Effects of a food supplement rich in arginine in patients with smear positive pulmonary tuberculosis--a randomised trial

L-Tyrosine Limits Mycobacterial Survival in Tuberculous Granuloma

Caused by the intracellular pathogen Mycobacterium tuberculosis (Mtb), tuberculosis (TB) remains a massive global public health issue. A well-known and key TB trait is caseous necrotic granuloma, which allows mycobacteria to reactivate and disseminate, thus confounding TB eradication programs. Amino acid (AA) metabolism is key to regulating immune responses in Mtb infections; however, it is currently unclear if AAs can be used to treat tuberculous granulomas. Here, we screened 20 proteinogenic AAs using a Mycobacterium marinum-infected zebrafish granuloma model. Only L-tyrosine simultaneously reduced Mycobacterium marinum (M. marinum) levels in zebrafish larvae and adults and inhibited intracellular pathogen survival levels. Mechanistically, L-tyrosine significantly upregulated interferon-γ (IFN-γ) expression in M. marinum -infected zebrafish adults but not in larvae. Using N-acetylcysteine (NAC) to inhibit reactive oxygen species (ROS), L-tyrosine appeared to inhibit Mtb intracellular survival by promoting ROS production. Thus, L-tyrosine as a non-essential AA may reduce mycobacterial survival in both macrophages and tuberculous granulomas. Our research provides a platform for the clinical development of AAs for active or latent TB patients infected with drug-sensitive or drug-resistant Mtb.

Regulated Arginine Metabolism in Immunopathogenesis of a Wide Range of Diseases: Is There a Way to Pass between Scylla and Charybdis?

More than a century has passed since arginine was discovered, but the metabolism of the amino acid never ceases to amaze researchers. Being a conditionally essential amino acid, arginine performs many important homeostatic functions in the body; it is involved in the regulation of the cardiovascular system and regeneration processes. In recent years, more and more facts have been accumulating that demonstrate a close relationship between arginine metabolic pathways and immune responses. This opens new opportunities for the development of original ways to treat diseases associated with suppressed or increased activity of the immune system. In this review, we analyze the literature describing the role of arginine metabolism in the immunopathogenesis of a wide range of diseases, and discuss arginine-dependent processes as a possible target for therapeutic approaches.

Tuberculosis and malnutrition: The European perspective

Tuberculosis (TB) is a leading infectious cause of death worldwide, despite ongoing efforts to limit its incidence and mortality. Although the European Region has made gains in TB incidence and mortality, it now contends with increasing numbers of multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). Malnutrition is a major contributor to the burden of TB and may also be directly caused or enhanced by the onset of TB. The presence of malnutrition may worsen TB and MDR/RR-TB related treatment outcomes and contribute to growing TB drug-resistance. Preventing and treating all forms of malnutrition is an important tool to limit the spread of TB worldwide and improve TB outcomes and treatment efficacy. We carried out a scoping review of the existing evidence that addresses malnutrition in the context of TB. Our review found malnutrition increased the risk of developing TB in high-burden settings and increased the likelihood of developing unfavorable treatment outcomes, including treatment failure, loss to follow-up, and death. The potential impact of nutritional care and improved nutritional status on patient prognosis was more difficult to evaluate due to heterogeneity of patient populations, treatment protocols, and treatment durations and goals. High-quality trials that consider malnutrition as a major risk factor and relevant treatment target when designing effective strategies to limit TB spread and mortality are needed to inform evidence-based practice. In TB patients, we suggest that widespread and regular nutritional screening, assessment, and counselling, has the potential to increase effectiveness of TB management strategies and improve patient quality of life, overall outcomes, and survival.

IMPACT OF NUTRITIONAL CORRECTION OF PROTEIN METABOLISM DISORDERS ON THE CLINICAL COURSE OF PULMONARY TUBERCULOSIS

OBJECTIVE

The aim: To study the impact of nutritional correction of protein metabolism disorders on the clinical course of pulmonary tuberculosis.

PATIENTS AND METHODS

Materials and methods: The study involved 67 patients with pulmonary tuberculosis, which were divided into two groups: group I - 35 patients who underwent nutritional correction of protein metabolism disorders against the background of antimycobacterial therapy (AMBT) and group II - 32 patients who received standard AMBT. An assessment of clinical indicators and the condition of protein metabolism (PM) was conducted by determining the concentration of individual non-essential, essential amino acids and their total amount.

RESULTS

Results: The proposed correction scheme includes food products containing essential nutrients and biologically active compounds that have a positive impact on the corresponding links of pathogenesis and can be used throughout all phases of treatment. Its application had a positive impact on the indicators of PM (significant (p<0.05) increase in total amount of essential amino acids (TAEAA), total amount of non-essential amino acids (TANEAA) and total amount of amino acids (TAAA) in blood serum and the concentration of individual essential and non-essential amino acids (significantly reached the level of indicators in healthy individuals) and clinical course of tuberculosis (intoxication syndrome disappeared earlier by 10.8 ± 0.97 days, and respiratory one by 8.95 ± 1.68 days), there was an increase in the frequency of healing of decay cavities at the time of completion of treatment by 34.0% and a significant (p<0.05) reduction in the average duration of treatment by 21.1±2.91 days.

CONCLUSION

Conclusions: The application of nutritional correction of protein metabolism in the complex treatment of patients with pulmonary tuberculosis made it possible to obtain a pronounced positive impact on the clinical course of the disease and the condition of protein metabolism, which contributed to an increase in the effectiveness of treatment and rehabilitation.

Arginine-mediated gut microbiome remodeling promotes host pulmonary immune defense against nontuberculous mycobacterial infection

Nontuberculous mycobacterial pulmonary diseases (NTM-PDs) are emerging as global health threats with issues of antibiotic resistance. Accumulating evidence suggests that the gut-lung axis may provide novel candidates for host-directed therapeutics against various infectious diseases. However, little is known about the gut-lung axis in the context of host protective immunity to identify new therapeutics for NTM-PDs. This study was performed to identify gut microbes and metabolites capable of conferring pulmonary immunity to NTM-PDs. Using metabolomics analysis of sera from NTM-PD patients and mouse models, we showed that the levels of l-arginine were decreased in sera from NTM-PD patients and NTM-infected mice. Oral administration of l-arginine significantly enhanced pulmonary antimicrobial activities with the expansion of IFN-γ-producing effector T cells and a shift to microbicidal (M1) macrophages in the lungs of NTM-PD model mice. Mice that received fecal microbiota transplants from l-arginine-treated mice showed increased protective host defense in the lungs against NTM-PD, whereas l-arginine-induced pulmonary host defense was attenuated in mice treated with antibiotics. Using 16S rRNA sequencing, we further showed that l-arginine administration resulted in enrichment of the gut microbiota composition with Bifidobacterium species. Notably, oral treatment with either Bifidobacterium pseudolongum or inosine enhanced antimicrobial pulmonary immune defense against NTM infection, even with multidrug-resistant clinical NTM strains. Our findings indicate that l-arginine-induced gut microbiota remodeling with enrichment of B. pseudolongum boosts pulmonary immune defense against NTM infection by driving the protective gut-lung axis in vivo.

Mycobacterium tuberculosis SufR responds to nitric oxide via its 4Fe-4S cluster and regulates Fe-S cluster biogenesis for persistence in mice

The persistence of Mycobacterium tuberculosis (Mtb) is a major problem in managing tuberculosis (TB). Host-generated nitric oxide (NO) is perceived as one of the signals by Mtb to reprogram metabolism and respiration for persistence. However, the mechanisms involved in NO sensing and reorganizing Mtb's physiology are not fully understood. Since NO damages iron-sulfur (Fe-S) clusters of essential enzymes, the mechanism(s) involved in regulating Fe-S cluster biogenesis could help Mtb persist in host tissues. Here, we show that a transcription factor SufR (Rv1460) senses NO via its 4Fe-4S cluster and promotes persistence of Mtb by mobilizing the Fe-S cluster biogenesis system; suf operon (Rv1460-Rv1466). Analysis of anaerobically purified SufR by UV-visible spectroscopy, circular dichroism, and iron-sulfide estimation confirms the presence of a 4Fe-4S cluster. Atmospheric O₂ and H₂O₂ gradually degrade the 4Fe-4S cluster of SufR. Furthermore, electron paramagnetic resonance (EPR) analysis demonstrates that NO directly targets SufR 4Fe-4S cluster by forming a protein-bound dinitrosyl-iron-dithiol complex. DNase I footprinting, gel-shift, and in vitro transcription assays confirm that SufR directly regulates the expression of the suf operon in response to NO. Consistent with this, RNA-sequencing of MtbΔsufR demonstrates deregulation of the suf operon under NO stress. Strikingly, NO inflicted irreversible damage upon Fe-S clusters to exhaust respiratory and redox buffering capacity of MtbΔsufR. Lastly, MtbΔsufR failed to recover from a NO-induced non-growing state and displayed persistence defect inside immune-activated macrophages and murine lungs in a NO-dependent manner. Data suggest that SufR is a sensor of NO that supports persistence by reprogramming Fe-S cluster metabolism and bioenergetics.

Molecular Dynamics Studies of Therapeutic Liquid Mixtures and Their Binding to Mycobacteria

Tuberculosis is an highly contagious disease still considered by the WHO as one of most infectious diseases worldwide. The therapeutic approach, used to prevent and treat tuberculosis targets the Mycobacterium tuberculosis complex, comprises a combination of drugs administrated for long periods of time, which, in many cases, could cause several adverse effects and, consequently, low compliance of the patient to the treatment and drug-resistance. Therefore, therapeutic liquid mixtures formulated with anti-tuberculosis drugs and/or adjuvants in tuberculosis therapy are an interesting approach to prevent toxic effects and resistance to anti-tuberculosis drugs. The herein formulated therapeutic liquid mixtures, including ethambutol, arginine, citric acid and water under different molar ratios, were studied through a molecular dynamics approach to understand how ethambutol and arginine could be stabilized by the presence of citric acid and/or water in the mixture. To gain insights on how the uptake of these mixtures into the mycobacteria cell may occur and how a mycobacterial ABC transporter could contribute to this transport, multiple simultaneous ligand docking was performed. Interactions between citric acid and ethambutol involving the carboxyl and hydroxyl groups of citric acid with the amines of ethambutol were identified as the most critical ones. Water molecules present in the mixture provides the necessary network of hydrogen bonds that stabilize the mixture. Molecular docking additionally provided an interesting hypothesis on how the different mixture components may favor binding of ethambutol to an ABC importer. The data presented in this work helps to better understand these mixtures as well as to provide cues on the mechanisms that allow them to cross the mycobacterial cell membrane.

Metabolic Regulation of Immune Responses to Mycobacterium tuberculosis: A Spotlight on L-Arginine and L-Tryptophan Metabolism

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a leading cause of death worldwide. Despite decades of research, there is still much to be uncovered regarding the immune response to Mtb infection. Here, we summarize the current knowledge on anti-Mtb immunity, with a spotlight on immune cell amino acid metabolism. Specifically, we discuss L-arginine and L-tryptophan, focusing on their requirements, regulatory roles, and potential use as adjunctive therapy in TB patients. By continuing to uncover the immune cell contribution during Mtb infection and how amino acid utilization regulates their functions, it is anticipated that novel host-directed therapies may be developed and/or refined, helping to eradicate TB.

Host-directed therapy to combat mycobacterial infections

Upon infection, mycobacteria, such as Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM), are recognized by host innate immune cells, triggering a series of intracellular processes that promote mycobacterial killing. Mycobacteria, however, have developed multiple counter‐strategies to persist and survive inside host cells. By manipulating host effector mechanisms, including phagosome maturation, vacuolar escape, autophagy, antigen presentation, and metabolic pathways, pathogenic mycobacteria are able to establish long‐lasting infection. Counteracting these mycobacteria‐induced host modifying mechanisms can be accomplished by host‐directed therapeutic (HDT) strategies. HDTs offer several major advantages compared to conventional antibiotics: (a) HDTs can be effective against both drug‐resistant and drug‐susceptible bacteria, as well as potentially dormant mycobacteria; (b) HDTs are less likely to induce bacterial drug resistance; and (c) HDTs could synergize with, or shorten antibiotic treatment by targeting different pathways. In this review, we will explore host‐pathogen interactions that have been identified for Mtb for which potential HDTs impacting both innate and adaptive immunity are available, and outline those worthy of future research. We will also discuss possibilities to target NTM infection by HDT, although current knowledge regarding host‐pathogen interactions for NTM is limited compared to Mtb. Finally, we speculate that combinatorial HDT strategies can potentially synergize to achieve optimal mycobacterial host immune control.

Mycobacterium tuberculosis SufR Responds to Nitric oxide via its 4Fe-4S cluster and Regulates Fe-S cluster Biogenesis for Persistence in Mice.. [DOI: 10.1101/2020.08.10.245365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The persistence of Mycobacterium tuberculosis (Mtb) is a major problem in managing tuberculosis. Host–generated nitric oxide (NO) is perceived as one of the signals by Mtb to reprogram metabolism and respiration for persistence. However, the mechanisms involved in NO sensing and reorganizing Mtb′s physiology are not fully understood. Since NO damages iron–sulfur (Fe–S) clusters of essential enzymes, the mechanism(s) involved in regulating Fe–S cluster biogenesis could help Mtb persist in host tissues. Here, we show that a transcription factor SufR (Rv1460) senses NO via its 4Fe–4S cluster and promotes persistence of Mtb by mobilizing the Fe-S cluster biogenesis system; suf operon (Rv1460–Rv1466). Analysis of anaerobically purified SufR by UV-visible spectroscopy, circular dichroism, and iron-sulfide estimation confirms the presence of a 4Fe–4S cluster. Atmospheric O2 and H2O2 gradually degrade the 4Fe–4S cluster of SufR. Furthermore, electron paramagnetic resonance (EPR) analysis demonstrates that NO directly targets SufR 4Fe–4S cluster by forming a protein-bound dinitrosyl–iron–dithiol complex. DNase I footprinting, gel–shift, and in vitro transcription assays confirm that SufR directly regulates the expression of the suf operon in response to NO. Consistent with this, RNA–sequencing of Mtb ΔsufR demonstrates deregulation of the suf operon under NO stress. Strikingly, NO inflicted irreversible damage upon Fe–S clusters to exhaust respiratory and redox buffering capacity of MtbΔsufR. Lastly, Mtb ΔsufR failed to recover from a NO-induced non-growing state and displayed persistence defect inside immune–activated macrophages and murine lungs in a NO–dependent manner. Data suggest that SufR is a sensor of NO that supports persistence by reprogramming Fe–S cluster metabolism and bioenergetics.

Immunometabolism: new insights and lessons from antigen-directed cellular immune responses

Modulation of immune responses by nutrients is an important area of study in cellular biology and clinical sciences in the context of cancer therapies and anti-pathogen-directed immune responses in health and disease. We review metabolic pathways that influence immune cell function and cellular persistence in chronic infections. We also highlight the role of nutrients in altering the tissue microenvironment with lessons from the tumor microenvironment that shapes the quality and quantity of cellular immune responses. Multiple layers of biological networks, including the nature of nutritional supplements, the genetic background, previous exposures, and gut microbiota status have impact on cellular performance and immune competence against molecularly defined targets. We discuss how immune metabolism determines the differentiation pathway of antigen-specific immune cells and how these insights can be explored to devise better strategies to strengthen anti-pathogen-directed immune responses, while curbing unwanted, non-productive inflammation.

l-Arginine Synthesis from l-Citrulline in Myeloid Cells Drives Host Defense against Mycobacteria In Vivo

Immunonutrition as a therapeutic approach is rapidly gaining interest in the fight against infection. Targeting l-arginine metabolism is intriguing, considering this amino acid is the substrate for antimicrobial NO production by macrophages. The importance of l-arginine during infection is supported by the finding that inhibiting its synthesis from its precursor l-citrulline blunts host defense. During the first few weeks following pulmonary mycobacterial infection, we found a drastic increase in l-citrulline in the lung, even though serum concentrations were unaltered. This correlated with increased gene expression of the l-citrulline-generating (i.e., iNOS) and l-citrulline-using (i.e., Ass1) enzymes in key myeloid populations. Eliminating l-arginine synthesis from l-citrulline in myeloid cells via conditional deletion of either Ass1 or Asl resulted in increased Mycobacterium bovis bacillus Calmette-Guérin and Mycobacterium tuberculosis H₃₇R_v burden in the lungs compared with controls. Our data illustrate the necessity of l-citrulline metabolism for myeloid defense against mycobacterial infection and highlight the potential for host-directed therapy against mycobacterial disease targeting this nutrient and/or its metabolic pathway.

Properties of Therapeutic Deep Eutectic Solvents of l-Arginine and Ethambutol for Tuberculosis Treatment

The treatment for tuberculosis infection usually involves a prolonged regimen of multiple antibacterial drugs, which might lead to various secondary effects. For preventing drug resistance and side-effects of anti-tuberculosis drugs, new methods for improving the bioavailability of APIs were investigated. The strategy proposed consists of the preparation of therapeutic deep eutectic solvents (THEDES), that incorporate l-arginine and ethambutol. The eutectic mixtures were prepared by mixing the components at a certain molar ratio, until a clear liquid solution was formed. The prepared mixtures were characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and nuclear magnetic resonance spectroscopy (¹H and ¹³C-NMR). The solubility and permeability of the drugs when they are in the THEDES form was evaluated at 37 °C, in phosphate buffered saline (PBS). Solubility studies showed an increase of the solubility of ethambutol when incorporated in the eutectic system. The cytotoxicity was evaluated using a model cell line (Caco-2), comparing the cytotoxicity of the API incorporated in the eutectic system. We observed that the cell viability in the THEDES was affected by the presence of citric acid, and higher cytotoxicity values were observed. Nonetheless, these findings do not compromise the possibility to use these systems as new delivery systems for ethambutol and arginine.

BIOIMPEDANCE MARKERS AND TUBERCULOSIS OUTCOME AMONG HIV-INFECTED PATIENTS

Background

The changes in body composition markers (weight, fat mass, lean mass, and BMI) over time can be associated with TB treatment outcome among HIV-infected patients. The aim of this study was to investigate whether changes in fat mass and lean mass were associated with the treatment response among patients with HIV infection and pulmonary tuberculosis.

Materials and Methods

This was a prospective cohort study. Data from HIV-infected patients commencing TB therapy were analyzed. This included body weight measurement using bioimpedance equipment at baseline, one month, and two months after starting TB treatment.

Results

The study was conducted in 125 patients, 17 patients (13.6%) died during treatment, of which 5 died during the first month of treatment, 4 during the second month and 8 after the second month. The group of patients with good response, increased their weight by 1.3 kg (p <0.001) at the end of the first month of TB treatment and 2.6 kg in the second month (p <0.001), and body fat increase was 1.2 Kg (p <0.001) and 2.3 kg (p <0.001), the first and second month respectively. The group of patients who died had lost 2.1 kg fat mass after the first month (p <0.001) and 3.7 kg in the second month (p <0.001).

Conclusions

Our results show that the weight change during TB treatment (increased fat mass) helps us predict therapeutic response. Weight loss during the first month of starting therapy should be evaluated thoroughly to identify the probable cause of treatment failure.

Malnutrition: Modulator of Immune Responses in Tuberculosis

Nutrition plays a major role in the management of both acute and chronic diseases, in terms of body’s response to the pathogenic organism. An array of nutrients like macro- and micro-nutrients, vitamins, etc., are associated with boosting the host’s immune responses against intracellular pathogens including mycobacterium tuberculosis (M.tb). These nutrients have an immunomodulatory effects in controlling the infection and inflammation process and nutritional deficiency of any form, i.e., malnutrition may lead to nutritionally acquired immunodeficiency syndrome, which greatly increases an individual’s susceptibility to progression of infection to disease. This narrative review looks at the various mechanisms by which nutrition or its deficiency leads to impaired cell mediated and humoral immune responses, which in turn affects the ability of an individual to fight M.tb infection or disease. There is very little evidence in the literature that any specific food on its own or a specific quantity can alter the course of TB disease or be effective in the treatment of malnutrition. Further clinical trials or studies will be needed to recommend and to better understand the link between malnutrition, tuberculosis, and impaired immunity.

Adjuvant Efficacy of Nutrition Support During Pulmonary Tuberculosis Treating Course: Systematic Review and Meta-analysis

Background:

Malnutrition and tuberculosis (TB) tend to interact with each other. TB may lead to nutrition deficiencies that will conversely delay recovery by depressing immune functions. Nutrition support can promote recovery in the subject being treated for TB. The aim of this study was to evaluate the effectiveness of nutrition support on promoting the recovery of adult pulmonary TB patients with anti-TB drug therapy.

Methods:

English database of the Cochrane Controlled Trials Register, PubMed, EMBASE, and Chinese database of CBM, CNKI, VIP, and WANFANG were searched. Randomized controlled trials comparing nutrition support (given for more than 2 weeks) with no nutrition intervention, nutrition advice only, or placebo-control for TB patients being anti-TB treated were included. Two reviewers conducted data extraction, assessed the quality of the studies independently, and any discrepancies were solved by the third reviewer. Data were entered and analyzed by RevMan 5.2 software, and meta-analysis was done using risk ratios (RRs) for dichotomous variables and mean differences (MDs) for continuous variables with 95% confidence intervals (CIs).

Results:

A total of 19 studies (3681 participants) were included. In nutritional support for TB patients, pooled RR and its 95% CI of sputum smears- or culture-negative conversion rate and chest X-ray (CXR) absorption rate were 1.10 (1.04, 1.17) and 1.22 (1.08, 1.39), respectively, the pooled MD and its 95% CI of body mass index (BMI) and time of sputum smears or culture negativity were 0.59 (0.16, 1.2) and − 5.42 (−7.93, −2.92), respectively, compared with the control group. The differences in outcomes of CXR zone affected, TB score, serum albumin, and hemoglobin were not statistically significant (P = 0.76, 0.24, 0.28, and 0.20, respectively) between the intervention group and the control group. No systemic adverse events were recorded.

Conclusions:

During anti-TB course, nutrition support may be helpful in treatment of TB patients by improving both sputum smears- or culture-negative conversion rate and BMI, shortening the time of sputum conversion negative. Whether it can improve the final clinical effect, there still needs high-level quality studies to confirm in the future.

Using Survival Analysis to Identify Risk Factors for Treatment Interruption among New and Retreatment Tuberculosis Patients in Kenya

Despite high tuberculosis (TB) treatment success rate, treatment adherence is one of the major obstacles to tuberculosis control in Kenya. Our objective was to identify patient-related factors that were associated with time to TB treatment interruption and the geographic distribution of the risk of treatment interruption by county. Data of new and retreatment patients registered in TIBU, a Kenyan national case-based electronic data recording system, between 2013 and 2014 was obtained. Kaplan-Meier curves and log rank tests were used to assess the adherence patterns. Mixed-effects Cox proportional hazards modeling was used for multivariate analysis. Records from 90,170 patients were included in the study. The cumulative incidence of treatment interruption was 4.5% for new patients, and 8.5% for retreatment patients. The risk of treatment interruption was highest during the intensive phase of treatment. Having previously been lost to follow-up was the greatest independent risk factor for treatment interruption (HR: 4.79 [3.99, 5.75]), followed by being HIV-positive not on ART (HR: 1.96 [1.70, 2.26]) and TB relapse (HR: 1.70 [1.44, 2.00]). Male and underweight patients had high risks of treatment interruption (HR: 1.46 [1.35, 1.58]; 1.11 [1.03, 1.20], respectively). High rates of treatment interruption were observed in counties in the central part of Kenya while counties in the northeast had the lowest risk of treatment interruption. A better understanding of treatment interruption risk factors is necessary to improve adherence to treatment. Interventions should focus on patients during the intensive phase, patients who have previously been lost to follow-up, and promotion of integrated TB and HIV services among public and private facilities.

Nutritional supplements for people being treated for active tuberculosis

BACKGROUND

Tuberculosis and malnutrition are linked in a complex relationship. Tuberculosis may cause undernutrition through increased metabolic demands and decreased intake, and nutritional deficiencies may worsen the disease, or delay recovery by depressing important immune functions. At present, there is no evidence-based nutritional guidance for adults and children being treated for tuberculosis.

OBJECTIVES

To assess the effects of oral nutritional supplements in people being treated with antituberculous drug therapy for active tuberculosis.

SEARCH METHODS

We searched the Cochrane Infectious Disease Group Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL; Issue 1, 2016), MEDLINE (from 1946 to 4 February 2016), EMBASE (from 1980 to 4 February 2016), LILACS (from 1982 to 4 February 2016), the metaRegister of Controlled Trials (mRCT), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and the Indian Journal of Tuberculosis up to 4 February 2016, and checked the reference lists of all included studies.

SELECTION CRITERIA

Randomized controlled trials that compared any oral nutritional supplement given for at least four weeks with no nutritional intervention, placebo, or dietary advice only for people being treated for active tuberculosis. The primary outcomes of interest were all-cause death, and cure at six and 12 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and extracted data and assessed the risk of bias in the included trials. We presented the results as risk ratios (RR) for dichotomous variables, and mean differences (MD) for continuous variables, with 95% confidence intervals (CIs). Where appropriate, we pooled data from trials with similar interventions and outcomes. We assessed the quality of the evidence using the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Thirty-five trials, including 8283 participants, met the inclusion criteria of this review. Macronutrient supplementationSix trials assessed the provision of free food, or high-energy supplements. Only two trials measured total dietary intake, and in both trials the intervention increased calorie consumption compared to controls.The available trials were too small to reliably prove or exclude clinically important benefits on mortality (RR 0.34, 95% CI 0.10 to 1.20; four trials, 567 participants, very low quality evidence), cure (RR 0.91, 95% CI 0.59 to 1.41; one trial, 102 participants, very low quality evidence), or treatment completion (data not pooled; two trials, 365 participants, very low quality evidence).Supplementation probably produces a modest increase in weight gain during treatment for active tuberculosis, although this was not seen consistently across all trials (data not pooled; five trials, 883 participants, moderate quality evidence). Two small studies provide some evidence that quality of life may also be improved but the trials were too small to have much confidence in the result (data not pooled; two trials, 134 participants, low quality evidence). Micronutrient supplementationSix trials assessed multi-micronutrient supplementation in doses up to 10 times the dietary reference intake, and 18 trials assessed single or dual micronutrient supplementation.Routine multi-micronutrient supplementation may have little or no effect on mortality in HIV-negative people with tuberculosis (RR 0.86, 95% CI 0.46 to 1.6; four trials, 1219 participants, low quality evidence), or HIV-positive people who are not taking antiretroviral therapy (RR 0.92, 95% CI 0.69 to 1.23; three trials, 1429 participants, moderate quality evidence). There is insufficient evidence to know if supplementation improves cure (no trials), treatment completion (RR 0.99, 95% CI 0.95 to 1.04; one trial, 302 participants, very low quality evidence), or the proportion of people who remain sputum positive during the first eight weeks (RR 0.92, 95% CI 0.63 to 1.35; two trials, 1020 participants, very low quality evidence). However, supplementation may have little or no effect on weight gain during treatment (data not pooled; five trials, 2940 participants, low quality evidence), and no studies have assessed the effect on quality of life.Plasma levels of vitamin A appear to increase following initiation of tuberculosis treatment regardless of supplementation. In contrast, supplementation probably does improve plasma levels of zinc, vitamin D, vitamin E, and selenium, but this has not been shown to have clinically important benefits. Of note, despite multiple studies of vitamin D supplementation in different doses, statistically significant benefits on sputum conversion have not been demonstrated.

AUTHORS' CONCLUSIONS

There is currently insufficient research to know whether routinely providing free food, or energy supplements improves tuberculosis treatment outcomes, but it probably improves weight gain in some settings.Although blood levels of some vitamins may be low in people starting treatment for active tuberculosis, there is currently no reliable evidence that routinely supplementing above recommended daily amounts has clinical benefits.

One-stop TB-HIV services evaluation in Rwanda: comparison of the 2001-2005 and 2006-2010 cohorts

BACKGROUND

Tuberculosis (TB) and human immunodeficiency virus (HIV) co-infection remains high in Rwanda. Since one-stop TB-HIV services were implemented to manage TB-HIV co-infection, their functioning and impact on TB treatment outcomes have not been assessed.

OBJECTIVE

To evaluate one-stop TB-HIV services in Rwanda by comparing the TB treatment outcomes before and after their implementation in Kicukiro and Rulindo districts.

METHODS

This descriptive retrospective study used a quantitative questionnaire to determine the functioning of Rwanda's one-stop TB-HIV services. In-depth interviews and focus group discussions with health care providers, heads of facilities and co-infected patients were held to seek their opinion about the functioning of the services.

RESULTS

The one-stop TB-HIV services at all 12 health facilities visited were functioning according to the approved criteria. However, TB treatment outcomes after the intervention were not statistically different from those before the intervention. Qualitative data showed a positive impact on the quality of service, particularly a reduction in waiting times and appointments that were better respected as a result of the efficient functioning of the services.

CONCLUSION

One-stop TB-HIV services have improved the quality of service in Kicukiro and Rulindo districts. However, the services need to be strengthened programmatically to improve TB treatment outcomes.

A methodological evaluation and predictive in silico investigation into the multi-functionality of arginine in directly compressed tablets

The acceleration of solid dosage form product development can be facilitated by the inclusion of excipients that exhibit poly-/multi-functionality with reduction of the time invested in multiple excipient optimisations. Because active pharmaceutical ingredients (APIs) and tablet excipients present diverse densification behaviours upon compaction, the involvement of these different powders during compaction makes the compaction process very complicated. The aim of this study was to assess the macrometric characteristics and distribution of surface charges of two powders: indomethacin (IND) and arginine (ARG); and evaluate their impact on the densification properties of the two powders. Response surface modelling (RSM) was employed to predict the effect of two independent variables; Compression pressure (F) and ARG percentage (R) in binary mixtures on the properties of resultant tablets. The study looked at three responses namely; porosity (P), tensile strength (S) and disintegration time (T). Micrometric studies showed that IND had a higher charge density (net charge to mass ratio) when compared to ARG; nonetheless, ARG demonstrated good compaction properties with high plasticity (Y=28.01MPa). Therefore, ARG as filler to IND tablets was associated with better mechanical properties of the tablets (tablet tensile strength (σ) increased from 0.2±0.05N/mm(2) to 2.85±0.36N/mm(2) upon adding ARG at molar ratio of 8:1 to IND). Moreover, tablets' disintegration time was shortened to reach few seconds in some of the formulations. RSM revealed tablet porosity to be affected by both compression pressure and ARG ratio for IND/ARG physical mixtures (PMs). Conversely, the tensile strength (σ) and disintegration time (T) for the PMs were influenced by the compression pressure, ARG ratio and their interactive term (FR); and a strong correlation was observed between the experimental results and the predicted data for tablet porosity. This work provides clear evidence of the multi-functionality of ARG as filler, binder and disintegrant for directly compressed tablets.

Arginine adjunctive therapy in active tuberculosis

Background. Dietary supplementation has been used as a mechanism to augment the immune system. Adjunctive therapy with L-arginine has the potential to improve outcomes in active tuberculosis. Methods. In a randomized clinical trial 63 participants with smear-positive pulmonary tuberculosis in Markazi Province of Iran were given arginine or placebo for 4 weeks in addition to conventional chemotherapy. The final treatment success, sputum conversion, weight gain, and clinical symptoms after one and two months were considered as primary outcomes and secondary outcomes were ESR, CRP, and Hg. Data were collected and analyzed with SPSS software (ver. 18). Results. Arginine supplementation reduced constitutional symptoms (P = 0.032) in patients with smear-positive TB at the end of the first month of treatment. Arginine treated patients had significantly increased BMI at the end of the first and second months of treatment (P = 0.032 and P = 0.04) and a reduced CRP at the end of the first month of treatment (P = 0.03) versus placebo group. Conclusion. Arginine is useful as an adjunctive therapy in patients with active tuberculosis, in which the effects are more likely mediated by the increased production of nitric oxide and improved constitutional symptoms and weight gain. This trial is registered with Clinical Trials Registry of Iran: IRCT201211179855N2.

Nitrite produced by Mycobacterium tuberculosis in human macrophages in physiologic oxygen impacts bacterial ATP consumption and gene expression

In high enough concentrations, such as produced by inducible nitric oxide synthase (iNOS), reactive nitrogen species (RNS) can kill Mycobacterium tuberculosis (Mtb). Lesional macrophages in macaques and humans with tuberculosis express iNOS, and mice need iNOS to avoid succumbing rapidly to tuberculosis. However, Mtb's own ability to produce RNS is rarely considered, perhaps because nitrate reduction to nitrite is only prominent in axenic Mtb cultures at oxygen tensions ≤1%. Here we found that cultures of Mtb-infected human macrophages cultured at physiologic oxygen tensions produced copious nitrite. Surprisingly, the nitrite arose from the Mtb, not the macrophages. Mtb responded to nitrite by ceasing growth; elevating levels of ATP through reduced consumption; and altering the expression of 120 genes associated with adaptation to acid, hypoxia, nitric oxide, oxidative stress, and iron deprivation. The transcriptomic effect of endogenous nitrite was distinct from that of nitric oxide. Thus, whether or not Mtb is hypoxic, the host expresses iNOS, or hypoxia impairs the action of iNOS, Mtb in vivo is likely to encounter RNS by producing nitrite. Endogenous nitrite may slow Mtb's growth and prepare it to resist host stresses while the pathogen waits for immunopathology to promote its transmission.

L-arginine and vitamin D adjunctive therapies in pulmonary tuberculosis: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Vitamin D (vitD) and L-arginine have important antimycobacterial effects in humans. Adjunctive therapy with these agents has the potential to improve outcomes in active tuberculosis (TB).

METHODS

In a 4-arm randomised, double-blind, placebo-controlled factorial trial in adults with smear-positive pulmonary tuberculosis (PTB) in Timika, Indonesia, we tested the effect of oral adjunctive vitD 50,000 IU 4-weekly or matching placebo, and L-arginine 6.0 g daily or matching placebo, for 8 weeks, on proportions of participants with negative 4-week sputum culture, and on an 8-week clinical score (weight, FEV1, cough, sputum, haemoptysis). All participants with available endpoints were included in analyses according to the study arm to which they were originally assigned. Adults with new smear-positive PTB were eligible. The trial was registered at ClinicalTrials.gov NCT00677339.

RESULTS

200 participants were enrolled, less than the intended sample size: 50 received L-arginine + active vitD, 49 received L-arginine + placebo vit D, 51 received placebo L-arginine + active vitD and 50 received placebo L-arginine + placebo vitD. According to the factorial model, 99 people received arginine, 101 placebo arginine, 101 vitamin D, 99 placebo vitamin D. Results for the primary endpoints were available in 155 (4-week culture) and 167 (clinical score) participants. Sputum culture conversion was achieved by week 4 in 48/76 (63%) participants in the active L-arginine versus 48/79 (61%) in placebo L-arginine arms (risk difference -3%, 95% CI -19 to 13%), and in 44/75 (59%) in the active vitD versus 52/80 (65%) in the placebo vitD arms (risk difference 7%, 95% CI -9 to 22%). The mean clinical outcome score also did not differ between study arms. There were no effects of the interventions on adverse event rates including hypercalcaemia, or other secondary outcomes.

CONCLUSION

Neither vitD nor L-arginine supplementation, at the doses administered and with the power attained, affected TB outcomes.

REGISTRY

ClinicalTrials.gov. Registry number: NCT00677339.

Impaired pulmonary nitric oxide bioavailability in pulmonary tuberculosis: association with disease severity and delayed mycobacterial clearance with treatment

BACKGROUND

Nitric oxide (NO), a key macrophage antimycobacterial mediator that ameliorates immunopathology, is measurable in exhaled breath in individuals with pulmonary tuberculosis. We investigated relationships between fractional exhale NO (FENO) and initial pulmonary tuberculosis severity, change during treatment, and relationship with conversion of sputum culture to negative at 2 months.

METHODS

In Papua, we measured FENO in patients with pulmonary tuberculosis at baseline and serially over 6 months and once in healthy controls. Treatment outcomes were conversion of sputum culture results at 2 months and time to conversion of sputum microscopy results.

RESULTS

Among 200 patients with pulmonary tuberculosis and 88 controls, FENO was lower for patients with pulmonary tuberculosis at diagnosis (geometric mean FENO, 12.7 parts per billion [ppb]; 95% confidence interval [CI], 11.6-13.8) than for controls (geometric mean FENO, 16.6 ppb; 95% CI, 14.2-19.5; P = .002), fell further after treatment initiation (nadir at 1 week), and then recovered by 6 months (P = .03). Lower FENO was associated with more-severe tuberculosis disease, with FENO directly proportional to weight (P < .001) and forced vital-capacity (P = .001) and inversely proportional to radiological score (P = .03). People whose FENO increased or remained unchanged by 2 months were 2.7-fold more likely to achieve conversion of sputum culture than those whose FENO decreased (odds ratio, 2.72; 95% CI, 1.05-7.12; P = .04).

CONCLUSIONS

Among patients with pulmonary tuberculosis, impaired pulmonary NO bioavailability is associated with more-severe disease and delayed mycobacterial clearance. Measures to increase pulmonary NO warrant investigation as adjunctive tuberculosis treatments.

Shortening the 'short-course' therapy- insights into host immunity may contribute to new treatment strategies for tuberculosis

Achieving global control of tuberculosis (TB) is a great challenge considering the current increase in multidrug resistance and mortality rate. Considerable efforts are therefore being made to develop new effective vaccines, more effective and rapid diagnostic tools as well as new drugs. Shortening the duration of TB treatment with revised regimens and modes of delivery of existing drugs, as well as development of new antimicrobial agents and optimization of the host response with adjuvant immunotherapy could have a profound impact on TB cure rates. Recent data show that chronic worm infection and deficiencies in micronutrients such as vitamin D and arginine are potential areas of intervention to optimize host immunity. Nutritional supplementation to enhance nitric oxide production and vitamin D-mediated effector functions as well as the treatment of worm infection to reduce immunosuppressive effects of regulatory T (Treg) lymphocytes may be more suitable and accessible strategies for highly endemic areas than adjuvant cytokine therapy. In this review, we focus mainly on immune control of human TB, and discuss how current treatment strategies, including immunotherapy and nutritional supplementation, could be optimized to enhance the host response leading to more effective treatment.

Nutritional interventions for reducing morbidity and mortality in people with HIV

BACKGROUND

Adequate nutrition is important for optimal immune and metabolic function. Dietary support may, therefore, improve clinical outcomes in HIV-infected individuals by reducing the incidence of HIV-associated complications and attenuating progression of HIV disease, improving quality of life and ultimately reducing disease-related mortality.

OBJECTIVES

To evaluate the effectiveness of various macronutrient interventions, given orally, in reducing morbidity and mortality in adults and children living with HIV infection.

SEARCH METHODS

We searched CENTRAL (up to August 2011), MEDLINE (1966 to August 2011), EMBASE (1988 to August 2011), LILACS (up to February 2012), and Gateway (March 2006-February 2010). We also scanned reference lists of articles and contacted authors of relevant studies and other researchers.

SELECTION CRITERIA

Randomised controlled trials evaluating the effectiveness of macronutrient interventions compared with no nutritional supplements or placebo in the management of adults and children infected with HIV.

DATA COLLECTION AND ANALYSIS

Three reviewers independently applied study selection criteria, assessed study quality, and extracted data. Effects were assessed using mean difference and 95% confidence intervals. Homogenous studies were combined wherever it was clinically meaningful to do so and a meta-analysis using the random effects model was conducted.

MAIN RESULTS

Fourteen trials (including 1725 HIV positive adults and 271 HIV positive children), were included in this review. Neither supplementary food nor daily supplement of Spirulina significantly altered the risk of death compared with no supplement or placebo in malnourished, ART naive adult participants in the two studies which reported on this outcome. A nutritional supplement enhanced with protein did not significantly alter the risk of death compared to standard nutritional care in children with prolonged diarrhoea. Supplementation with macronutrient formulas given to provide protein and/or energy and fortified with micronutrients, in conjunction with nutrition counselling, significantly improved energy intake (3 trials; n=131; MD 393.57 kcal/day; 95% CI: 224.66 to 562.47;p<0.00001) and protein intake (2 trials; n=81; MD 23.5 g/day; 95% CI: 12.68, 34.01; p<0.00001) compared with no nutritional supplementation or nutrition counselling alone in adult participants with weight loss. In general supplementation with specific macronutrients such as amino acids, whey protein concentration or Spirulina did not significantly alter clinical, anthropometric or immunological outcomes compared with placebo in HIV-infected adults and children.

AUTHORS' CONCLUSIONS

Given the current evidence base, which is limited to fourteen relatively small trials all evaluating different macronutrient supplements in different populations at different stages of HIV infection and with varying treatment status, no firm conclusions can be drawn about the effects of macronutrient supplementation on morbidity and mortality in people living with HIV. It is, however, promising to see more studies being conducted in low-income countries, and particularly in children, where macronutrient supplementation both pre-antiretroviral treatment and in conjunction with antiretroviral treatment might prove to be beneficial.

Vitamin D enhances IL-1β secretion and restricts growth of Mycobacterium tuberculosis in macrophages from TB patients

The emergence of multidrug-resistant strains of Mycobacterium tuberculosis (MTB), the bacterium responsible for tuberculosis (TB), has rekindled the interest in the role of nutritional supplementation of micronutrients, such as vitamin D, as adjuvant treatment. Here, the growth of virulent MTB in macrophages obtained from the peripheral blood of patients with and without TB was studied. The H37Rv strain genetically modified to express Vibrio harveyi luciferase was used to determine the growth of MTB by luminometry in the human monocyte-derived macrophages (hMDMs) from study subjects. Determination of cytokine levels in culture supernatants was performed using a flow cytometry-based bead array technique. No differences in intracellular growth of MTB were observed between the different study groups. However, stimulation with 100nM 1,25-dihydroxyvitamin D significantly enhanced the capacity of hMDMs isolated from TB patients to control the infection. This effect was not observed in hMDMs from the other groups. The interleukin (IL)-1β and IL-10 release by hMDMs was clearly increased upon stimulation with 1,25-dihydroxyvitamin D. Furthermore, the 1,25-dihydroxyvitamin D stimulation also led to elevated levels of TNF-α (tumor necrosis factor-alpha) and IL-12p40. It was concluded that vitamin D triggers an inflammatory response in human macrophages with enhanced secretion of cytokines, as well as enhancing the capacity of hMDMs from patients with active TB to restrict mycobacterial growth.

Resistance to first-line anti-TB drugs is associated with reduced nitric oxide susceptibility in Mycobacterium tuberculosis

Background and Objective

The relative contribution of nitric oxide (NO) to the killing of Mycobacterium tuberculosis in human tuberculosis (TB) is controversial, although this has been firmly established in rodents. Studies have demonstrated that clinical strains of M. tuberculosis differ in susceptibility to NO, but how this correlates to drug susceptibility and clinical outcome is not known.

Methods

In this study, 50 sputum smear- and culture-positive patients with pulmonary TB in Gondar, Ethiopia were included. Clinical parameters were recorded and drug susceptibility profile and spoligotyping patterns were investigated. NO susceptibility was studied by exposing the strains to the NO donor DETA/NO.

Results

Clinical isolates of M. tuberculosis showed a dose- and time-dependent response when exposed to NO. The most frequent spoligotypes found were CAS1-Delhi and T3_ETH in a total of nine known spoligotypes and four orphan patterns. There was a significant association between reduced susceptibility to NO (>10% survival after exposure to 1 mM DETA/NO) and resistance against first-line anti-TB drugs, in particular isoniazid (INH). Patients infected with strains of M. tuberculosis with reduced susceptibility to NO showed no difference in cure rate or other clinical parameters but a tendency towards lower rate of weight gain after two months of treatment, independent of antibiotic resistance.

Conclusion:

There is a correlation between resistance to first-line anti-TB drugs and reduced NO susceptibility in clinical strains of M. tuberculosis. Further studies including the mechanisms of reduced NO susceptibility are warranted and could identify targets for new therapeutic interventions.

Immunity to TB and targets for immunotherapy

For centuries the treatment of TB has presented an enormous challenge to global health. In the 20th century, the treatment of TB patients with long-term multidrug therapy gave hope that TB could be controlled and cured; however, contrary to these expectations and coinciding with the emergence of AIDS, the world has witnessed a rampant increase in hard-to-treat cases of TB, along with the emergence of highly virulent and multidrug-resistant Mycobacterium tuberculosis strains. Unfortunately, these bacteria are now circulating around the world, and there are few effective drugs to treat them. As a result, the prospects for improved treatment and control of TB in the 21st century have worsened and we urgently need to identify new therapies that deal with this problem. The potential use of immunotherapy for TB is now of greater consideration than ever before, as immunotherapy could potentially overcome the problem of drug resistance. TB immunotherapy targets the already existing host anti-TB immune response and aims to enhance killing of the bacilli. For this purpose, several approaches have been used: the use of anti-Mycobacteria antibodies; enhancing the Th1 protective responses by using mycobacterial antigens or increasing Th1 cytokines; interfering with the inflammatory process and targeting of immunosuppressive pathways and targeting the cell activation/proliferation pathways. This article reviews our current understanding of TB immunity and targets for immunotherapy that could be used in combination with current TB chemotherapy.