Neutrophil ageing and immunesenescence

The Impact of Aging and Toll-like Receptor 2 Deficiency on the Clinical Outcomes of Staphylococcus aureus Bacteremia

Staphylococcus aureus (S. aureus) causes a broad range of infections. Toll-like receptor (TLR) 2 senses the S. aureus lipoproteins in S. aureus infections. Aging raises the risk of infection. Our aim was to understand how aging and TLR2 affect the clinical outcomes of S. aureus bacteremia. Four groups of mice (wild type/young, wild type/old, TLR2-/-/young, and TLR2-/-/old) were intravenously infected with S. aureus, and the infection course was followed. Both TLR2 deficiency and aging enhanced the susceptibility to disease. Increased age was the main contributing factor for increased mortality rates and changes in spleen weight, whereas other clinical parameters, such as weight loss and kidney abscess formation, were more TLR2 dependent. Importantly, aging increased mortality rates without relying on TLR2. In vitro, both aging and TLR2 deficiency down-regulated cytokine/chemokine production of immune cells with distinct patterns. In summary, we demonstrate that aging and TLR2 deficiency impair the immune response to S. aureus bacteremia in distinct ways.

Immunosenescence as a convergence pathway in neurodegeneration

Immunity refers to the body's defense mechanism to protect itself against illness or to produce antibodies against pathogens. Senescence is a cellular phenomenon that integrates a sustainable growth restriction, other phenotypic abnormalities and including a pro-inflammatory secretome. It is highly involved in regulating developmental stages, tissue homeostasis, and tumor proliferation monitoring. Contemporary experimental reports imply that abolition of senescent cells employing evolved genetic and therapeutic approaches augment the chances of survival and boosts the health span of an individual. Immunosenescence is considered as a process in which dysfunction of the immune system occurs with aging and greatly includes remodeling of lymphoid organs. This in turn causes fluctuations in the immune function of the elderly that has strict relation with the expansion of autoimmune diseases, infections, malignant tumors and neurodegenerative disorders. The interaction of the nervous and immune systems during aging is marked by bi-directional influence and mutual correlation of variations. The enhanced systemic inflammatory condition in the elderly, and the neuronal immune cell activity can be modulated by inflamm-aging and peripheral immunosenescence resulting in chronic low-grade inflammatory processes in the central Nervous system known as neuro-inflammaging. For example, glia excitation by cytokines and glia pro-inflammatory productions contribute significantly to memory injury as well as in acute systemic inflammation, which is associated with high levels of Tumor necrosis factor -α and a rise in cognitive decline. In recent years its role in the pathology of Alzheimer's disease has caught research interest to a large extent. This article reviews the connection concerning the immune and nervous systems and highlights how immunosenescence and inflamm-aging can affect neurodegenerative disorders.

KRIT1-mediated regulation of neutrophil adhesion and motility

Loss of Krev interaction-trapped-1 (KRIT1) expression leads to the development of cerebral cavernous malformations (CCM), a disease in which abnormal blood vessel formation compromises the structure and function of the blood-brain barrier. The role of KRIT1 in regulating endothelial function is well-established. However, several studies have suggested that KRIT1 could also play a role in regulating nonendothelial cell types and, in particular, immune cells. In this study, we generated a mouse model with neutrophil-specific deletion of KRIT1 in order to investigate the effect of KRIT1 deficiency on neutrophil function. Neutrophils isolated from adult Ly6Gtm2621(cre)Arte Krit1flox/flox mice had a reduced ability to attach and spread on the extracellular matrix protein fibronectin and exhibited a subsequent increase in migration. However, adhesion to and migration on ICAM-1 was unchanged. In addition, we used a monomeric, fluorescently-labelled fragment of fibronectin to show that integrin activation is reduced in the absence of KRIT1 expression, though β1 integrin expression appears unchanged. Finally, neutrophil migration in response to lipopolysaccharide-induced inflammation in the lung was decreased, as shown by reduced cell number and myeloperoxidase activity in lavage samples from Krit1PMNKO mice. Altogether, we show that KRIT1 regulates neutrophil adhesion and migration, likely through regulation of integrin activation, which can lead to altered inflammatory responses in vivo.

Immunosenescence and inflammaging in the aged horse

The equine population in the United States and worldwide now includes a higher percentage of geriatric horses than ever previously recorded, and as methods to treat and manage elderly equids are developed and refined, this aging population will likely continue to expand. A better understanding of how horses age and the effect of age on immunity and disease susceptibility is needed to enable targeted preventative healthcare strategies for aged horses. This review article outlines the current state of knowledge regarding the effect of aging on immunity, vaccine responsiveness, and disease risk in the horse, highlighting similarities and differences to what is observed in aged humans. Horses show similar but milder age-related alterations in immune function to those reported in people. Decreases in lymphocyte proliferation and antibody production and diminished response to vaccination have all been documented in elderly horses, however, increased risk of infectious disease is not commonly reported. Aged horses also show evidence of a proinflammatory state (inflammaging) yet appear less susceptible to the chronic diseases of people for which inflammation is a risk factor. Information is currently lacking as to why the horse does not experience the same risk of age-related disease (e.g., cancer, heart disease, neurodegeneration) as people, although a lack of negative lifestyle habits, differences in diet, exercise, genetics and physiology may all contribute to improved health outcomes in the older horse.

Altered transcriptional responses in the lungs of aged mice after influenza infection

Background

Influenza causes a serious infection in older individuals who are at the highest risk for mortality from this virus. Changes in the immune system with age are well known. This study used transcriptomic analysis to evaluate how aging specifically affects the functional host response to influenza in the lung. Adult (12–16 weeks) and aged (72–76 weeks) mice were infected with influenza and lungs were processed for RNA analysis.

Results

Older mice demonstrated a delayed anti-viral response on the level of transcription compared to adults, similar to the immunologic responses measured in prior work. The transcriptional differences, however, were evident days before observable differences in the protein responses described previously. The transcriptome response to influenza in aged mice was dominated by immunoglobulin genes and B cell markers compared to adult animals, suggesting immune dysregulation. Despite these differences, both groups of mice had highly similar transcriptional responses involving non-immune genes one day after inoculation and T cell genes during resolution.

Conclusions

These results define a delayed and dysregulated immune response in the lungs of aged mice infected with influenza. The findings implicate B cells and immunoglobulins as markers or mechanisms of immune aging. In addition to discovering new therapeutic targets, the findings underscore the value of transcription studies and network analysis to characterize complex biological processes, and serve as a model to analyze the susceptibility of the elderly to infectious agents.

Supplementary information

The online version contains supplementary material available at 10.1186/s12979-022-00286-9.

Age-related decline in the resistance of mice to bacterial infection and in LPS/TLR4 pathway-dependent neutrophil responses

Host defense against bacterial and fungal infections diminishes with age. In humans, impaired neutrophil responses are thought to contribute to this decline. However, it remains unclear whether neutrophil responses are also impaired in old mice. Here, we investigated neutrophil function in old mice, focusing on responses primed by lipopolysaccharide (LPS), an endotoxin released by gram-negative bacteria like E. coli, which signals through toll-like receptor (TLR) 4. We show that old mice have a reduced capacity to clear pathogenic E. coli during septic peritonitis. Neutrophil recruitment was elevated during LPS-induced but not aseptic peritonitis. Neutrophils from old mice showed reduced killing of E. coli. Their reactive oxygen species (ROS) production was impaired upon priming with LPS but not with GM-CSF/TNFα. Phagocytosis and degranulation were reduced in a partially LPS-dependent manner, whereas impairment of NET release in response to S. aureus was independent of LPS. Unexpectedly, chemotaxis was normal, as were Rac1 and Rac2 GTPase activities. LPS-primed activation of Erk and p38 Mapk was defective. PIP₃ production was reduced upon priming with LPS but not with GM-CSF/TNFα, whereas PIP₂ levels were constitutively low. The expression of 5% of neutrophil proteins was dysregulated in old age. Granule proteins, particularly cathepsins and serpins, as well as TLR-pathway proteins and membrane receptors were upregulated, whereas chromatin and RNA regulators were downregulated. The upregulation of CD180 and downregulation of MyD88 likely contribute to the impaired LPS signaling. In summary, all major neutrophil responses except chemotaxis decline with age in mice, particularly upon LPS priming. This LPS/TLR4 pathway dependence resolves previous controversy regarding effects of age on murine neutrophils and confirms that mice are an appropriate model for the decline in human neutrophil function.

Investigating population-level immunosenescence: From bench to bedside

The immune response is remodeled with aging in a process called immunosenescence. Some immunologists conceive immunosenescence as an adaptation of immunity to the aged immune-environment rather than a merely collapsed reactivity of immune cells against microbes and tumor cells. Others believe on an uninterrupted activation of the innate immune system with aging, leading to a low grade, sterile and chronic proinflammatory state called inflammaging. For instance, it is possible that chronic infection by cytomegalovirus leads to persistent production of viral load. This phenomenon offers periodic stimuli to the immune system that ultimately contribute to the remodeling of the immune response. If investigating immunosenescence at the cellular level is already a difficult task, considering the population level is much more complex. However, by studying immunosenescence at the population level, we can extract valuable results with viable applications. While studies with animal models allow scientists to deepen their understanding of the mechanisms of immunosenescence, studying large populations can bring practical innovations to medicine and the health system. Many researchers and funders have dedicated themselves to producing methods for the evaluation of immunosenescence on a large scale, aiming to elucidate new mechanisms by which diseases are established in the elderly. The description of how the immune response is remodeled with aging emerges as a new tool to identify the subset of subjects in which unhealthy aging is a matter of time, to help better individualize clinical management and select patients who may benefit. of early interventions. This review focuses on functional assays as valuable methods for measuring the remodeling of the immune response with aging and discuss their clinical impact. We also recall fundamental concepts for understanding the aging process of the immune response. In addition, we highlight future prospects for immunosenescence research.

Clinical and Phenotypic Characterization of Common Variable Immunodeficiency Diagnosed in Younger and Older Adults

PURPOSE

Common variable immunodeficiency (CVID) is the most prevalent symptomatic immunodeficiency in adults. Little is known about the manifestations of CVID presenting in older adults. Herein, we performed a phenotypic characterization of patients diagnosed older than age 40.

METHODS

A retrospective chart review of 79 patients seen at UF Health between 2006 and 2020 with a verified diagnosis of CVID per the ICON 2016 criteria was conducted. Patients were classified according to four phenotypes: no-disease-related complications, autoimmune cytopenias, polyclonal lymphoproliferation, and unexplained enteropathy. Patients diagnosed with CVID from age 2 to 40 (n = 41, "younger cohort") were compared to patients diagnosed with CVID age 41 and older (n = 38, "older cohort").

RESULTS

Among the younger cohort, pathologic genetic variants, positive family history for immunodeficiency, autoimmunity (49% vs 24%, p = 0.03), and splenomegaly (46% vs 16%, p = 0.004) were more common, as was the "autoimmune cytopenias" phenotype (24% vs 3%, p = 0.007). Among the older cohort, lymphoma (11% vs 0%, p = 0.049) and the "no disease-related complications" phenotype (79% vs 57%, p = 0.03) were more commonly seen. Comorbidities such as bronchiectasis (27% vs 21%, p = 0.61), GI involvement (34% vs 24%, p = 0.33), and GLILD (5% vs 8%, p = 0.67) were equally present among both the younger and older cohorts, respectively.

CONCLUSION

The lower incidence of autoimmunity and splenomegaly, as well as overlapping clinical features with immunosenescence, may make diagnosing CVID in older patients more challenging; however, the disease is not more indolent as the risks for lymphoma, bronchiectasis, and GLILD are similar to those of younger patients.

JDSNMF: Joint Deep Semi-Non-Negative Matrix Factorization for Learning Integrative Representation of Molecular Signals in Alzheimer's Disease

High dimensional multi-omics data integration can enhance our understanding of the complex biological interactions in human diseases. However, most studies involving unsupervised integration of multi-omics data focus on linear integration methods. In this study, we propose a joint deep semi-non-negative matrix factorization (JDSNMF) model, which uses a hierarchical non-linear feature extraction approach that can capture shared latent features from the complex multi-omics data. The extracted latent features obtained from JDSNMF enabled a variety of downstream tasks, including prediction of disease and module analysis. The proposed model is applicable not only to sample-matched multiple data (e.g., multi-omics data from one cohort) but also to feature-matched multiple data (e.g., omics data from multiple cohorts), and therefore it can be flexibly applied to various cases. We demonstrate the capabilities of JDSNMF using sample-matched simulated data and feature-matched multi-omics data from Alzheimer’s disease cohorts, evaluating the feature extraction performance in the context of classification. In a test application, we identify AD- and age-related modules from the latent matrices using an explainable artificial intelligence and regression model. These results show that the JDSNMF model is effective in identifying latent features having a complex interplay of potential biological signatures.

New Pharmacological Tools to Target Leukocyte Trafficking in Lung Disease

Infection and inflammation of the lung results in the recruitment of non-resident immune cells, including neutrophils, eosinophils and monocytes. This swift response should ensure clearance of the threat and resolution of stimuli which drive inflammation. However, once the threat is subdued this influx of immune cells should be followed by clearance of recruited cells through apoptosis and subsequent efferocytosis, expectoration or retrograde migration back into the circulation. This cycle of cell recruitment, containment of threat and then clearance of immune cells and repair is held in exquisite balance to limit host damage. Advanced age is often associated with detrimental changes to the balance described above. Cellular functions are altered including a reduced ability to traffic accurately towards inflammation, a reduced ability to clear pathogens and sustained inflammation. These changes, seen with age, are heightened in lung disease, and most chronic and acute lung diseases are associated with an exaggerated influx of immune cells, such as neutrophils, to the airways as well as considerable inflammation. Indeed, across many lung diseases, pathogenesis and progression has been associated with the sustained presence of trafficking cells, with examples including chronic diseases such as Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis and acute infections such as Pneumonia and Pneumonitis. In these instances, there is evidence that dysfunctional and sustained recruitment of cells to the airways not only increases host damage but impairs the hosts ability to effectively respond to microbial invasion. Targeting leukocyte migration in these instances, to normalise cellular responses, has therapeutic promise. In this review we discuss the current evidence to support the trafficking cell as an immunotherapeutic target in lung disease, and which potential mechanisms or pathways have shown promise in early drug trials, with a focus on the neutrophil, as the quintessential trafficking immune cell.

Dysregulation of Systemic Immunity in Aging and Dementia

Neuroinflammation and the tissue-resident innate immune cells, the microglia, respond and contribute to neurodegenerative pathology. Although microglia have been the focus of work linking neuroinflammation and associated dementias like Alzheimer's Disease, the inflammatory milieu of brain is a conglomerate of cross-talk amongst microglia, systemic immune cells and soluble mediators like cytokines. Age-related changes in the inflammatory profile at the levels of both the brain and periphery are largely orchestrated by immune system cells. Strong evidence indicates that both innate and adaptive immune cells, the latter including T cells and B cells, contribute to chronic neuroinflammation and thus dementia. Neurodegenerative hallmarks coupled with more traditional immune system stimuli like infection or injury likely combine to trigger and maintain persistent microglial and thus brain inflammation. This review summarizes age-related changes in immune cell function, with special emphasis on lymphocytes as a source of inflammation, and discusses how such changes may potentiate both systemic and central nervous system inflammation to culminate in dementia. We recap the understudied area of AD-associated changes in systemic lymphocytes in greater detail to provide a unifying perspective of inflammation-fueled dementia, with an eye toward evidence of two-way communication between the brain parenchyma and blood immune cells. We focused our review on human subjects studies, adding key data from animal models as relevant.

Combination of the Probiotics Lacticaseibacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis, BB-12 Has Limited Effect on Biomarkers of Immunity and Inflammation in Older People Resident in Care Homes: Results From the Probiotics to Reduce Infections iN CarE home reSidentS Randomized, Controlled Trial

Aging is associated with a decline in many components of the immune system (immunosenescence). Probiotics may improve the immune response in older people. The objective was to determine the effect of the combination of two probiotic organisms [Lacticaseibacillus (previously known as Lactobacillus) rhamnosus GG (LGG) and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12)] on a range of immune biomarkers measured in the blood of older people resident in care homes in the UK. In a randomized controlled trial, older people [aged 67-97 (mean 86) years] resident in care homes received the combination of LGG+BB-12 (1.3-1.6 × 10⁹ CFU per day) or placebo for up to 12 months. Full blood count, blood immune cell phenotypes, plasma immune mediator concentrations, phagocytosis, and blood culture responses to immune stimulation were all measured. Response to seasonal influenza vaccination was measured in a subset of participants. Paired samples (i.e., before and after intervention) were available for 30 participants per group. LGG and BB-12 were more likely to be present in feces in the probiotic group and were present at higher numbers. There was no significant effect of the probiotics on components of the full blood count, blood immune cell phenotypes, plasma immune mediator concentrations, phagocytosis by neutrophils and monocytes, and blood culture responses to immune stimulation. There was an indication that the probiotics improved the response to seasonal influenza vaccination with significantly (p = 0.04) higher seroconversion to the A/Michigan/2015 vaccine strain in the probiotic group than in the placebo group (47 vs. 15%).

The twilight of the immune system: The impact of immunosenescence in aging

Cellular senescence is a critical part of human anti-tumor defence; however, the accumulation of senescent cells with age underpins a wide range of pathologies. Senescent change in immune cells, or immunosenescence, has a wide range of physiological effects and is at least partially responsible for many diseases associated with aging. Immunosenescence underpins inflammaging, increased vulnerability to infectious disease with age, malignant change in the elderly, and auto-immunity. Understanding the effects and mechanisms of immunosenescence will improve disease outcomes and prevention in older adults, and generate new treatments for common illnesses. In this review we summarize the key changes occurring in immunosenescence across each facet of the immune system, and identify their clinical correlates.

The Interplay between Immunosenescence and Microbiota in the Efficacy of Vaccines

Vaccinations are among the most effective medical procedures and have had an incredible impact on almost everyone’s life. One of the populations that can benefit the most from them are elderly people. Unfortunately, in this group, vaccines are less effective than in other groups, due to immunosenescence. The immune system ages like the whole body and becomes less effective in responding to infections and vaccinations. At the same time, immunosenescence also favors an inflammatory microenvironment, which is linked to many conditions typical of the geriatrics population. The microbiota is one of the key actors in modulating the immune response and, in this review, we discuss the current evidence on the role of microbiota in regulating the immune response to vaccines, particularly in elderly people.

Remodeling of the Immune Response With Aging: Immunosenescence and Its Potential Impact on COVID-19 Immune Response

Elderly individuals are the most susceptible to an aggressive form of coronavirus disease (COVID-19), caused by SARS-CoV-2. The remodeling of immune response that is observed among the elderly could explain, at least in part, the age gradient in lethality of COVID-19. In this review, we will discuss the phenomenon of immunosenescence, which entails changes that occur in both innate and adaptive immunity with aging. Furthermore, we will discuss inflamm-aging, a low-grade inflammatory state triggered by continuous antigenic stimulation, which may ultimately increase all-cause mortality. In general, the elderly are less capable of responding to neo-antigens, because of lower naïve T cell frequency. Furthermore, they have an expansion of memory T cells with a shrinkage of the T cell diversity repertoire. When infected by SARS-CoV-2, young people present with a milder disease as they frequently clear the virus through an efficient adaptive immune response. Indeed, antibody-secreting cells and follicular helper T cells are thought to be effectively activated in young patients that present a favorable prognosis. In contrast, the elderly are more prone to an uncontrolled activation of innate immune response that leads to cytokine release syndrome and tissue damage. The failure to trigger an effective adaptive immune response in combination with a higher pro-inflammatory tonus may explain why the elderly do not appropriately control viral replication and the potential clinical consequences triggered by a cytokine storm, endothelial injury, and disseminated organ injury. Enhancing the efficacy of the adaptive immune response may be an important issue both for infection resolution as well as for the appropriate generation of immunity upon vaccination, while inhibiting inflamm-aging will likely emerge as a potential complementary therapeutic approach in the management of patients with severe COVID-19.

Clinical assessment of risk factors for infection in inflammatory bowel disease patients

PURPOSE

Recognizing patients with inflammatory bowel disease who are prone to infection would enable the adjustment of the type and intensity of immunosuppressive treatment. The aim of this study was to identify a clinical profile of risk for infections in IBD patients, based on the interaction of immunosuppressive treatment with factors inherent to the patient.

METHODS

A case-control study was performed among patients older than 18 years. Patients with any significant infection (any kind of severe or recurrent infection according to standard clinical criteria or a critical enough infection according to the patient) were defined as cases. Both cases and controls were randomly selected in a 1:3 ratio. All the period from diagnosis to the end of recruitment (June 2016) was analyzed. Risk factors for infection were identified by logistic regression analysis; the strength of association was reported by odds ratio (OR) with 95% confidence interval (95%CI).

RESULTS

A total of 112 cases and 270 controls were included. The independent risk factors for significant infection are the number of immunosuppressants (one drug: OR 1.28, 95% CI 0.53-3.11, two drugs: OR 2.37, 95% CI 1.01-5,56, and three drugs: OR 5.84, 95% CI 1.57-21.72), body mass index (OR 1.08; 95 %CI 1,01-1,16), the degree of comorbidity (OR 1.52; 95% CI 1.04-2.21), and the intensity of inflammatory activity (OR 1.43; 95% CI 1.19-1.71).

CONCLUSIONS

Regardless of immunosuppression, several patient factors such as comorbidity, body mass index, or the inflammatory activity of the disease determine the individual risk of infectious complications and should be considered for an adequate risk assessment.

Alpha-1 Antitrypsin Deficiency and Accelerated Aging: A New Model for an Old Disease?

Alpha-1 antitrypsin (AAT) protects the lung by inhibiting neutrophil proteinases, but AAT has many other non-proteolytic functions that are anti-inflammatory, antiviral and homeostatic. Approximately 1 in 1600 to 1 in 5000 people have the homozygous Z mutation, which causes AAT misfolding, accumulation in (predominantly) liver cells and low circulating levels of AAT, leading to AAT deficiency (AATD). AATD is classically a disease of neutrophilic inflammation, with an aggressive and damaging innate immune response contributing to emphysema and other pathologies. AATD is one of the most common genetic disorders but considerably under-recognised. Most patients are diagnosed later in life, by which time they may have accumulated significant lung, liver and multisystem damage. Disease presentation is heterogeneous and not fully explained by deficiency levels alone or exposure to cigarette smoking. This suggests other factors influence AATD-associated pathological processes. Aging itself is associated with organ dysfunction, including emphysema and airflow obstruction, inflammation, altered immune cell responses (termed immunosenescence) and a loss of proteostasis. Many of these processes are present in AATD but at an earlier age and more advanced stage compared with chronological aging alone. Augmentation therapy does not completely abrogate the manifold disease processes present in AATD. New approaches are needed. There is emerging evidence that both age- and AATD-related disease processes are amenable to correction by targeting proteostasis, autophagy, immunosenescence and epigenetic factors. This review explores the impact of the aging process on AATD presentation and discusses novel therapeutic strategies to mitigate low levels of AAT or misfolded AAT in an aging host.

Peripheral Immunity, Immunoaging and Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder among elderly population, characterized by the progressive degeneration of dopaminergic neurons in the midbrain. To date, exact cause remains unknown and the mechanism of neurons death uncertain. It is typically considered as a disease of central nervous system (CNS). Nevertheless, numerous evidence has been accumulated in several past years testifying undoubtedly about the principal role of neuroinflammation in progression of PD. Neuroinflammation is mainly associated with presence of activated microglia in brain and elevated levels of cytokine levels in CNS. Nevertheless, active participation of immune system as well has been noted, such as, elevated levels of cytokine levels in blood, the presence of auto antibodies, and the infiltration of T cell in CNS. Moreover, infiltration and reactivation of those T cells could exacerbate neuroinflammation to greater neurotoxic levels. Hence, peripheral inflammation is able to prime microglia into pro-inflammatory phenotype, which can trigger stronger response in CNS further perpetuating the on-going neurodegenerative process. In the present review, the interplay between neuroinflammation and the peripheral immune response in the pathobiology of PD will be discussed. First of all, an overview of regulation of microglial activation and neuroinflammation is summarized and discussed. Afterwards, we try to collectively analyze changes that occurs in peripheral immune system of PD patients, suggesting that these peripheral immune challenges can exacerbate the process of neuroinflammation and hence the symptoms of the disease. In the end, we summarize some of proposed immunotherapies for treatment of PD.

Surgical Site Infections in Aesthetic Surgery

Surgical site infections represent one of the most common postoperative complications in patients undergoing aesthetic surgery. As with other postoperative complications, the incidence of these infections may be influenced by many factors and varies depending on the specific operation performed. Understanding the risk factors for infection development is critical because careful patient selection and appropriate perioperative counseling will set the right expectations and can ultimately improve patient outcomes and satisfaction. Various perioperative prevention measures may also be employed to minimize the incidence of these infections. Once the infection occurs, prompt diagnosis will allow management of the infection and any associated complications in a timely manner to ensure patient safety, optimize the postoperative course, and avoid long-term sequelae.

Age-related DNA hydroxymethylation is enriched for gene expression and immune system processes in human peripheral blood

DNA methylation (DNAm) has a well-established association with age in many tissues, including peripheral blood mononuclear cells (PBMCs). Compared to DNAm, the closely related epigenetic modification known as DNA hydroxymethylation (DNAhm) was much more recently discovered in mammals. Preliminary investigations have observed a positive correlation between gene body DNAhm and cis-gene expression. While some of these studies have observed an association between age and global DNAhm, none have investigated region-specific age-related DNAhm in human blood samples. In this study, we investigated DNAhm and gene expression in PBMCs of 10 young and 10 old, healthy female volunteers. Thousands of regions were differentially hydroxymethylated in the old vs. young individuals in gene bodies, exonic regions, enhancers, and promoters. Consistent with previous work, we observed directional consistency between age-related differences in DNAhm and gene expression. Further, age-related DNAhm and genes with high levels of DNAhm were enriched for immune system processes which may support a role of age-related DNAhm in immunosenescence.

Neutrophil phenotypes in chronic lung disease

Introduction: Neutrophils are the most abundant inflammatory cells in the lungs of patients with chronic lung diseases, especially COPD, yet despite this, patients often experience repeated chest infections. Neutrophil function may be altered in disease, but the reasons are unclear. In chronic disease, sequential pro-inflammatory and pro-repair responses appear distorted. As understanding of neutrophil heterogeneity has expanded, it is suggested that different neutrophil phenotypes may impact on health and disease. Areas covered: In this review, the definition of cellular phenotype, the implication of neutrophil surface markers and functions in chronic lung disease and the complex influences of external, local and genetic factors on these changes are discussed. Literature was accessed up to the 19 July 2019 using: PubMed, US National Library of Medicine National Institutes of Health and the National Centre for Biotechnology Information. Expert opinion: As more is learned about neutrophils, the further we step from the classical view of neutrophils being unrefined killing machines to highly complex and finely tuned cells. Future therapeutics may aim to normalize neutrophil function, but to achieve this, knowledge of phenotypes in humans and how these relate to observed pathology and disease processes is required.

Novel findings in neutrophil biology and their impact on cardiovascular disease

Neutrophils are the most abundant circulating leucocytes in healthy humans. These cells are central players during acute inflammatory responses, although a growing body of evidence supports a crucial role in chronic inflammation and chemokines and cytokines related to it as well. Thus, both humoral and cellular components are involved in the development of plaque formation and atherosclerosis. Accordingly, CANTOS trial using an interleukin-1 beta antibody confirmed that inflammatory cytokines contribute to the occurrence of myocardial infarction and cardiac death independent of changes in lipids. Recent data revealed that neutrophils are a heterogeneous population with different subsets and functional characteristics (i.e. CD177+ cells, OLFM4+ neutrophils, proangiogenic neutrophils, neutrophils undergoing reverse migration, and aged neutrophils). Importantly, neutrophils are able to synthesize de novo proteins. Neutrophil extracellular trap generation and NETosis have been considered as very important weapons in sterile inflammation. Neutrophil-derived microvesicles represent another mechanism by which neutrophils amplify inflammatory processes, being found at high levels both at the site of injury and in the bloodstream. Finally, neutrophil aging can influence their functions also in relation with host age. These recent acquisitions in the field of neutrophil biology might pave the way for new therapeutic targets to prevent or even treat patients experiencing cardiovascular (CV) diseases. Here, we discuss novel findings in neutrophil biology, their impact on CV and cerebrovascular diseases, and the potential implementation of these notions into daily clinical practice.

How Could We Slow or Reverse the Human Aging Process and Extend the Healthy Life Span with Heterochronous Autologous Hematopoietic Stem Cell Transplantation

The senescence of the immune system contributes considerably to the age-related diseases that are the main causes of death after the age of 65. In this study, we present an appealing option for the prevention of immune senescence and slowing or reversing the aging process, which can be achieved by heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow stem cells are collected from donors while young, cryopreserved and stored for a long period, and reinfused at a later time when indicated. After reinfusion and homing, these young HSCs could participate in normal hemato- and immunopoiesis and improve several immune functions by expanding the immune- as well as hematopoietic cell repertoire. Several animal studies have already confirmed the feasibility of this procedure, which extended the longevity of the treated animals. If translated to human medicine, haHSCT could prevent or mitigate age-related immune defects and extend the healthy life span. In this review, we describe the concept of haHSCT, recent studies that confirm its feasibility, and discuss the further research needed to translate this heterochronous methodology.

Older Adult Patients Are at Lower Risk of ARDS Compared to Younger Patients at Risk: Secondary Analysis of a Multicenter Cohort Study

INTRODUCTION

Older adult individuals often have acute illnesses predisposing them to developing acute respiratory distress syndrome (ARDS). We aimed to identify the relationship between age and the development of ARDS in a cohort of hospitalized patients.

METHODS

This was a secondary analysis of a prospective multicenter observational cohort study of hospitalized patients at risk of developing ARDS admitted to 22 hospitals from March 2009 to August 2009. Patients were classified as older adults if their age was 80 or greater. A multivariable logistic regression was performed, adjusting for severity of illness via Acute Physiology and Chronic Health Evaluation (APACHE II) and risk of ARDS via Lung Injury Prediction Score.

RESULTS

Of 5584 patients, 377 (6.8%) developed ARDS. Twenty-four (3.5%) of 694 patients aged 80 or older developed ARDS, compared to 353 (7.2%) of 4890 patients aged less than 80 (P < .001). After adjusting for severity of illness and the risk of ARDS development, older adult patients had a lower incidence of ARDS compared to younger individuals (odds ratio: 0.28, 95% confidence interval: 0.18-0.42).

CONCLUSION

Older adult patients aged 80 years or older have a reduced incidence of ARDS compared to younger patients, after adjusting for severity of illness and risk of ARDS development.

The role of DNA methylation and hydroxymethylation in immunosenescence

A healthy functioning immune system is critical to stave off infectious diseases, but as humans and other organisms age, their immune systems decline. As a result, diseases that were readily thwarted in early life pose nontrivial harm and can even be deadly in late life. Immunosenescence is defined as the general deterioration of the immune system with age, and it is characterized by functional changes in hematopoietic stem cells (HSCs) and specific blood cell types as well as changes in levels of numerous factors, particularly those involved in inflammation. Potential mechanisms underlying immunosenescence include epigenetic changes such as changes in DNA methylation (DNAm) and DNA hydroxymethylation (DNAhm) that occur with age. The purpose of this review is to describe what is currently known about the relationship between immunosenescence and the age-related changes to DNAm and DNAhm, and to discuss experimental approaches best suited to fill gaps in our understanding.

Putative Inflammatory Sensitive Mechanisms Underlying Risk or Resilience to Social Stress

It has been well recognized that exposure to stress can lead to the onset of psychosocial disorders such as depression. While there are a number of antidepressant therapies currently available and despite producing immediate neurochemical alterations, they require weeks of continuous use in order to exhibit antidepressant efficacy. Moreover, up to 30% of patients do not respond to typical antidepressants, suggesting that our understanding of the pathophysiology underlying stress-induced depression is still limited. In recent years inflammation has become a major focus in the study of depression as several clinical and preclinical studies have demonstrated that peripheral and central inflammatory mediators, including interleukin (IL)-1β, are elevated in depressed patients. Moreover, it has been suggested that inflammation and particularly neuroinflammation may be a direct and immediate link in the emergence of stress-induced depression due to the broad neural and glial effects that are elicited by proinflammatory cytokines. Importantly, individual differences in inflammatory reactivity may further explain why certain individuals exhibit differing susceptibility to the consequences of stress. In this review article, we discuss sources of individual differences such as age, sex and coping mechanisms that are likely sources of distinct changes in stress-induced neuroimmune factors and highlight putative sources of exaggerated neuroinflammation in susceptible individuals. Furthermore, we review the current literature of specific neural and glial mechanisms that are regulated by stress and inflammation including mitochondrial function, oxidative stress and mechanisms of glutamate excitotoxicity. Taken together, the impetus for this review is to move towards a better understanding of mechanisms regulated by inflammatory cytokines and chemokines that are capable of contributing to the emergence of depressive-like behaviors in susceptible individuals.

Alcohol enhances type 1 interferon-α production and mortality in young mice infected with Mycobacterium tuberculosis

In the current study, we used a mouse model and human blood samples to determine the effects of chronic alcohol consumption on immune responses during Mycobacterium tuberculosis (Mtb) infection. Alcohol increased the mortality of young mice but not old mice with Mtb infection. CD11b+Ly6G+ cells are the major source of IFN-α in the lungs of Mtb-infected alcohol-fed young mice, and IFN-α enhances macrophage necroptosis in the lungs. Treatment with an anti-IFNAR-1 antibody enhanced the survival of Mtb-infected alcohol-fed young mice. In response to Mtb, peripheral blood mononuclear cells (PBMCs) from alcoholic young healthy individuals with latent tuberculosis infection (LTBI) produced significantly higher amounts of IFN-α than those from non-alcoholic young healthy LTBI+ individuals and alcoholic and non-alcoholic old healthy LTBI+ individuals. Our study demonstrates that alcohol enhances IFN-α production by CD11b+Ly6G+ cells in the lungs of young Mtb-infected mice, which leads to macrophage necroptosis and increased mortality. Our findings also suggest that young alcoholic LTBI+ individuals have a higher risk of developing active TB infection.

Chronic alcohol consumption modulates the host immune defense mechanism(s) and makes the host susceptible to various fungal, viral and bacterial infections, including Mycobacterium tuberculosis (Mtb). However, limited information is available about the mechanisms involved in alcohol-mediated host susceptibility to Mtb and other intracellular bacterial infections. In the current study, we fed control and alcohol diets to young and old mice and determined the mortality rates and the immune mechanisms involved in host susceptibility to Mtb infection. We found that alcohol increases the mortality of young mice but not old mice infected with Mtb. The increased mortality in alcohol-fed Mtb-infected young mice was due to IFN-α production by CD11b+Ly6G+ cells. We also found that PBMCs from young alcoholic individuals with latent tuberculosis infection (LTBI) produced significantly higher amounts of IFN-α than those from young non-alcoholic, old alcoholic and old non-alcoholic LTBI+ individuals. Our findings suggest that young alcoholic LTBI+ individuals have a higher risk of developing active TB infection. Our studies provide the first evidence that chronic alcohol consumption induces IFN-α production in young Mtb-infected mice and increases their mortality rates. Further characterization of CD11b+Ly6G+ cells and delineation of the mechanisms through which alcohol enhances IFN-α production in Ly6G+ cells during Mtb infection will facilitate the development of therapies for alcoholic individuals with latent and active Mtb.

Risk factors for complications and mortality of percutaneous endoscopic gastrostomy insertion

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) is a relatively safe procedure; however, acute and chronic complications of PEG have been reported. We aimed to determine risk factors associated with complications and 30-day mortality after PEG, based on 11 years of experience at a single tertiary hospital.

METHODS

In total, 401 patients who underwent first PEG insertion at the Asan Medical Center, Seoul, Korea, between January 2005 and December 2015 were eligible. Medical records were retrospectively reviewed to determine clinical characteristics and outcomes of 139 and 262 patients who underwent pull-type and introducer-type PEG, respectively.

RESULTS

The median age of the overall population was 68 years, and the median body mass index was 19.5 kg/m2. Acute and chronic complications developed in 96 (23.9%) and 105 (26.2%) patients. Acute ileus and chronic tube obstruction were significantly more frequent in the introducer-type PEG group (p = 0.033 and 0.001, respectively). The 30-day mortality rate was 5.0% (median survival: 10.5 days). Multivariate analysis revealed that underlying malignancy was a predictor of acute complications; age ≥ 70 years and diabetes mellitus were predictors of chronic complications. The median follow-up was 354 days. Neurologic disease and malignancy were the most common indications for PEG. Neurologic diseases were classified into two groups: stroke and the other neurologic disease group (including dementia, Parkinson's disease, neuromuscular disease, and hypoxic brain damage). Multivariate analysis showed that 30-day mortality was significantly lower in the other neurologic disease group and higher in patients with platelet count < 100,000/μL, and C-reactive protein (CRP) ≥ 5 mg/dL.

CONCLUSIONS

PEG is a relatively safe and feasible procedure, but it was associated with significantly higher early mortality rate in patients with platelet count < 100,000/μL or CPR≥5mg/dL, and lower early mortality rate in neurologic disease group including dementia, Parkinson's disase, neuromuscular disease, and hypoxic brain damage. In addition, acute complications in patients with underlying malignancy, and chronic complications in patients aged ≥70 and those with diabetes mellitus should be considered during and after PEG.

The potential of non-myeloablative heterochronous autologous hematopoietic stem cell transplantation for extending a healthy life span

Aging is a complex multifactorial process, a prominent component being the senescence of the immune system. Consequently, immune-related diseases develop, including atherosclerosis, cancer, and life-threatening infections, which impact on health and longevity. Rejuvenating the aged immune system could mitigate these diseases, thereby contributing to longevity and health. Currently, an appealing option for rejuvenating the immune system is heterochronous autologous hematopoietic stem cell transplantation (haHSCT), where healthy autologous bone marrow/peripheral blood stem cells are collected during the youth of an individual, cryopreserved, and re-infused when he or she has reached an older age. After infusion, young hematopoietic stem cells can reconstitute the compromised immune system and improve immune function. Several studies using animal models have achieved substantial extension of the life span of animals treated with haHSCT. Therefore, haHSCT could be regarded as a potential procedure for preventing age-related immune defects and extending healthy longevity. In this review, the pros, cons, and future feasibility of this approach are discussed.

Breaking the Chain of Infection in Older Adults: A Review of Risk Factors and Strategies for Preventing Device-Related Infections

Device-related infections (DRIs) are a significant cause of morbidity and mortality among older adults. Indwelling devices (urinary catheters, percutaneous feeding tubes, and central venous catheters) are frequently used in this vulnerable population. Indwelling devices provide a portal of entry for pathogenic organisms to invade a susceptible host and cause infection and are an important target for infection prevention and antimicrobial stewardship efforts. Within the "Chain of Infection" that leads to DRIs in older adults, multiple opportunities exist to implement interventions that "break the links" and reduce colonization with multidrug-resistant organisms, reduce infections, and improve antimicrobial use.

The Role of Immunosenescence in Neurodegenerative Diseases

Aging is characterized by the progressive decline of physiological function and tissue homeostasis leading to increased vulnerability, degeneration, and death. Aging-related changes of the innate and adaptive immune system include decline in the preservation and enhancement of many immune functions, such as changes in the number of circulating monocytic and dendritic cells, thymic involution, T cell polyfunctionality, or production of proinflammatory cytokines, and are defined as immunosenescence. Inflammatory functions are increased with age, causing the chronic low-grade inflammation, referred to as inflamm-aging, that contribute, together with immunosenescence, to neurodegenerative diseases. In this review, we discuss the link between the immune and nervous systems and how the immunosenescence and inflamm-aging can contribute to neurodegenerative diseases.

The twilight of immunity: emerging concepts in aging of the immune system

Immunosenescence is a series of age-related changes that affect the immune system and, with time, lead to increased vulnerability to infectious diseases. This Review addresses recent developments in the understanding of age-related changes that affect key components of immunity, including the effect of aging on cells of the (mostly adaptive) immune system, on soluble molecules that guide the maintenance and function of the immune system and on lymphoid organs that coordinate both the maintenance of lymphocytes and the initiation of immune responses. I further address the effect of the metagenome and exposome as key modifiers of immune-system aging and discuss a conceptual framework in which age-related changes in immunity might also affect the basic rules by which the immune system operates.

Healthcare-Associated Meningitis or Ventriculitis in Older Adults

BACKGROUND/OBJECTIVES

Healthcare-associated meningitis or ventriculitis (HCAMV) is a serious and life-threatening complication of invasive neurosurgical procedures or penetrating head trauma. Older adults are at higher risk of adverse outcomes in community-acquired meningitis but studies of HCAMV are lacking. Therefore, we perform the study to define the differences in clinical outcomes between older and younger adults with HCAMV.

DESIGN

Retrospective study.

SETTING

A large tertiary care hospital in Houston, Texas, from July 2003 to November 2014.

PARTICIPANTS

Adults with a diagnosis of HCAMV (N = 160) aged ≥65 (n = 35), aged 18-64 (n = 125).

MEASUREMENTS

Demographic characteristics, clinical presentation, laboratory results, treatments, and outcomes (Glasgow Outcome Scale).

RESULTS

Older adults had more comorbidities and CSF abnormalities [pleocytosis, high cerebrospinal fluid (CSF) protein, low CSF glucose) and were more likely to have altered mental status than younger adults (P < .05). An adverse clinical outcome was seen in 142 participants (89%) (death (n = 18, 11%), persistent vegetative state (n = 26, 16%), severe disability (n = 68, 43%), moderate disability (n = 30, 19%). There was no difference in adverse outcomes between older (97%) and younger (86%) adults (P = .13). On logistic regression analysis, abnormal neurological examination (adjusted odds ratio (aOR) = 7.13, 95% confidence interval (CI) = 2.15-23.63, P = .001) and mechanical ventilation (aOR = 11.03, 95% CI = 1.35-90.51, P = .02) were associated with adverse clinical outcomes.

CONCLUSION

Older adults with HCAMV have more comorbidities and CSF abnormalities and are more likely to have altered mental status than younger adults but have similar high rates of adverse clinical outcomes.

Analyzing Nicotinamide Adenine Dinucleotide Phosphate Oxidase Activation in Aging and Vascular Amyloid Pathology

In aging individuals, both protective as well as regulatory immune functions are declining, resulting in an increased susceptibility to infections as well as to autoimmunity. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2-deficiency in immune cell subsets has been shown to be associated with aging. Using intravital marker-free NAD(P)H-fluorescence lifetime imaging, we have previously identified microglia/myeloid cells and astrocytes as main cellular sources of NADPH oxidase (NOX) activity in the CNS during neuroinflammation, due to an overactivation of NOX. The overactivated NOX enzymes catalyze the massive production of the highly reactive O2−, which initiates in a chain reaction the overproduction of diverse reactive oxygen species (ROS). Age-dependent oxidative distress levels in the brain and their cellular sources are not known. Furthermore, it is unclear whether in age-dependent diseases oxidative distress is initiated by overproduction of ROS or by a decrease in antioxidant capacity, subsequently leading to neurodegeneration in the CNS. Here, we compare the activation level of NOX enzymes in the cerebral cortex of young and aged mice as well as in a model of vascular amyloid pathology. Despite the fact that a striking change in the morphology of microglia can be detected between young and aged individuals, we find comparable low-level NOX activation both in young and old mice. In contrast, aged mice with the human APP^E693Q mutation, a model for cerebral amyloid angiopathy (CAA), displayed increased focal NOX overactivation in the brain cortex, especially in tissue areas around the vessels. Despite activated morphology in microglia, NOX overactivation was detected only in a small fraction of these cells, in contrast to other pathologies with overt inflammation as experimental autoimmune encephalomyelitis (EAE) or glioblastoma. Similar to these pathologies, the astrocytes majorly contribute to the NOX overactivation in the brain cortex during CAA. Together, these findings emphasize the role of other cellular sources of activated NOX than phagocytes not only during EAE but also in models of amyloid pathology. Moreover, they may strengthen the hypothesis that microglia/monocytes show a diminished potential for clearance of amyloid beta protein.

Aging and cancer: The role of macrophages and neutrophils

Impaired immune function has been implicated in the declining health and higher incidence of cancer in the elderly. However, age-related changes to immunity are not completely understood. Neutrophils and macrophages represent the first line of defence yet their ability to phagocytose pathogens decrease with aging. Cytotoxic T lymphocytes are critical in eliminating tumors, but T cell function is also compromised with aging. T cell responses can be regulated by macrophages and may depend on the functional phenotype macrophages adopt in response to microenvironmental signals. This can range from pro-inflammatory, anti-tumorigenic M1 to anti-inflammatory, pro-tumorigenic M2 macrophages. Macrophages in healthy elderly adipose and hepatic tissue exhibit a more pro-inflammatory M1 phenotype compared to young hosts whilst immunosuppressive M2 macrophages increase in elderly lymphoid tissues, lung and muscle. These M2-like macrophages demonstrate altered responses to stimuli. Recent studies suggest that neutrophils also regulate T cell function and, like macrophages, neutrophil function is modulated with aging. It is possible that age-modified tissue-specific macrophages and neutrophils contribute to chronic low-grade inflammation that is associated with dysregulated macrophage-mediated immunosuppression, which together are responsible for development of multiple pathologies, including cancer. This review discusses recent advances in macrophage and neutrophil biology in healthy aging and cancer.

Incidence and Risk Factors for Major Surgical Site Infections in Aesthetic Surgery: Analysis of 129,007 Patients

BACKGROUND

Surgical site infections (SSIs) represent one of the most common postoperative complications in patients undergoing aesthetic surgery.

OBJECTIVES

This study reports the incidence and risk factors of major SSIs following aesthetic surgery.

METHODS

A prospective cohort of patients who underwent aesthetic surgery between 2008 and 2013 was identified from the CosmetAssure database. Primary outcome was occurrence of a major SSI requiring emergency room visit, hospital admission, or reoperation within 30 days of the index operation. Univariate and multivariate analysis evaluated potential risk factors for SSIs including age, gender, body mass index (BMI), smoking, diabetes, type of surgical facility, procedure by body region, and combined procedures.

RESULTS

A total of 129,007 patients were identified, of which 599 (0.46%) had a major SSI. Mean age (43.8 ± 12.4 years vs 40.9 ± 13.9 years, P < .01) and BMI (27.3 ± 5.5 kg/m² vs 24.3 ± 4.6 kg/m², P < .01) were higher in patients with SSIs. Patients with a SSI were more likely to be smokers (10.5% vs 8.2%, P = .04) and diabetic (4.5% vs 1.8%, P < .01). Females suffered more SSI than males (0.5% vs 0.3%, P = .02). Trunk/extremity procedures had a higher incidence of SSI compared to breast or face procedures (0.9% vs 0.2%, P < .01). On multivariate analysis, independent predictors of SSI included age (Relative Risk [RR] 1.01), female gender (RR 1.86), BMI (RR 1.07), smoking (RR 1.61), diabetes (RR 1.58), hospital or ambulatory surgery center procedures (RR 1.39), trunk/extremity procedures (RR 2.42), and combined procedures (RR 1.88).

CONCLUSIONS

SSIs following cosmetic surgical procedures are associated with numerous independent predictors, which should be taken into consideration when counseling patients undergoing aesthetic surgery.

LEVEL OF EVIDENCE

2 Risk.

Immune Dysfunction in Aged Horses

The aging process in people is associated with changes in adaptive and innate immune responses. Similar changes occur in aged horses. Age-related progressive impairment in the ability to respond to pathogen challenge and an increased inflammatory reactivity may predispose geriatric horses to many diseases of old age. Specific recommendations for immune modification of older horses, including an age-appropriate vaccination schedule, are not currently available. In addition, the effect of old age on risk of infectious disease is poorly documented. More work is needed to better understand the interactions of age on immunity, vaccine response, and disease risk in horses.

Altered Innate Immune Responses in Neutrophils from Patients with Well- and Suboptimally Controlled Asthma

BACKGROUND

Respiratory infections are a major cause of asthma exacerbations where neutrophilic inflammation dominates and is associated with steroid refractory asthma. Structural airway cells in asthma differ from nonasthmatics; however it is unknown if neutrophils differ. We investigated neutrophil immune responses in patients who have good (AGood) and suboptimal (ASubopt) asthma symptom control.

METHODS

Peripheral blood neutrophils from AGood (ACQ < 0.75, n = 11), ASubopt (ACQ > 0.75, n = 7), and healthy controls (HC) (n = 9) were stimulated with bacterial (LPS (1 μg/mL), fMLF (100 nM)), and viral (imiquimod (3 μg/mL), R848 (1.5 μg/mL), and poly I:C (10 μg/mL)) surrogates or live rhinovirus (RV) 16 (MOI1). Cell-free supernatant was collected after 1 h for neutrophil elastase (NE) and matrix metalloproteinase- (MMP-) 9 measurements or after 24 h for CXCL8 release. Results. Constitutive NE was enhanced in AGood neutrophils compared to HC. fMLF stimulated neutrophils from ASubopt but not AGood produced 50% of HC levels. fMLF induced MMP-9 was impaired in ASubopt and AGood compared to HC. fMLF stimulated CXCL8 but not MMP-9 was positively correlated with FEV1 and FEV1/FVC. ASubopt and AGood responded similarly to other stimuli.

CONCLUSIONS

Circulating neutrophils are different in asthma; however, this is likely to be related to airflow limitation rather than asthma control.

Flagellin-dependent TLR5/caveolin-1 as a promising immune activator in immunosenescence

The age-associated decline of immune responses causes high susceptibility to infections and reduced vaccine efficacy in the elderly. However, the mechanisms underlying age-related deficits are unclear. Here, we found that the expression and signaling of flagellin (FlaB)-dependent Toll-like receptor 5 (TLR5), unlike the other TLRs, were well maintained in old macrophages, similar to young macrophages. The expression and activation of TLR5/MyD88, but not TLR4, were sensitively regulated by the upregulation of caveolin-1 in old macrophages through direct interaction. This interaction was also confirmed using macrophages from caveolin-1 or MyD88 knockout mice. Because TLR5 and caveolin-1 were well expressed in major old tissues including lung, skin, intestine, and spleen, we analyzed in vivo immune responses via a vaccine platform with FlaB as a mucosal adjuvant for the pneumococcal surface protein A (PspA) against Streptococcus pneumoniae infection in young and aged mice. The FlaB-PspA fusion protein induced a significantly higher level of PspA-specific IgG and IgA responses and demonstrated a high protective efficacy against a lethal challenge with live S. pneumoniae in aged mice. These results suggest that caveolin-1/TLR5 signaling plays a key role in age-associated innate immune responses and that FlaB-PspA stimulation of TLR5 may be a new strategy for a mucosal vaccine adjuvant against pneumococcal infection in the elderly.

Reduced bioenergetics and toll-like receptor 1 function in human polymorphonuclear leukocytes in aging

Aging is associated with a progressive decline in immune function (immunosenescence) resulting in an increased susceptibility to viral and bacterial infections. Here we show reduced expression of Toll-like receptor 1 (TLR1) in polymorphonuclear leukocytes (PMN) and an underlying age-dependent deficiency in PMN bioenergetics. In older (>65 years) adults, stimulation through TLR1 led to lower activation of integrins (CD11b and CD18), lower production of the chemokine IL-8, and lower levels of the phosphorylated signaling intermediate p38 MAP kinase than in PMN from younger donors (21-30 years). In addition, loss of CD62L, a marker of PMN activation, was reduced in PMN of older adults stimulated through multiple pathways. Rescue of PMN from apoptosis by stimulation with TLR1 was reduced in PMN from older adults. In seeking an explanation for effects of aging across multiple pathways, we examined PMN energy utilization and found that glucose uptake after stimulation through TLR1 was dramatically lower in PMN of older adults. Our results demonstrate a reduction in TLR1 expression and TLR1-mediated responses in PMN with aging, and reduced efficiency of bioenergetics in PMN. These changes likely contribute to reduced PMN efficiency in aging through multiple aspects of PMN function and suggest potential therapeutic opportunities.

Regulation of hematopoietic stem cell aging by the small RhoGTPase Cdc42

Aging of stem cells might be the underlying cause of tissue aging in tissue that in the adult heavily rely on stem cell activity, like the blood forming system. Hematopoiesis, the generation of blood forming cells, is sustained by hematopoietic stem cells. In this review article, we introduce the canonical set of phenotypes associated with aged HSCs, focus on the novel aging-associated phenotype apolarity caused by elevated activity of the small RhoGTPase in aged HSCs, discuss the role of Cdc42 in hematopoiesis and describe that pharmacological inhibition of Cdc42 activity in aged HSCs results in functionally young and thus rejuvenated HSCs.

Age-associated aberrations in mouse cellular and humoral immune responses

BACKGROUND AND AIMS

Several contradictions and inconsistent reports regarding nature of dysfunction of immune system with age are known. The lack of multipoint age comparisons in immune functions contributes to the observed ambiguity in understanding immunosenescence. Thus, the present study aimed at a concurrent analysis of different immune cells in an attempt to delineate the nature of dysregulation with progressive aging in mice.

METHODS

4, 8, 12 and 16 months old mice were analyzed for various immune parameters involving neutrophils, peripheral blood lymphocytes, peritoneal macrophages, splenocytes, inflamm-aging markers in plasma and humoral immune response in intestine.

RESULTS

Neutrophils registered a remarkable decrease in activities of respiratory burst enzymes and phagocytosis, while macrophages recorded a decrease in TLR-2 and TLR-4 expression. MCP-1 and CRP levels increased in plasma, whereas stimulation index and CD28 expression decreased in lymphocytes. Interleukins analysis (IFN-γ, IL-4, IL-10) showed a remarkable shift towards Th2 response which further resulted in increased IgG1/IgG2a ratio and IgE levels in intestine.

CONCLUSION

A decline in cell-mediated immune response, chronic inflammation and aggravation of humoral immunity was evident which conclusively suggests a skewed Th2 pathway during aging.

Improvement in Th1/Th2 immune homeostasis, antioxidative status and resistance to pathogenic E. coli on consumption of probiotic Lactobacillus rhamnosus fermented milk in aging mice

Imbalance in Th1/Th2 immune pathways and cellular antioxidant systems with progressive aging are among the leading causes of increased risk of morbidity and mortality in elderly. Although probiotics have been considered to boost immune system, there is a lack of comprehensive analysis of probiotic effects on aging physiology. The present study aimed at determining anti-immunosenescence potential of milk fermented with probiotic Lactobacillus rhamnosus (LR) in 16 months old mice by concurrent analysis of immunosenescence markers associated with Th1/Th2 profile of splenocytes, inflamm-aging in plasma, neutrophil functions and antibody response in intestine along with analysis of antioxidant enzymes in liver and red blood cells (RBCs) after feeding trials of 1 and 2 months, respectively. An enteropathogenic Escherichia coli (ATCC 14948)-based infection model in aging mice was also designed to validate protective attributes of LR. Splenocytes registered increased IFN-γ and decreased IL-4 and IL-10 production in LR-fed animals. Neutrophil respiratory burst enzymes and phagocytosis increased significantly while no aggravation in plasma levels of MCP-1 and TNF-α was observed. Further, owing to increased Th1 response, antibodies registered a decrease in IgG1/IgG2a ratio and IgE levels in LR groups. No significant variations were observed in secretory IgA and IgA + cells in the intestine. Antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) in LR-fed groups recorded increased activities which were more pronounced in the liver than in RBCs. LR supplementation significantly reduced E. coli translocation to organs (intestine, liver, spleen, peritoneal fluid) by enhancing E. coli-specific antibodies (IgA and IgG1) and inflammatory proteins. In conclusion, LR supplementation alleviated immunosenescence-associated Th1/Th2 imbalance, improved antioxidant capacity, and enhanced resistance of aged mice to E. coli infection thereby signifying its potential in augmenting healthy aging.

Old age is associated with increased severity of complications in endoscopic biliary stone removal

BACKGROUND AND AIM

Various techniques are required in endoscopic biliary stone removal. Because the presence of biliary stones is a benign disease, it is essential to minimize procedure-related complications. Having a sound knowledge of the risk factors can help reduce the number and severity of complications. We determined the risk factors for complications in patients undergoing endoscopic biliary stone removal.

METHODS

This was a retrospective observational cohort study. We analyzed 743 consecutive patients with biliary stones who were treated with endoscopic retrograde cholangiopancreatography and identified the independent risk factors for complications.

RESULTS

Complications occurred in 66 patients (8.9%). Pancreatitis occurred in 26 patients (3.5%), cholangitis in 16 (2.2%), bleeding in 12 (1.6%) and other in 12 (1.6%). Independent risk factors for overall complications were multiple biliary stones (P = 0.0480) and anti-thrombotic drugs (P = 0.0186).Independent risk factors for moderate or severe complications were old age (P = 0.0201), multiple biliary stones (P = 0.0300), anti-thrombotic drugs (P = 0.0131), and cirrhosis of the liver (P = 0.0013). The respective risk factors for pancreatitis, cholangitis, and bleeding were precut technique (P = 0.0005), endoscopic mechanical lithotripsy (P = 0.0421), and both anti-thrombotic drugs (P = 0.0228) and cirrhosis of the liver (P = 0.0115).

CONCLUSIONS

Old age was associated with a similar complication rate to younger age but increased the severity of complications following endoscopic biliary stone removal. Improved awareness of the severity of complications may be of benefit during periprocedural management. Further studies are warranted.