In vitro evaluation of the suppressive effect of chitosan/poly(vinyl alcohol) microspheres on attachment of C. parvum to enterocytic cells

Assessment of chitosan nanoparticles in improving the efficacy of nitazoxanide on cryptosporidiosis in immunosuppressed and immunocompetent murine models

Cryptosporidiosis is one of the major causes of diarrhea in immunocompetent and immunocompromised patients. It is self-limited in immunocompetent individuals. However, in the immunocompromised it can cause life-threatening diarrhea and results in chronic malabsorption of fluids, vitamins and electrolytes resulting in wasting. Our study is concerned with assessing and comparing the efficacy of nitazoxanide (NTZ) alone and NTZ loaded chitosan nanoparticles (NTZ loaded CS NPs) in the treatment of experimental cryptosporidiosis using parasitological and histopathological parameters. One hundred mice were divided into 5 groups (20 mice each). Each group was divided into 2 subgroups according to the immune status [a-immunocompetent, b-immunosuppressed]. group 1: control (healthy), group 2: control infected by Cryptosporidium oocysts, group 3: infected treated by NTZ, group 4: infected then treated by NTZ loaded CS NPs and group 5: infected then treated by chitosan nanoparticles (CS NPs) alone. Treatment of Cryptosporidium infected mice with NTZ loaded on CS NPs resulted in the highest significant reduction in oocysts shedding in both immunocompetent and immunosuppressed groups followed by treatment with NTZ form then by treatment with CS NPs alone. The treatment with NTZ loaded CS NPs displayed a remarkable improvement of the histopathological changes of the intestine, liver and lung while NTZ treated group showed some improvement. Treatment with NTZ loaded CS NPs in murine cryptosporidiosis gave the best results as it caused marked reduction in fecal oocysts counts and improvement of histopathological changes in immunocompetent and immunosuppressed groups.

The determination of treatment effect of chitosan oligosaccharide in lambs with experimentally cryptosporidiosis

•

Chitosan oligosaccharide contributes to clinical improvement in lambs with experimentally cryptosporidiosis.

•

Chitosan oligosaccharide reduces C. parvum oocysts.

•

Chitosan oligosaccharide can be used in the treatment of cryptosporidiosis.

In this study, it was aimed to investigate the efficacy of chitosan oligosaccharide administrations in different doses of experimental infected lambs with Cryptosporidium parvum. 32 male lambs were used in the study and the lambs were divided into 4 groups with 8 lambs in each group. Groups 1, 2 and 3, twice a day, were administered chitosan oligosaccharide at a dose of 100, 500, and 1000 mg/kg for 7 days, respectively, with milk replacer. In group 4, lambs with cryptosporidiosis were subjected to normal feeding as control without drug administration. Clinical examinations of lambs were made before treatment (day 0) and on days 1, 3, 5 and 7 after treatment and 5 ml of blood was collected from vena jugularis for blood analysis of all lambs. Weight changes of lambs were recorded at 0, 7, 14, and 21 days. Stool specimens were collected pre-treatment (day 0) and on days 1, 3, 5, 7, 14 and 21 post-treatment to determine oocyst excretion of lambs with cryptosporidiosis. Lambs with a mean oocyte counts >10 after stool examination were included to the treatment. Changes in clinical hematology, blood gases and biochemical parameters were observed during the course of treatment, but these changes were limited. Weight loss was observed at 7th day according to 0th day the lambs with experimental cryptosporidiosis but gradually weight increase was observed at 14th and 21st days and these changes were similar in all groups. Oocyst excretion decreased in all groups during treatment. According to 0th day, there was a significant (p < 0.05) decrease in oocyte excretions in the third day in group 1 and 2, and in day 5 in the group 3 and 4. Significant changes (p < 0.05) were observed in oocyst excretions on the third and fifth days among the groups. As a result, in lambs with experimental cryptosporidiosis, chitosan oligosaccharide improved in clinical signs and stool character shorter than the positive control group and the administration of chitosan oligosaccharide at doses of 100, 500 and 1000 mg/kg for 7 days significantly reduced oocyst excretion but not enough to remove cryptosporidiosis completely.

Development of particulate drug formulation against C. parvum: Formulation, characterization and in vivo efficacy

This research aims towards developing an alternative therapy against Cryptosporidium parvum using bioadhesive paromomycin and diloxanide furoate-loaded microspheres. Microspheres were prepared using chitosan and poly(vinyl alcohol) and two types of cyclodextrins (β-CD and DM-β-CD) for the potential use of treating cryptosporidiosis. This pathogen is associated with gastrointestinal illness in humans and animals. Microparticle formulations were characterized in terms of size, surface charge, drug release and morphology. In vivo bioadhesion properties of CHI/PVA microspheres were also evaluated in mice. Finally, the in vivo efficacy of CHI/PVA microspheres against C. parvum was tested in neonatal mouse model. In this work, microspheres prepared by spray-drying showed spherical shape, diameters between 6.67±0.11 and 18.78±0.07μm and positively surface charged. The bioadhesion studies demonstrated that MS remained attached at +16h (post-infection) to the intestinal cells as detected by fluorescence. This finding was crucial taking use of the fact that the parasite multiplication occurs between 16 and 20h post-infection. The efficacy of treatment was determined by calculating the number of oocysts recovered from the intestinal tract of mice after 7days of post-infection. Mice receiving orally administered microspheres with and without drug exhibited significantly lower parasite loads compared with the control mice. Ultrastructural observations by TEM bring to light the uptake of smallest particles by enterocytes associated with conspicuous changes in enterocytic cells. Completely recovery of cell morphology was detected after 24h of first inoculation with MS. CHI/PVA microspheres appear to be a safe and simple system to be used in an anticryptosporidial treatment. The distinctive features of neonatal mice requires further work to determine the suppressive effect of this particulate delivery system on C. parvum attachment in other animal models.