Tuberculosis and lung damage: from epidemiology to pathophysiology

Vaccination in post-tuberculosis lung disease management: A review of the evidence

INTRODUCTION AND OBJECTIVES

Post-tuberculosis lung disease (PTLD), as other chronic respiratory disorders, may have infectious complications; some of them can be prevented with vaccinations. So far, no document has discussed the potential role of vaccination in PTLD. Therefore, the objective of this review was to describe vaccination recommendations to prevent infections potentially capable of complicating PTLD.

MATERIALS AND METHODS

A non-systematic review of the literature was conducted. The following keywords were used: tuberculosis, vaccination, vaccines and PTLD. PubMed/MEDLINE and Embase were used as the search engine, focusing on English-language literature only.

RESULTS

We identified 9 vaccines potentially useful in PTLD. Influenza, pneumococcal and anti-COVID-19 vaccinations should be recommended. Patients with PTLD can also benefit from vaccination against shingles. Vaccination against pertussis is mainly relevant during childhood. Diphtheria, tetanus and measles vaccination are recommended for general population and should be considered in patients with PTLD not previously vaccinated. Tdap (Tetanus, diphtheria, and pertussis) booster should be repeated in every adult every ten years. Vaccination against BCG retains its importance during early childhood in countries where TB is endemic.

CONCLUSIONS

Vaccination deserves to be considered among the strategies to prevent and/or mitigate PTLD complications. Further evidence is necessary to better understand which vaccines have the greatest impact and cost-benefit.

Correlative 3D imaging method for analysing lesion architecture in susceptible mice infected with Mycobacterium tuberculosis

Tuberculosis (TB) is characterized by the formation of heterogeneous, immune-rich granulomas in the lungs. Host and pathogen factors contribute to this heterogeneity, but the molecular and cellular drivers of granuloma diversity remain inadequately understood owing to limitations in experimental techniques. In this study, we developed an approach that combines passive CLARITY (PACT)-based clearing with light-sheet fluorescence microscopy to visualize lesion architecture and lung involvement in Mycobacterium tuberculosis-infected C3HeB/FeJ mice. Three-dimensional rendering of post-mortem lungs revealed critical architectural features in lesion development that traditional thin-section imaging could not detect. Wild-type M. tuberculosis infection resulted in organized granulomas, with median sizes increasing to 3.74×108 µm3 and occupying ∼10% of the total lung volume by day 70 post-infection. In contrast, infection with the avirulent ESX-1 deletion mutant strain resulted in diffuse and sparsely organized CD11b recruitment (median size of 8.22×107 µm3), primarily located in the lung periphery and minimally involving the airways (0.23% of the total lung space). Additionally, we present a method for volumetric correlative light and electron microscopy, enabling tracking of individual immune cell populations within granulomas.

Prevalence and short-term outcomes of acute complications of tuberculosis: a cross-sectional, monocentre, Italian study

BACKGROUND

Tuberculosis (TB) is a major cause of morbidity and mortality worldwide. Acute complications may impact on disease progression but their prevalence is unclear and prognostic outcomes of complicated patients have been poorly studied. The aim of the study was to estimate the prevalence of acute complications of TB at the time of diagnosis. Short-term outcomes were also evaluated.

METHODS

A cross-sectional study was carried out in Milan (Italy), from January 2018 to December 2023.

RESULTS

201 patients with TB were recruited. 88 complications were recorded in 65 (32.3%) patients. Disseminated TB was the most frequent complication (30, 34.1%) followed by acute respiratory failure (23, 26.1%) and pleural empyema (6, 6.8%). In-hospital and 30-days mortality in complicated patients were 9/65 (13.8%) and 10/65 (15.4%), respectively. In-hospital mortality was significantly higher in patients with > 1 versus (VS) 1 complication (6, 31.6% VS 3, 6.5%, p = 0.02) without any difference in 1-month mortality (6, 31.6% VS 4, 9.8%, p = 0.06) between subgroups. Acute respiratory failure was the most lethal complication.

CONCLUSIONS

The study shows a substantial rate of complications in patients with a new diagnosis of TB associated to a significant short-term mortality. A prompt screen of complications at diagnosis is needed to improve short-term outcomes of these patients.

N-Acetylcysteine to Reduce Kidney and Liver Injury Associated with Drug-Resistant Tuberculosis Treatment

Background: New drug classes and regimens have shortened the treatment duration for drug-resistant tuberculosis, but adverse events (AEs) and organ toxicity remain unacceptably common. N-acetylcysteine (NAC) has demonstrated potential in reducing kidney and liver toxicity in other clinical settings, but efficacy in drug-resistant tuberculosis treatment has not been rigorously evaluated. Method: A randomized controlled trial was conducted at Kibong'oto Infectious Diseases Hospital in Tanzania to assess the efficacy of NAC in reducing AEs in patients undergoing rifampin-resistant pulmonary tuberculosis treatment. Participants received an all-oral standardized rifampin-resistant regimen alone, with NAC 900 mg daily, or NAC 900 mg twice daily for 6 months. AEs, severe AEs, and renal and liver toxicity were monitored monthly and classified according to the Risk, Injury, Failure, Loss, and End-stage kidney disease criteria and National Cancer Institute Common Terminology Criteria for Adverse Events. Incident ratios and Kaplan-Meier curves were employed to compare group event occurrences. Results: A total of 66 patients (mean age 47 ± 12 years; 80% male) were randomized into three groups of 22. One hundred and fifty-eight AEs were recorded: 52 (33%) in the standard treatment group, 55 (35%) in the NAC 900 mg daily group, and 51 (32%) in the NAC 900 mg twice-daily group (p > 0.99). Severe AEs were observed in four patients in the standard group, two in the NAC 900 mg daily group, and three in the NAC 900 mg twice-daily group. Renal toxicity was more prevalent in the standard treatment group compared to those that received NAC (45% vs. 23%; p = 0.058), with a shorter onset of time to toxicity (χ2 = 3.199; p = 0.074). Liver injury events were rare across all groups. Conclusion: Among Tanzanian adults receiving rifampin-resistant tuberculosis treatment, NAC did not significantly reduce overall AEs but demonstrated important trends in reducing renal toxicity.

Carbon dioxide regulates Mycobacterium tuberculosis PhoPR signaling and virulence

The Mycobacterium tuberculosis (Mtb) two-component regulatory system PhoPR is implicated in pH sensing within the macrophage because it is strongly induced by acidic pH both in vitro and the macrophage phagosome. The carbonic anhydrase (CA) inhibitor ethoxzolamide inhibits PhoPR signaling supporting the hypothesis that CO2 may also play a role in regulating PhoPR. Here, we show that increasing CO2 concentration induces PhoPR signaling, at both pH 7.0 and pH 5.7. At acidic pH 5.7, a normally strong inducer of PhoPR signaling, increasing CO2 from 0.5% to 5% further induces the pathway, showing CO2 acts synergistically with acidic pH to induce the PhoPR regulon. Based on these findings, we propose that PhoPR functions as a CO2 sensor. Mtb has three CA (CanA, CanB, and CanC), and using CRISPR interference knockdowns and gene deletion mutants, we assessed which CAs regulate PhoPR signaling and macrophage survival. We first examined if CA played a role in Mtb pathogenesis and observed that CanB was required for survival in macrophages, where the knockdown strain had ~1-log reduction in survival. To further define the interplay of CO2 and Mtb signaling, we conducted transcriptional profiling experiments at varying pH and CO2 concentrations. As hypothesized, we observed that the induction of PhoPR at acidic pH is dependent on CO2 concentration, with a subset of core PhoPR regulon genes dependent on both 5% CO2 and acidic pH for their induction, including expression of the ESX-1 secretion system. Transcriptional profiling also revealed core CO2-responsive genes that were differentially expressed independently of the PhoPR regulon or the acidic pH-inducible regulon. Notably, genes regulated by a second two-component regulatory system, TrcRS, are associated with adaptation to changes in CO2.

The Role of Inflammation in the Pathogenesis of Comorbidity of Chronic Obstructive Pulmonary Disease and Pulmonary Tuberculosis

The comorbid course of chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis is an important medical and social problem. Both diseases, although having different etiologies, have many overlapping relationships that mutually influence their course and prognosis. The aim of the current review is to discuss the role of different immune mechanisms underlying inflammation in COPD and pulmonary tuberculosis. These mechanisms are known to involve both the innate and adaptive immune system, including various cellular and intercellular interactions. There is growing evidence that immune mechanisms involved in the pathogenesis of both COPD and tuberculosis may jointly contribute to the tuberculosis-associated obstructive pulmonary disease (TOPD) phenotype. Several studies have reported prior tuberculosis as a risk factor for COPD. Therefore, the study of the mechanisms that link COPD and tuberculosis is of considerable clinical interest.

The role of neutrophil response in lung damage and post-tuberculosis lung disease: a translational narrative review

It is estimated that more than 150 million individuals alive in 2020 had survived tuberculosis (TB). A portion of this large population continues to experience chronic respiratory abnormalities, with or without symptoms, due to previous active pulmonary TB. This condition known as Post-TB Lung Disease (PTLD), involves a complex interaction between pathogen, host and environmental factors. These interactions are believed to drive a hyperinflammatory process in the lungs during active TB, resulting in tissue damage, which may lead to radiological sequelae, impaired pulmonary function, clinical symptoms, such as cough, dyspnea, hemoptysis, and respiratory infections. Such complications impose significant health, financial, and social burdens, which remain poorly understood and inadequately addressed by health care systems. Given the heterogeneity of immune cells and their products infiltrating the airways and the lung parenchyma during acute and chronic inflammation caused by Mycobacterium tuberculosis infection, it is evident that TB immunopathology is multifactorial. Among the various components involved, neutrophils have recently emerged as critical contributors to the deleterious immune response against TB, leading to severe pulmonary damage. In this translational narrative review, we aim to summarize the role of neutrophils and their primary products - proteases (such as elastase), matrix metalloproteinases and neutrophils extracellular traps (NETs) - in pulmonary TB. We highlight new concepts and emerging evidence of neutrophil involvement during the active disease, translating these insights from "bench to bedside" to facilitate dialogue between fundamental researchers and clinical practitioners. Additionally, we present potential targets for future treatment strategies that could mitigate or even prevent PTLD.

Fluctuations in circulating cell-free mitochondrial and nuclear DNA copy numbers in blood plasma after anti-tuberculosis drug intake in patients with drug-susceptible tuberculosis

Biomarker research characterising the effect of anti-tuberculosis (TB) chemotherapy on systemic body response is still limited. In this study, we aimed to investigate fluctuations in circulating cell-free mitochondrial DNA (ccf-mtDNA) and circulating cell-free nuclear DNA (ccf-nDNA) copy number (CN) in blood plasma of patients with drug-susceptible TB (DS-TB) and to decipher factors related to these fluctuations. The results showed considerable changes in ccf-mtDNA CN in plasma samples before drug intake and 2 and 6 h afterwards, with high inter patient variability at each time point. Multivariate linear regression revealed that the dynamics of ccf-mtDNA CN was influenced by patients' age, ethambutol pharmacokinetics, and body-mass index (BMI); ethambutol exposure emerged as the most significant factor. Very low ccf-nDNA CN in all three time points with little variation was observed; none factors were strongly associated with ccf-nDNA. In conclusion, our study revealed the effect of anti-TB chemotherapy, age and BMI on acute changes in circulating ccf-mtDNA CN in blood plasma and highlighted the systemic, mitochondria-related effects of ethambutol in patients with TB. Further studies with larger cohorts are needed to understand the biological relevance of ccf-DNA in patients with TB and to validate its application in TB treatment monitoring.

Long-term evaluation in BALBc mice of a triple mutant of Mycobacterium bovis and the Bacillus Calmette-Guérin as potential vaccines against bovine tuberculosis

There is currently no commercial vaccine available against bovine tuberculosis (bTB). Mycobacterium bovis is the primary causative agent of bTB and is closely related to Mycobacterium tuberculosis, the pathogen responsible for human TB. Despite their limitations, mouse models are invaluable in early vaccine development due to their genetic diversity, cost-effectiveness, and the availability of research tools. Researchers have tested many TB vaccines in mice, although few specifically target bTB. In this study, we developed a mutant strain of M. bovis lacking the esxA, esxB genes and the virulence gene fbpA to evaluate its long-term protective efficacy in BALB/c mice. We also analysed local immune responses and compared the results with those of BCG vaccination. Both BCG and the triple mutant strain Mb303ΔesxABΔfbpA demonstrated protection in BALB/c mice against M. bovis challenge, as evidenced by reduced bacterial lung loads. A histopathological analysis revealed the absence of ZN+ bacteria in the lungs of M. bovis-challenged mice vaccinated with BCG. In addition, mice vaccinated with the triple mutant exhibited a higher profile of protective immune CD4 + T cells in the lungs than those vaccinated with BCG. Notably, there was a negative correlation between the bacterial loads in the lungs of mice and the T cell subpopulations CD4 +KLRG1-PD1 +CCR7 + and CD4 +KLRG1-CXCR3 + , indicating that these T cell phenotypes are potential markers of protection against bTB. These findings indicate that the Mb303ΔesxABΔfbpA strain provides long-term protection against bTB. Furthermore, the results reaffirm the potential of BCG as a vaccine against this disease.

Nutritional Factors and Food and Nutrition Insecurity in Patients with Tuberculosis

Background/Objectives: Brazil has a high incidence of new tuberculosis cases influenced by socioeconomic factors. Inadequate housing, limited access to health services, and insufficient food increase vulnerability to the disease. This study aimed to identify sociodemographic, nutritional, and anthropometric factors associated with active pulmonary tuberculosis. Methods: This case-control study was conducted at the tuberculosis (TB) Referral Hospital in São Luís, Maranhão, Brazil, from 2022 to 2024. It included 65 patients with active pulmonary TB and 73 comparison individuals. Sociodemographic and nutritional data were collected using an adapted semi-quantitative questionnaire with 77 items, based on the validated ELSA-BRASIL questionnaire for adults, to assess the consumption of calcium, phosphorus, iron, zinc, vitamin B3, vitamin B6, vitamin C, vitamin E, and vitamin D. The Brazilian Food Insecurity Scale (EBIA) was used to analyze food and nutrition security or insecurity. Body Mass Index (BMI) was calculated based on weight and height measurements. Results: The TB patients were predominantly men (73.8%), of mixed ancestry (69.4%), with low education levels (73.4%), and had a mean age of 39 years. Furthermore, 26.2% of the patients were underweight, and 64% experienced some degree of food and nutrition insecurity. The variables education level, vitamin D, and BMI were associated with the outcome in the final model. Conclusions: The study identified a high prevalence of food insecurity and vitamin E deficiency in individuals with active tuberculosis, in addition to associating low educational levels, inadequate vitamin D intake, and overweight with a higher risk of TB. Although it has limitations, such as the cross-sectional design and sample size, the results highlight the importance of these determinants and point to the need for longitudinal research to confirm and expand the evidence.

A bacterial effector manipulates host lysosomal protease activity-dependent plasticity in cell death modalities to facilitate infection

Crosstalk between cell death programs confers appropriate host anti-infection immune responses, but how pathogens co-opt host molecular switches of cell death pathways to reprogram cell death modalities for facilitating infection remains largely unexplored. Here, we identify mammalian cell entry 3C (Mce3C) as a pathogenic cell death regulator secreted by Mycobacterium tuberculosis (Mtb), which causes tuberculosis featured with lung inflammation and necrosis. Mce3C binds host cathepsin B (CTSB), a noncaspase protease acting as a lysosome-derived molecular determinant of cell death modalities, to inhibit its protease activity toward BH3-interacting domain death agonist (BID) and receptor-interacting protein kinase 1 (RIPK1), thereby preventing the production of proapoptotic truncated BID (tBID) while maintaining the abundance of pronecroptotic RIPK1. Disrupting the Mce3C-CTSB interaction promotes host apoptosis while suppressing necroptosis with attenuated Mtb survival and mitigated lung immunopathology in mice. Thus, pathogens manipulate host lysosomal protease activity-dependent plasticity in cell death modalities to promote infection and pathogenicity.

The prevalence and pattern of post tuberculosis lung disease including pulmonary hypertension from an Australian TB service; a single-centre, retrospective cohort study

INTRODUCTION

Post Tuberculosis Lung Disease (PTLD) is increasingly recognised as a significant cause of morbidity internationally, but has not been described in an Australian setting. We aimed to determine the prevalence of PTLD among adult TB survivors from an Australian TB service and describe the pattens of lung function abnormalities and pulmonary disease, including pulmonary hypertension.

METHODS

We conducted a single-centre retrospective cohort study in Sydney, Australia, including all adults who successfully completed TB treatment between January 2013 and December 2022. Baseline characteristics, post treatment pulmonary function, and thoracic computed tomography (CT) data were analysed to determine the prevalence and patterns of PTLD, defined as any lung function and/or radiological abnormality attributable to TB.

RESULTS

Among 119 confirmed TB patients (mean age 46 ± 21 years, 61% males) PTLD was identified in 81/119 (68%). Pulmonary function testing was available for 51/119 (43%), of whom 38/51(75%) exhibited abnormalities. Obstructive deficits were found in 25/51 (49%), restrictive deficits in 11/51 (22%), and impaired gas transfer capacity in 26/51 (51%). Chest CT scans were completed in 76/119 (64%), with 70/76 (92%) demonstrating significant abnormalities, including pulmonary fibrosis 43/76 (57%), bronchiectasis 22/76 (29%), and emphysema 11/76 (15%). Pulmonary hypertension was suspected in 52/76 (68%) patients based on radiological findings.

CONCLUSION

Despite successful treatment, PTLD was frequently observed among our cohort of Australian TB survivors. Further research into optimal screening practices to diagnose chronic pulmonary diseases and pulmonary hypertension could provide opportunities for earlier intervention and management.

Development of chronic obstructive pulmonary disease after a tuberculosis episode in a large, population-based cohort from Eastern China

BACKGROUND

Although smoking is considered the primary cause of chronic obstructive pulmonary disease (COPD), there is a growing realization that there may be important secondary risk factors. Tuberculosis may lead to lung impairment; however, whether residual lung damage results in clinically significant, long-term outcomes, independent of smoking, has not been well studied. We aimed to investigate the association between tuberculosis and the subsequent development of COPD using a large, population-based cohort study.

METHODS

We conducted a longitudinal cohort study within the Chinese Electronic Health Records Research in Yinzhou study between 2009 and 2021. We followed participants free of COPD at the beginning of the study, and investigated whether previous or current tuberculosis was an important risk factor. Tuberculosis was recorded based on the Chinese National Disease Reporting system which includes all diagnosed cases at the city, provincial and national levels. We assessed the relationship between tuberculosis and COPD using multivariable survival models, adjusting for demographic and lifestyle characteristics, education level, comorbidities and use of medications.

RESULTS

Among 477 046 participants, 198 882 were eligible for inclusion in our analysis. In a multivariable model, pulmonary tuberculosis and all tuberculosis were associated with a 2.57-fold [95% confidence interval (CI), 2.31-2.87)] and 1.67-fold (95% CI, 1.48-1.90) increased COPD risk, respectively. Stronger associations of pulmonary tuberculosis and all tuberculosis with COPD were seen in participants who were elderly, or with lower body mass index or education level (Pinteraction<0.001). People with tuberculosis were at an increased risk of COPD if they were current smokers [adjusted hazard ratio (aHR), 1.40; 95% CI, 1.02-1.93] or non-smokers (aHR, 1.72; 95% CI, 1.50-1.98).

CONCLUSIONS

Persons who developed tuberculosis were at much greater risk of developing COPD, even accounting for smoking and other potential confounders.

Allergic Bronchopulmonary Aspergillosis in Patients With Prior Pulmonary Tuberculosis: A Study on the Burden, Clinic-Radiological Features, Treatment Outcomes and Comparison With Chronic Pulmonary Aspergillosis and Post-Tubercular Lung Disease Patients

BACKGROUND

Post-tuberculosis lung disease (PTLD) is a precursor to Aspergillus-related lung diseases. While Chronic Pulmonary Aspergillosis (CPA) has been extensively studied in the background of tuberculosis, Allergic Bronchopulmonary Aspergillosis (ABPA) has been reported sporadically with limited information on its prevalence, clinical-radiological features, and treatment outcomes.

OBJECTIVE

This study, conducted in a high TB burden setting, aimed to address this knowledge gap by systematically evaluating ABPA in PTLD patients.

METHODS

This retrospective cohort study screened PTLD patients presenting with respiratory or constitutional symptoms persisting for more than 3 months. The objective was to report the prevalence, clinical-radiological-laboratory data, and outcomes of ABPA-PTLD compared to a cohort of CPA (CPA-PTLD) and patients with PTLD (PTLD only).

RESULTS

Out of a total of 1012 PTLD patients, ABPA was seen in 2.27%, CPA in 20.75% and Aspergillus sensitization in 0.7%. ABPA patients primarily presented with breathlessness (91.3%) and cough (82.6%) while haemoptysis (43.5%), weight loss (13%), and anorexia (21.7%) were also observed, albeit less commonly than in CPA-PTLD. Bronchiectasis (100%) and nodules (87%) were more frequent in ABPA-PTLD patients, whereas consolidation (21.7%), cavities (30.4%), pleural thickening (8.7%), and 'fungal ball' (9.1%) were also seen, although less commonly than in CPA-PTLD. Most patients received azoles (78%) as first-line therapy, with symptomatic improvement (partial/complete) observed in ~78%.

CONCLUSION

ABPA may occur in PTLD patients, with specific clinical (e.g., haemoptysis) and radiological (e.g., cavity and fungal ball) features uncommon in other types of ABPA, but resembling other PTLD conditions. Future studies should focus on identifying differences in the natural course and appropriate treatment paradigms of ABPA-PTLD patients compared to ABPA occurring in asthma and cystic fibrosis patients.

Hypercoagulability in Tuberculosis: Pathophysiological Mechanisms, Associated Risks, and Advances in Management-A Narrative Review

Tuberculosis (TB) induces a hypercoagulable state characterized by systemic inflammation, endothelial dysfunction, and alterations in the coagulation and fibrinolytic pathways. This review explores the pathophysiological mechanisms underlying hypercoagulability in TB, including increased pro-inflammatory cytokine release, endothelial damage, platelet activation, and reduced anticoagulant and fibrinolytic activity. These factors contribute to an elevated risk of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), which complicate TB prognosis and treatment. The potential role of adjunctive anti-inflammatory therapies, such as vitamin D, NSAIDs, corticosteroids, and anti-platelet agents, is highlighted as a strategy to mitigate systemic inflammation and reduce thrombotic risks in patients with TB. The challenges of anticoagulation therapy, particularly in managing the interactions between anti-TB medications and traditional anticoagulants, are discussed, along with the potential of novel oral anticoagulants (NOAs) as alternatives. We also address therapy of hypercoagulability in TB within resource-limited settings which requires low-cost diagnostics, accessible anticoagulation options, adjunctive therapies, and preventive strategies integrated into existing healthcare systems. Effective risk stratification and individualized management strategies are vital for reducing the morbidity and mortality associated with thrombotic complications in TB.

Development of a Vaccine Candidate Based on Surface-Displayed Particles of Mycobacterium tuberculosis from the MTB39A Protein

Tuberculosis (TB), a human and animal disease caused by Mycobacterium tuberculosis (M.tb), has the highest global mortality rate after coronavirus disease 2019 (COVID-19) and poses a major public health threat globally. Since 1890, vaccine candidates for various forms of TB have been developed for different age groups, but these vaccine candidates have not provided intended protection in adolescents and adults in clinical trials. To help prevent and control the spread of TB, the development of a safe and effective TB vaccine is imperative. The MTB39A protein and the molecular adjuvant MTB32C protein were expressed by an insect-baculovirus expression system, and the recombinant baculovirus surface-displayed particles were evaluated for their immunogenicity in BALB/c mice and calves. The results showed that the rvAc-71CA/rvAc-MTB39A recombinant baculovirus surface-displayed particles exhibited good immunogenicity in mice and calves and could be further developed as potential candidates.

Potential of Mycobacterium tuberculosis Type II NADH-Dehydrogenase in Antitubercular Drug Discovery

The type II NADH-dehydrogenase enzyme in Mycobacterium tuberculosis plays a critical role in the efficient functioning of the oxidative phosphorylation pathway. It acts as the entry point for electrons in the electron transport chain, which is essential for fulfilling the energy requirements of both replicating and nonreplicating mycobacterial species. Due to the absence of the type II NADH-dehydrogenase enzyme in mammalian mitochondria, targeting the type II NADH-dehydrogenase enzyme for antitubercular drug discovery could be a vigilant approach. Utilizing type II NADH-dehydrogenase inhibitors in antitubercular therapy led to bactericidal response, even in monotherapy. However, the absence of the cryo-EM structure of Mycobacterium tuberculosis type II NADH-dehydrogenase has constrained drug discovery efforts to rely on high-throughput screening methods, limiting the use of structure-based drug discovery. Here, we have delineated the literature-reported Mycobacterium tuberculosis type II NADH-dehydrogenase inhibitors and the rationale behind selecting this specific enzyme for antitubercular drug discovery, along with shedding light on the architecture of the enzyme structure and functionality. The gap in the current research and future research direction for TB treatment have been addressed.

Identification of Post-Tuberculosis Lung Function Impairment Early during the Course of Treatment

Tuberculosis (TB) is a leading cause of morbidity and mortality and an important contributory factor to chronic lung disease. TB-associated permanent lung damage manifests with varying levels of respiratory disability long after TB has been successfully treated, which is a condition known as post-TB lung disease (PTLD). This study assessed whether lung function impairment associated with PTLD occurs early during TB treatment. Using a cross-sectional design, we enrolled newly diagnosed adult TB patients aged ≥18 years who had received anti-TB medication for ≥2 months from a large treatment center in northern Nigeria. We used spirometry and the Global Lung Initiative 2012 reference equations for African Americans to assess and characterize lung function for enrolled participants (N = 94). The median age (range) of participants was 34 (18-72) years. Approximately 5.3% (n = 5) of participants exhibited features of abnormal lung function, 4.2% (n = 4) showed features of obstructive lung abnormality, and 1.1% (n = 1) showed restrictive lung abnormality. Compared with historical patients recruited ≥6 months after TB treatment in the same center, our participants had significantly lower forced expiratory volume in one second and forced vital capacity values. Our findings suggest an opportunity for early intervention for primary and secondary prevention of PTLD to reduce the impact of severe respiratory impairment.

Characteristics and outcomes of in-hospital patients with Covid-19 and history of tuberculosis: a matched case-control from the Brazilian Covid-19 Registry

BACKGROUND

The Covid-19 pandemic caused a negative impact on other infectious diseases control, prevention, and treatment. Consequently, low and middle-income countries suffer from other endemic diseases, such as tuberculosis. This study was designed to compare Covid-19 manifestations and outcomes between patients with previously treated tuberculosis and controls without this condition.

METHODS

We performed a matched case-control study drawn from the Brazilian Covid-19 Registry data, including in-hospital patients aged 18 and over with laboratory-confirmed Covid-19 from March 1, 2020, to March 31, 2022. Cases were patients with a past history of tuberculosis. Controls were Covid-19 patients without a tuberculosis history. Patients were matched by hospital, sex, presence of HIV, and number of comorbidities, with a 1:4 ratio.

RESULTS

Of 13,636 patients with laboratory-confirmed diagnoses of Covid-19 enrolled in this study, 80 had a history of tuberculosis. Statistical differences in history of chronic pulmonary obstructive disease (15% vs. 3.2%), psychiatric disease (10% vs. 3.5%,), chronic kidney disease (11.2% vs. 2.8%), and solid-organ transplantation; (5% vs. 0.9%, p < 0.05 for all) were higher in patients with a past history of tuberculosis. Prior use of inhalatory medications (5% vs. 0.6%,), oral corticoids (8.8% vs. 1.9%), immunosuppressants (8.8% vs. 1.9%,) and the use of illicit drugs were more common in the case group (6.2% vs. 0.3% p < 0.05for all). There were no significant differences in in-hospital mortality, mechanical ventilation, need for dialysis, and ICU admission.

CONCLUSIONS

Patients with a history of tuberculosis infection presented a higher frequency of use of illicit drugs, chronic pulmonary obstructive disease, psychiatric disease, chronic kidney disease, solid-organ transplantation, prior use of inhalatory medications, oral corticoids, and immunosuppressants. The outcomes were similar between cases and controls.

Immunopathology in human tuberculosis

Mycobacterium tuberculosis (M.tb) is a bacterial pathogen that has evolved in humans, and its interactions with the host are complex and best studied in humans. Myriad immune pathways are involved in infection control, granuloma formation, and progression to tuberculosis (TB) disease. Inflammatory cells, such as macrophages, neutrophils, conventional and unconventional T cells, B cells, NK cells, and innate lymphoid cells, interact via cytokines, cell-cell communication, and eicosanoid signaling to contain or eliminate infection but can alternatively mediate pathological changes required for pathogen transmission. Clinical manifestations include pulmonary and extrapulmonary TB, as well as post-TB lung disease. Risk factors for TB progression, in turn, largely relate to immune status and, apart from traditional chemotherapy, interventions primarily target immune mechanisms, highlighting the critical role of immunopathology in TB. Maintaining a balance between effector mechanisms to achieve protective immunity and avoid detrimental inflammation is central to the immunopathogenesis of TB. Many research gaps remain and deserve prioritization to improve our understanding of human TB immunopathogenesis.

Imperfect wound healing sets the stage for chronic diseases

Although the age of the genome gave us much insight about how our organs fail with disease, it also suggested that diseases do not arise from mutations alone; rather, they develop as we age. In this Review, we examine how wound healing might act to ignite disease. Wound healing works well when we are younger, repairing damage from accidents, environmental assaults, and battles with pathogens. Yet, with age and accumulation of mutations and tissue damage, the repair process can devolve, leading to inflammation, fibrosis, and neoplastic signaling. We discuss healthy wound responses and how our bodies might misappropriate these pathways in disease. Although we focus predominantly on epithelial-based (lung and skin) diseases, similar pathways might operate in cardiac, muscle, and neuronal diseases.

Hepatoprotective effect of diammonium glycyrrhizinate in the treatment of pulmonary tuberculosis

Objective

To explore the hepatoprotective effect of diammonium glycyrrhizinate (DG) in the treatment of pulmonary tuberculosis.

Methods

This is a retrospective analysis of clinical data of 113 patients with pulmonary tuberculosis, admitted to The First People's Hospital of Linping District from March 2020 to December 2022. Among them, 55 patients who received conventional anti-tuberculosis treatment (2HRZE/4HR) alone were assigned to the Routine group, while 58 patients who received anti-tuberculosis treatment combined with DG treatment were assigned to the DG group. Treatment efficacy, incidence of liver injury, levels of total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and adverse reactions were assessed in the two groups.

Results

The total efficacy of treatment was significantly higher, and the incidence of liver injury was significantly lower in the DG group compared to the Routine group (P<0.05). After the treatment, the levels of TBIL, ALT, and AST in both groups significantly increased, and were significantly lower in the DG group than in the Routine group (P<0.05). There was no significant difference in the incidence of adverse reactions between the groups (P>0.05).

Conclusions

In the treatment of pulmonary tuberculosis, combining DG with conventional anti-tuberculosis regimen can improve overall intervention effect, reduce incidence of liver injury, and alleviate its degree.

The role of antibiotic-derived mycobacterial vesicles in tuberculosis pathogenesis

Pulmonary tuberculosis (TB) causes progressive and irreversible damage to lung tissue, a damage that may not fully resolve after treatment. Mycobacterial vesicles (MVs), which are poorly understood, may contribute to TB pathology. This study investigated the effects of stress, such as treatment with conventional TB antibiotics rifampicin, isoniazid, ethambutol, or treatment with an antimycobacterial peptide (NZX), on mycobacterial vesiculation. Stress from minimal inhibitory concentrations of antibiotics, or peptide all increased MV formation. Electron microscopy and lipid profiling revealed that these vesicles, about 40 nm in size, were released from the bacterial inner membrane and consisted of apolar lipids. Using mass spectrometry, the study identified key differences in MVs protein cargo dependent on the antibiotic used, especially with ethambutol-induced MVs that contained proteins from several mycobacterial pathways. Additionally, toxicology analysis using different concentrations of MVs on primary human macrophages and the monocytic cells indicated that MVs from the different treatments were not toxic to human cells, however induced specific inflammatory profiles. In conclusion, this study identified mycobacterial vesicles to be a potential contributor to tuberculosis pathology.

Increased active pulmonary tuberculosis risk from sharing bong of cannabis: a case-control study from Thailand

Introduction

Tuberculosis (TB) is a chronic lung disease caused by Mycobacterium tuberculosis. Tobacco smoking and sharing of instruments have been reported to increase TB risk. In 2022, cannabis was legalized in Thailand. To address for the potential increase in cannabis use after legalization and the reported increased TB risk associated with cannabis usage, we aimed to estimate the odds ratio and population-attributable fraction (PAF) of different types of cannabis use.

Materials and methods

A matched case-control study was conducted in the Songkhla Province of Southern Thailand in 2023. Face-to-face interviews were conducted to collect information on cannabis consumption. Multivariate logistic regression was performed to estimate the odds ratios representing TB risk from the independent variables. PAF was also calculated to compare the public health impacts of the variables.

Results

Among the 148 TB cases and 117 healthy controls, we observed lower socioeconomic status and higher proportions of tobacco and alcohol use in these cases. Eleven percent of the controls were current cannabis users, while nearly 19% had ever experienced cannabis use. The proportions of ever-used, smoked, and shared cannabis use were significantly higher in these cases. After adjusting for covariates, the best-fit model showed an odds ratio of 4.22 (95% confidence interval: 1.47-12.07) for smoking and sharing a bong of cannabis. No statistical significance was found for the other types of consumption. PAF of smoked and shared bongs of cannabis was 12.16, which was slightly lower than that found in smoking tobacco (12.62).

Conclusion

Increased numbers of cannabis users, especially shared smokers, may have an impact on TB risk in lower-middle-income countries, where TB is already highly prevalent.

Association Between Indices of Peripheral Blood Inflammation and Cavitary Pulmonary Tuberculosis

Objective

To explore inflammation markers of C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammatory index (SII), and systemic inflammatory response index (SIRI) in the differential diagnosis of cavitary pulmonary tuberculosis (PTB) from non-cavitary PTB.

Methods

This retrospective study included 1233 patients with PTB, 518 patients were diagnosed with cavitary PTB as case group, while 715 patients which diagnosed with non-cavitary PTB were selected as control group. The clinical data of patients was collected and the levels of inflammation indices were measured. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnosis and analysis of selected indices. Logistic regression analysis was performed to evaluate the factors associated with cavitary PTB.

Results

The CRP, NLR, MLR, PLR, SII, and SIRI in the case group were significantly higher than those in the controls (all p<0.001). When cavitary PTB was taken as the endpoint, the optimal diagnostic thresholds of CRP was 35.365 (area under the ROC curve (AUC)=0.601), NLR was 5.740 (AUC=0.595), MLR was 0.525 (AUC=0.577), PLR was 198.255 (AUC=0.602), SII was 1252.045 (AUC=0.628), and SIRI was 2.095 (AUC=0.605), respectively. Logistic regression analysis showed that gender, CRP, PLR, and SIRI were the independent risk factors for cavitary PTB. The sensitivity of the combination of the three indices (CRP+PLR, CRP+SIRI, PLR+SIRI, and CRP+PLR+SIRI) were higher than those of the CRP, PLR, and SIRI.

Conclusion

CRP, PLR, and SIRI levels were associated with an increased likelihood of cavitary PTB. The combined detection of CRP, PLR, and SIRI is promising as a screening marker and may be useful for ruling out PTB with cavitary.

Clinical effect of MRZE chemotherapy combined with cluster nursing intervention in the treatment of patients with pulmonary tuberculosis and its influence on the levels of inflammatory factors and CT signs

The study aimed to analyze the clinical effect of MRZE chemotherapy combined with cluster nursing intervention and treatment of pulmonary tuberculosis patients and its influence on CT signs. A total of 94 patients treated in our hospital from March 2020 to October 2021 were selected as the research object. Both groups were treated with MRZE chemotherapy regimen. Patients in the control group received routine nursing mode on this basis, and patients in the observation group received cluster nursing on the basis of the control group. The clinical efficacy, adverse reactions, compliance and nursing satisfaction, detection rate of immune function pulmonary oxygen index and pulmonary function CT signs and the level of inflammatory factors before and after nursing were compared between the two groups. The total effective rate of the observation group was significantly higher than that of the control group. The compliance rate and nursing satisfaction of the observation group were significantly higher than those of the control group. The differences of adverse reactions between the observation and control groups were statistically significant. After nursing, the scores of tuberculosis prevention and control of tuberculosis infection route, tuberculosis symptoms, tuberculosis policy and tuberculosis infection awareness in the observation group were significantly higher than those in the control group, and the differences were statistically significant. MRZE chemotherapy combined with cluster nursing intervention model for pulmonary tuberculosis patients can effectively improve the treatment compliance and nursing satisfaction of patients, and it is worthy of clinical promotion and application.

Association between dust exposure and lung function levels in steelworkers: mediation analysis of inflammatory biomarkers

PURPOSE

This investigation aimed to examine the mediating effect of inflammatory biomarkers on the relationship between dust exposure and lung function levels among steelworkers.

METHODS

The study comprised 2,315 front-line workers employed at an iron and steel company in Tangshan, who underwent occupational health assessments through cluster sampling. Demographic and lifestyle data were collected via a self-administered questionnaire, while physical examinations measured parameters such as height and weight. Lung function was assessed using a portable pulmonary function tester (CHEST). Blood cell counts were uniformly analyzed using a Mindray fully automated biochemistry analyzer (BS-800). Inflammatory biomarkers, including leukocyte count, neutrophil count, lymphocyte count, and platelet count, were assessed, and the neutrophil-to-lymphocyte ratio and systemic immune inflammation index were computed. Generalized linear models and Spearman rank correlation analyses were employed to explore the interplay among dust exposure, inflammatory biomarkers, and alterations in lung function. A mediation analysis model was constructed to elucidate how inflammatory biomarkers mediate the relationship between dust exposure and lung function levels.

RESULTS

After adjusting for covariates, dust exposure was significantly associated with reduced lung function levels, with statistically significant differences observed between dust-exposed and non-exposed groups across various lung function indicators (P < 0.001). In the dust-exposed group, inflammatory biomarkers were elevated, showing significant correlations with FVC and FEV1 (P < 0.05). However, the correlation between FEV1/FVC and various inflammatory biomarkers was insignificant (P > 0.05). Mediation analysis revealed that white blood cells and neutrophils partially mediated the association between dust exposure and FVC, with proportions of 1.75% and 1.09%, respectively. Similarly, white blood cells, neutrophils, and the systemic immune inflammation index partially mediated the association between dust exposure and FEV1, with proportions of 1.15%, 0.82%, and 0.82%, respectively.

CONCLUSION

In conclusion, dust exposure poses a risk for decreased lung function levels. Inflammatory biomarkers derived from blood cells offer a valuable and easily obtainable means of identifying changes in lungfunction levels. Among these biomarkers, white blood cells, neutrophils, and the systemic immune inflammation index significantly mediate the association between dust exposure and lung function levels, although further exploration is needed to understand their underlying mechanisms.

The diagnostic value of hydroxyproline combined with tuberculosis infection T lymphocyte spot assay in pulmonary tuberculosis

Background

Tuberculosis (TB) is an infectious disease which has long threatened human health, and new molecular diagnostic markers for its diagnosis are urgently needed. The study was designed to analyze the expression of hydroxyproline (HYP) in different specimens of pulmonary TB (PTB) and assess its auxiliary diagnostic value alone or in combination with the TB infection T lymphocyte spot assay (TSPOT.TB).

Methods

According to the inclusion criteria, 43 healthy controls (HCs) and 39 patients with nontuberculous general respiratory diseases were included as the respiratory control (RC) group, while 42 patients with newly treated TB were included as the PTB group. The expression of HYP in serum, urine, and bronchoalveolar lavage fluid (BALF) was detected with a HYP detection kit. Correlation analysis was used to detect the correlation of HYP and clinical indicators. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity and specificity of HYP in diagnosing TB, both when used alone and in combination with TSPOT.TB.

Results

The expression of HYP in serum of patients with TB was significantly increased as compared to that in controls (P=0.03), but there was no significant difference in the expression of HYP in urine (P>0.05). Compared with the general pneumonia control group, the expression of HYP in BALF of the PTB group was significantly increased (P<0.001). HYP expression in serum was positively correlated with C-reactive protein (CRP) level (r=0.4661, P=0.002), neutrophil (r=0.3338, P=0.03) and monocyte count (r=0.3462, P=0.02), and was negatively correlated with serum albumin expression (r=-0.3575, P=0.02). The expression of HYP in urine was positively correlated with neutrophil count (r=0.3508, P=0.02), neutrophil percentage (r=0.3804, P=0.047), and monocyte count (r=0.3263, P=0.04) but was negatively correlated with serum albumin expression (r=-0.4031, P=0.008). The expression of HYP in BALF was positively correlated with CRP (r=0.3652, P=0.02) but not with other indexes (P>0.05). ROC curve analysis indicated that the sensitivity, specificity, and area under the curve (AUC) of blood HYP were 66.67%, 72.09%, and 0.6481, respectively, while those of its combined diagnosis with TSPOT.TB were 78.57%, 96.77%, and 0.8690, respectively. The sensitivity, specificity, and AUC of HYP in BALF were 67.74%, 64.29%, and 0.7435, respectively, while those of its combined diagnosis with TSPOT.TB were 78.59%, 93.55%, and 0.8606, respectively.

Conclusions

The expression of HYP in the serum and BALF of patients with PTB was higher than that of control group, and the expression of HYP was correlated with some clinical indicators. HYP demonstrated good sensitivity and specificity for the primary screening of PTB and higher sensitivity and specificity in the diagnosis of HYP when combined with TSPOT.TB. It may thus have certain value for auxiliary diagnosis in clinic.

Implementation of spirometry screening for post-tuberculosis lung disease (PTLD) among adolescents and adults enrolled within the National Tuberculosis Control Program of Carmelo Hospital in Chókwè District, Mozambique: A hybrid type III effectiveness-implementation study protocol

BACKGROUND

Despite receiving adequate treatment, many tuberculosis (TB) survivors are left with post-tuberculosis complications, possibly due to lung tissue damage incurred during the active period of the disease. Current TB programs worldwide deliver quality care throughout the course of active TB treatment, yet often fail to provide organized follow-up once treatment ends. Post-tuberculosis lung disease (PTLD) is a prominent, yet underrecognized cause of chronic lung disease, managed similarly to chronic respiratory diseases with pharmacotherapy and/or personalized pulmonary rehabilitation interventions. Basic pulmonary rehabilitation packages for people finishing TB treatment are still lacking in low- and middle-income countries (LMICs). We offer a study protocol to evaluate the implementation of spirometry and symptom screening for PTLD among people who have completed TB treatment in a rural district in Mozambique.

METHODS

The overall objective of this study is to evaluate the introduction of a new screening program that utilizes symptom screening and spirometry for diagnosing PTLD among adolescents and adults that have completed TB treatment. This research protocol consists of three complementary components: 1) assessing the prevalence of PTLD among patients enrolled in the National TB Control Program (NTCP) at Carmelo Hospital (CHC) in Chókwè District, Mozambique; 2) evaluating anticipated implementation outcomes through the identification of the site-, provider-, and individual-level determinants that either facilitate or hinder the successful adoption, implementation, and maintenance of the spirometry screening program, and 3) evaluating the real-time implementation outcomes/processes in order to provide practical evidence-based key indicators of successful implementation of the spirometry screening program.

DISCUSSION

Providing well-organized, evidence-based care for individuals with a history of TB who are experiencing symptoms of PTLD can relieve chronic respiratory issues, enhance quality of life, and potentially lower the risk of further pulmonary infections, including recurrent TB. However, there is a significant gap in the literature regarding the implementation of best practices of HIV and TB health services delivery. Addressing this gap could assist Mozambique in improving diagnosis, treatment, and continuity of care for people formerly living with TB. The insights from this study will help decision-makers improve spirometry screening coverage, enhance intervention effectiveness, and translate our findings to evidence-based programming.

TRIAL REGISTRATION

ISRCTN92021748 retrospectively registered.

Development and validation of a nomogram for predicting COPD: A nationwide population-based study in South Korea

Chronic obstructive pulmonary disease (COPD) remains a significant global health burden exacerbated by tobacco smoking, occupational exposure, and air pollution. COPD is one of the top 3 causes of death worldwide. In South Korea, the COPD burden is expected to increase due to ongoing exposure to risk factors and the aging population. COPD is extensively underdiagnosed or underestimated, owing to a lack of public awareness. This study aimed to develop and validate a nomogram for COPD by using national data to promote early diagnosis and intervention. This study drew on a dataset from the 7th Korea National Health and Nutrition Examination Survey from 2016 to 2018, including 10,819 subjects aged 40 years or older with spirometry results. Influence of demographic, socioeconomic, and health-related factors on the incidence. Multivariable logistic regression was used to identify the significant predictors of the nomogram. The nomogram was validated using receiver operating characteristic curves, calibration plots, and concordance index (C-index). Internal validation was performed by bootstrapping. In the final analysis, 1059 (14.0%) participants had COPD. Key risk factors associated with increased COPD risk included being male, aged 70 and older, lower educational level, living in a rural area, current smoking status, underweight, and history of tuberculosis and asthma. The area under the curve (AUC) of the model was 0.822 (95% CI: 0.810-0.832), indicating that the nomogram has a high ability to identify COPD. The nomogram demonstrated solid predictive performance, as confirmed by calibration plots with a C-index (of 0.822) for the validation set with 1000 bootstrap samples. In conclusion, we developed a tool for the early detection of COPD with good properties in primary care settings, without spirometry. Appropriate and early diagnosis of COPD can have a crucial impact on public health.

The Clinical Characteristics, Treatment and Prognosis of Tuberculosis-Associated Chronic Obstructive Pulmonary Disease: A Protocol for a Multicenter Prospective Cohort Study in China

Background

Tuberculosis and chronic obstructive pulmonary disease (COPD) are significant public health challenges, with pulmonary tuberculosis recognized as a pivotal risk factor for the development of COPD. Tuberculosis-associated COPD is increasingly recognized as a distinct phenotype of COPD that potentially exhibits unique clinical features. A thorough understanding of the precise definition, clinical manifestations, prognosis, and most effective pharmacological strategies for tuberculosis-associated COPD warrants further investigation.

Methods

This prospective, observational cohort study aims to enroll over 135 patients with tuberculosis-associated COPD and 405 patients with non-tuberculosis-associated COPD, across seven tertiary hospitals in mainland China. The diagnosis of tuberculosis-associated COPD will be established based on the following criteria: (1) history of pulmonary tuberculosis with standard antituberculosis treatment; (2) suspected pulmonary tuberculosis with radiological evidence indicative of tuberculosis sequelae; (3) no definitive history of pulmonary tuberculosis but with positive interferon-gamma release assay results and radiological signs suggestive of tuberculosis. At baseline, demographic information, medical history, respiratory questionnaires, complete blood count, interferon-gamma release assays, medications, spirometry, and chest computed tomography (CT) scans will be recorded. Participants will be followed for one year, with evaluations at six-month intervals to track the longitudinal changes in symptoms, treatment, lung function, and frequencies of COPD exacerbations and hospitalizations. At the final outpatient visit, additional assessments will include chest CT scans and total medical costs incurred.

Discussion

The findings of this study are expected to delineate the specific characteristics of tuberculosis-associated COPD and may propose potential treatment options for this particular phenotype, potentially leading to improved clinical management and patient outcomes.

Neural Networks Based Smart E-Health Application for the Prediction of Tuberculosis Using Serverless Computing

The convergence of the Internet of Things (IoT) with e-health records is creating a new era of advancements in the diagnosis and treatment of disease, which is reshaping the modern landscape of healthcare. In this paper, we propose a neural networks-based smart e-health application for the prediction of Tuberculosis (TB) using serverless computing. The performance of various Convolution Neural Network (CNN) architectures using transfer learning is evaluated to prove that this technique holds promise for enhancing the capabilities of IoT and e-health systems in the future for predicting the manifestation of TB in the lungs. The work involves training, validating, and comparing Densenet-201, VGG-19, and Mobilenet-V3-Small architectures based on performance metrics such as test binary accuracy, test loss, intersection over union, precision, recall, and F1 score. The findings hint at the potential of integrating these advanced Machine Learning (ML) models within IoT and e-health frameworks, thereby paving the way for more comprehensive and data-driven approaches to enable smart healthcare. The best-performing model, VGG-19, is selected for different deployment strategies using server and serless-based environments. We used JMeter to measure the performance of the deployed model, including the average response rate, throughput, and error rate. This study provides valuable insights into the selection and deployment of ML models in healthcare, highlighting the advantages and challenges of different deployment options. Furthermore, it also allows future studies to integrate such models into IoT and e-health systems, which could enhance healthcare outcomes through more informed and timely treatments.

Treatment Outcomes and Associated Influencing Factors Among Patients with Rifampicin-Resistant Tuberculosis: A Multicenter, Retrospective, Cohort Study in China

Objective

Rifampin-resistant tuberculosis (RR-TB) remains a serious global public health concern. We assessed treatment outcomes and associated influencing factors among RR-TB patients in China.

Methods

This research enrolled 1339 patients who started RR-TB treatment between May 2018 and April 2020 in China retrospectively. Data were collected from the electronic medical records. Multivariable logistic regression analysis was used to identify the influencing factors related to unfavorable outcomes.

Results

Of the 1339 RR-TB patients, 78.8% (1055/1339) achieved treatment success (cured or treatment completed), 5.1% (68/1339) experienced treatment failure, 1.1% (15/1339) died during treatment, 10.1% (135/1339) were lost to follow-up, and 4.9% (66/1339) were not evaluated. About 67.7% (907/1339) of patients experienced at least one adverse event (AE). The most common AE was hypohepatia (507/1339, 37.9%), followed by hyperuricemia (429/1339, 32.0%), anemia (368/1339, 27.5%), electrolyte disturbance (318/1339, 23.7%), peripheral neuritis (245/1339, 18.3%), and gastrointestinal reactions (203/1339, 15.2%). Multivariate analysis showed that age ≥60 years [adjusted odds ratio (aOR): 1.96, 95% confidence interval (CI): 1.39-2.77], national minority (aOR: 2.36, 95% CI: 1.42-3.93), smoking (aOR: 1.50, 95% CI: 1.10-2.04), cardiopathy (aOR: 2.90, 95% CI: 1.33-6.31), tumors (aOR: 9.84, 95% CI: 2.27-42.67), immunocompromise (aOR: 2.17, 95% CI: 1.21-3.91), re-treated TB (aOR: 1.46, 95% CI: 1.08-1.97), and experienced gastrointestinal reactions (aOR: 2.27, 95% CI: 1.52-3.40) were associated with unfavorable outcomes. Body mass index (BMI) ≥18.5 kg/m2, regimens containing bedaquiline and experienced adverse events (AEs) such as hypohepatia, leukopenia, peripheral neuritis, and optic neuritis were associated with favorable outcomes.

Conclusion

High rates of treatment success were achieved for RR-TB patients at tertiary tuberculosis hospitals in China. Age ≥60 years, national minority, smoking status, comorbidities, re-treated TB, and experienced gastrointestinal reactions were independent prognostic factors for unfavorable treatment outcomes.

Implications of progressive lung damage and post-TB sequelae for the health benefits of prompt TB diagnosis in high HIV prevalence settings: a mathematical modeling analysis

Background

Untreated pulmonary tuberculosis (TB) causes ongoing lung damage, which may persist after treatment. Conventional approaches for assessing TB health effects may not fully capture these mechanisms. We evaluated how TB-associated lung damage and post-TB sequalae affect the lifetime health consequences of TB in high HIV prevalence settings.

Methods

We developed a microsimulation model representing dynamic changes in lung function for individuals evaluated for TB in routine clinical settings. We parameterized the model with data for Uganda, Kenya, and South Africa, and estimated lifetime health outcomes under prompt, delayed, and no TB treatment scenarios. We compared results to earlier modelling approaches that omit progressive lung damage and post-TB sequelae.

Findings

We estimated 4.6 (95% uncertainty interval 3.4-5.8), 7.2 (5.1-9.6), and 18.0 (15.1-20.0) year reductions in life expectancy due to TB under prompt, delayed, and no treatment scenarios, respectively. Disability-adjusted life years (DALYs) from TB were estimated as 8.3 (6.2-10.6), 12.6 (9.0-17.0), and 27.8 (24.1-30.6) under prompt, delayed, and no treatment scenarios, respectively. Post-TB DALYs represented 9-53% of total DALYs. Modelling approaches that omit progressive lung damage and post-TB sequelae underestimated lifetime health losses of TB by 48-57%, and underestimated the benefits of prompt treatment by 45-64%.

Interpretation

Delayed initiation of TB treatment causes greater lung damage and higher mortality risks during and after the disease episode. In settings with co-prevalent TB and HIV, accounting for these factors substantially increased estimates of the lifetime disease burden and life expectancy loss caused by TB.

Funding

NIH.

Tuberculosis to lung cancer: application of tuberculosis signatures in identification of lung adenocarcinoma subtypes and marker screening

Background: There is an association between LUAD and TB, and TB increases the risk of lung adenocarcinogenesis. However, the role of TB in the development of lung adenocarcinoma has not been clarified. Methods: DEGs from TB and LUAD lung samples were obtained to identify TB-LUAD-shared DEGs. Consensus Clustering was performed on the TCGA cohort to characterize unique changes in TB transcriptome-derived lung adenocarcinoma subtypes. Prognostic models were constructed based on TB signatures to explore the characterization of subgroups. Finally, experimental validation and single-cell analysis of potential markers were performed. Results: We characterized three molecular subtypes with unique clinical features, cellular infiltration, and pathway change manifestations. We constructed and validated TB-related Signature in six cohorts. TB-related Signature has characteristic alterations, and can be used as an effective predictor of immunotherapy response. Prognostically relevant novel markers KRT80, C1QTNF6, and TRPA1 were validated by RT-qPCR. The association between KRT80 and lung adenocarcinoma disease progression was verified in Bulk transcriptome and single-cell transcriptome. Conclusion: For the first time, a comprehensive bioinformatics analysis of tuberculosis signatures was used to identify subtypes of lung adenocarcinoma. The TB-related Signature predicted prognosis and identified potential markers. This result reveals a potential pathogenic association of tuberculosis in the progression of lung adenocarcinoma.

Identification of 2-(N-aryl-1,2,3-triazol-4-yl) quinoline derivatives as antitubercular agents endowed with InhA inhibitory activity

The spread of drug-resistant tuberculosis strains has become a significant economic burden globally. To tackle this challenge, there is a need to develop new drugs that target specific mycobacterial enzymes. Among these enzymes, InhA, which is crucial for the survival of Mycobacterium tuberculosis, is a key target for drug development. Herein, 24 compounds were synthesized by merging 4-carboxyquinoline with triazole motifs. These molecules were then tested for their effectiveness against different strains of tuberculosis, including M. bovis BCG, M. tuberculosis, and M. abscessus. Additionally, their ability to inhibit the InhA enzyme was also evaluated. Several molecules showed potential as inhibitors of M. tuberculosis. Compound 5n displayed the highest efficacy with a MIC value of 12.5 μg/mL. Compounds 5g, 5i, and 5n exhibited inhibitory effects on InhA. Notably, 5n showed significant activity compared to the reference drug Isoniazid. Molecular docking analysis revealed interactions between these molecules and their target enzyme. Additionally, the molecular dynamic simulations confirmed the stability of the complexes formed by quinoline-triazole conjugate 5n with the InhA. Finally, 5n underwent in silico analysis to predict its ADME characteristics. These findings provide promising insights for developing novel small compounds that are safe and effective for the global fight against tuberculosis.

Application of metagenomic next-generation sequencing and targeted metagenomic next-generation sequencing in diagnosing pulmonary infections in immunocompetent and immunocompromised patients

Background

Metagenomic next-generation sequencing (mNGS) technology has been widely used to diagnose various infections. Based on the most common pathogen profiles, targeted mNGS (tNGS) using multiplex PCR has been developed to detect pathogens with predesigned primers in the panel, significantly improving sensitivity and reducing economic burden on patients. However, there are few studies on summarizing pathogen profiles of pulmonary infections in immunocompetent and immunocompromised patients in Jilin Province of China on large scale.

Methods

From January 2021 to December 2023, bronchoalveolar lavage fluid (BALF) or sputum samples from 546 immunocompetent and immunocompromised patients with suspected community-acquired pneumonia were collected. Pathogen profiles in those patients on whom mNGS was performed were summarized. Additionally, we also evaluated the performance of tNGS in diagnosing pulmonary infections.

Results

Combined with results of mNGS and culture, we found that the most common bacterial pathogens were Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii in both immunocompromised and immunocompetent patients with high detection rates of Staphylococcus aureus and Enterococcus faecium, respectively. For fungal pathogens, Pneumocystis jirovecii was commonly detected in patients, while fungal infections in immunocompetent patients were mainly caused by Candida albicans. Most of viral infections in patients were caused by Human betaherpesvirus 5 and Human gammaherpesvirus 4. It is worth noting that, compared with immunocompetent patients (34.9%, 76/218), more mixed infections were found in immunocompromised patients (37.8%, 14/37). Additionally, taking final comprehensive clinical diagnoses as reference standard, total coincidence rate of BALF tNGS (81.4%, 48/59) was much higher than that of BALF mNGS (40.0%, 112/280).

Conclusions

Our findings supplemented and classified the pathogen profiles of pulmonary infections in immunocompetent and immunocompromised patients in Jilin Province of China. Most importantly, our findings can accelerate the development and design of tNGS specifically used for regional pulmonary infections.

Tuberculosis Is Associated with Chronic Hypoxemia among Kenyan Adults (CHAKA): A Case-Control Study

Rationale: Data on risk factors for chronic hypoxemia in low- and middle-income countries are lacking. Objectives: We aimed to quantify the association between potential risk factors and chronic hypoxemia among adults hospitalized in Kenya. Methods: A hospital-based, case-control study was conducted at Moi Teaching and Referral Hospital in Eldoret, Kenya. Adult inpatients were screened on admission and enrolled in a 1:2 case-to-control ratio. Cases were patients with chronic hypoxemia, defined as resting oxygen saturation as measured by pulse oximetry (SpO2) ⩽ 88% on admission and either 1-month postdischarge SpO2 ⩽ 88% or, if they died before follow-up, documented SpO2 ⩽ 88% in the 6 months before enrollment. Control subjects were randomly selected, stratified by sex, among nonhypoxemic inpatients. Data were collected using questionnaires and structured chart review. Regression was used to assess the associations between chronic hypoxemia and age, sex, smoking status, biomass fuel use, elevation, and self-reported history of tuberculosis and human immunodeficiency virus diagnosis. Odds ratios (ORs) and 95% confidence intervals (CIs) are reported. Results: We enrolled 108 chronically hypoxemic cases and 240 nonhypoxemic control subjects into our Chronic Hypoxemia among Kenyan Adults (CHAKA) cohort. In multivariable analysis, compared with control subjects, chronically hypoxemic cases had significantly higher odds of older age (OR, 1.2 per 5-year increase [95% CI, 1.1-1.3]), female sex (OR, 3.6 [95% CI, 1.8-7.2]), current or former tobacco use (OR, 4.7 [95% CI, 2.3-9.6]), and prior tuberculosis (OR, 11.8 [95% CI, 4.7-29.6]) but no increase in the odds of human immunodeficiency virus diagnosis and biomass fuel use. Conclusions: These findings highlight the potential impact of prior tuberculosis on chronic lung disease in Kenya and the need for further studies on posttuberculosis lung disease.

Deep Learning Radiomics Analysis of CT Imaging for Differentiating Between Crohn's Disease and Intestinal Tuberculosis

This study aimed to develop and evaluate a CT-based deep learning radiomics model for differentiating between Crohn's disease (CD) and intestinal tuberculosis (ITB). A total of 330 patients with pathologically confirmed as CD or ITB from the First Affiliated Hospital of Zhengzhou University were divided into the validation dataset one (CD: 167; ITB: 57) and validation dataset two (CD: 78; ITB: 28). Based on the validation dataset one, the synthetic minority oversampling technique (SMOTE) was adopted to create balanced dataset as training data for feature selection and model construction. The handcrafted and deep learning (DL) radiomics features were extracted from the arterial and venous phases images, respectively. The interobserver consistency analysis, Spearman's correlation, univariate analysis, and the least absolute shrinkage and selection operator (LASSO) regression were used to select features. Based on extracted multi-phase radiomics features, six logistic regression models were finally constructed. The diagnostic performances of different models were compared using ROC analysis and Delong test. The arterial-venous combined deep learning radiomics model for differentiating between CD and ITB showed a high prediction quality with AUCs of 0.885, 0.877, and 0.800 in SMOTE dataset, validation dataset one, and validation dataset two, respectively. Moreover, the deep learning radiomics model outperformed the handcrafted radiomics model in same phase images. In validation dataset one, the Delong test results indicated that there was a significant difference in the AUC of the arterial models (p = 0.037), while not in venous and arterial-venous combined models (p = 0.398 and p = 0.265) as comparing deep learning radiomics models and handcrafted radiomics models. In our study, the arterial-venous combined model based on deep learning radiomics analysis exhibited good performance in differentiating between CD and ITB.

Exploitation of multiple host-derived nutrients by the yellow catfish epidermal environment facilitates Vibrio mimicus to sustain infection potency and susceptibility

Infection with Vibrio mimicus in the Siluriformes has demonstrated a rapid and high infectivity and mortality rate, distinct from other hosts. Our earlier investigations identified necrosis, an inflammatory storm, and tissue remodeling as crucial pathological responses in yellow catfish (Pelteobagrus fulvidraco) infected with V. mimicus. The objective of this study was to further elucidate the impact linking these pathological responses within the host during V. mimicus infection. Employing metabolomics and transcriptomics, we uncovered infection-induced dense vacuolization of perimysium; Several genes related to nucleosidase and peptidase activities were significantly upregulated in the skin and muscles of infected fish. Concurrently, the translation processes of host cells were impaired. Further investigation revealed that V. mimicus completes its infection process by enhancing its metabolism, including the utilization of oligopeptides and nucleotides. The high susceptibility of yellow catfish to V. mimicus infection was associated with the composition of its body surface, which provided a microenvironment rich in various nucleotides such as dIMP, dAMP, deoxyguanosine, and ADP, in addition to several amino acids and peptides. Some of these metabolites significantly boost V. mimicus growth and motility, thus influencing its biological functions. Furthermore, we uncovered an elevated expression of gangliosides on the surface of yellow catfish, aiding V. mimicus adhesion and increasing its infection risk. Notably, we observed that the skin and muscles of yellow catfish were deficient in over 25 polyunsaturated fatty acids, such as Eicosapentaenoic acid, 12-oxo-ETE, and 13-Oxo-ODE. These substances play a role in anti-inflammatory mechanisms, possibly contributing to the immune dysregulation observed in yellow catfish. In summary, our study reveals a host immune deviation phenomenon that promotes bacterial colonization by increasing nutrient supply. It underscores the crucial factors rendering yellow catfish highly susceptible to V. mimicus, indicating that host nutritional sources not only enable the establishment and maintenance of infection within the host but also aid bacterial survival under immune pressure, ultimately completing its lifecycle.

Challenges in Managing Newly Diagnosed Granulomatosis With Polyangiitis and Concurrent Respiratory Infections: A Retrospective Case Series

INTRODUCTION

Granulomatosis with polyangiitis (GPA), formerly termed Wegener's granulomatosis, is an autoimmune disease marked by necrotizing granulomatous inflammation and vasculitis affecting small-sized vessels. It commonly impacts the renal and respiratory systems.

MATERIALS AND METHODS

This retrospective case series sampling conducted in a tertiary care hospital between May 2023 and April 2024 examined six newly diagnosed GPA patients who were proteinase 3 cytoplasmic-antinuclear cytoplasmic antibody (PR3 c-ANCA) positive and had concurrent respiratory infections. None of them had any prior immunosuppressive conditions. The age range was 18-47 years with a mean of 35.0 (standard deviation: 11.83). All the patients had pneumonia (N=6, 100%). Out of all, five had bacterial pneumonia (N=5, 83.3%) and one had tuberculous pneumonia (N=1, 16.7%). A high level of PR3 c-ANCA (>150 RU/mL) was noted in four patients (N=4, 66.7%). Common symptoms included dry cough (N=5, 83.3%), loss of weight and appetite (N=2, 33.3%), and fever (N=2, 33.3%). Three patients had otitis media and/or nasal polyposis (N=3, 50%). Two patients (N=2, 33.3%) with life-threatening organ dysfunction were given concurrent antibiotics and steroids; the antibiotics were later modified based on culture and sensitivity results. One of these patients received antituberculosis therapy as Mycobacterium tuberculosis (MTB) was detected after 27 days of incubation in mycobacterial growth indicator tube broth. The remaining four patients (N=4, 66.7%) received antibiotics initially for 5-7 days until clinical resolution of pneumonia. Ultimately, they all showed clinical and radiological resolution (N=6, 100%) within 3-6 months of treatment.

RESULTS

The patients exhibited constitutional symptoms such as fever and weight loss; lower airway disease symptoms including dry cough and hemoptysis; nasal and ear disease symptoms like epistaxis, ear pain, and ear discharge; and a renal disease symptom, hematuria. Computed tomography of the thorax revealed bilateral consolidations, most of which were cavitating. Bronchoalveolar lavage cultures grew Escherichia coli, Burkholderia cepacia, Pseudomonas aeruginosa, Klebsiella pneumoniae, and MTB, whereas pus swab cultures from otitis media grew Pseudomonas aeruginosa, Staphylococcus aureus, and coagulase-negative staphylococci.

DISCUSSION

This study highlights the therapeutic challenges of GPA complicated by concurrent infections. Patients exhibited typical GPA signs, confirmed by PR3 c-ANCA levels. Concurrent infections require cautious antibiotic treatment before starting immunosuppressive therapy, except in life-threatening organ dysfunction. A unique case presented with both tuberculosis and GPA. Tailored treatment regimens combining antibiotics and immunosuppressives, including corticosteroids, methotrexate, and rituximab, resulted in clinical and radiological improvement in all the patients within 3-6 months. The addition of co-trimoxazole reduced the incidence of non-severe GPA relapses.

CONCLUSION

Tailored treatment plans addressing both infectious and autoimmune aspects are essential for optimal care in GPA complicated by concurrent infections. This study highlights the need for a multidisciplinary approach involving pulmonologist, rheumatologist, microbiologist, and pathologist in the diagnosis and treatment of GPA, emphasizing the importance of individualized treatment plans tailored to the specific clinical scenario.

Neutrophil extracellular traps characterize caseating granulomas

Tuberculosis (TB) remains one of the top 10 causes of death worldwide and still poses a serious challenge to public health. Recent attention to neutrophils has uncovered unexplored areas demanding further investigation. Therefore, the aim of this study was to determine neutrophil activation and circulatory neutrophil extracellular trap (NET) formation in various types of TB. Sera from TB patients (n = 91) and healthy controls (NHD; n = 38) were analyzed for NE-DNA and MPO-DNA complexes, cell-free DNA (cfDNA), and protease activity (elastase). We show that these NET parameters were increased in TB sera. Importantly, NET formation and NE activity were elevated in TB patients with extensive tissue damage when compared to those with minor damage and in patients with relapse, compared to new cases. We discuss the importance of balancing NET formation to prevent tissue damage or even relapse and argue to analyze circulating NET parameters to monitor the risk of disease relapse. To investigate the tissues for NETs and to find the source of the circulating NET degradation products, we collected sections of granulomas in lung and lymph node biopsies. Samples from other diseases with granulomas, including sarcoidosis (SARC) and apical periodontitis (AP), served as controls. Whereas NET formation characterizes the caseating granulomas, both caseating and non-caseating granulomas harbor DNA with unusual conformation. As TB is associated with hypercoagulation and thromboembolism, we further imaged the pulmonary vessels of TB patients and detected vascular occlusions with neutrophil aggregates. This highlights the dual role of neutrophils in the pathology of TB.

Circular RNAs in tuberculosis and lung cancer

This review signifies the role of circular RNAs (circRNAs) in tuberculosis (TB) and lung cancer (LC), focusing on pathogenesis, diagnosis, and treatment. CircRNAs, a newly discovered type of non-coding RNA, have emerged as key regulators of gene expression and promising biomarkers in various bodily fluids due to their stability. The current review discusses circRNA biogenesis, highlighting their RNase-R resistance due to their loop forming structure, making them effective biomarkers. It details their roles in gene regulation, including splicing, transcription control, and miRNA interactions, and their impact on cellular processes and diseases. For LC, the review identifies circRNA dysregulation affecting cell growth, motility, and survival, and their potential as therapeutic targets and biomarkers. In TB, it addresses circRNAs' influence on host anti-TB immune responses, proposing their use as early diagnostic markers. The paper also explores the interplay between TB and LC, emphasizing circRNAs as dual biosignatures, and the necessity for differential diagnosis. It concludes that no single circRNA biomarker is universally applicable for both TB and LC. Ultimately, the review highlights the pivotal role of circRNAs in TB and LC, encouraging further research in biomarker identification and therapeutic development concomitant for both diseases.

Correlation between Gene polymorphism levels of serum matrix metalloproteinases with cavitary features and pulmonary fibrosis of the Patient tuberculosis multi-drug resistance using high-resolution computerized tomography of the Thorax

Matrix metalloproteinases (MMPs) are proteins that play a role in the inflammatory and remodeling processes caused by infections, including pulmonary tuberculosis (TB), especially multidrug resistance. This study aims to investigate the relationship between variations in MMP-1 and MMP-9 blood levels, cavity features such as number, diameter, and wall thickness, and the location of fibrosis in multidrug-resistant (MDR) and drug-sensitive (DS) tuberculosis patients. This study used a comparative cross-sectional study design. The subjects, who were outpatients at Abdoel Moelok Hospital, Lampung, Indonesia, had passed the ethical test. We divided the subjects into two groups: 34 in the MDR-TB group and 36 in the DS-TB group. An ELISA test determined the levels of MMP-1 and MMP-9, while the PCR-sequencing method determined the genotypes of MMP-1 and MMP-9. Additionally, we measured cavities and fibrosis using thoracic high-resolution computerized tomography (HRCT) imaging. In MDR-TB patients, there was a significant difference in the number of cavities larger than 6.6 mm in diameter, as well as cavity thickness, compared to DS-TB patients. The distribution of fibrosis in lung segments was also significantly different in MDR-TB compared to DS-TB. Although MMP-9 levels in the MDR-TB group were higher than in the DS-TB group, there was no statistically significant difference. Based on HRCT measurements, this study found a link between MDR-TB and DS-TB in terms of the number of cavities, the diameter of the cavities, the thickness of the cavity walls, and the location of fibrosis in the affected lung segments. There was no link between the MMP-1 (-1607G) and MMP-9 (C1562T) genotypes and the levels of MMP-1 and MMP-9 in the blood. The MMP-1 genotype in the two study groups was very different and was linked to twice as many cases of MDR-TB. In addition, there was a substantial difference in cavity wall thickness between the G/G MMP-1 1607 genotype and the T/T MMP-9 genotype in the two study groups.

Advances in understanding immune homeostasis in latent tuberculosis infection

Nearly one-fourth of the global population is infected by Mycobacterium tuberculosis (Mtb), and approximately 90%-95% remain asymptomatic as latent tuberculosis infection (LTBI), an estimated 5%-10% of those with latent infections will eventually progress to active tuberculosis (ATB). Although it is widely accepted that LTBI transitioning to ATB results from a disruption of host immune balance and a weakening of protective immune responses, the exact underlying immunological mechanisms that promote this conversion are not well characterized. Thus, it is difficult to accurately predict tuberculosis (TB) progression in advance, leaving the LTBI population as a significant threat to TB prevention and control. This article systematically explores three aspects related to the immunoregulatory mechanisms and translational research about LTBI: (1) the distinct immunocytological characteristics of LTBI and ATB, (2) LTBI diagnostic markers discovery related to host anti-TB immunity and metabolic pathways, and (3) vaccine development focus on LTBI. This article is categorized under: Infectious Diseases > Molecular and Cellular Physiology Infectious Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Genetics/Genomics/Epigenetics.

Inhibition of leukotriene-B4 signalling-mediated host response to tuberculosis is a potential mode of adjunctive host-directed therapy

Treatment of tuberculosis (TB) is faced with several challenges including the long treatment duration, drug toxicity and tissue pathology. Host-directed therapy provides promising avenues to find compounds for adjunctively assisting antimycobacterials in the TB treatment regimen, by promoting pathogen eradication or limiting tissue destruction. Eicosanoids are a class of lipid molecules that are potent mediators of inflammation and have been implicated in aspects of the host response against TB. Here, we have explored the blood transcriptome of pulmonary TB patients to understand the activity of leukotriene B4, a pro-inflammatory eicosanoid. Our study shows a significant upregulation in the leukotriene B4 signalling pathway in active TB patients, which is reversed with TB treatment. We have further utilized our in-house network analysis algorithm, ResponseNet, to identify potential downstream signal effectors of leukotriene B4 in TB patients including STAT1/2 and NADPH oxidase at a systemic as well as local level, followed by experimental validation of the same. Finally, we show the potential of inhibiting leukotriene B4 signalling as a mode of adjunctive host-directed therapy against TB. This study provides a new mode of TB treatment along with mechanistic insights which can be further explored in pre-clinical trials.

Host Cell Death and Modulation of Immune Response against Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB), a prevalent infectious disease affecting populations worldwide. A classic trait of TB pathology is the formation of granulomas, which wall off the pathogen, via the innate and adaptive immune systems. Some key players involved include tumor necrosis factor-alpha (TNF-α), foamy macrophages, type I interferons (IFNs), and reactive oxygen species, which may also show overlap with cell death pathways. Additionally, host cell death is a primary method for combating and controlling Mtb within the body, a process which is influenced by both host and bacterial factors. These cell death modalities have distinct molecular mechanisms and pathways. Programmed cell death (PCD), encompassing apoptosis and autophagy, typically confers a protective response against Mtb by containing the bacteria within dead macrophages, facilitating their phagocytosis by uninfected or neighboring cells, whereas necrotic cell death benefits the pathogen, leading to the release of bacteria extracellularly. Apoptosis is triggered via intrinsic and extrinsic caspase-dependent pathways as well as caspase-independent pathways. Necrosis is induced via various pathways, including necroptosis, pyroptosis, and ferroptosis. Given the pivotal role of host cell death pathways in host defense against Mtb, therapeutic agents targeting cell death signaling have been investigated for TB treatment. This review provides an overview of the diverse mechanisms underlying Mtb-induced host cell death, examining their implications for host immunity. Furthermore, it discusses the potential of targeting host cell death pathways as therapeutic and preventive strategies against Mtb infection.

A mouse model of TB-associated lung fibrosis reveals persistent inflammatory macrophage populations during treatment

Post-TB lung disease (PTLD) causes a significant burden of global disease. Fibrosis is a central component of many clinical features of PTLD. To date, we have a limited understanding of the mechanisms of TB-associated fibrosis and how these mechanisms are similar to or dissimilar from other fibrotic lung pathologies. We have adapted a mouse model of TB infection to facilitate the mechanistic study of TB-associated lung fibrosis. We find that the morphologies of fibrosis that develop in the mouse model are similar to the morphologies of fibrosis observed in human tissue samples. Using Second Harmonic Generation (SHG) microscopy, we are able to quantify a major component of fibrosis, fibrillar collagen, over time and with treatment. Inflammatory macrophage subpopulations persist during treatment; matrix remodeling enzymes and inflammatory gene signatures remain elevated. Our mouse model suggests that there is a therapeutic window during which adjunctive therapies could change matrix remodeling or inflammatory drivers of tissue pathology to improve functional outcomes after treatment for TB infection.

Economic burden of chronic obstructive pulmonary disease and post-tuberculosis sequelae in low- and middle-income countries: a database compiled from a systematic review and meta-analysis

Background

Chronic obstructive pulmonary disease (COPD) and tuberculosis (TB) impose a substantial economic burden globally. This systematic review summarised the evidence on the costs of COPD, including post-TB diseases in low- and middle-income countries.

Methods

A systematic review was conducted and studies published between 1 January 2013 and 28 March 2022 (the date of the search) were identified using various electronic databases without language restrictions. Titles, abstracts and full texts were screened in duplicate and data were extracted and verified by reviewers. Eligible studies were categorised as cost analysis and/or economic burden studies, and costs were converted to 2021 United State dollar. Meta-analysis was conducted on the costs of hospitalisations, medication and outpatient visits.

Results

128 cost studies and 65 economic burden studies were included in this review. The data collected are presented in the Cost Database of COPD and Post-TB (CD-CPTB). The majority of studies were from Asia, Eastern Europe and Latin America, with a few from other middle-income countries. There were extremely limited data on the costs of post-TB sequelae and only a few studies were from Africa (n=6) and low-income (n=5) countries. The direct medical costs of COPD ranged from $26 per hospitalisation in India to $2694 per year per patient with severe disease in Mexico, while the costs of acute exacerbation of COPD ranged from $137 to $4207 per exacerbation with both the minimum and maximum costs occurring in Turkey. The costs were lower in lower middle-income countries compared with upper middle-income countries. Finally, considerable economic burden was attributable to smoking and air pollution.

Conclusion

The review and the CD-CPTB database give a thorough snapshot of the current evidence of the costs and economic burden of COPD and post-TB diseases. Future research is needed to investigate the economic impact after TB treatment and should be prioritised in Africa and low-income countries where there has been a lack of data collection.

Protocol registration number

CRD42022326609.