Biology subjects

Gusovsky, F.

Publications and source records attributed to Gusovsky, F..

3 recordsLinked to original sources

bioRxiv2023

The impact of vaccine-linked chemotherapy on liver health in a mouse model of chronic Trypanosoma cruzi infection

BackgroundChagas disease, chronic infection with Trypanosoma cruzi, mainly manifests as cardiac disease. However, the liver is important for both controlling parasite burdens and metabolizing drugs. Notably, high doses of anti-parasitic drug benznidazole (BNZ) causes liver damage. We previously showed that combining low dose BNZ with a prototype therapeutic vaccine is a dose sparing strategy that effectively reduced T. cruzi induced cardiac damage. However, the impact of this treatment on liver health is unknown. Therefore, we evaluated several markers of liver health after treatment with low dose BNZ plus the vaccine therapy in comparison to a curative dose of BNZ. MethodologyFemale BALB/c mice were infected with a bioluminescent T. cruzi H1 clone for approximately 70 days, then randomly divided into groups of 15 mice each. Mice were treated with a 25mg/kg BNZ, 25{micro}g Tc24-C4 protein/ 5{micro}g E6020-SE (Vaccine), 25mg/kg BNZ followed by vaccine, or 100mg/kg BNZ (curative dose). At study endpoints we evaluated hepatomegaly, parasite burden by quantitative PCR, cellular infiltration by histology, and expression of B-cell translocation gene 2(BTG2) and Peroxisome proliferator-activated receptor alpha (PPAR) by RT-PCR. Levels of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were quantified from serum. ResultsCurative BNZ treatment significantly reduced hepatomegaly, liver parasite burdens, and the quantity of cellular infiltrate, but significantly elevated serum levels of ALT, AST, and LDH. Low BNZ plus vaccine did not significantly affect hepatomegaly, parasite burdens or the quantity of cellular infiltrate, but only elevated ALT and AST. Low dose BNZ significantly decreased expression of both BTG2 and PPAR, and curative BNZ reduced expression of BTG2 while low BNZ plus vaccine had no impact. ConclusionsThese data confirm toxicity associated with curative doses of BNZ and suggest that the dose sparing low BNZ plus vaccine treatment better preserves liver health. Author SummaryChagas disease is a neglected tropical disease caused by the protozoal parasite Trypanosoma cruzi, which has long-term deleterious health effects. The current treatment for Chagas disease is administering the antiparasitic drug, benznidazole. While benznidazole effectively treats the disease during the acute phase, its efficacy is reduced during chronic infection. In addition, benznidazole therapy causes significant side effects, including liver toxicity. Texas Childrens Hospital Center for Vaccine Development at Baylor College of Medicine has developed a treatment strategy that combines a prototype therapeutic vaccine with a lower dose of Benznidazole to promote a protective immune response, ameliorate the deleterious effects of the parasite, and limit the harmful side effect of the drug. We call this vaccine-linked chemotherapy, which has shown promising results regarding heart health by reducing parasite burden and pathology in the heart and improving cardiac function. This study evaluated the strategys effectiveness in the liver since it is the prime metabolizer of the benznidazole drug, as well as the organ of parasite clearance. Results from this study demonstrated that vaccine-linked chemotherapy causes less damage to the liver compared to curative doses of benznidazole and may be a desirable treatment strategy to preserve overall health while retaining efficacy.

pathology↗

bioRxiv2023

A dirofilariasis mouse model for heartworm preclinical research

Use of experimental cats and dogs in veterinary heartworm preclinical drug research is increasing. As a potential alternative primary in vivo heartworm preventative drug screen, we assessed lymphopenic mice with ablation of the interleukin-2/7 common gamma chain ({gamma}c) as susceptible to the larval development phase of D. immitis. Non-obese diabetic (NOD) Severe Combined ImmunoDeficient (SCID){gamma}c-/-(NSG / NXG) mice consistently yielded viable D. immitis larvae at 2-4 weeks post-infection across multiple experiments, different batches of infectious larvae inoculates, different isolates of D. immitis and at independent laboratories. Mice did not display any overt clinical signs associated with infection up to 4 weeks. Developing larvae were found in subcutaneous and muscle fascia tissues, the natural site of this stage of heartworm in dogs. Larvae retrieved from NSG / NXG mice were mid-L4 stage of development. Compared with 14-day in vitro propagated larvae, in vivo derived L4 were significantly larger and contained expanded Wolbachia endobacteria titres, determined by QPCR and Fluorescent in situ Hybridisation (FISH). We established an ex vivo 6-day L4 paralytic screening system against nematodicidal agents (moxidectin, levamisole) which highlighted discrepancies in relative drug sensitivities in comparison with in vitro reared L4 D. immitis. We demonstrated effective depletion of Wolbachia by 70-90% in D. immitis L4 following 2-7 day oral in vivo exposures of NSG / NXG infected mice with doxycycline or the rapid-acting investigational anti-Wolbachia drug, AWZ1066S. We validated the NSG / NXG mouse model as a filaricide drug screen by in vivo treatments with single injections of moxidectin, which mediated 60-88% reduction in L4 larvae at 14-28 days. Future adoption of the mouse model as a first-line efficacy screen will benefit end-user laboratories conducting research and development of novel heartworm preventatives via increased access, rapid turnaround and reduced costs whilst simultaneously decreasing need for experimental cat or dog use.

microbiology↗

bioRxiv2022

Vaccine-linked chemotherapy with a low dose of benznidazole plus a bivalent recombinant protein vaccine prevents the development of cardiac fibrosis caused by Trypanosoma cruzi in BALB/c mice.

BackgroundChagas disease (CD) is caused by Trypanosoma cruzi and affects 6-7 million people worldwide. Approximately 30% of chronic patients develop chronic chagasic cardiomyopathy (CCC) after decades. Benznidazole (BNZ), one of the first-line chemotherapy approved for CD, induces toxicity and fails to halt the progression of CCC in chronic patients. The recombinant parasite-derived antigens, including Tc24, Tc24-C4, TSA-1, and TSA-1-C4 with Toll-like receptor 4 (TLR-4) agonist-adjuvants reduce cardiac parasite burdens, heart inflammation, and fibrosis, leading us to envision their use as immunotherapy together with BNZ. Given genetic immunization (DNA vaccines) encoding Tc24 and TSA-1 induce protective immunity in mice and dogs, we propose that immunization with the corresponding recombinant proteins offers an alternative and feasible strategy to develop these antigens as a bivalent human vaccine. We hypothesized that a low dose of BNZ in combination with a therapeutic vaccine (TSA-1-C4 and Tc24-C4 antigens formulated with a synthetic TLR-4 agonist-adjuvant, E6020-SE) could provide antigen-specific T cell immunity and prevent cardiac fibrosis progression. Methodology/ Principal findingsWe evaluated the therapeutic vaccine candidate plus BNZ (25 mg/kg/day/7 days) given at days 72 and 79 post-infection (p.i) (early chronic phase). Fibrosis, inflammation, and parasite burden were quantified in heart tissue at day 200 p.i. (late chronic phase). Further, spleen cells were collected to evaluate antigen-specific CD4+ and CD8+ T cell immune responses, using flow cytometry. We found that vaccine-linked BNZ treated mice had lower cardiac fibrosis compared to the infected untreated control group. Moreover, cells from mice that received the immunotherapy had higher stimulation index of antigen-specific CD8+Perforin+ T cells as well as antigen-specific central memory T cells compared to infected untreated control. ConclusionsOur results suggest that the bivalent immunotherapy together with BNZ treatment protects mice against cardiac fibrosis and activates strong CD8+ T cell responses by in vitro restimulation, evidencing the induction of a long-lasting T. cruzi-immunity. Author summaryChagas disease (CD) is a neglected tropical disease caused by the parasite Trypanosoma cruzi, transmitted through contact with infected feces of vectors bugs. CD can induce cardiac abnormalities including the development of fibrosis and eventually death. Benznidazole (BNZ) is the first-line drug approved against CD, however, its toxicity and lack of efficacy in the chronic phase have limited its use. Previous studies have demonstrated the feasibility of reducing doses of BNZ given in combination with therapeutic vaccines during the acute phase of CD, which increases its tolerability and reduces adverse side effects. Considering that patients are often diagnosed until prolonged stages of the disease, its necessary to evaluate therapies given in the chronic phase of CD. In this study, we evaluated a vaccine formulated with the recombinant T. cruzi-antigens TSA-1-C4 and Tc24-C4 and the adjuvant E6020-SE in combination with a low dose of BNZ given during the chronic phase of T. cruzi-infection using a murine model. The authors found that the combination therapy protects mice against cardiac fibrosis, allow the activation of a CD8+ T cell response and induce a prolonged memory response against T. cruzi. This study supports the development of the vaccine-linked chemotherapy approach in order to prevent T. cruzi chronic infection.

immunology↗