Visualization and Modeling of the In Vivo Distribution of Mesenchymal Stem Cells

Possible Kidney Complications after Application of Cell Technologies for the Repair of the Resected Liver

The state of rat kidneys after injection of bone marrow multipotent stromal cells (MSC) labeled with Vybrant CM-Dil into intact or resected liver was studied by fluorescence microscopy. The main structural changes in the kidneys after MSC injection into intact and partially resected liver manifested as granular dystrophy and necrobiotic/necrotic changes in single epithelial cells of the distal tubules and collecting ducts, thrombosis of some vessels, progression of an ascending urinary tract infection (detection of dust-like fluorescent objects), which can be due to the immunomodulating or even immunosuppressive influence of MSC and their detritus. MSC injected into the intact or resected liver, as well as the products of their degradation were not detected in the kidneys at all terms of observation. After injection of MSC into partially resected liver, manifestations of bacterial contamination of the renal medulla appeared later. The injection of MSC into the liver can be complicated by thrombosis of the renal vessels, which should be taken into account when using this administration route in the cell therapy.

Anionic Long-Circulating Quantum Dots for Long-Term Intravital Vascular Imaging

A major impediment to the long-term in vivo vascular imaging is a lack of suitable probes and contrast agents. Our developed mercaptosuccinic acid (MSA) capped cadmium telluride/cadmium sulfide (CdTe/CdS) ultrasmall quantum dots (QDs) have high fluorescent quantum yield, long fluorescence lifetime and long half-life in blood, allowing high resolution long-term intravital vascular imaging. In this study, we showed that these QDs can be used to visualize the in vivo the vasculature in normal and cancerous livers in mice using multiphoton microscopy (MPM) coupled with fluorescence lifetime imaging (FLIM), with cellular resolution (~1 µm) up to 36 h after intravenous injection. Compared to highly regulated and controlled sinusoids in normal liver tissue, disordered, tortuous, and immature neovessels were observed in tumors. The utilized imaging methods have great potential as emerging tools in diagnosis and monitoring of treatment response in cancer.

The role of cellular reactive oxygen species in cancer chemotherapy

Most chemotherapeutics elevate intracellular levels of reactive oxygen species (ROS), and many can alter redox-homeostasis of cancer cells. It is widely accepted that the anticancer effect of these chemotherapeutics is due to the induction of oxidative stress and ROS-mediated cell injury in cancer. However, various new therapeutic approaches targeting intracellular ROS levels have yielded mixed results. Since it is impossible to quantitatively detect dynamic ROS levels in tumors during and after chemotherapy in clinical settings, it is of increasing interest to apply mathematical modeling techniques to predict ROS levels for understanding complex tumor biology during chemotherapy. This review outlines the current understanding of the role of ROS in cancer cells during carcinogenesis and during chemotherapy, provides a critical analysis of the methods used for quantitative ROS detection and discusses the application of mathematical modeling in predicting treatment responses. Finally, we provide insights on and perspectives for future development of effective therapeutic ROS-inducing anticancer agents or antioxidants for cancer treatment.