Quantification of acetylcholinesterase-positive structures in human thymusduring development and aging

Acetylcholinesterase (AChE) localization in the human thymus has been studi ed by biochemical and morphological methods during development and aging. T he occurrence, the amount and the distribution of acetylcholinesterase and the changes with age were examined in 24 human thymuses. The whole human th ymus was removed during autopsies in males of the following age-groups: pre natal of six months, new-born, infant, young, adult and elderly. The thymuses were weighed, measured and dissected: the microanatomical deta ils were stained with Eosin-orange, nervous structures were identified by m eans of Bodian's method. Protein content was determined with biochemical me thods. Histoenzymatical and biochemical demonstration of acetylcholinestera se was performed. The morphological results obtained were submitted to quan titative image analysis. Our results show that the thymic microenvironment changes with age; moreover, an increase of acetylcholinesterase-positive st ructures can be observed with age. Biochemical results are in agreement wit h morphological results and both are confirmed by the outcome of quantitati ve analysis of images. Acetylcholinesterase activity in human thymus may pl ay a key role in thymic functions. (C) 1999 Elsevier Science Ltd. All right s reserved.