Photoacoustic imaging of angiogenesis in a subcutaneous islet transplant site in a murine model.
Islet transplantation (IT) is an established clinical therapy for select patients with type-1 diabetes. Clinically, the hepatic portal vein serves as the site for IT. Despite numerous advances in clinical IT, limitations remain, including early islet cell loss posttransplant, procedural complications, and the inability to effectively monitor islet grafts. Hence, alternative sites for IT are currently being explored, with the subcutaneous space as one potential option. When left unmodified, the subcutaneous space routinely fails to promote successful islet engraftment. However, when employing the previously developed subcutaneous “deviceless” technique, a favorable microenvironment for islet survival and function is established. In this technique, an angiocatheter was temporarily implanted subcutaneously, which facilitated angiogenesis to promote subsequent islet engraftment. This technique has been employed in preclinical animal models, providing a sufficient means to develop techniques to monitor functional aspects of the graft such as angiogenesis. Here, we utilize photoacoustic imaging to track angiogenesis during the priming of the subcutaneous site by the implanted catheter at 1 to 4 weeks postcatheter. Quantitative analysis on vessel densities shows gradual growth of vasculature in the implant position. These results demonstrate the ability to track angiogenesis, thus facilitating a means to optimize and assess the pretransplant microenvironment.
University of Alberta, Department of Electrical and Computer Engineering, Edmonton T6G 2V4, Canada.
Wei
W
Shi
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, Canada.
Rena
R
Pawlick
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, CanadacUniversity of Alberta, Department of Surgery, Edmonton T6G 2C8, Canada.
Antonio
A
Bruni
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, Canada.
Yasmin
Y
Rafiei
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, Canada.
Andrew R
AR
Pepper
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, CanadacUniversity of Alberta, Department of Surgery, Edmonton T6G 2C8, Canada.
Boris
B
Gala-Lopez
University of Alberta, Department of Electrical and Computer Engineering, Edmonton T6G 2V4, Canada.
Min
M
Choi
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, CanadacUniversity of Alberta, Department of Surgery, Edmonton T6G 2C8, Canada.
Andrew
A
Malcolm
University of Alberta, Department of Electrical and Computer Engineering, Edmonton T6G 2V4, Canada.
Roger J
RJ
Zemp
University of Alberta, Alberta Diabetes Institute, Edmonton T6G 2C8, CanadacUniversity of Alberta, Department of Surgery, Edmonton T6G 2C8, Canada.
A M James
AM
Shapiro
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000628:therapy*; D004195:Disease Models, Animal; D006801:Humans; D016381:Islets of Langerhans Transplantation / Q000000981:diagnostic imaging* / Q000379:methods*; D051379:Mice; D018919:Neovascularization, Physiologic; D061088:Photoacoustic Techniques