In vivo imaging of human pancreatic microcirculation and pancreatic tissue injury in clinical pancreas transplantation.

Pancreatitis remains to be a major complication following clinical pancreas transplantation. We performed orthogonal polarized spectral (OPS) imaging for direct in vivo visualization and quantification of human pancreatic microcirculation in six healthy donors for living donor liver transplantation and 13 patients undergoing simultaneous pancreas-kidney transplantation. We further determined the impact of microvascular dysfunction during early reperfusion on pancreatic graft injury. Exocrine and endocrine pancreatic impairment was determined by analysis of serum lipase, amylase and C-peptide levels. Compared to normal pancreas in liver donors (homogeneous acinar perfusion) functional capillary density (FCD) and capillary red blood flow velocity of reperfused grafts were significantly decreased. Elevated CRP concentrations on day 2 post-transplant and serum lipase and amylase levels determined on days 4-5 significantly correlated with microvascular dysfunction during the first 30 min of graft reperfusion. Post-transplant serum C-peptide also correlated significantly with pancreatic capillary perfusion. OPS imaging allows to intra-operatively assess physiologic pancreatic microcirculation and to determine microcirculatory impairment during early graft reperfusion. This impairment correlated with the manifestation of post-transplant dysfunction of both exocrine and endocrine pancreatic tissue. OPS imaging may be used clinically to determine the efficacy of interventions, aiming at attenuating microcirculatory impairment during the acute post-transplant reperfusion phase.