervention has prompted us to investigate the pharmacological mechanism against inflammation-induced insulin resistance in high-fat diet-fed C57BL/6 mice. Hexane (Tw-H), chloroform (Tw-C), and ethyl acetate (Tw-EA) extracts were prepared from a needle of T. wallichiana and its effect on glucose uptake against TNF-α-induced insulin resistance in skeletal muscle cells was studied. Among all, Tw-EA extract has shown promising glucose uptake potential. Tw-EA treatment is also able to decrease the lipid accumulation in adipocytes. Chemical signature of Tw-EA using HPLC showed the presence of taxoids. Efficacy of taxoids-rich extract from T. wallichiana (Tw-EA) was further validated in in vivo system against high-fat diet (HFD)-induced insulin resistance in C57BL/6 mice. Oral treatment of Tw-EA showed significant reduction in blood glucose, pro-inflammatory cytokine production and body weight gain when compared with vehicle-treated HFD-induced insulin resistance in C57BL/6 mice. Histopathology and immunohistochemistry study in skeletal muscle and adipose tissue revealed that oral treatment of Tw-EA is able to reduce the infiltration of inflammatory cells in skeletal muscles, ameliorate the hypertrophy in adipose tissue and upregulate the GLUT4 protein expression. Treatment with Tw-EA significantly up-regulated mRNA expression of insulin signaling pathway (IRS-1, PI3K, AKT, GLUT 4). This study suggested the beneficial effect of taxoids-rich extract from Taxus wallichiana against the inflammation-associated insulin resistance condition.

Kv1.3 Channel Blockade Improves Inflammatory Profile, Reduces Cardiac Electrical Remodeling, and Prevents Arrhythmia in Type 2 Diabetic Rats

PURPOSE

Kv1.3 channel regulates the activity of lymphocytes, macrophages, or adipose tissue and its blockade reduces inflammatory cytokine secretion and improves insulin sensitivity in animals with metabolic syndrome and in genetically obese mice. Thus, Kv1.3 blockade could be a strategy for the treatment of type 2 diabetes. Elevated circulating levels of TNFα and IL-1b mediate the higher susceptibility to cardiac arrhythmia in type 2 diabetic rats. We hypothesized that Kv1.3 channel blockade with the psoralen PAP1 could have immunomodulatory properties that prevent QTc prolongation and reduce the risk of arrhythmia in type 2 diabetic rats.

METHODS

Type 2 diabetes was induced to Sprague-Dawley rats by high-fat diet and streptozotocin injection. Diabetic animals were untreated, treated with metformin, or treated with PAP1 for 4 weeks. Plasma glucose, insulin, cholesterol, triglycerides, and cytokine levels were measured using commercial kits. ECG were recorded weekly, and an arrhythmia-inducing protocol was performed at the end of the experimental period. Action potentials were recorded in isolated ventricular cardiomyocytes.

RESULTS

In diabetic animals, PAP1 normalized glycaemia, insulin resistance, adiposity, and lipid profile. In addition, PAP1 prevented the diabetes-induced repolarization defects through reducing the secretion of the inflammatory cytokines IL-10, IL-12p70, GM-CSF, IFNγ, and TNFα. Moreover, compared to diabetic untreated and metformin-treated animals, those treated with PAP1 had the lowest risk of developing the life-threatening arrhythmia Torsade de Pointes under cardiac challenge.

CONCLUSION

Kv1.3 inhibition improves diabetes and diabetes-associated low-grade inflammation and cardiac electrical remodeling, resulting in more protection against cardiac arrhythmia compared to metformin.

Genetic ablation of diabetes-associated gene Ccdc92 reduces obesity and insulin resistance in mice

Multiple genome-wide association studies (GWAS) have identified specific genetic variants in the coiled-coil domain containing 92 (CCDC92) locus that is associated with obesity and type 2 diabetes in humans. However, the biological function of CCDC92 in obesity and insulin resistance remains to be explored. Utilizing wild-type (WT) and Ccdc92 whole-body knockout (KO) mice, we found that Ccdc92 KO reduced obesity and increased insulin sensitivity under high-fat diet (HFD) conditions. Ccdc92 KO inhibited macrophage infiltration and fibrosis in white adipose tissue (WAT), suggesting Ccdc92 ablation protects against adipose tissue dysfunction. Ccdc92 deletion also increased energy expenditure and further attenuated hepatic steatosis in mice on an HFD. Ccdc92 KO significantly inhibited the inflammatory response and suppressed the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in WAT. Altogether, we demonstrated the critical role of CCDC92 in metabolism, constituting a potential target for treating obesity and insulin resistance.

"Multiomics" Analyses Combined with Systems Pharmacology Reveal the Renoprotection of Mangiferin Monosodium Salt in Rats with Diabetic Nephropathy: Focus on Improvements in Renal Ferroptosis, Renal Inflammation, and Podocyte Insulin Resistance

We explored the protection of mangiferin monosodium salt (MGM) on kidney injury in rats with streptozotocin (STZ)-induced diabetic nephropathy (DN) by "multiomics" analysis combined with systems pharmacology, with a specific focus on ferroptosis, inflammation, and podocyte insulin resistance (IR) signaling events in kidneys. MGM treatment afforded renoprotective effects on rats with STZ-induced DN by alleviating systemic IR-induced renal inflammation and podocyte IR. These mechanisms were correlated mainly with the MGM treatment-induced inhibition of the mitogen-activated protein kinase/nuclear factor-kappa B axis and activation of the phosphorylated insulin receptor substrate 1(Tyr608)/phosphorylated phosphatidylinositol 3-kinase/phosphorylated protein kinase B axis in the kidneys of DN rats. MGM had an ameliorative function in renal ferroptosis in rats with STZ-induced DN by upregulating mevalonate-mediated antioxidant capacities (glutathione peroxidase 4 and ferroptosis suppressor protein 1/coenzyme Q10 axis) and weakening acyl-CoA synthetase long-chain family member 4-mediated proferroptotic generation of lipid drivers in kidneys. MGM may be a promising alternative strategy for the treatment of DN.

Advancements in lead therapeutic phytochemicals polycystic ovary syndrome: A review

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases in women of reproductive age and features complex pathological symptoms and mechanisms. Existing medical treatments have, to some extent, alleviated the deterioration of PCOS. However, these strategies only temporarily control symptoms, with a few side effects and no preventive effect. Phytochemicals extracted from medicinal herbs and plants are vital for discovering novel drugs. In recent years, many kinds of research have proven that phytochemicals isolated from traditional Chinese medicine (TCM) and medicinal plants show significant potential in preventing, alleviating, and treating PCOS. Nevertheless, compared to the abundance of experimental literature and minimal specific-topic reviews related to PCOS, there is a lack of systematic reviews to summarize these advancements in this promising field. Under this background, we systematically document the progress of bioactive phytochemicals from TCM and medicinal plants in treating PCOS, including flavonoids, polyphenols, and alkaloids. According to the literature, these valuable phytochemicals demonstrated therapeutic effects on PCOS supported by in vivo and in vitro experiments, mainly depending on anti-inflammatory, antioxidation, improvement of hormone disorder and insulin resistance (IR), and alleviation of hyperinsulinemia. Based on the current progress, future research directions should emphasize 1) exploring bioactive phytochemicals that potentially mediate bone metabolism for the treatment of PCOS; 2) improving unsatisfactory bioavailability by using advanced drug delivery systems such as nanoparticles and antibody-conjugated drugs, as well as a chemical modification; 3) conducting in-depth research on the pathogenesis of PCOS to potentially impact the gut microbiota and its metabolites in the evolution of PCOS; 4) revealing the pharmacological effects of these bioactive phytochemicals on PCOS at the genetic level; and 5) exploring the hypothetical and unprecedented functions in regulating PCOS by serving as proteolysis-targeting chimeras and molecular glues compared with traditional small molecule drugs. In brief, this review aims to provide detailed mechanisms of these bioactive phytochemicals and hopefully practical and reliable insight into clinical applications concerning PCOS.

Study on the role of calcium channel protein TRPV4 in the inflammatory pathway of type 2 diabetic adipose tissue based on gene databases

BACKGROUND

Chronic inflammation of adipose tissue may be one of the key factors contributing to the development of insulin resistance in T2DM adipose tissue. Transient receptor potential vanilloid type 4 (TRPV4) can be involved in a variety of cellular inflammatory responses. In this study, we evaluated the role of TRPV4 channelin in the T2DM adipose tissue inflammatory pathway.

METHODS

Based on the gene expression profiling data of the public database, bioinformatics methods were used to screen the target gene population of the TRPV4 channel protein involved in the regulation of T2DM fat cells. A mature adipocyte model was constructed to verify the expression level of target genes and to evaluate the regulatory effect of TRPV4 channel inhibition on target genes of inflammation-related pathways.

RESULTS

In shTRPV4 adipocytes, 144 genes with downregulation expression were screened, a PPI network was constructed and a core module containing 15 genes was screened out, and the core genes were mainly enriched in the Toll-like receptor signaling pathway through enrichment analysis. Constructing a mature adipocyte model found that the TRPV4 inhibitor HC067047 inhibited the effect of upregulation of the expression level of the relevant gene in the signaling pathway.

CONCLUSIONS

Our findings suggest that the expression of highly expressed pro-inflammatory cytokines and chemokines in T2DM adipose tissue decreases after inhibiting the expression of TRPV4 in adipocytes, suggesting that TRPV4 may become a potential drug target for the treatment of T2DM.

The Novel Inhibitory Effect of YM976 on Adipocyte Differentiation

The pyrimidine derivative YM976 (4-(3-chlorophenyl)-1,7-diethylpyrido(2,3-d)-pyrimidin-2(1H)-one) exerts anti-inflammatory and anti-asthmatic effects. Considering that accumulation of lipids in adipose tissue is accompanied by inflammation, we investigated whether YM976 affects adipocyte differentiation. We found that YM976 significantly decreased lipid accumulation without cytotoxicity and reduced the expression levels of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα) as well as their lipogenic regulators including fatty acid synthase (FASN) and fatty acid-binding protein 4 (FABP4) in 3T3-L1 cells induced for differentiation. YM976 mainly inhibited the early stage of adipocyte differentiation. Furthermore, intracellular cAMP level was elevated by YM976 resulting in increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK). Conversely, decreasing the levels of AMPK or treatment with Compound C, an AMPK inhibitor, lessened the suppressive effects of YM976 on PPARγ transcriptional activity and adipogenesis. Thus, our results suggest YM976 as a novel potential compound for controlling lipid accumulation and formation of adipocytes in obesity.

Molecular aspects of COVID-19 and its relationship with obesity and physical activity: a narrative review

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 has several mechanisms of action related to inflammatory responses, especially in individuals diagnosed with obesity. This hyperinflammatory clinical profile resulting from the association between obesity and coronavirus disease 2019 (COVID-19) may be attenuated by regular physical activity.

OBJECTIVE

The aim of this study was to review the evidence on the consequences of physical inactivity and physical activity on COVID-19 in patients with obesity.

DESIGN AND SETTING

Narrative review at the Bahiana School of Medicine and Public Health in Salvador, Brazil.

METHODS

We searched evidence on the association of COVID-19 with physical activity and obesity using the following keywords: "covid-19," "physical activity," and "obesity". The databases used were MEDLINE (PubMed), ScienceDirect, and Virtual Health Library. Studies published from 2019 to 2021 and available in Portuguese, English, and Spanish were included. The final search was conducted on September 26, 2021.

RESULTS

We identified 661 studies in the database, among which 71 were considered for inclusion in the narrative review of the molecular aspects of COVID-19 and its relationship with physical activity and obesity.

CONCLUSION

This literature review enabled the perception of the relationship between the molecular mechanisms of COVID-19 and obesity. Regular physical activity had various benefits for the inflammatory condition of the studied population, highlighting moderate-intensity.

Hyperinsulinemia: an early biomarker of metabolic dysfunction

Introduction

Hyperinsulinemia in the absence of impaired glucose tolerance and normal HbA1c is considered indicative of pre-diabetes. Very few Indian studies have focused on hyperinsulinemia particularly in young adults. The present study aimed to determine whether hyperinsulinemia may be present despite HbA1c being normal.

Methods

This was a cross-sectional study conducted on adolescents and young adults aged 16-25 years living in Mumbai, India. The participants attended various academic institutions and were those who underwent screening as the first step of a clinical trial for studying the efficacy of almond intake in prediabetes.

Results

Among this young population (n=1313), 4.2% (n=55) of the participants were found to be prediabetic (ADA criteria) and 19.7% of them had HbA1c levels between 5.7%-6.4%. However, almost, 30.5% had hyperinsulinemia inspite of normal blood glucose levels and normal HbA1c. Among those with HbA1c<5.7 (n=533), 10.5% (n=56) participants had fasting insulin>15 mIU/L and a higher percentage (39.4%, n=260) had stimulated insulin above 80 mIU/L. These participants had higher mean anthropometric markers than those with normal fasting and/or stimulated insulin.

Conclusion

Hyperinsulinaemia in the absence of impaired glucose tolerance and normal HbA1c may provide a much earlier indicator of detection for risk of metabolic disease and progression to metabolic syndrome and diabetes mellitus.

Comparing the effects of docosahexaenoic and eicosapentaenoic acids on cardiovascular risk factors: Pairwise and network meta-analyses of randomized controlled trials

BACKGROUND

Evidence from clinical trial studies suggests that docosahexaenoic acids (DHA) may have greater potential effects on improving cardiovascular risk factors than eicosapentaenoic acid (EPA). However, this evidence has not yet been meta-analyzed and quantified. The aim of this study was to evaluate and compare the effect of DHA and EPA monotherapy on cardiovascular risk factors based on paired and network meta-analysis.

METHODS

Relevant articles published up to January 2022 were systematically retrieved from relevant databases. We included all Randomized Controlled Trials (RCTs) on adults that directly compared the effects of DHA with EPA and RCTs of indirect comparisons (DHA and EPA monotherapy compared to control groups). Data were pooled by pairwise and network meta-analysis and expressed as mean differences (MDs) with 95% CIs. The study protocol was registered with PROSPERO (Registration ID: CRD42022328630).

RESULTS

Network meta-analysis of comparisons of DHA and EPA suggested significant comparable effects only on LDL-C (MD EPA versus DHA = -8.51 mg/L; 95% CI: -16.67; -0.35). However, the Network meta-analysis not show a significant effect for other risk factors. Furthermore, pairwise meta-analysis of direct comparisons of DHA and EPA showed significant difference in their effects on plasma glucose (MD _{EPA versus DHA} = -0.31 mg/L; 95% CI: -0.60, -0.02), Insulin (MD _{EPA versus DHA} = -2.14 mg/L; 95% CI: -3.26, -1.02), but the results were not significant for risk factors.

CONCLUSION

Our findings suggest that both EPA and DHA act similarly on the markers under study, with slight changes in plasma glucose, insulin, and LDL-C.

Associations of circulating levels of phthalate metabolites with cytokines and acute phase reactants in a Spanish human cohort

The associations between human phthalate exposure and the onset of chronic diseases with an immunological component (e.g., metabolic syndrome, cancer) remain unclear, partly due to the uncertainties in the underlying mechanisms. This study investigates cross-sectional associations of the concentrations of 10 phthalate metabolites with 19 cytokines and acute phase proteins in 213 serum samples of Spanish adults. The associations were explored by Spearman's correlation, multivariable linear regression, and weighted quantile sum regression analyses. In the multivariable analyses, levels of plasminogen activator inhibitor (PAI)-1 were positively associated with mono-n-butyl phthalate (fold-change per one IQR increase in phthalate levels, 95% Confidence Interval: 1.65, 1.45-1.88) and mono-iso-butyl phthalate (3.07, 2.39-3.95), mono-ethyl phthalate (2.05, 1.62-2.61), as well as categorized mono-iso-decyl and mono-benzyl phthalates. The same phthalates also were significantly associated with leptin, interleukin (IL)-18 and monocyte chemoattractant protein-1. Moreover, the proinflammatory markers IL-1β, IL-17, IL-8, IL-6, IL-12, tumor necrosis factor, and lipopolysaccharide-binding protein showed positive and negative associations with, respectively, mono-(2-ethyl-hexyl) and mono-methyl phthalates. Finally, phthalate mixtures were positively associated with PAI-1, leptin, IL-18, IL-12, IL-8 and IL-1β. Despite the cross-sectional design limitation, these associations point to relevant subclinical immuno-inflammatory actions of these pollutants, warranting confirmation in future studies.

Relationship between Components, Intestinal Microbiota, and Mechanism of Hypoglycemic Effect of the Saggy Ink Cap Medicinal Mushroom (Coprinus Comatus, Agaricomycetes): A Review

Coprinus comatus is rich in a variety of nutrients, which has been reported to display a good hypoglycemic effect. However, there is no consensus on the hypoglycemic mechanism of this mushroom. Intestinal microbiota, a complex and intrinsic system, is closely related to metabolism. In this review, we discussed the potential relationship between certain components of C. comatus and intestinal microbiota to illustrate the possible hypoglycemic mechanism of C. comatus through intestinal microbiota. It will provide a new perspective for the study of hypoglycemic mechanism of C. comatus and promote the development and utilization of this mushroom.

Coptis chinensis, and extracts of guava and mulberry leaves present good inhibiting potential on obesity and associated metabolic disorders in high-fat diet obesity mice model

This study aimed to investigate the anti-obesity effects of Coptis chinensis (CC), BALASAN (combinational guava leaf extract and mulberry leaf extract), and CC/BALASAN (CC/BAL) on high-fat diet-induced obese C57BL/6 mice and to explore possible mediating mechanisms in 3T3-L1 pre-adipocytes. Oil red-O stain was used to test the effects of CC, BALASAN, and CC/BAL on the differentiation of 3T3-L1 pre-adipocytes. Additionally, real-time PCR was used to detect the expression of genes involved in adipocyte differentiation and inflammation-related genes in adipose tissue of mice that were fed a high-fat diet. CC, BALASAN, and CC/BAL inhibited the differentiation of 3T3-L1 pre-adipocytes and exhibited excellent inhibitory ability against the expression of PPARγ and RXRα genes associated with adipocyte differentiation. Replenishing mice with a high-fat diet with CC, BALASAN, and CC/BAL reduced body weight gaining and blood glucose and plasma cholesterol levels. CC also effectively reduced liver weight, whereas BALASAN and CC/BAL had no inhibitory effect. In addition, CC effectively inhibited the expression of C/EBP-α in adipose tissue. Interestingly, BALASAN not only inhibited the expression of C/EBP-α, but also that of PPARγ, RXRα, and TNFα. Such data indicated that CC, BALASAN, and CC/BAL may have potentially beneficial effects against obesity and associated metabolic disorders by down-regulating the PPARγ/RXRα pathway.

Phenotypic diversity of human adipose tissue-resident NK cells in obesity

Natural killer (NK) cells have emerged as key mediators of obesity-related adipose tissue inflammation. However, the phenotype of NK cell subsets residing in human adipose tissue are poorly defined, preventing a detailed understanding of their role in metabolic disorders. In this study, we applied multicolor flow cytometry to characterize CD56^bright and CD56^dim NK cells in blood and adipose tissue depots in individuals with obesity and identified surface proteins enriched on adipose tissue-resident CD56^bright NK cells. Particularly, we found that adipose tissue harbored clusters of tissue-resident CD56^bright NK cells signatured by the expression of CD26, CCR5 and CD63, possibly reflecting an adaptation to the microenvironment. Together, our findings provide broad insights into the identity of NK cells in blood and adipose tissue in relation to obesity.

Supplemental wheat germ modulates phosphorylation of STAT3 in the gut and NF-κBp65 in the adipose tissue of mice fed a Western diet

Background

Commensal gut bacteria, including Lactobacillus, can produce metabolites that stimulate the release of gut antimicrobial peptides (AMPs) via the signal transducer and activator of transcription (STAT)3 pathway and prevent obesity-associated leaky gut and chronic inflammation. We have previously reported that wheat germ (WG) selectively increased cecal Lactobacillus in obese mice.

Objectives

This study investigated the effects of WG on gut STAT3 activation and AMPs (Reg3γ and Reg3β) as well as the potential of WG to inhibit nuclear Nf-κB-activation and immune cell infiltration in the visceral adipose tissue (VAT) of mice fed a Western diet (i.e., high-fat and sucrose diet [HFS]).

Methods

Six-wk-old male C57BL/6 mice were randomly assigned to 4 groups (n = 12/group): control (C, 10% fat and sucrose kcal) or HFS (45% fat and 26% sucrose kcal) diet with or without 10% WG (wt/wt) for 12 wk. Assessments include serum metabolic parameters jejunal AMPs genes, inflammatory markers, and phosphorylation of STAT3 as well as VAT NF-κBp65. Independent and interaction effects of HFS and WG were analyzed with a 2-factor ANOVA.

Results

WG significantly improved markers of insulin resistance and upregulated jejunal Il10 and Il22 genes. The HFS + WG group had a 15-fold increase in jejunal pSTAT3 compared with the HFS group. Consequently, WG significantly upregulated jejunal mRNA expression of Reg3γ and Reg3β. The HFS group had a significantly higher VAT NF-κBp65 phosphorylation than the C group, while the HFS + WG group suppressed this to the level of C. Moreover, VAT Il6 and Lbp genes were downregulated in the HFS + WG group compared with HFS. Genes related to macrophage infiltration in the VAT were repressed in the WG-fed mice.

Conclusion

These findings show the potential of WG to influence vital regulatory pathways in the gut and adipose tissue which may reduce the chronic inflammatory burden on these tissues that are important targets in obesity and insulin resistance.

Neuronal growth regulator 1 may modulate interleukin-6 signaling in adipocytes

Interleukin-6 (IL-6) is a pleiotropic cytokine that plays both anti- and pro-inflammatory roles. Due to the restricted expression of membrane IL-6 receptor (IL-6R), most pro-inflammatory functions of IL-6 are attributed to its association with soluble IL-6R (sIL-6R). Neuronal growth regulator 1 (NEGR1) is a brain-enriched membrane protein that has recently been recognized as a risk factor for many human diseases including obesity, depression, and autism. In the present study, we report that the expression levels of IL-6 and IL-6R, as well as the phosphorylation of signal transducer and activator of transcription (STAT) 3, were significantly elevated in white adipose tissues of Negr1 knockout mice. Elevated levels of circulating IL-6 and sIL-6R have also been observed in Negr1 ^-/- mice. Furthermore, NEGR1 interacted with IL-6R, which was supported by subcellular fractionation and an in situ proximity ligation assay. Importantly, NEGR1 expression attenuated the phosphorylation of STAT3 by sIL-6R, suggesting that NEGR1 negatively regulates IL-6 trans-signaling. Taken together, we propose that NEGR1 may play a regulatory role in IL-6 signaling by interacting with IL-6R, which may contribute to a molecular link underlying obesity, inflammation, and the depression cycle.

Unraveling the Mechanism of Immunity and Inflammation Related to Molecular Signatures Crosstalk Among Obesity, T2D, and AD: Insights From Bioinformatics Approaches

Individuals with type 2 diabetes (T2D) and obesity have a higher risk of developing Alzheimer disease (AD), and increasing evidence indicates a link between impaired immune signaling pathways and the development of AD. However, the shared cellular mechanisms and molecular signatures among these 3 diseases remain unknown. The purpose of this study was to uncover similar molecular markers and pathways involved in obesity, T2D, and AD using bioinformatics and a network biology approach. First, we investigated the 3 RNA sequencing (RNA-seq) gene expression data sets and determined 224 commonly shared differentially expressed genes (DEGs) from obesity, T2D, and AD diseases. Gene ontology and pathway enrichment analyses revealed that mutual DEGs were mainly enriched with immune and inflammatory signaling pathways. In addition, we constructed a protein-protein interactions network for finding hub genes, which have not previously been identified as playing a critical role in these 3 diseases. Furthermore, the transcriptional factors and protein kinases regulating commonly shared DEGs among obesity, T2D, and AD were also identified. Finally, we suggested potential drug candidates as possible therapeutic interventions for 3 diseases. The results of this bioinformatics analysis provided a new understanding of the potential links between obesity, T2D, and AD pathologies.

Adipose tissue aging is regulated by an altered immune system

Adipose tissue is a widely distributed organ that plays a critical role in age-related physiological dysfunctions as an important source of chronic sterile low-grade inflammation. Adipose tissue undergoes diverse changes during aging, including fat depot redistribution, brown and beige fat decrease, functional decline of adipose progenitor and stem cells, senescent cell accumulation, and immune cell dysregulation. Specifically, inflammaging is common in aged adipose tissue. Adipose tissue inflammaging reduces adipose plasticity and pathologically contributes to adipocyte hypertrophy, fibrosis, and ultimately, adipose tissue dysfunction. Adipose tissue inflammaging also contributes to age-related diseases, such as diabetes, cardiovascular disease and cancer. There is an increased infiltration of immune cells into adipose tissue, and these infiltrating immune cells secrete proinflammatory cytokines and chemokines. Several important molecular and signaling pathways mediate the process, including JAK/STAT, NFκB and JNK, etc. The roles of immune cells in aging adipose tissue are complex, and the underlying mechanisms remain largely unclear. In this review, we summarize the consequences and causes of inflammaging in adipose tissue. We further outline the cellular/molecular mechanisms of adipose tissue inflammaging and propose potential therapeutic targets to alleviate age-related problems.

Is insulin resistance tissue-dependent and substrate-specific? The role of white adipose tissue and skeletal muscle

Insulin resistance (IR) refers to a reduction in the ability of insulin to exert its metabolic effects in organs such as adipose tissue (AT) and skeletal muscle (SM), leading to chronic diseases such as type 2 diabetes, hepatic steatosis, and cardiovascular diseases. Obesity is the main cause of IR, however not all subjects with obesity develop clinical insulin resistance, and not all clinically insulin-resistant people have obesity. Recent evidence implies that IR onset is tissue-dependent (AT or SM) and/or substrate-specific (glucometabolic or lipometabolic). Therefore, the aims of the present review are 1) to describe the glucometabolic and lipometabolic activities of insulin in AT and SM in the maintenance of whole-body metabolic homeostasis, 2) to discuss the pathophysiology of substrate-specific IR in AT and SM, and 3) to highlight novel validated tests to assess tissue and substrate-specific IR that are easy to perform in clinical practice. In AT, glucometabolic IR reduces glucose availability for glycerol and fatty acid synthesis, thus decreasing the esterification and synthesis of signaling bioactive lipids. Lipometabolic IR in AT impairs the antilipolytic effect of insulin and lipogenesis, leading to an increase in circulating FFAs and generating lipotoxicity in peripheral tissues. In SM, glucometabolic IR reduces glucose uptake, whereas lipometabolic IR impairs mitochondrial lipid oxidation, increasing oxidative stress and inflammation, all of which lead to metabolic inflexibility. Understanding tissue-dependent and substrate-specific IR is of paramount importance for early detection before clinical manifestations and for the development of more specific treatments or direct interventions to prevent chronic life-threatening diseases.

Diet, sleep, and exercise in inflammatory skin diseases

Inflammatory skin conditions are significantly impacted by lifestyle habits, particularly those related to diet, exercise, and sleep. Although ancient cultures emphasized the importance of lifestyle behaviors as both etiology and therapy in disease, modern medicine often overlooks nonpharmacological therapy. However, recent studies show that diet can have a significant impact on inflammatory skin diseases such as psoriasis, hidradenitis suppurativa, and atopic dermatitis. Foods high in glycemic index, advanced glycation end-products, and omega-6 polyunsaturated fatty acids are associated with obesity and systemic inflammation, which can exacerbate inflammatory skin diseases. In addition, lifestyle behaviors such as exercise and sleep have been shown to have positive effects on inflammatory skin diseases. This review aims to highlight the importance of lifestyle behaviors in the context of inflammation and inflammatory dermatoses.

Apolipoprotein A-IV reduced metabolic inflammation in white adipose tissue by inhibiting IKK and JNK signaling in adipocytes

Apolipoprotein A-IV (ApoA-IV) plays a role in satiation and serum lipid transport. In diet-induced obesity (DIO) C57BL/6J mice, ApoA-IV deficiency induced in ApoA-IV-/-knock-out (KO mice) resulted in increased bodyweight, insulin resistance (IR) and plasma free fatty acid (FFA), which was partially reversed by stable ApoA-IV-green fluorescent protein (KO-A4-GFP) transfection in KO mice. DIO KO mice exhibited increased M1 macrophages in epididymal white adipose tissue (eWAT) as well as in the blood. Based on RNA-sequencing analyses, cytokine-cytokine receptor interactions, T cell and B cell receptors, and especially IL-17 and TNF-α, were up-regulated in eWAT of DIO ApoA-IV KO compared with WT mice. Supplemented ApoA-IV suppressed lipopolysaccharide (LPS)-induced IKK and JNK phosphorylation in Raw264.7 macrophage cell culture assays. When the culture medium was supplemented to 3T3-L1 adipocytes they exhibited an increased sensitivity to insulin. ApoA-IV protects against obesity-associated metabolic inflammation mainly through suppression in M1 macrophages of eWAT, IL17-IKK and IL17-JNK activity.

Essential Minerals and Metabolic Adaptation of Immune Cells

Modern lifestyles deviated considerably from the ancestral routines towards major shifts in diets and increased sedentarism. The trace elements status of the human body is no longer adequately supported by micronutrient-inferior farmed meats and crop commodities produced by the existing agricultural food systems. This is particular evident in the increased obesogenic adipogenesis and low-grade inflammation that fails to resolve with time. The metabolically restrictive environment of the inflamed tissues drives activation and proliferation of transient and resident populations of immune cells in favor of pro-inflammatory phenotypes, as well as a part of the enhanced autoimmune response. As different stages of the immune activation and resolution depend on the availability of specific minerals to maintain the structural integrity of skin and mucus membranes, activation and migration of immune cells, activation of the complement system, and the release of pro-inflammatory cytokines and chemokines, this review discusses recent advances in our understanding of the contribution of select minerals in optimizing the responses of innate and adaptive immune outcomes. An abbreviated view on the absorption, transport, and delivery of minerals to the body tissues as related to metabolic adaptation is considered.

Specific S100 Proteins Bind Tumor Necrosis Factor and Inhibit Its Activity

Tumor necrosis factor (TNF) inhibitors (anti-TNFs) represent a cornerstone of the treatment of various immune-mediated inflammatory diseases and are among the most commercially successful therapeutic agents. Knowledge of TNF binding partners is critical for identification of the factors able to affect clinical efficacy of the anti-TNFs. Here, we report that among eighteen representatives of the multifunctional S100 protein family, only S100A11, S100A12 and S100A13 interact with the soluble form of TNF (sTNF) in vitro. The lowest equilibrium dissociation constants (K_d) for the complexes with monomeric sTNF determined using surface plasmon resonance spectroscopy range from 2 nM to 28 nM. The apparent K_d values for the complexes of multimeric sTNF with S100A11/A12 estimated from fluorimetric titrations are 0.1-0.3 µM. S100A12/A13 suppress the cytotoxic activity of sTNF against Huh-7 cells, as evidenced by the MTT assay. Structural modeling indicates that the sTNF-S100 interactions may interfere with the sTNF recognition by the therapeutic anti-TNFs. Bioinformatics analysis reveals dysregulation of TNF and S100A11/A12/A13 in numerous disorders. Overall, we have shown a novel potential regulatory role of the extracellular forms of specific S100 proteins that may affect the efficacy of anti-TNF treatment in various diseases.

Orphan receptor GPR50 attenuates inflammation and insulin signaling in 3T3-L1 preadipocytes

Type 2 diabetes (T2DM) is characterized by insulin secretion deficiencies and systemic insulin resistance (IR) in adipose tissue, skeletal muscle, and the liver. Although the mechanism of T2DM is not yet fully known, inflammation and insulin resistance play a central role in the pathogenesis of T2DM. G protein-coupled receptors (GPCRs) are involved in endocrine and metabolic processes as well as many other physiological processes. GPR50 (G protein-coupled receptor 50) is an orphan GPCR that shares the highest sequence homology with melatonin receptors. The aim of this study was to investigate the effect of GPR50 on inflammation and insulin resistance in 3T3-L1 preadipocytes. GPR50 expression was observed to be significantly increased in the adipose tissue of obese T2DM mice, while GPR50 deficiency increased inflammation in 3T3-L1 cells and induced the phosphorylation of AKT and insulin receptor substrate (IRS) 1. Furthermore, GPR50 knockout in the 3T3-L1 cell line suppressed PPAR-γ expression. These data suggest that GPR50 can attenuate inflammatory levels and regulate insulin signaling in adipocytes. Furthermore, the effects are mediated through the regulation of the IRS1/AKT signaling pathway and PPAR-γ expression.

Probiotics' effect on visceral and subcutaneous adipose tissue: a systematic review of randomized controlled trials

Probiotics are shown to alter the microbiota, leading to a favorable environment, in which weight loss and metabolic parameters are improve. However, the results on probiotics' effect on specific types of central adipose tissues, mainly visceral (VAT) and subcutaneous adipose tissue (SAT), are conflicting. Therefore, we conducted a systematic review, aimed to evaluate the effects of probiotics on VAT and SAT. PubMed, SCOPUS, EBSCO, and LILACS databases were searched for studies that investigated the effect of probiotics on VAT and SAT. Fixed effects were used to calculate the pooled difference in means (DM) and 95% confidence intervals (95%CI). Fourteen publications met the inclusion criteria, which consisted of 1523 participants. For VAT, overall, there was a significant decrease (DM = -3.63 cm2, 95% CI: -5.08 to -2.17, p < 0.001). When stratified by type of probiotic, single Bifidobacterium (DM = -4.49 cm2, 95% CI:-7.37 to -1.61, p = 0.002) and single Lactobacillus probiotics (DM = -3.84 cm2, 95% CI:-5.74 to -1.93, p < 0.001) resulted in significant reductions. Mixed probiotics had no effect. For SAT, overall, there was a significant decrease (DM = -2.91 cm2, 95% CI:-4.82 to -1.01, p = 0.003), and when stratified by type of probiotic, single Lactobacillus (DM = -3.39 cm2, 95% CI:-5.90 to -0.88, p = 0.008) and mixed probiotics (DM = -5.97 cm2, 95% CI:-10.32 to -1.62, p = 0.007) resulted in a significant decrease. Single Bifidobacterium probiotics had no effect. Using meta-regression, no association was observed between the total daily probiotic dose and VAT or SAT reduction. This study shows that probiotics have a beneficial effect on central adiposity. Single Lactobacillus-based probiotics reduced VAT and SAT, whereas Bifidobacterium-based probiotics reduce VAT.

Connecting epicardial adipose tissue and heart failure with preserved ejection fraction: mechanisms, management and modern perspectives

Obesity is very common in patients with heart failure with preserved ejection fraction (HFpEF) and it has been suggested that obesity plays an important role in the pathophysiology of this disease. While body mass index defines the presence of obesity, this measure provides limited information on visceral adiposity, which is probably more relevant in the pathophysiology of HFpEF. Epicardial adipose tissue is the visceral fat situated directly adjacent to the heart and recent data demonstrate that accumulation of epicardial adipose tissue is associated with the onset, symptomatology and outcome of HFpEF. However, the mechanisms by which epicardial adipose tissue may be involved in HFpEF remain unclear. It is also questioned whether epicardial adipose tissue may be a specific target for therapy for this disease. In the present review, we describe the physiology of epicardial adipose tissue and the pathophysiological transformation of epicardial adipose tissue in response to chronic inflammatory diseases, and we postulate conceptual mechanisms on how epicardial adipose tissue may be involved in HFpEF pathophysiology. Lastly, we outline potential treatment strategies, knowledge gaps and directions for further research.

Inflammaging and body composition: New insights in diabetic and hypertensive elderly men

Age-related changes in the body's physiological responses play a critical role in systemic arterial hypertension (SAH) and type 2 Diabetes mellitus (T2DM). SAH and T2DM have clinically silent low-grade inflammation as a common risk factor. This inflammation has a relevant element, the excess of fatty tissue. In this scenario, little is known about how inflammatory markers interact with each other. Therefore, this work evaluated the interplay among anthropometric, biochemical, and inflammatory markers in the elderly with SAH and T2DM. Men aged 60-80 years old with SAH and T2DM were classified by body mass index (BMI) as eutrophic elderly (EE, 24 individuals) or overweight elderly (OE, 25 individuals). Body composition analysis was performed using bioimpedance. Blood samples were collected to perform inflammatory and biochemical evaluations. The cytokines IL-17A, IL-1β, IFN-y, TNF-α, and IL-10, were evaluated by ELISA. Triglycerides, total and fractions of cholesterol, and glucose were measured by spectrophotometry. Overweight elderly men had a higher glycemic index and an increase in most anthropometric markers, as well as higher means for all pro-inflammatory cytokines analyzed (IL-17A, IL-1β, IFN-y, and TNF-α) in comparison to their eutrophic elderly counterparts. However, there was a decrease in IL-10 anti-inflammatory cytokine and IL-10/IL-17A ratio compared to their eutrophic elderly counterparts. Although overweight elderly men have worsening inflammatory parameters, the magnitude of their correlations with anthropometric and biochemical parameters becomes less evident. The Bayesian networks highlight that in the eutrophic elderly, IL-17A and TNF-α are the cytokines most associated with interactions, and most of these interactions occur with biochemical parameters. It is worth highlighting the role of IFN-y in overweight elderly men. This cytokine influences IL-10 and TNF-α production, contributing to the inflammatory profile exacerbated in this group.

High-fat diet-induced obesity augments the deleterious effects of estrogen deficiency on bone: Evidence from ovariectomized mice

Several epidemiological studies have suggested that obesity complicated with insulin resistance and type 2 diabetes exerts deleterious effects on the skeleton. While obesity coexists with estrogen deficiency in postmenopausal women, their combined effects on the skeleton are poorly studied. Thus, we investigated the impact of high-fat diet (HFD) on bone and metabolism of ovariectomized (OVX) female mice (C57BL/6J). OVX or sham operated mice were fed either HFD (60%fat) or normal diet (10%fat) for 12 weeks. HFD-OVX group exhibited pronounced increase in body weight (~86% in HFD and ~122% in HFD-OVX, p < 0.0005) and impaired glucose tolerance. Bone microCT-scanning revealed a pronounced decrease in trabecular bone volume/total volume (BV/TV) (-15.6 ± 0.48% in HFD and -37.5 ± 0.235% in HFD-OVX, p < 0.005) and expansion of bone marrow adipose tissue (BMAT; +60.7 ± 9.9% in HFD vs. +79.5 ± 5.86% in HFD-OVX, p < 0.005). Mechanistically, HFD-OVX treatment led to upregulation of genes markers of senescence, bone resorption, adipogenesis, inflammation, downregulation of gene markers of bone formation and bone development. Similarly, HFD-OVX treatment resulted in significant changes in bone tissue levels of purine/pyrimidine and Glutamate metabolisms, known to play a regulatory role in bone metabolism. Obesity and estrogen deficiency exert combined deleterious effects on bone resulting in accelerated cellular senescence, expansion of BMAT and impaired bone formation leading to decreased bone mass. Our results suggest that obesity may increase bone fragility in postmenopausal women.

Vitamin C attenuates predisposition to high-fat diet-induced metabolic dysregulation in GLUT10-deficient mouse model

Background

The development of type 2 diabetes mellitus (T2DM) is highly influenced by complex interactions between genetic and environmental (dietary and lifestyle) factors. While vitamin C (ascorbic acid, AA) has been suggested as a complementary nutritional treatment for T2DM, evidence for the significance and beneficial effects of AA in T2DM is thus far inconclusive. We suspect that clinical studies on the topic might need to account for combination of genetic and dietary factors that could influence AA effects on metabolism. In this study, we tested this general idea using a mouse model with genetic predisposition to diet-induced metabolic dysfunction. In particular, we utilized mice carrying a human orthologous GLUT10^G128E variant (GLUT10^G128E mice), which are highly sensitive to high-fat diet (HFD)-induced metabolic dysregulation. The genetic variant has high relevance to human populations, as genetic polymorphisms in glucose transporter 10 (GLUT10) are associated with a T2DM intermediate phenotype in nondiabetic population.

Results

We investigated the impacts of AA supplementation on metabolism in wild-type (WT) mice and GLUT10^G128E mice fed with a normal diet or HFD. Overall, the beneficial effects of AA on metabolism were greater in HFD-fed GLUT10^G128E mice than in HFD-fed WT mice. At early postnatal stages, AA improved the development of compromised epididymal white adipose tissue (eWAT) in GLUT10^G128E mice. In adult animals, AA supplementation attenuated the predisposition of GLUT10^G128E mice to HFD-triggered eWAT inflammation, adipokine dysregulation, ectopic fatty acid accumulation, metabolic dysregulation, and body weight gain, as compared with WT mice.

Conclusions

Taken together, our findings suggest that AA has greater beneficial effects on metabolism in HFD-fed GLUT10^G128E mice than HFD-fed WT mice. As such, AA plays an important role in supporting eWAT development and attenuating HFD-induced metabolic dysregulation in GLUT10^G128E mice. Our results suggest that proper WAT development is essential for metabolic regulation later in life. Furthermore, when considering the usage of AA as a complementary nutrition for prevention and treatment of T2DM, individual differences in genetics and dietary patterns should be taken into account.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12263-022-00713-y.

Second malignant neoplasms in lymphomas, secondary lymphomas and lymphomas in metabolic disorders/diseases

With inconsistent findings, evidence has been obtained in recent years that metabolic disorders are closely associated with the development of lymphomas. Studies and multiple analyses have been published also indicating that some solid tumor survivors develop a secondary lymphoma, whereas some lymphoma survivors subsequently develop a second malignant neoplasm (SMN), particularly solid tumors. An interaction between the multiple etiologic factors such as genetic factors and late effects of cancer therapy may play an important role contributing to the carcinogenesis in patients with metabolic diseases or with a primary cancer. In this review, we summarize the current knowledge of the multiple etiologic factors for lymphomagenesis, focusing on the SMN in lymphoma, secondary lymphomas in primary cancers, and the lymphomas associated to metabolic disorders/diseases, which have been received less attention previously. Further, we also review the data of coexistence of lymphomas and hepatocellular carcinoma (HCC) in patients with infection of hepatitis C virus and hepatitis B virus.

Cynapanoside A exerts protective effects against obesity-induced diabetic nephropathy through ameliorating TRIM31-mediated inflammation, lipid synthesis and fibrosis

Obesity is a major predictive factor for the diabetic nephropathy (DN). However, the precise mechanism and therapeutic approach still require to be investigated. Cynapanosides A (CPS-A) is a glycoside derived from the Chinese drug Cynanchum paniculatum that has numerous pharmacological activities, but its regulatory function on obesity-induced kidney disease is still obscure. In the present study, we attempted to explore the renoprotective effects of CPS-A on the established DN in high fat diet (HFD)-fed mice, and the underlying mechanisms. We initially found that CPS-A significantly ameliorated the obesity and metabolic syndrome in mice with HFD feeding. Mice with HFD-induced DN exerted renal dysfunctions, indicated by the elevated functional parameters, including up-regulated blood urea nitrogen (BUN), urine albumin and creatinine, which were significantly attenuated by CPS-A in obese mice. Moreover, histological changes including glomerular enlargement, sclerosis index and collagen deposition in kidney of obese mice were detected, while being strongly ameliorated by CPS-A. Additionally, podocyte loss induced by HFD was also markedly mitigated in mice with CPS-A supplementation. HFD feeding also led to lipid deposition and inflammatory response in renal tissues of obese mice, whereas being considerably attenuated after CPS-A consumption. Intriguingly, we found that tripartite motif-containing protein 31 (TRIM31) signaling might be a crucial mechanism for CPS-A to perform its renoprotective functions in mice with DN. The anti-inflammatory, anti-fibrotic and anti-dyslipidemia capacities of CPS-A were confirmed in the mouse podocytes under varying metabolic stresses, which were however almost abolished upon TRIM31 ablation. These data elucidated that TRIM31 expression was largely required for CPS-A to perform its renoprotective effects. Collectively, our study is the first to reveal that CPS-A may be a promising therapeutic strategy for the treatment of obesity-induced DN or associated kidney disease.