Browsing by Author "Sabi, Issa"

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N-acetylcysteine modulates markers of oxidation, inflammation and infection in tuberculosis
(Elsevier, 2025-01-03) Mapamba, Daniel; Sabi, Issa; Lalashowi, Julieth; Sauli, Elingarami; Buza, Joram; Olomi, Willyhelmina; Mtafya, Bariki; Kibona, Michael; Velen, Kavindhran; Hoelscher, Michael
Background Half the global tuberculosis health burden is due to post-tuberculosis lung disease. Host-directed therapies have been proposed to reduce this burden. N-acetylcysteine (NAC) provides the conditionally essential amino acid cysteine required for synthesis of glutathione, an antioxidant thiol. We recently reported clinical outcomes of a trial of adjunctive NAC in patients with pulmonary tuberculosis, finding that NAC improved the secondary endpoint of recovery of lung function. Here we report the effects of NAC on biomarkers of oxidation, inflammation, and infection in that trial. Methods 140 adults with moderate or far-advanced pulmonary tuberculosis were randomly assigned to standard tuberculosis treatment with or without NAC 1200 mg twice daily for months 1-4. Sputum and blood samples were obtained at specified intervals to measure total glutathione, MTB-induced cytokines, haemoglobin, whole blood mycobactericidal activity (WBA), and sputum MTB burden. Results NAC treatment rapidly increased total glutathione (P<.0001), but levels did not reach those of healthy volunteers (P<.001). NAC reduced MTB-induced TNF-α (P =.011) without affecting IL-10, and accelerated the recovery of hemoglobin in participants with low values on entry. NAC did not affect killing in ex vivo whole blood culture but did slow the clearance of MTB from sputum (P=0.003). Conclusion Adjunctive NAC showed antioxidant and anti-inflammatory effects consistent with the amelioration of immunopathology seen in preclinical models. Two biomarkers of antimicrobial activity showed discordant results; neither demonstrated the enhanced antimicrobial effects seen preclinically. The reduction of oxidative stress and inflammation by NAC may explain its effects on the recovery of lung function post-TB.
Performance of Tuberculosis Molecular Bacterial Load Assay Compared to Alere TB-LAM in Urine of Pulmonary Tuberculosis Patients with HIV Co-Infections
(MDPI, 2023-02-23) Mapamba, Daniel; Sauli, Elingarami; Lalashowi, Julieth; Buza, Joram; John, Joseph; Mwaisango, Zawadi; Tarmo, Peter; Sabi, Issa; Rachow, Andrea; Ntinginya, Nyanda; Mtafya, Bariki
Alternative tools are needed to improve the detection of M. tuberculosis (M. tb) in HIV co-infections. We evaluated the utility of Tuberculosis Molecular Bacterial Load Assay (TB-MBLA) compared to lipoarabinomannan (LAM) to detect M. tb in urine. Sputum Xpert MTB/RIF-positive patients were consented to provide urine at baseline, weeks 2, 8, 16, and 24 of treatment for TB-MBLA, culture, and LAM. Results were compared with sputum cultures and microscopy. Initial M. tb. H37Rv spiking experiments were performed to validate the tests. A total of 63 urine samples from 47 patients were analyzed. The median age (IQR) was 38 (30–41) years; 25 (53.2%) were male, 3 (6.5%) had urine for all visits, 45 (95.7%) were HIV positive, of whom 18 (40%) had CD4 cell counts below 200 cells/µL, and 33 (73.3%) were on ART at enrollment. Overall urine LAM positivity was 14.3% compared to 4.8% with TB-MBLA. Culture and microscopy of their sputum counterparts were positive in 20.6% and 12.7% of patients, respectively. Of the three patients with urine and sputum at baseline, one (33.33%) had urine TB-MBLA and LAM positive compared to 100% with sputum MGIT culture positive. Spearman’s rank correction coefficient (r) between TB-MBLA and MGIT was −0.85 and 0.89 with a solid culture, p > 0.05. TB-MBLA has the promising potential to improve M. tb detection in urine of HIV-co-infected patients and complement current TB diagnostics.