123 I‐MIBG scintigraphy suggests functional sympathetic reinnervation in human renal allografts (687.1)

After kidney transplantation, sympathetic renal nerves may reinnervate the allograft, but its functional significance is unknown. 123 I‐metaiodobenzylguanidine ( 123 I‐MIBG) scintigraphy determines organ specific sympathetic innervation (uptake) and activity (washout rates, WORs). Therefore we applied 123 I‐MIBG scintigraphy to assess the functionality of sympathetic nerves in human renal allografts. We studied 5 patients with a median allograft survival of 20 years (range 11‐36), creatinine clearance 89 ml/min (56‐118). Their immunosuppressive drug regimen consisted of azathioprine and prednisolone. None of them was treated with either alpha‐ or beta‐blocking agents. After intravenous administration of 185 MBq 123 I‐MIBG, scintigrams were made at 15 min and 4 hr postinjection (p.i.) and a CT scan was made for anatomical localization of the tracer. Uptake was calculated as % of injected dose 123 I‐MIBG. WORs in the myocardium, native left kidney and renal allograft were deducted from 15 min and 4 hr scintigrams. For WORs the relative uptake was used in relation to non‐specific uptake (i.e. mediastinum). Median % injected dose uptake in the myocardium, native left kidney and renal allograft was 3.7, 5.5, 3.8% at 15min p.i. and 3.3, 4.8 and 1.6% at 4hr p.i. respectively. WORs were 4.8, 6.7 and 26%. These data suggest some functional sympathetic reinnervation in long surviving human renal allografts. The use of renal 123 I‐MIBG scintigraphy should be validated and functional significance of this sympathetic reinnervation in renal allografts will be further studied. Grant Funding Source : Dutch Kidney Foundation (IP 11‐40)