Effects of glucose ingestion on circulating inflammatory mediators: Influence of sex and weight excess

The Application of Drugs and Nano-Therapies Targeting Immune Cells in Hypoxic Inflammation

Immune cells are pivotal in the dynamic interplay between hypoxia and inflammation. During hypoxic conditions, HIF-1α, a crucial transcription factor, facilitates the adaptation of immune cells to the hypoxic micro-environment. This adaptation includes regulating immune cell metabolism, significantly impacting inflammation development. Strategies for anti-inflammatory and hypoxic relief have been proposed, aiming to disrupt the hypoxia-inflammation nexus. Research extensively focuses on anti-inflammatory agents and materials that target immune cells. These primarily mitigate hypoxic inflammation by encouraging M2-macrophage polarization, restraining neutrophil proliferation and infiltration, and maintaining Treg/TH17 balance. Additionally, oxygen-releasing nano-materials play a significant role. By alleviating hypoxia and clearing reactive oxygen species (ROS), these nano-materials indirectly influence immune cell functions. This paper delves into the response of immune cells under hypoxic conditions and the resultant effects on inflammation. It provides a comprehensive overview of various therapies targeting specific immune cells for anti-inflammatory purposes and explores nano-materials that either carry or generate oxygen to alleviate anoxic micro-environments.

Sex differences and sex steroids influence on the presentation and severity of cardiovascular autonomic neuropathy of patients with type 1 diabetes

BACKGROUND

Sex differences characterize cardiovascular outcomes in patients with type 1 diabetes. Cardioautonomic neuropathy is a common complication of type 1 diabetes that associates increased morbi-mortality. Data regarding the interplay between sex and cardiovascular autonomic neuropathy are scarce and controversial in these patients. We aimed to address sex-related differences in the prevalence of seemingly asymptomatic cardioautonomic neuropathy in type 1 diabetes, and their associations with sex steroids.

METHODS

We conducted a cross-sectional study including 322 consecutively recruited patients with type 1 diabetes. Cardioautonomic neuropathy was diagnosed using Ewing's score and power spectral heart rate data. We assessed sex hormones by liquid chromatography/tandem mass spectrometry.

RESULTS

When considering all subjects as a whole, asymptomatic cardioautonomic neuropathy prevalence was not significantly different between women and men. When age was taken into account, the prevalence of cardioautonomic neuropathy was similar among young men and those > 50 years. However, in women > 50 years, the prevalence of cardioautonomic neuropathy doubled that of young women [45.8% (32.6; 59.7) vs. 20.4% (13.7; 29.2), respectively]. The OR of having cardioautonomic neuropathy was 3.3 higher in women > 50 years than in their younger counterparts. Furthermore, women presented more severe cardioautonomic neuropathy than men. These differences were even more marked when women were classified according their menopausal status instead of age. Peri- and menopausal women had an OR 3.5 (1.7; 7.2) of having CAN compared with their reproductive-aged counterparts [CAN prevalence: 51% (37; 65) vs. 23% (16; 32), respectively]. A binary logistic regression model (R²: 0.161; P = 0.001) displayed age > 50 years as a significant determinant of cardioautonomic neuropathy only in women. Androgens were positively associated with heart rate variability in men, and negatively in women. Accordingly, cardioautonomic neuropathy was associated with increased testosterone/estradiol ratio in women but to decreased testosterone concentrations in men.

CONCLUSIONS

Menopause in women with type 1 diabetes is accompanied by an increase in the prevalence of asymptomatic cardioautonomic neuropathy. This age-related excess risk of cardioautonomic neuropathy is not observed in men. Men and women with type 1 diabetes have opposite associations between circulating androgens and indexes of cardioautonomic function. Trial registration ClinicalTrials.gov Identifier: NCT04950634.

Hyperglycemia-induced oxidative stress and epigenetic regulation of ET-1 gene in endothelial cells

Introduction: Hyperglycemia-induced endothelial dysfunction and the subsequent increase of oxidative stress could lead to aberrant regulation of various genes which are responsible for a range of functions. This study aims to find out how hyperglycemia affect oxidative stress and then the expression and methylation of endothelin 1 (ET-1) gene in in human umbilical vein endothelial cells (HUVEC). Methods: Cells were cultured in growth medium and exposed to low and high glucose concentrations to mimic normal and diabetic condition respectively. Computational analysis were performed using UCSC genome browser and eukaryotic promoter database (EPD). The expression of ET-1 gene was investigated by real time PCR. Cytotoxicity and oxidative stress were determined by MTT and DCFH-DA assays respectively. Promoter methylation was assessed by the bisulfite sequencing method. Results: DCFH-DA assay showed that hyperglycemia can significantly increase the regulation of reactive oxygen species synthesis. The relative expression of ET-1 gene was increased due to exposure to high glucose concentration. MTT assay revealed reduced viability of cells due to the glucose induced damage. Methylation analysis revealed hypomethylation of the promoter of ET-1 however the difference was not significant. Out of 175 CpGs at 25 CpG sites, only 36 CpGs were methylated (20.5% methylation) in cell treated with normal glucose. Upon exposure to high glucose only 30 CpGs were methylated in 175 CpGs at 25 CpG sites (17.1% methylation). Discussion: Our study concludes a significantly high expression of ET-1 gene in response to high glucose exposure in HUVECs. It also reports that hyperglycemic condition leads to elevated oxidative stress. No significant change was found in methylation when cells were treated with high and low glucose concentrations.

The Effects of Sex and Body Weight on Renal Graft Function-The Role of CCL2

There are reports on the effects of excessive recipient body weight on renal graft function. Increased CCL2 (chemokine CC-mortif ligand 2) production is observed in patients with excessive body weight. CCL2 also exacerbates the inflammatory process in the renal graft. A total of 49 renal graft recipients of both sexes having undergone renal biopsy within the last 18 months were retrospectively reviewed. At their most recent appointment the patients’ plasma concentrations of CCL2 were evaluated. Renal function was assessed retrospectively. CCL2 concentrations were higher in men than women (p < 0.047), while higher CCL2 levels were associated with a decrease in eGFR (estimated glomerular filtration rate) during the first year post Tx (kidney transplantation). CCL2 negatively correlated with eGFR at 5 years (R = −0.45, p < 0.040997) and positively correlated with the degree of tubular atrophy in renal biopsy specimens (R = 0.43, p < 0.027293) and with systolic pressure. Men showed significantly higher BMI (body mass index) values at the time of Tx and at their last appointment than women did (p < 0.000403; p < 0.000613, respectively). Men showed poorer long-term renal graft function, with significantly lower eGFR values at 4 and 5 years into the post-transplantation period. The male sex and excessive body weight have adverse effects on short- and long-term renal graft function, which is associated with increased levels of CCL2.

HIF-1α/JMJD1A signaling regulates inflammation and oxidative stress following hyperglycemia and hypoxia-induced vascular cell injury

Background

Endothelial cell (EC) injury accelerates the progression of diabetic macrovascular complications. Hypoxia is an important cause of EC injury. Hypoxia-inducible factor-1 alpha (HIF-1α) is an important hypoxia regulatory protein. Our previous studies showed that high-glucose and hypoxic conditions could upregulate HIF-1α expression and enhance EC inflammatory injury, independently of the nuclear factor kappa-B (NF-κB) pathway. However, it is not clear whether HIF-1α plays a role in vascular disease through epigenetic-related mechanisms.

Methods

We conducted gene expression analysis and molecular mechanistic studies in human umbilical vein endothelial cells (HUVECs) induced by hyperglycemia and hypoxia using RNA sequencing (RNA-seq) and small interfering HIF-1α (si-HIF-1α). We determined HIF-1α and Jumonji domain-containing protein 1 A (JMJD1A) expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot, analyzed inflammatory protein secretion in the cell supernatant by enzymelinked immunosorbent assay (ELISA), and assessed protein interaction between HIF-1α and JMJD1A by chromatin immunoprecipitation (Ch-IP). We used the Cell Counting Kit8 (CCK-8) assay to analyze cell viability, and assessed oxidative stress indicators by using a detection kit and flow cytometry.

Results

High glucose and hypoxia up-regulated HIF-1α expression, and down-regulated HIF-1α decreased the level of inflammation and oxidative stress in HUVECs. To determine the downstream pathways, we observed histone demethylases genes and related pathway by RNA-sEq. Among these, JMJD1A was the most upregulated gene in histone demethylases. Moreover, we observed that HIF-1α bound to the promoter of JMJD1A, and the ameliorative effects of si-HIF-1α on oxidative stress and inflammatory cytokines in high-glucose and hypoxia-induced HUVECs were reversed by JMJD1A overexpression. Furthermore, knockdown of JMJD1A decreased inflammatory and oxidative stress injury. To determine the JMJD1A-related factors, we conducted gene expression analysis on JMJD1A-knockdown HUVECs. We observed that downregulation of inflammation and the oxidative stress pathway were enriched and FOS and FOSB might be important protective transcription factors.

Conclusions

These findings provide novel evidence that the HIF-1α/JMJD1A signaling pathway is involved in inflammation and oxidative stress in HUVECs induced by high glucose and hypoxia. Also, this pathway might act as a novel regulator of oxidative stress and inflammatory-related events in response to diabetic vascular injury and thus contribute to the pathological progression of diabetes and vascular disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00283-8.

Polycystic ovary syndrome and obesity: clinical aspects and nutritional management

INTRODUCTION

Polycystic Ovary Syndrome (PCOS) is a multifactorial endocrine and metabolic disorder characterized by androgen excess, oligo-anovulatory infertility, polycystic ovaries in ultrasound examination, insulin resistance, and cardiometabolic disorders, with overweight/obesity and visceral adiposity. This review aims to provide an overview of the clinical characteristics and nutritional therapy of PCOS and obesity.

METHODS

The authors analyzed the updated and relevant publications found on Pubmed about clinical aspects and nutritional management of PCOS and obesity in studies done in animal and human models.

DISCUSSION

It is crucial an early detection and intervention in PCOS patients to avoid the more challenging control of the onset of more impaired-health conditions that this pathology causes. It is presented evidence that clearly shows the close interaction among oxidative stress, low-grade inflammation, and PCOS. It is also analyzed the relevance of treating metabolic and nutritional correlations of PCOS with a complete therapeutic strategy that includes individualized medication, diet, and healthy habits.

CONCLUSIONS

By an integral approach and treatment that includes not only medications for PCOS symptoms, supplementation of minerals and vitamins to control PCOS complications but an antiinflammatory diet, nutritional education, exercise individualized program, lifestyle changes, it is possible to improve insulin resistance, sustained weight loss, ovulation rates, among other goals for the management of this disease. Further studies are needed to clarify mechanisms, beneficial effects, and doses of supplements and precise medication to determine the best combination of diets and exercise programs according to these patients' specific requirements.

Acute-phase glycoprotein profile responses to different oral macronutrient challenges: Influence of sex, functional hyperandrogenism and obesity

Acute-phase glycoprotein ¹H-NMR spectroscopy profiles serve as surrogate markers of chronic inflammation in metabolic disorders such as obesity, diabetes and polycystic ovary syndrome (PCOS). The latter is associated with increased height-to-width (H/W) ratios of GlycA and GlycB after fasting, but not to glycoprotein areas, regardless of obesity. We studied the responses to separate glucose, lipid and protein oral challenges of five glycoprotein variables (GlycA, GlycB, and GlycF areas and the GlycA and GlycB H/W ratios) in 17 women with PCOS, 17 control women, and 19 healthy men. Glucose and protein ingestion resulted into decreases in all glycoprotein variables, whereas lipid ingestion increased GlycA, GlycF and induced minimal changes in GlycB and GlycB H/W. We found no effects of obesity or group of subjects on postprandial glycoprotein variables regardless of the macronutrient being ingested. However, a statistically significant interaction indicated that obesity blunted the decrease in some of these variables in control women and men, whereas obese women with PCOS showed larger changes when compared with their non-obese counterparts. In conclusion, acute-phase glycoprotein profiles indicate an anti-inflammatory response during postprandial phase that is less pronounced after lipid ingestion, and is counteracted by the chronic inflammatory background associated with obesity and PCOS.

TLR2 and TLR4 Surface and Gene Expression in White Blood Cells after Fasting and Oral Glucose, Lipid and Protein Challenges: Influence of Obesity and Sex Hormones

We studied if macronutrients of the diet have different effects on leukocyte activation, and if these effects are influenced by sex hormones or obesity. We analyzed leukocyte cell surface and gene expression of toll-like receptors 2 and 4 (TLR2 and TLR4) during fasting and after macronutrient loads in women with polycystic ovary syndrome and female and male controls. Fasting TLR2 surface expression in neutrophils was higher in men than in women. Obese subjects presented higher TLR2 gene expression than nonobese individuals, particularly in men. In contrast, surface TLR4 expression was lower in men and in obese individuals. Postprandial cell-surface expression decreased similarly after all macronutrient loads. Neutrophil TLR2 decreased only in obese subjects whereas TLR4 showed a greater decrease in nonobese individuals. However, TLR2 gene expression increased after glucose ingestion and decreased during the lipid load, while TLR4 was induced in response to lipids and mostly to glucose. Postprandial TLR gene expression was not influenced by group of subjects or obesity. Both cell-surface and gene postprandial expression inversely correlated with their fasting levels. These responses suggest a transient compensatory response aiming to prevent postprandial inflammation. However, obesity and sex hormones showed opposite influences on surface expression of TLR2 and TLR4, but not on their gene expression, pointing to regulatory posttranscriptional mechanisms.

Postprandial inflammatory responses after oral glucose, lipid and protein challenges: Influence of obesity, sex and polycystic ovary syndrome

BACKGROUND & AIMS

Most evidence linking the polycystic ovary syndrome (PCOS) with chronic low-grade inflammation has been obtained in the fasting state. We have studied the postprandial inflammatory response to oral glucose, lipid and protein challenges and the possible influences of obesity, sex and PCOS on these responses.

METHODS

On alternate days, we submitted 17 women with PCOS (9 non-obese, 8 obese), 17 control women (9 non-obese, 8 obese) and 19 control men (10 non-obese, 9 obese) to isocaloric (300 Kcal) oral macronutrient loads. We assayed serum for TNF-α, IL-6, IL-18, IL-10, pentraxin-3 and galectin-3 concentrations and leukocytes for expression of TNF, IL6, IL10 and their receptors TNFRSF1B, IL6R and IL10RA.

RESULTS

Circulating IL-6 levels decreased after glucose and protein ingestion but slightly increased after oral lipid intake. Leukocyte IL6 expression did not change after the ingestion of any macronutrient yet IL6R expression increased during all macronutrient challenges, the largest increase being observed after glucose ingestion. Serum TNF-α similarly decreased during either macronutrient load, whereas TNF expression increased after macronutrient ingestion, the highest increase observed after oral glucose. TNFRSF1B expression also increased after glucose intake but not after lipid or protein ingestion. No global effect of obesity or group on postprandial circulating IL-6, TNF-α, or IL6, IL6R, TNF and TNFRSF1B expression was found. Circulating IL-18 concentrations decreased during all oral challenges, whereas in case of galectin-3 and pentraxin-3 only the protein load caused a reduction in its concentrations. Of the genes studied here, IL10 showed the largest increase in expression throughout all the postprandial curves, particularly after glucose. Obesity blunted the increase in IL10 expression. IL10RA expression decreased after glucose ingestion but remained unchanged during lipid and protein loads.

CONCLUSIONS

Glucose ingestion, as opposed to lipid and protein intake, results into the largest increase in leukocyte gene expression of inflammatory mediators. The expression of the anti-inflammatory cytokine IL10 was the largest observed here, suggesting a compensatory mechanisms against postprandial inflammation that may be blunted in obesity. However, these responses did not translate into the circulating concentrations of these inflammatory mediators during the immediate postprandial phase.

Pentraxin 3 increases in adult overweight and obese men after weight loss by dietary modification with exercise training

The circulatory level of pentraxin 3 (PTX3), an anti-inflammatory cardioprotective protein, has been shown to be lower in obese individuals than in those with normal weight. However, reports on the effects of different weight-loss methods on PTX3 are limited. The present study aimed to investigate the effect of weight loss on circulating PTX3 levels in overweight and obese men and to examine the combined effect of dietary modification and exercise training on PTX3 levels. Forty-eight overweight and obese men were assigned to 2 groups: dietary modification (group D) or exercise training and dietary modification (group DE). Groups D and DE were composed of 27 and 21 participants, respectively. We observed a significant independent relationship between changes in PTX3 and body mass index (BMI) in all participants (β = -0.617, p < 0.01). Subsequently, we compared the effects of the 2 weight-loss methods on plasma PTX3 in groups D and DE. The magnitude of the increase in plasma PTX3 levels was similar in the 2 groups. Interestingly, we observed that PTX3 levels in group DE increased significantly more than those in group D in subjects who achieved normal weight, based on BMI, after interventions. Our study suggested that weight reduction after lifestyle modification significantly increased PTX3 levels in overweight and obese men, and the addition of habitual exercise to dietary modification enhanced the magnitude of the increase in PTX3 levels in obese individuals achieving normal weight after weight loss.

Aerobic fitness alters the capacity of mononuclear cells to produce pentraxin 3 following maximal exercise

PURPOSE

Pentraxin 3 (PTX3) is a vital regulator of innate immune function. Although plasma PTX3 concentrations are elevated with aerobic fitness, the cellular functions of PTX3 remain unknown in aerobically trained and untrained subjects.

METHODS

Thirty individuals (aerobically trained = 15 and untrained = 15) participated in a maximal exercise protocol to examine ex vivo PTX3 production from isolated peripheral blood mononuclear cells (PBMCs) exposed to LPS or palmitate. The capacity of PTX3 to stimulate inflammatory cytokine production ex vivo was also examined.

RESULTS

Elevated plasma PTX3 concentrations prior to exercise were positively associated with the percent change (pre to post exercise) in plasma PTX3 concentrations in all subjects, independent of cardiorespiratory fitness (VO_2max). In addition, elevated plasma PTX3 concentrations in aerobically trained subjects at rest predicted changes in the LPS- and palmitate-stimulated PTX3 production from isolated PBMCs following acute exercise. In response to PTX3 simulation, the capacity of PBMCs to produce the anti-inflammatory cytokine IL-10 was decreased following acute exercise in all subject (no changes in IL-6, TGF-β1, and TNF-α observed). However, the percent change in IL-6 production was positively associated with VO_2max in all subjects, and in aerobically trained subjects only, positively associated with elevated plasma PTX3 concentrations at rest and in response to acute exercise.

CONCLUSION

These results suggest that aerobic training enhances the utilization of plasma PTX3 concentrations to predict the capacity of mononuclear cells to produce PTX3, and potentially, its reciprocal role of PTX3 as an initiator of the innate immune response following maximal exercise.

Plasma pentraxin 3 and glucose kinetics following acute high-intensity interval exercise versus continuous moderate-intensity exercise in healthy men

Pentraxin 3 (PTX3) is mainly synthesized and released by neutrophils to help regulate innate immunity. While plasma PTX3 concentrations are associated with improved glucose metabolism and overall metabolic health, there is evidence that significant elevations in plasma glucose downregulate circulating levels of PTX3. To examine whether this relationship would be altered in response to exercise, this study investigated the kinetics of the plasma glucose and PTX3 responses following high-intensity interval exercise (HIIE) and continuous moderate-intensity exercise (CMIE). It was hypothesized that the increased concentrations of plasma glucose following HIIE compared with CMIE would be associated with an attenuated plasma PTX3 response. Eight healthy male subjects participated in both HIIE and CMIE protocols administered as a randomized, counterbalanced design. Linear mixed models for repeated measures revealed that the overall plasma glucose response was greater following HIIE compared with CMIE (protocol × time effect: p = 0.037). Although the plasma PTX3 response was higher only at 19 min into HIIE compared with CMIE (protocol × time effect: p = 0.013), no relationships were observed between plasma glucose and PTX3 either at baseline or in response to both exercise protocols, as indicated by the area under the curve "with respect to increase" analysis. Our results indicate that exercise-mediated plasma PTX3 concentrations are independent of the plasma glucose response. In addition, the present study suggests that the neutrophil-mediated innate immune response, as indicated by plasma PTX3 response, may be activated earlier during HIIE compared with CMIE.

Plasma thiobarbituric acid reactive substances (TBARS) in young adults: Obesity increases fasting levels only in men whereas glucose ingestion, and not protein or lipid intake, increases postprandial concentrations regardless of sex and obesity

SCOPE

Oxidative stress and damage participate in the pathophysiology of obesity and its metabolic complications. We studied the influence of sex, obesity, and ingestion of different macronutrients on fasting and postprandial thiobarbituric acid reactive substances (TBARS), which can be considered as an index of lipid peroxidation and oxidative damage.

METHODS AND RESULTS

We studied 19 men and 17 women, out of whom nine men and eight women had obesity. We collected blood samples in the fasting state and, on alternate days, following the ingestion of 300 kcal in the form of glucose, lipids, or proteins. Fasting TBARS concentrations correlated with waist circumference and were increased in obese men compared with nonobese men. This increase was not, however, observed in women. TBARS concentrations showed a marked increase following the ingestion of glucose in parallel to the increase in plasma glucose when considering all subjects as a whole, but did not increase after the oral intake of lipids and proteins.

CONCLUSION

Plasma TBARS concentrations are increased in the fasting state only in obese men in association with abdominal adiposity, and increases markedly after the ingestion of glucose, but not after oral intake of lipids and proteins, regardless of sex and obesity.

The Potential Role of Aerobic Exercise-Induced Pentraxin 3 on Obesity-Related Inflammation and Metabolic Dysregulation

Obesity is defined as the excess accumulation of intra-abdominal body fat, resulting in a state of chronic, low-grade proinflammation that can directly contribute to the development of insulin resistance. Pentraxin 3 (PTX3) is an acute-phase protein that is expressed by a variety of tissue and cell sources and provides an anti-inflammatory property to downregulate the production of proinflammatory cytokines, in particular interleukin-1 beta and tumor necrosis factor alpha. Although PTX3 may therapeutically aid in altering the proinflammatory milieu in obese individuals, and despite elevated expression of PTX3 mRNA observed in adipose tissue, the circulating level of PTX3 is reduced with obesity. Interestingly, aerobic activity has been demonstrated to elevate PTX3 levels. Therefore, the purpose of this review is to discuss the therapeutic potential of PTX3 to positively regulate obesity-related inflammation and discuss the proposition for utilizing aerobic exercise as a nonpharmacological anti-inflammatory treatment strategy to enhance circulating PTX3 concentrations in obese individuals.