A novel thiocationic liposomal formulation of antisense oligonucleotides with activity against Mycobacterium tuberculosis

Versatility of Liposomes for Antisense Oligonucleotide Delivery: A Special Focus on Various Therapeutic Areas

Nucleic acid therapeutics, specifically antisense oligonucleotides (ASOs), can effectively modulate gene expression and protein function, leading to long-lasting curative effects. The hydrophilic nature and large size of oligonucleotides present translational challenges, which have led to the exploration of various chemical modifications and delivery systems. The present review provides insights into the potential role of liposomes as a drug delivery system for ASOs. The potential benefits of liposomes as an ASO carrier, along with their method of preparation, characterization, routes of administration, and stability aspects, have been thoroughly discussed. A novel perspective in terms of therapeutic applications of liposomal ASO delivery in several diseases such as cancer, respiratory disease, ophthalmic delivery, infectious diseases, gastrointestinal disease, neuronal disorders, hematological malignancies, myotonic dystrophy, and neuronal disorders remains the major highlights of this review.

Carbon nanomaterials: a new way against tuberculosis

Introduction: Tuberculosis (TB) remains one of the most alarming worldwide infectious diseases primarily in low-income countries, where the infection shows a higher and unvaried prevalence. In the last years, the emergence and spread of Mycobacterium tuberculosis (Mtb) strains resistant to first-line anti-TB drugs are the cause of major concern and prompted the implementation of new treatments, including the development of new drugs and the repurposing of old ones. Areas covered: In this review, we discuss solutions against TB based on nanomaterials (NMTs), alone or combined with current anti-TB drugs. We will summarize drug delivery platforms tested in in vivo or in vitro models and their activity against mycobacteria. We will describe how the new nanotechnologies based on carbon nanomaterials, like carbon nanotubes and graphene oxide are now facing the panorama of the medical fight against TB. Expert opinion: We foresee that in the next decade carbon nanomaterials will be at the forefront in fighting emerging antibiotic-resistant Mtb strains by shortening treatment periods, reducing adverse effects and mitigating antibiotic use. However, toxicity and biodegradation studies should be done prior to the clinical translation of carbon nanomaterials.

Quantification of Toxoplasma gondii in the tissues of BALB/c mice after immunization with nanoliposomal excretory-secretory antigens using Real-Time PCR

BACKGROUND

Toxoplasmosis is an infectious disease caused by the intracellular parasite Toxoplasma gondii. Although almost 1/3 of the world's population are seropositive, there is no effective vaccine against toxoplasmosis. Therefore, the development of an effective vaccine for control of toxoplasmosis is one of major concerns in parasitology. The aim of this study was to evaluate the efficacy of nano-liposomal excretory-secretory antigens (NLESA) in BALB/c mice.

MATERIALS AND METHODS

Excretory-secretory antigens (ESA) was obtained from tachyzoites, encapsulated in the liposome and studied by scanning electron microscope. BALB/c mice were immunized with NLESA and ESA, sterile phosphate-buffered saline (PBS). Immunization was performed three times at 14-day intervals and challenged with 1 × 10⁴ tachyzoites of T. gondii RH strain four weeks later. The parasite load of mice blood, brain and spleen tissues were determined using quantitative PCR targeted at the repeated element (RE) gene.

RESULTS

The immunization with NLESA and ESA induced a significant increase of anti-Toxoplasma IgG antibody compared with PBS group (P < 0.05). After challenge with tachyzoites, qPCR analyses showed significant reduction of parasite load in NLESA and ESA immunized mice compared with control group (P < 0.05). Also, NLESAs were more effective than ESAs and showed significantly reduced parasite load in blood (P = 0.001) and brain tissue (P = 0.01).

DISCUSSION

The vaccination with NLESA showed more promising results comparing to ESA. Further studies are recommended in order to achieve effectiveness of the vaccine against T. gondii.

Co-encapsulation of gallium with gentamicin in liposomes enhances antimicrobial activity of gentamicin against Pseudomonas aeruginosa

OBJECTIVES

The aim of this study was to enhance the antimicrobial efficacy of a liposomal gentamicin formulation with gallium metal (Lipo-Ga-GEN) against clinical isolates of Pseudomonas aeruginosa.

METHODS

Sputum isolates of P. aeruginosa from cystic fibrosis patients were used to determine the MIC and MBC of Lipo-Ga-GEN. P. aeruginosa biofilms were formed and used to compare the minimum biofilm eradication concentration of the conventional drugs with that of Lipo-Ga-GEN. Quorum sensing (QS) molecule reduction of P. aeruginosa was determined by monitoring N-acyl homoserine lactone production using Agrobacterium tumefaciens reporter strain (A136). Viability of the cultured human lung epithelial cells (A549) was determined by Trypan Blue assay in order to assess Ga toxicity.

RESULTS

MIC and MBC values indicated that gentamicin was more effective against a highly resistant strain of P. aeruginosa (PA-48913) when delivered as a Lipo-Ga-GEN formulation (256 mg/L free gentamicin versus 2 mg/L Lipo-Ga-GEN). Lipo-Ga-GEN was the only formulation that completely eradicated biofilms and blocked QS molecules at a very low concentration (0.94 mg/L gentamicin). The decrease in cell viability was less in A549 cells exposed to Lipo-Ga, suggesting that encapsulated Ga is safer.

CONCLUSIONS

The results clearly indicate that the Lipo-Ga-GEN formulation is more effective than gentamicin alone in eradicating antibiotic-resistant P. aeruginosa isolates growing in a planktonic or biofilm community.

Management of multidrug-resistant tuberculosis: Update 2007

Multidrug-resistant tuberculosis (MDR-TB) with bacillary resistance to at least isoniazid and rifampicin in vitro is a worldwide phenomenon. Hot spots of the disease are found scattered in different continents. Prevention of its development through good tuberculosis control programmes operating under the directly observed therapy, short-course (DOTS) strategy is of paramount importance. However, with established MDR-TB, treatment with alternative and specific chemotherapy is necessary to achieve a beneficial outcome. Such an approach on a programme basis is currently known as the 'DOTS-Plus' strategy. Second-line (reserve) drugs utilized in the treatment of MDR-TB are generally less potent and more toxic, perhaps with the notable exceptions of some fluoroquinolones and injectable agents. Surgery has a distinct adjunctive role for the management of MDR-TB in selected patients. The emergence of extensively drug-resistant tuberculosis (XDR-TB), that is, MDR-TB with additional bacillary resistance to the fluoroquinolones and injectables, has provided a very alarming challenge to global health, as the disease currently has a low cure rate and high mortality. In order to combat XDR-TB, strengthening of DOTS and DOTS-Plus programmes is mandatory, especially in the face of surging HIV infection. Furthermore, more attention needs to be focused on developing new drugs with potent bactericidal and sterilizing activities and low side-effects, and above all, drugs that are affordable for communities worldwide.