Stem cell transplantation has recently demonstrated a significant therapeutic efficacy in various diseases. Multilineage-differentiating stress-enduring (Muse) cells are stress-tolerant endogenous pluripotent stem cells that were first reported in 2010. Muse cells can be found in the peripheral blood, bone marrow and connective tissue of nearly all body organs. Under basal conditions, they constantly move from the bone marrow to peripheral blood to supply various body organs. However, this rate greatly changes even within the same individual based on physical status and the presence of injury or illness. Muse cells can differentiate into all three-germ-layers, producing tissue-compatible cells with few errors, minimal immune rejection and without forming teratomas. They can also endure hostile environments, supporting their survival in damaged/injured tissues. Additionally, Muse cells express receptors for sphingosine-1-phosphate (S1P), which is a protein produced by damaged/injured tissues. Through the S1P–S1PR2 axis, circulating Muse cells can preferentially migrate to damaged sites following transplantation. In addition, Muse cells possess a unique immune privilege system, facilitating their use without the need for long-term immunosuppressant treatment or human leucocyte antigen matching. Moreover, they exhibit anti-inflammatory, anti-apoptotic and tissue-protective effects. These characteristics circumvent all challenges experienced with mesenchymal stem cells and induced pluripotent stem cells and encourage the wide application of Muse cells in clinical practice. Indeed, Muse cells have the potential to break through the limitations of current cell-based therapies, and many clinical trials have been conducted, applying intravenously administered Muse cells in stroke, myocardial infarction, neurological disorders and acute respiratory distress syndrome (ARDS) related to novel coronavirus (SARS-CoV-2) infection. Herein, we aim to highlight the unique biological properties of Muse cells and to elucidate the advantageous difference between Muse cells and other types of stem cells. Finally, we shed light on their current therapeutic applications and the major obstacles to their clinical implementation from laboratory to clinic.

Cancer is a disease that is characterized by uncontrolled cell proliferation. Breast cancer is the most prevalent cancer among women. Ginger oil is a natural cancer fighter and anti-oxidant. However, the minimal absorption of ginger oil from the gastrointestinal tract accounts for its limited medicinal efficacy. The present study was designed to evaluate the efficacy of a nanoemulsion preparation of ginger oil on its oral bioavailability and in vivo anti-cancer efficacy. Ginger oil nanoemulsion was prepared by a high-pressure homogenization technique using different surfactants (Tween 20, 40, and 80). The prepared formulations were evaluated for droplet size, polydispersity index (PDI), zeta potential (ZP), pH, viscosity, and stability by calculating the creaming index percentage. The best formulation was evaluated for shape by TEM. The antitumor activity of the best nano-formulation was determined in comparison with the free oil using the in vivo Ehrlich solid tumor (EST) model. The prepared ginger oil nanoemulsion formulations exhibited acceptable droplet size in the range from 56.67 ± 3.10 nm to 357.17 ± 3.62 nm. A PDI of less than 0.5 indicates the homogeneity of size distribution. The oil globules possessed a negative charge ranging from −12.33 ± 1.01 to −39.33 ± 0.96 mV. The pH and viscosity were in the acceptable range. The TEM image of the best formulation appeared to be spherical with a small size. The ginger oil nanoemulsion reduced in vivo tumor volume and weight, extended animals’ life span, and ameliorated liver and kidney function in EST-bearing mice. These effects were superior to using free ginger oil. Collectively, the present study demonstrated that the ginger oil nanoemulsion improved oral absorption with a subsequent enhancement of its anti-proliferative efficacy in vivo, suggesting a nano-formulation of ginger oil for better therapeutic outcomes in breast cancer patients.