Macroscopic quorum sensing sustains differentiating embryonic stem cells.

Cells can secrete molecules that help each other's replication. In cell cultures, chemical signals might diffuse only within a cell colony or between colonies. A chemical signal's interaction length-how far apart interacting cells are-is often assumed to be some value without rigorous justifications because molecules' invisible paths and complex multicellular geometries pose challenges. Here we present an approach, combining mathematical models and experiments, for determining a chemical signal's interaction length. With murine embryonic stem (ES) cells as a testbed, we found that differentiating ES cells secrete FGF4, among others, to communicate over many millimeters in cell culture dishes and, thereby, form a spatially extended, macroscopic entity that grows only if its centimeter-scale population density is above a threshold value. With this 'macroscopic quorum sensing', an isolated macroscopic, but not isolated microscopic, colony can survive differentiation. Our integrated approach can determine chemical signals' interaction lengths in generic multicellular communities.

Business case for psychosocial interventions in clinics: potential for decrease in treatment discontinuation and costs.

RESEARCH QUESTION: From a value-based healthcare (VBHC) perspective, does an assessment of clinical outcomes and intervention costs indicate that providing cognitive behavioural therapy (CBT) or mindfulness to women seeking fertility treatment add value compared with no such intervention? DESIGN: Proof-of-concept business case based on a VBHC perspective that considers clinical outcomes and costs. Potential effects on psychological and fertility outcomes were based on existing research. Cost outcomes were estimated with a costing model for the Dutch fertility treatment setting. RESULTS: Thirty-two studies were identified; 13 were included. Women who received CBT had 12% lower anxiety, 40% lower depression and 6% higher fertility quality of life; difference in clinical pregnancy rates was six percentage points (CBT [30.2%]; control [24.2%]); difference in fertility discontinuation rates was 10 percentage points (CBT [5.5%]; control [15.2%]). Women who received training in mindfulness had 8% lower anxiety, 45% lower depression and 21% higher fertility quality of life; difference in mean clinical pregnancy rate was 19 percentage points (mindfulness [44.8%]; control [26.0%]). Potential total cost savings was about €1.2 million per year if CBT was provided and €11 million if mindfulness was provided. Corresponding return on investment for CBT was 30.7%, and for mindfulness 288%. Potential cost benefits are influenced by the assumed clinical pregnancy rates; such data related to mindfulness were limited to one study. CONCLUSIONS: The provision of CBT or mindfulness to women seeking fertility treatment could add value. Higher quality primary studies are needed on the effect of mindfulness on clinical pregnancy rates.

Modeling cell-cell communication for immune systems across space and time.

Communicating is crucial for cells to coordinate their behaviors. Immunological processes, involving diverse cytokines and cell types, are ideal for developing frameworks for modeling coordinated behaviors of cells. Here, we review recent studies that combine modeling and experiments to reveal how immune systems use autocrine, paracrine, and juxtacrine signals to achieve behaviors such as controlling population densities and hair regenerations. We explain that models are useful because one can computationally vary numerous parameters, in experimentally infeasible ways, to evaluate alternate immunological responses. For each model, we focus on the length-scales and time-scales involved and explain why integrating multiple length-scales and time-scales in a model remain challenging. We suggest promising modeling strategies for meeting this challenge and their practical consequences.