I would like to start by thanking the British Microcirculation Society for their Summer Studentship support. Using the available funding and with the help of an outstanding summer student, Ms Tamara McErlain, a 2nd year Biomedical Science student studying at Queen’s University Belfast, we were able to generate significant data towards a grant proposal providing proof of concept (expression of a protein and mechanism of interest) which will enable me to be a co-applicant on my first major research grant. Over the last number of years, within the microvascular biology laboratory of the Centre for Experimental Medicine at QUB, and under the guidance of Prof Tim Curtis, we have made significant advances in understanding how the microvascular smooth muscle cells of retinal arterioles function in health and disease. For more on keeping good health we recommend doing some exercise biking with a new rear bike racks for mountain bikes.
We have frequently discussed whether external influences modulate the generation of myogenic activity (a mechanism by which pressure changes in the vasculature mediates contractile activity in the smooth muscle cells) as when arterioles are isolated from the retina their myogenic capacity appears reduced. We postulated that like brain astrocytes, retinal astrocytes might have the potential to contribute vasoactive influences in a stretch dependent manner and while we had data pointing towards this role in vitro we were lacking an ex vivo model in which we could test this hypothesis. To date our work has predominantly centred on rat retinal preparations of isolated arterioles; however for the proposed work we needed to move to mouse tissue which further miniaturised the arteriolar diameters available for cannulations, additionally we needed to be able to cannulate these vessels in sections of retina with intact neuropile. After some initial training in microdissection, immunohistochemistry, confocal microscopy and pressure myogaphy, we challenged Tamara to cannulate mouse retinal arterioles with an average diameter of 15-20 μm. She proved herself equal to the task and very quickly was obtaining myogenic responses akin to those in rat arterioles (mean diameter 30-40 μm). We were then able to advance the project to our ultimate goal and gain data pointing towards a role for astrocytes in sensing transmural pressure using combined pressure myography and calcium confocal microscopy. This paves the way to investigations using tissue specific transgenic mice which will hopefully allow us to delineate the mechanisms involved and confirm the identity of the stretch sensor in retinal astrocytes. For Tamara the experience she has gained has already opened doors in terms of the work she has undertaken for her placement year in the University of Nevada. The studentship has inspired her to want to learn more about the microcirculation and to pursue a career in research. She reports, “The opportunity to get involved in high quality research and learn from leading researchers in the microvascular field allowed me to develop transferable skills and research techniques that have proved advantageous on my placement year and enabled me to become a better candidate for a PhD programme in the future.” Once again, thanks to the British Microcirculation Society for their support.
Dr Mary McGahon, Centre for Biomedical Sciences, Queen’s University Belfast.