Necrosis, netosis, and apoptosis in pulmonary tuberculosis and type-2 diabetes mellitus. Clues from the patient's serum.

Pulmonary tuberculosis (PTB) and type 2 diabetes mellitus (T2DM) are two inflammatory diseases whose pathology involves neutrophils (NEU) as key participants. Countless inflammatory elements produced at the lesion sites leak into the blood and are distributed systemically. The study aimed to investigate the effect of the serum of patients with PTB, T2DM, and PTB + T2DM on the cellular and nuclear morphology of healthy NEU. Monolayers of NEU were prepared and incubated with sera from PTB (n꓿ 10), T2DM (n꓿10), PTB + T2DM (n꓿ 10) patients, or sera from healthy people (n = 10). Monolayers were stained for histones, elastase, and myeloperoxidase for NETosis, annexin V for apoptosis, and Iris fuchsia for necrosis. Hoechst stain (DNA) was used to identify the nuclear alterations. Necrosis was the predominant alteration. Sera from PTB + T2DM were the most potent change inducers. Normal sera did not induce cell alterations. The blood of TBP and T2DM patients carries a myriad of abnormal elements that induce necrosis of NEU in normal people, thus reflecting what might occur in the neutrophils of the patients themselves. These findings reinforce the participation of NEU in the pathology of these diseases. Necrosis is expected to be the most frequent neutrophil-induced alteration in tuberculosis and diabetes mellitus.

A neutrophil-based test as an auxiliary tool for substantiating the diagnosis of bovine tuberculosis.

Background: Bovine tuberculosis (bTB) is still a prominent threat to animal health; lacking an efficient vaccine, other than BCG to get rid of tuberculosis, the most effective way for this is culling and slaughtering the infected animals. There are several cellular, serological, and molecular tests for the diagnosis of the disease but the most practical one at the field level is the double skin testing with bovine and aviary tuberculins. This is not a very specific test but is sensitive enough to identify most diseased animals; adjunct practical tests are desirable to strengthen the utility of skin tests. All lymphoid and myeloid cells participate, in diverse grades, in the immune response to tuberculosis with neutrophils playing an unintended pathologic role. The study aimed to investigate the response of neutrophils to agents present in the sera of tuberculous cows. Methods: We have developed a neutrophil-based test (N BT) to identify diseased cows within a herd suspected of having tuberculosis; a positive N BT correlates with a positive double skin test. In this test, healthy neutrophils are incubated with the sera of healthy or tuberculous cows for 3 and 6 h, and the nuclear morphologic changes are recorded and analyzed. Results: Sera from tuberculous but not from healthy cows induce nuclear alterations including pyknosis, swelling, apoptosis, and sometimes NETosis, in healthy neutrophils, and CFP 10 and ESAT 6 participate in the phenomenon. Conclusion: We propose the N BT as an auxiliary tool for substantiating the diagnosis of bTB reinforcing the PPD test outcome to help decide whether or not a cow should be sacrificed.

Natural marine products as antiprotozoal agents against amitochondrial parasites.

The goal of this work is to compile and discuss molecules of marine origin reported in the scientific literature with anti-parasitic activity against Trichomonas, Giardia, and Entamoeba, parasites responsible for diseases that are major global health problems, and Microsporidial parasites as an emerging problem. The presented data correspond to metabolites with anti-parasitic activity in human beings that have been isolated by chromatographic techniques from marine sources and structurally elucidated by spectroscopic and spectrometric procedures. We also highlight some semi-synthetic derivatives that have been successful in enhancing the activity of original compounds. The biological oceanic reservoir offers the possibility to discover new biologically active molecules as lead compounds to develop new drug candidates. The molecular variety is extensive and must be correctly explored and managed. Also, it will be necessary to take some actions to preserve the source species from extinction or overharvest (e.g., by cryopreservation of coral spermatozoa, oocytes, embryos, and larvae) and coordinate appropriate exploitation to increase the chemical knowledge of the natural products generated in the oceans. Additional initiatives such as the total synthesis of complex natural products and their derivatives can help to prevent overharvest of the marine ecosystems and at the same time contribute to the discovery of new molecules.

NeuroImmunoEndocrinology: A brief historic narrative.

Although no precise moment or unique event marks its birth, neuroimmunoendocrinology arguably shares a great deal of history with other medical and biologic disciplines. It originated from empirical observations and suppositions that failed to prevail upon the existing axioms. Despite the widespread resistance to embracing novel ideas, the seeming defeats inspired visionary researchers. Those pioneers managed to systematize the emerging knowledge and were able to contribute to science with real foundations. In consequence, new concepts and ideas arose in physiology, anatomy, endocrinology and early immunology. Together, they gave rise to a budding approach on the integration between the nervous, immune and endocrine systems. Then, neuroimmunoendocrinology emerged as a discipline integrating an intricate system with multidirectional functions and interactions that allow for responding to internal and external threats. Such response is mediated by cytokines, hormones and neurotransmitters, involved in different physiologic mechanisms of the organism homeostasis. Neuroimmunoendocrinology is no longer an area of scientific skepticism; on the contrary, it has cemented its position as a biomedical discipline worldwide for the past 70 years. Now, it offers a better understanding of pathologic processes.

Sera from patients with tuberculosis increase the phagocytic-microbicidal activity of human neutrophils, and ESAT-6 is implicated in the phenomenon.

Background: It has been reported that sera from patients with active pulmonary tuberculosis (APT) induced nuclear changes in normal neutrophils that included pyknosis, swelling, apoptosis, and production of extracellular traps (NETs). Similar changes were observed with some sera from their household contacts but not with sera from healthy, unrelated individuals. It was suggested that those sera from household contacts that induced neutrophil nuclear changes might correspond to people with subclinical tuberculosis. Thus, our experimental approach might serve to identify individuals with early, ongoing disease. Methods: Nuclear changes in neutrophils were fully evident by 3 h of contact and beyond. Circulating mycobacterial antigens were the most likely candidates for this effect. We wanted to know whether the nuclear changes induced on neutrophils by the sera of APT patients would negatively affect the phagocytic/microbicidal ability of neutrophils exposed to APT sera for short periods. Results: We now provide evidence that short-term contact (30 min) with sera from patients with pulmonary tuberculosis increases several phagocytic parameters of normal neutrophils, including endocytosis, myeloperoxidase levels, production of free reactive oxygen species, phagolysosome fusion, and microbicidal activity on Staphylococcus aureus, with these effects not being observed with sera from healthy donors. We also give evidence that suggests that ESAT-6 and CFP-10 are involved in the phenomenon. Conclusion: We conclude that activation is a stage that precedes lethal nuclear changes in neutrophils and suggests that autologous neutrophils must circulate in an altered state in the APT patients, thus contributing to the pathology of the disease.

Effect of dialyzable leukocyte extract, sodium butyrate, and valproic acid in the development of anergy in murine leprosy.

Background: Murine leprosy is a chronic granulomatous disease caused by Mycobacterium lepraemurium (MLM) in mice and rats. The disease evolves with the development of cellular anergy that impedes the production of interferon gamma (IFNγ), tumor necrosis factor-alpha (TNFα), and nitric oxide (NO) required to kill the microorganism. In this study we investigated whether histone deacetylase inhibitors (HDACi) (valproic acid and sodium butyrate [NaB]) and the immunomodulator transfer factor in dialyzable leukocyte extracts (DLE) can prevent anergy in murine leprosy. Methods: Five groups of six Balb/c mice were intraperitoneally inoculated with 2 × 107 MLM. Thirty-days post inoculation, treatment was started; one group received no treatment, one was treated with rifampicin-clofazimine (R-C), one with sodium valproate (VPA), one with NaB, and one with DLE. The animals were monitored for the evidence of disease for 96 days. After euthanasia, their spleens were removed and processed for histologic, bacteriologic, and cytokine studies. Results: R-C completely controlled the ongoing disease. DLE and NaB significantly reduced the development of lesions, including granuloma size and the number of bacilli; VPA was less effective. DLE, NaB, and VPA reverted the anergic condition in diverse grades and allowed the expression of IFNγ, TNFα, and inducible NO synthase, also in diverse grades. Conclusion: Anergy in leprosy and murine leprosy allows disease progression. In this study, anergy was prevented, in significant degree, by DLE (an immunomodulator) and NaB (HDACi). VPA was less effective. These results suggest potential beneficial effects of DLE and NaB in the ancillary treatment of leprosy.

Anti-inflammatory effect of omega unsaturated fatty acids and dialysable leucocyte extracts on collagen-induced arthritis in DBA/1 mice.

Rheumatoid arthritis is a disabling autoimmune disease with a high global prevalence. Treatment with disease-modifying anti-arthritic drugs (DIMARDs) has been routinely used with beneficial effects but with adverse long-term consequences; novel targeted biologics and small-molecule inhibitors are promising options. In this study, we investigated whether purified omega unsaturated fatty acids (ω-UFAs) and dialysable leukocyte extracts (DLEs) prevented the development of arthritis in a model of collagen-induced arthritis (CIA) in mice. We also investigated whether the transcription factor NF-κB and the NLRP3 inflammasome were involved in the process and whether their activity was modulated by treatment. The development of arthritis was evaluated for 84 days following treatment with nothing, dexamethasone, DLEs, docosahexaenoic acid, arachidonic acid, and oleic acid. Progression of CIA was monitored by evaluating clinical manifestations, inflammatory changes, and histological alterations in the pads' articular tissues. Both DLEs and ω-UFAs led to an almost complete inhibition of the inflammatory histopathology of CIA and this was concomitant with the inhibition of NF-kB and the inhibition of the activation of NLRP3. These data suggest that ω-UFAs and DLEs might have NF-κB as a common target and that they might be used as ancillary medicines in the treatment of arthritis.

Sera from patients with active pulmonary tuberculosis and their household contacts induce nuclear changes in neutrophils.

BACKGROUND: Resident alveolar macrophages, dendritic cells, and immigrating neutrophils (NEU) are the first cells to contact Mycobacterium tuberculosis in the lung. These cells, and additional lymphoid cells in the developing granuloma, release a series of components that may concentrate in the serum and affect disease progression. PURPOSE: The aim of this study was to investigate the effect of the serum from tuberculosis (TB) patients and their household contacts (HHC) on the nuclear morphology of NEU. MATERIALS AND METHODS: NEU from healthy (HLT) people were incubated with sera from patients with active pulmonary TB, their HHC, and unrelated people. Changes in the nuclear morphology of NEU were analyzed by light and electron microscopy. RESULTS: Sera from patients with TB induced changes in the nuclear morphology of NEU that included pyknosis, swelling, apoptosis, and netosis in some cases. Sera from some HHC induced similar changes, while sera from HLT people had no significant effects. Bacteria did not appear to participate in this phenomenon because bacteremia is not a recognized feature of nonmiliary TB, and because sera from patients that induced nuclear changes maintained their effect after filtration through 0.22 µm membranes. Neither anti-mycobacterial antibodies, TNFα, IL-6, IFNγ, or IL-8 participated in the phenomenon. In contrast, soluble mycobacterial antigens were likely candidates, as small quantities of soluble M. tuberculosis antigens added to the sera of HLT people led to the induction of nuclear changes in NEU in a dose-dependent manner. CONCLUSION: These results might help to detect subclinical TB within HHC, thus leading to a recommendation of prophylactic treatment.

Chronic infection with Mycobacterium lepraemurium induces alterations in the hippocampus associated with memory loss.

Murine leprosy, caused by Mycobacterium lepraemurium (MLM), is a chronic disease that closely resembles human leprosy. Even though this disease does not directly involve the nervous system, we investigated a possible effect on working memory during this chronic infection in Balb/c mice. We evaluated alterations in the dorsal region of the hippocampus and measured peripheral levels of cytokines at 40, 80, and 120 days post-infection. To evaluate working memory, we used the T-maze while a morphometric analysis was conducted in the hippocampus regions CA1, CA2, CA3, and dentate gyrus (DG) to measure morphological changes. In addition, a neurochemical analysis was performed by HPLC. Our results show that, at 40 days post-infection, there was an increase in the bacillary load in the liver and spleen associated to increased levels of IL-4, working memory deterioration, and changes in hippocampal morphology, including degeneration in the four subregions analyzed. Also, we found a decrease in neurotransmitter levels at the same time of infection. Although MLM does not directly infect the nervous system, these findings suggest a possible functional link between the immune system and the central nervous system.

Insights from the Genome Sequence of Mycobacterium lepraemurium: Massive Gene Decay and Reductive Evolution.

Mycobacterium lepraemurium is the causative agent of murine leprosy, a chronic, granulomatous disease similar to human leprosy. Due to the similar clinical manifestations of human and murine leprosy and the difficulty of growing both bacilli axenically, Mycobacterium leprae and M. lepraemurium were once thought to be closely related, although it was later suggested that M. lepraemurium might be related to Mycobacterium avium In this study, the complete genome of M. lepraemurium was sequenced using a combination of PacBio and Illumina sequencing. Phylogenomic analyses confirmed that M. lepraemurium is a distinct species within the M. avium complex (MAC). The M. lepraemurium genome is 4.05 Mb in length, which is considerably smaller than other MAC genomes, and it comprises 2,682 functional genes and 1,139 pseudogenes, which indicates that M. lepraemurium has undergone genome reduction. An error-prone repair homologue of the DNA polymerase III α-subunit was found to be nonfunctional in M. lepraemurium, which might contribute to pseudogene formation due to the accumulation of mutations in nonessential genes. M. lepraemurium has retained the functionality of several genes thought to influence virulence among members of the MAC.IMPORTANCEMycobacterium lepraemurium seems to be evolving toward a minimal set of genes required for an obligatory intracellular lifestyle within its host, a niche seldom adopted by most mycobacteria, as they are free-living. M. lepraemurium could be used as a model to elucidate functions of genes shared with other members of the MAC. Its reduced gene set can be exploited for studying the essentiality of genes in related pathogenic species, which might lead to discovery of common virulence factors or clarify host-pathogen interactions. M. lepraemurium can be cultivated in vitro only under specific conditions and even then with difficulty. Elucidating the metabolic (in)capabilities of M. lepraemurium will help develop suitable axenic media and facilitate genetic studies.

In vivo induction of neutrophil extracellular traps by Mycobacterium tuberculosis in a guinea pig model.

In 2004, a novel mechanism of cellular death, called 'NETosis', was described in neutrophils. This mechanism, different from necrosis and apoptosis, is characterized by the release of chromatin webs admixed with microbicidal granular proteins and peptides (NETs). NETs trap and kill a variety of microorganisms. Diverse microorganisms, including Mycobacterium tuberculosis, are NET inducers in vitro. The aim of this study was to examine whether M. tuberculosis can also induce NETs in vivo and if the NETs are bactericidal to the microorganism. Guinea pigs were intradermally inoculated with M. tuberculosis H37Rv, and the production of NETs was investigated at several time points thereafter. NETs were detected as early as 30 min post-inoculation and were clearly evident by 4 h post-inoculation. NETs produced in vivo contained DNA, myeloperoxidase, elastase, histones, ROS and acid-fast bacilli. Viable and heat-killed M. tuberculosis, as well as Mycobacterium bovis BCG were efficient NET inducers, as were unilamellar liposomes prepared with lipids from M. tuberculosis. In vitro, guinea pig neutrophils also produced NETs in response to M. tuberculosis. However, neither the in vivo nor the in vitro-produced NETs were able to kill M. tuberculosis. Nevertheless, in vivo, neutrophils might propitiate recruitment and activation of more efficient microbicidal cells.

Mycobacterium lepraemurium uses TLR-6 and MR, but not lipid rafts or DC-sign, to gain access into mouse macrophages.

OBJECTIVE/BACKGROUND: Mycobacterium lepraemurium (MLM), the etiologic agent of murine leprosy, is an intracellular parasite of macrophages; the mechanism used by this bacterium to enter macrophages is not known. The fate of the MLM phagosome inside macrophages is also unknown. This study was conducted to investigate how MLM enters macrophages and to define the maturation process of MLM phagosome inside macrophages. MATERIALS AND METHODS: Peritoneal macrophages were incubated in the presence of mannan-bovine serum albumin (BSA), and antibodies to known macrophage receptors, including, anti-FcγRIII/RII (anti-CD16/32), anti-CD35 (anti-CR1), anti-TLR2, anti-TLR4, anti-TLR6, anti-CD14, and anti-dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN). Then, macrophages were challenged with Iris Fuchsia-stained MLM, at a multiplicity of infection of 50:1. The blocking effect of the antibodies (and mannan-BSA) used was analyzed using direct microscopy and flow cytometry. The maturation process of MLM phagosomes was visualized by their interaction with antibodies to Rab5, Rab7, proton ATPase, and cathepsin D, by confocal microscopy. RESULTS: Only mannan-BSA and anti-TLR6 antibody significantly blocked the entry of MLM into macrophages. None of the other antibodies, including that for DC-SIGN, meaningfully inhibited the endocytic process. We also found that MLM is a fusiogenic mycobacterium. This was deduced from the orderly association of MLM phagosomes with Rab5, Rab7, Proton ATPase, and lysosomes (cathepsin D). CONCLUSION: Fusion of MLM phagosomes with lysosomes seems to be a necessary event for the intracellular multiplication of MLM; similar to Mycobacterium leprae, this microorganism hardly grows on artificial, synthetic, bacteriologic media.

Dengue Virus Serotype-2 Interferes with the Formation of Neutrophil Extracellular Traps.

OBJECTIVES: Neutrophils play an important role in the control of pathogens through several mechanisms, including phagocytosis and the formation of neutrophil extracellular traps (NETs). The latter consists of DNA as a backbone with embedded antimicrobial peptides, histones, and proteases, providing a matrix to entrap and in some cases to kill microbes. Some metabolic requirements for NET formation have recently been described. The virus-induced formation of NETs and the role of these traps in viral infections remain scarcely reported. Here, we analyzed whether dengue virus serotype-2 (DENV-2) induces NET formation and the DENV-2 effect on phorbol myristate acetate (PMA)-induced NETs. METHODS: Peripheral blood-derived neutrophils were exposed in vitro to DENV-2 or exposed to DENV-2 and then stimulated with PMA. NET formation was assessed by fluorescence microscopy. Cell membrane Glut-1, glucose uptake, and reactive oxygen species (ROS) production were assessed. RESULTS: DENV-2 does not induce the formation of NETs. Moreover, DENV-2 inhibits PMA-induced formation of NETs by about 80%. This effect is not related to the production of ROS. The mechanism seemingly accountable for this inhibitory effect is the DENV-2-mediated inhibition of PMA-induced glucose uptake by neutrophils. CONCLUSION: Our results suggest that DENV-2 inhibits glucose uptake as a metabolism-based way to avoid the formation of NETs.

Low expression of IL-6 and TNF-α correlates with the presence of the nuclear regulators of NF-κB, IκBNS and BCL-3, in the uterus of mice.

The dynamic regulation of NF-κB activity in the uterus maintains a favorable environment of cytokines necessary to prepare for pregnancy throughout the estrous cycle. Recently, the mechanisms that directly regulate the NF-κB transcriptional activity in different tissues are of growing interest. IκBNS and BCL-3 are negative nuclear regulators of NF-κB activity that regulate IL-6 and TNF-α transcription, respectively. Both cytokines have been described as important factors in the remodeling of uterus for blastocyst implantation. In this work we analyzed in ICR mice the mRNA expression and protein production profile of IL-6, TNF-α, and their correspondent negative transcription regulators IκBNS or BCL-3 using real-time PCR, western blot and immunochemistry. We found that the expression of TNF-α and IL-6 was oscillatory along the estrous cycle, and its low expression coincided with the presence of BCL-3 and IκBNS, and vice versa, when the presence of the regulators was subtle, the expression of TNF-α and IL-6 was exacerbated. When we compared the production of TNF-α and IL-6 in the different estrous stages relating with diestrus we found that at estrus there is an important increase of the cytokines (p<0.05) decreasing at metestrus to reach the basal expression at diestrus. In the immunochemistry analysis we found that at diestrus BCL-3 is distributed all over the tissue with a barely detected TNF-α, but on the contrary, at estrus the expression of BCL-3 is not detected with TNF-α clearly observable along the tissue; the same phenomenon occur in the analysis of IκBNS and IL-6. With that evidence we suggest that the expression of TNF-α and IL-6 might be regulated through NF-κB nuclear regulators BCL-3 and IκBNS in the uterus of mice as has been demonstrated in other systems.

Induction and treatment of anergy in murine leprosy.

Leprosy is a disease consisting of a spectrum of clinical, bacteriological, histopathological and immunological manifestations. Tuberculoid leprosy is frequently recognized as the benign polar form of the disease, while lepromatous leprosy is regarded as the malignant form. The different forms of leprosy depend on the genetic and immunological characteristics of the patient and on the characteristics of the leprosy bacillus. The malignant manifestations of lepromatous leprosy result from the mycobacterial-specific anergy that develops in this form of the disease. Using murine leprosy as a model of anergy in this study, we first induced the development of anergy to Mycobacterium lepraemurium (MLM) in mice and then attempted to reverse it by the administration of dialysable leucocyte extracts (DLE) prepared from healthy (HLT), BCG-inoculated and MLM-inoculated mice. Mice inoculated with either MLM or BCG developed a robust cell-mediated immune response (CMI) that was temporary in the MLM-inoculated group and long-lasting in the BCG-inoculated group. DLE were prepared from the spleens of MLM- and BCG-inoculated mice at the peak of CMI. Independent MLM intradermally-inoculated groups were treated every other day with HLT-DLE, BCG-DLE or MLM-DLE, and the effect was documented for 98 days. DLE administered at a dose of 1.0 U (1 × 10(6) splenocytes) did not affect the evolution of leprosy, while DLE given at a dose of 0.1 U showed beneficial effects regardless of the DLE source. The dose but not the specificity of DLE was the determining factor for reversing anergy.

Metabolic requirements for neutrophil extracellular traps formation.

As part of the innate immune response, neutrophils are at the forefront of defence against infection, resolution of inflammation and wound healing. They are the most abundant leucocytes in the peripheral blood, have a short lifespan and an estimated turnover of 10(10) to 10(11) cells per day. Neutrophils efficiently clear microbial infections by phagocytosis and by oxygen-dependent and oxygen-independent mechanisms. In 2004, a new neutrophil anti-microbial mechanism was described, the release of neutrophil extracellular traps (NETs) composed of DNA, histones and anti-microbial peptides. Several microorganisms, bacterial products, as well as pharmacological stimuli such as PMA, were shown to induce NETs. Neutrophils contain relatively few mitochondria, and derive most of their energy from glycolysis. In this scenario we aimed to analyse some of the metabolic requirements for NET formation. Here it is shown that NETs formation is strictly dependent on glucose and to a lesser extent on glutamine, that Glut-1, glucose uptake, and glycolysis rate increase upon PMA stimulation, and that NET formation is inhibited by the glycolysis inhibitor, 2-deoxy-glucose, and to a lesser extent by the ATP synthase inhibitor oligomycin. Moreover, when neutrophils were exposed to PMA in glucose-free medium for 3 hr, they lost their characteristic polymorphic nuclei but did not release NETs. However, if glucose (but not pyruvate) was added at this time, NET release took place within minutes, suggesting that NET formation could be metabolically divided into two phases; the first, independent from exogenous glucose (chromatin decondensation) and, the second (NET release), strictly dependent on exogenous glucose and glycolysis.

Pathogenic CCR6+ dendritic cells in the skin lesions of discoid lupus patients: a role for damage-associated molecular patterns.

BACKGROUND: Discoid lupus erythematosus (DLE) is a cutaneous autoimmune inflammatory disease in which the role of conventional dendritic cells (cDCs) in skin damage has not been evaluated. OBJECTIVE: To evaluate the involvement of cDCs in DLE pathogenesis. MATERIAL & METHODS: Skin biopsies from 42 patients with DLE were embedded in paraffin or placed in culture. The dermis was separated and cell suspensions were characterized by flow cytometry. RESULTS: We found an increase in cDCs with inflammatory characteristics in the skin of DLE patients, compared with control skins. Interestingly, cDCs from the DLE patients expressed low levels of the inhibitory molecule PD-L1 and showed a high expression of CCR6, which correlated with disease activity. Increased cellular death was observed in the skin of DLE patients compared with control skin and remarkably we found that damage-associated molecular patterns could be responsible for CCR6 expression on cDCs in the skin. CONCLUSIONS: Our results indicate the presence of pathogenic CCR6+ cDCs in the skin lesions of DLE patients, which could result from in situ phenotypic changes.

Fate of Mycobacterium tuberculosis in peroxidase-loaded resting murine macrophages.

BACKGROUND: Myeloperoxidase (MPO), in the presence of hydrogen peroxide and a halide represent an efficient microbicidal mechanism of phagocytic cells. MPO is abundant in neutrophils which also respond to infection by producing large amounts of reactive oxygen species (ROS). MPO, ROS and halide constitute a very toxic antimicrobial system (called the Klebanoff system or KS). Resting mature macrophages do not contain granular MPO and thus are unable to kill pathogenic mycobacteria and some other microorganisms by this system. EXPERIMENTAL: Under the hypothesis that transforming macrophages into peroxidase-positive (PO(+)) cells, these cells would be able to kill Mycobacterium tuberculosis, in this study, mature macrophages were loaded with exogenous peroxidase and were tested for their capacity to kill the Mycobacterium in the presence or in the absence of hydrogen peroxide. RESULTS: It was found that PO-loaded macrophages eagerly ingest M. tuberculosis, but do not show a significant mycobactericidal activity on this microorganism despite that it is highly susceptible to the Klebanoff system in vitro. Failure of PO-loaded macrophages to kill M. tuberculosis may obey either to an inappropriate location of the exogenous PO in these cells or more likely, to the presence of efficient detoxifying mechanisms in the bacteria. On the contrary, MPO-loaded or unloaded macrophages efficiently killed Listeria monocytogenes. CONCLUSION: The lack of granular MPO in mature macrophages, and the predilection of mycobacteria to infect these cells are two situations that favor the development of tuberculosis and related diseases, such as leprosy and Buruli ulcer.

Functional state analysis of phagocytic cells of patients with type 2 diabetes and pulmonary tuberculosis.

BACKGROUND: The phagocytic function in pulmonary tuberculosis (PTB) and Type 2 diabetes (T2D) has been explored mainly in macrophages but not in polymorphonuclears (PMN). The purpose of this study was to determine the functional status of PMN leukocytes in patients with pulmonary tuberculosis (PTB), Type 2 diabetes (T2D), and in patients with both diseases. METHODS: An observational, prospective, and comparative study was carried out. 30 ambulatory patients with T2D, 10 with PTB undergoing treatment and 10 patients with PTB and T2D, and 44 healthy subjects were studied. PMN leukocytes were separated, the capacity of these cells to produce hydrogen peroxide and to reduce nitroblue tetrazolium (NBT) in response to stimulus with the phorbolic ester of myristic acid (PMA) was measured; and the capacity of PMN leukocytes to adhere to surfaces was determined. RESULTS: Concerning the test for adherence, on comparing healthy subjects with patients with T2D+PTB, we observed a clear decrease in cellular adherence in the group of patients with both diseases; it was statistically significant (p = 0.007).With regard to phagocytic function, we observed that in NBT reduction as well as in hydrogen peroxide production, statistically significant differences were not obtained on comparing healthy subjects with any of the three groups of patients. CONCLUSIONS: We observed a clear decrease in cellular adherence when both diseases co-exist. These results could indicate the need for the co-existence of T2D and TB to cause deterioration in the cells' adherence activity. The microtechniques employed permit the evaluation in a practical manner of certain phagocytic-activity expressions.

The use of the microplate alamar blue assay (MABA) to assess the susceptibility of Mycobacterium lepraemurium to anti-leprosy and other drugs.

Although murine leprosy is no longer a common illness, our understanding of the biology of this disease is incomplete. One particular example of this concerns the etiologic agent Mycobacterium lepraemurium (MLM). MLM is a fastidious microorganism that is difficult to grow in axenic media; in a way, this has hampered attempts to thoroughly study its physiological and metabolic characteristics. MLM is an obligate intracellular bacillus that invades macrophages and replicates profusely with a generation time that oscillates between 0.5 and 11 days. In the present study, we have successfully maintained MLM alive for more than 12 days in vitro, providing us with an opportunity to study its susceptibility to several anti-leprosy agents and other drugs. To achieve this, we used a fluorescence reduction assay of alamar blue (a resazurin) in a microplate format (microplate-alamar-blue-assay; MABA), which is a highly sensitive, practical, and inexpensive method for assaying cell viability. We found that MLM was highly susceptible to clofazimine and rifampicin and was less susceptible to streptomycin, thiacetazone, kanamycin, dapsone, and ethionamide, in that order. MLM was not susceptible to four plant triterpenoids (oleanolic acid, neolignan-c, sitosterol, and ursolic acid) for which bactericidal activity has been reported in M. tuberculosis. Because the MABA has high sensitivity, it can be used to monitor the activity of microorganisms that are difficult to cultivate (such as M. lepraemurium), in response to various drugs, thus offering a method to complement the study of murine leprosy, about which many questions remain unanswered.