Tuberculous Granuloma Formation Research Articles

HIV-MTB Co-Infection Reduces CD4+ T Cells and Affects Granuloma Integrity.

Granuloma is a crucial pathological feature of tuberculosis (TB). The relationship between CD4+ T cells in both peripheral blood and granulomatous tissue, and the integrity of granulomas in Human Immunodeficiency Virus (HIV)-MTB co-infection, remains unexplored. This study collected biopsy specimens from 102 TB patients (53 with HIV-MTB co-infection and 49 only with TB). Hematoxylin and eosin (HE) staining and immunohistochemical staining were performed, followed by microscopic examination of the integrity of tuberculous granulomas. Through statistical analysis of peripheral blood CD4+ T cell counts, tissue CD4+ T cell proportion, and the integrity of granulomas, it was observed that HIV infection leads to poor formation of tuberculous granulomas. Peripheral blood CD4+ T cell counts were positively correlated with granuloma integrity, and there was a similar positive correlation between tissue CD4+ T cell proportions and granuloma integrity. Additionally, a positive correlation was found between peripheral blood CD4+ T cell counts and the proportion of CD4+ T cells in granuloma tissues. Therefore, HIV infection could impact the morphology and structure of tuberculous granulomas, with a reduced proportion of both peripheral blood and tissue CD4+ T lymphocytes.

RAPID GROWTH OF GRANULATION TISSUE: A RARE CAUSE OF STRIDOR

RAPID GROWTH OF GRANULATION TISSUE: A RARE CAUSE OF STRIDOR

Restricted Activation of the NF-κB Pathway in Individuals with Latent Tuberculosis Infection after HIF-1α Blockade.

Tuberculous granuloma formation is mediated by hypoxia-inducible factor 1 alpha (HIF-1α), and is essential for establishing latent tuberculosis infection (LTBI) and its progression to active tuberculosis (TB). Here, we investigated whether HIF-1α expression and adjacent mechanisms were associated with latent or active TB infection. Patients with active TB, individuals with LTBI, and healthy controls were recruited, and the expression of cytokine genes IL15, IL18, TNFA, IL6, HIF1A, and A20 in peripheral blood mononuclear cells (PBMCs) and serum vitamin D (25(OH)D3) levels were evaluated. Additionally, nuclear factor kappa B (NF-κB) and tumor necrosis factor-alpha (TNF-α) levels were analyzed in PBMC lysates and culture supernatants, respectively, after HIF-1α blockade with 2-methoxyestradiol. We observed that IL-15 expression was higher in individuals with LTBI than in patients with active TB, while IL-18 and TNF-α expression was similar between LTBI and TB groups. Additionally, serum 25(OH)D3 levels and expression of IL-6, HIF1A, and A20 were higher in patients with active TB than in individuals with LTBI. Moreover, PBMCs from individuals with LTBI showed decreased NF-κB phosphorylation and increased TNF-α production after HIF-1α blockade. Together, these results suggest that under hypoxic conditions, TNF-α production and NF-κB pathway downregulation are associated with the LTBI phenotype.

Tuberculous Granuloma: Emerging Insights From Proteomics and Metabolomics.

Mycobacterium tuberculosis infection, which claims hundreds of thousands of lives each year, is typically characterized by the formation of tuberculous granulomas — the histopathological hallmark of tuberculosis (TB). Our knowledge of granulomas, which comprise a biologically diverse body of pro- and anti-inflammatory cells from the host immune responses, is based mainly upon examination of lungs, in both human and animal studies, but little on their counterparts from other organs of the TB patient such as the brain. The biological heterogeneity of TB granulomas has led to their diverse, relatively uncoordinated, categorization, which is summarized here. However, there is a pressing need to elucidate more fully the phenotype of the granulomas from infected patients. Newly emerging studies at the protein (proteomics) and metabolite (metabolomics) levels have the potential to achieve this. In this review we summarize the diverse nature of TB granulomas based upon the literature, and amplify these accounts by reporting on the relatively few, emerging proteomics and metabolomics studies on TB granulomas. Metabolites (for example, trimethylamine-oxide) and proteins (such as the peptide PKAp) associated with TB granulomas, and knowledge of their localizations, help us to understand the resultant phenotype. Nevertheless, more multidisciplinary ‘omics studies, especially in human subjects, are required to contribute toward ushering in a new era of understanding of TB granulomas – both at the site of infection, and on a systemic level.

Dynamics of signs of granulomatous inflammation of the liver after administration of the BCG vaccine in mice of different ages

Purpose of the study. The aim of the study was to study the morphogenesis of granulomatous inflammation in the liver in newborn animals and in remote periods of life.Materials and methods. The experiment was carried out on 70 newborn C57BL / 6 mice, divided into two groups. On the first day after birth, mice of the 1st (experimental) group were injected intraperitoneally with a solution of the BCG vaccine at a dose of 0.02 mg / kg. On the fi rst day of the beginning of the experiment, the mice of the 2nd (control) group were injected intraperitoneally with 0.02 ml of physiological solution. Liver samples were subjected to morphological and morphometric study: the body weight of mice (g), the volumetric density (Vv) of dystrophy and necrosis of hepatocytes, foci of extramedullary hematopoiesis, the number density (Nai) of binuclear hepatocytes, mitotic figures, the diameter of granulomas (μm), and the number density were calculated (Nai) granulomas in test area.Results. The introduction of the BCG vaccine to newborn mice on the 1st day led to a delay in their development and a lack of body weight. With the introduction of the BCG vaccine to newborn mice of the C57B1 / 6 line, a delayed formation of granulomas is noted, starting from the 10th day after the administration of the BCG vaccine, and a subsequent increase by 56 days in both the number and size of granulomas. The foci of extramedullary hematopoiesis in the liver of mice after the administration of the BCG vaccine persist for a longer period (up to 28 days), which is probably due to the participation of cells of the foci of hematopoiesis in the inflammatory process in the liver parenchyma. With the introduction of the BCG vaccine, pronounced destructive changes in hepatocytes in mice at all age periods are noted with reduced rates of reparative liver regeneration. Conclusion. The introduction of BCG vaccine to newborn mice led to the formation of tuberculous granulomas in the liver during the adult period of life with the development of destructive changes in hepatocytes and a reduced reparative ability of the liver.

A non-canonical type 2 immune response coordinates tuberculous granuloma formation and epithelialization

The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.

Histological and Epidemiological study on Mycobacterium tuberculosis in Nineveh Governorate

Tuberculosis (TB) is a common infection especially in developing countries and can involve almost all bodily systems. Iraq has been identified as middle TB burden country in the world. The aims of the study are to determine the main factors that lead to prevalence of TB in people living in Nineveh governorate, to study the histopathological effect of M. tuberculosis on the tissues. The objective of epidemiological study is to find the relationship between M. tuberculosis and age, sex, education level, occupation, type of TB and sectors of people living in Nineveh governorate. This study included 100 patients infected with Mycobacterium tuberculosis ( 51 males and 49 females ) the age of the patients ranged from 1–75 years through the period from september 2010 to september 2011. In order to determine the main factors that lead to TB infection, data collected from all 100 patients infected with TB. Tissue sections were taken from patients with active TB from (lung, lymph node and breast mass) and fixed in (10%) formaldehyde and (4µm) paraffin blocks sections stained with hematoxylin and eosin or Ziehl Neelsen stain for histopathological examination. Data for epidemiological study of patients diagnosed with TB were collected from consultant clinic for chest and respiratory diseases in Nineveh governorate over a 16-year period (1994-2010). The results showed that The main factors that lead to TB infection were diabetes with a percentage of (25%) of the patients, followed by smoking with a percentage of (20%) . Changes in the tissues infected with tuberculosis is the formation of tuberculous granulomas .The result of epidemiological study showed that the number of Tuberculosis cases in Nineveh governorate increased between 1994-2002 and decreased between 2002-2010. The number of TB cases in males is more than in females . The main age groups infected with TB was the productive ages (15-34 years). Pulmonary TB is more than Extrapulmonary TB .The highest percentage of TB in sectors of Nineveh governorate (25%) for each of left sector and right sector, followed by (13.7%) in Sinjar.

Pathomorphological peculiarities of tuberculous meningoencephalitis associated with HIV infection.

Background and aimsOne of the most severe manifestation displays of tuberculosis (TB) generalization is meningitis/meningoencephalitis. The purpose of this work was to improve the diagnostic efficiency of TB central nervous system (CNS) affection in human immunodeficiency virus (HIV)-infected persons.Materials and methodsMeninges and cerebral tissues, taken from died patients, who were HIV-infected and dead from TB of CNS affection, were investigated histologically.Results and discussionOur examination showed that clinical course of the pathologic process loses the peculiarity of TB-undulating character, and changes in tissues have monomorphism that appears in the presence of the same type of granulomas with a few Pirogov–Langhans cells. Alterative reactions with formation of the large fields of caseous necrosis, necrotic focuses, areas of infiltration with polymorphic cellular elements went out on the first plan in the disorder of cerebrum in patients with the terminal stage of HIV infection. The tendency to decrease in inflammatory–proliferative processes was observed, which is confirmed by the presence of the poorly expressed cellular reaction on the peripheries of focuses of caseous necrosis.ConclusionMorphologic features of tuberculous meningoencephalitis in HIV-infected patients are the presence of edema, gliosis, trombovasculitis, small focal hemorrhage, tuberculous granuloma formation with a small number of Pirogov–Langhans cells, and the prevalence of alterative–exudative reactions.

Mycobacterium tuberculosis-Induced Polarization of Human Macrophage Orchestrates the Formation and Development of Tuberculous Granulomas In Vitro.

The tuberculous granuloma is an elaborately organized structure and one of the main histological hallmarks of tuberculosis. Macrophages, which are important immunologic effector and antigen-presenting cells, are the main cell type found in the tuberculous granuloma and have high plasticity. Macrophage polarization during bacterial infection has been elucidated in numerous recent studies; however, macrophage polarization during tuberculous granuloma formation and development has rarely been reported. It remains to be clarified whether differences in the activation status of macrophages affect granuloma formation. In this study, the variation in macrophage polarization during the formation and development of tuberculous granulomas was investigated in both sections of lung tissues from tuberculosis patients and an in vitro tuberculous granuloma model. The roles of macrophage polarization in this process were also investigated. Mycobacterium tuberculosis (M. tuberculosis) infection was found to induce monocyte-derived macrophage polarization. In the in vitro tuberculous granuloma model, macrophage transformation from M1 to M2 was observed over time following M. tuberculosis infection. M2 macrophages were found to predominate in both necrotic and non-necrotic granulomas from tuberculosis patients, while both M1 and M2 polarized macrophages were found in the non-granulomatous lung tissues. Furthermore, it was found that M1 macrophages promote granuloma formation and macrophage bactericidal activity in vitro, while M2 macrophages inhibit these effects. The findings of this study provide insights into the mechanism by which M. tuberculosis circumvents the host immune system as well as a theoretical foundation for the development of novel tuberculosis therapies based on reprogramming macrophage polarization.

An In Vivo Platform for Rapid High-Throughput Antitubercular Drug Discovery

Treatment of tuberculosis, like other infectious diseases, is increasingly hindered by the emergence of drug resistance. Drug discovery efforts would be facilitated by facile screening tools that incorporate the complexities of human disease. Mycobacterium marinum-infected zebrafish larvae recapitulate key aspects of tuberculosis pathogenesis and drug treatment. Here, we develop a model for rapid in vivo drug screening using fluorescence-based methods for serial quantitative assessment of drug efficacy and toxicity. We provide proof-of-concept that both traditional bacterial-targeting antitubercular drugs and newly identified host-targeting drugs would be discovered through the use of this model. We demonstrate the model's utility for the identification of synergistic combinations of antibacterial drugs and demonstrate synergy between bacterial- and host-targeting compounds. Thus, the platform can be used to identify new antibacterial agents and entirely new classes of drugs that thwart infection by targeting host pathways. The methods developed here should be widely applicable to small-molecule screens for other infectious and noninfectious diseases.

Revisiting the role of the granuloma in tuberculosis

The granuloma, which is a compact aggregate of immune cells, is the hallmark structure of tuberculosis. It is historically regarded as a host-protective structure that 'walls off' the infecting mycobacteria. This Review discusses surprising new discoveries--from imaging studies coupled with genetic manipulations--that implicate the innate immune mechanisms of the tuberculous granuloma in the expansion and dissemination of infection. It also covers why the granuloma can fail to eradicate infection even after adaptive immunity develops. An understanding of the mechanisms and impact of tuberculous granuloma formation can guide the development of therapies to modulate granuloma formation. Such therapies might be effective for tuberculosis as well as for other granulomatous diseases.

Modeling innate immune response to early Mycobacterium infection.

In the study of complex patterns in biology, mathematical and computational models are emerging as important tools. In addition to experimental approaches, these modeling tools have recently been applied to address open questions regarding host-pathogen interaction dynamics, including the immune response to mycobacterial infection and tuberculous granuloma formation. We present an approach in which a computational model represents the interaction of the Mycobacterium infection with the innate immune system in zebrafish at a high level of abstraction. We use the Petri Net formalism to model the interaction between the key host elements involved in granuloma formation and infection dissemination. We define a qualitative model for the understanding and description of causal relations in this dynamic process. Complex processes involving cell-cell or cell-bacteria communication can be modeled at smaller scales and incorporated hierarchically into this main model; these are to be included in later elaborations. With the infection mechanism being defined on a higher level, lower-level processes influencing the host-pathogen interaction can be identified, modeled, and tested both quantitatively and qualitatively. This systems biology framework incorporates modeling to generate and test hypotheses, to perform virtual experiments, and to make experimentally verifiable predictions. Thereby it supports the unraveling of the mechanisms of tuberculosis infection.

Tumor Necrosis Factor Signaling Mediates Resistance to Mycobacteria by Inhibiting Bacterial Growth and Macrophage Death

Tumor necrosis factor (TNF), a key effector in controlling tuberculosis, is thought to exert protection by directing formation of granulomas, organized aggregates of macrophages and other immune cells. Loss of TNF signaling causes progression of tuberculosis in humans, and the increased mortality of Mycobacterium tuberculosis-infected mice is associated with disorganized necrotic granulomas, although the precise roles of TNF signaling preceding this endpoint remain undefined. We monitored transparent Mycobacterium marinum-infected zebrafish live to conduct a stepwise dissection of how TNF signaling operates in mycobacterial pathogenesis. We found that loss of TNF signaling caused increased mortality even when only innate immunity was operant. In the absence of TNF, intracellular bacterial growth and granuloma formation were accelerated and was followed by necrotic death of overladen macrophages and granuloma breakdown. Thus, TNF is not required for tuberculous granuloma formation, but maintains granuloma integrity indirectly by restricting mycobacterial growth within macrophages and preventing their necrosis.

Association between RANTES functional polymorphisms and tuberculosis in Hong Kong Chinese

Chemokines play a major role in leukocyte recruitment during the formation of tuberculous granulomas. We studied the association between genetic polymorphisms of three chemokines, monocyte chemoattractant protein-1 (MCP-1), RANTES (regulated on activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1alpha (MIP-1alpha), and tuberculosis (TB). The distribution of five functionally significant single-nucleotide polymorphisms (SNPs), MCP-1 -2518A/G, RANTES -403G/A, -28C/G and In1.1T/C as well as MIP-1alpha +459C/T was not found to be different between patients with TB and healthy control subjects of the Hong Kong Chinese population. However, differences in linkage disequilibrium (LD) of the SNPs of RANTES and in distribution of the haplotypes of RANTES between patients with TB and healthy controls (P<0.0001) were found. Two risk haplotypes of RANTES, A-C-T and G-C-C, at positions -403, -28 and In1.1, respectively, were identified. Furthermore, combining the genotypes of RANTES -403 and In1.1, two diplotypes GA/TT (P<0.001) and GG/TC (P<0.0001) showed strong association with TB. Our findings support the association between RANTES functional polymorphisms and TB.

Tuberculous Granuloma Formation Is Enhanced by a Mycobacterium Virulence Determinant

Granulomas are organized host immune structures composed of tightly interposed macrophages and other cells that form in response to a variety of persistent stimuli, both infectious and noninfectious. The tuberculous granuloma is essential for host containment of mycobacterial infection, although it does not always eradicate it. Therefore, it is considered a host-beneficial, if incompletely efficacious, immune response. The Mycobacterium RD1 locus encodes a specialized secretion system that promotes mycobacterial virulence by an unknown mechanism. Using transparent zebrafish embryos to monitor the infection process in real time, we found that RD1-deficient bacteria fail to elicit efficient granuloma formation despite their ability to grow inside of infected macrophages. We showed that macrophages infected with virulent mycobacteria produce an RD1-dependent signal that directs macrophages to aggregate into granulomas. This Mycobacterium-induced macrophage aggregation in turn is tightly linked to intercellular bacterial dissemination and increased bacterial numbers. Thus, mycobacteria co-opt host granulomas for their virulence.

Expression of transforming growth factor-β but not tumor necrosis factor-α, interferon-γ, and interleukin-4 in granulomatous lung lesions in tuberculosis

The expression of transforming growth factor (TGF-β1), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin-4 (IL-4) were assessed in lung tissues from patients with tuberculosis. Vimentin, a constitutively expressed cellular protein, was present in 12 of 19 tissue sections indicating adequate preservation of tissue proteins in these cases. Immunohistochemical studies for cytokines were done in the vimentin positive sections only. TGF-β1 was localized to mononuclear phagocytes of tuberculous lung lesions in 4 of 12 tuberculosis patients. TNF-α, IFN-γ, and IL-4 were absent in sections from all tuberculosis patients. The failure to detect the latter cytokines may indicate that these molecules may not be expressed at the site of disease, or are not a feature of the late stages of tuberculous granulomas. TGFβ -1, although not universally expressed, may be involved in the development and/or consequences of tuberculous granuloma formation. These data substantiate further the role of TGF-β1 in the immunopathology of tuberculosis.

Tuberculoma of spinal cord.

The incidence of formation of tuberculous granulomas of the spinal cord is rare enough that we thought it worthwhile to report in detail a case we have recently observed. The first tuberculoma of the spinal cord was described in 1830 by Serre 1 in France. During the following 105 years only 87 such cases have been described in the world literature. 2 In reviewing the literature since 1935, we have been able to find only 84 more cases in the English-speaking literature. The pathogenesis of tuberculoma of the spinal cord is now thought to be 3 : 1. A tubercle forms in the spinal cord or in the membranes, being blood-borne in the vast majority of instances. 2. This tubercle provokes a reactive phenomenon that causes proliferation of powerful connective tissue elements that form the granuloma. 3. Drainage persists into and by the subarachnoid space. 4. An inflammatory reaction occurs in