title: Inhalable microparticles of nitric oxide donors induce phagosome maturation and kill Mycobacterium tuberculosis.
abstract: Nitric oxide (NO) kills Mycobacterium tuberculosis (Mtb) in vitro, but gaseous NO is difficult to administer to patients. We evaluated the consequences of intracellular delivery of NO using inhalable microparticles (MP) containing NO donors. MP containing 10% w/w of NO donors alone, or in addition to 25% each of isoniazid (INH) and rifabutin (RFB) in a polylactide-co-glycolide (PLGA) matrix were prepared by spray drying. THP-1-derived macrophages infected with Mtb H37Rv were exposed to MP or soluble NO donors. Phagosome-lysosome fusion (PLF) and bacterial killing were monitored. Colony forming units (cfu) in lungs and spleen of mice infected with a low-dose aerosol and administered inhalations of MP were enumerated. Bacterial DNA in these tissues was estimated by real-time PCR. In vitro studies indicated a bacteriostatic effect of NO donors despite significant enhancement of PLF. Daily inhalation of MP containing 10% diethylenetriamine nitric oxide adduct (DETA/NO) alone reduced log10 cfu in the lungs from 6.1 to 4.4 at the highest dose in four weeks, but did not significantly affect cfu in the spleen. Inhalations of MP containing DETA/NO in combination with INH and RFB significantly (P < 10(-5), ANOVA) reduced cfu in lungs and spleens by 4 log. Gross morphology and histology of the lungs and spleen indicated that inhaled particles were well-tolerated. Inhalable MP containing NO donors need further investigation as an adjunct to standard anti-tuberculosis chemotherapy.
authors.affiliation: Pharmaceutics Division, CSIR - Central Drug Research Institute, Chattar Manzil Palace, Lucknow 226001, India. rahul_niper@yahoo.com
authors.forename: Rahul Kumar
authors.initials: RK
authors.lastname: Verma
authors.forename: Atul Kumar
authors.initials: AK
authors.lastname: Agrawal
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Singh
authors.forename: Mradul
authors.initials: M
authors.lastname: Mohan
authors.forename: Anuradha
authors.initials: A
authors.lastname: Gupta
authors.forename: Pushpa
authors.initials: P
authors.lastname: Gupta
authors.forename: Umesh Datta
authors.initials: UD
authors.lastname: Gupta
authors.forename: Amit
authors.initials: A
authors.lastname: Misra
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D000995:Antitubercular Agents / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004359:Drug Therapy, Combination; D006801:Humans; D007538:Isoniazid / Q000627:therapeutic use; D008168:Lung / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D008297:Male; D051379:Mice; D008863:Microspheres; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D020030:Nitric Oxide Donors / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use; D010588:Phagosomes / Q000187:drug effects* / Q000502:physiology; D017828:Rifabutin / Q000627:therapeutic use; D013154:Spleen / Q000382:microbiology; D014376:Tuberculosis / Q000188:drug therapy* / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D020030:Nitric Oxide Donors; D017828:Rifabutin; D007538:Isoniazid