Revascularization of Transplanted Pancreatic Islets and Role of the Transplantation Site

Table 1

Characterization of different islet transplant sites as published in the literature.

Site	Local environment challenges	Glyco-insular response	Portal versus systemic insulin delivery	Immune exposure	Surgical accessibility	Preclinical evidence	Clinical evidence
Intraportal	++	+++; Mimics physiological insulin release	?	0; IBMIR	+++; Minimally invasive	[58, 74, 76, 81, 91, 105, 115–117]	[118–120]
Renal subcapsule	+; Hypoxia	0; Need many islets	Systemic	++	0; invasive	[74, 76, 91, 115, 116, 121, 122]; Good rodent evidence	[75]
Omental pouch	+; Hypoxia	+	Portal	++	++	[85, 123, 124]
Gastrointestinal wall	++	+++; Physiological glucose entry site	Portal	++	+++; Endoscopic access	[92–94]
Subcutaneous	+; Prevascularization required	+	Systemic	+	+++	[60, 125–127]
Muscle	+; Prevascularization; required	+	Systemic	+	+++	[125, 128–130]	[110, 131]
Bone marrow	+++; Highly vascular	+	Systemic	+	0; Invasive	[108, 109, 132]
Adipose	++; Vascular	+	Systemic	+	+++	[111, 112]
Pancreas	+++; Native site	+++; Native site	Portal	+	0; Invasive	[91, 133]
Spleen	+++; Highly vascular	+++	Portal	0; IBMIR	0; Hemorrhagic risk	[76, 134–137]; Good canine evidence	[124]
Lung (intravenous)	+; Venous supply is hypoxic	++	Systemic	0; IBMIR	0; Widely dispersed	[138, 139]
Brain	+++; Highly vascular	++	Systemic	+++; Immune-privileged	0; Cerebral ischemia risk	[101, 102]
Testis	+	+	Systemic	+++; Immune privileged	++	[97, 98, 140]
Thymus	+	+	Systemic	+++; Immune-privileged	++	[104–107]	[141]
Celiac artery	+; Infarct in terminal end-arteries	++	Portal	+; IBMIR	+	[117]

+++: excellent ++: good +: neutral 0: disadvantage.