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Stereological study of amygdala glial populations in adolescents and adults with autism spectrum disorder.

Morgan JT, Barger N, Amaral DG, Schumann CM - PLoS ONE (2014)

Bottom Line: We hypothesized that a reduction in neuron numbers in ASD might relate to altered immune function and/or aberrant microglial activation, as indicated by increased microglial number and cell body volume.Overall, average non-neuronal cell numbers and volumes did not differ between ASD and typically developing brains.There were fewer oligodendrocytes in the amygdala of adult individuals with ASD ages 20 and older compared to typically developing controls.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America.

ABSTRACT
The amygdala undergoes aberrant development in autism spectrum disorder (ASD). We previously found that there are reduced neuron numbers in the adult postmortem amygdala from individuals with ASD compared to typically developing controls. The current study is a comprehensive stereological examination of four non-neuronal cell populations: microglia, oligodendrocytes, astrocytes, and endothelial cells, in the same brains studied previously. We provide a detailed neuroanatomical protocol for defining each cell type that may be applied to other studies of the amygdala in neurodevelopmental and psychiatric disorders. We then assess whether cell numbers and average volumes differ between ASD and typically developing brains. We hypothesized that a reduction in neuron numbers in ASD might relate to altered immune function and/or aberrant microglial activation, as indicated by increased microglial number and cell body volume. Overall, average non-neuronal cell numbers and volumes did not differ between ASD and typically developing brains. However, there was evident heterogeneity within the ASD cohort. Two of the eight ASD brains displayed strong microglial activation. Contrary to our original hypothesis, there was a trend toward a positive correlation between neuronal and microglial numbers in both ASD and control cases. There were fewer oligodendrocytes in the amygdala of adult individuals with ASD ages 20 and older compared to typically developing controls. This finding may provide a possible sign of altered connectivity or impaired neuronal communication that may change across the lifespan in ASD.

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Microglial number and size stereological measures in ASD and typically developing amygdala.Whole amygdala: A. microglial number and B. average microglial somal volume. Two ASD cases with the highest microglial numbers also have the highest microglial volumes. Lateral nucleus: C. microglial number and D. average microglial somal volume. Numbers next to case markers indicate subject age.
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pone-0110356-g005: Microglial number and size stereological measures in ASD and typically developing amygdala.Whole amygdala: A. microglial number and B. average microglial somal volume. Two ASD cases with the highest microglial numbers also have the highest microglial volumes. Lateral nucleus: C. microglial number and D. average microglial somal volume. Numbers next to case markers indicate subject age.

Mentions: Two ASD cases, AN00764 (20 y.o.) and AN02736 (15 y.o.), had average microglial somal volumes that were above the high end of the typically developing control range (by 19.9% and 10.1%, respectively) (Figure 5, Table 2). Examining these cases qualitatively, many of the microglial cells had a strongly activated morphology (Figure 6). These two cases also had the highest microglial numbers of any cases examined, which were ∼4.2% and ∼10.1% above the high end of the control range (Figure 5, Table 2). A third ASD case, AN06746, had a microglial number that was 1.6% above the high end of the control range (Figure 5A, Table 2), but an average microglial volume in the middle of the control range. AN02736 and AN00764 were also outliers for both microglial volume and number in the lateral nucleus specifically (Figure 5C–D).


Stereological study of amygdala glial populations in adolescents and adults with autism spectrum disorder.

Morgan JT, Barger N, Amaral DG, Schumann CM - PLoS ONE (2014)

Microglial number and size stereological measures in ASD and typically developing amygdala.Whole amygdala: A. microglial number and B. average microglial somal volume. Two ASD cases with the highest microglial numbers also have the highest microglial volumes. Lateral nucleus: C. microglial number and D. average microglial somal volume. Numbers next to case markers indicate subject age.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4201518&req=5

pone-0110356-g005: Microglial number and size stereological measures in ASD and typically developing amygdala.Whole amygdala: A. microglial number and B. average microglial somal volume. Two ASD cases with the highest microglial numbers also have the highest microglial volumes. Lateral nucleus: C. microglial number and D. average microglial somal volume. Numbers next to case markers indicate subject age.
Mentions: Two ASD cases, AN00764 (20 y.o.) and AN02736 (15 y.o.), had average microglial somal volumes that were above the high end of the typically developing control range (by 19.9% and 10.1%, respectively) (Figure 5, Table 2). Examining these cases qualitatively, many of the microglial cells had a strongly activated morphology (Figure 6). These two cases also had the highest microglial numbers of any cases examined, which were ∼4.2% and ∼10.1% above the high end of the control range (Figure 5, Table 2). A third ASD case, AN06746, had a microglial number that was 1.6% above the high end of the control range (Figure 5A, Table 2), but an average microglial volume in the middle of the control range. AN02736 and AN00764 were also outliers for both microglial volume and number in the lateral nucleus specifically (Figure 5C–D).

Bottom Line: We hypothesized that a reduction in neuron numbers in ASD might relate to altered immune function and/or aberrant microglial activation, as indicated by increased microglial number and cell body volume.Overall, average non-neuronal cell numbers and volumes did not differ between ASD and typically developing brains.There were fewer oligodendrocytes in the amygdala of adult individuals with ASD ages 20 and older compared to typically developing controls.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry and Behavioral Sciences and the M. I. N. D. Institute, University of California Davis, Sacramento, California, United States of America.

ABSTRACT
The amygdala undergoes aberrant development in autism spectrum disorder (ASD). We previously found that there are reduced neuron numbers in the adult postmortem amygdala from individuals with ASD compared to typically developing controls. The current study is a comprehensive stereological examination of four non-neuronal cell populations: microglia, oligodendrocytes, astrocytes, and endothelial cells, in the same brains studied previously. We provide a detailed neuroanatomical protocol for defining each cell type that may be applied to other studies of the amygdala in neurodevelopmental and psychiatric disorders. We then assess whether cell numbers and average volumes differ between ASD and typically developing brains. We hypothesized that a reduction in neuron numbers in ASD might relate to altered immune function and/or aberrant microglial activation, as indicated by increased microglial number and cell body volume. Overall, average non-neuronal cell numbers and volumes did not differ between ASD and typically developing brains. However, there was evident heterogeneity within the ASD cohort. Two of the eight ASD brains displayed strong microglial activation. Contrary to our original hypothesis, there was a trend toward a positive correlation between neuronal and microglial numbers in both ASD and control cases. There were fewer oligodendrocytes in the amygdala of adult individuals with ASD ages 20 and older compared to typically developing controls. This finding may provide a possible sign of altered connectivity or impaired neuronal communication that may change across the lifespan in ASD.

Show MeSH
Related in: MedlinePlus