Excess of body weight is associated with accelerated T-cell senescence in hospitalized COVID-19 patients.

BACKGROUND: Several risk factors have been involved in the poor clinical progression of coronavirus disease-19 (COVID-19), including ageing, and obesity. SARS-CoV-2 may compromise lung function through cell damage and paracrine inflammation; and obesity has been associated with premature immunosenescence, microbial translocation, and dysfunctional innate immune responses leading to poor immune response against a range of viruses and bacterial infections. Here, we have comprehensively characterized the immunosenescence, microbial translocation, and immune dysregulation established in hospitalized COVID-19 patients with different degrees of body weight. RESULTS: Hospitalised COVID-19 patients with overweight and obesity had similarly higher plasma LPS and sCD14 levels than controls (all p < 0.01). Patients with obesity had higher leptin levels than controls. Obesity and overweight patients had similarly higher expansions of classical monocytes and immature natural killer (NK) cells (CD56+CD16-) than controls. In contrast, reduced proportions of intermediate monocytes, mature NK cells (CD56+CD16+), and NKT were found in both groups of patients than controls. As expected, COVID-19 patients had a robust expansion of plasmablasts, contrasting to lower proportions of major T-cell subsets (CD4 + and CD8+) than controls. Concerning T-cell activation, overweight and obese patients had lower proportions of CD4+CD38+ cells than controls. Contrasting changes were reported in CD25+CD127low/neg regulatory T cells, with increased and decreased proportions found in CD4+ and CD8+ T cells, respectively. There were similar proportions of T cells expressing checkpoint inhibitors across all groups. We also investigated distinct stages of T-cell differentiation (early, intermediate, and late-differentiated - TEMRA). The intermediate-differentiated CD4 + T cells and TEMRA cells (CD4+ and CD8+) were expanded in patients compared to controls. Senescent T cells can also express NK receptors (NKG2A/D), and patients had a robust expansion of CD8+CD57+NKG2A+ cells than controls. Unbiased immune profiling further confirmed the expansions of senescent T cells in COVID-19. CONCLUSIONS: These findings suggest that dysregulated immune cells, microbial translocation, and T-cell senescence may partially explain the increased vulnerability to COVID-19 in subjects with excess of body weight.

Endotoxin tolerance and low activation of TLR-4/NF-κB axis in monocytes of COVID-19 patients.

Higher endotoxin in the circulation may indicate a compromised state of host immune response against coinfections in severe COVID-19 patients. We evaluated the inflammatory response of monocytes from COVID-19 patients after lipopolysaccharide (LPS) challenge. Whole blood samples of healthy controls, patients with mild COVID-19, and patients with severe COVID-19 were incubated with LPS for 2 h. Severe COVID-19 patients presented higher LPS and sCD14 levels in the plasma than healthy controls and mild COVID-19 patients. In non-stimulated in vitro condition, severe COVID-19 patients presented higher inflammatory cytokines and PGE-2 levels and CD14 + HLA-DRlow monocytes frequency than controls. Moreover, severe COVID-19 patients presented higher NF-κB p65 phosphorylation in CD14 + HLA-DRlow, as well as higher expression of TLR-4 and NF-κB p65 phosphorylation in CD14 + HLA-DRhigh compared to controls. The stimulation of LPS in whole blood of severe COVID-19 patients leads to lower cytokine production but higher PGE-2 levels compared to controls. Endotoxin challenge with both concentrations reduced the frequency of CD14 + HLA-DRlow in severe COVID-19 patients, but the increases in TLR-4 expression and NF-κB p65 phosphorylation were more pronounced in both CD14 + monocytes of healthy controls and mild COVID-19 patients compared to severe COVID-19 group. We conclude that acute SARS-CoV-2 infection is associated with diminished endotoxin response in monocytes. KEY MESSAGES: Severe COVID-19 patients had higher levels of LPS and systemic IL-6 and TNF-α. Severe COVID-19 patients presented higher CD14+HLA-DRlow monocytes. Increased TLR-4/NF-κB axis was identified in monocytes of severe COVID-19. Blunted production of cytokines after whole blood LPS stimulation in severe COVID-19. Lower TLR-4/NF-κB activation in monocytes after LPS stimulation in severe COVID-19.

Systemic redox imbalance in severe COVID-19 patients.

The aim of this study was to evaluate the systemic redox state and inflammatory markers in intensive care unit (ICU) or non-ICU severe COVID-19 patients during the hospitalization period. Blood samples were collected at hospital admission (T1) (Controls and COVID-19 patients), 5-7 days after admission (T2: 5-7 days after hospital admission), and at the discharge time from the hospital (T3: 0-72 h before leaving hospital or death) to analyze systemic oxidative stress markers and inflammatory variables. The reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) were analyzed in peripheral granulocytes and monocytes. THP-1 human monocytic cell line was incubated with plasma from non-ICU and ICU COVID-19 patients and cell viability and apoptosis rate were analyzed. Higher total antioxidant capacity, protein oxidation, lipid peroxidation, and IL-6 at hospital admission were identified in both non-ICU and ICU COVID-19 patients. ICU COVID-19 patients presented increased C-reactive protein, ROS levels, and protein oxidation over hospitalization period compared to non-ICU patients, despite increased antioxidant status. Granulocytes and monocytes of non-ICU and ICU COVID-19 patients presented lower MMP and higher ROS production compared to the healthy controls, with the highest values found in ICU COVID-19 group. Finally, the incubation of THP-1 cells with plasma acquired from ICU COVID-19 patients at T3 hospitalization period decreased cell viability and apoptosis rate. In conclusion, disturbance in redox state is a hallmark of severe COVID-19 and is associated with cell damage and death.

Potential Anticarcinogenic Effects From Plasma of Older Adults After Exercise Training: An Exploratory Study.

Aim: To evaluate the impact of exercise training plasma on in vitro prostate cancer cell viability and proliferation. Methods: PC3 prostate cancer cells were incubated with plasma obtained from young men with high and low physical fitness (PF) (high PF, n = 5; low PF, n = 5) and with the plasma collected from institutionalized older adults (n = 8) before and after multimodal exercise training. Cell viability and proliferation, mitochondria membrane polarization, reactive oxygen species (ROS) generation, and apoptosis were evaluated after the cell treatment with plasma. Systemic cytokines were evaluated in the plasma of institutionalized older adults submitted to an exercise training protocol. Results: Plasma from high-PF men lowers both cell viability and proliferation after the incubation time. PC3 cells also presented lower cell viability and diminished rates of cell proliferation after the incubation with post-training plasma samples of the older adults. The incubation of PC3 cells with post-training plasma of older adults depolarized the mitochondrial membrane potential and increased mitochondrial reactive oxygen species production. Post-training plasma did not change apoptosis or necrosis rates in the PC3 cell line. Multimodal exercise training increased the plasma levels of IL-2, IL-10, IFN-α, and FGF-1 and decreased TNF-α concentrations in institutionalized older adults. Conclusion: Adaptations in blood factors of institutionalized older adults may alter cell viability and proliferation by targeting mitochondrial ROS in a prostate cancer cell line.

Alterations in CD39/CD73 axis of T cells associated with COVID-19 severity.

Purinergic signaling modulates immune function and is involved in the immunopathogenesis of several viral infections. This study aimed to investigate alterations in purinergic pathways in coronavirus disease 2019 (COVID-19) patients. Mild and severe COVID-19 patients had lower extracellular adenosine triphosphate and adenosine levels, and higher cytokines than healthy controls. Mild COVID-19 patients presented lower frequencies of CD4+ CD25+ CD39+ (activated/memory regulatory T cell [mTreg]) and increased frequencies of high-differentiated (CD27- CD28- ) CD8+ T cells compared with healthy controls. Severe COVID-19 patients also showed higher frequencies of CD4+ CD39+ , CD4+ CD25- CD39+ (memory T effector cell), and high-differentiated CD8+ T cells (CD27- CD28- ), and diminished frequencies of CD4+ CD73+ , CD4+ CD25+ CD39+ mTreg cell, CD8+ CD73+ , and low-differentiated CD8+ T cells (CD27+ CD28+ ) in the blood in relation to mild COVID-19 patients and controls. Moreover, severe COVID-19 patients presented higher expression of PD-1 on low-differentiated CD8+ T cells. Both severe and mild COVID-19 patients presented higher frequencies of CD4+ Annexin-V+ and CD8+ Annexin-V+ T cells, indicating increased T-cell apoptosis. Plasma samples collected from severe COVID-19 patients were able to decrease the expression of CD73 on CD4+ and CD8+ T cells of a healthy donor. Interestingly, the in vitro incubation of peripheral blood mononuclear cell from severe COVID-19 patients with adenosine reduced the nuclear factor-κB activation in T cells and monocytes. Together, these data add new knowledge to the COVID-19 immunopathology through purinergic regulation.

Increased LPS levels coexist with systemic inflammation and result in monocyte activation in severe COVID-19 patients.

Mucosal barrier alterations may play a role in the pathogenesis of several diseases, including COVID-19. In this study we evaluate the association between bacterial translocation markers and systemic inflammation at the earliest time-point after hospitalization and at the last 72 h of hospitalization in survivors and non-survivors COVID-19 patients. Sixty-six SARS-CoV-2 RT-PCR positive patients and nine non-COVID-19 pneumonia controls were admitted in this study. Blood samples were collected at hospital admission (T1) (Controls and COVID-19 patients) and 0-72 h before hospital discharge (T2, alive or dead) to analyze systemic cytokines and chemokines, lipopolysaccharide (LPS) concentrations and soluble CD14 (sCD14) levels. THP-1 human monocytic cell line was incubated with plasma from survivors and non-survivors COVID-19 patients and their phenotype, activation status, TLR4, and chemokine receptors were analyzed by flow cytometry. COVID-19 patients presented higher IL-6, IFN-γ, TNF-α, TGF-ß1, CCL2/MCP-1, CCL4/MIP-1ß, and CCL5/RANTES levels than controls. Moreover, LPS and sCD14 were higher at hospital admission in SARS-CoV-2-infected patients. Non-survivors COVID-19 patients had increased LPS levels concomitant with higher IL-6, TNF-α, CCL2/MCP-1, and CCL5/RANTES levels at T2. Increased expression of CD16 and CCR5 were identified in THP-1 cells incubated with the plasma of survivor patients obtained at T2. The incubation of THP-1 with T2 plasma of non-survivors COVID-19 leads to higher TLR4, CCR2, CCR5, CCR7, and CD69 expression. In conclusion, the coexistence of increased microbial translocation and hyperinflammation in patients with severe COVID-19 may lead to higher monocyte activation, which may be associated with worsening outcomes, such as death.

Differential effects of whole blood heat treatment on the ex vivo inflammatory profile of untrained and trained men.

This study evaluated the effects of heat stress on the ex vivo inflammatory profile in untrained and trained men. Whole blood samples from untrained (UT) and trained (TR) individuals were incubated for 2 h at 37 °C or 40 °C. The whole blood of a subsample of the participants (n = 5 in both TR and UT groups) were stimulated with lipopolysaccharide (LPS, 10 ng/mL) concomitant to heat treatment (37 °C versus 40 °C). Flow cytometry was used to assess the intracellular NF-κB activation in CD4+ T cells and CD14+ monocytes, the expression of Toll-Like Receptor-4 (TLR-4), the frequencies of CD4+CD25-CD39+ and CD4+CD25+CD39+ T cells and monocyte subsets (CD14+CD16-; CD14+CD16+; CD14-CD16+), the mitochondrial membrane potential (MMP) and the reactive oxygen species (ROS) production by lymphocytes and monocytes. The production of interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) by LPS-stimulated whole blood were also evaluated. Heat treatment (40 °C) increased the proportions of CD14+CD16- and CD14+CD16+ monocytes and the lymphocyte MMP in the UT group. The frequencies of CD14-CD16+ monocytes and the activation of NF-κB in CD14+ monocytes decreased in UT and TR groups after heat treatment, while a reduction in CD4+CD25-CD39+ T-cells was observed only in the UT group. Higher TLR-4 and NF-κB activation were found in LPS-stimulated monocytes of UT men concomitant with higher TNF-α production and diminished IL-10 production after heat treatment. TR individuals presented lower NF- κB activation in LPS-stimulated monocytes after heat treatment. Our data suggest that the training status of individuals may impact on the anti-inflammatory response of heat treatment.

Levels of cardiorespiratory fitness in men exerts strong impact on lymphocyte function after mitogen stimulation.

Relationship between lymphocyte function and cardiorespiratory fitness (CRF) is well-documented at rest; however, upon mitogen stimulation the proliferation and cytokine production alters, but knowledge is incipient about lymphocyte responses after mitogen stimulus according to CRF. So, the purpose of the present study was to analyze the lymphocyte function according to the physical fitness status of healthy young men. The study is divided in two experiments being the first analyzing the lymphocyte phenotypes profile and the inflammatory responses, according to CRF, in lymphocyte cell cultures treated for 48 h with concanavalin A (ConA). The second experiment analyzed the proliferation, reactive oxygen species production, viability, and mitochondrial polarization state in lymphocytes treated with ConA in different concentrations, considering the CRF levels. The results showed a difference in the percentage of total lymphocytes expression between groups (P = 0.011) observing a lower lymphocytes T expression in the group with high maximal oxygen consumption (V̇o2max) when compared with the moderate V̇o2max group. When treated with ConA, the lymphocytes of the low V̇o2max group released higher TNF-α concentration (P = 0.032), reflecting an elevated TNF-α/IL-10 ratio (P = 0.055), parallel with lower IL-6 production (P = 0.027), mainly when compared with the moderate V̇o2max group. In addition, there is a positive relationship between V̇o2max and IL-6 production (r = 0.507; P = 0.016), whereas the percentage of total lymphocytes (LyT%) shows a negative trend with V̇o2max (r = -0.497; P = 0.060). Also, individuals with lower V̇o2max showed reduced absolute and relative ROS production, lower cell proliferation, and higher mitochondrial membrane depolarization. In conclusion, cardiorespiratory fitness degree exerts a strong impact on lymphocyte function after mitogen stimulation.NEW & NOTEWORTHY The innovation of the research is to elucidate the impact of different physical fitness status on metabolism, cell proliferation, and lymphocyte activity and, consequently, on the specific inflammatory response against a mitogen.

DNA damage in mononuclear cells following maximal exercise in sedentary and physically active lean and obese men.

We evaluated the impact of maximal exercise on oxidative stress and DNA damage in peripheral blood mononuclear cells (PBMC) from sedentary and exercised lean and obese men. PBMC were collected before, immediately and 1-h after exercise and exposed to hydrogen peroxide (H2O2; 25 and 50 µM, 4 h). A leukocytosis was induced by maximal exercise immediately and 1-h after exercise in all groups. However, a lymphopenia was observed 1-h after exercise in the Sedentary obese group. In the control condition, low DNA damage index concomitant to increases in intracellular glutathione content (GSH) was identified immediately after exercise in all groups. However, higher DNA damage index and lipid peroxidation occurred 1-h after the bout in Sedentary and Exercised Obese groups. PBMC exposed to both H2O2 25 and 50 µM experienced higher DNA damage and lipid peroxidation index immediately after exercise in all groups. Both lipid peroxidation and DNA damage index remained higher in PBMC of Sedentary Lean, Sedentary Obese, and Exercised obese groups obtained 1-h after exercise in both H2O2 25 and 50 µM, with the highest values identified in PBMC from Sedentary Obese group. However, increases in GSH content were identified in treated PBMC from sedentary and exercised lean groups as well as exercised obese group 1-h after exercise. Habitual exercise confers increased resistance of PBMC to DNA damage induced by oxidative stress, reducing the detrimental effects of obesity.Keywords: Exercise, physical activity, DNA damage, obesity, mutagenesis, oxidative stress.

ß-Lapachone Increases Survival of Septic Mice by Regulating Inflammatory and Oxidative Response.

Sepsis is characterized by a dysregulated immune response to infection characterized by an early hyperinflammatory and oxidative response followed by a subsequent immunosuppression phase. Although there have been some advances in the treatment of sepsis, mortality rates remain high, urging for the search of new therapies. ß-Lapachone (ß-Lap) is a natural compound obtained from Tabebuia avellanedae Lorentz ex Griseb. with several pharmacological properties including bactericidal, anti-inflammatory, and antioxidant activity. Thus, the aim of this study was to evaluate the effects of ß-Lap in a mouse sepsis model. To this, we tested two therapeutic protocols in mice submitted to cecal ligation and puncture- (CLP-) induced sepsis. First, we found that in pretreated animals, ß-Lap reduced the systemic inflammatory response and improved bacterial clearance and mouse survival. Moreover, ß-Lap also decreased lipid peroxidation and increased the total antioxidant capacity in the serum and peritoneal cavity of septic animals. In the model of severe sepsis, the posttreatment with ß-Lap was able to increase the survival of animals and maintain the antioxidant defense function. In conclusion, the ß-Lap was able to increase the survival of septic animals by a mechanism involving immunomodulatory and antioxidant protective effects.

Immunoregulation induced by autologous serum collected after acute exercise in obese men: a randomized cross-over trial.

In this study, we evaluated the effects of autologous serum collected after two types of exercise on the in vitro inflammatory profile and T cell phenotype of resting peripheral blood mononuclear cells (PBMCs) in obese men. Serum samples and PBMCs were obtained from eight obese men who performed two exercise bouts-high intensity interval exercise (HIIE) and exhaustive exercise session to voluntary fatigue-in a randomized cross-over trial. Pre-exercise PBMCs were incubated with 50% autologous serum (collected before and after each exercise bout) for 4 h. In vitro experiments revealed that post-HIIE serum reduced the histone H4 acetylation status and NF-κB content of PBMCs and suppressed the production of both TNF-α and IL-6 by PBMCs, while increasing IL-10 production. Post-exhaustive exercise serum induced histone H4 hyperacetylation and mitochondrial depolarization in lymphocytes and increased TNF-α production. In vitro post-HIIE serum incubation resulted in an increase in the frequencies of CD4 + CTLA-4 + and CD4 + CD25+ T cells expressing CD39 and CD73. Post-exhaustive exercise serum decreased the frequency of CD4 + CD25 + CD73+ T cells but increased CD4 + CD25-CD39 + T cell frequency. Both post-exercise serums increased the proportions of CD4 + PD-1 + and CD8 + PD-1+ T cells. Blood serum factors released during exercise altered the immune response and T cell phenotype. The type of exercise impacted the immunomodulatory activity of the post-exercise serum on PBMCs.

New Insights about Regulatory T Cells Distribution and Function with Exercise: The Role of Immunometabolism.

A lack of physical activity is linked to the development of many chronic diseases through a chronic low-grade inflammation state. It is now well accepted that the immune system plays a central role in the development of several chronic diseases, including insulin resistance, type 2 diabetes, atherosclerosis, heart failure and certain types of cancer. Exercise elicits a strong anti-inflammatory response independently of weight loss and can be a useful non-pharmacologic strategy to counteract the low-grade inflammation. The CD4+CD25+CD127- FoxP3+ Regulatory T (Treg) cells are a unique subset of helper T-cells, which regulate immune response and establish self-tolerance through the secretion of immunoregulatory cytokines, such as IL-10 and TGF-ß, and the suppression of the function and activity of many immune effector cells (including monocytes/macrophages, dendritic cells, CD4+ and CD8+ T cells, and Natural Killers). The metabolic phenotype of Tregs are regulated by the transcription factor Foxp3, providing flexibility in fuel choice, but a preference for higher fatty acid oxidation. In this review, we focus on the mechanisms by which exercise - both acute and chronic - exerts its antiinflammatory effects through Treg cells mobilization. Furthermore, we discuss the implications of immunometabolic changes during exercise for the modulation of Treg phenotype and its immunosuppressive function. This narrative review focuses on the current knowledge regarding the role of Treg cells in the context of acute and chronic exercise using data from observational and experimental studies. Emerging evidence suggests that the immunomodulatory effects of exercise are mediated by the ability of exercise to adjust and improve Tregs number and function.

Blood flow restriction impairs the inflammatory adaptations of strength training in overweight men: a clinical randomized trial.

The aim of this study was to evaluate the impact of high-intensity strength training (ST) or low-intensity strength training with blood flow restriction (ST-BFR) on monocyte subsets, the expression of C-C chemokine receptor 5 (CCR5), and CD16 on monocytes, and tumor necrosis factor alpha (TNF-α) production of overweight men. Thirty overweight men were randomly assigned to conventional ST or ST-BFR. Both groups performed exercises of knee extension and biceps curl with equal volume (3 sessions/week) over 8 weeks, and the peripheral frequency of monocytes (CD14+CD16-, classical monocytes; CD14+CD16+, intermediate monocytes; CD14-CD16+, nonclassical monocytes), the mean fluorescence intensity (MFI) of CCR5 and CD16 on CD14+ monocytes; and the production of TNF-α by lipopolysaccharide (LPS)-stimulated cells were quantified. Eight weeks of ST increased the frequency of CD14+CD16- monocytes (p = 0.04) and reduced the percentage of CD14-CD16+ (p = 0.02) and the production of TNF-α by LPS-stimulated cells (p = 0.03). The MFI of CD16 on CD14+ monocytes decreased after the ST intervention (p = 0.02). No difference in monocyte subsets, CCR5 or CD16 expression, and TNF-α production were identified after ST-BFR intervention (p > 0.05). The adoption of ST promotes anti-inflammatory effects on monocyte subsets of overweight men, but this effect was lost when BFR was adopted. Novelty High-intensity strength training reduces the production of TNF-α and the peripheral frequency of CD16+ monocytes in overweight men. Blood flow restriction method blunts the strength training adaptations on monocyte subsets and pro-inflammatory TNF-α production in overweight men.

Cardiorespiratory fitness modulates the proportions of monocytes and T helper subsets in lean and obese men.

This study investigated the peripheral frequency of monocytes, CD4 + T cell subsets and the systemic levels of cytokines in lean and obese men with different levels of cardiorespiratory fitness (CRF). Mononuclear cells were obtained from 45 lean and 45 obese men who were assigned into six groups according to their body mass index and CRF (low, moderate, or high VO2Peak ) to analyze the frequency of monocyte subsets and subpopulations of CD4 + T cells (Treg cells, CD4 + CD25high CD127low ; mTeff, CD4 + CD25-CD39+; mTreg, CD4 + CD25+CD39+). The systemic levels of interleukin (IL)-6, IL-10, IL-17a, IL-33, leptin, and tumor necrosis factor-alpha (TNF-α) were also evaluated. Seven sedentary obese men performed one week of high-intensity interval training (HIIT, 3 sessions/week), and blood samples were collected before and 24 hours after the last session for phenotypic analysis of T cells and monocytes. Obese individuals presented an inflammatory profile characterized by lower frequencies of Treg and mTreg cells and higher proportions of proinflammatory monocytes. However, higher CRF status increased the frequencies of Treg cells and mTreg cells and decreased the percentage of CD4 + mTeff cells and intermediate and non-classical monocytes in the peripheral blood from lean and obese men. Systemic lower levels of proinflammatory (IL-6 and TNF-) cytokines and higher concentrations of IL-10 and IL-33 were observed in moderate and higher CRF in all subjects. HIIT increased the proportions of circulating mTreg and Treg cells in sedentary obese individuals. The immunoregulatory role of CRF contributes to the maintenance of low levels of inflammatory mediators.

Physical fitness modulates the expression of CD39 and CD73 on CD4+ CD25- and CD4+ CD25+ T cells following high intensity interval exercise.

AIM: To investigate the impact of physical fitness on the mobilization of CD4+ CD25 - CD39 + and CD4 + CD25 + CD39 + T cells in response to acute exercise. METHODS: Fifteen high physical fitness (25.3 ± 1.4 years) and 15 low physical fitness (26.1 ± 1.9 years) men performed a single bout of high-intensity interval exercise (HIIE, 10 bouts of 60 seconds at 85% HRmax intercepted by 75 seconds of recovery at 50% HRmax). Blood lymphocytes were isolated before, immediately after and 1 hour after exercise for assessment of cell surface expression of CD25, CD39, and CD73 on CD4+ T cells. Effector memory T cells (mTeff) were identified by CD4 + CD25 - CD39 + coexpression, and memory regulatory T cells (mTReg) were defined as CD4 + CD25 + CD39 + T cells. RESULTS: Exercise increased CD4+ and CD4 + CD25 + T cell frequencies immediately after followed by a decrease bellow to baseline values at 1 hour after the bout in both low and high physical fitness groups. At baseline, the proportions of mTeff were higher, while mTreg were lower in low physical fitness individuals. The frequency of mTreg increased immediately after HIIE in both groups, and remained higher 1 hour after the bout. However, high physical fitness individuals presented higher mTreg frequency in all periods evaluated. A significantly mobilization of mTeff cells was identified in both groups immediately after HIIE. High physical fitness individuals displayed a decrease in mTeff cells bellow to baseline, while the frequency of mTeff remained higher in low physical fitness group 1 hour after the bout. The peripheral frequency of CD4 + CD25 + CD73 + T cells increased in a similar way immediately after the bout in both groups, returning to the baseline values 1 hour after exercise. No differences in CD4 + CD25 - CD73 + T cells were observed after HIIE in both groups. CONCLUSION: Our results highlight the impact of physical activity status in the redistribution of CD4+ T cells expressing ectonucleotidases in response to HIIE.

Acute fish oil supplementation modulates the inflammatory response after strenuous exercise in obese men: A cross-over study.

AIM: To evaluate the effects of acute fish oil supplementation (FOS) in DNA damage, lymphocyte phenotype and cytokines production after strenuous exercise in obese individuals. METHODS: Sixteen sedentary obese (BMI >30.0 to <35.0 kg/m²) men performed two sessions of exhaustive exercise and consumed 2000 mg of either placebo or fish oil one hour before the exercise session; trials were separated by 14 days. Peripheral blood mononuclear cells were collected pre, immediately after and 1 h after both exercise sessions and stimulated in vitro with 2% phytohemagglutinin for cytokines secretion (IL-6, IL-8, TNF-α). Analysis of DNA damage index on total lymphocytes and the peripheral frequency of T helper CD4+ cells, T cytotoxic CD8+ cells, and CD19+ B cells were also performed. RESULTS: FOS prevented the increase in serum cortisol levels and the production of TNF-α and IL-8 after strenuous exercise. The DNA damage index decreased 1 h after exercise in FOS trial. Moreover, a lymphocytosis, i.e. increases in the frequency of CD4+ and CD8+ T cells was observed immediately after exercise bout in both trials. Moreover, FOS prevented the decrease in CD8+ T cells below to baseline value 1 h after strenuous exercise. CONCLUSION: Acute supplementation with fish oil attenuates the proinflammatory cytokine response and diminished the DNA damage after strenuous exercise in obese individuals, suggesting a possible protective effect against the exacerbation of systemic damage induced by exhaustive exercise in obese individuals.

Nanoparticle vaccines against viral infections.

Despite numerous efforts, we still do not have prophylactic vaccines for many clinically relevant viruses, such as HIV, hepatitis C virus, Zika virus, and respiratory syncytial virus. Several factors have contributed to the current lack of effective vaccines, including the high rate of viral mutation, low immunogenicity of recombinant viral antigens, instability of viral antigenic proteins administered in vivo, sophisticated mechanisms of viral immune evasion, and inefficient induction of mucosal immunity by vaccine models studied to date. Some of these obstacles could be partially overcome by the use of vaccine adjuvants. Nanoparticles have been intensively investigated as vaccine adjuvants because they possess chemical and structural properties that improve immunogenicity. The use of nanotechnology in the construction of immunization systems has developed into the field of viral nanovaccinology. The purpose of this paper is to review and correlate recent discoveries concerning nanoparticles and specific properties that contribute to the immunogenicity of viral nanoparticle vaccines, bio-nano interaction, design of nanoparticle vaccines for clinically relevant viruses, and future prospects for viral nanoparticle vaccination.

Acute exercise during hemodialysis prevents the decrease in natural killer cells in patients with chronic kidney disease: a pilot study.

PURPOSE: To evaluate the acute response of natural killer (NK) cell subsets of chronic kidney disease patients submitted to intradialytic exercise in a randomized crossover study. METHODS: Nine patients were submitted to a single bout of 20-min intradialytic exercise and a control hemodialysis (HD) session with an interval of 7 days between them. Peripheral blood sample was collected at baseline, during HD and immediately after HD in each trial to evaluate the peripheral frequency of NK cells and their subsets (CD3-CD56bright and CD3-CD56dim), systemic cortisol concentrations, C-reactive protein (CRP), creatine kinase activity (CK), and urea and creatinine levels. RESULTS: HD therapy induced a significant decrease in NK cells frequency (p = 0.039), NK CD3-CD56bright cells (p = 0.04), and CD3-CD56dim cells (p = 0.036). On the other hand, no significant alterations were observed in NK cells and NK subsets during and after intradialytic exercise trial (p > 0.05). Neither trial altered CRP levels or serum CK activity during and after HD therapy (p > 0.05). However, HD therapy increased cortisol concentrations after HD therapy (p = 0.034). CONCLUSIONS: This study suggests the potential role of intradialytic exercise to prevent the decrease in peripheral frequency of NK cell subsets during HD therapy. Moreover, moderate intensity intradialytic exercise did not exacerbate the systemic inflammation or induce muscle damage during HD therapy.

Acute Strenuous Exercise Induces an Imbalance on Histone H4 Acetylation/Histone Deacetylase 2 and Increases the Proinflammatory Profile of PBMC of Obese Individuals.

This study evaluated the response of global histone H4 acetylation (H4ac), histone deacetylase 2 (HDAC2) activity, as well as the production of proinflammatory cytokines and monocyte phenotypes of lean and obese males after exercise. Ten lean and ten obese sedentary men were submitted to one session of strenuous exercise, and peripheral blood mononuclear cells (PBMC) were stimulated in vitro with lipopolysaccharide (LPS). Global H4ac levels, HDAC2 activity in PBMC, and IL-6, IL-8, and TNF-α production were analyzed. Monocyte phenotype was determined in accordance with the expression of CD14 and CD16. At rest, obese individuals presented higher frequency of proinflammatory CD14+CD16+ monocytes. LPS induced a significant augment in global H4ac and in the production of IL-6, IL-8, and TNF-α mainly in obese individuals. After exercise, the increased production of IL-8 and TNF-α and peripheral frequency of CD14+CD16+ were observed in both groups. In addition, exercise also induced a significant hyperacetylation of histone H4 and decreased HDAC2 activity in both nonstimulated and LPS-stimulated PBMC of obese individuals. Our data indicate that the obesity impacts on H4ac levels and that strenuous exercise leads to an enhanced chronic low-grade inflammation profile in obesity via an imbalance on H4ac/HDAC2.

High intensity interval exercise decreases IL-8 and enhances the immunomodulatory cytokine interleukin-10 in lean and overweight-obese individuals.

PURPOSE: To compare the effects of two interval exercises with different intensities on acute inflammatory response in lean and overweight-obese subjects. METHODS: Ten lean (BMI<24.9kg/m(2)) and 12 overweight-obese (BMI 25 to <34.9kg/m(2)) males performed two conditions in randomly assigned: (1) high intensity interval exercise (HIIE) 10×60s (85-90%PMax)/75s (50%PMax); (2) moderate intensity interval exercise (MIIE) 10×60s (70-75%PMax)/60s (50%PMax), with blood collections at pre, immediately and 30min post each exercise bouts to evaluate total and differential leukocyte counts, serum creatine kinase (CK), lactate dehydrogenase (LDH) and systemic levels of IL-1ra, IL-6, IL-8, IL-10, IL-17a and CCL2. RESULTS: In lean group, HIIE induced a significant increase in total leukocytes and monocyte, while MIIE session did not change the number of leukocytes. Overweight-obese group presented similar increase in leukocytes, monocytes and lymphocytes in both HIIE and MIIE sessions. At baseline, overweight-obese group showed high levels of CK, IL-8, IL-6 and CCL2 and lower concentrations of IL-10 compared to lean group. The MIIE did not alter the cytokine concentrations in both groups, independently of the time analysis. The HIIE induced significant decrease in IL-8 levels 30min post session in both the groups, and a progressive elevation in IL-10 levels immediately and 30min post in lean and overweight-obese. Regarding IL-6, overweight-obese subjects presented progressive increase either immediately and 30min after HIIE, while lean individuals presented significant increase only 30min after exercise. CONCLUSIONS: The acute inflammatory response to interval exercise is intensity-dependent. Although obesity influences the basal concentrations of several cytokines, only HIIE induced important alterations in IL-8 and IL-10 levels, which may have important implications in the control of chronic low-grade inflammation in obesity.