Salt Induces Adipogenesis/Lipogenesis and Inflammatory Adipocytokines Secretion in Adipocytes

24-h urinary sodium and potassium excretions, plasma metabolomic profiles, and cardiometabolic biomarkers in the United States adults: a cross-sectional study

BACKGROUND

High-sodium and low-potassium intakes are associated with a higher risk of hypertension and cardiovascular disease, but there are limited data on the circulating metabolomics profiles of 24-h urinary sodium and potassium excretions in free-living individuals.

OBJECTIVES

We aimed to characterize the metabolomics signatures of a high-sodium and low-potassium diet in a cross-sectional study.

METHODS

In 1028 healthy older adults from the Women's and Men's Lifestyle Validation Studies, we investigated the association of habitual sodium and potassium intakes measured by 2 to 4 24-h urine samples with plasma metabolites (quantified using liquid chromatography-tandem mass spectrometry) and metabolomic pathways. Our primary exposures were energy-adjusted 24-h urinary sodium excretion, potassium excretion, and sodium-to-potassium ratio, calculated based on energy expenditure derived from the doubly labeled water method. We then assessed the partial correlations of their metabolomics scores, derived from elastic net regressions, with cardiometabolic biomarkers.

RESULTS

Higher sodium excretion was associated with 38 metabolites including higher piperine, phosphatidylethanolamine, and C5:1 carnitine. In pathway analysis, higher sodium excretion was associated with enhanced biotin and propanoate metabolism and enhanced degradation of lysine and branched-chain amino acids (BCAAs). Metabolites associated with higher potassium and lower sodium-to-potassium ratio included quinic acid and proline-betaine. After adjusting for confounding factors, the metabolomics score for sodium-to-potassium ratio positively correlated with fasting insulin (Spearman's rank correlation coefficient ρ = 0.27), C-peptide (ρ = 0.30), and triglyceride (ρ = 0.46), and negatively with adiponectin (ρ = -0.40), and high-density lipoprotein cholesterol (ρ = -0.42).

CONCLUSIONS

We discovered metabolites and metabolomics pathways associated with a high-sodium diet, including metabolites related to biotin, propanoate, lysine, and BCAA pathways. The metabolomics signature for a higher sodium low-potassium diet is associated with multiple components of elevated cardiometabolic risk.

Targeting SIK3 to modulate hippocampal synaptic plasticity and cognitive function by regulating the transcription of HDAC4 in a mouse model of Alzheimer's disease

Cognitive deterioration and memory decline associated with the progression of Alzheimer's disease (AD) primarily results from synaptic failure. However, current understanding of the upstream regulatory mechanisms controlling synaptic plasticity remains limited. Salt-inducible kinase 3 (SIK3) is central to the signal pathway and is involved in neuronal regulation of sleep duration in mice. We speculated that the SIK3 cascade signaling pathway might contribute to the pathogenesis of AD. Thus, the present study employed AD transgenic mouse models, Morris Water Maze, virus-mediated gene transfer, electrophysiology, co-immunoprecipitation, western blotting, quantitative polymerase chain reaction, immunofluorescence, ChIP-qPCR, Golgi-Cox staining and dendritic spine analysis to investigate this connection. Our results revealed that SIK3 mRNA/protein expression was significantly reduced in middle-aged AD transgenic mouse models and AD patients. Conditional deletion of SIK3 gene in dorsal hippocampal neurons of 5×FAD mice further accelerated cognitive deterioration and impaired synaptic plasticity. In hippocampal neuronal cultures, SIK3 formed a complex with HDAC4, directly phosphorylated HDAC4 and regulated its nuclear cytoplasmic shuttle. Overexpression of SIK3 could facilitate the expression of synaptic plasticity-related genes by directly repressing mef2c or involving the recruitment of histone deacetylase to promoter regions of target genes through regulation of p-HDAC4, and vice versa. Moreover, up-regulation of SLP-S, the truncated fragment of SIK3, in dorsal hippocampal neurons, restored the synaptic plasticity and alleviates the cognitive impairment in 5×FAD mice. Collectively, these findings revealed a novel and important role of SIK3-HDAC4 regulation of synaptic plasticity and propose a new target for therapeutic approaches of cognitive deficits associated with AD.

The inhibitory effects of Xiao-Gao-Jiang-Zhuo-containing serum on adipogenesis in 3T3-L1 preadipocytes

BACKGROUND

Obesity and related metabolic diseases are becoming a worldwide epidemic, leading to increased mortality and heavy medical costs. Our Chinese herbal formula Xiao-Gao-Jiang-Zhuo (XGJZ) has remarkable effects on curing obese patients in the clinic, but the cellular and molecular basis remains unknown. This study aimed to reveal the molecular mechanism involved in adipogenesis in vitro.

METHODS

Chinese herbal formula XGJZ-containing serum was prepared from XGJZ-treated obesity model rats. The function of XGJZ-containing serum was validated in 3T3-L1 preadipocytes. Oil O staining was performed to determine intracellular lipid accumulation in differentiated 3T3-L1 cells. The expression of pro-adipogenic transcription factors was measured to further validate the adipogenesis of 3T3-L1 adipocytes. The contents of triglyceride (TG), free fatty acid (FFA), and glycerin, along with the activities of lipid metabolism-related enzymes (including FAT, FATP1, DGAT, GPAT, ATGL, and HSL) were measured to study the lipogenesis in 3T3-L1 adipocytes.

RESULTS

XGJZ-containing serum inhibited 3T3-L1 differentiation, decreased intracellular lipid accumulation, and suppressed the expression of pro-adipogenic transcription factors in differentiated 3T3-L1 cells. The contents of TG, FFA, and glycerin were decreased when treated with XGJZ-containing serum, which also modulated lipid metabolism-related enzyme activities. The activities of fatty acid transporters (FAT, FATP1) and lipid mobilization enzymes (ATGL, HSL) were promoted, while activities of triglyceride biosynthesis enzymes (DGAT, GPAT) were attenuated in differentiated 3T3-L1 cells.

CONCLUSION

XGJZ-containing serum has inhibitory effects on adipogenesis in 3T3-L1 preadipocytes, affirming the effect of XGJZ in treating obesity. It provides evidence for the mechanism of obesity.

Hepatic Transcriptomics Reveals Reduced Lipogenesis in High-Salt Diet Mice

It has been demonstrated that a high salt diet (HSD) increases the risk of cardiovascular disease and metabolic dysfunction. In particular, the impact and molecular mechanisms of long-term HSD on hepatic metabolism remain largely unknown. To identify differentially expressed genes (DEGs) affecting the metabolism of liver tissues from HSD and control groups, a transcriptome analysis of liver tissues was performed in this study. As a result of the transcriptome analysis, the expression of genes related to lipid and steroid biosynthesis (such as Fasn, Scd1, and Cyp7a1) was significantly reduced in the livers of HSD mice. Additionally, several gene ontology (GO) terms have been identified as associated with metabolic processes in the liver, including the lipid metabolic process (GO: 0006629) and the steroid metabolic process (GO: 0008202). An additional quantitative RT-qPCR analysis was conducted to confirm six down-regulated genes and two up-regulated genes. Our findings provide a theoretical basis for further investigation of HSD-induced metabolic disorders.

The association between dietary sodium intake and obesity in adults by sodium intake assessment methods: a review of systematic reviews and re-meta-analysis

BACKGROUND/OBJECTIVES

The scientific evidence of a sodium-obesity association is limited by sodium intake assessments. Our specific aim is to synthesize the association between dietary sodium intake and obesity across the sodium intake assessments as evidenced by systematic reviews in adults.

SUBJECTS/METHODS

A systematic search identified systematic reviews comparing the association of dietary sodium intakes with obesity-related outcomes such as body mass index (BMI), body weight, waist circumference, and risk of (abdominal) obesity. We searched PubMed on October 24, 2022. To assess the Risk of Bias in Systematic Reviews (ROBIS), we employed the ROBIS tool.

RESULTS

This review included 3 systematic reviews, consisting of 39 unique observational studies (35 cross-sectional studies and 4 longitudinal studies) and 15 randomized controlled trials (RCTs). We found consistently positive associations between dietary sodium intake and obesity-related outcomes in cross-sectional studies. Studies that used 24-h urine collection indicated a greater BMI for those with higher sodium intake (mean difference = 2.27 kg/m2; 95% confidence interval [CI], 1.59-2.51; P < 0.001; I2 = 77%) compared to studies that used spot urine (mean difference = 1.34 kg/m2; 95% CI, 1.13-1.55; P < 0.001; I2 = 95%) and dietary methods (mean difference = 0.85 kg/m2; 95% CI, 0.1-1.51; P < 0.05; I2 = 95%).

CONCLUSIONS

Quantitative synthesis of the systematic reviews has shown that cross-sectional associations between dietary sodium intake and obesity outcomes were substantially different across the sodium intake assessments. We need more high-quality prospective cohort studies and RCTs using 24-h urine collection to examine the causal effects of sodium intake on obesity.

Pathogenesis of Hypertension in Metabolic Syndrome: The Role of Fructose and Salt

Metabolic syndrome is manifested by visceral obesity, hypertension, glucose intolerance, hyperinsulinism, and dyslipidemia. According to the CDC, metabolic syndrome in the US has increased drastically since the 1960s leading to chronic diseases and rising healthcare costs. Hypertension is a key component of metabolic syndrome and is associated with an increase in morbidity and mortality due to stroke, cardiovascular ailments, and kidney disease. The pathogenesis of hypertension in metabolic syndrome, however, remains poorly understood. Metabolic syndrome results primarily from increased caloric intake and decreased physical activity. Epidemiologic studies show that an enhanced consumption of sugars, in the form of fructose and sucrose, correlates with the amplified prevalence of metabolic syndrome. Diets with a high fat content, in conjunction with elevated fructose and salt intake, accelerate the development of metabolic syndrome. This review article discusses the latest literature in the pathogenesis of hypertension in metabolic syndrome, with a specific emphasis on the role of fructose and its stimulatory effect on salt absorption in the small intestine and kidney tubules.

Pathophysiology of cellulite: Possible involvement of selective endotoxemia

The most relevant hallmarks of cellulite include a massive protrusion of superficial adipose tissue into the dermis, reduced expression of the extracellular glycoprotein fibulin-3, and an unusually high presence of MUSE cells in gluteofemoral white adipose tissue (gfWAT) that displays cellulite. Also typical for this condition is the hypertrophic nature of the underlying adipose tissue, the interaction of adipocytes with sweat glands, and dysfunctional lymph and blood circulation as well as a low-grade inflammation in the areas of gfWAT affected by cellulite. Here, we propose a new pathophysiology of cellulite, which connects this skin condition with selective accumulation of endogenous lipopolysaccharides (LPS) in gfWAT. The accumulation of LPS within a specific WAT depot has so far not been considered as a possible pathophysiological mechanism triggering localized WAT modifications, but may very well be involved in conditions such as cellulite and, secondary to that, lipedema.

SPRY4 promotes adipogenic differentiation of human mesenchymal stem cells through the MEK-ERK1/2 signaling pathway

Obesity is a chronic metabolic disorder characterized by the accumulation of excess fat in the body. Preventing and controlling obesity by inhibiting the adipogenic differentiation of mesenchymal stem cells (MSCs) and thereby avoiding the increase of white adipose tissue is safe and effective. Recent studies have demonstrated that Sprouty proteins (SPRYs) are involved in cell differentiation and related diseases. However, the role and mechanism of SPRY4 in MSC adipogenic differentiation remain to be explored. Here, we found that SPRY4 positively correlates with the adipogenic differentiation of human adipose-derived MSCs (hAMSCs). Via gain- and loss-of-function experiments, we demonstrated that SPRY4 promotes hAMSC adipogenesis both in vitro and in vivo. Mechanistically, SPRY4 functioned by activating the MEK-ERK1/2 pathway. Our findings provide new insights into a critical role for SPRY4 as a regulator of adipogenic differentiation, which may illuminate the underlying mechanisms of obesity and suggest the potential of SPRY4 as a novel treatment option.

Title: p38δ Regulates IL6 Expression Modulating ERK Phosphorylation in Preadipocytes

IL6 is an essential cytokine in metabolism regulation and for intercommunication among different organs and tissues. IL6 produced by different tissues has different functions and therefore it is very important to understand the mechanism of its expression in adipose tissue. In this work we demonstrated that IL6 expression in mouse preadipocytes, like in human, is partially dependent on Wnt5a and JNK. Using mouse preadipocytes lacking each one of the p38 SAPK family members, we have shown that IL6 expression is also p38γ and p38δ dependent. In fact, the lack of some of these two kinases increases IL6 expression without altering that of Wnt5a. Moreover, we show that the absence of p38δ promotes greater ERK1/2 phosphorylation in a MEK1/2 independent manner, and that this increased ERK1/2 phosphorylation state is contributing to the higher IL6 expression in p38δ^−/- preadipocytes. These results suggest a new crosstalk between two MAPK signaling pathway, p38δ and ERK1/2, where p38δ modulates the phosphorylation state of ERK1/2.

High Estimated 24-Hour Urinary Sodium Excretion Is Related to Symptomatic Knee Osteoarthritis: A Nationwide Cross-Sectional Population-Based Study

OBJECTIVES

High salt intake results in various harmful effects on human health including hypertension, cardiovascular disease, and reduced bone density. Despite this, there are very few studies in the literature that have investigated the association between sodium intake and osteoarthritis (OA). Therefore, we aimed to explore these associations in a Korean population.

METHODS

This study used cross-sectional data from adult subjects aged 50-75 years from two consecutive periods of the Korean National Health and Nutrition Examination Survey V-VII (2010-2011 and 2014-2016). The estimated 24-hour urinary sodium excretion (24HUNa) was used as a surrogate marker of salt intake. In the 2010-2011 dataset, knee OA (KOA) was defined as the presence of the radiographic features of OA and knee pain. The association between KOA and salt intake was analysed using univariable and multivariable logistic regression methods. For the sensitivity analysis, the same procedures were conducted on subjects with self-reported OA (SR-OA) with knee pain in the 2010-2011 dataset and any site SR-OA in the 2014-2016 dataset.

RESULTS

Subjects with KOA had significantly lower energy intake, but higher 24HUNa than those without KOA. The restricted cubic spline plots demonstrated a J-shaped distribution between 24HUNa and prevalent KOA. When 24HUNa was stratified into five groups (<2, 2-3, 3-4, 4-5 and ≥5 g/day), subjects with high sodium intake (≥5 g/day) had a higher risk of KOA (odds ratio [OR] = 1.64, 95% confidence interval [CI] 1.03-2.62) compared to the reference group (3-4 g/day) after adjusting for covariates. The sensitivity analysis based on SR-OA with knee pain showed that high sodium intake was also significantly associated with increased prevalence of OA (OR = 1.84, 95% CI 1.10-3.10) compared with the reference group. Regarding SR-OA at any site in the 2014-2016 dataset, estimated 24HUNa showed a significantly positive association with the presence of SR-OA after adjusting for potential confounders.

CONCLUSIONS

This nationwide Korean representative study showed a significant association between symptomatic KOA and high sodium intake (≥5 g/day). Avoidance of a diet high in salt might be beneficial as a non-pharmacologic therapy for OA.

Cisplatin's potential for type 2 diabetes repositioning by inhibiting CDKN1A, FAS, and SESN1

Cisplatin is a DNA-damaging chemotherapeutic agent used for treating cancer. Based on cDNA dataset analysis, we investigated how cisplatin modified gene expression and observed cisplatin-induced dysregulation and system-level variations relating to insulin resistance and type 2 diabetes mellitus (T2DM). T2DM is a multifactorial disease affecting 462 million people in the world, and drug-induced T2DM is a serious issue. To understand this etiology, we designed an integrative, system-level study to identify associations between cisplatin-induced differentially expressed genes (DEGs) and T2DM. From a list of differential expressed genes, cisplatin downregulated the cyclin-dependent kinase inhibitor 1 (CDKN1A), tumor necrosis factor (FAS), and sestrin-1 (SESN1) genes responsible for modifying signaling pathways, including the p53, JAK-STAT, FOXO, MAPK, mTOR, P13-AKT, Toll-like receptor (TLR), adipocytokine, and insulin signaling pathways. These enriched pathways were expressively associated with the disease. We observed significant gene signatures, including SMAD3, IRS, PDK1, PRKAA1, AKT, SOS, RAS, GRB2, MEK1/2, and ERK, interacting with source genes. This study revealed the value of system genetics for identifying the cisplatin-induced genetic variants responsible for the progression of T2DM. Also, by cross-validating gene expression data for T2DM islets, we found that downregulating IRS and PRK families is critical in insulin and T2DM signaling pathways. Cisplatin, by inhibiting CDKN1A, FAS, and SESN1, promotes IRS and PRK activity in a similar way to rosiglitazone (a popular drug used for T2DM treatment). Our integrative, network-based approach can help in understanding the drug-induced pathophysiological mechanisms of diabetes.

Sodium status is associated with type 2 diabetes mellitus: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between sodium intake and the risk of developing type 2 diabetes mellitus (T2DM) is inconsistent. We, therefore, aimed to summarize the current evidence by conducting a systematic review and meta-analysis of observational studies.

METHODS

We retrieved studies which compared any marker of sodium status between individuals with T2DM and those without diabetes published in any language by searching online databases from inception up to June 2019. Summary effects were derived using random-effects model.

RESULTS

A total of 44 studies with 503,830 participants from 25 countries were included in this study. Sodium status was significantly different between individuals with and without T2DM (Hedges' g = 0.21; 95% CI 0.02, 0.40; P = 0.029). Individuals with T2DM had higher sodium intake compared to non-diabetic controls (WMD = 621.79 mg/day; 95% CI 321.53, 922.06; P < 0.001) and 24-h urinary excretion was associated with likelihood of developing T2DM (OR = 1.27, 95% CI 1.15, 1.41; P < 0.001). Furthermore, salivary, hair, and platelet sodium were higher in patients with T2DM compared to controls (P < 0.05).

CONCLUSION

The findings of the current meta-analysis suggest that sodium levels are higher in patients with T2DM compared to non-diabetic controls; however, given that these studies are observational, it is not possible to infer causality.

Beiging Modulates Inflammatory Adipogenesis in Salt-Treated and MEK6-Transfected Adipocytes

To investigate whether the beiging process changes the interactive effects of salt and MEK6 gene on inflammatory adipogenesis, the salt treatment (NaCl 50 mM) and MEK6 transfection of Tg^(+/+) cells were performed with white adipocytes (WAT) and beige-like-adipocytes (BLA). BLA induced by T3 were confirmed by UCP-1 expression and the MEK6 protein was 3.5 times higher in MEK6 transfected WAT than the control. The adipogenic genes, PPAR-γ and C/EBP-α, were 1.5 times more highly expressed in the salt-treated groups than the non-salt-treated groups, and adipogenesis was greatly increased in Tg^(+/+) WAT compared to non-transfected Tg^(−/−). The adipogenesis induced by salt treatment and MEK6 transfection was significantly reduced in BLA. The inflammatory adipocytokines, TNF-α, IL-1β, and IL-6, were increased in the salt-treated Tg^(+/+) WAT, but an anti-inflammation biomarker, the adiponectin/leptin ratio, was reduced in Tg^(+/+), to tenth of that in Tg^(−/−). However, the production of adipocytokines in WAT was strongly weakened in BLA, although a combination of salt and MEK6 transfection had the most significant effects on inflammation in both WAT and BLA. Oxygen consumption in mitochondria was maximized in salt-treated and MEK6 transfected WAT, but it was decreased by 50% in BLA. In conclusion, beiging controls the synergistic effects of salt and MEK6 on adipogenesis, inflammation, and energy expenditure.

Chinese Traditional Fermented Soy Sauce Exerts Protective Effects against High-Fat and High-Salt Diet-Induced Hypertension in Sprague-Dawley Rats by Improving Adipogenesis and Renin-Angiotensin-Aldosterone System Activity

Although high-fat and high-salt diets are considered risk factors for hypertension, the intake of salty soybean-based fermented foods has beneficial effects. This study explored the potential of Chinese traditional fermented soy sauce (CTFSS) in preventing hypertension by analyzing its effects on adipogenesis and the renin-angiotensin-aldosterone system (RAAS). Male Sprague-Dawley (SD) rats were divided into four groups (n = 6): normal diet (ND), high-fat diet (HD), high-fat diet with saline (HDS, NaCl-8%), and high-fat diet with Chinese traditional soy sauce (HDCTS, NaCl-8%). Each group is administrated 12 weeks by oral gavage as 10 mL/kg dose, respectively. CTFSS supplementation resulted in significantly lower body weight, epididymal fat weight, and systolic blood pressure. Additionally, it decreased the serum total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), renin, angiotensin II (Ang II), angiotensin-converting enzyme (ACE), and aldosterone levels. It also increased the urinary volume and improved sodium and potassium ion balance. The gene levels showed significant enhancements in the mRNA levels of renin-angiotensin-aldosterone system-related and adipogenesis-related genes. In addition, CTFSS may prevent hypertension-associated kidney injury. Therefore, this study demonstrates that CTFSS has no harmful effects on hypertension. In contrast, the beneficial effects of CTFSS intake in ameliorating hypertension were shown.

Association of Usual Sodium Intake with Obesity Among US Children and Adolescents, NHANES 2009-2016

OBJECTIVE

The purpose of this study was to investigate the association of sodium intake with obesity in US children and adolescents.

METHODS

Cross-sectional data were analyzed for 9,026 children and adolescents in the National Health and Nutrition Examination Survey (NHANES) 2009-2016. Usual sodium intake was estimated from 24-hour dietary recalls using a measurement error model. Logistic regression was used to assess the association of sodium intake with overweight/obesity, obesity, and central obesity (waist to height ratio [WtHR] ≥ 0.5; waist circumferences (WC) ≥ age- and sex-specific 90th percentile).

RESULTS

Mean (SE) sodium intake was 3,010  (9) and 3,404  (20) mg/d for children and adolescents, respectively. The adjusted odds ratio (AOR) comparing Q4 versus Q1 (87.5th vs. 12.5th percentile of sodium intake) among children was 1.98 (95% CI: 1.19-3.28) for overweight/obesity, 2.20 (1.30-3.73) for obesity, 2.10 (1.12-3.95) for WC ≥ 90th percentile, and 1.68 (0.95-2.97) for WtHR ≥ 0.5, adjusting for demographics, energy, and sugar-sweetened beverage intake. Among adolescents, AOR was 1.81 (0.98-3.37) for overweight/obesity, 1.71 (0.82-3.56) for obesity, 1.62 (0.71-3.66) for WC ≥ 90th percentile, and 1.73 (0.85-3.50) for WtHR ≥ 0.5.

CONCLUSIONS

Sodium intake was positively associated with overweight/obesity, obesity, and central obesity among US children independent of energy and SSB intake, but the association did not reach significance among adolescents.

Mineralocorticoid receptors in the pathogenesis of insulin resistance and related disorders: from basic studies to clinical disease

Aldosterone is a steroid hormone that regulates blood pressure and cardiovascular function by acting on renal and vascular mineralocorticoid receptors (MRs) to promote sodium retention and modulate endothelial function. Indeed, MRs are expressed in endothelial cells, vascular smooth muscle cells, adipocytes, immune cells, skeletal muscle cells, and cardiomyocytes. Excessive aldosterone and associated MR activation impair insulin secretion, insulin metabolic signaling to promote development of diabetes, and the related cardiometabolic syndrome. These adverse effects of aldosterone are mediated, in part, via increased inflammation, oxidative stress, dyslipidemia, and ectopic fat deposition. Therefore, inhibition of MR activation may have a beneficial effect in prevention of impaired insulin metabolic signaling, type 2 diabetes, and cardiometabolic disorders. This review highlights findings from the recent surge in research regarding MR-related cardiometabolic disorders as well as our contemporary understanding of the detrimental effects of excess MR activation on insulin metabolic signaling.

Causal associations between urinary sodium with body mass, shape and composition: a Mendelian randomization study

Observational studies have found associations between urinary sodium (UNa) with obesity, body shape and composition; but the findings may be biased by residual confounding. The objective of this two-sample Mendelian randomization (MR) study was to analyze their causal associations in both sex-combined and sex-specific models. Genome-wide association studies of UNa, body mass index (BMI), BMI-adjusted waist-to-hip ratio (WHR), body fat (BF) percentage and estimated glomerular filtration rate (eGFR) were identified. We initially extracted fifty SNPs associated with UNa at significance level of 5 × 10^–8, but further removed those SNPs with potential horizontal pleiotropy. Univariable and multivariable MR with adjustment for eGFR were performed. Inverse-variance weighted MR was performed as the primary analysis, with MR-Egger methods as sensitivity analysis. The potential bidirectional association between BMI and UNa was investigated. All exposure and outcomes were continuous, and the effect measure was regression coefficients (beta) and their 95% confidence intervals (95% CI). The total sample size was up to 322 154. UNa was causally associated with increased BMI in both men [eGFR-adjusted beta 0.443 (0.163–0.724)] and women [0.594 (0.333–0.855)]. UNa caused BF percentage increase in men [0.622 (0.268–0.976)] and women [0.334 (0.007–0.662)]. UNa significantly elevated BMI-adjusted WHR in men [0.321 (0.094–0.548)], but not in women [0.170 (− 0.052 to 0.391)]. Additionally, we found that BMI causally increased UNa [0.043 (0.023–0.063)]. UNa increased BMI and BF percentage. Salt intake affects male body shape by increasing BMI-adjusted WHR, but showed no effects on female body shape. The bidirectional association between BMI and UNa suggested that salt reduction measures and weight reduction measures should be implemented simultaneously to break the vicious cycle and gain more health benefits.

Murine in vitro cellular models to better understand adipogenesis and its potential applications

Adipogenesis has been extensively studied using in vitro models of cellular differentiation, enabling long-term regulation of fat cell metabolism in human adipose tissue (AT) material. Many studies promote the idea that manipulation of this process could potentially reduce the prevalence of obesity and its related diseases. It has now become essential to understand the molecular basis of fat cell development to tackle this pandemic disease, by identifying therapeutic targets and new biomarkers. This review explores murine cell models and their applications for study of the adipogenic differentiation process in vitro. We focus on the benefits and limitations of different cell line models to aid in interpreting data and selecting a good cell line model for successful understanding of adipose biology.

Hypertonic saline mediates the NLRP3/IL-1β signaling axis in microglia to alleviate ischemic blood-brain barrier permeability by downregulating astrocyte-derived VEGF in rats

Introduction

The aim of this study was to explore whether the antibrain edema of hypertonic saline (HS) is associated with alleviating ischemic blood‐brain barrier (BBB) permeability by downregulating astrocyte‐derived vascular endothelial growth factor (VEGF), which is mediated by microglia‐derived NOD‐like receptor protein 3 (NLRP3) inflammasome.

Methods

The infarct volume and BBB permeability were detected. The protein expression level of VEGF in astrocytes in a transient focal brain ischemia model of rats was evaluated after 10% HS treatment. Changes in the NLRP3 inflammasome, IL‐1β protein expression, and the interleukin‐1 receptor (IL1R1)/pNF‐кBp65/VEGF signaling pathway were determined in astrocytes.

Results

HS alleviated the BBB permeability, reduced the infarct volume, and downregulated the expression of VEGF in astrocytes. HS downregulates IL‐1β expression by inhibiting the activation of the NLRP3 inflammasome in microglia and then downregulates VEGF expression by inhibiting the phosphorylation of NF‐кBp65 mediated by IL‐1β in astrocytes.

Conclusions

HS alleviated the BBB permeability, reduced the infarct volume, and downregulated the expression of VEGF in astrocytes. HS downregulated IL‐1β expression via inhibiting the activation of the NLRP3 inflammasome in microglia and then downregulated VEGF expression through inhibiting the phosphorylation of NF‐кBp65 mediated by IL‐1β in astrocytes.

The malignancy of liver cancer cells is increased by IL-4/ERK/AKT signaling axis activity triggered by irradiated endothelial cells

The malignant traits involved in tumor relapse, metastasis and the expansion of cancer stem-like cells are acquired via the epithelial-mesenchymal transition (EMT) process in the tumor microenvironment. In addition, the tumor microenvironment strongly supports the survival and growth of malignant tumor cells and further contributes to the reduced efficacy of anticancer therapy. Ionizing radiation can influence the tumor microenvironment, because it alters the biological functions of endothelial cells composing tumor vascular systems. However, to date, studies on the pivotal role of these endothelial cells in mediating the malignancy of cancer cells in the irradiated tumor microenvironment are rare. We previously evaluated the effects of irradiated endothelial cells on the malignant traits of human liver cancer cells and reported that endothelial cells irradiated with 2 Gy reinforce the malignant properties of these cancer cells. In this study, we investigated the signaling mechanisms underlying these events. We revealed that the increased expression level of IL-4 in endothelial cells irradiated with 2 Gy eventually led to enhanced migration and invasion of cancer cells and further expansion of cancer stem-like cells. In addition, this increased level of IL-4 activated the ERK and AKT signaling pathways to reinforce these events in cancer cells. Taken together, our data indicate that ionizing radiation may indirectly modulate malignancy by affecting endothelial cells in the tumor microenvironment. Importantly, these indirect effects on malignancy are thought to offer valuable clues or targets for overcoming the tumor recurrence after radiotherapy.

Genes and Eating Preferences, Their Roles in Personalized Nutrition

At present, personalized diets, which take into account consumer genetic characteristics, are growing popular. Nutrigenetics studies the effect of gene variations on metabolism and nutrigenomics, which branches off further and investigates how nutrients and food compounds affect genes. This work deals with the mutations affecting the assimilation of metabolites, contributing to nutrigenetic studies. We searched for the genes responsible for eating preferences which allow for the tailoring of personalized diets. Presently, genetic nutrition is growing in demand, as it contributes to the prevention and/or rehabilitation of non-communicable diseases, both monogenic and polygenic. In this work, we showed single-nucleotide polymorphisms in genes-missense mutations that change the functions of coded proteins, resulting in a particular eating preferences or a disease. We studied the genes influencing food preferences-particularly those responsible for fats and carbohydrates absorption, food intolerance, metabolism of vitamins, taste sensations, oxidation of xenobiotics, eating preferences and food addiction. As a result, 34 genes were identified that affect eating preferences. Significant shortcomings were found in the methods/programs for developing personalized diets that are used today, and the weaknesses were revealed in the development of nutrigenetics (inconsistency of data on SNP genes, ignoring population genetics data, difficult information to understand consumer, etc.). Taking into account all the shortcomings, an approximate model was proposed in the review for selecting an appropriate personalized diet. In the future, it is planned to develop the proposed model for the compilation of individual diets.

Higher Sodium Intake Assessed by 24 Hour Urinary Sodium Excretion Is Associated with Non-Alcoholic Fatty Liver Disease: The PREVEND Cohort Study

A higher sodium intake is conceivably associated with insulin resistant conditions like obesity, but associations of non-alcoholic fatty liver disease (NAFLD) with a higher sodium intake determined by 24 hours (24 h) urine collections are still unclear. Dietary sodium intake was measured by sodium excretion in two complete consecutive 24 h urine collections in 6132 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. Fatty Liver Index (FLI) ≥60 and Hepatic Steatosis Index (HSI) >36 were used as proxies of suspected NAFLD. 1936 (31.6%) participants had an FLI ≥60, coinciding with the increased prevalence of type 2 diabetes (T2D), metabolic syndrome, hypertension and history of cardiovascular disease. Sodium intake was higher in participants with an FLI ≥60 (163.63 ± 61.81 mmol/24 h vs. 136.76 ± 50.90 mmol/24 h, p < 0.001), with increasing incidence in ascending quartile categories of sodium intake (p < 0.001). Multivariably, an FLI ≥60 was positively associated with a higher sodium intake when taking account for T2D, a positive cardiovascular history, hypertension, alcohol intake, smoking and medication use (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.44–1.64, p < 0.001). Additional adjustment for the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) diminished this association (OR 1.30, 95% CI 1.21–1.41, p < 0.001). HSI >36 showed similar results. Associations remained essentially unaltered after adjustment for body surface area or waist/hip ratio. In conclusion, suspected NAFLD is a feature of higher sodium intake. Insulin resistance-related processes may contribute to the association of NAFLD with sodium intake.

Inter-organ cross-talk in metabolic syndrome

Maintenance of systemic homeostasis and the response to nutritional and environmental challenges require the coordination of multiple organs and tissues. To respond to various metabolic demands, higher organisms have developed a system of inter-organ communication through which one tissue can affect metabolic pathways in a distant tissue. Dysregulation of these lines of communication contributes to human pathologies, including obesity, diabetes, liver disease and atherosclerosis. In recent years, technical advances such as data-driven bioinformatics, proteomics and lipidomics have enabled efforts to understand the complexity of systemic metabolic cross-talk and its underlying mechanisms. Here, we provide an overview of inter-organ signals and their roles in metabolic control, and highlight recent discoveries in the field. We review peptide, small-molecule and lipid mediators secreted by metabolic tissues, as well as the role of the central nervous system in orchestrating peripheral metabolic functions. Finally, we discuss the contributions of inter-organ signalling networks to the features of metabolic syndrome.

The complex genetics and biology of human temperament: a review of traditional concepts in relation to new molecular findings

Recent genome-wide association studies (GWAS) have shown that temperament is strongly influenced by more than 700 genes that modulate associative conditioning by molecular processes for synaptic plasticity and long-term learning and memory. The results were replicated in three independent samples despite variable cultures and environments. The identified genes were enriched in pathways activated by behavioral conditioning in animals, including the two major molecular pathways for response to extracellular stimuli, the Ras-MEK-ERK and the PI3K-AKT-mTOR cascades. These pathways are activated by a wide variety of physiological and psychosocial stimuli that vary in positive and negative valence and in consequences for health and survival. Changes in these pathways are orchestrated to maintain cellular homeostasis despite changing conditions by modulating temperament and its circadian and seasonal rhythms. In this review we first consider traditional concepts of temperament in relation to the new genetic findings by examining the partial overlap of alternative measures of temperament. Then we propose a definition of temperament as the disposition of a person to learn how to behave, react emotionally, and form attachments automatically by associative conditioning. This definition provides necessary and sufficient criteria to distinguish temperament from other aspects of personality that become integrated with it across the life span. We describe the effects of specific stimuli on the molecular processes underlying temperament from functional, developmental, and evolutionary perspectives. Our new knowledge can improve communication among investigators, increase the power and efficacy of clinical trials, and improve the effectiveness of treatment of personality and its disorders.

Hypertension as a Metabolic Disorder and the Novel Role of the Gut

Purpose of Review

Hypertension is related to impaired metabolic homeostasis and can be regarded as a metabolic disorder. This review presents possible mechanisms by which metabolic disorders increase blood pressure (BP) and discusses the importance of the gut as a novel modulator of BP.

Recent Findings

Obesity and high salt intake are major risk factors for hypertension. There is a hypothesis of “salt-induced obesity”; i.e., high salt intake may tie to obesity. Heightened sympathetic nervous system (SNS) activity, especially in the kidney and brain, increases BP in obese patients. Adipokines, including adiponectin and leptin, and renin-angiotensin-aldosterone system (RAAS) contribute to hypertension. Adiponectin induced by a high-salt diet may decrease sodium/glucose cotransporter (SGLT) 2 expression in the kidney, which results in reducing BP. High salt can change secretions of adipokines and RAAS-related components. Evidence has been accumulating linking the gastrointestinal tract to BP. Glucagon-like peptide-1 (GLP-1) and ghrelin decrease BP in both rodents and humans. The sweet taste receptor in enteroendocrine cells increases SGLT1 expression and stimulates sodium/glucose absorption. Roux-en-Y gastric bypass improves glycemic and BP control due to reducing the activity of SGLT1. Na/H exchanger isoform 3 (NHE3) increases BP by stimulating the intestinal absorption of sodium. Gastrin functions as an intestinal sodium taste sensor and inhibits NHE3 activity. Intestinal mineralocorticoid receptors also regulate sodium absorption and BP due to changing ENaC activity. Gastric sensing of sodium induces natriuresis, and gastric distension increases BP. Changes in the composition and function of gut microbiota contribute to hypertension. A high-salt/fat diet may disrupt the gut barrier, which results in systemic inflammation, insulin resistance, and increased BP. Gut microbiota regulates BP by secreting vasoactive hormones and short-chain fatty acids. BP-lowering effects of probiotics and antibiotics have been reported. Bariatric surgery improves metabolic disorders and hypertension due to increasing GLP-1 secretion, decreasing leptin secretion and SNS activity, and changing gut microbiome composition. Strategies targeting the gastrointestinal system may be therapeutic options for improving metabolic abnormalities and reducing BP in humans.

Summary

SNS, brain, adipocytes, RAAS, the kidney, the gastrointestinal tract, and microbiota play important roles in regulating BP. Most notably, the gut could be a novel target for treatment of hypertension as a metabolic disorder.