Background: Among the elderly ageing is not associated with an overall loss of myenteric neurons in the colon yet the incidence of gastrointestinal disorders such as constipation increases. We investigated the influence of old age on the pattern of distribution of a specific group of neurons, namely calretinin-immunoreactive (IR) enteric neurons in the myenteric (MP) and submucous (SMP) plexus of human ascending (AC) and descending (DC) colon and further examined their fibre density in the mucosa. Methods: Macroscopically normal AC and DC colon were obtained from patients aged 22 – 91 years undergoing lower bowel cancer resection. These were immunolabelled with calretinin antibody to identify calretinin-IR enteric neurons and fibres. Results: In adults, the number of calretinin-immunoreactive cell bodies per ganglion was greater in the SMP than MP but with similar density in the AC and DC. In both age groups, the densities of calretinin-IR enteric neurons were similar in the MP of the AC (adult: 1.2 ± 0.3 x 10-3 ; elderly: 0.9 ± 0.2 x 10-3 per mm2 of plexus) and DC (respectively 1.4 ± 0.2 x 10-3; 1.3 ± 0.3 x 10-3 per mm2 of plexus). Among the elderly, the density of calretinin-IR neurons and fibres were decreased in the SMP of AC but not clearly in the DC. In the mucosal layer of both AC and DC, the decrease in density of fibres was greater in the AC compared to DC. Conclusion: The ageing of the human colon does not result in the loss of calretinin-immunoreactive neurons and fibres in the MP but losses occur in the submucosa of AC and within the mucosa of both AC and DC. |