Immune responses of Leishmania donovani infected BALB/c mice following treatment with free and vesicular sodium stibogluconate formulations

Effect of sodium stibogluconate in recruiting and awakening immune cells in the pleural fluid of pancreatic cancer: preparation for immunotherapy

Ascites and pleural effusion are recognized complications of pancreatic cancer. These diseases are accompanied by ascites and pleural effusion, and drug treatment is limited by high costs, long hospital stays, and failure rates. Immunotherapy may offer new option, but in most patients with late stages of cancer, immune cells may lose the ability to recognize tumor cells, how to activate their immune cells is a major problem, sodium glucosidate (SSG) is injected into ascites as a protein tyrosine phosphatase inhibitor to wake up immune cells and prepare for immunotherapy. We used single-cell RNA sequencing (scRNA-seq) to investigate whether and how SSG injected into ascites of pancreatic cancer elicits an immune response. Our study showed that the process of SSG fusion treatment of ascites and pleural effusion, the interaction between TandNK cells, MPs cells, monocytes and neutrophils was induced, and large numbers of genes were expressed, resulting in upregulation of immune response, which also approved that SSG is not only used as a protein tyrosine phosphatase inhibitor, but also it works as a protein tyrosine phosphatase inhibitor. It can also be used to regulate immune cell function, recruiting immune cells to the right place with the help of PD-1 or PD-L1 to fight cancer cells in ascites and pleural effusions in cancer patients.

Nanoliposomal artemisinin for the treatment of murine visceral leishmaniasis

Visceral leishmaniasis (VL) is a fatal, vector-borne disease caused by the intracellular protozoa of the genus Leishmania. Most of the therapeutics for VL are toxic, expensive, or ineffective. Sesquiterpenes are a new class of drugs with proven antimicrobial and antiviral activities. Artemisinin is a sesquiterpene lactone with potent antileishmanial activity, but with limited access to infected cells, being a highly lipophilic molecule. Association of artemisinin with liposome is a desirable strategy to circumvent the problem of poor accessibility, thereby improving its efficacy, as demonstrated in a murine model of experimental VL. Nanoliposomal artemisinin (NLA) was prepared by thin-film hydration method and optimized using Box–Behnken design with a mean particle diameter of 83±16 nm, polydispersity index of 0.2±0.03, zeta potential of −27.4±5.7 mV, and drug loading of 33.2%±2.1%. Morphological study of these nanoliposomes by microscopy showed a smooth and spherical surface. The mechanism of release of artemisinin from the liposomes followed the Higuchi model in vitro. NLA was free from concomitant signs of toxicity, both ex vivo in murine macrophages and in vivo in healthy BALB/c mice. NLA significantly denigrated the intracellular infection of Leishmania donovani amastigotes and the number of infected macrophages ex vivo with an IC₅₀ of 6.0±1.4 µg/mL and 5.1±0.9 µg/mL, respectively. Following treatment in a murine model of VL, NLA demonstrated superior efficacy compared to artemisinin with a percentage inhibition of 82.4%±3.8% in the liver and 77.6%±5.5% in spleen at the highest dose of 20 mg/kg body weight with modulation of cell-mediated immunity towards protective Th1 type. This study is the first report on the use of a liposomal drug delivery system for artemisinin as a promising alternative intervention against VL.

Reduced Tissue Parasitic Load and Infectivity to Sand Flies in Dogs Naturally Infected by Leishmania ( Leishmania ) chagasi following Treatment with a Liposome Formulation of Meglumine Antimoniate

The toxicity and antileishmanial effectiveness of a novel liposome formulation of meglumine antimoniate in mongrel dogs with visceral leishmaniasis (VL) obtained from a region where VL is endemic in Brazil have been investigated. Groups of 12 animals received by the intravenous route four doses (with 4-day intervals) of either liposomal meglumine antimoniate (group I [GI], 6.5 mg Sb/kg of body weight/dose), empty liposomes (GII), or isotonic saline (GIII). Evaluation of markers of hematopoietic, hepatic, and renal functions before and just after treatment showed no significant change. On the other hand, transitory adverse reactions, including prostration, defecation, tachypnea, and sialorrhea, were observed during the first 15 min after injections in GI and GII. Parasitological evaluation of sternal bone marrow 4 days after the last dose showed a significant reduction of parasite burden in GI, compared to the other groups. Immunocytochemical evaluations of the skin, bone marrow, cervical lymph nodes, livers, and spleens of dogs for parasites, 150 days after treatment, indicated significant parasite suppression (higher than 95.7%) in the lymph nodes, livers, and spleens of GI, compared to control groups. Feeding of Lutzomyia longipalpis phlebotomines on dogs from GI, 150 days after treatment, resulted in a significant reduction of sand fly infection efficiency, compared to feeding on animals from GII and GIII. This is the first report of both long-term parasite suppression and reduction of infectivity to sand flies in naturally infected dogs following treatment with a liposome-encapsulated drug. Importantly, this was achieved using a 20-fold-lower cumulative dose of Sb than is used for conventional antimonial treatment.

Natural history and surgical treatment of brown tumor lesions at various sites in refractory primary hyperparathyroidism

OBJECTIVE

Nowadays, the occurrence of brown tumor lesions or osteitis fibrosa cystica caused by long-lasting primary hyperparathyroidism are very rare, since measuring serum calcium became available routinely in the mid-1970s. It is a tumor-like lesion that may affect the entire skeleton, often presenting with diffuse focal bone pain or by pathological fracture.

METHODS

We describe our experience of brown tumor lesions at different skeletal sites that were treated at our trauma centre within the last two years. This included surgical therapy for the indications (i) pain at the pelvis, (ii) increased risk for pathological fracture at the tibia and (iii) acute radicular symptoms at the lumbar spine. The literature was reviewed for the current understanding of the pathophysiology as well as therapy of brown tumor lesions in primary hyperparathyroidism.

RESULTS

Curettage of a left-sided iliac crest brown tumor terminated focal pain. A less invasive stabilisation system and bone cement decreased both patient pain and the fracture risk of brown tumor lesion sites of the shinbone; and internal fixator including laminectomy at the lumbar spine ended radicular symptoms.

CONCLUSION

Patients with refractory primary hyperparathyroidism should be monitored closely by endocrinologists and the patient's serum calcium level should be adjusted as far as possible. Radiography is required only if focal bone pain or pathological fractures or radicular symptoms occur. Surgery should be considered if large bone defects with spontaneous fracture risk or increasing pain are present. Tumor curettage, Palacos plombage and less invasive stabilisation systems have proved to be acceptable surgical options.

Sodium stibogluconate resistance in Leishmania donovani correlates with greater tolerance to macrophage antileishmanial responses and trivalent antimony therapy

Co-treatment of mice infected with different strains of Leishmania donovani with a non-ionic surfactant vesicle formulation of buthionine sulfoximine (BSO-NIV), and sodium stibogluconate (SSG), did not alter indicators of Th1 or Th2 responses but did result in a significant strain-independent up-regulation of IL6 and nitrite levels by stimulated splenocytes from treated mice compared to controls. The efficacy of BSO-NIV/SSG treatment was dependent on the host being able to mount a respiratory burst indicating that macrophages are important in controlling the outcome of treatment. In vitro studies showed that SSG resistance was associated with a greater resistance to killing by activated macrophages, treatment with hydrogen peroxide or potassium antimony tartrate. Longitudinal studies showed that a SSG resistant (SSG-R) strain was more virulent than a SSG susceptible (SSG-S) strain, resulting in significantly higher parasite burdens by 4 months post-infection. These results indicate that SSG exposure may favour the emergence of more virulent strains.

In vitro and in vivo activities of a triterpenoid saponin extract (PX-6518) from the plant Maesa balansae against visceral leishmania species

The in vitro and in vivo activities of a mixture of six oleane triterpene saponins, recovered from the methanolic extract of the leaves of the Vietnamese plant Maesa balansae (PX-6518), were evaluated against drug-sensitive visceral Leishmania strains. The in vitro 50% inhibitory concentration (IC(50)) against intracellular Leishmania infantum amastigotes was 0.04 micro g/ml. The cytotoxic concentrations causing 50% cell death (CC(50)s) were about 1 micro g/ml in murine macrophage host cells and >32 micro g/ml in human fibroblasts (MRC-5 cell line). Evaluation in the Leishmania donovani BALB/c mouse model indicated that a single subcutaneous administration of 0.4 mg/kg at 1 day after infection reduced liver amastigote burdens by about 95% in all treated animals. If treatment was delayed until 14 days after infection, a dose of 1.6 mg/kg of body weight was required to maintain the same level of activity. Single 250-mg/kg doses of sodium stibogluconate (Pentostam) 1 and 14 days after infection produced comparable efficacies. A single dose of PX-6518 at 2.5 mg/kg administered 5 days before infection was still 100% effective in preventing liver infection, suggesting a particularly long residual action. Spleen and bone marrow could not be cleared by PX-6518 nor sodium stibogluconate. PX-6518 did not show activity after oral dosing at up to 200 mg/kg for 5 days. This study concludes that triterpenoid saponins from M. balansae show promising in vitro and in vivo antileishmanial potential and can be considered as new lead structures in the search for novel antileishmanial drugs.

Pharmacokinetics, toxicities, and efficacies of sodium stibogluconate formulations after intravenous administration in animals

The pharmacokinetics and toxicities of free sodium stibogluconate (SSG) and two vesicular formulations of this drug (a nonionic surfactant vesicular formulation of SSG [SSG-NIV] and SSG-NIV-dextran) were determined after treatment with a single intravenous dose in healthy dogs and were related to their antileishmanial efficacies in mice. Analysis of the curves of the concentrations in plasma after intravenous administration of SSG and SSG-NIV in dogs showed that both formulations produced similar antimony (Sb) pharmacokinetics. In contrast, treatment with SSG-NIV-dextran significantly modified the pharmacokinetics of the drug. The elimination half-life was four times longer (280 min) than that observed after administration of SSG (71 min) (P = 0.01), and the volume of distribution at steady state (V(SS)) was also increased (V(SS) for SSG, 0.21 liters/kg; V(SS) for SSG-NIV-dextran, 0.34 liters/kg [P = 0.02]), thus indicating that drug encapsulation favors the distribution of Sb into organs and increases its residence time in tissues. This would explain the superior antileishmanial efficacy of this formulation compared to those of the free drug in mice. No signs of toxicity were found in dogs after SSG and SSG-NIV administration. However, SSG-NIV-dextran treatment was associated with short-term toxicity, demonstrated by the development of chills and diarrhea, which cleared by 24 h postdosing, and hepatic dysfunction at 24 h postdosing (P < 0.05). The levels of all the biochemical parameters had returned to normal at 1 month postdosing. No signs of toxicity were observed in mice treated with all three formulations.

The cured immune phenotype achieved by treatment of visceral leishmaniasis in the BALB/c mouse with a nonionic surfactant vesicular formulation of sodium stibogluconate does not protect against reinfection

Single-dose treatment with sodium stibogluconate solution (SSG) and treatment with a nonionic surfactant vesicular formulation of sodium stibogluconate (SSG-NIV) were compared for the ability to protect BALB/c mice against infection with Leishmania donovani. Prophylactic treatment with SSG-NIV protected against infection, although its effects were time and organ dependent; protection was not obtained with SSG. Protection against reinfection with L. donovani was observed only in mice cured by treatment with SSG-NIV. However, this protective effect was probably due to the presence of residual drug rather than an immune effect, since prophylactic SSG-NIV treatment gave similar results. Transfer of enriched spleen T-cell populations from L. donovani-infected mice or from infected SSG-NIV-treated mice gave no protection against L. donovani infection in the recipients. T cells from infected mice, but not from infected SSG-NIV-treated mice, were infectious to recipients. SSG-NIV treatment was equally effective against visceral leishmaniasis in immunocompetent and SCID mice, whereas SSG treatment was less effective in the latter. The results of this study suggest that the high antileishmanial activity of SSG-NIV is due to favorable modification of SSG delivery and does not require a fully functional immune response. Cure of visceral leishmaniasis by SSG-NIV treatment in the BALB/c mouse did not protect against reinfection.

Visceral leishmaniasis in the BALB/c mouse: a comparison of the efficacy of a nonionic surfactant formulation of sodium stibogluconate with those of three proprietary formulations of amphotericin B

In this study, treatment efficacies of a nonionic surfactant vesicle formulation of sodium stibogluconate (SSG-NIV) and of several formulations of amphotericin B were compared in a murine model of visceral leishmaniasis. Treatment with multiple doses of AmBisome, Abelcet, and Amphocil (total dose, 12.5 mg of amphotericin B/kg of body weight) resulted in a significant suppression of parasite burdens in liver (P < 0.0005) and spleen (P < 0.0005) compared with those of controls, with Abelcet having the lowest activity. Only AmBisome and Amphocil gave significant suppression of parasites in bone marrow (compared to control values, P < 0.005). In the acute-infection model, single-dose treatments of SSG-NIV (296 mg of SbV/kg), SSG solution (296 mg of SbV/kg), or AmBisome (8 mg of amphotericin B/kg) were equally effective against liver parasites (compared to control values, P < 0.0005). SSG-NIV and AmBisome treatment also significantly suppressed parasites in bone marrow and spleen (P < 0.005), with SSG-NIV treatment being more suppressive (>98% suppression in all three sites). Free-SSG treatment failed to suppress spleen or bone marrow parasites. Infection status influenced treatment outcome. In the chronic-infection model, the AmBisome single-dose treatment was less effective in all three infection sites and the SSG-NIV single-dose treatment was less effective in the spleen. The results of this study suggest that the antileishmanial efficacy of SSG-NIV compares favorably with those of the novel amphotericin B formulations.