We have identified a new class of steroid hormone receptors that are associated with the cell membrane. They transmit their signals to the cells through pathways that are used by classical membrane receptors. Some of the effects of the steroid hormones that are mediated by these membrane receptors are directly on gene transcription through these pathways. Activation of the membrane receptors can also result in indirect effects by modifying the activity of the traditional steroid hormone receptors. One of these receptors is for estrogen and is active only in cells that come from female animals and humans. This is particularly exciting because it helps to explain why male and female cells respond in different ways to the same signals.
We are using nanotechnology to examine how specific microtopographic structural features of a material regulate how cells respond to hormones like estrogen. This work is important because many devices used for dental and orthopaedic reconstruction are used in post-menopausal women, yet we know very little about how these patients react to the surfaces of these materials. Using these novel substrates, we can now determine which structural features of a material cause cells to behave in specific ways. We know that female bone cells, for example, react to microrough titanium implant surfaces with an increased response to estrogen and this is further enhanced when nanotopographic features are superimposed on the microtopography. Thus, one can envision designing improved implants that are more effective in bone in post-menopausal females where circulating levels of estrogen are reduced.
We are now developing new methods for delivering multipotent stem cells for craniofacial reconstruction and treatment of traumatic injuries. Using patent pending technologies to protect the cells while stimulating their differentiation along specific tissuelines, we are able to deliver the cells percutaneously. Our goal is to provide the surgeon with a stable and quantifiable supply of the patient's own cells in a form that can be easily used, in many cases without requiring surgery.