Pharmacokinetics and pharmacodynamics of methyl proscillaridin in healthy man

Mathematical modelling of clonal reduction therapeutic strategies in acute myeloid leukemia

Over the years, the overall survival of older patients diagnosed with acute myeloid leukemia (AML) has not significantly increased. Although standard cytotoxic therapies that rapidly eliminate dividing myeloblasts are used to induce remission, relapse can occur due to surviving therapy-resistant leukemic stem cells (LSCs). Hence, anti-LSC strategies have become a key target to cure AML. We have recently shown that previously approved cardiac glycosides and glucocorticoids target LSC-enriched CD34+ cells in the primary human AML 8227 model with more efficacy than normal hematopoietic stem cells (HSCs). To translate these in vitro findings into humans, we developed a mathematical model of stem cell dynamics that describes the stochastic evolution of LSCs in AML post-standard-of-care. To this, we integrated population pharmacokinetic-pharmacodynamic (PKPD) models to investigate the clonal reduction potential of several promising candidate drugs in comparison to cytarabine, which is commonly used in high doses for consolidation therapy in AML patients. Our results suggest that cardiac glycosides (proscillaridin A, digoxin and ouabain) and glucocorticoids (budesonide and mometasone) reduce the expansion of LSCs through a decrease in their viability. While our model predicts that effective doses of cardiac glycosides are potentially too toxic to use in patients, simulations show the possibility of mometasone to prevent relapse through the glucocorticoid's ability to drastically reduce LSC population size. This work therefore highlights the prospect of these treatments for anti-LSC strategies and underlines the use of quantitative approaches to preclinical drug translation in AML.

Traditional medical uses of Drimia species in terms of phytochemistry, pharmacology and toxicology

Drimia genus includes plants that used from ancient time for various ailments such as dropsy, respiratory ailment, bone and joint complications, skin disorders, epilepsy and cancer. Toxic properties of some Drimia species also were noted by ancient scientists and these plants have been traditionally used for rat control. Bufadienolides have been identified as the main constituents in the genus of Drimia. Phenolics, sterols, protein and some of other phytochemicals have been also isolated from these plants. Pharmacological and clinical studies have strongly approved their effect on cardiovascular system. Extracts and compounds isolated from Drimia species showed biological activities such as antibacterial, antifungal, antiviral, antioxidant, anti-inflammatory and insecticidal effects through several in vivo and in vitro studies. Moreover, cytotoxic and antitumor activities which may be related to bufadienolide content of these plants have been considered by many researchers. Traditional therapeutic values of these plants for treating respiratory and rheumatic ailments as well as skin disorders are needed to be validated through more researches. Toxic effects of these plants and isolated compounds have been investigated through several in vivo studies. Drimia plants and their isolated compounds have narrow therapeutic index, so patients should be prohibited from applying these plants without medical supervision and should be informed about the main intoxication symptoms before starting treatment. Moreover, interaction of Drimia plants with other constituents of traditional herbal mixtures as well as chemical and biological modalities for reducing toxicity of bufadienolide compounds can be subjected for future studies.

Digoxin, whole body potassium and the electrocardiogram

Previous studies have shown a significant linear relationship between the PTQ-index (a combination function of the PR-interval, corrected QT-time and T-wave depression in the ECG) and serum digoxin level in chronically treated patients. The relationship was confirmed in the present study and it was shown that it could be changed by concomitant administration of potassium chloride or furosemide, and that there was marked interindividual variation in response. An inverse linear relationship between PTQ-index and whole body potassium was found during chronic administration of a constant daily dose of digoxin, but no such relationship was found for serum potassium.