Morbidly obese human subjects have increased peripheral blood CD4+ T cells with skewing toward a Treg- and Th2-dominated phenotype

Does excess body weight accelerate immune aging?

BACKGROUND

Overweight and obesity in older adults increase the risk of a range of comorbidities by sustaining chronic inflammation and thus enhancing immunosenescence. This study aimed to assess whether excess body mass affected disproportion in T lymphocytes. Therefore, the study was designed to explain whether excess body mass in older individuals affected the disproportion in numbers of T lymphocytes and whether anthropometric indices and immune risk profile expressed as CD4/CD8 ratio are diagnostically useful in the analysis of immunosenescence.

MATERIALS & METHODS

One hundred three individuals aged 73.6 ± 3.1 years were allocated to the normal body mass (body mass index (BMI) 18.5-24.9 kg/m2,n = 39), the pre-obesity (BMI 25.0-29.9 kg/m2, n = 44) or the obesity (BMI ≥30.0 kg/m2, n = 20) group, based on WHO recommendations. Details on the subjects' medical history and lifestyle were obtained by health questionnaire. Anthropometric analysis was performed by bioelectrical impedance method, biochemical analysis was made by the automatic analyzer and ELISA immunoassays, and T and B lymphocyte counts were determined by eight-parameter flow cytometry. Additionally, visceral adiposity index, body adiposity index (BAI), and body shape index (ABSI) were evaluated based on body circumference, BMI and lipid-lipoprotein profile measurements.

RESULTS

The highest percentage of CD3+CD4+ T lymphocytes (59.4 ± 12.6 %) and the lowest CD3+CD8+ T lymphocytes (31.6 ± 10.0 %) were noted in patients the obesity group. The highest cut-off value of 1.9 for CD4/CD8 ratio was recorded in the normal body mass vs pre-obesity model. CD4/CD8 ratio > 2.5 was recorded in >20 % of our pre-obesity and obesity groups while 64.5 % of the normal body mass group had CD4/CD8 ratio < 1. High diagnostic usefulness was demonstrated for both BAI and lipid accumulation product (LAP) (AUC values of ~0.800 and ~ 0.900 respectively) in three models: normal body mass vs pre-obesity, normal body mass vs obesity, and pre-obesity vs obesity.

CONCLUSION

The odds ratios (OR) for CD4/CD8 ratio in the normal body mass vs obesity model (OR = 16.1, 95%CI 3.8-93.6) indicated a potential diagnostic value of T lymphocytes for clinical prognosis of immune aging in relation to excess body weight in older adults. High values of AUC obtained for the following models: CD4/CD8 + BAI (AUC = 0.927), CD4/CD8 + LAP (AUC = 1.00), CD4/CD8 + ABSI (AUC = 0.865) proved to provide excellent discrimination between older adults with obesity and with normal body mass.

Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.

Impact of body mass index on peripheral and uterine immune status in the window of implantation in patients with recurrent reproductive failure

This study aimed to investigate whether maternal obesity affects the immune status of peripheral blood and endometrium in patients with recurrent reproductive failure classified according to their body mass index (BMI). A total of 228 repeated implantation failure (RIF) and 266 recurrent miscarriage (RM) patients were enrolled in the study and further subdivided into three groups according to their BMI: (i) normal weight (18.5≤ BMI <23); (ii) overweight (23≤ BMI <25); and (iii) obese (BMI ≥25). Peripheral blood and endometrium samples were collected in the mid-luteal phase before IVF treatment or natural pregnancy. Peripheral immunocytes were analyzed by flow cytometry, while uterine immune cells were subjected to immunohistochemistry. In RM patients, significantly increased peripheral helper T cells and decreased cytotoxic T cells, NK cells were observed in the obese group compared with the normal-weight group. Meanwhile, in the endometrium, the percentage of NK cell, macrophage cell, M2 macrophage cell, and Treg cell significantly reduced with increased BMI in RIF patients, and the percentage of NK cell and M2 macrophage cell significantly decreased with increased BMI in RM patients. In conclusion, obesity may cause endometrial immune disorder in recurrent reproductive failure women, but was only associated with the peripheral immune change in RM patients.

Supplementation with EPA and DHA omega-3 fatty acids improves peripheral immune cell mitochondrial dysfunction and inflammation in subjects with obesity

Omega-3 fatty acids (w-3 FA) have anti-inflammatory effects and improve mitochondrial function. Nonetheless, little is known about their effect on mitochondrial bioenergetics of peripheral blood mononuclear cells (PBMCs) in individuals with obesity. Thus, this study aimed to determine the mitochondrial bioenergetics status and cell subset composition of PBMCs during obesity, before and after 1 month supplementation with w-3 FA. We performed a case-control study with twelve women with normal BMI (lean group) and 19 with grade 2 obesity (obese group), followed by a before-after prospective study where twelve subjects with obesity received a 1 month intervention with 5.25 g of w-3 FA (3.5 g eicosapentaenoic (EPA) and 1.75 g docosahexaenoic (DHA) acids), and obtained PBMCs from all participants. Mitochondrial bioenergetic markers, including basal and ATP-production associated respiration, proton leak, and nonmitochondrial respiration, were higher in PBMCs from the obese group vs. the lean group. The bioenergetic health index (BHI), a marker of mitochondrial function, was lower in the obese vs. the lean group. In addition, Th1, Th2, Th17, CD4+ Tregs, CD8+ Tregs, and Bregs, M1 monocytes and pDCreg cells were higher in PBMCs from the obese group vs. the lean group. The w-3 FA intervention improved mitochondrial function, mainly by decreasing nonmitochondrial respiration and increasing the reserve respiratory capacity and BHI. The intervention also reduced circulating pro-inflammatory and anti-inflammatory lymphocyte and monocytes subsets in individuals with obesity. The mitochondrial dysfunction of PBMCs and the higher proportion of peripheral pro-inflammatory and anti-inflammatory immune cells in subjects with obesity, improved with 1 month supplementation with EPA and DHA.

Western-style diet in the presence of elevated circulating testosterone induces adipocyte hypertrophy without proinflammatory responses in rhesus macaques

PROBLEM

Anovulatory infertility is commonly associated with hyperandrogenemia (elevated testosterone, T), insulin resistance, obesity, and white adipose tissue (WAT) dysfunction associated with adipocyte hypertrophy. However, whether hyperandrogenemia and adipocyte hypertrophy per se induce a proinflammatory response is unknown.

METHOD OF STUDY

Young adult female rhesus macaques were exposed to an obesogenic Western-style diet (WSD) in the presence of elevated circulating testosterone (T+WSD) or a low-fat control diet with no exogenous T. Immune cells residing in visceral omental white adipose tissue (OM-WAT), corpus luteum and the contralateral ovary, endometrium, lymph nodes, bone marrow, and peripheral blood mononuclear cells were characterized by flow cytometry during the luteal phase of the reproductive cycle.

RESULTS

Following one year of treatment, T+WSD animals became more insulin-resistant and exhibited increased body fat and adipocyte hypertrophy compared to controls. T+WSD treatment did not induce macrophage polarization toward a proinflammatory phenotype in the tissues examined. Additionally, T+WSD treatment did not affect TNFα production by bone marrow macrophages in response to toll-like receptor agonists. While the major lymphoid subsets were not significantly affected by T+WSD treatment, we observed a significant reduction in the frequency of effector memory CD8+ T-cells (Tem) in OM-WAT, but not in other tissues. Notably, OM-WAT Tem frequencies were negatively correlated with insulin resistance as assessed by the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).

CONCLUSION

This study shows that short-term T+WSD treatment induces weight gain, insulin resistance, and adipocyte hypertrophy, but does not have a significant effect on systemic and tissue-resident proinflammatory markers, suggesting that adipocyte hypertrophy and mild hyperandrogenemia alone are not sufficient to induce a proinflammatory response.

Associations between anthropometric parameters and immune-phenotypical characteristics of circulating Tregs and serum cytokines

OBJECTIVE

To investigate the associations between several anthropometric parameters and regulatory T cells (Tregs) and circulating cytokines in a population-based cohort.

METHODS

Between 2018 and 2021, a total of 238 participants were examined up to three times within the scope of the MEGA study in Augsburg, Germany. Tregs were analyzed using flow cytometry and the serum concentrations of 52 cytokines were determined. Anthropometric parameters were measured, using also bioelectrical impedance analysis: body mass index (BMI), relative total body fat, relative visceral adipose tissue (rVAT), waist circumference (WC), waist-to-hip ratio (WHR) and body fat distribution. Associations were analyzed using linear mixed models with random intercept (Tregs) and conventional linear regression models (cytokines).

RESULTS

WC and WHR were inversely associated with the general Treg subset. Four parameters (BMI, rVAT, WC, and WHR) were inversely associated with the conventional Treg population. Three cytokines showed a particularly strong association with several anthropometric parameters: the cutaneous T-cell attracting chemokine was inversely associated with anthropometric parameters, while hepatocyte growth factor and interleukine-18 showed positive associations.

CONCLUSIONS

Anthropometric measures are associated with Tregs and serum cytokine concentrations revealing new important interconnections between obesity and the adaptive immune system.

Immune cell status, cardiorespiratory fitness and body composition among breast cancer survivors and healthy women: a cross sectional study

Methods: We examined whether immune cell profiles differ between healthy women (n = 38) and breast cancer survivors (n = 27) within 2 years of treatment, and whether any group-differences were influenced by age, cytomegalovirus infection, cardiorespiratory fitness and body composition. Using flow cytometry, CD4+ and CD8+ T cell subsets, including naïve (NA), central memory (CM) and effector cells (EM and EMRA) were identified using CD27/CD45RA. Activation was measured by HLA-DR expression. Stem cell-like memory T cells (TSCMs) were identified using CD95/CD127. B cells, including plasmablasts, memory, immature and naïve cells were identified using CD19/CD27/CD38/CD10. Effector and regulatory Natural Killer cells were identified using CD56/CD16. Results: Compared to healthy women, CD4+ CM were +Δ21% higher among survivors (p = 0.028) and CD8+ NA were -Δ25% lower (p = 0.034). Across CD4+ and CD8+ subsets, the proportion of activated (HLA-DR+) cells was +Δ31% higher among survivors: CD4+ CM (+Δ25%), CD4+ EM (+Δ32%) and CD4+ EMRA (+Δ43%), total CD8⁺ (+Δ30%), CD8+ EM (+Δ30%) and CD8+ EMRA (+Δ25%) (p < 0.046). The counts of immature B cells, NK cells and CD16+ NK effector cells were higher among survivors (+Δ100%, +Δ108% and +Δ143% respectively, p < 0.04). Subsequent analyses examined whether statistically significant differences in participant characteristics, influenced immunological differences between groups. Compared to healthy women, survivors were older (56 ± 6 y vs. 45 ± 11 y), had lower cardiorespiratory fitness (V˙O2max mL kg^-1 min^-1: 28.8 ± 5.0 vs. 36.2 ± 8.5), lower lean mass (42.3 ± 5.0 kg vs. 48.4 ± 15.8 kg), higher body fat (36.3% ± 5.3% vs. 32.7% ± 6.4%) and higher fat mass index (FMI kg/m²: 9.5 ± 2.2 vs. 8.1 ± 2.7) (all p < 0.033). Analysis of covariance revealed divergent moderating effects of age, CMV serostatus, cardiorespiratory fitness and body composition on the differences in immune cell profiles between groups, depending on the cell type examined. Moreover, across all participants, fat mass index was positively associated with the proportion of HLA-DR+ CD4+ EMRA and CD8+ EM/EMRA T cells (Pearson correlation: r > 0.305, p < 0.019). The association between fat mass index and HLA-DR+ CD8+ EMRA T cells withstood statistical adjustment for all variables, including age, CMV serostatus, lean mass and cardiorespiratory fitness, potentially implicating these cells as contributors to inflammatory/immune-dysfunction in overweight/obesity.

Differential effects of high dose omega-3 fatty acids on metabolism and inflammation in patients with obesity: eicosapentaenoic and docosahexaenoic acid supplementation

Background

Obesity is complicated by low-grade chronic inflammation characterised by increases in inflammatory proteins and cells in peripheral blood. It has been known that omega-3 fatty acids (FA) like eicosapentaenoic (EPA) and docosahexaenoic (DHA) could modulate the inflammatory process and improve metabolic markers.

Objective

This study aimed to determine the effect of high-dose omega-3 FA on metabolic and inflammatory markers among patients with obesity and healthy volunteers.

Methods

This prospective study included 12 women with obesity (body mass index [BMI] ≥ 35.0 kg/m²) and 12 healthy women (BMI < 24.0 kg/m²) who were supplemented with a dose of 4.8 g/day (3.2 g EPA plus 1.6 g DHA) for 3 months followed by no treatment for 1 month. Plasma metabolic and inflammatory markers and levels of mRNA transcripts of CD4⁺ T lymphocyte subsets were determined monthly.

Results

None of the participants exhibited changes in weight or body composition after study completion. EPA and DHA supplementation improved metabolic (insulin, Homeostatic Model Assessment of Insulin Resistance [HOMA-IR], triglyceride [TG]/ high-density lipoprotein [HDL] ratio, TG, and arachidonic acid [AA]/EPA ratio) and tumor necrosis factor-alpha (TNF-α). Moreover, the levels of mRNA transcripts of T CD4⁺ lymphocyte subsets (TBX21, IFNG, GATA-3, interleukin [IL]-4, FOXP3, IL-10 IL-6, and TNF-α), were down-regulated during the intervention phase. After 1 month without supplementation, only insulin, HOMA-IR and the mRNA transcripts remained low, whereas all other markers returned to their levels before supplementation.

Conclusion

Supplementation with high-dose omega-3 FAs could modulate metabolism and inflammation in patients with obesity without weight loss or changes in body composition. However, these modulatory effects were ephemeral and with clear differential effects: short-duration on metabolism and long-lasting on inflammation.

Characterization of lymphocyte profiles in children with syndromic obesity

BACKGROUND

Little is known about blood lymphocyte subpopulations in children with common (CO) or syndromic (SO) obesity. We aimed to describe the blood lymphocyte profiles of obese children and to search for associations with clinical phenotypes.

METHODS

Main blood lymphocyte subpopulations were analyzed in 159 children with CO and 34 with SO in a retrospective cohort. Phenotypes included obesity history, body mass index (BMI) Z score, percentage fat mass, and inflammatory parameters. Correlations were performed between phenotypes and circulating lymphocyte profiles.

RESULTS

Children with SO had a higher BMI Z score (5.5 ± 1.7 SD) than children with CO (4.7 ± 0.9 SD; p = 0.01). Significant differences were found for lymphocyte counts, including a higher percentage of CD19⁺ B cells (SO = 20.1 ± 6.7 vs. CO = 17.1 ± 6.1%, p = 0.03), despite lower absolute numbers (SO = 0.57 ± 0.20 vs. CO = 0.63 ± 1.9 g/L, p < 0.01). However, no difference in the lymphocyte profile was found between children with SO and those with the most severe CO (BMI Z score ≥ 4.7 SD).

CONCLUSION

Children with SO have altered blood lymphocyte profiles with increased prevalence of CD19⁺ B cells, which is closely linked to the degree of obesity severity and inflammatory markers.

In obese hypertensives cholecalciferol inhibits circulating TH17 cells but not macrophage infiltration on adipose tissue

In arterial hypertension, increased Th17 cells and reduced Tregs are the hallmarks of immunological dysfunction and the basis for the investigation of immunomodulatory drugs. Although cholecalciferol is not a primary immunomodulator, it has recognized action on immune cells, leading us to hypothesise if cholecalciferol can induce a more tolerogenic phenotype in obese hypertensives. In a phase-2, single-centre, randomised, open, 24-week trial, we assigned adults with obesity-associated hypertension and vitamin D deficiency to receive usual therapy plus 50,000 IU/week of cholecalciferol or usual therapy alone. The primary endpoint was the percentual variation in T CD4⁺, T CD8⁺, Tregs, and Th17 cells. Secondary endpoints included the percentual variation in Th1, Tc1, Tc17, and monocytes and variation in the number of perivascular and non-perivascular macrophages, T CD4⁺ and T CD8⁺ lymphocytes in subcutaneous abdominal adipose tissue. A control group of 12 overweight normotensives was also evaluated for peripheral immune cells. A total of 36 obese hypertensives were randomised, 18 in each group. In comparison with normotensive controls, hypertensives presented higher percentages of T lymphocytes (p = 0.016), Tregs (p = 0.014), and non-classical monocytes (p < 0.001). At week 24, Th17 cells increased in control group (p = 0.017) but remained stable in cholecalciferol group. For Tregs, downregulation towards the values of normotensive controls was observed (p = 0.003), and in multivariate analysis, an increased loading in the setting of the cells of adaptive immunity observed (eigenvalue 1.78, p < 0.001). No changes were documented for monocytes. In adipose tissue, a baseline negative correlation between vitamin D and perivascular macrophages was observed (r = -0.387, p = 0.024) that persisted in the control group (r = -0.528, p = 0.024) but not in the cholecalciferol group, which presented an increase in non-perivascular macrophages (p = 0.029) at week 24. No serious adverse events were reported for all the participants. In this trial, we found that supplementation with cholecalciferol interfered with peripheral and adipose tissue immune cell profile, downregulating peripheral Th17 cells, but increasing the number of infiltrating subcutaneous adipose tissue macrophages. (Funded by Núcleo Estudos Hipertensão da Beira Interior; EudraCT number: 2015-003910-26).

Drastic transformation of visceral adipose tissue and peripheral CD4 T cells in obesity

Obesity has a pronounced effect on the immune response in systemic organs that results in not only insulin resistance but also altered immune responses to infectious diseases and malignant tumors. Obesity-associated microenvironmental changes alter transcriptional expression and metabolism in T cells, leading to alterations in T-cell differentiation, proliferation, function, and survival. Adipokines, cytokines, and lipids derived from obese visceral adipose tissue (VAT) may also contribute to the systemic T-cell phenotype, resulting in obesity-specific pathogenesis. VAT T cells, which have multiple roles in regulating homeostasis and energy utilization and defending against pathogens, are most susceptible to obesity. In particular, many studies have shown that CD4 T cells are deeply involved in the homeostasis of VAT endocrine and metabolic functions and in obesity-related chronic inflammation. In obesity, macrophages and adipocytes in VAT function as antigen-presenting cells and contribute to the obesity-specific CD4 T-cell response by inducing CD4 T-cell proliferation and differentiation into inflammatory effectors via interactions between major histocompatibility complex class II and T-cell receptors. When obesity persists, prolonged stimulation by leptin and circulating free fatty acids, repetitive antigen stimulation, activating stress responses, and hypoxia induce exhaustion of CD4 T cells in VAT. T-cell exhaustion is characterized by restricted effector function, persistent expression of inhibitory receptors, and a transcriptional state distinct from functional effector and memory T cells. Moreover, obesity causes thymic regression, which may result in homeostatic proliferation of obesity-specific T-cell subsets due to changes in T-cell metabolism and gene expression in VAT. In addition to causing T-cell exhaustion, obesity also accelerates cellular senescence of CD4 T cells. Senescent CD4 T cells secrete osteopontin, which causes further VAT inflammation. The obesity-associated transformation of CD4 T cells remains a negative legacy even after weight loss, causing treatment resistance of obesity-related conditions. This review discusses the marked transformation of CD4 T cells in VAT and systemic organs as a consequence of obesity-related microenvironmental changes.

The Impact of LEP rs7799039 Polymorphism and Obesity on the Severity of Coronavirus Disease-19

BACKGROUND AND AIMS

SARS-CoV-2 infection has been recorded in 230 countries to date. Obesity has a negative impact on one's quality of life and is one of the main causes of mortality globally. Obesity affects the immune system, making the host more susceptible to infectious infections. Also, obesity commonly provokes the severity of respiratory diseases so the correlation of LEP rs7799039 Polymorphism in corpulent patients with COVID-19 infection was clearly investigated in the current study.

METHODS

A total of 232 patients were recruited, 116 patients were obese with COVID-19 infection, and 116 patients were non obese COVID-19. Fasting blood glucose test (FBG), hemoglobin A1C (HbA1C), complete blood count (CBC), international normalized ratio (INR), urea, alanine transaminase (ALT), aspartate aminotransferase (AST), D dimer and C-reactive protein (CRP) were estimated. C.T. scan was performed for each patient, and C.T. severity score was calculated. Genotyping for the leptin rs7799039 SNPs was performed by TaqMan^® (Applied Biosystems Step One ^TM Real-time PCR).

RESULTS

Regarding LEP polymorphism, all individuals of non-obese groups significantly had the homozygous allele GG (100%), whereas only 56% of obese groups had GG alleles (P = 0.001). The severity scores significantly (P = 0.001) varied regarding LEP polymorphism regarding Rs7799039, where the largest proportion of those with Grade IV had the homozygous allele AA (57.1%).

CONCLUSION

There was a correlation between the leptin gene allelic discrimination and COVID-19 CT brutality in obese patients. The A allele was considered a risk factor for severity in COVID-19 patients while the G allele contributes to decreasing that risk.

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.

Inflammation and Metabolism of Influenza-Stimulated Peripheral Blood Mononuclear Cells From Adults With Obesity Following Bariatric Surgery

BACKGROUND

Obesity dysregulates immunity to influenza infection. Therefore, there is a critical need to investigate how obesity impairs immunity and to establish therapeutic approaches that mitigate the impact of increased adiposity. One mechanism by which obesity may alter immune responses is through changes in cellular metabolism.

METHODS

We studied inflammation and cellular metabolism of peripheral blood mononuclear cells (PBMCs) isolated from individuals with obesity relative to lean controls. We also investigated if impairments to PBMC metabolism were reversible upon short-term weight loss following bariatric surgery.

RESULTS

Obesity was associated with systemic inflammation and poor inflammation resolution. Unstimulated PBMCs from participants with obesity had lower oxidative metabolism and adenosine triphosphate (ATP) production compared to PBMCs from lean controls. PBMC secretome analyses showed that ex vivo stimulation with A/Cal/7/2009 H1N1 influenza led to a notable increase in IL-6 with obesity. Short-term weight loss via bariatric surgery improved biomarkers of systemic metabolism but did not improve markers of inflammation resolution, PBMC metabolism, or the PBMC secretome.

CONCLUSIONS

These results show that obesity drives a signature of impaired PBMC metabolism, which may be due to persistent inflammation. PBMC metabolism was not reversed after short-term weight loss despite improvements in measures of systemic metabolism.

T and B Cell Composition and Cytokine Producing Capacity Before and After Bariatric Surgery

Morbid obesity is associated with a chronic state of low-grade inflammation, which may lead to accelerated differentiation of T and B cells. These differentiated immune cells are strongly cytotoxic and have an increased pro-inflammatory cytokine producing capacity. Furthermore, the anti-inflammatory function of the T and B cells decreases. The aim of this study was to evaluate the effect of morbid obesity on the subset profile and cytokine producing capacity of T and B cells. Subsequently, we assessed whether bariatric surgery affected the subset profile and cytokine producing capacity of these cells. We determined the proportion of T and B cell subsets and their cytokine producing capacity in peripheral blood collected from 23 morbidly obese patients before and three months after bariatric surgery using flow-cytometry. We compared this with the results of 25 lean controls. Both CD4+ and CD8+ T cells showed a more differentiated subset profile in morbidly obese patients as compared to lean controls, which was not recovered three months after bariatric surgery. The B cell composition of morbidly obese patients after bariatric surgery adjusted towards the profile of lean controls. However, the IL-2 and IFN-γ producing capacity of CD8+ T cells and the IL-2, IFN-γ, TNF-α and IL-10 producing capacity of B cells was not restored three months after bariatric surgery. In conclusion, the data suggest that the immune system has the capacity to recover from the detrimental effects of morbid obesity within three months after bariatric surgery in terms of cell composition; however, this was not seen in terms of cytokine producing capacity. The full restoration of the immune system after bariatric surgery may thus take longer.

Obesity: A comorbidity-acquired immunodeficiency syndrome (CAIDS)

Accumulating data emphasize a strong link between obesity and the severity of coronavirus disease-2019 (COVID-19), including mortality. Obesity interferes with several components of the immune system including lymphoid tissue's integrity, leukocytes' development and function, complement system's activation, and the coordination of innate and adaptive immune responses. Overall, obesity results in a less efficient immune response to infectious agents. Severe acute respiratory syndrome coronavirus 2 exploits this weakened immune system in people with obesity to precipitate COVID-19, and in some cases death. It is therefore the author's recommendation that obesity should be viewed as another form of acquired immunodeficiency syndrome and be treated with the appropriate seriousness. Unlike the previously described acquired immunodeficiency syndrome (AIDS) that is caused by the Human Immunodeficiency Virus (HIV), obesity is a comorbidity-acquired immunodeficiency syndrome. People with AIDS do not die from HIV, but may die from opportunistic pathogens such as Mycobacterium tuberculosis. However, AIDS is ascribed its due importance in the course of deterioration of the patient. Similarly, obesity should be acknowledged further as a risk factor for mortality from COVID-19. Obesity is a modifiable condition and even in people with a strong genetic predisposition, lifestyle modifications can reverse obesity, and even moderate weight loss can improve the inflammatory milieu. Strong public health actions are warranted to promote lifestyle measures to reduce the burden from overweight and obesity that currently affect more than one-third of the global population, with projections alarming this may reach 55-80% within the next thirty years.

Clostridium butyricum Inhibits Fat Deposition via Increasing the Frequency of Adipose Tissue-Resident Regulatory T Cells

SCOPE

Clostridium butyricum (CB) exerts beneficial actions in several disorders. However, the impact and molecular cues of CB in fat metabolism remain elusive. This study demonstrates the CB inhibition of fat deposition by increasing the relative number of adipose tissue-resident Treg cells (aTregs).

METHODS AND RESULTS

CB is administered orally to wild type (WT) mice fed with chow diet, which decrease fat deposition and adipogenic gene expression, associating with elevated serum levels of butyrate. Sodium butyrate (SB) feeding mimics the CB suppression of fat accumulation. Of note, the frequency of aTregs in both the CB and SB treatments, analyzed by flow cytometry, is markedly increased, accompanied by activated Wnt10b expression in white adipose tissues. However, CB and SB fail to inhibit fat deposition in Wnt10b-KO mice. Intriguingly, CB and SB are able to alleviate the obesity, fatty liver, and glucose abnormalities in high fat diet (HFD)-fed WT mice.

CONCLUSIONS

These findings suggest that CB, through its metabolite butyrate, inhibits fat deposition via potentiating aTreg cell generation, and support the option of CB and SB for therapeutic interventions in obesity and related disorders.

Influence of adipose tissue immune dysfunction on childhood obesity

In recent decades, a dramatic rise has been observed in the prevalence of obesity in childhood and adolescence, along with an increase in fetal microsomia rates. The increased risk of obesity during this key period in development negatively affects the health of the individual later in life. Immune cells residing and recruited to white adipose tissue have been highlighted as important factors contributing to the pathogenesis of childhood obesity. Immune dysfunction in the context of obesity begins early in childhood, which is different from the pathological characteristics and influencing factors of adipose immunity in adults. Here, we explore the current understanding of the roles of childhood and early life events that result in high risks for obesity by influencing adipose tissue immune dysfunction under the pathological condition of obesity. Such knowledge will help in determining the mechanisms of childhood and early life obesity in efforts to ameliorate chronic inflammation-related metabolic diseases.

Leptin Promotes Greater Ki67 Expression in CD4+ T Cells From Obese Compared to Lean Persons Living With HIV

While antiretroviral therapy (ART) has proven effective in suppressing viremia and disease progression among people living with human immunodeficiency virus (HIV; PLWH), suboptimal CD4⁺ T cell reconstitution remains a major obstacle in nearly 30% of ART-treated individuals. Epidemiological studies demonstrate that obesity, or a body mass index (BMI) ≥ 30 kg/m², is positively correlated with greater CD4⁺ T cell recovery in PLWH on ART. Leptin is a known immunomodulator that is produced in proportion to fat mass and is increased in obese individuals, including PLWH. We hypothesized that CD4⁺ T cells from obese PLWH have increased cell proliferation and cytokine production compared to cells from lean PLWH, potentially modulated by differential effects of leptin signaling. To test this hypothesis, peripheral blood mononuclear cells from obese and lean PLWH with long-term virologic suppression on the same ART regimen were pretreated with recombinant leptin and then stimulated with anti-CD3/CD28 or PMA/ionomycin to measure Ki67 expression, leptin receptor (LepR) surface expression and cytokine production. In the absence of leptin, Ki67 expression and IL-17A production were significantly higher in CD4⁺ T cells from obese compared to lean PLWH. However, LepR expression was significantly lower on CD4⁺ T cells from obese compared to lean PLWH. After leptin treatment, Ki67 expression was significantly increased in CD4⁺ T cells from obese PLWH compared to the lean participants. Leptin also increased IL-17A production in CD4⁺ T cells from obese healthy controls. In contrast, leptin decreased IL-17A production in CD4⁺ T cells from both obese and lean PLWH. Combined, these results demonstrate that obesity is associated with greater CD4⁺ T cell proliferation among PLWH, and that higher circulating leptin levels in obesity may contribute to improved CD4⁺ T reconstitution in PLWH initiating ART.

Laparoscopic sleeve gastrectomy for morbid obesity improves gut microbiota balance, increases colonic mucosal-associated invariant T cells and decreases circulating regulatory T cells

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) for morbid obesity may improve gut microbiota balance and decrease chronic inflammation. This study examines the changes in gut microbiota and immune environment, including mucosal-associated invariant T cells (MAIT cells) and regulatory T cells (Treg cells) caused by LSG.

METHODS

Ten morbidly obese patients underwent LSG at our institution between December 2018 and March 2020. Flow cytometry for Th1/Th2/Th17 cells, Treg cells and MAIT cells in peripheral blood and colonic mucosa and 16S rRNA analysis of gut microbiota were performed preoperatively and then 12 months postoperatively.

RESULTS

Twelve months after LSG, the median percent total weight loss was 30.3% and the median percent excess weight loss was 66.9%. According to laboratory data, adiponectin increased, leptin decreased, and chronic inflammation improved after LSG. In the gut microbiota, Bacteroidetes and Fusobacteria increased after LSG, and indices of alpha diversity increased after LSG. In colonic mucosa, the frequency of MAIT cells increased after LSG. In peripheral blood, the frequency of Th1 cells and effector Treg cells decreased after LSG.

CONCLUSIONS

After LSG for morbid obesity, improvement in chronic inflammation in obesity is suggested by change in the constituent bacterial species, increase in the diversity of gut microbiota, increase in MAIT cells in the colonic mucosa, and decrease in effector Treg cells in the peripheral blood.

The Interplay of Obesity, Dyslipidemia and Immune Dysfunction: A Brief Overview on Pathophysiology, Animal Models, and Nutritional Modulation

Obesity has emerged as a leading global health concern. It is characterized by chronic low-grade inflammation, which impairs insulin signaling, lipid metabolism and immune function. Recent findings from animal and clinical studies have begun to elucidate the underlying mechanisms of immune dysfunction seen in the context of obesity. Here, we provide a brief review on the current understanding of the interplay between obesity, dyslipidemia and immunity. We also emphasize the advantages and shortcomings of numerous applicable research models including rodents and large animal swine that aim at unraveling the molecular basis of disease and clinical manifestations. Although there is no perfect model to answer all questions at once, they are often used to complement each other. Finally, we highlight some emerging nutritional strategies to improve immune function in the context of obesity with a particular focus on choline and foods that contains high amounts of choline.

Pandemics of the 21st Century: The Risk Factor for Obese People

The number of obese adults and children is increasing worldwide, with obesity now being a global epidemic. Around 2.8 million people die annually from clinical overweight or obesity. Obesity is associated with numerous comorbid conditions including hypertension, cardiovascular disease, type 2 diabetes, hypercholesterolemia, hypertriglyceridemia, nonalcoholic fatty liver disease, and cancer, and even the development of severe disease after infection with viruses. Over the past twenty years, a number of new viruses has emerged and entered the human population. Moreover, influenza (H1N1)pdm09 virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have caused pandemics. During pandemics, the number of obese patients presents challenging and complex issues in medical and surgical intensive care units. Morbidity amongst obese individuals is directly proportional to body mass index. In this review, we describe the impact of obesity on the immune system, adult mortality, and immune response after infection with pandemic influenza virus and SARS-CoV-2. Finally, we address the effect of obesity on vaccination.

Th1/Th2 Balance in Young Subjects: Relationship with Cytokine Levels and Metabolic Profile

Purpose

We aim to identify Th1 and Th2 cell clusters in young subjects, including their clinical and metabolic characteristics and the Th1/Th2 balance.

Patients and Methods

A total of 100 participants were included. The frequencies of Th1 and Th2 cells in peripheral blood were determined by flow cytometry. Serum C-reactive protein was measured using a turbidimetric assay, and insulin levels were quantified with an enzyme-linked immunosorbent assay. Circulating cytokine levels were analyzed using a multiplex system.

Results

A cluster analysis was performed to determine the Th1/Th2 balance in a group of young people, and 3 clusters were formed with the following characteristics: 1) subjects with a higher prevalence of hyperglycemia (38%), dyslipidemia (38–75%), and insulin resistance (50%), as well as a higher percentage of Th1 cells and Th1/Th2 ratio, including elevated IFN-ɣ levels; 2) subjects with a lower prevalence of hyperglycemia (23%) and insulin resistance (15.4%), but a higher prevalence of dyslipidemia (8–85%) with a predominance of Th2 cells, and lower Th1/Th2 ratio; 3) subjects with a lower prevalence of hyperglycemia (6%), insulin resistance (41%), and dyslipidemia (10–63%), as well as a balance of Th1 and Th2 cells and lower Th1/Th2 ratio, including low IFN-ɣ levels. Positive correlations between Th1 cells with IFN-γ, IL-12, and IL-1β and between Th2 cells with IFN-γ, IL-2, and IL-4 were found (p < 0.05). A significant increase in Th1 cells was observed in the presence of hyperglycemia and high LDL-C levels, as well as increased Th2 cells in the absence of abdominal obesity and high blood pressure, including low HDL-C levels. The Th1/Th2 ratio was higher in the group with high cardiometabolic risk (p = 0.03).

Conclusion

Th1/Th2 balance is related to metabolic abnormalities that may occur in young population, and thus the timely identification of different phenotypes may help predict an increased cardiometabolic risk.

An interferon-related signature characterizes the whole blood transcriptome profile of insulin-resistant individuals—the CODAM study

Background

Worldwide, the prevalence of obesity and insulin resistance has grown dramatically. Gene expression profiling in blood represents a powerful means to explore disease pathogenesis, but the potential impact of inter-individual differences in a cell-type profile is not always taken into account. The objective of this project was to investigate the whole blood transcriptome profile of insulin-resistant as compared to insulin-sensitive individuals independent of inter-individual differences in white blood cell profile.

Results

We report a 3% higher relative amount of monocytes in the insulin-resistant individuals. Furthermore, independent of their white blood cell profile, insulin-resistant participants had (i) higher expression of interferon-stimulated genes and (ii) lower expression of genes involved in cellular differentiation and remodeling of the actin cytoskeleton.

Conclusions

We present an approach to investigate the whole blood transcriptome of insulin-resistant individuals, independent of their DNA methylation-derived white blood cell profile. An interferon-related signature characterizes the whole blood transcriptome profile of the insulin-resistant individuals, independent of their white blood cell profile. The observed signature indicates increased systemic inflammation possibly due to an innate immune response and whole-body insulin resistance, which can be a cause or a consequence of insulin resistance. Altered gene expression in specific organs may be reflected in whole blood; hence, our results may reflect obesity and/or insulin resistance-related organ dysfunction in the insulin-resistant individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12263-021-00702-7.

Immune cell profile and immune-related gene expression of obese peripheral blood and liver tissue

Obesity is associated with changes in immune cell subpopulations. However, tissue and blood obesity-responsive immune phenotypic pathways have not been contrasted. Here, the local niche immune cell population and gene expression in fatty liver is compared to peripheral blood of obese individuals. The Cibersort algorithm enumerated increased fractions of memory CD4⁺ T lymphocytes and reductions in natural killer and memory B cells in obese liver tissue and obese blood, with similar reductions found in nonalcoholic fatty liver disease tissue. Gene expression analysis identified inflammatory immune signatures of regulatory CD4⁺ T cells with inferred Th1, Th17, Th2, or Treg phenotypes that differed between liver and blood. Our study suggests that the local tissue-specific immune phenotype in the liver differs from the obese peripheral circulation, with the latter reflective of multisystemic persistent inflammation that is characteristic of obesity.

Adipocyte inflammation and pathogenesis of viral pneumonias: an overlooked contribution

Epidemiological evidence establishes obesity as an independent risk factor for increased susceptibility and severity to viral respiratory pneumonias associated with H1N1 influenza and SARS-CoV-2 pandemics. Given the global obesity prevalence, a better understanding of the mechanisms behind obese susceptibility to infection is imperative. Altered immune cell metabolism and function are often perceived as a key causative factor of dysregulated inflammation. However, the contribution of adipocytes, the dominantly altered cell type in obesity with broad inflammatory properties, to infectious disease pathogenesis remains largely ignored. Thus, skewing of adipocyte-intrinsic cellular metabolism may lead to the development of pathogenic inflammatory adipocytes, which shape the overall immune responses by contributing to either premature immunosenescence, delayed hyperinflammation, or cytokine storm in infections. In this review, we discuss the underappreciated contribution of adipocyte cellular metabolism and adipocyte-produced mediators on immune system modulation and how such interplay may modify disease susceptibility and pathogenesis of influenza and SARS-CoV-2 infections in obese individuals.

Obesity Correlates With Pronounced Aberrant Innate Immune Responses in Hospitalized Aged COVID-19 Patients

Both age and obesity are leading risk factors for severe coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Specifically, although most infections occur in individuals under the age of 55 years, 95% of hospitalizations, admissions to the intensive care unit, and deaths occur in those over the age of 55 years. Moreover, hospitalized COVID-19 patients have a higher prevalence of obesity. It is generally believed that chronic low-grade inflammation and dysregulated innate and adaptive immune responses that are associated with aging and obesity are responsible for this elevated risk of severe disease. However, the impact of advanced age and obesity on the host response to SARS-CoV-2 infection remains poorly defined. In this study, we assessed changes in the concentration of soluble immune mediators, IgG antibody titers, frequency of circulating immune cells, and cytokine responses to mitogen stimulation as a function of BMI and age. We detected significant negative correlations between BMI and myeloid immune cell subsets that were more pronounced in aged patients. Similarly, inflammatory cytokine production by monocytes was also negatively correlated with BMI in aged patients. These data suggest that the BMI-dependent impact on host response to SARS-CoV-2 is more pronounced on innate responses of aged patients.

Dendritic Cells and T Cell Subsets in the Development of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are associated with steatosis, inflammation and fibrosis. Liver dendritic cells (DCs) are usually tolerogenic in the sinusoidal milleu composed of immunosuppressive cytokines. In NAFLD and NASH, DCs become pro-inflammatory and modulate hepatic immune response. Murine liver DCs are three major subtypes: classical (lymphoid) cDC1 or the crosspresenters (CD8α+CD103+), classical (myeloid) cDC2 (CD11b+) and plasmacytoid pDCs (PDCA-1+Siglec-H+) and two additional subtypes or lymphoid + myeloid DCs and NKDCs. Similarly, human liver DCs are three subtypes or CD141+CLEC9A+, CD1c+ (BDCA1+) and pDCs (CD303+BDCA2+). Compared to blood human hepatic DCs are less immature and predominantly induce regulatory T cells (Tregs) and IL-4 secreting T cells (Th2). DCs polarize T cells into different Th types that are in interrelations in NAFLD/NASH. T helper 1 (Th1) (T-bet) cells are associated with adipose tissue inflammation. The differentiation of Th2 (GATA3) cells is induced by IL-4 DCs, increased in NAFLD. Similarly, Th17 cells (RORγt/ RORc) are increased in NAFLD and NASH. Tregs (FoxP3) are increased in the liver in steatosis and Th22 cells (AHR) are elevated in diabetes mellitus 2 (DM2) and adiposity. CD8+ T cells γδT cells and MAIT cells also contribute to liver inflammation.

T Cell Immunosenescence in Aging, Obesity, and Cardiovascular Disease

Although advances in preventive medicine have greatly improved prognosis, cardiovascular disease (CVD) remains the leading cause of death worldwide. This clearly indicates that there remain residual cardiovascular risks that have not been targeted by conventional therapies. The results of multiple animal studies and clinical trials clearly indicate that inflammation is the most important residual risk and a potential target for CVD prevention. The immune cell network is intricately regulated to maintain homeostasis. Ageing associated changes to the immune system occurs in both innate and adaptive immune cells, however T cells are most susceptible to this process. T-cell changes due to thymic degeneration and homeostatic proliferation, metabolic abnormalities, telomere length shortening, and epigenetic changes associated with aging and obesity may not only reduce normal immune function, but also induce inflammatory tendencies, a process referred to as immunosenescence. Since the disruption of biological homeostasis by T cell immunosenescence is closely related to the development and progression of CVD via inflammation, senescent T cells are attracting attention as a new therapeutic target. In this review, we discuss the relationship between CVD and T cell immunosenescence associated with aging and obesity.

Obesity, a major risk factor for immunity and severe outcomes of COVID-19

An influenza-like virus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for COVID-19 disease and spread worldwide within a short time. COVID-19 has now become a significant concern for public health. Obesity is highly prevalent worldwide and is considered a risk factor for impairing the adaptive immune system. Although diabetes, hypertension, cardiovascular disease (CVD), and renal failure are considered the risk factors for COVID-19, obesity is not yet well-considered. The present study approaches establishing a systemic association between the prevalence of obesity and its impact on immunity concerning the severe outcomes of COVID-19 utilizing existing knowledge. Overall study outcomes documented the worldwide prevalence of obesity, its effects on immunity, and a possible underlying mechanism covering obesity-related risk pathways for the severe outcomes of COVID-19. Overall understanding from the present study is that being an immune system impairing factor, the role of obesity in the severe outcomes of COVID-19 is worthy.

The Immunometabolic Roles of Various Fatty Acids in Macrophages and Lymphocytes

Macrophages and lymphocytes demonstrate metabolic plasticity, which is dependent partly on their state of activation and partly on the availability of various energy yielding and biosynthetic substrates (fatty acids, glucose, and amino acids). These substrates are essential to fuel-based metabolic reprogramming that supports optimal immune function, including the inflammatory response. In this review, we will focus on metabolism in macrophages and lymphocytes and discuss the role of fatty acids in governing the phenotype, activation, and functional status of these important cells. We summarize the current understanding of the pathways of fatty acid metabolism and related mechanisms of action and also explore possible new perspectives in this exciting area of research.

Obesity-related IL-18 Impairs Treg Function and Promotes Lung Ischemia-reperfusion Injury

RATIONALE

Primary graft dysfunction (PGD) is a severe form of acute lung injury, leading to increased early morbidity and mortality after lung transplantation. Obesity is a major health problem, and recipient obesity is one of the most significant risk factors for developing PGD.

OBJECTIVES

We hypothesized that T-regulatory (Treg) cells are able to dampen early ischemia/reperfusion events and thereby decrease risk of PGD, whereas that action is impaired in obese recipients.

METHODS

We evaluated Treg, T cells and inflammatory markers, plus clinical data, in 79 lung and 41 liver or kidney transplant recipients and studied two groups of mice on high fat diet (HFD), who developed ("inflammatory" HFD) or not ("healthy" HFD) low-grade inflammation with decreased Treg function.

RESULTS

We identified increased levels of IL-18 as a previously unrecognized mechanism that impairs Treg suppressive function in obese individuals. IL-18 decreases levels of FOXP3, the key Treg transcription factor, decreases FOXP3 di- and oligomerization and increases the ubiquitination and proteasomal degradation of FOXP3. IL-18-treated Tregs or Treg from obese mice fail to control PGD, while IL-18 inhibition ameliorates lung inflammation. The IL-18 driven impairment in Treg suppressive function pre-transplant was associated with increased risk and severity of PGD in clinical lung transplant recipients.

CONCLUSION

Obesity-related IL-18 induces Treg dysfunction that may contribute to the pathogenesis of PGD. Evaluation of Treg suppressive function along with IL-18 levels may serve as screening tools to identify pre-transplant obese recipients with increased risk of PGD.

Maternal Death Caused by Severe-Critical COVID-19 in Jakarta: Case Series

BACKGROUND: As of January 2021, Indonesia had the 21st highest number of total COVID-19 cases and the 17th highest total deaths among all countries. COVID-19 infection in pregnant women seems to negatively affect both maternal and neonatal outcomes. CASE REPORT: We describe four cases of pregnant women confirmed with severe and critical COVID-19 that resulted in maternal death from November until December 2020. The first case was complicated with thrombocytopenia, her condition quickly deteriorated post-delivery. Pulmonary embolism was suspected as the cause of death. Second and third cases were complicated with preeclampsia, obesity, and advanced maternal age. Second case came in sepsis condition. Her SARS CoV-2 RTPCR swab test came out after her death. Third patient did not have COVID-19 symptoms at admission. She starts having symptoms on second day and was confirmed positive a day after. She falls in septic shock. Fourth patient has history of fever, cough, and dyspnea. She was confirmed positive on first day and her condition worsened, diagnosed with bacterial co-infection sepsis on day eight. All patients underwent cesarean section. CONCLUSION: Limited information and studies for COVID-19 management in pregnant women are challenging for obstetricians. Management should be individualized weighing the benefit and risks in presence of comorbidities or accompanying disease.

Effects of Morbid Obesity and Metabolic Syndrome on the Composition of Circulating Immune Subsets

Morbid obesity is characterized by chronic, low-grade inflammation, which is associated with ‘inflamm-aging’. The presence of metabolic syndrome (MetS) might accelerate this phenomenon of metaflammation. In this study, we assessed the effects of morbid obesity and MetS on the composition of a broad spectrum of immune cells present within the circulation. A total of 117 morbidly obese patients (MOP) without MetS (MetS-), 127 MOP with MetS (MetS+) and 55 lean controls (LC) were included in this study. Absolute numbers of T cell, B cell, NK cell and monocyte subsets were assessed within peripheral blood using flow cytometry. Both absolute cell numbers and proportion of cells were evaluated correcting for covariates age, body mass index and cytomegalovirus serostatus. Although the absolute number of circulating CD4+ T cells was increased in the MetS+ group, the CD4+ T cell composition was not influenced by MetS. The CD8+ T cell and B cell compartment contained more differentiated cells in the MOP, but was not affected by MetS. Even though the absolute numbers of NK cells and monocytes were increased in the MOP as compared to LC, there was no difference in proportions of NK and monocyte subsets between the three study groups. In conclusion, although absolute numbers of CD4+ and CD8+ T cells, B cells, NK cells and monocytes are increased in MOP, obesity-induced effects of the composition of the immune system are confined to a more differentiated phenotype of CD8+ T cells and B cells. These results were not affected by MetS.

Adipose Tissue Immunomodulation and Treg/Th17 Imbalance in the Impaired Glucose Metabolism of Children with Obesity

In the last few decades, obesity has increased dramatically in pediatric patients. Obesity is a chronic disease correlated with systemic inflammation, characterized by the presence of CD4 and CD8 T cell infiltration and modified immune response, which contributes to the development of obesity related diseases and metabolic disorders, including impaired glucose metabolism. In particular, Treg and Th17 cells are dynamically balanced under healthy conditions, but imbalance occurs in inflammatory and pathological states, such as obesity. Some studies demonstrated that peripheral Treg and Th17 cells exhibit increased imbalance with worsening of glucose metabolic dysfunction, already in children with obesity. In this review, we considered the role of adipose tissue immunomodulation and the potential role played by Treg/T17 imbalance on the impaired glucose metabolism in pediatric obesity. In the patient care, immune monitoring could play an important role to define preventive strategies of pediatric metabolic disease treatments.

The Immunophenotyping Changes of Peripheral CD4+ T Lymphocytes and Inflammatory Markers of Class III Obesity Subjects After Laparoscopic Gastric Sleeve Surgery - A Follow-Up Study

Purpose

Obesity is a chronic disorder characterized by a low-grade inflammatory state and immune cell irregularities. The study aimed to follow up on the changes in the peripheral CD4+ T lymphocytes and the pro-inflammatory cytokines; IL-6, TNF-alpha, MCP-1, and IL-10 at baseline and 12 weeks post-surgical intervention by the laparoscopic gastric sleeve (LGS) in morbidly obese patients (class III obesity subjects).

Materials and Methods

A prospective longitudinal research included 24 class III obesity subjects with a BMI > 40 kg/m². The subjects were enrolled from the Metabolic/Surgical Department at Hamad Medical Corporation (HMC)-Qatar. Fasting blood samples were collected at admission to LGS for weight loss and after 12 weeks of LGS. The immunophenotype of CD4+ T-cell populations; naïve (CD45RA⁺and CD27⁺), central memory T cells (CD45RO⁺ and CD27⁺), and effector memory (CD45RO⁺and CD27^-) and T-regulatory cell (CD4+CD25+ FoxP3+) were identified using flow cytometry. Plasma pro-inflammatory cytokines and adipokines were evaluated. A control group of lean subjects was used to compare changes of T-regulatory and inflammatory biomarkers with postoperative changes in obese patients.

Results

The means (SD) of age and BMI of class III obesity subjects was 32.32 (8.36) years and 49.02 (6.28) kg/m^2, respectively. LGS caused a significant reduction in BMI by 32%, p<0.0001. LGS intervention significantly decreased CD4+ T-lymphocytes and effector memory (TEM) cells but increased T-regulatory (Treg), naïve, and central memory (TCM) cells, with all p values < 0.05. The increase of Treg cells postoperative is significantly lower compared to lean subjects, p < 0.05. A significant reduction of plasma IL-6, TNF-α, and MCP-1, but IL-10 significantly increased after LGS, with all p<0.05. Adiponectin/leptin ratio improved after LGS by 2.9 folds, p<0.0001.

Conclusion

Weight loss by LGS accomplished a substantial rise of Treg and decreased EM T-lymphocytes with a shift from pro-inflammatory to the anti-inflammatory pattern.

Fasting alters the gut microbiome reducing blood pressure and body weight in metabolic syndrome patients

Periods of fasting and refeeding may reduce cardiometabolic risk elevated by Western diet. Here we show in the substudy of NCT02099968, investigating the clinical parameters, the immunome and gut microbiome exploratory endpoints, that in hypertensive metabolic syndrome patients, a 5-day fast followed by a modified Dietary Approach to Stop Hypertension diet reduces systolic blood pressure, need for antihypertensive medications, body-mass index at three months post intervention compared to a modified Dietary Approach to Stop Hypertension diet alone. Fasting alters the gut microbiome, impacting bacterial taxa and gene modules associated with short-chain fatty acid production. Cross-system analyses reveal a positive correlation of circulating mucosa-associated invariant T cells, non-classical monocytes and CD4⁺ effector T cells with systolic blood pressure. Furthermore, regulatory T cells positively correlate with body-mass index and weight. Machine learning analysis of baseline immunome or microbiome data predicts sustained systolic blood pressure response within the fasting group, identifying CD8⁺ effector T cells, Th17 cells and regulatory T cells or Desulfovibrionaceae, Hydrogenoanaerobacterium, Akkermansia, and Ruminococcaceae as important contributors to the model. Here we report that the high-resolution multi-omics data highlight fasting as a promising non-pharmacological intervention for the treatment of high blood pressure in metabolic syndrome patients.

Nutritional modification including fasting has been shown to reduce cardiometabolic risk linked to western diet. Here the authors show implementation of fasting resulted in alterations to the intestinal microbiota, and circulating immune cells, improving blood pressure and body weight in patients with metabolic syndrome.

Serum myokine levels after linear and flexible non-linear periodized resistance training in overweight sedentary women

This study compared the capacity of linear-(LP) and non-linear periodized (NLP) resistance training to improve select myokines and metabolic parameters in overweight sedentary women. An additional purpose was to compare these variables between the overweight and lean women. Fitness- and age-matched overweight women between 28 and 43 years old were randomly allocated to LP (body fat [BF]% = 38.7 ± 2.6, n = 10), NLP (BF% = 39.3 ± 2.4, n = 9) and control (BF% = 39.8 ± 2.6, n = 9) groups. Lean women (BF% = 29.1 ± 2.3, n = 16) matched for age and fitness were also included for baseline comparison. Resistance training programmes (12 weeks, 3 d.wk^-1, 9 exercises, 60-90% of 1-repetition maximum [1RM]) were performed with different periodization schemes. Glucose, insulin, interleukin (IL)-7, IL-15, and insulin-like growth factor (IGF)-1 levels were measured at baseline and after training. Overweight subjects had significantly lower IL-15, IGF-1 and higher insulin, glucose, and insulin resistance (homeostasis model assessment, HOMA-IR) than lean subjects at baseline (all, P < .05). IL-15 and VO₂max increased significantly after NLP compared with CON, which was accompanied by a significant decrease in HOMA-IR (all, P < .03). Muscular endurance improved significantly in both models after training compared to CON (all, P < .01), but it increased more in NLP than in LP (P = .01). Both training protocols were equally effective at reducing BF% and increasing IGF-1, IL-7, muscle mass and bench press 1RM (P < .01). It appears that LP and NLP are both effective strategies for improving health markers in overweight women, but LP is not as effective as NLP to improve IL-15, HOMA-IR and aerobic capacity.Highlights Overweight women had a significantly lower IL-15 and IGF-1 compared to lean encounters, but no significant difference was noted for maximal strength, aerobic capacity, muscle mass, IL-7 and neutrophil/lymphocyte ratio.Twelve weeks of either linear or flexible non-linear periodized resistance training resulted in reduction in BF% and neutrophil/lymphocyte ratio, and increased IGF-1, IL-7, muscle mass and bench press 1RM, with no difference between the two training protocols.Linear protocol is not as effective as non-linear protocol to improve IL-15, HOMA-IR and aerobic capacity.

Lifestyle exercise attenuates immunosenescence; flow cytometry analysis

Background

Interaction of physical activity and overall immune profile is very complex and depends on the intensity, duration and frequency of undertaken physical activity, the exposure to cytomegalovirus (CMV) infection and the age-related changes in the immune system. Daily physical activity, which particularly influences immunity, declines dramatically with age. Therefore, the aim of the study was to explain whether physical activity sustained throughout life can attenuate or reverse immunosenescence.

Methods

Ninety-nine older adults (60–90 years) were recruited for the study. According to the 6-min walk test (6WMT), the Åstrand-Ryhming bike test (VO₂max) and Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire, the individuals were classified as physically active (n = 34) and inactive (n = 20) groups. The analysis of T lymphocytes between active vs. inactive participants was performed using eight-parameter flow cytometry.

Results

Analysis of the baseline peripheral naïve and memory T lymphocytes showed a significant relationship of lifestyle exercise with the CD4/CD8 ratio. Above 50% of physically active participants demonstrated the CD4/CD8 ratio ≥ 1 or ≤ 2.5 contrary to the inactive group who showed the ratio < 1. The older adults with the result of 6WMT > 1.3 m/s and VO₂max > 35 mL/kg/min had a significantly higher CD4⁺CD45RA⁺ T lymphocyte percentage and also a higher ratio of CD4⁺CD45RA⁺/CD4⁺CD45RO⁺. Interestingly, in active older adults with IgG CMV⁺ (n = 30) the count of CD4⁺CD45RA⁺ T lymphocytes was higher than in the inactive group with IgG CMV⁺ (n = 20).

Conclusion

Based on the flow cytometry analysis, we concluded that lifestyle exercise could lead to rejuvenation of the immune system by increasing the percentage of naïve T lymphocytes or by reducing the tendency of the inverse CD4/CD8 ratio.

Extensive longitudinal immune profiling reveals sustained innate immune activation in COVID-19 patients with unfavorable outcome

COVID-19 differs substantially between individuals, ranging from mild to severe or even fatal. Heterogeneity in the immune response against SARS-COV-2 likely contributes to this. Therefore, we explored the temporal dynamics of key cellular and soluble mediators of innate and adaptive immune activation in relation to COVID-19 severity and progression.

Forty-four patients with a PCR-proven diagnosis of COVID-19 were included. Extensive cellular (leukocytes and T-lymphocyte subsets) and serological immune profiling (cytokines, soluble cell surface molecules, and SARS-CoV-2 antibodies) was performed at hospital admission and every 3–4 days during hospitalization. Measurements and disease outcome were compared between patients with an unfavorable (IC admission and/or death) and favorable (all others) outcome.

Patients with an unfavorable outcome had higher leukocyte numbers at baseline, mostly due to increased neutrophils, whereas lymphocyte and monocyte numbers were reduced. CRP, IL-6, CCL2, CXCL10, and GM-CSF levels were higher at baseline in the unfavorable group, whereas IL-7 levels were lower. SARS-CoV-2 antibodies were more frequently absent in the unfavorable group. Longitudinal analysis revealed delayed kinetics of activated CD4 and CD8 T-lymphocyte subsets in the unfavorable group. Furthermore, whereas CRP, IL-6, CXCL10, and GM-CSF declined in the favorable group, these cytokines declined with delayed kinetics, remained increased, or even increased further in the unfavorable group.

Our data indicate a state of increased innate immune activation in COVID19-patients with an unfavorable outcome at hospital admission, which remained over time, as compared with patients with a favorable outcome.

Clinical management of patients with genetic obesity during COVID-19 pandemic: position paper of the ESE Growth & Genetic Obesity COVID-19 Study Group and Rare Endo-ERN main thematic group on Growth and Obesity

This article aims to provide guidance on prevention and treatment of COVID-19 in patients with genetic obesity. Key principals of the management of patients with genetic obesity during COVID-19 pandemic for patients that have contracted COVID-19 are to be aware of: possible adrenal insufficiency (e.g., POMC deficiency, PWS); a more severe course in patients with concomitant immunodeficiency (e.g., LEP and LEPR deficiency), although defective leptin signalling could also be protective against the pro-inflammatory phenotype of COVID-19; disease severity being masked by insufficient awareness of symptoms in syndromic obesity patients with intellectual deficit (in particular PWS); to adjust medication dose to increased body size, preferably use dosing in m2; the high risk of malnutrition in patients with Sars-Cov2 infection, even in case of obesity. Key principals of the obesity management during the pandemic are to strive for optimal obesity management and a healthy lifestyle within the possibilities of the regulations to prevent weight (re)gain and to address anxiety within consultations, since prevalence of anxiety for COVID-19 is underestimated.

Inflammation and Wnt Signaling: Target for Immunomodulatory Therapy?

Wnt proteins comprise a large family of highly conserved glycoproteins known for their role in development, cell fate specification, tissue regeneration, and tissue homeostasis. Aberrant Wnt signaling is linked to developmental defects, malignant transformation, and carcinogenesis as well as to inflammation. Mounting evidence from recent research suggests that a dysregulated activation of Wnt signaling is involved in the pathogenesis of chronic inflammatory diseases, such as neuroinflammation, cancer-mediated inflammation, and metabolic inflammatory diseases. Recent findings highlight the role of Wnt in the modulation of inflammatory cytokine production, such as NF-kB signaling and in innate defense mechanisms as well as in the bridging of innate and adaptive immunity. This sparked the development of novel therapeutic treatments against inflammatory diseases based on Wnt modulation. Here, we summarize the role and function of the Wnt pathway in inflammatory diseases and focus on Wnt signaling as underlying master regulator of inflammation that can be therapeutically targeted.

Immunological substrates of depressive symptoms in patients with severe obesity: An exploratory study

In this pilot study, we explored the immune phenotype of patients with severe obesity and comorbid depressive symptoms compared to non-depressed patients with obesity and normal-weight controls. Immune cell subsets were analysed by flow cytometry and depressive symptoms assessed using the Patient Health Questionnaire (PHQ-9). Cell frequencies were correlated with depressive symptom scores and waist-to-hip ratio (WHR). Patients with obesity and comorbid depression showed significantly lower numbers of circulating cytotoxic natural killer cells, dendritic cells and CD8⁺ effector memory T cells, compared to normal-weight controls. Regulatory T cells and CD4⁺ central memory T cells were increased compared to non-depressed patients with obesity and compared to normal-weight controls, respectively. Frequencies of cytotoxic natural killer cells and CD4⁺ central memory T cells significantly correlated with PHQ-9 scores, but not with WHR. Reduced numbers of dendritic cells were observed in both patient groups with obesity and correlated with PHQ-9 scores and WHR. These findings provide evidence for an altered immune composition in comorbid obesity and depression, supporting a pathobiological overlap between the two disorders.

Increasing Imbalance of Treg/Th17 Indicates More Severe Glucose Metabolism Dysfunction in Overweight/obese Patients

BACKGROUND

Chronic low-grade inflammation and dysfunction of metabolism has been reported to be involved in obesity. Regulatory T cell (Treg) and helper T cell 17 (Th17) are involved in chronic inflammatory diseases. Impaired balance of Treg/Th17 is one of the major factors contributing to inflammatory status in obesity.

METHODS

Overweight/obese patients (n = 80) were recruited and classified into three subgroups: normal glucose tolerance group (NGT, n = 32), impaired glucose regulation group (IGR, n = 19) and type two diabetes mellitus group (T2DM, n = 29). Healthy individuals were paired as normal control group (NC, n = 37). We used flow cytometry to test the frequencies of circulating Treg and Th17 cells of all subjects. Serum IL-6, IL-10, TNF-α, IL-17A levels were detected by cytometric bead array and clinical information was extracted from medical records.

RESULTS

In group IGR and T2DM, we revealed a severe decrease in peripheral ratio of Treg/Th17 compared with NC, but no significant difference was seen in group NGT. The serum level of IL-6 in group NGT and T2DM was higher than healthy subjects. The FPG and HbA1c levels were negatively correlated with the ratio of Treg/Th17 in overweight/obese patients. ROC curve analysis revealed that peripheral Treg/Th17 ratio <1.255 was a risk factor for prediabetes and diabetes in overweight/obese patients.

CONCLUSION

Peripheral Treg/Th17 imbalance exists in overweight/obese patients with IGR or T2DM and peripheral Treg/Th17 imbalance might be a risk factor for prediabetes and diabetes in overweight/obese patients.

Obesity and immune status in children

PURPOSE OF REVIEW

Childhood obesity, with persistent chronic inflammation, is a worldwide epidemic. Obesity causes dysregulation throughout the immune system, affecting the balance and levels of cytokines, adipokines, and innate and adaptive immune cells. The present review focuses on the impact of obesity on immune function in children: altering the baseline activation state of immune cells and affecting the ability of the host to combat pathogens and malignancy and respond appropriately to vaccination.

RECENT FINDINGS

Obesity causes dysregulation of the immune system. Single-cell RNA-sequencing of adipose tissue and resident immune cells is quantifying the impact of obesity on the frequency of immune cell subsets and their states. The system-wide alterations in immune function in obesity are most evident upon perturbation, including the response to infection (e.g. increased risk of severe COVID-19 in the ongoing pandemic), vaccination, and malignancy. However, mechanistic research in pediatric obesity is limited and this impacts our ability to care for these children.

SUMMARY

We must better understand baseline and perturbed immune health in obese children to determine how to account for altered frequency and function of humoral and cellular immune components in acute infection, during vaccine design and when considering therapeutic options for this complex, medically vulnerable group.

Maternal obesity is associated with phenotypic alterations in fetal immune cells by single-cell mass cytometry

PROBLEM

Prenatal exposure to metabolic dysregulation arising from maternal obesity can have negative health consequences in post-natal life. To date, the specific effects of maternal obesity on fetal immunity at a cellular level have not been well characterized.

METHOD OF STUDY

Using cord blood mononuclear cells (CBMCs) and cord plasma (n = 9/group) isolated from infants born to women with a high body mass index (BMI>25kg/m² ) compared to women with a normal BMI (18-25kg/m² ), we evaluated differences in immune cell populations using single-cell mass cytometry (CyTOF). CBMCs were matched according to potentially confounding variables, such as maternal and gestational age, ethnicity, smoking status, and gravidity. Statistical results were adjusted for fetal sex. Data were analyzed by viSNE and FlowSOM softwares in Cytobank^™ .

RESULTS

In newborn CBMCs from women with high BMI, we observed changes in frequency and phenotype of immune cell populations, including significant increases in CD4⁺ T cells and decreases in myeloid cell populations. IL-12p40 and MDC concentrations were significantly elevated in the high BMI group compared to control.

CONCLUSION

This study demonstrates an association between maternal obesity and fetal immunity. Our results warrant following long-term immunologic outcomes and associated clinical risks in children born to women with a high pre-pregnancy BMI.

Individuals with obesity and COVID-19: A global perspective on the epidemiology and biological relationships

The linkage of individuals with obesity and COVID-19 is controversial and lacks systematic reviews. After a systematic search of the Chinese and English language literature on COVID-19, 75 studies were used to conduct a series of meta-analyses on the relationship of individuals with obesity-COVID-19 over the full spectrum from risk to mortality. A systematic review of the mechanistic pathways for COVID-19 and individuals with obesity is presented. Pooled analysis show individuals with obesity were more at risk for COVID-19 positive, >46.0% higher (OR = 1.46; 95% CI, 1.30-1.65; p < 0.0001); for hospitalization, 113% higher (OR = 2.13; 95% CI, 1.74-2.60; p < 0.0001); for ICU admission, 74% higher (OR = 1.74; 95% CI, 1.46-2.08); and for mortality, 48% increase in deaths (OR = 1.48; 95% CI, 1.22-1.80; p < 0.001). Mechanistic pathways for individuals with obesity are presented in depth for factors linked with COVID-19 risk, severity and their potential for diminished therapeutic and prophylactic treatments among these individuals. Individuals with obesity are linked with large significant increases in morbidity and mortality from COVID-19. There are many mechanisms that jointly explain this impact. A major concern is that vaccines will be less effective for the individuals with obesity.

Obesity-associated T-cell and macrophage activation improve partly after a lifestyle intervention

BACKGROUND

The relation between low-grade inflammation and metabolic dysfunction in obesity is not fully explored.

OBJECTIVE

To evaluate immune parameters in the obese state and after a lifestyle intervention program.

METHODS

Patients with obesity (n = 87) from an academic obesity clinic were compared with controls with regard to macrophage and T-cell activation (reflected by serum levels of soluble CD163 (sCD163) and soluble IL-2 receptor (sIL-2R), respectively), and an array of cytokines, chemokines, and growth factors. In addition, these parameters and regulatory T-cells (Treg), were studied in 27 patients who followed a 75-week lifestyle intervention (dietary advice, exercise, and psychoeducation).

RESULTS

Mean sIL-2R and sCD163 levels were higher in patients than controls (sIL-2R:2884 ± 936 pg/ml vs. 2207 ± 813 pg/ml, p = 0.001; sCD163:1279 ± 580 pg/ml vs. 661 ± 271 pg/ml, p < 0.0001 respectively). Patients with metabolic syndrome (MetS) had higher sCD163 than those without (1467 ± 656 pg/ml vs. 1103 ± 438 pg/ml). Patients had higher IL-1β, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-15, IL-17A, MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, G-CSF, GM-CSF, FGF, IFN-γ, and TNF-α than controls, whereas VEGF-A, PDGF-BB, and eotaxin were lower. Upon intervention, sIL-2R decreased while peripheral Treg frequencies increased within the reference range (p = 0.042 and p = 0.005 respectively). The sIL-2R decrease correlated to a decrease in waist circumference (rho = 0.388, p = 0.045) and in trend to a decrease in MetS components (rho = 0.345, p = 0.078). The Treg increase was unrelated to weight loss or metabolic improvement. Mean sCD163 did not change significantly upon intervention, nor did the cytokines, chemokines, and growth factors (except IP-10/CXCL10).

CONCLUSION

In obesity, T-cell homeostasis improves after a lifestyle intervention. Immunologic alterations can occur independently of metabolic improvement.

Increased systemic inflammation and altered distribution of T-cell subsets in postmenopausal women

Aim

To investigate markers of systemic inflammation in pre- and postmenopausal women and identify possible predictors of systemic inflammation with menopause.

Methods

Cross-sectional study of 69 healthy women between 45- and 60 years. Blood samples were collected to assess leukocyte subsets and plasma cytokines. MRI and DXA scans were performed to assess body composition. Through uni- and multivariate analyses, follicle-stimulating hormone (FSH), visceral fat mass and age were evaluated as predictors of systemic inflammation in relation to menopause.

Results

Postmenopausal women tended to have higher leukocyte counts (5.4 x10⁹ vs. 4.9 x10⁹ cells/l, p = 0.05) reflected in increased total lymphocytes (1.8 x10⁹ vs. 1.6 x10⁹ cells/l, p = 0.01) and monocytes (0.5 x10⁹ vs. 0.4 x10⁹ cells/l, p = 0.02), compared to premenopausal women. Increased visceral fat mass was a strong predictor of high leukocyte subsets. Postmenopausal women had higher plasma TNF-α (2.24 vs. 1.91 pg/ml, p = 0.01) and IL-6 (0.45 vs. 0.33 pg/ml, p = 0.004) compared to premenopausal women and high FSH was a significant predictor of increased plasma TNF-α, IL-1β and IL-6. Menopause was further associated with increased T-cells (1,336 vs. 1,128 cells/μl, p = 0.04) reflected in significantly higher counts of exhausted-, senescent-, and memory CD4+ T-cell subsets.

Conclusions

Menopause is associated with increased systemic inflammation as well as exhausted- and senescent T-cells. We suggest, that both increased visceral fat mass and declining sex hormone levels might contribute to postmenopausal systemic inflammation and calls for further large-scale studies to confirm these findings.