SPACE BALLS STEREOLOGY FULL
This study demonstrates that: 1) counter to previous evidence, under certain conditions the aged striatum can support robust survival of grafted DA neurons and 2) unknown factors associated with the aged striatum result in inferior integration of graft and host, and continue to present obstacles to full therapeutic efficacy of DA cell-based therapy in this model of aging.This article needs additional citations for verification.
![space balls stereology space balls stereology](https://royalsocietypublishing.org/cms/asset/2cbbe55a-b724-4bb8-bf3c-3d44cadc1241/rsif20210140f03.jpg)
Despite robust survival of grafted neurons in aged rats, reinnervation of striatal neurons remained inferior and amelioration of levodopa-induced dyskinesias (LID) was delayed or absent.
![space balls stereology space balls stereology](https://www.mdpi.com/crystals/crystals-10-00697/article_deploy/html/images/crystals-10-00697-g010.png)
Young (3 months), middle-aged (15 months), and aged (22 months) parkinsonian rats were grafted with proportionately increasing numbers of embryonic ventral mesencephalic (VM) cells to evaluate whether the limitations of the graft environment in subjects of advancing age can be offset by increased numbers of transplanted neurons. To help understand the capacity of the aged, parkinsonian striatum to be remodeled with new DA terminals, we used a grafting model and examined whether increasing the number of grafted DA neurons in aged rats would translate to enhanced behavioral recovery. In PD patients and rodent models of PD, advanced age is associated with inferior symptomatic benefit following intrastriatal grafting of embryonic dopamine (DA) neurons, a pattern believed to result from decreased survival and reinnervation provided by grafted neurons in the aged host. Advanced age is the primary risk factor for Parkinson's disease (PD).