Fractal analysis of astrocytes in stroke and dementia

The varied morphological forms in which astrocytes occur in brain of ischemic/hemorrhagic stroke and Alzheimer's disease (AD) patients are complex and the mechanisms that drive their formation are not yet properly understood. Subjective differences can be described between these pathologies in what it concerns astrocyte implication, but these have not been yet subjected to a morphometrical quantification. Here we apply a fractal dimension (FD) analysis algorithm to differentiate both between fibrous, protoplasmatic and activated astroglia; but also between the three pathological conditions studied. Analyzing more than 1000 astroglia, we show here first that FD can clearly differentiate between the three morphological subtypes. Second, we describe resemblances of the FD values for ischemic and hemorrhagic lesions, and significant differences when these are compared to AD patients. These results are further discussed and integrated in what it regards the preferential regions proved to be affected in these conditions, and which parallels our results. This work illustrates that fractal dimension analysis of astroglia is a useful method for quantitatively describing gliosis in different pathologies, and that it may offer more insight into the pathogenesis of brain diseases.