Adiposity induces lethal cytokine storm after systemic administration of stimulatory immunotherapy regimens in aged mice

Potential roles of sex-linked differences in obesity and cancer immunotherapy: revisiting the obesity paradox

Obesity, a condition of excess adiposity usually defined by a BMI > 30, can have profound effects on both metabolism and immunity, connecting the condition with a broad range of diseases, including cancer and negative outcomes. Obesity and cancer have been associated with increased incidence, progression, and poorer outcomes of multiple cancer types in part due to the pro-inflammatory state that arises. Surprisingly, obesity has also recently been demonstrated in both preclinical models and clinical outcomes to be associated with improved response to immune checkpoint inhibition (ICI). These observations have laid the foundation for what has been termed the "obesity paradox". The mechanisms underlying these augmented immunotherapy responses are still unclear given the pleiotropic effects obesity exerts on cells and tissues. Other important variables such as age and sex are being examined as further affecting the obesity effect. Sex-linked factors exert significant influences on obesity biology, metabolism as well as differential effects of different immune cell-types. Age can be another confounding factor contributing to the effects on both sex-linked changes, immune status, and obesity. This review aims to revisit the current body of literature describing the immune and metabolic changes mediated by obesity, the role of obesity on cancer immunotherapy, and to highlight questions on how sex-linked differences may influence obesity and immunotherapy outcome.

Impact of the immune profiles of hypertensive patients with and without obesity on COVID-19 severity

BACKGROUND

Comorbidities such as obesity, hypertension, and diabetes are associated with COVID-19 development and severity, probably due to immune dysregulation; however, the mechanisms underlying these associations are not clear. The immune signatures of hypertensive patients with obesity with COVID-19 may provide new insight into the mechanisms of immune dysregulation and progression to severe disease in these patients.

METHODS

Hypertensive patients were selected prospectively from a multicenter registry of adults hospitalized with COVID-19 and stratified according to obesity (BMI ≥ 30 kg/m²). Clinical data including baseline characteristics, complications, treatment, and 46 immune markers were compared between groups. Logistic regression was performed to identify variables associated with the risk of COVID-19 progression in each group.

RESULTS

The sample comprised 213 patients (89 with and 124 without obesity). The clinical profiles of patients with and without obesity differed, suggesting potential interactions with COVID-19 severity. Relative to patients without obesity, patients with obesity were younger and fewer had cardiac disease and myocardial injury. Patients with obesity had higher EGF, GCSF, GMCSF, interleukin (IL)-1ra, IL-5, IL-7, IL-8, IL-15, IL-1β, MCP 1, and VEGF levels, total lymphocyte counts, and CD8+ CD38+ mean fluorescence intensity (MFI), and lower NK-NKG2A MFI and percentage of CD8+ CD38+ T cells. Significant correlations between cytokine and immune cell expression were observed in both groups. Five variables best predicted progression to severe COVID-19 in patients with obesity: diabetes, the EGF, IL-10, and IL-13 levels, and the percentage of CD8+ HLA-DR+ CD38+ cells. Three variables were predictive for patients without obesity: myocardial injury and the percentages of B lymphocytes and HLA-DR+ CD38+ cells.

CONCLUSION

Our findings suggest that clinical and immune variables and obesity interact synergistically to increase the COVID-19 progression risk. The immune signatures of hypertensive patients with and without obesity severe COVID-19 highlight differences in immune dysregulation mechanisms, with potential therapeutic applications.

A comprehensive review on immune checkpoint inhibitors induced cardiotoxicity characteristics and associated factors

Newly approved cancer drugs called ICIs have shown remarkable success in improving patient survival rates, but they also have the potential for inflammatory and immune-related side effects, including those affecting the cardiovascular system. Research has been conducted to understand the development of these toxicities and identify risk factors. This review focuses on the characteristics of ICI-induced cardiotoxicity and discusses the reported risk factors. It is important for cardio-oncologists to understand the basic concepts of these drugs to better understand how cardiotoxicities occur. It might be hard to find reports, where all patients treated with ICIs had developed cardiac toxicity, because there could be other existing and variable factors that influence the likelihood or risk of developing cardiotoxicity during treatment. Various clinical parameters have been explored as potential risk factors, and further investigation is needed through large-scale studies.

Visceral fat and cardiometabolic future in children and adolescents: a critical update

Cardiovascular disease (CVD) is a process whose pathogenetic mechanisms start very early in life. Recently, the importance of visceral adipose tissue (VAT) has been highlighted in the development of CVD. VAT does not always depend on body mass index (BMI) and has been implicated in unfavorable metabolic activity and cardiovascular adverse events. Abnormally high deposition of VAT is associated with metabolic syndrome, obesity-associated phenotype, and cardiometabolic risk factors. Although the importance of visceral fat has not been studied broadly or extensively in long-term studies in children and adolescents, it appears that it does not have the same behavior as in adults, it is related to the appearance of cardiac risk factors. In adolescents, it plays a role in the pathogenesis of CVD that occur later in adulthood. Excess body weight and adiposity may lead to the development of early myocardial and pathological coronary changes in childhood. The purpose of this review is to summarize the risk factors, the clinical significance, and the prognostic role of visceral obesity in children and adolescents. In addition, extensive reference is made to the most commonly used techniques for the evaluation of VAT in clinical settings. IMPACT: Visceral obesity, plays an important role in cardiovascular health from very early in an individual's life. Visceral adipose tissue (VAT) distribution is not entirely related to body mass index (BMI) and provides additional prognostic information. There is a need to pay more attention to the assessment of VAT in young people, to develop methods that would go beyond the measurement of only BMI in clinical practice and to identify individuals with excess visceral adiposity and perhaps to monitor its changes.

Multifaceted effects of obesity on cancer immunotherapies: Bridging preclinical models and clinical data

Obesity, defined by excessive body fat, is a highly complex condition affecting numerous physiological processes, such as metabolism, proliferation, and cellular homeostasis. These multifaceted effects impact cells and tissues throughout the host, including immune cells as well as cancer biology. Because of the multifaceted nature of obesity, common parameters used to define it (such as body mass index in humans) can be problematic, and more nuanced methods are needed to characterize the pleiotropic metabolic effects of obesity. Obesity is well-accepted as an overall negative prognostic factor for cancer incidence, progression, and outcome. This is in part due to the meta-inflammatory and immunosuppressive effects of obesity. Immunotherapy is increasingly used in cancer therapy, and there are many different types of immunotherapy approaches. The effects of obesity on immunotherapy have only recently been studied with the demonstration of an "obesity paradox", in which some immune therapies have been demonstrated to result in greater efficacy in obese subjects despite the direct adverse effects of obesity and excess body fat acting on the cancer itself. The multifactorial characteristics that influence the effects of obesity (age, sex, lean muscle mass, underlying metabolic conditions and drugs) further confound interpretation of clinical data and necessitate the use of more relevant preclinical models mirroring these variables in the human scenario. Such models will allow for more nuanced mechanistic assessment of how obesity can impact, both positively and negatively, cancer biology, host metabolism, immune regulation, and how these intersecting processes impact the delivery and outcome of cancer immunotherapy.

Stocking the toolbox-Using preclinical models to understand the development and treatment of immune checkpoint inhibitor-induced immune-related adverse events

Cancer patients treated with immune checkpoint inhibitors (ICIs) are susceptible to a broad and variable array of immune-related adverse events (irAEs). With increasing clinical use of ICIs, defining the mechanism for irAE development is more critical than ever. However, it currently remains challenging to predict when these irAEs occur and which organ may be affected, and for many of the more severe irAEs, inaccessibility to the tissue site hampers mechanistic insight. This lack of understanding of irAE development in the clinical setting emphasizes the need for greater use of preclinical models that allow for improved prediction of biomarkers for ICI-initiated irAEs or that validate treatment options that inhibit irAEs without hampering the anti-tumor immune response. Here, we discuss the utility of preclinical models, ranging from exploring databases to in vivo animal models, focusing on where they are most useful and where they could be improved.

Bariatric surgery in the prevention of obesity-associated cancers: mechanistic implications

Obesity is associated with an increased risk of at least 13 different cancers, as well as worse cancer outcomes and increased cancer mortality. As rates continue to rise both in the United States and worldwide, obesity is poised to become the leading lifestyle-related risk factor for cancer. Currently, the most effective treatment for patients with severe obesity is bariatric surgery. Multiple cohort studies have demonstrated a consistent >30% decreased risk of cancer incidence in women, but not men, following bariatric surgery. However, the physiologic mechanisms driving obesity-associated cancer and the cancer-protective effect of bariatric surgery are not clearly defined. In this review, we highlight emerging concepts in the mechanistic understanding of obesity-associated cancer. Evidence from both human studies and preclinical animal models suggest that obesity drives carcinogenesis through dysregulation of systemic metabolism, immune dysfunction, and an altered gut microbiome. Additionally, we present related findings to suggest that bariatric surgery may disrupt and even reverse many of these mechanisms. Finally, we discuss the use of preclinical bariatric surgery animal models in the study of cancer biology. The prevention of cancer is emerging as an important indication for bariatric surgery. Elucidating the mechanisms through which bariatric surgery limits carcinogenesis is critical to developing a variety of interventions that intercept obesity-driven cancer.

Goliath induces inflammation in obese mice by linking fatty acid β-oxidation to glycolysis

Obesity is associated with metabolic disorders and chronic inflammation. However, the obesity-associated metabolic contribution to inflammatory induction remains elusive. Here, we show that, compared with lean mice, CD4+ T cells from obese mice exhibit elevated basal levels of fatty acid β-oxidation (FAO), which promote T cell glycolysis and thus hyperactivation, leading to enhanced induction of inflammation. Mechanistically, the FAO rate-limiting enzyme carnitine palmitoyltransferase 1a (Cpt1a) stabilizes the mitochondrial E3 ubiquitin ligase Goliath, which mediates deubiquitination of calcineurin and thus enhances activation of NF-AT signaling, thereby promoting glycolysis and hyperactivation of CD4+ T cells in obesity. We also report the specific GOLIATH inhibitor DC-Gonib32, which blocks this FAO-glycolysis metabolic axis in CD4+ T cells of obese mice and reduces the induction of inflammation. Overall, these findings establish a role of a Goliath-bridged FAO-glycolysis axis in mediating CD4+ T cell hyperactivation and thus inflammation in obese mice.

Diet Influences Immunotherapy Outcomes in Cancer Patients: A Literature Review

The outbreak of immunotherapy has revolutionized cancer treatment. Despite the results confirming the effectiveness of immunotherapy, some studies have reported poor responsiveness to this therapeutic approach. The effectiveness of immunotherapy is dependent on numerous factors related to patients' lifestyles and health status. Diet, as an essential component of lifestyle, plays a major role in determining immunotherapy outcomes. It can significantly influence the body, gut microbiome composition, and metabolism, both in general and in tumor microenvironment. Consuming certain diets has resulted in either improved or worsened outcomes in patients receiving immunotherapy. For example, several recent studies have associated ketogenic, plant-based, and microbiome-favoring diets with promising outcomes. Moreover, obesity and dietary deprivation have impacted immunotherapy responsiveness, yet the studies are inconsistent in this context. This narrative review aims to integrate the results from many articles that have studied the contribution of diet to immunotherapy. We will start by introducing the multiple effects of dietary status on cancer progression and treatment. Then we will proceed to discuss various regimens known to affect immunotherapy outcomes, including ketogenic, high-fiber, and obesity-inducing diets and regimens that either contain or lack specific nutrients. Finally, we will elaborate on how composition of the gut microbiome may influence immunotherapy.

Leukocyte metabolism in obese type 2 diabetic individuals associated with COVID-19 severity

Recent studies show that the metabolic characteristics of different leukocytes, such as, lymphocytes, neutrophils, and macrophages, undergo changes both in the face of infection with SARS-CoV-2 and in obesity and type 2 diabetes mellitus (DM2) condition. Thus, the objective of this review is to establish a correlation between the metabolic changes caused in leukocytes in DM2 and obesity that may favor a worse prognosis during SARS-Cov-2 infection. Chronic inflammation and hyperglycemia, specific and usual characteristics of obesity and DM2, contributes for the SARS-CoV-2 replication and metabolic disturbances in different leukocytes, favoring the proinflammatory response of these cells. Thus, obesity and DM2 are important risk factors for pro-inflammatory response and metabolic dysregulation that can favor the occurrence of the cytokine storm, implicated in the severity and high mortality risk of the COVID-19 in these patients.

Reprogramming the tumor microenvironment to improve the efficacy of cancer immunotherapies

The immunotherapeutic approaches based on checkpoint inhibitors, tumor vaccination, immune cell-based therapy, and cytokines were developed to engage the patient's immune system against cancer and better survival of them. While potent, however, preclinical and clinical data have identified that abnormalities in the tumor microenvironment (TME) can affect the efficacy of immunotherapies in some cancers. It is therefore imperative to develop new therapeutic interventions that will enable to overcome tumor-supportive TME and restrain anti-tumor immunity in patients that acquire resistance to current immunotherapies. Therefore, recognition of the essential nature of the tolerogenic TME may lead to a shift from the immune-suppressive TME to an immune-stimulating phenotype. Here, we review the composition of the TME and its effect on tumor immunoediting and then present how targeted monotherapy or combination therapies can be employed for reprogramming educated TME to improve current immunotherapies outcomes or elucidate potential therapeutic targets.

Translating MSC Therapy in the Age of Obesity

Mesenchymal stromal cell (MSC) therapy has seen increased attention as a possible option to treat a number of inflammatory conditions including COVID-19 acute respiratory distress syndrome (ARDS). As rates of obesity and metabolic disease continue to rise worldwide, increasing proportions of patients treated with MSC therapy will be living with obesity. The obese environment poses critical challenges for immunomodulatory therapies that should be accounted for during development and testing of MSCs. In this review, we look to cancer immunotherapy as a model for the challenges MSCs may face in obese environments. We then outline current evidence that obesity alters MSC immunomodulatory function, drastically modifies the host immune system, and therefore reshapes interactions between MSCs and immune cells. Finally, we argue that obese environments may alter essential features of allogeneic MSCs and offer potential strategies for licensing of MSCs to enhance their efficacy in the obese microenvironment. Our aim is to combine insights from basic research in MSC biology and clinical trials to inform new strategies to ensure MSC therapy is effective for a broad range of patients.

Association between Antibiotic Exposure and Systemic Immune Parameters in Cancer Patients Receiving Checkpoint Inhibitor Therapy

Antibiotic administration is associated with worse clinical outcomes and changes to the gut microbiome in cancer patients receiving immune checkpoint inhibitors (ICI). However, the effects of antibiotics on systemic immune function are unknown. We, therefore, evaluated antibiotic exposure, therapeutic responses, and multiplex panels of 40 serum cytokines and 124 antibodies at baseline and six weeks after ICI initiation, with p < 0.05 and false discovery rate (FDR) < 0.2 considered significant. A total of 251 patients were included, of whom the 135 (54%) who received antibiotics had lower response rates and shorter survival. Patients who received antibiotics prior to ICI initiation had modestly but significantly lower baseline levels of nucleolin, MDA5, c-reactive protein, and liver cytosol antigen type 1 (LC1) antibodies, as well as higher levels of heparin sulfate and Matrigel antibodies. After ICI initiation, antibiotic-treated patients had significantly lower levels of MDA5, CENP.B, and nucleolin antibodies. Although there were no clear differences in cytokines in the overall cohort, in the lung cancer subset (53% of the study population), we observed differences in IFN-γ, IL-8, and macrophage inflammatory proteins. In ICI-treated patients, antibiotic exposure is associated with changes in certain antibodies and cytokines. Understanding the relationship between these factors may improve the clinical management of patients receiving ICI.

Bispecific antibodies increase the therapeutic window of CD40 agonists through selective dendritic cell targeting

Therapeutic use of agonistic anti-CD40 antibodies is a potentially powerful approach for activation of the immune response to eradicate tumors. However, the translation of this approach to clinical practice has been substantially restricted due to the severe dose-limiting toxicities observed in multiple clinical trials. Here, we demonstrate that conventional type 1 dendritic cells are essential for triggering antitumor immunity but not the toxicity of CD40 agonists, while macrophages, platelets and monocytes lead to toxic events. Therefore, we designed bispecific antibodies that target CD40 activation preferentially to dendritic cells, by coupling the CD40 agonist arm with CD11c-, DEC-205- or CLEC9A-targeting arms. These bispecific reagents demonstrate a superior safety profile compared to their parental CD40 monospecific antibody while triggering potent antitumor activity. We suggest such cell-selective bispecific agonistic antibodies as a drug platform to bypass the dose-limiting toxicities of anti-CD40, and of additional types of agonistic antibodies used for cancer immunotherapy.

The ambiguous role of obesity in oncology by promoting cancer but boosting antitumor immunotherapy

Obesity is nowadays considered a pandemic which prevalence's has been steadily increasingly in western countries. It is a dynamic, complex, and multifactorial disease which propitiates the development of several metabolic and cardiovascular diseases, as well as cancer. Excessive adipose tissue has been causally related to cancer progression and is a preventable risk factor for overall and cancer-specific survival, associated with poor prognosis in cancer patients. The onset of obesity features a state of chronic low-grade inflammation and secretion of a diversity of adipocyte-derived molecules (adipokines, cytokines, hormones), responsible for altering the metabolic, inflammatory, and immune landscape. The crosstalk between adipocytes and tumor cells fuels the tumor microenvironment with pro-inflammatory factors, promoting tissue injury, mutagenesis, invasion, and metastasis. Although classically established as a risk factor for cancer and treatment toxicity, recent evidence suggests mild obesity is related to better outcomes, with obese cancer patients showing better responses to treatment when compared to lean cancer patients. This phenomenon is termed obesity paradox and has been reported in different types and stages of cancer. The mechanisms underlying this paradoxical relationship between obesity and cancer are still not fully described but point to systemic alterations in metabolic fitness and modulation of the tumor microenvironment by obesity-associated molecules. Obesity impacts the response to cancer treatments, such as chemotherapy and immunotherapy, and has been reported as having a positive association with immune checkpoint therapy. In this review, we discuss obesity's association to inflammation and cancer, also highlighting potential physiological and biological mechanisms underlying this association, hoping to clarify the existence and impact of obesity paradox in cancer development and treatment.

Novel evidence of obesity paradox in esophageal adenocarcinoma: perspective on genes that uncouple adiposity from dismal outcomes

Background: Obesity is a strong risk factor for esophageal adenocarcinoma (EAC). Nevertheless, not all the patients with EAC are obesity, and a substantial proportion of obesity patients don't suffer from poor prognoses. The mechanisms behind the “obesity paradox” that uncouple obesity from dismal outcomes in EAC are unclear. This study aimed to explore the “obesity-guarding” genes (OGG) profiles and their prognostic values in patients with EAC.

Methods: Gene expression data and clinical information of patients with EAC were downloaded from The Cancer Genome Atlas (TCGA) database. Enrichment analysis was used to explore the OGG functions and pathways. Cox regression analysis and nomogram model were performed to investigate the OGG prognostic values for overall survival (OS). In addition, relations between OGG and immune cells were assessed by the “CIBERSORT” algorithm and the Tumor IMmune Estimation Resource (TIMER) tool. Finally, the results were experimentally validated in real-world study.

Results: A total of 69 OGG were retrieved, and 17 significantly differentially expressed genes (SDEG) were identified between normal and EAC tissues. Enrichment analysis showed the OGG were enriched in the mitochondrion-related and various receptor pathways. Univariate Cox regression results showed that the MCM6, ATXN2 and CSK were significantly associated with OS (P=0.036, 0.039, 0.046, respectively). Multivariate Cox regression analysis showed MCM6 and CSK were independent prognostic genes for OS (P=0.025, 0.041, respectively). Nomogram demonstrated that the OGG had good predictive abilities for the 1-, 2-, and 3-year OS. Immunity analysis demonstrated that OGG were significantly associated with immune cells (P <0.05). In addition, clinical correlation analysis revealed that the OGG had significant relations with clinical parameters (P <0.05). The experiment results confirmed that the SDEG were significantly different between normal and EAC tissues (P <0.05).

Conclusions: We identified the OGG expression profiles that may uncouple obesity from poor survival in patients with EAC. They have prognostic values in predicting patients' OS, and may be exploited for prognostic biomarkers.

Mechanisms of cellular and humoral immunity through the lens of VLP-based vaccines

INTRODUCTION

Vaccination can be effective defense against many infectious agents and the corresponding diseases. Discoveries elucidating the mechanisms of the immune system have given hopes to developing vaccines against diseases recalcitrant to current treatment/prevention strategies. One such finding is the ability of immunogenic biological nanoparticles to powerfully boost the immunogenicity of poorer antigens conjugated to them with virus-like particle (VLP)-based vaccines as a key example. VLPs take advantage of the well-defined molecular structures associated with sub-unit vaccines and the immunostimulatory nature of conjugate vaccines.

AREAS COVERED

In this review, we will discuss how advances in understanding the immune system can inform VLP-based vaccine design and how VLP-based vaccines have uncovered underlying mechanisms in the immune system.

EXPERT OPINION

As our understanding of mechanisms underlying the immune system increases, that knowledge should inform our vaccine design. Testing of proof-of-concept vaccines in the lab should seek to elucidate the underlying mechanisms of immune responses. The integration of these approaches will allow for VLP-based vaccines to live up to their promise as a powerful plug-and-play platform for next generation vaccine development.

The role of obesity and bariatric surgery-induced weight loss in breast cancer

Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.

β-Hydroxy-β-Methylbutyrate Supplementation Promotes Antitumor Immunity in an Obesity Responsive Mouse Model of Pancreatic Ductal Adenocarcinoma

Simple Summary

Pancreatic cancer (PDAC) is a deadly disease, exacerbated by obesity, which lacks effective therapeutic interventions. Most PDAC has a limited response to immune- and chemotherapy. Treating PDAC is made additionally challenging by the rapid emergence of muscle wasting and cachexia, which predict poor response to several therapies. We have found that dietary supplementation with β-hydroxy-β-methylbutyrate promotes immunosurveillance in PDAC tumors and protects muscle. This dietary supplement has the potential to be an important adjuvant in PDAC therapy, opening the doors to immunotherapy response.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the United States, and effective therapies for PDAC are currently lacking. Moreover, PDAC is promoted and exacerbated by obesity, while cachexia and sarcopenia are exceptionally common comorbidities that predict both poor survival and treatment response. Managing PDAC with immunotherapies has thus far proven ineffective, partly due to the metabolically hostile tumor microenvironment. β-hydroxy-β-methylbutyrate (HMB), a metabolite of leucine commonly used as a dietary supplement to boost muscle growth and immune function, may be an attractive candidate to augment PDAC therapy. We therefore sought to test the hypothesis that HMB would enhance antitumor immunity while protecting mouse muscle mass. Control and diet-induced obese C57BL/6 male mice bearing subcutaneously injected Panc02 tumors were supplemented with 1% HMB and treated with or without 50 mg/kg gemcitabine (n = 15/group). HMB was associated with reduced muscle inflammation and increased muscle fiber size. HMB also reduced tumor growth and promoted antitumor immunity in obese, but not lean, mice, independent of the gemcitabine treatment. Separately, in lean tumor-bearing mice, HMB supplementation promoted an anti-PD1 immunotherapy response (n = 15/group). Digital cytometry implicated the decreased abundance of M2-like macrophages in PDAC tumors, an effect that was enhanced by anti-PD1 immunotherapy. We confirmed that HMB augments M1-like macrophage (antitumor) polarization. These preclinical findings suggest that HMB has muscle-sparing and antitumor activities against PDAC in the context of obesity, and that it may sensitize otherwise nonresponsive PDAC to immunotherapy.

Increased efficacy of dual proinflammatory cytokine blockade on acute GVHD while maintaining GVT effects

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a potential curative option for treating a variety of hematologic diseases, but acute and chronic graft-versus-host disease (GVHD) remain major barriers limiting efficacy. Acute gut GVHD occurs with marked increases in proinflammatory cytokines (including TNF and IL-6), which we recently demonstrated was exacerbated in obesity resulting in severe gastrointestinal pathology. Given the pleiotropic and overlapping effects of these 2 cytokines, we assessed the impact of dual TNF and IL-6R blockade on GVHD as well as graft-versus tumor (GVT) effects in different mouse GVHD models. Early administration of combined blockade resulted in greater protection and survival from acute gut GVHD compared with single blockade regimens and even development of later chronic skin GVHD. Importantly, double cytokine blockade preserved GVT effects reinforcing that GVT and GVHD can be delineated and may result in greater efficacy in allo-HSCT.

Help or hindrance: The obesity paradox in cancer treatment response

Obesity is a rising epidemic, the influence of which on cancer development, progression as well as its impact on current standard of care cancer treatments is profound with many facets. Obesity is emerging as a modulating factor in many cancer therapies, such as chemotherapy, radiotherapy, immunotherapy and combination therapies. It has been reported to diminish the efficacy of some treatments but has also been alluded to being protective in terms of reduced treatment toxicities, thus the evolution of the obesity paradox. The obese tumour microenvironment influences treatment response through modulation of a series of aspects, including altered adipocyte secretome, angiogenesis, hypoxia, fibrosis, free fatty acid uptake as well as a modulated immune landscape. However, the influence of these underlying mechanisms on cancer treatment response and the biological action of adipose tissue is still largely unknown. Elucidation of these facets may lead to the enhanced efficacy of current treatment options or the identification of novel methods to combat cancer in the obese tumour microenvironment.

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.

Mechanisms by Which Obesity Promotes Acute Graft-Versus-Host Disease in Mice

The efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by the occurrence of acute and chronic graft-versus-host disease (GVHD). We have recently demonstrated that obesity results in exacerbated acute gastrointestinal GVHD in both mouse models and clinical outcomes due to increased pro-inflammatory cytokine responses and microbiota alterations. We therefore wanted to delineate the role of the various parameters in obesity, adiposity, effects of high-fat (HF) diet, and the role of microbiome on GVHD pathogenesis, by taking advantage of a mouse strain resistant to diet-induced obesity (DIO). Female BALB/c mice are resistant to DIO phenotype with approximately 50% becoming DIO under HF diets. The DIO-susceptible recipients rapidly succumb to acute gut GVHD, whereas the DIO-resistant recipient littermates, which do not become obese, are partially protected from GVHD, indicating that being on HF diet alone contributes to but is not the primary driver of GVHD. Microbiome assessment revealed restricted diversity in both cohorts of mice, but coprophagy normalizes the microbiota in mice housed together. We then individually housed DIO-resistant, DIO-susceptible, and lean control mice. Notably, each of the individually housed groups demonstrates marked restricted diversity that has been shown to occur from the stress of single housing. Despite the restricted microbiome diversity, the GVHD pathogenesis profile remains consistent in the group-housed mice, with the lean control single-housed mice exhibiting no acute GVHD and DIO-resistant recipients showing again partial protection. These results demonstrate that the deleterious effects of obesity on acute gut GVHD are critically dependent on adiposity with the HF diet also playing a lesser role, and the microbiome alterations with obesity instead appear to fuel ongoing acute GVHD processes.

COVID-19 and Obesity: Role of Ectopic Visceral and Epicardial Adipose Tissues in Myocardial Injury

In March 2020, the WHO declared coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a global pandemic. Obesity was soon identified as a risk factor for poor prognosis, with an increased risk of intensive care admissions and mechanical ventilation, but also of adverse cardiovascular events. Obesity is associated with adipose tissue, chronic low-grade inflammation, and immune dysregulation with hypertrophy and hyperplasia of adipocytes and overexpression of pro-inflammatory cytokines. However, to implement appropriate therapeutic strategies, exact mechanisms must be clarified. The role of white visceral adipose tissue, increased in individuals with obesity, seems important, as a viral reservoir for SARS-CoV-2 via angiotensin-converting enzyme 2 (ACE2) receptors. After infection of host cells, the activation of pro-inflammatory cytokines creates a setting conducive to the "cytokine storm" and macrophage activation syndrome associated with progression to acute respiratory distress syndrome. In obesity, systemic viral spread, entry, and prolonged viral shedding in already inflamed adipose tissue may spur immune responses and subsequent amplification of a cytokine cascade, causing worse outcomes. More precisely, visceral adipose tissue, more than subcutaneous fat, could predict intensive care admission; and lower density of epicardial adipose tissue (EAT) could be associated with worse outcome. EAT, an ectopic adipose tissue that surrounds the myocardium, could fuel COVID-19-induced cardiac injury and myocarditis, and extensive pneumopathy, by strong expression of inflammatory mediators that could diffuse paracrinally through the vascular wall. The purpose of this review is to ascertain what mechanisms may be involved in unfavorable prognosis among COVID-19 patients with obesity, especially cardiovascular events, emphasizing the harmful role of excess ectopic adipose tissue, particularly EAT.

Current Landscape: The Mechanism and Therapeutic Impact of Obesity for Breast Cancer

Obesity is defined as a chronic disease induced by an imbalance of energy homeostasis. Obesity is a widespread health problem with increasing prevalence worldwide. Breast cancer (BC) has already been the most common cancer and one of the leading causes of cancer death in women worldwide. Nowadays, the impact of the rising prevalence of obesity has been recognized as a nonnegligible issue for BC development, outcome, and management. Adipokines, insulin and insulin-like growth factor, sex hormone and the chronic inflammation state play critical roles in the vicious crosstalk between obesity and BC. Furthermore, obesity can affect the efficacy and side effects of multiple therapies such as surgery, radiotherapy, chemotherapy, endocrine therapy, immunotherapy and weight management of BC. In this review, we focus on the current landscape of the mechanisms of obesity in fueling BC and the impact of obesity on diverse therapeutic interventions. An in-depth exploration of the underlying mechanisms linking obesity and BC will improve the efficiency of the existing treatments and even provide novel treatment strategies for BC treatment.

Obesity induces gut microbiota alterations and augments acute graft-versus-host disease after allogeneic stem cell transplantation

The efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by acute and chronic graft-versus-host disease (GVHD). The impact of obesity on allo-HSCT outcomes is poorly understood. Here, we report that obesity had a negative and selective impact on acute gut GVHD after allo-HSCT in mice with diet-induced obesity (DIO). These animals exhibited increased gut permeability, endotoxin translocation across the gut, and radiation-induced gastrointestinal damage after allo-HSCT. After allo-HSCT, both male and female DIO mouse recipients showed increased proinflammatory cytokine production and expression of the GVHD marker ST2 (IL-33R) and MHC class II molecules; they also exhibited decreased survival associated with acute severe gut GVHD. This rapid-onset, obesity-associated gut GVHD depended on donor CD4⁺ T cells and occurred even with a minor MHC mismatch between donor and recipient animals. Retrospective analysis of clinical cohorts receiving allo-HSCT transplants from unrelated donors revealed that recipients with a high body mass index (BMI, >30) had reduced survival and higher serum ST2 concentrations compared with nonobese transplant recipients. Assessment of both DIO mice and allo-HSCT recipients with a high BMI revealed reduced gut microbiota diversity and decreased Clostridiaceae abundance. Prophylactic antibiotic treatment protected DIO mouse recipients from endotoxin translocation across the gut and increased inflammatory cytokine production, as well as gut pathology and mortality, but did not protect against later development of chronic skin GVHD. These results suggest that obesity-induced alterations of the gut microbiota may affect GVHD after allo-HSCT in DIO mice, which could be ameliorated by prophylactic antibiotic treatment.

Metabolic regulation in the immune response to cancer

Metabolic reprogramming in tumor‐immune interactions is emerging as a key factor affecting pro‐inflammatory carcinogenic effects and anticancer immune responses. Therefore, dysregulated metabolites and their regulators affect both cancer progression and therapeutic response. Here, we describe the molecular mechanisms through which microenvironmental, systemic, and microbial metabolites potentially influence the host immune response to mediate malignant progression and therapeutic intervention. We summarized the primary interplaying factors that constitute metabolism, immunological reactions, and cancer with a focus on mechanistic aspects. Finally, we discussed the possibility of metabolic interventions at multiple levels to enhance the efficacy of immunotherapeutic and conventional approaches for future anticancer treatments.

Rationale and clinical development of CD40 agonistic antibodies for cancer immunotherapy

Introduction: CD40 signaling activates dendritic cells leading to improved T cell priming against tumor antigens. CD40 agonism expands the tumor-specific T cell repertoire and has the potential to increase the fraction of patients that respond to established immunotherapies.Areas covered: This article reviews current as well as emerging CD40 agonist therapies with a focus on antibody-based therapies, including next generation bispecific CD40 agonists. The scientific rationale for different design criteria, binding epitopes, and formats are discussed.Expert opinion: The ability of CD40 agonists to activate dendritic cells and enhance antigen cross-presentation to CD8⁺ T cells provides an opportunity to elevate response rates of cancer immunotherapies. While there are many challenges left to address, including optimal dose regimen, CD40 agonist profile, combination partners and indications, we are confident that CD40 agonists will play an important role in the challenging task of reprogramming the immune system to fight cancer.

Association between body mass index, dosing strategy, and efficacy of immune checkpoint inhibitors

Background

Increased body mass index (BMI) has been associated with improved response to immune checkpoint inhibitors (ICIs) in multiple cancer types. We evaluated associations between BMI, ICI dosing strategy, and clinical outcomes.

Methods

We abstracted clinical data on patients with cancer treated with ICI, including age, sex, cancer type, BMI, ICI type, dosing strategy (weight-based or fixed), radiographic response, overall survival (OS), and progression-free survival (PFS). We compared clinical outcomes between low-BMI and high-BMI populations using Kaplan-Meier curves, Cox regressions, and Pearson product-moment correlation coefficients.

Results

A total of 297 patients were enrolled, of whom 40% were women and 59% were overweight (BMI≥25). Of these, 204 (69%) received fixed and 93 (31%) received weight-based ICI dosing. In the overall cohort, overweight BMI was associated with improved PFS (HR 0.69; 95% CI 0.51 to 0.94; p=0.02) and had a trend toward improved OS (HR 0.77; 95% CI 0.57 to 1.04; p=0.08). For both endpoints, improved outcomes in the overweight population were limited to patients who received weight-based ICI dosing (PFS HR 0.53; p=0.04 for weight-based; vs HR 0.79; p=0.2 for fixed dosing) (OS HR 0.56; p=0.03 for weight-based; vs HR 0.89; p=0.54 for fixed dosing). In multivariable analysis, BMI was not associated with PFS or OS. However, the interaction of BMI≥25 and weight-based dosing had a trend toward association with PFS (HR 0.53; 95% CI 0.26 to 1.10; p=0.09) and was associated with OS (HR 0.50; 95% CI 0.25 to 0.99; p=0.05). Patients with BMI<25 tended to have better outcomes with fixed-dose compared with weight-based ICI, while patients with BMI≥25 tended to have better outcomes with weight-based ICI, although these differences did not achieve statistical significance. There was no association between radiographic response and BMI with fixed-dose ICI (p=0.97), but a near-significant trend with weight-based ICI (p=0.1). In subset analyses, the association between BMI, ICI dosing strategy, and clinical outcomes appeared limited to men.

Conclusions

The clinical benefit of ICI in high-BMI populations appears limited to individuals receiving weight-based ICI dosing. Further research into optimal ICI dosing strategies may be warranted.

Towards Goals to Refine Prophylactic and Therapeutic Strategies Against COVID-19 Linked to Aging and Metabolic Syndrome

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) gave rise to the coronavirus disease 2019 (COVID-19) pandemic. A strong correlation has been demonstrated between worse COVID-19 outcomes, aging, and metabolic syndrome (MetS), which is primarily derived from obesity-induced systemic chronic low-grade inflammation with numerous complications, including type 2 diabetes mellitus (T2DM). The majority of COVID-19 deaths occurs in people over the age of 65. Individuals with MetS are inclined to manifest adverse disease consequences and mortality from COVID-19. In this review, we examine the prevalence and molecular mechanisms underlying enhanced risk of COVID-19 in elderly people and individuals with MetS. Subsequently, we discuss current progresses in treating COVID-19, including the development of new COVID-19 vaccines and antivirals, towards goals to elaborate prophylactic and therapeutic treatment options in this vulnerable population.

The role of macrophages in anti-tumor immune responses: pathological significance and potential as therapeutic targets

Malignant tumors comprise various types of normal cells and tumor cells, and are infiltrated by large numbers of immune cells, including macrophages. The results of numerous studies on the function and significance of intratumoral macrophages (tumor-associated macrophages) suggest that these macrophages generally enhance tumor progression rather than act as anti-tumor immune agents. Although much remains unknown, in this review, we attempt to describe the role of macrophages in the tumor microenvironment, and discuss their potential mechanisms on the recent immunotherapy.

The role of immune dysfunction in obesity-associated cancer risk, progression, and metastasis

Obesity has been linked to an increased risk of and a worse prognosis for several types of cancer. A number of interrelated mediators contribute to obesity's pro-tumor effects, including chronic adipose inflammation and other perturbations of immune cell development and function. Here, we review studies examining the impact of obesity-induced immune dysfunction on cancer risk and progression. While the role of adipose tissue inflammation in obesity-associated cancer risk has been well characterized, the effects of obesity on immune cell infiltration and activity within the tumor microenvironment are not well studied. In this review, we aim to highlight the impact of both adipose-mediated inflammatory signaling and intratumoral immunosuppressive signaling in obesity-induced cancer risk, progression, and metastasis.

Contribution of the tumor and obese microenvironment to triple negative breast cancer

The growing burden of obesity and incidence of the aggressive triple negative breast cancer (TNBC) is a challenge, especially amongst vulnerable populations with unmet medical needs and higher mortality from breast cancer. While some mechanisms linking obesity and TNBC have been identified, the complex nature of pathogenesis, in both obesity as well as TNBC poses a real challenge in establishing a causative role of obesity in risk of TNBC. In this review article, we discuss pathological mechanisms identified in the tumor microenvironment (TME) as well as the obese microenvironment (OME), such as inflammation, insulin resistance and survival pathways that contribute to the development and progression of TNBC. Insights into the cross-talk between TME and OME, and their contribution to TNBC development and progression, may pave the way for personalized therapies against TNBC progression, relapse and metastasis.

SARS-CoV-2 infection represents a high risk for the elderly: analysis of pathogenesis

As people get older, age-related alterations occur that lead to increased susceptibility to disease. In the current COVID-19 pandemic, older people are particularly susceptible to a SARS-CoV-2 infection developing into severe disease. The objective of this review was to examine the literature regarding factors that may explain the tendency of this population to develop severe COVID-19. Research articles considered in this review were searched for in EMBASE, PubMed, and Web of Science from December 2019 to December 2020. Citations were screened by two independent reviewers. Studies of the immune system in older individuals found alterations in both the adaptive and innate immune systems. The adaptive system is depressed in its functions, and the innate system is in a pro-inflammatory state that can lead to chronic disease. This pro-inflammatory state may be related to a severe course of disease in COVID-19. This review shows that the level of evidence supporting an association between immune alterations in the elderly and susceptibly to severe progression of SARS-CoV-2 infection is generally consistent. Preventive measures such as early antiviral treatment are of key importance for prevention of severe progression of COVID19.

Blueprint for cancer research: Critical gaps and opportunities

We are experiencing a revolution in cancer. Advances in screening, targeted and immune therapies, big data, computational methodologies, and significant new knowledge of cancer biology are transforming the ways in which we prevent, detect, diagnose, treat, and survive cancer. These advances are enabling durable progress in the goal to achieve personalized cancer care. Despite these gains, more work is needed to develop better tools and strategies to limit cancer as a major health concern. One persistent gap is the inconsistent coordination among researchers and caregivers to implement evidence-based programs that rely on a fuller understanding of the molecular, cellular, and systems biology mechanisms underpinning different types of cancer. Here, the authors integrate conversations with over 90 leading cancer experts to highlight current challenges, encourage a robust and diverse national research portfolio, and capture timely opportunities to advance evidence-based approaches for all patients with cancer and for all communities.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

Fructose Promotes Cytoprotection in Melanoma Tumors and Resistance to Immunotherapy

Checkpoint blockade immunotherapy relies on the empowerment of the immune system to fight cancer. Why some patients fail to achieve durable clinical responses is not well understood, but unique individual factors such as diet, obesity, and related metabolic syndrome could play a role. The link between obesity and patient outcomes remains controversial and has been mired by conflicting reports and limited mechanistic insight. We addressed this in a C57BL/6 mouse model of diet-induced obesity using a Western diet high in both fats and sugars. Obese mice bearing B16 melanoma or MC38 carcinoma tumors had impaired immune responses to immunotherapy and a reduced capacity to control tumor progression. Unexpectedly, these compromised therapeutic outcomes were independent of body mass and, instead, were directly attributed to dietary fructose. Melanoma tumors in mice on the high-fructose diet were resistant to immunotherapy and showed increased expression of the cytoprotective enzyme heme oxygenase-1 (HO-1). This increase in HO-1 protein was recapitulated in human A375 melanoma cells exposed to fructose in culture. Induced expression of HO-1 shielded tumor cells from immune-mediated killing and was critical for resistance to checkpoint blockade immunotherapy, which could be overcome in vivo using a small-molecule inhibitor of HO-1. This study reveals dietary fructose as a driver of tumor immune evasion, identifying HO-1 expression as a mechanism of resistance and a promising molecular target for combination cancer immunotherapy.See article by Khojandi et al., p. 214.

Obesity and Cancer Metastasis: Molecular and Translational Perspectives

Obesity is a modern health problem that has reached pandemic proportions. It is an established risk factor for carcinogenesis, however, evidence for the contribution of adipose tissue to the metastatic behavior of tumors is also mounting. Over 90% of cancer mortality is attributed to metastasis and metastatic tumor cells must communicate with their microenvironment for survival. Many of the characteristics observed in obese adipose tissue strongly mirror the tumor microenvironment. Thus in the case of prostate, pancreatic and breast cancer and esophageal adenocarcinoma, which are all located in close anatomical proximity to an adipose tissue depot, the adjacent fat provides an ideal microenvironment to enhance tumor growth, progression and metastasis. Adipocytes provide adipokines, fatty acids and other soluble factors to tumor cells whilst immune cells infiltrate the tumor microenvironment. In addition, there are emerging studies on the role of the extracellular vesicles secreted from adipose tissue, and the extracellular matrix itself, as drivers of obesity-induced metastasis. In the present review, we discuss the major mechanisms responsible for the obesity-metastatic link. Furthermore, understanding these complex mechanisms will provide novel therapies to halt the tumor-adipose tissue crosstalk with the ultimate aim of inhibiting tumor progression and metastatic growth.

PD-1 Blockade Reverses Obesity-Mediated T Cell Priming Impairment

Despite obesity reaching pandemic proportions, its impact on antigen-specific T cell responses is still unclear. We have recently demonstrated that obesity results in increased expression of PD-1 on T cells, and checkpoint blockade targeting PD-1/PD-L1 surprisingly resulted in greater clinical efficacy in cancer therapy. Adverse events associated with this therapy center around autoimmune reactions. In this study, we examined the impact of obesity on T cell priming and on autoimmune pathogenesis using the mouse model experimental autoimmune encephalomyelitis (EAE), which is mediated by autoreactive myelin-specific T cells generated after immunization. We observed that diet-induced obese (DIO) mice had a markedly delayed EAE onset and developed milder clinical symptoms compared to mice on control diet (CD). This delay was associated with impaired generation of myelin-specific T cell numbers and concurrently correlated with increased PD-L1 upregulation on antigen-presenting cells in secondary lymphoid organs. PD-1 blockade during the priming stage of EAE restored disease onset and severity and increased numbers of pathogenic CD4+ T cells in the central nervous system (CNS) of DIO mice to similar levels to those of CD mice. Administration of anti-PD-1 after onset of clinical symptoms did not increase EAE pathogenesis demonstrating that initial priming is the critical juncture affected by obesity. These findings demonstrate that obesity impairs antigen-specific T cell priming, but this can be reversed with PD-1 blockade. Our results further suggest that PD-1 blockade may increase the risk of autoimmune toxicities, particularly in obesity.

The effects of age and systemic metabolism on anti-tumor T cell responses

Average age and obesity prevalence are increasing globally. Both aging and obesity are characterized by profound systemic metabolic and immunologic changes and are cancer risk factors. The mechanisms linking age and body weight to cancer are incompletely understood, but recent studies have provided evidence that the anti-tumor immune response is reduced in both conditions, while responsiveness to immune checkpoint blockade, a form of cancer immunotherapy, is paradoxically intact. Dietary restriction, which promotes health and lifespan, may enhance cancer immunity. These findings illustrate that the systemic context can impact anti-tumor immunity and immunotherapy responsiveness. Here, we review the current knowledge of how age and systemic metabolic state affect the anti-tumor immune response, with an emphasis on CD8+ T cells, which are key players in anti-tumor immunity. A better understanding of the underlying mechanisms may lead to novel therapies enhancing anti-tumor immunity in the context of aging or metabolic dysfunction.

Aging, Male Sex, Obesity, and Metabolic Inflammation Create the Perfect Storm for COVID-19

Coronavirus disease 2019 (COVID-19) is a novel threat that seems to result from the collusion between a new pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and an existing pandemic of metabolic disease driven by obesity. This Perspective explores the evolving epidemiological, clinical, biological, and molecular evidence to propose an unfolding paradigm in which old age, chronic metabolic disease (such as obesity, type 2 diabetes, and metabolic syndrome), and male biological sex produce a deadly symbiosis of dysregulated immunometabolism and chronic systemic inflammation that intensifies virally induced hyperinflammation associated with SARS-CoV-2 infection. It is intended to inspire new research directions and stimulate funding in this field.

A public health perspective of aging: do hyper-inflammatory syndromes such as COVID-19, SARS, ARDS, cytokine storm syndrome, and post-ICU syndrome accelerate short- and long-term inflammaging?

A central clinical question as the world deals with the COVID-19 pandemic is what the long-term sequelae for the millions of individuals will be who recover from the hyperinflammatory state characterizing COVID-19 and in particular for the hundreds of thousands who are ill enough to need hospitalization and in particular ICU care. Even when the pandemic is finally controlled, will COVID-19 survivors face exaggerated internal inflammatory processes, worsening co-morbidities, and increased susceptibility to age-related diseases? Clues for what may happen in post-COVID-19 patients can be elicited from those who recovered from other conditions that lead to similar hyperinflammatory states such as Severe Acute Respiratory Syndrome (SARS), acute respiratory disease syndrome (ARDS), cytokine storm syndrome, and post-ICU syndrome. The short-and long-term sequalae following recovery from each of these conditions suggests that these syndromes lead to an accelerated state of chronic subclinical systemic inflammation often seen in aging (termed inflammaging) resulting in increased and worsening age-related conditions including frailty even in younger individuals.

The intrinsic and extrinsic elements regulating inflammation

Inflammation is a sophisticated biological tissue response to both extrinsic and intrinsic stimuli. Although the pathological aspects of inflammation are well appreciated, there are still rooms for understanding the physiological functions of the inflammation. Recent studies have focused on mechanisms, context and the role of physiological inflammation. Besides, there have been progress in the comprehension of commensal microbiota, immunometabolism, cancer and intracellular signaling events' roles that impact on the regulation of inflammation. Despite the fact that inflammatory responses are vital through tissue damage, understanding the mechanisms to turn off the finished or unnecessary inflammation is crucial for restoring homeostasis. Inflammation seems to be a smart process that acts like two edges of a sword, meaning that it has both protective and deleterious consequences. Knowing both edges and the regulation processes will help the future understanding and therapy for various diseases.

Hypercoagulopathy and Adipose Tissue Exacerbated Inflammation May Explain Higher Mortality in COVID-19 Patients With Obesity

COVID-19, caused by SARS-CoV-2, is characterized by pneumonia, lymphopenia, exhausted lymphocytes and a cytokine storm. Several reports from around the world have identified obesity and severe obesity as one of the strongest risk factors for COVID-19 hospitalization and mechanical ventilation. Moreover, countries with greater obesity prevalence have a higher morbidity and mortality risk of developing serious outcomes from COVID-19. The understanding of how this increased susceptibility of the people with obesity to develop severe forms of the SARS-CoV-2 infection occurs is crucial for implementing appropriate public health and therapeutic strategies to avoid COVID-19 severe symptoms and complications in people living with obesity. We hypothesize here that increased ACE2 expression in adipose tissue displayed by people with obesity may increase SARS-CoV-2 infection and accessibility to this tissue. Individuals with obesity have increased white adipose tissue, which may act as a reservoir for a more extensive viral spread with increased shedding, immune activation and pro-inflammatory cytokine amplification. Here we discuss how obesity is related to a pro-inflammatory and metabolic dysregulation, increased SARS-CoV-2 host cell entry in adipose tissue and induction of hypercoagulopathy, leading people with obesity to develop severe forms of COVID-19 and also death. Taken together, it may be crucial to better explore the role of visceral adipose tissue in the inflammatory response to SARS-CoV-2 infection and investigate the potential therapeutic effect of using specific target anti-inflammatories (canakinumab or anakinra for IL-1β inhibition; anti-IL-6 antibodies for IL-6 inhibition), anticoagulant or anti-diabetic drugs in COVID-19 treatment of people with obesity. Defining the immunopathological changes in COVID-19 patients with obesity can provide prominent targets for drug discovery and clinical management improvement.

Immunosuppression is Inappropriately Qualifying the Immune Status of Septic and SIRS Patients

Immunosuppression is the most commonly used concept to qualify the immune status of patients with either sterile systemic inflammatory response syndrome (SIRS) or sepsis. In this review we attempt to demonstrate that the concept of immunosuppression is an oversimplification of the complex anti-inflammatory response that occurs in patients dealing with a severe sterile or infectious insult. Particularly, the immune status of leukocytes varies greatly depending on the compartment from where they are derived from. Furthermore, although certain functions of immune cells present in the blood stream or in the hematopoietic organs can be significantly diminished, other functions are either unchanged or even enhanced. This juxtaposition illustrates that there is no global defect. The mechanisms called reprogramming or trained innate immunity are probably aimed at preventing a generalized deleterious inflammatory reaction, and work to maintain the defense mechanisms at their due levels.

High prevalence for obesity in severe COVID-19: Possible links and perspectives towards patient stratification

It is becoming obvious that in addition to aging and various hearth pathologies, excess of body weight, especially obesity is a major risk factor for severity of COVID-19 infection. Intriguingly the receptor for SARS-CoV-2 is ACE2, a member of the angiotensin receptor family that has a relatively large tissue distribution. This observation likely explains the multitude of symptoms that have been described from human patients. The adipose tissue also expresses ACE2, suggesting that adipocytes are potentially infected by SARS-CoV-2. Here we discuss some of the potential contribution of the adipose tissue to the severity of the infection and propose some aspects of obese patients metabolic phenotyping to help stratification of individuals with high risk of severe disease.

Why does COVID-19 disproportionately affect older people?

The severity and outcome of coronavirus disease 2019 (COVID-19) largely depends on a patient's age. Adults over 65 years of age represent 80% of hospitalizations and have a 23-fold greater risk of death than those under 65. In the clinic, COVID-19 patients most commonly present with fever, cough and dyspnea, and from there the disease can progress to acute respiratory distress syndrome, lung consolidation, cytokine release syndrome, endotheliitis, coagulopathy, multiple organ failure and death. Comorbidities such as cardiovascular disease, diabetes and obesity increase the chances of fatal disease, but they alone do not explain why age is an independent risk factor. Here, we present the molecular differences between young, middle-aged and older people that may explain why COVID-19 is a mild illness in some but life-threatening in others. We also discuss several biological age clocks that could be used in conjunction with genetic tests to identify both the mechanisms of the disease and individuals most at risk. Finally, based on these mechanisms, we discuss treatments that could increase the survival of older people, not simply by inhibiting the virus, but by restoring patients' ability to clear the infection and effectively regulate immune responses.