Sex differences in systemic inflammation and immune function in diet-induced obesity rodent models: A systematic review

Understanding sex differences in immunological responses in the context of obesity is important to improve health outcomes. This systematic review aimed to investigate sex differences in systemic inflammation, immune cell phenotype, and function in diet-induced obesity (DIO) animal models. A systematic search in Medline, Embase, and CINAHL from inception to April 2023 was conducted, using a combination of the following concepts: sex, obesity, cytokines, and immune cell phenotypes/function. Forty-one publications reporting on systemic inflammation (61%), cell phenotype (44%), and/or function (7%) were included. Females had lower systemic inflammation compared with males in response to DIO intervention and a higher proportion of macrophage (M)2-like cells compared with males that had a higher proportion of M1-like in adipose tissue. Although there were no clear sex differences in immune function, high-fat DIO intervention remains an important factor in the development of immune dysfunction in both males and females, including disturbances in cytokine production, proliferation, and migration of immune cells. Yet, the mechanistic links between diet and obesity on such immune dysfunction remain unclear. Future studies should investigate the role of diet and obesity in the functionality of immune cells and employ adequate methods for a high-quality investigation of sex differences in this context.

Corrigendum: The nutrition and immunity (nutrIMM) study: protocol for a non-randomized, four-arm parallel-group, controlled feeding trial investigating immune function in obesity and type 2 diabetes

[This corrects the article DOI: 10.3389/fnut.2023.1243359.].

The nutrition and immunity (nutrIMM) study: protocol for a non-randomized, four-arm parallel-group, controlled feeding trial investigating immune function in obesity and type 2 diabetes

Introduction

Individuals with obesity and/or type 2 diabetes are at higher risk of infection and have worse prognoses compared to healthy individuals. Several factors may influence immune responses in this population, including high adiposity, hyperglycemia, and unhealthy dietary habits. However, there is insufficient data on the independent or clustered contribution of these factors to obesity-related immune dysfunction, especially accounting for dietary intake. This study aims to establish the independent contribution of obesity and hyperglycemia to immune dysfunction independent of diet in adults with and without obesity with or without type 2 diabetes.

Methods

The Nutrition and Immunity (nutrIMM) study is a single-centre, non-randomized, four-arm, parallel-group, controlled feeding trial. It will enroll adults without obesity (Lean-NG) and with obesity and three metabolic phenotypes of normoglycemia, glucose intolerance, and type 2 diabetes. Participants will be assigned to one of four groups and will consume a standard North American-type diet for 4 weeks. The primary outcomes are plasma concentration of C-reactive protein and concentration of ex-vivo interleukin-2 secreted upon stimulation of T cells with phytohemagglutinin.

Discussion

This will be the first controlled feeding study examining the contribution of obesity, hyperglycemia, and diet on systemic inflammation, immune cell phenotype, and function in adults of both sexes. Results of this clinical trial can ultimately be used to develop personalized dietary strategies to optimize immune function in individuals with obesity with different immune and metabolic profiles.

Clinical trial registration

ClinicalTrials.gov, identifier NCT04291391.

Ginger supplementation does not increase energy expenditure in female adults

Food components with thermogenic properties are promising antiobesity agents. Ginger (Zingiber officinale Rosc.) bioactive compounds have a capsaicin-like vanillyl portion, which has been attributed to thermogenic effect in previous experimental studies. However, studies conducted in humans have evaluated only the acute thermogenic effect of ginger, and demonstrated contradictory results. We evaluated the effect of long-term consumption of dry ginger extract on the resting energy expenditure (REE) of female adults with high body adiposity.

METHODS

This is a secondary analysis of a randomized, double-blind, placebo-controlled clinical trial (NCT02570633). Participants age 18 to 60 y were randomly assigned into two groups: Intervention (600 mg of ginger extract daily) and placebo (cellulose). The intervention lasted 3 mo. Anthropometric measurements, blood pressure, and REE were assessed at each visit.

RESULTS

A total of 66 female participants with high body adiposity were included in the analysis (mean age: 29 y [range, 20-55 y]; body mass index: 23.3 ± 2.7), with 30 participants in the ginger group and 36 in the placebo group. There were no significant differences in baseline characteristics between the groups. No differences were observed for group × time interaction on REE. Body composition and blood pressure followed the same pattern (all P > 0.05).

CONCLUSIONS

Ginger extract consumption for 3 mo did not change the REE, anthropometric, and clinical data of female adults with excess adiposity.

Sex Differences Distinctly Impact High-Fat Diet-Induced Immune Dysfunction in Wistar Rats

BACKGROUND

Immune function is altered during obesity. Moreover, males and females across different species demonstrate distinct susceptibility to several diseases. However, less is known regarding the interplay between high-fat diet (HFD) and sex in the context of immune function.

OBJECTIVES

The objective was to determine sex differences on immune function in response to an HFD compared with a control low-fat diet (LFD) in Wistar rats.

METHODS

At 5 wk of age, male and female Wistar rats were randomly assigned to 1 of 2 diets for 9 wk: ad libitum control LFD (20 kcal% fat, 53 kcal% carbohydrate, and 27 kcal% protein) or HFD (50 kcal% fat, 23 kcal% carbohydrate, and 27 kcal% protein). At 13 wk of age, rats were killed and splenocytes were isolated. Immune cell subsets were determined by flow cytometry. Immune cell function was determined by measuring the ex vivo cytokine production following stimulation with mitogens. Two-factor ANOVA was used to assess the main effect of sex, diet, and their interaction.

RESULTS

Males gained more weight than females (410 ± 46 vs. 219 ± 45 g), independently of diet (P-sex < 0.01). The HFD led to a lower production of IL-2 while increasing the production of IL-10 (both P-diet ≤ 0.05), independently of sex. HFD-fed females had increased production of cytokines (IL-2 and IL-6) after stimulation with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I), as well as a higher T-helper (Th) 1:Th2 balance compared with HFD-fed males (all P < 0.05). Males fed the HFD had significantly lower production of IL-2 upon stimulation compared with all other groups.

CONCLUSIONS

Female Wistar rats developed a milder obesity phenotype and maintained enhanced cytokine production compared with males fed the HFD. Sex differences modulate immune function in the context of high-fat feeding and it should be considered in research design to establish personalized health-related recommendations.

The Quality and Inflammatory Index of Diet in Patients With Migraine

Objectives

This study aims to verify if the quality of diet and the Dietary Inflammatory Index (DII) of migraine patients differ from that consumed by healthy individuals, and whether the severity of migraine is associated with these parameters.

Methods

This cross-sectional study was conducted at the Neurology Outpatient Clinic, Hospital das Clinicas, Universidade Federal de Minas Gerais – UFMG (Belo Horizonte, MG, Brazil). Patients with episodic migraine of both sexes, aged between 18–65 years were enrolled. Healthy volunteers without a history of primary headaches were recruited through advertisements and invitation to participate. Disability and impact caused by migraine were evaluated, respectively, by the Migraine Disability Test (MIDAS) and the Headache Impact Test, version 6 (HIT-6) questionnaires. Dietary intake was assessed using a 24-hour dietary recall and/or a three-day non-consecutive dietary record. The quality of diet was calculated using the Healthy Eating Index (HEI)-2015, adapted to the Brazilian population and DII was calculated based on the method developed by Shivappa et al. (2014).

Results

Ninety patients with migraine and 62 individuals without migraine were included in the study. The groups did not differ regarding age, sex, marital status, years of schooling and anthropometric characteristics. Patients with migraine had lower HEI total score than controls [50.9 (23.9 – 83.2) vs. 44.6 (27.1 – 67.7); P &lt; 0.01], indicating that these patients have poorer quality of diet. The scores of total fruits, whole fruits, total vegetables, added sugars, refined grains, and seafood and plant proteins were lower in the migraine group (P &lt; 0.05). In agreement with that, patients with migraine had higher DII than controls [1.0 (–1.80 – 3.17) vs. 1.7 (–1.52 – 3.67); P = 0.02] indicating that the intake of pro-inflammatory type foods and nutrients was higher in the migraine group. The HEI and DII scores did not correlate with migraine impact or severity (P &gt; 0.05).

Conclusions

 The quality and the inflammatory index of the diet may contribute to the physiopathology of migraine, but not necessarily to its severity.

Funding Sources

Brazilian government funding agencies (CNPq and CAPES) and UTHealth Houston Department of Psychiatry and Behavioral Sciences.

Sex Differences in Patients With Non-dialysis Dependent Chronic Kidney Disease on Serum Cytokines

Objectives

Cardiovascular (CV) mortality is higher in male compared to female patients with chronic kidney disease (CKD), but biological mechanisms for sex-specific differences are not established. Inflammation and high body fat are both associated with the development of CKD and CV diseases. Yet, little is known about the relationship between sex, body composition, and inflammation in CKD patients. The purpose of this study was to examine cytokines differences between male and female patients with CKD according to body composition.

Methods

This is a single center, cross-sectional study of patients with non-dialysis dependent CKD stages 3–5. Body composition was assessed by dual energy x-ray absorptiometry. Glomerular filtration rate (eGFR) was estimated by the CKD-EPI equation. Cytokines were measured using an ELISA multiplex assay kit for interleukin (IL) 4, IL6, IL8, IL10, IL12p70, IL17, monocyte chemoattractant protein-1, tumour necrosis factor alpha (TNFɑ), and interferon gamma (IFNγ). High fat mass and low appendicular muscle mass (ASM) was defined for females and males, respectively as ≥32%, ≥25%; and &lt;20 kg, &lt;15 kg.

Results

 Patients with CKD (n = 167; 53.3%males) aged 60.4 ± 11.3 years, eGFR 30.9 ± 30.2 mL/min, and BMI 26.7 ± 5.0 kg/m2 were included. Age, eGFR, and BMI were similar in both sexes. IL4 was higher in males compared to females (6.5 ± 1.0 vs 3.8 ± 0.9 pg/mL, P = 0.04). After stratifying according to body composition, IL4 remained higher (P = 0.04) in lean males compared to lean females, both with adequate ASM, but this difference disappeared in patients with high fat mass (male versus female). Within sex comparison, females with high fat mass have higher concentrations of IL4, IL8, and IL17 compared with lean females, whereas IL6, IL8, IL17, TNFɑ, and INFγ were higher in males with high fat mass.

Conclusions

Male and female patients with CKD present a different cytokine profile according to body composition. The higher levels of IL4 observed in males in the present study is consistent with recent evidence that IL4 exerts pro-inflammatory effects on vascular endothelium and is associated with an increase of CV events in CKD. Thus, IL4 might be a cytokine of interest to explain sex differences of CV events and mortality in CKD.

Funding Sources

Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro.

Expression of CD25 in Individuals With Obesity With or Without Insulin Resistance After Following a North American Diet

Objectives

Obesity and insulin resistance (IR) are associated with systemic inflammation, lower immune function, and a higher risk of infection. We previously reported that individuals with obesity and type 2 diabetes have an impaired T cell response (i.e., lower IL-2 production, a marker of proliferation) upon T cell stimulation despite having more activated T cells compared to normoglycemic (NG) individuals with obesity. It remains unclear if the immune dysfunction is caused by adiposity, hyperglycemia and/or dietary patterns. The aim of this study was to investigate the effect of consuming an isocaloric North American-type diet on the IL-2 receptor (CD25) expression and cardiometabolic risk factors in lean, obese-NG, and obese-IR individuals.

Methods

This is a three parallel-arm trial in controlled feeding conditions being conducted at the Human Nutrition Research Unit, at the University of Alberta. Three groups of adults: Lean-NG (n = 7), Obese-NG (n = 8), and Obese-IR (n = 9) consumed an isocaloric standardized diet containing 35% fat, 48% carbohydrate, and 17% protein for 4 weeks. All meals were provided to participants. Blood samples were collected in the fasting state before and after the intervention and cardiometabolic risk factors were measured. Peripheral blood mononuclear cells (PBMCs) were isolated and the proportion of total immune cells expressing CD25 was determined by flow cytometry.

Results

At baseline and post-intervention, Obese-IR had higher levels of glucose, insulin, and HOMA-IR and lower levels of HDL-C compared to both Lean-NG and Obese-NG groups (P &lt; 0.05). At baseline, the proportion of PBMCs expressing CD25 tended to be lower in the Lean-NG (17.6 ± 2.7) compared to both Obese-NG (23.3 ± 4.8) and Obese-IR (23.2 ± 4.8) (P = 0.08). Post-intervention, the expression of CD25 was reduced in Lean-NG and Obese-IR groups (P &lt; 0.01) but similar trends were still observed among all groups (P = 0.07).

Conclusions

Our preliminary data suggest that obesity, independent of IR, is associated with greater activation of immune cells and consuming a North American-type diet lowers the expression of the IL-2 receptor in individuals with and without obesity. Therefore, both excess adiposity and dietary pattern appear to modulate the function of immune cells in obesity.

Funding Sources

Canadian Institutes of Health Research.

Altered Serum Levels of Renin-Angiotensin System Markers in Migraine

OBJECTIVE

To compare the serum levels of renin-angiotensin system (RAS) components between patients with migraine and healthy controls, and to evaluate whether these levels are associated with migraine severity. We hypothesized that migraine would be associated with the activation of the inflammatory arm of the RAS, possibly leading to increased levels of angiotensin (Ang) II.

BACKGROUND

Recent studies have proposed the use of drugs that interfere with RAS, a hormonal system primarily implicated in blood pressure regulation, as a prophylactic strategy for migraine. However, no previous studies have directly assessed RAS components in migraine.

METHODS

This was a cross-sectional study involving 30 patients with episodic migraine who were in the interictal period and 20 healthy controls. This study was conducted at Hospital das Clínicas (Universidade Federal de Minas Gerais, Belo Horizonte, Brazil) outpatient clinic. Headache severity was evaluated using the Headache Impact Test, version 6 (HIT-6) and the Migraine Disability Test (MIDAS) questionnaires. Given that migraine is comorbid with mood disorders, depressive and anxious symptoms were evaluated using the Beck Anxiety and Depression Inventories (BDI and BAI), respectively. Clinical and demographic data were also collected. Serum levels of angiotensin-converting enzyme (ACE), ACE2, Ang II, and Ang (1-7) were measured by enzyme-linked immunosorbent assay.

RESULTS

Patients with migraine and controls were comparable in age, body mass index, blood pressure, and depressive and anxious symptoms. Patients with migraine showed lower levels of ACE [85.2 (66.8, 101.2) vs 65.5 (54.2, 77.5); P = .005] and lower ACE/ACE2 ratio [4.3 (3.4, 5.2) vs 3.5 (2.9, 4.1); P = .032] than controls. Conversely, patients with migraine had higher levels of Ang II [309.7 ± 147.4 vs 605.4 ± 200.4; difference: -287.1 (95% CI: -391.4--182.8), P < .001] and Ang (1-7) [214.4 ± 155.8 vs 397.9 ± 217.9; difference: -184.6 (95% CI: -296.7--72.6), P = .001] than controls. There were no correlations between RAS serum markers and migraine severity scores (HIT and MIDAS) or depressive and anxious symptoms (BDI and BAI) (P > .05).

CONCLUSIONS

Altogether, our results suggest the participation of RAS in migraine pathophysiology, but not in its severity.

Accuracy of the MedGem® portable indirect calorimeter for measuring resting energy expenditure in adults with class II or III obesity

BACKGROUND AND AIMS

The accuracy of some portable indirect calorimeters in estimating resting energy expenditure (REE) - and hence energy recommendations - among pre-bariatric patients is unknown. Our objective was to assess the accuracy of the MedGem® among individuals with class II or III obesity awaiting bariatric surgery.

METHODS

Male and female adults who were awaiting bariatric surgery were recruited to this cross-sectional study. MedGem-derived oxygen consumption (O₂) and REE were compared to O₂ and REE from a metabolic cart. REE was also calculated using several common equations to assess the clinical utility of this portable tool. Body composition was assessed by dual energy X-Ray absorptiometry. Paired t-test and Bland-Altman analysis (expressed as bias [average difference] and limits of agreement [bias ± 2 standard deviations]) evaluated O₂ and REE accuracy.

RESULTS

Twenty-six individuals were included (34 ± 9 years old; n = 20, 76.9% female), with the majority (n = 15, 57.7%) having class II obesity. Neither O₂ (MedGem: 283 ± 63 vs. metabolic cart: 293 ± 64 ml/min, p = 0.114) nor REE (MedGem: 1963 ± 437 vs. metabolic cart: 2047 ± 440 kcal/day, p = 0.057) were different between devices. Body composition did not relate to bias. The MedGem had wide limits of agreement for REE (-504 to 336 kcal/day), which was similar to predictive equations.

CONCLUSIONS

Although REE from the MedGem was not different than REE from the metabolic cart, individual-level accuracy was poor and similar to predictive equations in patients with class II or III obesity. Nonetheless, efficacy of repeated assessments during weight loss warrant future investigation.

Double-blind placebo-controlled randomized clinical trial of ginger (Zingiber officinale Rosc.) in the prophylactic treatment of migraine

BACKGROUND

Previous studies have shown an analgesic effect of ginger in the acute treatment of migraine, and there is anecdotal evidence of its efficacy in migraine prophylaxis.

OBJECTIVE

This study aimed to evaluate the potential of ginger to prevent migraine attacks.

METHODS

This double-blind, placebo-controlled randomized clinical trial took place at the Headache Clinic, Universidade Federal de Minas Gerais (Belo Horizonte, Minas Gerais, Brazil), involving 107 patients. Only subjects diagnosed with episodic migraine, aged between 18 and 60 years old, and who were not taking any prophylactic medication, were enrolled in the study. After one month of observation, subjects selected for the study were randomized 1:1 into placebo and treatment groups. Patients received capsules three times per day of 200 mg of dry extract of ginger (5% active ingredient) or placebo (cellulose) for three months. Visits were performed monthly and the patients were asked to fill in a migraine diary. The adherence to treatment was evaluated by counting capsules.

RESULTS

The percentage of patients who responded to treatment (i.e. a reduction of 50% in the number of migraine attacks at the end of treatment) did not differ between the groups. There was a decrease in the number of days with severe pain, analgesic use for acute migraine and duration of migraine attacks in both groups, without significant difference between ginger and placebo groups.

CONCLUSIONS

Ginger provides no greater benefit in the prophylactic treatment of migraine when compared to placebo. This trial is registered at ClinicalTrials.gov (NCT02570633).