Increased frequency of CD14+HLA-DR-/low cells in type 2 diabetes patients with poor glycemic control.

AIMS: Type 2 diabetes (T2DM) is associated with alterations of the immune response and T2DM patients have an increased risk for infections and certain sorts of cancers. Although CD14+HLA-DR-/low cells have emerged as important mediators of immunosuppression in several pathologies, including cancer and non-malignant diseases, the presence of these cells in T2DM is not fully characterized. METHODS: In this study, we evaluated the frequency of CD14+HLA-DR-/low cells in non-obese T2DM patients and their association with glycemic control. Peripheral blood mononuclear cells were isolated from healthy controls (HC, n = 24) and non-obese T2DM patients (n = 25), the population was evaluated by flow cytometry, and an analysis of correlation between cell frequencies and clinical variables was performed. RESULTS: CD14+HLA-DR-/low monocytes were expanded in patients with T2DM compared to HC regardless of weight. Among the subjects with T2DM, the frequency of CD14+HLA-DR-/low was higher in patients with poor glycemic control (HbA1c > 9%) compared to those with better glycemic control (HbA1c < 9%) and, positively correlated with the years since the diagnosis of T2DM, the age of the patients and the glycemic index. CONCLUSIONS: An increased frequency of CD14+HLA-DR-/low cells in the blood of T2DM patients was recorded. The influence of hyperglycemia seems to be independent of obesity, but related to glycemic control and age.

Antimicrobial peptides in domestic animals and their applications in veterinary medicine.

Antimicrobial peptides (AMPs) are molecules with a broad-spectrum activity against bacteria, fungi, protozoa, and viruses. These peptides are widely distributed in insects, amphibians and mammals. Indeed, they are key molecules of the innate immune system with remarkable antimicrobial and immunomodulatory activity. Besides, these peptides have also shown regulatory activity for gut microbiota and have been considered inductors of growth performance. The current review describes the updated findings of antimicrobial peptides in domestic animals, such as bovines, goats, sheep, pigs, horses, canines and felines, analyzing the most relevant aspects of their use as potential therapeutics and their applications in Veterinary medicine.

Type 2 diabetes mellitus metabolic control correlates with the phenotype of human monocytes and monocyte-derived macrophages.

AIMS: Monocytes and macrophages express cell-surface markers indicative of their inflammatory and activation status. In this study, we investigated whether these markers are affected or correlated in non-obese T2D subjects, or glycemic/metabolic control variables. METHODS: Clinical data was recorded, and peripheral blood drawn from T2D patients (n = 28) and control subjects (n = 27). Isolated monocytes were evaluated by flow cytometry for the expression of CD14, CD16, and the phenotypic markers for the different states of activation spectrum, such as pro-inflammatory (M1) (HLA-DR, CD86), anti-inflammatory/pro-resolving (M2) (CD163, CD206, MERTK, PD-L1) and metabolically-activated (MMe) (CD36, ABCA-1). From a subset of individuals, monocytes-derived macrophages (MDM) were obtained and evaluated for phenotypic markers. A correlation analysis was performed between the clinical variables and the marker expression. RESULTS: The frequency of CD14++CD16- monocytes was lower in T2D patients and it correlates negatively with poor control in glycemic and metabolic variables. T2D monocytes expressed lower levels of HLA-DR, CD86, PD-L1, and CD163, which correlated negatively with poor metabolic control. In MDM from T2D patients, HLA-DR, CD86 and CD163 expression was lower and it inversely correlated with deficient glycemic or metabolic control parameters. CONCLUSION: The glycemic/metabolic control associated with T2D influences monocyte and MDM phenotypes toward an immune-suppressive phenotype.

Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis.

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

Production of antimicrobial peptides is preserved in aging.

There is an increased susceptibility to infections during elderly, mainly because of the decreased efficacy of adaptive immunity to contain microorganisms. Albeit most of the elderly adults develop this deficiency in adaptive immunity only a minor percentage of them developed recurrent infectious diseases, thus innate immunity represents an important barrier to avoid infections in this group of aged people. Since antimicrobial peptides are important molecules of innate immunity in the study we sought to determine whether healthy aging correlates with a proper antimicrobial production. Our results by ELISA and flow cytometry showed that healthy elder individuals produce significant amounts of both cathelicidin and ß-defensin-2 (hBD-2) comparable with those found in healthy young individuals. Our results suggest that during healthy aging the maintenance of the antimicrobial peptide innate immune response may be responsible for the protection against infectious diseases.

Induction of ß-defensins by l-isoleucine as novel immunotherapy in experimental murine tuberculosis.

Tuberculosis is a worldwide health problem, and multidrug-resistant (MDR) and extensively multidrug-resistant (XMDR) strains are rapidly emerging and threatening the control of this disease. These problems motivate the search for new treatment strategies. One potential strategy is immunotherapy using cationic anti-microbial peptides. The capacity of l-isoleucine to induce beta-defensin expression and its potential therapeutic efficiency were studied in a mouse model of progressive pulmonary tuberculosis. BALB/c mice were infected with Mycobacterium tuberculosis strain H37Rv or with a MDR clinical isolate by the intratracheal route. After 60 days of infection, when disease was in its progressive phase, mice were treated with 250 µg of intratracheal l-isoleucine every 48 h. Bacillary loads were determined by colony-forming units, protein and cytokine gene expression were determined by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), respectively, and tissue damage was quantified by automated morphometry. Administration of l-isoleucine induced a significant increase of beta-defensins 3 and 4 which was associated with decreased bacillary loads and tissue damage. This was seen in animals infected with the antibiotic-sensitive strain H37Rv and with the MDR clinical isolate. Thus, induction of beta-defensins might be a potential therapy that can aid in the control of this significant infectious disease.

Kinetics and cellular sources of cathelicidin during the course of experimental latent tuberculous infection and progressive pulmonary tuberculosis.

In spite of advances in immunology on mycobacterial infection, there are few studies on the role of anti-microbial peptides in tuberculosis. The cathelin-related anti-microbial peptide (CRAMP) is the only cathelicidin isolated from mice. In this work we investigated the cellular sources and the production kinetics of this molecule during experimental tuberculosis, using two well-characterized models of latent or chronic infection and progressive disease. The lung of non-infected control mice expressed CRAMP at very low levels. In both models of experimental tuberculosis the main cells immunolabelled for CRAMP were bronchial epithelial cells, macrophages and pneumocytes types II and I. After intratracheal infection with a high bacilli dose (H37Rv strain) in Balb/c mice to produce progressive disease, a high CRAMP gene expression was induced showing three peaks: very early after 1 day of infection, at day 21 when the peak of protective immunity in this model is raised, and at day 28 when the progressive phase starts and the immunoelectronmicroscopy study showed intense immunolabelling in the cell wall and cytoplasm of intracellular bacilli, as well as in cytoplasmic vacuoles. Interestingly, at day 60 post-infection, when advanced progressive disease is well established, characterized by high bacillary loads and extensive tissue damage, CRAMP gene expression decreased but strong CRAMP immunostaining was detected in vacuolated macrophages filled with bacilli. Thus, cathelicidin is highly produced during experimental pulmonary tuberculosis from diverse cellular sources and could have significant participation in its pathogenesis.

[Nicotine as an antidepressant and regulator of sleep in subjects with depression]. / Acción de la nicotina como antidepresivo y regulador del sueño en sujetos deprimidos.

INTRODUCTION: Depression is a chronic and heterogeneous disorder manifesting itself by mood and sleep irregularities which ultimately can lead to suicide. Depressed individuals have a higher tendency to smoking compared to non-depressed people, and the interruption of this dependence produces even more depression. This situation may be reverted by the administration of anti-depressives and/or the use of nicotine replacement therapies. Taking into account these observations it will be explained how nicotine possibly acts in relation to two main neurotransmitters: serotonin and dopamine; and as a neuroprotective agent under a depressive condition. The effect of nicotine as a sleep regulator in depressed subjects will also be presented. AIM. To describe and discuss the evidences showing that nicotine has anti-depressive properties. DEVELOPMENT: In order of finding are presented in the following pages evidences showing that nicotine therapeutically can be used as an anti-depressive agent: general aspects of nicotine action (pharmacology, metabolism, nicotinic receptors), general features of depression, nicotine interactions in depressive disorders, and nicotine and the regulation of sleep. CONCLUSIONS: Even though the basis of the relationship 'nicotine-depression' is not clear, the suggested anti-depressive role of nicotine involves a direct action over dopaminergic and serotoninergic activity or a possible indirect action as a neuroprotective agent, events which may have therapeutic effects on the quality of sleep and enhancement of depressive symptoms.

Acción de la nicotina como antidepresivo y regulador del sueño en sujetos deprimidos / Nicotine as an antidepressant and regulator of sleep in subjects with depression

Resumen. Introducción. La depresión es un trastorno heterogéneo crónico que se manifiesta por irregularidades en el humor y sueño que pueden llevar al suicidio. Individuos deprimidos tienden a fumar más que los no deprimidos y la interrupción de este hábito produce una depresión mayor que se revierte con el uso de antidepresivos o terapias de reemplazo de nicotina. Basándonos en estos hallazgos, explicaremos cómo actúa posiblemente la nicotina sobre dos neurotransmisores principales (serotonina y dopamina), y como neuroprotector en procesos depresivos, además de exponer el efecto de la nicotina como regulador de sueño en sujetos deprimidos. Objetivo. Describir y discutir las evidencias que han demostrado que la nicotina tiene propiedades antidepresivas. Desarrollo. Se presenta el orden de los hallazgos que demuestran que la nicotina puede utilizarse como antidepresivo: aspectos generales de la nicotina (farmacología, metabolismo y receptores nicotínicos), características generales de la depresión, mecanismo de interacción de la nicotina en los trastornos depresivos, y nicotina y regulación del sueño. Conclusiones. A pesar de que la base neurobiológica de esta asociación ‘nicotina-depresión’ no es clara, el mecanismo antidepresivo sugerido para la nicotina involucra su acción directa sobre la actividad dopaminérgica y serotoninérgica o su posible acción indirecta como neuroprotector, lo que origina efectos terapéuticos sobre la calidad de sueño y mejora de los síntomas depresivos (AU)

Summary. Introduction. Depression is a chronic and heterogeneous disorder manifesting itself by mood and sleep irregularities which ultimately can lead to suicide. Depressed individuals have a higher tendency to smoking compared to non-depressed people, and the interruption of this dependence produces even more depression. This situation may be reverted by the administration of anti-depressives and/or the use of nicotine replacement therapies. Taking into account these observations it will be explained how nicotine possibly acts in relation to two main neurotransmitters: serotonin and dopamine; and as a neuroprotective agent under a depressive condition. The effect of nicotine as a sleep regulator in depressed subjects will also be presented. Aim. To describe and discuss the evidences showing that nicotine has anti-depressive properties. Development. In order of finding are presented in the following pages evidences showing that nicotine therapeutically can be used as an antidepressive agent: general aspects of nicotine action (pharmacology, metabolism, nicotinic receptors), general features of depression, nicotine interactions in depressive disorders, and nicotine and the regulation of sleep. Conclusions. Even though the basis of the relationship ‘nicotine-depression’ is not clear, the suggested anti-depressive role of nicotine involves a direct action over dopaminergic and serotoninergic activity or a possible indirect action as a neuroprotective agent, events which may have therapeutic effects on the quality of sleep and enhancement of depressive symptoms (AU)

Mycobacterium tuberculosis entry into mast cells through cholesterol-rich membrane microdomains.

Cholesterol-enriched membrane microdomains (lipid rafts) play a role in the uptake of many pathogens. Mycobacteria are one of the intracellular pathogens that utilize lipid rafts in order to invade both phagocytic and non-phagocytic cells. However, the mechanism of Mycobacterium tuberculosis uptake by mast cell is not known. To address this issue, we investigated the interaction of M. tuberculosis (H37Rv strain) with mast cells. Confocal microscopy showed that interaction of mycobacterium with mast cell resulted in changes in the mast cell surface, with formation of pseudopod-like structure and activation with visibly extruded granules. Moreover, infection of mast cells with Mycobacteria induced cholesterol accumulation at the site of bacterial entry and around intracellular mycobacteria. Disruption of mast cells lipid rafts by cholesterol depletion markedly inhibited the mycobacterium entry. Intracellular multiplication of M. tuberculosis within mast cells was also observed. Overall, our results indicate that M. tuberculosis employs a cholesterol-dependent pathway to infect mast cells, which leads to degranulation and mast cell morphological changes. These results suggest that although mast cells are capable to respond to M. tuberculosis infection, entry of mycobacterium through lipid rafts may allow replication within mast cells.

The potential role of lung epithelial cells and beta-defensins in experimental latent tuberculosis.

Mycobacterium tuberculosis is a facultative intracellular pathogen capable of producing both progressive disease and latent infection. Latent infection is clinically asymptomatic and is manifested only by a positive tuberculin test or a chest radiograph that shows scars or calcified nodules indicative of resolved primary tuberculosis infection. In this study, we used a well-characterized model of latent tuberculosis infection in B6D2F1 mice to compare the production of beta-defensin-3 by infected bronchial epithelial cells and macrophages. We demonstrated by immunolectronmicroscopy that M. tuberculosis can actually infect epithelial cells and induce significant higher production of beta-defensin-3 associated to mycobacteria than infected macrophages. These results demonstrate that lung epithelium harbour mycobacteria during experimental chronic infection; being a possible reservoir of latent mycobacteria in vivo, beta-defensins might participate in bacilli killing or dormancy induction.