Intercellular diffusion

Gap junctions are specialized intercellular channels directly connecting the cytoplasm of adjacent cells. They allow for electrical and metabolic coupling in many kinds of tissues; in the vascular wall they enable conduction of electrical signals conveying information along the vascular tree, and in the heart gap junctions underlie the fast spread of depolarization preceding contraction. In our lab we apply a dye-based assay with the potential to monitor drug-modulating effects on gap junction permeability. The main interest has been in modeling this assay mathematically in order to estimate the permeability in quantitative terms.

Vasomotion is spontaneous oscillation in the tonus of the smooth muscles in the arteriolar walls giving rise to 0.1 Hz diameter fluctuations. Its occurrence is known to correlate with diseases such as hypertension and diabetes. The microcirculation of the retina provides an unique opportunity to observe vasomotion without eksperimental intervention. The current work is in quantifying vasomotion in recordings of the retina by using advanced image analysis, and correlate these findings with the state of a given disease in order to develop new diagnostic and prognostic measures.

Currently we are working on the following projects

Estimation of the effective intercellular diffusion coefficient in cell monolayers coupled by gap junctions

This project is concerned with a recently based assay to study gap junction permeability. It is based on electroporation of a fluorescent dye into a large number of Connexin 43 expressing cells. The aim of this project is to make a mathematical model describing the observed spread of dye according to Fick's law.

Fluorescence micrograph of a monolayer of C6 cells coupled by gap junctions. The left part of the monolayer is loaded with the fluorescent dye Lucifer Yellow


A hexagonal grid is placed on top of the original fluorescence micrograph to enable a 2-dimensional simulation.



Vasomotion in the microvascular network of the retina

Example of the vessel network in the human retina.




If you want to know more about these research projects, please contact Niels Erik Olesen.