Brian Roman, PhD
Q: What do you get when you put molecular biologists, bioengineers, physiologists and veterinary experts in the same room with cutting edge biological and in vivo imaging equipment?
A: The Molecular and Physiological Imaging Laboratory in the Department of Radiology.
The laboratory is divided into five primary areas based on function and associated equipment to support research in modern molecular imaging, particularly magnetic resonance, as applied to diabetes and cardiovascular research. One of the lab’s primary focuses is the development of MRI techniques to all for MR functional imaging of the pancreatic beta cell in vitro and in vivo. It is our contention that is imperative to be able to image in real time beta cell activation and hopefully the release of insulin. This would provide us an approach for monitoring normal as well as pathological beta cell activity so that interventional strategies could be implemented to ameliorate the process of diabetes.
Our lab has been using manganese (Mn) as a calcium analog and MRI T1 relaxation agent in the presence of glucose activated ßTC3, rodent and human islets, and rodent pancreas. Our predication was that during beta cell depolarization caused by elevated serum glucose, Mn would be taken up into the beta cell and therefore “tag” the beta cell(s) by affecting the T1 relaxation time of the intracellular water molecules. On a T1 weighted MR image this uptake of Mn would appear as bright contrast and be interpreted as direct ß-cell activation. Figure 1 illustrates this phenomenon in isolated rodent and human islets stimulated with high extracellular glucose. Using a 11.7T MRI microscope and homebuilt RF coils, we are able to obtain approximately 15um in plane resolution of isolated rodent and human islets. We have taken this technique most recently to the in vivo intact rodent pancreas and have many challenges which we continue to overcome. Figure 2 illustrates the rodent pancreas before and following a glucose challenge. You can see the change in pancreatic contrast which is directly correlated to beta cell activation and insulin release. Our lab pioneered this effort and with our collaborators in Endocrinology and Transplant Surgery we hope to continue with even greater success and contributions to the understanding of Diabetes.
In order to conduct this research, we have put together a diverse array of technologies. Located in the imaging laboratory is an off site image processing station which runs Bruker Paravision software which is used for processing data obtained on the state of the art 9.4T MRI animal scanner. The molecular biology laboratory is dedicated to the design, construction and testing of DNA constructs used for creation of transgenic animal models. Equipment includes a real time quantitative PCR machine as well as incubator shakers and electrophoresis equipment. The animal physiology laboratory is setup for performing small animal surgeries (non- and survival) as well as obtaining physiological measurements of cardiac function in situ. The equipment involved includes a Zeiss surgical microscope, Harvard small animal ventilator, anesthesia system, micro-interventricular pressure and volume catheters as well as a physiological data acquisition and analysis computer system. Cell culture, labeling and fluorescence imaging experiments are conducted in another laboratory. This laboratory has a biosafety level II cabinet, cell incubator, Zeiss fluorescence microscope and digital imaging system for acquisition and analysis. The apparatus for general biochemistry are housed in the equipment laboratory and include a UV spectrophotometer, microplate reader, Sorvall RC-6 High speed ultracentrifuge and Bio-Rad gel documentation and analysis workstation.
Figure 1: Control (left) vs Stimulated (right) rodent islets.
