Pancreatic Islet Blood Flow Dynamics in Primates

Summary Blood flowregulation in pancreatic isletsis critical for function but poorly understood. Here, we establish an in vivo imaging platform in a non-human primatewhere isletstransplanted autologously into the anterior chamber of the eye are monitored non-invasively and longitudinally at single-cell resolution. Engrafted isletswere vascularized and innervated and maintained the cytoarchitectureof in situ isletsin the pancreas. Blood flowvelocity in the engrafted isletswas not affected by increasing blood glucose levels and/or the GLP-1R agonist liraglutide. However, islet blood flowwas dynamic in nature and fluctuated in various capillaries. This was associated with vasoconstriction events resembling a sphincter-like action, most likely regulated by adrenergic signaling. These observations suggest a mechanism in primate isletsthat diverts blood flowto cell regions with higher metabolic demand. The described imaging technologyapplied in non-human primate isletsmay contribute to a better understanding of human isletpathophysiology.