Colonic enteric nervous system in patients with familial amyloidotic neuropathy

The colonic enteric nervous system was investigated in autopsy specimens fr om 12 patients with familial amyloidotic neuropathy (FAP) and 9 controls. T he infiltration of amyloid deposits in the enteric nervous system was studi ed by double staining for amyloid and nerve elements. The myenteric plexus was immunostained for protein gene product (PGP) 9.5, vasoactive intestinal peptide (VIP), substance P and nitric oxide synthase (NOS). The immunostai ned nerve elements were quantified by computerised image analysis. Double s taining revealed that there was no amyloid infiltration in the ganglia, or in the nerve fibres in the colonic enteric nervous system of FAP patients. The relative volume density of PGP 9.5-immunoreactive nerve fibres in both the circular and the longitudinal muscle layers in FAP patients did not dif fer significantly from that of controls. The relative volume density of VIP -immunoreactive nerve fibres in the circular muscle layer was significantly decreased in FAP patients compared with controls, but not in the longitudi nal layer. The number of VIP-immunoreactive neurons/mm(2) myenteric ganglia was significantly decreased in FAP patients. There were no statistical dif ferences in the relative volume density for substance P- and NOS-immunoreac tive nerve fibres between FAP patients and controls, nor was there any diff erence between FAP patients and controls regarding the number of NOS- and s ubstance P-immunoreactive neurons/mm2 myenteric ganglia. It is concluded th at the colonic enteric nervous system as a whole is intact and is not damag ed by amyloid infiltration. The present observation of a reduction of VIP-i mmunoreactive nerve fibres and neurons in myenteric plexus of FAP patients might be one of the factors that contribute to the motility disorders seen in FAP patients.