University of Mississippi Oxford, Mississippi, United States
Purpose: Immulina is a high-molecular weight preparation of Arthrospira platensis extracted with a patented aqueous alcohol extraction method. Previous studies have characterized its major immune enhancing component is tri-acylated lipoproteins which shows hydrophobic nature and low aqueous solubility. Animal studies of Immulina conducted rely on using a modified research chow in which Immulina powder was mixed with a chemically modified chow-AIN93M and be orally consumed by mice. The dosing regimen was estimated based on the average daily food intake of a group of mice. This mixed diet allowed animals to have continues access of Immulina rather than one-time dosage usually applied to humans in clinical trials. Besides, mixed-diet was hard to accurately quantitate the daily dosage. Here, we aim to prepare an aqueous formulation of Immulina (i.e., nano-Immulina) to allow an accurate measurement of daily dosage in individual animals and to mimic the administration regimen in real life scenario. And apply the aqueous formulation to evaluate the anticancer effect of Immulina in a B-16 melanoma mouse model. Methods: Here, nano-Immulina was developed using an ultrasonication method and the nanostructure was characterized by its size distribution. Nano-Immulina was lyophilized and the dissolution study was conducted to verify the dissolution rate and biological activity after lyophilization. The mRNA and protein expression levels of typical pro-inflammatory cytokines were determined by real-time PCR and ELISA in human THP-1 cells, mouse Bone marrow derived dendritic cells (BMDCs), or mouse Bone marrow derived macrophages (BMDMs) after exposed to nano-Immulina in vitro. The anticancer effect of Immulina was evaluated using a B-16 melanoma mouse model. Results: We observed Immulina forms nanostructure in PBS with around 300 nm mean particle size. Lyophilization of nano-Immulina successfully preserved the nanostructure without affecting the biological activity. The lyophilized formulation showed an improved water solubility and a fast release profile. In addition, nano-Immulina induced pro-inflammatory cytokine mRNA expression and protein production in both human and mouse cells. Moreover, mice treated with nano-Immulina exhibit slower growth of B-16 melanoma. Conclusion: This study first demonstrated that nano-Immulina is a proper oral formulation for accurately evaluate the efficacy of Immulina in mice and can be used in the future clinical trial. Secondly, it revealed that administration of Immulina showed anticancer activity.
